MEDICOLEGAL LABORATORY RESEARCHES

From Big Medical Encyclopedia

MEDICOLEGAL LABORATORY RESEARCHES — ways of obtaining the objective data necessary for the solution of the questions arising in expert practice at a research of corpses, material evidences and survey of living persons.

In court. - medical practice the whole complex of laboratory methods of a research — morphological, spectral, radiological, biochemical, etc. is applied, with the help to-rykh such questions, important for examination and the investigation, as establishment of a prizhiznennost and prescription of damages can be solved (see. Damages, in the medicolegal relation ), time of approach of death, the tool of a crime, etc., and also special methods of a research of material evidences (see). Results of researches, both positive, and negative, are subject to careful assessment and comparison to other data, to-rymi the court has. - the medical expert in each case — the results of opening, materials characterizing circumstances of incident, etc.

Gistol. and gistokhy. methods of a research of internals of a corpse allow to specify and objektivizirovat a cause of death, especially in cases of sudden death, to differentiate intravital and postmortem changes, to establish prescription of approach of death, etc. Gistol. also the pieces of fabrics and bodies removed, e.g., from the tool of murder (a knife, the gun) or the vehicle can be subjected to a research. Gistokhim. researches apply for the purpose of establishment of prescription of damages, identification of early stages of development of a myocardial infarction more and more widely (see) and coronary heart disease (see), differentiation of a strangulyatsionny furrow of an intravital origin from posthumous (see. Hanging ), intravital or posthumous developing of burns (see. Burns, in court. - the medical relation ), etc. Reliability of the results of subjects received at the same time big, than material for gistokhy is taken earlier. researches (see. Histologic methods of a research , Histochemical methods of a research , Microscopic methods of a research ).

Cytologic research (see) allows to find cellular elements of the damaged fabrics, sometimes through a long term, on various tools and vehicles, in hyponychial contents and on skin in the field of generative organs of the suspect of a sexual crime etc. The pieces, sufficient in size, found under a stereomicroscope transfer to test tubes of conical shape and fill in with several drops 0,85% of sterile solution of sodium chloride. In 24 hours pieces crush the calcinated microscopic needle to a condition of a suspension, from a part a cut on a slide plate prepare a smear, then dry up it on air, fix in methyl alcohol, paint hematoxylin-eosine and study under a microscope. For identification on various tools or other objects of the isolated cells or their accumulations, make several washouts scrapings. Apply 1 — 2 drops of 0,85% of solution of sodium chloride on the chosen site of a surface of the tool and under control of a stereomicroscope make scraping of the moistened site the microscopic needle or a tip of a scalpel. Washouts scrapings transfer a pasterovsky pipette to pretsipitatsionny test tubes, then the same as is stated above, prepare and investigate smears on slide plates. After detection in drugs of cells and definitions of their fabric origin establish their specific accessory by means of reaction of electroprecipitation in agar gel, reveal group-specific antigens of the AVO isoserological system with the help immunol. reactions of absorption elution and the mixed agglutination, define a sex of cells by a research of a sex chromatin (see). On the basis tsitol. researches of a secret of mammary glands can be established pregnancy and its term, to define the former pregnancy and childbirth, and also the termination by the woman in childbirth of feeding of the child.

An issue spectral analysis (see) allows to find in bodies and blood metals at poisoning with them or their salts, deposits of metal in skin at an electric trauma, and also in sites of the damages caused by metal tools or objects, etc. By means of an issue spectral analysis it is possible to investigate clothes, bodies, fabrics, liquids and allocations of the person, the tool and the objects which had contact with a body of the person, chemical substance, etc., to establish a prizhiznennost of damages, a zhivorozhdennost and a mertvorozh-dennost, prescription of approach of death (6 m. Death in the medicolegal relation) and duration of an antenatal life, time of burial, etc. It is applied also at suspicion on burning of a corpse of the person to identification in sol of calcium, phosphorus, potassium, magnesium and other elements, their quantitative contents and a ratio, e.g. Sa/R, Mg/Na, etc. The method differs in speed, universality, high precision and sensitivity; besides, it allows to register the received results on a photographic plate. Due to the high test-sensitivity observance of requirements to withdrawal and the direction of objects in many respects determine the evidential value of results. The major condition is prevention of additional pollution of material evidences. It is impossible to apply the fixing or preserving liquids to preservation of objects.

X-ray inspection (see) it is used for establishment of the mechanism of an injury on injuries of a skeleton, establishment of a look and features of the damaging tool, and at fire damages — for establishment of existence, localization and a type of a shell, definition of the direction of its movement in a body of the person, location of entrance and output openings of a bullet wound (see. Wounds, wounds ), establishments of a distance of a shot (on injuries of long tubular bones, adjournment of traces of metals on soft tissues at the edges of inlet opening and to other signs). At establishment of age (see) consider features of skeleton structure, in particular existence or lack of the centers of ossification and synostoses. At identification of the personality (see) on roentgenograms of an unknown corpse effects of various diseases or damages can be found.

Laboratory methods of identification of marks of the metals left by the injuring tools on a body and clothes at all types of bruises are very widespread. Depending on a particle size of metal, depth of their penetration and a research objective use various methods of a research or their complex. At the same time impact on a body or clothes of the metal tool and its form, an arrangement of inlet opening at a fire injury can be revealed, distance, with to-rogo the shot, a form of a tokoprovodnik and character of metal is made, from to-rogo it it is made, at an electric trauma (see). Objects of a research are a zone of damages directly on a body and clothes of the person, and also on drugs of a bone and skin. At the same time rags of skin are not recommended to be fixed. Are most widespread at identification of traces of metals chemical methods of a research (a method of chromotypes, a chromatography, staining chemical reactions), identification of metals in soft x-ray emission, a spectral analysis (see). For approximate identification of traces of metal and establishment of their topography use the electron-optical converter or special photography in infrared beams (see. Infrared radiation ). From chemical methods the most universal, revealing not only the nature of metal, but also topography of its adjournment, the method of chromotypes (a contact and diffusion method) is.

It allows to reveal traces of copper, nickel, cobalt, lead, iron, zinc, aluminum. The essence of a method comes down to dissolution of metal on an object of a research in electrolyte, to its transition from the studied object to photographic paper due to diffusion of ions, to identification of metal on paper sensitive qualitative chemical tests under the influence of a reactant developer. The method has several modifications. In the main modification as reactants solvents use: saturated spirit solution rubeanovodorodny to - you for identification of traces of copper, nickel, cobalt, 0,2% water solution of a rodizonat of sodium or potassium (for identification of lead, strontium and barium), and - nitrozo-r-naf-tolite with caustic soda (for identification two-and trivalent iron, zinc, lead, copper), saturated solution of Morin in methyl alcohol (for identification of aluminum). As the trace accepting object (absorbent) apply the usual glossy photographic paper which is previously fixed within 30 min. in 25% solution of sodium thiosulphate, washed out and dried up. At preparation of reactants and washing use a distilled water. Before the research of objects conduct control researches of a subject carrier, the photographic paper and solutions-developers. For ensuring contact of photographic paper and the studied object use various the press.

The research for the purpose of detection of diatomic plankton (see) in blood and internals of a corpse is conducted for diagnosis of drowning (see). Detection of diatomic plankton (shutters of diatomic seaweed — diatoms) in a liver, kidneys, marrow of long tubular bones, and also in the blood taken from a left ventricle and an auricle is a specific diagnostic character of drowning. Before carrying out this research the tools and ware intended for capture of bodies and fabrics shall be washed carefully out by a distilled water. The taken fabrics subject mineralizations (see), besiege the received liquid, centrifuge and investigate a deposit under a microscope. Diagnostic value has detection of a significant amount (tens and hundreds) of shutters of the diatomic seaweed corresponding to structure of diatomic plankton in samples of the water taken from a reservoir in Krom the corpse is found. Detection of diatomic plankton in lungs has no diagnostic value.

For a research of damages on skin of a corpse at putrefactive changes (see. Postmortem changes ) and mummifications (see) use the method developed by A. N. Ratnevsky: rags of skin process acetum-alcohol solution (10 ml ice acetic to - you, 20 ml of 96% of alcohol and a distilled water up to 100 ml). At the same time due to swelling of collagenic fibers of skin, its raspravleniye and recovery of a form of damage many earlier imperceptible details and features of damages come to light.

Researches in ultra-violet and infrared beams use (fluorescence analysis) for establishment of a form of bruises, the nature of pollution by foreign substances and other features invisible at usual lighting (see the Luminescence). So, a research in infrared beams at survey (see) allows to reveal and register a form and the sizes of the latent and hardly noticeable bruises, the drawing of a remote tattoo on the remains of dye in deep layers of skin, existence, a form and the sizes of the foreign bodys absorbing infrared radiation located in deep layers actually of skin (impregnation by metals, grains of gunpowder, etc.)*. At a research of a corpse it is possible to establish the nature, a configuration and features of various damages which are filled in with a thin coat of blood, at a research of material evidences — an arrangement and a form of adjournment of accessory factors of a shot and explosion on dark fabrics of clothes and around the damages covered with blood where they are indiscernible at usual lighting, a form of pollution of articles of clothing various substances absorbing infrared radiation, napr, waste oils from details of vehicles, etc. Fluorescence analysis (see. Luminescence ) allows to establish on character and degree of a luminescence a form and the sizes of hypodermic hemorrhages after disappearance of their visible manifestations due to clearing of own luminescence of skin with hemoglobin of blood, a form of the burns which were earlier on smaller intensity of a luminescence of the skin recovered after healing, prescription of skin hems on color of their luminescence, approximate age of the dead on character and color of a luminescence of cartilaginous tissue, etc.

At a research of a corpse and material evidences apply also various court. - medical tests. E.g., for the purpose of definition of blood in spots use a mikrospektral-ny research (see Mikrospektr the aljny analysis) by means of a microspectroscope (a special nozzle to a microscope) and microcrystallic reactions. Influencing certain reactants blood, receive derivatives of hemoglobin (hemochromogen or haematoporphyrin) and investigate their absorption spectrums. Microcrystallic reactions are based on property of nek-ry derivatives of hemoglobin (see) to form characteristic crystals. They are less sensitive, than a mikrospekt-ralny research, and in a crust, time lost the value. Preliminary chemical assays have a certain value in recognition of poisoning with carbon monoxide (see) and for confirmation of absence in an organism of the osvidetelstvuyemy person of ethyl alcohol (see Alcohol). Apply so-called vital tests to definition of a zhivorozh-dennost (see) — pulmonary and gastrointestinal. Pulmonary test is based on change of density and specific weight of the breathing lungs. Gastrointestinal — that the breathing baby has a stomach and guts owing to hit in them the swallowed air gain ability to float in water.

In practice court. - medical examinations apply separate biochemical and serological researches (see). So, at diagnosis of death from the general cooling of an organism, acute coronary insufficiency make determination of content of carbohydrates in a liver by means of various biochemical methods of a research.

For diagnosis inf. the diseases which were the reason of sudden death apply methods immunofluorescence (see), hl. obr. at deaths door children from acute respiratory viral diseases, and also various virologic and bacteriological methods of a research.

Laboratory researches are widely applied at examination of material evidences biol. origins for their identification as object, establishment of specific, group accessory, etc. (see. Blood , Urine , Sweat , Saliva , Sperm ).



Bibliography: Barsegyants L. O. and Levchenkov B. D. Forensic medical examination of allocations of an organism, M., 1978; S. A. Drills and M e shch e republics and V. I. Mikrorentgenografiya's N of biological objects, Saratov, 1977; Drills S. A. and Reznikov of B. D. Rentgenologiya in forensic medicine, Saratov, 1975; Laboratory and special methods of a research in forensic medicine, under the editorship of V. I. Pashkova and V. V. Tomilin, M., 1975, bibliogr.; Naumenko V. G. and Mityaev N. A. Histologic and cytologic methods of a research in forensic medicine, M., 1980; Resinous woods N and N about in V. M., Sh and r and N with to and y P. P. and Pashinyan G. A. Medicolegal diagnosis of a zhivorozhdennost, M., 1974; T about m and l and V. V. N and of l and recreation center and x A. S. A medicolegal blood analysis in cases of a doubtful paternity, motherhood and replacement of children, M., 1981; Tumanov A. K. Bases of forensic medical examination of material evidences, M., 1975.


V. V. Tomilin, P. P. Shirineky.

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