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Biomedical subjects

H Smith

Publications and source records attributed to H Smith.

At least 685 records · Page 38Linked to original sources
PubMed1976

The adherence of pilate and non-pilate strains of Neisseria gonorrhoeae to human and guinea-pig epithelial tissues.

Strains of Neisseria gonorrhoeae adhered to pieces of human endocervix and appeared to be embedded in the surface mucus. Although a pilate strain adhered better than a non-pilate strain, the difference was small and pilation did not appear to be exclusively responsible for adherence. The pilate strain showed better adherence to pieces of human ectocervix and fallopian tube, but both strains were similarly adsorbed to human bronchus and guinea-pig uterus, cervix, male urethra and bladder, although to different degrees for different tissues. Since gonococci adhered to all tissues examined, their ability to infect human endocervix and fallopian tube and their failure to infect human ectocervix or guinea-pig urogenital tract mucosae are determined by factors other than a capacity for primary adherence to the tissue.

Adhesiveness↗
PubMed1976

Antigenic properties of polymers formed by beta-lactam antibiotics.

Purified polymers have been isolated from 6-aminopenicillanic acid and from semi-synthetic penicillins and cephalosporins. All the polymers were shown to react with rabbit antibody of penicillins and cephalosporins. All the polymers were shown to react with rabbit antibody of penicilloyl specificity, as demonstrated by passive cutaneous anaphylaxis in guinea pigs, and the reactions were shown to be penicilloyl-specific by hapten inhibition experiments. The cephalosporin-derived polymers in addition reacted with rabbit antibodies raised to the corresponding cephalosporin conjugates of bovine gamma-globulin. Using direct skin tests, passive cutaneous anaphylaxis and an in vitro assay, no evidence was obtained that the polymers induced the formation of specific antibodies in baboons, guinea pigs and rabbits, but in baboons the induction of cell-mediated immunity, demonstrable by delayed skin test reactions, was shown.

Ampicillin↗
PubMed1976

Increased vascular permeability during passive peritoneal anaphylaxis in the rat. The effects of disodium cromoglycate and a nitroindanedione.

Following intraperitoneal sensitisation of rats with rat serum containing reaginic antibody, intravenous injection of blue dye and intraperitoneal challenge with antigen caused a release of histamine, slow-reacting substance of anaphylaxis (SRS-A) and dye into their peritoneal fluids. The times taken to reach peak concentrations after challenge were less than 2 min for histamine and between 5 and 10 min for SRS-A, whilst concentrations of dye were still increasing after 2 1/2 h. The amounts of histamine released by antigen were sufficient to account for about 60% of this extravasation of dye. Disodium cromoglycate (DSCG) and a nitroindanedione (BRL 10833) inhibited extravasation by inhibition of mediator release. BRL 10833, unlike DSCG, was active after oral administration, and for a given inhibition of histamine release it produced a greater effect on extravasation when given orally than when injected intraperitoneally.

Administration, Oral↗
PubMed1976

The natural history of trifascicular disease following permanent pacemaker implantation. Significance of continuing changes in atrioventricular conduction.

Seventy-two patients with trifasicular disease were followed for an average of 40 months following permanent pacemaker insertion. The indications for pacemaker insertion were either electrocardiographic evidence of complete heart block with a wide QRS escape complex or a pattern of bifasicular block with either periods of Mobitz type II atrioventricular (A-V) block or a documented history of syncope. The patients were then divided into three groups depending on subsequent change in A-V conduction. There were 31 (43%) patients with no change in A-V conduction, 17 (24%) with increasing A-V block, and 24 (33%) with decreasing A-V block. The characteristics of these three groups, including age and sex distribution, were compared and found to be similar. The incidence of previous transmural myocardial infarction as determined by electrocardiographic criteria was higher in the group with decreasing block. Survival curves showed a significantly decreased probablity of surviving for those with decreasing block compared to both those with increasing block and those with no charge in conduction (P less than 0.03). We conclude that the probability of long-term survival was less in the group with decreasing block. This finding may be related to the greater prevalence of coronary heart disease in the patients.

Aged↗
PubMed1976

The behaviour in ferrets of two closely related clones of influenza virus of differing virulence for man.

Clones 7a and 64d of the recombinant influenza virus A/PR/8/34-A/England/939/69(H3N2) which are of different virulence for man as judged by clinical score (7a more virulent than 64d) showed similar differences in ferrets. With intranasal inoculation the approximate 50% minimal infectious doses of both clones were similar (between 10(0) and 10(2) EID(50)) as were their titres in nasal washes 24 h after inoculation and the histologically evident damage they caused in the nasal turbinates. However, clone 7a persisted in the nasal washes more than 64d and produced a more prolonged pyrexia. Furthermore, 7a consistently produced a lung infection which was produced only occasionally by 64d and then to a lesser extent than 7a. In contrast to nasal mucosa, histological damage in the lung was slight with both strains. Differences in replication of 7a and 64d in organ cultures of nasal turbinates appeared only after 24 h incubation. They were not sufficiently large to explain the markedly superior ability of 7a to persist in the nasal tract in vivo. This persistence, which coincides with the production of pyrexia, may be due to a greater ability of 7a to resist induced systemic host defences. Spasmodic isolations of infective virus of both clones were made from extra-respiratory tissues such as liver, spleen and kidney.

Animals↗
PubMed1975

Regulation of phenylalanine ammonia-lyase synthesis by cinnamic acid. Its implication for the light mediated regulation of the enzyme.

1. There is an increase in the extractable acitivity of phenylalanine ammonia-lyase following excision of hypocotyl segments of dark-grown gherkin seedlings This increase is prevented by the reaction product, cinnamin acid. 2. Density-labelling experiments show that cinnamic acid affects the rate of enzyme synthesis. By contrast the regulation of phenylalanine ammonia-lyase activity by light has previously been shown to involve activation of existing inactive enzyme. 3. It is proposed that regulation of synthesis by reaction products represents a mechanism for controlling the size of the pool of phenylalanine ammonia-lyase, and that the activity of this pool is regulated by light.

Acid Phosphatase↗
PubMed1975

Penetration of penicillin into human phagocytes containing gonococci.

Human phagocytes that had ingested gonococci were incubated with increasing concentrations of penicillin in fresh human serum. Viable counts on phagocyte deposits before and after incubation indicated penicillin penetration at high concentrations but not at lower concentrations which were sufficient to kill extracellular organisms. With lower concentrations significant intracellular survival of gonococci occurred.

Gonorrhea↗
PubMed1975

Prostaglandin synthesis by rheumatoid synovium and its stimulation by colchicine.

The synthesis of prostaglandins by rheumatoid synovial tissue in organ culture was studied utilizing radioimmunoassay, with antisera to PGB1, PGF1alpha and PGF2alpha. It was established that PGE2 and PGF2alpha were the major prostaglandins formed by analyses of culture media with the two antisera to PGF, before and after alkali treatment. Indomethacin at 5 mug/ml suppressed prostaglandin synthesis, usually to less than 1% of control cultures. Colchicine, 0.1 mug/ml resulted in marked stimulation of prostaglandin synthesis, in some cases over 10 fold. It is suggested, because of the colchicine effect, that the state of the microtubules may regulate the rate of prostaglandin biosynthesis. It is possible that prostaglandin E2 produced by rheumatoid synovia may contribute to the pathogenesis of the inflammatory reaction and lead to destruction of juxta-articular bone in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1975

Antiallergic activity of 4-hydroxy-3-nitrocoumarins.

Twenty-four substituted 4-hydroxy-3-nitrocoumarins have been prepared for nitration of the corresponding 4-hydroxycoumarins. All were found to possess antiallergic activity as measured by the homocytotropic antibody-antigen induced passive cutaneous anaphylaxis reaction in the rat.

Animals↗