Nanofibrillated Cellulose-Enzyme Assemblies for Enhanced Biotransformations with In Situ Cofactor Regeneration.

We report herein the use of nanofibrillated cellulose (NFC) for development of enzyme assemblies in an oriented manner for biotransformation with in situ cofactor regeneration. This is achieved by developing fusion protein enzymes with cellulose-specific binding domains. Specifically, lactate dehydrogenase and NADH oxidase were fused with a cellulose binding domain, which enabled both enzyme recovery and assembling in essentially one single step by using NFC.

Cellulosic carbon fibers with branching carbon nanotubes for enhanced electrochemical activities for bioprocessing applications.

Renewable biobased carbon fibers are promising materials for large-scale electrochemical applications including chemical processing, energy storage, and biofuel cells. Their performance is, however, often limited by low activity. Herein we report that branching carbon nanotubes can enhance the activity of carbonized cellulosic fibers, such that the oxidation potential of NAD(H) was reduced to 0.

A single carbon fiber microelectrode with branching carbon nanotubes for bioelectrochemical processes.

Carbon fiber electrodes are greatly promising for microelectronic applications including high performance biosensors, miniaturized transmitters, and energy storage and generation devices. For biosensor applications, one drawback of using carbon fiber microelectrodes, especially single fiber electrodes, is the weak electronic signals, a consequence of low surface area of fibers, which ultimately limit the sensitivity of the sensors. In this paper, we report a novel single fiber microelectrode with branched carbon nanotubes for enhanced sensing performance.

[A retrospective cohort study on mortality among silicotic workers in Hong Kong with emphasis on lung cancer].

Objective: To investigate the relationship between silica or silicosis and lung cancer in a large cohort of silicotic workers in Hong Kong.

Methods: All workers with silicosis in Hong Kong diagnosed between 1981 and 1998 were followed up till the end of 1999 to ascertain their vital status and causes of death, using the corresponding mortality rates of Hong Kong males of the same period as external comparison. Standardized mortality ratios (SMR) for lung cancer and other major causes of death were calculated.

Trace metals in mussels from mariculture zones, Hong Kong.

In 1997, concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and nickel (Ni) were analysed in green-lipped mussels (Perna viridis) from three mariculture zones located in the north-east (Kat O), south (Lo Tik Wan) and to the west (Ma Wan) of Hong Kong. Spatial differences in the concentration of metals were found, chromium and copper were higher at Ma Wan and Lo Tik Wan compared to Kat O in the north-east. In contrast, the highest levels of lead (mean = 4.

Xenotransplantation of adult porcine islets in diabetic mice. A study of UVB irradiation, cryopreservation and immunosuppression on graft survival time.

The major obstacle for successful xenotransplantation of islets to large animals and human diabetics is the host rejection. To address the rejection problem, we studied the efficacy of UV-B irradiation, cryopreservation and immunosuppression on the in vivo functional time and immunogenicity of adult porcine islets (PI) in outbred CD1 mice. Exposure of PI to UV-B irradiation between 300-1800J/M2 did not affect the cellular viability as assessed by fluorescein diacetate or their daily insulin secretion in vitro.

Prolongation of pig islet xenograft survival in rats immunosuppressed with FK506.

FK506 a new and potent immunosuppressive agent has been shown to be effective in prolonging pancreatic islet allograft survival. The present study was to determine its efficacy in prolonging pig islet xenotransplantation in two different strains of rat recipients. A total of two dosages of FK506 at 1 or 2 mg/kg per day for 2 weeks and then at weekly intervals were tested as monotherapy for their effect on the survival of renal subcapsular xenografts of purified or impure adult pig islets in inbred ACI and outbred Wistar rats.

Effect of FK506 on rat Leydig cell function--in vivo and in vitro study.

FK506, a macrolide antibiotic, is a potent immunosuppressant and has a biological effect similar to that of cyclosporin A (CsA). In this study, the in vivo and in vitro effects of FK506 on rat Leydig cell function were investigated. In vivo, basal testosterone levels and secretion in response to human chorionic gonadotropin (hCG) stimulation in ACl rats treated with intramuscular (IM) injections of FK506 at a dosage of 1 or 2 mg/kg/d for 14 days were not different from those of age-matched normal controls.

Cryopreservation of rat Leydig cells for in vitro and in vivo studies.

Leydig cells lose their ability to secrete testosterone following short-term in vitro culture. A procedure for effective storage of these cells would be useful. In this study, rat Leydig cells were cryopreserved in the presence of 10, 15 or 20% dimethylsulfoxide (DMSO) at approximately 1 degree C/min to -70 degrees C and then stored in LN2.

Successful islet allotransplantation in diabetic rats immunosuppressed with FK506: a functional and immunological study.

The effect of a novel immunosuppressive agent, FK506, on fresh islet allografts was evaluated in diabetic rats across major histocompatibility complex (MHC) barriers with respect to the transplantation (TR) site, islet source, treatment regimen, and antidonor antibody (Ab) titers of the recipients after TR. The functional periods of Wistar (Wi) islets transplanted under kidney capsule (KC) or intraportally (IPo) and of a mixture of Wi and Lewis (Le) islets under KC or IPo in nonimmunosuppressed ACI rat recipients were 6.9 +/- 0.

A diabetic rabbit model for pig islet xenotransplantation.

An alloxan-diabetic rabbit model was established for the testing of the function of discordant xenogeneic pig islets isolated and purified from adult pig pancreata. The functional state of the pig islet transplants and immunological state of the rabbit recipients were assessed. Intraportal transplantation of 0.