F-19 MR imaging of glucose metabolism in the rabbit

Noninvasive metabolic magnetic resonance (MR) imaging reflecting glucose metabolism in the aldose-reductase-sorbitol (ARS) pathway was performed in the rabbit head; after administration of the fluorinated glucose analogue 3-fluoro-3-deoxy-D-glucose (3FD-glucose), fluorine-19 images were generated. Images of 3FD-glucose showed significant 3FD-glucose uptake by adipose tissue, indicating its buffering effects in case of excess loads of glucose. Images of 3-fluoro-3-deoxy-D-sorbitol (3FD-sorbitol) demonstrated the spatial distribution of aldose reductase activities and significant sorbitol accumulation in the lens. Images of 3-fluoro-3-deoxy-D-fructose (3FD-fructose) showed preferential uptake of fructose by muscle tissue. The extremely low toxicity of 3FD-glucose indicates promise for its clinical application in metabolic imaging.     

Factors linked to bacterial vaginosis in nonpregnant women

OBJECTIVES: The purposes of this study were to test the hypothesis that vaginal douching is linked to bacterial vaginosis in both symptomatic and asymptomatic women and to identify other demographic, reproductive, and lifestyle factors associated with bacterial vaginosis. METHODS: In this cross-sectional study involving 3 clinic sites, 496 nonpregnant women completed a self-administered questionnaire. Their vaginal smears were assessed and cross-validated for bacterial vaginosis. RESULTS: The prevalence of bacterial vaginosis across clinics ranged from 15% to 30%. In analyses restricted to site 1, adjusted odds ratios (ORs) for bacterial vaginosis remained significant for African American women with 13 or fewer years of education (OR = 5.5, 95% confidence interval [CI] = 2.1, 14.5), hormone use within the past 6 months (OR = 0.5, 95% CI = 0.2, 0.8), and vaginal douching within the past 2 months (OR = 2.9, 95% CI = 1.5, 5.6). CONCLUSIONS: Two lifestyle factors emerge as strongly associated with bacterial vaginosis: systemic contraceptives appear protective, whereas douching is linked to an increase in prevalence. The temporal relationship between douching and bacterial vaginosis needs further clarification.     

Prognostic value of negative dobutamine stress echo in women with intermediate probability of coronary artery disease

Women with an intermediate pretest probability of coronary artery disease represent a significant proportion of patients referred for the investigation of chest pain. Dobutamine stress echocardiography can be used to restratify these patients into a low-risk group without resorting to cardiac catheterization.     

Digital beam attenuator technique for compensated chest radiography

The feasibility of producing patient-specific beam attenuators for chest radiography has been investigated using an anthropomorphic phantom and a human volunteer. A low-dose test exposure is digitized, processed, and used to print a small cerium filter, which is placed in the x-ray beam near the collimator. The final radiograph is recorded on film. The technique results in relatively uniform film exposure, so that structures in all regions of the chest are simultaneously displayed with optimal film contrast. The equalized exposure improves image quality in the normally underpenetrated regions and reduces the role of cross-scatter from the lungs. The image is analogous to optical or computer-processed unsharp masking techniques, but the processing is accomplished in the x-ray beam and results in an improved exposure distribution, giving advantages that cannot be achieved with image processing techniques alone.     

Antidepressant drug treatment for poststroke depression: retrospective study

The records of 60 patients evaluated psychiatrically for major depression after stroke were reviewed retrospectively. Forty-two patients were treated with one of several "cyclic" antidepressant drugs, and 18 received no drug treatment. Objective ratings, based on current standard criteria for "major depression" (DSM-III), were used to establish degree of depression at initial evaluation and within six weeks after the start of treatment. Overall, improvement in depression was no greater in treated than in untreated patients. However, a subgroup (40%) of drug-treated patients was identified with a substantial (greater than or equal to 40%) improvement in depression ratings. Only three (17%) untreated patients showed a comparable improvement within a similar time period. Eighteen (43%) of the drug-treated patients experienced minor side effects (especially mild sedation), but only three (7%) experienced major side effects that required cessation of treatment. The degree of initial depression was not correlated with the degree of motor or functional disability among patients. These results suggest that antidepressants may constitute safe and effective treatment for some patients with poststroke depression, and further studies of the pathophysiology and treatment of this disorder are indicated.     

Computational Fluid Dynamics Study of the Effects of Surface Roughness on Permeability and Fluid Flow-Induced Wall Shear Stress in Scaffolds

In this work, we investigated surface roughness effects on bone scaffold permeability and fluid flow-induced wall shear stress (WSS) using computational fluid dynamics (CFD) analysis. Scaffolds are made of interconnected microchannels, whose fluid flow can be examined from the perspective of fluid flow dynamics. Given that the roughness of microchannel surfaces serves a non-negligible function in the fluid dynamics within the channels, it is believed that the wall roughness of scaffolds can play an important role in their permeability and WSS. Given the criticality of permeability and WSS in the effective biological functioning of scaffolds, we investigated manufacturing-induced surface roughness effects on the two aforementioned biocompatibility characteristics. To this end, three scaffolds with square pores of different sizes (300, 600, and 900 µm) and identical porosity (63%) were designed. Six roughness levels (0, 4, 8, 12, 16, and 20 µm) were established for the scaffold walls, thus enabling us to develop 18 scaffold models. The pressure drop and WSS in the scaffolds were then measured by CFD. Scaffold permeability was calculated using Darcy’s law, with reference to geometrical parameters and the pressure drop derived from the CFD analysis. In all the scaffolds, high roughness decreased permeability and WSS. A significant difference in WSS reduction was found between the models with smooth scaffolds and the models with scaffolds that had a roughness of 20 µm. Except for the scaffold with a pore size of 300 µm, all the others showed no considerable change in permeability at different roughness levels.     

Behavioral evidence of thermal hyperalgesia in non-obese diabetic mice with and without insulin-dependent diabetes

The non-obese diabetic (NOD) mouse, a model of Type 1 diabetes in humans, has proven useful for the study of genetic, immunologic and epidemiologic aspects of inherited diabetes. Behavioral evidence of hyperalgesia may also be present in the NOD mouse but has not been described. This study examined NOD mice with (NOD+) and without (NOD−) insulin-dependent diabetes, and control strain (ILI) mice for evidence of hyperalgesia to a noxious thermal stimulus. Interestingly, both NOD+ and NOD− mice showed reduced mean hindpaw withdrawal latencies when compared with non-diabetic ILI mice. NOD+ and NOD− mice were also abnormal in their general appearance, activity level, posture, gait and muscle bulk when compared with ILI mice. These findings raise the possibility that hyperalgesia in insulin-dependent NOD mice, or insulin-dependent humans with Type 1 diabetes, may be independent of diabetes and due to a primary disturbance within sensory pathways.