Effects of estrogen on action potential and membrane currents in guinea pig ventricular myocytes

To explore a possible ionic basis for the prolonged Q-T interval in women compared with that in men, we investigated the electrophysiological effects of estrogen in isolated guinea pig ventricular myocytes. Action potentials and membrane currents were recorded using the whole cell configuration of the patch-clamp technique. Application of 17beta-estradiol (10-30 microM) significantly prolonged the action potential duration (APD) at 20% (APD(20)) and 90% repolarization (APD(90)) at stimulation rates of 0. 1-2.0 Hz. In the presence of 30 microM 17beta-estradiol, APD(20) and APD(90) at 0.1 Hz were prolonged by 46.2 +/- 17.1 and 63.4 +/- 11.7% of the control (n = 5), respectively. In the presence of 30 microM 17beta-estradiol the peak inward Ca(2+) current (I(CaL)) was decreased to 80.1 +/- 2.5% of the control (n = 4) without a shift in its voltage dependence. Application of 30 microM 17beta-estradiol decreased the rapidly activating component of the delayed outward K(+) current (I(Kr)) to 63.4 +/- 8% and the slowly activating component (I(Ks)) to 65.8 +/- 8.7% with respect to the control; the inward rectifier K(+) current was barely affected. The results suggest that 17beta-estradiol prolonged APD mainly by inhibiting the I(K) components I(Kr) and I(Ks).

Effects of arginine-vasopressin fragment 4-9 on rodent cholinergic systems

Arginine-vasopressin fragment 4-9 (AVP4-9) has been demonstrated in animal studies to facilitate learning and memory. To clarify the mechanisms of this facilitation, we focused on the effects of AVP4-9 on rodent cholinergic systems. AVP4-9 (0.1 microM) enhanced the basal and the high-potassium-evoked acetylcholine (ACh) release from rat hippocampal slices (122.4 and 120.0% of control, respectively) in the presence of 1.3 mM calcium (physiological level) at 60 min after the incubation at 37 degrees C. The AVP4-9-stimulated basal ACh release was inhibited by a V1-selective antagonist ([(beta-mercapto-beta,beta-cyclopentamethylene propionic acid)1, O-methyl-Tyr2, Arg8] vasopressin), but not by a V2-selective antagonist ([adamantaneacetyl1, O-ethyl-D-Tyr2, Val4, aminobutyryl6, Arg8,9]-vasopressin). In addition, AVP4-9 did not affect the basal ACh release under the calcium-free condition at 37 degrees C or in the presence of 1.3 mM calcium at 4 degrees C. However, AVP4-9 facilitated the passive-avoidance response of scopolamine (a cholinergic blocker)-induced memory-deficient mice. These findings demonstrate that AVP4-9 stimulates ACh release via mediation by V1-like vasopressin receptors, and shows dependence on calcium ion and temperature. The results also suggest that the mechanism of the facilitative effects of AVP4-9 on learning and memory consist of the observed stimulation of cholinergic systems and other parallel pathways that would not be inhibited by cholinergic blocking.

Butyltin residues in livers of humans and wild terrestrial mammals and in plastic products

Butyltin compounds (BTs) including mono-(MBT), di-(DBT) and tributyltin (TBT) were determined in livers of humans and wild terrestrial mammals, such as raccoon dogs (Nyctereutes procyonoids) and monkeys (Macaca fuscata) from Japan. In addition, 22 samples of plastic products were analyzed. BT residues were detected in all the liver samples of humans and raccoon dogs, with concentrations of <360 ng/g wet wt, whereas concentrations in the liver of monkeys were either less than the detection limit or were only in trace levels. Elevated concentrations of BTs, particularly DBT (<140,000 ng/g) and MBT (<130,000 ng/g), were found in some plastic products, such as baking parchments made from siliconized paper and gloves made up from polyurethane. The results of a cooking test using the above baking parchment indicated the transfer of BTs to foodstuffs. These observations suggest expansion of BT contamination among terrestrial mammals. BT pollution from industrial appliances, such as plastic stabilizers and catalysts other than those of marine origin as antifouling agents, are suggested as alternative sources of exposure.

Distribution and specific bioaccumulation of butyltin compounds in a marine ecosystem

Butyltin compounds (BTs), including tributyltin (TBT) and its breakdown products, di- (DBT) and monobutyltin (MBT), were determined in sea water, sediment, and biota at various trophic levels in the food chain collected from Otsuchi Bay, Japan, for understanding distribution and bioaccumulation of BTs in natural marine ecosystems. BT residues were detected in all the compartments analyzed, although their concentrations appeared to be less than those in polluted areas. Concentrations of BTs in sea water were higher in locations near Otsuchi Port, indicating that maritime activities in the harbor has been a major source of BTs in this bay. A specific peak in BT residue levels was found in sediment cores at an estimated depth that dated to be from the 1980s. Lack of significant variation in the composition of BTs at different depths of cores suggests slow degradation rate of these compounds in sediments. BTs were accumulated in plankton and other organisms up to approximately 70,000 times higher than in sea water. However, no considerable biomagnification was observed for BTs through the food chain. Relatively high concentrations were found in caprellids and smaller fish, such as gunnels. These organisms accumulated TBT as the predominant compound among BT derivatives and showed higher bioconcentration factors for TBT than in other species reported so far. Our results suggest that certain organisms in the food chain may have a less capacity to degrade TBT, and therefore may accumulate BTs at elevated levels.http://link.springer-ny. com/link/service/journals/00244/bibs/37n1p50.html

Screening for aetiology of thrombophilia: a high prevalence of protein S abnormality

We systematically screened for the aetiology of thrombophilia in 115 patients with venous, arterial and small vessel thromboses. Forty-one patients (36% of those we examined) suffering from a variety of thromboses, including deep vein thrombosis, pulmonary embolism, arterial occlusion, cerebral infarction, Moyamoya disease and ulcerative colitis, were characterized either with positive lupus anticoagulants or with decreased activities of protein S, protein C, antithrombin III and/or plasminogen. Eight mutation sites were confirmed in 11 thrombotic patients using gene analysis. Decreased protein S activity was found with a high incidence (23 out of 115) in Japanese patients who suffered from not only venous thrombosis but also arterial and small vessel thrombosis. We emphasize here the important role of protein S in the pathogenesis of thrombosis in the Japanese population.

Effects of prolyl endopeptidase inhibitors and neuropeptides on delayed neuronal death in rats

We investigated the effects of the prolyl endopeptidase inhibitors 1-[1-(Benzyloxycarbonyl)-L-prolyl]prolinal (Z-Pro-Prolinal) and N-benzyloxycarbonyl-thioprolyl-thioprolinal-dimethylaceta l (ZTTA) on delayed neuronal death induced by four-vessel-occlusion transient ischemia in rats. We also examined the effects of [pGlu4, Cyt6, ArgS]vasopressin (vasopressin-(4-9)) and thyrotropin-releasing hormone (TRH) on the delayed neuronal death. Furthermore, we investigated the role of vasopressin receptors in the effects of vasopressin and prolyl endopeptidase inhibitors. Z-Pro-Prolinal, vasopressin-(4-9) and TRH protected pyramidal cells in the CA1 subfield of the rat hippocampus from delayed neuronal death after 10-min ischemia. The effect of vasopressin-(4-9) was abolished by vasopressin receptor antagonists. The effect of Z-Pro-Prolinal was also abrogated by the antagonists. These results suggest that the neuroprotective effect of prolyl endopeptidase inhibitors is mediated by neuropeptides such as [Arg8]vasopressin and TRH, and indicate the involvement of vasopressin receptors in the neuroprotective effect of vasopressin-(4-9) and prolyl endopeptidase inhibitors.

Antioxidant effects of albumin-bound sulfur in lipid peroxidation of rat liver microsomes

The antioxidant potential of albumin-bound sulfur (SBA) was investigated in rat liver microsomes using lipid peroxidation systems in vitro. Sulfur bound to protein is a reduced metabolite which is produced from cystine by gamma-cystathionase. Lipid peroxidation was induced either chemically by ferrous ions and ascorbate or enzymatically by carbon tetrachloride or tert-butyl hydroperoxide as indicated by the increase in thiobarbituric acid reactive substances (TBA-RS) and oxygen consumption. Although the antioxidant effect of SBA was weak on the non-enzymatic lipid peroxidation system, the addition of SBA significantly inhibited TBS-RS formation and oxygen consumption compared with non-treated bovine serum alubumin (BSA) in a microsomal lipid peroxidation system induced enzymatically. The sulfur bound to albumin disappeared during incubation with liver microsomes. However, slight differences in the disappearance were observed depending on whether or not lipid peroxidation was induced in the enzymatic systems. In the CCl4-induced lipid peroxidation system, the cytochrome P-450 level was significantly decreased by the addition of SBA. Therefore, in cytochrome P-450 dependent lipid peroxidation system, the potential effects of sulfur bound to albumin are due to an inhibition of cytochrome P-450 rather than by the oxidation itself caused by radical trapping.

Pilot study of combined treatment with continuous infusion of 5-fluorouracil, mitomycin C, and cisplatin (FMP) in patients with inoperable advanced gastric cancer

We investigated combined chemotherapy with 5-fluorouracil (600 mg/m2/day, day 1-5, c.i.v.), mitomycin-C (6 mg/m2, day 6), and cisplatin (60 mg/m2, day 7) for inoperable advanced gastric cancer, including those with poor performance status (PS). Overall response rates were 62.5% (20/32), 59.1% (12/22) for PS 0-2 and 70.0% (7/10) for PS 3-4. Median survival was 7.2 months, 8.7 for PS 0-2; and 6.3 for PS 3-4. There was no serious toxicity or any treatment-related death. This therapy is useful, even for poor PS.

Chemical control of Haematobia irritans with 0.5% topical ivermectin solution in cattle

A field trial was conducted to evaluate the efficacy of a topical formulation of ivermectin administered at the dose of 500 micrograms/kg against horn flies (Haematobia irritans) in cattle. Eighty-eight cattle in four herds naturally exposed to horn flies were used in the trial. Replicates were formed of two herds. Within replicates, one herd was randomly allocated to the untreated control and the other to the ivermectin treatment group. Horn fly counts were taken on the treatment day (Day 0) and on Days 7, 14, 21, 28, and 35 post-treatment. There were no horn flies on any cattle in the treatment group, whereas all the control cattle were continuously infested by horn flies on each examination day.

Neonatal hyperbilirubinemia and a common mutation of the bilirubin uridine diphosphate-glucuronosyltransferase gene in Japanese

Neonatal hyperbilirubinemia, which is prevalent among Asian peoples, has been considered as a physiological phenomenon, and its metabolic basis has not been clearly explained. Gilbert syndrome is a common inherited disease of unconjugated hyperbilirubinemia due to decreased bilirubin uridine diphosphate-glucuronosyltransferase (B-UGT), and its role in neonatal jaundice has recently been considered. We have previously reported that the Gly71Arg mutation of the B-UGT gene associated with Gilbert syndrome is prevalent in Japanese, Korean, and Chinese populations and was more frequently detected in neonates with severe hyperbilirubinemia than in control subjects. We have studied 159 Japanese full-term neonates, evaluating the relationship between the B-UGT genotype and the severity of jaundice, as assessed with a transcutaneous bilirubinometer. The gene frequency of the Gly71Arg mutation in these neonates was 0.19, and neonates carrying the Gly71Arg mutation had significantly increased bilirubin levels on days 2-4, manifested in a gene dose-dependent manner. The frequency of the Gly71Arg mutation was 0.47 in the neonates who required phototherapy (i.e., those with more severe hyperbilirubinemia), significantly higher than 0.16 in the neonates who did not require the therapy. The gene frequency of the TA repeat promoter polymorphism, the (TA)7 mutation, was 0.07, and neonates carrying this mutation did not have an increase in bilirubin. These results suggested that the Gly71Arg mutation contributes to the high incidence of neonatal hyperbilirubinemia in Japanese.

Synthesis and biological activity of KCB-328 and its analogues: novel class III antiarrhythmic agents with little reverse frequency dependence

A series of 3,4-dimethoxyphenethylamine derivatives was prepared, and their prolongation effects on effective refractory period of contractile response (ERPc) and action potential duration (APD) in isolated guinea-pig papillary muscles at 1 Hz and 3 Hz were examined. SAR studies led to the identification of KCB-328 (51) which is a novel class III antiarrhythmic agent with little reverse frequency dependence.

[Effects of Helicobacter pylori eradication therapy on the healing process of peptic ulcers]

The advent of H2-receptor antagonists (H2RA) and proton pump inhibitors (PPI) has particularly revolutionized the treatment of peptic ulcer disease. Most cases can now be successfully controlled by medical treatment with H2RA and PPI, but a high rate of ulcer recurrence remains an important problem. The quality of ulcer healing (QOUH) has therefore received increasing attention, and various investigators have attempted to define the conditions required for nonrecurrence. Ulcer scars with a good QOUH are considered to have a very low risk of recurrence. Recent studies have confirmed that recurrence of peptic ulcer can be suppressed markedly by eradication of Helicobacter pylori (H. p). Moreover, various types of endoscopic examinations (conventional observation, dye-contrast endoscopy, magnifying endoscopy, endoscopic ultrasonography, pharmacoendoscopy) have confirmed that the QOUH after eradication of H. p is better than that after conventional anti-ulcer therapy. H. p eradication therapy may become treatment of first choice for peptic ulcers.

Intellectual functions and regional cerebral haemodynamics after extensive omental transplantation spread over both frontal lobes in childhood moyamoya disease

Most accepted operations for childhood moyamoya disease have attempted to increase cerebral blood flow (CBF) in the ischaemic cortical areas around the central fissure. Developed ischaemic brain damage in the prefrontal area may lead to poor intellectual outcome and restrict patients' daily lives. Thus, extensive cerebral revascularization in both the ischaemic anterior and middle cerebral artery territories is mandatory. We describe the long-term follow-up results for intellectual outcome and performance status and make an evaluation of regional cerebral haemodynamics after extensive omental transplantation spread over both frontal lobes performed as the initial management. In the past 10 years, 10 moyamoya patients less than 12 years of age consecutively underwent omental transplantation. The omental flap was spread over not only the symptomatic hemisphere but also the contralateral frontal lobe after a large craniotomy. Superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis was accomplished simultaneously. On the contralateral hemisphere, STA-MCA anastomosis combined with encephalomyosynangiosis was subsequently performed. The clinical observation period averaged 6.7 years (ranged 1.9 to 9.2 years). Apart from 2 patients in whom severe mental retardation had been disclosed pre-operatively, full-scale intelligence quotient scores have been maintained at over 90, that is, within the normal intellectual range. With respect to quality of life (QOL), these 8 patients have been leading normal daily lives since the operation. The focal decrease in CBF observed in the frontal lobe pre-operatively in 7 cases had disappeared after surgical treatment. In these patients, serial post-operative MR angiography revealed developed omental vessels and STAs. Deterioration of intellectual functions and QOL as well as cerebral ischaemic events in paediatric moyamoya patients can be prevented by extensive omental transplantation spread over both frontal lobes combined with STA-MCA anastomosis.

Assay of nicotinamide deamidase activity using high-performance liquid chromatography

A rapid, simple and reproducible method has been developed for the determination of nicotinamide deamidase activity using high-performance liquid chromatography (HPLC). Nicotinic acid (NA) liberated from nicotinamide (NAA) after a 15-min enzyme reaction was determined directly by HPLC without further separation steps. Both NA, the product, and NAA, the substrate were separated by reversed-phase ion-pair isocratic chromatography and detected at 261 nm. The present method could be applied to the measurement of deamidase activity in crude cell extracts prepared from several bacterial strains. The Michaelis constant of nicotinamide deamidase in Enterobacter agglomerans was 36 microM for NAA. This method is useful for the measurement of nicotinamide deamidase from various sources.

A labile sulfur in trisulfide affects cytochrome P-450 dependent lipid peroxidation in rat liver microsomes

The effects of trisulfide derivatives were studied on cytochrome P-450-dependent lipid peroxidation using rat liver microsomal systems. Cytochrome P-450-dependent lipid peroxidation was induced by carbon tetrachloride or tert-butylhydroperoxide and was evident by an increase in thiobarbituric acid-reactive substances (TBA-RS) and oxygen consumption. In these cytochrome P-450-dependent lipid peroxidation systems, pretreatment of microsome with trisulfide derivatives (cystine trisulfide and thiocyclam) significantly inhibited TBA-RS formation and oxygen consumption compared with disulfide or thiol analogs (cystine, nereistoxin, or cysteine). The labile sulfur contained in trisulfide disappeared during incubation with liver microsomes. In the CCl4-induced lipid peroxidation system, the cytochrome P-450 level and NAD(P)H-cytochrome P-450 reductase activity were significantly decreased by the addition of trisulfide derivatives. Therefore, in cytochrome P-450-dependent lipid peroxidation system, the potential effects of trisulfide appear to be mediated via enzyme inhibition. These results suggest that pretreatment of the trisulfide derivatives may affect the toxic function of exogenous xenobiotics or drugs, which are reduced by the liver enzyme cytochrome P-450 to radical species.

Distribution of 14 elements in tissues and organs of oceanic seabirds

The concentrations of 14 trace elements (Li, V, Mn, Co, Cu, Zn, Se, Rb, Sr, Ag, Cd, Cs, Pb, and Hg) were determined in tissues and organs of three species and in the liver of 11 species of seabirds. Comparatively high concentrations of Li, Co, Sr, and V were found in the femur. Cd, Se, Cu, and Mn concentrations were relatively higher in the kidney than in other tissues and organs. Rb, Cs, and Pb concentrations were rather uniform among tissues. Concentrations of essential elements such as Mn, Cu, and Co were comparable among seabird species, except high Cu concentrations in northern giant petrel. Among nonessential elements, concentrations of Cd and Hg were variable according to seabird species. Pb levels were low in all the species. High Se levels (100 microg/g dry weight) were found in the liver of black-footed albatross and grey petrel. There were significant positive correlations between Se and Cd concentrations in three species and between Se and Hg in black-footed albatross, suggesting that Se has an antagonistic action on the toxic effects of Cd and Hg. Concentrations of Li, V, Ag, and Cs were usually low (less than 1 microg/g dry weight).

The GroEL-like protein from Campylobacter rectus: immunological characterization and interleukin-6 and -8 induction in human gingival fibroblast

The native GroEL-like protein was purified from Campylobacter rectus, a putative periodontal pathogen, by affinity chromatography on ATP-agarose followed by high performance liquid chromatography on Superose 6. The purified 64-kDa protein (denatured form of GroEL-like protein) was immunoreactive by SDS-PAGE and Western immunoblotting with the monoclonal antibody directed against heat shock protein 60 of human origin. The native GroEL-like protein stimulated both interleukin-6 (IL-6) and IL-8 secretion by a confluent monolayer of human gingival fibroblast in their culture supernatant. During the 22-h incubation, the amounts of IL-6 and IL-8 were increased by 5.4- and 3.5-fold, respectively. These data suggested that the GroEL-like protein might be considered to be a virulence factor of C. rectus in periodontal disease.

Age-dependent accumulation of heavy metals in baikal seal (Phoca sibirica) from the Lake Baikal

Concentrations of Fe, Mn, Zn, Cu, Cd, and Hg were determined in the liver, kidney, and muscle of 60 Baikal seals collected from Lake Baikal in 1992 to investigate age-dependent accumulation. Among essential elements, Fe concentrations in the muscle, liver, and kidney increased with age, suggesting development of diving ability. The concentrations of Mn, Zn, and Cu decreased with age, especially at immature stages. Toxic elements such as Hg and Cd decreased in adult males and thus the male-female difference was clearly observed in their concentrations, which differed from patterns usually found in marine mammals. Such accumulation patterns were due to difference in the feeding rates between males and females under low exposure to Hg and Cd. In addition, a greater excretion of Hg than that of Cd through molting and parturition was estimated.

Neonatal hyperbilirubinemia and mutation of the bilirubin uridine diphosphate-glucuronosyltransferase gene: a common missense mutation among Japanese, Koreans and Chinese

We analyzed the bilirubin uridine diphosphate-glucuronosyltransferase (B-UGT) gene in 42 Japanese newborns with hyperbilirubinemia and determined that 21 infants were heterozygous while 3 was homozygous for Gly71Arg. Allele frequency of Gly71Arg was 0.32 in newborns with hyperbilirubinemia, which was significantly higher than 0.13 in healthy Japanese controls. This mutant allele is also prevalent among Korean and Chinese healthy controls with a frequency of 0.23 in both populations. However, this mutation was not detected in 50 healthy German controls. These data suggest that the high frequency of the Gly71Arg mutation of the B-UGT gene is associated with high incidence of neonatal hyperbilirubinemia in Japanese, Korean and Chinese populations.

[Mallory-Weiss syndrome]

Mallory-Weiss syndrome is one of the cause of upper gastrointestinal hemorrhage, which an abrupt rise in abdominal pressure due to nausea or vomiting induces a tear near the esophagogastric mucosal junction. Mallory-Weiss syndrome represents about 3-15% of all cases of upper gastrointestinal hemorrhage. Mallory-Weiss tear is mainly located on the cardia part of the stomach side and spanning across the esophagogastric mucosal junction, only in esophageal side is rarely seen. Hemorrhage frequently ceases spontaneously. When endoscopic findings reveal persistent hemorrhage, endoscopic hemostatic technique using heater probe thermocoagulation or hemoclipping is necessary. After endoscopic hemostasis, fasting and inhibitors of acid secretion (H2-receptor antagonists or proton pump inhibitors) are recommended.

Staging of gastric cancer with endoscopic ultrasonography and endoscopic mucosal resection

Since it was found that the gastrointestinal wall is visualized as a five-layered structure corresponding to the histological layers of the wall, endoscopic ultrasonography (EUS) has become recognized clinically as the most accurate method for diagnosing and assessing the local staging of gastric cancer. However, some problems have remained, including how to differentiate between cancer invasion and ulcer fibrosis, how to detect microinvasion, and how to recognize malignant lymph nodes. Using the pattern analysis for depressed-type gastric cancer, it is usually possible to distinguish between cancer invasion and ulcer fibrosis, except in cases of microinvasion into ulcer fibrosis or inadequate scanning. However, the sensitivity of EUS for evaluating metastatic lymph nodes is still problematic. Endoscopic mucosal resection (EMR) for early gastric cancer has been widely accepted as a standard treatment in Japan due to its minimal invasiveness. According to our data, the overall rate of radical resection was 68.3% (168 of 246), and 31.7% of the remaining patients additionally received laser treatment, surgery, or heater-probe treatment. There were no deaths owing to gastric cancer. Some lesions in which there was microinvasion of the submucosa were incorrectly diagnosed by EUS. It may be possible to solve this problem using three-dimensional EUS (3D-EUS) in the near future.