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Biomedical subjects

K Schmidtke

Publications and source records attributed to K Schmidtke.

At least 19 recordsLinked to original sources

Expression of MUPP1 protein in mouse brain.

Localizing cell surface receptors to specific subcellular sites can be crucial for proper functioning. PDZ proteins apparently play central roles in such protein localizations. 5-HT(2C) receptors have previously been shown to interact with MUPP1, a multi PDZ domain protein, in heterologous systems and in rat choroid plexus. We now report the generation and characterization of two independent MUPP1 antisera, which recognise distinct areas of the mouse brain in agreement with previous in-situ hybridization studies. Our results indicate that MUPP1 immunoreactivity co-localizes with 5-HT(2A) or 5-HT(2C) receptor expression in all regions of the mouse brain, including the choroid plexus where 5-HT(2C) receptors are highly enriched.

Animals↗

Heparin treatment in cerebral sinus and venous thrombosis: patients at risk of fatal outcome.

We performed a retrospective analysis of 79 patients with cerebral sinus venous thrombosis, who were treated with a fixed regimen of dose-adjusted intravenous heparin, to determine predictors of a fatal course. The parameters investigated were the state of consciousness and the presence of intracranial haemorrhage (ICH) at the start of heparin treatment, involvement of the internal venous system, mean delay from initial symptom to stupor or coma and from initial symptom to hospital admission, focal neurological deficits, mean intracranial circulation time (ICT) on conventional angiography, and age and sex distribution. Mortality rate was 10% in this series (8/79). There was a strong link between the outcome and the level of vigilance: 53% of the patients with stupor or coma at the start of the heparin therapy died (8/15), whereas all of the 64 patients with no more than mildly impaired vigilance survived (p < 0.00001). Furthermore, mean age and mean ICT were significantly higher in the group of patients who died. There was a statistical trend (p = 0.056) for ICH to be more frequent in cases with fatal outcome, but there was reason to assume that ICH represented an epiphenomenon of a severe course rather than an independent predictor. Other investigated parameters were not linked with a fatal outcome.

Adolescent↗

Changes in cortical activation during mirror reading before and after training: an fMRI study of procedural learning.

The neural correlates of procedural learning were studied using functional magnetic resonance imaging (fMRI) and the mirror reading paradigm. The aim of the study was to investigate a presumed learning-related change of activation in cortical areas that are involved in the performance of a nonmotor skill. Changes in cortical blood oxygenation contrast were recorded in 10 healthy subjects while they alternatively read visually presented single mirror script words and normal script words. Responses in naive subjects were compared to those acquired after training of mirror script reading. The acquisition volume included the motor and premotor cortex, the parietal lobe and the occipital lobe including its inferior aspects. Striate and extrastriate visual areas, associative parietal cortex and the premotor cortex were bilaterally active during normal and mirror script reading. Significantly stronger activation during mirror reading was seen in BA7 and 40 (parietal associative cortex) and in BA6 (corresponding to the frontal eye fields). Simultaneous eye movement recordings indicated that activation in BA6 was related to processing components other than saccade frequency. After training, BA6 and BA7 exhibited a decrease of activation during mirror reading that significantly exceeded nonspecific changes observed in the normal script control condition. The present findings confirm the hypothesis of practice-related decrease of activation in task-related cortical areas during nonmotor procedural learning.

Adult↗

Cognitive frontal lobe dysfunction in obsessive-compulsive disorder.

BACKGROUND: There is evidence that dysfunction within associative frontostriatal circuits represents a feature of obsessive-compulsive disorder (OCD). Previous neuropsychologic studies have yielded diverging results, which may in part be explained by differences in the selection of subjects and methods. The present study focused on the question of cognitive frontal lobe performance in OCD. METHODS: Twenty-nine unmedicated OCD patients were compared to a double-size control group of normal subjects matched individually for age, sex, and intelligence. A series of 12 neuropsychologic tests was applied, most of which are thought to be sensitive to different aspects of cognitive frontal lobe function. RESULTS: OCD patients were unimpaired at tests of abstraction, problem solving, set-shifting, response inhibition, active memory search, and choice reaction speed. Deficits of approximately one standard deviation were observed at timed tests of verbal and nonverbal fluency, attentional processing, and weight sorting. CONCLUSIONS: OCD patients exhibited selective deficits in tasks involving controlled attentional processing and self-guided, spontaneous behavior. We discuss a link between this neuropsychologic profile and dysfunctioning within the anterior cingulate, but not the dorsolateral prefrontal circuit.

Adolescent↗

Early-onset Alzheimer's disease due to mutations of the presenilin-1 gene on chromosome 14: a 7-year follow-up of a patient with a mutation at codon 139.

Mutations in the presenilin-1 gene (PS-1 gene) on chromosome 14 have recently been identified as a cause of familial early-onset Alzheimer's disease (EOAD). To our knowledge, only two German EOAD patients with mutations in the PS-1 gene have been identified thus far. Herein we report the case of a German EOAD patient with a family history of dementia and a missense mutation at codon 139 (M139V) of the PS-1 gene. The patient came to our clinic for the first time when he was 44 years old. During the following 7 years, his Mini-Mental State Examination (MMSE) score dropped from 24 to 0. Myocloni were an early neurological symptom that was already present during the first consultation. We could demonstrate that myoclonic activity was of cortical origin using a back-averaging method. Magnetic resonance imaging (MRI) revealed only slight changes in the early stage of the disease. Follow-up MRI studies showed progression of bitemporal ventricular enlargement and progressive frontal and temporal cortical atrophy. Although the majority of EOAD patients belong to the sporadic (non-genetic) type of AD, early-onset dementia, early myocloni and a familial history of AD should direct attention to the possibility of a genetic form of AD.

Adult↗

Transient global amnesia and migraine. A case control study.

This study examined the putative association of transient global amnesia (TGA) and migraine. 57 TGA patients were compared to a double-size control group of normal subjects. TGA patients who also had migraine were additionally compared to those without migraine and to a second control group of outpatients with migraine only. The prevalence of migraine, and also of episodic tension-type headache, was markedly increased among TGA patients. Precipitants and accompanying vegetative symptoms of TGA and migraine overlapped. However, there was no evidence of an interaction between TGA and migraine, in that the expression of key TGA features was not affected by comorbidity with migraine, and vice versa. The present findings argue against the hypothesis that TGA represents a type of migraine aura or migraine equivalent. They conform to the hypothesis that the two conditions are essentially independent and result from an inherited brain state that disposes to different types of paroxysmal dysregulation, presumably at the level of the brain stem.

Amnesia↗

Cerebral perfusion during transient global amnesia: findings with HMPAO SPECT.

UNLABELLED: The aim of this study was to investigate the pattern of regional cerebral blood flow changes associated with transient global amnesia (TGA). METHODS: HMPAO SPECT was performed in six consecutive patients during the acute phase of TGA. A follow-up SPECT was performed 3-20 wk later in four of the six patients. Semiquantitative analysis of 14 regions of interest, including the basal ganglia and the basal section of the temporal lobes, was performed by comparing patient data with control data obtained from a matched group of healthy subjects. RESULTS: During TGA, unilateral or bilateral hypoperfusion of the temporo-basal region was observed in four patients. Variable hypoperfusion of further cortical areas was observed in five patients. Two patients who exhibited the most marked cortical hypoperfusion also showed striatal and thalamic hypoperfusion. These changes were normalized in the control studies obtained in four patients. CONCLUSION: It remains unclear whether hypoperfusion during TGA represents a primary feature or a sequel of regional brain hypometabolism. Because hypoperfusion is not confined to the temporo-basal region or to the territory of the posterior cerebral artery, it is suggested that the origin of TGA-related changes lies at the level of subcortical structures that project diffusely to the cerebral cortex.

Acute Disease↗

[Follow-up and prognosis of early summer meningoencephalitis].

Sixty-three patients with tick-borne encephalitis were studied for sequelae up to 5 years after the acute illness (median: 12 months, range: 1-44 months). Patients were examined clinically, by neuropsychological testing and by electroencephalography. The clinical presentation during the acute stage was as follows: Meningitis (M,n = 12), Meningoencephalitis (Me,n = 27), Meningoencephalomyelitis (My,n = 15), and Meningoencephaloradiculitis (R,n = 9). A total of 59 patients reported a neurasthenic syndrome after discharge, which correlated with the severity of the acute illness. Twenty patients were not able to work because of reduced stress tolerance, fatigue or an elevated emotional sensitivity, which lasted for 3 months at most. In some patients hypacusis (n = 7), severe dysarthria and dysphagia (n = 4) remained essentially unimproved for years following the acute illness. While in 8/9 patients with radiculitis paresis of the extremities improved well over months to years, improvement was quite limited in all patients with myelitis. In 41/55 patients, investigations by electroencephalography revealed normal findings even within months after acute illness. Persistent cognitive deficits were present only in 7/11 patients with a severe course of disease.

Adolescent↗

Retrograde amnesia: a study of its relation to anterograde amnesia and semantic memory deficits.

This group study of 24 amnesic patients and 40 control subjects examined the hypothesis that retrograde memory deficits result from a combination of two impairment mechanisms: (1) a deficit in the retrieval of contents that is related to dysfunctioning of the hippocampal anterograde memory system, and (2) a deficit in the storage and/or retrieval of contents that is related to concomitant neocortical lesions. Retrograde amnesia was evaluated with the use of new Famous Persons and Autobiographical Memory Tests. The postulated components of retrograde memory impairment were assessed using the Wechsler Memory Scale and a new Semantic Memory Test, respectively. Regression analyses showed that recent episodic autobiography was exclusively related to the hippocampal component, while memory for famous persons and childhood autobiography was related to the neocortical component. In the case of details concerning people of recent fame, both components were identified as independent determinants. The temporal gradient of patients' impairment at the Famous Persons Test was marked for detailed knowledge, but small for overlearned knowledge. The present results thus support the combination hypothesis. They conform to the view that the transition from a hippocampus-dependent to a neocortex-dependent mnemonic representation of new contents is mediated by reiteration, and occurs within 5-10 years.

Adult↗

Progressive hemiparesis in frontal lobe degeneration.

Hemiparesis has rarely been observed in frontal lobe degeneration (FLD). We describe the clinical, neuropsychological and neuroimaging findings of a patient in whom a slowly evolving hemiparesis was the principal symptom of FLD, and of 2 demented patients in whom hemiparesis was an early and prominent symptom. The occurrence of central motor deficits in FLD is reviewed, and a synopsis of the differential diagnosis of hemiparesis in neurodegenerative diseases is given.

Adult↗

Cognitive procedural learning in amnesia.

This group study examined the role of residual declarative memory and task-specific cognitive abilities for cognitive procedural learning in amnesia. 20 amnesic patients and 40 control subjects were studied, using four new cognitive tasks, as well as the Tower of Hanoi and a Mirror Reading task. On the cognitive tasks, but not on Mirror Reading, the learning of amnesic patients was significantly impaired relative to controls. Between- and within-group differences in learning were found to be statistically related to cognitive abilities that are involved in the processing of the procedural tasks. In amnesic patients, significant effects of residual declarative memory on learning scores were not observed, but there was indirect evidence for a role of memory in two tasks. The analysis of the correlative relationship between absolute procedural task performances and cognitive abilities indicated a prolonged dependence on nonspecific intellectual abilities in amnesic patients, suggesting a retarded transition to more advanced stages of skill acquisition.

Adult↗

Characterization and chromosomal assignment of yeast artificial chromosomes containing human 3p13-p21-specific sequence tagged sites.

Human chromosomal region 3p12-p23 is proposed to harbor at least three tumor suppressor genes involved in the development of lung cancer, renal cell carcinoma, and other neoplasias. In order to identify one of these genes we defined sequence tagged sites (STSs) specific for 3p13-p24.2 by analyzing a chromosome 3p14 microdissection library. STSs were used for isolating yeast artificial chromosome (YAC) clones from the Centre d'Etude du Polymorphisme Humain (CEPH) YAC libraries. Thirty-eight YACs were assembled into a contig approximately 2.5 Mb in size spanning the t(3;8) and t(3;6) translocation breakpoints associated with hereditary renal cell carcinoma and hematologic malignancies, respectively. Chromosomal localization and chimeric status of 126 YACs was analyzed by fluorescence in situ hybridization (FISH). The order of 17 YACs determined by double-color FISH was in agreement with the STS-based arrangement of the YAC-contig.

Base Sequence↗

[Functional memory disorders. A study of 25 patients].

Twenty-five patients without relevant organic disease were examined who complained of long-standing memory disturbance, but were free of relevant organic disease and exhibited a test performance that was normal, or reduced by not more than two standard deviations. Cases of amnesia in the context of dissociative reactions were not considered. Symptoms attributed to memory disturbance were differentiated into deficits of new learning, retrograde memory and attention. Typical complaints were forgetting plans on the way to executing them and temporary blockage of material that had been committed to memory. While sex and age were evenly distributed, there was a clear predominance of professionals compared to manual workers. Relevant psychiatric findings or psychiatric diagnoses were present in all cases. The most frequent diagnoses were chronic stress disorder and depressive syndromes. Accompanying psychosomatic symptoms were present in about half of the cases. Wordlist learning scores were in the normal range in the majority of cases, and psychomotor speed scores were in the normal range in nearly all cases. The discussion addresses symptoms, diagnosis, etiology and therapy of functional memory disturbances and examines the relationship to the syndrome of pseudodementia.

Adult↗

Wernicke-Korsakoff syndrome following attempted hanging.

The case of an alcoholic man is reported who survived a suicidal hanging attempt, and subsequently suffered of amnesia, dementia, apathy and behavioural abnormalities. A clinical diagnosis of hypoxic brain damage was made, but upon autopsy six years later, extensive pseudosystematic thalamic degeneration and mammillary body atrophy were found, indicating a status post Wernicke encephalopathy. Precipitation of the disease is attributed to the synergetic effect of cerebral hypoxia/ischemia and thiamine deficiency.

Adult↗

Hartnup syndrome, progressive encephalopathy and allo-albuminaemia. A clinico-pathological case study.

Clinical, biochemical, neuropathological and neurochemical findings in a case of Hartnup syndrome are reported. After initially normal development, the affected girl suffered progressive neuropsychiatric decline with statomotor and mental retardation and intractable seizures and died at the age of 2 years. Postmortem neuropathological and neurochemical investigations showed a combination of extensive neuronal degeneration and cerebral dysmyelination. Pathogenetic hypotheses and the relationship between neuropsychiatric disease and Hartnup syndrome are discussed. Additionally, a fast type bisalbuminaemia present in the girl and her mother is described.

Amino Acids↗

Nervous control of eyelid function. A review of clinical, experimental and pathological data.

This review of the clinical and experimental literature on pre-motor eyelid control, including an analysis of available clinico-pathological reports, suggests support for the following hypotheses: (1) cortex, extrapyramidal motor systems and rostral brainstem structures contribute to the control of the levator palpebrae muscle (LP) in various eyelid functions; (2) though the LP motor nucleus is unpaired, the pre-motor control of LP is at least in part lateralized; (3) signals of the rostral interstitial nucleus of the medial longitudinal fasciculus (MLF) are involved in the control of coordinated lid movements with saccadic up- and downgaze movements; (4) lesions of the medial and/or principal portion of the nuclear complex of the posterior commissure are essential for the production of lid retraction. These structures are assumed to be involved in lid-eye coordination by providing inhibitory modulation of LP motor neuronal activity; (5) the ventral periaqueductal grey is assumed to play a role in the generation of tonic LP motor neuronal activity; (6) neurons of the caudal supraoculomotor area could play a role in the mediation of converging inhibitory inputs onto LP motor neurons.

Blepharoptosis↗