Physical and rheological properties of xanthan gum agglomerated in fluidized bed: Effect of HPMC as a binder.

Physical and rheological properties of agglomerated xanthan gum (XG), commonly used as a food thickener for the management of the patients with dysphagia (swallowing difficulty), were investigated at different concentrations (0, 2, 4, and 6% w/w) of hydroxypropyl methylcellulose (HPMC) as a binder in the fluidized bed agglomeration process. Flow characteristics of agglomerated XG powder were evaluated using Carr index (CI) and Hausner ratio (HR). The agglomerated XG powders obtained by HPMC binder exhibited a better flowability and higher porosity than the agglomerated powder without binder due to the size enlargement of XG powder. Dynamic moduli (G' and G") of agglomerated XG powders at 2% and 4% HPMC were significantly higher than those of other powders. The tan δ values of agglomerated powders with HPMC binder were much lower than that of an agglomerated powder without HPMC, indicating that their elastic properties were enhanced because of the addition of HPMC binder. Results suggest that the use of HPMC in agglomeration process could considerably enhance the flow characteristics and rheological properties of XG powder.

Reductive surface synthesis of gold nanoparticles on silicate glass and their biochemical sensor applications.

Gold nanoparticles (Au NPs) were directly synthesized on the surface of polyvinylsilazane (PVSZ, -[(vinyl)SiH-NH2]-) without use of extra reductive additives. The reductive Si-H functional groups on the surface of cured PVSZ acted as surface bound reducing agents to form gold metal when contacted with an aqueous Au precursor (HAuCl4) solution, leading to formation of Au NPs adhered to silicate glass surface. The Au NPs-silicate platforms were preliminarily tested to detect Rhodamine B (1 µM) by surface enhanced Raman scattering. Furthermore, gold microelectrode obtained by post-chemical plating was used as an integrated amperometric detection element in the polydimethylsilane-glass hybrid microfluidic chip.

Prevention of primary nonfunction after canine liver allotransplantation: the effect of gadolinium chloride.

PURPOSE: Effective suppression of Kupffer cell function is believed to contribute to the prevention of preservation/reperfusion injury. In this study, effect of gadolinium, a synthetic Kupffer cell suppressant, on the reperfusion injury was examined using a canine partial liver transplantation model. METHODS: About a 70% partial liver segment was harvested and reimplanted in a mongrel recipient dog weighing 20 to 25 kg. Gadolinium chloride (10 mg/kg) was infused via the cephalic vein 24 hours before harvest of the partial liver (gadolinium group, n = 5). Serum aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and morphologic grading of graft were compared with those of a control group (n = 5). Statistical analysis was done with an independent t-test. RESULTS: Average total ischemic time was 4 hours and 27 minutes. At 1 hour after reperfusion, there were no significant differences in AST, ALP, or LDH levels, or pathologic scores. At 48 hours after reperfusion, AST (P = .03) and LDH (P = .05) levels were significantly lower in the gadolinium group. CONCLUSION: Kupffer cell blockade using gadolinium chloride may be effective to reduce ischemia reperfusion injury, but the effect is not evident at an early stage of reperfusion.

The effect of a nitric oxide donor on endogenous endothelin-1 expression in renal ischemia/reperfusion injury.

The balance between nitric oxide (NO) and endothelin-1 (ET-1) production is essential to the vascular function that controls organ perfusion. Elevated ET-1 levels in the peritubular capillary network following renal transplantation may be associated with renal allograft rejection. Administration of a nitric oxide donor during the preischemic period has been shown to protect kidney against ischemia-reperfusion injury, but the mechanism underlying this therapeutic benefit remains incompletely understood. We hypothesized that early administration of the NO donor sodium nitroprusside (SNP) may suppress ET-1, thereby improving renal function in an ischemia/reperfusion injury. Sprague-Dawley rats were subjected to 60 minutes of renal warm ischemia and contralateral nephrectomy. Renal biopsies were performed prior to ischemia and reperfusion, and at 1 hour and 48 hours after reperfusion. The animals were divided into four groups: sham group without warm ischemia; early SNP group (SNP given before ischemia); late SNP group (SNP given before reperfusion); and ischemic control. ET-1 expression was assessed by semiquantitative analysis with immunohistochemical stain using ET-1 monoclonal antibody and hematoxylin-eosin staining. Serum creatinine was measured at 48 hours after reperfusion. There were significant improvements in all parameters of the early compared with the late SNP group and the ischemic control, but there was no difference between the late SNP group and the ischemic control. These data suggest that early administration of SNP in renal ischemia-reperfusion improves renal function by suppressing ET-1 expression.