Laboratornoe delo最新文献

The authors suggest an unsophisticated approach to laboratory diagnosis of spongiform encephalopathies induced by unconventional prion viruses, consisting in electron microscopic detection of abnormal helical Scrapie-associated fibrils. These fibrils are detectable in human and animal brain tissue samples and in cell cultures.

Antibodies to three mycobacterial antigens, Soviet tuberculin and ultrasound-treated Mycobacterium tuberculosis (H37Rv) and M. bovis (BCG) were detected by enzyme immunoassay in 90 patients with pulmonary tuberculosis and 75 normal subjects. Antibody detection rates and levels were found related to the form of tuberculous process. The detection rate was rather low in focal tuberculosis and virtually the same for all the antigens (15.3 percent). In disseminated processes (infiltrative and particularly disseminated and fibrous-cavernous) antibodies are detected more often in higher titers than in local processes, and their levels are different with different antigens. The method was more sensitive with ultrasound-treated antigens of M. tuberculosis (H37RV) and M. bovis (BCG) than with PPD. Simultaneous enzyme immunoassay with three antigens detected up to 75 percent of antituberculous antibodies in infiltrative, up to 92 percent of antibodies in disseminated, and up to 100 percent of antibodies in fibrous-cavernous tuberculosis.

A method for estimating the net cost of biochemical investigations has been developed as exemplified by the clinical laboratory of the N. N. Petrov Research Institute of Oncology of the USSR Ministry of Health. A data bank including information on the wages fund, cost of material used, equipment wear, and other expenditures was created for these estimations. Labor consumption for each of the 27 types of biochemical investigations comprised the production time of physicians (79.3 percent) and laboratory assistants (87.3 percent). Net cost of physicians' productive minute has made up 0.04 roubles, that of laboratory assistants' minute, 0.02 roubles. Wastes unrelated to the time of investigation were also taken into consideration.

A cell scintillator intended for analysis of the disperse composition and concentration of poor contrast biologic objects suspended in transparent liquid media has been designed at the Analitpribor Research and Production Amalgamation in Tbilisi for the Cytology Institute of the USSR Academy of Sciences in Leningrad. The apparatus is based on light blocking and hydro-focussing physical principles. Automated system of the apparatus calibration permits measurements of the particles 3 to 150 microns in size at the level of 10%. The mean error of cell concentration estimation within the range of 10000-150000 cell/ml is 3%.

The authors suggest a simple and convenient procedure for measuring acute-phase proteins, lactoferrin, fibrinogen and its degradation products, in mixed human saliva by the agar immunodiffusion test with appropriate monospecific antisera. Examinations of 1205 salivary samples have revealed that salivary fibrinogen degradation products and lactoferrin detection rates do not depend on the subject's sex but are growing with age and intensity of the aggressive admixture effects in inhaled air; they are also related to the intensity of the inflammatory and proliferative processes in the oral cavity and bronchopulmonary system, the values varying from 4-16 percent in health to 68.8-71.8 percent in disease. In monitoring salivary acute-phase proteins detection rates make up 100 percent in the patients and 0-4 percent in normal subjects. The authors come to a conclusion that measurements of salivary acute-phase proteins may be used in screening of the population to detect subjects at risk for further diagnostic examinations.

Adhesive characteristics of the sputum are assessed from adhesion to glass. The force and time of preliminary pressure on the tested material are not taken into consideration, nor is the rate of augmentation of the force directed to disruption of the adhesion contact. The strength of the adhesion contact was found directly depending on the force and time of preliminary pressure and inversely related to disrupting force augmentation rate. A conclusion is made on the necessity of stabilizing work schedules (in reference to the above parameters) for the standardization of the method.

A method for qualitative assessment of glucose-6-phosphate dehydrogenase in Yersinia is suggested. The reaction mixture was prepared by mixing the ingredients in the ratios as follows: 10 microliters of 0.01 M glucose-6-phosphate, 10 microliters of 0.0075 M NADP, 30 microliters of 0.75 M tris HCl pH 7.8, 10 microliters of 0.2 M MgCl2, 20 microliters of distilled water. The reaction was triggered by adding 20 microliters of cell-free bacterial extract. After 110-130 min incubation 10-20 microliters aliquots w re collected on filter paper (Whatman No 1) strips. The stains were dried at ambient temperature and examined in UV light at 365 nm with the use of a routine UV lamp. This method shows intensive fluorescence of the stain in M. tuberculosis and very poor fluorescence in Y. pestis. This technique is convenient when the scope of identification tests and differentiation between these two agents is high.

Red cell aldehyde dehydrogenase (ALDH, EC 1.2.1.3) activity was measured by spectrophotometry in normal subjects and alcoholics after various periods of alcohol abstinence. ALDH was measured in all red cell hemolysate fractions; red cells were purified from hemoglobin by Sephadex CM-50 chromatography. The enzyme activity was found reduced in alcoholics' red cells as against that in controls. ALDH activities were somewhat increasing and approaching the normal values in the patients not using ethanol for 4 weeks or longer. These results recommend ALDH measurements in human red cells as a test for the detection of subjects abusing alcohol.