Stimulation by polyols of the two ryanodine receptor isoforms of frog skeletal muscle

While the stimulating effect of concentrated salts on ryanodine receptor (RyR) is widely accepted in Ca2+-induced Ca2+ release (CICR) and [3H]ryanodine binding, the effect of non-ionic solutes on RyR is controversial. We investigated the effects of polyols on [3H]ryanodine binding to α- and β-RyR purified from bullfrog skeletal muscle, and on CICR from sarcoplasmic reticulum (SR) in a skinned frog skeletal muscle fibre. Addition of polyols (glucose, sucrose, sorbitol, glycerol and ethylene glycol) in submolar to molar concentrations to an isotonic salt medium increased dose-dependently Ca2+-activated [3H]ryanodine binding to α- and β-RyR of a similar magnitude. The increase is due to the rise in both apparent affinity (1/KD) and maximal numbers of binding sites (Bmax) for ryanodine. In addition to this stimulating effect, glucose sensitized both isoforms to Ca2+ in the Ca2+-activated reaction, which is distinct in mechanism(s) from caffeine. These stimulating effects of polyols were not observed unless some NaCl was present, which might explain the discrepancy among reported results. Consistent with these findings, polyols reversibly enhanced the rate of CICR from SR in skinned fibres with an increase in the Ca2+ sensitivity. The enhanced CICR was still sensitive to well-known modulators for CICR (Ca2+, Mg2+, adenine nucleotides and procaine), as with [3H]ryanodine binding. The results of this study reveal that polyols stimulate α- and β-RyR in frog skeletal muscle, bringing about increased CICR activity. The finding that the specific activity of polyols in stimulation of [3H]ryanodine binding was approximately proportional to their molecular weights leads us to discuss the possible modification of protein surface--water molecule interaction as an underlying mechanismThis revised version was published online in July 2005 with corrections to the Cover Date.     

Diagnosis of Small Pancreatic Carcinoma

A retrospective analysis was performed to evaluate the clinicalsymptoms and abnormal test findings in small pancreatic carcinoma.Five hundred and thirty-six cases of pancreatic carcinoma withthe histology of duct cell carcinoma were collected from 14medical centers in Japan. In 440 of the cases, tumor size wasmeasured at the time of laparotomy or from the resected specimen.Three hundred and seventy-seven patients (86%) had a carcinomalarger than 3.0 cm; only 30% of these were resectable. Sixty-threepatients (14%) had a carcinoma of 3.0 cm or less, with resectabilityof 97%. Detecting a tumor of "3 cm or less" with a high probabilityof resectability is the objective of early diagnosis with theresulting possibility of a cure. In most cases these small carcinomaswere found easily when obstructive jaundice was present (73%).However, the estimated occurrence of obstructive jaundice associatedwith carcinomas of 3 cm or less was only 10% among the totalcases of pancreatic carcinoma studied. Therefore, it is necessaryfor early diagnosis to detect carcinomas of 3 cm or less presentingwithout jaundice. The symptoms of small carcinoma without jaundiceare weight loss, anorexia, upper abdominal pain, back pain anda palpable abdominal mass. Among the various available examinations,endoscopic retrograde cholangiopancreatography, computerizedtomography and ultrasonography were valuable in diagnosing thesesmall carcinomas.     

Changes in Cell Characteristics Due to Culture Conditions in Cell Lines From Human Small Cell Lung Cancer

Eight cultured cell lines were established from human smallcell lung cancers. Every cell line showed the morphologicaland biochemical characteristics of small cell cancer. Changesin cell characteristics were observed in many of these celllines when culture conditions were changed: "oat cell type"changed to "intermediate cell type" and vice versa when serum-freemedium was changed to serum-supplemented medium; a deficiencyof vitamin A in the medium caused a change to squamous cellsand vice versa; and a tumor promoter (teleocidin B) enhancedthe adherence of these cells to the surface of plastic culturedishes. These findings provide evidence that many small celllung cancer cell lines can change their morphology with changesin the environment of the cells.     

EFFECTS OF SEED SAPONINS OF THEA SINENSIS L. (RYOKUCHA SAPONIN) ON ALCOHOL ABSORPTION AND METABOLISM

We evaluated the effects of the seed saponins of Thea sinensisL. on alcohol absorption and metabolism in rats and mice. Anethanolic extract from the seeds of T. sinensis was orally administeredto the rats 1 hr before or 0.5 hr after administration of ethanol(2 g/kg), and the blood ethanol assayed 0.5, 1, 2, 3, and 4hr after ethanol administration. The ethanol level decreasedafter both pie- and post- administration of the extract. Theextract was further purified to obtain a saponin fraction whichwas orally administered to mice 1 hr before ethanol administration.Blood, liver, and stomach were obtained 0, 1, 3, and 6 hr afterethanol administration, and the ethanol, acetaldehyde, acetate,and acetone concentrations in each specimen were measured byhead space gas chromatography. The saponin fraction decreasedthe ethanol levels in the blood and liver but increased thatin the stomach five-fold over the control level, suggestinginhibition of alcohol absorption. The ethanol disappearancetime from the blood was shortened, suggesting the promotionof alcohol disappearance. The acetate and acetone levels wereunaffected. However, the acetaldehyde level decreased in theblood, liver, and stomach. The decreases in the ethanol andacetaldhyde levels in the liver suggested the protective effectsof the seed saponins on the liver. The saponins did not directlyinhibit hepalic alcohol dehydrogenase activity. The seed saponinsof T. sinensis seem to suppress alcohol absorption by slowinggastric emptying and by inhibiting absorption across the cellmembranes of the digestive tract.     

Reflex sympathetic dystrophy in childhood: A case report

A case report is presented of a 15-year-old girl with reflex sympathetic dystrophy (RSD). She was referred to hospital because of left upper limb pain. Her left upper limb was cold, edematous and blue with a limited active range of movement. The serum concentration of noradrenaline was lower on the painful side than on the healthy side, and neurotropin, which has an antinociceptive effect to hyperalgesia, was clearly effective. Early diagnosis and management is essential in the treatment of RSD and administration of neurotropin is a useful and non-invasive treatment without severe adverse effects.     

A sensitive sandwich ELISA for measuring thrombopoietin in human serum: serum thrombopoietin levels in healthy volunteers and in patients with haemopoietic disorders

A sensitive sandwich enzyme-linked immunosorbent assay (ELISA) has been established to estimate serum thrombopoietin (TPO) concentrations in healthy volunteers and patients with haemopoietic disorders. The ELISA uses a mouse monoclonal antibody (Ab) as the capture Ab and a biotinylated rabbit polyclonal Ab as the detector. The ELISA was reproducible, highly sensitive and specific for human TPO. The coefficients of intra- and inter-assay variation were from 3.0% to 4.9% and from 5.9% to 6.1%, respectively. The quantitative limit of the ELISA was 0.09 fmol/ml in serum. The quantitative limit was lower than the normal level. The dose–response curves of serum samples from healthy volunteers and patients with haemopoietic disorders were parallel to the standard curves. The ELISA did not cross-react with a variety of blood components and cytokines to produce false-positive results.
The serum TPO concentrations from 29 normal males and 21 females were 0.79 ± 0.35 and 0.70 ± 0.26 fmol/ml, respectively. Serum TPO levels in patients with aplastic anaemia (AA), acute lymphocytic leukaemia (ALL) and essential thrombocythaemia (ET) were measured using the ELISA. The serum TPO levels in the patients with ET ( n  = 6, 2.80 ± 1.55 fmol/ml) were higher than the normal level. The patients with AA ( n  = 7, 18.53 ± 12.37 fmol/ml) and ALL ( n  = 5, 10.36 ± 5.57 fmol/ml) had significantly higher serum TPO levels than normal individuals. These results indicate that the ELISA specific to TPO should prove useful in measuring the TPO concentration in serum samples.     

Regulation of intracellular metabolism by biodegradable polyrotaxanes

Cellular response to our designed biodegradable polyrotaxanes was investigated in terms of changes in cytoplasmic calcium levels in platelets. The polyrotaxanes regulated thrombin-induced calcium increase in platelets although constituent molecules of the polyrotaxanes showed fewer effects on the intracellular metabolism. Further, an increase in membrane fluidity of red blood cell ghosts was significantly observed by the addition of the polyrotaxanes. Static light scattering study revealed that the polyrotaxanes formed a supramolecular association state in relation to the molecular weight of PEG: a loosely packed association with a specific molecular shape. From these characteristics, it is suggested that supramolecular level interactions between the polyrotaxanes and cell membranes regulate the intracellular metabolism. It is concluded that these biodegradable polyrotaxanes can be feasible as temporarily-controlled bioactivator.     

Studies on Duodenal Cyclic AMP Content in Pancreatic Disease after Administration of Pancreozymin and Secretin

Cyclic AMP (cAMP) output in the duodenal contents of 11 normal subjects, 18 patients with chronic pancreatitis, six convalescing from acute pancreatitis and five with pancreatic carcinoma was measured after a single dose of pancreozymin and secretin. The technic was indirect, utilizing recovery of duodenal contents by the Dreiling tube rather than direct measurements of fluid that was not contaminated by bile. In all patients groups, cAMP output reached a peak after this stimulation with a concomitant increase of bicarbonate and amylase outputs. A significantly decreased cAMP output was observed in all pancreatic disease groups compared to the normal group. Patients with chronic pancreatitis showed a slightly decreased cAMP output, considerably decreased bicarbonate output and normal amylase output. In acute pancreatitis cAMP output was reduced with normal bicarbonate and amylase outputs. In pancreatic carcinoma cAMP decreased significantly, bicarbonate output was moderately reduced and amylase output was normal. cAMP output in all groups studied did not correlate with either bicarbonate output or amylase output.