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Biomedical subjects

J Taylor

Publications and source records attributed to J Taylor.

At least 541 records · Page 30Linked to original sources
PubMed1988

Pox viruses as eukaryotic cloning and expression vectors: future medical and veterinary vaccines.

It was proposed at the beginning of this article that the use of poxviruses as expression vectors provided a means of optimizing the conditions and prerequisites of vaccination and of elucidating a number of the associated problems. These advantages will now be summarized. Vaccinia virus recombinants carrying one or more multiple foreign genes have been shown to induce a sufficient immune response to that antigen in laboratory animals to protect against subsequent challenge by the infectious agent. In those animals tested the duration of immunity has been long-lasting with no apparent detrimental side-effects. Vaccinia virus is very stable in normal environmental situations and no cold-chain is required in the distribution network. There is no evidence for genetic instability of the vaccinia 'carrier' strain nor of loss of the inserted genetic elements. The vaccine is administered intradermally and it is proposed that one inoculation will be sufficient to induce immunity to multiple disease antigens; however, re-inoculation at a later time with the same or new antigenic determinants is not precluded. The efficiency of vaccinia virus as the vaccine strain used to eliminate the disease of smallpox with minimal side-effects is well documented. The recent studies described here on the development of vaccinia as a viral vector confer other advantages. Since the expression of the inserted genetic element is under vaccinia virus control, different levels of expression can be engineered by substituting the promoter sequence placed proximal to the insert. This leads to the possibility of high levels of expression when required for a single antigen or more modulated levels when multiple foreign antigens are expressed and 'genetic overload' could become a problem. Much work remains to be done on the body's immune response to this proposed genetic intrusion. The ability to insert large amounts of genetic information without disrupting virus replication and assembly indicates a great degree of flexibility in the genome strategy of the virus. This may indicate that the replication system can be further disrupted to eliminate or modify those sequences coding for virulence and wide host range to make the poxvirus vector as safe as possible for vaccine use. One of the reasons traditional vaccine strategy has failed for some virus groups is the degree of variability found in virus strains in nature. Influenza viruses are a good example, as are the bluetongue virus group, rotaviruses and bunyaviruses.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Mixture decomposition applied to the analysis of two-dimensional electrophoretic separation of protein samples.

Protein samples submitted for routine separation and analysis by two-dimensional electrophoretic techniques are often a mixture of proteins from different species, cell types, subcellular components, or even unknown contaminants. Varying amounts of individual components can account for many of the major effects seen in an experiment and can mask other, more subtle changes. This paper presents methods for estimating the percentages of these components in a mixture and procedures for correcting for their presence. The methods are tested by using a simple data set composed of differing amounts of two pure fractions.

Electrophoresis, Gel, Two-Dimensional↗
PubMed1988

Empty lockers.

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Humans↗
PubMed1987

Expression of cloned sequences in biopsies of human colonic tissue and in colonic carcinoma cells induced to differentiate in vitro.

A computer-based scanning and image-processing system has been developed to quantitate the relative level of expression of each of 4000 cloned complementary DNA sequences in small biopsies routinely removed from the mucosa of normal and neoplastic human large intestine. Individuals have been studied from well-defined population groups in which colonic epithelial cells have progressed to increasingly advanced stages of neoplastic transformation. Comparison of normal colonic mucosa to colonic carcinomas demonstrated alterations in expression of approximately 7% of the cloned sequences; fewer changes were found between benign colonic adenomas and either normal colonic mucosa or carcinomas. A subset of the sequences which change in expression during progression from normal mucosa, to adenoma, to carcinoma showed complementary changes when colon carcinoma cells were induced to differentiate in vitro with sodium butyrate; quantitative correlations between in vivo and in vitro results were highly significant. Comparison of normal colonic mucosa with mucosa from patients with the autosomal dominant disease familial polyposis revealed more extensive alterations in gene expression involving approximately 25% of the clones screened. Flat colonic mucosa in familial polyposis is therefore markedly aberrant and may be highly dedifferentiated, suggesting several possible mechanisms for the very high incidence of cancer that develops in this epithelium.

Adenoma↗
PubMed1987

Lymphocyte function-associated antigen 1 (LFA-1) and natural killer (NK) cell activity: LFA-1 is not necessary for all killer: target cell interactions.

A panel of five monoclonal antibodies detecting human lymphocyte function-associated antigen 1 (LFA-1) was generated and shown by competitive binding studies to react with at least four distinct epitopes on this molecule. The antibodies were then tested for their ability to inhibit the lytic activity of a variety of different human natural killer (NK) populations on a panel of four NK-susceptible target cells (K562, MOLT-4, HSB-2, and Jurkat). When heterogeneous NK populations derived from fresh peripheral blood and mixed-lymphocyte culture (MLC)-generated lines were used, these anti-LFA-1 monoclonal antibodies (MAbs) inhibited lysis of all four NK targets; this finding supports the notion that LFA-1 molecules play an important role in NK-mediated lysis. When tested on a cloned line of NK cells (NK 3.3), lysis of K562 was inhibited by these MAbs, but lysis of the other three targets was not affected. This represents an instance where a MAb specific for LFA-1 inhibits the lytic activity of NK cells against some but not all targets; thus the LFA-1 molecule cannot be considered under all circumstances to be an absolute requirement in NK-mediated lysis.

Antibodies, Monoclonal↗
PubMed1987

Detection of heritable mutations as quantitative changes in protein expression.

A computerized search for the appearance of heritable mutations (as indicated by changes in protein expression) was conducted on three sets of mice, whose sires had been either untreated, exposed to 3 gray units of gamma radiation, or treated with 150 mg/kg ethylnitrosourea. Proteins from the livers of approximately 800 mice were separated by two-dimensional electrophoresis, and abundances were measured by using image analysis techniques. Heritable mutations were detected by the appearance of new proteins or by the quantitative decrease in abundance of normally occurring proteins. Measurements of the variability of the protein abundance indicate that at least 48 proteins are consistent enough to be used in searches when mutations are expected to result in a 50% reduction in the normal amount of protein. New proteins were found in four offspring from ethylnitrosourea-treated mice, and in each case a nearby spot was found to be significantly diminished. These mutations were confirmed in subsequent generations. A computer-assisted search detected three of these mutations on the basis of the abundance decrease alone. These results indicate that two-dimensional electrophoresis can be used to detect mutations reflected as quantitative changes in protein expression, provided that the proteins to be monitored are quantitatively stable when samples from different individuals are compared.

Animals↗
PubMed1987

Enzymatic synthesis of RNA oligonucleotides.

Using SP6 RNA polymerase and various synthetic DNA oligomers as templates (12-65 b), we have obtained efficient synthesis of RNA transcripts without the need for either primer or promoter. Gel analysis of transcripts made from templates of known size demonstrated a predominant single species, together with some minor bands. For a given template the major band had the same 5'-nucleotide as predicted from the 3'-nucleotide of the template. This synthesis procedure makes it possible to efficiently and conveniently make labeled or unlabeled RNA from synthetic DNA oligonucleotides.

DNA-Directed RNA Polymerases↗
PubMed1987

In vitro and in vivo kinetics of regulated drug release from polymer matrices by oscillating magnetic fields.

The kinetics of drug release from polymer-drug matrices containing an embedded magnet was continuously monitored in vitro and in vivo. The application of an oscillating magnetic field increased the rate of drug release from the polymer matrices. Within the limits of detection the increase in release occurred immediately, remained stable for as long as the field was applied, and returned exactly to baseline upon withdrawal of the field. The increase in release was directly proportional to field amplitude. The same pattern of results were observed in vivo as in vitro, though higher strength fields were required in vivo to achieve the same effect observed in vitro.

Animals↗
PubMed1987

Does DGAVP influence memory, attention and mood in young healthy men?

The influence of an increasing dose of the vasopressin-like peptide DGAVP (desglycinamide-arginine-vasopressin) on memory was investigated in two groups of ten healthy male volunteers to provide information about the hypothesis of improvement of memory by vasopressin. At the same time we evaluated the effect of DGAVP on mood, alertness or sleepiness in a double-blind placebo-control design. The treatment group received at 9.15 a.m. intranasally a daily increasing dose from 0.1 mg at day 1 to 10.0 mg at day 5. DGAVP did not significantly affect any measure of memory or alertness. DGAVP did, however, produce a significant increase in concentration level and mood. The results of the present study provide no support for the vasopressin theory of memory improvement; rather, the results direct the attention to attention modulating effects.

Adult↗
PubMed1987

Effect of diazepam on the speed of mental rotation.

The effect of diazepam on spatial visualization was studied using a double-blind crossover design. Diazepam 10 mg (or placebo) was given orally to 12 healthy young men at bedtime, followed again by 10 mg (or placebo) the next morning. One hour after the administration of the morning dose, the subjects performed a mental rotation task. Diazepam effects were analyzed in terms of an information processing model previously constructed to account for performance of the task. Using this method, the slope and intercept parameters of a linear function relating reaction time to task condition (i.e., angular difference in orientation between two identical stimulus figures) were computed for diazepam and placebo conditions. Diazepam significantly increased the slope and intercept of the mental rotation function (P less than 0.05). These results suggest that diazepam impairs spatial visualization ability.

Adult↗
PubMed1987

Chorioamnionitis: its association with pregnancy outcome and microbial infection.

In a study of 33 cases of perinatal death, chorioamnionitis was observed in 57.6% compared with 5% of 20 control cases (p less than 0.001) and in 70.8% of cases with no morphologic cause compared with 22.2% of cases with a defined cause of death (p less than 0.01). Chorioamnionitis was significantly associated with previous gestations (p less than 0.01), prolonged rupture of the membranes (p less than 0.001), prematurity (20 to 27 weeks' gestation) (p less than 0.001), and low birth weight (less than or equal to 1000 gm) (p less than 0.001) but not with elevated maternal white blood cell count or pyrexia. Overall, in patients with chorioamnionitis, the perinatal death rate was higher (p less than 0.01); more stillbirths occurred compared with early neonatal deaths (p less than 0.05), and there was a higher incidence of deaths with no defined cause (p less than 0.01) compared with cases without chorioamnionitis. Ureaplasma urealyticum or pathogenic bacteria were isolated more frequently from villous tissue of placentas from cases with chorioamnionitis (p less than 0.01) but not Mycoplasma hominis, Chlamydia trachomatis, or viruses. Furthermore, there was a higher prevalence of both elevated fetal antibody titer to U. urealyticum (p less than 0.025) and fetal titer fourfold above maternal titers (p less than 0.05) in cases with chorioamnionitis. The antibody responses and presence of microorganisms suggest that chorioamnionitis is associated with intrauterine infection and an associated increase in perinatal morbidity and mortality.

Bacterial Infections↗
PubMed1987

Influence of radiation therapy on oral Candida albicans colonization: a quantitative assessment.

An increase in quantity of oral Candida albicans was documented in patients receiving head and neck radiation therapy during and after therapy, as assessed by an oral-rinse culturing technique. The amount of the increase was greater in denture wearers and directly related to increasing radiation dose and increasing volume of parotid gland included in the radiation portal. A significant number of patients who did not carry C. albicans prior to radiation therapy developed positive cultures by 1 month after radiation therapy. The percentage of patients receiving head and neck radiation therapy who carried C. albicans prior to radiation therapy did not differ significantly from matched dental patient controls.

Candida albicans↗
PubMed1987

Tendon transfer in partially anaesthetic hands.

Stereognosis and sensory localisation were studied in hands of patients with partial anaesthesia due to peripheral nerve injury both before and after tendon transfer to impart movement to the anaesthetic part. One patient showed a marked improvement in stereognosis and localisation, but in general little was gained in terms of improved sensation. Function was improved more in the dominant than in the non-dominant hand. Earlier tendon transfer in cases of peripheral nerve injury might decrease cortical exclusion.

Adult↗
PubMed1987

Old and new techniques together resolve a problem of infection by Salmonella typhimurium.

Isolates of Salmonella typhimurium, recovered over a 9-month period from a child with gastroenteritis, were characterized by biotyping, phage-typing and plasmid-profile analysis. Because the data from the different methods were discrepant, it was difficult to establish whether her infection was due to a single strain that had changed character in vivo or was due to recurrent infections with different, unrelated strains. Restriction-enzyme fingerprinting of the plasmids from the different isolates provided an explanation for the initial discrepancy and high-lighted a source of potential confusion in epidemiological studies.

Bacteriophage Typing↗
PubMed1987

Now and then.

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Biology↗