Cerebral structural alterations in the patients undergoing postherpetic neuralgia: A VBM-MRI study.

This study aimed to investigate the changes in gray matter (GM) volume and density in patients with postherpetic neuralgia (PHN). Using voxel-based morphometry (VBM), the differences in cerebral GM volume and concentration between 25 PHN patients and 25 healthy controls with similar gender ratios, ages, and education were compared. Meanwhile, correlation analysis was performed between the value of GM volume/concentration in the brain areas with discrepancy and the visual analog scale (VAS) score/lesion duration. The global GM volume in PHN patients was lower than that of healthy controls, while the total volume of cerebrospinal fluid in PHN patients was higher than that of healthy controls. In PHN patients, the GM volume decreased in the striatum, cerebellum, precentral gyrus, middle frontal gyrus, parahippocampal gyrus, postcentral gyrus, and so forth; the GM concentration decreased in the striatum, insula, middle and posterior cingulate, and superior temporal gyrus. There was a negative correlation between GM concentration in the right parahippocampal gyrus and the VAS in patients with PHN. In PHN patients, GM volume and density in the brain regions involved in nociceptive sensation, pain perception, and integration decreased significantly. The interaction between chronic pain of PHN and alteration of the cerebral structure may contribute to the occurrence and development of PHN.

Early Intervention of Gastrodin Improved Motor Learning in Diabetic Rats Through Ameliorating Vascular Dysfunction.

The mechanism of cognitive dysfunction in diabetes is still unclear. Recently, studies have shown that the cerebellum is involved in cognition. Furthermore, diabetes-induced cerebellar alterations is related to vascular changes. Therefore, we aimed to explore the roles of vascular function in diabetes-induced cerebellar damage and motor learning deficits. Type 1 diabetes was induced by a single injection of streptozotocin in Sprague-Dawley rats. Motor learning was assessed by beam walk test and beam balance test. The pathological changes of the cerebellum were assessed by Hematoxylin and eosin staining and Nissl staining. Apoptosis was evaluated by anti-caspase-3 immunostaining. Protein expression was evaluated by western blotting and double immunofluorescence. Our results have shown that motor learning was impaired in diabetic rats, coupled with damaged Purkinje cells and decreased capillary density in the cerebellum. In addition, the protein expression of neuronal NOS, inducible NOS, endothelial NOS, total nitric oxide, vascular endothelial growth factor and its cognate receptor Flk-1 was decreased in the cerebellum. Gastrodin treatment ameliorated neuronal damage and restored protein expression of relevant factors. Arising from the above, it is suggested that vascular dysfunction and NO signaling deficits in the cerebellum may be the underlying mechanism of early manifestations of cognitive impairment in diabetes, which could be ameliorated by gastrodin intervention.

Production of 6-aminopenicillanic acid in aqueous two-phase systems by recombinant Escherichia coli with intracellular penicillin acylase.

Bioconversion of penicillin G in PEG 20000/dextran T 70 aqueous two-phase systems was achieved using the recombinant Escherichia coli A56 (ppA22) with an intracellular penicillin acylase as catalyst. The best conversion conditions were attained for: 7% (w/v) substrate (penicillin G), enzyme activity in bottom phase 52 U ml(-1), pH 7.8, temperature 37 degrees C, reaction time 40 min. Five repeated batches could be performed in these conditions. Conversions ratios between 0.9-0.99 mol of 6-aminopenicillanic acid (6-APA) per mol of penicillin G, were obtained and volumetric productivity was 3.6-4.6 micromol min(-1) ml(-1). In addition the product 6-APA could be directly crystallized from the top phase with a purity of 96%.

Affinity Chromatography of Urokinase Using Cefazoline as a Ligand.

Sepharose 4B-based affinity adsorbent was prepared using cefazoline as a ligand, and epichlorohydrin as an activator. The density of the ligand in the affinity adsorbents was about 43 &mgr;mol/g wet gel. The optimal adsorption pH for urokinase was 6.0, and the optimal adsorption salt concentration was 1.0 mol/L NaCl. The optimal conditions of elution were 0.1 mol/L glycine buffer, pH 9.0, containing 0.5 mol/L NaCl. A crude urokinase with specific activity 500 u/mg protein was purified on an affinity chromatography column (1 cm x 12 cm), yielding a product of specific activity of 49 300 u/mg with 78% recovery and 98.6-fold purification.