Fusion of vestibular and podokinesthetic information during self-turning towards instructed targets

When observers step about their vertical axis ("active turning") without vision they dispose of essentially two sources of information that can tell them by how much they have turned: the vestibular cue which reflects head rotation in space and the "podokinesthetic" cue, a compound of leg proprioceptive afferents and efference copy signals which reflects the observer's motion relative to his support. We ask how these two cues are fused in the process leading to the perception of self-displacement during active turning. To this end we compared the performance of observers in three angular navigation tasks which differed with regard to the number and type of available motion cues: (1) Passive rotation, vestibular cue ( ves) only; observers are standing on a platform which is being rotated. (2) Treadmill stepping, podokinesthetic cue ( pod) only; observers step counter to the rotating platform so as to remain stable in space. (3) Active turning, ves and pod available; observers step around on the stationary platform. In all three tasks, angular velocity varied from trial to trial (15, 30, 60 degrees /s) but was constant during trials. Perception was probed by having the observers signal when they thought to have reached a previously instructed angular displacement, either in space or relative to the platform ("target"; range 60-1080 degrees ). Performance was quantified in terms of the targeting gain (displacement reached by the observer divided by target angle) and of the random error ( E(r)), which records an observer's deviation during single trials from his average performance. Confirming previous observations, E(r) was found to be significantly smaller during active turning than during passive turning, and we now complement these observations by showing that it is also significantly smaller than during treadmill stepping. This behaviour of E(r) is compatible with the idea that ves and pod be averaged during active turning. On the other hand, the observed characteristics of the targeting gain ( G(T)) support this idea only for the case of fast rotations (60 degrees /s); at lower velocities, the gain found during active turning was clearly not the average of the G(T) values recorded in the passive and the treadmill modes. We therefore also discuss alternative scenarios as to how ves and pod could interact, among these one based on the concept of a vestibular eigenmodel. A common denominator of these scenarios is that ves assumes the role of a prerequisite for an optimal use of pod during turning on a stationary support, without itself entering the calculation of displacement perception; this perception would be based exclusively on pod. Finally, it was a consistent observation that during passive rotations cognitive mechanisms fill in for the decaying vestibular signal in the context of the present navigation task, enabling observers to achieve large displacements surprisingly well although the duration of these movements exceeds by far the conventionally cited value of the central vestibular time constant (=20 s).     

Nasogastric aspiration/lavage in patients with gastrointestinal bleeding: a review of the evidence

Introduction: The usefulness of nasogastric aspiration and nasogastric lavage in patients with gastrointestinal bleeding is controversial, as evidenced by conflicting recommendations, both among and within society guidelines.

Areas covered: Considering these controversies, we reviewed the evidence regarding the following questions: 1) Can nasogastric lavage stop or slow down the bleeding and improve subsequent endoscopic visualization? 2) Is nasogastric aspiration helpful for the localization of bleeding? 3) Can nasogastric aspiration identify high risk patients that might benefit from earlier endoscopy? 4) Is there evidence for benefit in terms of outcomes from using nasogastric aspiration? 5) Is nasogastric intubation safe in patients with possible esophageal varices? Our review was conducted according to PRISMA guidelines.

Expert commentary: Based on the available literature, nasogastric lavage or aspiration cannot be routinely recommended unless a large properly designed randomized trial (which is currently lacking) proves otherwise. It is a painful and time-consuming procedure with no demonstrated benefit for the patient in terms of outcomes. Other clinical and laboratory parameters, and risk scores, are less invasive and are effective for guiding the stratification and management of patients, while pre-endoscopic erythromycin infusion is a good if not better alternative for improving visualization of the stomach.     

Chemoprevention of liver cancer by plant polyphenols

Primary liver cancer or hepatocellular carcinoma (HCC) is one of the most frequent tumors representing the fifth commonest malignancy worldwide and the third cause of mortality from cancer. Currently, the treatments for HCC are not so effective and new strategies are needed for its fight. Chemoprevention, the use of natural or synthetic chemical agents to reverse, suppress or prevent carcinogenesis is considered an important way for confronting HCC. Many of the chemopreventive agents are phytochemicals, namely non-nutritive plant chemicals with protective or disease preventive properties. In this review, we focus on plant polyphenols, one of the most important classes of phytochemicals, their chemopreventive properties against HCC and discuss the molecular mechanisms accounting for this activity.     

Prevalence, awareness, treatment and control of hypertension in Hellas, Greece: the Hypertension Study in General Practice in Hellas (HYPERTENSHELL) national study

BACKGROUND: The Hypertension Study in General Practice in Hellas (Hypertenshell) is a cross-sectional study (much like the National Health and Nutrition Examination Study) for assessing the prevalence, level of awareness, treatment, and control of hypertension in Greece. METHODS: The study was conducted with the collaboration of physicians in 98 Health Centers across Greece. Participants were interviewed about lifestyle, and blood pressure (BP) measurements were taken on two clinical visits for verification of diagnosis and control of hypertension. Hypertension was defined as systolic BP > or =140 mm Hg or diastolic BP > or =90 mm Hg, or current treatment with antihypertensive drugs; the same threshold was used for assessing control of hypertension. RESULTS: A total of 11,950 individuals participated and data for 11,540 were analyzed, comprising 0.1% of the Greek population. The prevalence of hypertension was 31.1% (men 33.6%, women 28.4%); among elderly individuals (>65 years) the prevalence was higher (65.4%). Of the hypertensive individuals, 39.8% did not know that had hypertension, yielding an awareness of 60.2%; in addition, 12.4% were aware but not treated (men 13.1%, women 11.8%). In all, 51.2% (1838) of hypertensive subjects were treated; 67.2% (1235) were treated but not controlled (men 66.7%, women 67.7%); and 32.8% (603) were treated and controlled (men 33.3%, women 32.3%). CONCLUSIONS: The results of the Hypertenshell Study indicate that hypertension is a common risk factor for cardiovascular disease in the Greek population. Awareness, treatment, and control of hypertension are comparable to the best rates of control of hypertension given for the problem, but there is a considerable potential for further improvement in the control of this disease.     

Encephalomyelitis associated with leukemia in a child

A case of an encephalomyelitis in a child with acute lymphoblastic leukemia is reported. The patient was a 5-year-old boy who developed seizures, progressive confusion, and coma after radiation and intrathecal methotrexate therapy. Computed tomography (CT) of the brain showed bilateral hypodensities in the posterior parietal and temporal regions. At autopsy, perivascular inflammation, microglial nodules without intranuclear viral inclusions, and bilateral necrosis of the temporoparietal and hippocampal regions were seen in the brain and spinal cord. Paraneoplastic encephalomyelitis is generally recognized in adult patients with underlying malignancy but, to our knowledge, has not been reported in children with leukemia. This report should alert the clinicians to an entity that must be included in the differential diagnosis of leukemic children with progressive neurologic disorder.     

Body dysmorphic disorder due to hirsutism in a patient treated with cyclosporin

Sir, Currently administered immunosuppression schemes usually includecyclosporin. Cyclosporin has brought about a revolution in patientprognosis and in renal graft survival, but, unfortunately, ithas many side effects [1,2]. While physicians are attentiveto the more serious and life threatening of these side effects,