home » Trading » Are there vessels in pine wood? A brief overview of the microscopic structure of wood

Are there vessels in pine wood? A brief overview of the microscopic structure of wood

Cancer of the gastrointestinal tract is very common throughout the world. The frequency of its occurrence is related to the feature modern look people's lives, including the mode and quality of nutrition. Let's look at what is meant by the term gastrointestinal cancer, how to recognize this ailment and how to treat it?

Detection and treatment of gastrointestinal cancer

The gastrointestinal tract (GIT) consists of the following parts:

esophagus (tube that connects the mouth to the stomach)
stomach. It is a bag-shaped organ. The stomach is made up of several sections. Most often, neoplasms occur in the lower (pyloric) section, which has a transition to the small intestine. The stomach is the most common site of localization of oncology among the organs of the gastrointestinal tract.
intestines. It consists of a small and large intestine, which ends with an anus.

Cancer or carcinoma of the gastrointestinal tract is a malignant tumor that develops in the mucous membrane of the digestive tract. The esophagus, stomach, and intestines are connected in single system, so a cancerous tumor of one of them can easily go to another.

Such neoplasms are characterized by fairly rapid growth rates. They germinate the wall of the organ, leading to its deformation, and then can spread to the surrounding structures. Also, cancerous tumors are able to form metastases, that is, secondary tumors in other organs.

A person with carcinoma of the gastrointestinal tract has problems digesting food, which negatively affects the entire body. Perhaps a complete overlap of the lumen of the organ (stenosis). This is a dangerous condition that requires an ambulance.

Another danger of the disease is that the first symptoms of gastrointestinal cancer often occur late, and it is difficult to suspect cancer in the early stages. It is discovered either by chance during examinations, or in a neglected state, when the tumor reaches a large size.

Causes of gastrointestinal cancer

Studies have shown that gastrointestinal carcinoma is more commonly diagnosed in men over 55 years of age. The bacterium Helicobacter pylori plays a role in the development of many ailments, so its presence is a risk factor. Also, the food culture and human diet significantly affect the gastrointestinal tract. Reception of hot, spicy, too salty, poorly chewed food, as well as strong alcoholic drinks negatively affect the digestive system and lead to the development of inflammatory diseases.

There are precancerous conditions against which malignant tumors develop:

ulcers;
gastritis;
metaplasia;
leukoplakia;
Barrett's esophagus
ulcerative colitis;
pernicious anemia;
duodenogastric reflux;
adenomatous polyps;
Menetrier's disease;
sideropenia.

Malignant transformation occurs due to changes in the structure of the mucous membrane that occur under the influence of a long-term inflammatory process. It may not happen immediately, but after a long time.

Interesting fact! Chronic gastritis causes stomach cancer in 70-80% of cases!

Other risk factors for the disease are:

smoking;
obesity;
lack of vitamins and microelements in food, drinking water with nitrites and nitrates;
oncology in the family;
damage to the esophagus and stomach by chemicals;
atrophy of the stomach;
hereditary diseases (neurofibromatosis 1, multiple neoplasia type 1, Gordner's syndrome, Lynch's syndrome, etc.).

There are also cases of tumor development after operations on the digestive tract.

Classification of gastrointestinal cancer

Gastrointestinal tumors are classified according to location.

cancer of the cervical and upper thoracic esophagus;
cancer of the middle part;
lower chest;
abdominal.

Currently, the method of hormone therapy is being developed: the patient is injected with somatostatin analogues. This prevents the tumor from producing hormones and slows down its growth.

Additionally, during the treatment of gastrointestinal cancer, immunotherapy with interferon can be carried out. It stimulates the human immune system, helping the body to work better and fight tumor intoxication.

Metastasis and recurrence in gastrointestinal cancer

Metastases from cancer of the stomach, intestines, or esophagus spread in several ways:

Implantation (there is an increase in the volume of the tumor and germination in neighboring structures);
Hematogenous (cancer cells break away from the primary tumor, enter the bloodstream and spread through the bloodstream to any part of the body);
Lymphogenically (through the lymphatic system).

Metastatic tumors have the same shape as the primary neoplasm. The path of their dissemination depends on the localization of the oncoprocess. So, neoplasms of the esophagus first spread through the lymphatic vessels, which are located in the submucosal layer. They can be found 5 and even 10 cm from the visible edge of the tumor. Next, metastasis occurs to the lymph nodes (cervical, paraesophageal, tracheobronchial, paracardial). Distant metastases are more often found in the liver, lungs, and skeletal system.

Metastases in gastric cancer usually spread through the lymphogenous route. First, the lymph nodes located in the ligaments of the stomach are affected, then the retroperitoneal ones, and at the end, metastasis occurs to distant organs (small intestine, pancreas, liver, large intestine).

Metastases are treated surgically. In this case, the affected organ can be removed. With liver metastases, liver transplantation or hepatic artery embolization is performed. Treatment also includes powerful chemotherapy drugs.

Prognosis for gastrointestinal cancer

The prognosis of life in gastrointestinal cancer depends on the following factors:

the location of the tumor and its size;
the presence of metastases in the lymph nodes, liver and other organs;
Is it possible to surgically remove the neoplasm?

With esophageal carcinoma, the average 5-year survival rate after complex radical treatment is 56%, with stomach tumors - 25%, with intestinal carcinoma - 40-50%.

Such indicators are explained by the fact that most patients come with stage 3-4. Stages 1 and 2 are rarely observed, but if a high-quality operation is performed during this period, then 80-90% 5-year survival and about 70% 10-year survival can be achieved.

Untreated cancer has a poor prognosis. Such people live a maximum of 5-8 months. helps to live several years, and some even more than 5 years.

Disease prevention

Prevention of gastrointestinal cancer includes a balanced diet. It is necessary to eat vegetables and fruits, drink more green tea. If you do not want to get sick, then alcohol and cigarettes should be abandoned altogether.

Since the symptoms of the disease in the early stages are subtle, doctors need to be more alert about oncology and, in case of the slightest suspicion, refer the person for an extensive examination.

In the presence of precancerous diseases, it is necessary to treat them in time, and then regularly examine them.

Informative video:

- a polymorphic group of neoplasms affecting all layers of the stomach, having a different degree of proliferative activity and impact on the health and life of the patient. The main signs of gastric cancer include weakness, emaciation, digestive discomfort, loss of appetite, anemia, depression, and loss of interest in life. To detect tumors, X-ray and endoscopic techniques, ultrasound, CT and MRI of the abdominal organs are used. The treatment of this pathology is mainly surgical; if a malignant neoplasm is detected, combined therapy also includes radiation and polychemotherapy.

General information

Tumors of the stomach may differ in the nature of tumor growth, origin, degree of differentiation. Among all neoplasms of the stomach, benign tumors occur in no more than 4% of cases, the vast majority of them are gastric polyps. Among malignant tumors, gastric cancer is most often detected; other types of malignant neoplasms account for no more than 5%. The ratio of men and women among patients with oncopathology of the stomach is 3:2. The age bar is shifted towards the elderly: more than two-thirds are patients over 50 years old. IN last years the incidence of stomach cancer has decreased significantly, and gastroenterologists attribute this to the timely detection and eradication of Helicobacter pylori infection. It is known that it is H.pylori that plays a leading role in the formation of gastric and duodenal ulcers, and a long-term ulcer can become malignant and lead to the development of gastric cancer.

Classification of tumors of the stomach

According to the degree of differentiation, gastric tumors are divided into benign and malignant. Further division within these groups is carried out according to the type of tissue from which this tumor formation originates. Among benign gastric tumors, most are represented by polyps - glandular neoplasms growing in the lumen of the stomach, having a rounded shape, a thin stalk or a wide base. According to the quantitative criterion, a single polyp, multiple polyps, polyposis of the stomach (a hereditary disease characterized by damage to the mucous membrane of the digestive tract) are isolated.

By structure, polyps are adenomatous (originate from the glandular epithelium of the stomach, in 20% of cases they transform into cancer, especially when the polyp is larger than 15 mm); hyperplastic (develop against the background of atrophic gastritis, make up more than 80% of all polyps, very rarely malignant); inflammatory-connective tissue (infiltrated by eosinophils, are not true tumors, but outwardly very similar to the oncological process). Separately, Menetrier's disease is distinguished - a precancerous condition, which is described as polyadenomatous gastritis. Benign tumors of the stomach can originate from various tissues: muscle (leiomyoma), submucosal layer (lipoma), blood vessels (angioma), nerve fibers (neurinoma), connective tissue (fibroma), etc.

Most malignant tumors of the stomach (more than 95% of cases) are represented by adenocarcinoma (gastric cancer of epithelial origin). Other tumors include carcinoid (has a neuroendocrine origin, the tumor is capable of producing hormones), leiomyoblastoma (contains cells resembling both epithelioid and smooth muscle), leiomyosarcoma (consists of transformed smooth muscle cells), malignant lymphoma (comes from degenerated lymphoid tissue) . Less commonly, gastric tumors such as fibroplastic and angioplastic sarcoma, retinosarcoma, and malignant neurinoma can be detected.

Causes of stomach tumors

To date, the exact causes of the transformation of normal tissues into a stomach tumor have not yet been identified. However, in gastroenterology, the main predisposing factors and conditions that most likely lead to the formation of oncopathology have been identified.

Predisposing factors are basically the same for both malignant and benign neoplasms. These include chronic Helicobacter pylori infection, atrophic gastritis, genetic predisposition (presence of gastric oncopathology in relatives, detection of the IL-1 gene), malnutrition, smoking and alcoholism, living in an ecological disaster zone, immunosuppression. The presence of gastric polyps (adenomatous), resection of a part of the stomach, pernicious anemia, and Menetrier's disease also predispose to malignant transformation.

Symptoms of stomach tumors

Benign tumors of the stomach most often do not manifest themselves in any way and are discovered by chance during an examination for another pathology. Large polyps can manifest as aching pain in the epigastric region after eating; nausea and vomiting with streaks of blood; heartburn and belching; weakness; dizziness (against the background of anemia, gastric bleeding); frequent change of constipation and diarrhea. Symptoms of leiomyomas appear in case of necrosis of the tumor node and internal bleeding. In this situation, the patient is concerned about weakness, pallor, dizziness.

Signs of malignant tumors of the stomach can occur both against the background of complete health, and accompany the symptoms of peptic ulcer, chronic gastritis. In the early stages of stomach cancer, the patient notes a decrease in appetite, pain and a feeling of fullness in the stomach after eating, progressive emaciation, taste perversion and refusal of certain foods because of this. In the later stages of the disease, cancerous intoxication develops; there is an increase in abdominal pain against the background of tumor germination of neighboring organs; vomiting of food eaten the day before; melena (stool with altered blood); enlargement of regional lymph nodes.

Complications of a benign oncoprocess include malignancy; germination of the tumor wall of the stomach with perforation and the development of peritonitis; overlapping of the lumen of the stomach with a tumor conglomerate with a violation of the passage of the food bolus; ulceration of the tumor with disintegration and bleeding from the tumor node; migration of a polyp on a leg into the duodenum with infringement and necrosis of the polyp.

Malignant tumors of the stomach are also complicated by narrowing of the stomach cavity, ulceration and bleeding, and gastric perforation. In addition, metastasis, rapid emaciation with the development of cancer cachexia are characteristic of malignant tumors.

Diagnosis of tumors of the stomach

In previous years, the main method for diagnosing a tumor of the stomach was radiography, but today endoscopic studies come to the fore. Nevertheless, one cannot deny the informativeness and wide possibilities of radiography - in some clinics it still remains the main diagnostic technique. Panoramic radiography of the abdominal organs allows suspecting a tumor due to deformation of the contours of the stomach, displacement of neighboring organs. For a more accurate diagnosis, contrast studies are used (radiography of the stomach with double contrasting) - during such a study, various filling defects are detected, indicating the presence of a tumor growing in the cavity of the organ, or mucosal defects, indicating malignancy and decay of the neoplasm.

A consultation with an endoscopist is needed to visualize the tumor process and prescribe esophagogastroduodenoscopy and endoscopic biopsy. Carrying out a morphological study allows you to establish the correct diagnosis and start timely treatment in 95% of cases. To clarify the prevalence of the tumor conglomerate, the degree of involvement of surrounding organs and the presence of metastases, it is possible to perform ultrasound, CT and MSCT of the abdominal organs. Clinical and biochemical analyzes make it possible to assess the general condition of the patient, the degree of tumor intoxication.

Treatment of stomach tumors

Tactics in relation to the treatment of benign and malignant tumors of the stomach are somewhat different. Removal of benign tumors of the stomach is usually performed surgically. With regard to gastric polyps, gastroenterologists can take a wait-and-see approach, although more often a decision is made to remove gastric polyps during endoscopy with simultaneous intraoperative histological examination. Finding out the morphological characteristics of the removed benign tumor allows you to make a decision - to resect only the polyp or also the adjacent mucosa. If during endoscopic examination a total polyposis of the stomach is detected, a gastrectomy is performed. After removal of a benign tumor, a course of treatment with proton pump inhibitors, anti-Helicobacter drugs is prescribed.

Treatment of malignant neoplasms of the stomach is usually complex, including surgery, radiation and polychemotherapy. To date, the most effective method of therapy is surgery. The volume of surgical intervention depends on many factors: the type and size of the tumor, the prevalence of the oncological process, the presence and number of metastases, the involvement of surrounding organs, and the general condition of the patient.

In the presence of a malignant neoplasm, a radical operation or palliative intervention can be performed. Radical surgery involves removal of the tumor, total gastrectomy, resection of the omentum (omentectomy) and the surrounding organs involved in the process, the lymph nodes. Palliative operations are aimed at alleviating the general condition and providing enteral nutrition for the patient. The complex treatment of malignant neoplasms usually includes radiation, chemotherapy to achieve the best result, to prevent tumor recurrence.

Forecast and prevention of tumors of the stomach

The prognosis for the detection of benign neoplasms is favorable; however, since these tumors are prone to recurrence, patients are under dispensary observation throughout their lives. Establishing the malignant nature of the tumor significantly worsens the prognosis. The chances of recovery are much higher with timely diagnosis and treatment of a malignant tumor. When metastases are detected, germination of neighboring organs, the prognosis for life worsens significantly.

There is no specific prevention of stomach tumors. To prevent the formation of an oncological process, provoking factors should be excluded: establish a diet, refuse bad habits, promptly identify and treat inflammatory diseases of the stomach, regularly undergo endoscopic examination in the presence of a family predisposition to oncopathology. Upon reaching the age of 50, you should undergo an annual examination by a gastroenterologist.

Of all the pathologies of the gastrointestinal tract, diseases of the stomach occupy the first place. Among them, tumors are highlighted, which are the least common, but have serious consequences for human health.

Tumors of the stomach have a different etiology, mechanisms of development and the degree of influence on the body. According to these characteristics, two groups of neoplasms are distinguished: benign and malignant.

Of all the formations localized in the stomach, only 4% are benign tumors. As a rule, they have a smoothed symptomatology and can affect all layers of the tissues of the stomach. The bulk of benign formations are polyps, which also have a subspecies division.

polyps

Polyps are formations from glandular tissue growing in the cavity of the stomach. They have a rounded body, located on a thin elongated leg with a wide base. This disease may differ in the presence of formations in the cavity.

According to this criterion, single polyp, multiple e their education and wall polyposis stomach, which completely affects the entire mucosa of the organ, leading to a change in its structure.

Polyps may differ in their structure. According to this parameter, the following types are distinguished:

adenomatous. Polyps are localized only within the epithelium of the stomach and can grow more than 1.5 cm. With extensive growth or an increase in the tumor of more than 2 cm, the disease becomes malignant in 20% of cases;
hyperplastic. It makes up 80% of all types of polyps and is a consequence of chronic atrophic gastritis. Go to the cancerous stage in isolated cases;
inflammatory-connective tissue. It affects not only the epithelium, but also the connective tissue. It is characterized by infiltration by eosinophils and signs of malignancy.

Among all types of polyps, Menetrier's disease is distinguished separately. She is characterized by all the signs of polyadenomatous gastritis, but with a burdened history, which puts her in a number of precancerous conditions.

Polyps are also divided according to the place of localization into 5 types, which are formed in:

muscle tissues of the walls of the stomach. Polyps can form both on the surface of the muscle and its deep layers. This species is called leiomyoma;
submucosal layer. A tumor that forms in this layer is defined as a lipoma;
vessels. It affects the vessels located on the surface of the organ cavity. Classified as an angioma;
nerve fibres. It is called neurinoma and affects only the nervous tissues of the stomach;
connective tissue. It belongs to fibromas and tends to grow into muscles.

Polyp (benign tumor)

Malignant

Malignant tumors can be reborn both from benign tumors and be an independent disease that can be triggered by various reasons. Depending on the mechanism of development, location and structure of education, there are several types of gastric cancer.

Adenocarcinoma

The most common malignant formation of the stomach, occurring in 95% of cases. The tumor affects the glandular tissue of the mucous organ, which is responsible for the production of mucus and gastric juice. For the beginning of this type of pathology, the absence of specific symptoms is characteristic.

In the future, it will depend on internal location tumors:

Her localization in the area of the body of the organ does not affect the functioning of the stomach until it reaches a large size and is most often manifested by constant heaviness after eating.
Formation outlet for antral cancer leading to rapid onset of symptoms.
At cardiac adenocarcinoma with the defeat of the upper section, problems with swallowing food appear.

Adenocarcinoma is characterized by rapid development and germination in the nearest organs.

Carcinoid

Carcinoid is one of the rarest types of gastrointestinal cancer and is characterized by slow growth. Clinically, the tumor resembles a benign one, but with active phase of metastasis. Most often affects people old age.

Unlike other formations, it has hormonal activity, thanks to which pathology can be detected at the initial stages by clinical tests. The tumor is characterized by pain, most often of an acute nature and a distant stage of the formation of secondary tumors.

Leiomyoblastoma

As well as carcinoid, it is a rare disease diagnosed in only 0.6% of cases. The tumor belongs to neuroendocrine diffuse system localized in the muscle tissue of the organ.

Leimioblastoma can reach large sizes, completely overlapping stomach cavity. Pathology is unpredictable and can be in a passive form of growth for several years. It is characterized by rare single metastasis.

Removed malignant tumor

Leiomyosarcoma

In leiomyosarcoma, the tumor forms in deep layers muscle tissue, in the form of a limited clear compaction with numerous expressions. Mainly affected posterior and anterior wall of the stomach.

Pathology is rarely manifested by symptoms of malignancy, which allows it to be detected only in the last stages. As a rule, adjacent organs and the lymphatic system are rarely affected during metastasis. Most often, secondary formations are localized in distant parts of the body.

Lymphoma

With lymphoma, the degeneration of the lymphatic cells of the stomach is characteristic, with damage to its various departments. On the early stages, the disease manifests itself as gastritis or ulcers. More pronounced symptoms appear only at stages 3 and 4, when the lesion becomes extensive.

In its features, lymphoma is similar to adenocarcinoma, which often leads to incorrect initial diagnosis.

Fibroplastic sarcoma

It develops in the connective tissue of the stomach, forming in it strands and cells, with limited localization. The affected area is represented by dense tissue, with partial infiltration into the walls of the organ. At the same time, there is a pronounced thickening of the submucosal and muscular layers. Most often, it affects the pyloric area, leading to its pathological narrowing

Angioplastic sarcoma

Sarcoma of this type is formed in the epithelium of the cavity and is characterized by extensive proliferation of blood vessels. As a result, from the very beginning of the development of the tumor, the appearance of blood in the feces or saliva is noted.

As the formation develops, it affects all the tissues of the stomach and grows beyond it. As a rule, pathology is accompanied by the appearance of spots or plaques on the skin and mucous membranes, which are painful.

Retinosarcoma

It is characterized by slow growth and a limited area of metastasis. It develops mainly on the gastric mucosa, with damage to blood vessels the entire cavity. Characterized by education scar tissue in the area of localization, which leads to exfoliation of the mucosa and the formation of pathological connective tissue.

Neurinoma

Neurinoma is characterized by slow growth and late metastasis. Most often, the tumor is localized in the antrum and, when it grows, leads to inability to eat.

Neurinoma is characterized by multiple formation in one area and invasion into the duodenum and also in the walls of the stomach. Neurinoma is asymptomatic, and only with the formation of ulcers at the site of the lesion, it can be manifested by the appearance of blood and soreness.

stomach during surgery

Complications

The development of stomach tumors, as a rule, passes with the appearance of a number of complications:

Malignancy. It is typical for benign tumors that develop with a decrease in the level of differentiation, morphological changes in tissues that become malignant.
Perforation. It is the formation of a through hole in the abdominal cavity, into which the contents of the stomach are poured out. It is manifested by severe constant pain and nausea.
Peritonitis. It is a purulent complication of the abdominal cavity caused by perforation of the stomach. It is manifested by a sharp increase in temperature and severe pain.
Covering the lumen of the stomach. Occurs due to the strong growth of the tumor, which does not allow for a full meal.
The collapse of the tumor. It leads to the accumulation of dead tissues in the stomach cavity and intoxication, which is accompanied by nausea and vomiting.
polyp necrosis characterized by the gradual death of its tissues, which causes intoxication of the body, temperature and inflammation of the walls of the organ.
Migration of the polyp into the intestine. Is an common cause intestinal inflammation.

Causes

The reasons that provoke the development of neoplasms include:

Exposure to radiation or toxic substances that lead to DNA mutation and weakening of the immune system. The combination of these factors leads to the formation of malignant tumors.
Infection with the bacterium Helicobacter pylori. It leads to the formation of ulcers and gastritis, which in turn provoke the growth of tumors.
Wrong nutrition. It affects the integrity of the mucosa, on which fibrous tissue is formed from frequent injury.
hereditary factor. Increases the risk of developing cancer by 20%.

signs

Regardless of the nature of the formations, they have some common symptoms:

fast fatiguability;
constant weakness;
sudden weight loss;
depression;
anemia;
increase in body temperature.

Benign tumors are characterized by specific symptoms:

discomfort in the stomach, which gradually turns into pain;
nausea or vomiting;
heartburn;
stool disorder, which often changes its character.

Malignant neoplasms are determined by the following symptoms:

retrosternal pain, extending to the region of the heart;
vomit;
frequent belching;
bleeding or blood in the stool;
difficulty swallowing food;
diarrhea or constipation.

Comprehensive information about the symptoms of stomach cancer is contained in this video:

Diagnostics

The following methods are used to diagnose neoplasms:

x-ray. It is used to determine metastases in cat tissue;
endoscopy. Allows you to study in detail the walls of the organ and identify the degree of tumor growth;
esophagogastroduodenoscopy. Designed to study the cavity of the stomach and its exit, as well as for biopsy;
Endoscopic biopsy. It is carried out using a flexible endoscope to obtain tissues for histological and cytological examination.

Treatment

Treatment of tumors is prescribed in accordance with the nature of the neoplasm. Removal a malignant tumor is carried out immediately after detection, and a benign one, only with its active growth. Radiation and polychemotherapy, shown only in cancerous pathologies. Courses and dosage are prescribed in individually depending on the degree of growth.

Forecast

The prognosis for the treatment of benign tumors is 100% positive. At no treatment, only 23% neoplasms become malignant. In the case of cancerous pathologies of the stomach, only in 40% patients diagnosed disease in the early stages with the possibility of surgical removal.

After operation, 70% survive after 5 years patients. Without surgical treatment, only 12% patients, and only 40% manage to live more than 5 years.

Bowel oncology – this disease is very serious. The intestine is part of the digestive system and consists of the large and small intestines.

After the food is digested in the stomach, it enters the large intestine, where nutrients are absorbed from it, and water is taken up in the colon. Waste after digestion of food accumulate in the rectum, then excreted from the body.

The main factors in the formation of the disease are malnutrition, intestinal diseases and hereditary predisposition.

If we talk about malnutrition, then scientists are sure that it affects the development of cancer in the colon. Foods rich in animal proteins and fats increase the risk of cancer if eaten without fruits and vegetables. People who abuse alcohol are at risk of developing cancer.

How does hereditary predisposition affect the formation of oncology in the rectum? If you have had bowel cancer in your family, then you may be predisposed to this disease. It should be especially feared for those who have very close relatives who had bowel cancer before the age of 45. And the more cases of this disease in the family, the greater the risk of the disease. If you have such a predisposition, then it makes sense to contact a specialized clinic. There you will calculate the likelihood of cancer. If you are at risk, then you should not expect the first signs of the disease, but should be regularly examined with a colonoscopy.

Specialists highlight two genetic conditions in which there is a high risk of colon cancer: hereditary adenomatosis-polyposis in the lining of the colon and hereditary non-polished colon cancer. The first case is characterized by the presence of a large number of benign tumors, and in the second, cancer can develop simultaneously in several places.

As for intestinal diseases, they increase the risk factor for oncology of diseases of the lining of the intestine and ulcerative colitis. How to recognize bowel cancer? Apart from listed factors the following indicators are present: the presence of excess weight, excessive smoking, a passive lifestyle.

What are the symptoms of bowel cancer?

You should be aware that the symptoms of colon cancer and rectal cancer are slightly different (you can also read about). The first symptoms of colon cancer are:

Blood in and on feces
Diarrhea or constipation for more than a month and a half
Sudden weight loss
Pain in the abdomen and anus
Bowel obstruction
Feelings of incomplete bowel movements
Symptoms of rectal cancer include:
Blood, mucus and pus in stool
Pain in the lower back, coccyx, sacrum and perineum
Painful and frequent urge to defecate
Sensation of the presence of something in the rectum
Ribbon-shaped stool
Persistent constipation

It should be noted that such symptoms are manifested not only in the case of cancer of the colon and rectum. The disease usually occurs in people over 50 years of age. In younger people, these symptoms may indicate the presence of other diseases, such as IBS or ulcerative colitis.

However, it is worth noting that the expression of such symptoms for several weeks, with clearly increasing signs, is a reason to consult a doctor. Now you know what bowel oncology is, about the symptoms that accompany it and about the possibility of a prompt response to the initial stage.

A few words about stomach cancer

Gastric cancer is the most common disease in oncology. . Its main danger lies in the complexity of early diagnosis. The fact is that in the early stages of this disease is characterized by mild symptoms. Therefore, patients do not pay attention to him. In later stages, stomach cancer is difficult to treat. In terms of mortality, this disease ranks second among oncological diseases after lung cancer.

But if treatment is carried out at an early stage, then the likelihood of recovery is very high. Therefore, it is very important to be aware of the first signs of stomach cancer, and if necessary, undergo a complete examination.

Symptoms of the disease depend on the location of the tumor and its type. If the tumor is located in the cardinal section of the stomach, then the ingestion of large or coarse food and increased salivation worsen.

With the growth of the tumor, these symptoms become brighter, pain, vomiting, a feeling of heaviness in the area of the shoulder blades, heart and chest also appear. If the tumor appeared in the antrum of the stomach, then vomiting, a feeling of heaviness, and a rotten breath appear. With the defeat of the middle part of the stomach at an early stage, there are no special signs. Patients generally feel weakness, lack of appetite, anemia, lose weight.

I want to note that the early symptoms of stomach cancer lead to the treatment of other diseases. The fact is that these symptoms are inexpressive, and besides, they often appear in other diseases of the gastrointestinal tract. Therefore, it makes sense to undergo a more thorough diagnosis.

Chemical composition

Chemical composition certain types tree species, as well as their parts, is qualitatively similar, but there are significant differences in the quantitative content of individual components. There are also individual features in the quantitative content of individual components within one species, associated with age and growing conditions. Wood is made up of organic substances, which include carbon, hydrogen, oxygen and some nitrogen. Absolutely dry pine wood contains on average: 49.5% carbon; 6.1% hydrogen; 43.0% oxygen; 0.2% nitrogen.

In addition to organic substances, wood contains mineral compounds that produce ash during combustion, the amount of which varies between (0.2-1.7)%; however, in some species (saxaul, pistachio kernels), the amount of ash reaches (3--3.5)%. In the same breed, the amount of ash depends on the part of the tree, position in the trunk, age and growing conditions. More ash is given by the bark and leaves; Branch wood contains more ash than trunk wood; for example, birch and pine branches produce 0.64 and 0.32% ash during combustion, and stem wood - 0.16 and 0.17% ash. The wood of the upper part of the trunk gives more ash than the lower; this indicates a high ash content in young wood.

The composition of the ash includes mainly salts of alkaline earth metals. Pine, spruce and birch wood ash contains over 40% calcium salts, over 20% potassium and sodium salts, and up to 10% magnesium salts. Part of the ash from 10 to 25% is soluble in water (mainly alkalis - potash and soda). In the past, K 2 CO 3 potash, used in the production of crystal, liquid soap and other substances extracted from wood ash. Ash from the bark contains more calcium salts (up to 50% for spruce), but less salts of potassium, sodium and magnesium. The main chemical elements (C, H and O) included in the composition of wood and the above-mentioned basic chemical elements form complex organic substances.

The most important of them form a cell membrane (cellulose, lignin, hemicelluloses - pentosans and hexosans) and make up 90--95% of the mass of absolutely dry wood. The remaining substances are called extractive, that is, extracted by various solvents without a noticeable change in the composition of the wood; of these, tannins and resins are the most important. The content of basic organic substances in wood depends to some extent on the species. This can be seen from table 2

Table 2 - The content of organic substances in wood of different species

On average, it can be assumed that in wood conifers contains (48--56)% cellulose, (26--30)% lignin, (23--26)% hemicelluloses containing (10--12)% pentosans and about 13% hexosans; at the same time wood hardwood contains (46--48)% cellulose, (19--28)% lignin, (26--35)% hemicelluloses containing (23--29)% pentosans and (3--6)% hexosans. Table 2 shows that coniferous wood contains an increased amount of cellulose and hexosans, and hardwood wood is characterized by a high content of pentosans. In the cell membrane, cellulose is in combination with other substances. A particularly close relationship, the nature of which is still not clear, is observed between cellulose and lignin. Previously, it was believed that lignin was only mechanically mixed with cellulose; however, in Lately more and more come to the conclusion that between them there is a chemical bond.

The chemical composition of early and late wood in the annual layers, that is, the content of cellulose, lignin and hemicelluloses, is almost the same. Early wood contains only more substances soluble in water and ether; this is especially true for larch. The chemical composition of wood varies little along the height of the trunk. So, in the composition of oak wood, no practically tangible differences were found in the height of the trunk. In pine, spruce and aspen at the age of maturity, a slight increase in the content of cellulose and a decrease in the content of lignin and pentosans in the middle part of the trunk were found. The wood of pine, spruce and aspen branches contains less cellulose (44--48)%, but more lignin and pentosans. However, no significant differences were found in oak chemical composition wood of the trunk and large branches, only in small branches were found less tannins (8% in the trunk and 2% in the branches). The difference in the chemical composition of sapwood and summer oak heartwood can be seen from the data in Table 3.

Table 3 - The difference in the chemical composition of sapwood and pine kernel wood

As we see from the table, a noticeable difference was found only in the content of pentosans and tannins: there are more of them in the wood of the kernel (and less ash). The chemical composition of the cell membranes of the cambium, newly formed wood and sapwood varies greatly: the content of cellulose and lignin sharply increases in the elements of wood (in ash from 20.2 to 4.6% in cambium, to 58.3 and 20.9% in sapwood). ), but the content of pectins and proteins also sharply decreases (from 21.6 and 29.4% in cambium to 1.58 and 1.37% in sapwood). The influence of growing conditions on the chemical composition of wood has been little studied.

Cellulose is a natural polymer, a polysaccharide with a long chain molecule. The general formula of cellulose is (C 6 H 10 O 5) n, where n is the degree of polymerization from 6000 to 14000. It is a very stable substance, insoluble in water and common organic solvents (alcohol, ether and others), white. Bundles of cellulose macromolecules - the thinnest fibers are called microfibrils. They form the cellulose framework of the cell wall. Microfibrils are oriented mainly along the long axis of the cell, between them there is lignin, hemicelluloses, and also water. Cellulose consists of long chain molecules formed by repeating units consisting of two glucose residues. Each pair of glucose residues linked together is called a cellobiose. Glucose residues are formed after the release of a water molecule when glucose molecules are combined during the biosynthesis of cellulose polysaccharide. In cellobiose, glucose residues are rotated by 180 0, the first carbon atom of one of them is connected to the fourth carbon atom of the neighboring link.

Considering cellulose at the molecular level, we can say that its macromolecule has the form of an elongated non-planar chain formed various structures links. The presence of various units is associated with weak intramolecular bonds between hydroxyl groups (OH-OH) or between a hydroxyl group and oxygen (OH-O).

Cellulose has 70% crystalline structure. Compared to other linear polymers, cellulose has special properties, which is explained by the regularity of the macromolecule chain structure and significant forces of intra- and intermolecular interaction.

When heated to the decomposition temperature, cellulose retains the properties of a glassy body, that is, it is characterized mainly by elastic deformations. Cellulose is a chemically stable substance; it does not dissolve in water and most organic solvents (alcohol, acetone, etc.). Under the action of alkalis on cellulose, physicochemical processes of swelling, rearrangement and dissolution of low molecular weight fractions proceed simultaneously. Cellulose is not very resistant to the action of acids, which is due to glucosidic bonds between the elementary units. In the presence of acids, hydrolysis of cellulose occurs with the destruction of chains of macromolecules. Cellulose is a white substance with a density of 1.54 to 1.58 g/cm 3 .

The concept of hemicellulose combines a group of substances that are similar in chemical composition to cellulose, but differ from it in the ability to easily hydrolyze and dissolve in dilute alkalis. Hemicelluloses are mainly polysaccharides: pentosans (C 5 H 8 O 4) n and hexosans (C 6 H 10 O 5) n with five or six carbon atoms in the main link. The degree of polymerization of hemicelluloses (n = 60-200) is much less than that of cellulose, i.e., the chains of molecules are shorter. During the hydrolysis of hemicellulose polysaccharides, simple sugars (monosaccharides) are formed; hexosans are converted to hexoses, and pentosans to pentoses. Usually, hemicelluloses are not obtained from wood in the form of marketable products. However, in the chemical processing of wood, they are widely used to obtain many valuable substances. For example, when wood is heated with twelve percent hydrochloric acid, almost all pentosans (93-96)% are converted into simple sugars - pentoses - and after the removal of three water molecules from each monosaccharide molecule, furfural is formed - a product widely used in industry. In a growing tree, hexosans are reserve substances, and pentosans perform a mechanical function.

In addition to carbohydrates (cellulose and hemicellulose), the cell wall contains an aromatic compound, lignin, which has a high carbon content. Cellulose contains 44.4% carbon, and lignin (60--66)%. Lignin is less stable than cellulose, and easily goes into solution when wood is treated with hot alkalis, aqueous solutions of sulfurous acid or its acidic salts. This is the basis for obtaining technical cellulose. Lignin is obtained in the form of waste during the cooking of sulfite and sulfate pulp, during the hydrolysis of wood. The lignin contained in black alkalis is mainly burned during regeneration.

Lignin is used as a pulverized fuel, a substitute for tannins, in the production of molding earth binders (in the foundry industry), plastics, artificial resins, for the production of activated carbon, vanillin, and others. However, the question of the full qualified chemical use of lignin has not yet been resolved. Of the remaining organic substances contained in wood, resins and tannins have received the greatest industrial use.

Resin refers to hydrophobic substances soluble in neutral non-polar solvents.

This group of substances is usually divided into water-insoluble resins (liquid and solid) and gum resins containing water-soluble gums. Among liquid resins, the most important is resin, which is obtained from wood (sometimes from the bark) of conifers as a result of tapping. The tapping of pine and cedar is carried out as follows. In autumn, a vertical groove is made with special tools on a section of the trunk cleared of coarse bark, and with the onset of warm weather in the spring, strips of bark and wood directed at an angle of 30 ° to the groove are systematically removed and the so-called shovels are formed. The depth of the warp is usually (3--5) mm. The wound inflicted on a tree by tapping is called a karra.

From the cut resin passages, the resin, which is under pressure (10-20) atmospheres, flows into the shoes and goes along the groove to the receiver. After applying four to five new pieces, the resin is selected from the conical receiver with a steel spatula. To increase the yield of resin, chemical stimulants (chlorine or sulfuric acid) are used, which are used to treat the freshly opened wood surface.

Spruce tapping is carried out by applying carr in the form of narrow longitudinal strips. To obtain resin from larch, channels are drilled deep into the trunk until they encounter large resin "pockets", which often form in the lower part of the trunk. Larch resin is highly valued and is used in the paint and varnish industry for the manufacture of the best varieties of varnishes and enamel paints. Fir resin is extracted from the "blisters" that form in the bark. The resin from the pierced "blisters" is squeezed out into portable receivers. Fir resin resembles Canadian balsam in its properties and is used in optics, microscopic technology, and the like.

Pine resin is extracted in the largest quantities, which is a transparent resinous liquid with a characteristic pine smell. In the air, resin hardens and turns into a brittle whitish mass - barras. The pine resin obtained as a result of tapping contains approximately 75% rosin and 19% turpentine, the rest is water. Gum can be considered as a solution of solid resin acids (rosin) in liquid turpentine oil (turpentine). Recycling resin is carried out at rosin-turpentine plants and consists in distillation with water vapor of the volatile part - turpentine. The remaining non-volatile part is rosin.

Turpentine and rosin can be obtained by extraction processing of stump resin - the heart part of pine stumps enriched with resin due to rotting of low-resin sapwood. Gasoline is most often used as a solvent. The resulting extract is distilled. The solvent and turpentine are distilled off, and the rosin remains. Extraction products are inferior in quality to turpentine and rosin obtained from resin. Turpentine is widely used as a solvent in the paint and varnish industry, for the production of synthetic camphor and other products. Camphor is used in large quantities as a plasticizer in the production of celluloid, lacquers and film.

The main consumer of rosin is the soap industry, where it is used to make laundry soap. In large quantities, rosin glue is used for sizing papers. Glycerin ester of rosin is introduced into the composition of nitro-varnishes to give the film shine. Rosin is used for the preparation of electrical insulating materials, in the production of synthetic rubber, etc. Larch gum is of great industrial importance. Gum is extracted from crushed wood with acidic water (acetic acid concentration 0.2%) at a temperature of 30 °. After evaporation to a concentration of (60--70)%, a commercial product is obtained. It is applied in textile industry for the manufacture of paints, in the printing, paper industry.

The concept of tannins or tannins combines all substances that have the properties of tanning raw leather, giving it resistance to decay, elasticity, and the ability not to swell. The most rich in tannins is the wood of the oak core from 6 to 11% and chestnut from 6 to 13%. The bark of oak, spruce, willow, larch and fir contains from 5 to 16% tannins. The growths on oak leaves - galls contain from 35% to 75% tannins (one of the varieties of tannins). In the leaves and roots of bergenia, the content of tannins is (15-25)%.

Tannins are soluble in water and alcohol, have an astringent taste, when combined with iron salts they give a dark blue color, and are easily oxidized. Tannins are extracted with hot water from crushed wood and bark. The marketable product is either a liquid or dry extract, which is obtained after the solution has been evaporated in a vacuum apparatus and dried. Essential oils, lactoresins and dyes can also be obtained from woody plants.

Essential oils belong to the group of terpenoids (isoprenoids) - hydrocarbons built from a different number of isoprene units.

From needles and cones different types fir trees extract fir oil, which is a transparent, colorless aromatic liquid that quickly evaporates in air. The needles of the Siberian fir contain from 0.63 to 3%, and the needles of the Caucasian fir 0.2% fir oil. Fir oil has applications in pharmaceutical production, in perfumery and for the preparation of varnishes. Volatile essential oils of coniferous species of pine, spruce, western thuja, have the properties of phytoncidity, that is, the ability to kill microbes in the air or in water.

Pine buds contain essential oil, resins, starch, tannins, pinipicrin. The needles contain a lot of ascorbic acid, tannins, and also contain alkaloids, essential oil. Gum contains up to 35% essential oil and resin acids. In medicine, pine buds are used in the form of infusion, tincture, decoction, extract as an expectorant, diuretic, disinfectant, anti-inflammatory and antiscorbutic agent. Pine buds are integral part breast collection; in combination with coniferous needles in the form of infusion and extract, they can be used to prepare coniferous baths. Polyprenol -- active ingredient pine needles has an antiserotonergic effect. Coniferous needles are used to prepare concentrates and infusions used for scurvy, as well as for therapeutic baths. Pine bud extract has bactericidal properties against staphylococcus, shigella and Escherichia coli. Turpentine is part of the ointments, liniments used for neuralgia, myositis, for rubbing. It is prescribed orally and for inhalation for bronchitis, bronchiectasis. Tar has disinfectant and insecticidal properties, has a local irritant effect. It is used in the form of ointments to treat skin conditions and wounds. The bark contains tannins. Gum from the bark of cedar pine contains turpentine and rosin.

Lactoresins are the milky juices of some plants, close to resins. These include rubber and gutta-percha. Rubber is extracted from the bark of the Hevea brasiliensis tree and is a yellow to dark amorphous mass soluble in carbon disulfide, chloroform, ether and turpentine. Gutta-percha is obtained from some tropical tree species (for example, Isonandra gutta Hook and others). Of the Russian breeds, gutta-percha is contained in the root bark (up to 7%) of the warty and European euonymus. Purified gutta-percha is a brown solid mass, easily soluble in carbon disulfide, chloroform and turpentine. It is used to make cliches for drawings, insulation of electrical cables and more.

Coloring substances can be found both in wood and in the bark, leaves and roots. The wood contains dyes of red, yellow, blue and brown. Of the species growing in our country, for dyeing fabrics and yarn yellow, the local population in the Caucasus uses the wood of maclura, mulberry, skumpia, hornbeam bark, sumac and hop hornbeam, for dyeing red - dry buckthorn bark, brown - skumpia wood , peel walnut and other.

The chemical composition of tree bark differs sharply from the chemical composition of wood (xylem). It should also be noted that the inner and outer parts of the bark, which have different functional purposes and, accordingly, the structure, differ significantly from each other in composition. But quite often, the analysis of the chemical composition of the bark is done without dividing it into bast and crust.

A distinctive feature of the chemical composition of the bark is the high content of extractive substances and the presence of certain specific components that cannot be removed by neutral solvents. By successive extraction with solvents with increasing polarity, from 15 to 55% of its mass is extracted from the bark of different species. The next treatment with a 1% NaOH solution additionally dissolves from 20 to 50% of the mass. As a result of such successive treatments, the tree bark loses from 10 to 75% of its own weight. With all this, not only some of the hemicelluloses are removed from the bark, but also such specific components as suberin and polyphenolic acids of the bark, which cannot be classified as extractive substances. The features of the structure and chemical composition of the bark cause certain difficulties in its analysis and require modification of the methods developed for the analysis of wood, namely, the introduction of additional pretreatments with aqueous and alcoholic solutions and sodium foxide. Otherwise, the presence of suberin and polyphenolic acids can lead to a significant overestimation of the results of the determination of holocellulose and lignin. The bark, when compared with wood, contains more minerals (1.5-5.0)%. Sometimes this is due to the deposition of carbonate crystals in the crust. The ash content of the bark largely depends on the growing conditions of the tree (the composition and moisture content of the soil, etc.).

Mass fraction holocellulose in the bark is approximately two times less than in wood, while its content in the bast is higher than in the bark. Cellulose in the bark, as well as in wood, is the main polysaccharide, but unlike wood, it cannot be called the predominant component of the bark. In the literature, values from 10 to 30% are given for the mass fraction of cellulose in unextracted bark samples.

As in wood, the main hemicelluloses in the bark of coniferous species are glucomannans and xylans, while those of hardwoods are xylans. In the walls of cork cells found glucan - callose. Callose also appears in the phloem as a substance that clogs the sieve plates. Attention is drawn to a rather large mass fraction of uronic acids in the bark, especially in the tissues of the bast, which is associated with a high content of pectin substances. This is consistent with a significantly higher amount of water-soluble polysaccharides in the bark compared to wood. The composition of pectin substances in the bark does not differ significantly from the composition of these substances in wood. Note only a higher content of arabinose.

As already emphasized, one should be cautious about the data available in the literature on the determination of lignin and other components in the bark. For example, for frankincense pine (Pinus taeda), the range of results for determining lignin in the bark is very wide: from 20.4 to 52.2%. The differences may be due to the introduction of different methods of preparing bark samples for analysis and conducting the analysis itself.

Lignin in bark tissues is less evenly distributed than in wood. The outer layer of the crust is more lignified than the inner one. The walls of stony cells are the most lignified. Lignin is also found in the walls of fibers and some types of parenchymal cells of the phloem and crust. The distribution of lignin among different types of cells in the cortex has strong species differences. The lignin of the bark is more condensed than in the wood of the same tree species, which is confirmed to some extent by the data on the delignification of the bark. Bark is more difficult to delignify than wood.

A characteristic component of the outer layer of the bark is suberin, a product of copolycondensation, mainly of higher (C16-C24) saturated and monounsaturated aliphatic a, dicarboxylic acids with hydroxy acids (the latter can be additionally hydroxylated). Participation in the polycondensation of monomers with three or more multifunctional groups (carboxylic, hydroxyl) leads to the formation of a polyester with a network structure. Some researchers admit the existence of simple ether bonds. As a result, suberin cannot be isolated from the bark unchanged, since it cannot be extracted with neutral solvents, and ester bonds make it a very labile component. From the bark, suberin is isolated in the form of suberin monomers after saponification with aqueous or alcoholic solutions of alkali and decomposition of the resulting suberin soap with mineral acid.

Suberin is contained in the periderm, including the wound. It is localized in cork cells, being an integral part of the cell wall. The cork tissue of the cork oak contains (42-46)% suberin, the Brazilian tropical tree paosantha (Kielmeyera coriacea) - 45%, and the cork cells of the warty birch - 45% suberin. The mass fraction of suberin in the outer layer of the bark occasionally exceeds (2-3)%, but there are tree species that are characterized by a high content of suberin. In the above tree species, suberic monomers make up (2-40)% of the mass of the outer part of the bark. characteristic feature The cork tissue of birch - birch bark is the accumulation along with suberin of triterpene alcohol - betulin. The composition of suberic monomers is very diverse. In addition to the dicarboxylic and hydroxy acids mentioned above, the composition of suberic monomers includes monobasic fatty acids, monohydric higher fatty alcohols (up to 20% by weight of suberin), phenolic acids, dilignols (dimers of phenylpropane units) and others.

As already noted, the treatment of bark previously extracted with neutral solvents with a 1% aqueous solution of NaOH extracts up to (15-50)% of the material, which is a group of phenolic substances with acidic properties. This gave reason to call them polyphenolic acids. However, not carboxyl, but carbonyl groups were found in them. After precipitation from an alkaline solution by acidification with mineral acids, polyphenolic acids become partially soluble in water and polar organic solvents. In all likelihood, "polyphenolic acids" are polymeric substances of the flavonoid type, related to condensed tannins and therefore capable of undergoing rearrangement in an alkaline environment with the appearance of carbonyl groups.

Significant differences in the structure and chemical composition of bark and wood necessitate separate processing of these constituent parts wood biomass from both technological and economic points of view. but existing methods removal of bark (barking) is associated with loss of wood. The debarking waste, along with the bark, contains a significant amount of wood, which complicates the chemical processing of such raw materials. The variety of chemical compounds present in the bark makes the idea of extracting the most valuable components attractive. Development this direction bark utilization is constrained by the relatively low content of extractable components. As a result, the main areas of bark processing are still limited to its utilization as an organic material as a fuel, in agriculture etc. Rare examples of the use of the bark of individual tree species for the extraction of tannins, the production of cork, the production of tar (from birch bark) and the isolation of fir balsam from the bark of growing fir trees, unfortunately, do not improve the overall picture of the inefficient use of valuable organic compounds contained in the bark.