Histopathological studies of extracted whole lunate bones obtained from 10 patients with Stage 3 Kienböck’s disease at surgery for tendon-ball replacement were correlated with magnetic resonance imaging (MRI), computed tomography (CT) and tomography images made prior to surgery. A reforming zone, or a reactive interface between the reactive new bone and granulation tissue formation, and new vascularization were observed surrounding the bone necrosis area showing empty lacunae, fatty necrosis, and disappearance of osteoid. Findings of CT, tomography and microradiography of slices of extracted lunate bone confirmed that fractures of the articular cartilage and the subchondral bone occurred secondarily by overloading, and showed the extent of the collapsed area of the lunate. MRI showed complete loss of signal intensity in T1 images of the lesion of the lunate in advanced Stage 3 Kienböck’s disease. MRI is at present unable to distinguish bone necrosis, the histological reactive interface or surrounding hyperaemia in detail. However, the low-intensity arc, or the reactive interface present on MRI in early Stage 3, sometimes correlates with the histological findings of osteoid and granulation zones.
Insulin resistance is one of the determinants of post-prandial hyperglycaemia. Recently, acarbose, an α-glucosidase inhibitor that delays the absorption of carbohydrates from the small intestine, has been found to reduce the incidence of cardiovascular disease in patients with impaired glucose tolerance or diabetes. However, the molecular mechanism by which acarbose inhibits cardiovascular events remains unknown. In this study, we examined whether oral administration of acarbose could suppress expression of monocyte chemoattractant protein-1 (MCP-1) in fructose-fed rats, a widely used animal model of insulin resistance. Serum MCP-1 levels were elevated in fructose-fed rats after 4 weeks. Acarbose treatment for 4 weeks reduced the fructose-induced elevation of serum MCP-1 levels. Acarbose treatment for 8 weeks decreased MCP-1 mRNA levels in the aortae of fructose-fed rats. These results suggest that the cardioprotective effects of acarbose could be due, at least in part, to the suppression of MCP-1 expression.
Pigment epithelium-derived factor (PEDF) is a natural extracellular component of the retina with neuronal differentiating activity. Recently, decreased levels of PEDF in the mammalian eye have been shown to participate in the pathogenesis of diabetic retinopathy In addition, advanced glycation end products (AGEs), senescent macroprotein derivatives that form at an accelerated rate under diabetes, have also been implicated in the development and progression of diabetic retinopathy. However the role of AGEs in decreased levels of PEDF in the eye remains to be elucidated. In this study, we examined the effects of AGEs on PEDF gene expression in microvascular endothelial cells (ECs). Various types of immunochemically distinct AGEs, which were prepared in vitro by incubating bovine serum albumin with glucose, glyceraldehyde or glycolaldehyde, significantly decreased endothelial mRNA levels of PEDF Furthermore, H2O2 dose-dependently suppressed PEDF gene expression in ECs. Our present results suggest that AGEs could down-regulate mRNA levels of PEDF in ECs, probably via oxidative stress generation. The deleterious effects of AGEs on diabetic retinopathy could be due, at least in part, to their PEDF-inhibitory properties.
The X-ray pulsar Her X-1 was observed in an on-state during its 35th cycle of activity in May, 1983 using the gas scintillation proportional counter (GSPC) array of the Tenma X-ray astronomy satellite. The outstanding features observed during the declining phase of the on-state included: a sharp decrease in the main X-ray pulse amplitude; and a steady increase in the column density of cool matter. On the basis of the spectral shape of the pulses, it is suggested that the main phase was attenuated due to electron scattering of the X-ray beam in a highly ionized medium located 3 x 10 to the 8th cm from the neutron star. Near the end of the on-state, the main pulse totally disappeared and a plain sinusoidal profile was observed. The observed pulse profiles are reproduced in graphic form.
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