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Biomedical subjects

R John

Publications and source records attributed to R John.

At least 163 records · Page 9Linked to original sources
PubMed1982

An automated immunoradiometric assay of thyrotrophin (TSH) in dried blood filter paper spots.

An immunoradiometric two-site assay for thyrotrophin (TSH) in dried blood filter paper spots is described. The assay is automated by means of the Kemtek 3000 automated immunoassay system. The technique uses a 6.0 mm disc punched from the dried blood samples collected as part of the screening programme for phenylketonuria. The method is sensitive and precise, and results correlate well with those obtained in TSH assays of serum samples. The procedure is rapid, results being available within 24 h of receipt of samples. Of 25 204 specimens so far screened by this assay, 99.9% have TSH levels less than 15 mU/l. One false positive result has been obtained and six confirmed cases of neonatal hypothyroidism detected, giving a prevalence of 1 in 4200.

Autoanalysis↗
PubMed1981

Lithium therapy and thyroid function: a long-term study.

Seventy-three patients who had been continuously receiving lithium carbonate for 6 months or more had their thyroid function evaluated clinically and biochemically. Goitre was found in 37%, exophthalmos in 23%, positive thyroid auto-antibodies in 24% and abnormal TRH tests in 49%. It would appear that thyroid failure due to lithium is usually dependent on antibody mediated damage. It is unlikely that lithium has a direct effect on the hypothalamic-pituitary axis.

Adolescent↗
PubMed1981

Automated radioimmunoassay of total and free thyroxine in human serum.

A rapid, automated method for the measurement of total and free thyroxine in serum by radioimmunoassay is described. The method uses a commercially available antiserum covalently coupled to finely divided cellulose. A non-equilibrium reaction provides a very fast procedure: 80 samples can be analysed for total and free thyroxine within 3 hours using the Kemtek 3000 automated immunoassay system. The method also has the advantage that a small sample volume (6.25 microliter) is required and that it yields high precision. Serum total and free thyroxine concentrations in healthy euthyroid subjects, pregnant women, and hyperthyroid and hypothyroid patients are reported.

Female↗
PubMed1980

The effect of propranolol withdrawal on thyroid hormones in normal and hyperthyroid subjects.

Blood thyroid hormone levels were measured during, and for 6 days after, treatment with propranolol (160 mg/day, 4-8 weeks) in five hyperthyroid patients and six normal volunteers. In hyperthyroid patients triiodothyronine (T3) and free triiodothyronine index (FT3I) rose to peak levels 60 h after propranolol withdrawal without significant change in thyroxine (T4) or Thyopac-3 test. In normal subjects no significant change in thyroid hormone levels was seen during propranolol treatment or withdrawal. The rise in T3 and FT3I coincides with, and may contribute to, the rebound increase in adrenergic activity after propranolol withdrawal in hyperthyroidism.

Adult↗
PubMed1980

The effect of oxprenolol, acebutolol and propranolol on thyroid hormones in hyperthyroid subjects.

Serum thyroid hormone levels were measured before and during 10 days treatment with acebutolol (400 mg/day), oxprenolol (160 mg/day) and propranolol (160 mg/day) eighteen hyperthyroid patients. A significant change in thyroid hormone concentrations was seen only in the group treated with propranolol. Propranolol should be used in preference to beta-adrenoreceptor blocking drugs with partial agonist activity, in the treatment of hyperthyroidism.

Acebutolol↗
PubMed1979

[Critical considerations on the production of a pulsating fluid stream].

Two types of gears are used for perfusion of cadaveric kidneys. Electric models are presented for both types and the optimal devices are discussed. Based upon in vivo conditions, the relevant parameters are transferred to the model and an according equipment for pulsatile fall-stream perfusion is presented, which is compared with another gear. The clinical criterion for good initial perfusion is the erythrocyte count in the initial perfusate. Judged from that, the chosen device is significantly better than its predecessor.

Biophysical Phenomena↗
PubMed1974

The nature of the multiple forms of cytoplasmic aspartate aminotransferase from pig and sheep heart.

Starch-gel electrophoresis of sheep heart aspartate aminotransferase was carried out over the range pH7.0-8.5. The enzyme separates into three subforms in the same way as the pig heart enzyme. As the pH was increased the distance migrated by each subform increased by the same amount, so that they remained the same distance apart. Titration of the enzyme over the appropriate pH range was used to calculate the difference in charge between the subforms and it was concluded that they differ by one charged group per dimer from their nearest neighbour on the electrophoretogram over the whole pH range studied. It was also shown that the pig-heart alpha and beta subforms differ by almost one charged group per dimer in the range pH5.5-5.7 and that the spacing between the subforms on starch-gel electrophoresis at pH8.0 is the same as that for the sheep enzyme. Since the charge difference between the subforms is maintained over such a wide range of pH, it is concluded that they probably differ from each other in covalent structure, because of the improbability that conformational differences can give rise to such behaviour. The relationship between the subforms and inactive binding of the coenzyme is also examined.

Animals↗