Correlation between serum levels of alanine aminotransferase and ferritin in male blood donors with antibody to hepatitis C virus

Chronic hepatitis C has been demonstrated to be associated with hepatic iron overload, and the hypothesis that the disease activity of hepatitis C is associated with iron cytotoxicity was tested in male volunteer blood donors. Sera with either antibody to hepatitis C virus or hepatitis B surface antigen were selected for determination of ferritin concentration and alanine aminotransferase activity. A correlation between serum ferritin concentration (Y; microgram/l) and alanine aminotransferase activity (X; IU/l) was found in donors with antibody to hepatitis C (log Y = 0.65 x log X + 0.98, r = 0.53, and P < 0.01). The correlation was lower in donors with hepatitis B surface antigen (r = 0.37; P < 0.01). Hepatitis C virus infection probably induces time-dependent iron accumulation associated with the progression of disease activity, while hepatitis B virus infection results in a variety of iron loads with different clinical features. The high disease activity related to hyperferritinemia suggests the presence of iron-induced liver damage in donors with hepatitis C.     

The effect of additional albumin with optimal concentration on the reperfusion after preservation of isolated rat hearts

Glucagon has been demonstrated to stimulate the uptake of bile acid in isolated rat hepatocytes (Am. J. Physiol., 249, G427 (1985)). In the present study, we determined the influence of glucagon on the hepatic transport of a bile acid, taurocholate (TCA), in isolated rat livers. A single-pass perfusion and a rapid-injection, multiple indicator dilution method were employed. The hepatic availability at steady-state was 0.04. With the presence of glucagon in the perfusate (from 10(-9) to 10(-7) M), the bile flow rate was stimulated by 30%, while hepatic availability was decreased from 0.04 to 0.02 with a stepwise increase in glucagon concentration. Thirty min after the infusion of glucagon (300 nM), [3H]TCA and [14C]inulin were injected in a bolus state into the portal vein, and the outflow was collected at 1.0 s intervals over 30 s. Glucagon decreased the instantaneous hepatic availability by 50% compared to the control level, and was thus compatible with the steady-state experiments. In the control experiment, the influx clearance (PSinf) was 20 times higher than the efflux clearance (PSeff). Glucagon (300 nM) in the perfusate enhanced PSinf by 50% of the control, whereas sequestration clearance (CLseq) and the biliary excretion rate constant remained unchanged. PSeff was stimulated to 2 times the control, but still remained much smaller than CLseq. Based on the comparison of PSinf, PSeff and CLseq, the rate-determining process of TCA hepatic elimination was the influx process in both the presence and absence of glucagon. Taken together, the enhancement of the influx process was responsible for the decrease in TCA hepatic availability caused by glucagon.(ABSTRACT TRUNCATED AT 250 WORDS)     

Connection‐Strength Estimation of Neuronal Networks by Fitting for Izhikevich Model

Recently, there has been abundant research using multineuron recording, but there are many problems with extracting the features from the obtained spike time series, which are huge in volume and complex. Here we introduce a new method of estimating synaptic connection strengths between neurons by fitting to the Izhikevich model by maximum likelihood estimation. We demonstrate that our method can estimate connection strengths from spike time series given by a simulated neural ensemble and can estimate nonconnectivity between two independent cultured neuronal networks. These results suggest that our method is applicable to network and plasticity analysis of neuronal networks.     

Chemoenzymatic synthesis of the branched oligosaccharides which correspond to the core structures of N-linked sugar chains

Synthetic routes are described to a partial structure common to all high mannose-type sugar chains and complex-type sugar chains based on a chemoenzymatic strategy which incorporates, (a) enzymatic synthesis of oligosaccharide blocks using glycosidases, and (b) chemical synthesis of the branching oligosaccharides via regioselective coupling. All reaction products correspond to key intermediates necessary for the construction of N-linked oligosaccharides and we have synthesized the branched tetra-manno-oligosaccharide high mannose-type sugar chain and the branched hexa-oligosaccharide complex-type sugar chain using this simple and direct method.     

Abnormal accumulation of copper in LEC rat liver induces expression of p53 and nuclear matrix-bound p21(waf 1/cip 1)

The LEC rat is an inbred mutant strain which spontaneously develops liver injury and subsequent liver cancer. Liver injury in LEC rats has recently been shown to be closely related to abnormal copper accumulation in the liver. Previously, we reported that LEC rat hepatocytes lose their growth potential, probably allowing selective growth of preneoplastic cells. In this study, to elucidate the effects of copper accumulation on the growth activity of LEC rat hepatocytes, we examined the growth activity and the expression of p53 and p21(waf 1/cip 1) in the livers of LEC rats fed on either a control or a low-copper diet. Potential for cell proliferation of hepatocytes obtained from normal diet fed LEC rats was almost comparable to that of the cells from age-matched Sprague-Dawley (SD) rats. Northern blot analysis showed that the expression of p53 and p21(waf 1/cip 1) was significantly high in the livers of LEC rats fed a control diet, while the expression of p53 and p21(waf 1/cip 1) in the LEC rats fed a low-copper diet was as low as that of SD rat livers. Western blot analysis consistently showed that the amount of p21(waf 1/cip 1) bound to the nuclear matrix scaffold of the LEC rat liver was reduced by feeding a low-copper diet. These findings suggest that abnormal accumulation of copper induced the expression of p53 and p21(waf 1/cip 1), resulting in the inhibition of cell proliferation of LEC rat hepatocytes.     

Blood supply to the retina in the laboratory shrew (Suncus murinus)

BACKGROUND: The benefit of splenectomy, performed for complications of chronic lymphocytic leukemia (CLL) including autoimmune hemolytic anemia, thrombocytopenia, hypersplenism, and symptomatic splenomegaly, has not been clearly demonstrated. The objective of this study was to determine if splenectomy achieves a predictable hematologic and survival advantage over conventional chemotherapy in patients with CLL. STUDY DESIGN: A retrospective review was performed of 77 consecutive patients with CLL who underwent splenectomy between 1970 and 1994 at the University of Texas M. D. Anderson Cancer Center. Indications for splenectomy, pre- and postoperative hematologic profiles, response to splenectomy, and time to progression and death were recorded. Kaplan-Meier life tables were constructed, and a comparison to an age- and gender-matched cohort of CLL patients treated with fludarabine and no splenectomy was performed using log rank statistical analysis. RESULTS: Seventy-six percent of the patients studied were Rai stage III/IV. Twenty of 29 patients with hemoglobin counts (Hb) < or = 10 g/dL and 11 of 18 patients with platelet counts (plt) < 50 x 10(9)/L achieved an excellent hematologic response to splenectomy. Splenectomy significantly improved survival in patients with Hb < or = 10 g/dL or plt < or = 50 x 10(9)/L (p = 0.025). Thrombocytopenia did not significantly increase postoperative morbidity, and mortality rate was not significantly different between treatment groups. CONCLUSIONS: Splenectomy significantly improves survival in selected subgroups of patients with advanced-stage CLL over that achieved with conventional chemotherapy. Based on these results, splenectomy should be performed early in the course of the disease in CLL patients with either an Hb < or = 10 g/dL or plt < or = 50 x 10(9)/L.     

Synthesis of an amphiphilic conjugated polymer through block copolymerization of phenylacetylene and (p-trityloxycarbonylphenyl)acetylene and the subsequent hydrolysis

Summary The polymerization of (p-trityloxycarbonylphenyl)acetylene (p-TrOCOPA) with [(nbd)RhCl]₂/Ph₂C=C(Ph)Li/Ph₃P ternary catalyst proceeded in a living fashion to provide polymer with low polydispersity index (M _w/M _n∼1.1) in good yield. Block copolymerizations of p-TrOCOPA with phenylacetylene (PA) selectively formed the corresponding block copolymers regardless of the order of monomer addition. The hydrolysis of the homo- and block copolymers of p-TrOCOPA catalyzed by hydrochloric acid gave carboxyl-containing hydrophilic homopolymer and amphiphilic block copolymers, respectively. The amphiphilic block copolymer formed micelles in solution and monomolecular membrane at the air-water interface. Received: 2 April 2001/Accepted: 17 April 2001     

Thin film solar cells based on microcrystalline silicon–germanium narrow-gap absorbers

We report on the improved performance of p–i–n junction solar cells incorporating hydrogenated microcrystalline silicon–germanium (μc-Si_1?xGe_x:H) absorber i-layers prepared by low-temperature (～200 °C) plasma-enhanced chemical vapor deposition. While the optical absorption increases with Ge content, the photocarrier transport in the solar cells for x>0.2 is dominated by the carrier recombination due to the increased dangling bond defects and the illumination-induced field distortion in the i-layer. In contrast, the solar cells with smaller Ge contents (x～0.2) exhibit better carrier collection characteristics with extended infrared sensitivities even higher than those of double-thickness μc-Si:H solar cells. As a result, we have achieved a 6.3% efficiency using a 1-μm-thick μc-Si_0.8Ge_0.2:H i-layer.     

Device simulation of carrier lifetime-controlled GTO

Recent development of power semiconductor devices has produced remarkable advances in power electronics. Among them, the gate turn-off thyristor (GTO) is one of the most important devices. Carrier lifetime-controlled devices have been proposed recently to realize low turn-off switching loss. Thus, computer simulation for the device is now necessary to predict its characteristics. In this study, we simulated a carrier lifetime-controlled GTO with the FEM program. Lifetime control, such as heavy metal diffusion and electron beam irradiation, showed a trade-off relation between on-state and turn-off conditions. Partial lifetime control, which generates lattice defects locally by light ion irradiation, showed the possibility of reducing turn-off loss and improving the trade-off relations. Furthermore, the numerical analyses showed relations between the location of the irradiated point and variations of the internal carrier distributions. © 1997 Scripta Technica, Inc. Electr Eng Jpn 119(1): 82–89.     

A soft-error-immune 0.9-ns 1.15-Mb ECL-CMOS SRAM with 30-ps 120 klogic gates and on-chip test circuitry

A soft-error-immune, 0.9-ns address access time, 2.0-ns read/write cycle time, 1.15-Mb emitter coupled logic (ECL)-CMOS SRAM with 30-ps 120 k ECL and CMOS logic gates has been developed using 0.3-μm BiCMOS technology. Four key developments ensuring good testability, reliability, and stability are on-chip test circuitry for precise measurement of access time and for multibit parallel testing, a memory-cell test technique for an ECL-CMOS SRAM, a highly stable current source with a simple design using a current mirror, and a soft-error-immune memory cell using a silicon-on-insulator (SOI) wafer. These techniques will be especially useful for making the ultrahigh-speed, high-density SRAM's used as cache and control storages in mainframe computers