Biomedical subjects
Publications and source records attributed to H Dietrich.
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A series of 1-[[p-[2-(acylamino)ethyl]phenyl]sulfonyl]-2-iminoimidazolidines has been synthesized. Compounds from this new class of oral hypoglycemic agents lower blood glucose in normal and in streptozotocin-diabetic rats. Potent analogues were obtained by modification of the acyl residue. 1-[[p-[2-(Crotonylamino)ethyl]phenyl]-sulfonyl]-3-cyclohexyl-2-iminoimidazolidine (44) turned out to be the most potent compound in the normal rat (20 times tolbutamide), and 1-[[p-[2-(5-methylisoxazole-3-carboxamido)ethyl]phenyl]sulfonyl]-3-cyclohexyl-2-imino-imidazolidine (30) displayed the highest potency in the diabetic rat (similar to phenformin).
The positive visual phenomena of palinopsia and cerebral diplopia/polyopia have only rarely been recorded. The complex phenomenology (visual/oculomotor) is described based on two cases with right occipital infarcts and a review of the literature. In each case demonstrated CT revealed a small area of decreased density confined to the border region of the right area striata causing homonymous field defects. The phenomena are discussed in the light of what is known about visual after-images and hallucinations. The underlying neural mechanisms are still unknown; a defective cortical visual information processing is suggested.
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The visible absorption bands in the region 525-575 nm of the catalytic cobalt ion in cobalt(II) horse liver alcohol dehydrogenase show characteristic pH-dependent changes both in the free enzyme and its complexes with nicotinamide adenine dinucleotide (NAD+) and NAD+ plus ethanol or 2,2,2-trifluoroethanol. In the free enzyme, the change of the coordination environment has an apparent pK of about 9.4. In the binary complex with NAD+ the spectral changes are complex, indicating changes in the coordination sphere in a lower pH range with an estimated pK value of about 7.9. The ternary complexes enzyme X NAD+ X ethanol and enzyme X NAD+ X 2,2,2-trifluoroethanol exhibit very similar, characteristic spectral features; their apparent pK values are 6.3 and less than 4, respectively. We ascribe these pK values to the ionization of the alcohol bound in the ternary complexes. The results demonstrate that the catalytic cobalt ion is sensing changes of the ionization state of the protein when going from low pH forms to high pH forms both in the absence and presence of coenzyme and substrate/inhibitor.
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Whereas the numerous psychotherapy schools in the Freud tradition seem slightly ephemeral from the historical point of view, and whereas the intramural and extramural advocates of the philosophical, psychological psychosomatic and purely scientific aspects of psychiatry wage a constant war of competition for the recognition of their special fields and expansion of their power over others, Kraepelin's teaching, whose spirit has already survived two generations of psychiatrists, is even gaining recognition and power of persuasion. It is therefore termed orthodox, the others schismatic. The combination of an empirical phenomenology of psychiatric diseases with their biological roots places Kraepelin's psychiatry on a sure foundation which makes possible convention, uniform assessment of homologous cases, legal security in giving expert opinions and the clinical framework for experimental research.
Insertion of nickel ions into the empty catalytic site of horse liver alcohol dehydrogenase yields an active enzyme with 65% metal substitution and about 12% intrinsic activity. The electronic absorption spectrum is characterized by bands at 357 nm (2900 M-1 cm-1), 407 nm (3500 M-1 cm-1), 505 nm (300 M-1 cm-1), 570 nm (approximately equal to 130 M-1 cm-1), and 680 nm (approximately equal to 80 M-1 cm-1). The absorption and CD spectra are similar to those of nickel(II) azurin and nickel(II) aspartate transcarbamoylase and prove coordination of the nickel(II) ions to sulfur in a distorted tetrahedral coordination geometry. Changes of the spectra upon ligand binding at the metal or conformation changes of the protein induced by coenzyme, or both, indicate alterations of the metal geometry. The chromophoric substrate trans-4-(N, N-dimethylamino)-cinnamaldehyde forms a ternary complex with Ni(II) liver alcohol dehydrogenase and the coenzyme analogue 1,4,5,6-tetrahydronicotinamide-adenine-dinucleotide, stable between pH 6 and 10. The corresponding ternary complex with NADH is only stable at pH greater than 9.0. The spectral redshifts induced in the substrate are 11 nm larger than those found in the zinc enzyme. We suggest direct coordination of the substrate to the catalytic metal on which acts as a Lewis acid in both substrate coordination and catalysis.
Insertion of Cu2+ ions into horse liver alcohol dehydrogenase depleted of its catalytic Zn2+ ions creates an artificial blue copper center similar to that of plastocyanin and similar copper proteins. The esr spectrum of a frozen solution and the optical spectra at 296 and 77 K are reported, together with the corresponding data for binary and ternary complexes with NAD+ and pyrazole. The binary complex of the cupric enzyme with pyrazole establishes a novel type of copper proteins having the optical characteristics of Type 1 and the esr parameters of Type 2 Cu2+. Ternary complex formation with NAD+ converts the Cu2+ ion to a Type 1 center. By an intramolecular redox reaction the cuprous enzyme is formed from the cupric enzyme. Whereas the activity of the cupric alcohol dehydrogenase is difficult to assess (0.5%-1% that of the native enzyme), the cuprous enzyme is distinctly active (8% of the native enzyme). The implications of these findings are discussed in view of the coordination of the metal in native copper proteins.
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The specific substitution, using highly selective techniques, of catalytic and/or noncatalytic zinc ions by cobaltous ions in horse liver alcohol dehydrogenase (EC 1.1.1.1) has been studied with dissolved, crystalline and agarose-immobilised enzyme, in order to examine the effect of protein structure on the specificity of the metal exchange. The different binding sites can be clearly distinguished by the absorption spectra of their cobalt derivatives. In solution an anaerobic column chromatographic method made it possible to exchange half of the zinc in the enzyme by cobalt ions in a much shorter time than previous procedures. By raising the temperature in the exchange step, even the slowly exchanging zinc ions were substituted by cobalt, yielding products similar to cobalt alcohol dehydrogenases described earlier. Treatment of crystal suspensions of the enzyme with chelating agents (preferentially dipicolinic acid) gave an inactive protein with two zinc ions remaining bound. The enzyme could be reactivated by treatment of the crystalline protein with 5 mM zinc or cobaltous ions or by dialysis of dissolved inactive protein against 20 microM zinc or 1 mM cobaltous ions. Higher metal concentrations led to denaturation but the inactive protein could be crystallized from solution and then reactivated completely at higher metal concentrations. The preparation and absorption spectrum show that cobalt is bound specifically at the catalytic sites. Since metal substitution at these sites critically depends on the maintenance of the correct tertiary and quaternary structure, these must be preserved in the crystal lattice and partially altered in solution when the catalytic zinc ions are removed (or when excess of metal ions is applied), thus demonstrating the structure-stabilizing role of the catalytic metal ions. The enzyme immobilised on agarose, with unchanged content of active sites [Schneider-Bernlöhr et al. (1978) Eur. J. Biochem. 41, 475--484], was treated like the crystal suspensions. Although half of the zinc was removed, some activity remained. After reactivation with cobaltous ions, a loss of about 30% active sites was measured. Thus the apparently homogenous bound enzyme was rather heterogeneous in the properties of its catalytic metal binding sites. These results are taken as further proof for the dependence of the metal substitution on the proper tertiary and quaternary structure which is strained by multiple interactions in the covalently immobilised enzyme.
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A case of superfetation is reported. A 23 year old gravida 3, para 1, aborta 1 had a D & C and partial left salpingectomy for ruptured left tubal pregnancy. The microscopic examination of the curettings and the left fallopian tube revealed two pregnancies. The tubal pregnancy was obviously older than the intra-uterine pregnancy and the two fertilized eggs had to result from different ovulations.
Unlike the other five deadly sins of the Church, sloth is not attributed to an instinct or an impulse but to an anancastic form of reaction. A phlegmatic person is characterised by a lack of egoistic or altruistic instincts while feelings of nausea or fear are increased. Among phlegmatic persons those of clinical importance are epileptoid psychopaths, oblomovists and those exhibiting (forms of) phlegmatic temperament combined with obsessional or hysterical neurosis.
1. Spectroscopic methods for protein and active-site determination with the same sample of immobilised horse liver alcohol dehydrogenase have been developed. 2. The influence of pH, active-site protection of the soluble enzyme and protein concentration on coupling of alcohol dehydrogenase with cyanogen-bromide-activated Sepharose has been investigated. In phosphate buffer (pH 8.0) products with over 90% active-site retention have been synthesized. The binary complex alcohol-dehydrogenase . NADH gives a preparation with the same active-site content but a lower apparent specific activity compared to the unprotected enzyme. Increase in protein concentration yields products with the same active-site content relative to bound protein but the apparent specific activity is decreased. 3. The great similarity in spectroscopic properties of soluble and immobilised enzyme, as well as of their ternary complexes, shows that no significant conformational change has taken place during immobilisation. 4. Exchange of the non-catalytic Zn2+ against Co2+ yields a hybrid Sepharose--Co2Zn2-alcohol-dehydrogenase with over 90% active-site retention during metal exchange. The absorption spectra of the soluble and immobilised hybrid are identical.
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Intuition in the medical diagnostic sphere is a subconscious cognitive act, the result of which appears consciously as a flash of imagination. Scientific intuition presumes expert knowledge and works consciously with the mnemic reservoir and the associative forces from the subconscious. Low degrees of a hysterical and paranoic nature facilitate access to the subconscious and projection. Intuitive knowledge is corrected by rational thinking.