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Biomedical subjects

B Fischer

Publications and source records attributed to B Fischer.

At least 343 records · Page 19Linked to original sources
PubMed1983

Drug compliance of pregeriatric rehabilitation patients. Brief communication on a longitudinal investigation.

An overview on an follow-up study is given that concerns the drug-compliance of 990 pregeriatric rehabilitation patients. During 20 days the drug intake of every patient was controlled by riboflavine method. The compliance-rate was at 47.9 +/- 32.4%, and it was relatively constant during the course of the investigation. Other features as age, nationality, number of risk factors etc. correlated but moderately though significantly with the compliance-rate. The lowest values had foreigners, and/or patients prone to nicotine or alcohol abuse. The highest rate was found on patients being in the state after heart infarction.

Humans↗
PubMed1983

Intravenous injection of mice with bacteroides fragilis and Escherichia coli: role of Thioglycollate medium in the infectious process.

Mice were intravenously infected with E. coli, B. fragilis, and combinations of both, and the bacterial contents of livers, kidneys, and spleens were monitored from the first up to the 9th day postinfection. If Thioglycollate medium was added to otherwise sublethal doses of E. coli, the inoculum was able to induce severe and for some animals lethal infections. B. fragilis was not capable to produce prolonged infections; however, when given together with E. coli and Thioglycollate medium, both bacteria were recovered from some animal organs even on day 9 postinfection. Employing this experimental model of a mixed anaerobic/facultative bacterial infection, previous reports attributing animal lethality to E. coli were confirmed, but a synergism between E. coli and B. fragilis could not be demonstrated.

Animals↗
PubMed1982

Modifications of presaccadic activation on neurons in the extrastriate cortex during prolonged training of rhesus monkeys in a visuo-oculomotor task.

As a monkey learns to make a saccadic eye movement to a constantly illuminated peripheral stimulus the majority of cells in visual association cortex at the prelunate gyrus are activated before the eye movement (presaccadic activation, PSA). We recorded eye movements and this PSA extracellularly from single cells of behaving monkeys by microelectrode penetrations made during consecutive days of training. The PSA gradually disappears as training continues for some weeks. At the same time the animal's performance improves and saccadic reaction times decrease. The visuo-oculomotor task seems to be automated and its execution no longer needs a strong activation of the visual association cortex.

Animals↗
PubMed1982

Stimulatory (insulin-mimetic) and inhibitory (ouabain-like) action of vanadate on potassium uptake and cellular sodium and potassium in heart cells in culture.

(1) The influence of vanadate (Na3VO4) on sodium and potassium uptake as well as on cellular ion contents of sodium and potassium has been studied in heart muscle and non-muscle cells obtained from various species. An ouabain-like inhibition of potassium uptake (up to 50%), combined with a decrease of cellular potassium (up to 20%) has been observed by vanadate (10(-4)-10(-3) M) in heart non-muscle cells obtained from neonatal guinea pigs and chick embryos. In heart muscle and non-muscle cells prepared from neonatal rats, as well as in Girardi human heart cells, a vanadate-induced stimulation of potassium uptake (up to 100%), combined with a rise in cellular potassium (up to 20%) and without significant alteration of cellular sodium, has been found. A slight increase of 22Na+ influx can be measured in rat heart muscle cells and in Girardi human heart cells in the presence of vanadate (10(-4)--10(-3) M). (2) In beating rat heart muscle cells in culture, detrimental effects of serum deprivation--concerning beating properties, potassium uptake and cellular potassium--can at least in part be overcome by addition of vanadate. Furthermore, this compound prevents ouabain-induced signs of toxicity (contractures) in these cells. (3) The stimulatory effects of vanadate on potassium can be mimicked by insulin (1-10 mU/ml). Furthermore, vanadate produces an insulin-like stimulation of 2-deoxy-D-glucose uptake in rat heart muscle and non-muscle cells as well as in Girardi human heart cells. (4) The experimental data demonstrate an ouabain-like inhibition as well as an insulin-mimetic stimulation of potassium-uptake in various heart cells. The reason for this antagonistic mode of action may be due to the different capabilities of the heart cell types to reduce vanadium in the V-valence state of vanadium in the IV-valence state, thereby favouring either ouabain-like inhibition (vanadium V) or insulin-mimetic stimulation (vanadium IV) of potassium transport.

Animals↗
PubMed1982

Centrifugal elutriation studies in mast cells from rats, guinea pigs and man.

Elutriation is a cell separation method based on countercurrent centrifugation. For mast cell purification it is superior to density gradient methods since no foreign protein or dense material has to be removed from the purified cells. The elutriation profiles of peritoneal rat mast cells differ considerably if the cells come from non-sensitized or actively sensitized donor animals and/or from different strains. This result is another indication of an altered morphological state of mast cells due to active immunization and is dependent on genetic factors. Cell aggregation proved to be the main obstacle to elutriation purification of guinea pig tissue mast cells. Human mast cells from adenoid tissues, however, could be brought to 70-90% purity, even if the elutriation profiles varied from donor to donor.

Adenoids↗
PubMed1981

Enhanced activation of neurons in prelunate cortex before visually guided saccades of trained rhesus monkeys.

Single unit recording from trained rhesus monkeys demonstrate that the activity of the prelunate cortex is enhanced when a visual stimulus becomes a target of saccadic eye movement. As a rule, the enhancement is spatially selective: it does not occur if the animal makes an eye movement away from, rather than towards the stimulus. The results show that the prelunate cortex has access to an extra-retinal signal which is activated in association with events preceding visually guided eye movements. Whether the signal reflects the initiation of eye movement of the animal's interest in the stimulus, which he usually selects to initiate an eye movement, remains uncertain.

Animals↗
PubMed1981

Stimulus versus eye movements: comparison of neural activity in the striate and prelunate visual cortex (A17 and A19) of trained rhesus monkey.

Visual responses were recorded from single cells in the parafoveal striate (A17) and prelunate (A19) cortex of awake rhesus monkeys while they were fixating a stationary or moving spot of light in the presence of a moving or stationary stimulus. Retinotopy and stimulus requirements were found to be less strict in A19 as compared to A17. Striate cells preferred slow stimulus movements and displayed a large amount of binocular interaction. Many prelunate cells responded well to fast stimulus movements, all were binocular but only a few showed binocular interaction. In both areas an overall deficit of visual responses during saccadic eye movements was observed which was mostly due to the cells' inability to respond to stimuli moving at saccadic velocities. Only in A19 were there cells which seemed to receive non-sensory signals reducing visual responses during rapid eye movements. We concluded that the prelunate cortex has access to input which does not use the geniculate-striate pathway. The additional observation of presaccadic activation of some cells supports the idea that activity in the prelunate cortex may be associated with events related to visually guided changes of the direction of gaze and/or attention.

Animals↗
PubMed1981

Selection of visual targets activates prelunate cortical cells in trained rhesus monkey.

Cells in monkey prelunate association cortex display an enhanced visual activity after the onset of a stimulus in the receptive field, when the stimulus is simultaneously selected as a target for a saccadic eye movement. In the present study we observed a separate activation which is independent of the passive visual on-response and occurs in a given cell when the animal saccades to a steady stimulus in its receptive field. The activation begins when the stimulus is selected for foveation before the eye actually moves, but is not necessarily predictive for an eye movement.

Animals↗
PubMed1981

Long-term neuroleptic treatment of chronic schizophrenic patients: clinical and biochemical effects of withdrawal.

In 17 chronic schizophrenic patients under chronic neuroleptic treatment for 13 years, a 30-day drug withdrawal resulted in early relapse of four patients, slight deterioration in five, and slight amelioration in eight patients. No incidence of neuroleptic symptoms such as tardive dyskinesia occurred. Prolactin in plasma and cerebrospinal fluid (CSF), not being elevated under chronic treatment, decreased significantly after 30 days of withdrawal. Homovanillic acid and 3-methoxy-4-hydroxyphenylglycol in CSF ranged normally and did not change during withdrawal. In contrast, plasma noradrenaline was elevated and decreased after drug discontinuation. No unequivocal relationship between biochemical and psychopathological features was found.

Adult↗
PubMed1981

Histamine release from isolated mast cells as a bioassay system for the standardization of allergens.

Standardization of allergen extracts is still a problems not yet satisfactorily resolved. Allergic sensitization involves not only the production of allergen-specific antibodies of a certain class (IgE) but also changes in the morphological and functional state of the mast cells that bind and carry IgE and react with the allergen. We therefore designed a bioassay which covers the total allergenicity and also antibody-independent allergen effects. It is based on the release of histamine from isolated mast cells of actively sensitized guinea pigs: outbred animals receive one s.c. injection of the allergen extract to be tested and human serum albumin (HSA) as reference (standard) allergen. Three weeks later the mesenteric mast cells of these animals are isolated and challenged in vitro with varying concentrations of the test allergen and HSA. The relationship of the histamine release caused by the reference allergen HSA to that caused by the test allergen (e.g. rye or grass pollen, alternaria, and even house dust) can be used to estimate the sensitizing and challenging potency of the test allergen. For example, 2 different batches of rye pollen gave different results although the values obtained by identical batches were almost identical within 9 months. In addition, irritating impurities of the allergen extract might be recognized.

Allergens↗
PubMed1981

Fertilization following mixed insemination with 'cervix-selected' and 'unselected' spermatozoa in the rabbit.

The possible selection of spermatozoa for fertilization by the female genital tract was investigated using genetically homogeneous, numerically adjusted 'cervix-selected' and 'unselected' rabbit spermatozoa. Samples of spermatozoa were marked by 15 min exposure to 1.3 mg TEPA/ml and then washed for 15 min. TEPA-treated and control samples were inseminated alternately into the vagina (= 'cervix-selected') or uterine horns (= 'unselected') of prospective donors. After 6 h spermatozoa were recovered from the uterine horns of the donors. Equal numbers of 'selected' and 'unselected' spermatozoa were inseminated either into the uterine horns (24 does) or oviducts (25 does) of recipients. The fertilization rates were 48 and 72%, respectively. Significantly more eggs were fertilized by untreated than by TEPA-treated spermatozoa. Almost identical fertilization rates, however, were observed between 'cervix-selected' and 'unselected' spermatozoa. It is concluded, therefore, that in the rabbit no selection of (preincubated) spermatozoa for fertilization takes place at the cervical level.

Animals↗
PubMed1981

[Conception of the Klausenbach-Clinic for pre-geriatrics: Diagnostic, therapeutic and scientific aspects (author's transl)].

Risk-groups, cerebrovascular insufficiency without neurologic symptoms, transient ischemic attacks of the A. Carotis and/or A. Vertebralis, state after cerebral infarction. There are multidisciplinary possibilities for the consideration (internistic examination, neurologic-psychiatric examination with REM-phases patterns, permanent EEGs, power-spectrums, ultrasonic examinations, examination of the metabolism of the brain, psychologic examination with psychometric and psychopathometric procedures). There are various therapeutic employments, too (medical, psychologic-psychiatric therapy with brain-function-training, work-therapy (hobbies), and recreational activities, dietetic and physical therapy, health-talks, pension and social debates). By example of the health-talks there is shown what we mean with patient-adapted information. The scientific examinations concern retrospective studies of the anamnesis and psychometric investigations. Finally the patient-compliance is discussed.

Aged↗
PubMed1981

Inhibition by azelastine of the immunologically induced histamine release from isolated guinea pig mast cells.

4-(p-Chlorobenzyl)-2-(hexahydro-1-methyl-1H-azepin-4-yl)-1-(2H)-phthalazinone (azelastine, A 5610) did not affect the spontaneous histamine release but inhibited effectively the allergic histamine release from isolated mesenteric mast cells of actively sensitized guinea pigs. At 10(-6) mol/l concentration the inhibition was almost equal to that caused by adrenaline (10(-8) mol/l).

Animals↗