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Biomedical subjects

L Peralta

Publications and source records attributed to L Peralta.

At least 19 recordsLinked to original sources
PubMed2001

Evaluation of youth preferences for rapid and innovative human immunodeficiency virus antibody tests.

OBJECTIVE: To determine youth preferences for Food and Drug Administration (FDA)-approved and investigational human immunodeficiency virus (HIV) antibody collection and testing methods before and after subjects learned of test result response times; to determine how influential test result response times are on participants' preferences. DESIGN: After health educators explained and demonstrated 6 different HIV antibody collection and testing strategies (3 saliva, 1 urine, and 2 fingerstick methods), participants completed a confidential survey about test method preference and tried the different testing methods. The participants had an opportunity to re-rank their test method preference after learning about each test's result response time. SETTING: Health education sessions in both clinical and community settings. PARTICIPANTS: Youths aged 12 to 24 years. RESULTS: An oral collection device with a rapid saliva test was the most highly preferred test method. The preference for this method and the rapid response test methods via fingerstick procedures improved significantly after subjects learned of the rapid result response time, while the other methods were given significantly lower preference rankings after subjects learned of the longer result response times. Shifts in preference rankings were not related to sex, age, ethnic group, experience with HIV testing, or practice of risk behaviors. CONCLUSIONS: Our research supports the use of noninvasive and rapid HIV testing methods with rapid response times for adolescents to assist in the early identification of HIV status, while offering HIV prevention opportunities and immediate linkage to care.

Adolescent↗
PubMed2001

Serologic response to hepatitis B vaccine in HIV infected and high-risk HIV uninfected adolescents in the REACH cohort. Reaching for Excellence in Adolescent Care and Health.

PURPOSE: To evaluate hepatitis B (HBV) vaccine response rates in HIV infected and high-risk HIV uninfected youth and examine associations with responsiveness in the HIV infected group. METHODS: Cohorts within the Reaching for Excellence in Adolescent Care and Health (REACH) study population were defined based on receipt of HBV vaccine both retrospectively and prospectively. Sero-responsiveness was determined by HBsAb measurements. Testing was done for HBsAg, HBsAb, and HBcAb. For HBsAb, a value of > 10 International Units per liter was considered a positive response, and the data were collected as either positive or negative from each of the reporting laboratories. Covariates of responsiveness were explored in univariate and multivariate models for each cohort. RESULTS: Sixty-one subjects had received a three-dose vaccination course at the time of entry into REACH. HIV uninfected subjects had significantly higher rates of response by serology compared with HIV infected subjects (70% vs. 41.1%; chi(2) = .05; RR = .586, 95% CI: .36-.96). By the time of an annual visit 43 subjects had received three vaccinations with at least one occurring in the study period. The rates of response were similar for the HIV infected and uninfected groups (37.1% vs. 37.5%) in this cohort. Univariate and multivariate analysis in the prospective HIV infected group (N = 35) found an association between elevated CD8(+)/CD38(+)/HLA-DR(+) T cells and lack of HBV vaccine responsiveness (6.7% vs. 60%; chi(2) = .03; RR = .12, 95% CI: .02- .55). CONCLUSIONS: The poor HBV vaccine response rate in the HIV uninfected high-risk adolescents was unexpected and suggests that HBV vaccination doses have not been optimized for older adolescents. This is the first report of decreased responsiveness in HIV infected subjects being associated with elevated CD8(+)/CD38(+)/HLA(-)DR(+) T cells and suggests that ongoing viral replication and concomitant immune system activation decreases the ability of the immune system in HIV infected subjects to respond to vaccination.

ADP-ribosyl Cyclase↗
PubMed2001

Incident pregnancy rates in HIV infected and HIV uninfected at-risk adolescents.

PURPOSE: To compare pregnancy incidence between HIV infected and HIV uninfected adolescents over a 3-year period and to characterize factors that differentiate pregnant from nonpregnant HIV infected females. METHODS: Female adolescents enrolled in Reaching for Excellence in Adolescent Care and Health (REACH), a national cohort study, and nonpregnant at baseline comprised the sample (n = 345). Subject information on pregnancy, risk behavior, and psychosocial characteristics was obtained through interview, chart review, physical examination and laboratory data collected every 3 months. Incident pregnancy rate was analyzed using Cox proportional hazards modeling; the predictors of incident pregnancy were evaluated using repeated measures analysis. RESULTS: Ninety-four pregnancies were identified over 3 years. No significant difference in pregnancy incidence was detected between HIV infected and uninfected females (20.6 and 28.4 per 100 person-years, respectively, p = .16). However, for adolescents with living children at entry, HIV infected females were significantly less likely to become pregnant than HIV uninfected (HR = .45; p = .03). Among HIV infected adolescents, significant predictors of incident pregnancy were older age (p = .01) and not using hormonal contraception (p = .00), whereas increased spiritual hope and passive problem-solving capacity were protective against pregnancy (p = .02, and.05, respectively). Multivariate analysis revealed pregnancy prior to study entry to be predictive for (OR = 3.0; 95% CI: 1.2-7.7), and increased spiritual hope to be protective (OR = .4; 95% CI: .2-.9) against incident pregnancy in HIV infected females without the hormonal contraceptive variable in the model. CONCLUSIONS: The pregnancy rate is high in this study population. Further research is needed into its determinants and attenuating factors, particularly the role of spiritual elements, to design better contraceptive services and reproduction-related education targeting high-risk youth.

Adolescent↗
PubMed2001

Contraceptive choices in HIV infected and HIV at-risk adolescent females.

PURPOSE: To describe reported contraception use in HIV infected and HIV uninfected but at-risk female adolescents, and determine associations with the reported consistent use of effective contraception methods, including its association with pregnancy. METHODS: HIV infected and at-risk female youth, aged 13-18 years, who were sexually active and reporting no intention to become pregnant, were included. Contraception use data from three consecutive visits (approximately 6 months apart) were used. RESULTS: Ninety-four percent of HIV infected and 89% of at-risk subjects reported choosing a main contraception method with demonstrated efficacy when used consistently. Approximately 50% chose partner condoms. HIV infected youth were more likely to report 100% partner condom use in the past 3 months (73% vs. 46%; OR 3.3; 95% CI: 1.7-5.6). At-risk youth were 2.5 times more likely than HIV infected subjects to report using nothing (95% CI: 1.1-5.8). Slightly more than half (56%) demonstrated the consistent reporting of effective methods (CREM) of contraception. In multivariate analysis, HIV infection (OR 4.0; 95% CI: 2.2-8.2) and African-American race (OR 2.7; 95% CI: 1.1-6.6) were significantly associated with CREM. Subjects reporting inconsistent or unreliable contraception use had higher 1-year pregnancy rates than CREM subjects (32% vs. 14%; p = .002). CONCLUSIONS: Only half of HIV infected and at-risk youth reported using effective contraception consistently, despite its availability. Additionally, regardless of reported contraceptive use, the rates of unplanned pregnancy were unacceptably high.

Adolescent↗
PubMed2001

Correlation between urine and cervical specimens for the detection of cervical Chlamydia trachomatis and Neisseria gonorrhoeae using ligase chain reaction in a cohort of HIV infected and uninfected adolescents.

PURPOSE: (a) To examine the concordance between ligase chain reaction (LCR) results from urine and cervical samples for Chlamydia trachomatis and Neisseria gonorrhoeae in HIV infected and uninfected adolescent women, and (b) to examine factors that may influence the concordance of LCR results in this population. METHODS: Baseline specimens from 269 of 334 female subjects enrolled in a longitudinal study of HIV infection in adolescents were analyzed for C. trachomatis and N. gonorrhoeae using ligase chain reaction (LCR) assays in a central laboratory. Concordance was measured using kappa coefficient with permutation analyses to calculate the difference between HIV status groups. Discordant LCR results were examined for the co-infection with the other microorganism, bacterial vaginosis, or Trichomonas vaginalis. RESULTS: The prevalence of C. trachomatis detected by LCR in the HIV infected and uninfected groups was 19.3% and 12.2%, respectively (p = .16); the prevalence of N. gonorrhoeae was 7.0% and 2.4%, respectively (p = .16). Urine LCR assay sensitivity to detect cervical C. trachomatis infection was 86% (95% CI: 68%-96%) in the HIV infected group and 100% (95% CI: 69%-100%) in the HIV uninfected group. Urine LCR assay sensitivity to detect cervical N. gonorrhoeae infection was 92% (95% CI: 62%-100%) in the HIV infected group. There were only 2 N. gonorrhoeae infections in the HIV uninfected group, and both were urine LCR positive. Differences in sensitivity between HIV infected and HIV uninfected subjects were not statistically significant. Coinfection with N. gonorrhoeae, bacterial vaginosis or Trichomonas vaginalis was not associated with the concordance of urine and cervical LCR results. CONCLUSION: The relatively high sensitivity of urine LCR testing overall suggests that urine screening may be reasonable for sexually active adolescent females with or without HIV infection in situations in which urine screening may be more acceptable than pelvic examinations.

Adolescent↗
PubMed2001

Performance of antigens used in detecting delayed-type hypersensitivity in adolescents infected with the human immunodeficiency virus.

We examined the performance of delayed-type hypersensitivity (DTH) antigens employing a new Candida albicans product in a human immunodeficiency virus (HIV)-infected and nonanergic adolescent population. Diameters of induration (in millimeters) for three intradermally applied antigens (C. albicans, tetanus toxoid, and mumps) were compared in a population of HIV-infected 12 to 18 year olds at study entry in a national multicenter study of HIV disease progression. CD4+ T-cell counts were measured in quality-controlled laboratories. The influence of past immunization, gender, and clinical status on antigen reactivity was evaluated with contingency table comparisons and relative risk estimation. Nearly one-half of the 123 eligible subjects were untreated, and almost three-quarters were early in HIV disease by clinical indicators. There was no statistically significant difference in reactivity by past immunization status. Candida antigen (CASTA; Greer Laboratories) evoked DTH response in a significantly higher number of males and females at every level of induration (largest P value, 0.049 for male comparisons; all P values, <0.001 for females) and in subjects with early and intermediate HIV disease at every level of induration (all P values, <0.0001) than either tetanus or mumps antigens. No two-antigen combination was as useful as all three antigens across either gender or clinical categories, although candida and tetanus was the most useful two-antigen combination at indurations of <3 mm. The superior performance of a new C. albicans antigen may extend the utility of DTH assessment in monitoring immune function.

Adolescent↗
PubMed2000

The prevalence of anergy in human immunodeficiency virus-infected adolescents and the association of delayed-type hypersensitivity with subject characteristics.

PURPOSE: To examine the prevalence of anergy in HIV-infected adolescents and factors associated with its occurrence. METHODS: Anergy was defined as less than 2mm induration to each of three intradermally applied antigens (Candida albicans, tetanus toxoid, and mumps) between 24 and 96 hours in a population of HIV-infected adolescents aged 12-18 at entry in a national multicenter study of HIV disease progression. CD4(+) T-cell counts and plasma HIV-1 RNA were measured in quality controlled laboratories. Factors associated with the probability of anergy were examined with contingency table comparisons, tree-structured classification, and logistic regression analyses. RESULTS: Overall prevalence of anergy in this clinic-based population of 167 was 11% [7% in males and 12% in females (p = 0.57)]. The sole significant predictor of anergy was decreased CD4(+) T-cell count (p = 0.005). CONCLUSION: The prevalence of anergy is low in this HIV-infected population compared to older infected cohorts. The occurrence of differential rates of anergy in particular age and sex groupings that may be related to intrinsic immunologic differences requires further study.

Adolescent↗
PubMed2000

Functional aerobic impairment in adolescents seropositive for HIV: a quasiexperimental analysis.

OBJECTIVE: To determine the degree to which cardiorespiratory insufficiency limits physical performance in adolescents seropositive for human immunodeficiency virus (HIV). DESIGN: Quasiexperimental, case series design. SETTING: Rehabilitation physiology laboratory. PARTICIPANTS: Seventeen adolescents (12 women, 5 men; age, 18 +/- 2 yr; weight, 74.7 +/- 19.3 kg; height, 170 +/- 9 cm) with HIV infection (viral load, 22,043 +/- 55,869 copies/mL; CD4 count, 499 +/- 210/mL) who were free of comorbid conditions limiting treadmill performance. MAIN OUTCOME MEASURES: Spirometric measurements of oxygen uptake and anaerobic threshold obtained from a peak exercise treadmill test using the modified Bruce protocol. RESULTS: Measured peak oxygen consumption (VO2) was 42% +/- 19% lower than expected (p < .025), suggesting a significant functional aerobic impairment (FAI) or peak VO2 less than 73% of expected values. Peak VO2 was only slightly higher (p < .05) than the oxygen uptake requirements for the most intense activities of daily living (ADL). Anaerobic threshold was only slightly higher (p < .05) than minimum ADL intensities. CONCLUSIONS: Cardiorespiratory insufficiency and FAI limited the ability to perform even low levels of physical activity in these adolescents with mild HIV seropositivity. Disability identified by quantification of FAI may affect implementation of the American with Disabilities Act and public health policy.

Adolescent↗
PubMed2000

Concordance of human papillomavirus in the cervix and urine among inner city adolescents.

OBJECTIVES: To evaluate concordance for human papillomaviruses (HPVs) between cervix and urine in sexually active adolescents. METHODS: Cervical swabs and urine were collected from 80 adolescents in Baltimore, MD. Specimens were tested for 34 HPVs by PCR and for cancer-associated HPVs by Hybrid Capture (HC II) Probe B. Cervical vs. urine prevalence was evaluated by logistic regression with general estimating equations. Risk factors for prevalence and viral burden were evaluated by Fisher's exact and Kruskal-Wallis tests, respectively. RESULTS: HPV prevalence by PCR, for any HPV, was very high in the cervix (90.0%) and somewhat lower in urine (75.0%) (odds ratio, 1.07; 95% confidence interval 1.07 to 1.34). Only one adolescent was HPV-positive in urine alone. Among HPV-PCR positives at either or both sites, concordance was 82% for presence of any HPV and 40% for specific HPV types. Multiple infections were common at both sites. On an average, HC II viral burden (relative light unit ratio) was 9-fold higher in cervix than in urine (median, 47.3 vs. 4.9; P = 0.005) but correlated poorly between the two sites of the same individual (r = 0.14). Compared with normal adolescents, those with squamous intraepithelial lesions had a much higher prevalence of HPV by HC II in cervix (100% vs. 28.6, P<0.0001) as well as in urine (86.7% vs. 35.4%, P = 0.002) and a significantly higher viral burden in the cervix (median, 141.8 vs. 7.3, P = 0.0045) but not in urine (median, 22.7 vs. 4.38; P = 0.13). CONCLUSION: There was a very high prevalence of HPV in cervix and urine of sexually active adolescents. Testing urine for HPV may be useful in epidemiologic investigations and in monitoring of infected women.

Adolescent↗
PubMed2000

Histologic development of cervical ectopy: relationship to reproductive hormones.

BACKGROUND AND OBJECTIVES: Cervical ectopy has been proposed as a risk factor for chlamydial infection, HIV, and other sexually transmitted diseases (STDs). Ectopy is a histologic phenomenon resulting from a complex interplay of morphologic and hormonal processes. Reproductive hormones influence the production of ectopy during late fetal life, puberty, pregnancy, and with use of oral contraceptives. Ectopy is modified over time by squamous metaplasia and epitheliazation, low pH, trauma, and possibly by cervical infection. STUDY DESIGN: The authors review the histologic development of ectopy from late fetal life to menopause to understand STD risk. RESULTS: Ectopy is often assessed and quantified by direct, unaided observation during speculum examinations. This method may result in inaccurate estimates and misclassification with the transformation zone. CONCLUSION: Valid, reproducible measures of ectopy are necessary for epidemiologic studies to examine the impact of exogenous hormonal contraceptives on the development of ectopy and on potential infection risk.

Adolescent↗
PubMed2000

Relationship of hormonal contraception and cervical ectopy as measured by computerized planimetry to chlamydial infection in adolescents.

BACKGROUND: Adolescents are at increased risk for chlamydial infection and its sequelae. Hormonal contraception and cervical ectopy were previously suggested risk factors for chlamydia. GOAL: To determine if chlamydia is more prevalent in female participants with greater ectopy and in hormonal contraceptive users. STUDY DESIGN: Ninety-seven adolescent females aged 11 to 20 years were recruited from two Baltimore inner-city clinics. After administering a reproductive history questionnaire, endocervical specimens were tested for Chlamydia trachomatis by polymerase chain reaction. After acetic acid application to the cervix, cervical photographs were taken, the area of ectopy was quantified by computerized planimetry, and ectopy was categorized as none (0mm2), mild (< 22mm2), and moderate (> 22mm2). The likelihood of chlamydia by ectopy and type of hormonal contraceptive use was determined by logistic regression adjusted for age and sexual partners. RESULTS: The odds of chlamydial infection was similar in persons with mild ectopy compared with no ectopy (adjusted odds ratio [OR], 0.76; 95% CI, 0.14-4.03), and in persons with moderate ectopy compared with no ectopy (adjusted OR, 1.94; 95% CI, 0.40-9.39). The likelihood of chlamydia was higher in depot-medroxyprogesterone acetate users compared with nonhormone users (adjusted OR, 5.44; 95% CI, 1.25-23.6). Oral contraceptive users did not have an increased likelihood of chlamydia (adjusted OR, 0.92; 95% CI, 0.10-8.78). CONCLUSION: Using a new, reliable, and standardized technique to quantify cervical ectopy, the authors did not find an elevated prevalence of chlamydial infection in adolescents with cervical ectopy. Depot-medroxyprogesterone acetate use may increase the risk of chlamydial infection compared with combined estrogen-progestin oral contraceptives.

Adolescent↗
PubMed1999

Cervical ectopy and the transformation zone measured by computerized planimetry in adolescents.

OBJECTIVE: To determine whether cervical ectopy and the transformation (T) zone were larger in adolescents using oral contraceptives (OCs) compared to depot medroxyprogesterone acetate (DMPA). METHOD: Cervical photographs were taken on 91 adolescents in Baltimore, Maryland. Ectopy and T zone size were measured using computerized planimetry. Patients provided reproductive and sexual history. Correlates of ectopy and T zone size were identified by proportional odds and linear regression models, respectively. RESULT: Twenty-five women had no ectopy. Parity was independently associated with greater ectopy (OR 3.9, 95% CI 1.37-11.11). Predictors of smaller ectopy were douching (OR 0.23, 95% CI 0.09-0.65), and shorter sexual history (OR 0.20, 95% CI 0.05-0.74). Neither OC or DMPA were associated with ectopy. Predictors of greater T zone size were years since menarche (13.8 mm2/year, P = 0.003) and OCs (54.7 mm2, P = 0.05). DMPA predicted a smaller T zone (-67.0 mm2, P = 0.01). CONCLUSION: Computerized planimetry provides standardized measurements. Douching and sexual activity may decrease ectopy through increased squamous metaplasia. Hormonal contraceptives were not associated with ectopy in adolescents. However, long-term progestin use may decrease T zone size.

Adolescent↗
PubMed1998

Phosphorylation of endogenous and TEST-yolk buffer proteins by intact human sperm.

Protein kinase activity of intact, motile sperm was assessed by measuring the transfer of the terminal phosphate from [32P]ATP to tricholoroacetic acid (TCA)-precipitable casein. The action of TEST (TES and Tris) yolk buffer (TYB) treatment on phosphorylation of sperm and TYB proteins was studied by detecting labelled phosphoproteins by autoradiography of polyacrylamide gel electrophoresis (PAGE). Results demonstrate that intact, forward-motile sperm have cell surface protein kinase activities. Although the difference between the kinase activity of freshly ejaculated sperm incubated in TYB was not significant, the protein phosphorylation during incubation in TYB showed that: (i) specific sperm surface proteins were phosphorylated to different degrees during the course of treatment; (ii) TYB proteins were phosphorylated by sperm during incubation; (iii) solubilised [32P]-labelled surface proteins were similar in molecular weight to TYB-labelled proteins. Taking into account that specific proteins on the human sperm surface undergo phosphorylation during incubation in TYB and that the sperm enzyme also acts specifically on some TYB proteins that become attached to the surface of the sperm, working hypotheses are proposed that suggest some correlation between the preservation of semen in TYB and the phosphorylation of proteins by intact human sperm.

Adenosine Triphosphate↗
PubMed1994

Chronic paroxysmal hemicrania in a child.

Chronic paroxysmal hemicrania (CPH) is a relatively new condition first described in 1973. Since its first description, over 80 cases have been reported worldwide. Very few cases have been reported in children. We report the presentation of an 8-year-old boy to illustrate the problems in diagnosis and treatment of this rare disease in childhood.

Adult↗
PubMed1993

Diagnoses and symptom patterns in children presenting to a pediatric headache clinic.

The diagnosis of migraine headache in children and adolescents is complex and not well understood. This study was conducted to compare diagnostic rates, using various criteria for pediatric migraine, and specific symptom characteristics in a sample of children referred for care to a specialized pediatric headache clinic. A structured interview was used at the patient's initial assessment visit to elicit symptom patterns and therapies attempted for headache. Clinical diagnoses were based on consensus agreement reached by a multidisciplinary team. Statistically derived diagnostic rates based on International Headache Society (IHS), Prensky, Vahlquist and our own criteria were significantly lower than clinical diagnostic rates. IHS diagnostic rates were differentially distributed as a function of race, but no other effects were found for demographic variables on diagnostic rates. Specific symptom patterns, however, varied as a function of race, gender and age of the child. The results underscore the need for comprehensive, developmentally based models of the evolution of migraine headache as a foundation for future research and the further development of clinically sensitive diagnostic criteria for pediatric migraine.

Adolescent↗