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Biomedical subjects

R H Smith

Publications and source records attributed to R H Smith.

At least 19 recordsLinked to original sources
PubMed1992

Characterization of the regulatory functions of the equine herpesvirus 1 immediate-early gene product.

Use of the translation-inhibiting drug cycloheximide has indicated that the equine herpesvirus 1 (EHV-1) immediate-early (IE) gene, the sole EHV-1 IE gene, encodes a major viral regulatory protein since IE mRNA translation is a prerequisite for all further viral gene expression (W.L. Gray, R. P. Baumann, A. T. Robertson, G. B. Caughman, D. J. O'Callaghan, and J. Staczek, Virology 158:79-87, 1987). An EHV-1 IE gene expression vector (pSVIE) in combination with chimeric EHV-1 promoter-chloramphenicol acetyltransferase (CAT) reporter constructs was used in transient transfection assays to characterize the regulatory functions of the IE gene product. These experiments demonstrated that (i) the EHV-1 IE gene product is a bifunctional protein capable of both positive and negative modulation of gene expression; (ii) the IE gene product possesses an autoregulatory function which represses the IE promoter; (iii) IE autoregulation is dependent on IE promoter sequences mapping within positions -288 to +73 relative to the transcription initiation site (+1) of the IE gene; (iv) the IE gene product can independently activate the EHV-1 tk promoter (an early promoter) by as much as 60-fold; (v) two EHV-1 beta-gamma (leaky late) promoters, those of IR5 (gene 5 in the inverted repeat) and the glycoprotein D gene, demonstrate a requirement for both the IE gene product as well as a gene product encoded within the EHV-1 XbaI G fragment for significant activation; and (vi) the IE gene product is capable of activating heterologous viral promoters.

Animals↗
PubMed1991

Synthesis and characterization of a Pertussis toxin-biotin conjugate.

We prepared a Pertussis toxin-biotin conjugate and found its biological properties to be similar to those of native Pertussis toxin with respect to the hemagglutination, Chinese hamster ovary cell, and lymphocyte proliferation assays. Direct binding to Chinese hamster ovary and Jurkat cells was observed using fluorescence microscopy. Pertussis toxin-biotin was also found to possess similar glycoconjugate binding specificities as those of 125I-labeled Pertussis toxin.

Animals↗
PubMed1991

A mechanism for maintaining an up-to-date GenBank database via Usenet.

In this paper, we describe an automated system for distributing updates to the GenBank nucleic acid sequence database, using the Usenet news system as the underlying transport mechanism. Our system allows new loci to be distributed as soon as the sequences are available, over existing networks, using existing Usenet software and infrastructure currently available on a wide range of computer systems.

Amino Acid Sequence↗
PubMed1991

Measurement of phenytoin and carbamazepine in an ultrafiltrate of saliva.

We have introduced a method of collecting a prepurified sample of saliva in the mouth for the quantitative determination of phenytoin and carbamazepine. The patient places in the mouth an osmotic device that accumulates in greater than 8 min a volume of approximately 1.2 ml clear ultrafiltrate devoid of molecules greater than 12,000 daltons. The concentrations of phenytoin and carbamazepine in serum (total and free fractions), whole saliva, and the salivary ultrafiltrate from patients receiving anticonvulsant treatment were measured and correlated. The correlation coefficients r (p less than 0.001) for phenytoin were: total in serum and ultrafiltrate r = 0.92; free in serum and ultrafiltrate r = 0.93; whole saliva and ultrafiltrate r = 0.95. The correlation coefficients for carbamazepine were (in the same order) 0.90, 0.92, and 0.93. It is concluded that the use of an ultrafiltrate as a biological medium simplifies the diagnostic evaluation of free circulating phenytoin and carbamazepine concentrations for monitoring therapy.

Adolescent↗
PubMed1991

A simple larval diet for population studies on the blowfly Lucilia sericata (Diptera: Calliphoridae).

1. A simple artificial diet was devised for larvae of Lucilia sericata Meigen. 2. A basic diet of 20 g/l agar with 20% horse blood and added yeast sustained normal growth and development, as compared with a lamb meat control. 3. When yeast was added to the blood agar diet at 50 g/l, both peak and final larval weights were increased by 25-50% at higher larval densities (2-8 larvae/g diet) and the hatchling-adult development period was reduced by about 3 days. 4. No adult insects emerged on an agar-yeast diet without blood. Increasing the concentration of blood from 10% to 20% increased adult weight at emergence by 50%, though developmental period was not significantly affected. 5. Increasing larval density significantly reduced the weights of pupae and emergent adults (by up to 50%), both on the blood-agar-yeast diet and the lamb meat control. Percentage survival fell from 80-90% to below 10% on the blood-agar-yeast diet at the highest densities of 4 or 8 larvae/g diet, though survival on lamb was not significantly affected by density.

Analysis of Variance↗
PubMed1991

Predictors of alcohol abuse behaviors of undergraduates.

A representative sample of 713 Mary Washington College undergraduates responded to questions about alcohol effects, their own alcohol use, and their beliefs about the risks associated with alcohol use for college students in general and for themselves in particular. Item correlations suggested four indexes: personal risk of abuse, personal risk of alcohol-related misfortune, alcohol consumption, and alcohol abuse. Knowledge did not predict reduced use or abuse patterns, nor did perceived risk of abuse for students in general. Abuse, consumption and personal risk of abuse were all positively intercorrelated. However, personal risk of alcohol-related misfortune was negatively correlated with all other indexes. These findings have important implications for programs to reduce alcohol abuse among young people.

Adult↗
PubMed1991

The Air Force Nurse Intern Program.

The Air Force Nurse Intern Program is a 5-month-long introduction to Air Force nursing for BSN-prepared graduate nurses. The program is designed to facilitate the transition from civilian nursing student to practicing Air Force Nurse Corps Officer. After attending Military Indoctrination for Medical Service Officers, newly commissioned nurses attend the program at one of 10 Air Force medical centers before going to their permanent duty stations. Preceptors guide and instruct the interns at each of four clinical rotation sites. The author, a former nurse intern, describes some of the many opportunities available to nurse interns.

Internship and Residency↗
PubMed1990

1,3-Dialkyl-3-acyltriazenes, a novel class of antineoplastic alkylating agents.

Aliphatic triazenes, such as 1,3-dimethyltriazene, are potent biological alkylating agents because they form alkyldiazonium ions. They are also subject to very rapid proteolytic decomposition, even at physiological pH. The acylated analogues 1,3-dialkyl-3-acyltrizenes are much more stable in aqueous solution, but they also give rise to alkyldiazonium ions. Four acylated 1,3-dimethyltriazenes, where the acyl groups were diethylphosphoryl (DMP), carbethoxy (DMC), acetyl (DMA), and N-methylcarbamoyl (DMM), were studied kinetically. Rate-pH profiles indicated that the acyl group had a profound effect on the mechanism of decomposition. The cytotoxic potential of all four compounds was studied in vitro by using the MTT-tetrazolium assay. The compounds had fair-to-good activity against some cell lines, particularly those deficient in methylation repair. In vivo assays of DMC and DMM against several tumor xenografts in nude mice showed promising activity for some cancers, particularly in the case of DMM. In vitro assays were also carried out on three 1-(2-chloroethyl)-3-methyl-3-acyltriazenes. The acyl groups were carbethoxy (CMC), acetyl (CMA), and N-methylcarbamoyl (CMM). The activity of these compounds largely paralleled that of bis(2-chloroethyl)-N-nitrosourea (BCNU), except for those cell lines which exhibited the Rem phenotype; triazenes were more active in those lines than BCNU. The in vivo activity of CMC, CMA, and CMM was tested in the P388 leukemia assay. All three were active but CMC and CMA proved to be rather toxic. CMM was well tolerated and was examined in several tumor xenografts in nude mice. Significant activity was found against MX-1 mammary carcinoma, against LX-1 small cell lung carcinoma, and particularly against LOX amelanotic melanoma, where complete cures were effected. The antineoplastic activity of the acyltriazenes is well-correlated with their chemical behavior.

Alkylating Agents↗
PubMed1990

Rapid solid-phase immunoassay for 6-keto prostaglandin F1 alpha on microplates.

We describe, for the measurement of 6-keto prostaglandin F1 alpha in biological media, a solid-phase immunoassay with immobilized antibodies that requires a total processing time of less than 2 h with hands-on time less than 30 min for 40 samples. The method combines the convenience of the microplate format with the sensitivity of radiolabeled prostaglandin derivatives as tracers in a competitive immunoassay. The intra- and interassay variations at 50% displacement of the radiolabeled prostaglandin derivative as tracer were 9.0% and 11.8%, respectively. At 50% displacement of the radiolabeled tracer, the sensitivity is about 20 pg per well. Optimal incubation time is between 60 and 90 min. Nonspecific binding was less than 1% if about 8 pg of tracer (approximately 25,000 counts/min per well) was used. Inhibition curves of samples in different dilutions were parallel to standard curves. The variation of bound radiolabeled prostaglandin derivative within the wells of one microplate (n = 96) was less than 3%. Human plasma samples and medium from tissue culture assayed for 6-keto prostaglandin F1 alpha correlated well with results obtained with a solid-phase assay based on use of magnetic particles (r = 0.99, n = 24 for culture-medium samples; r = 0.99; n = 26 for plasma samples.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Determination of free progesterone in an ultrafiltrate of saliva collected in situ.

We have investigated the utility of an ultrafiltrate of saliva for measuring progesterone as an indicator of luteal function during the menstrual cycle of women. A filtrate of saliva is collected in the mouth by means of an osmotic pump that accumulates medium containing only molecules less than 12,000 Da. We analyzed the nonextracted ultrafiltrate by a solid-phase immunoassay for progesterone and monitored the mid-luteal surge of lutropin in urine with a liquid-phase radioimmunoassay. Progesterone concentrations in the ultrafiltrate are significantly lower during the follicular phase and increase after the release of lutropin. The concentration of progesterone in the ultrafiltrate correlates closely with total progesterone in matched blood samples (r = 0.84, cycle 1; and r = 0.89, cycle 2). Likewise, we found a good correlation between the results in whole saliva and in the ultrafiltrate (r = 0.95). The described method of obtaining a pre-processed specimen noninvasively simplifies the self-collection of samples by patients (including collection at home); excludes potential interference from microorganisms, desquamated cells, and salivary components; and simplifies the processing of the biological fluid in the laboratory.

Adult↗
PubMed1989

Intrapersonal and social comparison determinants of happiness: a range-frequency analysis.

Examined whether intrapersonal comparisons and social comparisons operate in similar ways to determine ratings of happiness. Events were varied to create positively and negatively skewed distributions. The events in each distribution were ascribed to either a single person or a group of people; Ss rated how happy they would feel if they experienced specific events within the distribution. Ratings for both intrapersonal and social comparisons were fit well by Parducci's (1984) range-frequency theory. Individual events received higher ratings when presented within the positively skewed context. Overall happiness, as measured by both the mean of the happiness ratings as well as direct ratings, was highest for the negatively skewed distributions. The effects of skewing were more pronounced for intrapersonal comparisons, but ratings were more closely defined by the range of experimental stimuli for social comparisons.

Adult↗
PubMed1989

T-cell recognition of measles virus haemagglutinin studied in a mouse model.

BALB/c mice were pretreated with cyclophosphamide and immunized 2 days later with inactivated, purified measles virus (MV) mixed with dimethyl dioctadecyl ammonium bromide (DDA). Seven days later, lymph nodes (LN) were removed and lymphocytes cultured in the presence of purified MV antigens. MV haemagglutinin (H) was found to be a major antigen responsible for proliferation of the lymphocytes. Incorporation of purified H into liposomes significantly enhanced the proliferative response compared with purified H alone. Response to MV nucleocapsid protein was only moderate, and insertion of this protein into liposomes did not improve the response. As an attempt to analyse T-cell epitopes of MV H, three synthetic peptides previously found to elicit a strong antibody response were used both as priming and stimulating antigens. None of the peptides was able to elicit a secondary response when MV-primed LN cells were stimulated in vitro. However, each peptide primed T cells for a secondary challenge with purified, inactivated MV, which was demonstrated by proliferation and a delayed-type hypersensitivity assay and also by transfer experiments with peptide-primed cells.

Amino Acid Sequence↗
PubMed1989

Opines stimulate induction of the vir genes of the Agrobacterium tumefaciens Ti plasmid.

Upon incubation of Agrobacterium tumefaciens A348 with acetosyringone, the vir genes encoded by the Ti (tumor-inducing) plasmid are induced. The addition of certain opines, including octopine, nopaline, leucinopine, and succinamopine, enhanced this induction 2- to 10-fold. The compounds mannopine, acetopine, arginine, pyruvate, and leucine did not stimulate the induction of the vir genes to such an extent. The enhancement of vir gene induction by opines depended on acetosyringone and the genes virA and virG. Opines stimulated the activity of the vir genes, the double-stranded cleavage of the T (transferred)-DNA at the border repeat sequences, and the production of T-strands by the bacterium. The transformation efficiency of cotton shoot tips was markedly increased by the addition of acetosyringone and nopaline at the time of infection.

Acetophenones↗