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Biomedical subjects

R Baumann

Publications and source records attributed to R Baumann.

At least 163 records · Page 9Linked to original sources
PubMed1986

Hypoxic incubation leads to concerted changes of carbonic anhydrase activity and 2.3 DPG concentration of chick embryo red cells.

Red cell carbonic anhydrase activity, 2.3 DPG concentration, and activities of three key enzymes controlling DPG metabolism (PK, PFK and DPGM) were measured in normoxic and hypoxic (incubation in 13.5% O2) chick embryos. In normoxia 2.3 DPG concentration and carbonic anhydrase activity begin to increase by the third week of incubation. Hypoxia induces a rise of 2.3 DPG concentration and carbonic anhydrase activity by Day 8 of development, i.e., 1 week earlier. Since during normal development chick embryos become hypoxic in the third week of incubation, the results suggest that PO2 has a controlling influence on the timing of differentiation events of definitive embryonic red cells.

Animals↗
PubMed1986

[Sterilization reversal with additional use of fibrin glue (Beriplast). Preliminary report].

This is a report on the first use of a fibrin adhesive in microsurgical refertilisation. During the period between 4.4. 1984 and 11.11. 1985 a total number of 17 women were operated on with the additional use of this fibrin adhesive. In the first group, operated on between 4.4. 1984 and 14.11. 1984, three pregnancies have occurred so far. On 6.4. 1985 the first patient of this group gave birth to a boy weighing 3050 gr. To our knowledge this is the first delivery world-wide that was effected with the additional use of fibrin adhesive. Laparoscopy of tube function of a further patient in this group who had not become pregnant after 12 months revealed normal anatomical conditions in the region of the refertilised tube as well as perfect patency. Two cases of intrauterine pregnancy are known in another group of 6 women operated on between 13.2. 1985 and 15.5. 1985. In five patients the follow-up period is less than 4 months, and hence these have been excluded from evaluation. No ectopic pregnancies are known so far. We believe we can sum up as follows in respect of preliminary results: Additional use of fibrin adhesive in the refertilisation of fallopian tubes will not result in enhanced risk of renewed closure. It will be possible to develop suture-free techniques of anastomosis after appropriate development. Operation times get shorter by using fibrin adhesive and the stress exercised on the patient by anaesthesia is reduced. There does not seem to be any enhanced risk of ectopic pregnancy.

Adult↗
PubMed1986

[Digestive manifestations in a patient with type-IIB multiple endocrine neoplasms].

The IIB or third type of multiple endocrine neoplasia is a very uncommon hereditary disease. It includes a digestive ganglioneuromatosis, a typical dysmorphia, a medullary thyroid cancer (MTC) sometimes a pheochromocytoma and seldom a hyperparathyroidism. We report a Men IIB case in a 19 years old patient who had been suffering from severe constipation and afflicted with a megacolon, known since early infancy. Diagnosis was documented by discovering a colonic ganglioneuromatosis and a MTC. A complete thyroidectomy was performed but cervical node metastasis were already present. The ganglioneuromatosis usually affects the whole alimentary tract, but megacolon although not regularly found occurs most frequently. Awareness of the diagnosis is easier when patients have big lips, eyelids, tongue (due to mucosal neuromas) and marfanoid habitus. The prognosis depends upon the MTC. It occurs early in the life, is often bilateral and has a trend to become uncontrollable in the young adult. The pheochromocytoma is often latent and affects only half of patients. The etiopathogeny of this disease still remains unknown. Family inquiry may help to an earlier diagnosis and therefore to a better prognosis.

Adult↗
PubMed1985

Ultrasonic absorption studies of protein-buffer interactions. Determination of equilibrium parameters of titratable groups.

The acoustic absorption of protein solutions in the presence of phosphate and other buffering ions has been studied in the physiological pH range. Buffers containing hydroxyl residues as titratable groups cause a pronounced increase of protein sound absorption, which is attributed to relaxation processes of proton transfer reactions between buffer ions and accessible imidazole and alpha-amino groups of the protein surface. Amino group based buffers like Good's buffers do not induce additional sound absorption. Measurement of the ultrasonic absorption as a function of pH and of buffer concentration, and corresponding parameter fitting of the equation describing proton transfer relaxation processes has been used to evaluate equilibrium parameters. For the imidazole group of the amino acid histidine a pK value of 6.22 and for the imidazole group of the protein lysozyme a pK value of 5.71 have been determined. In hemoglobin the ligand-linked pK changes have been monitored by recording ultrasonic titration curves.

Buffers↗
PubMed1985

[Nuclear spin tomographic studies in liver diseases].

Various diseases of the liver were studied by nuclear resonance tomography using a supra-conductive magnet, with 0.5 T field strength, and the value of the method for the diagnosis of these conditions has been studied. MR tomography is superior to CT for differentiating between solid and fluid lesions, such as haemangiomas since, by choosing suitable techniques, high contrast can be achieved without enhancement. Most diffuse parenchymal diseases and heterogeneous malignant tumours show little change in relaxation times and therefore cannot be diagnosed with great sensitivity or specificity. Nuclear magnetic tomography cannot replace the sonographic, CT and nuclear medicine techniques used for examining the liver, but is a useful addition for special problems.

Carcinoma, Hepatocellular↗
PubMed1984

Organic phosphates increase the solubility of avian haemoglobin D and embryonic chicken haemoglobin.

The isolated minor haemoglobin fractions (haemoglobin D) of ostrich, chicken and duck haemoglobin, which constitute about 30% of total intracellular haemoglobin, form crystalline aggregates upon deoxygenation at physiological temperature, ionic strength and pH and at haemoglobin concentrations even well below those present in the red cell. The aggregation is reversed by oxygenation, and can be inhibited by addition of organic phosphates or the corresponding major haemoglobin fraction in a stoichiometric ratio of 1:1. Embryonic haemoglobin from chicken has similar characteristics with respect to its solubility. The results indicate close functional homology of alpha D and embryonic pi-chains as well as a novel role for organic phosphates in the regulation of haemoglobin function.

Adenosine Triphosphate↗
PubMed1984

Oxygen and carbon dioxide transport in the blood of the muskrat (Ondatra zibethica).

We have investigated the oxygen and carbon dioxide transport properties of a small diving mammal, the muskrat (Ondatra zibethica), where the hemoglobin primary structure has been established by Duffy et al. (1978). While whole blood oxygen capacity, the Haldane effect and the buffer capacity are not different compared to non-diving mammals of similar size, the Bohr effect and the oxygen affinity are increased. The oxygen half saturation pressure (P50) was 26.1 mm Hg (3.5 kPa) at pH 7.4, and the Bohr effect -0.66 (related to plasma pH) and -1.07 related to cell pH. The high affinity of muskrat blood is caused by a comparatively small effect of 2,3 DPG and CO2 on muskrat hemoglobin, that is accentuated through a relatively low concentration of 2,3-DPG in the muskrat red cell. The increased Bohr effect is caused primarily through the pronounced pH dependence of oxygen-linked binding of 2,3-DPG. The weak interaction of muskrat hemoglobin with 2,3-DPG is not caused by substitutions at the binding site.

Animals↗
PubMed1984

Oxygen binding properties of hemoglobin from the white rhinoceros (beta 2-GLU) and the tapir.

The beta-chain of rhinoceros hemoglobin contains glutamic acid at position beta 2, and important site for the binding of organic phosphates. We have investigated the oxygen binding properties of this hemoglobin and its interaction with ATP, 2,3-diphosphoglycerate, CO2 and chloride. The results show that the presence of GLU at position beta 2 nearly abolishes the effect of organic phosphates and CO2, whereas the oxygen-linked binding of chloride is not affected. Thus rhinoceros hemoglobin has only protons and chloride anions as major allosteric effectors for the control of its oxygen affinity. From the results obtained with hemoglobin solutions it can be calculated that the blood oxygen affinity of the rhinoceros must be rather high with a P50 of about 20 torr at pH 7.4 and 37 degrees C, which conforms with observations obtained for other large mammals.

Animals↗
PubMed1984

[Nuclear spin tomographic study of the facial skeleton. I. Nuclear spin and computed tomographic anatomy].

The resolution of NMR and CT was compared using axial sections of the normal anatomic structures of the facial skeleton. It was shown that NMR was superior in differentiating muscles, tonsils, mucosa, lymph nodes and blood vessels. The demonstration of bone and its differentiation from air-containing spaces is often difficult. Metallic, non-ferromagnetic dental fillings, which cause serious artefacts on CT, do not affect NMR.

Adult↗
PubMed1984

Mono-, di- and triglycerides in serum of spontaneously hypertensive and normotensive rats in relation to age.

Serum triglycerides appeared significantly lower in spontaneously hypertensive as compared to normotensive rats except in 8-week-old animals. Tri-, di and monoglycerides decreased continuously with age in the former but revealed only a transient fall in the latter. The remarkably high portion of partial glycerides (about 30% of total glycerides) in serum should be considered in all studies on lipolysis in rats.

Aging↗
PubMed1984

[Cholesterol crystals and biliary lithiasis. Importance of the study of bile collected by duodenal intubation].

Cholesterol crystallization in a necessary step in the formation of cholesterol gallstones. Our purpose was to study the relationship between the presence of biliary cholesterol crystals and radiolucent gallstones. Bile was obtained by duodenal intubation from 60 subjects free of hepatic disease: 40 patients had radiolucent gallstones and in the remaining 20 subjects no gallstones could be found either by oral cholecystography or by ultrasound examination. In each patient a bile sample was used to search for cholesterol crystals; in another sample, biliary cholesterol, phospholipids and bile acids were measured to calculate the lithogenic index. Among the 44 subjects with lithogenic bile, 34 had radiolucent gallstones. Twenty-two out of the 60 patients had both cholesterol crystals and radiolucent gallstones; 21 subjects out of the 22 had lithogenic bile. In patients with frequent biliary colic or subacute pancreatitis without visible gallstones, finding cholesterol crystals in bile might suggest medical or surgical specific treatment.

Adult↗