Screening methods for drugs and heavy metals in Chinese patent medicines.
Explore the source record for details and available documents.
Chemistry, Pharmaceutical↗
Biomedical subjects
G Perez
Publications and source records attributed to G Perez.
Decomposition of nitrous oxide on pillared clays.
Alumina-pillared smectites have been found to abate nitrous oxide in the presence of methane. The results indicate that the yield of the reaction (N20 --> N2 + (1/2)O2) increases when pillared clays are exchanged with transition metals, single-pass conversion rates of >70% being attainable. In particular, when double exchanged (calcium and subsequently copper) alumina pillared montmorillonite/beidellite is used as a catalyst, de-N2O activity reaches a maximum, which is maintained even after 4 h of work at a space velocity of 5.5 h(-1). A mechanism for the reaction is suggested, which implies that N2O is first adsorbed by the catalyst and then decomposes through two different paths: catalyst oxidation and catalyst reduction. Such a redox process explains the kinetic data.
Environmental Pollution↗
A randomized study of the safety and antiretroviral activity of hydroxyurea combined with didanosine in persons infected with human immunodeficiency virus type 1. American Foundation for AIDS Research Community-Based Clinical Trials Network.
This randomized open-label trial of human immunodeficiency virus type 1-infected persons compared safety and efficacy for 38 patients receiving hydroxyurea/didanosine combination therapy with findings in 42 persons given didanosine monotherapy for 12 weeks, followed by 12 weeks of hydroxyurea/didanosine combination therapy for all patients. Week 12 on-treatment group comparisons showed a mean decrease in virus load between hydroxyurea/didanosine versus didanosine groups of -0.93 versus -0.74 log10 copies/mL (P=.20); a higher percentage of the hydroxyurea/didanosine group below the assay's detection limit (500 copies/mL), 29% versus 7% (P=.017); and median change in CD4 cells for the hydroxyurea/didanosine versus didanosine group of 0 versus 43 cells/mm3 (P=.045), although median change in CD4 percentage was similar (0.9% vs. 1.2%, P=.64). Week 24 virus load reductions and CD4 cell changes were similar in both groups. Intent-to-treat and on-treatment analyses showed similar results. The hydroxyurea/didanosine combination was well tolerated.
Adult↗
Status of selected nutrients and progression of human immunodeficiency virus type 1 infection.
BACKGROUND: Immune function is highly dependent on nutritional status because the large mass and high rate of cellular turnover of the immune system make it a major user of nutrients. Furthermore, nutrient requirements may be increased during acute and chronic infections, including HIV-1 infection. OBJECTIVE: The current study was designed to assess relations among HIV-1 progression and 11 nutritional and demographic variables. DESIGN: The participants were 106 HIV-infected outpatients and 29 uninfected control subjects (n = 89 men and 46 women; age range: 35-57 y). The HIV-infected subjects represented a broad range of disease progression. RESULTS: We found lower concentrations of plasma and erythrocyte magnesium and of erythrocyte reduced glutathione beginning early in the course of HIV-1 infection. Significantly decreased hematocrit and increased serum copper concentration developed only late in the course of the disease. Statistically significant univariate associations were found between the CD4(+) T lymphocyte count and hematocrit, plasma magnesium concentration, and plasma zinc concentration. The lowest erythrocyte magnesium concentrations occurred in HIV-infected subjects who consumed alcoholic beverages. Independent variables that were significant joint predictors of CD4(+) cell count in multiple regression analyses were hematocrit and plasma free choline and zinc concentrations. These 3 factors together explained 43% of the variability in CD4(+) cell counts. CONCLUSION: The results provide evidence that compromised nutritional and antioxidant status begin early in the course of HIV-1 infection and may contribute to disease progression.
Adult↗
HIV therapeutics: past, present, and future.
Explore the source record for details and available documents.
Anti-HIV Agents↗
Effect of hemodialysis on the signal-averaged electrocardiogram.
The presence of late potentials (LPs) on signal-averaged electrocardiography (SAECG) is predictive of ventricular tachycardia. The effect of hemodialysis (HD) on SAECG has not been well studied. SAECG was evaluated in 28 patients with chronic renal failure immediately before and after HD. In each SAECG, QRS duration, low-amplitude signal duration (LASd), and root-mean-square voltage of the terminal 40 milliseconds of the QRS (RMS40) were measured. To evaluate the effect of fluid removal on SAECG, the last 12 patients were studied during two different HD sessions, one with and one without fluid removal. Two-dimensional echocardiography was performed before and after HD on these 12 patients. At baseline, four patients met the criteria for LPs on SAECG. Only one patient met the criteria for LPs on SAECG after HD. After HD, the mean LASd decreased (28.3 +/- 12.9 to 24.9 +/- 10.1 milliseconds; P = 0.041) and RMS40 increased (63.0 +/- 56.9 to 79.0 +/- 59.2 microV; P = 0. 006). Among the 12 patients who underwent HD with and without fluid removal, left ventricular end-diastolic dimension decreased with (5. 4 +/- 0.6 to 5.1 +/- 0.6 cm; P = 0.024) but not without fluid removal (5.2 +/- 0.3 to 5.1 +/- 0.4 cm; P = not significant [NS]). RMS40 improved with (43.8 +/- 23.1 to 53.2 +/- 22.6 microV; P = 0. 03) but not without fluid removal (51.0 +/- 26.5 to 51.5 +/- 24.2 microV; P = NS). A significant negative correlation was found between change in body weight and change in RMS40 parameter (r = 0. 456; P = 0.0381). SAECG parameters are abnormal in a significant proportion of patients with chronic renal failure and improve with HD despite electrolyte and other proarrhythmic changes. Decreased left ventricular dimension because of fluid removal during HD is one possible explanation for this improvement.
Electrocardiography↗
Streptococcus pneumoniae antibiotic resistance in Northern Territory children in day care.
BACKGROUND: There is evidence that the rapid rise in Streptococcus pneumoniae (SP) antimicrobial resistance seen in other countries may have commenced in Australia. Streptococcus pneumoniae carriage and resistance levels are described for urban Northern Territory children in day care. METHODS: A prospective cohort study was conducted of 250 children in nine Darwin day care centres between 24 March and 15 September 1997. Each fortnight nasopharyngeal swabs were collected from children, and parents were interviewed about medications administered. RESULTS: Streptococcus pneumoniae was detected in 52% (1028/1974) of all nasopharyngeal swabs. Streptococcus pneumoniae was isolated from 92% (231/250) of children at some time. Penicillin resistance was found in 30% (312/1028) of isolates using a screening test. Of these, 256 (82%) had resistance confirmed by E-test. Two hundred and one (20% of all isolates) had intermediate penicillin resistance and 55 (5% of all isolates) had high level resistance. Ceftriaxone resistance was found in 19% of children's first isolates. Resistance to other antibiotics was also common: co-trimoxazole 45%, erythromycin 17%, tetracycline 17% and chloramphenicol 13%. A total of 17% (172/1028) of the isolates were multiresistant. The average fortnightly proportion of children given antibiotics was 16% (405/2476). CONCLUSION: Levels of intermediate and high level penicillin resistance in this day care population are consistent with previous data from the Northern Territory, and considerably higher than the rest of Australia. The national trend of increasing pencillin resistance is likely to continue.
Australia↗
A new statistical method for transfer coefficient calculations in the framework of the general multiple-compartment model of transport for radionuclides in biological systems.
A new and simple statistical procedure (STATFLUX) for the calculation of transfer coefficients of radionuclide transport to animals and plants is proposed. The method is based on the general multiple-compartment model, which uses a system of linear equations involving geometrical volume considerations. By using experimentally available curves of radionuclide concentrations versus time, for each animal compartment (organs), flow parameters were estimated by employing a least-squares procedure, whose consistency is tested. Some numerical results are presented in order to compare the STATFLUX transfer coefficients with those from other works and experimental data.
Animals↗
Structural models of antibody variable fragments: a method for investigating binding mechanisms.
The value of comparative molecular modeling for elucidating structure-function relationships was demonstrated by analyzing six anti-nucleosome autoantibody variable fragments. Structural models were built using the automated procedure developed in the COMPOSER software, subsequently minimized with the AMBER force field, and validated according to several standard geometric and chemical criteria. Canonical class assignment from Chothia and Lesk's [Chottin and Lesk, J. Mol. Biol., 196 (1987) 901; Chothia et al., Nature, 342 (1989) 877] work was used as a supplementary validation tool for five of the six hypervariable loops. The analysis, based on the hypothesis that antigen binding could occur through electrostatic interactions, reveals a diversity of possible binding mechanisms of anti-nucleosome or anti-histone antibodies to their cognate antigen. These results lead us to postulate that antinucleosome autoantibodies could have different origins. Since both anti-DNA and anti-nucleosome autoantibodies are produced during the course of systemic lupus erythematosus, a non-organ specific autoimmune disease, a comparative structural and electrostatic analysis of the two populations of autoantibodies may constitute a way to elucidate their origin and the role of the antigen in tolerance breakdown. The present study illustrates some interests, advantages and limits of a methodology based on the use of comparative modeling and analysis of molecular surface properties.
Amino Acid Sequence↗
Behavioral and demographic risk factors for transmission of human immunodeficiency virus type 1 in heterosexual couples: report from the Heterosexual HIV Transmission Study.
We compared 224 heterosexual couples who were discordant for human immunodeficiency virus (HIV) type 1 infection (one partner HIV infected) with 78 HIV-concordant couples (both partners HIV infected) to identify demographic and behavioral risk factors for HIV transmission. Among the 229 couples whose male partner was first infected, HIV-concordant couples had engaged in anal sex more frequently before and after knowing that the male was infected than had HIV-discordant couples. Pap smears of grade 2 or higher (inflammation) were more prevalent among the second-infected female partners in HIV-concordant couples than among uninfected women in discordant couples (58% vs. 23%; P < .001). Anal sex and unprotected vaginal sex after knowledge of a male partner's infection were significant correlates of concordance in a multivariate logistic model, as were ethnicity, marital status, and antiviral therapy. Ethnicity strongly predicted concordance, even after controlling for sexual risk behaviors and stage of disease.
Adult↗
Rates of tuberculosis infection in healthcare workers providing services to HIV-infected populations. Terry Beirn Community Programs for Clinical Research on AIDS.
OBJECTIVE: To assess the prevalence of tuberculosis (TB) or a positive skin test in healthcare workers (HCWs) providing services to human immunodeficiency virus (HIV)-infected individuals and to determine prospectively the incidence of new infections in this population. DESIGN: This prospective cohort study enrolled 1,014 HCWs working with HIV-infected populations from 10 metropolitan areas. Purified protein derivative (PPD) tuberculin skin tests were placed at baseline and every 6 months afterwards on those without a history of TB or a positive PPD. Demographic, occupational, and TB exposure data also were collected. SETTING: Outpatient clinics, hospitals, private practice offices, and drug treatment programs providing HIV-related healthcare and research programs. PARTICIPANTS: A voluntary sample of staff and volunteers from 16 Community Programs for Clinical Research on AIDS units. RESULTS: Factors related to prior TB or a positive skin test at baseline included being foreign-born, increased length of time in health care, living in New York City, or previous bacille Calmette-Guerin vaccination. The rate of PPD conversion was 1.8 per 100 person years of follow-up. No independent relation was found between the amount or type of contact with HIV-infected populations and the risk of TB infection. CONCLUSION: These data provide some reassurance that caring for HIV-infected patients is not related to an increased rate of TB infection among HCWs in these settings.
AIDS-Related Opportunistic Infections↗
A comparative trial of zidovudine administered every four versus every twelve hours for the treatment of advanced HIV disease.
Zidovudine is approved for administration in doses given every 4 hours. Less frequent dosing has been used in many clinical trials, but the toxicity and efficacy of such regimens have not been formally compared with the approved regimen. In this multicenter, randomized, double-blind, controlled trial, the safety, tolerance and efficacy of 600 mg of zidovudine given daily in two or six divided doses were compared. Three hundred and twenty patients with a CD4 lymphocyte count < 250 cells/mm3 (mean, 104 cells/mm3) or a prior AIDS-defining illness were treated with zidovudine 100 mg every 4 hours (regimen A) or 300 mg every 12 hours (regimen B). Eighty-eight patients (56%) and 94 patients (58%), assigned to regimens A and B, respectively, completed the planned 48 weeks of treatment. Serious anemia (hemoglobin < or = 7.5 g/dl) occurred in 13% and 7% of patients treated with regimens A and B, respectively (difference, 6%, 95% confidence interval [CI], 2, 12%; p = .13). The mean duration of treatment and the frequency of neutropenia and symptomatic complaints including nausea and headache were similar in the two treatment groups. The number of patients experiencing a new opportunistic infection (18% versus 20% for regimens A and B, respectively), and the number of deaths (five in each group) did not differ significantly between groups. The effect of treatment on CD4 lymphocyte counts and HIV p24 antigenemia also was similar for both regimens. Zidovudine given at the more convenient dose of 300 mg twice daily has similar safety, and tolerance and appears to have similar efficacy to the currently approved regimen. Use of this regimen should help simplify the treatment of HIV disease.
Adult↗
A controlled trial of isoniazid in persons with anergy and human immunodeficiency virus infection who are at high risk for tuberculosis. Terry Beirn Community Programs for Clinical Research on AIDS.
BACKGROUND: Patients with human immunodeficiency virus (HIV) infection and latent tuberculosis are at substantial risk for the development of active tuberculosis. As a public health measure, prophylactic treatment with isoniazid has been suggested for HIV-infected persons who have anergy and are in groups with a high prevalence of tuberculosis. METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled trial of six months of prophylactic isoniazid treatment in HIV-infected patients with anergy who have risk factors for tuberculosis infection. The primary end point was culture-confirmed tuberculosis. RESULTS: The study was conducted from November 1991 through June 1996. Over 90 percent of the patients had two or more risk factors for tuberculosis infection, and nearly 75 percent of patients were from greater New York City. After a mean follow-up of 33 months, tuberculosis was diagnosed in only 6 of 257 patients in the placebo group and 3 of 260 patients in the isoniazid group (risk ratio, 0.48; 95 percent confidence interval, 0.12 to 1.91; P=0.30). There were no significant differences between the two groups with regard to death, death or the progression of HIV disease, or adverse events. CONCLUSIONS: Even in HIV-infected patients with anergy and multiple risk factors for latent tuberculosis infection, the rate of development of active tuberculosis is low. This finding does not support the use of isoniazid prophylaxis in high-risk patients with HIV infection and anergy unless they have been exposed to active tuberculosis.
AIDS-Related Opportunistic Infections↗
Effects of hemodialysis on left ventricular diastolic filling.
Diastolic Doppler filling parameters were measured before and after hemodialyses, performed once with and once without fluid removal. Changes occurred only with fluid removal and correlated with weight loss, indicating that they are the result of reduction in preload.
Aged↗
Lymphocyte shedding from genital tract of human immunodeficiency virus-infected women: immunophenotypic and clinical correlates.
OBJECTIVE: Our purpose was to describe the lymphocyte subpopulations in genital tract samples from human immunodeficiency virus-infected women and the clinical correlates associated with lymphocyte shedding. STUDY DESIGN: Genital tract samples of women infected with human immunodeficiency virus-1 were processed for immunophenotyping analysis with a FACScan flow cytometer. Immunologic and virologic characteristics of women with and without lymphocyte shedding were compared with t test, Wilcoxon rank test, or Fisher's exact test. RESULTS: The rate of genital lymphocyte shedding among human immunodeficiency virus-1-infected women was 39%. Genital shedding was not related to age, race, use of antiretroviral therapy, or positive human immunodeficiency virus-1 culture. A negative rank correlation (r = -0.71, p = 0.047) between CD3+ CD4+ counts in peripheral blood and genital tract was observed. The majority of the lymphocyte cells were CD3+ CD8+, and > 80% of the CD3+ CD4+ cells were memory cells. CONCLUSION: The immune profile of the genital tract lymphocytes is suggestive of a local mucosal immune response.
Adult↗
Modeling of anti-nucleosome immunoglobulin Fv domains: analysis of electrostatic interactions.
Three-dimensional structural models of six murine anti-(H2A-H2B) monoclonal autoantibody variable fragments were built by comparative molecular modeling using the COMPOSER software. Analysis of the antibody combining sites is based on the hypothesis that ionic and/or electrostatic interactions predominate in antigen antibody binding, as suggested by the cationic nature of histones and the amino acid sequences of the antibody hypervariable regions. The study of the electrostatic potentials of their combining site surfaces, computed with the MOLCAD software, and the comparison with the electrostatic potentials of 13 selected control mAbs show the lack of a unique electrostatic pattern. One group of three mAbs expresses a strong and large electronegative area, supporting the hypothesis that ionic interactions predominate in antigen recognition. The second group, containing the other three mAbs, exhibits an alternation of electropositive and electronegative areas. All, however, present a localized electronegative area in the vicinity of H-CDR1 and H-CDR2 loops that is generated by the presence of at least one acidic residue. The model suggesting that the binding activity may depend on charged residues at the same site is reminiscent of what was previously reported in anti-DNA mAbs. In addition, the alternation of electropositive areas and electronegative areas in second group mAbs is also frequently observed in certain anti-DNA mAbs. These data argue for the existence of relationships between these two autoantibody populations and suggest that they share a common immunogenic particle formed by anionic and cationic components, such as a nucleosome.
Amino Acid Sequence↗
Dichotomizing stroke outcomes based on self-reported dependency.
Patients participating in a clinical trial of stroke therapy were assessed 3 months after randomization using the Barthel Index, the Modified Rankin Scale, questions on activities of daily living, and extent of recovery. Those who needed help in performing the activities of daily living and had not recovered completely were classified as dependent. Self-reported dependency had a sensitivity of 94% and specificity of 80% against the Barthel Index dichotomized at 16 or below, or a sensitivity of 85% and specificity of 87% against the Modified Rankin Scale dichotomized at 2 or above.
Activities of Daily Living↗
Lymphocyte immunoregulatory cells present in semen from human immunodeficiency virus (HIV)-infected individuals: a report from the HIV Heterosexual Transmission Study.
The purpose of this study was to determine the types and distribution of immune subsets present in semen from human immunodeficiency virus (HIV)-infected (HIV+) individuals and to compare these values with those measures in semen from HIV-negative (HIV-) individuals. To accomplish this, a direct three-color monoclonal antibody labeling technique was employed to identify immune cells in fresh ejaculates. Once labeled, the percent of each immune subset present in the ejaculate was determined by flow cytometric analysis. The percent of CD3+ cells present in the semen of the HIV+ group showed no significant difference when compared with semen from the HIV- group. Analysis of the CD4+ subset yielded a significantly lower percent in the HIV+ group than in the HIV- group. The analysis of the CD8+ subset yielded a higher percent of cells present in semen from HIV+ individuals. The CD8 higher value along with lower CD4 value results in a lower CD4/CD8 ratio in the HIV+ group. Further subset studies showed that the percent of cells expressing naive (CD4+ CD45RA+) and memory (CD4+ CD45RO+) markers was lower in the HIV+ group. This study provides additional data supporting the utility of flow cytometry and monoclonal antibodies to immunophenotypic cells present in semen ejaculates. It is also the first reported application of the technique to a disease-based model and may be useful to better understand issues of mucosal immunity and transmission of sexually transmitted diseases such as HIV.
Acquired Immunodeficiency Syndrome↗