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Biomedical subjects

H Horn

Publications and source records attributed to H Horn.

At least 55 records · Page 3Linked to original sources
PubMed1988

[Synthetic inhibitors of serine proteinases. 34. The effect of modification of the amidino function of N-alpha-substituted 4-amidinophenylalanine amides on inhibitory activity].

Cyclic amides of N alpha-arylsulfonylated 4-amidinophenylalanine are selective inhibitors of thrombin. The exchange of the amidino function for an aminomethyl residue does not influence the selectivity and potency of their inhibitory activity. In contrast, the modification of the amidino function of the N alpha-arylsulfonylaminoacylated compound N alpha-(2-naphthylsulfonylglycyl)-4-amidinophenylalanine piperidide results in a drastic loss of inhibitory activity. Only the oxamidino derivative possesses considerable high affinity for thrombin. Obviously, in tight binding inhibitors of thrombin structural variation results in any case in a loss of inhibitory activity.

Amidines↗
PubMed1988

[Prospective one-year epidemiologic longitudinal study of air pollutants and the incidence of croup].

Among a population of 18,175 children below 7 years of age in medium sized towns and rural areas in south-western Germany 552 (3.03%) cases of croup were registered during a 12 months period in 1984-85 by their physicians. Distributions according to months, sex and age at the onset of the disease were the same as in other recent investigations: The level of the air-pollution measured (SO2, NOx, CO, CO2, ozone and dust) was low (highest monthly means in microgram/m3: SO2 88, NO2 73, NO 119, dust 41). There was no relevant influence of the degree of air pollution on croup-frequency. The rise of croup-frequency shortly after a period of several days of higher pollution was accompanied by an influenza epidemic as proved by virus isolations.

Air Pollutants↗
PubMed1987

[Prostaglandin synthesis in stomach and duodenal mucosa of the human: effect of aspirin with and without antacid].

A decreased PG E2 content in gastric mucosa of humans receiving a longterm antirheumatic therapy has been reported to be partially reversed after a one week treatment with an antacid (Reimann et al., Fortschr Med 102 [1984], 25-26). Therefore the effect of an Aspirin treatment of healthy volunteers with or without an antacid on the prostaglandin synthesis in gastric or duodenal mucosa was investigated. 14C-labelled arachidonic acid was used as substrate during in vitro incubation of the mucosal homogenate for determination of the endogenous formation of prostaglandins. Aspirin suppressed the total prostaglandin synthesis to less than 10% of control after one week treatment. The addition of a high dose antacid did not influence this inhibition, and no significant effect on the prostaglandin profile was detectable. It is concluded that antacids do not influence the suppression of the endogenous prostaglandin synthesis by NOSAC's, however another effect, eg a prolonged stability of PG E2 in a less acidic environment is more likely.

Adult↗
PubMed1986

[Kinetics of germ killing and damage to selected bacterial enzymes by thermal and chemical influences. I. Theoretical background of killing and enzyme inhibition kinetics].

Thermal and chemical influences on microorganisms and the kinetics of microbicidal processes are described in terms suitable to define the resistance of microbes to heat and disinfectants resp. sterilisants. Interactions between active substances (e.g. disinfectants) and enzymes are formulated in equations, and the parameters of kinetics of inactivating enzymes (e.g. Ki-values) are derived. They permit a gradual evaluation of efficacy of microbicidal agents irrespective of their concentration.

Bacteria↗
PubMed1986

[Kinetics of germ killing and damage to selected bacterial enzymes by thermal and chemical influences. II. The thermoresistance of Bacillus subtilis compared to the thermostability of enzymes of this species].

The influence of moist heat on the recultivation of Bacillus subtilis-spores and on the thermal inactivation of two enzymes prepared from this species was investigated. The velocity constant k of destroying microorganisms (determination by counts of B. subtilis-spores with microbiological methods) and the specific activity (determination by biochemical methods) of creatine kinase (EC 2.7.3.2.) and aminopeptidase (EC 3.4.11.2.) were compared. A significant correlation between the logarithm of specific activity and the velocity constant (k/2,303 = 1/D) was found. A thermal exposition for 15 min and 105 degrees C was sufficient for the total inhibition of the activity of creatine kinase and aminopeptidase in the intact spores of B. subtilis.

Aminopeptidases↗
PubMed1986

[Kinetics of germ killing and damage to selected bacterial enzymes by thermal and chemical influences. III. Damage to enzymes from Bacillus subtilis by disinfectants compared to bacterial count reduction].

In the present paper a trial is reported to determine the efficacy of disinfectants by common bacteriological means as well as by biochemical methods. The results are compared, and they reveal a remarkable correlation (r = -0.9476) between the velocity constants of disinfection (1/kw) and the lg 1/Ki(app). The Ki(app)-value is the inhibition constant for the competitive inhibition of the creatine kinase reaction from Bacillus subtilis by disinfectants. The practical impacts are discussed.

Bacillus subtilis↗
PubMed1985

[Synthesis of N-alpha-(8-quinolinesulfonyl)-4-amidinophenylalanine amides as thrombin inhibitors].

The compounds mentioned in the title were prepared starting from 4-cyanophenylalanine by sulfonylation using 8-quinoline sulfonic acid chloride, formation of the 4-nitrophenylester, aminolysis of the latter and subsequent transformation of the cyano via the thiocarbamoyl and the thioimid acid ester into the amidine group. The antithrombin effect decreased by substituting the 1-naphthylsulfonyl by the 8-quinolinesulfonyl residue.

Chemical Phenomena↗