Cooperative assembly and dynamic disassembly of MDA5 filaments for viral dsRNA recognition

MDA5, an RIG-I-like helicase, is a conserved cytoplasmic viral RNA sensor, which recognizes dsRNA from a wide-range of viruses in a length-dependent manner. It has been proposed that MDA5 forms higher-order structures upon viral dsRNA recognition or during antiviral signaling, however the organization and nature of this proposed oligomeric state is unknown. We report here that MDA5 cooperatively assembles into a filamentous oligomer composed of a repeating segmental arrangement of MDA5 dimers along the length of dsRNA. Binding of MDA5 to dsRNA stimulates its ATP hydrolysis activity with little coordination between neighboring molecules within a filament. Individual ATP hydrolysis in turn renders an intrinsic kinetic instability to the MDA5 filament, triggering dissociation of MDA5 from dsRNA at a rate inversely proportional to the filament length. These results suggest a previously unrecognized role of ATP hydrolysis in control of filament assembly and disassembly processes, thereby autoregulating the interaction of MDA5 with dsRNA, and provides a potential basis for dsRNA length-dependent antiviral signaling.     

Prevalence and characteristics of patients with risky alcohol consumption presenting to emergency departments in rural Australia

Objective: This study measures the prevalence of problematic alcohol consumption in patients of EDs in rural areas of Australia, relative to the general population in the same rural communities. It also identifies the characteristics associated with risky drinking in rural ED patients. Methods: Surveys containing the Alcohol Use Disorders Identification Test (AUDIT) and questions corresponding to the 2001 Australian Alcohol Guidelines were completed by 1056 patients presenting to five EDs in rural areas of New South Wales, and 756 residents of the same five communities. Results: Relative to the general community, ED patients were statistically significantly more likely to engage in risky alcohol consumption according to the AUDIT (39% vs 20%), alcohol consumption posing a high risk of short‐term harm (26% vs 18%) and alcohol consumption posing a high risk of long‐term harm (7% vs 3%). Although being aged under 40 years of age, being unmarried, not completing school and being assigned less urgent triage categories were associated with risky alcohol use among ED patients, rates of risky consumption were high across all patient subgroups. Conclusions: Risky drinking, across a number of measures, is overrepresented in patients of rural Australian EDs relative to the general community, and this type of consumption is not limited to certain subgroups of patients. There is a need for interventions that address both heavy single occasion drinking and excessive regular consumption in patients of rural Australian EDs, with universal interventions recommended rather than targeted programmes.     

Influence of a Regional Centralised Upper Gastrointestinal Cancer Service Model on Patient Safety,Quality of Care and Survival

AimsThe aim of this study was to determine outcomes of a reconfigured centralised upper gastrointestinal (UGI) cancer service model, allied to an enhanced recovery programme, when compared with historical controls in a UK cancer network.Materials and methodsDetails of 606 consecutive patients diagnosed with UGI cancer were collected prospectively and outcomes before (n = 251) and after (n = 355) centralisation compared. Primary outcome measures were rates of curative treatment intent, operative morbidity, length of hospital stay and survival.ResultsThe rate of curative treatment intent increased from 21 to 36% after centralisation (P < 0.0001). Operative morbidity (mortality) and length of hospital stay before and after centralisation were 40% (2.5%) and 16 days, compared with 45% (2.4%) and 13 days, respectively (P = 0.024). The median and 1 year survival (all patients) improved from 8.7 months and 39.0% to 10.8 months and 46.8%, respectively, after centralisation (P = 0.032). On multivariate analysis, age (hazard ratio 1.894, 95% confidence interval 0.743–4.781, P < 0.0001), centralisation (hazard ratio 0.809, 95% confidence interval 0.668–0.979, P = 0.03) and overall radiological TNM stage (hazard ratio 3.905, 95% confidence interval 1.413–11.270, P < 0.0001) were independently associated with survival.ConclusionThese outcomes confirm the patient safety, quality of care and survival improvements achievable by compliance with National Health Service Improving Outcomes Guidance.     

Spontaneous Cerebellar Primitive Neuroectodermal Tumor in a Juvenile Cynomolgus Monkey (Macaca fascicularis)

A neoplastic mass compressing the left cerebellar hemisphere and hindbrain was observed at trimming in a 3½-year-old male cynomolgus monkey from a control dose group. Microscopically, the neoplastic mass was nonencapsulated, invasive, and showed two morphological patterns. The predominant area consisted of densely packed undifferentiated, polygonal to spindle cells arranged in vague sheets supported by a scant fibrovascular stroma. The other area was less cellular and composed of round neoplastic cells separated by eosinophilic fibrillar material. Immunohistochemical staining for vimentin, synaptophysin, glial fibrillary acidic protein, neuron-specific enolase, neurofilament, and S-100 confirmed the presence of primitive undifferentiated neuroectodermal cells and some cells with neuronal or glial differentiation. On the basis of histopathology and immunohistochemical findings, a diagnosis of cerebellar primitive neuroectodermal tumor with neuronal and glial differentiation was made. Primitive neuroectodermal tumors are rare in animals including nonhuman primates; this is the first published report in this species.     

Isolation of human multipotent neural progenitors from adult filum terminale

Stem cells have been isolated from several CNS regions, including the spinal cord. However, the terminal end of the spinal cord, filum terminale, has been referred to as a fibrovascular tag without neurogenic potential and of no clinical significance. Recently, we were fortunate to acquire some samples of this tissue. We show for the first time that progenitor cells exhibiting the hallmarks of stem cells can be isolated from adult human filum terminale (FTNPs). More specifically, FTNPs self-renew and proliferate to form neurospheres, and exhibit tripotent differentiation into neurons, astrocytes, and oligodendrocytes. Equally important, FTNPs develop the electrophysiological profile of neurons and glia. Whole-cell patch-clamp recordings show beta-III-tubulin(+) neurons exhibiting overshooting action potentials, displaying both the fast inactivating TTX-sensitive sodium current as well as 4-AP and TEA sensitive potassium currents. To assess potency in vivo, FTNPs were transplanted into the posterior periventricular region of control or ischemic rat brains. Despite a vigorous immune response against the xenograft, FTNPs survived and were found not only in the graft area but had also migrated to the lesioned CA1 region. Notwithstanding the immune response, FTNPs differentiated into astrocytes, but no neuronal differentiation was observed in the transplant milieu tested. However, neuronal differentiation in vivo cannot be ruled out and assessment of the conditions necessary to promote neurogenesis in vivo requires more research. Significantly, no tumor formation or aberrant cell morphology was seen in or adjacent to the graft area. Thus, filum terminale provides a novel source of adult human neural progenitor cells that develop into functional neurons with possible clinical applications.     

Mathematical modeling of glucose supply toward successful in vitro maturation of Mammalian oocytes

In vitro maturation-whereby an oocyte is harvested from an ovary just before full maturation, matured in the laboratory, fertilized, and then transplanted back to the uterus-has important benefits over, but is significantly less successful than, traditional in vitro fertilization. Inadequate in vitro nutrient environments are believed to be a prime reason for the low success, but understanding of the in vivo environment, which needs to be better replicated in the laboratory, is still lacking. We here consider mathematical modeling as an aid to increasing that understanding. A general mathematical model suitable for examining the in vivo concentrations of a nutrient in the cumulus-oocyte complex (COC) is presented. We then tailor the model to consider glucose concentration. Experimental data are used to obtain information on glucose uptake in the COC for use in the model. Finally, we solve the model to estimate glucose concentration in the COC. With the information currently available, the model indicates a significant reduction in glucose concentration from the follicular fluid across the cumulus matrix to the oocyte.