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Biomedical subjects

J Taylor

Publications and source records attributed to J Taylor.

At least 505 records · Page 28Linked to original sources
PubMed1989

Detection of reassortant orbiviruses (Wallal serogroup) in a prototype strain isolated from a pool of biting midges (Culicoides dycei).

Genetic variation between clones selected from early passage pools of Wallal virus (Reoviridae, Orbivirus) was investigated. The virus had been isolated in 1970 from a pool of 100 insects (Culicoides dycei), caught in the wild, by laboratory passage in suckling mice. Gel electrophoresis and oligonucleotide fingerprint analysis of clones indicated that multiple reassortant genotypes were present in early passages of the original isolate. The virus, previously described as the prototype strain of Wallal virus, was one of the reassortant clones. A virus recovered during reisolation from the same insect pool was genotypically and serologically distinct from the prototype strain and represents a second Wallal serotype. We have concluded that the clonal variation was due to the presence of two orbivirus serotypes in the original insect pool and that a range of reassortant viruses were generated during early passages of the material in mice.

Animals↗
PubMed1989

Developmental changes in the calcium dependency of gamma-aminobutyric acid release from isolated growth cones: correlation with growth cone morphology.

We have investigated the development of Ca2+-dependent gamma-[3H]aminobutyric acid [( 3H]GABA) release in superfused growth cone fractions isolated from rats between the postnatal ages of 1 and 11 days. We have compared this release with the overall morphology of the subcellular fractions, and identified those structures taking up [3H]GABA by electron microscopical autoradiography. In fractions isolated from rats between 1 and 5 days, K+-evoked [3H]GABA release was completely independent of extracellular Ca2+. After 5 days a Ca2+ dependency appeared, which increased with age, such that by 10 days approximately 50% of the K+-evoked release was Ca2+ dependent. Electron microscopical analysis showed that, at all ages, large numbers of GABAergic growth cones were present in the subcellular fractions. Up to postnatal day 5, the growth cones were synaptic vesicle sparse but, after this age, increasing numbers of synaptic vesicle-containing growth cones were seen. These results suggest that during maturation of GABAergic growth cones into synapses there is, initially, a mechanism for release that is independent of extracellular Ca2+ and that the appearance of a Ca2+-dependent [3H]GABA release from growth cones correlates with the appearance of synaptic vesicles.

Aging↗
PubMed1989

A preliminary study of social issues in AIDS prevention among adolescents.

Educational efforts to prevent the spread of AIDS require a combination of accurate information and the application of that information to personal behavior. In this preliminary study, a scale was developed to evaluate the social and interpersonal skills of adolescents in AIDS-related and non-AIDS-related interactions. The instrument was administered to 101 Australian students in grades 10 and 11 of an urban high school. Findings indicate ratings of AIDS-related activities of the adolescents were not significantly different from their other social activities, suggesting levels of comfort and assertiveness among adolescents in AIDS-related activities can be modified. Students felt most anxious about problems with sexually transmitted diseases or drug use, suggesting difficulty in dealing with the possible public disclosure of these stigmatized conditions. Data suggest both individual and group scores among adolescents may improve on the five dimensions of the scale following interventions to promote social and interpersonal skills designed to apply knowledge obtained from AIDS education.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Loss of a rural hospital obstetric unit: a case study.

As family and general practitioners who provide a substantial portion of the obstetric care in rural areas quit their obstetric practice, small rural hospital obstetric units are at risk of closing. Using a case study design, we examined the impact of the loss of obstetric services at a small rural hospital in Missouri. This unit was the site of delivery for less than one-half of the infants born to women living within its service area. However, it was the most likely source of care for women who were young, undereducated and unmarried (p less than 0.01). Evidence derived from birth certificates showed that women who delivered there had good perinatal outcomes compared with local women who delivered at larger hospitals. A gradual decline in the number of physicians providing obstetric care preceded the closing of the hospital unit. Women from the hospital service area who presented late for prenatal care were twice as likely to have had a low birthweight infant in the year after the local hospital unit closed (16.7% versus 7.4%), although this difference and other comparisons of outcomes were not statistically significant.

Evaluation Studies as Topic↗
PubMed1989

Cloned hepatitis delta virus cDNA is infectious in the chimpanzee.

A head-to-tail trimer of a full-length cDNA clone of the hepatitis delta virus (HDV) genome was examined for infectivity by direct inoculation into the liver of a chimpanzee that was already infected with hepatitis B virus. Five weeks after inoculation, a marked elevation of serum alanine aminotransferase activity was observed, followed by the appearance of high levels of HDV RNA and antigen in both liver and serum and a high level of viral particles in the serum. A transient suppression of hepatitis B virus replication was evident during the acute phase of HDV infection. Seroconversion for antibodies to delta antigen occurred 3 weeks after the onset of the disease. These results demonstrate that a typical HDV infection can be initiated by inoculation of a susceptible animal with recombinant HDV cDNA.

Animals↗
PubMed1989

Self-ligating RNA sequences on the antigenome of human hepatitis delta virus.

A 179-base fragment of RNA from the 1,679-base antigenome of hepatitis delta virus can not only self-cleave but, when the ends of the resultant fragments are brought into apposition by base pairing to another RNA, also self-ligate. Thus, processing events needed for genome replication in vivo may be strictly RNA mediated.

Hepatitis Delta Virus↗
PubMed1989

Initiation of replication of the human hepatitis delta virus genome from cloned DNA: role of delta antigen.

Beginning with three partial cDNA clones of the RNA genome of human hepatitis delta virus (HDV), we assembled the complete 1,679-base sequence on a single molecule and then inserted a trimer of this into plasmid pSLV, a simian virus 40-based eucaryotic expression vector. This construct was used to transfect both monkey kidney (COS7) and human hepatocellular carcinoma (HuH7) cell lines. In this way we obtained replication of the HDV RNA genome and the appearance, in the nucleoli, of the delta antigen, the only known virus-coded protein. This proved both that the HDV genome could replicate in nonliver as well as liver cells and that there was no requirement for the presence of hepatitis B virus sequences or proteins. When the pSVL construct was made with a dimer of an HDV sequence with a 2-base-pair deletion in the open reading frame, genome replication was reduced at least 40-fold. However, when we cotransfected with a plasmid that expressed the correct delta antigen, the mutated dimer achieved a level of genome replication comparable to that of the nonmutated sequence. We thus conclude that the delta antigen can act in trans and is essential for replication of the HDV genome.

Antigens, Viral↗
PubMed1989

Heparin lock intravenous line. Use in newborn infants. A controlled trial.

The heparin lock technique has been available for parenteral access in older children and adults but has not yet been described for use in newborns. We randomized 39 newborns who needed parenteral medication in the intermediate care nursery to receive a heparin lock catheter (17) or an intravenous line kept patent by continuous low infusion rate (22). There were no differences between study groups with regard to birthweight, gestational age, or distribution of diagnoses. Infants in the heparin lock group were enrolled in the study on average 1 day longer than the continuous intravenous group (p less than 0.05). Subcutaneous infiltration occurred twice as frequently with the continuous intravenous line (p = 0.0015), and the life span was significantly less than heparin lock (1.0 +/- 0.5 days versus 2.1 +/- 1.0 days, p = 0.0003). Infants with continuous intravenous lines received approximately 20 ml/kg/day greater quantity of fluid (p less than 0.0001). There was no difference between groups with regard to mean heparin activity level. None of the infants developed hemorrhagic complications, thrombophlebitis, or documented nosocomial infection. Nurses significantly favored heparin locks over continuous intravenous lines for ease of use. The heparin lock technique is a safe and reasonable alternative to a continuous low infusion intravenous line for administering parenteral medications to intermediate care newborns.

Catheters, Indwelling↗
PubMed1989

Acetylsalicylic acid dose fails to affect energy intake of osteoarthritic elderly.

The objective of the study was to determine the effect on energy intake and appetite of acetylsalicylic acid (ASA), commonly used by the elderly to treat arthritis. In a double blind cross-over study, 23 free-living osteoarthritic patients 60 years of age or older were treated for two-weeks intervals with a mean daily ASA intake of 2.44 and 1.29 grams, respectively. Twenty healthy persons similar in age, taking no medication, and matched in sociocultural characteristics were included as a control group. Appetite was measured directly, using a visual analogue scale, and indirectly by calculating energy intake from three-day food records. Varying the dose of ASA was without effect on appetite and food energy intake; however, as appetite was rated lower by the medicated osteoarthritic than by the healthy group, although the energy intakes were not significantly different, the former should be considered as potentially at nutritional risk.

Aged↗
PubMed1989

Circumstances of sexual and physical victimization of black psychiatric outpatients.

A sample of 54 adult psychiatric outpatients, previously identified as victims of sexual or physical assault, were interviewed regarding their childhood and adult victimization experiences. Patients were questioned about the nature of the assaults, their relationship to the perpetrator(s), the number of assaults suffered in each relationship, and whether the assault(s) occurred before or after the onset of their mental illness. Eighty percent of the sample had experienced major physical assault as an adult and 59% had experienced major physical assault as a child; 37% and 31%, respectively, reported major sexual assault as a child and as an adult. Women were more likely than men to report physical and sexual assault as an adult and sexual assault as a child. Childhood assault most often occurred before the onset of the patient's mental illness; whereas, adult sexual assault for women and physical and sexual assault for men was as likely to occur after the onset of the psychiatric disorder, suggesting an increased vulnerability to victimization for the adult mentally ill.

Adult↗
PubMed1988

A comparison of bovine growth-hormone gene expression in mouse L cells directed by the Moloney murine-leukemia virus long terminal repeat, simian virus-40 early promoter or cytomegalovirus immediate-early promoter.

Three transcriptional regulatory regions including a human cytomegalovirus immediate-early region (CMVIE) promoter, the simian virus-40 early region (SV40E) promoter, and Moloney murine leukemia virus (MoMLV) long terminal repeat (LTR) were ligated to the bovine growth hormone (bGH)-coding gene. Using a bGH transient expression system, the CMVIE and SV40E gene transcriptional regulatory regions were found to be approximately two-fold more efficient than the MoMLV LTR in directing expression of bGH in mouse L cells.

Animals↗
PubMed1988

Probing peptide backbone function in bombesin. A reduced peptide bond analogue with potent and specific receptor antagonist activity.

Each peptide bond CONH group in the most important COOH-terminal octapeptide region of [Leu14]bombesin was replaced by a CH2NH group using recently developed rapid solid-phase methods. The resulting analogues were then examined for amylase releasing activity in guinea pig pancreatic acini and for their ability to inhibit binding of [125I-Tyr4]bombesin to acinar cells. Replacement of the Trp8-Ala9, Gly11-His12, and His12-Leu13 peptide bonds resulted in about 1000-, 200-, and 300-fold losses in both amylase releasing activity and binding affinity. The Val10-Gly11 replacement, however, retained 30% potency relative to the parent peptide. Ala9-Val10 and Leu13-Leu14 bond replacement analogues exhibited no detectable amylase releasing activity but were still able to bind to acini with Kd values of 1060 and 60 nM, respectively (compared to 15 nM for [Leu14]bombesin itself). Subsequently, both analogues were demonstrated to be competitive inhibitors of bombesin-stimulated amylase release with IC50 values of 937 and 35 nM, respectively. [Leu14-psi-CH2NH-Leu13]Bombesin exhibits a 100-fold improvement in binding affinity compared to previously reported bombesin receptor antagonists and showed no affinity for substance P receptors. It was also a potent inhibitor of bombesin-stimulated growth of murine Swiss 3T3 cells with an IC50 of 18 nM. In terms of a bombesin receptor-binding conformation, these results may aid in the delineation of intramolecular hydrogen-bonding points and the eventual design of improved, conformationally restricted analogues.

Amylases↗