An Artificial Gut/Absorption Simulator: Simultaneous Evaluation of Desupersaturation and Absorption from Ketoconazole Supersaturated Solutions

For supersaturating formulations of BCS-II compounds, which by definition have high intestinal permeability, a closed USP apparatus does not provide the necessary absorptive conditions during dissolution. To address this, an artificial gut simulator (AGS) has been constructed consisting of a 2.5 mL donor compartment in which a hollow fiber-based absorption module is suspended. Drug from donor diffuses across the hollow fiber membrane to be absorbed by the continuously flowing intraluminal receiver fluid. The membrane surface area and intraluminal fluid flow rate are tuned to obtain the physiologically observed absorption rate constant for a weakly basic, poorly water-soluble model compound, ketoconazole (KTZ). Supersaturated solutions of KTZ were generated in the donor in pH 6.5 phosphate buffer by the pH-shift method in the absence (closed system, control) and presence (open system, biorelevant) of an optimally or suboptimally tuned absorption module. Drug concentrations in the donor and intraluminal fluids were determined by in-line UV spectroscopy. The presence of an absorptive sink reduced the supersaturated solution's crystallization propensity, more so in the case of the optimally tuned AGS. This study demonstrates the significance of simulating absorption of drug at a physiological rate during dissolution studies, especially to predict the performance of formulations of BCS-II drugs.     

West Nile virus preferentially transports along motor neuron axons after sciatic nerve injection of hamsters

Prior findings led us to hypothesize that West Nile virus (WNV) preferentially transports along motor axons instead of sensory axons. WNV is known to undergo axonal transport in cell culture and in infected hamsters to infect motor neurons in the spinal cord. To investigate this hypothesis, WNV was injected directly into the left sciatic nerve of hamsters. WNV envelope-staining in these hamsters was only observed in motor neurons of the ipsilateral ventral horn of the spinal cord, but not in the dorsal root ganglion (DRG). To evaluate the consequence of motor neuron infection by WNV, the authors inoculated wheat germ agglutinin—horseradish peroxidase (WGA-HRP) 9 days after WNV sciatic nerve injection, and stained the spinal cord and the DRG for HRP activity 3 days later. The degree of HRP-staining in DRG was the same in WNV- and sham-infected animals, but the HRP-staining in the motor neuron in the ventral horn was considerably less for WNV-infected hamsters. To investigate the mechanism of WNV transport, hamsters were treated with colchicine, an inhibitor of membranous microtubule-mediated transport. The intensity of the WNV-stained area in the spinal cord of colchicine-treated hamsters at 6 days after WNV infection were significantly reduced (P≤.05) compared to the placebo-treated hamsters. These data suggest that WNV is preferentially transported through the motor axons, but not the sensory axons, to subsequently infect motor neurons and cause motor weakness and paralysis.     

GB9706．1-1995中漏电流测量装置（MD）的理解和标定

GB9706．1-1995是医用电气设备的安全通用要求，其中规定的漏电流要求是所有医用电气设备必须要达到的安全要求之一。同时，GB9705．1-1995给出了漏电流的测试方法及测量装置（MD），这里我们对该测量装置的特性及漏电流测试仪器的标定进行探讨。     

Effect of eucalyptus globulus oil on activation of nuclear factor-kappaB in THP-1 cells]

OBJECTIVE: To study the effect of eucalyptus globulus oil on the activity of nuclear factor-kappaB(NF-kappaB) in THP-1 cell line. METHODS: THP-1 cells were cultured with or without eucalyptus globulus oil at different concentrations (1, 10, 100 mg x L(-1), 30 min) before being stimulated with lipopolysaccharide (LPS, 1 mg x L(-1), 30 min). The location of NF-kappaB p65 subunit (NF-kappaB/p65) in THP-1 cells was detected by indirect immunofluorescence and laser scanning confocal microscope. The expression of NF-kappaB/p65 in nuclei was measured by Western-blot analysis. RESULT: The FITC-label NF-kappaB/p65 was mainly located in the nuclei after THP-1 cells were stimulated with LPS. Whereas, no fluorescence were seen in the nuclei of cells pretreated with eucalyptus globulus oil. This effect on NF-kappaB/p65 nuclear translocation was in a concentration dependent manner. CONCLUSION: Eucalyptus globulus oil inhibits the nuclear translocation of NF-kappaB induced by LPS in THP-1 cells.     

抽吸速度对一次性使用无菌注射器溶血率的影响分析

用不同容量的注射器在低、中、高不同抽吸血液的速度下进行溶血试验，以研究分析不同溶血结果的干扰原因实质。通过试验发现：抽吸小管的不同管径、管壁质量，内腔不同管径是机械性溶血干扰的直接原因。在分析了干扰和抽吸速度的灵敏关系后，认为抽吸速度的干扰具有随机性。因此，提出了萃取液试验方法以避开直接抽吸血液的机械性溶血干扰，并通过各种萃取时间试验证明了萃取液试验方法的可操作性、重复性、稳健性和准确性。     

Quantitative immunofluorescence assay for cyclobutyldithymidine dimers in individual mammalian cells

An indirect immunofluorescence procedure was developed for themeasurement of cyclobutyl dithymidine dimers in DNA of individualSyrian hamster embryo cells using a specific monoclonal antibody.A fluorescein-labeled secondary antibody and a fluorochromewhich binds to DNA were used to measure the photoproduct andtotal DNA in the same nucleus. Fluorescence intensity was quantitatedwith a computer-assisted microfluorometric system which wascalibrated with a uranyl oxide impregnated glass slide. Similardose-response curves, i.e. normalized fluorescence intensityplotted as a function of dose of germicidal irradiation, wereobtained with two different cell types. Normalized fluorescenceintensity per nucleus was related to thymidine dimer contentwith a competitive enzyme-linked imnmunosorbent assay usingDNA isolated from cells given doses of germicidal irradiationidentical to those used in the immunofluorescence assay. Thymidinedimer levels produced by 10 J/m² of germicidal irradiation (8x10⁵/nucleus)and which allow for 15–30% cell survival can readily bedetected. The specific monoclonal antibody was labeled withtritium and used in the immunofluorescence assay to relate thenumber of antibodies bound to the number of thynudine dimersper cell. The data revealed that 45% of the thymidine dimersin cells exposed to 100 J/m² of germicidal irradiation and essentiallyall the T<>T in cells receiving 20 J/m² were being detectedin the indirect immunofluorescence assay. This technique canprovide a sensitive means for measuring various types of DNAdamage in individual cells given that the appropriate probesare available. It can be especially useful for monitoring occupationallyor environmentally exposed populations where usually only smallsamples of cells or tissues are available.     

The Broiler Chicken as a Model for Immunotoxicity Assessment: 1. Standardization of in Vitro Immunological Assays

The Broiler Chicken as a Model for Immunotoxicity Assessment.1. Standardization of in Vitro Immunological Assays. BAECHER-STEPPAN,L., NAKAUE, H. S., MATSUMOTO, M., GAINER, J. H., AND KERKVLIET,N. I. (1989). Fundam. Appl. Toxicol. 12, 773–786. Thebroiler chicken was developed as an alternative animal modelto laboratory rodents for immunotoxico-logic assessment. Invivo treatment with 100–200 mg/kg cyclophosphamide (CY)was used as a known immunosuppressive treatment to standardizethe assay systems. Protocols for assessing specific immunologicalfunctions were developed in specific pathogen-free (SPF) broilersto measure lymphocyte blastogenesis to T-cell (concanavalinA and phytohemagglutinin) and B cell (Staphylococcus aureuscells) mitogens, delayed-type hypersensitivity (Dm) to tuberculin,natural killer (NK) cell cytotoxicity, plaque-forming cell (PFC)response to sheep red blood cells (SRBC), and serum antibodytiters to SRBC. CY was an effective immunosuppressant in thebroiler system for assessment of lymphocyte responsiveness tomitogenic stimulation, DTH reactivity, and the antibody responceto SRBC as assessed by PFC and serum antibody titers. NK cytotoxicitywas not altered on a cellular level following treatment withCY at a dose that preduced greater than 75% depletion of spleencellularity. However, under these conditions, it must bc assumedthat the capacity of CY-treated birds to mediate NK effectorfunctions would be reduced. These results demonstrate the applicabilityof the broiler chicken as an animal model for immunotoxicitytesting.     

Identification of a Rough Strain of Escherichia coli O157:H7 That Produces No Detectable O157 Antigen

MA6, an O157:H7-like strain, did not react with most anti-O157 kits examined; however, it had the rfbE gene that is essential for O157 expression and carried O157:H7 virulence factors. Lipopolysaccharide analysis showed that MA6 is a rough strain that does not produce the O157 antigen, but genetically, it belongs in the O157:H7 clonal group.