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T Smith

Publications and source records attributed to T Smith.

At least 775 records · Page 43Linked to original sources
PubMed1981

Receptor-mediated vitellogenin binding to chicken oocytes.

The specific binding of vitellogenin to chicken oocyte membranes was characterized. This major hen serum phospholipoglycoprotein and one of its lower-molecular-weight components, phosvitin, bound to oocyte membranes with KD values of approx. 6 x 10-7 M. The optimum pH for binding was 6.0, the same as the pH of yolk contents. Phosvitin and vitellogenin compete with each other for binding; other proteins tested do not compete to the same degree. Phosvitin, which contains 10% phosphate by weight, appears to be the polypeptide recognized by the receptor. RNA failed to compete with either vitellogenin or phosvitin for binding, suggesting that the binding specificity may require more than polymeric phosphate. The binding was tissue-specific in that phosvitin and vitellogenin bound to oocyte surfaces (at both pH 6.0 and 7.5), but not to chicken erythrocytes (at either pH).

Animals↗
PubMed1981

Use of the enzyme-linked immunosorbent assay (ELISA) for the estimation of serum antibodies in an influenza virus vaccine study.

The value of the enzyme-linked immunosorbent assay (ELISA) for determining the serum antibody responses of volunteers following immunisation with various inactivated influenza virus vaccines was assessed, and the incidence of seroconversions, as measured by both haemagglutination-inhibition (HI) and ELISA response of the volunteers determined. ELISA was found to be more sensitive than the HI test in detecting serum antibodies, but was also less specific under the conditions used. With regard to efficacy, the whole virus vaccine proved to be more effective in inducing serum antibody in an unprimed population than either tween-ether split or subunit adsorbed vaccines, but the reverse situation held when the population was primed with respect to the antigen concerned.

Adolescent↗
PubMed1981

Side-chain effects on phenothiazine cation radical reactions.

The cation radical of each of the phenothiazine tranquilizers is a likely intermediate in the metabolism of the drugs to at least two of the three major metabolic classes, the sulfoxides and the hydroxylated derivatives. Previous work has shown that the reactions of the radical are highly dependent on the environment, particularly the presence of nucleophiles. The present report discusses the effect of cation radical structure on the formation of sulfoxide and hydroxylated metabolites in vitro. Cyclic voltammetry, spectrophotometry, and liquid chromatography were used to examine reactions of various phenothiazine radicals in aqueous buffers. A radical with a three-carbon aliphatic side chain (e.g., chlorpromazine) forms solely sulfoxide and parent unless amine nucleophiles are present, in which case hydroxylation occurs. A shorter side chain (e.g., promethazine) causes radical dimerization and pronounced hydroxylation, regardless of external nucleophiles. A piperazine side chain (e.g., fluphenazine) promotes hydroxylation, with some sulfoxide observed. The results indicate that a deprotonated amine is necessary for hydroxylation and that the amine may be present in the original drug rather than an external nucleophile. In addition to information about cation radical reactions, the redox properties of several different phenothiazines are presented.

Cations↗
PubMed1981

Total body potassium in relation to thyroid hormones and hyperthyroidism.

1. Body weight and total body potassium were measured in 23 hyperthyroid patients before and at various stages during treatment and in 19 athyreotic patients who were being treated with high-dose L-thyroxine. 2. In the hyperthyroid patients the total body potassium rose by 23 +/- 2.8% (SEM) within a few weeks of restoring the blood thyroid hormone levels to normal. The body potassium values after treatment were close to that expected in these individuals if they were healthy indicating that a considerable loss of body potassium is usual in hyperthyroidism. 3. The gain of total body potassium in hyperthyroidism averaged 71 +/- 8 mmol for each kg of body weight gained (compared with muscle potassium concentration of about 92 mmol/kg). In contrast, weight loss produced by dietary treatment of obesity caused very little change of body potassium (maximum averaged was 14 +/- 4 mmol/kg wt. loss). 4. Among the patients with hyperthyroidism, the greatest muscular weakness was present in those with the greatest body potassium loss and these patients regained a large amount of potassium relative to weight on recovery. 5. Total body potassium changes were closely related to total plasma tri-iodothyronine concentrations but unrelated to the thyroxine levels.

Adult↗
PubMed1981

Dosimetry of renal radiopharmaceuticals: the importance of bladder radioactivity and a simple aid for its estimation.

The contribution from radioactivity in bladder contents to dose commitments to the embryo, ovaries, red marrow, kidney, bladder wall and total body has been estimated for various renal radiopharmaceuticals, assuming a bladdervoiding period of 3.5 h. For hippuran and GFR agents this contribution is 70-97% of the embryo dose and 50-93% of the ovary dose. The embryo dose exceeds the ovary dose by a factor of two or more. For the radiopharmaceuticals with no significant kidney retention, the surface dose to the bladder wall is higher, by more than an order of magnitude, than doses to other organs and is largely responsible for the effective dose equivalent exceeding the estimated whole-body dose by factors of up to 25. Since the estimation of cumulated activity in bladder contents is necessary for bladder dosimetry, a nomogram based on a 3.5 h voiding period is presented as a convenient aid for this purpose.

Bone Marrow↗
PubMed1981

Auditory electrophysiology: findings in multiple sclerosis.

15 patients suffering from definite multiple sclerosis were studied by electrocochleography (ECochG) and brain stem electric responses (BSER), including objective analysis of the electrophysiological data. In 7 patients, both ECochG and BSER were performed, in 2 only ECochG and in 6 only BSER. Systematic deviations from normative values were found in all 9 patients tested by ECochG, but the deviations occurred only at 75 dB pe SPL or below. Despite normal or near-normal audiometric thresholds, the cochleae seemed to be involved. At click intensities of 95 dB pe SPL or higher, the BSER revealed a normal AP-V (Jewett) interval in all 13 patients tested. However, a deviant configuration of the BSER following the wave V complex was found in 6 of the 13 patients. The deviation is described as a dominant, relatively low-frequency component of the response. The discrepancies between these results and those reported in the literature indicate a strong need for applying methods that compensate for peripheral hearing dysfunctions and objective methods of analysis to identify and evaluate the various components of the evoked potentials.

Adult↗