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Biomedical subjects

A Hoffmann

Publications and source records attributed to A Hoffmann.

At least 307 records · Page 17Linked to original sources
PubMed1991

[The bioequivalence of doxycycline in two preparations in capsule form].

In a randomized cross-over study the bioavailability of doxycycline (CAS 17086-28-1) in two preparations was examined by determining AUC and Cmax. The bioavailability of Doxycyclin-Kapseln (T = test preparation) relatively to a reference preparation (R) in 20 healthy subjects. Statistical analysis of plasma concentration curve and maximum concentration showed no differences between the pharmaceutical preparations tested. Both preparations proved to be bioequivalent.

Adult↗
PubMed1991

A technique for cardiac denervation in Megalobulimus sanctipauli (Mollusca, Gastropoda, Pulmonata).

Cardiac nerve of Megalobulimus sanctipauli can be accessed by making an incision of about 1 cm with the aid of a scalpel introduced into the connective tissue (whitish scar) joining a fold of the anterior lobe of the digestive gland. The existence of an externally identifiable anatomic characteristic (whitish scar) facilities access to the nerve thus preventing large hemolymph loss. The percentage of hits of the technique was evaluated in two different groups (N = 14 and 17) of animals, with positive results obtained for 86% and 88%, respectively. The survival rate determined 13 days after surgery for one experimental group (N = 14) was 71%.

Animals↗
PubMed1991

Heart rate and behavioral patterns of Megalobulimus sanctipauli (Mollusca, Gastropoda, Pulmonata).

Adult specimens (N = 20) of the pulmonate land snail Megalobulimus sanctipauli were observed systematically in the laboratory and four behavioral patterns reflecting different degrees of activity are described. The changes in heart rate associated with different behavioral patterns were monitored using three silver chloride electrodes chronically implanted in the visceral mass of the animals (N = 13). Continuous heart rate recordings were performed at room temperature (25 degrees C) with a Nihon Kohden polygraph model RM-45. Analysis of the results by the Multiple Comparisons Test based on Friedman rank sums revealed significant differences in heart rate, reported as median, between the following behaviors: retracted into the shell and locomotion, 25 vs 35 (P less than 0.008), retracted and eating, 25 vs 38 (P less than 0.008), still with local activity and eating, 33 vs 38 (P = 0.021). These results indicate that different levels of activity have different effects on the cardiac function of Megalobulimus sanctipauli. The lowest heart rate was associated with the animal retracted into the shell. The highest rates were related to locomotion and feeding behaviors.

Animals↗
PubMed1991

Isolation and characterization of a thrombin inhibitor from the tick ixodes ricinus.

The secretion of the salivary glands of ticks, Ixodes ricinus, contains anticoagulant substances. Some years ago an antithromboplastin, ixodin, was described. The present paper refers the isolation and characterization of a second anticoagulant substance of the ticks named ixin. Ixin proved to be a relatively stable and specific thrombin inhibitor. The multi step procedure for isolation results in a 850-fold purification. The preparation obtained has a specific activity of 250 antithrombin units/mg. It is not homogeneous and still contaminated. The substance was assumed to be a miniprotein.

Amides↗
PubMed1991

[The effects of verapamil and nifedipine on the biotransformation of model substances and on the indocyanine green elimination].

Twelve healthy subjects received a cocktail of model substances (containing metamizol: 1000 mg, caffeine: 200 mg, sulfadimidine: 500 mg, and debrisoquine: 10 mg) alone and on the fifth day of a five day therapy of oral verapamil (3 x 80 mg) or nifedipine (3 x 20 mg) to assess the effect of verapamil and nifedipine on hepatic biotransformation. To investigate liver blood flow intravenous indocyanine green (0,5 mg/kg) was given 12 and 1 hours after oral verapamil (80 mg) or nifedipine (20 mg). In the presented study an influence of verapamil and nifedipine treatment on the hepatic drug oxidizing system was not observed. The elimination half-life of intravenous indocyanine green was only 1 hour after oral nifedipine (20 mg) significantly decreased. 12 hours after nifedipine (20 mg) or verapamil (80 mg) as well as 1 hour after verapamil (80 mg) treatment no change in indocyanine green elimination was observed. The estimated increase of liver blood flow after oral nifedipine may cause increased absorption of other oral administered drugs and may accelerate hepatic elimination of drug with high hepatic extraction rate. 6 fast an 6 slow acetylators were found. This classification did not change after nifedipine or verapamil therapy.

Adult↗
PubMed1991

[Experiences with the Günther filter].

In the investigation 17 patients with lung embolism being cared for with a Guenther-filter were post-observed during a period up to two years. Early complications after the implantation of the Guenther-filter did not occur in any case. Late complications after the implantation of the Guenther-filter were dislocations, deformations of the filter and breaks of the spokes. In the result of the post-observation the Guenther-filter application despite its easy handling should be regarded very critically.

Aged↗
PubMed1990

The ATPase of Bacillus alcalophilus. Purification and properties of the enzyme.

The ATPase of Bacillus alcalophilus was extracted from the bacterial membranes with Triton X-100 and purified by hydroxyapatite column chromatography. SDS gel-electrophoresis of the purified protein indicated the typical subunit pattern of an F1F0 structure with five F1 subunits (alpha, beta, gamma, delta, epsilon) and three F0 subunits (a,b,c). The alpha and beta subunits were antigens for an antiserum against the corresponding subunits of the ATPase of Escherichia coli. Subunit c was extracted from the bacterial membranes with chloroform/methanol. Its amino acid composition was in the range of subunits c from other ATPases. Maximal ATPase activity was observed in the presence of 2-5 mM MgCl2, an ATP/Mg2+ ratio of 2:1 and 25% methanol. In the absence of methanol, only about 1% of the maximal activity was observed. The enzyme was also activated by Ca2+ (in the absence of methanol), reaching about 30% of the maximal activity. The dependence of initial velocity versus ATP of the Ca2(+)-activated but not of the Mg2+/methanol-activated enzyme indicted cooperativity with three strongly cooperative binding sites.

Adenosine Triphosphatases↗
PubMed1990

[Detection of antibodies against Brucella in the aqueous humor using ELISA].

In aqueous bulbi of experimentally against Brucella abortus immunized guinea pigs and rabbits specific antibodies could be detected by ELISA-tests. This first demonstration of brucella antibodies in the aqueous shows that aqueous can be used for serological examinations. For practical use more investigations in experimental animals are necessary, e.g. on kinetics of orbital antibodies absence of interfering factors and biomechanics of proteins in aqueous.

Animals↗
PubMed1990

[Vascular risk factors in patients with ophthalmoplegia].

The occurrence of high-risk factors for vascular disorders was analysed in a group of 43 patients suffering from diplopia of unknown aetiology. The subjects (25 men and 18 women) were aged between 17 and 78 years. Previously excluded were patients with intracranial or orbital tumors, ocular myositis or myasthenia, multiple sclerosis, endocrine orbitopathy, head trauma, cerebral hemorrhage or aneurysms, leucaemic infiltrates or metastasising tumors. Compared to the control groups of extensive epidemiological studies, the patients showed a higher prevalence of arterial hypertension and diabetes mellitus. Adipositas, lipometabolic disturbance and cigarette smoking were also more frequent. The findings support the hypothesis of a vascular origin of eye-muscle paresis.

Adolescent↗