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Glucose produced a diphasic pattern of insulin secretion in the perfused rat pancreas. Both phases were blocked by diazoxide. Tolbutamide alone produced a monophasic insulin secretion which was decreased by diazoxide on an equimolar basis. When tolbutamide was added to a perfusion containing glucose and diazoxide, it reversed the blocking effect of diazoxide on glucose by reestablishing the diphasic pattern of glucose-stimulated insulin secretion. This effect was also produced in an equimolar fashion. Leucine induced a diphasic pattern of insulin secretion. When perfused together with glucose, an additive effect was apparent in both phases. Diazoxide blocked the secretion of insulin stimulated by leucine alone or by leucine plus glucose. Arginine (16 mM) failed to stimulate insulin secretion, but a clear increase was observed at 26 mM concentration. An additive effect of arginine and glucose was observed in the presence or absence of 10 mg. per cent diazoxide, but was blocked by increased diazoxide concentration (25 mg. per cent). The results show that the diazoxide effect on the arginine-induced insulin secretion is related to the concentration of diazoxide used, and suggests that the stimulatory action of arginine and glucose is channelled through one identical mechanism, triggering insulin release in the beta cell.

A diazoxide derivative, coded as A044, has been studied in vivo and in vitro and compared to diazoxide in several of its effects. A044 proved to be as hyperglycemic as diazoxide in rats and dogs, but less hypotensive and antidiuretic. It also differs from diazoxide in that it does not modify the basal levels of serum catecholamines. A044 inhibits insulin secretion in the dog in vivo and in the isolated perfused pancreas of the rat in vitro. The latter effect is reversed by an equimolecular dose of tolbutamide. This hyperglycemic compound may prove more useful than diazoxide in the treatment of some hypoglycemic states.

Steady state thermal design of space radiators consisting of flat panel containing parallel single pass tubes

This communication reports studies dealing with the action of glucagon, theophylline, cyclic adenosine monophosphate (3′5′.AMP) and phenoxybenzamine on insulin secretion, and their possible interaction with glucose and diazoxide. Diazoxide inhibited both phases of insulin secretion produced by glucose. This blocking action was suppressed when the alpha-blocking phenoxybenzamine was present. Glucagon produced a uniform pattern of insulin secretion when perfused alone. A one-minute pulse of 3′5′.AMP produced a sharp peak of insulin secretion. Neither glucagon nor 3′5′.AMP effects were inhibited by diazoxide. Theophylline did not increase the basal insulin-secretion. However, when perfused together with glucose, theophylline stimulated additional insulin secretion, significantly higher than that produced by glucose alone. When combinations of glucagon plus glucose, 3′5′.AMP plus glucose and theophylline plus glucose, were perfused, diazoxide blocked the secretion of insulin stimulated by glucose, but not that produced by glucagon, 3′5′.AMP or theophylline. This suggests that glucagon, 3′5′.AMP and theophylline stimulate insulin secretion by actingon mechanismsdifferent from the ones stimulated by glucose

Lopez Rodo L. Le recours de griefs devant le Conseil d'Etat espagnol. In: Revue internationale de droit comparé. Vol. 6 N°1, Janvier-mars 1954. pp. 41-50.

A technic for in situ perfusion of rat pancreas alone or with a small intestine preparation, which is suitable for studying insulin and/or glucagon secretion and the role intestinal factor(s) has upon it, is described. Krebs- Ringer bicarbonate buffer, containing 4.0 per cent bovine albumin and 80 mg. per 100 ml. glucose with pH adjusted to 7.4, was used as perfusate. When the pancreas was perfused with a nonrecirculated buffer there was no significant change in the levels of glucose or insulin in the perfusate, while with recirculated buffer, there was a decrease in both measurements. When additional glucose was added to the perfusate, there was an increase of insulin levels, more marked in the pancreas perfusion with recirculated buffer (possibly pancreatic glucagon plus glucose effect) than in nonrecirculated ones (glucose effect). In pancreas-intestine perfusion with recirculated buffer, there was a decrease of the levels of insulin and glucose, and when additional glucose was added to the perfusate, there was an increase of the levels of insulin and glucose (possibly pancreatic glucagon and glucose effect). When glucose was passed through the intestine, there was a marked increase of the levels of insulin which was significantly higher than the previous group studied, probably due to the effects of glucose, pancreatic glucagon and intestinal factors. It may be possible by the results obtained to separate the effects of the three factors on the release of insulin: glucose, glucagon and intestinal factor(s).

A model of capillary blood flow is studied theoretically by considering the mechanics of a flexible solid object (cell) suspended in a fluid (plasma) flowing in a conduit (capillary). The cell is similar in size to the conduit and deforms in compliance to the fluid stresses. Only axially symmetric systems in two and three dimensions are treated, and several approximations are made in the equations of motion of the plasma and the cell. A nonlinear boundary value problem is thus formulated and is solved numerically over a range of parameter values, including values of physiological interest. The calculations result in parachute-shaped cells whose sides do not touch the conduit wall. When the cell size is approximately equal to the conduit size, the ratio of cell to plasma velocity is 1.67 and the apparent viscosity of the two-phase mixture is 1.05, relative to plasma. These results agree semiquantitatively with experiment.

This paper discusses the operation and performance of the continuous absorption refrigeration system using ammonia and water as the working fluid and being operated by flat-plate solar absorbers. This system has been operating continuously over the greater part of the day producing 2.4 tons of refrigeration with peak loads of 3.7 tons of refrigeration. During steady-state operation the refrigeration effect to the heat input was 0.57. This could be raised to 0.72 with minor system modifications, namely, enlarging the heat exchanger between absorber and generator of the absorption system. Based on operation with auxiliary heat sources this system seems to be able to deliver as much as six tons of refrigeration if enough heat is supplied to the system. This would require the enlargement of the collecting surface from the present 400 square feet to about 1000 square feet. The concentrations used in the system varied from about 58 percent in the absorber to about 39 percent in the generator. Water supply temperatures varied from 140 to 200 degrees F with usual operation at about 175 degrees F.

ResumeNous rendons compte de la presence d'Albugo candida (Pers.) Ktze. sur Cochlearia aragonensis Coste & Soulie, a la Sierra de Satrustegui (Huarte-Araquil, Navarra), Espana.

Fluck, D. C., Lopez Bescos, L., and Gilkes, R. (1973).Thorax,28, 762-767. Effect on blood volume of maintaining a high central venous pressure after major aortic valve surgery. Serial blood volume measurements were made in 15 patients undergoing major aortic valve surgery requiring cardiopulmonary bypass. In all patients the plasma volume was measured by iodine-125 (125I) labelled albumin and in 10 the red cell mass was measured by chromium-51 (51Cr) labelled red cells. Close correlation was found between the blood volume derived from the plasma volume and central venous haematocrits and the blood volume derived by addition of the plasma volume and red cell mass. Postoperatively blood was given to maintain the right atrial pressure at between 10 and 15 cm H2O. Before operation the red cell mass, and plasma and blood volumes related to body weight were within the normal range. In the postoperative phase the first measurement two hours after the end of the operation showed a significant decrease in mean blood volume, red cell mass, and plasma volume as compared with the preoperative level. By the second postoperative measurement six hours after the end of operation the mean blood volume had risen to the preoperative level. Subsequently, over postoperative days 1 to 6 the mean blood volume remained steady, although the red cell mass tended to fall. After blood transfusion had ceased the red cell mass usually showed a progressive fall. It was considered that although there was little relationship between the right atrial pressure and the blood volume there was little or no clinical value in performing serial postoperative measurements of blood volume in addition to venous pressure monitoring in these patients.

The movement of the anterior leaflet of the mitral valve has been recorded with an ultrasound echo technique. The intrinsic mobility of the valve cusps and the rate of ventricular filling are thought to influence the closure of the valve during diastole. Atrial contraction occurs at the end of ventricular diastole and reopens the valve before the mitral valve returns to the closed position before the onset of ventricular systole. The relation of the opening snap and third heart sound to the movement of the cusp is shown. In mitral stenosis ventricular systole occurs when the mitral valve is still far away from the closed position and the rapid movement of the cusp to the closed position may be the cause of the high intensity vibrations of the first heart sound. The EF slope (representing the rate of the closing movement of the cusp in end diastole) is decreased and a good correlation has been found with the degree of stenosis. After mitral valvotomy the EF slope increases significantly. The validity of these methods in assessing mitral incompetence or relative predominance of stenosis or incompetence in mixed mitral lesions is discussed. The ultrasound cardiograph is a fairly simple and completely atraumatic technique with proven diagnostic value in mitral valve disease. In addition, because of the new type of information that is given, it has potential as a research tool which is, as yet, largely unexplored.