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Biomedical subjects

R Ashley

Publications and source records attributed to R Ashley.

At least 55 records · Page 3Linked to original sources
PubMed1994

Ontogeny of glycoprotein gB-specific antibody and neutralizing activity during natural cytomegalovirus infection.

The envelope glycoprotein gB (gpUL55) is a candidate for inclusion in subunit cytomegalovirus (CMV) vaccines, although data on gB antibody responses after natural infection are limited. [35S]-labeled gB was partially purified from cells infected with an adenovirus recombinant expressing gB and used in radioimmunoprecipitation assays to characterize responses in solid organ transplant recipients with primary (n = 11) or secondary (n = 8) CMV infection. Seropositive transplant patients without evidence of infection (n = 5) and healthy seroconverters (n = 7) were also studied. gB antibody developed concurrently with CMV-specific IgG, IgM, and neutralizing activity in transplant patients with primary infection. Sustained boosts in gB antibody were seen in patients with secondary infection, and healthy seroconverters developed early gB responses. These data imply that gB antibody is an integral part of the humoral response to CMV infection, and, in view of experimental data regarding immunogenicity, support a role for gB in subunit vaccines.

Adult↗
PubMed1994

Human T cell lymphotropic virus type I infection among female sex workers in Peru.

Four hundred female sex workers attending a sexually transmitted disease clinic in Lima, Peru, were interviewed for demographic information and medical, contraceptive, and sexual practice histories. Cervical cultures were done for Neisseria gonorrhoeae and Chlamydia trachomatis, and serum was tested for antibodies to human immunodeficiency virus, human T cell lymphotropic virus type I (HTLV-I), Treponema pallidum, C. trachomatis, herpes simplex virus type 2 (HSV-2), and Haemophilus ducreyi. The prevalence of HTLV-I increased with duration of prostitution from 3.6% (< 3 years) to 9.3% (3-6 years) to 15.9% (> 6 years; P < .01). After adjustment for duration of prostitution, reduced risk of HTLV-I was significantly correlated with condom use for more than half of all sexual exposures for > 3 years (odds ratio [OR], 0.34; 95% confidence interval [CI], 0.13-0.89). Further adjusting for condom use, HTLV-I seropositivity was associated with C. trachomatis (OR, 3.7; 95% CI, 1.4-13.2) and with antibody to HSV-2 (OR, 3.7; 95% CI, 0.5-29.6). Thus, duration of prostitution, lack of consistent condom use, and past infection with C. trachomatis were significantly associated with HTLV-I seropositivity.

Adult↗
PubMed1994

Prevalence and epidemiologic correlates of human T cell lymphotropic virus infection among intravenous drug users.

Intravenous drug users (IVDUs) in Seattle (n = 213) were studied to identify the prevalence and predominant types of and risk factors for human T cell lymphotropic virus (HTLV) infection. Detailed questionnaires, serologic screening, and polymerase chain reaction analysis (for a subset) were used. Evidence of HTLV infection was found in 16.5%, of which 89% were HTLV-II. HTLV infection was significantly associated with nonwhite race, older age, more years of intravenous drug use, prior use of heroin, history of gonorrhea, history of any sexually transmitted disease, hepatitis B virus infection, and antibody to herpes simplex virus type 2 (HSV-2). By stepwise logistic regression analysis, associations persisted with race, age, hepatitis B markers, and HSV-2. Thus, the strong association of HTLV with hepatitis B, a marker for injection behavior, and the independent association with HSV-2 infection, a sexually transmitted pathogen, suggest similarities in the epidemiology of HTLV and human immunodeficiency virus infections in IVDUs.

Adult↗
PubMed1994

Cervical antibodies in patients with oral herpes simplex virus type 1 (HSV-1) infection: local anamnestic responses after genital HSV-2 infection.

Herpes simplex virus (HSV)-specific immunoglobulin A, immunoglobulin G, and secretory-component-containing immunoglobulins were identified in cervical and salivary secretions from six subjects with oral HSV type 1 (HSV-1) infections. Anamnestic cervical and salivary antibody responses were detected in two HSV-1-seropositive women with newly acquired genital HSV-2 infections. These data implicate the common mucosal immune system in antibody responses to HSV.

Adult↗
PubMed1994

Detection of rectal antibodies to HIV-1 by a sensitive chemiluminescent western blot immunodetection method.

Western blot with a time-dependent enhanced chemiluminescence immunodetection method (ECL-WB) was shown to be 100-fold more sensitive than standard commercial colorimetric Western blots (WB) for detecting serum IgG to human immunodeficiency virus type 1 (HIV-1). ECL-WB was then used to test rectal secretions from 15 HIV-1 infected subjects (HIV+) and 7 uninfected subjects (HIV-) to document local IgG, IgA, and secretory component-associated immunoglobulin (SC-Ig) to HIV-1 proteins. Fourteen of 15 HIV+ subjects had rectal IgA to at least 1 HIV-1 protein, most often to gp41 (80%) or p24 (60%) and 14 (93%) had IgG to gp160, gp120, or gp41. Of seven HIV- subjects, none had detectable bands to HIV-1 proteins. SC-Ig to HIV-1 proteins was detected in all five rectal samples tested. However, the antibody profiles differed from those of rectal IgA, suggesting more than one source of rectal IgA to HIV. ECL-WB requires individual optimization and interpretation for each specimen as well as expensive reagents and is, therefore, not currently applicable to screening assays. However, the method offers promise as a sensitive method to characterize low-level immune responses (IgG, IgA, and SC-Ig) to HIV-1 proteins at local sites such as rectal mucosae.

Blotting, Western↗
PubMed1993

The effect of local anaesthetics on the ryanodine receptor/Ca2+ release channel of brain microsomal membranes.

The effects of various local anaesthetics (LAs) on ryanodine binding of the sheep brain ryanodine receptor were tested. Tetracaine and dibucaine inhibit the binding with half-maximal inhibition (CI50) of 0.12 mM and 0.7 mM, respectively. Lidocaine and its analog QX-314, on the other hand, stimulate the binding up to 3-fold with half-maximal stimulation occurring with about 2 mM of the drugs. Lidocaine increases both the receptor affinity for ryanodine by about 5-fold and the rate of ryanodine association with its binding site by about 6-fold. Tetracaine and lidocaine also interact with the purified brain ryanodine receptor and produce inhibitory and stimulatory effects similar to those obtained with the membrane-bound receptor. The interaction of the LAs with the brain ryanodine receptor, as well as with the skeletal muscle receptor [J. Memb. Biol. 133 (1993) 171-182], suggest that ryanodine receptor possesses intrinsic binding site(s) for LAs.

Anesthetics, Local↗
PubMed1993

Human herpesvirus 6 in lung tissue from patients with pneumonitis after bone marrow transplantation.

BACKGROUND: Human herpesvirus 6 (HHV-6) is a recently described herpesvirus that is epidemiologically and biologically similar to cytomegalovirus. It is the cause of exanthem subitum (roseola) in children. METHODS: To evaluate the possible role of HHV-6 infection in pneumonitis in immunocompromised patients, we used quantitative HHV-6 polymerase chain reactions to study lung-biopsy specimens from 15 patients with pneumonitis after bone marrow transplantation and lung tissue from 15 immunocompetent subjects without pneumonitis and 6 fetuses. RESULTS: HHV-6 DNA was detected in lung tissue from all 15 patients, from 14 seropositive control subjects, and from none of the 7 seronegative control subjects. Six patients had levels of HHV-6 DNA in lung tissue that were 10 to 500 times higher than those in any of the other patients or control subjects. Increased levels of HHV-6 DNA correlated with a decreased risk of death from pneumonitis (P = 0.015), an increased severity of graft-versus-host disease (P = 0.023), and the presence of idiopathic pneumonitis (P = 0.037). Levels of HHV-6 DNA correlated directly with the changes in HHV-6 antibody titers in the interval between the pretransplantation period and the open-lung biopsy (P = 0.002). Low levels of HHV-6 antibody at the time of the open-lung biopsy were also associated with the diagnosis of idiopathic pneumonitis (P = 0.002). CONCLUSIONS: The concentrations of HHV-6 genome in lung tissue and their relation to changes in serologic titers support an association between HHV-6 infection and idiopathic pneumonitis in immunocompromised hosts.

Adolescent↗
PubMed1993

Failure to detect Epstein-Barr virus DNA in peripheral blood mononuclear cells of most patients with large granular lymphocyte leukemia.

Clonal disease of large granular lymphocytes (LGLs) may arise from either CD3+ LGLs (LGL leukemia) or CD3- LGLs (natural killer [NK] cell leukemia). Other patients have chronic LGL proliferations that cannot be proven to be clonal (lymphoproliferative disease of granular lymphocytes [LDGL]). It was recently shown that clonally expanded CD3- LGLs from Japanese patients contain Epstein-Barr virus (EBV) DNA sequences, arguing for a direct causative role for EBV in NK cell leukemia. The aggressive clinical course and other clinical features of these Japanese patients differ markedly from the clinical features of LGL leukemia and CD3- LDGL patients in the United States and Europe, suggesting different pathogenic mechanisms. Therefore, we performed serologic and DNA hybridization studies for EBV in 31 patients from the United States and Europe (18 with LGL leukemia and 13 with chronic CD3- LDGL). All patients had serologic evidence for past infection with EBV. We did not detect EBV DNA sequences in peripheral blood mononuclear cell DNA from any of these patients in Southern blot hybridization analyses. EBV DNA sequences were detected after polymerase chain reaction amplification of peripheral blood mononuclear cell DNA in only 2 of 18 LGL leukemia patients and 4 of 13 chronic CD3- LDGL patients. These results argue against a direct causative role for EBV infection in LGL leukemia or chronic CD3- LDGL occurring in the United States and Europe.

Base Sequence↗
PubMed1993

The interaction of fluorescein isothiocyanate with the ryanodine receptor/Ca2+ release channel of sarcoplasmic reticulum.

Fluorescein 5'-isothiocyanate (FITC) markedly inhibited ryanodine binding to rabbit skeletal muscle junctional sarcoplasmic reticulum. Half-maximal inhibition was obtained with about 20 microM and complete inhibition by 80 microM FITC. Inhibition was enhanced in the presence of high salt and at alkaline pH. The pH dependence of the inactivation of ryanodine binding suggested that FITC bound to a very reactive lysine epsilon-amino group with a pK alpha of about 7.5 or above. Kinetic analysis of the time course of inactivation of ryanodine binding by various concentrations of FITC suggested that the inactivation resulted from the modification of 2 or more amino acid residues. The inhibition of ryanodine binding by FITC was partially prevented by ATP, ADP, adenyl imidodiphosphate, and 3-O-(benzoyl)-benzoyl-ATP (Bz-ATP) but not by AMP. FITC modification of sarcoplasmic reticulum membranes inhibited the photoaffinity labeling by [alpha-32P]Bz-ATP of the 450-kDa protein and the ryanodine receptor with half-maximal inhibition at about 100 microM. The results suggest that the inhibition of ryanodine binding is mainly due to FITC modification of sites which are not involved in ATP binding. The FITC moiety is bound to the 160-, 96-, 76-, and 60-kDa ryanodine receptor tryptic fragments, and the FITC site is apparently on the 21.5-, 18-, and 17-kDa fragments which are formed by the V8 protease. Covalent modification by FITC dramatically affected the activity of single Ca2+ release channels incorporated into planar lipid bilayers. FITC caused a marked increased in channel open probability mainly to a noisy approximately 60% subconductance state. FITC-modified channels were no longer affected by ryanodine but were still abolished by Mg2+ and ruthenium red. We suggest that FITC modifies reactive lysine residues involved in channel activation by transmembrane charge movement in the t-tubular system.

Adenine Nucleotides↗
PubMed1993

Human herpesvirus 6 DNA in peripheral blood cells and saliva from immunocompetent individuals.

Human herpesvirus 6 (HHV-6) genome equivalents were quantitated in peripheral blood mononuclear cells (PBMCs) and saliva from 20 healthy individuals by the polymerase chain reaction (PCR). Nineteen of 20 subjects (95%) harbored HHV-6 DNA: 18 (90%) had HHV-6 in their PBMCs and 18 had HHV-6 in their saliva. Quantitative PCR revealed HHV-6 DNA levels ranging from negative to 4,000 HHV-6 genome equivalents per 10(6) PBMCs and from negative to 200,000 HHV-6 genome equivalents per ml of saliva. Longitudinal saliva samples from 15 HHV-6-seropositive subjects revealed salivary HHV-6 DNA persistence in 13 subjects. HHV-6 antibodies were detected in 17 of 19 subjects, with titers ranging from 1:400 to 1:51,200 (geometric mean titer, 1:2,500). Antibody titers did not correlate with HHV-6 DNA levels in PBMCs or saliva (P = 0.27 and P = 0.44, respectively). One subject with persistent HHV-6 DNA lacked detectable HHV-6 antibodies. The high prevalence of HHV-6 DNA in PBMCs and saliva supports the concept that HHV-6 exists at these sites in normal individuals.

Adult↗
PubMed1992

Risk factors for the sexual transmission of genital herpes.

OBJECTIVE: To determine the risk of sexual transmission of genital herpes simplex virus (HSV) in heterosexual couples. DESIGN: Prospective study of couples who were participants in a clinical trial. Each source partner had symptomatic, recurrent genital HSV, and each susceptible partner was without serologic or clinical evidence of genital herpes. Couples were followed for a median of 334 days. SETTING: Two university-based research clinics. PATIENTS: One hundred forty-four heterosexual couples were studied out of an initial enrollment of 214 couples. MAIN OUTCOME MEASURES: Development of culture-proven HSV infection or type-specific antibodies in the susceptible partner. MAIN RESULTS: Transmission occurred in 14 (9.7%) couples, including 11 (16.9%) of 65 couples with male and 3 (3.8%) of 79 with female source partners (P = 0.05). The annual rate of acquisition was higher (31.8%) in susceptible female partners who lacked antibodies to either HSV type 1 or 2 at entry compared with females with HSV type 1 antibodies at entry (9.1%). Couples avoiding transmission of HSV reported fewer days with genital lesions in source partners. Detailed histories were available at the time of transmission in 13 couples. In nine couples, transmission occurred when the source partner was reported to be asymptomatic and in four, it resulted from sexual contact at the time of prodrome (1 case) or within hours before lesions were first noticed by the source partner (3 cases). CONCLUSIONS: Despite clear recognition of genital herpes in source partners, there was substantial risk for transmission; in 70% of patients, transmission appeared to result from sexual contact during periods of asymptomatic viral shedding. The risk for acquisition of HSV was higher in women than men, and previous HSV type 1 infection appeared to reduce the risk for acquisition of HSV type 2 infection among women.

Adult↗
PubMed1992

Diminished interferon-gamma and lymphocyte proliferation in neonatal and postpartum primary herpes simplex virus infection.

Interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha production and lymphocyte proliferation in response to herpes simplex virus (HSV) antigen were assessed in 13 neonates and 3 parturient women with primary HSV infection. In comparison with 9 nonparturient adults, the neonates and parturient women showed significantly (P less than .01) diminished HSV antigen-stimulated lymphocyte proliferation and IFN-gamma production in the first 3-6 weeks after onset of infection. TNF alpha production did not differ significantly among HSV-infected groups. The impairment in neonatal cellular immunity was due, at least in part, to a specific deficit in response to HSV antigen. Lymphocyte proliferation and TNF alpha production in response to the mitogen concanavalin A (ConA) were comparable in adults and infants, but ConA-stimulated IFN-gamma production in infants was diminished throughout the study period. In contrast, HSV antigen-stimulated IFN-gamma production was comparable in infants and adults after 6 weeks. Not all patients with diminished cellular immune responses to HSV antigen manifested severe clinical disease. Nevertheless, patients with significant clinical morbidity had diminished cellular immune responses to HSV antigen. These results suggest that delayed acquisition of antigen-specific cellular immunity in primary HSV infection predisposes to more severe clinical disease.

Antibodies, Viral↗
PubMed1992

Highly sensitive enhanced chemiluminescence immunodetection method for herpes simplex virus type 2 Western immunoblot.

Three Western blot (immunoblot) methods for detecting antibodies to herpes simplex virus type 2 were compared: (i) nitrocellulose blots with 4-chloro-1-naphthol immunostaining (4CN-WB); (ii) polyvinylidene difluoride (PVDF) blots with 3,3',5,5'-tetramethylbenzidene immunostaining (TMB-WB); and (iii) PVDF blots with enhanced chemiluminescence (ECL-WB). TMB-WB was 10-fold more sensitive than 4CN-WB, while ECL-WB was as much as 500-fold more sensitive.

Antibodies, Viral↗
PubMed1992

Comparison of the Western immunoblot assay and a glycoprotein G enzyme immunoassay for detection of serum antibodies to herpes simplex virus type 2 in patients with AIDS.

Herpes simplex virus type 2 (HSV-2) seroprevalence in 68 patients with AIDS was 77% by Western blot (immunoblot) and 44% by glycoprotein G-2 immunoassay. Each of 16 patients with culture-proven HSV-2 infection was positive by Western blot versus 8 by glycoprotein G-2 immunoassay. No differences in age, race, duration of AIDS, acyclovir usage, or HSV-1 seroprevalence were found to explain differences in sensitivity.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Inability of enzyme immunoassays to discriminate between infections with herpes simplex virus types 1 and 2.

OBJECTIVE: To determine the accuracy of three commercial enzyme immunoassays in detecting and subtyping antibodies to herpes simplex virus type 1 or 2. DESIGN: Cross-sectional. SETTING: Referral medical center. PATIENTS: Ninety patients with culture-positive lesions caused by infection with herpes simplex virus type 1 or 2. The results of Western blot and glycoprotein G immunodot enzyme assays showed that an additional 53 patients had subclinical herpes simplex virus 2 infection, that another 20 patients had subclinical herpes simplex virus type 1 infection, and that 23 patients were seronegative. MEASUREMENTS: Three commercial enzyme immunoassays were used to determine herpes simplex virus antibody subtypes. MAIN RESULTS: All three commercial assays performed poorly in all patient groups (except in patients who were seronegative for herpes simplex virus). Among the 40 patients with a first episode of genital herpes, seroconversion to the appropriate viral type was shown by the three assays in only 33%, 55%, and 75% of cases. Among patients with recurrent genital herpes, the three commercial assays identified more than 90% of patients with only herpes simplex virus type 2 antibodies but failed to identify herpes simplex virus type 2 infections in 58% to 76% of patients with antibodies to both virus subtypes. The three assays correctly identified only 55%, 75%, and 85% of the 53 "silent carriers" of herpes simplex virus type 2. Overall, the three enzyme immunoassays detected herpes simplex virus type 2 antibodies in 60%, 62%, and 93% of patients with subtype 2 infections and falsely detected type 2 antibodies in 8%, 27%, and 49% of patients with type 1 infections. CONCLUSION: Currently licensed enzyme immunoassays give inaccurate or misleading results about the correct herpes simplex virus infecting subtype.

Antibodies, Viral↗
PubMed1991

Neonatal herpes simplex virus infection in relation to asymptomatic maternal infection at the time of labor.

BACKGROUND AND METHODS: To define the risk factors associated with neonatal acquisition of herpes simplex virus (HSV) infection, we prospectively obtained HSV cultures from the cervix and external genitalia of 15,923 pregnant women in early labor who were without symptoms or signs of genital HSV infection. Follow-up of the women with positive cultures for HSV and their HSV-exposed infants included serologic tests and serial cultures for HSV. RESULTS: HSV was isolated from 56 of the women (0.35 percent), 18 of whom (35 percent) had serologic evidence of a recently acquired, subclinical first episode of genital HSV infection, and 34 of whom (65 percent) had reactivation of HSV. Neonatal HSV developed in 6 of 18 infants (33 percent) born to the women with a first episode of genital HSV, and in 1 of 34 infants (3 percent) born to the women with reactivation of HSV (P less than 0.01); neonatal HSV also occurred in three of the infants born to the 15,867 women with negative cultures. Neonatal HSV-2 occurred in 1 of 4 infants born to mothers seronegative at delivery for both HSV-1 and HSV-2, in 4 of 12 infants exposed to HSV-2 whose mothers had only HSV-1 antibodies at delivery, and in none of the infants born to 31 women who were HSV-2-seropositive. An increased risk of neonatal HSV was associated with exposure to viral shedding from the cervix and the use of fetal-scalp electrodes. CONCLUSIONS: Of the asymptomatic women who shed HSV in early labor, about a third have recently acquired genital HSV, and their infants are 10 times more likely to have neonatal HSV than those of women with asymptomatic reactivation of HSV. The presence of maternal antibodies specific to HSV-2 but not HSV-1 appears to reduce the neonatal transmission of HSV-2. Further studies are necessary to determine whether screening and prophylactic treatment are warranted for infants of HSV-2-seronegative mothers who shed HSV-1 or HSV-2 in early labor.

Antibodies, Viral↗