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Biomedical subjects

M Wilson

Publications and source records attributed to M Wilson.

At least 541 records · Page 30Linked to original sources
PubMed1990

Adenosine-uridine binding factor requires metals for binding to granulocyte-macrophage colony-stimulating factor mRNA.

Post-transcriptional gene regulation plays an important role in the expression of granulocyte-macrophage colony-stimulating factor (GM-CSF). Cytokine secretion by activated lymphocytes or mast cells is preceded by dramatic stabilization of the normally labile GM-CSF mRNA. The 3'-untranslated region of GM-CSF and other labile mRNAs contain the destabilizing motif adenosine-uridine-uridine-uridine-adenosine (AUUUA). We recently identified a cytoplasmic protein denoted the adenosine-uridine binding factor (AUBF) which binds with high affinity and specificity to AUUUA elements in synthetic RNA transcripts. We now demonstrate that AUBF binds specifically to GM-CSF mRNA through the destabilizing AUUUA elements. The formation of AUBF-GM-CSF RNA complexes required calcium or magnesium which were sensitive to EDTA or EGTA. A variety of other divalent metals blocked magnesium-dependent AUBF activity. These observations suggest that AUBF may protect GM-CSF mRNA from rapid degradation and play a crucial role in the expression of cytokine genes.

Animals↗
PubMed1990

Susceptibility and resistance of plaque bacteria to minocycline.

The in vitro susceptibility of 55 strains of subgingival plaque bacteria to minocycline was determined. A concentration of 1 microgram/ml minocycline was found to inhibit 85% of the strains tested and the MIC ranged from 0.03 to 32 micrograms/ml. For 71% of the strains tested the MBC was at least 4 times greater than the corresponding MIC, suggesting a bacteriostatic activity for minocycline. A concentration of 20 mg/ml of magnesium ions was capable of neutralizing 8 micrograms/ml of minocycline and was used to eliminate "carry-over" effects inherent in the experimental procedure. After 6 to 7 weeks exposure to sub-lethal concentrations of minocycline there was no appreciable increase in the MICs of most organisms with the exception of Actinobacillus actinomycetemcomitans NCTC 10981 and Campylobacter concisus NCTC 11485. Short term (6 hour exposure of bacteria to minocycline (8 micrograms/ml) markedly reduced the viability of a number of periodontopathogens but had little effect on the viability of Veillonella parvula NCTC 11456 and Fusobacterium nucleatum NCTC 11326. These in vitro investigations have demonstrated that minocycline is capable of inhibiting most of the periodontitis-associated bacteria tested and can kill some of these bacteria after a comparatively short exposure time. However, some of the organisms tested exhibited a low susceptibility to minocycline and others became less susceptible following exposure to low concentrations of the antibiotic for several weeks.

Bacteria↗
PubMed1990

Susceptibility of oral bacteria to phenoxyethanol and phenoxyethanol/chlorhexidine combinations.

A total of 57 bacterial strains (26 different species) which may be isolated from subgingival plaque were tested for their in vitro susceptibility to phenoxycthanol, a commonly-used antiseptic and preservative. Ninety-five percent of the strains, including those associated with chronic inflammatory periodontal disease, were susceptible to concentrations of phenoxyethanol used topically (2% w/v). Phenoxyethanol at a concentration of 1% (w/v) was also found that to have a rapid bactericidal effect achieving a 99.9% kill in 5 minutes or less for species such as Bacterodides gingivalis, Fusobacterium nucleatum, Eikenella corrodens, and Wolinella recta. Addition of chlorhexidine to phenoxyethanol resulted in a mixture with increased antibacterial activity. For most bacterial strains, the presence of chlorhexidine resulted in at least a four-fold decrease in the concentration of pheoxyethanol required for inhibition of growth. These results imply that phenoxyethanol may be useful in the treatment of chronic inflammatory periodontal disease either by itself or in combination with chlorhexidine.

Actinobacillus↗
PubMed1990

Sensitivity of oral bacteria to imipenem and other antibiotics.

Specimens from a variety of oral and maxillofacial infections were cultured and 88 bacterial isolates belonging to the genera Bacteroides, Actinomyces, Staphylococcus, Veillonella, Eubacterium, Streptococcus and Aerococcus were obtained. These were tested for their sensitivity to imipenem, penicillin, cefuroxime, vancomycin, erythromycin and fusidic acid. Imipenem proved to be the most effective of the antibiotics tested, inhibiting all 88 isolates. Penicillin was the least effective in that it inhibited only 56% of the isolates.

Anti-Bacterial Agents↗
PubMed1990

[Microbiological study of urethritis in men].

From 1985 to 1987 we obtained urethral samples from 453 patients with a clinical diagnosis of urethritis. N gonorrhoeae was isolated in 55%, a rate that increased along the study period. The most common other agent was U urealyticum alone or in combination with other organisms. Among 82 patients, the incidence of chlamydia trachomatis was 19%. The proportion of Beta-lactamase producing strains among N gonorrhoeae varied form 7% in 1985 to 13% in 87 and 3% in 1988.

Adolescent↗
PubMed1989

Development of synapses between chick retinal neurons in dispersed culture.

Morphological criteria allow several kinds of synapse to be recognized in the vertebrate retina. It is, however, not presently known if, or how, these morphological differences reflect physiological distinctions. Since a proper investigation of synaptic physiology in the intact retina is compromised by technical difficulties, we have examined dispersed cultures to discover if they are likely to provide a more tractable physiological preparation. The chief question addressed here concerns the extent to which normal synaptic development takes place in the impoverished conditions of dispersed cell culture. Cultures were established from embryonic day 8 chick retina and fixed for microscopy on embryonic equivalent (E.E.) days 12, 14, 16, and 18. Neuronal processes appeared shortly after plating and continued to increase in number and extent through E.E. 16. Cone cells were recognizable by virtue of their distinctive oil droplets. Two classes of cone could be distinguished on the basis of the density of their cytoplasmic staining. Presynaptic ribbons could be observed in cone cells on E.E. 12, but characteristic dyad and triad postsynaptic organization was seldom present at this stage nor was it often observed at subsequent times. An increase in the number of ribbon synapses in culture was seen on E.E. 18. These synapses may represent those of bipolar cells. Conventional synapses were found at all times examined but the number of these increased greatly between E.E. 14 and 16. Of these conventional synapses, we found some whose anatomy was characteristic of synapses made by amacrine cells as well as some whose anatomy was characteristic of synapses made by bipolar cells.

Animals↗
PubMed1989

Duplication of 5q11.2----q13.1 from a familial (5;20) balanced insertion.

A 2-year-old boy with gross motor delay and few minor anomalies has a pure duplication of a small segment of chromosome 5q11.2----q13.1. A balanced insertion of this 5q segment into chromosome 20q proximal to the centromere has been found in his father, uncle, and paternal grandmother.

Abnormalities, Multiple↗
PubMed1989

Whole body and regional retention of Tc-99m-labeled diphosphonates with a whole-body counter: a study with normal males.

A collimated whole-body counter was used to measure the retention and distribution of radioactivity along the longitudinal axis of the body at several times during the 24 hours after the intravenous injection of 50 microCi of Tc-99m-diphosphonates. Whole-body retention (WBR) was measured together with regional uptakes in the following four areas: head, chest, bladder, and legs using two structurally related Tc-99m-diphosphonate skeletal imaging agents: 1-hydroxyethylidene diphosphonate (HEDP) and methylene diphosphonate (MDP). The average 24 hour WBR values in young males, reflecting skeletal uptake of these tracers, were 17.7 +/- 2.2% (n = 20) and 31.0 +/- 2.4% (n = 3), respectively. A model of skeletal clearance was developed using the sum of two exponentials. In normal volunteers the initial rapid clearance phase of both tracers had a half-time of about 1 hour, whereas the slower second phase clearance had a half-time of 22 hours with HEDP and 44 hours with MDP. The WBR is usually calculated for the entire body only at 24 hours, but with the improved spatial resolution of a collimated whole-body counter, regional measurements could potentially be done over shorter periods (6-8 hours) in order to simplify the procedure.

Bone Diseases↗
PubMed1989

Use of sodium dichloroisocyanurate granules for spills of body fluids.

The use of chlorine-containing granules for disinfecting body fluid spills has been evaluated by hospital trials and laboratory tests. Hospital trials were carried out by nurses using 'Presept' disinfectant granules according to a protocol. In general they preferred using granules to bleach and, in 50 tests using granules on natural and artificial spills in wards, no organisms were recovered from the floor by contact plates after using the granules. Laboratory tests were carried out on 'Haz-Tab' granules, 'Biospot' disinfectant powder, 'Presept' disinfectant granules, 'Virusorb' absorbent powder and 'Titan' Sanitizer SU 357 using a standardized surface test. Available chlorine levels varied from 57.8% to 1.0% and the performance of products in the surface test varied with the chlorine level present. Granules containing a relatively high level of chlorine have the advantages that spilled material is contained and that a contact time of only 2-3 min is required before the spill can be safely removed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Prevention of bacterial adhesion to denture acrylic.

A range of non-toxic polysaccharides were screened for their ability to prevent bacterial adhesion to denture acrylic in vitro. Sodium alginate, karaya gum and carrageenan were found to be the most effective, reducing adhesion of Streptococcus salivarius by 98.7, 97.9 and 99.2 per cent respectively. These three polysaccharides were then tested for their ability to reduce the number of bacteria adhering to dentures in vivo. Sodium alginate was the most effective, reducing the attachment of bacteria to the palate-contacting surface of the denture after 5 h of normal wear by 84 per cent compared with uncoated controls. The results of this investigation suggest that the accumulation of denture plaque may be prevented by frequent application of a renewable, sacrificial coating of a non-toxic polysaccharide.

Acrylic Resins↗
PubMed1989

The in-vitro effect of an amine fluoride gel on subgingival plaque bacteria.

Subgingival plaque samples obtained from 25 patients with chronic inflammatory periodontal disease were exposed in vitro to a commercial dental gel formulation containing two amine fluorides. High dilutions (1 in 32) of the gel inhibited the growth of all cultivable bacteria in all of the samples. Lower concentrations of gel were still effective, with a 1 in 128 dilution of the gel, corresponding to an amine fluoride concentration of 260 mg/l, inhibiting 97.5% of the bacteria in the samples.

Amines↗
PubMed1989

Comparison of trauma assessment scores and their use in prediction of infection and death.

Current trauma assessment scores do not include an assessment of immune competence and have not been designed to predict late death from or risk of infection. We have compared the use of the Outcome Predictive Score (OPS) with other standard scales to predict clinical outcome after trauma. The OPS combines the Injury Severity Score (ISS) corrected for age (%LD50), degree of bacterial contamination, and monocyte HLA-DR antigen expression on hospital admission. The OPS was compared to the ISS, %LD50, Revised Trauma Score (RTS), Combined Trauma Score-ISS (TRISS), and Anatomical Index (AI). Sixty-one seriously ill patients were studied. Patient outcome was defined as uneventful recovery (n = 18), major infection (n = 27), and death (13 of 16 deaths resulted from infection). The assessment scores were compared for their use in prediction of these outcomes, as well as their ability to distinguish patients with good outcome from those patients who developed major infection or died, and to differentiate survival from death. Only the OPS was able to significantly segregate all five outcome groups (p less than 0.05). Although the age-adjusted ISS distinguished between survival and death (p less than 0.05), only OPS consistently distinguished between good outcome and sepsis/death (p less than 0.05), and therefore best identified the patients who developed infection. AI, RTS, and TRISS had little predictive value.

Age Factors↗
PubMed1989

The in vitro effects of chlorhexidine on subgingival plaque bacteria.

The purpose of this study was to determine the susceptibility to chlorhexidine of a range of bacteria which may be isolated from subgingival plaque. In addition, the effect of chlorhexidine on the survival of bacteria in subgingival plaque samples from patients with chronic inflammatory periodontal disease was investigated. The minimum inhibitory concentration (MIC) of chlorhexidine for 52 strains of bacteria ranged from 8 to 500 micrograms/ml. The modal value of the MIC was found to be 62 micrograms/ml, 64% of the strains tested being inhibited at this concentration. A concentration of 250 micrograms/ml of chlorhexidine inhibited the growth of all bacteria in the 25 subgingival plaque samples investigated. The MIC of chlorhexidine for the samples ranged from 31 to 250 micrograms/ml, the modal value being 125 micrograms/ml.

Adult↗
PubMed1989

Mutations, duplication, and deletion of recombined switch regions suggest a role for DNA replication in the immunoglobulin heavy-chain switch.

The heavy-chain switch from immunoglobulin M (IgM) expression to IgA expression is mediated by a recombination event between segments of DNA called switch regions. The switch regions lie two to six kilobases upstream of the mu and alpha constant region coding segments. Switch recombination to IgA expression results in a recombinant mu-alpha switch region upstream of the expressed alpha constant region gene. We have characterized the products of switch recombination by a lymphoma cell line, I.29. Two sets of molecular clones represent the expected products of simple mu to alpha switches. Five members of a third set of molecular clones share the same recombination site in both the mu and the alpha switch regions, implying that the five molecular clones were derived from a single switch recombination event. Surprisingly, the five clones fall into two sets of sequences, which differ from each other by several point mutations and small deletions. Duplication of switch region sequences are also found in these five molecular clones. An explanation for these data is that switch recombination involves DNA synthesis, which results in nucleotide substitutions, small deletions, and duplications.

Animals↗
PubMed1989

Attitude toward and experience of industry-based alcohol recovery programmes: a survey of 161 Scottish organizations.

This paper reports the results of a survey of 161 Scottish organizations which asked questions in four areas: attitudes of employers toward alcoholism, present disciplinary practice on alcohol-related behaviours, structural features of firms relevant to their policy in discipline in this matter, and employers' views on support available in implementing a work-based alcohol-recovery programme. Results indicated (a) favourable attitudes toward the treatment of alcoholism generally but some doubt as to the practicalities of work-based programmes, (b) a proportion of firms (25.5%) with some form of alcoholism policy, (c) written programmes being associated with firms employing a more skilled workforce and possessing a large personnel department, (d) a willingness by employers to use external voluntary agencies in a recovery programme.

Alcoholism↗
PubMed1989

A specific diagnostic antigen of Echinococcus granulosus with an apparent molecular weight of 8 kDA.

An echinococcus antigen with an apparent molecular weight of 8 kDa was identified as diagnostically important. An immunoblot assay using this antigen was 91% sensitive for surgically confirmed Echinococcus granulosus hydatid disease of the liver. Specificity was 100% for echinococcosis. Marked cross-reactivity was observed with serum specimens from patients with E. multilocularis and E. vogeli infections. The 8 kDa component was not related to the widely recognized echinococcus antigen 5.

Animals↗
PubMed1989

Differentials in Australian interstate migration 1911-21 to 1961-66 by place of birth, sex and age.

"Without direct census data on migration prior to 1971, there is a deficit of information on Australian interstate migration this century. This paper uses the Census Enumeration Ratio technique to produce estimates of net interstate migration by birthplace, sex and age for the intercensal periods between 1911 and 1966. Contrasts in the propensity to migrate of different segments of the population are revealed. These correspond with overseas research and Australian findings for the subsequent period."

Age Factors↗