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Biomedical subjects

H Schmidt

Publications and source records attributed to H Schmidt.

At least 955 records · Page 53Linked to original sources
PubMed1982

Experimental evidence for an "internal leak" of cat gastric mucosa after stimulation with histamine and carbachol.

Numerous factors are involved in the pathogenesis of gastric ulcer. Possibilities under discussion are acid back diffusion, a reduction in the quality of the gastric mucus, and vascular factors that give rise to local ischemia. One hypothetical model presented for consideration, is based on the notion of an "internal leak", as a result of which acid escapes out of the parietal cells directly into the interstitium. Using the cationic dye acridine orange in cats, it has been possible to show, in particular after prior stimulation with stimulation with histamine and carbachol, but not with pentagastrin, that a microfocal accumulation of the dye in the interstitium can indeed be found. Under conditions of hypoxia, this phenomenon was not observed. In view of the specific properties of the dye, it may be concluded that, under certain conditions, acid substances can indeed diffuse out of the parietal cells into the interstitium. this animal model offers distinct findings compatible with the pathogenetic concept of an "internal leak".

Acridine Orange↗
PubMed1982

Opioids modulate intestinal peristalsis at a site of action additional to that modulating acetylcholine release.

The nature of the interaction between cholinergic and opioid mechanisms controlling peristalsis in the intact segment of the guinea-pig ileum was examined. The induction of rhythmic peristaltic activity by acetylcholine was dose dependently inhibited and facilitated by preapplication of, respectively, normorphine and naloxone. The action of intestinal opioids occurs, at least partially, at a site of action differing from that modulating the release of acetylcholine from the myenteric plexus. Interruption of the peristaltic reflex by hexamethonium, atropine, tetrodotoxin or desensitization of the segments to serotonin also strongly impaired or abolished the initiation of circular muscle contractions produced by naloxone. Therefore, no indication could be found for a direct action of naloxone upon the circular muscle. Rather, intestinal opioids appear to be involved in regulating the activity of the reflex arc.

Acetylcholine↗
PubMed1982

[Afterloading method for the irradiation of malignant bile duct obstructions].

A new method is presented for the irradiation of malignant bile duct obstructions employing the percutaneous transhepatic drainage canal and based on the application by means of the afterloading system of Iridium-192 into the bile duct. This method allows for the first time to apply high doses directly to the tumors within the bile ducts without causing damages to the surrounding sain tissues.

Biliary Tract Neoplasms↗
PubMed1982

Trypanosoma brucei rhodesiense infection in vervet monkeys. I. Parasitologic, hematologic, immunologic and histologic results.

Twenty vervet monkeys infected with T. rhodesiense (Eatro 1989) developed chronic disease with an average duration of 65 days (variation 35-107 days). With respect to the course of the disease, and to the hematologic, immunologic and histological findings, the disease faithfully mirrored human T. rhodesiense infection. In all animals, parasitization of the CSF occurred only a few weeks after infection, and was accompanied by an increase in the cell count and the appearance of IgM in the CSF. The main histopathological feature was severe pancarditis which was responsible for death in almost all animals. Chronic leptomeningitis resulted as histological substrate of the early parasitosis of the CSF. In most animals meningitis was accompanied by a mitigated encephalitic early reaction characterized by sparse lymphoplasmocytic infiltrates, exclusively of the cerebral vessels, with a predilection for the base of the brainstem and the neighbourhood of the ventricles. Autonomous meningoencephalitis with parasites in the brain tissue was found in only one animal (with the longest survival period of 107 days). In view of the regular parasitosis of the CSF, T. rhodesiense infection of the vervet monkey may be considered a suitable animal model for the assessment of the liquor "uptake" of trypanocidal drugs.

Animals↗
PubMed1982

Trypanosoma brucei rhodesiense infection in vervet monkeys. II. Provocation of the encephalitic late phase by treatment of infected monkeys.

Four out of 8 monkeys infected with Trypanosoma rhodesiense and treated with trypanocidal drugs at various intervals after infection (days 55-58, days 62-65, day 68) developed encephalitis. In 2 of these animals, killed 2 weeks after treatment, the encephalitis presenting was incipient; the other 2 monkeys died as a result of severe encephalitis a little more than 2 and 3 months after treatment, respectively. At the time of treatment, the animals revealed a parasitization of the CSF, but there were no clinical or neurological signs of any involvement of the central nervous system. The observations confirm observations made in human trypanosomiasis, and in experiments on rodents, which indicate that the encephalitic late phase may result from inadequate treatment. These observations may indicate that the encephalitis of the late phase may be methodologically provoked by infection and subliminal treatment after parasitization of the CSF, and that this procedure may be more promising of success than the method of infection only, as a method for the production of an animal model of the encephalitic late phase.

Animals↗
PubMed1982

[Hemodynamics of the St. Jude Medical aortic prosthesis in comparison to the Björk-Shiley and Lillehei-Kaster prostheses].

Pre- and postoperative hemodynamic data in 10 patients in whom the aortic valve was replaced by a St. Jude Medical (SJM) prosthesis are compared with those in 29 patients who received a Lillehei-Kaster tilting disk (LK) valve prosthesis and 11 patients with a Björk-Shiley tilting disk (BS) valve prosthesis. The SJM aortic prosthesis of the small size (A 21) has advantages over the LK and BS types, and it is therefore particularly suited to use in a small aorta. There are also good hemodynamic results for the larger sizes of the SJM prosthesis. As a result of the 85-degree opening angle and the favorable ratio between the inner and outer diameters of the valve (suture ring), there is only minor impedance of blood flow. The SJM aortic prosthesis thus involves a lesser degree of hemolysis than the BS and the LK. In spite of the promising hemodynamic data, however, long-term findings on the durability of the SJM prosthesis in vivo have not yet been published. It therefore seems to us justifiable, especially where the aorta is large, to continue to use BS prostheses.

Aged↗
PubMed1981

Release of immunoreactive-dynorphin from the isolated guinea-pig small intestine is reduced during peristaltic activity.

The guinea-pig small intestine contains high amounts of immunoreactive dynorphin (9 pmol/g), which is released from the in vitro preparation under resting conditions (basal release). Initiation of peristaltic activity by distension of the intestinal wall via sustained elevated intraluminal pressure lowers the levels of immunoreactive dynorphin in the bathing solution (by more than 60%). The present data are suggestive of a role of this endogenous opioid peptide in the control of intestinal peristalsis.

Animals↗
PubMed1981

[The ultrastructure of intestinal amyloidosis].

Amyloidosis nearly always goes along with manifestations of the gastrointestinal tract. It can mimic a variety of different clinical syndromes. Pathogenetically amyloidosis leads to an organ insufficiency due to local infiltration of amyloid or to replacement of tissue with amyloid fibrils. Characteristic ultrastructure is composed of an irregular network of fibrils without any periodicity. The topographic position gives an explanation for the intestinal symptoms. Involvement of the intramural nerve system is responsible for motility disorders like diarrhoea or constipation. In case of perivasal infiltration hemorrhage and inflammatory changes can be found, as well as malabsorption syndromes, when subepithelial amyloid layers are present. Electron microscopy therefore may contribute to the pathogenetic understanding of morphological findings in regard to clinical symptoms.

Amyloid↗
PubMed1981

[Early diagnosis of primary biliary cirrhosis (author's transl)].

Electron microscopic investigations of liver biopsy specimens in 16 patients with a clinically suspected diagnosis of chronic obstructive non-purulent cholangitis as the early stage of primary biliary cirrhosis showed characteristic changes of the intrahepatic biliary canaliculi. These consist of a coarsening and reduction of microvilli, thickening of pericanalicular ectoplasm and intercellular gaps as well as increasing obliteration of the canalicular lumen. Typical primary biliary cirrhosis developed in 6 patients over an observation period of 3 years. The ultrastructural findings may contribute towards identification of morphogenesis of this disease. They are possibly pathognomonic for the early stage of the disease. However, the precipitating factor remains unknown.

Biopsy↗
PubMed1981

[Double-blind randomized clinical study on treatment of warts with a fluorouracil-containing topical preparation (author's transl)].

In a double blind trial 60 patients were treated with a salicylic acid-containing product against warts (Verrumal) on basis fluorouracil in comparison to placebo. The trial demonstrated a statistically significantly better result for the verum preparation than for the placebo without fluorouracil and without salicylic acid. This product against warts is, therefore, indicated if operative methods are not applicable or refused by the patient.

Administration, Topical↗
PubMed1981

Serotonin and dopamine synthesis in phenylketonuria.

Two regulation systems of the serotonin and dopamine biosynthesis in patients with classical and atypical PKU were investigated. In classical PKU, the serotonin and dopamine biosynthesis is inhibited by high L-phenylalanine in blood and tissues. The dopamine formation in vivo was inhibited by phenylalanine blood concentrations higher than 25 mg/dl: the serotonin formation was inhibited even at a phenylalanine blood concentration of only 8 mg/dl. In two patients with dihydrobiopterin synthetase deficiency, the dopamine, and even more pronounced the serotonin, excretions are considerably reduced. The dopamine excretion was reduced to about 50% and the serotonin excretion to only 10% compared to controls. Under BH4 therapy (16 mg daily), the dopamine values increased about twice, serotonin threefold and the phenylalanine blood concentration normalized to 1-1.5 mg/dl. On loading a patient with BH2 synthetase deficiency with 50 mg/kg deuterated tryptophan-d5 and 150 mg/kg deuterated tyrosine d2 (phenylalanine blood concentration of 16 mg/dl), deuterated dopamine d1 and serotonin d4 could only be formed in detectable amounts after BH4 administration. During BH4 therapy the amount of dopamine d1 and serotonin d4 formed was lower than but comparable to normal controls.

Dopamine↗
PubMed1981

Muscarinic acetylcholine receptor in chick limb bud during morphogeneis.

In the chick embryo a cholinesterase activity appears in various organ anlagen which has been correlated with morphogenetic movements (Drews 1975). The cholinesterase activity is present in the mesenchyme of the limb bud during aggregation of the central chondrogenic core. In the present study binding of tritium labelled quinuclidinyl benzilate ((3H)QNB), a muscarinic antagonist, to homogenates of chicken limb buds was investigated by a filtration assay. In the homogenate of limb buds at Stage 24 specific binding of (3H)QNB was demonstrated. Determination of binding constants and inhibition of binding by agonists and antagonists was studied at Stage 25/26. Specific binding was defined by the difference in binding in the absence and presence of atropine (1 microM). Specific binding of (3H)QNB reflected a muscarinic receptor. The Kd in two experiments was 0.11 nM and 0.16 nM, the binding capacity was 15.7 fmol (3H)QNB/mg protein and 12.0 fmol (3H)QNB/mg protein, respectively. Data on displacement of specific bound (3H)QNB by various nicotinic and muscarinic ligands confirmed the muscarinic nature of the receptor. Muscarinic ligands inhibited the (3H) QNB binding, whereas nicotinic ligands caused no inhibition at pharmacological concentrations. I conclude that a specific muscarinic acetylcholine receptor is part of the cholinergic system whose presence is indicated by cholinesterase activity in the chondrogenic core of the limb bud during morphogenesis.

Animals↗