R. McG. Harden

EXAMINATION OF CLINICAL EXAMINERS

Abstract The poor correlation between the marks awarded in the clinical tests in medicine and surgery, and between the medical clinical test and the written objective paper, suggested the need for more detailed investigations into the reliability of clinical examinations. Two examiners independently marked 29 candidates in a clinical examination in medicine, and the marks awarded were compared. In another examination 28 different students were examined on one short case by two examiners and the examination was recorded on videotape. This was subsequently marked by a further twelve examiners and again on two further occasions by the original examiners. Marks awarded by one examiner often varied considerably from those awarded by another examiner for the same performance. Inconsistency in the same examiner was also evident. This observed variation must be more widely recognised in determining the fate of candidates in clinical examinations.

ISOTOPE UPTAKE AND SCANNING OF STOMACH IN MAN WITH 99mTc-PERTECHNETATE

Abstract The stomach can be displayed in man by means of the isotope, 99m Tc-pertechnetate. This isotope is concentrated by the stomach and the uptake can be quantitated by a radioisotope scanning procedure. The gastric uptake is significantly higher than that of the thyroid or the salivary glands. The isotope was completely discharged from the stomach 40 minutes after potassium-perchlorate administration. Wider experience is needed in order to establish the precise role of isotope scanning of the stomach in the investigation of gastric function and disease.

An experiment involving substitution of tape-slide programmes for lectures.

Abstract A group of 4th year students were taught part of an endocrinology course by programmed tape-slide presentations in place of conventional lectures. Kindermann audiovisual tutor machines and audio-tape cassette players with automatic hand viewers were used. The students taught in this way significantly improved their positions in the class and reacted favourably to the experiment.

LONG-TERM TREATMENT OF HASHIMOTO'S THYROIDITIS WITH THYROXINE

Abstract Thyroid function was assessed in Summary twelve patients with Hashimotos thyroiditis at the time of diagnosis, after 10 years on thyroxine therapy, and 6 weeks after stopping thyroxine (T4). Before therapy five patients were hypothyroid and seven were euthyroid. Goitre size decreased significantly in eleven patients during thyroxine therapy. The destructive process in Hashimotos thyroiditis was not arrested by treatment with thyroxine. Evidence for this was that the mean serum-level of protein-bound iodine-127 (P.B. 127 I) fell significantly from 3·1 before T4 therapy to 1·6 6 weeks after stopping T4. There were significant falls in 48-hour 131 I uptake, P.B. 131 I, thyroid clearance, and absolute iodine uptake. Two patients in whom the precipitin test had initially been positive developed negative tests after 10 years and had low or negative tanned-red-cell (T.R.C.) titres. Two patients became negative for microsomal antibody over the 10-year period. There was no

A follow-up of thyrotoxic patients treated by partial thyroidectomy.

Abstract Eighty-four of eighty-eight thyrotoxic patients treated by thyroidectomy 2-9 years previously have been studied. In 11% of the patients the thyrotoxicosis recurred and 5% of patients became hypothyroid. Only half of these patients had been diagnosed before review. Thyrotoxicosis tended to recur in those patients with larger goitres and high pretreatment 131 I-uptake values. Patients who became hypothyroid had more evidence of thyroiditis. Routine thyroid-function tests may be misleading after thyroidectomy. High radioiodine-uptake values and thyroid clearances may occur associated with a low plasma-inorganic-iodine and a normal absolute iodine uptake by the thyroid. Late thyroiduptake measurements are of little diagnostic help, and the protein-bound- 131 I is frequently raised in the euthyroid patient. Estimation of the serum-protein-bound 127 I completely separated the euthyroid, thyrotoxic, and hypothyroid patients, although some euthyroid patients had low normal values. Three patients had unilateral cord paralysis, but in only one was this permanent. No patient had clinical evidence of parathyroid insufficiency, but as a group the serum-calcium and phosphate-excretion index tended to be low.

Some aspects of the absorption and concentration of iodide by the alimentary tract in man.

SYMPOSIUM PROCEEDINGS I967 disease is furthermore often associated with chronic pancreatic damage. It is therefore interesting to find that patients with cirrhosis often have markedly increased iron absorption and that this can be reduced towards normal on giving the test dose with pancreatin (Callender, 1965). In an attempt to elucidate further the part played by the pancreas in iron absorption, Helen Brown (unpublished), in our laboratory, produced pancreatic damage with ethionine in rats on a restricted protein intake. She investigated the absorption in two groups of rats, one given an iron supplement and one iron-deficient. These groups were further subdivided into those with and those without pancreatic damage. Iron absorption in the rats with the iron supplement was increased in those with pancreatic damage and addition of pancreatin restored absorption to normal, but in the iron-deficient rats the findings were reversed, i.e., pancreatic damage was accompanied by diminished iron absorption which was restored to control values by the addition of pancreatin. These contradictory findings emphasize the complexity of the problems of iron absorption. In these few remarks I have only touched on some of the factors which affect iron absorption. Iron deficiency remains one of the world’s greatest nutritional problems and until we learn a great deal more about the complex mechanisms and interactions of the many factors concerned in the control of iron absorption, it is likely to remain with us.

The effect of metronidazole on thyroid function and exophthalmos in man

Abstract The effect of metronidazole (Flagyl), 400 mg. three times daily, on thyroid function and exophthalmos has been studied. There was no significant change in thyroid function as measured by thyroid uptake of radioiodine, thyroidal iodine clearance, absolute iodine uptake (AIU) by the thyroid, serum PBI, triiodothyronine resin uptake, plasma inorganic iodine (PII) concentration or renal iodide clearance, in either euthyroid or thyrotoxic patients. In a blind trial, there was a significant decrease in endocrine exophthalmos in patients treated with metronidazole for three months. When the drug was stopped, the exophthalmos increased. Side effects, especially nausea and an unpleasant taste in the mouth, were relatively common in the dosage used.

The effect of total fasting on thyroid function in man.

Abstract Serial studies of iodine metabolism were carried out in 8 obese patients before and during total deprivation of food. Evidence of decreasing thyroid function was suggested by a fall in uptake of both radioactive and stable iodine by the gland and by a fall in serum protein-bound iodine. The renal clearance and urinary excretion of iodine also fell. The amount of thyroid hormone deiodinated was calculated as 45.5 and 39.5 μg. of hormonal iodine daily.

Quantitative studies of the inhibitory effect of perchlorate on the concentration of 36ClO4−125I− and 99mTcO4− in salivary glands of male and female mice

[36Cl]-Perchlorate, [125I]-iodide and [99mTc]-pertechnetate were concentrated in the mouse submandibular salivary gland in the order 36ClO4− = 99mTcO4− >125I−. Gland plasma (GP) concentration ratios for 36ClO4− and 99mTcO4− rose to a maximum of 12 compared to a value of five for 125I−. In the case of all the anions studied, a significantly higher concentration was observed in male compared to female mice. This anion concentration difference between the sexes was of the same order for 36ClO4− and 99mTcO4− and was smaller in the case of 125I−. Results suggest that 36ClO4− is concentrated in the duct cells of the salivary gland. The serum perchlorate levels required to decrease the (GP) ratio to 1 varied for the different anions and was in the order 99mTcO4− >36ClO4− >125I−. The concentration of perchlorate required to inhibit the concentrating mechanisms for the three anions was greater in males than females. The lowest dose of ClO4− used (0.28 μ-equiv./kg) was such that it did not inhibit 125I−or 99mTcO4− uptake in either sex. With a dose of 1.43 μ-equiv./kg, the ClO4− concentrating mechanisms for 125I− and 99mTcO4− were inhibited in the female but not in the male.

Sex differences in human parotid salivary secretion of iodide, pertechnetate and bromide.

Abstract Parotid salivary flow rates were studied using a variety of stimuli in convalescent patients after injection of a solution containing 132I, 99mTcO4− and 82Br. Lemon juice and salt produced significantly higher flow rates in men than in women. However, for any given flow rate there was no significant difference between the sexes in the saliva to plasma ( S P ) ratio produced by any of the anions. The inverse relation between the S P ratio of each of the anions and salivary flow rate was confirmed.