[Handling of laundry and garbage in nursing homes. A survey in 22 homes]. / Umgang mit Wäsche und Abfall in Alten- und Pflegeheimen. Eine Erfassung in 22 Heimen.

Management of infectious diseases in nursing homes is as important as it is in hospitals. Therefore, a standardized questionnaire was used for the detailed assessment of the handling of laundry and garbage with a special focus on methicillin-resistant staphylococcus aureus (MRSA) in 22 nursing homes in Germany. The study focused on the prevention of occupational diseases in the nursing home staff. Despite a few isolated problems, the situation of MRSA-positive patients was not as alarming as expected: guidelines for MRSA as published by KRINKO were often followed by the healthcare workers. However, general problems with managing garbage and laundry were identified. Many nursing homes lacked protective clothing and a sufficient garbage management plan. In addition, the handling of laundry was a problem in that the clothing of the patients and the working clothes of the staff were often washed at home rather than in accredited laundries. Thus, the awareness for hygienic problems needs to be raised, e.g., by expanding hygienic control for the nursing homes.

Time-lapse imaging of in vitro myogenesis using atomic force microscopy.

Myoblast therapy relies on the integration of skeletal muscle stem cells into distinct muscular compartments for the prevention of clinical conditions such as heart failure, or bladder dysfunction. Understanding the fundamentals of myogenesis is hence crucial for the success of these potential medical therapies. In this report, we followed the rearrangement of the surface membrane structure and the actin cytoskeletal organization in C2C12 myoblasts at different stages of myogenesis using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). AFM imaging of living myoblasts undergoing fusion unveiled that within minutes of making cell-cell contact, membrane tubules appear that unite the myoblasts and increase in girth as fusion proceeds. CLSM identified these membrane tubules as built on scaffolds of actin filaments that nucleate at points of contact between fusing myoblasts. In contrast, similarly behaving membrane tubules are absent during cytokinesis. The results from our study in combination with recent findings in literature further expand the understanding of the biochemical and membrane structural rearrangements involved in the two fundamental cellular processes of division and fusion.

[Waste management in hospitals. Current situation in the state of North Rhine-Westphalia]. / Abfallentsorgung in Krankenhäusern. Darstellung der Ist-Situation in Nordrhein-Westfalen.

In 20 hospitals in North Rhine-Westphalia in-plant handling wastes and the delivery of the waste to the disposer were examined. Deficits were seen regarding risk assessment and operating instructions, support by company doctors, personal protection equipment, and break areas for the waste collecting personnel. Also the qualification of the waste management officer and his/her time contingent, correct declaration of the wastes, the training of the waste collecting personnel, the cleaning of multi-use containers and transportation vehicles, storage of the wastes at the collecting points, and the use of sharp collecting boxes were to be partly criticized. Consequences and recommendations are given, concerning the company's obligations (e.g., provide risk assessment, operating instructions), waste management officer (e.g., qualification, enough time contingent, regular inspections), waste collecting personnel (e.g., training courses), industrial safety (e.g., protection equipment, break area wash places), company doctors, transportation vehicles in the house (e.g., regular cleaning), one-way collectors (e.g., labelling at the site of the collection), multi-use collectors (e.g., cleaning), and compressing containers (e.g., larger maintenance openings).

Use of brain grafts to study the pathogenesis of prion diseases.

For the study of prion neurotoxicity, we used neural-grafting techniques: mice devoid of the normal host prion protein (Prnp% mice) received a neural graft and were intracerebrally infected with mouse prions. The growth and differentiation properties of neural grafts were defined. Growth of embryonic neuroectodermal tissue was optimal at gestational days 12.5-13.5. The blood-brain barrier is reconstituted after 7 weeks in most animals. Scrapie-infected PrPC-expressing grafts develop a severe spongiform encephalopathy and contain proteinase-resistant protein and infectivity. Infected grafts deliver high amounts of prions to the host brain without eliciting disease. Infected grafts show a progressive disruption of the blood-brain barrier. Following intraocular prion inoculation of a transplanted Prnp% mouse, prions do not reach the intracerebral graft, indicating that PrP expression is required for propagation along the optic tract.

[Is crazy cow disease the cause of the new variant of Creutzfeldt-Jakob syndrome?]. / Forårsager kogalskab den nye variant af Creutzfeldt-Jakobs sygdom?

In 1986, veterinary pathologists discovered spongiform encephalopathy in the brains of two cows in the UK. These two cases turned out to be the beginning of epidemic bovine spongiform encephalopathy (BSE), which culminated in 1992 with more than 3000 cases monthly. In 1996, the British government announced that a distinct variant of CJD (vCJD) had occurred in ten young people in the UK. The cases were notified within the past 1 1/2 years. A link to BSE seemed likely. Transmission studies of the two diseases have demonstrated similar properties such as incubation time, neuropathology and glycoform profile of the pathologically altered prionprotein. In effect, vCJD is very likely to represent human BSE. Epidemiological data suggest that BSE transmission to humans may have occurred only in a limited number of cases. Future studies will have to confirm this. So far, no increase in the incidence of vCJD has been noticed.

A phase II/III trial of bitopertin monotherapy compared with placebo in patients with an acute exacerbation of schizophrenia - results from the CandleLyte study.

Bitopertin is a glycine reuptake inhibitor postulated to improve N-methyl-d-aspartate receptor hypofunction by increasing synaptic glycine concentrations. This randomised, double-blind, placebo- and active-controlled phase II/III trial evaluated the efficacy and safety of bitopertin monotherapy over 4 weeks in patients with acute exacerbation of schizophrenia. Of 301 patients randomised, 299 received placebo (n=80), bitopertin 10mg (n=80) or 30mg (n=77), or olanzapine 15mg (n=62). The primary endpoint, change from baseline in mean Positive and Negative Syndrome Scale (PANSS) total score, showed non-statistically significant improvements with bitopertin 30mg and olanzapine vs. placebo: bitopertin 10mg (-11.7; standard error [SE], 1.89; p=0.945), bitopertin 30mg (-15.3; SE, 1.87; p=0.211), olanzapine (-14.9; SE, 2.13; p=0.295) and placebo (-11.9; SE, 1.90). The PANSS positive subscale score, a secondary endpoint, also showed improvement with bitopertin 30mg (p=0.030) whereas a trend was observed with olanzapine (p=0.072) vs. placebo. Although not statistically significant, bitopertin 30mg and olanzapine reduced overall illness severity (Clinical Global Impression-Severity Scale; p=0.098 and p=0.126, respectively). More patients receiving bitopertin 30mg (51.3%) or olanzapine (52.5%) than placebo (32.9%) were ready for hospital discharge at Week 4 (bitopertin, p=0.014; olanzapine, p=0.024). In summary, this study failed due to lack of statistical separation of either bitopertin or olanzapine (active control) from placebo on the primary endpoint. Of interest, improved positive symptoms and readiness for hospital discharge were associated with both bitopertin and olanzapine treatment. Bitopertin was safe and well tolerated in this study.

From particle self-assembly to functionalized sub-micron protein patterns.

Biologically relevant nanopatterns are useful platforms to address fundamental questions, for example, regarding protein-protein and cell-protein interactions. For the creation of nanopatterns, complex and expensive instrumentation is often needed. We present a simple but versatile patterning method using a combination of particle and subsequent molecular self-assembly to produce ordered structures in the micron and sub-micron range. Polystyrene particles were, in a first step, assembled via dip-coating or dried in a drying cell. Silicon wafers and glass slides coated with SiO(2) and a top layer of 11 nm of TiO(2) were used as substrates. Large hexagonally ordered particle monolayers were formed with high reproducibility. These were subsequently shrunk in a controlled manner by exposure to a O(2)/N(2) plasma and subsequently used as etching masks to transfer the particle pattern onto the substrate, creating TiO(2) features in an SiO(2) background. After removing the mask the oxide contrast was translated in three simple dip-and-rinse steps into a biochemical contrast of protein-coated features in an inert background. In short, alkane phosphates were first selectively adsorbed to the TiO(2) features. Then the SiO(2) background was backfilled using poly(L-lysine)-graft-poly(ethylene glycol) and finally streptavidin was adsorbed to the hydrophobic alkane phosphate SAMs, allowing subsequent binding and hybridization of biotinylated DNA.

Sleep-wake disturbances in sporadic Creutzfeldt-Jakob disease.

BACKGROUND: The prevalence and characteristics of sleep-wake disturbances in sporadic Creutzfeldt-Jakob disease (sCJD) are poorly understood. METHODS: Seven consecutive patients with definite sCJD underwent a systematic assessment of sleep-wake disturbances, including clinical history, video-polysomnography, and actigraphy. Extent and distribution of neurodegeneration was estimated by brain autopsy in six patients. Western blot analyses enabling classification and quantification of the protease-resistant isoform of the prion protein, PrPSc, in thalamus and occipital cortex was available in four patients. RESULTS: Sleep-wake symptoms were observed in all patients, and were prominent in four of them. All patients had severe sleep EEG abnormalities with loss of sleep spindles, very low sleep efficiency, and virtual absence of REM sleep. The correlation between different methods to assess sleep-wake functions (history, polysomnography, actigraphy, videography) was generally poor. Brain autopsy revealed prominent changes in cortical areas, but only mild changes in the thalamus. No mutation of the PRNP gene was found. CONCLUSIONS: This study demonstrates in sporadic Creutzfeldt-Jakob disease, first, the existence of sleep-wake disturbances similar to those reported in fatal familial insomnia in the absence of prominent and isolated thalamic neuronal loss, and second, the need of a multimodal approach for the unambiguous assessment of sleep-wake functions in these patients.

Spinal MRI in vacuolar myelopathy, and correlation with histopathological findings.

We correlated MRI features with histopathological findings in an HIV-positive patient with vacuolar myelopathy. On MRI symmetrical nonenhancing high-signal areas in the posterior columns on T2-weighted images result from extensive vacuolation visible on histological sections.

Modulation of signal transduction through the cellular prion protein is linked to its incorporation in lipid rafts.

Because expressed at a significant level at the membrane of human T cells, we made the hypothesis that the cellular prion protein (PrPc) could behave as a receptor, and be responsible for signal transduction. PrPc engagement by specific antibodies was observed to induce an increase in cytosolic calcium concentration and led to enhanced activity of Src protein tyrosine kinases. Antibodies to CD4 and CD59 did not influence calcium fluxes or signaling. The effect was maximal after the formation of a network involving avidin and biotinylated antibody to PrPc and was inhibited after raft disruption. PrPc localization was not restricted to rafts in resting cells but engagement was a prerequisite for signaling induction, with concomitant PrPc recruitment into rafts. These results suggest a role for PrPc in signaling pathways, and show that lateral redistribution of the protein into rafts is important for subsequent signal transduction.

Normal host prion protein (PrPC) is required for scrapie spread within the central nervous system.

Mice devoid of PrPC (Prnp%) are resistant to scrapie and do not allow propagation of the infectious agent (prion). PrPC-expressing neuroectodermal tissue grafted into Prnp% brains but not the surrounding tissue consistently exhibits scrapie-specific pathology and allows prion replication after inoculation. Scrapie prions administered intraocularly into wild-type mice spread efficiently to the central nervous system within 16 weeks. To determine whether PrPC is required for scrapie spread, we inoculated prions intraocularly into Prnp% mice containing a PrP-overexpressing neurograft. Neither encephalopathy nor protease-resistant PrP (PrPSc) were detected in the grafts for up to 66 weeks. Because grafted PrP-expressing cells elicited an immune response that might have interfered with prion spread, we generated Prnp% mice immunotolerant to PrP and engrafted them with PrP-producing neuroectodermal tissue. Again, intraocular inoculation did not lead to disease in the PrP-producing graft. These results demonstrate that PrP is necessary for prion spread along neural pathways.

[Significance of prion protein in transmission of prions and in pathogenesis of spongiform encephalopathies]. / Die Bedeutung des Prion-Proteins in der Ausbreitung von Prionen und in der Pathogenese der spongiformen Enzephalopathien.

Prion disease or transmissible spongiform encephalopathies are caused by novel pathogens termed prions. Unlike classical infectious agents such as viruses or bacteria, prions lack an independent genome and consist largely if not entirely of an abnormal form of the host-encoded prion protein. How prions multiply is not known. A wealth of experimental evidence supports an essential role for the host-encoded prion protein in susceptibility and pathogenesis of prion diseases and in the propagation and spread of prions. In addition, B lymphocytes have been found to play a crucial role in the neuroinvasiveness of prions.

Tracking prions: the neurografting approach.

The physical nature of the agent that causes transmissible spongiform encephalopathies (the 'prion'), is the subject of passionate controversy. Investigation of it has benefited tremendously from the use of transgenic and knockout technologies. However, prion diseases present several other enigmas, including the mechanism of brain damage and how the affinity of the agent for the central nervous system is controlled. Here we show that such questions can be effectively addressed in transgenic and knockout systems, and that pathogenesis may be clarified even before we can be certain about the nature of the infectious agent. Availability of mice overexpressing the Prnp gene (which encodes the normal prion protein) and Prnp knockout mice allows for selective reconstitution experiments aimed at expressing PrP in specific portions of the brain or in selected populations of hemato- and lymphopoietic origin. We summarize how such studies can offer insights into how prions administered to peripheral sites can gain access to central nervous tissue, and into the molecular requirements for spongiform brain damage.

PrP-expressing tissue required for transfer of scrapie infectivity from spleen to brain.

Much available evidence points to a pathological isoform of the prion protein PrP being the infectious agent that causes transmissible spongiform encephalopathies, but the mechanisms controlling the neurotropism of prions are still unclear. We have previously shown that mice that do not express PrP (Prnp[o/o] mice) are resistant to infection by prions, and that if a Prnp(+/+) neurograft is introduced into such animals and these are infected intracerebrally with scrapie, the graft but not the surrounding tissue shows scrapie pathology. Here we show that PrP-expressing neurografts in Prnp(o/o) mice do not develop scrapie histopathology after intraperitoneal or intravenous inoculation with scrapie prions. Prion titres were undetectable in spleens of inoculated Prnp(o/o) mice, but were restored to wild-type levels upon reconstitution of the host lymphohaemopoietic system with PrP-expressing cells. Surprisingly, however, i.p. or i.v. inoculation failed to produce scrapie pathology in the neurografts of 27 out of 28 reconstituted animals, in contrast to intracerebral inoculation. We conclude that transfer of infectivity from the spleen to the central nervous system is crucially dependent on the expression of PrP in a tissue compartment that cannot be reconstituted by bone marrow transfer. Thus the requirement for the normal isoform of PrP in peripheral tissues represents a bottleneck for the spread of prions from peripheral sites to the central nervous system.

Expression of amino-terminally truncated PrP in the mouse leading to ataxia and specific cerebellar lesions.

The physiological role of prion protein (PrP) remains unknown. Mice devoid of PrP develop normally but are resistant to scrapie; introduction of a PrP transgene restores susceptibility to the disease. To identify the regions of PrP necessary for this activity, we prepared PrP knockout mice expressing PrPs with amino-proximal deletions. Surprisingly, PrP lacking residues 32-121 or 32-134, but not with shorter deletions, caused severe ataxia and neuronal death limited to the granular layer of the cerebellum as early as 1-3 months after birth. The defect was completely abolished by introducing one copy of a wild-type PrP gene. We speculate that these truncated PrPs may be nonfunctional and compete with some other molecule with a PrP-like function for a common ligand.