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Biomedical subjects

W Bauer

Publications and source records attributed to W Bauer.

At least 127 records · Page 7Linked to original sources
PubMed1988

Structure-function relationships of somatostatin analogs.

Objective of peptide chemistry has always been the production of analogues for clinical application. Advantages sought over natural peptides are (a) reduced molecular size; (b) prolonged biological half-life, and (c) enhanced specificity. After elucidation of the active core of somatostatin a number of analogues have been synthetized. Among them SMS 201-995, an octapeptide, was selected for further development because of its high potency and prolonged plasma clearance. Procedures extending the duration of action of somatostatin derivatives such as enhancement of lipophilicity and amino acid substitution are described, and factors influencing the specificity of such substances are succinctly analyzed.

Animals↗
PubMed1988

[133Xe-DSPECT: significance of the cerebrovascular reserve capacity for the diagnosis and therapy of chronic cerebral ischemia].

Using 133Xe-DSPECT, measurements of regional cerebral blood flow (rCBF) were performed before and after stimulation with 1 g of Diamox in 55 patients with symptomatic occlusion of the internal carotid artery (ICA) and 26 patients without evidence of brain disease (normals). In normals, a negative correlation (r = -0.74) of the Diamox-induced increase of hemispheric blood flow (reserve capacity) and rCBF at rest was observed. In 48 of the 55 patients (87%) with ICA-occlusion a reduced reserve capacity was found. The extent of reduction, however, did not correlate with the findings of transmission CT, because 15 of 21 patients (71%) with normal CT-scans presented a moderate to severe reduction of reserve capacity. In contrast, reserve capacity corresponded to the extent of arterial collateralisation as documented by cerebral panangiography. In 31 patients EC/IC-bypass surgery was performed. In follow-up studies reserve capacity increased, especially in patients who had a severe reduction preoperatively. Therefore, the combined measurement of rCBF at rest and of reserve capacity is a sensitive, non-invasive method for the diagnosis of (even bilateral) cerebrovascular disease and can be helpful to identify patients with hemodynamic ischemia, who may benefit from EC/IC-bypass surgery.

Adult↗
PubMed1987

Analysis of the lipoteichoic-acid-like macroamphiphile from Bifidobacterium bifidum subspecies pennsylvanicum by one- and two-dimensional 1H- and 13C-NMR spectroscopy.

The native lipoteichoic-acid-like amphiphile from Bifidobacterium bifidum subspecies pennsylvanicum and its basic glycan moiety, obtained by alkaline hydrolysis, were studied by 1H-, 13C-, and 31P-NMR, DEPT (distorsionless enhancement by polarization transfer), 1H-1H correlation spectroscopy and 13C-1H shift correlation NMR spectroscopy. The results are consistent with the structure elucidated by chemical analysis (Fischer, W., preceding paper in this journal): (formula; see text) and establish the structures of the repeating units independently. In addition to characteristic shifts in the 13C-NMR spectrum, the sites of phosphodiester and alanine ester bonds are also manifest in the 1H-NMR spectrum. Substitution of the glycerophosphate residues can be recognized in the 31P-NMR spectrum also.

Bifidobacterium↗
PubMed1987

On-line analysis of rapid motion with a microcomputer.

A software package is described, which uses an Apple IIe computer with a digitizing board (Digisector 65) for analysing rapid motions of appendages of small insects from video images. Every 20 ms the program simultaneously analyses the position of two moving appendages after a background correction and the externally applied trigger stimulus. The data may be plotted in high-resolution plots with a matrix printer and evaluated with statistical methods.

Animals↗
PubMed1987

Occurrence of carotenoids and sporopollenin in Nanochlorum eucaryotum, a novel marine alga with unusual characteristics.

Pigment analysis of Nanochlorum eucaryotum on two strains grown under different gaseous conditions was performed. Air-gassed control cultures did not differ qualitatively with respect to the content of chlorophylls a and b, carotenes alpha and beta, lutein, violaxanthin, neoxanthin and cryptoxanthin in comparison with cultures grown under natural gas. The absolute pigment content per cell increased in cultures grown with natural gas. Growth of N. eucaryotum depends on CO2 which is present in concentrations up to 2.0 vol% in natural gas. N. eucaryotum cannot utilize methane and is therefore not methylotrophic. In cultures of N. eucaryotum grown with natural gas and in air-gassed cultures under nitrogen deficient conditions the secondary carotenoids canthaxanthin and astaxanthin could be detected. In air-gassed cultures of strain N. eucaryotum Colona the same secondary carotenoids have been found, while secondary carotenoids were never found in strain N. eucaryotum Mainz. Cell walls of N. eucaryotum always contain sporopollenin as confirmed by isolation, elemental analysis, infrared absorption spectrophotometry, acetolysis-resistance and electron microscopy.

Biopolymers↗
PubMed1986

Sleep apnea and pulmonary hypertension.

The pulmonary artery pressure values of 65 patients with sleep apnea syndrome were measured at rest and during ergometer exercise up to 100 W. Pulmonary hypertension at rest was found in 13, and during exercise in 31 more patients. Only 8 patients with pathological pressure findings suffered from pulmonary hypertension in combination with a pulmonary or cardiac disease. In the other 36 patients, no indication of a primary cause of pulmonary hypertension apart from sleep apnea syndrome could be found. Out of the 65 patients, 11 with a finding of more than 20 apnea episodes per hour's sleep underwent polysomnographic recordings in the sleep laboratory. The hemodynamic parameters were continuously measured. All 11 patients had a finding of severe sleep apnea with more than 300 apnea episodes during the night of recording. In 6 patients, the appearance of apnea episodes was accompanied by only moderate changes in pulmonary artery pressure. In 5 patients, there were critical increases in pulmonary artery pressure, which went along with increases in cardiac output and in pulmonary capillary wedge pressure. Increases in pulmonary vascular resistance were established in 3 out of these 5 patients, and a slight decrease in 2. The mechanism of hypoxic vasoconstriction of the pulmonary arteries may account for the pressure increases in 3 of our patients, but fails to explain the findings in the other 2 patients. Nocturnal changes in pulmonary artery pressure in patients with sleep apnea may therefore have different causes. Pulmonary hypertension constitutes a severe complication in patients with sleep apnea.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1986

Chemistry and pharmacology of SMS 201-995, a long-acting octapeptide analogue of somatostatin.

Starting from a hypothetical conformation of natural somatostatin and a knowledge of the minimal fragment needed for biological activity, a process of rational design and lead optimization has led to the potent, selective, and long-acting analogue SMS 201-995, (formula: see text) which selectively inhibits growth hormone secretion in several animal species for up to 6 h after subcutaneous application. In the rat, SMS inhibits GH, insulin, and glucagon 70, 3, and 23 times more potently than SRIF, resulting in GH/insulin and GH/glucagon selectivities of 20 and 3, respectively. The compound has been shown to inhibit growth of transplantable insulinomas in hamsters and to label selectively a subset of somatostatin receptors in the rat cortex. A radioactively labelled analogue has been used to visualize somatostatin receptors in a GRF-secreting human tumour. The stability and duration of action of SMS 201-995 after subcutaneous injection enable for the first time extended investigations of the clinical utility of somatostatin in various diseases.

Animals↗
PubMed1985

[Bronchoalveolar immunoglobulins in sarcoidosis].

In 9 patients with active and 10 patients with inactive sarcoidosis, and in 6 normal controls, the concentration of IgM, IgA and IgG broncho-alveolar lavage (BAL) fluid was measured. Patients with active sarcoidosis showed significantly higher values of these immunoglobulins than patients with inactive sarcoidosis or normals. In addition, a significant correlation between the immunoglobulin levels and the number of helper-T lymphocytes in the BAL fluid was demonstrated.

Bronchi↗
PubMed1985

T-lymphocyte subsets and immunoglobulin concentrations in bronchoalveolar lavage of patients with sarcoidosis and high and low intensity alveolitis.

Reproducible volumes of bronchoalveolar lavage (BAL) fluid were recovered from 19 patients with pulmonary sarcoidosis and from 6 control subjects using a standardized technique. Studies of cell surface markers showed that BAL from 9 patients contained more than 8 X 10(6) helper T-cells. These patients were classified as having high intensity alveolitis, whereas in 10 patients with lower cell counts, low intensity alveolitis was diagnosed. Activated helper T-cells coexpressing Leu-3a and Ia-antigens were significantly more numerous in BAL from patients with high intensity alveolitis than in BAL from the other patients and the control subjects. Concentrations of IgM, IgA, and IgG, but not of albumin were markedly increased in BAL from patients with high intensity alveolitis when compared with the other subjects. In BAL from both patient and control groups, numbers of helper T-cells and particularly of activated helper T-cells were correlated with immunoglobulin concentrations. In 4 patients with high intensity alveolitis, prednisone-induced and spontaneous clinical improvement were paralleled by a decrease in helper and activated helper T-cells and in immunoglobulin concentrations in BAL, indicating conversion of high to low intensity disease. No change was observed in 4 patients with low intensity alveolitis.

Adult↗