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Biomedical subjects

D G Dimitrov

Publications and source records attributed to D G Dimitrov.

9 recordsLinked to original sources
PubMed1996

Effects of products of activated immune cells and recombinant cytokines on spontaneous and ionophore-induced acrosome reaction.

PROBLEM: The purpose of this study was to examine whether the products of activated immune cells influence spontaneous and ionophore-induced sperm acrosome reaction. METHOD: The spontaneous and ionophore-induced acrosome reaction were evaluated by staining with fluorescein isothiocyanate (FITC) Pisum sativam agglutinin after incubation in capacitating media supplemented with either supernatants from Con-A activated leukocyte cultures or human recombinant (r) IL-1 beta, TNF-alpha, and INF-gamma. RESULTS: The supernatants from Con A-activated peripheral blood leukocyte cultures at 1:1 and 1:10 dilution significantly increased the rate of spontaneous acrosome reaction (P < 0.001 and P < 0.01). Along with displayed abnormally elevated levels of spontaneous acrosome loss, sperm cells showed an insufficient ability to undergo acrosome reaction in response to the ionophore treatment. Recombinant IL-1 beta at increasing concentrations from 30 to 3 x 10(4) U/ml did not have an effect on spontaneous and ionophore-induced acrosome reaction. In contrast, spermatozoa that underwent capacitation in media with 7 x 10(3), 7 x 10(4), and 7 x 10(5) U/ml of rINF-gamma showed a significant increase in spontaneous and induced acrosome reaction compared to the control (P < 0.001). Recombinant TNF-alpha at concentrations of 3.5 x 10(3) U/ml and 3.5 x 10(4) U/ml significantly inhibited ionophore-induced acrosome reaction (P < 0.001). Both rINF-gamma and rTNF-alpha together revealed an effect on the acrosome reaction similar to Con-A generated supernatants (1:1 and 1:10 dilution) only at the highest concentrations. CONCLUSIONS: Some cases of infertility may result from a defective acrosome reaction (premature acrosome loss or insufficient acrosome response to the stimulants) caused by products of activated lymphocytes and macrophages that are released into the male and female reproductive tracts.

Acrosome↗
PubMed1996

Quantitative changes in macrophage distribution in normal mouse ovary over the course of the estrous cycle examined with an image analysis system.

PROBLEM: The current study considered the distribution of macrophages within the major ovarian structures throughout the estrous cycle. METHODS: Immunohistochemical analyses were carried out using an avidin-biotin-peroxidase staining method and the rat anti-mouse macrophage monoclonal antibody anti-Mac-l was applied to stain macrophages. A computer-assisted image analysis system was used to quantify and compare the distribution of macrophages within individual ovarian structures during the estrous cycle. The following morphological structures were analyzed: primordial, preantral, antral, pre-Graafian, and atretic follicles; first-, second-, and third-generation corpora lutea; and the interstitium. The analysis included follicular and corpus luteum substructures: theca, granulosa cells, and interstitium. The system allows the estimation of macrophage distribution as a macrophage density per microns2 of the defined area. RESULTS: Primordial and preantral follicles did not contain macrophages during all stages of the estrous cycle. In antral, pre-graafian, and graafian follicles, macrophages were located and quantified only in the theca and were not detected in the granulosa cell layer. In contrast, atretic follicles showed macrophage localization in both thecal and granulosa cell layers. Macrophages were present in small numbers in the granulosa luteal cell layer and in high numbers in the thecal layer of newly developing corpora lutea. In the second generation of corpus luteum, macrophages followed the same pattern of distribution, while old corpora lutea contained significantly higher numbers of macrophages in both thecal and luteal cell layers. Surprisingly, significant quantitative changes in the macrophages distribution were detected over the course of the estrous cycle. Macrophage density was significantly higher in proestrus and metestrus when compared with the density in diestrus and estrus in most of the studied substructures with the exception of atretic follicles. Atretic follicles showed high macrophage density throughout the cycle with a two-fold higher density at metestrus. CONCLUSION: Macrophages were present in the mouse ovary over the course of the estrous cycle. The greatest numbers of macrophages appearing in corpora lutea and in atretic follicles suggest a role for macrophages in corpus luteum differentiation and follicular atresia. Their patterns of distribution at proestrus and metestrus within microenvironmental compartments suggests a functional correlation with the events of ovarian development.

Animals↗
PubMed1994

Correlation of asthenozoospermia with increased antisperm cell-mediated immunity in men from infertile couples.

To investigate whether cell-mediated immunity (CMI) against sperm and/or antisperm circulating antibodies are associated with poor semen quality, a leukocyte migration inhibition factor (LMIF) assay and an enzyme-linked immunosorbent assay (ELISA) were performed in groups of men from infertile couples, men from fertile couples and sperm donors. Twenty-five of 102 men (25%) revealed positive CMI against sperm and 10 (10%) had positive antisperm antibody titers in their sera. Fifteen of 28 asthenozoospermic men (53%) from infertile couples revealed positive antisperm CMI. The incidence of antisperm CMI was significantly increased (P < 0.05) in the infertile men with asthenozoospermia compared with the men from the other two groups (men from fertile couples and sperm donors). No significant differences between migration indices were seen when such a comparison was done for oligoasthenoterato- and teratozoospermics. The results indicate that increased antisperm CMI is associated with asthenozoospermia in a significant number of men from infertile couples. The importance of these findings is discussed.

Autoantibodies↗
PubMed1992

A quantitative objective method for the evaluation of anti-sperm cell-mediated immunity in humans.

Anti-sperm cell-mediated immunity (CMI) is considered as a crucial facet of infertility in patients of both sexes. A precise and objective method is designed, based on a one-step agarose leukocyte migration inhibition factor (LMIF) assay. The migration areas are evaluated by a computer-assisted image analysis system. Optimal concentrations of leukocytes and sperm, as well as technical conditions are described. The radial migration indexes (RMI) and area migration indexes (AMI) are computed and expressed as a migration index (MI) percentage for each patient or control. Preliminary clinical results indicate a highly significant association between migration inhibition and cases of 'immunopathological infertility'. The method described is considered a promising tool for a rapid and quantitative evaluation of a suspected anti-sperm CMI in infertile and recurrently aborting patients.

Autoimmunity↗
PubMed1992

[Cell-mediated immune reactivity to sperm in disorders of human reproduction].

Besides the pathological anti-sperm humoral immunity, pathological anti-sperm cell-mediated immunity is considered as a crucial facet of the disturbances of human reproduction (male and female infertility, recurrent abortions, endometriosis, late EPH gestosis, fetal hypotrophy). A precise and objective method is designed, based on a one-step agarose Leukocyte Migration Inhibition Factor assay. The migration areas are evaluated by a computer-assisted image analysis system. Optimal concentrations of leukocytes and sperm, as well as technical conditions are described. The Radius Migration Indexes and Area Migration Indexes are computed and expressed as a Migration Index percentage for each patient or control. Preliminary clinical results indicate a highly significant association between leukocyte migration inhibition and cases of "immunopathological" infertility and repeated fetal loss.

Cell Migration Inhibition↗
PubMed1991

[A method of determining glucose oxidase-immobilized glucose].

A method for manual measurement of glucose in biologic fluids has been developed, making use of glucose oxidase immobilized on a carbamide derivative of microcrystal cellulose; two variants are suggested: a rapid and a routine one. The method is characterized by a high analytical reliability, its results are in high correlation with the results of measurements by Beckman glucose analyzer (r = 0.92, p less than 0.001). The method is economic (glucose oxidase reagent may be used for more than 300 times), easily available, and is 3 to 6 times more rapid than the method with soluble glucose oxidase. It is particularly convenient for urgent laboratory diagnosis.

Blood Glucose↗
PubMed1990

[A method for determining urea by using immobilized urease].

An available method was developed for manual measurements of urea in biological fluids with the use of urease immobilized in sepharose gel. The suggested technique is more reagent-saving (the same reagent may be used for up to 500 times), 3-6-fold more rapid, and twice more sensitive than the routine phenolhypochlorite method with soluble urease. The method is characterized by a high analytical reliability, its results are in high correlation with the soluble urease procedure and with the diacetylmonoxime method (r = 07988 and 0.995, respectively). It is particularly fit for rapid analysis of the urea and convenient for small laboratories.

Enzymes, Immobilized↗
PubMedDate not supplied

[Resistance to +Gz and +Gx loads of subjects in older age groups, healthy and with initial signs of atherosclerosis].

Tolerance to +Gz and +Gx acceleration of healthy and atherosclerotic subjects, aged 40-49, was investigated during 256 centrifugation tests in Bulgaria and the USSR. As compared to the healthy people, the atherosclerotic subjects showed a lower tolerance: when exposed to 7 +Gz the tolerance threshold decreased from 5.93 +/- 0.57 g to 5.7 +/- 0.44 g (i. e. by 0.23 g). Visual disorders in the healthy and atherosclerotic subjects were recorded in 29 and 50%, respectively, and loss of consciousness in 9.56 and 15.15%, respectively (Bulgarian data). When exposed to 5 +Gz and 6 +Gx no subjects displayed visual disorders or loss of consciousness (Soviet data). However, lower tolerance of 5 +Gz due to cardiac arrhythmias was observed in 4.8% atherosclerotic patients and in none healthy subjects. Lower tolerance to 6 +Gx associated with cardiac arrhythmias was recorder in 23.8% atherosclerotic versus 11.8% healthy subjects (i. e. 12% more). Nevertheless, in most subjects, both healthy and atherosclerotic, acceleration tolerance was good. These findings indicate that individual assessment of acceleration tolerance is of great importance for people older than 40 years with health abnormalities.

Acceleration↗