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Biomedical subjects

U Krause

Publications and source records attributed to U Krause.

At least 91 records · Page 5Linked to original sources
PubMed1996

Exercise and recovery in frog muscle: metabolism of PCr, adenine nucleotides, and related compounds.

The effects of exercise (swimming), fatigue, and recovery on the intracellular pH (pHi), energy-rich phosphates, and related metabolites were studied in the gastrocnemius muscle of common frogs (Rana temporaria) at 20 degrees C. Exercise caused a rapid decrease in the content of phosphocreatine (PCr) and a corresponding increase in that of Pi. The ATP level remained virtually constant for 1 min; its precipitous decrease during the following minute was associated with a rise in the contents of inosine 5'-monophosphate (IMP) and NH4+, indicating a marked activation of AMP deaminase. Five minutes of swimming caused severe fatigue, which was correlated with decreases in muscle PCr (-85%), ATP (-42%), and pHi (-0.8 units). Recovery appeared almost complete within 2 h, and the frogs were then induced to swim again. During the initial 10 s of this second exercise, ATP synthesis was as high as in the first exercise, but the rate decreased more rapidly between 10 and 60 s, thus indicating that repeated exercise caused increased metabolic stress. IMP formation in working muscle was not strictly correlated with the pHi or the tissue contents of Pi, AMP and ADP, although from studies in vitro AMP deaminase is known to be modulated by these parameters.

Adenine Nucleotides↗
PubMed1996

Control of glycolysis in vertebrate skeletal muscle during exercise.

The gastrocnemius muscle of the frog (Rana temporaria) has a high capacity for anaerobic glycolysis from glycogen. Glycolytic metabolites and effectors of phosphofructokinase, particularly the hexose bisphosphates, were followed in muscle during exercise (swimming between 5 s and 5 min), recovery (rest for up to 2 h after 5 min of swimming), and repeated exercise (swimming for up to 60 s after 2 h of recovery). Glycogen phosphorylase and phosphofructokinase were swiftly activated with exercise. The hexose bisphosphates followed markedly different time courses. Fructose 1,6-bisphosphate was transiently increased in both exercise and repeated exercise. This appears to be an effect rather than a cause of phosphofructokinase activation. Glucose 1,6-biphosphate was accumulated only while phosphofructokinase was active and was unchanged at other times. Fructose 2,6-biphosphate showed a 10-fold transient increase on exercise in rested frogs, almost disappeared from the muscle during recovery, and did not change during repeated exercise. Fructose 2,6-biphosphate is a potent activator of phosphofructokinase in vitro under near physiological assay conditions, and it may serve this function also in vivo during exercise. Glucose 1,6-biphosphate could be an activator of phosphofructokinase in repeated exercise when fructose 2,6-biphosphate is not available.

Animals↗
PubMed1996

[Is hemithyroidectomy as standard intervention of suspicious puncture cytology justified?].

Since 1989, the operative treatment of 65 patients with suspicious fine-needle aspiration cytology of solitary thyroid nodules has been decided on individual clinical criteria such as the patient's history and morphology of the remaining thyroid tissue. Finally, 9 carcinomas were seen amongst 37 hemithyroidectomy specimens, out of 28 resected thyroid glands 2 were papillary microcarcinomas, whereas the others were benign specimens up until now. Despite a comparatively low perioperative morbidity of the hemithyroidectomy, we see thyroid resections justified in cases of suspicious cytology.

Adenocarcinoma, Follicular↗
PubMed1995

Diagnosis and prognosis of renal-cell tumors: a molecular approach.

This review discusses the impact of molecular genetics on the diagnosis and prediction of the prognosis for renal-cell tumors. Through the use of molecular techniques, it has become possible to divide renal-cell tumors into genetically and biologically well-defined entities. The new classification has many advantages over morphological ones: (1) in contrary to tumor phenotype, genetic markers are constant during tumor progression and allow a precise diagnosis; (2) genetic analysis discriminates between papillary (multiple origin) and nonpapillary renal-cell carcinomas (solitary tumors); (3) genetic analysis allows a precise diagnosis of renal adenoma; (4) the new classification system offers a genetic prognostic system; and (5) the new diagnostic-prognostic system could easily be adapted to modern detection systems such as automated sequence and fragment-length analysis, which allow a quick and correct diagnosis with a high throughput.

Adenocarcinoma↗
PubMed1995

A new technique for reconstruction of the common bile duct after severe injury by laparoscopic cholecystectomy.

Laparoscopic cholecystectomy involves a higher incidence of severe common bile duct injury than did open cholecystectomy. The severe injuries most often result from technical problems and inadequate exposure. Reconstruction of the bile duct is then possible provided that an immediate diagnosis is made and an appropriate surgical technique is applied. The report focuses on a new method of reconstruction of the common bile duct by interposition of a small jejunal conduit. The procedure was performed in five patients with severe bile duct injury (Bismuth class 3-4) that occurred during laparoscopic cholecystectomy. The outcome after follow-up periods of 9 months to more than 2 years is promising. This method of reconstruction is therefore recommended for severe forms of bile duct injury.

Adult↗
PubMed1995

Pharmacokinetics of two different delivery regimens of doxorubicin in isolated hyperthermic limb perfusion.

Evaluation of doxorubicin (DOX) pharmacokinetics in hyperthermic isolated limb perfusion (HILP) is limited. In this study two administration regimens of DOX were compared in terms of area under the time concentration curve (AUC) in plasma. HILP was performed in 13 dogs. In group 1 (n = 7) four single doses of DOX were injected in intervals of 15 minutes, in group 2 (n = 6) DOX was administered continuously during the first 30 min. The total dose in both groups was 1 mg/kg body weight, and the perfusion lasted 60 min. Concentrations of DOX and its major metabolite doxorubicinol (DOXol) were measured in perfusate and muscle tissue by high performance liquid chromatography (HPLC). Pharmacokinetic estimates were calculated. The two investigated administration modes provided sufficient drug levels of DOX during the whole perfusion time. Maximum concentrations in the perfusate and areas under the time concentration curves were nearly the same. The tissue concentrations also did not show significant differences. Both regimens are practicable avoiding high peak levels of the drug in order to minimize toxic side effects.

Animals↗
PubMed1995

[Simultaneous interventions of the thyroid gland in primary hyperparathyroidism (pHPT)].

Among 334 neck explorations for primary hyperparathyroidism (pHPT) between 1979 and 1993 120 (33.9%) thyroid operations were performed simultaneously. Histologic examination revealed 40 thyroid adenomas, 43 nodular goiters, 8 thyroiditis and 9 differentiated carcinomas. In 20 cases the indication was doubtful retrospectively, as evaluated by postoperative histology. Of the 9 carcinomas there were 4 small papillary, 3 papillary pT2 No Mo and 2 follicular pT2 No Mo. Perioperative morbidity of the simultaneous operations was not significantly increased compared to the parathyroid exploration alone. We conclude, that pre- and intraoperative thyroid examination should be performed in pHPT and decision for a simultaneous operation should be made generously.

Adenocarcinoma, Follicular↗
PubMed1995

[Dorsal retroperitoneoscopic adrenalectomy--a new surgical technique].

For the first time the surgical technique of right and left adrenalectomy by a posterior percutaneous retroperitoneoscopic access is described. The adrenal gland is mobilized after creation of a pneumoretroperitoneum and insertion of 3-4 trocars beneath the 12th rip. Indications for this new method are small, benign adrenal tumours or adrenocortical hyperplasias. By this method, the potential advantages of a posterior approach and minimally-invasive surgery are combined. This surgical technique might become a major advancement in adrenal surgery.

Adrenal Cortex↗
PubMed1994

Corticotropin-releasing hormone (CRH) is a respiratory stimulant in humans: a comparative study of human and ovine CRH.

Previous experimental and clinical studies clearly demonstrated that exogenously administered CRH possesses respiratory properties. Until now, these effects were investigated using human (h) CRH in both healthy volunteers and patients under long-term respiration. We now compared the effects of hCRH with those of ovine (o) CRH in ten healthy young males. In particular it should be evaluated whether oCRH with its longer plasma half-life induces a more profound respiratory stimulation. On two separate days within two weeks, ventilation and cardiac performance were measured during steady state conditions by using a computerized cardio-pulmonary exercise testing system. In this placebo controlled double-blind-crossover study h- and oCRH (100 ug i.v. each) both augmented minute volume significantly during the observation period. Heart rate also increased after both analogues. All effects were comparable without a significant difference between both substances. There were no major side effects observable. Our data thus demonstrate that both analogues might be suitable for both diagnostic (i.e., testing of respiratory and autonomic responses) and therapeutic purposes.

Adrenocorticotropic Hormone↗
PubMed1994

[Laparoscopic Kader fistula].

A laparoscopic modification of a gastrostomy by a catheter following the method first described by Kader is presented. Characteristic features are large luminal catheters being introduced into the stomach over a guide-wire and a special trocar under laparoscopic control. The gastric wall is additionally attached to the abdominal wall by laparoscopically applied sutures. Advantages and disadvantages of the presented method are compared and discussed to alternative and established procedures.

Catheters, Indwelling↗
PubMed1994

[Results of transgenicular amputation with dorsal skin-muscle flap-plasty in patients in the final stage of arterial occlusive disease].

A modified technique of knee joint disarticulation by using a dorsal musculocutaneous flap of the gastrocnemius muscle was first described in 1985. The retrospective operative results in 60 patients with gangrene due to peripheral vascular disease (mean age 69 +/- 12 [43-93] years, 29 female, 31 male) with 62 knee disarticulations are reported. After a mean survival period of 18 (1-53) months 47% (n = 28) of the patients had died due to cardiopulmonal reasons after a mean follow-up period of 26 (3-71) months. In-hospital 48 day-lethality was 10%. 9 patients (15%) were re-amputated at above-knee level and in 5 patients operative revisions of the soft tissue were performed. After discharge from hospital 29 of 54 patients (54%) were able to walk with the aid of a prosthesis. We conclude that knee disarticulation with the use of a myocutaneous gastrocnemius flap is a safe and functionally acceptable operative method in high-risk vascular patients.

Adult↗
PubMed1994

[Combined interventions in heart and thyroid surgery--an example of interdisciplinary cooperation].

The anatomic closeness of heart and thyroid gland makes it feasible to operate on both organs simultaneously if required. Between January 1988 and February 1994 we did simultaneous procedures on heart and thyroid gland in 14 patients. We did not see any procedure-specific complications. The cumulative risk of the combined operation seems to be less than in the two stage procedure, because of the better exposure of the thyroid. The main advantage for the patient is the avoidance of a second intervention. Because of the high frequency of thyroid diseases liable for operation endocrinological diagnostics should be performed in all patients undergoing cardiac surgery. The indication for a simultaneous intervention should be made generously in order to avoid a second operation.

Adenoma↗
PubMed1993

Effects of nitrendipine on blood pressure, renin-angiotensin-system and atrial natriuretic peptide in hypertensive type I diabetic patients.

In this study, the effects of a six week treatment with the calcium channel blocking agent nitrendipine were assessed in 20 hypertensive type I diabetic patients who received a single oral dose of 20 mg daily. Plasma concentrations of atrial natriuretic peptide (ANP), plasma renin activity (PRA) and active renin, aldosterone, glycosylated hemoglobin (HbA1) and fructosamines were determined at the beginning and the end of the study. Interactions of these endocrine parameters with blood pressure behaviour were analyzed by a correlation matrix. In response to the drug treatment, the blood pressure was significantly lowered from 158.0/97.2 to 145.7/88.2 mmHg. The plasma concentrations of ANP were also significantly reduced from 106.8 to 89.7 pg/ml. There were no changes in serum aldosterone, while PRA and active renin exhibited a significant increase following the six week treatment. HbA1 and fructosamines remained unaltered. There were no significant correlations for ANP and blood pressure values, as well as for ANP and PRA or aldosterone. We did find, however, a significant correlation of the ANP values with the difference of the systolic blood pressure levels pre- and post-treatment. These data fully confirm the blood pressure lowering properties of this calcium channel blocker and its possible interference with steroidogenesis, since the effects of increased PRA on aldosterone secretion were clearly blunted. The lowering of plasma ANP levels may represent a decreased ANP secretion due to calcium channel blockade or might also be due to the natriuretic effects of nitrendipine, thus allowing ANP levels to decline as a function of lessened sodium retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Duplex ultrasound evaluation of Basedow struma treated with iodine therapy].

Over a period of 18 months the thyroid gland of 31 patients suffering from Grave's disease was examined by Duplex ultrasound for changes in blood perfusion. In 24 of these patients a follow-up study was achieved immediately after a presurgical iodine therapy. For estimation of the perfusion the "Pulsatile Flow Index (PFI)" was calculated. Compared to the normal group (22 volunteers, mean: 0.46 +/- 0.11) changes of 41 and 22% were highly significant for this pre (mean: 0.65 +/- 0.08, p < 10E-6) and post therapy (0.56 +/- 0.1, p < 5E-5). Therapy was unsuccessful in 3 cases on a single, in one case on both sides. Altogether PFI yielded semiquantitative information on blood perfusion of the gland as well as on the rate of success.

Adolescent↗
PubMed1992

Effects of insulin-like growth factor I on the rates of glucose transport and utilization in rat skeletal muscle in vitro.

1. The effects of insulin-like growth factor I (IGF-I) on the rates of glucose transport and utilization and its interaction with insulin were investigated in rat soleus muscle in vitro. IGF-I increased the rates of glucose transport, lactate formation, glycogen synthesis and the flux of glucose to hexose monophosphate, but it had no effect on the rate of glucose oxidation or glycogenolysis. 2. In the absence of insulin, low levels of IGF-I (0-30 ng/ml) increased the rate of glycolysis and the content of fructose 2,6-bisphosphate, but the content of glucose 6-phosphate remained unaltered; at higher levels of IGF-I (300-3000 ng/ml) the rate of glycolysis and the content of fructose 2,6-bisphosphate showed a further modest increase, but the content of glucose 6-phosphate doubled. Similar changes were seen when the level of insulin was increased from basal (0-0.4 ng/ml) to maximal (40 ng/ml). 3. Neither IGF-I nor insulin affected the contents of ATP, ADP, AMP, phosphocreatine or citrate. 4. Maximal concentrations of IGF-I increased the rate of lactate formation to a greater extent than did maximal concentrations of insulin. 5. In the presence of IGF-I, the rate of glucose utilization was less responsive to insulin. 6. The results suggest that, in rat skeletal muscle: (a) IGF-I increases the rates of glucose transport and utilization independently of insulin, and has a preferential effect on the rate of lactate formation; (b) the effects of IGF-I and insulin are not additive; (c) in addition to its effects on glucose transport, IGF-I increases the rate of glycogen synthesis and may stimulate glycolysis at the level of 6-phosphofructokinase; (d) changes in the content of fructose 2,6-bisphosphate may be part of the mechanism to regulate glycolytic flux in skeletal muscle in response to either IGF-I or insulin.

Animals↗