In vitro release of immunoreactive atrial natriuretic peptide from the rat atria.

In vitro release of atrial natriuretic peptide (ANP) from atria was examined by ANP radioimmunoassay. Isolated right rat atria were incubated in Krebs-Ringer bicarbonate buffer, and test substances were added to the incubation medium. The fluid was assayed for rat ANP by a radioimmunoassay method recently developed in our laboratory. We produced an antiserum to human ANP(99-216) (alpha-hANP(1-28)) which showed a good cross-reactivity of 63% with rat ANP(99-126) (alpha-rANP(1-28)) and was useful for measuring rat ANP concentrations of the medium. Application of the medium to a reverse phase high performance liquid chromatography (HPLC) system resulted in a single peak of immunoreactive rat ANP corresponding to a small molecular weight synthetic rat ANP of 28 amino acid residues. Catecholamines (epinephrine, norepinephrine and isoproterenol) reduced the basal secretion of ANP, whereas acetylcholine stimulated the release of ANP. Forskolin and dibutyryl cyclic AMP did not affect the release of ANP. These results suggest the possibility that the regulation of ANP release may be partially associated with adrenergic and cholinergic mechanisms.</p

Improvement of the Efficacy of 5-aminolevulinic Acid-mediated Photodynamic Treatment in Human Oral Squamous Cell Carcinoma HSC-4

Ever since protoporphyrin IX (PpIX) was discovered to accumulate preferentially in cancer cells after 5-aminolevulinic acid (ALA) treatment, photodynamic treatment or therapy (PDT) has been developed as an exciting new treatment option for cancer patients. However, the level of PpIX accumulation in oral cancer is fairly low and insufficient for PDT. Ferrochelatase (FECH) and ATP-binding cassette transporter G2 (ABCG2) are known to regulate PpIX accumulation. In addition, serum enhances PpIX export by ABCG2. We investigated here whether and how inhibitors of FECH and ABCG2 and their combination could improve PpIX accumulation and PDT efficacy in an oral cancer cell line in serum-containing medium. ABCG2 inhibitor and the combination of ABCG2 and FECH inhibitors increased PpIX in the presence of fetal bovine serum (FBS) in an oral cancer cell line. Analysis of ABCG2 gene silencing also revealed the involvement of ABCG2 in the regulation of PpIX accumulation. Inhibitors of FECH and ABCG2, and their combination increased the efficiency of ALA-PDT even in the presence of FBS. ALA-PDT-induced cell death was accompanied by apoptotic events and lipid peroxidation. These results suggest that accumulation of PpIX is determined by the activities of ABCG2 and FECH and that treatment with a combination of their inhibitors improves the efficacy of PDT for oral cancer, especially in the presence of serum

Flow Cytometric Analysis of Ca2+-Induced Membrane Permeability Transition of Isolated Rat Liver Mitochondria

The membrane permeability transition (MPT) of mitochondria plays an important role in the mechanism of apoptotic cell death in various cells. Classic type MPT is induced by Ca2+ in the presence of inorganic phosphate and respiratory substrate, and is characterized by various events including generation of reactive oxygen species (ROS), membrane depolarization, swelling, release of Ca2+ and high sensitivity to cyclosporine A. However, the sequence of these events and the effect of antioxidants on their events remain obscure. Flow cytometry is a convenient method to investigate the order of events among various functions occurring in MPT using a limited amount of mitochondria (200 µl of 0.02 mg protein/ml) without contamination by other organelles. Flow cytometric analysis revealed that Ca2+ sequentially induced ROS generation, depolarization, swelling and Ca2+ release in mitochondria by a cyclosporine A-inhibitable mechanism. These results were supported by the finding that Ca2+-induced MPT was inhibited by antioxidants, such as glutathione and N-acetylcysteine. It was also revealed that various inhibitors of Ca2+-induced phospholipase A2 suppressed all of the events associated with Ca2+-induced MPT. These results suggested that ROS generation and phospholipase A2 activation by Ca2+ underlie the mechanism of the initiation of MPT

alpha-lipoic acid suppresses 6-hydroxydoparnine-induced ROS generation and apoptosis through the stimulation of glutathione synthesis but not by the expression of heme oxygenase-1

We previously reported that the generation of reactive oxygen species (ROS) is the initial event in cell death induced by 6-hydroxydopamine (6-OHDA), an experimental model of Parkinsonism. Since recent studies suggested the important role of antioxidant activity of alpha-lipoic acid (LA) in the suppression of apoptosis of various types, we studied the effect on 6-OHDA-induced apoptosis of PC12 cells. Biochemical analysis revealed that LA suppressed the 6-OHDA-induced ROS generation, increase of caspase-like activity and chromatin condensation. The suppression of 6-OHDA-induced apoptosis by LA required pre-incubation of PC12 cells with LA for 12-24 h. LA increased the intracellular levels of heme oxygenase-1 (HO-1) and glutathione (GSH) and stimulated the expression of GSH synthesis-related genes such as cystine/glutamate antiporter and gamma-glutamylcysteine synthetase (gamma-GCS). However, Sn-mesoporphyrin IX, an inhibitor of HO-1, did not attenuate the LA-induced suppression of apoptosis. In contrast, buthionine sulfoximine, an inhibitor of gamma-GCS, attenuated the LA-induced suppression of ROS generation and chromatin condensation. in addition, a transcription factor Nrf2, which regulates the expression of antioxidant enzymes such as gamma-GCS, translocated to the nucleus by LA. These results suggested that LA suppressed the 6-OHDA induced-apoptosis by the increase in cellular glutathione through stimulation of the GSH synthesis system but not by the expression of HO-1.</p

Paraganglioma that caused sinus arrest

Paragangliomas are neural-crest-derived nonepithelial neuroendocrine tumors distributed along the parasympathetic and sympathetic nerves. To our knowledge, no studies were reported regarding sinus arrest on day 4 after paraganglioma resection. A 66-year-old female patient with a history of pulmonary vein isolation visited our department for sigmoid colon cancer treatment. Enhanced computed tomography revealed an enhanced small nodule-like lymph node near the root of the inferior mesenteric artery. The patient underwent laparoscopic colectomy with regional lymph node dissection. Postoperatively, paroxysmal atrial fibrillation attacks developed, and the patient resumed oral medication. Additionally, sinus arrest after tachycardia developed. Changing the oral medication could maintain her circulatory dynamics. Pathological examination revealed that differentiated tubular adenocarcinoma infiltrated the submucosa. Immunohistochemically, the excised nodule as a lymph node was considered a functional paraganglioma. Our case indicates that paraganglioma resection and oral medication resumption may contribute to sinus arrest. When arrhythmias affecting the circulation occur perioperatively, the presence of a catecholamine-producing tumor should be considered in addition to cardiac disease

The Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT): Study Design and Participants

Background: Lifestyle and life-environment factors have undergone drastic changes in Japan over the last few decades. Further, many molecular epidemiologic studies have reported that genetic, epigenetic, and other biomarker information may be useful in predicting individual disease risk.Methods: The Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT) was launched in 2011 to identify risk factors for lifestyle-related disease, elucidate factors that extend healthy life expectancy, and contribute toward personalized healthcare based on our more than 20 years’ experience with the JPHC Study. From 2011 through 2016, a baseline survey was conducted at 16 municipalities in seven prefectures across the country. A self-administered questionnaire was distributed to all registered residents aged 40–74, which mainly asked about lifestyle factors, such as socio-demographic situation, personal medical history, smoking, alcohol and dietary habits. We obtained informed consent from each participant to participate in this long follow-up study of at least 20 years, including consent to the potential use of their residence registry, medical records, medical fee receipts, care insurance etc., and to the provision of biospecimens (blood and urine), including genomic analysis.Results: As of December 31, 2016, we have established a population-based cohort of 115,385 persons (Response rate 44.1%), among whom 55,278 (47.9% of participants) have provided blood and urine samples. The participation rate was slightly higher among females and in the older age group.Conclusion: We have established a large-scale population-based cohort for next-generation epidemiological study in Japan