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Biomedical subjects

R Ballard

Publications and source records attributed to R Ballard.

At least 19 recordsLinked to original sources
PubMed2000

Evidence of declining STD prevalence in a South African mining community following a core-group intervention.

OBJECTIVES: To reduce the prevalence of curable sexually transmitted diseases (STDs) in a South African mining community through provision of STD treatment services, including periodic presumptive treatment and prevention education to a core group of high-risk women living in areas around the mines. METHODS: Women at high risk for STDs attended a mobile clinic monthly for examination and counseling, and were treated presumptively for bacterial STDs with a directly observed 1-g dose of azithromycin. Gonococcal and chlamydial infection rates were measured by urine ligase chain reaction, and genital ulcers were assessed by clinical examination. Changes in STD prevalence among local miners were assessed through comparison of prevalence in two cross-sectional samples of miners taken 9 months apart, and through routine disease surveillance at mine health facilities. RESULTS: During the first 9 months of the intervention, 407 women used the services. Baseline prevalence of Neisseria gonorrhoeae and/or Chlamydia trachomatis in women was 24.9%; 9.7% of these women had clinical evidence of genital ulcer disease (GUD). The proportion of women with incident gonococcal or chlamydial infections at the first monthly return visit (69% follow-up rate) was 12.3%, and genital ulcers were found in 4.4% of these women. In the miner population, the prevalence of N gonorrhoeae and/or C trachomatis was 10.9% at baseline and 6.2% at the 9-month follow-up examination (P<0.001). The prevalence of GUD by clinical examination was 5.8% at baseline and 1.3% at follow-up examination (P< 0.001). Rates of symptomatic STDs seen at mine health facilities decreased among miners in the intervention area compared with miners living farther from the site and with less exposure to the project. DISCUSSION: Provision of STD treatment services to a core group of high-risk women may significantly reduce their burden of disease, and may contribute to a reduction in community STD prevalence. In the absence of sensitive and affordable screening tests for STDs in women, periodic presumptive treatment coupled with prevention education is a feasible approach to providing STD services in this population.

Adult↗
PubMed1998

A multidisciplinary approach to hemodialysis access: prospective evaluation.

Dialysis access procedures and complications represent a major cause of morbidity, hospitalization and cost for chronic dialysis patients. To improve outcomes and reduce the cost of hemodialysis access procedures we developed a multidisciplinary approach, involving nephrologists, access surgeons, and radiologists. A full-time dialysis access coordinator scheduled all access procedures with the surgeons and radiologists, and tracked outcomes. A computerized database was developed for prospective documentation of procedures and complications. Confidential, detailed analyses and recommendations for improvements were provided periodically to the surgeons and radiologists. The major changes arising from the multidisciplinary approach were as follows: (1) The approach to clotted grafts evolved from an inpatient surgical procedure to an outpatient radiologic procedure. The immediate technical success rate of graft declots increased from 48% to 69%. (2) Elective placement of arteriovenous (A-V) grafts evolved from a three-day inpatient hospitalization to a largely outpatient procedure. The proportion of A-V grafts placed as same day surgery or outpatient surgery increased from 16% to 81%. (3) Surgical complications of new A-V graft surgery decreased from 25% to 11%. (4) Aggressive detection and correction of graft stenosis decreased the incidence of graft thrombosis by 60%, from 0.70 to 0.28 events per patient-year. (5) The proportion of native A-V fistula construction in new dialysis patients increased from 33% to 69%. In conclusion, an integrated multidisciplinary approach markedly reduced surgical complications of access surgery and decreased access failures. These improvements occurred despite a marked decrease in hospitalization for access procedures, with a substantial cost saving.

Aged↗
PubMed1998

The rrs (16S)-rrl (23S) ribosomal intergenic spacer region as a target for the detection of Haemophilus ducreyi by a heminested-PCR assay.

The intergenic spacer region between the rrs and rrl ribosomal RNA genes of Haemophilus ducreyi was analysed and the DNA sequence was used for the selection of specific PCR primers. A highly sensitive and specific heminested-PCR assay for the identification of H. ducreyi was developed. The assay showed a sensitivity of 96% on genital ulcer specimens from patients with clinically diagnosed chancroid, compared with a sensitivity of 56% for culture methods. These results indicate that this PCR assay has the potential to become an accurate and easy reference method for the detection of H. ducreyi.

Base Sequence↗
PubMed1998

Potential Alu function: regulation of the activity of double-stranded RNA-activated kinase PKR.

Cell stress, viral infection, and translational inhibition increase the abundance of human Alu RNA, suggesting that the level of these transcripts is sensitive to the translational state of the cell. To determine whether Alu RNA functions in translational homeostasis, we investigated its role in the regulation of double-stranded RNA-activated kinase PKR. We found that overexpression of Alu RNA by cotransient transfection increased the expression of a reporter construct, which is consistent with an inhibitory effect on PKR. Alu RNA formed stable, discrete complexes with PKR in vitro, bound PKR in vivo, and antagonized PKR activation both in vitro and in vivo. Alu RNAs produced by either overexpression or exposure of cells to heat shock bound PKR, whereas transiently overexpressed Alu RNA antagonized virus-induced activation of PKR in vivo. Cycloheximide treatment of cells decreased PKR activity, coincident with an increase in Alu RNA. These observations suggest that the increased levels of Alu RNAs caused by cellular exposure to different stresses regulate protein synthesis by antagonizing PKR activation. This provides a functional role for mammalian short interspersed elements, prototypical junk DNA.

Cell Line↗
PubMed1997

On-site HIV testing in resource-poor settings: is one rapid test enough?

OBJECTIVE: To determine the feasibility, accuracy and cost-effectiveness of a rapid, on-site, HIV testing strategy in a rural hospital, and to assess its impact on test turnaround time and the proportion of patients post-test counselled. DESIGN: Prospective comparison of two testing strategies [double rapid test on-site versus central enzyme-linked immunosorbent assay (ELISA)-based testing], and an economic evaluation. SETTING: Hlabisa Hospital, a rural South African district hospital. PATIENTS: A total of 454 consecutive adult inpatients requiring and consenting to HIV testing as part of their clinical management. MAIN OUTCOME MEASURES: Concordance between rapid tests, and between the rapid and ELISA strategies, test turnaround time, proportion of patients post-test counselled, and cost-effectiveness. RESULTS: HIV seroprevalence was 49.6%. Both rapid tests were concordant in all patients [one-sided 95% confidence interval (CI) of probability, 99.3-100]. The rapid strategy was 100% sensitive (95% CI, 97.9-100) and 99.6% specific (95% CI, 97.2-100) compared with the ELISA strategy. The mean interval between ordering a test and post-test counselling fell from 21 days prior to the introduction of the rapid test strategy to 4.6 days after its introduction (P < 0.00001). The proportion of patients post-test counselled increased to 96% from 17% after the introduction of the rapid test strategy (P < 0.00001). By using a double rapid test strategy the cost per patient post-test counselled was almost halved to US$ 11. Accuracy of the rapid strategy was not substantially increased by performing two tests. CONCLUSION: In high prevalence, resource-poor settings, rapid, on-site HIV testing is feasible, accurate and highly cost-effective, substantially increasing the number of patients post-test counselled. A single rapid test may be sufficient.

AIDS Serodiagnosis↗
PubMed1996

A three year outcome evaluation of a theory based drink driving education program.

This study reports on the impact of a "drink driving education program" taught to grade ten high school students. The program which involves twelve lessons uses strategies based on the Ajzen and Madden theory of planned behavior. Students were trained to use alternatives to drink driving and passenger behaviors. One thousand seven hundred and seventy-four students who had been taught the program in randomly assigned control and intervention schools were followed up three years later. There had been a major reduction in drink driving behaviors in both intervention and control students. In addition to this cohort change there was a trend toward reduced drink driving in the intervention group and a significant reduction in passenger behavior in this group. Readiness to use alternatives suggested that the major impact of the program was on students who were experimenting with the behavior at the time the program was taught. The program seems to have optimized concurrent social attitude and behavior change.

Adolescent↗
PubMed1995

Intramuscular pressure and torque during isometric, concentric and eccentric muscular activity.

Intramuscular pressures, electromyography (EMG) and torque generation during isometric, concentric and eccentric maximal isokinetic muscle activity were recorded in 10 healthy volunteers. Pressure and EMG activity were continuously and simultaneously measured side by side in the tibialis anterior and soleus muscles. Ankle joint torque and position were monitored continuously by an isokinetic dynamometer during plantar flexion and dorsiflexion of the foot. The increased force generation during eccentric muscular activity, compared with other muscular activity, was not accompanied by higher intramuscular pressure. Thus, this study demonstrated that eccentric muscular activity generated higher torque values for each increment of intramuscular pressure. Intramuscular pressures during antagonistic co-activation were significantly higher in the tibilis anterior muscle (42-46% of maximal agonistic activity) compared with the soleus muscle (12-29% of maximal agonistic activity) and was largely due to active recruitment of muscle fibers. In summary, eccentric muscular activity creates higher torque values with no additional increase of the intramuscular pressure compared with concentric and isometric muscular activity.

Adult↗
PubMed1994

The Chédiak-Higashi syndrome: CT and MR findings.

Chédiak-Higashi syndrome (CHS) is a rare autosomal recessive disorder postulated to result from lack of regulation of fusion of the primary lysosomes. In this report we present the MR and CT features of the brain in a patient with known CHS. These findings include diffuse atrophy of the brain with diffuse periventricular decreased density identified with CT, as well as increased signal on the T2-weighted images and lack of enhancement on the T1-weighted images in the periventricular and corona radiata regions.

Atrophy↗
PubMed1993

Antimicrobial susceptibilities and serotyping of Neisseria gonorrhoeae in southern Africa: influence of geographical source of infection.

One hundred and ninety-two strains of Neisseria gonorrhoeae isolated from migrant mine-workers were tested for their susceptibility to antibiotics, auxotyped and serotyped. Of the total, 93 (48%) were acquired locally and 64 (33%) from different geographical locations. Plasmid-mediated resistance to penicillin was found in 28 (14.6%) strains and was associated predominantly with the presence of 5.0 kb penicillinase encoding plasmid (18/28, 64%). Chromosomal resistance to penicillin (MIC > or = 1 mg/l) was detected in 14 (7.3%) strains. Resistance to tetracycline was chromosomally and not plasmid-mediated. Antibiotic resistance was encountered most commonly among strains acquired in Natal. The overall gonococcal population was sensitive to ceftriaxone, ciprofloxacin, spectinomycin and azithromycin. Nine auxotype/serovar (A/S) classes were encountered among penicillinase-producing N. gonorrhoeae (PPNG) compared to 24 A/S classes among non-PPNG strains. The most common A/S class was NR/IA-6 which accounted for 38% of PPNG and 15% of non-PPNG.

Africa, Southern↗
PubMed1993

Progressive massive fibrosis associated with idiopathic pulmonary hemosiderosis.

Progressive massive fibrosis is a recognized complication of pneumoconiosis secondary to pulmonary fibrosis, with retraction forming conglomerate masses symmetrically in the upper lobes. Idiopathic pulmonary hemosiderosis is known to cause pulmonary fibrosis secondary to recurrent alveolar hemorrhage with deposition of hemosiderin in the interstitium. We present a case in which progressive massive fibrosis developed in a patient with long-standing idiopathic pulmonary hemosiderosis.

Female↗
PubMed1992

Short forms of the Marlowe-Crowne Social Desirability Scale.

Three short forms of the Marlowe-Crowne Social Desirability Scale were constructed from the results of principal components analysis (N = 399). Those subscales were compared with short forms developed by previous researchers who used the same methodology. Examination of the subscales indicated that 13 of the scale's 33 items were isolated by at least two of the three reported studies. Those items were used to construct a composite subscale, which appeared to offer a useful alternative to the full scale. Further analysis of the subscale's contents, however, raised questions about the dimensionality of the Marlowe-Crowne scale. Caution was urged in the use and interpretation of both the full inventory and the short form until the meaning of scale scores can be clarified.

Bias↗
PubMed1991

Recombinant human erythropoietin in the anemia of prematurity: results of a placebo-controlled pilot study.

Experimental and clinical data implicate inadequate erythropoietin production as an important reason that infants acquire this anemia and suggest that recombinant human erythropoietin (r-HuEPO) might be used to treat or prevent it. We therefore randomly assigned 20 small premature infants (birth weight less than or equal to 1250 gm) who were highly likely to require erythrocyte transfusions for anemia of prematurity to receive 6 weeks of treatment with either intravenously administered r-HuEPO (at a dose of 100 units/kg twice each week) or a placebo. Hematologic measurements, transfusion requirements, and growth were followed during therapy and for 6 months thereafter. Treated (EPO) and control babies did not differ with respect to weight, hematocrit, overall mean absolute reticulocyte count, calculated erythrocyte mass, or rate of growth. However, reticulocyte counts increased earlier in patients given r-HuEPO. Six of ten babies in the EPO group, and 8 of 10 assigned to the control group, received at least one erythrocyte transfusion during treatment. For all infants the amount of blood sampled for laboratory tests was strongly predictive of the volume of packed erythrocytes transfused (r = 0.890; p = 0.0001). Of nine infants who had less than 20 ml packed erythrocytes removed for laboratory tests, none of four given r-HuEPO received a transfusion, whereas three of five infants assigned to the placebo group received one. No toxic effects were attributable to r-HuEPO, and no significant changes in leukocyte or platelet counts occurred during treatment. Reticulocyte counts were correlated with simultaneous platelet counts and were inversely related to absolute neutrophil counts in both study groups. We conclude that r-HuEPO administration is safe and feasible at the dose studied. Additional controlled trials utilizing higher doses of r-HuEPO and larger numbers of patients are justified.

Anemia, Neonatal↗
PubMed1989

Hypoxic-reperfusion injury in the inflamed human joint.

A series of experiments showed that, on exercise of the inflamed human knee, intra-articular pressure rises above synovial capillary perfusion pressure, causing intra-articular hypoxia; and that, on cessation of exercise, there is oxidative damage to lipids and IgG within the joint. These findings are consistent with the hypothesis that persistence of synovial inflammation can be due to exercise-induced hypoxic-reperfusion injury mediated by reactive oxygen species.

Adult↗
PubMed1988

Changes in the activity of skeletal muscle calcium-activated neutral proteinase (EC 3.4.22.17) and its specific inhibitor in chickens grown at different rates in response to graded levels of dietary protein.

1. Two experiments are reported in which the effect of alteration in growth rate on the levels of avian skeletal muscle calcium-activated neutral proteinase (EC 3.4.22.17) (CANP or calpain) and its specific inhibitor (calpastatin), a system thought to be implicated in myofibrillar catabolism, was studied by means of manipulation of dietary protein concentration. 2. In Expt 1 broiler chicks were given free access to diets containing 105, 149, 197 and 212 g protein/kg for 20 d. In Expt 2 the four dietary treatments were 119, 141, 182 and 227 g protein/kg diet given for 16 d. Chick growth rate and total leg skeletal muscle weight significantly increased (P less than 0.001) with increasing dietary protein concentration in both experiments. Total skeletal muscle protein increased with the level of dietary protein, the effect being significant (P less than 0.01 and P less than 0.001 in Expts 1 and 2 respectively). 3. Minced leg muscle was homogenized in low-salt buffers, and the extract chromatographed on DEAE-cellulose to separate proteinase and inhibitor activity. The partially purified CANP enzyme and inhibitor proteins were present at a concentration broadly consistent with literature reports, and their elution characteristics and Ca2+ concentration dependence were not varied by dietary protein concentration. 4. Both the muscle CANP and CANP inhibitor activities (units/kg muscle) exhibited upward trends with growth rate and increased muscle weight. However, these differences were not statistically significant (P greater than 0.05) and were not present at all when the results were expressed as units/g muscle protein.

Animals↗