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Biomedical subjects

A R Ronald

Publications and source records attributed to A R Ronald.

At least 55 records · Page 3Linked to original sources
PubMed1990

Geographical patterns of male circumcision practices in Africa: association with HIV seroprevalence.

To ascertain whether male circumcision might explain some of the geographical variation in human immunodeficiency virus (HIV) seroprevalence in Africa, we investigated the association between the practice of male circumcision at a societal level and HIV seroprevalence. Male circumcision practices for over 700 African societies were identified, and HIV seroprevalence in general adult populations from 140 distinct locations in 41 countries was obtained. In locations where male circumcision is practised, HIV seroprevalence was considerably lower than in areas where it is not practised. This study supports the hypothesis that lack of circumcision in males is a risk factor for HIV transmission.

Adolescent↗
PubMed1990

The value of single-dose therapy to diagnose the site of urinary infection.

Several single dose regimens have been shown to cure 90 percent of women with acute cystitis in whom infection is confined to the bladder. About 25 percent of women with acute cystitis and approximately one-half with asymptomatic infection have organisms originating from one or both upper urinary tracts. Effective single dose regimens such as trimethoprim-sulfamethoxazole, amoxicillin, and trimethoprim alone, cure between 40 and 60 percent of upper tract infections in women with renal involvement, who present with acute cystitis or with asymptomatic bacteriuria. Five studies have shown that single dose failure in women with acute cystitis or asymptomatic bacteriuria is a specific predictor of upper tract infection. It is also sensitive (60-80 percent) in predicting upper tract pathology. The evidence to date favours the hypothesis that failure of single dose cure following treatment with an effective single dose regimen in adult women who have asymptomatic bacteriuria or acute cystitis, identifies a subset of women who require further investigation of the urinary tract.

Anti-Infective Agents, Urinary↗
PubMed1990

Human immunodeficiency virus, genital ulcers and the male foreskin: synergism in HIV-1 transmission.

Epidemiologic studies in Nairobi and elsewhere in Africa, have shown that men infected with HIV-1 more commonly have a history of genital ulcer disease compared to uninfected men. In one study, HIV infected men were three times as likely to have a recent history of genital ulcers. In a prospective study of seronegative men, those presenting with chancroid had a five-fold risk of seroconversion during follow-up compared to men presenting with urethritis. Uncircumcised men had an increased risk of seroconversion which was independent of their risk of genital ulcer disease. Over 95% of attributable risk in men with STD was either genital ulceration or the presence of a foreskin. Genital ulcers are a major risk factor for HIV infection among prostitutes. The increased risk is about 10-fold among prostitutes with ulcers compared to a cohort who did not. We hypothesize from these studies that genital ulcers are the major portals of entry for HIV infection and also increased shedding of virus infected cells into the vaginal secretions. HIV seropositive prostitutes are more susceptible to chancroid with a two-fold increase in the prevalence of genital ulcers as compared to HIV negative women. The use of condoms by their clients prevents both genital ulcer disease and HIV acquisition among prostitutes. Chancroid is more difficult to treat in HIV infected men with one-third of patients failing single dose treatment regimens as compared to less than five percent of men without HIV infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1989

Female to male transmission of human immunodeficiency virus type 1: risk factors for seroconversion in men.

To determine the frequency and risk factors for female to male sexual transmission of human immunodeficiency virus type 1 (HIV-1), a prospective study was carried out in 422 men who had acquired a sexually transmitted disease (STD) from a group of prostitutes with a prevalence of HIV-1 infection of 85%. The initial seroprevalence of HIV among the men was 12%. 24 of 293 (8.2%) initially seronegative men seroconverted to HIV-1. Newly acquired infection was independently associated with frequent prostitute contact (risk ratio 3.2, 95% confidence interval 1.2-8.1), with the acquisition of genital ulcer disease (risk ratio 4.7, 95% confidence interval 1.3-17.0), and with being uncircumcised (risk ratio 8.2, 95% confidence interval 3.0-23.0). 96% of documented seroconversions occurred in men with one or both of the latter two risk factors. In a subgroup of 73 seronegative men who reported a single prostitute sexual contact, the frequency of HIV-1 infection was 8.2% during 12 weeks of observation. No man without a genital ulcer seroconverted. A cumulative 43% of uncircumcised men who acquired an ulcer seroconverted to HIV-1 after a single sexual exposure. These data indicate an extremely high rate of female to male transmission of HIV-1 in the presence of STD and confirm a causal relation between lack of male circumcision, genital ulcer disease, and susceptibility to HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Production of monoclonal antibodies specific for Haemophilus ducreyi: a screening method to discriminate specific and cross-reacting antibodies.

Haemophilus ducreyi is the etiological agent of chancroid. The organism shares extensive immunological cross-reactivity with other Haemophilus species. This presents substantial difficulties for the production of specific monoclonal antibodies (MAbs). A competition ELISA was devised for hybridoma screening which allowed the detection of H. ducreyi-specific antibody-producing hybridoma cultures during the initial screening process. With this screening method, seven MAbs specific for H. ducreyi were obtained in a single cell fusion exercise. The specificities of the 7 MAbs were demonstrated by direct ELISA and dot immunobinding assays against several strains each of H. influenzae, H. parainfluenzae and Neisseria gonorrhoeae. Five of the MAbs reacted against all ten strains of H. ducreyi. These MAbs may permit the development of rapid and efficient immunodiagnostics for chancroid. The principle of the competition ELISA for hybridoma screening should be widely applicable to the development of specific MAbs to other organisms in which immunological cross-reactivity is an impediment to hybridoma screening by conventional methods.

Animals↗
PubMed1989

Once-daily therapy with ceftriaxone compared with daily multiple-dose therapy with cefotaxime for serious bacterial infections: a randomized, double-blind study.

A randomized, double-blind study was done to compare the efficacy and toxicity of daily single-dose therapy with intravenous ceftriaxone (2 g every 24 h) with daily multiple-dose therapy with cefotaxime (2 g every 6 h) for treatment of serious bacterial infections in nonneutropenic patients. Of the 325 patients who were evaluable for toxicity, 241 (74.2%) were evaluable for efficacy. Infection sites included lung (106), urinary tract (42), skin and soft tissue (43), bone and joint (23), bacteremia (21), and hepatobiliary (5). Definite infections were present in 173 cases (71.8%) and possible infections in 68 (28.2%). Analysis of clinical and bacteriologic responses and adverse drug reactions showed no significant differences between the regimens. Values for 95% confidence limits on the differences between regimens for positive clinical and bacteriological outcomes in definite infections were -0.8% to 3.0% and -1.9% to 9.1%, respectively. Thus, daily single-dose therapy with ceftriaxone was comparable to daily multiple-dose therapy with cefotaxime in treating these bacterial infections.

Adult↗
PubMed1989

Evaluation of fleroxacin (RO 23-6240) as single-oral-dose therapy of culture-proven chancroid in Nairobi, Kenya.

Chancroid is gaining importance as a sexually transmitted disease because of its association with transmission of human immunodeficiency virus type 1 (HIV-1). Effective, simply administered therapy for chancroid is necessary. Fleroxacin is effective against Haemophilus ducreyi in vitro. We performed an initial randomized clinical trial to assess the efficacy of fleroxacin for treatment of chancroid in Nairobi, Kenya. Fifty-three men with culture-positive chancroid were randomly assigned to receive either 200 mg (group 1) or 400 mg (group 2) of fleroxacin as a single oral dose. Groups 1 and 2 were similar with regard to severity of disease, bubo formation, and HIV-1 status. A satisfactory clinical response to therapy was noted in 23 of 26 patients (88%) in group 1 and 18 of 23 patients (78%) in group 2. Bacteriological failure occurred in 1 of 26 evaluable patients (4%) in group 1 and 4 of 23 evaluable patients (17%) in group 2. Two of 37 HIV-1-seronegative men (5%) and 3 of 11 HIV-1-infected men (27%) were bacteriological failures. Fleroxacin, 200 or 400 mg as a single oral dose, is efficacious therapy for microbiologically proven chancroid in patients who do not have concurrent HIV-1 infection. Among HIV-1-infected men, a single dose of 200 or 400 mg of fleroxacin is inadequate therapy for chancroid.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Prospective, randomized, placebo-controlled trial of norfloxacin for the prophylaxis of recurrent urinary tract infection in women.

Thirty women were randomized in a double-blind, placebo-controlled study to receive either norfloxacin, 200 mg orally daily at bedtime, or placebo for the prevention of recurrent bladder infection. Subjects were followed monthly to monitor compliance and symptoms, for urine culture and periurethral and anal canal swabs to monitor colonization, and for blood specimens for hematologic and biochemical studies to monitor safety. During 1 year of follow-up, 10 of 15 placebo subjects and none of 15 norfloxacin subjects developed infection (P less than 0.001). Adverse effects occurred with equal frequencies in the two groups. For norfloxacin subjects, only 2 (1.6%) of 129 periurethral and 4 (3.1%) of 129 anal canal swabs showed colonization with aerobic gram-negative organisms, while 16 (22%) of 73 periurethral and 47 (64%) of 73 anal canal swabs from placebo subjects showed colonization. Daily therapy with norfloxacin at bedtime is effective in preventing recurrent cystitis. During 1 year of norfloxacin therapy, colonization was infrequent and superinfection with norfloxacin-resistant organisms did not occur.

Adult↗
PubMed1989

Chancroid and granuloma inguinale.

Haemophilus ducreyi is a fastidious pathogen that can be routinely cultured with the appropriate media and incubation environment. Prostituted women appear to be the usual reservoir. In Africa, chancroid is emerging as the major risk factor for acquisition of HIV-1 following heterosexual intercourse. Despite the emergence of resistance to a number of antimicrobial agents, H. ducreyi remains susceptible to ceftriaxone, erythromycin, and ciprofloxacin. Control and eradication of outbreaks of chancroid have been successful on several occasions in Western societies; strategies to control epidemic genital ulcer disease are required in developing countries. Granuloma inguinale is caused by a small, gram-negative rod, which has never been well-characterized. The presence of Donovan bodies is a specific and sensitive diagnostic characteristic. Very little is known about the epidemiology of the disease. Specific treatment programs using trimethoprim-sulfamethoxazole or erythromycin seem to be quite effective. Control strategies have not been adequately investigated.

Campylobacter↗
PubMed1989

Antimicrobial therapy: past, present, and future.

Antimicrobial chemotherapy is a growth industry in the rapidly changing world of health care. The identification of new pathogens, new treatment modalities, and new issues related to our patterns of antimicrobial use ensure that the practise of Infectious Diseases in 1994 will be markedly different than it has been in 1988. Ongoing adaptation and radical change will both be required of each one of us as we modify our treatment guidelines to ensure that our patients receive optimal antimicrobial therapy for maintaining or regaining their health.

4-Quinolones↗
PubMed1988

Prevention of transmission of human immunodeficiency virus in Africa: effectiveness of condom promotion and health education among prostitutes.

Condom use was assessed after a programme of education about the acquired immunodeficiency syndrome and a condom distribution programme in a well-characterised prostitute population in Nairobi. Women received their education at group meetings (barazas) and at individual counselling sessions during which they were given the results of serological tests for the human immunodeficiency virus (group 1) or at barazas only (group 2), or through very little of either (group 3). During the counselling sessions free condoms were distributed. Before either of the programmes started, 10%, 9%, and 7% of groups 1, 2, and 3 women, respectively, reported occasional use of condoms. By November 1986, 80%, 70%, and 58% of groups 1, 2, and 3 women, respectively, reported at least some condom use. The mean frequency of condom use was 38.7 (SD 31.8)%, 34.6 (34.5)%, and 25.6 (29.5)% of sexual encounters in groups 1, 2, and 3 women. 20 of 28 women who were non-condom-users seroconverted compared with 23 of 50 women who reported some use of condoms.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Human immunodeficiency virus infection among men with sexually transmitted diseases. Experience from a center in Africa.

Heterosexual transmission of the human immunodeficiency virus (HIV) appears to occur readily in Africa but less commonly in North America and Europe. We conducted a case-control study among men attending a clinic for sexually transmitted diseases in Nairobi to determine the prevalence of HIV infection and the risk factors involved. HIV antibody was detected in 11.2 percent of 340 men who enrolled in the study. Reports of nonvaginal heterosexual intercourse and homosexuality were notably rare. Recent injections and blood transfusions were not associated with HIV infection. Travel and frequent contact with prostitutes were associated with HIV seropositivity. Men who were uncircumcised were more likely to have HIV infection (odds ratio, 2.7; P = 0.003), as were those who reported a history of genital ulcers (odds ratio, 7.2; P less than 0.001). A current diagnosis of genital ulcers was also associated with HIV seropositivity (odds ratio, 2.0; P = 0.028). Multivariate analysis revealed an independent association of genital ulcers with HIV infection in both circumcised and uncircumcised men. Uncircumcised men were more frequently infected with HIV, regardless of a history of genital ulcers. Our study finds that genital ulcers and an intact foreskin are associated with HIV infection in men with a sexually transmitted disease. Genital ulcers may increase men's susceptibility to HIV, or they may increase the infectivity of women infected with HIV. The intact foreskin may operate to increase the susceptibility to HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Prophylaxis of gonococcal and chlamydial ophthalmia neonatorum. A comparison of silver nitrate and tetracycline.

We evaluated the use of silver nitrate drops and tetracycline ointment for the prophylaxis of ophthalmia neonatorum in a controlled trial involving 2732 newborns in Nairobi, Kenya. The overall rates of prevalence of intrapartum maternal gonococcal and chlamydial infection were 6.4 and 8.9 percent, respectively. After prophylaxis with silver nitrate, the incidence rates of gonococcal, chlamydial, and nongonococcal, nonchlamydial ophthalmia neonatorum were 0.4, 0.7, and 6.2 percent, respectively, whereas after prophylaxis with tetracycline, the rates were 0.1, 0.5, and 4.5 percent. The attack rates of gonococcal ophthalmia neonatorum in newborns exposed to Neisseria gonorrhoeae at birth were 7.0 percent in those receiving silver nitrate and 3.0 percent in those receiving tetracycline (95 percent confidence interval for the difference in rates, -3.4 to 11.4 percent). As compared with historical controls, the incidence of gonococcal ophthalmia neonatorum decreased 83 percent among infants treated with silver nitrate and 93 percent among those treated with tetracycline. Failure of prophylaxis was associated with postpartum maternal endometritis (P = 0.05). Among newborns exposed to maternal infection with Chlamydia trachomatis, chlamydial conjunctivitis developed in 10.1 percent given silver nitrate and in 7.2 percent given tetracycline (95 percent confidence interval for the difference in rates, -4.7 to 10.5 percent), yielding reductions in the incidence of chlamydial ophthalmia of 68 and 77 percent, respectively, as compared with the historical controls. We conclude that tetracycline is as effective as silver nitrate in preventing gonococcal ophthalmia neonatorum.

Chlamydia Infections↗