Search PubMed⌕ Search

Biomedical subjects

M Fischer

Publications and source records attributed to M Fischer.

At least 451 records · Page 25Linked to original sources
PubMed1992

[Functional protein S in 77 patients treated with anticoagulants and in 32 probands with normal coagulation parameters].

We determined functional protein S with a new automated clotting assay, total protein S antigen with the Laurell technique and free protein S antigen with an ELISA test and calculated the ratio of total protein S antigen and prothrombin antigen (Laurell) of plasmas of 77 patients oral anticoagulant therapy and of 32 normals. The correlation of total protein S antigen with protein S activity was found to be r = 0.857. The normal range of the tests was calculated for orally anticoagulated patients and for normals and was compared with the analytical data from 4 orally anticoagulated, congenital protein S deficiency patients. We believe that the automated functional protein S clotting assay is a quick and easily performed test, which now allows even for protein S the use of a functional assay as the first step for the screening of coagulation inhibitor deficiencies.

Arterial Occlusive Diseases↗
PubMed1992

Mechanisms of interhemispheric transfer and patterns of cognitive function in acallosal patients of normal intelligence.

We investigated interhemispheric transfer and cognitive function in two boys with normal intelligence in whom agenesis of the corpus callosum was identified following minor head trauma. In patient 1, magnetic resonance imaging scan showed agenesis of the corpus callosum and absent anterior commissure. Results of visual interhemispheric transfer tasks suggested degradation in transfer of information to the left hemisphere. Results of a tactile interhemispheric transfer task suggested degradation of access to the right hemisphere. In patient 2, magnetic resonance imaging scan showed agenesis of the corpus callosum and enlarged anterior commissure. Results for both visual and tactile interhemispheric transfer tasks were normal. Dichotic listening tests showed a slight left ear advantage in both patients. These results support the hypothesis that hypertrophy of the anterior commissure is an important mechanism of functional compensation in agenesis of the corpus callosum. However, the relative subtlety of deficits in patient 1 and results of dichotic listening tests support use of other mechanisms as well. No consistent pattern of cognitive deficits was observed.

Agenesis of Corpus Callosum↗
PubMed1992

Electron microscopy analysis of mineral fibers in human lung tissue.

In the present study, lung samples from 126 autopsied cases were examined to determine the content of mineral fibers using analytical transmission electron microscopy (ATEM). The cases were divided into four groups (22 lungs of persons exposed to ambient environmental pollution, 32 cases of mesothelioma, 38 cases of primary lung cancer, and 34 asbestosis cases, 13 of these with additional pleural plaques). Fibers were counted, measured, and mineralogically identified using a combination of X-ray microanalysis and electron diffraction of the non-oriented fiber. Concentration of fibrous particles (defined as particles above 1 micron in length with roughly parallel long sides and an aspect ratio of 5:1 and greater) was calculated as fibers 10(6)/g dry lung weight. The concentration of chrysotile was found to be similar throughout the groups except for two cases in the asbestosis group with comparably high numbers of chrysotile. However, a remarkable difference for amphiboles could be observed between the groups. Asbestos bodies were mostly found in the asbestosis group. There was a rather good correlation between numbers of amphibole fibers and asbestos bodies, with an average ratio of 10:1. For comparison purposes between occupationally exposed/non-exposed individuals, a transition was found in the concentration range of 3-10(7) asbestos fibers/g dried lung weight.

Analysis of Variance↗
PubMed1992

Effects of combined renovascular hypertension and diabetes mellitus on myocardial cells, non-vascular interstitium and capillaries: a stereological study on rat hearts.

The effects of combined renovascular hypertension and diabetes mellitus on the rat heart were investigated in order to detect possible synergistic effects of the two conditions. Hypertensive diabetic and hypertensive non-diabetic animals were compared to diabetic and non-diabetic controls. Hypertension was established for 12 weeks by a surgical stenosis of the left renal artery; diabetes mellitus was maintained for 8 weeks by a single intraperitoneal injection of 60 mg/kg streptozotocin. Light microscopic stereology did not reveal significant divergences between diabetic hypertensives and non-diabetic hypertensives. Hypertension induced a focal perivascular and interstitial fibrosis with increased volume densities of non-vascular interstitium and fibrosis (P less than 0.001). Capillary density (QA) was decreased in transverse sections (P less than 0.01) and increased in longitudinal sections (P less than 0.01). This indicates a three-dimensional remodelling of the capillary bed with an increased number of obliquely running capillaries. At least the length density (LV) of capillaries (mm/mm3) tends to be normalized in long-term renovascular hypertension. At the ultrastructural level, a synergism of hypertension and diabetes mellitus was observed: the volume ratio of mitochondria to myofibrils was significantly decreased in hypertensive diabetics, but not in non-diabetic hypertensives or in diabetics. This may enhance the risk of cardiac deterioration. We conclude that the primary target of the synergistic damage in hypertensive diabetic heart muscle disease is the myocardial cell and not the cardiac interstitium.

Animals↗
PubMed1992

Cortisol levels and vigilance in eating disorder patients.

Elevated plasma levels of cortisol, as well as deficits in cognitive processes such as attention, have been observed in patients with eating disorders. The association between plasma cortisol and performance in vigilance task was studied in 17 patients with bulimia nervosa or anorexia nervosa during the acute phase of their eating disorder. In comparison to normal young women, the patients had a significantly lower hit rate in a discrimination task and showed an impaired perceptual sensitivity index. They also displayed significantly longer reaction times to hits, but not to false alarms. Cortisol levels of the patients were significantly higher than those of the normal controls. When patients were divided according to their median cortisol level, the patients with higher levels performed significantly more poorly than did the patients with lower levels. In the total patient sample, cortisol levels showed a significant negative correlation with hit-rate (r = -.54) and a significant positive correlation with reaction time to hits (r = .70). Other clinical characteristics were not related to cognitive performance. These results suggest a possible role of cortisol in the development of attentional deficits in eating disorder patients.

Adult↗
PubMed1992

Ultrasonographic evaluation of Legg-Calve-Perthes disease based on sonoanatomic criteria and the application of new measuring techniques.

This study attempts an ultrasonographic classification of Legg-Calve-Perthes disease according to sonoanatomic and sonometric criteria. Four stages, similar to standard radiological staging, could reproducibly be found in 29 patients with unilateral disease. The stages could be significantly differentiated according to descriptive sonoanatomic criteria and partially newly introduced sonographic measurements, including epiphysis-metaphysis-index and acetabulum-epiphysis-distance. Sonographic evaluation of Perthes hips is a simple and standardised procedure, which can serve to stage and monitor the course of the disease and hence reduce the amount of X-ray exposure and treatment costs.

Child↗
PubMed1992

Comparative analysis of native and cysteine-deficient HIV-1 reverse transcriptase.

To study the subunit structure and the active site of human immunodeficiency virus reverse transcriptase (RT), the enzyme was expressed in E. coli and purified to homogeneity in large quantities. The recombinant enzyme consists of two major polypeptides of 66,000 and 53,000 Da in equimolar amounts and a minor species of 51,000 Da. Amino acid sequence analysis of the recombinant proteins revealed that the amino termini of the two major subunits are identical to that of the virion-derived enzyme. The two cysteinyl residues at positions 38 and 280 in the RT amino acid sequence were replaced by alanine in an attempt to elucidate the role of the sulfhydryl groups in RT enzyme activities, heterodimer formation, and intrasubunit linkage. The results reported here show that the two cysteinyls are dispensable and their absence in the amino acid sequence of the reverse transcriptase does not affect DNA polymerase or ribonuclease H enzyme activities or the formation of heterodimer structures. Furthermore, inhibitors of polymerase activity such as 3-azidothymidine triphosphate, dideoxythymidine triphosphate, and tetrahydroimidazo[4,5,1-JK][1,4]benzodiazepens (1H)-one are equally effective on the mutant containing no cysteinyl residues and the wild-type enzyme.

Base Sequence↗
PubMed1992

Fat elimination in acute renal failure: long-chain vs medium-chain triglycerides.

Elimination and hydrolysis of fat emulsions containing long-chain (LCT; Intralipid) or long- and medium-chain triglycerides (MCT; Lipofundin MCT) were compared in seven patients with acute renal failure (ARF) and six healthy control subjects. In control subjects, clearance of MCT was slightly higher than that of LCT (1.93 +/- 0.34 vs 1.55 +/- 0.3 mL.kg body wt-1.min-1, P less than 0.05). The rise in plasma triglycerides was similar and the release of free fatty acids was higher during MCT (P less than 0.02). In ARF, clearance of both LCT and MCT was equally reduced (0.53 +/- 0.12 vs 0.59 +/- 0.14 mL.kg body wt-1.min-1, P less than 0.01 vs control subjects). Again, the rise in triglycerides was comparable. Free fatty acid release was higher during MCT but lower than in control subjects. Plasma concentrations of glucose and lactate were not affected in control subjects but increased during both LCT and MCT in ARF. Thus elimination of both LCT and MCT is profoundly decreased in ARF. The impaired lipolysis in ARF cannot be circumvented by the use of MCT.

Acute Kidney Injury↗
PubMed1992

Healing and relapse of duodenal ulcer during ranitidine therapy in the elderly. The RUDER Study Group.

A total of 2,109 outpatients with active duodenal ulcer (DU) entered an open, prospective study in order to investigate factors influencing healing and relapse during 2 years of ranitidine therapy (300 mg daily for healing, 150 mg as maintenance treatment). In a retrospective analysis, we evaluated the influence of age. Symptoms related to DU in 1,899 evaluable cases in patients over 65 years of age (n = 185) were identical to those of DU patients younger than 65 years old (n = 1,714). Rapid healing within 2 weeks of ranitidine therapy was less frequent in the elderly (32.5%) than in younger patients (40.7%) though identical healing rates (94.1%) in each group were achieved by continuation of ranitidine therapy for 8 weeks. Cumulative recurrence rates during the 2 years of long-term therapy were lower (17.3%) in old age than in patients under 65 years of age (23.3%). Adverse events were rare in both age groups. We conclude that DU healing during ranitidine is delayed in old age. Additional differences in relapse rates in favor of the elderly suggest that DU disease has a different course in the elderly.

Adult↗
PubMed1992

Endoscopic implantation of collagen (GAX) for the treatment of urinary incontinence.

Sixteen women whose ages ranged from 42 to 73 years (mean 57) and 2 men, aged 76 and 80 years respectively, were treated for urinary stress incontinence with transurethral implantation of submucosal glutaraldehyde cross-linked collagen (GAX); 15 females had had several continence operations previously and 1 female was totally incontinent following low anterior resection of the sigmoid colon for cancer. All but 2 patients received 8 ml GAX in a single operative session under general anaesthesia. Before implantation, patients underwent urodynamic evaluation, cystoscopy, urinary stress test and the two-thirds capacity pad weighing test. Post-operative evaluations were carried out after 3, 6 and 9 months and included urinary flow rate, urine analysis, residual urine determination and the two-thirds pad weighing test. The results were encouraging. After 3 months, 8/18 patients were cured, 7/18 had improved and 3/18 had failed to respond. Nine months post-operatively, 7 patients were still continent, 8 had improved and 3 remained unchanged. One of the improved group had a reinjection 18 months post-operatively and has been continent since then. We feel that GAX collagen injection is a safe and easy method for the treatment of urinary stress incontinence; it has no observable or measurable morbidity.

Adult↗
PubMed1992

Regulation of intestinal lactase in adult hypolactasia.

Relative deficiency of intestinal lactase activity during adulthood, adult hypolactasia, is a common condition worldwide. We studied the regulation of lactase-phlorizin hydrolase in normal and adult hypolactasic subjects by correlating transcript abundance in intestinal biopsies with relative synthetic rates for the protein in cultured intestinal explants. After metabolic labelling studies in six subjects, precursor lactase-phlorizin hydrolase was identified in amounts directly proportional to the enzyme-specific activity suggesting that levels of intestinal lactase are regulated by synthetic rate. Total intestinal RNA was extracted from biopsies of these subjects and three hypolactasic adults who had participated in previous biosynthesis studies. Transcript levels were markedly reduced in deficient subjects who demonstrated diminished lactase-phlorizin hydrolase synthesis. The sequence of 1 kb of 5'-flanking region of the lactase-phlorizin hydrolase gene was determined in two hypolactasic subjects and two controls. No sequence variability was identified to account for differences in mRNA levels or biosynthetic rates between the two groups. A single hypolactasic subject previously characterized as demonstrating delayed posttranslational processing, showed message levels intermediate between other deficients and controls. These results suggest that in the majority of our subjects, pretranslational mechanisms account for the predominate regulatory control of lactase-phlorizin hydrolase expression in the proximal intestine.

Adult↗
PubMed1992

Influence of stress on the healing and relapse of duodenal ulcers. A prospective, multicenter trial of 2109 patients with recurrent duodenal ulceration treated with ranitidine. RUDER Study Group.

The influence of psychologic factors on the healing and relapse of duodenal ulcers under treatment with ranitidine was studied in a prospective, multicenter trial in 2109 patients with an endoscopically proven duodenal ulcer (DU) and a history of recurrent duodenal ulceration. All patient received ranitidine (300 mg daily), and, after healing, 1899 patients continued maintenance treatment (ranitidine, 150 mg daily) for 2 years. A physician's assessment of stress (stress or no stress) was made at every consultation. In the healing phase an overall classification of stress as absent, intermittent, or continuous was made, and in the maintenance phase patients were classified dichotomously as having stress (stress on at least half of the follow-up consultations) or no stress. In addition, at the start of the healing phase stress was measured by means of a standardized questionnaire. Continuous stress, as assessed by the physicians, was associated with a lower 14-day healing rate (35.7%) than intermittent or absent stress (42.4%; relative risk (RR) for delayed healing in patients with continuous stress, 1.19; 95% confidence interval (CI), 1.06-1.33; P < 0.02). Differences in the 14-day healing rate for patients with low and moderate stress scores (43.1%) compared with those with high and very high stress scores (37.9%) just failed to reach statistical significance (RR for patients with stress, 1.14; 95% CI, 0.998-1.29; P = 0.051). During the 1st year of maintenance treatment 18.3% of patients with stress, but 10.9% of patients without stress, had a DU relapse (RR of stress for DU relapse during the first year, 1.73; 95 CI, 1.44-2.09; P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Normative parameter characterization for the auditory brainstem response of the normal newborn].

The auditory brainstem response generated by clicks was studied in 119 normal newborns. One ear was studied in detail at 20, 40 and 60 dBnHL, the other at 20 and 30 dBnHL, increasing the intensity if no response was found. The latency for waves I, III and V in the detailed studied ear was 2.7 +/- .39, 5.4 +/- .44 and 7.7 +/- .48, respectively. 85% of newborns had thresholds for auditory brainstem response less than 40 dBnHL, 54% less than 20 dBnHL and 15% between 40 and 60 dBnHL. These findings are compatible with conductive loss in the higher threshold group and support data from Stockard, regarding high risk groups. Additionally, our data suggests that an adequate level to screen for hearing loss in newborns is between 30 and 40 dBnHL.

Auditory Threshold↗
PubMed1992

[Decrease of postoperative morbidity in coronary surgery using the two internal mammary arteries].

The surgical risk of bilateral internal mammary artery grafting was analyzed in 100 successive patients separated chronologically into two groups. These groups were not statistically different in terms of age, severity of angina, and extent of coronary artery disease. The number of grafts per patient and the time of aortic cross clamping were not statistically different in the two groups. The postoperative mortality was 1% in the 100 patients. The incidence of perioperative myocardial infarction was not statistically different in the two groups. No mediastinal suppuration was observed. The mean postoperative hemorrhage was 633 +/- 558 ml in the first 50 patients and 560 +/- 410 ml for the last 50 patients (p < 0.05). The percentage of patients receiving no homologous blood transfusion was 64% in the first 50 patients and 94% in the last 50 patients. The percentage of phrenic palsy was 36% in the first 50 patients and 6% in the last 50 patients (p < 0.05). With surgical experience, the risk of coronary bypass with bilateral internal mammary artery was lowered and very similar to the surgical risk of conventional aorto-coronary bypass with saphenous veins or one mammary artery.

Adult↗
PubMed1992

[Surgical indications for partial inpatient and ambulatory surgery of the lower extremities].

Outpatient (ambulatory) surgery has become widely accepted in free-standing outpatient surgery centres and in hospitals covering the field of hand surgery as well as, increasingly, the field of lower-extremity surgery. Three factors are decisive for secure ambulatory surgery: adequate material and personal resources guaranteeing a round-the-clock medical service, outpatient anesthesia which focuses mainly on the perioperative care of outpatient surgery, and a well-informed patient. Under these prerogatives the majority of surgical procedures of the lower extremities are performed on an outpatient basis without any undue risk. This includes also the diagnostic and operative arthroscopy of different joints.

Adult↗
PubMed1992

[Total intravenous anesthesia using propofol and alfentanil as compared to combined inhalation anesthesia reduces the flow velocity in the middle cerebral artery. A Doppler sonographic study].

Anesthesia for craniotomies should guarantee hemodynamic stability, preservation of cerebral autoregulation, and rapid postoperative recovery of consciousness. Increases in intracranial pressure (ICP) and postoperative respiratory depression should be avoided. Combined anesthesia (KA) with N2O and volatile anesthetics may increase cerebral blood flow (CBF), ICP, and cerebral oxygen consumption. According to recent studies, total intravenous anesthesia (TIVA) with propofol and alfentanil seems to best fulfill the requirements. Using transcranial Doppler sonography (TCD) (TC2-64, EME), we studied the influence of TIVA and KA under normo- and hyperventilation on the blood flow velocity (BFV) and pulsatility of the middle cerebral artery (MCA). METHODS. Two groups of 10 patients each undergoing craniotomy were investigated. Systolic and mean BFV, pulsatility index, mean arterial blood pressure, heart rate, and arterial CO2 tension were measured at four time intervals: (1) preoperatively; (2) 15 min after anesthesia induction under normoventilation, preoperatively; (3) 25 min after anesthesia induction under hyperventilation, preoperatively; and (4) 6 h postoperatively. The patients were premedicated with flunitrazepam 1 mg PO. TIVA was induced with 60 mg propofol, 1 mg alfentanil, and 6 mg vecuronium; simultaneously infusions of propofol (15 mg/min) and alfentanil (0.3 mg/min) were started and were maintained until the dura was completely opened. The infusion rates were then reduced to 6 mg/min propofol until skin suturing and 0.1 mg/min alfentanil until dural suturing was completed. Patients were ventilated with O2/air (fiO2 = 0.5). In the KA group anesthesia was induced with 4-6 mg/kg thiopental, 0.15 mg fentanyl, and 6 mg vecuronium and maintained with boluses of fentanyl, N2O (fiO2 = 0.5), and isoflurane (1.3 MAC). The time course is illustrated in Figs. 1 and 2 and the results are shown in Tables 1 and 2. They were tested using a one-factor analysis of variance and the Kruskal-Wallis range test. RESULTS. There was a significant decrease in systolic and mean BFV combined with an increase in pulsatility index after induction of TIVA, while KA induction effected no significant change in cerebral hemodynamics. The subsequent hyperventilation caused a similar decrease in mean BFV and increase in pulsatility index in both groups. CONCLUSION. Using the assumption that the diameter of the MCA is nearly constant, the reduction in BFV associated with an increase in pulsatility during TIVA is explainable as a decrease in CBF. By having a comparable influence on hemodynamics, the reduction in CBF with increase in cerebral vascular resistance seems to make TIVA the more advantageous anesthesia technique for patients with reduced intracranial compliance.

Adult↗