Biomedical subjects
Publications and source records attributed to K Juhl.
The development and potential of a catalytic enantioselective Henry reaction of nitromethane with various alpha-keto esters catalyzed by chiral bisoxazoline-copper(II) complexes are presented.
Capacitance measurements were used to investigate the molecular mechanisms by which imidazoline compounds inhibit glucagon release in rat pancreatic alpha-cells. The imidazoline compound phentolamine reversibly decreased depolarization-evoked exocytosis >80% without affecting the whole-cell Ca(2+) current. During intracellular application through the recording pipette, phentolamine produced a concentration-dependent decrease in the rate of exocytosis (IC(50) = 9.7 microm). Another imidazoline compound, RX871024, exhibited similar effects on exocytosis (IC(50) = 13 microm). These actions were dependent on activation of pertussis toxin-sensitive G(i2) proteins but were not associated with stimulation of ATP-sensitive K(+) channels or adenylate cyclase activity. The inhibitory effect of phentolamine on exocytosis resulted from activation of the protein phosphatase calcineurin and was abolished by cyclosporin A and deltamethrin. Exocytosis was not affected by intracellular application of specific alpha(2), I(1), and I(2) ligands. Phentolamine reduced glucagon release (IC(50) = 1.2 microm) from intact islets by 40%, an effect abolished by pertussis toxin, cyclosporin A, and deltamethrin. These data suggest that imidazoline compounds inhibit glucagon secretion via G(i2)-dependent activation of calcineurin in the pancreatic alpha-cell. The imidazoline binding site is likely to be localized intracellularly and probably closely associated with the secretory granules.
The development of a direct catalytic asymmetric Mannich reaction is shown and its potential demonstrated by the synthesis of optically active lactones via 4-hydroxyglutamic acid ester derivatives. The catalytic asymmetric Mannich reaction of carbonyl compounds with α-imino esters [Eq. (1); Ts = p-toluenesulfonyl] gives good yields and diastereoselectivities, as well as excellent enantioselectivities.
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This study investigates the impact of AIDS at the workplace for various occupational fields. Additionally, employees' interest in AIDS-related information and education is studied. 448 employees in Hamburg completed a questionnaire on these issues. The results show marked differences between medical staff and all other occupational fields. Implications for the organization of information and education are discussed.
The relevance of the attitude toward the HIV test, the subjectively perceived infection risk, the expected consequences of testing, and the perceived reference group influences for HIV antibody testing is studied. 211 persons, who were tested for AIDS in an AIDS consulting institution, and 86 controls, who had not been tested, participated in the study. The significance of the results for AIDS prevention is discussed.
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