Expression of alpha-D-mannosidase in man-hamster somatic cell hybrids

Two types of alpha-D-mannosidase isozymes are present in human white blood cells, human diploid fibroblasts, and HeLa cells. One of these (the S isozyme) constitutes the major alpha-D-mannosidase of the human cells, has a pH optimum of 4.4, and is associated with lysosomes. The other (the F isozyme) is most active at pH 6, is acid labile, and is located in the soluble portion of the cytoplasm. The expression of human lysosomal alpha-D-mannosidase was examined in man-hamster hybrid clones, and was found to be concordant with that of phosphohexose isomerase in 54 of 55 primary clones. A locus specifying human lysosomal alpha-D-mannosidase has therfore been assigned to chromosome 19.     

Drug exposure and the acquisition and retention of a conditioned taste aversion

Two experiments examined the effects of preexposure and postexposure to a drug on the acquisition and retention of a conditioned taste aversion induced by that drug. Experiment 1 demonstrated that although drug preexposure attenuated a subsequent conditioned aversion, repeated taste-drug pairings reversed the initial attenuation effect and resulted in nearly complete avoidance of consumption. Experiment 2, however, demonstrated that drug postexposure did not alter a previously established conditioned aversion, although the postexposure experiences were effective in attenuating a conditioned aversion to a second novel solution. It was suggested that conditioned aversions are mediated by ACTH and that preexposure to a drug results in tolerance to that drug, yielding a smaller ACTH response and thereby a weaker aversion.     

Histochemical study of sodium nucleinate-activated peritoneal macrophages

The activity of various enzyme groups and the levels of protein and glycogen in the peritoneal macrophages of CBA mice treated intraperitoneally with sodium nucleinate were determined histochemically with the use of cytophotometry. A significant increase in the activity of the lysosomal enzymes, such as acid phosphatase and nonspecific esterases and an increase in the activity of lactate, malate, glutamate, alpha-glycerophosphate, and beta-hydroxybutyrate dehydrogenases. NAD.H- and NADF.H-diaphorases accompanied by an increase in the level of the total protein and glycogen were observed. Analysis of the changes was indicative of an increase in the inherent physiological metabolic and functional level under the effect of sodium nucleinate. It is suggested that the macrophage sub-populations with an increased metabolic activity appeared in the peritoneal exudate of the stimulated animals. Participation of the host low molecular DNA in the maintenance of the physiological level of th nonspecific antiinfectious resistance is suggested.     

The cytogenetic disorders in the people who took part in the cleanup of the sequelae at the Chernobyl Atomic Electric Power Station and who lived continuously in areas with an unfavorable ecological situation

Cytogenetic disturbances are manifested now in persons who liquidated aftereffects of the Chernobyl disaster. The character and course of the disturbances depend on the ecological conditions of the region where liquidators live at present. Examination of a group of liquidators with nerve-psychopathologic disorders and accompanying somatic pathology has revealed the presence of cytogenetic disturbances, mainly of the chromosome aberration type. At the same time, in persons who live under conditions of high environment pollution with ejections of industrial enterprises, the number of chromatid aberrations increases, which may be a result of action of chemical mutagens. A tight correlation is revealed between the level of cytogenetic disorders in lymphocytes and expressivity of the secondary immunodeficiency. Elimination of lymphocytes with unstable chromosome aberration is delayed when ecological pollution of the biosphere reaches the high level.     

Toxic effect of systemic administration of low doses of the plasticizer di-(2-ethyl hexyl) phthalate [DEHP] in rats

A spreadsheet model of a circle breathing system and a 70-kg anaesthetised 'standard man' has been used to simulate the first 20 min of low-flow anaesthesia with halothane, enflurane, isoflurane, sevoflurane and desflurane in oxygen. It is shown that, with the fresh-gas flow set initially equal to the total ventilation and the fresh-gas partial pressure to 3 MAC, the end-expired partial pressure can be raised to 1 MAC in 1 min with desflurane and sevoflurane, 1.5 min with isoflurane, 2.5 min with enflurane and 4 min with halothane. Sequences of lower fresh-gas flow and partial pressure settings are given for then maintaining 1 MAC end-expired partial pressure, with a minimum usage of anaesthetic, e.g. 13 ml of liquid desflurane in 20 min (of which only 33% is taken up by the patient) if the minimum acceptable flow is 11.min-1, or 8 ml (with 57% in the patient) if the minimum is 250 ml.min-1.