Background: CagA (cytotoxin-associated gene A protein) is an oncoprotein produced by Helicobacter pylori, a bacterium implicated in gastric carcinogenesis. CagA has been identified in all H. pylori strains isolated from patients with gastric cancer. To date, comparative studies investigating the genetic diversity of the cagA gene at the international level remain limited, and its pathogenic mechanisms have not yet been fully elucidated. Aim: To characterize the global and regional diversity of the cagA gene in H. pylori, and to evaluate the relationship of its prevalence and genotypic variants with gastric cancer. Materials and Methods: This molecular epidemiological study analyzed 9,276 H. pylori genomes from human hosts across 93 countries that were publicly available in international databases as of November 2024, together with 300 newly generated whole-genome sequences of H. pylori isolates from the Mongolian population that had not previously been deposited in public databases. To determine the genetic diversity of this oncogene, comprehensive genome bioinformatics analyses were performed, including genomic, phylogenetic, genotypic, and in silico protein analyses. Result: After quality control, 7,150 H. pylori genomes were included in the final analysis. Overall, 80.9% (n=5,783) of H. pylori strains were found to harbor the cagA gene, with the highest prevalence observed in Asia and the lowest in Europe. Maximum-likelihood phylogenetic analysis revealed substantial genotypic diversity of cagA and marked geographic variation in its distribution. Specifically, five distinct CagA protein types were identified, two of which represented previously undescribed novel types. The distribution of CagA types was found to correlate more strongly with the incidence of gastric cancer than the mere presence of cagA-positive H. pylori. Conclusion The majority of H. pylori strains in human populations worldwide harbor the CagA oncoprotein, with an overall prevalence of approximately 81%. Differences among CagA types may contribute to regional variation in gastric cancer risk. The diversification and evolutionary changes of the cagA gene may reflect recent processes of genetic admixture, which in turn shape its geographic and ethnic distribution as well as its pathogenic potential.

Introduction: Erectile dysfunction (ED), also known as impotence, is defined as a consistent or recurrent inability to attain and/or maintain penile erection sufficient for sexual performance [1]. According to recent study results, ED occurs more than 50% over 60 year old males, emphasizing a need to diagnose and treat it at an earlier stage. ED may be assessed in several ways. The most widely used standardized questionnaire is the International Index of Erectile Function (IIEF) with 15 questions, which also exists in a short form with 5 questions [2]. On the other hand, ED is associated with a decreased level of androgens in aging males; the latter is often referred to as a Late Onset Hypogonadism (LOH) or Testosterone Deficiency Syndrome (TDS). In simple terms, LOH or TDS can be defined as a decreased serum testosterone level in aging males [3, 4]Objective: To detect the testosterone deficiency syndrome in aging males with erectile dysfunction. Materials and Methods. 309 males over 40 years of age who received medical care at the ADAM urological and andrological clinic from 2010 to 2011 were included in this study. An approval of the Ethical Committee of MOH was obtained at the commencement of the study. Each study participant signed a consent form at the beginning of the study. Each participant was assigned to either an ED group or a control group depending on results of the IIEF-5 questionnaire. The ED group was further divided into three groups (moderate, severe and very severe) based on a level of ED. The total testosterone (TT) levels were determined in blood serum, using a competitive ELISA analytical system UBI MAGIWELTM TestosteroneQuantitative test (GLS, USA), with C.V. (%) 6.8 and free testosterone (FT) calculated as described by Vermeulen. Test samples were collected between 8.00-11.00 am. The biochemical diagnosis of TDS was based on the Study Aging Male (ISSAM) guidelines of the International Society, particularly, if TT was _3.46 ng/ml or free testosterone FT was ≤0.072 ng/ml [5].Results: ED of moderate, severe and very severe levels were diagnosed in 199 (64.41%) out of 309 participants. There was an inverse association between an erectile function and age (r=-0.380, p <0.01). The average TT was 5.75±2.316 ng/ml and FT was 0.091±0.0084 ng/ml. Compared to the ED group, the control group had a higher TT level: 5.6440±1.177 ng/ml and 5.812±2.316 ng/ml respectively. In the control group the FT level was 0.061±0.0084 ng/ml whereas it was 0.041±0.0076 ng/ml in the ED group. Conclusion: Our study showed that most of aging males who came to the clinic had a moderate to very severe ED (64.55%). The level of TT (5.644±1.177 ng/ml) and FT (0.041±0.0036 ng/ml) was significantly lower in ED patients (p<0.05). The testosterone deficiency syndrome was detected in 24.27% of the ED group.