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Biomedical subjects

J A Schmitt

Publications and source records attributed to J A Schmitt.

At least 19 recordsLinked to original sources
PubMed2001

Non-serotonergic pharmacological profiles and associated cognitive effects of serotonin reuptake inhibitors.

The current study was carried out to investigate the cognitive effects of two serotonin reuptake inhibitors (SSRIs), sertraline and paroxetine, with special reference to differences in their affinity for other neurotransmitter systems, i.e. anticholinergic activity of paroxetine and putative dopamine reuptake activity of sertraline. The study was conducted according to a double-blind, three-way cross-over design. During three treatment periods of 2 weeks, 24 healthy middle-aged (aged 30-50 years) subjects of both sexes received sertraline (50 mg on days 1-7, 100 mg on days 8-14), paroxetine (20 mg on days 1-7, 40 mg on days 8-14) and placebo. Paroxetine specifically impaired delayed recall in a word learning test at a dose of 20 and 40 mg. Sertraline did not affect word learning but improved performance on a verbal fluency task at a dose of 50 and 100 mg. Neither drug affected performance on a short-term memory scanning task. These subtle but significant changes in cognitive performance can be explained by subtle differences in pharmacological profiles of these SSRIs. The additional anticholinergic effects of paroxetine could account for its induction of long-term memory impairment. Similarly, the additional dopaminergic effects of sertraline could account for its induction of slightly improved verbal fluency. The impairing and facilitating cognitive effects of paroxetine and sertraline, respectively, may be more pronounced in the elderly depressed patient.

Adult↗
PubMed2000

Tryptophan depletion impairs memory consolidation but improves focussed attention in healthy young volunteers.

Animal and human studies have provided evidence for serotonergic modulation of cognitive processes. However, the exact nature of this relationship is not clear. We used the acute tryptophan depletion (ATD) method to investigate the effects of lowered serotonin synthesis on cognitive functions in 17 healthy young volunteers. The study was conducted according to a placebo-controlled, double-blind, crossover design. Cognitive performance and mood were assessed at baseline and 5 and 9 h after administration of ATD. A specific impairment of word recognition, without effects on short-term memory, occurred during ATD. No memory deficits were seen if ATD was induced after acquisition of new words. The Stroop Test and dichotic listening task demonstrated a modality independent improvement of focussed attention after ATD. Fluency was also improved after ATD. ATD did not alter speed of information processing, divided attention or planning functions. These results indicate that serotonin is essential in the process of long-term memory consolidation, primarily in the first 30 min after acquisition. Improvement of specific cognitive processes by lowered 5-HT function may be linked to the removal of inhibitory actions of 5-HT in the cortex.

Adult↗
PubMed1993

[Primary leptomeningeal sarcomatosis in a 26-year-old patient].

Primary malignant mesenchymal tumours were seen in 2.4 per cent of all autopsy cases with primary CNS-tumours. Primary leptomeningeal sarcomatosis is rare in this group of tumours. We discuss the rare disease on the basis of the case history of a 26-year-old patient.

Adult↗
PubMed1992

[Granulomatous vasculitis--an uncommon manifestation of herpes simplex infection of the central nervous system].

A man died at the age of 50 years, following tentative clinical diagnosis of centrotemporal brain tumour. Strongly pronounced, extended, partially necrotized haemorrhagic inflammation of the leptomeninx, considerably thickened and reaching into cerebral tissue above, was recorded from the cerebral basis on post-mortem examination. The spinal leptomeninx was involved in the inflammatory process. Severe exudative and primary productive pseudotuberculous inflammation was the histological finding, although tuberculous origin could not be confirmed by bacteriological culturing. Polymerase chain reaction with subsequent southern-blot hybridization revealed Herpes simplex virus Type I as the cause of inflammation.

Autopsy↗
PubMed1992

[Dendrite-morphometry of lamina-V-pyramidal cells in premature brain damaged humans--a Golgi study].

Specimens from the area 10 of the frontal cortex collected out of 7 patients with severe mental retardation, aged 3 to 24 years and also 8 non-neuropsychiatric age-matched controls were processed according to the Golgi-Kopsch method. The total length of the apical side-dendrites and of the basal dendrites was measured on layer V pyramidal neurons. Compared with controls the total dendritic length of the apical side-dendrites as well as of the basal dendrites was significant reduced in the affected patients (p less than 0.001). The reduced dendritic length represents perhaps a morphological correlate to the mental dysfunction.

Adolescent↗
PubMed1989

[Innervation anomalies].

The deviation from anatomically described innervation can often occur. It is mainly described on muscles of the limbs. Constant attention should give to this fact during the process of diagnosis of peripheral nerve lesions. Electrophysiological methods (EMG, ENG with blockade of nerve, collision technique and simultaneous lead) can help to detect this anomalies. Double innervation, abnormal innervation and communications among nerves are causes of anomalies of innervation. The fact of communications of fibers among nerves is better called "nerve communication" than "nerve anastomosis". It is vague whether this anomalies of innervation are embryological malformations or reactions of adaptation after different diseases.

Arm↗
PubMed1986

Characterization studies on cadmium-mycophosphatin from the mushroom Agaricus macrosporus.

A low molecular weight Cd-binding phosphoglycoprotein, cadmium-mycophosphatin, has been isolated from the mushroom Agaricus macrosporus. This protein has a molecular weight of 12,000 dalton and contains no sulfur but a high amount of acid amino acids (Glu, Asp), and carbohydrates (glucose, galactose). Cadmium-mycophosphatin has an isoelectric point less than pH 2, binds cadmium with a dissociation constant of KD = 1.59 X 10 M (pKD = 6.8) and is saturated with 13.5 mole Cd/mole, all Cd-binding sites being equivalent. It is suggested that Cd is bound by phosphoserine groups, similar relations being known from calcium-binding proteins in animals. From A. macrosporus four other low-molecular weight glycoproteins have been isolated which contain sulfur and bind cadmium and copper. The biological significance of these Cd-binding proteins is discussed.

Agaricales↗
PubMed1984

[Histochemical-morphometric studies of skeletal muscles in advanced arterial circulation disorders of the extremities].

Biopsies of M. gastrocnemius and Nervus suralis of 12 patients with advanced disturbances of circulation were examined by means of morphometrical and histochemical methods. The histological picture of a neurogenic atrophy of the muscle fibres with partially strong hypertrophy of the slow-twitch fibres was found. The main reaction patterns and the pathogenetic mechanisms are discussed. Alterations in the ratio of type I and type II fibres are described. Fiber type disproportions, i.e. more than 75% type I fibres, may suggest that in hypoxia the type II fibres are more intensely damaged than type I fibres. There are correlations between pathological fibre distribution and the success of vasosurgical treatment.

Adenosine Triphosphatases↗
PubMed1975

Delayed-type hypersensitivity responses to a cell wall fraction of the mycelial phase of Coccidioides immitis.

A skin test-active fraction was isolated from the mycelial-phase cell walls of Coccidioides immitis. This alkali-soluble, water-soluble antigen (C-ASWS) elicited positive reactions in 22 of 24 (92%) of the Coccidioides-sensitized guinea pigs whereas only 14 (54%) of the same guinea pigs reacted to commercial coccidioidin (BioCox). None of the 21 Histoplasma-sensitized guinea pigs cross-reacted with the C-ASWS antigen. Footpad tests in mice actively infected with Coccidioides further established the efficacy of the C-ASWS antigen in eliciting a delayed-type hypersensitivity response. One-microgram doses of C-ASWS produced reactions comparable to 100-mug doses of nondialyzable coccidioidin (Smith's lot 64 D4). The C-ASWS fractions isolated from three different C. immitis strains showed similar reactivity in terms of the number of positive reactions produced in Coccidioides-sensitized guinea pigs. However, the induration responses (diameter in millimeters) elicited by the C-ASWS fraction of one strain were significantly less than those elicited by the C-ASWS fractions of the other two C. immitis strains.

Administration, Intranasal↗