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Biomedical subjects

A F Smith

Publications and source records attributed to A F Smith.

At least 163 records · Page 9Linked to original sources
PubMed1978

Steroid priming of the luteinizing hormone response to luteinizing hormone releasing hormone.

Perifusion experiments were performed to study the stimulatory effects of luteinizing hormone releasing hormone (LH-RH) on the release of LH from anterior pituitary tissue. Exposure of pituitary tissue from normal male rats to LH-RH (5 ng/ml for 5 min) induced a small release of LH; in tissue from ovariectomized rats receiving no pretreatment, the release was more than three times greater and in tissue from gonadectomized male or female rats pretreated with oestradiol benzoate and progesterone, the release was six times greater than that observed in normal rats. Further exposure of pituitary tissue from gonadectomized steroid-pretreated male and female rats to LH-RH (5 ng/ml) induced an increase in the level of LH even greater than that seen after the initial exposure (priming action of LH-RH); in tissue from ovariectomized rats receiving no pretreatment, less LH was released than after the first exposure to LH-RH and in tissue from normal male rats the response was unchanged.

Animals↗
PubMed1978

Connective tissue activation. XII. Platelet abnormalities in patients with rheumatoid arthritis.

Patients with rheumatoid arthritis frequently have an unexplained thrombocytosis which appears to be related to the severity of the disease process. This report shows that rheumatoid platelets have reduced saline soluble protein per 10(9) platelets, less of a lysosomal enzyme, acid phosphatase, and decreased connective tissue activating peptide (CTAP-III) activity. CTAP-III is a potent connective tissue mitogen, and promotes glycolysis and glycosaminoglycan synthesis, characteristics which make it an interesting candidate for a role as a mediator of inflammation.

Acid Phosphatase↗
PubMed1977

The response to inactivated influenza A (H3N2) vaccines: the development and effect of antibodies to the surface antigens.

A controlled trial of influenza vaccines in a boys' public school from November 1970 to October 1975 provided an opportunity to study the response to vaccine and the effect on subsequent natural challenge in boys with differing natural experience of influenza A strains. The response to influenza A (H3N2) vaccines was assessed by estimating homotypic and heterotypic antibodies to the surface antigens. Previous natural experience of influenza A was found to influence vaccine response and the effect of natural challenge. The antibody response to revaccination with the same strain showed a progressively poorer response to second and third doses. The protectitive effect of naturally acquired and vaccine-induced antibodies was assessed during two outbreaks of influenza A which occurred in the trial period.

Antibodies, Heterophile↗
PubMed1976

Biochemical differences between the MB and MM isoenzymes of creatine kinase.

The biochemical properties of partially purified preparations of human myocardial MB and MM iosenzymes of creatine kinase have been compared with one another. Differences in substrate affinity, behaviour with inhibitors, and heat denaturation have been demonstrated. It is doubtful if the differences we have shown are sufficiently great to form the basis of a practical routine procedure for measuring serum levels of the MB isoenzyme.

Adenosine Triphosphate↗
PubMed1976

Creatine kinase MB isoenzyme studies in diagnosis of myocardial infarction.

Serial measurements of the MB isoenzyme of creatine kinase, total creatine kinase, aspartate mainotransferase, and urea stable lactate dehydrogenase have been made in the serum of a series of 139 patients admitted with a diagnosis of suspected myocardial infarction. Serum MB isoenzyme measurements have also been made on postoperative surgical patients and patients with medical disorders known to have caused raised serum total creatine kinase activity. All these enzymes were abnormal in at least one specimen from all patients with electrocardiographically proved acute myocardial infarction. The magnitude of the MB isoenzyme rise was 2 to 3 times greater than that of any of the other enzymes. The duration of its rise was relatively short. The MB isoenzyme was more specific for myocardial infarction than other enzymes and no increases were found in postoperative patients, except in those after cardiac bypass surgery. The MB isoenzyme seems the most sensitive and specific test for myocardial infarction available, though there are technical problems in its accurate measurement.

Adult↗
PubMed1976

Immunoglobulins and complement in pleural effusions associated with bronchogenic carcinoma.

Levels of IgG, IgA, IgM, the total haemolytic complement (CH50), and the individual components C1q, C3, C4, C6, and C7 were measured in 29 pleural effusions. Of these, 18 were associated with carcinoma of the bronchus and 11 were non-malignant effusions including empyemas. The level of IgG was significantly lower in the malignant group when compared with non-malignant effusions. The usefulness of measurements of IgG with respect to malignant effusions associated with carcinoma of the bronchus requires an expanded study to show whether it has any real diagnostic value. There were no significant differences in other immunoglobulins, the CH50, and individual complement components between the two groups. The identification of total haemolytic activity in the majority of effusions in both groups indicates that all nine components of the classical pathway of complement, including macromolecules such as C1, can be present in pleural fluids.

Carcinoma, Bronchogenic↗
PubMed1976

Sea-blue histiocytosis associated with hyperlipidaemia.

A patient with sea-blue histiocytosis in spleen and bone marrow with an accompanying hyperlipidaemia is described. The hyperlipidaemia was due to an increase in "free" cholesterol, lecithin, and triglycerides. Despite these findings lecithin-cholesterol acyl transferase activity was normal. Although the precise biochemical defect was not identified, there was a failure of transport of cholesterol from chylomicrons in vitro. We propose that the sea-blue histiocyte is a marker, in some cases, of abnormal lipid metabolism.

Adult↗
PubMed1976

Experimental infections of sheep with Salmonella typhimurium.

Twenty-two-six-to nine-month-old lambs were infected orally with Salmonella typhimurium at levels varying from 2 x 10(13) to 1 x 10(9) and serially slaughtered to determine the pathogenesis of infection and to evaluate the efficacy of diagnostic procedures. Infection resulted in a severe fatal or potentially fatal clinical disease in lambs receiving 2 x 10(13) organisms. Observations were made on the clinical pathology, bacteriology and serology during the course of infection and extensive bacteriological examinations were undertaken at autopsy.

Animals↗
PubMed1976

Experimental infection of poultry with Salmonella infantis.

Six-month-old cockerels and point-of-lay pullets were infected orally with S infantis (1 X 10(10). The cockerels were slaughtered at intervals up to 42 days, and the pullets slaughtered 20 weeks, after infection. Infection produced no clinical disease and minimal changes were observed at autopsy. Serological responses were transient, frequently absent three to six weeks after infection, no response at all being recorded in some birds. Faecal excretion was observed most frequently during the early stages of infection. There was no evidence of egg transmission.

Animals↗
PubMed1975

The effect of apomorphine and ergocriptine on the release of MSH by the pars intermedia of Rana pipiens.

In an attempt to further characterize the nature of the innervation controlling melanophore-stimulating hormone (MSH) release from the pars intermedia (PI), pellets containing either apomorphine or ergocriptine were implanted in contact with the PI of the frog, and the effect on the animal's coloration was observed. Frogs with apomorphine implants exhibited skin pallor for several hours and those with ergocriptine implants were pallid for a few days. Hypophysectomized (HX) frogs which had been darkened with MSH regained their pallor no sooner when given an injection of apomorphine than with the vehicle. However, intact dark frogs lightened when injected with apomorphine. Frogs darkened by autotransplantation of the PI to the dorsal lymph sac were lightened by an injection of apomorphine. Frogs lightened by an ergocriptine implant on the PI and then darkened by MSH did not lighten sooner than HX frogs given an injection of MSH. Ergocriptine-containing pellets implanted in the thigh took longer to produce the same effect than those implanted in contact with the PI. Since apomorphine is known to stimulate dopamine receptors in the central nervous system, and there is some evidence that ergocriptine does also, the above evidence supports the hypothesis that dopamine receptors are present in the PI.

Animals↗
PubMed1975

Embryonic mortality during the pre- and post-implantation periods of pregnancy in mature mice after superovulation.

Sexually mature mice were stimulated to superovulate by giving exogenous gonadotrophins at known stages of the oestrous cycle. Untreated animals which ovulated spontaneously served as controls. The number of oocytes ovulated by each female was estimated from counts of the number of CL of pregnancy, and the incidence of embryonic mortality during the pre- and post-implantation stages of pregnancy was assessed from the number of zygotes recovered from the reproductive tract at 2-0 and 4-0 days post coitum and of conceptuses examined at 7-5 and 11-5 days post coitum. The mean number of oocytes ovulated by treated animals was 39-54, compared with 12-80 in controls: in mice which had superovulated, 44% of the ova were lost before implantation compared with about 10% in the controls. Further losses occurred about the time of implantation and at mid-pregnancy and thus the number of embryos classified as normal rarely exceeded the maximum found in controls. Death at mid-pregnancy seemed to be preceded by developmental retardation. The possibility that genetic and environmental factors play a role in embryonic loss after superovulation is discussed.

Animals↗