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Biomedical subjects

G E Gray

Publications and source records attributed to G E Gray.

At least 19 recordsLinked to original sources
PubMed2000

Pediatric admissions with human immunodeficiency virus infection at a regional hospital in Soweto, South Africa.

The prevalence and clinical spectrum of HIV disease in hospitalized African children has not been adequately characterized in Southern Africa. This study aimed to determine the prevalence and disease profile of HIV infected children under 5 years of age admitted to a tertiary care hospital in Soweto, South Africa and to assess the impact of pediatric HIV on health services. Over a 6-month period, serial pediatric admissions to one of the children's wards were screened for HIV. Data on demographics and disease profile were recorded for all patients. A total of 549 patients were admitted, of whom 507 were tested for HIV; 29.2 per cent were considered to be truly infected. Previous admissions to hospital were more frequent in the HIV infected group, 48 per cent compared with 20.4 per cent of HIV uninfected children (p < 0.01), with a median length of stay of 8 days compared with 6 days (p < 0.01). There were more malnourished children in the HIV infected group (65.8 per cent compared with 33.1 per cent) (p < 0.01) and more died (17 per cent compared with 4.6 per cent) (p < 0.01). The most common reasons for admission in all children were infectious diseases such as pneumonia and gastroenteritis (85 and 31.9 per cent compared with 51 and 22.5 per cent, respectively in the HIV infected and uninfected groups, p < 0.01 and p < 0.03). It was concluded that pediatric HIV infection accounts for almost a third of childhood admissions to this hospital and has become a significant burden on the health service.

AIDS-Related Opportunistic Infections↗
PubMed2000

A review of herbal medicines for psychiatric disorders.

OBJECTIVE: This review examines herbs commonly used for psychiatric symptoms-St. John's wort, kava, ginkgo biloba, and valerian. METHODS: MEDLINE was searched for articles related to the use of herbs in psychiatry published after 1990. A secondary search examined sources cited in articles obtained from the MEDLINE search. RESULTS: Of nine controlled and standardized trials of St. John's wort, five showed the herb's superiority to placebo, and four found no differences in effectiveness when compared with antidepressant drugs. The pharmacologically active components are not known. Several double-blind, placebo-controlled trials have demonstrated the anxiolytic efficacy of kava, but these studies had ill-defined patient populations, small sample sizes, and short treatment duration. All but one of 40 controlled trials of ginkgo extracts in the treatment of dementia found clinically significant improvement in memory loss, concentration, fatigue, anxiety, and depressed mood. Most studies of gingko had poorly defined patient populations and small sample sizes and used nonstandard measures. A recent well-designed multicenter study showed significantly less decline in cognitive function among patients with dementia receiving gingko. Valerian has been shown to decrease sleep latency and nocturnal awakenings and improve subjective sleep quality, but placebo effects were marked in some studies, and in some cases the beneficial effects were not seen until two to four weeks of therapy. CONCLUSIONS: Although evidence of the efficacy of herbal preparations in treating psychiatric conditions is growing, translating the results of efficacy studies into effective treatments for patients is hampered by the chemical complexity of the products, the lack of standardization of commonly available preparations, and the paucity of well-controlled studies.

Clinical Trials as Topic↗
PubMed2000

AZT blues.

Explore the source record for details and available documents.

Anti-HIV Agents↗
PubMed1999

Human ligands of the Notch receptor.

During development, the Notch signaling pathway is essential for the appropriate differentiation of many cell types in organisms across the phylogenetic scale, including humans. Notch signaling is also implicated in human diseases, including a leukemia and two hereditary syndromes known as Alagille and CADASIL. To generate tools for pursuing the role of the Notch pathway in human disease and development, we have cloned and analyzed the expression of three human homologues of the Notch ligands Delta and Serrate, human Jagged1 (HJ1), human Jagged2 (HJ2), and human Delta1 (H-Delta-1), and determined their chromosomal localizations. We have also raised antibodies to HJ1, and used these antibodies in conjunction with in situ hybridization to examine the expression of these ligands in normal and cancerous cervical tissue. We find that, as reported previously for Notch, the ligands are up-regulated in certain neoplastic tissues. This observation is consistent with the notion that Notch signaling is an important element in these pathogenic conditions, raising the possibility that modulation of Notch activity could be used to influence the fate of the cells and offering a conceivable therapeutic avenue.

Amino Acid Sequence↗
PubMed1999

Correlation between CD4+ lymphocyte counts, concurrent antigen skin test and tuberculin skin test reactivity in human immunodeficiency virus type 1-infected and -uninfected children with tuberculosis.

BACKGROUND: HIV-infected children are at high risk of developing tuberculosis after infection by Mycobacterium tuberculosis. Emphasis is placed on tuberculin skin testing (TST) for diagnosing tuberculosis in children; however, its value in HIV-infected children is controversial. OBJECTIVES: To determine whether concurrent antigen testing and/or CD4+ lymphocyte counts help in the interpretation of the TST in children with tuberculosis. METHODS: Children eligible for the study were diagnosed as having tuberculosis on clinical criteria. CD4+ lymphocyte counts and delayed-type hypersensitivity (DTH) test, using the CMI Multitest were performed when tuberculosis was diagnosed. RESULTS: One hundred thirty children were enrolled. Tuberculin reactivity was lower in HIV-infected children at all cutoff levels than in HIV-uninfected children (P < 0.0001). The positive predictive value of normal CD4+ lymphocyte counts in predicting tuberculin reactions of > or =5 mm (in HIV-1-infected) and > or =10 mm (in HIV-uninfected patients) were 50 and 80.3%, respectively (P < 0.0001). An intact DTH reaction to the CMI Multitest in predicting reactions of > or =5 mm and > or =10 mm to tuberculin in HIV-infected and -uninfected children were 55 and 76%, respectively (P < 0.001). Kwashiorkor was responsible for 53.3% of false-negative TST in HIV-uninfected children with normal CD4+ lymphocyte counts. CONCLUSION: TST is of limited value as an adjunct in diagnosing tuberculosis in HIV-infected children. CD4+ lymphocyte counts and concurrent DTH testing are not useful for predicting tuberculin reactivity in HIV-infected patients with tuberculosis.

AIDS-Related Opportunistic Infections↗
PubMed1999

A family of proteins implicated in axon guidance and outgrowth.

Rapid progress in the identification and characterization of axon guidance molecules and their receptors has left the field poised to explore the intracellular mechanisms by which signals are transduced into growth cone responses. The TUC (TOAD/Ulip/CRMP) family of proteins has emerged as a strong candidate for a role in growth cone signaling. The TUC family members reach their highest expression levels in all neurons during their peak periods of axonal growth and are strongly down-regulated afterward. When axonal regrowth in the adult is triggered by axotomy, TUC-4 is reexpressed during the period of regrowth. Mutations in unc-33, a homologous nematode gene, lead to severe axon guidance errors in all neurons. Furthermore, the TUC family is required for the growth cone-collapsing activity of collapsin-1. An important role for the TUC family is also suggested by its high degree of interspecies amino acid sequence identity, with the rat TUC-2 protein showing 98% identity with its chick ortholog and 89% identity with its Xenopus ortholog. Information gained from the study of the TUC family will be of key importance in understanding how growth cones find their targets.

Animals↗
PubMed1997

Evaluation of the MUREX*ICE HIV-1.O.2 capture enzyme immunoassay for early identification of HIV-1 seroreverting infants in a developing country.

BACKGROUND: A simple, inexpensive serological assay is required for the early determination of HIV infection status among infants born to HIV-1-seropositive women in developing countries. OBJECTIVES: To evaluate the use of a commercially available capture enzyme immunoassay (EIA), the MUREX*ICE HIV-1.O.2, for the early identification of seroreverting, uninfected infants. STUDY DESIGN: Infants with a clearly defined HIV-1 infection status, as determined by polymerase chain reaction results and/or seroreactivity at 18 months, were tested for antibodies to HIV. The time to seroreversion using the capture EIA was compared with the results obtained using an indirect assay, the GENELAVIA MIXT EIA. RESULTS: Seroreverting infants were identified earlier with the capture than the indirect EIA; all of the uninfected infants were seronegative at 12 months with the capture EIA while 100% seroreversion was only seen at 18 months with the indirect EIA. CONCLUSIONS: In general, the capture EIA identified seroreverting infants 3-6 months earlier than the indirect EIA. However, caution must be exercised in interpreting seroreactivity in a breast-fed population where HIV infection may occur in a child who has previously seroreverted.

Africa↗
PubMed1993

Asian/non-Asian transcultural tricyclic antidepressant psychopharmacology: a review.

1. Transcultural psychopharmacology is a discipline that seeks to determine the relative importance of society, culture, environment, genetics, and biophysiology on the prescribing and metabolism of, and response to psychotherapeutic medications. 2. Studies and surveys comparing psychotropic medication use in Asian and non-Asian populations suggest that differences may exist in drug dosage requirements, plasma drug concentrations corresponding to therapeutic and toxic effects, and the incidence and severity of adverse drug reactions. 3. This paper reviews and critiques the published controlled studies on Asian/non-Asian transcultural tricyclic antidepressant psychopharmacology, provides guidelines for the use of psychotropic medications in Asian populations, and offers suggestions for future transcultural studies. 4. Anecdotal reports suggest that differences exist between Asian and non-Asian populations in the pharmacokinetics of tricyclic antidepressants. Controlled studies have not consistently supported this view. 5. Studies with larger sample sizes and more rigorous controls are needed to determine if such differences do, in fact, exist.

Antidepressive Agents, Tricyclic↗
PubMed1992

Lineage of radial glia in the chicken optic tectum.

In many parts of the central nervous system, the elongated processes of radial glial cells are believed to guide immature neurons from the ventricular zone to their sites of differentiation. To study the clonal relationships of radial glia to other neural cell types, we used a recombinant retrovirus to label precursor cells in the chick optic tectum with a heritable marker, the E. coli lacZ gene. The progeny of the infected cells were detected at later stages of development with a histochemical stain for the lacZ gene product. Radial glia were identified in a substantial fraction of clones, and these were studied further. Our main results are the following. (a) Clones containing radial glia frequently contained neurons and/or astrocytes, but usually not other radial glia. Thus, radial glia derive from a multipotential progenitor rather than from a committed radial glial precursor. (b) Production of radial glia continues until at least embryonic day (E) 8, after the peak of neuronal birth is over (approximately E5) and after radial migration of immature neurons has begun (E6-7). Radial glial and neuronal lineages do not appear to diverge during this interval, and radial glia are among the last cells that their progenitors produce. (c) As they migrate, many cells are closely apposed to the apical process of their sibling radial glia. Thus, radial glia may frequently guide the migration of their clonal relatives. (d) The population of labelled radial glia declines between E15 and E19-20 (just before hatching), concurrent with a sharp increase in the number of labelled astrocytes. This result suggests that some tectal radial glia transform into astrocytes, as occurs in mammalian cerebral cortex, although others persist after hatching. To reconcile the observations that many radial glia are present early, that radial glia are among the last offspring of a multipotential stem cell, and that most clones contain only a single radial glial cell, we suggest that the stem cell is, or becomes, a radial glial cell.

Animals↗
PubMed1991

Migratory paths and phenotypic choices of clonally related cells in the avian optic tectum.

We used retrovirus-mediated gene transfer to study the migration of clonally related cells in the developing chicken optic tectum. Clonal cohorts initially form radial arrays in the ventricular zone (approximately E5), but eventually divide into three separate migratory streams. In the first migration, a minor population of cells migrates tangentially along axon fascicles in medio-laterally directed files (approximately E6-E7); these eventually differentiate into multipolar efferent cells. After E7, the majority of cells in each clone migrate radially along fascicles of radial glia to form the tectal plate, wherein they differentiate into neurons and astrocytes. Around E9, a set of small cells leaves the radial arrays in superficial layers to form a second tangential migration; at least some of these differentiate into astrocytes. Thus, as the tectum develops, cells derived from a single multipotential precursor migrate along three separate pathways, follow separate guidance cues, and adopt distinct phenotypes.

Animals↗
PubMed1991

Saliva and plasma desipramine levels in Asian and Caucasian volunteers.

Thirty-seven healthy volunteers (18 Asian, 19 Caucasian) ingested a single desipramine (DMI) dose of 1.0 mg/kg of body weight. Saliva and plasma samples were obtained at 1, 3, 5, 7, 12, 24, 48, 72, and 96 hrs after dosing. A nested repeated-measures analysis of variance (ANOVA) design was used to determine if the plasma/saliva DMI ratio varied between Asians and Caucasians over time. Regression analysis was used to assess the ability of saliva DMI to predict plasma DMI at any time point. The ANOVA results indicated no significant differences in DMI plasma/saliva ratios between Asians and Caucasians. There was a major effect of sampling time on the DMI plasma/saliva ratio (p = 0.0001), with the ratio falling from 1.78 at 1 hr to 0.15 at 96 hrs. At any given time at least 24 hrs after the dose, there was a significant relationship between saliva and plasma levels across individuals. However, across subjects, the 95 percent confidence limits for predicting plasma DMI from saliva DMI levels were relatively large. The potential roles and limitations of saliva DMI in pharmacokinetic studies and clinical drug monitoring are discussed.

Adult↗
PubMed1990

Migratory patterns of clonally related cells in the developing central nervous system.

Neurons and glioblasts that arise in the ventricular zone migrate to form discrete nuclei and laminae as the central nervous system develops. By stably labeling precursor cells in the ventricular zone, pathways taken by different cells within an individual clone can be described. We have used recombinant retroviruses to label precursor cells with a heritable marker, the E. coli lacZ gene; clones of lacZ-positive cells are later mapped histochemically. Here we review results from three regions of the chicken central nervous system--the optic tectum, spinal cord, and forebrain--and compare them with previous results from mammalian cortex and other regions of the vertebrate CNS. In particular, we consider the relationship between migratory patterns and functional organization, the existence of multiple cellular sources of migratory guidance, and the issue of whether a cell's choice of migratory pathway influences its ultimate phenotype.

Animals↗
PubMed1990

Neurons and glia arise from a common progenitor in chicken optic tectum: demonstration with two retroviruses and cell type-specific antibodies.

We used a recombinant retrovirus to study cell lineage in the chicken optic tectum. The virus inserts the Escherichia coli lacZ (beta-galactosidase) gene into the genome of an infected cell; a histochemical stain marks the progeny of infected cells with a blue precipitate. We had previously shown that individual clones frequently contain diverse neuronal types. Now we asked whether individual clones contain glia as well as neurons. To this end, we constructed a virus in which lacZ is fused to a nuclear localization signal sequence from the simian virus 40 large tumor antigen. Cells infected with this virus are marked with blue nuclei instead of blue somata. In embryos injected with a mixture of the two retroviruses, individual clusters contained cells with only one label type (nuclear or cytoplasmic), thus verifying that clusters of cells were clones. Furthermore, it was possible to immunostain the somata of cells that had blue nuclei, whereas the blue cytoplasmic precipitate hampered immunostaining. Together, these methods allowed us to show that some clones contained neurons (neurofilament-positive) and two types of glia (glutamine synthetase-positive and glial fibrillary acidic protein-positive). This result demonstrates the existence of a common progenitor for neurons and glia in optic tectum.

Animals↗