Biomedical subjects

U Kischka

Publications and source records attributed to U Kischka.

27 records · Page 2Linked to original sources

PubMed1995

Circulating selectin- and immunoglobulin-type adhesion molecules in acute ischemic stroke.

BACKGROUND AND PURPOSE: Cellular adhesion molecules mediate adhesion between endothelial cells and leukocytes as a precondition for extravasation of leukocytes at sites of tissue injury. The pattern of release of circulating adhesion molecules has been characterized in patients with acute ischemic stroke. METHODS: Serum concentrations of soluble selectin-type adhesion molecules (solube endothelial leukocyte adhesion molecule-1 [sELAM-1], soluble lymph node homing receptor [sL-selectin]) and immunoglobulin-type adhesion molecules (soluble vascular cell adhesion molecule-1 [sVCAM-1], soluble intercellular adhesion molecule-1 [sICAM-1]) were serially determined (at hours 4, 8, and 10 and at days 1, 3, and 5) in 22 patients with acute ischemic stroke. As control subjects, age- and sex-matched individuals with (n = 40) and without (n = 22) vascular risk factors were studied. RESULTS: We observed increased concentrations of sICAM-1 and decreased levels of sL-selectin in patients with risk factors even in the absence of stroke. Patients with acute stroke had, in addition, an initial transient increase of sELAM-1 and a persistent increase of sVCAM-1. CONCLUSIONS: The results suggest a chronic alteration of expression of adhesion molecules sICAM-1 and sL-selectin in subjects with risk factors for atherosclerosis; they also indicate acute changes of levels of sELAM-1 and sVCAM-1 in response to acute ischemic stroke. Determination of soluble adhesion molecules could allow in vivo monitoring of the initial steps of leukocyte-mediated brain damage in acute ischemic stroke.

Aged↗

PubMed1993

Carbachol and naloxone synergistically elevate dopamine release in rat striatum: an in vivo microdialysis study.

Striatal dopamine (DA) release increased to 184% of baseline after 10-20 min of continuous intrastriatal perfusion with 10 mM carbachol, dropping to 124% after 30-40 min. The addition of 100 microM naloxone amplified (to 236% of baseline) and prolonged the increase in DA release, but naloxone alone (up to 1 mM) had no effect. These data suggest that activation of opiate-releasing striatal neurons suppresses cholinergic stimulation of DA release.

Animals↗

PubMed1993

Potentiation by choline of basal and electrically evoked acetylcholine release, as studied using a novel device which both stimulates and perfuses rat corpus striatum.

We examined the release of acetylcholine (ACh) and dopamine (DA) using a novel probe through which striatal neurons could be both superfused and stimulated electrically in both anesthetized and freely moving awake animals. Optimal stimulation parameters for eliciting ACh release from cholinergic neurons differed from those required for eliciting DA release from dopaminergic terminals: at 0.6 ms pulse duration, 20 Hz and 200 microA, ACh release increased to 357 +/- 30% (P < 0.01) of baseline and was blocked by the addition of tetrodotoxin (TTX). Pulse durations of 2.0 ms or greater were required to increase DA release. Unlike ACh release, DA release showed no frequency dependence above 5 Hz. The maximal evoked releases of ACh and DA were 556 +/- 94% (P < 0.01) and 254 +/- 38% (P < 0.05) of baseline, respectively. Peripheral administration of choline (Ch) chloride (30-120 mg/kg) to anesthetized animals caused dose-related (r = 0.994, P < 0.01) increases in ACh release; basal release rose from 117 +/- 7% to 141 +/- 5% of initial baseline levels (P < 0.05) and electrically evoked ACh release rose from 386 +/- 38% to 600 +/- 34% (P < 0.01) in rats given 120 mg/kg. However, Ch failed to affect basal or evoked DA release although neostigmine (10 microM) significantly elevated basal DA release (from 36.7 fmol/10 min to 71.5 fmol/10 min; P < 0.05). In awake animals, Ch (120 mg/kg) also elevated both basal (from 106 +/- 7% to 154 +/- 17%; P < 0.05) and electrically evoked (from 146 +/- 13 to 262 +/- 16%; P < 0.01) ACh release.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1993

Facilitation of motor evoked potentials from magnetic brain stimulation in man: a comparative study of different target muscles.

The influence of tonic muscle contraction and stimulus intensity on compound muscle action potentials (CMAPs) elicited by magnetic brain stimulation was studied in the biceps brachii (34 subjects), the abductor digiti minimi (11 subjects), the anterior tibial muscle (12 subjects), and the soleus muscle (5 subjects). The muscles were examined at rest and with various degrees of background contraction of up to 60% of maximum force. Stimulus intensity was set at threshold (TSI) or 20% above threshold (1.2 TSI), and in one series additionally at 50% above threshold (1.5 TSI). The effect of voluntary background contraction on CMAP onset latency was similar in the four muscles tested: the latencies shortened by approximately 3 ms when the muscle changed from the relaxed to the contracted state of the 10% of maximum force. An additional increase in the background contraction up to 60% of maximum force induced only few, if any, additional decreases in latency. The uniformity of the latency shift in distal and proximal muscles conflicts with the idea of recruitment of larger and rapidly conducting motoneurons being the cause, since this hypothesis would imply a more pronounced latency reduction in distal than in proximal muscles. The shorter latency during voluntary contraction is more likely due to an enhanced synaptic efficacy at spinal level. Since the motoneurons are brought into an increased state of activity during contraction, they require less temporal summation to reach firing threshold and thus discharge earlier. The CMAP amplitudes of the different muscles were more distinctly affected by voluntary background contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Electrophysiologic detection of extrapyramidal motor signs in Alzheimer's disease.

We applied quantitative methods to measure extrapyramidal signs in 50 Alzheimer's disease (AD) patients and 40 age-matched control subjects. We measured tremor using accelerometers, bradykinesia using computer-detected reaction times (RTs) and movement times (MTs), and rigidity using a strain gauge linked to a movable arm rest. We excluded subjects with a clinical diagnosis of Parkinson's disease and subjects who required antiparkinsonian, neuroleptic, or anxiolytic medications. Aside from rigidity in two patients, there were no extrapyramidal signs on clinical examination. Based on electrophysiologic measures, however, there was a significant increase in muscle tone (p < 0.001), RT (p < 0.01), and MT (p < 0.03) in AD patients as a group compared with control subjects. Within the AD group, muscle tone and MTs increased across clinical stages of dementia severity (p < 0.05). Tremor frequency and amplitude were normal in AD subjects. These data indicate that quantitative neurophysiologic measures are superior to conventional clinical examinations in detecting extrapyramidal signs in AD. The pathologic substrates of extrapyramidal signs in AD are uncertain but seem to be linked to the degenerative AD process.

Aged↗

PubMed1992

Cerebral symptoms after whiplash injury of the neck: a prospective clinical and neuropsychological study of whiplash injury.

Twenty one unselected patients with an acute whiplash injury of the neck had neurological and neuropsychological assessment, cervical x rays, EEG, BAEP, MRI, and an otoneurological examination within two weeks of the injury. Subjectively, 13 patients reported concentration deficits, 18 reported sleep disturbances, 9 had symptoms of depression, and 7 female patients told of menstrual irregularities. Neuropsychological examination revealed significantly lower performance in tests related to attention and concentration compared to sex, age and educational matched control subjects. Otoneurological examination showed abnormalities in 9 of 17 whiplash subjects. EEG showed questionable changes in 8 of 18 recordings. MRI and BAEP were normal in all patients. Repeat neuropsychological testing in 15 patients at three months showed that attention deficits had improved but were still shown in 12 of 14 and the concentration deficits in 8 of 13 patients. At one year all patients had returned to work, 16 to full and 5 to part time employment. In 4, cognitive dysfunction remained the only significant problem. These findings are discussed as being compatible with possible damage to basal frontal and upper brain stem structures after whiplash injury of the neck.

Adolescent↗

PubMed1991

Cerebral symptoms following whiplash injury.

Fifty-two patients suffering from various chronic disturbances after whiplash injury were studied retrospectively. Frequencies and coincidences of the complaints and symptoms were calculated. From those 26 patients who had reported cognitive disturbances 18 were examined with an extensive neuropsychological test battery. The results showed deficits mainly in the attention and concentration tests, to a lesser extent in the memory tests and least in the tests of higher cognitive functions. The findings were discussed as being compatible with damage to frontobasal cerebral structures and the upper brainstem as a consequence of the whiplash injury.

Adult↗

PubMed1989

[Cognitive and psychological disorders following whiplash injury: 2 case reports concerning the controversy between the organic versus the psychogenic etiology of symptoms].

A couple who had experienced a whiplash-injury of the neck in the same accident, underwent neurological and neuropsychological examination two years after the trauma. The subjective complaints were very similar: head- and neck pain, vertigo, adynamia, sleep disturbances and severe disturbances of attention, concentration and memory. The neuropsychological examination of the husband demonstrated distinct deficits of attention, concentration and memory. The wife, however, showed positive signs of a neurotic-conversion behaviour. These case reports illustrate both sides of the controversy on the organic versus psychogenic etiology of the cerebral symptoms following whiplash-injury of the neck.

Adult↗

PubMed1989

Computed tomography, electroencephalography, and clinical features in the differential diagnosis of senile dementia. A prospective clinicopathologic study.

The accuracy of computed tomography, electroencephalography, and clinical features in the differential diagnosis of senile dementia was studied prospectively. Out of 50 demented patients, autopsy revealed 32 cases with either senile dementia of the Alzheimer's type (SDAT), multi-infarct dementia (MID), or a combination of both. Eighteen patients had dementia caused by other diseases. Based on a combination of computed tomography, electroencephalography, and clinical features, senile dementia of the Alzheimer's type was differentiated from all 50 patients, with a specificity of 83% and a sensitivity of 80%. Focusing on senile dementia of the Alzheimer's type, multi-infarct dementia, or a combination of both, specificity decreased to 65% and sensitivity to 47%. Comparing the different methods, multi-infarct processes were diagnosed with a higher sensitivity by the clinical features (73%) than by computed tomography (18%) or electroencephalography (18%). None of the methods validly differentiated multi-infarct dementia from a combination of multi-infarct dementia and senile dementia of the Alzheimer's type.

Aged↗