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Biomedical subjects

G Miller

Publications and source records attributed to G Miller.

At least 217 records · Page 12Linked to original sources
PubMed1993

Quantitative leukoviremia and immune complex-dissociated antigenemia as predictors of infection status in children born to mothers infected with human immunodeficiency virus type 1.

Four methods of culturing human immunodeficiency virus type 1 (HIV-1) from peripheral blood mononuclear cells and two serum antigen tests were assessed as predictors of infection status in children born to HIV-1-infected mothers. Of 36 infants whose cocultures were quantitative, all 15 who were deemed to be infected with HIV-1 (nine with symptoms, six without symptoms) by clinical criteria or persistence of Western blot reactive antibody had positive culture results, and all 21 uninfected seroreverters had negative culture results (sensitivity = 100%; specificity = 100%). Quantitative coculture was more sensitive than a technique in which cells were counted and stimulated with phytohemagglutin but not cocultivated with cells from seronegative donors, and more sensitive than two other qualitative techniques evaluated in samples from 80 children, in which cells were not enumerated before culture. The level of leukoviremia in children with symptoms did not differ appreciably from the level of leukoviremia in symptom-free infected children. Among those with positive results on quantitative coculture, only 40% also had free HIV-1 antigen in serum, whereas 86% had antigen in immune complexes. Among the methods evaluated, quantitative HIV-1 coculture was the best indicator of infection status in children.

AIDS Serodiagnosis↗
PubMed1993

In situ detection of lytic Epstein-Barr virus infection: expression of the NotI early gene and viral interleukin-10 late gene in clinical specimens.

Riboprobes that detect two genes expressed only during productive infection were developed to characterize the clinical spectrum of Epstein-Barr virus (EBV) lytic infection and identify diseases that may be responsive to antiviral drug therapy. The NotI antisense probe hybridizes to tandem repeats in the abundant early lytic cycle BHLF1 mRNA. Transcripts were detected in lytically infected cell lines, AIDS-associated oral hairy leukoplakia, bone marrow of a patient with virus-associated hemophagocytic syndrome, and spleen of an AIDS patient but not in EBV-positive primary central nervous system lymphomas or in circulating EBV-infected B cells from a patient with acute infectious mononucleosis. The viral (v) interleukin-10 (IL-10) probe hybridizes to the unique 5' end of the late lytic cycle BCRF1 mRNA, which encodes a protein homologous to the human cytokine IL-10. The vIL-10 probe detected transcripts in lytically infected cell lines and within the differentiated layers of oral hairy leukoplakia.

Adolescent↗
PubMed1993

Multiply resistant nontyphoidal Salmonella gastroenteritis in children.

From January, 1990, to December 31, 1990, 75 children with multiply resistant Salmonella gastroenteritis were studied at the Children's Hospital "Ricardo Gutierrez" of Buenos Aires. These children ranged from 1 month to 15 years of age. Infection was community-acquired in 20 (26.6%), nosocomially acquired in 50 (66.7%) and undetermined in 5. Thirty-nine (52%) had grossly bloody stools. Fever occurred at some point in the clinical course in 61 children (81.3%) with a duration of 1 to 33 days (mean, 6.7 days). The duration of diarrhea (1 to 69 days) was longer in those who developed complications (P < 0.001). Six (8%) developed enterocolitis (2 with bowel perforation), 1 had a pulmonary abscess and 8 (11.4%) had bacteremia; 4 children died (5.3%). Salmonella typhimurium was the most common serovar (85.3%). Ninety percent minimum inhibitory concentration studies demonstrated that all strains were resistant to ampicillin (> 128 micrograms/ml), cephalothin (> 128 micrograms/ml), cefuroxime (> 128 micrograms/ml), nalidixic acid (> 256 micrograms/ml), rifampin (> 256 micrograms/ml), gentamicin (> 256 micrograms/ml) and tobramycin (256 micrograms/ml); 77.3% of strains were resistant to ceftazidime (32 micrograms/ml), 97.6% to netilmicin (> 256 micrograms/ml), 92.8% to amikacin (256 micrograms/ml), 24.4% to isepamicin (32 micrograms/ml), 5.3% to chloramphenicol (4 micrograms/ml) and 2.7% to cefoxitin (2 micrograms/ml). The 90% minimum inhibitory concentration of cefotaxime and ceftazidime was reduced by the addition of clavulanate. Aggressive multiply resistant Salmonella strains are a major pediatric problem in Buenos Aires.

Adolescent↗
PubMed1993

Characterization and transcriptional regulation of the 2'-N-acetyltransferase gene from Providencia stuartii.

We have cloned the chromosomally encoded 2'-N-acetyltransferase gene [aac(2')-Ia] from Providencia stuartii. DNA sequence analysis of the cloned insert identified a single open reading frame, which is capable of encoding a protein with a predicted molecular mass of 20,073 Da. The deduced AAC(2')-Ia protein showed no significant homology to other proteins, including all of the AAC(3) and AAC(6') proteins. Primer extension analysis was used to identify the aac(2')-Ia promoter, which contained an unusual sequence (CTTTTT) at the -35 region. Expression of the aac(2')-Ia gene occurs at low levels in wild-type P. stuartii strains; therefore, they are aminoglycoside susceptible. We have isolated mutants with high-level AAC(2')-Ia expression at a frequency of 4.8 x 10(-6). Detailed analysis of one mutant demonstrated a 12.2-fold increase in the accumulation of aac(2')-Ia mRNA. In addition, the levels of beta-galactosidase expression from a plasmid-encoded aac(2')-lacZ transcriptional fusion were increased 11.5-fold in this mutant relative to those in an isogenic wild-type strain. These results suggested that a trans-acting factor, designated aar (for aminoglycoside acetyltransferase regulator), controls AAC(2')-Ia expression in P. stuartii.

Acetyltransferases↗
PubMed1993

Comparing regions of the Epstein-Barr virus ZEBRA protein which function as transcriptional activating sequences in Saccharomyces cerevisiae and in B cells.

The ZEBRA protein activates expression of Epstein-Barr virus early-lytic-cycle genes in human B lymphocytes. Here it is shown that ZEBRA also behaves as a sequence-specific transcriptional activator in Saccharomyces cerevisiae. Deletional mutagenesis defined three regions of ZEBRA that participate in activation in S. cerevisiae. These regions are designated YI (amino acids [aa] 1 to 25), YII (aa 51 to 102), and YIII (aa 228 to 245). Two of the three regions of the native ZEBRA protein act together to mediate activation when assayed on ZEBRA binding sites. However, when fused to the DNA binding domain of GAL4 and assayed on GAL4 binding sites, regions YII and YIII were each sufficient to confer activation in S. cerevisiae. Regions of ZEBRA which affected activation in S. cerevisiae were also required in human B lymphocytes. The amino-terminal region of ZEBRA (aa 1 to 98) was required for activation both in S. cerevisiae and in human B cells; deletion of the carboxy-terminal 18 aa also significantly reduced activation in both cell types. Thus, the behavior of ZEBRA in human B cells and S. cerevisiae suggests that the protein contains universal activation motifs that interact with conserved components of the transcription machinery. However, certain deletion mutants of ZEBRA containing mutations in the N-terminal region exhibited discordant behaviors in S. cerevisiae and in B cells. For example, deletion of ZEBRA aa 26 to 51 impaired activation to a great extent in B cells but had little or no effect in S. cerevisiae. The discordant mutants may reflect interactions with a variable domain of a conserved component or unique interactions with specialized components of the basal transcription apparatus in different cells.

B-Lymphocytes↗
PubMed1993

Systemic and mucosal humoral responses to Helicobacter pylori in gastric cancer.

The systemic IgG response to Helicobacter pylori was examined in 70 patients with gastric cancer. H pylori IgG antibodies were assayed by enzyme linked immunosorbent assay (ELISA), and serological recognition of H pylori antigens was characterised by western blotting. A percentage of 78.5 were seropositive by ELISA. Two of five patients under age 50 were seronegative. Positivity was unrelated to age, sex, tumour type, or site. Ninety one per cent of ELISA positive cancer patients recognised the H pylori cytotoxin associated 120 kilodalton (kD) protein, significantly more than a control group of 47 ELISA positive patients with non-ulcer dyspepsia (72%). Four of 15 ELISA negative cancer patients also showed recognition of this protein in western blots. Mucosal IgA responses to H pylori were examined by immunoblotting supernatants of in vitro cultured resected antral mucosa in an overlapping group of 19 gastric cancer patients. Eighteen had a positive response, including 10 of 11 negative for H pylori by biopsy urease testing. The systemic and local immunoblotting results show that the high seroprevalence of H pylori antibodies detected by ELISA is nevertheless an underestimate of past infection. Dyspepsia screening policies based solely on H pylori ELISA would miss some young patients with gastric cancer. Further study of the relation of the H pylori cytotoxin to gastric precancerous lesions is warranted.

Adenocarcinoma↗
PubMed1993

Revising the rules of employment liability.

Employment-at-will is an employee relations law doctrine dating back to the mid-19th century in the U.S. Learn how to handle certain employment relations issues specific to long-term care.

Contract Services↗
PubMed1993

Outpost pharmacy.

Explore the source record for details and available documents.

Australia↗
PubMed1993

An evaluation of two compact analyzers used for lipid analysis.

BACKGROUND: A number of relatively inexpensive compact analyzers are available for use in physician offices and outpatient clinics to measure total cholesterol and, more recently, high-density lipoprotein (HDL) cholesterol and triglycerides. This study was designed to document the analytical performance of two of them, the Abbott Vision and the Kodak Ektachem DT60, for assays of total cholesterol, HDL cholesterol, triglycerides, and calculated low-density lipoprotein (LDL) cholesterol. METHODS: Lipid profiles were measured from venous blood samples of 70 subjects with each test device, and results were compared with those from a laboratory standardized to the Centers for Disease Control. Coefficient of variation (CV) of multiple measurements from three pools of human serum (ie, precision), mean percent difference between device and standard laboratory results (ie, accuracy or bias), and 95% tolerance intervals (total error) were determined. The correct classification of patients into risk categories with device results was compared with the standardized laboratory results. RESULTS: The average CVs for total cholesterol, triglycerides, and HDL cholesterol with the Vision analyzer were 3.6%, 4.4%, and 10.5%, respectively, and with the DT60, 5.0%, 4.1%, and 6.8%, respectively. The average percent biases for the same analytes with the Vision analyzer were 0.2%, 4.0%, and -2.3%, respectively, and with the DT60, -2.1%, 12.1%, and 0.1%, respectively. Total error assessments indicated that total and HDL cholesterol measurements in individual patients met the guidelines of the National Cholesterol Education Program with both devices, but that triglycerides and LDL cholesterol measurements did not. Classification of subjects into risk groups based on total or LDL cholesterol gave clinically satisfactory results with either device. CONCLUSIONS: More precise measurement technology for LDL cholesterol is needed. Physicians and others who rely on compact analyzer results for diagnosis and treatment decisions should consider the degree of inaccuracy and imprecision in these values.

Adult↗
PubMed1993

Does war stress contribute to hypertension?

Veterans often apply to the Department of Veterans' Affairs to have their hypertension accepted as related to their war service. Claims may be rejected on the grounds that stress does not affect hypertension. Veterans' organisations often recommend an appeal and general practitioners may then become involved. This article was written to help the practitioner advise the veteran and explains why hypertension may be granted on appeal.

Alcoholism↗
PubMed1992

Marked variation in the size of genomic plasmids among members of a family of related Epstein-Barr viruses.

Epstein-Barr virus (EBV) genomes in the P3J-HR-1 (HR-1) Burkitt lymphoma cell line rearrange at a high rate. Previously described deletions and rearrangements in HR-1 cells have been found at sites of EBV replication in vivo, suggesting that DNA rearrangement may be an integral aspect of EBV biology and pathogenesis. We examined the structure of linear EBV genomes in subcultures of HR-1 cells using contour-clamped homogenous electric field gel electrophoresis. We developed a second pulsed electrophoretic technique to separate intracellular circular EBV plasmids. The standard, linear HR-1 EBV genome was approximately 155 kilobases in length. Linear molecules of less than unit length, presumably defective genomes, were seen in numerous subcultures. Linear intracellular genomes greater than 155 kilobases were also detected, but only linear genomes of 155 kilobases or less were packaged into virions. The size of circular EBV plasmids also varied greatly among HR-1 subcultures, some of which contained two plasmids of different size. The progeny of the unusual circular plasmids could be either standard or nonstandard linear genomes. No aberrant linear or circular form was detected in a subculture carrying the previously described het fragments. Pulsed-gel electrophoresis has provided two additional characteristics of mutant EBVs: abnormal linear and circular genome configurations.

Blotting, Southern↗
PubMed1992

Viral proteins associated with the Epstein-Barr virus transactivator, ZEBRA.

The BamHI Z Epstein-Barr replication activator (ZEBRA) mediates disruption of latency and induction of Epstein-Barr virus (EBV) early gene expression in latently infected lymphocytes. Polyclonal rabbit sera raised against ZEBRA were used to immunoprecipitate ZEBRA-associated proteins (ZAPs). ZAPs of 19, 21, 23, and 42 kDa were coimmunoprecipitated with ZEBRA from extracts of EBV-producing lymphoid cell lines. ZAPs were not recognized directly by the rabbit sera, but they were antigenic for EBV+ human sera. Immunoprecipitation of ZAPs by ZEBRA-specific antisera required the presence of ZEBRA. ZAPs were not coprecipitated with ZEBRA from mouse cells expressing only ZEBRA, from Raji (a cell line in which EBV is unable to complete lytic replication), or from cells treated with inhibitors of viral DNA synthesis. Thus, ZAPs are late EBV-encoded proteins. ZEBRA and ZAPs colocalized to a salt-insoluble nuclear fraction, and both were found extracellularly in crude preparations of virions. ZAPs might function to affect the cellular localization of ZEBRA, to alter its capacity to transactivate, or to influence its target gene specificity.

Cell Line↗
PubMed1992

Detection of Epstein-Barr virus in the brain by the polymerase chain reaction.

Epstein-Barr virus (EBV) has been implicated in a variety of central nervous system syndromes. In a few well-studied patients, EBV has been detected by viral isolation or EBV DNA has been found by Southern hybridization analysis. Using polymerase chain reaction, we evaluated brain biopsy specimens from 24 patients for the presence of EBV genomes. EBV DNA was found in brain specimens from 18 patients in whom presence of the virus in the brain was suspected clinically or on the basis of serological tests. Six patients had acquired immunodeficiency syndrome; 2 were kidney transplant recipients. Brain specimens from 4 patients with encephalitis due to other herpes group viruses and from a patient with metabolic encephalopathy were negative for EBV DNA as determined by polymerase chain reaction. The findings indicate a need to evaluate the role of EBV in diverse neurological syndromes, especially those occurring in immunodeficient hosts.

Adolescent↗
PubMed1992

A nuclear matrix attachment region organizes the Epstein-Barr viral plasmid in Raji cells into a single DNA domain.

The extrachromosomal Epstein-Barr virus (EBV) plasmid in the Burkitt lymphoma cell line, Raji, is stably associated with the nuclear matrix. This association is effected by a nuclear matrix attachment region (MAR) located in the BamHI C fragment of the viral genome; no other region of EBV DNA was found to be attached to the nuclear matrix with high affinity. The MAR was mapped to 5.2 kbp of DNA, greater than 80% of which is found on the nuclear matrix in unsynchronized cells expressing only viral latent cycle products. Thus the majority of viral plasmids in Raji cells use the same MAR. The MAR of EBV DNA contains the origin of latent viral DNA replication (oriP), the genes for the small viral RNAs (EBERs) and a 500 bp region immediately upstream of the EBER-1 gene. The clustering of the latent viral replication origin and the nearby enhancer and promoters for latent viral transcription on the nuclear matrix is likely to be crucial for regulation of the latent viral genome.

Burkitt Lymphoma↗
PubMed1992

Blockade of the LH response induced by the agonist D-Trp-6-LHRH in rats by a highly potent LH-RH antagonist SB-75.

During treatment of prostate cancer patients with luteinizing hormone-releasing hormone agonist, a transient LH and sex steroid release, which precedes the secretion blockade, may result in a flare-up of the disease, whereas the antagonists induce an immediate suppression. The administration of the modern, superactive LHRH antagonist SB-75 before or together with the agonist D-Trp-6-LHRH should prevent the "flare-up" phenomena. In order to demonstrate that the LHRH antagonist can prevent the initial stimulation of gonadotropins in response to LHRH agonists, groups of 5-7 male rats were injected s.c. with the antagonist SB-75 in doses in 100, 500, and 1,000 micrograms/rat 1 hour prior to or 1, 2, and 3 days before administration of D-Trp-6-LHRH agonist (50 micrograms/rat). Supraphysiological doses of the agonist were used in order to obtain prolonged stimulation of LH release, which was necessary to study the duration and the extent of LH release inhibition. Blood samples were taken before and 2, 6, 24, 48, and 72 hours after D-Trp-6-LHRH stimulation for measurement of LH levels. The administration of SB-75 in doses of 500 and 1,000 micrograms/rat 3 days prior to administration of the agonist significantly lowered LH response (P less than 0.01), as compared to animals injected with D-Trp-6-LHRH alone. The D-Trp-6-LHRH-stimulated LH secretion was markedly more suppressed by all 3 doses of the antagonist in rats pretreated with SB-75 2 days prior to the stimulation with the agonist. An even greater reduction in LH response could be observed in rats injected with SB-75 1 day prior to the agonist, the magnitude of LH response being decreased by 75% with 500 micrograms/rat SB-75 and by 90% with 1 mg/rat SB-75. The LH response was virtually abolished when the antagonist, SB-75 was given in doses of 500 or 1,000 micrograms/rat 1 hour prior to the D-Trp-6-LHRH injection. Under these conditions, the agonist-induced LH and testosterone secretion was completely suppressed during the whole period of the experiment. The antagonist to agonist dose ratio of 2 to 1 produced a 90% decrease in the LH response to D-Trp-6-LHRH at 2 hours and 75% at 5 hours after agonist administration. The effects of LHRH decapeptide itself (500 micrograms/rat) on LH secretion could be totally suppressed by an injection of 50 micrograms/rat of SB-75 1 hour beforehand.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗