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U Schacht

Publications and source records attributed to U Schacht.

At least 19 recordsLinked to original sources
PubMed1997

[Scaphocapitate dislocation-fracture of the wrist joint in the setting of multiple injury].

Scaphocapitate fracture syndrome (SCFS) as part of perilunar distortion injuries (PL, PLF) in the human wrist is still remarkably rare. The diagnosis is determined by careful physical and radiological examinations, including conventional radiographs. Computed tomography can be helpful in detecting such lesions. In our opinion, the high risk of post-traumatic arthrosis because of carpal instability in a osteoligamental injury requires operative reconstruction in nearly all cases. We report the possibility of operative treatment in a case of scaphocapitate fracture syndrome (Fenton) by implantation of 2-mm mini-bone screws, while the use of K-wires or Herbert bone screws has been described in former articles.

Accidental Falls↗
PubMed1991

Synthesis and biological activity of new HMG-CoA reductase inhibitors. 3. Lactones of 6-phenoxy-3,5-dihydroxyhexanoic acids.

A group of 43 optically active sodium carboxylates (11a-qq and the corresponding lactones 4 were prepared from respective phenols 8 according to Schemes I-III. Phenols 8 were synthesized from commercially available compounds according to Schemes IV-IX. A number of these HMG-CoA reductase inhibitors 11 exceeded mevinolin's activity in vitro (Tables II and III). Selected lactones 4 effectively inhibited hepatic "de novo" cholesterol synthesis in rats in vivo (Table IV). After po administration to rabbits, 4ff(11ff), 4hh, and notably 11jj reduced plasma cholesterol levels more potently than mevinolin (Table V). Whereas 4ff(11ff) displayed the slight superiority expected according to in vitro data, 4hh and 11jj were considerably more potent than expected. Each of these compounds had only moderate activity after po administration to dogs (Table VI). Compound di-11ii, a hybrid of the structural elements of probucol and HMG-CoA reductase inhibitors, after po administration to rats decreased serum lipoproteins and increased HDL/LDL ratio better than probucol (Table VII). HMG-CoA reductase inhibitor 11ll and phenolic building blocks 8, notably 8jj and 8kk, inhibited LDL oxidation in vitro (Table VIII). Chemical structure-activity relationships (Table IX) and the pharmacological profile of phenoxy-type inhibitors 11 diverged from those of known HMG-CoA reductase inhibitors.

Animals↗
PubMed1988

4,4-Diphenylpiperidine derivates and their sila analogues. A comparative study of their interaction with neural receptor biding sites and synaptosomal monoamine uptake.

The potential anti-Parkinson drugs 1-R-4,4-diphenylpiperidines and 1-R-4,4-diphenyl-4-sila-piperidines (R = H, CH3, i-propyl and t-butyl) were evaluated for their neuroreceptor affinity with respect to their structure-activity relationship. In these compounds substitution of the central carbon at position 4 by a silicon leads to more lipophilic substances. While the binding of these compounds to dopamine, serotonin and gamma-aminobutyric acid/benzodiazepine receptors is relatively non-specific, the binding to the mu- and delta-subtypes of opiate receptors and to the 1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine receptor binding site show probably pharmacologically relevant effects. In almost all cases the sila-compounds have a slightly higher receptor affinity than the corresponding carbon-compounds. The studies on the uptake sites for the biogenic amines noradrenaline, dopamine and serotonin, on the other hand, reveal some considerable differences between the carbon- and silicon-containing analogues. The 4,4-diphenyl-4-sila-piperidine has much stronger uptake inhibiting properties for noradrenaline and serotonin than the corresponding carbon compound.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1988

Synthesis and biological activity of new leukotriene antagonists (racemates and enantiomerically pure compounds).

Two series of structural analogues of leukotrienes C4, D4 and E4 (LTC4, LTD4, LTE4) were prepared. The compounds were evaluated for their ability to antagonize leukotriene-induced contractions of guinea pig lung strips. In comparison to FPL-55712, compounds 1a and 2h were more potent antagonists against LTC4 (2- and 3fold, respectively) and LTD4 (6- and 60fold respectively). Moreover, in vivo compounds 1a and 2h exhibited antagonism against leukotrienes (C4, D4, E4) and PAF, the most potent mediators in bronchial asthma. 2h also showed antagonistic activity when tested by inhalation.

Animals↗
PubMed1987

Resolution, absolute stereochemistry, and enantioselective activity of nomifensine and hexahydro-1H-indeno[1,2-b]pyridines.

Nomifensine and three selected compounds from the series of H4a,H5-trans,H4a,H9b-cis-2,3,4,4a,5,9b-hexahydro-1H-in deno[1,2-b]pyridines have been resolved into their enantiomers. All compounds exhibit pronounced enantioselective activity with respect to their inhibition of tetrabenazine-induced ptosis and potentiation of yohimbine toxicity. Nomifensine exhibits the same preference for one enantiomer with respect to dopamine and norepinephrine reuptake, whereas in the indeno[1,2-b]pyridine series in vitro experiments do not discriminate between the optical antipodes. The absolute stereochemistry of the pharmacologically active enantiomers in both series was determined by X-ray analyses and comparative CD spectra. For biological activity the diphenylmethane is an essential structure feature in both series. Its absolute configuration proved to be 4S for nomifensine and 5S for indenopyridines. The similar pharmacological profile of the two chemical entities is therefore reflected in an identical configuration of this pharmacologically important molecular part.

Animals↗
PubMed1984

Stereoselective inhibition of synaptosomal catecholamine uptake by nomifensine.

The effects of the two enantiomers of the antidepressant nomifensine on catecholamine uptake were investigated using rat brain synaptosomes. According to the results from in vitro and ex vivo/in vitro studies, the inhibitory activity on catecholamine uptake resides entirely in the (+)-form of nomifensine. Further studies comparing the antidepressant effects of the two enantiomers might help to clarify the validity of the catecholamine hypothesis of depression.

Absorption↗
PubMed1984

2,3,4,4a,5,9b-Hexahydro-1H-indeno[1,2-b]pyridines: potential antidepressants.

The synthesis of various diastereoisomeric H4a,H5-cis,H4a,H9b-cis- and H4a,H5-trans,H4a,H9b-cis-2,3,4,4a,5,9b-hexahydro -1H-indeno[1,2-b]pyridines is described, as well as the evaluation of their antidepressant potency. Elucidation of structure-activity relationships revealed the H4a,H5-trans compounds as being by far the more active of the two series of diastereoisomers. Pharmacological and biochemical data suggest that these compounds are potential antidepressants with central stimulating properties, which are characterized by strong norepinephrine and dopamine reuptake inhibition.

Animals↗
PubMed1982

[Diagnosis and therapy of colorectal polyps with special reference to adenomas].

Colo-rectal adenoms occur more frequently in the elderly and should be considered as precancerous. The structural changes of the glandular epithelium are known as dysplasia or atypia and are classified into three grades of severity; the "severe epithelial dysplasia" has all the histological characteristics of a malignant tumor which however has not infiltrated the muscularis mucosa and so has not gained access to the lymphatic system. Whenever these structural changes were present the terms focal carcinoma or carcinoma in situ were used. However in 1976 the WHO accepted to change the nomenclature to "severe epithelial dysplasia", as Morson had proposed. Their aim was to avoid superfluous radical surgical intervention. Whenever severe dysplasia is present in an adenoma, the necessary therapy is the local excision of the adenoma together with its pedick. An exact complete histological examination is necessary. Between 1976 and 1980 we saw 201 cases of adenoma of the colon or rectum at the Surgical Clinic, University of Düsseldorf. 27 of these cases showed severe epithelial dysplasia. As described in the literature there was a correlation between the size of the adenoma, the histological picture and the risk of malignancy. The reexamination of 105 patients showed that there was a significant percentage of recurrency at the site of excision or new polyps at a different site. Therefore, regular checkups are a must for all those patients in whom polyps of the large bowel have been removed.

Adenoma↗
PubMed1980

Effects of cimetidine and pirenzepine on peroperative electrical vagal stimulation of gastric acid secretion.

Atropine and an eightfold greater amount of pirenzepine inhibit pentagastrin-stimulated secretion to nearly the same extent (70-75%). Neither drug influences acid concentrations markedly (18%). Atropine and pirenzepine decrease the potassium concentration of gastric juice. By increasing electrical vagal stimulation the inhibitory effect of cimetidine decreases. In contrast, inhibition of vagally stimulated secretion by pirenzepine or by atropine averages 45%, when vagally stimulated secretion amounts to more than 50% of the pentagastrin-stimulated secretion. Thus pirenzepine inhibits gastric secretion similarly to atropine. These results support the hypothesis of a histamine and a cholinergic receptor.

Adult↗
PubMed1979

In vitro studies on GABA release.

1 Recent studies have demonstrated growing evidence for a primary action of the benzodiazepines on gabaminergic neurones which induces a facilitation of gamma-aminobutyric acid (GABA)-mediated neurotransmission. As enhancement of GABA release has been suggested to account for their activation of GABA mechanisms, the effect of diazepam and clobazam, and of several other psychotropic drugs, on stimulated GABA release have been studied. 2 Using rat brain cortex slices saturated with [3H]-GABA, the electrically stimulated overflow of GABA is reduced in a concentration-dependent manner in the presence of both diazepam and clobazam. 3 The benzodiazepine-induced reduction in GABA overflow during electrical stimulation is antagonized by the GABA receptor blocker bicuculline, whereas bicuculline alone at 10(-6) M concentration does not change the overflow. 4 Among some other centrally active drugs tested, hexobarbitone and the 'second messenger; cyclic GMP also induce a significant but less marked reduction in GABA release. 5 A schematic model of a central gabaminergic synapse is proposed, which may explain the benzodiazepine effects on stimulated GABA release by suggesting an inhibitory feedback control of transmitter release mediated by presynaptic GABA receptors ('autoreceptors').

Animals↗
PubMed1979

[Lymphographic visualization of the rectal lymphatic channels and nodes].

Injection of Lipiodol U.F. was effected in the submucosa of the rectum. Injection was done exactly 1,6 mm into the wall. This created a wheal from which reflux of the contrast medium occured. Up to 5 ml Lipiodol U.F. were injected in this manner. Roentgenograms were made in two planes after 2,4,8,24 and 48 hours; occasionally, oblique or spotfilm exposures were taken. Accumulation of the contrast medium began after only 2 to 4 hours, usually reaching its maximum after 12 hours. Thereafter, no further lymph nodes became apparent, so that radiographs taken at this time are representative of final stage. This procedure was carried out on 12 patients suffering from rectum carcinoma and on one patient with a villous adenoma. All tumors were located at a depth of 4 to 6 cm. The results are demonstrated by pictures. The lymph was found to flow longetudinally in the wall of the rectum. The order of appearence of the nodes was arbitrary. Due to the small size of the lymph nodes, no preoperative conclusion could be drawn as to wether or not they had become metastatically infested. The postoperative radiographs provided a check in the radicality of the operative procedure, especially in those cases in which lymph nodes had been clearly visible. Because of the viscosity of the contrast medium and because of the quantity that remained in the submucosa and was resorbed by the lymph channels, the method was self-limiting.

Adenoma↗
PubMed1978

[Chemically induced carcinogenesis of stomach of the rat after vagotomy and resection (author's transl)].

180 male Wistar-rats were daily exposed to 30 and 100 mg MNNG/1000 ccm tapwater. After 7 weeks exposure a truncal vagotomy with pyloroplasty or a Billroth-II-resection was performed in 25 animals of each dosage-group. 80 rats were not operated. The incidence of carcinomas in the Billroth-II-rats of both dosage-groups was evidently higher than in the exposed controls. In the vagotomized rats an increased occurrence of carcinomas could not be observed.

Animals↗
PubMed1977

[Stimulation of H+ secretion and serum gastrin by intra-operative electrical vagal stimulation before and after proximal selective vagotomy (author's transl)].

H+ secretion and gastrin concentration were measured before and after electric vagal stimulation during proximal selective vagotomy in 29 patients with duodenal ulcers. Before vagotomy, H+ secretion and serum gastrin concentration significantly rose after stimulation, while after complete vagotomy H+ secretion remained below basal values, although serum gastrin concentration was significantly increased. These results indicate that without vagal innervation there is no gastrin secretion within physiological levels. The method is suitable for testing the completeness of the vagotomy, the results not agreeing with those obtained by pressure measurements (Burge's method).

Duodenal Ulcer↗
PubMed1977

Pharmacological and biochemical studies with three metabolites of nomifensine.

Three major metabolites (M1, M2, M3) of nomifensine (8-amino-1,2,3,4-tetrahydro-2-methyl-4-phenyl-isoquinoline) are formed by hydroxylation and methoxylation of the phenyl ring. They were compared with nomifensine 1. in various psychopharmacological tests in vivo, carried out in mice after oral or i.p. treatment and 2. in neurochemical in vitro studies, measuring inhibition of noradrenaline (NA), dopamine (DA), and serotonin (5-HT) uptake in rat brain synaptosomes. M1 (4'-hydroxy-nomifensine) was the most active metabolite, while M2 and M3 had little or no effect in pharmacological tests. M1 reversed reserpine hypothermia in doses greater than 2.5 mg/kg, antagonized tetrabenazine catalepsy (ED50 68 mg/kg) and reversed oxotremorine hypothermia (ED50 33 mg/kg). In these tests nomifensine was also active, being about 3-10 times more potent than M1. In contrast to nomifensine M1 had also serotoninergic activity, potentiating both phenelzine-induced twitching (ED50 11 mg/kg) and the anticonvulsant effect of 5-hydroxytryptophan. Moreover, M1 prolonged the hexobarbital sleeping time in doses greater than 10 mg/kg, prevented nicotine-induced convulsions (ED50 58 mg/kg) and reduced the oxotremorine tremor (ED50 59 mg/kg). The LD50 of M1 was 1100 mg/kg orally. In vitro M1 was equipotent with nomifensine in inhibiting DA uptake (IC50 1.5 x 10(-7) M) and twice as active in inhibiting NA uptake (IC50 1.1 x 10(-8) M). In contrast to nomifensine M1 was also a potent inhibitor of 5-HT uptake (IC50 3.3 x 10(-7) M). M2 and M3 were less active than M1 in all experiments.

Animals↗