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Biomedical subjects

D Schulz

Publications and source records attributed to D Schulz.

At least 55 records · Page 3Linked to original sources
PubMed1986

Reactions of OH radicals with poly(U) in deoxygenated solutions: sites of OH radical attack and the kinetics of base release.

Pulse radiolysis of N2O-saturated solutions of poly(U) in the presence of tetranitromethane showed that 81 per cent of the radicals formed are reducing in nature. Using data from other sources it has been estimated that 70 per cent of the OH radicals add to the base at C(5) and 23 per cent at C(6) while only 7 per cent abstract an H-atom from the sugar moiety. To a large extent the C(5) OH adduct radicals attack the sugar moiety of poly(U) thereby inducing strand breakage and base release. G (base release) = 2.9 can be subdivided into three components: (a) immediate (20 per cent), (b) fast (50 per cent) and (c) slow (30 per cent). The immediate base release must occur either during the free-radical stage or as a result of the rapid (t1/2 less than 4 min at 0 degree C) decomposition of a diamagnetic product. The fast and the slow processes are only readily observable at elevated temperatures, e.g. at 50 degrees C the half lives are 83 min and 26 h, respectively (Ea (fast) = 68 kJ mol-1, Ea (slow) = 89 kJ mol-1, A (fast) = 1.5 X 10(7) s-1, A (slow) = 1.9 X 10(9) s-1. It is concluded that there are three different types of sugar lesions giving rise to base release, structures for which are tentatively proposed.

DNA↗
PubMed1986

Noradrenaline modulates calcium channels in avian dorsal root ganglion cells through tight receptor-channel coupling.

Averaged ensemble Ba currents were recorded from tissue cultured embryonic chick dorsal root ganglion (d.r.g.) cells using the cell-attached patch-clamp technique. Noradrenaline (NA) applied to extrapatch membrane had no clear consistent effect on drug-free patch currents. This finding supports a previous suggestion that second messengers may not be involved in NA-mediated decreases in Ca currents in sensory neurones (Forscher & Oxford, 1985). Cell-attached patch currents sometimes increased slowly after extrapatch application of NA, but were not reversibly decreased by drug treatment. Large patch currents were used to trigger cellular action potentials. NA reversibly decreased action potential duration as reflected in extracellularly recorded patch action currents. Simultaneously recorded inward patch currents were not affected. D.r.g. cell adenylate cyclase activity was assayed. NA did not affect intracellular cyclic AMP levels at concentrations which cause 30-70% decreases in gCa in dialysed cells (Forscher & Oxford, 1985). Treatment with forskolin (50 microM) or isoprenaline (10 microM) resulted in 60- and 2-fold increases respectively in adenylate cyclase activity over basal levels. These results suggest that NA decreases Ca currents by direct NA interactions with the Ca channel or a molecule tightly coupled to channel function in d.r.g. cells.

Action Potentials↗
PubMed1985

[Possibilities of surgical and drug therapy of parasitic cholestasis].

Out of 123 patients with hydatid-disease of the liver in 15 patients biliary engorgement by compression from cysts or parasites in the biliary system were observed. Diagnosis can be established by serology, sonography, scintigraphy, ERCP and CT. Invasive diagnostic procedures are not indicated. Surgical therapy of echinococcosis is in the first place; long-term adjuvant chemotherapy by Mebendazole is indicated if the resection of the cysts is not complete.

Amebiasis↗
PubMed1984

[Varioloform (complete) erosions in the stomach and duodenum].

One thousand five hundred and eighty-three patients who were x-rayed for dyspepsia showed varioliform erosions in 15.3%. Men had an incidence of 9.8%, almost twice as common as in women (5.5%). Mucosal polyps, usually of the hyperplastic type, occurred in 2.4%. 15% of patients with gastric ulcers and 16% of patients with duodenal ulcers had varioliform erosions. On the other hand, amongst patients with erosions, 11% had gastric ulcers and 8.3% duodenal ulcers. The definitions of erosion which have been given in the literature are partly contradictory, and are discussed. Varioliform erosions, also known as complete erosions, may be acute or chronic. They are the third most common cause of bleeding from the upper gastrointestinal tract. With modern radiological methods of examining the stomach, they are no longer a rare finding.

Duodenal Diseases↗
PubMed1984

Ultrastructure of Anaulus creticus Drebes & Schulz with special reference to its reduced ocelli.

The ultrastructure of the vegetative cell of the centric diatom Anaulus creticus Drebes & Schulz is described. Exhibiting the organic wall component (diatotepum) separated from the siliceous parts of the cell wall this species belongs to the diatom group with so-called split-walls [17]. A most interesting feature of the Anaulus cell is the horn region and its internal structure. As there is no silicified sieve-plate at the horn top but just a big hole sealed only by a thin diatotepum with a hexagonal meshwork, this wall structure is termed a "reduced ocellus". The inner part of the horn region is largely occupied by a conspicuous protoplasmic plug of proteinaceous nature. The possible function of this peculiar structure is discussed as well as new ideas about the role of the labiate process are provided.

Eukaryota↗
PubMed1982

[Methods of protein gradient determination for diagnostic use in the clinical laboratory].

Computed quotients of the concentrations of individual proteins in serum and in cerebrospinal fluid recorded in a semilogarithmic way against the hydrodynamic radius of the molecules may be connected and so give lineals, the positions of which are believed to estimate the actual function of the blood-brain-barrier (Felgenhauer et al. 1974; 1976). It is demonstrated by examinations of different samples of blood and cerebrospinal fluid, that both the described method and the simple measurement of total protein in cerebrospinal fluid are of the same power in their application to estimate the function of the blood-brain-barrier. However, the method introduced by Felgenhauer et al. enables to demonstrate immunoglobulins not having reached the cerebrospinal fluid by entering from the blood stream and so giving rise to diagnose a local humoral immune response within the central nervous system. In this way the method of Felgenhauer et al. gives advantages to the diagnostics of neurological diseases.

Blood Proteins↗
PubMed1982

[Echinococcus alveolaris--clinical manifestation, treatment and prognosis].

Life-cycle and endemic areas of Echinococcus alveolaris are described with reference to the autonomous character of this parasitosis. Especially human ways of infestation are shown with man's role as definitive host. The natural course of this parasitosis leads obligatory to lingering illness and death. Indication of exploratory laparotomy remains beyond doubt. Based on our own experience and corresponding with other authors importance of radical resection has to be propagated with reservation. Maintaining of the bile flow however is most important with regard to operative mortality, survival time and quality of life--even when performed as palliative surgical treatment. Adjuvant therapy with Mebendazol (Vermox) is considered to be helpful in improving the unfavourable prognosis of this parasitic disease.

Adult↗
PubMed1981

[Mesentericocaval shunt after esophageal bleeding in patients with cirrhosis of the liver; results during a 10 year period (author's transl)].

54 patients with cirrhosis of the liver and relapsing esophageal bleeding received mesentericocaval dacron shunts between 1st January 1975 and 31st December 1979 and were followed up to the end of 1980. Patients were accepted for surgery under the following conditions: (1) liver function had to be compensated, (2) there had to be no signs and symptoms of hepatoportal encephalopathy, (3) there had to be no signs and symptoms of activity of cirrhosis of the liver, (4) liver volume had to be between 1 000 and 2 500 ml, (5) portal vein perfusion had to be 15-35%, (6) stenosis of liver arteries had to be excluded. Lethality during the hospital period and from hepatoportal encephalopathy was 7.4%, late lethality was 11%; this accounted for a 5-year survival rate of 70%. Residual perfusion of the portal vein could be demonstrated in many cases by intra- and postoperative measurements with different methods. The dacron prosthesis was implanted into the superior mesenteric vein in an acute angle (it had a diameter of 16 mm). The prosthesis was occluded by thrombosis in 3 out of the first 18 cases operated upon. This could be prevented in the following 36 patients by intra- and postoperative longterm heparinisation.

Adult↗
PubMed1980

[The suitability of the Pandy reaction for the rapid evaluation of spinal fluid protein concentrations].

The reaction of Pandy ist a qualitative method to detect quickly abnormal protein concentrations in cerebrospinal fluid by precipitation. Because of several interacting influences on the method its use in a semiquantitative way cannot be advised. Globulins will cause more intensive precipitation than albumin. Furthermore both the individual differences in judging several degrees of precipitation and the different governing actual illuminations during the examination impede the method to be applicated in a semiquantitative way.

Cerebrospinal Fluid Proteins↗
PubMed1980

Biological activities of fragments derived from Bordetella pertussis endotoxin: isolation of a nontoxic, Shwartzman-negative lipid A possessing high adjuvant properties.

Endotoxin from fresly sedimented Bordetella pertussis cells, isolated by the phenol/water procedure when submitted to kinetically controlled, mild acidic hydrolysis released a polysaccharide (polysaccharide 1), a complex lipid (lipid X), and a glycolipid. When treated with somewhat stronger acid, the glycolipid yielded a second polysaccharide (polysaccharide 2) and another complex lipid (lipid A). The intact pertussis endotoxin had all the usual properties of endotoxins extracted from enteric bacteria. Lipid X and the intermediary glycolipid retained all the endotoxic properties of the unfractionated endotoxin. In lipid A, pyrogenicity was reduced to a very low level and toxicity and Shwartzman reactivity were absent; however, this fraction retained most of the endotoxin's antiviral activity, and its adjuvant power was considerably higher than that of the intact endotoxin. Lipid A elicited nonspecific resistance against challenge with certain bacteria, but not against others.

Adjuvants, Immunologic↗
PubMed1980

Rotating microtubules as a basis for anaphase spindle elongation in diatoms.

The separation of the spindle poles during anaphase in diatoms can easily be explained by contrarotating microtubules in the two half spindles. A model is presented demonstrating that in such a situation, the electron microscopically observed tetragonal pattern of the antipolar microtubules in the overlap region is the only means to achieve minimal frictional resistance. The consequences of the microtubule-rotating concept are discussed to comparison with other models (e.g. microtubule/microtubule-sliding).

Anaphase↗