Effects of sorbitol and lactate on erythropoietin production in HepG2 cells.

Promotion of erythropoietin (EPO) production is important for erythropoiesis as well as cell viability. The most effective inducing factor for EPO production is hypoxia. Hypoxia inducible factor (HIF), a regulator of EPO production, is increased under hypoxic conditions and is also affected by various regulators such as sirtuin1 (SIRT1). SIRT1 is regulated by the cytoplasmic redox state, which is thought to affect EPO production. Therefore, we investigated the effects of sorbitol and lactic acid, which serve as substrates for cellular respiration and bring cells into a reduced state, on EPO production in HepG2 cells. The addition of low-concentration sorbitol to HepG2 cells produced a mildly reduced state similar to that of hypoxia and increased NAD+, SIRT1, and HIF-α, and EPO mRNA expression. On the other hand, lactate suppressed EPO mRNA expression at all concentrations. Inhibition of lactate production from pyruvate abolished the effect of low sorbitol concentrations on EPO mRNA expression. When low-concentration sorbitol and a reducing agent were administered simultaneously, the effect of increasing EPO mRNA expression disappeared. It was suggested that SIRT1 and EPO production increased under conditions where lactate production was not suppressed, even under mildly reduced conditions similar to hypoxia.

Factors predictive of survival after percutaneous endoscopic gastrostomy in the elderly: is dementia really a risk factor?

OBJECTIVES: Outcomes, especially survival, after percutaneous endoscopic gastrostomy (PEG) in patients with dementia remain unclear. The aims of this study were to assess the impact of dementia on survival after PEG and to explore the risk factors in elderly patients. METHODS: A total of 311 consecutive Japanese patients who underwent PEG were enrolled in this retrospective cohort study. Dementia was defined according to the standard criteria. After the clinical characteristics of patients with and without dementia were compared, the Kaplan-Meier method and Cox proportional-hazards regression analysis were applied to analyze survival rates. RESULTS: Survival was not significantly different between the two groups. The 12-month survival rate of patients with dementia (N = 143) was 51%, and that of patients without dementia (N = 168) was 49%. More than 20% of patients with dementia lived more than 3 yr after PEG. The predictors of poor survival after PEG were previous subtotal gastrectomy (odds ratio [OR] 2.619, 95% confidence interval [CI] 1.367-5.019), serum albumin <2.8 g/dL (OR 2.081, 95% CI 1.490-2.905), age >80 yr (OR 1.721, 95% CI 1.234-2.399), chronic heart failure (OR 1.541, 95% CI 1.096-2.168), and male gender (OR 1.407, 95% CI 1.037-1.909). CONCLUSIONS: In our series, there was no evidence to support a poorer prognosis after PEG in elderly people with dementia compared with the cognitively preserved elderly. However, if patients are male or of advanced age, have a low serum albumin, chronic heart failure, or subtotal gastrectomy, physicians should inform families that a poor prognosis is expected before performing PEG.

A new technique for muscle flap closure of the empyema space in complicated chronic bronchopleural fistula. Wedging the causative bronchus with a plug.

OBJECTIVES: It is difficult to close the empyema space once it is opened, especially in cases complicated with a chronic bronchopleural fistula. A muscle flap closure is generally employed to prevent this situation. However, this operation occasionally fails because the space newly recurs around the fistula due to atrophic change occurring in these translocated muscles. The aim of the present new technique was to prevent inspiratory pressure from the inside of the bronchus by bronchial emboli, and help the adhesion between the fistula stump and the muscle flap, even if they have become atrophic and no longer have sufficient volume to fill the entire empyema space. METHODS: We carried out fiberscopic embolism of causative bronchioles followed by muscle flap closure in 4 patients in whom open drainage had already been performed against parapneumonic empyema within the bronchial fistula. The bronchial fistula was plugged from the inside of the bronchus by silicon material, and stainless steel wire was used to connect this plug tightly to the muscle flaps, so that the fistula was sandwiched between them. In all cases, we succeeded in complete closure of the bronchial fistula and empyema space without using the omentum, and there has been no recurrence. CONCLUSION: The presented new technique was beneficial for achieving muscle flap closure of the empyema space with a chronic bronchopleural fistula.