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Taking material for histological, cytological and other types of research



Histological, cytological and other types of studies are an important diagnostic stage in the study of a corpse, especially in the presence of infectious diseases.

From pathologically altered organs (tubercles, nodes, ulcers, abscesses, scars, etc.), pieces of tissue are excised (making imprints on glass slides if necessary), capturing neighboring, unchanged or normal areas. Pieces should not be thicker than 0.5 cm, other sizes depend on the lesion (usually excise an object no larger than 2x1 cm). Pieces are usually fixed in a 10% formalin solution, better than neutral. A piece of gauze is placed at the bottom of the vessel, the volume of the fixative must exceed 5–7 times the volume of objects, the duration of fixation is 1-2 days; then comes dehydration and pouring a piece into a dense medium [Weil S.S., 1947; Romeis B., 1953; Roskin G.N., Levinson L.B., 1957; Avtandilov G.G., 1961; Pierce E., 1962; Merkulov G.A., 1969; Lilly R., 1969, and others.].

Depending on the nature of the pathological changes, the nosological unit and the cause of death, the number of pieces excised from the organs of the corpse varies. Typically, 10-15 pieces are examined, but in cases where an in-depth histological examination is required for diagnostic purposes, it is not necessary to limit the amount of material taken. We have developed [Avtandilov G.G. et al., 1976] recommendations on the number of pieces of various organs necessary for histological examination in the most common diseases (Appendix 6). At the same time, a set of histological stains of sections was determined and a technique for their implementation by a laboratory assistant, giving the most information about the pathological process under study. These recommendations are given in appendices 7, 8. The procedure for conducting other additional studies (bacterioscopic, bacteriological, virological, etc.) is presented in the following chapters.

Note the importance for the diagnosis of neuropsychiatric diseases of the histological examination of sectional material. During the autopsy, sites are taken from the frontal, parietal and temporal lobes, the region of the central gyrus, from the subcortical nodes of the brain, the optic tubercles with the wall of the third ventricle of the brain, the hypothalamic region, the pons, the medulla oblongata and cerebellum. Additionally, the vascular plexuses of the lateral ventricles and their ependyma are examined.

A piece is cut from the temporal lobe together with the site of the ammonian horn, from the occipital lobe - at the level of the spur fissure, from the parietal - in the region of the parietal lobe.

Only two pieces can be excised from the subcortical region: one should cover the region of the shell, capsule and part of the pale ball, the second is taken at the level of the optic tubercle and the subthumb with the wall of the third ventricle of the brain. A piece is removed from the cerebellum, capturing its cortex and the dentate nucleus, from the medulla oblongata - the level of the lower olives. In case of indications, various segments of the spinal cord are excised for histological examination. Of the recommended histological techniques, in addition to staining with hematoxylin and eosin. Nissl’s technique is considered the main color of nerve tissue. The material is kept in a 10% formalin solution for no more than a day (then comes the alcohol battery). Additionally, a complex of neurohistological techniques is used in Appendix 7, 8).

In pathological autopsy, in some cases it is necessary to make blood smears for hematological analysis (blood is taken from the femoral vein or cavity of the heart).

For biochemical analysis of cadaveric blood it is proposed to use standard laboratory research methods used in clinical practice, which makes it possible to compare the results of clinical and post-mortem blood tests [Permyakov N.K. et al., 1983].

Cadaveric blood is examined by the following methods: potassium and sodium of plasma and red blood cells using flame photometry, calcium using the Clark method, sugar using the Hagedorn and Enssen methods, residual nitrogen using the Rappoport method, urea using the hypobromite method, free ammonia using the isothermal distillation method, and free hemoglobin - spectrophotometrically according to hydrochloric acid hematin, total bilirubin - according to Endrashik, Klegorn and Govu. the amount of total protein - according to the Lowry method, the percentage of protein fractions - by electrophoresis on paper, the pH value is measured by a potentiometer.

The most convenient source for blood sampling both during autopsy and before it is the femoral vein. Blood must be taken from the corpse in the first 24 hours after death and examined within the first hour after capture. Blood sampling at a later date than a day after death is undesirable, since by this time autolysis processes are developing in it, the effect of which on biochemical parameters is difficult to take into account. If it is impossible to perform the analysis immediately after blood sampling, it can be stored in the refrigerator at a temperature of plus 4-8 ° C for 2-3 days. Shelf life in the refrigerator can be extended up to a week if cadaveric blood is sterilized. For biochemical analyzes in the volume indicated above, 10 ml (1 tube) of blood is enough.

It is customary to distinguish between liquid blood, characteristic of the sudden death of any etiology and denoted in the literature by the term "fibrinolysis blood" and the blood of patients who died in a state of agony, which is called postagonal blood (Table 11). When examining the fibrinolysis and postagonal blood of people who have died from cardiovascular diseases, as well as from any other reasons, it is necessary to take into account the time of its removal from the corpse. Unlike donor blood in cadaveric blood, the magnitude of biochemical parameters varies significantly depending on the time elapsed after death.

Table Biochemical parameters of fibrinolysis and postagonal blood (M ± m) [Permyakov N.K. et al., 1983] 1 Translation into SI units by us

Object of study Fibrinolysis blood, time taken, h Postagonal
0-6 6-12 12-24,
In mg% and mmol / L
Potassium: in plasma 47.3 ± 4.4 12.1 ± 1.1 72.4 ± 4.7 18.4 ± 1.2 102 ± 6.4 26.1 ± 1.6 104 ± 11.6 35.8 ± 2.9
in red blood cells 318 ± 6 81.4 ± 1.5 321 ± 9.3 82.2 ± 2.3 319 ± 4.2 81.7 ± 1.1 305 ± 7.3 78 ± 1.7
Sodium: in plasma 306 ± 4.5 133.1 ± 1.9 349 ± 7 151.8 ± 3 320 ± 5.3 139.2 ± 2.3 303 ± 7.8 131.8 ± 3.4
in red blood cells 49.4 ± 3.7 21.5 ± 1.6 54 ± 1.9 23.5 ± 0.8 62 ± 2.3 26.9 ± 1 52.7 ± 3.7 22.9 ± 1.6
Calcium 12.4 ± 0.1, 3.1 ± 0.005 14 ± 0.5 3.5 ± 0.1 14 ± 0.4 3.5 ± 0.09 no data
Glucose no data no data 105 ± 13, 5.3 ± 0.76 47 ± 2.6 2.6 ± 0.14
Residual nitrogen 52.4 ± 1.8 38.7 ± 1.3 60 ± 2 42.8 ± 1.4 77.1 ± 4.4 55 ± 3.1 89 ± 2.5 63.5 ± 1.8
Urea no data no data 81 ± 10.3 13.5 ± 1.7 97.4 ± 12.5 16.2 ± 2.1
In mg% and mmol / l:
Total bilirubin no data no data 0.96 ± 0.02 16.4 ± 0.3 1.1 ± 0.01 18.8 ± 0.1
FS mi and g / i:
Free hemoglobin (after hemolysis) 95.3 ± 12 0.59 ± 0.07 104-19 0.64 ± 0.1 196 ± 11 1.2 ± 0.07 329 ± 2 ± 0.48
In g%, and g / l:
Plasma proteins no data 7.6 ± 0.2 76 ± 2 7.8 ± 0.3 78 ± 3 7.6 ± 0.3 76 ± 3
Postagonal blood of people who died from cardiovascular disease. differs from fibrinolysis by the presence of red and mixed convolutions in the vessels of the corpse, which do not undergo spontaneous lysis. Such blood also differs in a number of biochemical parameters even in the same group of cardiovascular diseases. These changes are associated with the presence in such patients of a long terminal period, during which significant metabolic disturbances and cleansing of the body of accumulated toxins occur, characteristic of the dying period.

In cadaveric blood, in a number of diseases, an increased content of total bilirubin is noted: in case of renal failure - 2 ± 0.9 mg%, in acute pathology of the abdominal organs - 2.5 ± 0.8 mg%, in case of traumatic brain injury - 4.6 ± 2.3 mg%. A slightly increased bilirubin content in the plasma of cadaveric blood in these diseases can be attributed to a decrease in liver function.

When dying from renal failure, the concentration of sodium ions decreases (272 ± 10.7 mg%).
Since cadaveric hyponatremia is observed only in cases of death from renal failure, this parameter can be used by a pathologist as a diagnostic indicator of renal failure.

The most valuable indicator for post-mortem diagnosis of renal failure is the content of residual nitrogen and urea in cadaveric blood. free ammonia. The content of residual nitrogen in cadaveric blood, as poisoned, doubles its intravital amount (before the onset of agony), regardless of the cause of death. So, in patients with cardiovascular diseases, the content of residual nitrogen is within the physiological norm - 20-40 mg%, whereas after death it is 89.0 ± 2.5 mg%. If the main disease is pneumonia or cerebrovascular accident, then during life the content of residual nitrogen in the blood is on average 55.0 ± 3.7 mg%, and after death - 116.0 ± 4.0 mg%; in acute pathology of the abdominal organs, during life - 73.0 ± 12.2 mg%, after death - 141.0 ± 11.2 mg%; with traumatic brain injury, during life - 75.0 ± 9.5 mg%, after death - 138.0 ± 18.1 mg%. However, when comparing intravital and posthumous indicators, it should be remembered that the main accumulation of nitrogenous slag occurs in the pre-agonal and atonal periods. If the blood is examined in the terminal period, then by the content of residual nitrogen it will differ little from the blood of a corpse.

When dying from severe kidney failure that developed after a chronic urological disease or chemical poisoning, cadaveric blood has the highest residual nitrogen content of 229.0 ± 5.23 mg%), while in people suffering from mild to moderate renal failure, deaths from other causes, posthumously determined to be half the residual nitrogen (123.0 ± 5.93 mg%). The residual nitrogen content in the post-mortem blood of people who died from abdominal pathology (141.0 ± 11.2 mg%) and traumatic brain injury (138.0 ± 18.1 mg%) is close to its amount in patients with moderate renal failure and mild severity (123.0 ± 5.93 mg%). Therefore, this degree of azotemia cannot be a criterion of renal failure.

The concentration of residual nitrogen is two times higher than the intravital preagonal content; the highest concentrations of residual nitrogen (200-300 mg%) are observed in cadaveric blood when patients die from renal failure of any etiology.

In severe renal failure, post-mortem urea content inserts 295.3 ± 16.7 mg%, while in mild and moderate renal failure, an average of 143.7 ± 9.1 mg%.

Renal failure is characterized by the highest ammonia content (5.19 ± 0.37 mg%) in cadaveric blood. However, in case of traumatic brain injury, the concentration of free ammonia is also significantly increased (4.79 ± 0.45 mg%). It should be borne in mind that a high content of free ammonia in cadaveric blood can be a consequence of liver damage.

Thus, the indications of residual nitrogen and the concentration of sodium ions in the plasma of cadaveric blood can serve, together with clinical and pathological data, as objective criteria for the degree of renal failure. In the presence of deep dystrophic changes in the kidneys, a high content of residual nitrogen (200-300 mg%) and its components allows one to diagnose renal etiology. However, with prolonged chronic urological disease, the existing morphological implications of the kidneys may not always be adequate to violations of their excretory function. In addition, there are cases when the treatment given to the patient is effective (hemodialysis). In such situations, the content of residual nitrogen in cadaveric blood is a criterion in determining the cause of death. When its content in cadaveric blood is about 120-160 mg%, it is necessary to assume a certain role of azotemia in thanatogenesis, but not to regard it as the main cause of death, despite the presence of certain morphological signs of kidney damage. At the same time, a high content of residual nitrogen, in excess of 200 mg%, in the absence of a specific pathology of the kidneys makes it possible to diagnose acute renal failure. The determination of the residual nitrogen content in cadaveric blood is also very important for the diagnosis of chloriprivic uremia along with the determination of blood chlorides. So, with severe intoxications, as with malignant neoplasms, when the patient has a large loss of fluid, the presence of a high content of residual nitrogen (200-300 mg%) with a reduced amount of chlorides speaks for chloriprivic uremia, which can be diagnosed as a competing disease.

The level of sugar concentration in cadaveric blood can serve as a well-known help in establishing the diagnosis of diabetes mellitus and especially hyperglycemic coma.

In the blood of sudden deaths, the average sugar content is 105 ± 13.8 mg%. If patients with cardiovascular diseases die after prolonged agony, then by the end of the first day after death their blood contains half as much sugar as suddenly died (47.0 mg%). The more time passes since death, the lower the concentration of sugar in cadaveric blood.

Hyperglycemia, corresponding to intravital indicators, is noted only in those cases when glucose solution is administered intravenously to patients in the terminal period. In this case, cadaveric sugar reaches 300-500 mg% without any clinical and morphological signs of diabetes. In all other cases, post-mortem indicators are characterized by hypoglycemia, the degree of which depends on the time spent in the vessels of the corpse.

When barbiturate poisoning is most often observed high (200-300 mg%) sugar content in cadaveric blood, which is associated with glucose therapy of such patients in a coma.

Thus, the sugar content in cadaveric blood taken from the femoral vein on the first day after death is in the range of 40-60 mg%. At higher concentrations, the introduction of glucose solutions in the atonal period should be excluded.

The cadaveric sugar content in patients with mild and moderate diabetes mellitus, which was not the main cause of death, averages 54.0 ± 3.6 mg%. At the same time, the sugar content in cadaveric blood taken during the first day from the femoral vein is almost three times less than its intravital concentration and coincides with the control standards for postagonal blood.

In severe diabetes mellitus, a higher sugar content in cadaveric blood is determined - 232.0 ± 19 mg%. Cadaveric blood in severe diabetes mellitus also contains 1.5 times less sugar than in life, but the absolute values ​​are much higher than the cadaveric blood sugar content of those who died from other causes or diabetes mellitus.

In practice, there are cases when there is a low sugar content in cadaveric blood, despite the presence of a severe form of diabetes. Such a low sugar content (63.0 ± 7.2 mg.%) Is associated with intensive insulin therapy before death. In cases of an insulin-resistant form of diabetes mellitus and if insulin is not administered before death, a high concentration of sugar in cadaveric blood remains (232.0 ± 18.9 mg%).

The high sugar content in cadaveric blood is retained even in cases when blood taken from the femoral vein during the first days after the death of the patient is examined after 2-3 days of storage in a refrigerator at a temperature of + 4-8 ° С.

In the case of hyperglycemic coma, from which the patient cannot be withdrawn by therapeutic measures, the sugar content in cadaveric blood reaches particularly high values ​​(600-900 mg%).

Thus, analysis of cadaveric blood for sugar content may be useful in the following options:

1) to establish severe diabetes mellitus, taking into account the measures taken;

2) to establish hyperglycemic coma by the presence of a high concentration of sugar (400-500 mg% and above);

3) to establish the nature of dying (sudden death, agony), since the content of sugar in postagonal blood is reduced by 2 times compared with fibrinolysis.

Naturally, postgonal blood hypoglycemia appears to be an obstacle to the diagnosis of hypoglycemic coma. When discussing the results of a biochemical analysis of cadaveric blood for sugar, it is necessary to take into account the therapeutic measures carried out in the terminal period (insulin therapy, transfusion of glucose solutions).

Methods of taking material for other types of research, including forensic medicine, are given in subsequent chapters. The staff of the pathological department should know that any material removed from the corpse can become the object of a forensic medical examination, being material evidence.

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Taking material for histological, cytological and other types of research

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    In many cases, changes in organs, detection - with a macroscopic examination, are so insignificant that they do not allow the doctor to draw conclusions about the nature of the pathological process and the cause of death. In this regard, there is a need for microscopic examination of internal organs, especially the lungs. The material for histological examination is placed in a glass jar with
  2. Taking material for laboratory research
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  4. Taking material for research
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  5. Microbiological material collection
    In cases where it is suspected that death came from an infectious disease, it is necessary to take material for microbiological research. The sequence of opening the cavities and organs of the corpse in such cases varies somewhat: the section begins with those areas of the body where the material should be taken to avoid contamination of the section field and remove the material in the most sterile
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