Arnold M. Belker

Bio: Arnold M. Belker is an academic researcher from University of Louisville. The author has contributed to research in topics: Vasovasostomy & Vasectomy. The author has an hindex of 17, co-authored 47 publications receiving 2258 citations. Previous affiliations of Arnold M. Belker include American Urological Association.

Oral sildenafil in the treatment of erectile dysfunction. Sildenafil Study Group.

Abstract: BACKGROUND Sildenafil is a potent inhibitor of cyclic guanosine monophosphate hydrolysis [corrected] in the corpus cavernosum and therefore increases the penile response to sexual stimulation. We evaluated the efficacy and safety of sildenafil, administered as needed in two sequential double-blind studies of men with erectile dysfunction of organic, psychogenic, and mixed causes. METHODS In a 24-week dose-response study, 532 men were treated with oral sildenafil (25, 50, or 100 mg) or placebo. In a 12-week, flexible dose-escalation study, 329 different men were treated with sildenafil or placebo, with dose escalation to 100 mg based on efficacy and tolerance. After this dose-escalation study, 225 of the 329 men entered a 32-week, open-label extension study. We assessed efficacy according to the International Index of Erectile Function, a patient log, and a global-efficacy question. RESULTS In the dose-response study, increasing doses of sildenafil were associated with improved erectile function (P values for increases in scores for questions about achieving and maintaining erections were <0.001). For the men receiving 100 mg of sildenafil, the mean score for the question about achieving erections was 100 percent higher after treatment than at base line (4.0 vs. 2.0 of a possible score of 5). In the last four weeks of treatment in the dose-escalation study, 69 percent of all attempts at sexual intercourse were successful for the men receiving sildenafil, as compared with 22 percent for those receiving placebo (P<0.001). The mean numbers of successful attempts per month were 5.9 for the men receiving sildenafil and 1.5 for those receiving placebo (P<0.001). Headache, flushing, and dyspepsia were the most common adverse effects in the dose-escalation study, occurring in 6 percent to 18 percent of the men. Ninety-two percent of the men completed the 32-week extension study. CONCLUSIONS Oral sildenafil is an effective, well-tolerated treatment for men with erectile dysfunction.

A unique view on male infertility around the globe

Abstract: Infertility affects an estimated 15% of couples globally, amounting to 485 million couples Males are found to be solely responsible for 20-30% of infertility cases and contribute to 50% of cases overall However, this number does not accurately represent all regions of the world Indeed, on a global level, there is a lack of accurate statistics on rates of male infertility Our report examines major regions of the world and reports rates of male infertility based on data on female infertility Our search consisted of systematic reviews, meta-analyses, and population-based studies by searching the terms “epidemiology, male infertility, and prevalence” We identified 16 articles for detailed study We typically used the assumption that 50% of all cases of infertility are due to female factors alone, 20-30% are due to male factors alone, and the remaining 20-30% are due to a combination of male and female factors Therefore, in regions of the world where male factor or rates of male infertility were not reported, we used this assumption to calculate general rates of male factor infertility Our calculated data showed that the distribution of infertility due to male factor ranged from 20% to 70% and that the percentage of infertile men ranged from 2·5% to 12% Infertility rates were highest in Africa and Central/Eastern Europe Additionally, according to a variety of sources, rates of male infertility in North America, Australia, and Central and Eastern Europe varied from 4 5-6%, 9%, and 8-12%, respectively This study demonstrates a novel and unique way to calculate the distribution of male infertility around the world According to our results, at least 30 million men worldwide are infertile with the highest rates in Africa and Eastern Europe Results indicate further research is needed regarding etiology and treatment, reduce stigma & cultural barriers, and establish a more precise calculation

Advances in male contraception.

Abstract: Despite significant advances in contraceptive options for women over the last 50 yr, world population continues to grow rapidly. Scientists and activists alike point to the devastating environmental impacts that population pressures have caused, including global warming from the developed world and hunger and disease in less developed areas. Moreover, almost half of all pregnancies are still unwanted or unplanned. Clearly, there is a need for expanded, reversible, contraceptive options. Multicultural surveys demonstrate the willingness of men to participate in contraception and their female partners to trust them to do so. Notwithstanding their paucity of options, male methods including vasectomy and condoms account for almost one third of contraceptive use in the United States and other countries. Recent international clinical research efforts have demonstrated high efficacy rates (90-95%) for hormonally based male contraceptives. Current barriers to expanded use include limited delivery methods and perceived regulatory obstacles, which stymie introduction to the marketplace. However, advances in oral and injectable androgen delivery are cause for optimism that these hurdles may be overcome. Nonhormonal methods, such as compounds that target sperm motility, are attractive in their theoretical promise of specificity for the reproductive tract. Gene and protein array technologies continue to identify potential targets for this approach. Such nonhormonal agents will likely reach clinical trials in the near future. Great strides have been made in understanding male reproductive physiology; the combined efforts of scientists, clinicians, industry and governmental funding agencies could make an effective, reversible, male contraceptive an option for family planning over the next decade.