Stable xenon does not increase intracranial pressure in primates with freeze-injury-induced intracranial hypertension

Stable xenon (Xe)-enhanced computed tomography is a potentially valuable tool for high resolution, three-dimensional measurement of CBF in patients. However, reports that Xe causes cerebrovascular dilation and increases intracranial pressure (ICP) have tempered enthusiasm for its use. The effects of 5 min of 33% Xe inhalation on ICP (right and left hemispheres) were studied in eight fentanyl-anesthetized Rhesus monkeys after right-sided cortical freeze injury. ICP, CBF, and physiological variables were monitored for up to 6 h postinsult. The preinjury (control) right hemispheric ICP was 8 +/- 5 mm Hg (mean +/- SD) and left hemispheric ICP was 5 +/- 2 mm Hg. Postinjury observations were classified into low (less than 15 mm Hg) and high ICP (greater than or equal to 15 mm Hg) groups. Both right and left ICP values averaged 9 +/- 3 mm Hg in the low ICP group. In the high ICP group, the right ICP was 20 +/- 4 mm Hg and left ICP was 21 +/- 6 mm Hg. ICP was unchanged by Xe inhalation under control conditions as well as in both low and high ICP groups postinjury. Postinjury, the MABP decreased 10-15 mm Hg in the low ICP group and 10-17 mm Hg in the high ICP group 2-3 min after the start of Xe inhalation (p less than 0.05). These results show that 33% Xe inhalation does not increase ICP in fentanyl-anesthetized monkeys but could decrease MABP in stressed states, presumably because of the anesthetic effects of Xe.     

Temporal neural networks for downscaling climate variability and extremes.

This paper presents an application of temporal neural networks for downscaling global climate models (GCMs) output. Because of computational constraints, GCMs are usually run at coarse grid resolution (in the order of 100s of kilometres) and as a result they are inherently unable to present local sub-grid scale features and dynamics. Consequently, outputs from these models cannot be used directly in many climate change impact studies. This research explored the issues of 'downscaling' the outputs of GCMs using a temporal neural network (TNN) approach. The method is proposed for downscaling daily precipitation and temperature series for a region in northern Quebec, Canada. The downscaling models are developed and validated using large-scale predictor variables derived from the National Center for Environmental Prediction (NCEP) reanalysis data set. The performance of the temporal neural network downscaling model is also compared to a regression-based statistical downscaling model with emphasis on their ability in reproducing the observed climate variability and extremes. The downscaling results for the base period (1961-2000) suggest that the TNN is an efficient method for downscaling both daily precipitation as well as daily maximum and minimum temperature series. Furthermore, the different model test results indicate that the TNN model mostly outperforms the statistical models for the downscaling of daily precipitation extremes and variability.     

Cerebral hemodynamic and metabolic profiles in fulminant hepatic failure: relationship to outcome.

The purpose of this retrospective study was to examine the potential role of cerebral hemodynamic and metabolic factors in the outcome of patients with fulminant hepatic failure (FHF). Based on the literature, a hypothetical model was proposed in which physiologic changes progress sequentially in five phases, as defined by intracranial pressure (ICP) and cerebral blood flow (CBF) measurements. Seventy-six cerebral physiologic profiles were obtained in 26 patients (2 to 5 studies each) within 6 days of FHF diagnosis. ICP was continuously measured by an extradural fiber optic monitor. Global CBF estimates were obtained by xenon clearance techniques. Jugular venous and peripheral artery catheters permitted calculation of cerebral arteriovenous oxygen differences (AVDO2), from which cerebral metabolic rate for oxygen (CMRO2) was derived. A depressed CMRO2 was found in all patients. There was no evidence of cerebral ischemia as indicated by elevated AVDO2s. Instead, over 65% of the patients revealed cerebral hyperemia. Eight of the 26 patients underwent orthotopic liver transplantation-all recovered neurologically, including 6 with elevated ICPs. Of the 18 patients receiving medical treatment only, all 7 with increased ICP died in contrast to 9 survivors whose ICP remained normal (P < 0.004). Hyperemia, per se, was not related to outcome, although it occurred more frequently at the time of ICP elevations. Six patients were studied during brain death. All 6 revealed malignant intracranial hypertension, preceded by hyperemia. In conclusion, the above findings are consistent with the hypothetical model proposed. Prospective longitudinal studies are recommended to determine the precise evolution of the pathophysiologic changes.     

Complications of preoperative balloon test occlusion of the internal carotid arteries: experience in 300 cases

Treatment of some tumors and aneurysms of the skull base may require internal carotid artery (ICA) sacrifice. Preoperatively to determine the dependence of the cerebral blood flow on a particular vessel, we perform a balloon test occlusion (BTO) by temporarily occluding the vessel in an awake patient. During occlusion, clinical evaluations and cerebral blood flow measurements are assessed. We have performed 300 BTOs. Eleven patients (3.7%) have had complications. Six (2%) were asymptomatic dissections. Five (1.7%) had neurologic deficits that persisted beyond the test period. Of these five, one was back to baseline in less than 24 hours, one recovered completely in a week, and one (0.33%) had a minimal but persistent dysphasia. These latter three cases are unexplained but might have resulted from unrecognized dissections or embolic events. Finally, one patient with a persistent deficit required energency surgery for reasons unrelated to the BTO and was therefore difficult to assess, and one required emergency middle cerebral artery embolectomy and repair of the dissection. The preoperative knowledge of carotid dependence in cases in which the ICA is at risk is essential, since vascular grafts or alternative surgical approaches are necessary in patients unable to tolerate carotid sacrifice. Since approximately 15 to 20% of the population falls into this category, a preoperative BTO appears justified.     

Prevalence of Disability and Associated Factors among Registered Leprosy Patients in All Africa Tb and Leprosy Rehabilitation and Training Centre (ALERT), Addis Ababa,Ethiopia

Background

Delay in leprosy diagnosis and treatment causes disabilities due to nerve damage, immunological reactions and bacillary infiltration. Leprosy disability leads not only to physical dysfunction and activity limitation but also disrupts social interaction of affected individuals by creating stigma and discrimination. This study was aimed at assessing leprosy disability status in patients registered at All African TB and Leprosy Rehabilitation and Training Centre.

Methods

Medical records of leprosy patients registered from September 11, 2010 to September 10, 2013 G.C were reviewed. Prevalence of disability calculated, bivariate and multiple logistic regressions were used to determine crude and adjusted odds ratios with 95% confidence interval.

Results

The overall prevalence of disability was found to be 65.9% from all categories of patients (40.2% Grade I and 25.7% Grade II). The Prevalence among the new category was 62.8% (39.1% Grade 1 and 23.7% Grade 2). Those ageed above 30 years, with duration of symptoms 6–12 months and above 24 months, with sensory loss, nerve damage and reversal reaction were more likely to develop disability.

Conclusion

In this study the prevalence of disability, both Grade I and II, is very high. Disability was associated with age, duration of symptom, sensory loss, signs of nerve damage and reversal reaction. These risk factors indicate the existence of delay in diagnosis and treatment of leprosy cases. Therefore, the national leprosy control program should investigate leprosy case detection and diagnosis system in the country and work on improving early case detection and prevention of disability.     

Evaluation of Gallium Citrate Formulations against a Multidrug-Resistant Strain of Klebsiella pneumoniae in a Murine Wound Model of Infection

Skin and soft tissue infections (SSTIs) are a common occurrence in health care facilities with a heightened risk for immunocompromised patients. Klebsiella pneumoniae has been increasingly implicated as the bacterial agent responsible for SSTIs, and treatment can be challenging as more strains become multidrug resistant (MDR). Therefore, new treatments are needed to counter this bacterial pathogen. Gallium complexes exhibit antimicrobial activity and are currently being evaluated as potential treatment for bacterial infections. In this study, we tested a topical formulation containing gallium citrate (GaCi) for the treatment of wounds infected with K. pneumoniae. First, the MIC against K. pneumoniae ranged from 0.125 to 2.0 μg/ml GaCi. After this in vitro efficacy was established, two topical formulations with GaCi (0.1% [wt/vol] and 0.3% [wt/vol]) were tested in a murine wound model of MDR K. pneumoniae infection. Gross pathology and histopathology revealed K. pneumoniae-infected wounds appeared to close faster with GaCi treatment and were accompanied by reduced inflammation compared to those of untreated controls. Similarly, quantitative indications of infection remediation, such as reduced weight loss and wound area, suggested that treatment improved outcomes compared to those of untreated controls. Bacterial burdens were measured 1 and 3 days following inoculation, and a 0.5 to 1.5 log reduction of CFU was observed. Lastly, upon scanning electron microscopy analysis, GaCi treatment appeared to prevent biofilm formation on dressings compared to those of untreated controls. These results suggest that with more preclinical testing, a topical application of GaCi may be a promising alternative treatment strategy for K. pneumoniae SSTI.