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Biomedical subjects

K Reiners

Publications and source records attributed to K Reiners.

At least 55 records · Page 3Linked to original sources

Degeneration of substantia nigra in chronic Parkinson's disease visualized by transcranial color-coded real-time sonography.

To detect morphologic abnormalities in Parkinson's disease (PD), we examined 30 patients with PD and 30 age- and sex-matched nonparkinsonian controls by transcranial color-coded real-time sonography (TCCS). In 12 severely affected PD patients, the echogenicity of the substantia nigra was distinctly increased. In the remaining 18 PD patients and in all controls, the substantia nigra was poorly visualized or nondetectable by TCCS. The degree of hyperechogenicity of the substantia nigra closely correlated with the severity and duration of PD (p < 0.001). The increased echogenicity of the substantia nigra notably results from nigral gliosis and reflects the stage of degeneration.

Aged

Multiple symmetric lipomatosis: abnormalities in complex IV and multiple deletions in mitochondrial DNA.

Multiple symmetric lipomatosis (MSL) is a rare disorder of middle life characterized by large nonencapsulated lipomas distributed around the neck, shoulders, and other axial regions. Neurologic involvement, particularly peripheral neuropathy, is frequent. The pathogenesis of the syndrome is still unknown, but ragged-red fibers are occasionally present in muscle of affected patients, suggesting a mitochondrial abnormality. We studied 11 unrelated patients with MSL by means of neurophysiology, muscle morphology, muscle biochemistry, Southern blot, and PCR analysis of mitochondrial DNA. All patients were men aged 41 to 63 years. Clinical or electrophysiologic signs of a sensorimotor polyneuropathy were present in nine patients, eight of whom had a history of alcoholism. In muscle biopsy specimens, the most prominent feature was pathologic subsarcolemmal aggregates of mitochondria. Biochemical analysis of respiratory chain enzymes revealed a moderate but significant decrease of cytochrome c oxidase activity as compared with age-matched controls. In one patient, Southern blot analysis showed multiple deletions of mitochondrial DNA. We conclude that mitochondrial dysfunction is common in MSL and may be based on identifiable defects in the mitochondrial genome.

Adult

Serum levels of soluble E-selectin (ELAM-1) in immune-mediated neuropathies.

Adhesion molecules are critically involved in inflammatory responses. We studied serum concentrations of the soluble form of E-selectin (endothelial-leukocyte adhesion molecule-1, ELAM-1) in 187 patients with neuropathies of diverse etiology, 54 patients with other noninflammatory, nondemyelinating neurologic disorders, and 15 healthy controls. Serum E-selectin levels, quantitated by a two-site enzyme-linked immunosorbent assay, were significantly increased in 126 patients with Guillain-Barré syndrome (GBS) (mean +/- SD, 45.1 +/- 16.3 ng/ml) and 13 patients with vasculitic neuropathies (47.1 +/- 19.1ng/ml) compared with patients with other neurologic diseases (19.8 +/- 7.4 ng/ml) and healthy controls (21.9 +/- 8.1 ng/ml). In GBS, E-selectin levels were temporally related to disease activity. Cytokine-mediated upregulation of E-selectin may be important in homing and attachment of leukocytes to endoneurial endothelial cells. Raised E-selectin concentrations probably reflect endothelial cell activation occurring early in the sequence of immunopathologic events culminating in peripheral nerve damage.

Cell Adhesion Molecules

High frequency bursting during rapid finger movements in an unusual case of epilepsia partialis continua.

Myoclonic activity was analyzed in a 25-year-old male patient suffering from epilepsia partialis continua in his right finger and hand extensors and flexors. The involuntary tremorlike regular muscle jerks occurred at an average rate 7.7/s under resting conditions. Bursting frequency did not change during smooth ramp movements but increased up to 25/s during rapid extensions of the fingers. The EEG showed trains of sharp waves over the left temporoparietal and the midcentral regions but backaveraging did not yield reproducible jerk-related potentials. Somatosensory evoked potentials were not enhanced. It is suggested that the observed pattern of muscle jerks resulted from a spontaneous bursting behaviour of motor cortical neurones.

Adult

Soluble ICAM-1 serum levels in multiple sclerosis and viral encephalitis.

Intercellular adhesion molecule ICAM-1 has a crucial role in the induction of an immune response and is instrumental in migration of T cells into inflamed tissue. We studied soluble ICAM-1 concentrations in patients with multiple sclerosis (MS), viral encephalitis, and other immunologic diseases, and compared results with those in other noninflammatory, nondemyelinating neurologic disorders as well as in healthy controls. MS patients with clinically active disease or enhancing lesions on MRI had elevated serum levels of soluble ICAM-1. Concentrations of soluble ICAM-1 were also increased in some patients with viral encephalitis. These findings raise the possibility that circulating ICAM-1 serves as a marker of acute inflammatory events in the brain and add to evidence implicating this adhesion molecule in the pathogenesis of MS.

Cell Adhesion Molecules

Response of vasoactive substances to reduction of blood volume during hemodialysis in hypotensive patients.

Hypotension is a frequent complication in patients subjected to regular hemodialysis. Insufficient regulation of blood pressure following dialysis with ultrafiltration has been attributed to a lack in hormone activation. To determine whether altered production of vasoactive hormones is involved in the breakdown of blood pressure regulation during hemodialysis (HD), blood volume (BV), atrial natriuretic peptide (ANP), plasma renin activity (PRA), aldosterone (Aldo), norepinephrine (NE), epinephrine (Epi), intact immunoreactive parathyroid hormone (iPTH) and arginine vasopressin (AVP) were examined. The relative BV was measured by continuous hemoglobinometry during the HD period of about 240 min. The total decrease in BV at the end of treatment was 23.5 +/- 4.8% of the pretreatment value. Systolic blood pressure (SBP) was 99.6 +/- 23.0 mmHg before dialysis compared with 74.6 +/- 18.8 mmHg at the end of dialysis and heart rate (HR) increased from 76.3 +/- 5.5/min before to 92.0 +/- 10.0/min at the end of dialysis. Despite the wide range of interindividual variance, the hormonal changes indicate that hypotensive patients under HD develop reduced sensitivity of the angiotensin-renin, adrenergic and AVP systems to volumetric stimuli. A paradoxical activation in iPTH and PRA independent Aldo secretions is apparent.

Aldosterone

Reversible conduction block in human ischemic neuropathy after ergotamine abuse.

Conduction block [a significant reduction in compound muscle action potential (CMAP) amplitude after proximal compared to distal stimulation] is often found in demyelinating neuropathies, including inflammatory neuropathies and degenerative neuropathies, such as "liability to pressure neuropathy." There is experimental evidence that a transient conduction block can occur in rats after ischemic lesions of peripheral nerves are induced either by ligation of arterial vessels supplying nerve trunks, or by injection of arachidonic acid into peripheral arterial vessels. Conduction block has also recently been described in cases with necrotizing vasculitis. To date, however, no example of a reversible conduction block has been reported in human ischemic neuropathy.

Adult

Oscillatory activity in different motor subsystems in palatal myoclonus. A case report.

In a patient with palatal myoclonus the mutual interaction between voluntary movements and the myoclonic activity was analysed. Amplitude and frequency of myoclonic activity in hand muscles were modulated by flexions and extensions. A 1:1 relationship was found between EMG-bursts in hand muscles and palatal movements. A 1:2 relationship was found between eye and finger movements. Resetting of myoclonus in the abductor digiti minimi muscle occurred after cutaneous ulnar nerve stimulation. It is suggested that feedback plays an important role in the generation of the oscillatory activity in PM in addition to pacemaker activity in brainstem neurons.

Aged

Neurological risk profile in organic erectile impotence.

Thirty men who presented with erectile impotence to the urological department underwent a thorough urological, angiological, and neurological examination with complementary neurophysiological tests of somatosensory and sympathetic and parasympathetic function. Most had vascular and neurological abnormalities. Clinical findings and electrophysiological tests for autonomic dysfunction had the highest yield of abnormal results. Nerve conduction studies and pudendal nerve somatosensory evoked potentials were far less informative. The lack of correlation between vascular and general neurological abnormalities emphasises that patients must be screened for both vascular and neurological dysfunction to prevent unrewarding vascular operation in impotent men.

Adult

Serum interleukin-2 concentrations in Guillain-Barré syndrome and chronic idiopathic demyelinating polyradiculoneuropathy: comparison with other neurological diseases of presumed immunopathogenesis.

Serum concentrations of the cytokine interleukin-2 (IL-2) were quantitated by enzyme-linked immunosorbent assay in 42 patients with Guillain-Barré syndrome, 15 patients with chronic idiopathic demyelinating polyradiculoneuropathy, 37 patients with other neuropathies, 54 patients with other noninflammatory, nondemyelinating neurological disorders, and 26 healthy control subjects. We found markedly increased serum levels of IL-2 in patients with Guillain-Barré syndrome and to a much lesser extent, in patients with chronic idiopathic demyelinating polyradiculoneuropathy. Increased serum concentrations of IL-2 in patients with Guillain-Barré syndrome returned to normal in parallel with recovery from the disease. These findings suggest ongoing T-cell proliferation in patients with Guillain-Barré syndrome and some patients with chronic idiopathic demyelinating polyradiculoneuropathy. IL-2 levels were also raised in patients with active multiple sclerosis, myasthenia gravis, and herpes simplex encephalitis, and some patients with polymyositis, invoking T cells in the pathogenesis of these diseases.

Autoimmune Diseases

Does tremor pace repetitive voluntary motor behavior in Parkinson's disease?

In patients with Parkinson's disease and in normal subjects, the influence of tremor on repetitive voluntary movement was investigated in the index finger by comparing frequency of isometric force tremor with frequency of voluntary alternating isometric contractions. Tremor frequency, measured over the range from 0 to 70% maximum voluntary force, usually increased with force. The tremor frequency band was lower and more often overlapped with the upper voluntary frequency range in patients than in normal subjects. Normal subjects could accurately produce voluntary contractions at all cue frequencies from 1 to 5 Hz. Patients could produce auditory-paced frequencies of 1 and 2 Hz, but at higher cue frequencies, their voluntary contractions were often faster or slower than the cue. The faster or "hastened" voluntary frequencies were within the tremor frequency band, whereas the slowed voluntary frequencies were below it. Maximal voluntary frequency was often greater than the lowest but always less than the highest tremor frequency. It is concluded that parkinsonian tremor may pace voluntary repetitive movements to go faster than intended with the highest tremor frequency being an upper limit for voluntary frequency. Similar mechanisms may underlie the hastened repetitive vocal responses that were also observed in the parkinsonian patients.

Adult

Ultrastructural abnormalities of mitochondria and deficiency of myocardial cytochrome c oxidase in a patient with ventricular tachycardia.

A 30-year-old woman presented with life-threatening ventricular tachycardia without overt heart disease. Ultrastructural investigation of endomyocardial biopsy disclosed abnormally structured and often enlarged mitochondria. Morphometry revealed the ratio of volume density of mitochondria to myofibrils to be markedly increased to 0.667 as compared with five controls (mean: 0.46; range: 0.445-0.479). Investigation of mitochondrial respiratory chain enzymes revealed a 90% reduction in activity of cytochrome c oxidase. Our data suggest that mitochondrial cardiomyopathy may induce malignant ventricular arrhythmias.

Adult

Acute posterior multifocal placoid pigment epitheliopathy with cerebral involvement.

In a patient with angiographically proven cerebral vasculitis five months after acute posterior multifocal placoid pigment epitheliopathy (APMPPE) neurological symptoms promptly responded to steroid treatment. Cerebrospinal fluid (CSF) showed a lymphocytic pleocytosis. Magnetic resonance imaging (MRI) revealed multifocal white matter lesions in the hemispheres and the brain stem suggesting a diffuse subcortical vasculitis.

Cerebral Arterial Diseases

Encephalo-myelo-radiculo-ganglionitis presenting as pandysautonomia.

A 68-year-old man developed pandysautonomia with severe orthostatic dysfunction, fixed heart rate, low serum levels of norepinephrine and epinephrine, absent sympathetic skin responses, and pupillary abnormalities. CSF protein was 92 mg/dl. In spite of a good recovery following corticosteroid administration, a relapse occurred, with accompanying sensory symptoms confined to both arms. Fatal sudden cardiac arrest occurred after 4 months. Autopsy revealed numerous lymphocytic infiltrates, predominantly in autonomic and sensory ganglia and, to a lesser extent, in the nerve roots, spinal cord, and brainstem without evidence for an underlying tumor. This case provides histopathologic evidence for an inflammatory etiology of panautonomic neuropathy in some patients.

Aged

Neurophysiology of fastest voluntary muscle contraction in hereditary neuropathy.

In patients with hereditary motor and sensory neuropathy types I (demyelinative) and II (neuronal) and in normal subjects, isometric force and electromyographic activity of the first dorsal interosseous muscle were recorded during fastest voluntary contractions and during twitches evoked by nerve stimulation. The maximum voluntary force of the first dorsal interosseous muscle was also measured. In patients, fastest voluntary contraction time (i.e., time from onset of contraction to peak force) was prolonged and inversely proportional to maximum voluntary force. Maximum rate of rise of tension (i.e., slope of rise in force) was reduced and directly proportional to maximum voluntary force. In patients with hereditary motor and sensory neuropathy type I, contraction time was longer and the maximum rate of rise of tension was lower than in those with hereditary motor and sensory neuropathy type II. In patients and normal subjects, voluntary contraction time was closely correlated with the duration of electromyographic bursts. In patients, the twitch contraction time was prolonged and inversely proportional to maximum voluntary force. Twitch contraction amplitude was diminished and directly proportional to maximum voluntary force. Neither twitch contraction time nor amplitude were dependent on the type of hereditary motor and sensory neuropathy. Twitch contraction time evoked by proximal nerve stimulation was minimally longer than that evoked by distal stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult