Microsomal warfarin binding and vitamin K 2,3-epoxide reductase

Rat liver microsomal 4-hydroxycoumarin binding was studied by assaying specific [14C]warfarin binding. Microsomes of warfarin-sensitive rats contained about 40 pmole of specific binding sites per mg of microsomal protein. There was no difference for R- or S-[14C]warfarin. Neither was there any difference between the enantiomers of acenocoumarol and phenprocoumon to prevent the in vitro racemic [14C]warfarin binding. Pretreatment of the microsomes with dithiothreitol, the in vitro reductor for microsomal vitamin K epoxide reductase activity, reduced the warfarin binding. Vitamin K epoxide nor vitamin K affected the warfarin binding. Microsomes of the Welsh warfarin resistant genotype showed weak warfarin binding properties. The Scottish resistant variant, on the other hand, did not differ from sensitive microsomes. Warfarin binding was reduced in microsomes of rats to which S-warfarin was administered. The reduction in warfarin binding was linear with the inhibition of microsomal vitamin K epoxide reductase activity and was linear with the amount of S-warfarin present in the microsomes. The results show the microsomal 4-hydroxycoumarin binding to be related to the target enzyme vitamin K epoxide reductase.     

Activation and complexation of protein C and cleavage and decrease of protein S in plasma of patients with intravascular coagulation

Activated protein C (APC) is inhibited by two major plasma inhibitors (PCIs). To find evidence for in vivo complexation of APC, immunoblotting studies were performed on plasmas of 85 patients with suspected disseminated intravascular coagulation (DIC). Samples from 62 of these patients contained 5% to 35% of protein C antigen in APC:inhibitor complexes, indicating that protein C activation and inhibition had occurred. In 24 normal plasmas, no detectable APC:PCI complexes were observed (less than 5%). Patients with higher levels of complexes had more abnormal coagulation test data for DIC. The major band of APC complexes detected by anti-protein C antibodies did not react with antibodies to the heparin-dependent protein C inhibitor (PCI- 1) previously described. Rather, APC was complexed with another recently described plasma protein C inhibitor, PCI-2. Immunoblotting studies for protein S, the cofactor for APC, revealed that the majority of the DIC patient plasmas contained a higher than normal proportion of protein S in cleaved form, suggesting that protein S may have been proteolytically inactivated. Protein S total antigen levels were also found to be low in DIC patients, excluding those with malignancy. These studies support the hypothesis that the protein C pathway is activated during DIC.     

Lipohemarthrosis of the knee: a review of recent experiences

The radiographs of 268 patients with knee trauma were retrospectively reviewed. In 15 patients with intraarticular fracture, the images demonstrated fat-fluid levels. In 28 other patients with intraarticular fracture, only joint effusion without a fat-fluid level was depicted. The presence of a fat-fluid level in the knee indicated fracture in all patients in whom it was seen. The absence of such a level, however, did not exclude intraarticular fracture.     

Scedosporium endophthalmitis: two fatal disseminated cases of Scedosporium infection presenting with endophthalmitis

The incidence of disseminated infection with Scedosporium species is increasing in patients with haematological malignancy. Two fatal cases are reported of patients with acute myeloid leukaemia and neutropenia who presented with Scedosporium endophthalmitis. Diagnosis of fungal infection was delayed as blood and vitreous cultures were positive only after 3 days in patient 1 and blood culture was positive at 7 days in patient 2. Despite antifungal therapy with amphotericin B and additional fluconazole in patient 2, both patients died of overwhelming fungal septicaemia. Post‐mortem examination of the right globe in patient 1 showed haemorrhagic necrotizing chorioretinitis with numerous fungal hyphae in choroidal vessels, choroid, retina and vitreous. Scedosporium species are often resistant to conventional antifungal therapy including amphotericin B. Diagnosis is difficult and mortality in disseminated infection is high.     

Subtle gastric abnormalities in a canine model: detection with low-dose imaging with storage phosphors and its equivalence to conventional radiography

The authors compared low-dose (32% of standard exposure) storage phosphor digital imaging (system resolution: 0.2-mm pixels, 10 bits) with isovoltage 75-kVp conventional radiography (standard exposure) in the detection of subtle simulated gastric abnormalities by using air contrast barium studies. Subtle simulated abnormalities (3-7-mm polyps, 4-15-mm ulcer craters, 4-11-mm-diameter edema, and 11-12-mm linear ulcers) were produced in resected canine stomachs. Receiver operating characteristic analysis of 1,800 observations by six readers indicated that the digital images with and without high-frequency edge enhancement were equivalent to conventional radiographs (mean receiver operating characteristic areas [+/- standard deviation]: 0.76 +/- 0.06, 0.78 +/- 0.04, and 0.77 +/- 0.04, respectively). The accuracy of the diagnosis was equivalent for all three modalities. The following mean accuracies of negative and positive responses, respectively, for unenhanced digital, edge-enhanced digital, and conventional images were determined: 0.71 +/- 0.05 and 0.41 +/- 0.07, 0.71 +/- 0.04 and 0.51 +/- 0.09, and 0.68 +/- 0.04 and 0.43 +/- 0.05. It was concluded that low-dose storage phosphor air-contrast barium studies were equivalent to conventional radiography in the detection of subtle gastric abnormalities.     

Guar gum and similar soluble fibers in the regulation of cholesterol metabolism: Current understandings and future research priorities

The hypocholesterolemic effects associated with soluble fiber consumption are clear from animal model and human clinical investigations. Moreover, the modulation of whole-body cholesterol metabolism in response to dietary fiber consumption, including intestinal cholesterol absorption and fecal sterol and bile acid loss, has been the subject of many published reports. However, our understanding of how dietary fibers regulate molecular events at the gene/protein level and alter cellular cholesterol metabolism is limited. The modern emphasis on molecular nutrition and rapid progress in ‘high-dimensional’ biological techniques will permit further explorations of the role of genetic polymorphisms in determining the variable interindividual responses to soluble fibers. Furthermore, with traditional molecular biology tools and the application of ‘omic’ technology, specific insight into how fibers modulate the expression of genes and proteins that regulate intestinal cholesterol absorption and alter hepatic sterol balance will be gained. Detailed knowledge of the molecular mechanisms by which soluble fibers reduce plasma cholesterol concentrations is paramount to developing novel fiber-based “cocktails” that target specific metabolic pathways to gain maximal cholesterol reductions.     

Theoretical and methodological considerations in the measurement of spasticity

Purpose: To discuss the measurement of spasticity in the clinical and research environments, make recommendations based on the SPASM reviews of biomechanical, neurophysiological and clinical methods of measuring spasticity and indicate future developments of measurement tools. Method: Using the results of the systematic reviews of the biomechanical, neurophysiological and clinical approaches, methods were evaluated across three dimensions: (1) validity, reliability and sensitivity to change; (2) practical quality such as ease of use and (3) qualities specific to the measurement of spasticity, for example ability to be applied to different muscle groups. Methods were considered in terms of applicability to research and clinical applications. Results: A hierarchy of measurement approaches was identified from highly controlled and more objective (but unrelated to function) to ecologically valid, but less objective and subject to contamination from other variables. The lack of a precise definition of spasticity may account for the problem of developing a valid, reliable and sensitive method of measurement. The reviews have identified that some tests measure spasticity per se, some phenomena associated with spasticity or consequential to it and others the effect of spasticity on activity and participation and independence. Conclusions: Methods appropriate for use in research, particularly into the mechanism of spasticity did not satisfy the needs of the clinician and the need for an objective but clinically applicable tool was identified. A clinical assessment may need to generate more than one 'value' and should include evaluation of other components of the upper motor neurone syndrome. There is therefore a need for standardized protocols for 'best practice' in application of spasticity measurement tools and scales.