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Biomedical subjects

K Wetzel

Publications and source records attributed to K Wetzel.

At least 19 recordsLinked to original sources
PubMed2004

Isolated bacterial meningitis as the key syndrome of infective endocarditis.

BACKGROUND: Bacterial meningitis is an unusual first manifestation but a major complication of infective endocarditis. PATIENTS AND METHODS: We present three well documented cases of isolated bacterial meningitis in endocarditis. Against this background we review the literature. RESULTS: All patients presented with bacterial meningitis. Staphylococcus aureus was isolated in blood cultures of all patients, but was found only in the cerebrospinal fluid (CSF) of one patient. The underlying endocarditis was confirmed histologically in all three cases. Two patients recovered completely and one died. CONCLUSION: An extensive search for endocarditis is recommended in every case of an unusual isolate in bacterial meningitis whether it is isolated from blood or CSF.

Aged↗
PubMed2001

Cell therapy attenuates deleterious ventricular remodeling and improves cardiac performance after myocardial infarction.

BACKGROUND: Myocardial infarction (MI) promotes deleterious remodeling of the myocardium, resulting in ventricular dilation and pump dysfunction. We examined whether supplementing infarcted myocardium with skeletal myoblasts would (1) result in viable myoblast implants, (2) attenuate deleterious remodeling, and (3) enhance in vivo and ex vivo contractile performance. METHODS AND RESULTS: Experimental MI was induced by 1-hour coronary ligation followed by reperfusion in adult male Lewis rats. One week after MI, 10(6) myoblasts were injected directly into the infarct region. Three groups of animals were studied at 3 and 6 weeks after cell therapy: noninfarcted control (control), MI plus sham injection (MI), and MI plus cell injection (MI+cell). In vivo cardiac function was assessed by maximum exercise capacity testing and ex vivo function was determined by pressure-volume curves obtained from isolated, red cell-perfused, balloon-in-left ventricle (LV) hearts. MI and MI+cell hearts had indistinguishable infarct sizes of approximately 30% of the LV. At 3 and 6 weeks after cell therapy, 92% (13 of 14) of MI+cell hearts showed evidence of myoblast graft survival. MI+cell hearts exhibited attenuation of global ventricular dilation and reduced septum-to-free wall diameter compared with MI hearts not receiving cell therapy. Furthermore, cell therapy improved both post-MI in vivo exercise capacity and ex vivo LV systolic pressures. CONCLUSIONS: Implanted skeletal myoblasts form viable grafts in infarcted myocardium, resulting in enhanced post-MI exercise capacity and contractile function and attenuated ventricular dilation. These data illustrate that syngeneic myoblast implantation after MI improves both in vivo and ex vivo indexes of global ventricular dysfunction and deleterious remodeling and suggests that cellular implantation may be beneficial after MI.

Animals↗
PubMed2001

Detection of Giardia lamblia and Entamoeba histolytica in stool samples by two enzyme immunoassays.

Two commercially produced enzyme immunoassays (EIAs) to detect antigens of Giardia lamblia and Entamoeba histolytica in stool specimens were evaluated. A total of 276 stool specimens were collected from patients who presented with various medical complaints in the outpatient clinic of the Department of Infectious Diseases and Tropical Medicine, University of Munich. Every specimen was examined by conventional microscopy and tested by both EIA kits. When microscopy was used as the reference standard, the EIA kit detecting Giardia lamblia showed a sensitivity of 100% and a specificity of 99.6%. The EIA kit detecting Entamoeba histolytica had a sensitivity of 81.8% and a specificity of 99.2%. Both tests showed no cross-reactivity with other intestinal protozoa. Antigen detection by EIA has the potential to become a valuable tool capable of making stool diagnostics more effective, although it should not be considered as a replacement for microscopic examination, since other potential pathogens could otherwise escape detection.

Animals↗
PubMed1998

Sequence characteristics, subcellular localization, and substrate specificity of DYRK-related kinases, a novel family of dual specificity protein kinases.

DYRK1 is a dual specificity protein kinase presumably involved in brain development. Here we show that the kinase belongs to a new family of protein kinases comprising at least seven mammalian isoforms (DYRK1A, DYRK1B, DYRK1C, DYRK2, DYRK3, DYRK4A, and DYRK4B), the yeast homolog Yak1p, and the Drosophila kinase minibrain (MNB). In rat tissues, DYRK1A is expressed ubiquitously, whereas transcripts for DYRK1B, DYRK2, DYRK3, and DYRK4 were detected predominantly in testes of adult but not prepuberal rats. By fluorescence microscopy and subcellular fractionation, a green fluorescent protein (GFP) fusion protein of DYRK1A was found to accumulate in the nucleus of transfected COS-7 and HEK293 cells, whereas GFP-DYRK2 was predominantly detected in the cytoplasm. DYRK1A exhibited a punctate pattern of GFP fluorescence inside the nucleus and was co-purified with the nuclear matrix. Analysis of GFP-DYRK1A deletion constructs showed that the nuclear localization of DYRK1A was mediated by its nuclear targeting signal (amino acids 105-139) but that its characteristic subnuclear distribution depended on additional N-terminal elements (amino acids 1-104). When expressed in Escherichia coli, DYRK1A, DYRK2, DYRK3, MNB, and Yak1p catalyzed their autophosphorylation on tyrosine residues. The kinases differed in their substrate specificity in that DYRK2 and DYRK3, but not DYRK1A and MNB, catalyzed phosphorylation of histone H2B. The heterogeneity of their subcellular localization and substrate specificity suggests that the kinases are involved in different cellular functions.

Amino Acid Sequence↗
PubMed1998

Cholinergic modulation of neuronal responses to cholecystokinin in anesthetized rats.

The aim of this study was to investigate whether the effects of the neuropeptide cholecystokinin on neuronal firing can be changed by acetylcholine in various structures of the brain. Single unit activity was extracellularly recorded in rats anesthetized with urethane. The neurons were located in several nuclei of the thalamus, the basal ganglia and the cerebral cortex. Neurons responding to the sulfated octapeptide of cholecystokinin (CCK-8S) were mainly activated by the drug [Wilcoxon test (Wt) p < 0.0001, n=113]. Thalamic neurons could also increase the number of burst discharges (Wt p < 0.005, n=39). Iontophoretically administered acetylcholine could reduce the activating effects of CCK-8S on firing and burst discharges. In its presence, even inhibitory effects of CCK-8S predominated (Wt p < 0.0001, n=113). The suppressive action seemed not to depend on the direction of the effect of acetylcholine itself and concerned neurons of all locations studied. Atropine could diminish or block the suppressive action of acetylcholine. In the presence of both drugs, CCK-8S mainly activated the neurons (Wt p < 0.005, n=43). Atropine itself did not significantly change the responses to CCK-8S (Wt p > 0.05). It can be concluded that cholecystokinin may reduce neuronal firing instead of increasing it during activation of the cholinergic system.

Acetylcholine↗
PubMed1997

Neostriatal neurons of rats can be influenced by cholecystokinin-A receptor agonists.

The present study investigated the effects of agonists of the neuropeptide cholecystokinin (CCK) on neostriatal neurons in order to confirm the existence of CCK-A receptors in the rat caudate-putamen. Single unit activity was recorded in rats anaesthetized with urethane. The CCK-A receptor agonists A-71378 (desamino-Tyr(SO3H)-Nle-Gly-Trp-Nle-(N-methyl)Asp-Phe-NH2), and A-71623 (Boc-Trp-Lys(epsilon-N-2-methylphenylamino-carbonyl)-Asp-(N-methyl )Phe-NH2, as well as the CCK-B receptor agonist Suc-CCK-4 (Suc-Trp-(N-methyl)Nle-Asp-Phe-NH2) were iontophoretically administered with multibarrel capillaries. About one-third of the neurons responded to the CCK-A receptor agonists. Excitatory effects predominated. The CCK-B receptor agonist also induced mainly increases in the neuronal firing. Several neurons were affected by both types of agonists. The results suggest that in the rat neostriatum not only CCK-B receptors, but also CCK-A receptors seem to mediate the effects of cholecystokinin.

Animals↗
PubMed1997

Effects of cholecystokinin agonists on striatal neurons are reduced by acetylcholine.

The present study investigated whether acetylcholine, a transmitter of striatal interneurons, modulates responses of neostriatal neurons to agonists of the neuropeptide cholecystokinin (CCK). Single unit activity was recorded in rats anesthetized with urethane. Acetylcholine and CCK agonists (the CCKA receptor agonists A-71378 and A-71623; the CCKB receptor agonist Suc-CCK-4) were iontophoretically administered alone and in combination. The CCK agonists excited about one third of the neurons. The excitatory effects of both the CCKB and the CCKA receptor agonists were mainly reduced or changed to suppression of activity by acetylcholine (Wilcoxon test p < 0.001). Atropine did not significantly change the neuronal responses to the CCK agonists. The suppressive action of acetylcholine could be diminished by additional administration of atropine. The results suggest that the modulatory action of cholecystokinin does not only depend on the actual state of excitability in striatal neurons, but could be changed by acetylcholine released from interneurons.

Acetylcholine↗
PubMed1997

Fetal pig neural cells as a restorative therapy for neurodegenerative disease.

With proper immunosuppression, interspecies transplantation of porcine as well as other species of neural cells survive, mature, and integrate into the host in a manner which reconstructs much of the appropriate neural circuitry. These transplants have been shown to alleviate many of the symptoms of various disorders of the central nervous system. In this study, we addressed immunological and maturation issues with regards to intracerebral transplantation of fetal porcine neural cells. First, we compared fetal neural xenograft survival in athymic nude rats versus rats immunosuppressed with cyclosporin A and found that there is little discernible difference between porcine grafts in the 2 recipients. We also found that ectopic transplantation of cells isolated from the porcine striatal primordium can survive and develop into grafts composed of both neuronal and glial phenotypes within the rat hippocampus. This fact raises the possibility that cells of a particular neurotransmitter type (e.g., GABAergic cells) developing from the striatal precursor cells can be transplanted outside the striatum of the adult brain and have physiological effects.

Animals↗
PubMed1996

Speech-recognizing computers: a written-communication tool for students with learning disabilities?

Students with specific learning disabilities (LD) in written composition may experience difficulties that restrict their ability to demonstrate in writing what they know and can communicate orally. Voice-input technology now allows users to speak into a microphone and have their words appear on a computer screen in a word processing format, ready for revision and editing. This exploratory study reports the efforts of one sixth-grade student to learn to use this technology to assist written communication. The findings suggest that the technology holds promise for students with LD when it is refined to allow less difficulty in using it.

Child↗
PubMed1995

Cholecystokinin excites neostriatal neurons in rats via CCKA or CCKB receptors.

The effect of iontophoretically applied cholecystokinin (CCK) on neurons of the neostriatum was studied in rats anaesthetized with urethane. The most frequently observed effect of the sulphated octapeptide (CCK-8S) on striatal neurons was excitation. Spontaneously active neurons responded more often to CCK-8S than quiescent cells. Silent, primarily non-responsive neurons could often be stimulated with CCK-8S using glutamate to induce an ongoing discharge. Thus, 45.8% of the 177 neurons studied changed their discharge rate by more than 30%. Certain CCK receptor antagonists could prevent the effect of CCK-8S, fully or at least partly, in the majority of CCK-responsive neurons. The data suggest that cholecystokinin modulates the firing of active neostriatal neurons via the CCKA or the CCKB receptor type. Furthermore, we compared neuronal responses to glutamate with those recorded during concomitant administration of CCK-8S in order to study the interaction of both transmitters, which may be colocalized in striatal afferents. CCK-8S mainly enhanced the excitatory effect of glutamate on striatal neurons, but in several neurons the response to glutamate was reduced. The CCKB receptor antagonist could prevent CCK-8S from increasing the glutamate-induced activation.

Animals↗
PubMed1990

The work attitudes of full-time and part-time registered nurses.

As the use of part-time nurses increases, so does concern about their work-related attitudes. This empirical study finds minor differences between part-time and full-time nurses' attitudes and concludes that part-time nursing employment should not adversely affect health care goals.

Adult↗
PubMed1990

[Neuropsychologically oriented examination of preschool children. Practical consequences].

A random sample of the neuropediatric patients in our department, i.e. pre-school children of normal intelligence with brain injuries or suspected brain injuries, was investigated using a neuropsychological test system and compared with an age-standardized population of uninjured children. The results clearly indicate that is possible to register partial disorders of performance achievement already at the pre-school age. These disorders have special relevance for success at school, particularly in the initial stages. Practicable psychological-diagnostic possibilities and consequences for the care of such children have been derived from this study.

Brain Damage, Chronic↗
PubMed1990

[Prognostic value of hyperkinetic syndrome in children with epilepsy].

In a retrospective study the data of 43 children suffering from epilepsy were analysed. The first epileptic seizure was observed in all patients before the age of 6 years. The relationship between behavioral disturbances with hyperactivity, developmental respectively intellectual test scores, and efficiency of antileptic drug therapy have been investigated. Psychological testings were performed two times, at first after the start of drug therapy, and a second time after a period of 1 year 11 months in average. There were behavioral disturbances with hyperactivity in 20 patients. The epileptic seizures were intractable in 26 patients. The developmental respectively intellectual test scores have decreased to values below 85 in 7 patients with and 3 patients without hyperactivity. There was a decline by more than 10 points of the IQ score between first and second psychological testings in 16 patients with and 4 patients without hyperactivity, respectively in 17 patients with intractable seizures, but in one child only with prompt cessation of epileptic seizures. An increasing retardation of mental development was seen in children with hyperactivity at the start of seizures, in children with intractable seizures, but especially in patients with a combination of intractable seizures and hyperactivity.

Anticonvulsants↗
PubMed1980

[Current state and perspectives of the use of the 15N-tracer technic in gastroenterologic studies].

The importance of 15N as tracer in medical research is increasing. Since 1965 many results were obtained in cooperation of surgeons (Surgical clinic of Karl-Marx-University; Bezirkskrankenhaus St. Georg, Leipzig) and coworkers of Central Institute of Isotope and Radiation research. Using 3 test models (15N-labelled amino acid solution, permanent infused; 15N-labelled glycine, given as one single dose; 15N-labelled casein, oral given) healthy persons, patients in stress condition and after gastric operations and rats after performing several types of gastric operations were studied. Possibilities of calculations with mathematical models are shown.

Amino Acids↗