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Biomedical subjects

S Petrov

Publications and source records attributed to S Petrov.

At least 19 recordsLinked to original sources
PubMed2003

Endolymphatic infusion: human surgical investigation and application.

The ability to influence changes within the lymphatic system, and to exert a therapeutic influence on the composition and quality of the lymph, may have a substantial impact on the therapeutic outcome in disease interventions. This report concerns our experience with endolymphatic infusion (ELI) of drugs, an approach that we have utilized in a surgical context to destroy bacteria within lymphatic vessels and lymph nodes. Experimentally, we have demonstrated that a variety of antibiotics will temporarily decrease the contractile activity of the lymphatic vessels and reduce the volume of lymph flow. Based on our initial observations, we have applied endolymphatic infusion to clinical care. ELI was evaluated in the treatment of 330 patients, utilizing protocols to alter the characteristics of lymph flow.

Anti-Bacterial Agents↗
PubMed2003

Effect of angiotensin II type 1 (AT1) receptor antagonist on the endothelial dysfunction in spontaneously hypertensive rats in correlation with the nitric oxide system.

BACKGROUND: Hypertension is associated with impaired endothelial function, which can be explained by a decrease in nitric oxide (NO) generation or by an enhanced inactivation of NO after its release from endothelial cells. OBJECTIVES: The aim of this study was to investigate the effect of long-term treatment with losartan, an angiotensin II (AT1) receptor antagonist, on endothelial dysfunction in an animal model of hypertension in relation to the nitric oxide system. METHODS: Losartan was administered to 48 sixteen-week-old spontaneously hypertensive rats, in a dose of 10 mg/kg bw/daily in drinking water, for 12 weeks. Systolic blood pressure (SBP) was measured at the beginning, after 4, 8 and 12 weeks of treatment, by the tail-cuff plethysmographic method. At each mentioned time point, a group of 12 animals was sacrificed and blood was withdrawn from the abdominal aorta. Plasma samples were used for determination of total nitrate/nitirite levels, cyclic guanosine monophosphate (cGMP) and endothelin (ET) 1 levels. Statistical evaluation of the results was performed by the use of a computer statistical programme Statistica for Windows 5.0. RESULTS: Losartan produced a significant decrease of SBP at all time points. On the other hand, long-term treatment with this AT1 receptor antagonist produced a significant increase of nitrate/nitrite and cGMP plasma levels. When we compared the values of SBP with plasma nitrate/nitrite as well as with cGMP values, a statistically significant correlation was established. A statistically significant decrease in plasma endothelin 1 values was found during the whole study period. Also, a positive correlation between SBP and plasma endothelin 1 concentrations was observed. CONCLUSIONS: Long-term losartan (AT1 receptor antagonist) treatment, apart from its blood pressure lowering effect in hypertension, has beneficial effects on the endothelial dysfunction which is at least partially due to the activation of the nitric oxide system. (Tab. 1, Fig. 2, Ref. 33.)

Angiotensin II Type 1 Receptor Blockers↗
PubMed2000

Naked DNA and adenoviral immunizations for immunotherapy of prostate cancer: a phase I/II clinical trial.

INTRODUCTION AND OBJECTIVES: Animal studies have indicated that the use of syngeneic dendritic cells that have been transfected ex vivo with DNA for tumor-specific antigen results in tumor regression and decreased number of metastases. Additional studies have also suggested the possibility to modulate the dendritic cells in vivo either by 'naked' DNA immunization or by injecting replication-deficient viral vectors that carry the tumor-specific DNA. Using the prostate- specific membrane antigen (PSMA) as a target molecule, we have initiated a clinical trial for immunotherapy of prostate cancer. The primary objective of the study was to determine the safety of the PSMA vaccine after repeated intradermal injections. METHODS: We have included the extracellular human PSMA DNA as well as the human CD86 DNA into separate expression vectors (PSMA and CD86 plasmids), and into a combined PSMA/CD86 plasmid. In addition, the expression cassette from the PSMA plasmid was inserted into a replication deficient adenoviral expression vector. Twenty-six patients with prostate cancer were entered into a phase I/II toxicity-dose escalation study, which was initiated in spring 1998. Immunizations were performed intradermally at weekly intervals. Doses of DNA between 100 and 800 microg and of recombinant virus at 5x10(8) PFUs per application were used. RESULTS AND CONCLUSION: No immediate or long-term side effects following immunizations have been recorded. All patients who received initial inoculation with the viral vector followed by PSMA plasmid boosts showed signs of immunization as evidenced by the development of a delayed-type hypersensitivity reaction after the PSMA plasmid injection. In contrast, of the patients who received a PSMA plasmid and CD86 plasmid, only 50% showed signs of successful immunization. Of the patients who received PSMA plasmid and soluble GM-CSF, 67% were immunized. However, all patients who received the PSMA/CD86 plasmid and sGM-CSF became immunized. The patients who did not immunize during the first round were later successfully immunized after a boost with the viral vector. The heterogeneity of the medical status and the presence in many patients of concomitant hormone therapy does not permit unequivocal interpretation of the data with respect to the effectiveness of the therapy. However, several responders, as evidenced by a change in the local disease, distant metastases, and PSA levels, can be identified. A phase II clinical study to evaluate the effectiveness of the therapy is currently underway.

Adenoviridae↗
PubMed1999

Detection and typing of human papillomavirus in cervical carcinomas in Russian women: a prognostic study.

BACKGROUND: The correlation between human papillomavirus (HPV) infection and tumor prognosis in 159 Russian women with cervical carcinoma was investigated. The presence of various HPV types was correlated with the histologic parameters of the carcinomas and with their immunoreactivity with antibodies to p53, Ki-67-Ag, and bcl-2. METHODS: Formalin fixed, paraffin embedded tissue specimens representing 159 cases of International Federation of Gynecology and Obstetrics Stage I and II were used. HPV DNA was detected by polymerase chain reaction (PCR) using a general primer set that targets the L1 region and synthesizes a product of only 65 base pairs. The HPV types were determined by direct sequencing and compared with known HPV types. RESULTS: All 159 carcinomas were positive for HPV. HPV 16 (64.8%) was most frequently found, followed by HPV 18 (10.7%) and HPV 45 (8.2%). In 6 patients (3.8%), HPV types could not been further classified, and these cases were therefore categorized as HPV X. Although a trend was noted toward poorer prognosis for women with carcinomas harboring HPV types 16, 18, and 45 than for patients with carcinomas harboring HPV types 31, 33, 35, 52, 56, 58, and 68, the differences were not statistically significant. The prevalence of adenocarcinoma and adenosquamous carcinoma was higher among HPV 18 positive patients than among patients with the other known HPV types (P=0.0002). CONCLUSIONS: The rate of HPV positivity in these 159 cervical carcinomas was 100%. These findings challenge the assumption that HPV negative cervical carcinomas exist. This high rate might be attributed to the use of a new broad-spectrum HPV PCR test. HPV typing in cervical carcinoma was not significantly related to clinical outcome. HPV 18 was significantly more frequently found in adenocarcinoma and adenosquamous carcinoma. The possibility of classifying HPV 45 as an oncogenic high risk type should be considered.

Adult↗
PubMed1999

Characteristics and trends in macrolide resistance among Helicobacter pylori strains isolated in Bulgaria over four years.

Macrolide resistance trends were examined among Helicobacter pylori strains from 154 patients between 1994 and 1998. Applicabilities of screening agar method (SAM) and modified disk diffusion method (MDDM) were evaluated. Overall primary resistance rates to erythromycin and clarithromycin were 14.8% and 8.7%, respectively. No association was found with age, sex, and diseases. Clarithromycin-resistance rate reached 12.5% in the last 2 years. Secondary resistance to erythromycin occurred more often (in 62.5%) than to clarithromycin (in 42.9%). Therapy with spiramycin or erythromycin in four cases induced no clarithromycin resistance. These data show a considerable prevalence of H. pylori resistance to macrolides, which exhibited a tendency to increase and was often associated with metronidazole resistance. By comparing the MDDM with SAM, an overall agreement was obtained in 81 (94.2%) of 86 results. MDDM and SAM are reliable techniques for testing H. pylori susceptibility to macrolides.

Adolescent↗
PubMed1996

Instability of chromosome 6 microsatellite repeats in human cervical tumors carrying papillomavirus sequences.

Loss of heterozygosity (LOH) in chromosome 6 in human squamous cervical carcinomas was analyzed in the long and short arms of the chromosome using 3 pairs of primers each. In all cases, normal adjacent tissue was used as control. Among 51 cases analyzed, we identified LOH or microsatellite instability in 23% using primer D6S291 (located at position 6p21.3) and in 11% using primers D6S308 (6q16.3-6q27) and D6S270 (6q22.3-6q23.2). On the contrary, no significant LOH or genomic instabilities were detected with primers D6S306 (6p22.3-6p21.2), D6S299 (6p22.3-6p21.3) and D6S287 (6q21-6q23.3). Our results thus suggest the existence of instable loci at 3 regions of chromosome 6. Whether these loci contain putative tumor-suppressor genes or genes involved in cell cycle control remains unknown.

Adenocarcinoma↗
PubMed1996

Comparison of three urease tests for detection of Helicobacter pylori in gastric biopsy specimens.

OBJECTIVE: To propose two modified urease tests for the detection of Helicobacter pylori in gastric biopsy specimens. PATIENTS AND METHODS: The presence of H. pylori infection was determined in 237 patients undergoing upper gastrointestinal endoscopy. Three media were used for the urease tests: Christensen's 2% urea broth and two urea agar media, modified by increasing the concentration of urea (to 4% and 10%) and phenol red and omitting the nutrients. RESULTS: The modified tests had good sensitivity (> 78%), specificity (96%) and accuracy (> or = 86%) at 2 h using small amounts (15%) of biopsy homogenates. They were statistically more sensitive and accurate than Christensen's broth. CONCLUSION: Both the modified 4% and 10% urea agar tests are simple, sensitive and specific and can be performed with small amounts of sample.

Bacteriological Techniques↗
PubMed1994

[Pancreatoduodenal resection for carcinoid of Vater's papilla].

Papilla Vateri carcinoid is among the very rarely occurring locations of the lesion. The small lumen of the papilla is the underlying cause of becoming clinically manifest with icterus rather early. Accessibility of the process for endoscopic biopsy facilitates the diagnosis. Even histologically it is very difficult to differentiate benign from malignantly altered carcinoids. Only the existence of metastases confirm with certainty their malignant nature. An observation on papilla Vateri carcinoid in a 60-year-old woman, proved preoperatively through cytological study, is reported. Intraoperative--no metastases are discovered. Sparing pancreatoduodenal resection is performed with a good functional outcome, recorded at the checkup examination after two years.

Ampulla of Vater↗
PubMed1987

[Echinococcosis of the heart and parasitic embolism of a cerebral artery].

The primary echinococcus of the heart is known to be a great rarity. A review of the Bulgarian scientific periodicals of the last thirty years reveals only twelve reports of such localization. A rare case of primary echinococcus cyst of the myocardium of the left ventricle with a rupture and a brain cyst embolism is reported in the present paper.

Adult↗
PubMed1984

[Attempt to analyze the extrahospital time in managing an acute myocardial infarct patient].

The time of prehospital attendance of patients with acute myocardial infarction is analyzed for the period 1970-1983 by an emergency team according to a scheme of the stages and time for transport, communication and therapy respectively. The duration of the separate stages is determined and a conclusion is drawn that the time for communication and transport is most protracted, and the time for the therapy of a non complicated infarction--is one fourth of the total attendance time. Potentialities are looked for in order to shorten the stages by the regulation of the team, including a stretcher-bearer and a nurse, the necessity of qualification of all teams. The statistical processing of the material is presented as well as a scheme with the outcome of 230 myocardial infarctions--survival, total mortality rate and lethality, 314 patients were followed up as regards hospitalization and a correlation is presented of the members of the team and attendance time with respresentative and chronometric methods.

Aged↗