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Biomedical subjects

R S Griffiths

Publications and source records attributed to R S Griffiths.

8 recordsLinked to original sources
PubMed1992

The sequestration of [3H]spiperone by lymphocytes in schizophrenics and their first-degree relatives: a limited vulnerability marker?

The sequestration of [3H]spiperone by lymphocytes was studied in preserved cells obtained from 22 schizophrenic subjects and 40 of their relatives, and the results were compared with those obtained from 25 healthy control subjects. Mean displaceable sequestration values, obtained from measurements made at a single radioligand concentration (1nM) which optimised the relative contribution of "high affinity" sequestration, were found to be similar for all groups of subjects. Furthermore, displaceable spiperone sequestration was abnormally high in only a small proportion of the schizophrenics (13.6%) and their relatives (5%). There was no evidence that either exposure to neuroleptic medication or duration of illness had an effect on sequestration values. The results suggest that, at least until the required experimental conditions are better established, [3H]spiperone sequestration by lymphocytes does not offer a useful vulnerability marker for schizophrenia.

Adolescent↗
PubMed1977

Effects of chronic renal disease on thyroid hormone metabolism.

Serum concentrations of total and free thyroxine and triiodothyronine together with urine losses of unconjugated thyroid hormones have been measured in normal subjects and in patients with renal disease. Serum total hormone values in the hypothyroid range were common the renal group and correlated inversely with the degree of renal impairment but not with renal loss of hormone which in the case of thyroxine exceeded the average normal daily loss ten-fold. The euthyroid state of patients with renal disease was best reflected by serum free thyroxine concentration which in every case was within the normal range. Poor correlation was apparent between the respective urine concentrations of albumin and thyroxine, and the reasons for this are discussed.

Adolescent↗
PubMed1976

Effect of a single dose of dexamethasone on serum concentrations of thyroid hormones.

In ten euthyroid subjects, in whom endogenous thyroid-stimulating hormone (T.S.H.) production was suppressed by oral thyroxine (T4), a single dose of dexamethasone resulted in reduced serum-3,3'5-triidothyronine (T3) concentration and raised serum-3,3',5'-triiodothyronine (reverse T3 or rT3) concentration after 24 h. These changes were not related to changes in free hormones or binding proteins. Adrenal glucocorticoids may have a pathophysiological role in modulating the peripheral metabolism of thyroid hormones in stress.

Adult↗
PubMed1976

Measurement of serum 3,3',5'-(reverse) T3, with comments on its derivation.

A radioimmunoassay for the measurement of l-3,3',5'-triiodothyronine (reverse TO, rT3) has been developed for use with unextracted serum. The highly specific antiserum showed no cross-reactivity with l-3,3'5-triiodothyronine (T3) or tetradiodothyroacetic acid (T4A) and cross-reaction with L-thyroxine (T4) was low enough to be discounted for routine assay purposes. If a normal amount of rT3 was added to serum T4 cross-reactivity decreased considerably. Serial dilutions of hyperthyroid sera gave dose-response curves which were parallel to the rT3 standard curve. Serum concentrations of rT3 (mean+/- SEM) were 0-68 +/- 0-02 nmo1/1 in sixty-seven normal subjects, 0-19 +/- 0-02 nmo1/1 in twelve hypothyroid patients and 1-18 +/- 0-12 nmo1/1 in seventeen hyperthyroid patients. In sixteen patients with TO-toxicosis rTO was 0-42 +/- 0-04 nmo1/1 and eighteen patients with high circulating TBG had a mean rT3 of 0-54 +/- 0-03 nmo1/1.

Antibody Specificity↗
PubMed1976

Altered patterns of thyroid hormones in serum and urine in pregnancy and during oral contraceptive therapy.

Serum total, percentage free fraction and absolute serum free hormone concentration of thyroxine and triiodothyronine were measured in control, pregnant and oral contraceptive users, together with the daily urinary losses of unconjugated thyroid hormones. Increased urinary losses of both hormones, in particular thyroxine, were apparent in pregnancy and these could not be explained in terms either of an increased filtered load of hormone or the presence of proteinuria. The possible existence of filterable small-molecular weight hormone-binding substances in the urine of pregnant patients is discussed. It is concluded that assay of urinary thyroid hormones during pregnancy is of limited diagnostic value because of overlap with thyrotoxic values.

Adult↗