[Bitemporal scalp necrosis : a very rare manifestation of giant cell arteritis]

A 71-year-old woman developed progressive spreading of bitemporal scalp necrosis within 4 weeks accompanied by headaches, myalgia of the shoulder girdle and muscle weakness that had started a few months previously. No additional diseases were reported. The suspected temporal giant cell arteritis could be confirmed by temporal artery biopsy. Therapy with glucocorticoids led to a rapid resolution of clinical symptoms and was tapered over 18 months. Recovery of the scalp necrosis emerged following second intention healing and split-skin transplantation of necrotic areas after successful wound conditioning. The case study demonstrates a rare and serious complication of temporal arteritis which is often accompanied by a poor prognosis.

Substance use and sexual risk behaviour among HIV-positive men who have sex with men in specialized out-patient clinics

OBJECTIVES

Unprotected sexual intercourse between men who have sex with men (MSM) is the most common route of HIV infection in Germany. Approximately 70% of newly infected people are MSM. Substance use is a determinant of sexual risk behaviour in the general population, but also in the MSM subpopulation. There are only a few studies, from the USA, on the correlation between substance use and sexual risk behaviour in HIV-infected MSM in specialized care.

METHODS

In a German sample of 445 HIV-infected MSM treated in specialized out-patient clinics, the influence of substance use on sexual risk behaviour was investigated. Information was obtained from subjects using self-report questionnaires and a structured interview.

RESULTS

Recreational drug use was common. The prevalences of cannabis addiction (4.5%), harmful use of cannabis (4.3%) and harmful use of dissociative anaesthetics (0.4%) were higher than in the general German male population. A substantial proportion of patients reported unprotected insertive (32.9%) and receptive (34.6%) anal intercourse during the last 12 months. Use of cannabis, amyl nitrite, dissociative anaesthetics, cocaine, amphetamines and erectile dysfunction medication was significantly correlated with unprotected sexual contacts. Substance use in the context of sexual activity significantly increased sexual risk behaviour.

CONCLUSIONS

Substance use, especially in the context of sexual activity, should be taken into account when developing new prevention and intervention programmes aimed at reducing sexual risk behaviour in HIV-infected MSM currently in specialized care.

Downregulation of PRDX1 by promoter hypermethylation is frequent in 1p/19q-deleted oligodendroglial tumours and increases radio- and chemosensitivity of Hs683 glioma cells in vitro

Deletions of chromosomal arms 1p and 19q are frequent in oligodendroglial tumours and linked to radio- and chemotherapy response as well as longer survival. The molecular mechanisms underlying this clinically important association are as yet unknown. Here, we studied the peroxiredoxin 1 (PRDX1) gene at 1p34.1 for promoter methylation and expression in primary gliomas and investigated its role in radio- and chemosensitivity of glioma cells in vitro. In total, we screened primary glioma tissues from 93 patients for methylation of the 5'-CpG island of PRDX1 by sodium bisulfite sequencing. PRDX1 mRNA and protein expression levels were determined in subsets of the tumours by quantitative PCR and western blot analysis, respectively. PRDX1 hypermethylation and reduced expression were frequently detected in oligodendroglial tumours and secondary glioblastomas, but not in primary glioblastomas. In oligodendroglial tumours, both PRDX1 hypermethylation and reduced mRNA expression were significantly associated with 1p/19q-deletion. Stable knockdown of PRDX1 by lentiviral transduction of short-hairpin (sh)RNA constructs significantly increased apoptosis and reduced cell viability of Hs683 glioma cells exposed to ionizing irradiation or temozolomide in vitro. Taken together, our findings indicate that epigenetic silencing of PRDX1 is frequent in 1p/19q-deleted oligodendroglial tumours and likely contributes to radio- and chemosensitivity of these tumours.

Microparticles in a collisional Rf plasma sheath under hypergravity conditions as probes for the electric field strength and the particle charge

We used microparticles under hypergravity conditions, induced by a centrifuge, in order to measure nonintrusively and spatially resolved the electric field strength as well as the particle charge in the collisional rf plasma sheath. The measured electric field strengths demonstrate good agreement with the literature, while the particle charge shows decreasing values towards the electrode. We demonstrate that it is indeed possible to measure these important quantities without changing or disturbing the plasma.

Endohelminth parasites from salmonids in intensive culture from southern Chile

A total of 228 salmonids (90 Oncorhynchus mykiss, 48 Oncorhynchus kisutch, and 90 Salmo salar) from 8 intensive aquaculture centers in the south of Chile were examined for endohelminths parasites between December 2008 and May 2009. The body cavities of 2 O. mykiss were infected by Diphyllobothrium sp. plerocercoids (prevalence: 6.7%, mean intensity: 1.0, mean abundance: 0.07) from the Lake Tarahuin hatchery on the south of Chiloé Island. Also, tetraphyllidean plerocercoids (prevalence: 3.3%, mean intensity: 1, mean abundance: 0.03) and fourth-stage larvae of Hysterothylacium aduncum (prevalence: 6.7%, mean intensity: 1, mean abundance 0.07) were observed in O. kisutch from a marine hatchery in Chiloé. The occurrences of Diphyllobothrium sp. in a lake and a tetraphyllidean plerocercoid from marine cultured salmonid in Chiloé are reported for first time. No muscular infection by helminths was recorded in the fish examined.

Spatial input for temporal navigation in scientific visualizations

Scientific-visualization tools can make time-varying simulations easier to understand. The growing efficiency of today's high-performance computers enables simulation of physical phenomena with a high temporal resolution. Consequently, visualization systems require efficient navigation in the temporal dimension. This 3D user interface employs direct-manipulation metaphors for temporal navigation in scientific visualizations. By interacting with objects using their 3D trajectory, users can navigate in time by specifying spatial inputs.

Depth perception in virtual reality: distance estimations in peri- and extrapersonal space

The present study investigated depth perception in virtual environments. Twenty-three participants verbally estimated ten distances between 40 cm and 500 cm in three different virtual environments in two conditions: (1) only one target was presented or (2) ten targets were presented at the same time. Additionally, the presence of a metric aid was varied. A questionnaire assessed subjective ratings about physical complaints (e.g., headache), the experience in the virtual world (e.g., presence), and the experiment itself (self-evaluation of the estimations). Results show that participants underestimate the virtual distances but are able to perceive the distances in the right metric order even when only very simple virtual environments are presented. Furthermore, interindividual differences and intraindividual stabilities can be found among participants, and neither the three different virtual environments nor the metric aid improved depth estimations. Estimation performance is better in peripersonal than in extrapersonal space. In contrast, subjective ratings provide a preferred space: a closed room with visible floor, ceiling, and walls.