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Biomedical subjects

S A Jones

Publications and source records attributed to S A Jones.

At least 145 records · Page 8Linked to original sources
PubMed1986

Smoking in hospital--a survey of staff attitudes at Westminster Hospital.

A survey of staff attitudes to smoking and facilities for smokers and non-smokers at Westminster Hospital and associated buildings revealed widespread support for firmer measures to limit and control smoking on health service premises. The survey was eventually undertaken with the agreement of staff side union representatives who had initially resisted the health authority's wish to implement a policy on smoking. In the event, the results provided support to the TUC's 1981 Resolution calling for increased smoking restrictions in workplaces as part of an overall policy to reduce smoking prevalence among working people, which has been followed up in local initiatives by unions throughout the country.

Attitude of Health Personnel↗
PubMed1986

Effects of porcine relaxin on the length of gestation and duration of parturition in the rat.

Experiments were carried out to investigate the effects of porcine relaxin on the course of gestation and delivery in the rat. Plasma relaxin was maintained at approximately 600 nmol/l from day 19 to day 23 of gestation by i.v. infusion from chronically implanted minipumps. Relaxin significantly (P less than 0.001) prolonged the length of gestation in 17 rats compared with controls, without causing dystocia or affecting the number of live births. Six rats gave birth during relaxin infusion. In these animals there was a significant (P less than 0.001) increase in the interval between successive deliveries compared with control animals, resulting in prolonged labour. The remaining 11 rats gave birth after the infusion was completed, when the interval between successive deliveries was significantly (P less than 0.025) shorter than controls. The results are consistent with the hypothesis that relaxin has a central action suppressing the release of oxytocin as well as a peripheral action on the myometrium and cervix.

Animals↗
PubMed1986

Relaxin acts centrally to inhibit oxytocin release during parturition: an effect that is reversed by naloxone.

Experiments were carried out to establish whether infusion of relaxin prolongs gestation and labour in the rat by suppressing release of oxytocin, and whether the effects of relaxin on birth could be reversed by the opioid antagonist naloxone. Female rats were implanted with subcutaneous osmotic minipumps for the infusion of purified porcine relaxin into the jugular vein for 84 h from either day 19 or day 20 of gestation. Infusion of relaxin delayed the onset of labour and in those animals which delivered during relaxin infusion, delivery was longer by approximately 45 min. Plasma oxytocin levels 40 min after delivery of the first fetus were 45.25 +/- 3.6 pmol/l (mean +/- S.D.) in unoperated controls and significantly (P less than 0.01) depressed (23.89 +/- 3.9) in rats that delivered during infusion of relaxin. Rats that delivered after the infusion of relaxin had finished, gave birth significantly (P less than 0.05) faster than controls and plasma oxytocin levels were significantly (P less than 0.01) raised (77.87 +/- 15.9 pmol/l). Naloxone treatment (1 mg/kg; i.m.) given immediately after the delivery of the first fetus reversed the inhibitory effect of relaxin and the interval between successive deliveries was slightly faster than that of controls. Plasma oxytocin levels in relaxin-infused naloxone-treated rats were significantly (P less than 0.01) higher than values in unoperated control rats. The results confirm that relaxin suppresses oxytocin release possibly through an opioid system and this may be important in the control of the timing of birth.

Animals↗
PubMed1984

Monoclonal antibody with hemagglutination, immobilization, and neutralization activities defines an immunodominant, 47,000 mol wt, surface-exposed immunogen of Treponema pallidum (Nichols).

Radioimmunoprecipitation (RIP) analyses performed on 125I-surface-labeled Treponema pallidum cells using various immune sera revealed the presence of six major surface antigens (immunogens) with apparent molecular weights of 47 K, 36 K, 34 K, 32 K, 29 K, and 13 K. Among these, the 47 K surface antigen was most abundant. Radioimmunoprecipitation assays using 125I-labeled T. phagedenis biotype Reiter or immunoblot analyses using the same strain, failed to reveal the presence of the 47 K mol wt antigen in the representative nonpathogenic treponeme. Preabsorption of anti-T. pallidum immune rabbit serum (IRS) with the Reiter organism did not remove anti-T. pallidum antibodies from immune serum that reacted with the 47 K mol wt immunogen or other immunogens of T. pallidum present in the characteristic antigenic profile. Monoclonal antibodies (mAb) directed specifically against the 47 K mol wt immunogen of T. pallidum also failed to react with an analogous 47 K mol wt component in Treponema phagedenis biotype Reiter, further suggesting the unique presence of this antigen in pathogenic treponemes. The presence of the 47 K mol wt surface immunogen in pathogenic treponemes other than T. pallidum subspecies pallidum was also observed (43). Anti-47 K immunogen mAb was nonreactive against rabbit IgG or IgM. mAb directed specifically against the 47 K mol wt immunogen of T. pallidum was examined for strategic functional activities. It was found to be reactive in the microhemagglutination assay for T. pallidum antibodies, the T. pallidum immobilization test, and was found to be capable of significant blockage of attachment of virulent T. pallidum to host cells in tissue culture. Additional significant biological activity for the anti-47 K mol wt immunogen mAb was revealed through results of the in vitro-in vivo neutralization test of Bishop and Miller, in which a 99% or 100% neutralizing activity was demonstrated. The combined data of this study suggest that the 47 K mol wt immunogen of T. pallidum represents an abundant, immunodominant, surface-exposed immunogen possessing potential biological importance in the pathogenesis and immunology of T. pallidum infection. These studies serve to establish the first functionally defined immunogen for T. pallidum, which may represent the major immunogen of the organism.

Animals↗
PubMed1984

Monoclonal antibody analysis of specific antigenic similarities among pathogenic Treponema pallidum subspecies.

Murine monoclonal antibodies directed against a 47,000-dalton immunodominant surface-exposed antigen of Treponema pallidum subsp. pallidum (Nichols) were isolated. These monoclonal antibodies cross-reacted with analogous 47,000-dalton antigens of two other virulent treponemes, T. pallidum subsp. pertenue and T. pallidum subsp. endemicum (Bosnia A), as determined by radioimmunoassay and immunoblot analyses. Immunoelectron microscopy confirmed that the 47,000-dalton antigen of T. pallidum subsp. pallidum was a surface-associated cellular component. Surface binding assays and immunoelectron microscopic studies also suggested that the analogous 47,000-dalton antigenic component of T. pallidum subsp. pertenue may not have been oriented toward the bacterial surface in the same way as the T. pallidum subsp. pallidum antigen or that the relevant antigenic determinant(s) may not have been exposed to the outer surface in the same way. The significance of this antigen relative to its apparent conservation among pathogenic treponemes and its possible diagnostic and vaccinogenic potentials are discussed.

Animals↗
PubMed1983

Cloning and expression of the Staphylococcus aureus protein A gene in Escherichia coli.

A gene bank of Staphylococcus aureus strain Cowan I was established using an E. coli HB101/pBR327 host-vector system. Recombinants expressing staphylococcal protein A (SPA) were detected using an IgG-binding assay. A 3.2 Kb DNA fragment directing the synthesis of SPA in E. coli was identified. SPA produced by E. coli was characterised in minicells and by Western blotting and double diffusion experiments.

Base Composition↗
PubMed1982

Assessment of drugs for activity in established type II collagen arthritis.

Arthritis was induced in a proportion of rats sensitized with type II collagen and Freund's incomplete adjuvant. Rats which developed arthritis had significantly higher antibody titres and significantly greater delayed hypersensitivity responses to type II collagen than rats which did not develop arthritis. Anti-inflammatory and anti-rheumatic drugs were evaluated against type II collagen arthritis. Dexamethasone reduced inflammatory swelling, reduced both the antibody titre and delayed hypersensitivity to type II collagen and exerted joint protection. Indomethacin reduced inflammatory swelling. Azathioprine, Clozic, Levamisole, D-Penicilamine and Sulphapyridine did not exert significant beneficial activity in this test.

Animals↗
PubMed1980

Nonuniform epicardial depolarizations during coronary occlusion in dogs.

Epicardial electrograms were recorded before and after occlusion of the left anterior descending coronary artery. The greatest difference between the post-occlusion and pre-occlusion depolarization times were determined. These times were referred to as the normalized times of greatest disparity, delta tmax. It was found that following both one- and two-stage occlusion of the LAD there was a significant increase in delta tmax in the ischemic area of the myocardium. This indicates increased asynchrony of depolarization. However, no significant change in depolarization times occurred in the unaffected area. In one-stage occlusion with an increase in delta t max there was a linear correlation with the development of ventricular arrhythmias, especially ventricular premature beats and tachycardia. Thus, there is evidence which links the increase in depolarization times with the mechanism of reentry and ventricular arrhythmias.

Animals↗
PubMed1979

Effects of thioridazine (Mellaril) on ventricular electrophysiologic properties.

The effects of therapeutic and toxic doses of thioridazine (Mellaril) (10 and 50 mg/kg body weight, respectively) on ventricular electrophysiologic properties were studied in 12 anesthetized dogs. Threshold pacing currents (diastolic threshold), effective refractory period and conduction time were significantly increased, and idioventricular automaticity was suppressed after administration of 10 mg/kg of thioridazine; the effects were much more pronounced after administration of 50 mg/kg. Rapidly repetitive responses or tachycardia could be induced in the ventricle by two early premature beats in 9 of the 12 dogs after the 50 mg/kg dose, but they did not occur before drug administration or after the 10 mg/kg dose. These results indicate that the antiarrhythmic and arrhythmogenic effects of thioridazine are dose-dependent and that careful monitoring with frequent electrocardiograms is needed for patients receiving large doses of this drug.

Animals↗