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Biomedical subjects

R J Whitley

Publications and source records attributed to R J Whitley.

At least 127 records · Page 7Linked to original sources

Apical expression of herpes simplex virus type 2 glycoproteins in human neuroblastoma cells.

The expression of herpes simplex virus type 2 (HSV-2) glycoproteins on the surface of human neuroblastoma cells has been investigated using Millipore Millicell culture plate inserts. Utilizing a modified radioimmunoassay, we learned that glycoproteins B, C, D, E, and I were expressed predominantly on the apical membrane domain of the infected neuroblastoma cells. The unidirectional transport of HSV-2 glycoproteins was substantiated by the analysis of extracellular glycoproteins released from neuroblastoma cells. The results suggest that the evaluated HSV-2 glycoproteins were transported primarily to the apical plasma membrane domain of human neuroblastoma cells.

Cell Membrane↗

Natural history and treatment of varicella-zoster in high-risk populations.

Rigorous clinical trials have established that both acyclovir and vidarabine favourably alter the clinical course of herpes zoster and chicken-pox in immunocompromised patients. In one comparative study, acyclovir was shown to be superior to vidarabine for zoster in bone marrow transplant recipients. These data, plus the fact that acyclovir is easier to administer than vidarabine, and perhaps less toxic, have made intravenous acyclovir the recognized drug of choice for treatment of herpes zoster in immunocompromised patients. Acyclovir sodium sterile powder received Federal Drug Administration (FDA) approval for this indication in 1990 in the United States. Since complications of zoster occur in only a minority of immunocompromised patients, most physicians would prefer to initiate therapy with an orally-administered drug and avoid the cost and inconvenience of hospitalization. Future studies will compare the efficacy and safety of orally administered bromovinyl arabinosyl uracil and acyclovir in treatment of varicella-zoster virus infections.

Acyclovir↗

Metabolic effects of high-carbohydrate, high-fiber diets for insulin-dependent diabetic individuals.

The metabolic effects of high-carbohydrate (70%), high-fiber (70 g) (HCHF) and low-carbohydrate (39%), low-fiber (10 g) (LCLF) diets were examined for 10 subjects with insulin-dependent diabetes mellitus (IDDM). After a 1-wk control period subjects on a metabolic ward were randomly allocated to HCHF or LCLF diets for 4 wk. After a 6-wk washout period subjects re-entered the metabolic ward for 4 wk on the alternate diet. Artificial-pancreas studies were performed on each diet for measurement of insulin requirements. Compared with the LCLF diet, the HCHF diet reduced basal insulin requirements (P less than 0.025), increased carbohydrate disposed of per unit insulin (P less than 0.0008), and lowered total (P less than 0.0004) and high-density-lipoprotein cholesterol (P less than 0.0013). Glycemic control and other lipid fractions did not differ significantly. These results suggest that in IDDM patients, HCHF diets enhance peripheral glucose disposal, decrease basal insulin requirements, and lower total cholesterol without altering glycemic control or triglycerides.

Adult↗

Use of brain biopsy for diagnostic evaluation of patients with suspected herpes simplex encephalitis: a statistical model and its clinical implications. NIAID Collaborative Antiviral Study Group.

Using the decision analysis technique and multivariate regression methods, a statistical model was established to define the utility of brain biopsy for diagnostic evaluation of patients with suspected herpes simplex encephalitis (HSE). Two strategies were compared: strategy I, brain biopsy with acyclovir (ACV) treatment for 10 days in biopsy-positive patients, and strategy II, ACV therapy without brain biopsy. Strategy I resulted in a greater 6-month survival rate when the likelihood of patients having HSE was less than 70%. Based on the current estimated prevalence of HSE (for patients with suspected HSE) of 35%, strategy I showed a slight advantage of a 3.2% increase in 6-month survival rate. An individual patient's chance of a positive brain biopsy can be predicted using a mathematical equation based on several important clinical assessments. This equation in conjunction with the decision analysis is a useful guide for the clinical management of patients with regard to brain biopsy.

Acyclovir↗

High-level viremia in adults and children infected with human immunodeficiency virus: relation to disease stage and CD4+ lymphocyte levels.

Sixty-eight adults and nine children infected with human immunodeficiency virus type 1 (HIV-1) were evaluated consecutively for the presence and amount of cell-free infectious virus in their plasma. Viremia was detected in 18 of 68 adults and in five of nine children; titers ranged from 10 to 100,000,000 TCID/ml plasma. Among the adults, none of 19 asymptomatic patients, 4 of 34 AIDS-related complex patients, and 14 of 15 AIDS patients had cell-free infectious virus in their plasma. None of 35 adult subjects with CD4+ lymphocyte counts greater than 400/mm3 were viremic, whereas 3 of 17 with 200-400 CD4+ lymphocytes/mm3 and 15 of 16 individuals with less than 200 CD4+ lymphocytes/mm3 were plasma viremic. In contrast to adults, each of five children infected with HIV-1 in utero or during the perinatal period were plasma viremic regardless of their CD4+ lymphocytes counts (range, 42-2227/mm3), duration of infection, or clinical stage; however, children infected by HIV-1 at older ages were less frequently plasma viremic. Therapy with zidovudine led to a 10- to 10(6)-fold decline in plasma HIV-1 TCID in all eight subjects studied before and after treatment.

Adult↗

Evaluation of a test based on baculovirus-expressed glycoprotein G for detection of herpes simplex virus type-specific antibodies.

An immunoblot assay for discrimination of antibodies to herpes simplex virus (HSV) types 1 and 2 was devised using extracts of recombinant-baculovirus-infected insect cells expressing HSV-1 or -2 glycoprotein G (gG1 or gG2). The assay was evaluated by comparing its results with those obtained by using an immunodot assay based on gG immunopurified from HSV-1- and HSV-2-infected cells. Each of 110 human serum specimens was tested blindly and independently three times. At a serum dilution of 1:20, the maximum specificities were 96% and 100% and the maximum sensitivities were 100% and 92% for gG1 and gG2, respectively. Reproducibility was 99% among readers and 95% among individually tested samples of each specimen. Results obtained in two laboratories from a different set of 15 serum specimens were in complete agreement, indicating the assay is accurate and reproducible. The ease of antigen production should allow the test to become widely available.

Animals↗

Herpes simplex virus infections of the central nervous system. Encephalitis and neonatal herpes.

Herpes simplex virus (HSV) infections are among the most commonly encountered in humans. Fortunately, the resulting diseases are more usually nuisances, such as recurrent fever blisters, rather than life threatening or morbidity inducing. Nevertheless, HSV can result in disease of the central nervous system (CNS) with attendant neurological complications. Examples of the latter include herpes simplex encephalitis (HSE) or neonatal HSV infection. The past decade has witnessed significant advances in our understanding of the pathogenesis of these 2 forms of disease and, even more importantly, their amenability to treatment. This review summarises our current understanding of the natural history, pathogenesis, presentation, and treatment of HSV infections of the CNS. Because of the life-threatening nature of herpes simplex infections of the CNS, particular attention is paid to clinical presentation and differential diagnosis of confounding entities which mimic herpes simplex encephalitis. The controversy of brain biopsy versus alternative noninvasive diagnostic procedures is discussed. Clinical presentation and, importantly, the lack of uniform clinical presentation, as well as the value of intervention with appropriate antiviral drugs such as aciclovir and vidarabine (adenine arabinoside, ara-A), are stressed. The clinical outcome of herpes simplex virus infections of the CNS with therapy is particularly relevant. In spite of early intervention with selective and specific inhibitors of viral replication, return to normal function is not always achieved. At the conclusion of this review, the reader should be aware of the potential value of therapy as well as the problems encountered with diagnosis and management of patients with herpes simplex virus infections of the CNS.

Encephalitis↗

Mapping of herpes simplex virus-1 neurovirulence to gamma 134.5, a gene nonessential for growth in culture.

The gene designated gamma 134.5 maps in the inverted repeats flanking the long unique sequence of herpes simplex virus-1 (HSV-1) DNA, and therefore it is present in two copies per genome. This gene is not essential for viral growth in cell culture. Four recombinant viruses were genetically engineered to test the function of this gene. These were (i) a virus from which both copies of the gene were deleted, (ii) a virus containing a stop codon in both copies of the gene, (iii) a virus containing after the first codon an insert encoding a 16-amino acid epitope known to react with a specific monoclonal antibody, and (iv) a virus in which the deleted sequences were restored. The viruses from which the gene was deleted or which carried stop codons were avirulent on intracerebral inoculation of mice. The virus with the gene tagged by the sequence encoding the epitope was moderately virulent, whereas the restored virus reacquired the phenotype of the parent virus. Significant amounts of virus were recovered only from brains of animals inoculated with virulent viruses. Inasmuch as the product of the gamma 134.5 gene extended the host range of the virus by enabling it to replicate and destroy brain cells, it is a viral neurovirulence factor.

Amino Acid Sequence↗

Expression of HSV-1 glycoproteins in tunicamycin-treated monkey kidney cells.

The role of glycosylation in transport and expression of HSV-1 glycoproteins on the surface of HSV-1-infected African green monkey kidney cells was investigated by using tunicamycin (TM). A concentration of 0.05 microgram/ml of TM inhibited the replication of HSV-1 by greater than 99%. Immunoblot analysis of TM-treated and virus-infected cells indicated that 0.05 microgram/ml of TM blocked the addition of N-linked oligosaccharides into glycoproteins B, C and D. An immunofluorescence assay of TM-treated (0.05 and 0.1 microgram/ml) and virus-infected cells demonstrated the presence of nonglycosylated gC, gD and a reduced amount of gB on the surface of infected cells. The results suggest that the addition of N-linked oligosaccharides on the studied HSV-1 glycoproteins was not necessary for their transport and expression on the virus-infected cell surface.

Animals↗

Rapid detection of herpes-simplex-virus DNA in cerebrospinal fluid of patients with herpes simplex encephalitis.

Herpes-simplex-virus (HSV) DNA in cerebrospinal fluid was amplified by use of the polymerase chain reaction and identified by hybridisation to a specific oligonucleotide probe. Specimens of cerebrospinal fluid (CSF) from 4 of 4 patients with herpes simplex encephalitis were positive for HSV DNA, whereas CSF specimens from 6 patients with other central-nervous-system infections were negative. This technique may expedite diagnosis of herpes simplex encephalitis.

Adult↗

Long-term cognitive sequelae of acyclovir-treated herpes simplex encephalitis.

Survival from untreated herpes simplex type 1 encephalitis is well known to be accompanied by severe cognitive impairments. Recently, acyclovir has been proven to be the most effective available treatment for this disease, with the expectation that it would appreciably reduce morbidity. We performed detailed assessments of four consecutive patients who received acyclovir in the early stages of biopsy-proven herpes encephalitis and who now have been followed up for 1.5 to 4 years. All four patients showed definite residual on either clinical or formal neuropsychological testing, most commonly dysnomia and impaired new learning for both verbal and visual material, even though three had normal performance on a standard clinical mental status test. All four patients were unable to function at their prior level of achievement. Therefore, despite early administration of acyclovir in herpes encephalitis, long-lasting neuropsychological residua are likely. Furthermore, cognitive deficits of prognostic importance may not be detected by clinical screening.

Acyclovir↗

Individual NK cell clones lyse both tumor cell targets and herpes simplex virus-infected fibroblasts in the absence of interferon.

The target specificity of natural killer (NK) cells for either tumor cells or virus-infected cells has been investigated. Lymphocyte clones with the surface phenotype of NK cells (CD3-, CD16+) were obtained by limiting dilution of peripheral blood mononuclear cells stimulated with PHA, Herpes simplex virus type 1 (HSV-1), or Varicella-Zoster antigens. Clones were maintained in media with recombinant interleukin 2 (IL-2). Both NK-sensitive (K562 cells) and NK-resistant (Raji cells) targets were lysed by three cloned lines of NK cells. The ability to lyse NK-resistant target cells was largely lost when the cloned lymphocytes were cultured overnight in the absence of IL-2. Effector cells from all three clones were also capable of specifically lysing HSV-1 infected human fibroblasts in comparison with uninfected fibroblasts. We also showed that lysis of HSV-1 infected targets by NK cloned cells was independent of interferons in the culture system.

Adult↗

In vivo behavior of genetically engineered herpes simplex viruses R7017 and R7020. II. Studies in immunocompetent and immunosuppressed owl monkeys (Aotus trivirgatus).

The genetically engineered herpes simplex virus strains R7017 and R7020 were tested in owl monkeys (Aotus trivirgatus) previously shown to model herpetic diseases of immunocompromised patients and neonates. In contrast to the lethal disease seen in monkeys receiving 100-1,000 plaque-forming units (pfu) of wild-type virus, inoculation of greater than or equal to 10(6) pfu of recombinant viruses produced local lesions and viral shedding but not disseminated disease. Latent recombinant viruses were recovered from some ganglia innervating the sites of inoculation. Monkeys protected from lethal infection with wild-type virus exhibit recurrent lesions that increase in frequency and severity after total lymphoid gamma irradiation (TLI). In contrast, monkeys immunosuppressed by TLI and inoculated with R7020 could not be differentiated from irradiated controls with respect to morbidity or mortality. Moreover, the virus was not transmitted from immunosuppressed infected females to normal male cage mates.

Animals↗

Novel pharmacological strategies in the treatment of life-threatening cytomegalovirus infections. Clinical experience with continuous infusion 9-(1,3-dihydroxy-2-propoxymethyl) guanine.

Two novel antiviral pharmacologic strategies were used for therapy of life- and sight-threatening cytomegalovirus (CMV) infection; these were continuous drug infusion by portable pump and individualized patient regimen. 9-(1,3-Dihydroxy-2-propoxymethyl)-guanine (DHPG), an active and recently licensed antiviral drug against cytomegalovirus infection, was administered to five immunocompromised patients with chorioretinitis (all patients), colitis (two), and pneumonitis (three). Through dosage escalation, correlations between plasma levels, toxicity (i.e., myelosuppression), and clinical benefit were ascertained for therapy of acute disease (pneumonitis) as well as long-term therapy (chorioretinitis). Resolution of viremia, pneumonitis, colitis, and chorioretinitis was accomplished with steady-state plasma levels of DHPG approximating the mean ID50 of CMV isolates. The most notable clinical benefit was survival from CMV pneumonia and stabilization of vision. Although no adverse toxicity occurred during the DHPG continuous long-term therapy, survival was limited by the underlying disease.

Acquired Immunodeficiency Syndrome↗