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Biomedical subjects

I Mladenova

Publications and source records attributed to I Mladenova.

12 recordsLinked to original sources
PubMed2006

Transmission of Helicobacter pylori: are there evidences for a fecal-oral route?

Helicobacter pylori (H. pylori) infection spreads from person-to-person, however the precise mode of transmission (oral-oral, fecal-oral or gastro-gastric) is hitherto not known. Gaining understanding into the spread of the bacterium might be useful in identifying high-risk populations, especially in areas that have high rates of gastric malignancies or peptic ulcer. In this review, the authors analyze the aspects concerning the plausibility for the fecal-oral route on the basis of the available data.

Animals↗
PubMed2006

[Gastric cancer and Helicobacter pylori: an interdisciplinary point of view].

Gastric carcinogenesis involves a slow but continuous, stepwise evolution from superficial gastritis to glandular atrophy, metaplasia, dysplasia, and finally, to adenocarcinoma. In 1994, the International Agency for Research on Cancer defined Helicobacter pylori (H. pylori) as a group I carcinogen. Evidence supporting a causal association has been demonstrated by epidemiological data as well as by experimental animal models. The process of carcinogenesis, which may well extend over decades, provides an excellent opportunity for prevention or early detection of the events preceding development of the neoplasm. This is especially true because, at present, H. pylori can be readily treated. Despite this, the prognosis for gastric cancer is poor and, in most industrialised countries, the survival is only 10% after 5 years from diagnosis. The sole exception is Japan where this malignancy is often identified at an early stage when cure by radical surgery is more probable.

Adenocarcinoma↗
PubMed2004

The epidemiology of hepatitis C virus infection. An update for clinicians.

Since the advent of sensitive diagnostic blood tests for the detection of antibody to hepatitis C virus (HCV) in donors, there has been a large decline in the incidence of transfusion-related hepatitis. Globally, the infection has an estimated prevalence of 3%, with a prevailing 1% in Europe while varying geographically within a North-South gradient, ranging from around 0.5% in Northern countries to 2% in Mediterranean area. The incidence is very difficult to estimate accurately as many patients with acute HCV infection are asymptomatic and, thus, do not present for diagnosis. Data from the US report a fall in the annual occurrence of new cases per year from 230,000 in the late 1980s to approximately 35,000 in the 1990s. Therefore, a reduction in incident cases might eventually lead to lower prevalence of HCV infection. Although the incidence of viral infection may be decreasing, the prevalence of liver disease caused by HCV is on the rise. This is due to the significant lag, often 20 years or longer, between the onset of infection and clinical manifestation of liver disease. HCV can be transmitted by a variety of routes. It is most efficiently passed on by large or repeated percutaneous exposures such as through transfusions, transplantation from an infected donor or intravenous drug use. Transmission may also occur from contacts with infected subjects in the household, through perinatal and parenteral exposures in the health care setting. The risk of sexual transmission of HCV is low. Despite this knowledge, nearly half of infected patients do not have a history suggesting a parenteral route of acquisition. Since a prophylactic vaccine is hitherto not available, prevention becomes extremely important: identification of infected persons and of risk factors associated with acquiring HCV allow to develop strategies for preventing the spread of infection as well as its complications, and for planning appropriate care and support services.

Hepatitis C↗
PubMed2003

Infectious agents and gastric tumours. An increasing role for Epstein-Barr virus.

Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV) are 2 common and widely disseminated agents throughout the world. H. pylori has been classified, by the International Agency for Research on Cancer conference, as a class I carcinogen, i.e. undoubted cause of gastric cancer. However, this infection does not explain all the epidemiological and histological variations of the malignancies affecting the stomach. EBV has been identified, in the last decade, in the tumour cells of patients with gastric carcinoma and recent findings suggest the possibility of distinct mechanisms in its pathogenesis. A prevalent role of the virus has been described in a subset of stomach cancers, namely lymphoepithelioma-like carcinomas. The present update attempts to focus on the epidemiological evidence and the biological plausibility for a causal role of H.pylori and EBV infection in the pathogenesis of gastric cancer.

Epstein-Barr Virus Infections↗
PubMed1999

Is there an association between Helicobacter pylori infection and coronary heart disease?

In addition to gastroduodenal diseases, Helicobacter pylori infection has been associated with extradigestive diseases, including coronary heart disease. Different studies have failed to demonstrate a clear association. The aim of this work was to carry out a meta-analysis of these studies' results, with a special emphasis on heterogeneity. A MEDLINE search of all studies published in English from 1994 to 1998 was conducted. Five criteria for eligibility of studies were defined. The quality of each study was assessed on a five-point scale adapted from studies by the Quebec Task Force. The final results are reported based on a fixed-effects model. Pooled odd ratios were calculated for subgroups of studies (defined on quality of adjustment, on confounding factors, and on the type of control population). Sixty-nine articles and abstracts fulfilling the defined criteria were analyzed. They were all case-control or cross-sectional studies. H. pylori diagnosis was carried out by serology, urea breath test or both; coronary heart disease was diagnosed mainly by coronary angiography. The total sample size was 6603. The quality score varied from 4 to 10. The pooled odds ratios of the 24 articles included in the model was 1.55 (95% confidence interval (CI): 1.38-1.74). It ranged from 1.07 to 2.34 when the quality of adjustment for confounding factors was considered and from 1.25 to 1.99 when the type of control group was considered. In any case there was significant heterogeneity (p < 0.001). The present study demonstrated a possible weak association but the high degree of heterogeneity in the studies impedes a clear demonstration.

Age Distribution↗
PubMed1986

[Regulation of the reproductive functions of cows by hormonal preparations].

Studied was the effect of some hormonal preparations--progesteron, GnRH, and HCG with progesteron--injected immediately prior to artificial insemination on the reproductional functions of cows raised under industrial conditions. It was found that the conception rate of cows at first insemination was highest upon treatment with GnRH--67.86 percent, i.e., by 14.29 percent higher than that of the control group. The same trend remained with the total conception rate. Lowest was the use of pellets per cow--1.33--with animals treated with GnRH prior to insemination. The application of GnRH (Berlin Chemie, GDR) was sufficiently effective at single i/m injection before artificial insemination. It could be employed to raise conception rate as well as to lower the use of pellets for impregnation of cows.

Animals↗
PubMed1985

[Microbiological research on processed cheese].

Microbiologic studies were carried out with a total of 136 batches of 8 assortments of softened cheese to establish the amount and composition of the microbial content of this product. It was found that the total count of mesophilic organisms of 72.8 per cent of the investigated batches reached up to 200 000/g. The content of hygiene-indicative organisms (coliforms and enterococci) was limited: 97 per cent of batches had a coli titer of 1 and over 1. The content of enterococci in 54.4 per cent of the investigated was below 100/g, and in 4.4 per cent it was over 100 000/g. No Salmonella bacteria and plasmacoagulase positive staphylococci in 25, resp., 10 g of the product were found. Contamination with sporeforming aerobic and anaerobic organisms in 72.1, resp., 91.9 per cent reached up to 1000, resp., 100 per gram of the product. The amount of proteolytic bacteria in 61.8 per cent of the batches was up to 1000/g, and in 8 per cent only--up to 100 000/g. The content of yeasts and moulds in 58.8, resp. 83.1 per cent of the batches was below 100/g.

Bacteria↗
PubMed1984

Removal of histone H1 exposes linker DNA in chromatin to DNAse I.

After removal of histone H1 about 40% of DNA in chromatin acquires the sensitivity of naked DNA to DNAse I. Digestion of H1-depleted chromatin with DNAse I leads to a qualitative change in the digestion pattern, generating DNA fragments of approx. 200 b.p. and multiples, similar to those obtained with micrococcal nuclease. Both effects are reversed upon reconstitution of purified H1 to H1-depleted chromatin.

Animals↗