PubMed Health⌕ Search

Biomedical subjects

M L Huang

Publications and source records attributed to M L Huang.

At least 37 records · Page 2Linked to original sources
PubMed1999

Multicenter comparison of PCR assays for detection of human herpesvirus 8 DNA in semen.

Reported prevalences of human herpesvirus 8 (HHV-8) (Kaposi's sarcoma-associated herpesvirus) in semen have ranged widely. This is possibly due to differences in assay sensitivity, geographic or population-based differences in the true presence of the virus in semen, and PCR contamination. This study assessed interlaboratory sensitivity and reproducibility in the analysis of blinded experimental panels, each consisting of 48 specimens and being composed of semen specimens from different healthy artificial-insemination donors (n = 30) and human immunodeficiency virus (HIV)-infected patients (n = 7) plus positive (n = 4) and negative (n = 7) controls. The experimental panels analyzed in each laboratory were identical except for being independently coded. Of 10 experiments done in five laboratories, 5 experiments from three laboratories had evidence of PCR contamination; all instances of contamination were in the context of nested PCR procedures. In the experiments with no false-positive results, HHV-8 DNA was detected in three (8%) of the 37 semen specimens (two from artificial-insemination donors and one from an HIV-positive patient) but in only 3 (1.6%) of the 184 PCRs in which these specimens were analyzed. This suggests that HHV-8 DNA is present in semen at concentrations that can be too low to allow its consistent detection. This study emphasizes the importance of performing blinded, multi-institution experiments to provide a coherent basis for comparing results and to motivate standardization of methods.

DNA, Viral↗
PubMed1999

Development of a high-throughput quantitative assay for detecting herpes simplex virus DNA in clinical samples.

We have developed a high-throughput, semiautomated, quantitative fluorescence-based PCR assay to detect and type herpes simplex virus (HSV) DNA in clinical samples. The detection assay, which uses primers to the type-common region of HSV glycoprotein B (gB), was linear from <10 to 10(8) copies of HSV DNA/20 microl of sample. Among duplicate samples in reproducibility runs, the assay showed less than 5% variability. We compared the fluorescence-based PCR assay with culture and gel-based liquid hybridization system with 335 genital tract specimens from HSV type 2 (HSV-2)-seropositive persons attending a research clinic and 380 consecutive cerebrospinal fluid (CSF) samples submitted to a diagnostic virology laboratory. Among the 162 culture-positive genital tract specimens, TaqMan PCR was positive for 157 (97%) specimens, whereas the quantitative-competitive PCR was positive for 144 (89%) specimens. Comparisons of the mean titer of HSV DNA detected by the two assays revealed that the mean titer detected by the gel-based system was slightly higher (median, 1 log). These differences in titers were in part related to the fivefold difference in the amount of HSV DNA used in the amplicon standards with the two assays. Among the 380 CSF samples, 42 were positive by both assays, 13 were positive only by the assay with the agarose gel, and 3 were positive only by the assay with the fluorescent probe. To define the subtype of HSV DNA detected in the screening assay, we also designed one set of primers which amplifies the gG regions of both types of HSV and probes which are specific to either HSV-1 (gG1) or HSV-2 (gG2). These probes were labeled with different fluorescent dyes (6-carboxyfluorescein for gG2 and 6-hexachlorofluorescein for gG1) to enable detection in a single PCR. In mixing experiments the probes discriminated the correct subtype in mixtures with up to a 7-log-higher concentration of the opposite subtype. The PCR typing results showed 100% concordance with the results obtained by assays with monoclonal antibodies against HSV-1 or HSV-2. Thus, while the real-time PCR is slightly less sensitive than the gel-based liquid hybridization system, the high throughput, the lack of contamination during processing, the better reproducibility, and the better ability to type the isolates rapidly make the real-time PCR a valuable tool for clinical investigation and diagnosis of HSV infection.

DNA, Viral↗
PubMed1998

Effects of demographic variables on vorozole pharmacokinetics in healthy volunteers and in breast cancer patients.

PURPOSE: Vorozole (VOR) is a selective nonsteroidal inhibitor of the cytochrome P450-dependent aromatase that catalyzes the conversion of androgens to estrogens. It is currently being developed as a therapeutic agent in the endocrine treatment of postmenopausal women with breast cancer. This work was aimed to explore the effects of demographic and other variables on VOR pharmacokinetics. METHODS: VOR plasma concentration-time data were obtained in healthy volunteers and in breast cancer patients after the oral administration of 2.5 mg of VOR as a single dose or once daily. The data obtained in 6 formal pharmacokinetics (PK) studies with frequent plasma sampling were included in the data base (84 healthy male and female volunteers and 13 breast cancer patients). Also included were data from 2 clinical efficacy trials involving 286 breast cancer patients who were treated for several months (1 sample per visit, up to 14 samples/patient). The nonlinear mixed-effect modeling (NONMEM) approach was applied. The two-compartment linear PK model with first-order absorption parameterized in terms of apparent clearance (CL), apparent central and peripheral volumes of distribution (Vc and Vp, respectively), apparent distributional flow (Q), and absorption constant (ka) was used. A population model was developed using data from formal PK studies. The final estimates of fixed and random effect parameters were obtained using both formal study data and clinical-efficacy trial data. RESULTS: The typical CL value obtained after a single dose was lower in patients (4.8 l/h) as compared with healthy volunteers (8.6 l/h) and did not depend on gender. The multiple- to single-dose ratio was 0.76. CL was constant over ages of up to 50 years and then decreased slightly (0.047 l/h per year). The typical CL value did not depend on any demographic variable related to body size (total body weight, WT; body surface area; lean body mass). Q and Vc were proportional to WT (0.17 l h(-1) kg(-1) and 0.43 l/kg, respectively). Vp was also proportional to WT and was higher in women as compared with men (0.64 and 0.40 l/kg, respectively). The same was true for the apparent steady-state volume of distribution. No effect of race or the duration of therapy (0.5-28 months) was seen. The unexplained variability in CL and the residual variability in VOR plasma concentrations were 39% and 28% (coefficient of variation), respectively. CONCLUSIONS: Healthy volunteer/patient, single/multiple dosing differences, and age were identified as the fixed effects influencing the CL of VOR. WT was the main determinant of distributional PK parameters. The peripheral and steady-state volumes of distribution were gender-dependent. In view of the relatively high degree of residual interpatient variability in CL, the slight effect of age on it is unlikely to be clinically significant.

Adult↗
PubMed1998

Human herpesvirus 8 in the prostate glands of men with Kaposi's sarcoma.

The epidemiology of human immunodeficiency virus (HIV)-associated Kaposi's sarcoma (KS) resembles that of a sexually transmitted pathogen. However, human herpesvirus 8 (HHV-8), the proposed cause of KS, is found in semen only infrequently and at low titers. To determine whether HHV-8 was present in the urogenital tract, transrectal ultrasound-guided prostate biopsies were obtained from six men with KS (five with concurrent HIV infection) and four without KS (three with concurrent HIV) and assayed for HHV-8 by PCR. Nine of the 10 men were seropositive for HHV-8. Five of nine HHV-8-seropositive men had HHV-8 DNA detected in prostate tissue by solution-based PCR. All five currently had KS or had it previously. In two subjects, prostate tissue was the only identified source of HHV-8. In situ PCR on serial sections of prostate indicated that HHV-8 infection was localized to discrete areas of the prostate. When detected, HHV-8 DNA was present in the nuclei of >90% of the glandular epithelial cells. In situ hybridization for HHV-8 mRNA revealed that between 1 and 5% of cells harboring HHV-8 DNA expressed viral transcripts associated with HHV-8 replication (T1.1 transcript), while >90% expressed gene products associated with viral latency (T0.7 transcript). Intermittent replication of HHV-8 in the prostate and subsequent shedding of virus in semen may be crucial factors for determining whether HHV-8 can be transmitted through sexual activity.

Adult↗
PubMed1997

Frequent detection of Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) DNA in saliva of human immunodeficiency virus-infected men: clinical and immunologic correlates.

The prevalence, quantity, temporal pattern, and clinical and immunologic correlates of shedding of Kaposi's sarcoma (KS)-associated herpesvirus (KSHV; or human herpesvirus [HHV]-8) DNA in saliva were studied. KSHV DNA was detected in saliva from 18 (75%) of 24 human immunodeficiency virus (HIV)-positive patients with KS and from 1 of 1 HIV-negative patient with KS, 3 (15%) of 20 HIV-positive patients without KS, and none of 24 controls. KSHV DNA levels ranged from 10(2.4) to 10(6) copies/mL and were lower than levels for Epstein-Barr virus but comparable to those for HHV-6. Detection of KSHV DNA in saliva was not associated with oral KS or decreased peripheral blood CD4 cell counts. KSHV DNA was not detected in semen. Resistance of KSHV DNA from saliva to DNase treatment was consistent with the presence of virions. These data suggest that KSHV can replicate in the oropharynx and that salivary contact could contribute to KSHV transmission.

Antibodies, Viral↗
PubMed1997

Absence of detectable human herpesvirus 8 in the semen of human immunodeficiency virus-infected men without Kaposi's sarcoma.

The prevalence of human herpesvirus 8 (HHV-8)/Kaposi's sarcoma (KS)-associated herpesvirus was investigated in the semen of 99 human immunodeficiency virus (HIV)-infected men (median CD4 cell count, 357/mm3) by use of a polymerase chain reaction (PCR) assay capable of detecting <10 copies of HHV-8 DNA. Of the subjects, 95 (96%) self-identified as men who have sex with men (MSM), and 3 had a history of clinical KS. Seminal cell specimens were negative for HHV-8 in 98 subjects. None of the 26 without KS (27.1% of 96 tested) who were seropositive for HHV-8 by IFA for latency-associated nuclear antigens had HHV-8 detected in their semen. The only subject with any evidence for seminal HHV-8 DNA was seropositive for HHV-8 and had active KS. HHV-8 was detected in 10 (10.4%) of 96 peripheral blood mononuclear cell specimens. The prevalence of HHV-8 DNA by PCR in semen of HIV-infected MSM without KS is low.

AIDS-Related Opportunistic Infections↗
PubMed1997

Lack of effect of amitriptyline on risperidone pharmacokinetics in schizophrenic patients.

The interaction between plasma concentrations of the tricyclic antidepressant amitriptyline and the metabolism of the new antipsychotic risperidone was studied in 12 patients with chronic schizophrenia. Each patient received 3 mg risperidone twice a day for 28 days. Amitriptyline was coadministered at doses of 50 mg/day on day 15 and 100 mg/day on days 16 to 21. Amitriptyline did not significantly affect the mean plasma concentrations or pharmacokinetics of risperidone in schizophrenic patients or influence the antipsychotic fraction (the total concentration of risperidone and 9-hydroxyrisperidone, its primary and biologically active metabolite). These results suggest that risperidone dose need not be adjusted when coadministered with amitriptyline at doses up to 100 mg/day in schizophrenic patients.

Adult↗
PubMed1997

Transmissible Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in saliva of men with a history of Kaposi's sarcoma.

We have evaluated the physical state and infectious nature of Kaposi's sarcoma-associated herpesvirus (KSHV) in the saliva of nine persons with past or current Kaposi's sarcoma (KS). KSHV DNA in saliva had the physical characteristics of DNA present in virions. Inoculation of 293 cells with cell-free saliva fluid resulted in the persistence of KSHV DNA in culture for at least 13 passages of the cells. The addition of tetradecanoyl phorbol acetate to KSHV-infected 293 cells led to increased viral DNA. Two virus-specific RNAs were detected by reverse transcriptase PCR in 293 cells infected with cell-free saliva fluid and in cells present in saliva from subjects with KSHV salivary shedding. These results indicate that infectious KSHV can be present in saliva of patients with KS.

Cell Line, Transformed↗
PubMed1997

Leukemia cutis as the initial manifestation of acute nonlymphocytic leukemia in a young child.

A 15-month-old boy was well except for asymptomatic, erythematous, wheal-like papuloplaques, macules, and nodules on his face and four extremities. It was misdiagnosed by a pediatrician and treated as urticaria for six months. Later, he was sent to our hospital for evaluation of prolonged fever. Acute nonlymphocytic leukemia (M5) with leukemia cutis was diagnosed by results of hematologic examination and examination of a skin biopsy specimen. After one course of chemotherapy, all of the skin lesions completely resolved and had not recurred. Five months after acute nonlymphocytic leukemia was diagnosed, bone marrow relapse and central nervous system involvement were noted.

Humans↗
PubMed1997

Outbreak and control of a rotaviral infection in a nursery.

Neonatal rotaviral infection generally causes an asymptomatic or mild illness. Once introduced into a nursery, it is very difficult to eradicate. We prospectively studied an outbreak of rotavirus infection in a normal newborn nursery from October 1994 through May 1995. Stool samples from infants more than 24 hours old were tested for rotaviral infection, either weekly, biweekly, or monthly. Rotavirus was identified in 164 (16%) of 1,037 tested neonates. Ninety-four (57%) rotavirus-positive neonates became symptomatic: 56 had diarrhea, 26 developed fever (rectal temperature > 38 degrees C), 25 experienced vomiting, 17 showed poor feeding, and 14 had an elevated core temperature. In total, 24 neonates were evaluated for suspected sepsis. RNA electropherotyping of samples from 91 neonates revealed infection by the same rotavirus strain in all cases. This strain differed from that isolated from 64 rotavirus-infected infants and toddlers in the pediatric ward during the same period. Infection control procedures (hand washing, isolation of infected neonates, and careful management of diapers) and early discharge of uninfected neonates were instituted, and the outbreak was eradicated 8 months after the onset. Our findings indicate that many rotavirus-infected term neonates become symptomatic and have signs suggestive of sepsis. Extended hospital stay may be an important factor in promoting rotaviral transmission. Thus, early discharge may be an additional effective method of controlling rotavirus outbreaks in a nursery.

Cross Infection↗
PubMed1996

Increased systemic availability of loperamide after oral administration of loperamide and loperamide oxide with cotrimoxazole.

1. The effects of concurrent administration of cotrimoxazole on the plasma concentration-time profiles of loperamide and its oxide were investigated in two separate studies in healthy male volunteers. Cotrimoxazole (960 mg, twice daily) was administered for 24 h before and 48 h after an oral dose of loperamide oxide (4 mg) or loperamide (4 mg). 2. Coadministration of cotrimoxazole with loperamide oxide did not alter the tmax, Cmax and AUC of loperamide oxide, whereas the Cmax (0.32 +/- 0.14 ng ml-1 without cotrimoxazole; 0.45 +/- 0.18 ng ml-1 with cotrimoxazole; P < 0.05) and AUC (8.13 +/- 1.91 ng ml-1 h without cotrimoxazole; 12.50 +/- 4.60 ng ml-1 h with cotrimoxazole; P < 0.005) of loperamide were significantly increased. 3. Coadministration of cotrimoxazole with loperamide significantly increased the Cmax (0.74 +/- 0.22 ng ml-1 without cotrimoxazole; 1.49 +/- 0.81 ng ml-1 with cotrimoxazole; P < 0.01) and AUC (13.40 +/- 3.80 ng ml-1 h without cotrimoxazole; 25.30 +/- 11.10 ng ml-1 h with cotrimoxazole; P < 0.005) of loperamide, whilst its tmax and t1/2,z were not significantly altered. 4. The increase in loperamide AUC, following coadministration of either loperamide oxide or loperamide with cotrimoxazole, may be due to reduced first pass metabolism of loperamide.

Administration, Oral↗
PubMed1996

Coinfection with human herpesvirus 6 variants A and B in lung tissue.

Human herpesvirus 6 (HHV-6) variant B is frequently identified in peripheral blood, but identification of HHV-6 variant A is relatively rare. We devised a PCR-based method for sensitive, simultaneous detection of both HHV-6 variants. The method was applied to 34 lung tissue specimens that were previously shown to contain HHV-6 DNA. A total of 22 lung tissue samples showed coinfections with HHV-6 variants A and B, 2 had only HHV-6 variant A DNA, and 10 had only HHV-6 variant B DNA. The prevalences of coinfections in lung tissues from healthy controls (54% coinfected) and in those from bone marrow transplant patients with pneumonia (67% coinfected) were similar. These data indicate that coinfections of HHV-6 variants A and B commonly occur in lung tissues of healthy and diseased individuals.

Base Sequence↗
PubMed1995

CD28 ligands CD80 (B7-1) and CD86 (B7-2) induce long-term autocrine growth of CD4+ T cells and induce similar patterns of cytokine secretion in vitro.

The interaction of CD28 and its ligands is critical for antigen-induced T cell activation. Recent studies have demonstrated the existence of at least two members of the B7 receptor family. In this report, the co-stimulatory signals provided by CD80 (B7-1) or CD86 (B7-2) were compared to CD28 ligation by mAb. We demonstrate that the kinetics of induction of T cell proliferation after anti-CD3 stimulation was similar regardless of the form of co-stimulation. Similarly, B7-1 and B7-2 could both maintain long-term expansion of CD4 cells. The co-stimulatory effects of both B7-1 and B7-2 were dependent on CD28 cross-linking, based on complete inhibition of proliferation by CD28 antibody Fab fragments. Co-stimulation with B7-1 and B7-2 induced high levels of cytokine secretion by resting T cells, and the effects of B7-1 and B7-2 could not be distinguished. This conclusion is based on analysis of the initial activation of CD28+ T cells, as well as T cell subpopulations consisting of CD4+ and CD8+ T cells. Both B7-1 and B7-2 could elicit IL-4 secretion from CD4+ T cells while anti-CD28 antibody induced substantially less IL-4 secretion. Furthermore, both B7-1 and B7-2 could stimulate high levels of IFN-gamma and IL-4 from CD4+CD45RO+ cells, while neither B7 receptor could co-stimulate IFN-gamma and IL-4 secretion from CD4+CD45RA+ T cells. B7-1 and B7-2 could, however, co-stimulate CD4+CD45RA+ T cells to secrete IL-2. By contrast, when previously activated T cells were tested, re-stimulation of CD4+ T cell blasts with B7-1 or B7-2 resulted in higher secretion of IL-4 and IL-5 than anti-CD28, while re-stimulation with anti-CD28 antibody maintained a higher level of secretion of IL-2 and IFN-gamma than B7-1 or B7-2. These observations may have important implications because they suggest that the manner of CD28 ligation can be a critical determinant in the development of cytokine secretion that corresponds to Th1- and Th2-like patterns of differentiation. Together these observations suggest that there are no intrinsic differences between B7-1 and B7-2 in their ability to co-stimulate the populations of cells that we have tested.

Animals↗
PubMed1995

Both CD28 ligands CD80 (B7-1) and CD86 (B7-2) activate phosphatidylinositol 3-kinase, and wortmannin reveals heterogeneity in the regulation of T cell IL-2 secretion.

In this report, the co-stimulatory signals provided by CD80 (B7-1) or CD86 (B7-2) were compared to CD28 ligation by mAb. We demonstrate that while both anti-CD3 and anti-CD28 antibodies induced activation of phosphoinositide (PI) 3-kinase, the kinetics of activation differed. Anti-CD28 produced a sustained activation of PI 3-kinase while anti-CD3 induced activation was transient. Both B7-1 and B7-2 could induce prolonged activation of PI 3-kinase. The co-stimulatory effects of B7-1 and B7-2 were dependent on CD28 cross-linking, based on complete inhibition of PI 3-kinase activation by CD28 antibody Fab fragments. While Jurkat T cells co-stimulated with anti-CD3 and B7-1 or B7-2 secreted high levels of IL-2, there were distinct effects of anti-CD28 mAb and B7-1 or B7-2 on IL-2 secretion in conjunction with protein kinase C activation. To assess functional effects of CD28 ligation, pharmacologic inhibitors of PI 3-kinase were evaluated. In Jurkat cells, efficient inhibition of PI 3-kinase activation after B7-2 stimulation was achieved using wortmannin; however, we observed a surprising increase in IL-2 secretion after B7 or anti-CD28 stimulation. The effect of wortmannin was concentration dependent. Moreover, the effect was specific for receptor-mediated activation as wortmannin did not enhance phorbol ester plus ionomycin-induced IL-2 secretion. Another inhibitor of PI 3-kinase, LY294002, also resulted in augmentation of anti-CD28-induced IL-2 secretion by Jurkat cells. The effects of wortmannin on IL-2 secretion were also examined in primary T cells. In marked contrast, wortmannin resulted in a potent inhibition of anti-CD3 plus B7-1 or anti-CD28-induced IL-2 secretion while phorbol ester plus ionomycin-induced IL-2 secretion was wortmannin resistant. Together these observations demonstrate that signal transduction by both B7-1 and B7-2 involves PI 3-kinase, and that PI 3-kinase or other wortmannin-sensitive targets are important for IL-2 secretion. Finally, treatment of Jurkat cells with PI 3-kinase inhibitors alone was sufficient to induce low levels of IL-2 secretion. This is consistent with the notion that a wortmannin-sensitive target such as PI 3-kinase may down-regulate IL-2 secretion in Jurkat cells.

Androstadienes↗
PubMed1994

Mice expressing both B7-1 and viral glycoprotein on pancreatic beta cells along with glycoprotein-specific transgenic T cells develop diabetes due to a breakdown of T-lymphocyte unresponsiveness.

T lymphocytes have been implicated in the onset of many autoimmune diseases; however, the mechanisms underlying T-cell activation toward self antigens are poorly understood. To study whether T-lymphocyte costimulation can overcome the immunologic unresponsiveness observed in an in vivo model, we have created transgenic mice expressing the costimulatory mouse molecule B7-1, a ligand for the CD28 receptor, on pancreatic beta cells. We now report that triple-transgenic mice expressing both B7-1 and a viral glycoprotein on their beta cells, along with T cells expressing the viral-glycoprotein-specific transgenic T-cell receptor, all develop insulitis (lymphocytic infiltration of the pancreatic islets) and diabetes. In striking contrast, the T cells in double-transgenic mice expressing the same viral glycoprotein (but no B7) on their pancreatic beta cells and the transgenic T-cell receptor on their T cells, reported earlier, remain indifferent to the glycoprotein-expressing beta cells. In fact, all three transgenes are required to initiate immune-mediated destruction of the beta cells. Mice expressing any of the transgenes alone, or any two in combination, maintain normal islet architecture and never spontaneously develop insulitis or diabetes. Our results show that aberrant B7 expression on peripheral tissues may play an important role in the activation of self-reactive T cells and further suggest that abnormal expression of costimulatory receptors may be involved in various T-cell-mediated autoimmune diseases.

Animals↗