Pharmacological model for airway hypersensitivity produced by propranolol and reserpine in guinea pigs

Combined treatment with propranolol and reserpine enhanced acetylcholine-induced doseresponse curves for bronchoconstriction in guinea pigs in vivo. This airway hyperreactivity model was investigated pharmacologically. (1) Increased capillary permeability and increases in leukocytes in bronchoalveolar lavage fluid (BALF) were not observed after this combined treatment. (2) The increased airway sensitivity to acetylcholine produced by propranolol and reserpine was inhibited by ketotifen and theophylline, reported in clinical studies to inhibit airway hyperreactivity. (3) Two leukotriene (LT) receptor antagonists, MCI-826 and FPL-55712, clearly inhibited this increased airway reactivity. (4) A thromboxane A₂ (TXA₂) receptor antagonist, ONO-3708, and TXA₂ synthetase inhibitor, OKY-046, also inhibited this increased airway reactivity.These results suggest that the airway hyperreactivity model produced by propranolol and reserpine in guinea pigs is a valuable pharmacological tool for investigating a remedy and LT and TXA₂ may be involved in the onset of this airway hyperreactivity.     

Reorientation of Cortical Microtubules in the Sub-Apical Region during Tuberization in Single-Node Stem Segments of Potato in Culture

The initial events in tuberization were examined in single-nodestem segments of potato, in which the tuberization was easilyregulated in culture. The addition of 8% sucrose to the culturemedium caused the cessation of elongation of lateral shootsand the swelling of the sub-apical region of each shoot. Swellingwas first induced by lateral cell expansion, which was followedby periclinal cell division. The divided cells then expandedlaterally. The alteration in the direction of growth was accompaniedby the reorientation of arrays of cortical microtubules (MTs),which was monitored by immunofluorescence microscopy. Cellsin the sub-apical region of elongating shoots had prominenttransverse arrays of MTs. The MTs in swelling cells were orientedlongitudinally with respect to the axis of the shoot. Finally,the arrays of MTs became completely disorganized. By contrast,the elongation of lateral shoots continued in GA₃-treated segmentsand the cells in the sub-apical region of such shoots retainedconspicuous transverse arrays of MTs during culture, even inthe presence of a high concentration (8%) of sucrose. (Received July 2, 1994; Accepted May 19, 1995)     

Metabolism and Long-distance Translocation of Cytokinins

During plant development, distantly-located organs must communicate in order to adapt morphological and physiological features in response to environmental inputs. Among the recognized signaling molecules, a class of phytohormones known as the cytokinins functions as both local and long-distance regulatory signals for the coordination of plant development. This cytokinin-dependent communication system consists of orchestrated regulation of the metabolism, translocation, and signal transduction of this phytohormone class. Here, to gain insight into this elaborate signaling system, we summarize current models of biosynthesis, trans-membrane transport, and long-distance translocation of cytokinins in higher plants.     

Specific expression of Neu2 type B in mouse thymus and the existence of a membrane-bound form in COS cells

Neu2 mRNA from the mouse thymus, as we have reported [K. Kotani, A. Kuroiwa, T. Saito, Y. Matsuda, T. Koda, S. Kijimoto-Ochiai, Cloning, chromosomal mapping, and characteristic 5′-UTR sequence of murine cytosolic sialidase, Biochem. Biophys. Res. Commun. 286 (2001) 250-258], has a novel sequence at the 5′ terminus that shows the ability to encode 6 extra amino acids in the N-terminus than that of the muscle. In this paper, we analyzed the cDNA and EST database and found the five types of alternative splicing of Neu2 mRNA: A, B, C, D and N. We studied the expression of these types in the immune tissues and found that the thymus expressed only type B. We constructed 2 types of plasmid that encode long (B) or short (C) form of Neu2 protein, and transfected them into COS7 cells to study them under the same conditions. We found that 30-40% of the both forms of Neu2 activity was located in the crude membrane-fraction, and hydrolyzed ganglioside effectively, while both soluble fraction showed particular behavior with substrate specificity. Microscopic study by active staining with X-NANA showed that they located not only in the cytoplasm but also in areas surrounding the nucleus and in the peripheral ruffled spot.     

The role of thromboxane A2 [TxA2] in liver injury in mice

The role of thromboxane A2 (TxA2) in CCl4-induced liver disease was investigated in mice. Significant elevation of TxB2 in the liver was observed 6 hours after the injection of CCl4. Administration of OKY-046, a selective TxA2 synthetase inhibitor (10 and 50 mg/kg) and ONO-3708, a TxA2 receptor antagonist, (0.5, 1 and 2 mg/Kg) suppressed the elevation of serum GOT and GPT levels and histopathological changes of the liver. In addition, OKY-046 inhibited the elevation of TxB2 in the liver. When U-46619, a stable TxA2 mimetic was injected i.v. into the mice, clear elevation of serum GOT and GPT levels and histopathological score of the liver were observed. These results suggest that TxA2 play a role for the onset of CCl4-induced liver injury in mice.     

Risk Score to Predict 1-Year Mortality after Haemodialysis Initiation in Patients with Stage 5 Chronic Kidney Disease under Predialysis Nephrology Care

Background

Few risk scores are available for predicting mortality in chronic kidney disease (CKD) patients undergoing predialysis nephrology care. Here, we developed a risk score using predialysis nephrology practice data to predict 1-year mortality following the initiation of haemodialysis (HD) for CKD patients.

Methods

This was a multicenter cohort study involving CKD patients who started HD between April 2006 and March 2011 at 21 institutions with nephrology care services. Patients who had not received predialysis nephrology care at an estimated glomerular filtration rate (eGFR) of approximately 10 mL/min per 1.73 m² were excluded. Twenty-nine candidate predictors were selected, and the final model for 1-year mortality was developed via multivariate logistic regression and was internally validated by a bootstrapping technique.

Results

A total of 688 patients were enrolled, and 62 (9.0%) patients died within one year of HD initiation. The following variables were retained in the final model: eGFR, serum albumin, calcium, Charlson Comorbidity Index excluding diabetes and renal disease (modified CCI), performance status (PS), and usage of erythropoiesis-stimulating agent (ESA). Their β-coefficients were transformed into integer scores: three points were assigned to modified CCI≥3 and PS 3–4; two to calcium>8.5 mg/dL, modified CCI 1–2, and no use of ESA; and one to albumin<3.5 g/dL, eGFR>7 mL/min per 1.73 m², and PS 1–2. Predicted 1-year mortality risk was 2.5% (score 0–4), 5.5% (score 5–6), 15.2% (score 7–8), and 28.9% (score 9–12). The area under the receiver operating characteristic curve was 0.83 (95% confidence interval, 0.79–0.89).

Conclusions

We developed a simple 6-item risk score predicting 1-year mortality after the initiation of HD that might help nephrologists make a shared decision with patients and families regarding the initiation of HD.     

Who will desire upper airway stimulation as a treatment of obstructive sleep apnea in the Japanese patient population?

Sleep and Biological Rhythms -     

Presence of H type 3/4 chains of ABO histo-blood group system in serous cells of human submandibular gland and regulation of their expression by the secretor gene (FUT2).

We have investigated by immunochemistry the distribution of H Type 3/4 chains of the ABO histo-blood group system in human submandibular gland using a monoclonal anti-H MBr1 antibody specific for H Type 3/4 chains, and have found the expression of H Type 3/4 chains was mainly in the serous cells. Serous cells from secretors were stained by MBr1 but not by anti-A and anti-B antibodies, whereas serous cells from nonsecretors exhibited a negative reaction with MBr1. Mucous cells were not stained by MBr1. Only a few striated duct cells showed a weak reaction with anti-H MBr1. These results suggested that the H Type 3/4 chains were distributed predominantly in the serous cells of the human submandibular gland and that secretor Type alpha(1,2)fucosyltransferase (Se enzyme) controlled the synthesis of H Type 3/4 chains in vivo. Saliva also contained H Type 3/4 chains, which were controlled by the secretor gene (FUT2). The differences in the distributions of H Type 1, H Type 2, and H Type 3/4 chains of the ABO histo blood group system in the submandibular gland are discussed.     

Silymarin Induces Insulin Resistance through an Increase of Phosphatase and Tensin Homolog in Wistar Rats

Background and aims

Phosphatase and tensin homolog (PTEN) is a phosphoinositide phosphatase that regulates crucial cellular functions, including insulin signaling, lipid and glucose metabolism, as well as survival and apoptosis. Silymarin is the active ingredient in milk thistle and exerts numerous effects through the activation of PTEN. However, the effect of silymarin on the development of insulin resistance remains unknown.

Methods

Wistar rats fed fructose-rich chow or normal chow were administered oral silymarin to identify the development of insulin resistance using the homeostasis model assessment of insulin resistance and hyperinsulinemic- euglycemic clamping. Changes in PTEN expression in skeletal muscle and liver were compared using western blotting analysis. Further investigation was performed in L6 cells to check the expression of PTEN and insulin-related signals. PTEN deletion in L6 cells was achieved by small interfering ribonucleic acid transfection.

Results

Oral administration of silymarin at a dose of 200 mg/kg once daily induced insulin resistance in normal rats and enhanced insulin resistance in fructose-rich chow-fed rats. An increase of PTEN expression was observed in the skeletal muscle and liver of rats with insulin resistance. A decrease in the phosphorylation of Akt in L6 myotube cells, which was maintained in a high-glucose condition, was also observed. Treatment with silymarin aggravated high-glucose-induced insulin resistance. Deletion of PTEN in L6 cells reversed silymarin-induced impaired insulin signaling and glucose uptake.

Conclusions

Silymarin has the ability to disrupt insulin signaling through increased PTEN expression. Therefore, silymarin should be used carefully in type-2 diabetic patients.