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Biomedical subjects

J M Risser

Publications and source records attributed to J M Risser.

At least 19 recordsLinked to original sources
PubMed2001

Implementation of a screening program for chlamydial infection in incarcerated adolescents.

BACKGROUND: In collaboration with the Houston Department of Health and Human Services, the authors implemented and evaluated a urine-based chlamydia screening program in incarcerated youth in Harris County, Texas, and assessed predictor variables for infection. GOAL: To implement and evaluate chlamydia screening in incarcerated youth. STUDY DESIGN: The authors determined prevalence of chlamydial infection, treatment rates, and predictor variables in 589 youth and repeated the measures 6 months later in 975 additional youth. RESULTS: Initially, the prevalence of infection was 9.6% in males and 28.1% in females; 88% of infected youth were treated while incarcerated. White males had a significantly lower prevalence of chlamydial infection; however, consistent condom use was not associated with a lower prevalence of chlamydia. In the 6-month assessment of chlamydia prevalence in 975 youth, prevalence and treatment rates remained high and predictor variables were similar. CONCLUSION: The authors instituted a screening program for chlamydial infection in incarcerated youth that was performing well at reassessment 6 months later.

Adolescent↗
PubMed1999

Weight change in adolescents who used hormonal contraception.

PURPOSE: (a) To compare weight change at 1 year between adolescents 13-19 years old who were using either depot medroxyprogesterone acetate (DMPA) or oral contraceptives (OC), and (b) to determine if age, baseline body mass index (BMI), race/ethnicity, or weight gain at 3 months predicted which subjects would gain excessive weight. METHOD: The setting was a Planned Parenthood Teen Clinic with chart review of variables of interest. Excessive weight was defined as weight gain > 10%. RESULTS: Baseline variables were similar in the two groups, except that DMPA users (n = 44) had a greater mean BMI (t test, p = .05) than OC users (n = 86). Mean (standard deviation) and median weight gains at 1 year were 3.0 (4.5) and 2.4 kg in the DMPA users and 1.3 (3.9) and 1.5 kg in the OC users (difference in medians not significant, Wilcoxon rank sum test, p = .10). Fifty-six percent of DMPA and 70% of OC users lost weight or gained < 5% of their baseline weight (p = .17, Fisher exact test); 25% of DMPA users and 7% of OC users gained > 10% of their baseline weight (p = .006). Age, baseline BMI, or race/ethnicity did not affect the likelihood that either group would gain > 5% or > 10% of their baseline weight. Of adolescents who gained > 5% of baseline weight at 3 months, 13 of 14 (93%) gained even more weight at 12 months. CONCLUSIONS: The majority of adolescents who used hormonal contraception for 1 year lost weight or gained < 5% of baseline weight. DMPA users were more likely than OC users to gain > 10%. Subjects who gained > 5% of baseline weight at 3 months were at high risk (93%) of gaining even more weight by 1 year.

Adolescent↗
PubMed1999

The epidemiology of syphilis in the waning years of an epidemic: Houston, Texas, 1991-1997.

BACKGROUND: National and local syphilis rates have fallen since 1990. Accurate epidemiologic information about the distribution of syphilis during the waning years of an epidemic are important to health care organizations so that they can specifically target screening and intervention programs. GOALS: To describe the epidemiology of syphilis in Houston, Texas, from 1991 through 1997. STUDY DESIGN: Descriptive evaluation of morbidity surveillance data from the Houston Department of Health and Human Services. RESULTS: Between 1991 and 1997, rates for syphilis fell 61%. Rates for primary and secondary syphilis fell 90% among men and women in all race/ethnicity groups; early latent rates fell 81% among blacks, 57% among Hispanics, and 50% among whites. Late latent rates were stable among blacks and whites and increased among Hispanics. The proportion of total cases identified as late latent disease increased from 16% in 1991 to 63% in 1997. Congenital syphilis rates have remained at approximately 2 per 1,000 live births since 1993. CONCLUSION: Syphilis continues to be a problem in Houston. The medical community and HIV/STD prevention programs need to be vigilant in actively screening high-risk individuals to identify syphilis at earlier stages of the disease and to prevent congenital syphilis.

Adult↗
PubMed1998

SKF 38393 enhances odor detection performance.

The purpose of this study was to determine the influence of the D1-selective partial agonist SKF 38393 on the odor detection performance of rats using high precision olfactometry and a go/no-go operant task. Previous studies have found that the D2 receptor partial agonist quinpirole decreases such performance, but the influences of D1 receptor activation are unknown. In experiment 1, such detection performance to the odorant ethyl acetate was enhanced by SKF 38393, relative to saline, in male rats at 7.5 and 10.0 mg/kg i.p. dose levels, but not at the lower doses of 1.0, 2.5, and 5.0 mg/kg. In experiment 2, this enhancement was replicated at the 7.5 and 10.0 mg/kg doses and was shown to occur at the 12.5 mg/kg dose as well. In experiment 3, similar enhancement was shown for the odorant eugenol in female rats at the 7.5, 10.0 and 12.5 mg/kg doses, suggesting this effect is neither sex-specific nor confined to the odorant ethyl acetate. In experiment 4, a 0.025 mg/kg dose of the D1 receptor antagonist SCH 23390 depressed the enhancement produced to ethyl acetate by 7.5 mg/kg SKF 38393 to control levels. Overall, these data demonstrate that, in contrast to quinpirole, SKF 38393 improves odor detection performance in the rat and that this phenomenon can be attenuated by the D1 receptor blocker SCH 23390.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1998

A randomized controlled trial evaluating nutrition counseling with or without oral supplementation in malnourished HIV-infected patients.

OBJECTIVE: To evaluate the effects of nutrition counseling with or without oral supplementation in malnourished patients infected with the human immunodeficiency virus (HIV). DESIGN: Randomized controlled trial. SUBJECTS: HIV-infected men (n=118) who were less than 90% of usual weight for height or who had lost more than 10% of body weight. INTERVENTION: Nutrition counseling alone (control group) vs nutrition counseling plus enteral supplementation (supplement group) for 6 weeks. All patients were instructed to consume a diet that exceeded estimated total energy expenditure by 960 kcal/day. MAIN OUTCOME MEASURES: Weight, skinfold thickness, fat-free mass, grip strength, quality of life, and cognitive function (Buschke test). STATISTICAL ANALYSES: Differences in baseline variables and outcomes were evaluated using analysis of variance or the Wilcoxon rank sum test. RESULTS: Ninety-nine men completed at least 4 weeks of treatment, 49 in the supplement group and 50 in the control group. Half the patients in each treatment group achieved at least 80% of their energy target. No differences in weight, skinfold thickness measurements, or quality of life were observed. Compared with the control group, the supplement group had larger increases in fat-free mass and grip strength, although the differences did not reach statistical significance. APPLICATIONS: In the short term, nutrition counseling with or without oral supplementation can achieve a substantial increase in energy intake in about 50% of malnourished HIV-infected patients. Although further study is needed to evaluate long-term effects, these findings suggest that nutrition counseling has an important role in the management of malnourished HIV-infected patients.

Adult↗
PubMed1998

Problems in physician's classification and reporting of congenital syphilis.

The diagnosis of congenital syphilis (CS) in newborns can only be made through a review of the mothers' testing and treatment history and through the infants' clinical and laboratory findings. We describe difficulties in the classification of CS by physicians and the health department during a recent syphilis epidemic. The records of infants identified as potential cases of CS by laboratory testing, discharge diagnosis, or health department records were reviewed by epidemiologists. The reasons for concordance and discordance in classification between the physician and the epidemiologist were determined. Congenital syphilis was identified in 126 infants. Seventeen cases were discordant and 12 cases concordant but the physician's classification was for incorrect reasons. Misclassification occurred because physicians lacked data known to the health department (n=7), health departments lacked data known to the physician (n=1), and physicians misinterpreted the case definition for CS (n=21). Suggestions for improving the diagnosis and reporting of CS are included.

Adult↗
PubMed1996

Odor detection performance in hypothyroid and euthyroid rats.

The influence of hypothyroidism on the odor detection ability of male Long-Evans rats was determined using high-precision olfactometry and a go/no-go operant task. Nonparametric signal detection measures of sensitivity and responsitivity, as well as measures of S+ response latency, the number of aborted trials, and session time were obtained in daily 200-trial test sessions prior to, during, and after 50 days of maintenance on 0.1% propylthiouracil (PTU). Similar determinations were made in control animals. Neither odor detection nor associated nonsensory performance measures were influenced by hypothyroidism. These results suggest that PTU-induced hypothyroidism does not affect the odor detection performance of rats.

Animals↗
PubMed1996

Uncertain clinical significance of duodenal mucosal abnormalities in HIV-infected individuals. Results of a case-control study.

Previous research has described abnormalities of duodenal mucosal morphology in human immunodeficiency virus (HIV)-infected individuals. We wanted to determine the frequency of disturbed villus architecture and investigate its relationship to HIV-related chronic diarrhea. We conducted a case-control study of 120 HIV-infected men, 63 with and 57 without chronic diarrhea. Stools were cultured for bacteria and examined for ova and parasites; esophagogastroduodenoscopy and flexible sigmoidoscopy with mucosal biopsies were performed. Biopsy tissue was examined using light and electron microscopy to detect enteric pathogens and to evaluate mucosal morphology. The mean CD4+ cell count was 143/min3, and enteric pathogens were detected in 56 of 120 men (47%). In approximately half the study sample (57%), duodenal villus architecture was normal; complete villus flattening was not observed. We detected no association between chronic diarrhea and altered villus architecture. Although further study is needed to clarify the pathogenesis of altered duodenal mucosal morphology, our results suggest that the clinical significance of the abnormalities may be small.

Adult↗
PubMed1993

The role of Microsporidia in the pathogenesis of HIV-related chronic diarrhea.

OBJECTIVE: To determine whether infection with Microsporidia leads to diarrhea in patients with human immunodeficiency virus (HIV) infection. DESIGN: Case-control study. SETTING: Primary care outpatient HIV clinic at a Veterans Affairs medical center. PATIENTS: One hundred six HIV-infected men, 55 with and 51 without chronic diarrhea. MEASUREMENTS: Each patient underwent upper endoscopy and flexible sigmoidoscopy to obtain duodenal, rectal, and sigmoid colonic biopsy specimens. At the time of endoscopy, a fresh stool was obtained for culture, ova and parasite assessment, and Cryptosporidium examination. Biopsy tissue was examined using electron microscopy to detect Microsporidia. RESULTS: The microsporidian parasite Enterocytozoon bieneusi was detected in the duodenal biopsy specimens of 31 of 106 men (29%); 24 of 106 men (23%) had other enteric pathogens. No significant difference was observed in the occurrence of microsporidiosis in patients with (18 of 55 [33%]) and without (13 of 51 [25%]) chronic diarrhea (odds ratio, 1.42; 95% CI, 0.61 to 3.31). A similar nonsignificant difference was observed after controlling for CD4 count and other enteric pathogens (odds ratio, 1.66; 95% CI, 0.68 to 4.06). Among patients with microsporidiosis, no difference was observed in the intensity of infection (defined by the presence of few, moderate, or abundant organisms) among cases and controls (P > 0.2). CONCLUSIONS: This is the first report to document the presence of E. bieneusi in HIV-positive patients without gastrointestinal symptoms. No significant difference was observed in the occurrence of E. bieneusi infection in HIV-infected patients with or without chronic diarrhea. Thus, the association between microsporidiosis and diarrhea, if one exists, may not be as strong as is currently believed.

AIDS-Related Opportunistic Infections↗
PubMed1993

A simple clinical staging system that predicts progression to AIDS using CD4 count, oral thrush, and night sweats.

OBJECTIVE: To develop a simple clinical staging system based on CD4 count and clinical variables that predicts progression to AIDS in HIV-infected non-AIDS patients. DESIGN: Retrospective cohort study. SETTING: A primary care outpatient clinic for HIV-infected patients at a VA Medical Center. PATIENTS: One hundred seventy-six HIV-infected non-AIDS patients seen at the Houston VA Special Medicine Clinic between January 1986 and December 1990 and followed for a mean of 22 months. Fifty-four patients (31%) progressed to AIDS during follow-up. MEASUREMENTS: The medical records were reviewed, and data corresponding to the initial (baseline) clinic visit and subsequent six-month visits were extracted. MAIN RESULTS: "Predictive" baseline variables (i.e., those associated with progression to AIDS) were first identified and then examined in Cox proportional hazards modeling. In the final model, CD4 category, oral thrush, and night sweats made significant independent contributions. A three-stage prognostic system was constructed by assigning points to the three variables: CD4 > 500 cells/mm3 = 0; 500 > or = CD4 > or = 200 = 1; CD4 < 200 = 2; presence of oral thrush = 1; presence of night sweats = 1. Stages were assigned as follows: stage I = 0 points, stage II = 1-2 points, and stage III = 3-4 points. The proportions of patients who progressed to AIDS were: stage I, 6/39 (15%); stage II, 31/106 (29%); and stage III, 17/31 (55%). CONCLUSIONS: These results demonstrate that simple, clinically sensible prognostic staging systems that predict progression to AIDS can be constructed using CD4 count and clinical variables.

AIDS-Related Opportunistic Infections↗
PubMed1993

Effect of HIV transmission category and CD4 count on the occurrence of diarrhea in HIV-infected patients.

This study was designed to assess the relative contributions of HIV transmission category and immunodeficiency to the risk of HIV-related diarrhea. We reviewed the medical records of 169 HIV-infected non-AIDS patients seen between 1986 and 1990 at the Houston VA Special Medicine Clinic. The prevalence of diarrhea at any given clinic visit ranged from 3% to 7%. Diarrhea was three times more common in homosexual/bisexual men [odds ratio = 3.0 (1.01-9.53)], and this pattern persisted when stratified by CD4 count. Previous studies have focused mainly on the detection of enteric organisms in patients with HIV-related diarrhea. Studies of the temporal relationships between sexual practices, enteric pathogens, diarrhea, and immunodeficiency are needed to clarify the pathogenesis of HIV-related diarrhea.

Adult↗
PubMed1993

Failure of providers to vaccinate HIV-infected men against hepatitis B: a missed opportunity.

OBJECTIVE: To carry out an audit of hepatitis B immunization practices in an outpatient HIV clinic. METHODS: We reviewed the medical records of all new HIV-infected patients seen between October 1, 1990 and December 31, 1991. RESULTS: The 125 patients were men with a mean age and CD4 count of 43 yr and 240 cells/mm3, respectively. Fourteen percent (14%) of men who showed a clear need for vaccine, having no HBV markers, were not vaccinated by the clinic staff. Further, 16% whose susceptibility to HBV infection was unclear, with anti-HBc as a sole HBV marker, were not evaluated with a booster dose of hepatitis B vaccine in an attempt to elicit an anamnestic response. CONCLUSIONS: In failing to vaccinate or evaluate the 30% of patients without HBsAg or anti-HBs, our providers are missing an important opportunity in preventive medicine. We urge others to examine their own hepatitis B screening and vaccination practices.

Adult↗
PubMed1991

Quality-specific differences in rat taste detection performance as a function of stimulus volume.

Taste detection performance for representatives of the four taste qualities as a function of stimulus volume (5 x 10(-4) to 1 x 1(-1) ml) was examined in rats using high-precision gustometry, computer-controlled operant procedures, nonparametric signal detection measures of sensitivity and responsivity, and blind control procedures. The overall sensitivity index was positively related to stimulus volume (rs = .60), with optimal detection performance attained with a 5 x 10(-3) ml stimulus volume for salty tastants and a 1 x 10(-2) ml stimulus volume for the other taste qualities. The overall responsivity index was inversely related to stimulus volume (rs = -.47), especially for sour and bitter tastants. These results are consistent with prior observations and demonstrate that operant methods using small tastant samples produce sensitive estimates of the rat's taste detection performance and response bias.

Animals↗
PubMed1991

Influence of adrenalectomy on the odor detection performance of rats.

The influence of adrenalectomy (ADX) on the odor detection performance of male Long-Evans rats was assessed using high-precision olfactometry and a go/no-go operant signal detection task. Nonparametric signal detection measures of sensitivity and responsivity, as well as measures of S+ response latency, the number of aborted trials, and session time, were obtained in daily 250-trial test sessions prior to and after adrenalectomy. Four ADX animals were tested using the odorant pyridine, three using the odorant eugenol, and two using the odorant ethyl acetate. Nine other rats served as sham-operated controls. Neither odor detection nor related nonsensory performance measures were influenced by adrenalectomy or sham-operation procedures. These results imply that adrenalectomy has little or no influence on the odor detection performance of the rat.

Adrenal Cortex↗
PubMed1990

Odor memory and odor learning in rats with lesions of the lateral olfactory tract and mediodorsal thalamic nucleus.

Rats with posterior transection of the lateral olfactory tract (LOT), lesions of the mediodorsal thalamic nucleus (MD), or with combined lesions of these structures were tested for retention of a preoperatively learned multiple odor discrimination task, acquisition of 3 simple 2-odor discrimination problems, and reversal of the last problem of the series. Compared to controls, rats with transection of the LOT had no deficits in any task. Those with MD lesions had no deficits in retention but moderate deficits in acquisition of novel odor discriminations and a severe deficit in reversal learning. Rats with combined LOT and MD lesions had no retention of the preoperatively learned task but their performance on the remaining problems was similar to that of rats with only MD lesions. These results suggest that neither the olfactory thalamocortical projections nor those to the periamygdaloid or entorhinal cortex are essential for storage and/or recall of an olfactory procedural memory task. Performance on the postoperative acquisition tests indicate that the thalamocortical but not the limbic olfactory projections play an important role in olfactory discrimination learning.

Animals↗
PubMed1990

Weight-training injuries in adolescents.

We studied the incidence of injury caused by weight training in junior and senior high school football players. Three hundred fifty-four subjects completed a retrospective injury questionnaire; histories were confirmed for high school athletes. Cumulative incidence and incidence rates were determined for injuries causing more than 7 days of missed participation. The cumulative incidences of injuries were as follows: all athletes, 7.6% (27/354); junior high school athletes, 7.1% (7/98); high school freshman/junior varsity athletes, 9.4% (15/159); and high school varsity athletes, 5.2% (5/97). The total incidence rate was 0.082 injuries per person-year, with 0.11 injuries per person-year in junior high school athletes, 0.091 injuries per person-year in high school freshman/junior varsity players, and 0.051 injuries per person-year in high school varsity players. Differences in the incidence measures among groups were not statistically significant. The most common injury type was a strain (74.1%), and the most common site was the back (59.3%). Certain exercise apparently caused more back injuries in older athletes.

Adolescent↗
PubMed1990

Fluprazine hydrochloride: no influence on the odor detection performance of male rats.

Fluprazine hydrochloride (DU 27716) decreases copulatory and offensive attack behaviors of male rats and increases their latency to locate buried food in an open field. Since such behaviors are mediated to some degree by the olfactory system, several investigators have hypothesized that this drug may produce an overall impairment in olfactory sensitivity. To test this hypothesis, the influences of five doses of fluprazine hydrochloride (1.0, 2.5, 5.0, 7.5 and 10.0 mg/kg IP) on the odor detection performance of 12 adult male Long Evans rats was assessed, relative to saline, using high precision olfactometry and a go/no-go operant odor detection task. Treatments were administered every 3rd day in counterbalanced order, with the drug or saline injections occurring 30 minutes before the 260-trial test sessions. No significant influence of fluprazine was observed on odor detection performance, as measured by the nonparametric signal detection sensitivity index SI and the percentage of correct trials. These results indicate that fluprazine does not induce generalized olfactory impairment.

Animals↗