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Biomedical subjects

R Krause

Publications and source records attributed to R Krause.

At least 109 records · Page 6Linked to original sources

Venous pressure in man during weightlessness.

To determine whether the body fluid shift from the lower limbs toward the head that occurs during spaceflight leads to lasting increases of venous pressure in the upper body, venous pressure and hematocrit measurements were made on four astronauts before flight and 1 and 12 hours after recovery and compared with measurements in space. During the mission the hematocrit was elevated and the venous pressure lowered by 1 to 8 centimeters of water as compared with the preflight data. One hour after landing the hematocrit decreased, indicating a hemodilution, venous pressures were unexpectedly high, and a body weight loss of 4 to 5 percent was observed. Twelve hours later the venous pressures were the lowest recorded during the study. The fluid shift apparently takes place during the first several hours of spaceflight. Thereafter, the pressure in the peripheral veins and the central circulation is lower than that measured before flight.

Body Fluids↗

Energy replacement during parenteral nutrition in surgery, sepsis and cancer.

For many years, the increased nutritional requirements of surgical, septic and cancer patients were identified, but no effective therapy existed for averting their negative calorie and nitrogen balance. Parenteral nutrition offered an answer in many of these situations. However, abnormalities in liver function, ventilatory load, hyperglycemia and a disturbed metabolic homeostasis showed that in excessive amounts, glucose can behave as a relatively toxic substance. For cases with increased energy expenditure, new alternatives had to be devised in order to avoid excessive glucose intakes. One obvious possibility in these cases was to refrain from offering more than the basal caloric needs, until the patient had passed the period of acute injury, or other measures had effectively controlled the sepsis or cancer. Other options included the partial substitution of glucose by lipids or amino acids. Preliminary information suggests that this approach could lead to better nutritional outcome and survival rates, but additional studies are required.

Journal Article↗

Experimental investigation on the spinal cord evoked injury potential.

Averaged somatosensory evoked potentials from the epidural space in response to sciatic nerve stimulation were recorded in bipolar and common reference mode in cats following various types of injury. An investigation was conducted on the development and properties of the spinal evoked response recorded from the center of the injury site, designated here as the "spinal cord evoked injury potential." Typically it is a two-peak monophasic positive potential, approximately 40 msec in duration, with a slight negative afterwave. With increasing distance from the site of injury, its amplitude rapidly decreases, whereas latency remains constant. The common reference recording technique resulted in an earlier and better demonstration of the evoked injury potential, especially when it was transitory or incomplete. When impairment of conduction developed gradually, the evoked injury potential developed gradually too. In serial recordings along the spinal cord axis, the transition from a normal triphasic to a monophasic evoked injury potential allowed a precise localization of the lesion. These data suggest that the diagnostic value of intraoperative spinal cord monitoring may be increased by adopting a technique that incorporates several epidural recordings with a common reference recording technique. The spinal cord evoked injury potential seems to be a more sensitive indicator of spinal cord injury than the cortical evoked potential. The findings are discussed in the light of the presently developing spinal cord monitoring techniques.

Animals↗

Extracranial carotid artery aneurysms.

Carotid artery aneurysms are rare, however, serious complications may result--namely, rupture, thrombosis, or emboli. Five distinct clinical types of aneurysms are reported with different symptoms and treatment. Fusiform, saccular, false, and mycotic aneurysms are best treated with interposition autogenous vein grafting. Spontaneous dissection aneurysms are best treated initially with anticoagulation and follow-up angiography. Recanalization is the usual result. Meticulous surgical technique to prevent perioperative emboli is essential to prevent central nervous system complications.

Adult↗

Dihydrotestosterone causes reversible infertility in male rats.

Dihydrotestosterone released continuously from a subcutaneously implanted Silastic elastomer was more potent than testosterone in reducing circulating gonadotropin and androgen concentrations and in inducing testicular atrophy and infertility despite normal ejaculatory function as judged by the presence of vaginal plugs in cage mates. All effects were reversible. Thus quantities of dihydrotestosterone which reduce circulating gonadotropin concentrations suffice to maintain the weights of accessory sex organs but not spermatogenesis. That the latter is possible with higher doses even in the complete absence of luteinizing hormone and follicle-stimulating hormone (state after hypophysectomy) has been shown by others.

Animals↗

[The problem of documentation in traumatology].

An exact documentation is a necessary demand of modern medicine. Different methods of the registration of information, for example the conventional sick-paper, the punch card and the electronic data processing documentation are opposed with their pros and cons. The own experiences of the surgical hospital of the Friedrich-Schiller-University with the documentation of injured patients is shown and explained. The text points to the importance of the electronic data processing registration and evaluation of the many facts of the injured patients concerning the therapeutic, epicritical, but also epidemic and legal questions.

Accidents↗

[Morphological characterization of the islets of langerhans in metabolically healthy C57BL KsJ mice].

The islets of Langerhans of metabolic healthy C57 BL KsJ mice have been characterized morphologically. By it they showed structures typical for Muridae as far as the A-cells formed a mostly single-layered shell around the compact complex of B-cells situated centrally. The electron-microscopical investigations rendered possible a well defined differentiation between A-, B-, and D-cells and also demonstrated no fundamental structural differences in comparison with the conditions existing in other rodents.

Animals↗

Brain tryptophan and the neoplastic anorexia-cachexia syndrome.

The cause of anorexia associated with neoplasia is unknown, and some investigators have suggested a central mechanism. Recent neurophysiologic studies have revealed the possible role of serotoninergic system involving tryptophan (TRP) and its indole neurotransmitter metabolites in regulating particular aspects of feeding behavior. We therefore studied plasma and brain factors affecting TRP transport through the blood-brain barrier (plasma free and total TRP, albumin, nonesterified fatty acids, plasma neutral amino acids, brain uptake index [BUI] for TRP) and central serotonin metabolism (5-HT, 5-HIAA) in young, anorexic rats bearing the Walker-256 tumor injected intramuscularly. Plasma free TRP, but not plasma total TRP, and, more important, brain TRP and brain 5-HIAA were significantly higher in tumor-bearing rats than in pair-fed control animals. The results suggest an association between altered brain TRP metabolism and feeding behavior in tumor-related anorexia.

Animals↗