Mutagenicity testing of dichloromethane in short-term mammalian test systems

Several short-term mammalian test systems were used for mutagenicity testing of the organic solvent dichloromethane. The compound was negative in the forward mutation test on the HGPRT locus in Chinese hamster cells and the unscheduled DNA synthesis test in both human and hamster cells. In the test on DNA synthesis inhibition, dichloromethane caused an aspecific inhibition in both human and hamster cells, but in this test the effect did not indicate a DNA-damaging action. A weak positive effect was found in the test on sister-chromatid exchanges in hamster cells.     

Viability and Morphology of rat heart cells after freezing and thawing of the whole heart

Intact adult rat hearts were cooled in the presence of 10% DMSO according to an external cooling program which approximated the optimal external three-step cooling program for the isolated adult heart cells: 20 min at ?20 °C, 0.2 °C/min from ?20 to ?25, ?30, or ?50 °C, and rapid cooling to ?196 °C. Following rapid thawing, cells were isolated after perfusion with a 0.1% collagenase solution. Only cells which originated from the free wall of the right ventricle could be isolated, even after cooling to ?20 °C. Most cells from hearts cooled to ?196 °C did not survive. When the third cooling step was omitted and the end temperature of the second cooling step was ?30 °C, 38% of the cells excluded trypan blue, 29% were morphologically intact, and 30% showed spontaneous contractions after thawing, expressed as percentages of the control, A much lower survival was found after cooling to ?50 °C.Histological and electron microscopical study of the heart immediately after thawing revealed no differences between hearts cooled to ?20, ?30, or ?196 °C. Also no marked differences were observed between the morphological integrity after freezing and thawing of the atrium, the left and right ventricle walls, and the ventricular septum. The survival data suggest the presence of nonmorphologically detectable alterations in cells frozen to ?196 °C, compared to cells frozen to ?30 °C. The morphological investigations indicate no essential differences in resistance of atrial and ventricular cells to the freezing process.Experiments involving neonatal rat hearts cooled to ?196 °C, according to the method which gave optimal preservation of the isolated cells, revealed that after thawing cells are present from which growing and contracting cultures can be derived. It appears that cells in the neonatal rat heart are more resistant to freezing to ?196 °C than cells in the adult rat heart.     

Immunohistochemical localization of irisin in skin,eye, and thyroid and pineal glands of the crested porcupine (Hystrix cristata)

Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity.     

Competing neural responses for auditory and visual decisions

Why is it hard to divide attention between dissimilar activities, such as reading and listening to a conversation? We used functional magnetic resonance imaging (fMRI) to study interference between simple auditory and visual decisions, independently of motor competition. Overlapping activity for auditory and visual tasks performed in isolation was found in lateral prefrontal regions, middle temporal cortex and parietal cortex. When the visual stimulus occurred during the processing of the tone, its activation in prefrontal and middle temporal cortex was suppressed. Additionally, reduced activity was seen in modality-specific visual cortex. These results paralleled impaired awareness of the visual event. Even without competing motor responses, a simple auditory decision interferes with visual processing on different neural levels, including prefrontal cortex, middle temporal cortex and visual regions.     

Ultrasound imaging in an experimental model of fatty liver disease and cirrhosis in rats

Background

Atypical scrapie was first identified in Norwegian sheep in 1998 and has subsequently been identified in many countries. Retrospective studies have identified cases predating the initial identification of this form of scrapie, and epidemiological studies have indicated that it does not conform to the behaviour of an infectious disease, giving rise to the hypothesis that it represents spontaneous disease. However, atypical scrapie isolates have been shown to be infectious experimentally, through intracerebral inoculation in transgenic mice and sheep. The first successful challenge of a sheep with 'field' atypical scrapie from an homologous donor sheep was reported in 2007.

Results

This study demonstrates that atypical scrapie has distinct clinical, pathological and biochemical characteristics which are maintained on transmission and sub-passage, and which are distinct from other strains of transmissible spongiform encephalopathies in the same host genotype.

Conclusions

Atypical scrapie is consistently transmissible within AHQ homozygous sheep, and the disease phenotype is preserved on sub-passage.     

Fracture prevention in COPD patients; a clinical 5-step approach

Although osteoporosis and its related fractures are common in patients with COPD, patients at high risk of fracture are poorly identified, and consequently, undertreated. Since there are no fracture prevention guidelines available that focus on COPD patients, we developed a clinical approach to improve the identification and treatment of COPD patients at high risk of fracture. We organised a round-table discussion with 8 clinical experts in the field of COPD and fracture prevention in the Netherlands in December 2013. The clinical experts presented a review of the literature on COPD, osteoporosis and fracture prevention. Based on the Dutch fracture prevention guideline, they developed a 5-step clinical approach for fracture prevention in COPD. Thereby, they took into account both classical risk factors for fracture (low body mass index, older age, personal and family history of fracture, immobility, smoking, alcohol intake, use of glucocorticoids and increased fall risk) and COPD-specific risk factors for fracture (severe airflow obstruction, pulmonary exacerbations and oxygen therapy). Severe COPD (defined as postbronchodilator FEV₁ < 50% predicted) was added as COPD-specific risk factor to the list of classical risk factors for fracture. The 5-step clinical approach starts with case finding using clinical risk factors, followed by risk evaluation (dual energy X-ray absorptiometry and imaging of the spine), differential diagnosis, treatment and follow-up. This systematic clinical approach, which is evidence-based and easy-to-use in daily practice by pulmonologists, should contribute to optimise fracture prevention in COPD patients at high risk of fracture.     

Evidence for cadherin-11 cleavage in the synovium and partial characterization of its mechanism

IntroductionEngagement of the homotypic cell-to-cell adhesion molecule cadherin-11 on rheumatoid arthritis (RA) synovial fibroblasts with a chimeric molecule containing the cadherin-11 extracellular binding domain stimulated cytokine, chemokine, and matrix metalloproteinases (MMP) release, implicating cadherin-11 signaling in RA pathogenesis. The objective of this study was to determine if cadherin-11 extracellular domain fragments are found inside the joint and if a physiologic synovial fibroblast cleavage pathway releases those fragments.MethodsCadherin-11 cleavage fragments were detected by western blot in cell media or lysates. Cleavage was interrupted using chemical inhibitors or short-interfering RNA (siRNA) gene silencing. The amount of cadherin-11 fragments in synovial fluid was measured by western blot and ELISA.ResultsSoluble cadherin-11 extracellular fragments were detected in human synovial fluid at significantly higher levels in RA samples compared to osteoarthritis (OA) samples. A cadherin-11 N-terminal extracellular binding domain fragment was shed from synovial fibroblasts after ionomycin stimulation, followed by presenilin 1 (PSN1)-dependent regulated intramembrane proteolysis of the retained membrane-bound C-terminal fragments. In addition to ionomycin-induced calcium flux, tumor necrosis factor (TNF)-α also stimulated cleavage in both two- and three-dimensional fibroblast cultures. Although cadherin-11 extracellular domains were shed by a disintegrin and metalloproteinase (ADAM) 10 in several cell types, a novel ADAM- and metalloproteinase-independent activity mediated shedding in primary human fibroblasts.ConclusionsCadherin-11 undergoes ectodomain shedding followed by regulated intramembrane proteolysis in synovial fibroblasts, triggered by a novel sheddase that generates extracelluar cadherin-11 fragments. Cadherin-11 fragments were enriched in RA synovial fluid, suggesting they may be a marker of synovial burden and may function to modify cadherin-11 interactions between synovial fibroblasts.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0647-9) contains supplementary material, which is available to authorized users.     

Tuberculosis masquerading as malignancy: a multimodality approach to the correct diagnosis – a case report

BACKGROUND: Extrapulmonary tuberculosis is one of the great mimickers of medicine, and often masquerades as malignancy. As a result, patients may be referred to oncologists and surgeons for further evaluation and management, delaying the institution of appropriate anti-tuberculous drug therapy. CASE PRESENTATION: We present the case of a 21 year old man with tuberculous osteomyelitis, who was referred to the Bone and Soft Tissue Sarcoma Service at our institution with a provisional diagnosis of malignancy. Further investigation revealed extensive retroperitoneal abdominal and pelvic lymphadenopathy. The recognition of certain patterns on imaging, and finally the isolation of Mycobacterium tuberculosis from tissue samples obtained under image guidance, enabled the correct diagnosis to be made. CONCLUSION: This case highlights the importance of remaining cognisant of the protean manifestations of extrapulmonary tuberculosis, and illustrates the advantage of a clinically directed multi-modality imaging approach to diagnosis.