New ways of performing in vivo flow velocity measurements in the basilar artery

The basilar artery is the only large artery in which two flows merge, and this is reflected in the flow downstream. We report quantitative flow — velocity measurements with a phase-based MR technique, i.e. the Fourier velocity encoding method, in the basilar artery of a volunteer. To our knowledge, this has not previously been performed successfully. A comparison is made with the results of flow velocity measurements in the basilar artery with transcranial Doppler ultrasonography; the techniques agreed very well. Although Doppler ultrasonography is still most widely used, no information on the flow rate and the flow velocity distribution in the basilar artery can be provided. MR flow measurement techniques appear promising when detailed information on the flow velocity distribution and flow rate is needed.     

The TRPV4 channel: structure-function relationship and promiscuous gating behaviour

Transient receptor potential (TRP) channels provide an enormous variability of Ca(2+) influx mechanisms triggered by a wide range of stimuli. In this review, we discuss the activation properties of the Ca(2+)- and Mg(2+)-permeable TRP channel of the vanilloid subfamily TRPV4. This channel is activated by various physical and chemical stimuli, such as cell swelling, heat, phorbols and, probably, by endogenous ligands, which are able to induce Ca(2+) entry. Not much is known about the regulation of this channel. We will refer only to a mechanism of Ca(2+)-dependent inhibition of TRPV4. Possible functional roles of this channel will be correlated with its observed expression pattern. Finally, we discuss the structural determinants of TRPV4 channel function.     

Selenium Cycling Across Soil-Plant-Atmosphere Interfaces: A Critical Review

Selenium (Se) is an essential element for humans and animals, which occurs ubiquitously in the environment. It is present in trace amounts in both organic and inorganic forms in marine and freshwater systems, soils, biomass and in the atmosphere. Low Se levels in certain terrestrial environments have resulted in Se deficiency in humans, while elevated Se levels in waters and soils can be toxic and result in the death of aquatic wildlife and other animals. Human dietary Se intake is largely governed by Se concentrations in plants, which are controlled by root uptake of Se as a function of soil Se concentrations, speciation and bioavailability. In addition, plants and microorganisms can biomethylate Se, which can result in a loss of Se to the atmosphere. The mobilization of Se across soil-plant-atmosphere interfaces is thus of crucial importance for human Se status. This review gives an overview of current knowledge on Se cycling with a specific focus on soil-plant-atmosphere interfaces. Sources, speciation and mobility of Se in soils and plants will be discussed as well as Se hyperaccumulation by plants, biofortification and biomethylation. Future research on Se cycling in the environment is essential to minimize the adverse health effects associated with unsafe environmental Se levels.     

Computed tomography severity index is an early prognostic tool for acute pancreatitis

BACKGROUND: Acute pancreatitis is a severe disease with unpredictable course and outcomes. It is especially hard to identify early those patients who will have a fulminant course. In a prospective observational study, we tested the hypothesis that the CT Severity Index (CTSI), established within 48hours after admission, is prognostic for morbidity and mortality and can predict the necessity for admission to an ICU. STUDY DESIGN: From January 1994 to October 2002, all patients with the diagnosis of first time acute pancreatitis underwent spiral CT with intravenous contrast within 48hours of admission. The extent of inflammation and necrosis was assessed to define the CTSI. Patients were initially managed in an ICU in a standardized fashion. Complications and mortality were registered in a systematic manner. RESULTS: Seventy-nine patients were admitted with acute pancreatitis. The overall complication rate was 57%; mortality was 9%. In patients with a CTSI of 0 to 3, these rates were 42% and 2%, respectively; in those with CTSI of 4 to 6, 81% and 19%, respectively; and in those with CTSI of 7 to 10, 100% and 33%, respectively. Outcomes of subsequent CT scans did not alter the initial prognosis. Early CTSI correlated well with the incidence of complications, sepsis, mortality, and necessity for ICU admission. CONCLUSIONS: Acute pancreatitis is associated with marked morbidity and mortality. Initial admission to an ICU and standardized conservative treatment are justified for all patients. Early establishment of the CTSI is an excellent prognostic tool for complications and mortality. Patients with a CTSI of 0 to 3 can safely be discharged from the ICU.