The Prevention of Acute Tubular Necrosis in Renal Transplantation by Chronic Salt Loading of the Recipient1

By replacing normal water intake with 0–9% saline solution on a continuing basis, animals are protected against acute is ch?mic tubular necrosis. Last-minute plasma volume expansion does not provide this protection. To see whether the protection is intrinsic to the kidney or merely involves the host, kidneys were transplanted syngeneically from salt-drinking rats to water-drinking rats, and vice versa, and the recipients were injected with glycerol to produce myoh?moglobinuric renal failure. The kidneys transplanted from water-drinking animals did not develop failure in the salt-drinking animals, but those from salt drinkers did develop failure in the water drinkers. Therefore overhydration of the recipient by continuous salt loading is important in preventing acute tubular necrosis in renal transplantation.     

The effects of dexamphetamine on simulated driving performance

Rationale The number of road fatalities related to the presence of amphetamines in drivers has been relatively constant over the past 10 years. However, there remains uncertainty as to the extent that these drugs induce driving impairment, and whether any such impairments translate to an increase in road fatalities.Objectives To examine the acute effects of 0.42 mg/kg dexamphetamine on simulated driving performance, and to establish which, if any, simulated driving abilities become impaired following dexamphetamine administration.Methods A repeated-measures, counter-balanced, double-blind, placebo-controlled design was employed. Twenty healthy volunteers completed two treatment conditions—0.42 mg/kg dexamphetamine and placebo. Performance was assessed using a driving simulator task. Blood and saliva samples were obtained prior to the driving tasks and immediately after task completion (120 min and 170 min post-drug administration, respectively).Results Mean dexamphetamine blood concentrations were 83 ng/ml and 98 ng/ml at 120 min and 170 min, respectively. Results indicated a decrease in overall simulated driving ability following dexamphetamine administration during the day-time but not the night-time scenario tasks. Contributing to this performance reduction, incorrect signalling, failing to stop at a red traffic light and slow reaction times were the behaviours most strongly affected by dexamphetamine.Conclusions The decrease in simulated driving ability observed during the day-time driving tasks are consistent with the perceptual narrowing or tunnel vision that is associated with dexamphetamine consumption.     

Non-thiol farnesyltransferase inhibitors: N-(4-aminoacylamino-3-benzoylphenyl)-3-[5-(4-nitrophenyl)-2 furyl]acrylic acid amides and their antimalarial activity

Water solubility was previously found to be essential for in vivo-antimalarial activity of a novel type of benzophenone-based farnesyltransferase inhibitors. Introduction of a alpha-amino group into the phenylacetic acid substructure provided more soluble compounds with high farnesyltransferase inhibitory activity. The in vitro-antimalarial activity was detrimentally influenced by this structural modification.     

Compensatory and Obligatory Renal Growth in Babies and Adults1

On the basis of previous studies in rats, and clinical observations in human renal transplantation and in patients with a renal duplication anomaly, we have postulated two distinct types of renal growth. Compensatory growth is caused by a nephron deficit, while obligatory growth is part of the normal process of growing into adulthood. The former is reversible, and the latter is not. A definitive test of this hypothesis required the transplantation of extra kidneys into baby rats and comparison of their growth with that of normal litter-mate controls. This showed that there is little if any retardation of obligatory renal growth in spite of the presence of an excess of kidneys in the baby.     

Properties of lymphocyte 5'nucleotidase in normal subjects and patients with chronic lymphocytic leukemia

Heterogeneity for 5'nucleotidase has been demonstrated in chronic lymphocytic leukemia [12]. The enzyme is not detectable in the lymphocytes from the majority of patients with this disorder, but normal and even supranormal levels are found in some cases [17]. In the present studies, the properties of this ecto-nucleotidase were investigated in unhomogenized lymphocytes isolated from the blood of normal subjects and patients with chronic lymphocytic leukemia. The activity was found to have a pH optimum of 8.0-8.5 and a preference of 5'ribo- over 5'deoxyribonucleotides. The enzyme was inactive towards 2',3'AMP. The Km for AMP showed a broad range from 19 to 210 microM in unhomogenized lymphocytes. An unexpected relationship was observed between sp. act. and this Km in that higher Km values were noted with cells from subjects with high lymphocyte 5'nucleotidase sp. act. and low Km values in lymphocyte preparations with low sp. act. When plasma membranes were prepared, a narrow range of low Km values unrelated to sp. act. was noted. The change in Km was not due to Pi concentration or nucleotide effects. The ecto-enzyme was inhibited by alpha, beta-methylene adenosine diphosphate, while cytosol phosphatase activity was not inhibited by this compound. Heat stability studies revealed a 45% loss in 5'nucleotidase activity after incubation for 20 min at 65 degrees C. A comparison of the substrate preference, Km values, effect of inhibitor and subcellular localization revealed no differences between the enzyme from patients with chronic lymphocytic leukemia and from normal subjects. This finding is consistent with the suggestion that the undetectable or supranormal levels observed in the lymphocytes of patients with this disorder stems from variations in the percentage of cells having 5'nucleotidase rather than changes in the enzyme proper.     

Anorexia nervosa in black adolescents

Anorexia nervosa has been considered rare or nonexistent among blacks. A report of the presentation and clinical course of this disorder in two black female adolescents illustrates a serious medical psychiatric problem that may be increasingly detected among predisposed teenagers of the black middle and professional classes. Unrecognized and incorrectly treated, the disease may run a fatal course in 20 percent of the cases. Differential diagnosis, etiology, and treatment of the condition are reviewed.     

Physicochemical and morphological characterization of a new allotransplantable mammary carcinoma ascites subline, TA3-St/ticol/-A

The TA3-St/ticol ascites cell (I), immunoselected from the strain-specific TA3-St mammary carcinoma ascites cell of the strain A mouse for decreased H-2a antibody-binding capacity, underwent a spontaneous transition in vivo to a new cell line, TA3-St/ticol/-A (II). Line II was more allotransplantable than was the parental line (line I), and its absorptive capacity for anti-H-2a antibody was manyfold less than line I. Disruption of line II cells by lyophilization did not increase the absorptive capacity, in contrast to its marked enhancement in the TA3-Ha ascites cell under similar conditions. An explanation for the enhanced allotransplantability of line II may be related to either a loss of H-2a antigens or altered macromolecular structures at the cell surface: sialic acid, consisting of 93% N-glycolylneuraminic acid for line II and 9% for line I; altered chemical structures of cell surface glycoproteins, particularly a high-molecular-weight glycoprotein present in much greater proportion in line II than in line I; a macromolecular complex released by a protease from line I, but not line II; and I being agglutinable by concanavalin A, but not line II. Electron microscopy showed line II to be more pleomorphic and less rounded than was line I. Under high-resolution electron microscopy, the cell surfaces of both allotransplantable cells, lines II and I, exhibited thin filamentous material, material not observed at the surface of the nonallotransplantable TA3-St ascites cell.