Search PubMed⌕ Search

Biomedical subjects

M Petrov

Publications and source records attributed to M Petrov.

At least 19 recordsLinked to original sources
PubMed2005

Surveillance of antimicrobial resistance in Bulgaria--a synopsis from BulSTAR 2003.

We introduce Bulgarian Surveillance Tracking Antimicrobial Resistance (BulSTAR) and make the first report on surveillance data for 2003. This longitudinal surveillance programme monitors the isolation and antimicrobial susceptibility of all clinically significant microorganisms isolated from blood cultures, cerebrospinal fluid, upper and lower respiratory tract, urine and wound samples in the participating microbiology laboratories. Twenty eight public, 45 hospital and 6 private laboratories from all 28 counties of the Republic of Bulgaria participated in BulSTAR 2003. The total number of isolates from monitored sources during the surveillance period was 98 929. Seven microorganisms represented 72% of all isolated bacteria in BulSTAR 2003: Escherichia coli, Staphylococcus aureus, Proteus-Providencia-Morganella group, Klebsiella spp., Pseudomonas spp, Streptococcus pneumoniae and Streptococcus pyogenes. Generally the resistance of clinically significant Gram positive and Gram negative bacteria in Bulgaria was estimated to be at a medium level when compared with many other surveillance sources worldwide. A unique 32-year experiment on the population by treating all severe infections with an ampicillin/gentamicin combination resulted in twofold higher levels of resistance to amynoglycosides compared with other countries worldwide. This is due to the extremely conservative treatment schemes used in the former socialist countries, based on national directives and cheap domestic production of gentamicin and ampicillin. The forthcoming introduction of a computer network and improvements in detecting mistakes are expected to increase the sensitivity and the significance of BulSTAR surveillance system - an indispensable tool in the combat against increasing worldwide antibiotic resistance.

Anti-Bacterial Agents↗
PubMed1999

Effect of cryopreservation of zona-binding capacity of canine spermatozoa in vitro.

The hemizona assay (HZA) was used as a functional test for zona pellucida binding capacity of fresh and frozen-thawed canine spermatozoa. We investigated 30 ejaculates from 3 dogs with sperm motility > 70% and sperm concentration > 5.10(8) cells per ejaculate with up to 20% abnormal and dead spermatozoa. Fifteen ejaculates were each divided into 2 portions: one portion was used for analysis of fresh semen, the other for cryopreserved semen. On the day of the experiments, in vitro-matured canine oocytes were bisected into 2 equal hemizonae. One half of the hemizonae were coincubated with fresh capacitated (control) spermatozoa, the other half of the hemizonae were coincubated with frozen-thawed (tested) spermatozoa at final concentration of 1 to 2 x 10(6) cells/mL in 200 microL droplets of BSA-supplemented Toyoda, Yokojama and Hoshi (TYH) medium at 37 degrees C, 5%, CO2 for 1 h. Sperm suspensions were examined kinesigraphically for post capacitation type of movement. The Student's t-test was used to compare differences between semen parameters. The data on HZA binding activity of fresh and frozen-thawed canine semen were analyzed by ANOVA and then by the Newman-Keuls multiple range method. The results showed no differences in the initial semen quality parameters among the 3 dogs. After thawing, the semen from Dog 1 and Dog 2 demonstrated relatively uniform sperm parameters, while in Dog 3 sperm motility, and viability and the percentage of morphologically normal spermatozoa were significantly decreased. The binding activity of frozen-thawed spermatozoa from the 3 dogs was significantly reduced (29.40 +/- 9.02, 18.60 +/- 3.30, 8.20 +/- 4.49) compared with that (107.20 +/- 19.22, 109.80 +/- 20.75, 78.20 +/- 12.47; P < 0.01) of fresh spermatozoa. The results showed that semen samples with similar sperm parameters prior to cryopreservation displayed different sperm zona-binding capacity after freezing. The HZI (value of sperm binding capacity of frozen-thawed vs fresh semen samples) was higher in Dog 1 (27.43) than in Dog 2 (16.90) or Dog 3 (10.40), and thus confirmed the variation of zona binding activity after thawing between dogs. The freezability of individual dog semen is discussed. In conclusion HZA may be a valuable tool for evaluating the post-thaw fertilizing ability of canine spermatozoa.

Animals↗
PubMed1999

Zona pellucida autoantibodies in women undergoing ART.

The presence of ZP autoantibodies in serum and Ffl samples of 109 women attending the ART Center in Kiev was investigated using IIF and ELISA. Positive serum and Ffl samples examined by both methods were found in 20 (18.34%) and in 19 (17.43%) patients respectively; 31 (28.44%) serum samples and 33 (30.27 %) Ffl samples analyzed by IIF were positive; of the samples analyzed by ELISA 21 (19.26%) and 20 (18.34%), respectively, were positive. No relationship was found between ZP autoantibody incidence and the type and cause of infertility. A significant prevalence of ZP autoantibodies detected by ELISA in Ffl was found in patients with fertilization failure (39.13%) and with low fertilization rate (42.85%) when compared to patients with middle fertilization rate (5.71%) and high fertilization rate (8.1%). The clinical significance of ZP autoantibodies in Ffls for in vitro fertilization outcome was suggested.

Adult↗
PubMed1997

Knowledge-based in vivo analysis of kidney concretions from digitized X-rays.

To make a right choice of a treatment approach in patients with nephrolithiasis it is very important for the clinicians to know the composition and structure of calculus. Conventional radiographic techniques and computerized tomography (CT) give information about the location and size of concretions, but not for their composition and structure. In the present study we investigated the gray-level values of chemical substances in concretions. It was established the appropriate X-ray exposure for subsequent image analysis. A method for intracorporal analysis of composition and structure of kidney concretions is proposed.

Artificial Intelligence↗
PubMed1995

Contraceptive potential of porcine zona pellucida in cats.

The contraceptive potential of solubilized porcine zona pellucida (spZP) was studied in 2 groups of cats after active immunization using slightly different protocols. Cats from Group 1 (n = 3) were immunized with a total of 300 8g spZP divided in 4 s.c. multisite injections (each of 37.5 8g) given at 10 day intervals followed by a booster 150 days after the initial immunization. Cats from Group 2 (n = 5) were immunized with a total of 400 8g spZP divided in 4 i.m. injections (each of 50 8g) given at 2 wk intervals followed by a booster 92 days after initial immunization. Immunogen was emulsified in Complete Freund Adjuvant for the first dose and in Incomplete Freund Adjuvant for the following 3 doses. The respective controls were immunized in the same manner using only adjuvant and PBS. Immunofluorescence studies showed intense fluorescence on the zona pellucida (ZP) of the oocytes isolated from immunized cats, as well as on the ZP of porcine and cat oocytes preincubated in immune sera. Sera from cats immunized with spZP inhibited in vitro binding was demonstrated in oocytes isolated from immunized group 1 cats. In vivo fertility data in Group 2 cats revealed that only 1 of 5 cats became pregnant, the one with the lowest anti-spZP titer. The results from the experiments reported above, suggest that in this preliminary study spZP can elicit antibodies with contraceptive potential in actively immunized female cats.

Journal Article↗
PubMed1994

A new surgical approach to internal genitalia in water buffalo (Bubalus bubalis): a preliminary study.

New surgical access to internal genitalia through either the left or right lateral wall of the pelvic cavity was sought in 3 multiparous buffalo cows. (MurrahxMediterranean buffalo crossbreed). An incision 12 to 13 cm long was made in the dorso-caudal part of the regio glutea, equidistant from the tuber ischiadicum and the most prominent point of the crista sacralis mediana (in the space confined dorsally by the caudal part of os sacrum and first 2 to 3 vertebrae coccygeae and ventrally by the spina ischiadica of os ischii), just at the site where the lateral wall of the pelvic cavity is thinnest. Ovaries, oviducts and uterine horns were successfully exteriorized through this glutea approach in all 3 animals.

Journal Article↗
PubMed1993

Intermediate filaments and ATPase activity in the vascular wall of vertebrates.

The vascular wall of aorta and vena cava was examined for adenosine triphosphatase (ATPase) activity and cytoskeletal intermediate filaments (IF) in different representatives of vertebrates. Enzyme activity was studied by the modified method of Padykula and Herman. A streptavididin-biotin immunohistochemical method was applied to reveal desmin (D) and vimentin (V) IF. Endothelial cells of all vessels were V-positive and D-negative and exhibit high ATPase activity. Vascular smooth muscle cells (SMC) in lower vertebrates (pisces and amphibia) were also V-positive and D-negative, but showed low ATPase activity. SMC were D-positive and V-negative and possessed high enzyme activity in aves and mammals, similar to that of the endothelium. In cow vascular wall D-reactivity and high ATPase activity were mostly expressed in bundles of mosaically arranged thick SMC fibres of the outer aortic media as well as in the longitudinal fibres in the inferior vena cava. In higher vertebrates SMC of vasa vasorum were both V- and D-positive and showed high enzyme activity. The results demonstrate that D-immunoreactivity is mostly expressed in SMC of layers of high functional activity, which correlates with the intense ATPase reaction in these cells.

Adenosine Triphosphatases↗
PubMed1991

Distribution of anionic sites in gut tissue: an electron-microscopical study.

A new one-step incubation method using cationic gold colloid was applied to reveal anionic moieties in rat colonic mucosa. Gold particles were detected in all cellular nuclei, basement membranes, mast cell granules and collagen fibres, while the luminal surfaces of all vascular endothelial cells were devoid of gold label. Application of the method for detection of anionic domains under various conditions is discussed.

Animals↗
PubMed1990

Superovulatory response of river bufalo (Bubalus bubalis ).

The ovarian response of 25 buffalo-cows was visually assessed, and their oviducts and uteri separately flushed 3 to 6 d post superovulatory estrus at slaughter. Ten buffalo-cows slaughtered on Days 5 and 6 were examined per rectum for corpora lutea (CL) and follicles > 8 mm prior to slaughter, and the estimate was compared later with the actual ovarian response. Five out of the ten buffalo-cows were nonsurgically flushed in vivo on Day 5 of the estrous cycle, a day before slaughtering, and as a result, six ova/embryos were recovered. After the flushing of the reproductive tract at slaughter, one more ovum was recovered from the uterus of each of the three buffalo-cows. As a result of treatment of three groups of five buffalo with 3000 IU pregnant mare serum gonadotrophin (PMSG) on Days 6, 10 or 14 of the estrous cycle, 3.8, 6.2 and 3.4 CL on the average were recovered, respectively (Experiment I). A mean number of 8.8 and 9.0 CL, respectively, was obtained in two groups of five buffalo each, after treatment with 40 mg of follicle stimulating hormone (FSH) on Day 10 of the stage of the estrous cycle (Experiment II) and 3000 IU PMSG regardless of the stage of cycle (Experiment III). The percentage of ova/embryos recovered in the three experiments was 32.8, 20.4 and 22.2, respectively.

Journal Article↗
PubMed1988

Successful nonsurgical embryo transfer in buffalo (Bubalus bubalis ) in Bulgaria.

Forty-one Day 5.0 to Day 5.5 embryos and one unfertilized ovum were recovered nonsurgically from 24 superovulated, parous buffalo (Bubalus bubalis ) and transferred nonsurgically to 28 synchronized recipients by a team of Bulgarian and American scientists. Five pregnancies were established and four live buffalo calves were born at the end of normal gestation periods.

Journal Article↗
PubMed1987

Studies on preimplantation development of buffalo embryos.

A total of 71 lactating and nonlactating buffalo-cows of the Murrah breed and F(1)-F(3) crossbreds of Murrah x Bulgarian buffalo were used for a year as donors of embryos after a preliminary treatment for superovulation induction with pregnant mare serum gonadotrophin (PMSG) or follicle stimulating hormone (FSH) in combination with prostaglandin F-2 alpha analog (PGF-2 alpha) according to general application procedures in cows. From 36 to 72 h following prostaglandin injection, the buffalo-cows were checked with the help of a teaser bull for detection of estrus. The animals in estrus were inseminated twice either naturally or artificially with frozen semen. Nonsurgical flushing of the uterine horns was done in 45 of the buffalo-cows between 108 and 162 h after the onset of estrus. After slaughter the uterine horns and oviducts of the other 26 animals were flushed separately between 74 and 108 h after the beginning of estrus. Seven late morulae and eight hatched blastocysts were recovered between 114 and 116 h from the onset of estrus as a result of nonsurgical flushing. All of the 40 embryos recovered after 117 h were in the hatched blastocyst stage. As a result of flushing the oviducts and the uterine horns of slaughtered donors between 74 and 100 h, eggs were obtained only from the oviducts, while flushing conducted between 102 and 108 yielded eggs from both the oviducts and the uterine horns.

Journal Article↗
PubMed1987

[Superovulation induction in buffalo cows (Bubalus bubalis) with follicle-stimulating hormone (FSH)].

A total of 19 buffalo cows were used to induce superovulation following a pattern that included the use of FSH at the rate of 40 mg in the course of four days, applied twice a day and of Oestrophan at 48 hours after the beginning of treatment. Fifteen animals manifested estrus and were twice inseminated. The superovulation response of the ovaries was 4.3 +/- 0.8 yellow bodies and 0.5 +/- 0.24 follicles greater than 8 mm. A nonsurgical method was employed to obtain 24 embryos of high quality and an unfertilized ovum from 8 buffalo cows.

Animals↗
PubMed1987

[Transplantation of embryos in sheep breeding].

Intra- and inter-breed transplantations were carried out with Bulgarian fresh embryos and with frozen embryos imported from Poland. A complex biotechnology was worked out, including methods of estrus synchronization, of inducing superovulation, and of producing, morphologic evaluation, storing, and transplantation of sheep embryos. Discussed are the possibilities of using embryo transplantation in sheep breeding for the fuller use of the reproductive potential of elite ewes as donors of embryos, for the introduction of new genotypes by means of importing frozen embryos as well as a modern model for fundamental investigations in the reproductive and cell biology.

Animals↗
PubMed1987

[The exchange of animals in the form of embryos].

The results are given of transplantation work with cattle embryos from Czechoslovakia. The embryos were taken in the stage of morula or blastocyst, frozen and stored for one to ten months. Following thawing they were transplanted via surgical methods to local, estrus-synchronized recipient heifers at the Ruzhevo Konare village, Plovdiv district. A calf was born to each of six of the recipients, while two heifers that were inseminated seven days prior to transplantation yielded twins. It was considered to be the result of both the embryo-transplantation and the fertilization of own ova. Discussed are the opportunities and advantages of long-term storage and shipping of animals in the form of frozen embryos.

Animals↗
PubMed1986

[Superovulation and the production of embryos in the water buffalo (Bubalus bubalis) in Bulgaria].

A total of thirty water buffalo cows aged 3 to 8 years were treated for superovulation over the July-October period. Nine of the animals were injected with FSH at the rate of 40 mg at 12-hour intervals in the course of 4 consecutive days, and the remaining 21 animals were injected with 3,000 IU gestyl in the middle of the luteal phase. Forty-eight hours after stimulation started both groups were treated with 500 micrograms cloprostenol. Five out of the 9 buffalo cows (55.5 per cent) of group I and 15 out of 12 buffalo cows (71.4 per cent) of group II manifested estrus at an average interval of 44.4 +/- 3.6 and 40.5 +/- 3.29 hours, respectively, following the application of cloprostenol. The superovulatory treatment of the animals of the two groups led to average values of 5.6 +/- 1.89 and 4.0 +/- 0.98 corpora lutea and 1.0 +/- 0.63 and 2.7 +/- 1.41 follicules larger than 8 mm; 2.6 +/- 1.60 and 2.1 +/- 0.94 embryos of high quality were obtained through the use of a nonsurgical method of flushing.

Animals↗
PubMed1986

[Treatment of Hodgkin's disease].

The data pertinent to 101 patients with Hodgkin's disease who had been subjected to splenectomy and combined radiation therapy and chemotherapy are analysed. The efficacy of the treatment was relatively dependent on the initial localization and the degree of the generalization and aggressiveness of the disease. Variations in the prognosis at individual stages of the disease may be ascribed to biological differences in the degree of malignancy that may be low moderate or high. The tendency toward limited progress of the disease and successful treatment during clinical stages I and II may be due to slightly impaired local antitumor immunity in the zones of initial malignant induction. Acceleration of the disease gene ralization stemmed from totally deranged antitumor immunity. It should be assumed, in accordance with the recirculation of malignant lymphocytes, that clinical stages I and II are not isolated stages of the disease, since the diaphragm has no barrier ability and there are difficulties in differentiating between stages II and III. The modern therapeutic remedies have reached the peak of their potentialities. This prompt the necessity of the search for new, still unknown biological methods, permitting the attainment of a more complete demalignancy.

Adult↗