Hearing loss with frequent diving (deaf divers).

An audiometric survey was performed on a group of professional abalone divers, all of whom had experienced a great deal of exposure to dysbaric conditions. The results of this survey revealed that, even allowing for the very liberal requirements of the Australian standards for divers, over 60% had an unacceptable sensorineural, high frequency deafness. In half of these cases it was unilateral, and half bilateral.

Total body potassium and water, and exchangeable sodium, in muscular dystrophy.

Total body potassium (40K method) and total body water and exchangeable sodium (both by isotope dilution) were determined in 26 boys, aged 5-17 years, with muscular dystrophy. Total body potassium values were compared with measurements in a large series of normal boys on the basis of height. Total body potassium was reduced even in the youngest patients and was only slightly higher in the older boys, despite their considerably greater height.

Receptors for thyroid-stimulating hormone in normal and pathological human thyroid tissues.

The receptors for TSH have been studied in human thyroid tissue to assess their density and binding characteristics in various disease states. A single set of similar independent receptors appeared to be present in both healthy and pathological thyroid tissue. Their binding affinity for bovine TSH averaged 1.

Amiloride sensitive and insensitive sodium pathways and the cellular sodium transport pool of colonic epithelium in rats.

Methods for measurement of the epithelial Na transport pool (Nat) using epithelial scrapings and for analysing the transepithelial ionic fluxes of rat distal colon in vivo into transcellular and paracellular components have been used to study the amiloride sensitive (a.s.) and amiloride insensitive (a.

Microvascular permeability in induced astrocytomas and peritumor neuropil of rat brain. A high-voltage electron microscope-protein tracer study.

Brain tumors, benign and malignant, are characteristically more permeable to various types of tracer molecules than the neuropil in which they are embedded. Impermeability of brain neuropil capillaries is imparted by the blood-brain barrier, the anatomic basis of which is the network of interendothelial zonulae occludentes that seal capillary endothelial cells. To explore both the vascular elements of brain neoplasms and the route of tracer extravasation from them, as well as the possible effects of brain tumors on the permeability of peritumoral neuropil capillaries, brain tumors were induced in newborn Wistar rats by intracerebral (i.

Absorption and secretion of fluid and electrolytes by the rectum.

Although the amounts of ions and water absorbed and secreted by the rectum are small compared to those of other parts of the colon, rectal epithelium is capable of generating and maintaining considerable ionic gradients. Absorption of Na+ and Cl- and secretion of K+ and HCO-3 leads to relatively low concentrations of the former and high concentrations of the latter within the lumen. Detailed examination of the transport processes indicates that the epithelial mechanisms can be interpreted in terms of ionic movements through transcellular and paracellular pathways.

Anion transport in the colon.

The principal anions transported by colonic epithelium are Cl-, HCO3- and organic anions (OA-), particularly acetate, butyrate and pyruvate, these last being formed by microbial degradation of carbohydrate. In the normal absorptive rat colon, Cl- is transported from lumen to plasma both by the transcellular and paracellular pathways. The transcellular route appears to depend on amiloride-insensitive coupling of Na+-Cl- at the mucosal (apical) membrane, the Na+ electrochemical gradient energizing Cl- uptake.

Transfer effects in feature-positive and feature-negative learning by adult humans.

In two experiments, college students performed a feature-positive or a feature-negative discrimination task based on colors or symbols and were then transferred to a feature-positive or feature-negative discrimination based on the other stimulus dimension (symbols-colors, colors-symbols). Initial task results yielded a substantial feature-positive effect and indicated that the color task was easier than the symbol task. Transfer task results indicated that the feature-positive effect was maintained and showed that consistent transfer (positive-positive, negative-negative) led to superior performance on the transfer task.

Autoantibodies to thyroglobulin cross reacting with iodothyronines.

Serum thyroxine was consistently unmeasurable by radioimmunoassay in an elderly patient with myxoedema after successful treatment with oral thyroxine. Abnormal binding of thyroxine was suspected and shown to be due to the presence in serum of antibodies of the IgG variety. The characteristics of these antibodies with respect to their binding of thyroxine (T4), triiodothyronine (T3), reverse triiodothyronine (rT3) and human thyroglobulin (Tg) were systematically studied.

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.

Comparison of binding of bovine and human thyroid-stimulating hormone to receptor sites on human thyroid membranes.

The binding of 125I-labelled bovine TSH (bTSH) to a wide range of human thyroid membrane preparations was compared with that of 125I-labelled human TSH (hTSH). Much higher binding percentages were obtained with the 125I-labelled bTSH. This was because the receptors had a higher binding affinity for bTSH than for hTSH.

Amiloride sensitivity of the transepithelial electrical potential and of sodium and potassium transport in rat distal colon in vivo.

1. The effect of amiloride within the gut lumen on the transepithelial electrical potential difference (p.d.

Pathways of transepithelial potassium movement in the epithelium of distal colon in man.

1. Methods for studying the kinetics of movement of radioactive tracers across human distal colonic epithelium have been developed for use in vivo and applied to examination of transepithelial transfers of potassium. 2.

Absorption by the colon during prolonged infusions in conscious, unrestrained rats.

1. Colonic absorption was studied in conscious, unrestrained rats during prolonged infusions through implanted cannulae. During infusion of predominantly NaCl-containing solution at rates up to 0.

Methods and problems in the measurement of body water and electrolyte pools with radionuclide tracers.

With the possible exception of ECF, body electrolyte spaces and pools can be measured with fair accuracy and are useful in their proper experimental context. The use of improved tracer techniques and mathematical analysis to study transfer rates between pools and the physiological factors which influence these rates offer a promising means of further progress in this field.

Changes in fat, fat-free mass and body water in human normal pregnancy.

Measurements of body weight, total body water and total body potassium (40K) were made serially on three occasions during pregnancy and once post partum in 27 normal pregnant women. Skinfold thickness and fat cell diameter were also measured. A model of body composition was formulated to permit the estimation of changes in fat, lean tissue and water content of the maternal body.

Epithelial transport pathways of rat colon determined in vivo by impulse response analysis.

1. A method is described for studying transepithelial pathways for the movement of different solutes and water. Using the blood and the secretory curves of changing tracer activity following an intravenous bolus, the rate of transit of molecules together with their impulse response functions, which reflect the transfer processes can be examined.

CLINICAL TRIALS OF THE ABDOMINAL LEFT VENTRICULAR ASSIST DEVICE (ALVAD): PROGRESS REPORT.

An abdominal left ventricular assist device (ALVAD) is undergoing controlled clinical trials in our institution. The ALVAD is pneumatically-actuated, synchronously or asynchronously with an external console and is interposed between the apex of the left ventricle and the infrarenal abdominal aorta. It is an order of magnitude more effective than conventional intraaortic balloon pumping.

RIGHT AND LEFT VENTRICULAR HEMODYNAMIC INDICES AS PREDICTORS OF THE NEED FOR AND OUTCOME OF POST-CARDIOTOMY MECHANICAL INTRAAORTIC BALLOON PUMP SUPPORT.

Preoperative cardiac catheterization data of 21 patients requiring intraaortic balloon pumping (IABP) for weaning from cardiopulmonary bypass were analyzed and compared with similar data in 28 patients who underwent nearly similar operative procedures, but did not require IABP for weaning. Cardiac index (CI) and systemic vascular resistance (SVR) were found to have predictive value for the need of IABP for weaning from cardiopulmonary bypass and differentiated survival from non-survival. Left ventricular end diastolic pressure (LVEDP) was not found to be predictive.