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Biomedical subjects

G Wegener

Publications and source records attributed to G Wegener.

At least 55 records · Page 3Linked to original sources
PubMed1990

Fructose 2,6-bisphosphate and glycolytic flux in skeletal muscle of swimming frog.

Glycolytic flux in skeletal muscle is controlled by 6-phosphofructokinase but how this is achieved is controversial. Brief exercise (swimming) in frogs caused a dramatic increase in the phosphofructokinase activator, fructose 2,6-bisphosphate, in working muscle. The kinetics of phosphofructokinase suggest that in resting muscle, the enzyme is inhibited by ATP plus citrate and that the increase in fructose 2,6-bisphosphate is part of the mechanism to activate phosphofructokinase when exercise begins. When exercise was sustained, fructose 2,6-bisphosphate in muscle was decreased as was the rate of lactate accumulation. Glycolytic flux and the content of fructose 2,6-bisphosphate appear to be closely correlated in working frog muscle in vivo.

Animals↗
PubMed1990

[Radical surgical intervention with conventional radiation versus multimodality therapy protocol in undifferentiated thyroid cancer].

Out of a total of 550 patients with thyroid cancer diagnosed over the 16-year period 1972-June 1989, 44 showed undifferentiated carcinoma and were treated by thyreoidectomy and early postoperative external irradiation. In order to analyse the outcome in patients treated by primary surgery in contrast to patients treated by means of a multimodal therapy concept we compared our surgical procedures with regard to primary surgical approach, early postoperative course, operative complications and survival to the data on the multimodal therapy concept of the Karolinska Hospital reported by E. Tallroth et al. 1987. A significantly better survival was correlated with radical (n = 20) versus palliative tumour resection (n = 24) (p less than 0.001), and total thyroidectomy (n = 25) versus subtotal thyroidectomy (n = 19) (p less than 0.006). Radical surgery with early postoperative external irradiation revealed no postoperative mortality and no symptomatic cervical tumour recurrence. By contrast, palliative surgery, particularly in the case of synchronous tracheotomy, was attended by a relatively high mortality (29%) and symptomatic local recurrences. The results of this study suggest that in undifferentiated thyroid carcinoma an attempt at radical tumour resection should be undertaken, since multimodal therapy procedures revealed a significantly highly complication rate (up to 36%) and, in comparison with a radical surgical treatment policy, showed a higher rate of local recurrences (0% vs. 48%) and a lower survival (mean survival 42 vs. 15 months).

Aged↗
PubMed1990

Bronchoscopy in severe blunt chest trauma.

Extended lesions of the lung parenchyma are often seen in association with blunt chest trauma. Blood aspiration, atelectasis and the formation of bronchopleural fistulae can lead to early respiratory deterioration and the development of severe post-traumatic complications (pneumonia, acute respiratory distress syndrome). Diagnostic and therapeutic bronchoscopy is essential on admission. This procedure helps to estimate the severity and extent of parenchymal lesions even before chest X-ray signs are noted. Bronchoalveolar lavage is needed for removal of aspirates. In our study bronchoalveolar lavage on admission reduced bacterial contamination and pneumonia in comparison to patients not lavaged. A new method for closure of bronchopleural fistulae is described. Fibrin instillation after balloon catheter occlusion leads to a significant reduction of tidal volume loss (greater than 50% in average).

Adult↗
PubMed1990

Glycogen phosphorylase in fish muscle: demonstration of three interconvertible forms.

White skeletal muscle of crucian carp contains a single isoenzyme of glycogen phosphorylase, which was purified approximately 300-fold to a specific activity of approximately 13 mumol.min-1.mg protein-1 (assayed in the direction of glycogen breakdown at 25 degrees C). Tissue extracts of crucian muscle produced three distinct peaks of phosphorylase activity when separated on DEAE-Sephacel. Peaks 1 and 3 were identified, in terms of kinetic properties and by interconversion experiments, as phosphorylase b and a, respectively. Peak 2 was shown to be a phospho-dephospho hybrid. The three interconvertible forms of phosphorylase were purified and shown to be dimeric molecules at 20 degrees C. At 5 degrees C, a and the hybrid tended to form tetramers. The Mr of the subunit was estimated to be 96,400 from sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The hybrid is kinetically homogeneous, and its kinetic properties are intermediate between those of b and a forms. The b, hybrid, and a forms of phosphorylase can be isolated from rapidly frozen muscle of crucian but in different proportions, depending on whether fish were anesthetized or forced to muscular activity for 20 s. Muscle of anesthetized crucian had 36, 36, and 28% of phosphorylase b, hybrid, and a forms, respectively, whereas the corresponding values for exercised fish were 12, 37, and 51%. Results suggest that three interconvertible forms of phosphorylase exist simultaneously in crucian muscle and that hybrid phosphorylase is active in contracting muscle in vivo.

Anesthesia, General↗
PubMed1990

[Undifferentiated thyroid cancer: improved therapeutic results following initial radical intervention and early postoperative radiotherapy].

During a 16-year period (1972-1988), 40 out of 477 thyroid cancer patients underwent thyroidectomy for undifferentiated thyroid carcinoma. To analyse the significance of "radical" versus "palliative" surgical procedures with regard to early postoperative course, operative complications and survival, all patients records were reviewed and actually followed up. A significant better survival was correlated with radical (n = 17) versus palliative tumor resection (n = 23) (p less than 0.001), and total thyroidectomy (n = 22) versus subtotal thyroidectomy (n = 18) (p less than 0.006). Radical surgery with early postoperative external irradiation revealed no postoperative mortality and only one symptomatic cervical tumor recurrence. In contrast, palliative surgery, particularly in the case of synchronous tracheotomy, was attended with a relatively high mortality (30%) and symptomatic local recurrences. The results of this study suggest that in undifferentiated thyroid carcinoma without infiltration of the esophageal or tracheal mucosa an attempt of radical tumor resection should be undertaken, since palliative surgical procedures revealed a significantly lower survival due to complications of persistent or recurrent cervical tumor infiltration and frequently were accompanied by local complications during the postoperative course.

Aged↗
PubMed1986

Antagonistic effects of hexose 1,6-bisphosphates and fructose 2,6-bisphosphate on the activity of 6-phosphofructokinase purified from honey-bee flight muscle.

6-Phosphofructokinase purified from honey-bee flight muscle is inhibited by ATP and, unusually, by glucose 1,6-bisphosphate and fructose 1,6-bisphosphate. The inhibition by either of the bisphosphates is not relieved by AMP, but is relieved by fructose 6-phosphate and especially by fructose 2,6-bisphosphate. Lack of effect by AMP is consistent with a low activity of adenylate kinase in this muscle.

Adenosine Triphosphate↗
PubMed1985

Effects of cold adaptation and starvation on sciatic nerve fibers in the frog.

The conditions under which frogs are kept prior to experimentation were found to have a measurable effect on peripheral nerve structure. Frogs kept for 12 weeks at 4 degree C had markedly shrunken sciatic nerve fibers compared with frogs kept at 19 degrees C. Intermediate fiber shrinkage was found for frogs kept at 19 degrees C without feeding. Counts of neurofilaments and microtubules showed that fiber shrinkage was from a preferential loss of filaments, indicating cold- or starvation-induced atrophy of the axon's cyto-skeleton. This effect, however, was superimposed with additional osmotic axonal shrinkage, causing filament densities to increase per area. There were no changes in myelin sheath thickness due to cold adaptation or fasting.

Adaptation, Physiological↗
PubMed1984

Age affects the metabolic rate of insect brain.

Brains of adult insects can be isolated and studied in vitro. In female blowflies the oxygen uptake of the brain is age dependent. A steady increase is followed by a precipitous decrease around the middle of the little span. These changes are accompanied by alterations of mitochondrial structure and deposits of lipofuscin-like material.

Aging↗
PubMed1982

The median ventricular formation. A distinct structure at the mesencephalic apex.

The prenatal ontogenesis of the median ventricular formation (MVF)--a cell group at the seam between both sides of the mesencephalic roof--was analyzed ultrastructurally, autoradiographically and for the expression of intracytoplasmatic structures, i.e. glial filament antigen. As compared with other regions of the mesencephalic roof it was found that from embryonal day 12 onwards DNA synthesis of ventricular cells in the dorsal midline is significantly reduced. This reduction is more pronounced at later developmental stages. On the other hand, the MVF gains drastically in width during ontogenesis. It was shown that this increase may be caused by an immigration of postmitotic neighbouring ventricular cells. The characteristic morphological feature of MVF cells is their extension from the ventricular lining to the pial basement membrane. Their dorsal processes are joined to a thin fibre bundle and predominantly display microtubules as well as filaments and glycogen within their electrolucent cytoplasm. They also contain intracellular structures that react with antibodies against glial filaments as revealed by an enzyme-coupled immunolabelling. The perikarya of MVF cells, on the other hand, are almost all situated at the same level within the ventral third of the mesencephalic roof, thus bulging concentrically at the lateral sides of the MVF. Characteristically, a subfraction of MVF cells exhibits vast amounts of rough ER. The nature and function of the MVF cells is discussed in the light of the concept of guidance of preneurons by radial glia (Sidman and Rakic 1973).

Animals↗
PubMed1979

[Comparison of the effects of lofepramin and mianserin in depressed patients in a double blind trial].

The therapeutic efficacy of two newly developed anti-depressants lofepramine and mianserin was compared in a double-blind clinical trial in 30 depressed inpatients. During the treatment period of 4 weeks the depressive symptoms assessed by the Hamilton Rating Scale for Depression decreased in both groups. In this trial a stronger influence of lofepramine on the factor 'retarded depression' could be demonstrated (p = 0.08). In addition lofepramine showed a significantly better reduction of anxious reactions than mianserin (p less than 0.01). Concerning tolerance, no difference between the two drugs was observed.

Adult↗