Developing a spatial-statistical model and map of historical malaria prevalence in Botswana using a staged variable selection procedure

Background  

Several malaria risk maps have been developed in recent years, many from the prevalence of infection data collated by the MARA (Mapping Malaria Risk in Africa) project, and using various environmental data sets as predictors. Variable selection is a major obstacle due to analytical problems caused by over-fitting, confounding and non-independence in the data. Testing and comparing every combination of explanatory variables in a Bayesian spatial framework remains unfeasible for most researchers. The aim of this study was to develop a malaria risk map using a systematic and practicable variable selection process for spatial analysis and mapping of historical malaria risk in Botswana.     

Contractile properties and fatigue of quadriceps muscles in multiple sclerosis

Functional characteristics of electrically stimulated quadriceps muscles of patients with multiple sclerosis (MS) were determined to investigate whether adaptations in muscle properties contribute to the higher fatigability of these patients. The estimated maximal isometric force generating capacity of MS patients was only 11.2% (P < 0.05) lower than control subjects. However, the patients were only able to voluntarily exert 75 +/- 22% (n = 12) of their maximal capacity, against 94 +/- 6% (n = 7) for the control subjects. There were no differences in muscle speed, suggesting that muscle fiber distribution was not different in the MS patients due to reduced muscle usage. During a series of repeated contractions, greater decrements occurred in isometric force and in maximal rate of force rise in the MS patients (by 31.3 +/- 10.3% and 50.1 +/- 10.0%, respectively; n = 13) than control subjects (23.8 +/- 6.6% and 39.0 +/- 8.1%, n = 15), suggesting a lower oxidative capacity. The results indicate that increasing the mass of their muscles by training may help to reduce the excessive muscle fatigue of MS patients.     

False negative biliary scintigraphy in gangrenous cholecystitis

Gangrenous cholecystitis is a serious complication of acute cholecystitis and is associated with increased morbidity and mortality rates. We report a case in which the diagnosis was suggested by ultrasound, but cholecystectomy delayed due to atypical clinical presentation and a false negative radionuclide biliary scan.     

Computed tomography fluoroscopy‐guided chemical lumbar sympathectomy: Simple,safe and effective

Demographic, clinical and laboratory data were retrospectively collected from records of 146 cases of CT fluoroscopy‐guided chemical lumbar sympathectomy for the palliation of inoperable peripheral vascular disease (PVD) between January 1997 and August 1999. Of these, 16% had claudication, 39% had rest pain and 44% had ischaemic ulcers or gangrene. Seventy‐three percent of elective cases were outpatients. At 3 months, 27 cases were lost to follow up, leaving 119 cases. Within 3 months, improvement, defined as doubling of the walking distance, cessation of rest pain or healing of ulcers, occurred in 30.3% of cases. No change was observed in 45.4% of cases and 24.3% of cases deteriorated. Patients with ulcers or gangrene had significantly poorer results than those without any ischaemic lesions, as only 19% versus 39% of patients improved (P < 0.05). The presence of hypertension, diabetes mellitus, hyperlipidaemia and smoking had no value in predicting clinical outcome (P > 0.05). There were no major complications noted. CT fluoroscopy‐guided chemical lumbar sympathectomy is safe and effective, with a complication rate of less than 1%, and efficacy of at least 30% measured within 3 months. It is a simple and minimally invasive procedure, easily performed on an outpatient basis. CT fluoroscopy‐guided chemical lumbar sympathectomy should be considered for all patients in the early stages of inoperable PVD.     

Adenoviral vector transfection into the pulmonary epithelium after cecal ligation and puncture in rats

BACKGROUND: Adenoviral-targeted gene delivery to respiratory epithelium can augment production of specific proteins. Therefore, it may be valuable in treating the acute respiratory distress syndrome. The authors tested the hypothesis that adenoviral vector uptake after cecal ligation and double puncture in rats, an animal model of the acute respiratory distress syndrome, is higher than that observed in controls that did not undergo operation ("nonoperated") or those that underwent a sham operation ("sham-operated"). METHODS: Adenoviruses expressing green fluorescent protein or Lac-Z were delivered into the lungs of anesthetized rats via tracheal catheter. Animals were killed 24 or 48 h later. Histopathology and green fluorescent protein expression were examined using light of fluorescence microscopy. Cellular localization of Lac-Z was determined with electron microscopy or semithin sectioning. Viral receptor density and localization were determined using imunoblotting and immunohistochemistry. RESULTS: After cecal ligation and double puncture, rats were hypoxic and tachypneic. Alveoli were segmentally consolidated, contained proteinaceous debris and neutrophils, and had thickened septa. Administration of adenoviruses to rats that were sham-operated or underwent cecal ligation and double puncture resulted in high levels of marker protein expression in cells lining alveoli. Use of 3 x 10(11) plaque-forming units instead of 3 x 10(12) plaque-forming units resulted in similar levels of green fluorescent protein expression with negligible viral-mediated lymphocytic infiltration. Semithin section and electron microscopy revealed expression primarily localized to type II alveolar cells. Abundance of alpha(v)beta3 integrins and human coxsackie-adenovirus receptor (receptors that modulate viral attachment and internalization) was increased after cecal ligation and double puncture, predominantly in type II pneumocytes. CONCLUSIONS: Cecal ligation and double puncture induces histologic and functional changes consistent with the acute respiratory distress syndrome, increases surface expression of viral receptors, and enhances adenoviral-mediated gene transfer.     

The relationship between hippocampal EEG theta activity and locomotor behaviour in freely moving rats: effects of vigabatrin

The relationship between hippocampal electroencephalogram (EEG) theta activity and locomotor speed in both spontaneous and forced walking conditions was studied in rats after vigabatrin injection (500 mg/kg i.p.). Vigabatrin increased the percentage of time that rats spent being immobile. During spontaneous walking in the open field, the speed of locomotion was increased by vigabatrin, while theta peak frequency was decreased. Vigabatrin also reduced the theta peak frequency during forced (speed controlled) walking. There was only a weak positive correlation (r=0.22) between theta peak frequency and locomotor speed for the saline condition. Furthermore, vigabatrin abolishes the weak relationship between speed of locomotion and theta peak frequency. Vigabatrin and saline did not differ in the slope of the regression line, but showed different offset points at the theta peak frequency axis. Thus, other factors than speed of locomotion seem to be involved in determination of the theta peak frequency.