Increased insulin sensitivity and hypoinsulinemia in APS knockout mice

A tyrosine kinase adaptor protein containing pleckstrin homology and SH2 domains (APS) is rapidly and strongly tyrosine phosphorylated by insulin receptor kinase upon insulin stimulation. The function of APS in insulin signaling has heretofore remained unknown. APS-deficient (APS(-/-)) mice were used to investigate its function in vivo. The blood glucose-lowering effect of insulin, as assessed by the intraperitoneal insulin tolerance test, was increased in APS(-/-) mice. Plasma insulin levels during fasting and in the intraperitoneal glucose tolerance test were lower in APS(-/-) mice. APS(-/-) mice showed an increase in the whole-body glucose infusion rate as assessed by the hyperinsulinemic-euglycemic clamp test. These findings indicated that APS(-/-) mice exhibited increased sensitivity to insulin. However, overexpression of wild-type or dominant-negative APS in 3T3L1 adipocytes did not affect insulin receptor numbers, phosphorylations of insulin receptor, insulin receptor substrate-1, or Akt and mitogen-activated protein kinase. The glucose uptake and GLUT4 translocation were not affected by insulin stimulation in these cells. Nevertheless, the insulin-stimulated glucose transport in isolated adipocytes of APS(-/-) mice was increased over that of APS(+/+) mice. APS(-/-) mice also showed increased serum levels of leptin and adiponectin, which might explain the increased insulin sensitivity of adipocytes.     

Inhibition of Autophagy by 3-MA Enhances the Effect of 5-FU-Induced Apoptosis in Colon Cancer Cells

Background  5-fluorouracil-(5-FU)-based adjuvant chemotherapy is widely used for the treatment of colorectal cancer. However, 5-FU resistance in the course of treatment has become more common. Therefore, new therapeutic strategies and/or new adjuvant drugs still need to be explored. Methods  Two colon-cancer-derived cell lines, colon26 and HT29, were used to investigate the effect of 5-FU, 3-methyladenine (3-MA, an autophagy inhibitor), or their combination on apoptotic cell death and autophagy. MTT assay, Hochest plus propidium iodide (PI) staining, and DNA fragmentation assay were used to observe apoptosis. Meanwhile, monodansylcadaverine (MDC) was used to detect autophagy. Finally, immunoblotting assay was used to explore the molecular change that occurred. Results  We observed the apoptosis induced by 5-FU in colon cancer cells. Meanwhile, autophagy was also stimulated. The combination treatment of 3-MA and 5-FU significantly increased the apoptotic cell death. By isolating the subcellular fractions of mitochondria and cytosol, we observed that the release of cytochrome c was increased in combination-treated cells. Cytochrome c resulted in the activation of caspase-3, thus activating PARP. Moreover, the anti-apoptotic protein, Bcl-xL, was significantly downregulated by 3-MA. Conclusions  Our results suggest that 5-FU-induced apoptosis in colon cancer cells can be enhanced by the inhibitor of autophagy, 3-MA. Autophagy might play a role as a self-defense mechanism in 5-FU-treated colon cancer cells, and its inhibition could be a promising strategy for the adjuvant chemotherapy of colon cancer.     

Estimated Glomerular Filtration Rate —A More Stable Indicator than Creatinine Clearance in Peritoneal Dialysis Practice

Objective: The usefulness of estimated glomerular filtration rate may not be restricted to pre-dialysis patients, since we reported that estimated glomerular filtration rate was well correlated with measured total creatinine clearance in peritoneal dialysis patients. To clarify the clinical usefulness of estimated glomerular filtration rate as a parameter for peritoneal dialysis adequacy, we retrospectively surveyed estimated glomerular filtration rate and total creatinine clearance in peritoneal dialysis patients treated at JA Toride Medical Center.Patients and Methods: A total of 114 data sets of estimated glomerular filtration rate and total creatinine clearance from 21 PD patients treated at JA Toride Medical Center were collected from November 2010 to October 2011. The patients consisted of 15 men and six women with an average age of 66.6 ± 12.6 years (46–95 years old). The average number of samples was 5.4 ± 1.5 (2 to 7) per patient.Results: The collected data showed less correlation of estimated glomerular filtration rate and total creatinine clearance (r. = 0.435) than that of a previous cross-sectional study (r. = 0.836). As reported in pre-dialysis patients, the differences between estimated glomerular filtration rate and total creatinine clearance were correlated with total creatinine excretion in urine and PD effluent (r. = 0.821). The differences were also correlated with normalized protein catabolic rate, which was one of the main determinant factors for total creatinine excretion (r. = 0.636). A similar tendency was apparently observed in one patient with poor compliance to diet therapy and fluctuating dietary intake. From the analysis of these data, serum creatinine seemed to fluctuate less possibly due to compensatory capacity of the residual renal function in small solute clearance.Conclusions: Consequently, estimated glomerular filtration rate was turned out to be a more stable parameter than total creatinine clearance, which might be a desirable feature in long-term follow-up of peritoneal dialysis patients.     

Occupational Factors and Problem Drinking among a Japanese Working Population

Problem drinking is a serious public health problem in the workplace. However, few Japanese epidemiological studies have investigated the occupational characteristics of problem drinking. The purpose of this study is to clarify the occupational risk factors for problem drinking among a Japanese working population. We used data from a random-sampling survey about mental health and suicide, conducted among Hamamatsu City residents aged 15 to 79 yr old during May and June in 2008. The relation between occupational factors and problem drinking was analyzed with multiple logistic regression models stratified by gender. CAGE questionnaire was used to assess problem drinking. With regard to employment types, problem drinkers were more prevalent among self-employed women. With regard to occupational types, clerical and service professions had more problem drinkers of either sex, while administrative/managerial and sales professions had more women with such problem. With regard to company size, male problem drinkers were more prevalent in smaller companies than in larger ones. These results indicate that the prevalence of problem drinkers in the workplace depends on where one works. It is necessary to consider these characteristics to provide effective measures to address problem drinking in the workplace.     

Echographic detection of diethylnitrosamine-induced liver tumors in rats and the effect of the intratumoral injection of an inhibitor of c-Jun N-terminal kinase

Background and Aim:  There have so far been few reports describing echographic studies of chemically-induced carcinogenesis in rodent livers. Using echography, we observed diethylnitrosamine-induced liver tumors in rats and examined the effect of an intratumoral injection of an inhibitor of c-Jun N-terminal kinase.
Methods:  Male Wistar rats were given 100 ppm of diethylnitrosamine for 6 weeks and their liver nodules were examined by echography weekly. The size of the nodules was measured and they were examined histologically. The effect of SP600125, an inhibitor of c-Jun N-terminal kinase, on the growth of rat hepatoma cell line McA-RH7777 was tested in vitro . Thereafter, SP600125 was injected into the liver nodules under echographic guidance in vivo and the changes in the proliferating cell nuclear antigen expression and size of the nodules were examined.
Results:  The four distinct lobes of rat livers were clearly observed by transabdominal echography. The nodules in the livers were first detected 6 weeks after the treatment began, when they were as small as 1.6 mm in diameter. The nodules thereafter became more malignant histologically as they grew larger than 4 mm. SP600125 decreased the expression of proliferating cell nuclear antigen and the growth of McA-RH7777 cells. After SP600125 was injected in vivo , the proliferating cell nuclear antigen level and the growth rate of the rat liver nodules all significantly decreased.
Conclusions:  Our results indicate that echography is quite useful for follow-up studies of liver carcinogenesis in rats, and c-Jun N-terminal kinase might be another therapeutic target in liver neoplasms.     

Comparison of the clinical courses of the opticospinal and conventional forms of multiple sclerosis in Japan

We evaluated the clinical courses of 216 patients with multiple sclerosis (MS) diagnosed according to the recommended diagnostic criteria of McDonald et al (10). Sixty-five patients clinically displaying selective involvement of the optic nerves and spinal cord were classified as opticospinal MS (OS-MS), while the other 151 showing disseminated involvement of the central nervous system were classified as conventional MS (C-MS). The disease duration did not differ significantly between the two subtypes (11.2 years vs. 11.5 years). In addition to a higher age of onset, female preponderance and higher Kurtzke's expanded disability status scale (EDSS) scores, the OS-MS patients showed a markedly lower frequency of secondary progressive MS than the C-MS patients (4.6% vs. 29.1%, p=0.0001). The EDSS scores of the C-MS patients were significantly correlated with the disease duration, while those of the OS-MS patients were not. Among the C-MS patients, the frequency of secondary progressive MS was significantly more common in patients with a disease duration of more than 10 years than in those with a shorter duration. These results suggest that the irreversible disability in OS-MS is determined by relapses, rather than by chronic progression, whereas C-MS has a similar clinical course to MS in Westerners.     

Myasthenia gravis after allogeneic bone marrow transplantation treated with mycophenolate mofetil monitored by peripheral blood OX40+ CD4+ T cells

A patient who developed myasthenia gravis (MG) 25 months after allogeneic bone marrow transplant was immunologically analyzed. OX40+CD4+ T cells in the peripheral blood prominently increased one month before the onset of MG. CD4/CD8 ratios, usually abnormally inverted in patients with chronic graft-vs.-host disease (cGVHD), showed pseudonormalization during the course of MG. We succeeded in uneventful rapid tapering of prednisolone (PSL) using mycophenolate mofetil (MMF). Monitoring of OX40+CD4+ T cells supported the tapering of PSL and MMF as a marker of cGVHD activity. This case suggested the utility of MMF and monitoring of OX40+CD4+ T cells in the management of cGVHD-associated autoimmune diseases.     

Mitochondrial K<Subscript>ATP</Subscript> channel-dependent and -independent phases of ischemic preconditioning against myocardial infarction in the rat

To obtain insight into the role of the mitochondrial ATP-sensitive K(+) (mitoK(ATP)) channel in ischemic preconditioning (PC), we aimed to clarify the mitoK(ATP) channel-dependent phase of PC in two PC protocols with different intervals between PC ischemia and an index ischemia. The possible contribution of mitoK(ATP) channel opening to protein kinase C activation in PC was also examined by Western blotting. Myocardial infarction was induced by 30-min coronary occlusion/2-h reperfusion in rat hearts in situ, and infarct size was expressed as a percentage of the area at risk (% IS/AR). PC was performed with 2 episodes of 5-min ischemia, and each heart was subjected to 30-min ischemia either 5 min or 20 min after PC. At 5 min after PC, both PKC-delta and -epsilon were translocated and the myocardium was protected against infarction (% IS/AR = 28.3 +/- 2.7 % vs. 72.7 +/- 2.2 in controls p < 0.05). Pretreatment with a selective mitoK(ATP) channel blocker, 5-hydroxydecanoate (5-HD, 10 mg/kg), abolished the cardioprotection but not PKC translocation by PC. At 20 min after PC, PKC translocation remained at the same level as that 5 min after PC, but the anti-infarct tolerance was attenuated (%IS/AR = 43.5 +/- 4.7 %). Injection of 5-HD after PC did not affect anti-infarct tolerance at 5 min after PC but abolished the protection at 20 min after PC without any effects on PKC. These results suggest that the mitoK(ATP) channel plays a role in triggering of PC in a PKC-independent manner and that the role of the mitoK(ATP) channel as a mediator of protection is detectable after, but not before, the PC effect starts to decay without a change in the level of PKC translocation in the rat heart.