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Biomedical subjects

A Vernon

Publications and source records attributed to A Vernon.

14 recordsLinked to original sources
PubMed2001

Duration of efficacy of treatment of latent tuberculosis infection in HIV-infected adults.

BACKGROUND: Treatment of latent infection is needed to protect HIV-infected individuals against tuberculosis. A previous report addressed short-term efficacy of three regimens in HIV-infected adults. We now report on long-term efficacy of the study regimens. METHODS: Three daily self-administered regimens were compared in a randomized placebo-controlled trial in 2736 purified protein derivative (PPD)-positive and anergic HIV-infected adults. PPD-positive subjects were treated with isoniazid (INH) for 6 months (6H), INH plus rifampicin for 3 months (3HR), INH plus rifampicin and pyrazinamide for 3 months (3HRZ), or placebo for 6 months. Anergic subjects were randomized to 6H or placebo. RESULTS: 6H initially protected against tuberculosis in PPD-positive individuals; however, benefit was lost within the first year of treatment. Sustained benefit was observed in persons receiving 3HR and 3HRZ. In a Cox regression analysis, the adjusted relative risk for tuberculosis compared with placebo was 0.67 [95% confidence interval (CI), 0.42-1.07] for 6H, 0.49 (95% CI, 0.29-0.82) for 3HR, and 0.41 (95% CI, 0.22-0.76) for 3HRZ. When the rifampicin-containing regimens were combined, the adjusted relative risk for tuberculosis compared with placebo was 0.46 (95% CI, 0.29-0.71). Among anergic subjects, a modest degree of protection with 6H was present (adjusted relative risk, 0.61; 95% CI, 0.32-1.16). Treatment of latent tuberculosis infection had no effect on mortality. CONCLUSION: Six months of INH provided short-term protection against tuberculosis in PPD-positive HIV-infected adults. Three month regimens including INH plus rifampicin or INH, rifampicin and pyrazinamide provided sustained protection for up to 3 years.

AIDS-Related Opportunistic Infections↗
PubMed2001

Effectiveness of once-weekly rifapentine and moxifloxacin regimens against Mycobacterium tuberculosis in mice.

Mice infected with 1.6 x 10(7) CFU of Mycobacterium tuberculosis were treated 14 days later for 6 months with a regimen of once-weekly 10 mg of rifapentine and 75 mg of isoniazid per kg of body weight supplemented with either 150 mg of streptomycin per kg or 100 mg of moxifloxacin per kg during either both the 2-week daily initial and once-weekly continuation phases or only in the daily 2-week initial phase. On completion of treatment, all lung cultures were negative, except for three mice, each with a single colony: two whose rifapentine-isoniazid regimen was supplemented with streptomycin during the whole course of therapy and one whose rifapentine-isoniazid regimen had no initial daily phase, but was supplemented with streptomycin and moxifloxacin during the whole course of therapy. After 3 months of follow-up, positive lung cultures were obtained from 61 and 56% of mice supplemented with streptomycin during either the full course of therapy or only the daily 2-week initial phase, respectively, and 15 and 50% of mice supplemented with moxifloxacin during either the full course of therapy or only the daily 2-week initial phase, respectively. These results suggest that moxifloxacin has sterilizing activity against M. tuberculosis.

Animals↗
PubMed2000

Antituberculosis activity of once-weekly rifapentine-containing regimens in mice. Long-term effectiveness with 6- and 8-month treatment regimens.

The effectiveness of various once-weekly 10 mg/kg rifapentine (P)- containing regimens for treatment of tuberculosis was assessed in mice infected intravenously with 4.3 x 10(6) colony-forming units (cfu) of Mycobacterium tuberculosis H37Rv, and treated 14 d later with various combinations of rifampin (R), P, isoniazid (H), pyrazinamide (Z), ethambutol (E), or streptomycin (S). Control mice treated daily with either 2-mo HRZ + 4-mo HR or 2-mo HRZ + 6-mo HE were rendered spleen and lung culture-negative at 6 mo and 8 mo, respectively. Treatment failure with emergence of R-resistant bacilli occurred in all mice given once-weekly monotherapy with P for 6 mo. Once-weekly PH treatment was successful at 6 mo when it was preceded by a 2-mo daily phase with HRZ. When the initial daily phase was reduced to 2 wk, once-weekly PH-containing treatment was successful, at 6 mo, only if it was supplemented with S during the initial daily and the once-weekly phases, and at 8 mo if it was supplemented with daily H during the once-weekly phase. Without these supplements, once-weekly treatment failed in some mice with selection of R-resistant or H-resistant mutants.

Animals↗
PubMed1999

Acquired rifamycin monoresistance in patients with HIV-related tuberculosis treated with once-weekly rifapentine and isoniazid. Tuberculosis Trials Consortium.

BACKGROUND: Rifapentine is a cyclopentyl-substituted rifamycin whose serum half-life is five times that of rifampin. The US Public Health Service Study 22 compared a once-weekly regimen of isoniazid and rifapentine with twice weekly isoniazid and rifampin in the continuation phase (the last 4 months) of treatment for pulmonary tuberculosis in HIV-seropositive and HIV-seronegative patients. This report concerns only the HIV-seropositive part of the trial, which has ended. The HIV-seronegative part will stop follow-up in 2001. METHODS: Adults with culture-positive, drug-susceptible pulmonary tuberculosis who completed 2 months of four-drug (isoniazid, rifampin, pyrazinamide, ethambutol) treatment (induction phase) were randomly assigned 900 mg isoniazid and 600 mg rifapentine once weekly, or 900 mg isoniazid and 600 mg rifampin twice weekly. All therapy was directly observed. Statistical analysis used univariate, Kaplan-Meier, and logistic and proportional hazards regression methods. FINDINGS: 71 HIV-seropositive patients were enrolled: 61 completed therapy and were assessed for relapse. Five of 30 patients in the once-weekly isoniazid/rifapentine group relapsed, compared with three of 31 patients in the twice-weekly isoniazid/rifampin group (log rank chi2=0.69, p=0.41). However, four of five relapses in the once-weekly isoniazid/rifapentine group had monoresistance to rifamycin, compared with none of three in the rifampin group (p=0.05). Patients who relapsed with rifamycin monoresistance were younger (median age 29 vs 41 years), had lower baseline CD4 cell counts (median 16 vs 144 microL), and were more likely to have extrapulmonary involvement (75% vs 18%, p=0.03) and concomitant therapy with antifungal agents (75% vs 9%, p=0.006). No rifamycin monoresistant relapse has occurred among 1004 HIV-seronegative patients enrolled to date. INTERPRETATION: Relapse with rifamycin monoresistant tuberculosis occurred among HIV-seropositive tuberculosis patients treated with a once-weekly isoniazid/rifapentine continuation-phase regimen. Until more effective regimens have been identified and assessed in clinical trials, HIV-seropositive people with tuberculosis should not be treated with a once-weekly isoniazid/rifapentine regimen.

AIDS-Related Opportunistic Infections↗
PubMed1994

Quality of sexually transmitted disease services in Jamaica: evaluation of a clinic-based approach. Collaborative Working Group on Indicators of STD Case Management.

As part of a larger strategy to develop global indicators of HIV (human immunodeficiency virus) infection prevention programmes, a clinic-based method for the assessment of sexually transmitted disease (STD) service quality was developed and field tested by trained observers who visited a random sample of public-sector clinics in Jamaica in October 1991. The assessment included an inventory of equipment and drugs, interviews with clinic staff, and observations of 27 health workers in 15 clinics as they provided services to 115 patients presenting for STD care. This observation-based method provided Jamaican programme managers with descriptive data on STD case management in public clinics within a one-month study period at an approximate local cost of US+ 5000. Based on weighted estimates, 91% of public-sector STD patients in Jamaica were seen in clinics whose staff had received some training in STD case management during the preceding 12 months. The correct treatment rate was estimated to be 82% for those diagnosed with gonorrhoea, and 70% for those diagnosed with syphilis. Based on 98 observed encounters for first-time-for-episode patients, counselling included sex partner referral (57%), partner reduction (48%), and condom use (59%). Although 61% of STD patients were seen in clinics with condoms in stock on the day of the assessment, only 23% were offered condoms during their visit. The clinic-based assessment method can be adapted to the programme management and reporting needs of countries at all stages of STD service development, and can provide data needed to improve programme operations and meet international reporting standards.

Adolescent↗
PubMed1993

The effect of US preexposure on conditioned taste aversion: lack of postconditioning recovery of the aversion.

Although the CS preexposure effect in CTA was once viewed exclusively as an acquisition failure, recent studies have suggested that the latent inhibition phenomenon is the result of retrieval impairment. This interpretive challenge is based on the unexpected finding that recovery of the aversion occurs over a long retention interval following conditioning (Kraemer, Lariviere, & Spear, Animal Learning and Behavior, 16, 185-190, 1988; Bakner, Strohen, Nordeen, & Riccio, Physiology & Behavior, 50, 1269-1272, 1991). This study examined whether a similar recovery occurs after US preexposure. Following preexposure to the US (LiCl), rats received a sucrose-illness pairing and were subsequently tested after either short or long training-to-test intervals. In contrast to the findings with the CS preexposure effect, US-preexposed subjects did not show a spontaneous increase in CTA following the long retention interval.

Animals↗
PubMed1991

Split-mixed insulin regimen with human ultralente before supper and NPH (isophane) before breakfast in children and adolescents with IDDM.

OBJECTIVE: Fasting hyperglycemia is common in patients with insulin-dependent diabetes mellitus (IDDM) treated with twice-daily subcutaneous insulin regimens. We postulated that substituting human ultralente insulin for the presupper dose of intermediate-acting insulin would improve overnight glycemic control in children and adolescents with IDDM. RESEARCH DESIGN AND METHODS: This 6-mo double-blind crossover study compared a conventional insulin regimen, a mixture of human NPH and regular given before both breakfast and supper (NPH), with a novel twice-daily regimen in which human ultralente replaced NPH before the evening meal (ultralente). This study was comprised of 20 children and adolescents (mean age and duration of IDDM 11.3 +/- 2.9 and 2.4 +/- 1.3 yr, respectively) from the Youth Clinic of the Joslin Diabetes Center, all of whom regularly performed self-monitoring of blood glucose (SMBG) and had been treated exclusively with human insulin (mean daily dose 0.75 +/- 0.22 U/kg). Subjects performed SMBG on a prescribed schedule with a glucose meter with an electronic memory, and recorded results of blood glucose measurements, insulin dosages, and episodes of hypoglycemia. Monthly measurements were obtained for height, weight, and HbA1, and mean daily insulin dosages and average blood glucose level before breakfast, lunch, supper, bedtime snack, and between 0200 and 0300 were calculated. Nonfasting serum lipids were measured at entry, crossover, and the end of the study. RESULTS: After 3 mo, mean HbA, did not differ significantly (9.1 +/- 1.7 vs. 9.5 +/- 1.4%, NPH and ultralente, respectively). Mean fasting blood glucose was significantly lower on ultralente (9.6 +/- 1.9 vs. 10.3 +/- 2.2 mM, P less than 0.05, and blood glucose showed a similar trend (0.05 less than P less than 0.1) before lunch (8.9 +/- 1.7 vs. 9.8 +/- 2.6 mM. Mean blood glucose before bedtime snack was significantly lower (P less than 0.01) on NPH (8.4 +/- 1.9 vs. 10.0 +/- 2.1 mM) but did not differ significantly before supper or between 0200 and 0300. On the two regimens, growth and serum lipids were normal and similar, and no differences were observed in the incidence or severity of hypoglycemia. CONCLUSIONS: Compared with a mixed dose of regular and NPH, a similar dose of a mixture of regular and human ultralente insulin before supper caused a modest reduction in fasting blood glucose levels but was associated with higher blood glucose levels before the bedtime snack. Overall glycemic control, reflected in HbA1 values, was not significantly improved.

Child↗
PubMed1990

Acute gastrointestinal illness and child care arrangements.

This study uses data from the 1981 National Health Interview and the 1981 Child Health Supplement to assess the extent to which family day care homes and child care centers pose a risk of acute gastrointestinal illness among preschool children. The study uses a nationally representative sample of children 0-5 years of age (n = 4,845). Acute gastrointestinal illness was identified from parental reports of acute illness in a 2-week period. Information on type and duration of child care, as well as a variety of sociodemographic and environmental factors (e.g., crowding, seasonality), were obtained. The authors hypothesize that risk of acute gastrointestinal illness would vary by group size. Center attendees were thought to have the greatest exposure to infectious agents, followed by children in day care homes, and lastly by those receiving care in their own homes. Risk models were estimated separately for children less than 3 years of age and for children aged 3-5 years. Our results show that an elevated risk of acute gastrointestinal illness associated with child care is confined to children less than 3 years of age who regularly attend centers/nursery schools (odds ratio = 3.49, 95% confidence interval 0.99-4.77), controlling for other confounding variables. For children aged 3-5 years, low socioeconomic status, poverty, and seasonality are stronger predictors of acute gastrointestinal illness than is center care. Family day care appears to be unrelated to the risk of illness for both age groups.

Acute Disease↗
PubMed1988

Prevalence of enteric pathogens in homosexual men with and without acquired immunodeficiency syndrome.

We studied 388 homosexual or bisexual men from the Baltimore-Washington area to define the spectrum of enteric pathogen carriage in a population at high risk for "gay bowel syndrome" in association with human immunodeficiency virus infection. Seventy-seven patients with acquired immunodeficiency syndrome, 68 gay men with symptoms of acute diarrhea or proctitis, and 243 gay men without gastrointestinal symptoms and participating in a natural history study of human immunodeficiency virus infection were selected for study. Approximately 12% of the asymptomatic men harbored at least one enteric pathogen; the most frequently recovered were Chlamydia trachomatis, herpes simplex virus, and Giardia lamblia. Men carrying a pathogen were more likely to be human immunodeficiency virus seropositive (48%) than men without a pathogen (25%) (p = 0.018), more likely to have fewer T helper cells (p = 0.015), and more likely to have a mucopurulent exudate (p = 0.014). We recovered an agent of enteric disease from 68% of gay men presenting with diarrhea or proctitis. Campylobacter species, herpes simplex virus, Neisseria gonorrhoeae, C. trachomatis, G. lamblia, and Shigella species were identified most frequently. The most common pathogen associated with diarrhea in acquired immunodeficiency syndrome was Cryptosporidium (16% of 49 cases). Other agents identified were Clostridium difficile, Vibrio parahemolyticus, Campylobacter species, G. lamblia, Isospora, and cytomegalovirus. Approximately half of the identifiable etiologic agents of diarrhea in acquired immunodeficiency syndrome patients were treatable with antibiotics, but these agents required special culture procedures for detection.

Acquired Immunodeficiency Syndrome↗
PubMed1987

AIDS wrongly diagnosed.

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Acquired Immunodeficiency Syndrome↗
PubMed1975

Renal excretion of fluoride in renal failure and after renal transplantation.

We have compared the renal excretion of fluoride in a variety of patients with chronic renal failure maintained with and without protein restriction before and during regular dialysis treatment and after transplantation. The patients tended to continue to excrete normal dietary loads of fluoride quite well until renal function was seriously reduced. From a regression of function on excretion the mean level of creatinine clearance when a normal dietary load of fluoride 0.0526 plus or minus 0.019 mmol/2 h (1.0 plus or minus 0.36 mg/24h) has a 90% chance of being excreted lies around 16 ml/min, a level when most patients with renal failure will be symptomatic. Acute loading of such patients with additional fluoride in the form of sodium fluoride from 40 mg to 60 mg/day showed a twofold to threefold increase of serum fluoride concentrations, slight increases in urinary fluoride excretion, and heavy tissue absorption, suggesting that prior fluoride loading of the skeleton had not taken place. These effects contrasted with those in one patient with normal renal function and with those in one patient with skeletal saturation due to prolonged loading. After renal transplantation fluoride excretion increased but reached normal levels within three months of satisfactory function, suggesting that fluoride loading in renal failure and during regular dialysis therapy had not been excessive.

Calcium↗
PubMed1975

Testicular scanning: a new modality for the preoperative diagnosis of testicular torsion.

A simple, safe and rapid scanning procedure using 99-m technetium is described for the diagnosis of torsion of testicles. The procedure is especially useful in the adult with an enlarged scrotum of recent origin in whom the surgeon cannot clinically differentiate torsion of the testicle from epididmitis. It is not suggested that this procedure replace immediate scrotal exploration in the acutely illpatient.

Adolescent↗