Search PubMed⌕ Search

Biomedical subjects

B Fischer

Publications and source records attributed to B Fischer.

At least 325 records · Page 18Linked to original sources
PubMed1985

Adrenergic regulation of lipolysis in abdominal adipocytes of obese subjects during caloric restriction: reversal of catecholamine action caused by relief of endogenous inhibition.

The effects of adrenaline, noradrenaline, and of the alpha 2- and beta-selective agonists clonidine and isoproterenol were studied in fifteen obese subjects before and after 4 weeks of caloric restriction (300 cal day-1). Basal glycerol release averaged 1.4 mumol (10(6) cells)-1 (180 min)-1 before starvation and 2.8 mumol (10(6) cells)-1 (180 min)-1 during starvation (P less than or equal to 0.1). Before starvation adrenaline and noradrenaline caused a 2-3-fold increase of glycerol release. This lipolytic effect disappeared during starvation. An inhibitory effect of adrenaline was observed instead which was maximal at an adrenaline concentration of 1 mumol 1(-1) (P less than or equal to 0.05). The dose-response relationships of the alpha 2- and beta-selective agents clonidine and isoproterenol were not appreciably changed by caloric restriction. The increase of basal lipolytic rate and the reversal of adrenaline action seen during caloric restriction could be mimicked by removal of endogenous adenosine using adenosine deaminase (1.6 microgram ml-1). In addition, inclusion of N6-phenylisopropyladenosine (1 mumol 1(-1)) into the medium reverted the adrenaline-induced inhibition seen during caloric restriction. The results suggest that local modulators such as adenosine are of primary importance for the apparent change of responsiveness to adrenaline and noradrenaline seen during starvation of human fat cells in vitro.

Adenosine↗
PubMed1985

Semiautomatic bioluminescence determination of glycerol using a computer controlled luminescence analyser (Berthold LB 950 T).

A semiautomatic determination of glycerol is described, in which luminescence produced by bacterial NADH-linked luciferase is measured by an automatic luminescence analyser (Berthold LB 950 T). The glycerol determination is based on the enzymatic conversion of glycerol to 3-phosphoglycerate, made irreversible by the presence of arsenate. NADH, formed in the glycerol-3-phosphate and glyceraldehyde-3-phosphate dehydrogenase reactions, is subsequently determined by the bacterial luciferase system. Stable kinetics of light emission were obtained by reducing the catalytic concentration of NAD(P)H: FMN oxidoreductase from 85 U/1 to 8.5 U/1. This method was applied to serum samples and validated by comparison with an enzymatic fluorimetric method. The new method is approximately 10 times more sensitive than the fluorimetric one. Moreover, it is simpler, more convenient, less time consuming and also less expensive than spectrophotometric, fluorimetric or radiochemical methods used for glycerol determination.

Computers↗
PubMed1985

A phase I trial of naloxone treatment in acute spinal cord injury.

Results of a Phase I trial of the opiate antagonist naloxone for treatment of patients with acute spinal cord injury are reported. Naloxone was administered in doses ranging from 5 to 200 mg/sq m (0.14 to 5.4 mg/kg) for up to 48 hours. The patients ranged in age from 16 to 79 years (mean 37 years). Twenty patients received naloxone as a loading dose of 5 to 50 mg/sq m (0.14 to 1.43 mg/kg), followed by a maintenance dose of 20% of the loading dose given as a continuous infusion hourly for 47 hours (Group 1). Nine patients received a loading dose of 100 to 200 mg/sq m (2.7 to 5.4 mg/kg) and a maintenance dose of 75% of the initial dose hourly for 23 hours (Group 2). These higher doses (2.7 to 5.4 mg/kg) have been found to be effective in experimental spinal cord injury. Neurological examinations were performed and somatosensory evoked potentials (SEP's) were obtained as soon after admission as possible and again 1, 2, 3, and 7 days, 3 weeks, and 6 weeks to 6 months after admission. The 20 Group 1 patients who received 1.43 mg/kg or less of naloxone showed no improvement in neurological status or SEP's. All but three (15%) of these patients had a complete neurological deficit at the time of admission. Treatment was begun an average of 12.9 hours after injury. Among the nine Group 2 patients treated with 2.7 mg/kg or more, there were five patients (56%) with incomplete deficits. This group received naloxone an average of 6.6 hours after admission. Two of the five Group 2 patients with incomplete lesions showed improvement in their neurological condition and/or SEP's within 36 hours of receiving the drug. One of the four Group 2 patients with a complete lesion at the time of admission was able to localize pressure sensation in his legs 36 hours after completion of the drug infusion. Four Group 2 patients (two with complete and two with incomplete lesions) have shown improvement in their SEP's, suggesting recovery of SEP's in a dose-related fashion. Four patients experienced increased pain after administration of the loading dose and during the maintenance infusion; in only one patient was this severe enough to require discontinuation of the drug. Of the 29 patients treated with naloxone, four died within 6 weeks of admission, for a mortality rate of 13.8%.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Homes for the aged and health resorts. Reflections on the quality of life in old age homes].

The quality of living in homes for the elderly and health resort institutions must be assessed in accordance with subjective and objective criteria. From the medical point of view, stress factors in the living area should be avoided, and health-promoting factors introduced. In this connection, consideration must be given to the biological, psychological and sociological aspects of ageing. Both in homes for the elderly and in health resort institutions, the particularly features of variability of interior design, compactness, clarity, safety, separation of functional rooms, furnishability and domestic comfort should be taken into account. The question of comfort (homeliness) in the health resort clinics, would appear to be an important factor, since it promotes patient contentment and willingness to cooperate, and thus also patient compliance.

Aged↗
PubMed1984

Human express saccades: extremely short reaction times of goal directed eye movements.

Human subjects were asked to execute a saccade from a central fixation point to a peripheral target at the time of its onset. When the fixation point is turned off some time (approximately equal to 200 ms) before target onset, such that there is a gap where subjects see nothing, the distribution of their saccadic reaction times is bimodal with one narrow peak around 100 ms (express saccades) and another peak around 150 ms (regular saccades) measured from the onset of the target. Express saccades have been described earlier for the monkey.

Adolescent↗
PubMed1984

Express-saccades of the monkey: reaction times versus intensity, size, duration, and eccentricity of their targets.

Monkeys were trained to fixate a small spot of light (fixation spot) and to saccade to a peripheral target if and only if the fixation spot was turned off. If the offset of the fixation spot preceded the onset of the peripheral target by a temporal gap of more than 140 ms the animals could change their direction of gaze after saccadic reaction times of no more than 70-80 ms (express-saccades). The reaction times of the express-saccades depend on the luminance and the size of the target and decrease from about 120 ms for near threshold targets by about 50 ms in a range of 2,5 log units above threshold (gap duration 200 ms). The minimum reaction time and the target size for which the minimum is reached are functions of the retinal eccentricity of the target. Comparison with response latencies of afferent visual neurons suggests that the dependence of the reaction times of express- as well as regular-saccades on the physical parameters of the target is mostly determined by retinal factors. The short reaction times of the express-saccades are discussed in relation to the reaction times of other visually-guided goal-directed movements.

Animals↗
PubMed1984

Express-saccades of the monkey: effect of daily training on probability of occurrence and reaction time.

Two monkeys learned to make saccadic eye movements from a central fixation point to a peripheral target, when there was a temporal gap between fixation point offset and target onset. Under these conditions the animals made saccades after extremely short reaction times (less than 100 ms), so called express-saccades. With ongoing training the rate of occurrence increased (10 to 1005) and the reaction time of the express-saccades decreased (95 to 75 ms). The training effects were mediated by the amount of previously executed express-saccades and they were also spatially selective for express-saccades to that target position that had been used during training. The training effects on the express-saccades can be saturated after less than 7 days of daily training and are reversible after another 7 days of no training. The results indicate the existence of a fast-operating visuo-to-oculomotor pathway which can be quickly and reversibly modified by daily exercise.

Animals↗
PubMed1984

[Rapid determination of agaritin in commercial mushrooms (Agaricus bisporus) with high performance liquid chromatography].

A procedure is described for the determination of agaritine in the commercial mushroom Agaricus bisporus by high performance liquid chromatography (HPLC). Agaritine was extracted from the mushroom sample with methanol and the filtered extract diluted with phosphate buffer. An aliquot of this solution was used directly for the HPLC-separation on a cation exchange column (Partisil SCX) with 0.5 mM phosphate buffer (pH 1.8) as mobile phase and u.v. monitoring at 237 nm. The agaritine content in fresh mushrooms was found to be in the range of 94-629 mg/kg fresh weight. Canned mushrooms contained 1-55 mg/kg drained weight with 3-103 mg/l in the liquid. The highest agaritine values were found in dried commercial mushrooms amounting to 2,110-6,905 mg/kg.

Basidiomycota↗
PubMed1984

Comparison of histamine release assay and RAST inhibition as tools for allergen extract standardization.

We compared allergen-induced histamine release (HRA) from actively sensitized human leukocytes and RAST inhibition (RI) for their capacity to measure the activity of allergen extracts. Four different grass pollen preparations were investigated for their allergenic activities by employing leukocytes and sera from 13 patients sensitive to grass pollen allergens. We could demonstrate that both test systems detect differences in allergenic activities of the preparations with similar accuracy and reproducibility. HRA is more sensitive than RI but shows greater variability of the results. Pooling of sera from individual patients diminishes individual sensitivities in RI. By this means the precision of RI is further increased. As reagents for RI can be standardized and stored under stable conditions, RI can be performed at different times and different laboratories under identical conditions. For these reasons, RI seems to be more suitable for routine standardization of allergen extracts than HRA.

Adolescent↗
PubMed1983

[Brain-jogging].

Explore the source record for details and available documents.

Exercise Therapy↗
PubMed1983

Saccadic eye movements after extremely short reaction times in the monkey.

Monkeys were trained to change their direction of gaze from one point (fixation point) to another (target). If the fixation point was extinguished at the same time when the new target occurred the saccadic reaction times (SRT) were in the order of 200 ms. If the fixation point disappeared 150-250 ms before the new target occurred (gap with no visible stimulus) monkeys made regular saccades after shorter reaction times of about 140 ms. In addition animals in the gap situation made saccades that had reaction times of no more than 70-80 ms measured from the onset of the new target (Express-Saccades). The reaction times of the E-saccades have standard deviations of only +/- 3 ms. E-saccades occurred with a frequency of up to 80% for gaps of 200-240 ms. If the gap was shorter than 180 ms increasingly more regular saccades were made with reaction times of 140-160 ms. With gap duration decreasing from 140 ms to zero all saccades were regular with SRTs increasing linearly to more than 200 ms. In one animal almost all E-saccades fell short and were corrected after less than 250 ms depending on the size of the error: large errors were corrected faster than small ones.

Animals↗
PubMed1983

Saccadic reaction times and activation of the prelunate cortex: parallel observations in trained rhesus monkeys.

Rhesus monkeys were trained to fixate a small spot and saccade to a second stimulus in the near periphery if the fixation spot went off. In different tests the target stimulus could occur at various delay times before or after the offset of the fixation spot. During periods of single unit recording from the prelunate cortex neural events were measured together with saccadic reaction times (SRT): If the stimulus was visible for a period of time (1 or 0.5 s) before the fixation spot disappeared (positive "delayed saccade" task) the SRT reached values of more than 300 ms. The SRTs were shorter when the target stimulus occurred simultaneously with the offset of the fixation spot ("saccade" task). SRT were shortest (approximately 150 ms) if the target stimulus appeared 100-250 ms after the offset of the fixation spot (negative "delayed saccade" task). Moreover, they decreased with the time of daily training. The different behavioural conditions resulted in different types of cortical activity with different latencies: In "saccade" and negative "delayed saccade" tasks the neurons on-responses could be enhanced in comparison to the passive visual on-responses during stationary fixation. The latencies of the on-response and the enhanced on-response were equal with approximately 80 ms. In striking contrast the latencies of the presaccadic activation (PSA) in the positive "delayed saccade" tasks were more than twice as long with about 200 ms. Daily training influences both the SRTs and the PSA: The SRTs become shorter by more than 150 ms in positive "delayed saccade" tasks (delay: 300-500 ms) and the percentage of PSA-neurons decrease from more than 70% to less than approximately 20% after 3 weeks of daily training and recording. The temporal aspects of events preceding visually guided eye movements are important to understand the serial and parallel processing in cortical and subcortical structures that are involved in the learning, initiation, and execution of goal directed movements.

Animals↗
PubMed1983

An accurate and linear infrared oculometer.

A method for measuring horizontal and vertical eye movements is described. The oculometer utilize infrared light and resolves 0.1 degree over a linear range of +/- 20 degrees. The simultaneous observation of the fixation target and eye position with an infrared mirror and two television cameras on a single monitor makes the mechanical and electrical calibration very easy. The system has been used successfully in animal studies of vision and eye movements, in particular during recording of single cells in visual brain structures of behaving monkeys.

Animals↗
PubMed1983

Compliance testing by measurement of piracetam in urine--a possible method of compliance control for piracetam intakers. An empirical investigation.

All teams of investigators concerned with compliance rate have come to the conclusion that one can seldom rely on patients to take their tablets as prescribed. In case of long-term medication the problem becomes even more acute. A method for checking on compliance is, therefore, of great help in controlling medical therapy as well as in judging the effectiveness of pharmaceuticals. The results of this study imply that diachronic determination of piracetam concentration in patients' urine is an especially simple way of testing compliance without undue strain on the patient.

Adult↗
PubMed1983

Effects on fertilization of rabbits of insemination with ejaculates treated with PG-dehydrogenase and antisera to PGE-2 and PGF-2 alpha.

PGE-2 and PGF-2 alpha in rabbit semen were selectively inactivated by incubation with antisera, or most of the seminal prostaglandins were transformed into biologically inactive 15-keto-prostaglandins by prostaglandin-15-hydroxydehydrogenase(PG-15-HDH). These treated ejaculates were vaginally inseminated. Compared to the controls (738 eggs of which 94% were fertilized) a dose-dependent reduction of the fertilization rate was observed with the anti-PGF-2 alpha-treated ejaculates. A non-uniformly, but statistically significantly reduced fertility was found in the other 2 treatment groups. After incubation with higher doses of PG-15-HDH, some fertilization was accomplished with ejaculates showing an extremely weak forward progression or immotile spermatozoa. An improvement in sperm motility, however, was observed in ejaculates treated with antiserum to PGF-2 alpha. Seminal prostaglandins may not exclusively affect sperm motility. The observed influences on the fertilization rate after treatment of spermatozoa with antisera to PGE-2 and PGF-2 alpha or PG-15-HDH suggest that these are local effects in the female genital tract.

Animals↗