Evidence for hepatocyte differentiation from embryonic stem cells in vitro

We confirmed hepatocyte differentiation from embryonic stem (ES) cells in vitro. RT-PCR analysis revealed that a broad range of hepatic gene expression was observed in ES cells differentiated through formation of embryoid bodies (EBs) and its attachment culture. Quantitative PCR analysis revealed that hepatic gene expression related to early and late-stage liver development were enhanced through in vitro differentiation of ES cells. The presence of albumin-producing cells in the peripheral region of attached EBs was confirmed by immunocytochemical analysis. Future experiments will reveal the molecules that induce hepatocyte differentiation from ES cells in vitro. This research will provide systems for the investigation of mechanisms in liver development and establish a method of ES cell-based therapy for liver diseases.     

Ca2+ entry channels involved in contractions of rat aorta induced by endothelin-1, noradrenaline,and vasopressin

Endothelin-1 (ET-1) has been shown to activate three types of Ca2+ channel, namely two Ca2+-permeable nonselective cation channels (designated NSCC-1 and NSCC-2) and a store-operated Ca2+ channel (SOCC), and that these channels can be discriminated by Ca2+ channel blockers such as LOE 908 (a blocker of NSCC-1 and NSCC-2) and SK&F 96365 (a blocker of NSCC-2 and SOCC). This study pharmacologically compared Ca2+ entry channels involved in contractions of rat thoracic aorta without endothelium induced by ET-1, noradrenaline (NA), or arginine-vasopressin (AVP). These agonists-induced contractions of aortic rings without endothelium and increases in the intracellular free Ca2+ concentration ([Ca2+]i) of cultured aortic smooth muscle cells were abolished by removal of extracellular Ca2+. A blocker of L-type voltage-operated Ca2+ channel (VOCC), nifedipine had no effect on the responses to ET-1, but it suppressed the responses to NA and AVP to 70% and 65% of control responses, respectively. LOE 908 partially suppressed the nifedipine-resistant responses to ET-1 and AVP, but not those to NA. SK&F 96365 also partially suppressed the nifedipine-resistant responses to ET-1 and AVP, whereas it abolished the responses to NA. LOE 908 in combination with SK&F 96365 abolished the nifedipine-resistant responses to either of the agonists. These results show that the contraction of rat aorta involves different Ca2+ entry channel depending on agonists: (a) NSCC-1, NSCC-2, and SOCC for ET-1; (b) VOCC and SOCC for NA; and (c) VOCC, NSCC-1, NSCC-2, and SOCC for AVP.     

Inhalation toxicokinetics of p-dichlorobenzene and daily absorption and internal accumulation in chronic low-level exposure to humans

Inhalation toxicokinetics of p-dichlorobenzene ( p-DCB) in humans was evaluated, and the amounts of daily absorption and internal accumulation were estimated in order to obtain fundamental data for the risk assessment of chronic low-level exposure in the general population. Seven male subjects continuously inhaled about 2.5 ppm of p-DCB vapor for 1 h, and the concentration-time courses of p-DCB in their exhaled air and serum and of urinary 2,5-dichlorophenol (2,5-DCP), a major metabolite of p-DCB, were examined. The toxicokinetics of p-DCB was evaluated on the basis of the time courses using a linear two-compartment model. The amounts of p-DCB absorbed daily and the internal accumulation in chronic low-level exposure were extrapolated using the estimated toxicokinetic parameters. p-DCB was transferred from inhaled air to the body with a constant high absorption rate during exposure. The major route for elimination from the body was urinary excretion followed by metabolism, not exhalation. However, during 9-11 h after the start of exposure, the fraction of p-DCB excreted in urine was only 5-16% of the amount absorbed. Furthermore, most of the absorbed p-DCB seemed to be distributed rapidly to the tissues, such as fat, according to toxicokinetic analysis. Consequently, p-DCB seems to require a long time to be completely eliminated from the body. The amounts of daily absorption and internal accumulation were extrapolated to average 0.27 mg/day and 2.9 mg, respectively, in the subjects exposed chronically to 1 ppb of p-DCB. The amount absorbed daily agreed approximately with that extrapolated from rats which inhaled p-DCB in our previous study.     

Predictors of functional status among independent and homebound community dwelling elderly: physical,psychological, and social parameters

PURPOSE: The purpose of this study was to determine changes in functional status of Japanese community-dwelling elderly, and to identify physical, psychological, and social factors that predict functional change in a 1-year longitudinal study. METHODS: A cohort of people 65 years of age and over living in two cities in Yamagata Prefecture were followed for one year. The employed degree of independent criteria developed by the Ministry of Health and Welfare had nine levels. Subjects were classified as independent (rank J) and homebound (rank A) and numbered 112 and 53, respectively. Data on demographic, physical, psychological, and social variables were collected in 1997 by mail and interview during house visits. Death and change in functional status were checked in 1998. RESULTS: At follow-up, 1.0% of independent elders had died. Likewise, of the homebound elderly 7.7% had died. Change in functional status between the baseline and follow-up surveys were similar for both sexes and all age groups. According to nine levels criteria, rates for a good and a poor functional status of independent elderly were much the same at the baseline. Among homebound elders, 35.4% demonstrated improvement in the functional status and 14.6% deterioration. Among independent elderly, worsening of the functional status was significantly displayed, particularly with regard to hearing deficits, hospitalization within the past one year, loss of self-efficacy, fair or poor subjective health and poor functional ability. Among homebound elderly, worsening was significantly displayed in term of incontinence and poor self-efficacy. CONCLUSIONS: When functional status at baseline was poor, deterioration was evident at follow-up survey, independent of the sex or age group. Transition in functional status can be dynamic, and improvement was more usual than worsening among homebound elderly. Our results show that increase in self-efficacy can be an effective target in programs for improvement of functional status and for prevention of functional deterioration among the independent and homebound elderly of both sexes.     

Enhanced radiation killing by 5-fluorouracil of biliary tract cancer cell lines

Despite the frequent clinical use of 5-fluorouracil (5-FU) in combination with radiotherapy for patients with biliary tract cancers, data remain scarce concerning specifically the influence of 5-FU on the sensitivity of these cancer cells to radiation. The present study was carried out to evaluate the effects of concomitant treatment with 5-FU on radiation-induced cell killing in two established human biliary tract cancer cell lines (Mz-ChA-2 and SK-ChA-1 cells). These lines were chosen as we have previously shown that SK-ChA-1 cells are significantly more resistant to both radiation and 5-FU than Mz-ChA-2 cells. Clonogenic survival was employed as the end-point for cell killing. Administration of 5-FU at LD50 doses to each cell line significantly enhanced radiation-induced cell killing. The enhancement ratio (ER) was obtained by dividing the radiation dose required to decrease the cell survival fraction to 37% (D0) by the dose to decrease cell survival to the same level when the cells were also treated with 5-FU. The ER in each of the cell lines was greater when they were incubated with 5-FU after radiation rather than prior to radiation. Longer exposure times with 5-FU resulted in enhanced radiation killing. The ER was significantly higher in the radioresistant cell line than in the radiosensitive line. These findings suggest that therapy with radiation and 5-FU may be of value as components of multidisciplinary treatment for biliary tract cancer. Protracted low dose exposure to 5-FU may prove to be most efficacious in enhancing the effects of radiation therapy.     

Mild form of beta-ketothiolase deficiency (mitochondrial acetoacetyl-CoA thiolase deficiency) in two Japanese siblings: identification of detectable residual activity and cross-reactive material in EB-transformed lymphocytes

Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency is an inherited metabolic disorder of isoleucine and ketone body catabolism. We report the cases of two siblings who showed clinically mild forms of this disorder. They did not excrete tiglylglycine in urine. Their EB-transformed lymphocytes contained residual T2 activity, which was confirmed by immunotitration analysis. In immunoblot analysis, the bands corresponding to T2 in the samples of the cell lines from two patients were the most intensely detected among those from 19 T2-deficient cell lines tested     

Two novel mutations in mitochondrial acetoacetyl-CoA thiolase deficiency

Summary We report a new patient with acetoacetyl-CoA thiolase deficiency in whom we found two new missense mutations.     

A case of metastatic pulmonary calcification after transient acute renal failure

We report a case of metastatic pulmonary calcification that appeared on high-resolution CT (HRCT) as multiple, lobular, ground-glass opacities sparing the perilobular area. Diffuse metastatic calcification such as that in our case was considered to be a result of postoperative transient acute renal failure. Decreasing alveolar air spaces due to both alveolar septal fibrosis and calcification caused the diffuse ground-glass opacities in the present case.