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Biomedical subjects

U Walter

Publications and source records attributed to U Walter.

At least 19 recordsLinked to original sources
PubMed2006

Morphological basis for the spectrum of clinical deficits in spinocerebellar ataxia 17 (SCA17).

Spinocerebellar ataxia 17 (SCA17) is a rare genetic disorder characterized by cerebellar, extrapyramidal, pyramidal as well as psychiatric signs. The pathoanatomical basis of this disorder is still not well known. A total of 12 patients and 12 age- and sex-matched controls were examined by in vivo MRI voxel-based morphometry (VBM). Besides general patterns of disease-related brain atrophy, characteristic syndrome-related morphological changes in SCA17 patients were studied. In comparison with normal controls, SCA17 patients showed a pattern of degeneration of the grey matter centred around mesial cerebellar structures, occipito-parietal structures, the anterior putamen bilaterally, the thalamus and other parts of the motor network, reflecting the cerebellar, pyramidal and extrapyramidal signs. A correlation analysis revealed a clear association between the clinical cerebellar, extrapyramidal and psychiatric scores and degeneration in specific areas. Two degeneration patterns were found as follows: regarding motor dysfunction, atrophy of the grey matter involved mainly the cerebellum and other motor networks, in particular the basal ganglia. In contrast, correlations with psychiatric scores revealed grey matter degeneration patterns in the frontal and temporal lobe, the cuneus and cingulum. Most interestingly, there was a highly significant correlation between the clinical Mini-Mental State Examination scores and atrophy of the nucleus accumbens, probably accounting for the leading psychiatric signs.

Adult↗
PubMed2006

[Morbidity and health in old age. A challenge for prevention and health care].

Due to chronic illness and multimorbidity, the physical and psychosocial impairments increase significantly in the second half of life. Even though the health condition of the elderly has improved in recent years, the potential for prevention in older people is still undervalued. On the basis of surveys, data from the Association of CHI Physicians and health insurance data, this article provides a review of health and health behaviour of the elderly in Germany. It aims to point out areas of particular relevance for prevention and preventive approaches. Strategies that consider mental and social aspects of aging beside the physical ones are necessary. Systematic, personal and professional factors still inhibit the realisation of these strategies. In this context, doctors and nurses are particularly important as primary professional contact persons for the target group. However, prevention and health promotion in that age group are social tasks, which need the appropriate involvement of further professionals and an explicit political agenda setting.

Aged↗
PubMed2006

A neuronal nitric oxide synthase (NOS-I) haplotype associated with schizophrenia modifies prefrontal cortex function.

Nitric oxide (NO) is a gaseous neurotransmitter thought to play important roles in several behavioral domains. On a neurobiological level, NO acts as the second messenger of the N-methyl-D-aspartate receptor and interacts with both the dopaminergic as well as the serotonergic system. Thus, NO is a promising candidate molecule in the pathogenesis of endogenous psychoses and a potential target in their treatment. Furthermore, the chromosomal locus of the gene for the NO-producing enzyme NOS-I, 12q24.2, represents a major linkage hot spot for schizophrenic and bipolar disorder. To investigate whether the gene encoding NOS-I (NOS1) conveys to the genetic risk for those diseases, five NOS1 polymorphisms as well as a NOS1 mini-haplotype, consisting of two functional polymorphisms located in the transcriptional control region of NOS1, were examined in 195 chronic schizophrenic, 72 bipolar-I patients and 286 controls. Single-marker association analysis showed that the exon 1c promoter polymorphism was linked to schizophrenia (SCZ), whereas synonymous coding region polymorphisms were not associated with disease. Long promoter alleles of the repeat polymorphism were associated with less severe psychopathology. Analysis of the mini-haplotype also revealed a significant association with SCZ. Mutational screening did not detect novel exonic polymorphisms in patients, suggesting that regulatory rather than coding variants convey the genetic risk on psychosis. Finally, promoter polymorphisms impacted on prefrontal functioning as assessed by neuropsychological testing and electrophysiological parameters elicited by a Go-Nogo paradigm in 48 patients (continuous performance test). Collectively these findings suggest that regulatory polymorphisms of NOS1 contribute to the genetic risk for SCZ, and modulate prefrontal brain functioning.

Adult↗
PubMed2006

Application of transcranial sonography in extrapyramidal disorders: updated recommendations.

Transcranial sonography (TCS) has been proven to be a valuable tool in the diagnosis and differential diagnosis of extrapyramidal disorders, supplementing clinical and pathophysiological information that may be obtained by other neuroimaging techniques. Growing interest and increased application of TCS in extrapyramidal disorders require adherence to standardised principles concerning examination procedure and parameter settings of the ultrasound machine in order to ensure comparable results. This article provides an overview of these principles and typical findings in distinct extrapyramidal disorders.

Basal Ganglia Diseases↗
PubMed2006

[Effective prevention through nutritional and food additives: barriers and resistance].

The population-wide and individual preventive potentials of nutritional and food additives such as vitamins and trace elements are generally accepted in the international literature. Iodisation and fluoridation were and are a main focus of activity. The enrichment of food with folic acid is also partly population-related. Until now, however, the theoretical possibilities of nutritional supplementations have not been fully exploited. Various barriers and resistances arise in programme development and implementation. Interviews with key stakeholders and community groups can clarify decade-long discussions in the literature and the media. The study on hand is based on a structural analysis. It shows the various arguments as well as beneficial and impeding factors for a population-wide prevention programme, for specific target groups and individuals. The findings of this research could also be applied to other Public Health challenges.

Attitude to Health↗
PubMed2006

Factor VIII is a positive regulator of platelet function.

FVIII is an important cofactor in the tenase coagulation factor complex, lack of FVIII causes severe bleeding, whereas high FVIII levels seem to be associated with venous and arterial thromboembolism. Resting platelets do not bind FVIII, but activated platelets bind unactivated FVIII if vWF is not present. We investigated a possible influence of platelet bound FVIII on platelet function itself as it is unclear if there is a direct effect of FVIII on platelet function. The influence of FVIII on platelet function was investigated by flow cytometric analysis of P-selectin expression (CD62P) and PAC-1 binding before and after submaximal stimulation with TRAP-6 (5 microM final concentration), by confocal microscopy and by platelet aggregometry. For flow cytometry and confocal microscopy, washed platelets were incubated with human recombinant FVIII for 5 min at 37 degrees C. Analysis of platelet surface area was measured by computerized image analysis. Treatment with FVIII only caused no changes in P-selectin expression or PAC-1 binding, respectively. Stimulation of platelets with TRAP-6 increased the expression of P-selectin (445%) and PAC-1 binding (934%) as expected. These effects were further increased when platelets were stimulated with TRAP-6 and FVIII (P-selectin 499%, difference not significant; PAC-1 1626%, P < 0.05. Values were expressed in%, related to unstimulated, buffer treated platelets). Platelet spreading on fibrinogen was significantly increased when platelets were treated with FVIII and TRAP-6 compared to TRAP-6 alone (368 vs. 307 average pixel/platelet, P<0.05). In addition platelet aggregation was enhanced when platelets were stimulated with FVIII and TRAP-6 compared to TRAP-6 alone. FVIII can act as a positive regulator of platelet function in TRAP-co-stimulated platelets. We hypothesize that FVIII induced increase in platelet activation might contribute to venous and even arterial thrombus formation in patients with high FVIII levels.

Dual Specificity Phosphatase 2↗
PubMed2006

Overactive bladder in Parkinson's disease: alteration of brainstem raphe detected by transcranial sonography.

Urinary dysfunction is very common in idiopathic Parkinson's disease (PD) and manifests primarily with symptoms of overactive bladder (OAB). Affection of central serotonergic systems has been suggested to play a role in OAB. The objective of this study was to evaluate whether in PD patients with OAB symptoms a specific alteration of the brainstem raphe (BR), which contains serotonergic neurons, can be detected with transcranial sonography (TCS). Of 116 PD patients enrolled, 19 had PD-related OAB symptoms (OAB+) unlike remaining 97 patients (OAB-). Patients were examined by a sonographer blinded to the clinical data. Reduced echogenicity of BR was found in 12 (63%) OAB+ patients but only in 18 (19%) of 93 assessable OAB- patients (Mann-Whitney U-test, P < 0.001). In OAB+ patients, lower raphe echogenicity score was associated with longer duration of OAB symptoms (anova, P = 0.033). Other TCS findings such as echogenicity of substantia nigra, thalami, lenticular and caudate nuclei, and widths of third and lateral ventricles did not differ between OAB+ and OAB- patients. TCS findings suggest a pathogenetic role of BR in OAB related to PD. Alterations may reflect disturbance of its central serotonergic system.

Adult↗
PubMed2005

[Physical (in)activity in childhood and adolescence].

In the last two decades in Germany and other countries physical activity of children and adolescents declined while sedentary lifestyle increased. Physical inactivity in childhood and youth is related with coronary heart disease risk factors and higher prevalence of obesity. International recommendations suggest daily 60 minutes or more moderate to vigorous physical activity and less than 2 hours sedentary activity in leisure.

Adolescent↗
PubMed2005

Sonographic detection of basal ganglia lesions in asymptomatic and symptomatic Wilson disease.

OBJECTIVE: To investigate whether transcranial brain parenchyma sonography (TCS) detects basal ganglia abnormalities in asymptomatic and symptomatic patients with Wilson disease (WD) and whether findings correlate with disease severity. METHODS: Twenty-one patients with WD with (n = 18) or without (n = 3) neurologic symptoms were investigated. Disease severity was assessed by three independent neurologists using a WD rating scale (WDRS) with the items dysarthria, akinesia, ataxia, tremor, and dystonia; the raters' median score was used for further analysis. Basal ganglia TCS was performed according to a standardized protocol. RESULTS: TCS revealed lenticular nucleus (LN) hyperechogenicity in all assessable neurologically symptomatic and in two of the three asymptomatic patients. Size of LN hyperechogenic area correlated with the WDRS score (Spearman correlation, rho = 0.604, p = 0.006), as did the size of thalamus hyperechogenic area (n = 7, rho = 0.891, p = 0.007), the width of third ventricle (n = 21, rho = 0.613, p = 0.003), and the width of lateral ventricles (n = 20, rho = 0.642, p < 0.001). Substantia nigra hyperechogenicity, detected in 10 patients, did not correlate with disease severity. There was no correlation between age at disease onset or disease duration and any TCS finding. Of the 19 patients with LN hyperechogenicity, only 12 showed abnormal LN on MRI. CONCLUSIONS: Transcranial brain parenchyma sonography (TCS) detects lenticular nucleus hyperechogenicity, likely to be caused by copper accumulation, in neurologically symptomatic and asymptomatic Wilson disease (WD). TCS findings correlate with disease severity. TCS appears a promising tool for disease monitoring in WD.

Adult↗
PubMed2005

[Electrochemical properties of biocompatible material hardness modifications on titanium and steel under mechanical loads].

Friction corrosion may appear between different implant components or between implant and hard tissue. The sliding micro movements induce fretting wear corrosion and have been recently reported as a cause of joint prostheses failure. A surface coating is desirable, that retains the mechanical properties of the substrate, offers good biocompatibility and improves the fretting corrosion resistance. In this study it could be demonstrated that tantalum and niobium coatings fulfill the requirements. On titanium substrates the coating decreases the abrasion against PMMA, an orthopedic relevant material. Furthermore, in the case of medical steel substrates the biocompatibility and the corrosion properties are improved. The better abrasion-resistance is minimizing the release of allergological critical particles like nickel and chromium.

Coated Materials, Biocompatible↗
PubMed2004

Ceruloplasmin gene variations and substantia nigra hyperechogenicity in Parkinson disease.

BACKGROUND: Transcranial ultrasound may be used to detect increased iron levels of the substantia nigra (SN) in patients with Parkinson disease (PD) and in control subjects. It is not known whether iron accumulation in PD is a primary or secondary phenomenon. However, sequence variations in genes involved in iron metabolism have been linked to basal ganglia disorders. One of these is ceruloplasmin (Cp), which is vitally involved in iron transport across the cell membrane. METHODS: One hundred seventy-six patients with PD according to the UK Brain Bank criteria and 180 ethnically matched control subjects, who were previously examined for SN iron signal changes by transcranial ultrasound, were examined for mutations in the Cp gene using denaturing high-performance liquid chromatography and subsequent sequencing for verification of unequivocal signals. Immunohistochemistry of PD midbrains was performed to examine the presence of Cp in Lewy bodies. RESULTS: Five novel missense variations were detected. One of these (I63T) was found in a single PD patient. A known variation (D554E) was significantly associated with PD and the ultrasound marker for increased SN iron levels. Moreover, a third sequence variation (R793H) was found to segregate with the ultrasound marker for increased iron levels in patients and control subjects. Immunohistochemistry demonstrated that Cp co-localizes with Lewy bodies in PD. CONCLUSIONS: Detection of sequence variations in a single Parkinson disease (PD) patient or associated with the ultrasound marker for increased substantia nigra iron levels and the presence of ceruloplasmin (Cp) immunoreactivity in Lewy bodies underline a suspected role for Cp in the pathogenesis of PD. Further functional analyses are warranted to investigate whether these variations are causally linked to the complex pathogenesis of PD in a subset of cases.

Aged↗
PubMed2004

Sonographic discrimination of corticobasal degeneration vs progressive supranuclear palsy.

OBJECTIVE: To study the use of brain parenchyma sonography (BPS) in discriminating between patients with corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). METHODS: Thirteen patients with PSP and eight with CBD were studied with BPS according to a standardized protocol. RESULTS: Seven (88%) of the eight CBD patients showed marked hyperechogenicity of the substantia nigra (SN) but none of eleven PSP patients (Mann-Whitney U test, p < 0.001). This finding indicated CBD with a positive predictive value of 100%. Marked dilatation of the third ventricle (width > 10 mm) was found in 10 (83%) of 12 PSP patients, but in none of the CBD patients (p < 0.005). BPS measurements of ventricle widths closely matched MRI measurements (Pearson correlation, r = 0.90, p < 0.001). The presence of at least one of the BPS findings 1) marked SN hyperechogenicity and 2) third-ventricle width < 10 mm indicated CBD with a sensitivity of 100%, a specificity of 83%, and a positive predictive value of 80%. Other BPS findings such as echogenicity of lentiform and caudate nuclei and widths of the frontal horns did not discriminate between CBD and PSP. One PSP patient could not be assessed because of insufficient acoustic temporal bone windows. CONCLUSIONS: Substantia nigra hyperechogenicity, reported earlier as characteristic brain parenchyma sonography finding in idiopathic Parkinson disease, is also typical for corticobasal degeneration.

Aged↗
PubMed2004

Vasodilator-stimulated phosphoprotein is a substrate for protein kinase C.

Vasodilator-stimulated phosphoprotein (VASP), an actin binding protein localized to areas of focal contacts, is a substrate for the cyclic adenosine monophosphate/cyclic guanosine monophosphate (cAMP/cGMP)-dependent protein kinases (PKA, PKG). In this study, we show that serum stimulation of vascular smooth muscle cells (SMCs) induces VASP phosphorylation on Ser157, in a mechanism not dependent on PKA or PKG. We tested the possibility that protein kinase C (PKC), a regulator of cytoskeletal function, is involved. PKC inhibition or down-regulation prevented serum-induced phosphorylation of VASP at Ser157 in rat vascular SMCs. Additionally, recombinant PKCalpha directly phosphorylated Ser157 on VASP. In summary, our data support the hypothesis that PKC phosphorylates VASP and mediates serum-induced VASP regulation.

Animals↗
PubMed2004

[Population-related and individual prevention. Strategies and effectiveness].

In the German health system up to now prevention takes only a marginal position. To tap the full preventive potential in future population-based and risk group-strategies must be systematically extended, combined with individual strategies in clinical preventive medicine and integrated in health care. This report gives international and national examples for these strategies and shows that such preventive programmes could be effective as well cost-effective.

Forecasting↗
PubMed2004

Screening for mutations of the IRP2 gene in Parkinson's disease patients with hyperechogenicity of the substantia nigra.

IRP2 plays an important role in brain iron metabolism. We recently identified an increased amount of iron in patients with Parkinson's disease (PD) and hyperchogenicity of the substantia nigra (SN). Therefore, the IRP2 gene was screened for mutations in 176 PD patients with increased echogenicity of the SN. We identified one non-synonymous polymorphism (I888V) in exon 21 and a -88C > T polymorphism in the promoter region of IRP2 at similar frequencies in patients and controls without increased SN iron levels. In one patient a -74C > T variation was found which was not present in the control group. Our data indicate that mutations in the IRP2 gene are not a common cause of PD associated with SN iron accumulation.

Aged↗
PubMed2004

[Observance of legal preventive measures and implications for a comprehensive prevention law].

The observance and realisation of a variety of prevention laws in different spheres was analysed to deal more extensively with the problem of a new comprehensive prevention law. The analysis was based on a study of the literature and on invited statements by experts, as well as on interviews conducted according to guidelines. The observance and implication of existing laws by statutory bodies differs noticeably according to prevailing traditions and individual interpretations of key concepts. In all the spheres we noticed a potential for supporting and optimising prevention. The mandatory next step would be to standardise the plethora of terms and to discuss the understanding of prevention. It is also imperative to realise on-target cooperation, to define the tasks to be accomplished, and to determine to whom they should be delegated. The financing procedure must also be determined. Modification and supplementation of existing laws would be meaningful in some cases. A new specific and comprehensive prevention law would increase the status of prevention in the German public health system and link up the involved institutions more effectively.

Comprehensive Health Care↗