Neurological damage to the fetus resulting from severe iodine deficiency during pregnancy.

Endemic cretinism is characterised by multiple neurological defects including deaf-mutism, diplegia, squint, and mental deficiency. The condition is widely prevalent in the Highlands of New Guinea in association with severe iodine deficiency. Previous studies have shown that iodised oil provides a very satisfactory correction of severe iodine deficiency in New Guinea. A controlled trial on the use of intramuscular iodised oil in the prevention of endemic cretinism was carried out in the Western Highlands of New Guinea and involved a population of approximately 8000. Subsequent follow-up over four years revealed 26 endemic cretins out of a total of 534 children born to mothers who had not received iodised oil; the mothers of 5 of these cretins were pregnant at the start of the trial. In comparison, 7 cases of endemic cretinism occurred among 498 children born to mothers who had been treated with iodised oil; in 6 of these 7 cases, the mother was pregnant when the trial commenced. It is concluded that intramuscular iodised oil is effective in the prevention of endemic cretinism and that, for it to be effective, it should be given prior to conception. This suggests that severe iodine deficiency in the mother produces neurological damage during fetal development.

The role of the GP in the management of chronic disease. Diabetes as a model.

Chronic disease is increasing as a percentage of all illnesses in Australia's health care system, in part because of the ageing of the population. New strategies are required to help manage these often incurable diseases. The general practitioner is well equipped to provide management expertise for chronic disease, provided he or she has access to community based allied health professionals.

Radionuclide angiographic study of the influence of dietary lipid supplements on cardiac function in the marmoset (Callithrix jacchus).

Radionuclide angiography was used to examine the influence of dietary fat on cardiac function in the common marmoset monkey (Callithrix jacchus jacchus) under barbiturate anaesthesia. Animals were fed for 6-8 months with a low fat (4.5%) reference diet or the same diet supplemented (12%) with sunflower seed oil or sheep fat. Although there was a tendency towards increased heart rate, left ventricular ejection fraction, peak ejection rate, and peak filling rate in both fat supplemented groups, significant increases in heart rate (+50%), peak ejection rate (+71%), and peak filling rate (+84%) were found with sheep fat supplementation, whereas only the vegetable oil supplement produced a significant improvement in left ventricular ejection fraction (+23%). There were no differences in resting blood pressure, and the main consequence of dietary fat supplementation was a major increase in apparent cardiac oxygen consumption (+58%) with the sheet fat diet, as determined by the pressure-rate index. Infusion of isoprenaline hydrochloride (0.2 microgram.kg-1.min-1) increased all indices of cardiac function towards common maxima. There were no differences in either the depth or duration of anaesthesia between dietary groups. It therefore is unlikely that this contributed to any of the observed dietary induced differences in cardiac function. It is suggested that dietary saturated animal fat increased cardiac work and oxygen consumption at rest to the extent that functional reserve to respond to stress was significantly diminished. Feeding a linoleic acid rich polyunsaturated vegetable oil supplement was, however, accompanied by evidence of some improvement in left ventricular ejection fraction.

Left ventricular function in uremia: echocardiographic and radionuclide assessment in patients on maintenance hemodialysis.

Echocardiography and radionuclide ventriculography were performed in 37 uremic patients on maintenance hemodialysis with no apparent coronary artery disease, pericardial effusion, valvular heart disease or heart failure. These non-invasive studies were performed during the interdialytic period (about 18 hours after a dialysis). Sixty-two percent of our patients had abnormal left ventricular function with one or more abnormal echocardiographic parameters. The significant abnormalities were enlargement of the left ventricular cavity, a reduction of myocardial contractility, and thickening of the left ventricular posterior wall. Similar findings were found in 10 undialyzed uremic patients. Measurement of cardiac index and ejection fraction were found to be inadequate for a full assessment of left ventricular function and other parameters such as the mean velocity of circumferential fiber shortening and mean normalized posterior wall velocity should be included. There is a significant number of hemodialysis patients (7/37) with congestive cardiomyopathic features on the echocardiogram. Their clinical features are no different from the other patients in this study, except they have a significantly higher prevalence of uremic hyperparathyroidism. Our findings support that the existence of a specific uremic cardiomyopathy and uremic hyperparathyroidism may play an important role in the pathogenesis.

Gated blood-pool studies of cardiac function in the rat and marmoset.

To develop a sensitive, relatively noninvasive method for monitoring cardiac function in small laboratory animals, equilibrium gated blood-pool imaging (with Tc-99m RBC) was adapted for use in an inbred strain of laboratory rats of 400-470 g body weight and in marmosets of 320-400 g body weight. A 2-mm pinhole collimator was fitted to the gamma camera to produce a distinct image of the left ventricle following intravenous injection of 5 mCi of pertechnetate. Reproducible and consistent data for heart rate, left-ventricular ejection fraction, and peak ejection rate were obtained from studies on 13 male rats and five marmosets maintained on constant diets. An intravenous injection of 0.4 microgram of isoprenaline led to predictable increases in heart rate, left-ventricular ejection fraction, and peak ejection rate, and provided evidence of the sensitivity of the method in monitoring heart function in small laboratory animals.

Detection of synovial cysts by transmission-emission scintigrams following intra-articular 169Yb-DTPA.

A new simple and safe technique for the detection of synovial cysts is described. This investigation employs combined transmission-emission scintigraphy following intra-articular injection of 169Yb-DTPA. Twenty-two joints were investigated in 18 patients. A high degree of correlation was found between clinical findings and the results of this investigation. The major advantages of this method are low local radiation to synovial linings, adequate visualisation of periarticular soft tissue, and small volumes required for intra-articular injection.