Organische Feldeffekttransistoren als Transducer in der Biosensorik (Organic Field Effect Transistors as Biosensors)

In diesem Beitrag wird der Einsatz neuartiger Sensortypen für die medizinische Diagnostik beschrieben. Diese Sensoren sollen komplett organisch sein und auf dem Prinzip des Feldeffekttransistors basieren. Als Modellsystem für die Anwendung in der Biosensorik soll die Einsatzmöglichkeit dieser Sensoren in der nicht-invasiven Diagnostik der Helicobacter-pylori-Infektion überprüft werden.

Use of complementary and alternative medicine in patients suffering from primary headache disorders

Complementary and alternative medicine (CAM) is increasingly common in the treatment of primary headache disorders despite lack of evidence for efficacy in most modalities. A systematic questionnaire-based survey of CAM therapy was conducted in 432 patients who attended seven tertiary headache out-patient clinics in Germany and Austria. Use of CAM was reported by the majority (81.7%) of patients. Most frequently used CAM treatments were acupuncture (58.3%), massage (46.1%) and relaxation techniques (42.4%). Use was motivated by 'to leave nothing undone' (63.7%) and 'to be active against the disease' (55.6%). Compared with non-users, CAM users were of higher age, showed a longer duration of disease, a higher percentage of chronification, less intensity of headache, were more satisfied with conventional prophylaxis and showed greater willingness to gather information about headaches. There were no differences with respect to gender, headache diagnoses, headache-specific disability, education, income, religious attitudes or satisfaction with conventional attack therapy. A higher number of headache days, longer duration of headache treatment, higher personal costs, and use of CAM for other diseases predicted a higher number of used CAM treatments. This study confirms that CAM is widely used among primary headache patients, mostly in combination with standard care.

Head of the caudate nucleus is most vulnerable in chorea-acanthocytosis: a voxel-based morphometry study

Chorea-acanthocytosis (ChAc; OMIM 200150) is a rare autosomal recessive disease with dysfunction of the erythrocyte membrane, presenting with acanthocytes and neurological manifestations characterized by progressive hyperkinesias (chorea, dystonia) and neuropsychological impairment. Damage to the basal ganglia was described previously in neuropathological and neuroimaging investigations. We analyzed high-resolution MRI of six ChAc patients with mutations in the VPS13A gene (median age, 37 years; mean time since clinical onset, 13 years) with respect to regional atrophy by use of the observer-independent technique of voxel-based morphometry in comparison to 15 age-matched healthy controls. Additionally, global brain atrophy was determined using the standardized brain parenchymal fraction (BPF) method. A robust regional reduction of gray matter density was observed in the head of the caudate nucleus bilaterally and was nearly symmetrical (P < 0.001, corrected for small volumes). No additional gray matter changes were found. In the BPF analysis, there was no significant global brain atrophy. The predilection of atrophy in the head of the caudate nucleus, as suggested by our results, argues for a particular vulnerability of this part of the striatum in ChAc and is in agreement with pronounced neuropsychological disturbances that are thought to rely on these regions.

[Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy]

A 32-year-old patient presented with presenile dementia syndrome and complex-partial seizures. The dementia was preceded by recurrent bone pain which led to surgical intervention for ossear cysts. Computed tomography revealed intracerebral calcification and marked brain atrophy. Clinical, radiological, genetic, and histopathological features of PLOSL disease are discussed in the differential diagnosis of presenile dementia and basal ganglia calcification.

Testicular dose and hormonal changes after radiotherapy of rectal cancer

BACKGROUND AND PURPOSE

To measure the dose received by the testicles during radiotherapy for rectal cancer and to determine the contribution of each field of the pelvic box and the relevance for hormonal status.

MATERIALS AND METHODS

In 11 patients (mean age 55.2 years) testicular doses were measured with an ionisation chamber between 7 and 10 times during the course of pelvic radiotherapy (50 Gy) for rectal carcinoma. Before and several months after radiotherapy luteinizing hormone, follicle stimulating hormone and total testosterone serum levels were determined.

RESULTS

The mean cumulative radiation exposure to the testicles was 3.56 Gy (0.7-8.4 Gy; 7.1% of the prescribed dose). Seventy-three percent received more than 2 Gy to the testicles. Fifty-eight percent of the measured dose was contributed by the p.a. field, 30% by the a.p. field and 12% by the lateral fields. Mean LH and FSH levels were significantly increased after therapy (350%/185% of the pre-treatment values), testosterone levels decreased to 78%. No correlation could be found between changes of hormones and doses to the testis, probably due to the low number of evaluated patients.

CONCLUSIONS

Radiotherapy of rectal carcinoma causes significant damage to the testis, as shown by increased levels of gonadotropins after radiotherapy. Most of the gonadal dose is delivered by the p.a. field, due to the divergence of the p.a. beam towards the testicles. The reduction in testosterone level may be of clinical concern. Patients who will receive radiotherapy for rectal carcinoma must be instructed about a high risk of permanent infertility, and the risk of endocrine failure (hypogonadism). Larger studies are needed to establish the correlation between testicular radiation dose and hormonal changes in this group of patients.

[Crossed central neuropathic pain syndrome after bacterial meningoencephalitis]

We report on a 48 year old female patient who acquired a bacterial meningoencephalitis as a result of a cervical myelography. Examination of the cerebrospinal fluid (CSF) revealed 309 cells per microliter and Streptococcus acidominimus was isolated as the infectious agent. Cranial MRI demonstrated disseminated lesions predominantly in the pontine and medullary brain stem as well as in thalamic nuclei. The patient developed a crossed central neuropathic pain syndrome. Neurological examination showed mechanic allodynia and hyperpathy along the left-sided extremities as well as right-sided neuropathic facial pain. On the MRI a dorsolateral medullary lesion on the right side, in the territory of the posterior inferior cerebellar artery was found. The localization of the lesion is suggestive of involvement of the spinal trigeminal tract or nucleus and the spinothalamic tract that would explain the neuropathic pain syndrome.A combination of gabapentine and amitriptyline reduced the pain markedly whereas opioids failed to provide sufficient analgesia.

Imaging of activated microglia with PET and [11C]PK 11195 in corticobasal degeneration

Positron emission tomography (PET) using [(11)C]PK 11195, a ligand for peripheral benzodiazepine receptor binding sites, offers the opportunity to image activated microglia in vivo. This tool may therefore be used to display the occurrence of microglial activation in the course of neurodegeneration. A patient with the clinical diagnosis of corticobasal degeneration (CBD) and left-sided symptoms was studied using fluorodeoxyglucose (FDG) and [(11)C]PK 11195 PET. We found a marked right hemispheric hypometabolism and asymmetric microglial activation in corresponding areas of the basal ganglia and right temporal and parietal cortex. [(11)C]PK 11195 PET suggests involvement of microglial activation in the pathogenesis of CBD.

Topography of cerebral atrophy in early Huntington's disease: a voxel based morphometric MRI study

OBJECTIVES

To analyse grey matter changes in early stages of Huntington's disease using magnetic resonance imaging (MRI) and the technique of voxel based morphometry (VBM).

METHODS

Forty four patients with a molecularly confirmed clinical diagnosis of Huntington's disease based on the presence of motor signs were included in the study. Patients were clinically rated using the Unified Huntington's Disease Rating Scale; all were in early clinical stages of the disease (that is, Shoulson stages I and II). High resolution volume rendering MRI scans (MP-RAGE) were acquired. MRI data were volumetrically analysed in comparison to an age matched normal database by VBM, using statistical parametric mapping (SPM99).

RESULTS

In Huntington's disease, robust regional decreases in grey matter density (p<0.001, corrected for multiple comparisons)-that is, atrophy-were found bilaterally in striatal areas as well as in the hypothalamus and the opercular cortex, and unilaterally in the right paracentral lobule. The topography of striatal changes corresponded to the dorso-ventral gradient of neuronal loss described in neuropathological studies. Stratification according to clinical severity showed a more widespread involvement extending into the ventral aspects of the striatum in the group of more severely affected patients.

CONCLUSIONS

The topography of cerebral volume changes associated with Huntington's disease can be mapped using VBM. It can be shown that cerebral grey matter changes co-vary with clinical severity and CAG repeat length.

Back-propagation-based neural network with a two sensor system for monitoring carbon dioxide and relative humidity

The delicate problem of independently determining the concentration of carbon dioxide and relative humidity in a gas mixture is solved by recording the signals of two quartz microbalances coated with a functionalized sensitive polymer layer. The data were analysed by back-propagation-based neural networks. We tested two different architectures, a one-stage net and a two-stage net (which consist of two network structures in series) with respect to their generalisation ability. The one-stage network calculated the concentration of carbon dioxide with an error less than 12% and that of relative humidity with an error less than 5%. The two-stage network recognised in the first step seven categories of relative humidity with a success rate of 100%, while the maximal error of carbon dioxide concentration calculated in the second level of this architecture is reduced to 9%. In addition, the generalisation ability of the two-stage network is improved compared to the one-stage network.

Positron emission tomography with [(18)F]FDG in the diagnosis of Creutzfeldt-Jakob disease (CJD)

The aim of this study was to explore the sites of metabolic changes with [(18)F]2-fluoro-2-desoxy-D-glucose (FDG) and positron emission tomography (PET) in patients with Creutzfeldt-Jakob disease and to correlate the findings with clinical symptoms. Static [(18)F]FDG-PET studies of eight patients with the diagnosis of confirmed or probable CJD were retrospectively analysed by two physicians from departments of nuclear medicine independently with a strong interrater agreement (kappa=0,98). The clinical data of the patients, based on a standardized evaluation by physicians from the German Creutzfeldt-Jakob disease surveillance study, was correlated with the PET findings. [(18)F]FDG-PET shows widespread hypometabolism in CJD. All patients had a reduction of cerebral glucose metabolism in at least one temporal or parietal region. Additionally in 7 of our own 8 cases and 3 of 4 cases from the literature the occipital lobe, the cerebellum or the basal ganglia were involved. These findings differ from typical patterns of hypometabolism in Alzheimer's disease and other neurodegenerative disorders. In two thirds of the cases the distribution was markedly asymmetric. Myoclonus was present in five out of our eight own cases. Our data suggest that myoclonus might correlate with metabolic impairment of contralateral parietal and temporal lobes. In three of four patients with visual symptoms FDG uptake was reduced in the visual cortex bilaterally. Typical hyperintensities on MRI were only found in two of the eight cases at the time of PET-studies. Our results demonstrate that [(18)F]FDG-PET appears to be a sensitive investigation in CJD and could be useful to differentiate CJD from other neurodegenerative disorders.