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Biomedical subjects

R C Ballard

Publications and source records attributed to R C Ballard.

87 records · Page 5Linked to original sources
PubMed1977

Urethritis in white men--a microbiological appraisal.

The incidence of infections with Neisseria gonorrhoeae, Chlamydia trachomatis and mycoplasmas has been assessed in White men with urethritis who were attending a Johannesburg clinic for sexually transmitted diseases. Infection with N. gonorrhoeae was demonstrated in 54% of 212 patients with urethritis. C. trachomatis was isolated from 37% of patients with non-gonococcal urethritis, and from 25% with proven gonococcal infection. Although T-mycoplasmas were isolated significantly more often from patients with urethritis (41%) than from controls (23%) (P less than 0,05) their role in the aetiology of urethritis is uncertain.

Adolescent↗
PubMed1977

A microbiological investigation of acute summer gastroenteritis in black South African infants.

A microbiological investigation of Black infants suffering from severe acute summer gastroenteritis revealed enteropathogenic agents in 30 out of 37 patients (81%). Enterotoxigenic bacteria were isolated from 15 patients (41%). A total of 16 enterotoxigenic strains were isolated, comprising 9 enterotoxigenic Escherichia coli strains secreting labile and stable toxin on their own and in combination, and labile-toxin secreting strains of Klebsiella pneumoniae (4), Enterobacter cloacae (2) and Proteus vulgaris (1). In the case of the latter three species, however, 6 out of the 7 strains were isolated from patients who were excreting other enteric pathogens, whereas only 2 out of 9 enterotoxigenic E. coli patients had concomitant infections with other pathogens. No invasive bacteria were isolated except for 2 shigella strains. Salmonella and shigella strains were found in four patients. No correlation was found between the enteropathogenicity of E. coli and its serotype. Rotavirus was observed by negative staining electron microscopy in only two patients (6%) but using a reverse complement fixation test rotavirus antigen was detected in the stool of 17 out of 35 patients (49%). The low EM detection rate may well be due to the patients being admitted for treatment late in the course of their illness when the degree of viral shedding has decreased below EM detectability. No significant difference in clinical presentation was noted between the various aetiological agents. Only one patient was being solely breast-fed compared to 16% of control non-diarrhoeic infants. Evidence of malnutrition was noted in over half of our patients.

Acute Disease↗
PubMed1974

Interactions of TRIC agents with macrophages: effects on lysosomal enzymes of the cell.

TWO CHANGES WERE OBSERVED IN THE ACID PHOSPHATASE OF MACROPHAGES THAT HAD INGESTED INFECTIVE TRIC ORGANISMS: the proportion of extralysosomal enzyme rose, while the total amount in the cells fell. Both effects were directly related to the number of organisms ingested and increased with time. When macrophages were inoculated with more than 50 organisms per cell, changes were obvious within a few hours; with 2-10 organisms per cell changes were detectable only after 18 hr. or more. Enzyme appeared in the culture medium as the amount in the cells decreased. Ingestion of organisms killed by heat or treated with antibody did not induce such changes. In infected BHK-21 cells, no changes in acid phosphatase were detected at any stage of the developmental cycle of the organism.

Acid Phosphatase↗
PubMedDate not supplied

Etiology of genital ulcerations in Swaziland.

The etiology of genital ulcer disease was determined among 155 consecutive new cases in Mbabane, Swaziland. In contrast to genital ulcerations in industrialized countries, chancroid was the most common diagnosis (44% of cases), as established on clinical grounds and by exclusion of other etiologies. Primary syphilis and genital herpes accounted for only 17% and 12% of the cases, respectively. Lymphogranuloma venereum was found in 13% of the patients, and in 15% of cases no diagnosis was made.

Chancroid↗
PubMedDate not supplied

Accuracy of clinical diagnosis of genital ulcer disease.

In Africa, establishment of an accurate clinical diagnosis in cases of genital ulcer disease is difficult owing to atypical presentation of ulcerations and mixed infections. This is compounded by the frequent lack of suitable laboratory facilities. In 240 cases of genital ulcer disease among mineworkers in Carletonville, South Africa, this study endeavored to correlate the clinical diagnosis with laboratory findings. Clinical accuracy and positive and negative predictive values were determined for each type of genital ulcer disease encountered. Overall, the accuracy of clinical diagnosis was 68% for single infections, 80% for chancroid, 55% for primary syphilis, 27% for lymphogranuloma venereum (LGV), and 22% for genital herpes. Adequate laboratory facilities are indispensible for the establishment of an accurate etiologic diagnosis of genital ulcer disease and thus the institution of appropriate antimicrobial therapy.

Chancroid↗
PubMedDate not supplied

Transport media for Haemophilus ducreyi.

Stuart's, Amies' and four thioglycollate/hemin-based media containing, respectively, selenium dioxide and albumin (SA); selenium dioxide, L-glutamine and albumin (SGA); selenium dioxide and L-glutamine (SG); and L-glutamine and albumin (GA); were evaluated as transport media for Haemophilus ducreyi in a simulated, laboratory-based study. No transport medium was able to maintain the viability of H. ducreyi for more than 24 hours at room temperature. Amies' transport medium, however, maintained viability of H. ducreyi for up to 3 days and all the newly formulated transport media maintained viability of H. ducreyi for more than 4 days at 4 degrees C. Subsequently, swabs were taken from cases of genital ulcerations with a diagnosis of chancroid, plated directly onto selective media, and held at 4 degrees C in the two most efficient transport media (SGA and GA) for various periods of time. On direct plating, H. ducreyi was recovered from the genital ulcerations of 110 of 156 (71%) patients. The rates of recovery of H. ducreyi from transport media stored at 4 degrees C decreased with time. Although recovery was enhanced at day 4 (117/110 [106%]) using both SGA and GA, a recovery rate of 37/41 (90%) was obtained after storage in GA for 1 week.

Chancroid↗
PubMedDate not supplied

The suppressive effect of serum samples from patients with chancroid on human mononuclear cells correlates with the clinical picture and is interleukin-2-dependent.

Plasma samples from patients with chancroid diagnosed both on clinical and microbiological grounds were assessed for their ability to inhibit mitogen-induced proliferation of human lymphocytes from healthy donors. All serum samples analysed suppressed phytohaemagglutinin A (PHA) blastogenic response. A significant difference in the observed extent was seen when serum samples from patients with and without associated lymphadenopathy were compared (P < 0.05). Using an interleukin-2 (IL-2)-dependent cell line it could be demonstrated that the addition of patients' plasma to cultured cells markedly depressed mitogen-induced IL-2 synthesis. Results presented suggest that cell-mediated mechanisms play a role in the pathogenesis of infection due to Haemophilus ducreyi.

Cell Line↗
PubMedDate not supplied

Isolation of Mycoplasma hominis from genital ulcerations of patients in Eastern and Southern Africa.

In three separate surveys involving 413 patients in Mbabane (Swaziland), Nairobi (Kenya), and Carletonville (South Africa), Mycoplasma hominis was isolated from the base of ulcers in 41 (16%) of 251 men with genital ulcer disease. Antibodies to M. hominis were detected by indirect hemagglutination in 89 (51%) of 176 such patients. Of these male patients, 15% and 6% had indirect hemagglutinating antibodies at titers of greater than or equal to 160 and greater than or equal to 640, respectively. The rate of isolation of M. hominis and the results of serologic tests for antibodies to this organism were the same whether or not a cause of genital ulcer disease was identified.

Antibodies, Bacterial↗