Segmental renin sampling and partial nephrectomy in renal hypertension

Selective renin sampling from renal vein tributaries identified a high-renin source in the lower pole of the left kidney in a 16-year-old boy who had gradually developed hypertension after blunt left renal trauma. Localized renin secretion from the ischemic pole was associated with suppression of renin secretion from both the contralateral kidney and the normal part of the affected kidney. Removal of ischemic tissue by partial nephrectomy produced sustained correction of hypertension. The findings indicate that segmental renin sampling can define indications for partial nephrectomy in renal hypertension.     

Swelling Control in Uranium Carbide

Fine particles were dispersed in a fuel structure to trap fission gases as very small bubbles and thereby reduce fuel swelling. The dispersions were made by adding 1.5 to 3.0 wt% W to the UC; the specimens were irradiated to a maximum of ∼2 at.% burnup. Density changes were used as the measure of swelling; there was much scatter in the results. Tungsten reduced the swelling when it was uniformly dispersed. For some samples having excess U and W or a segregated structure, W increased the swelling. The results tentatively confirm that fine particles are of value in reducing fission-gas swelling of carbide fuels.     

Effect of dehydration on stimulation of ADH release by heterologous renin infusions in conscious dogs

The effect of acute administration of morphine on cerebral excitability was investigated in rats with two convulsant drugs: flurothyl (hexafluorodiethyl ether) and pentylenetetrazol (PTZ). In the flurothyl study, adult male Sprague-Dawley (S-D) rats were injected subcutaneously with morphine sulfate in doses ranging from 0.5 to 256 mg/kg. At 15, 30, 60 and 120 minutes after morphine injection, flurothyl was administered by inhalation and the seizure thresholds were determined. In the PTZ study, 64 mg/kg of morphine sulfate were injected subcutaneously into both S-D and CFN (Wistar-derived) rats. Thresholds to PTZ seizures were measured after administering the convulsant either by the intraperitoneal or intravenous route. The data revealed an anticonvulsant action of morphine on both flurothyl and PTZ. Peak time for this effect on flurothyl seizures was 30 minutes after subcutaneous administration of the opiate, with the maximal anticonvulsant activity appearing at the 64-mg/kg dose. The increase in seizure threshold in S-D rats at this dose was 36% with flurothyl, 94% with intravenous PTZ and 352% with i.p. PTZ. Morphine had a less dramatic influence on raising the latter seizure threshold in the CFN than in the S-D strain. The graded dose-related anticonvulsant action is independent of the respiratory depression associated with morphine administration and appears to be a reflection of an altered central nervous system excitability produced by the narcotic in rats.     

Net Present Value from Complex Cash Flow Streams by Simulation

In models previously developed for the purpose of obtaining net present value from a stream of discounted cash flow increments, it is difficult to introduce complex economic, market and behavioral considerations without rendering the problem intractable computationally. Monte Carlo simulation with a digital computer, particularly in a simulation language, offers an attractive and feasible solution to the flexibility problem. This article illustrates the use of simulation techniques to find the net present value of a proposed project, together with its statistical distribution, when three types of phenomena are incorporated in the model: (1) long-term exponential market growth, (2) “non-instantaneous” response by the firm to price/elasticity fluctuations, and (3) imposition of arbitrary, yet reasonable, constraints on product output.     

Dihydrofolate reductase and thymidylate synthetase activities in the liver of rabbit foetuses during the haemapoietic period

Dihydrofolate reductase activity did not change with variations of mitotic rate in foetal rabbit haemopoietic tissue, whereas the activity of thymidylate synthetase declined with decrease in cell divisions. Both the activities were normal in the brachydactylia strain, in which a failure in folate metabolism was previously assumed.