Biomedical subjects

Y Terashima

Publications and source records attributed to Y Terashima.

At least 19 recordsLinked to original sources

PubMed2006

Ghrelin enhances glucose-induced insulin secretion in scheduled meal-fed sheep.

The purpose of this study was to investigate the effects of physiologic levels of ghrelin on insulin secretion and insulin sensitivity (glucose disposal) in scheduled fed-sheep, using the hyperglycemic clamp and hyperinsulinemic euglycemic clamp respectively. Twelve castrated Suffolk rams (69.8 +/- 0.6 kg) were conditioned to be fed alfalfa hay cubes (2% of body weight) once a day. Three hours after the feeding, synthetic ovine ghrelin was intravenously administered to the animals at a rate of 0.025 and 0.05 mug/kg body weight (BW) per min for 3 h. Concomitantly, the hyperglycemic clamp or the hyperinsulinemic euglycemic clamp was carried out. In the hyperglycemic clamp, a target glucose concentration was clamped at 100 mg/100 ml above the initial level. In the hyperinsulinemic euglycemic clamp, insulin was intravenously administered to the animals for 3 h at a rate of 2 mU/kg BW per min. Basal glucose concentrations (44+/- 1 mg/dl) were maintained by variably infusing 100 mg/dl glucose solution. In both clamps, plasma ghrelin concentrations were dose-dependently elevated and maintained at a constant level within the physiologic range. Ghrelin infusions induced a significant (ANOVA; P < 0.01) increase in plasma GH concentrations. In the hyperglycemic clamp, plasma insulin levels were increased by glucose infusion and were significantly (P < 0.05) greater in ghrelin-infused animals. In the hyperinsulinemic euglycemic clamp, glucose infusion rate, an index of insulin sensitivity, was not affected by ghrelin infusion. In conclusion, the present study has demonstrated for the first time that ghrelin enhances glucose-induced insulin secretion in the ruminant animal.

Animal Feed↗

PubMed2006

Photocatalytic oxidation of low concentration 2,4-D solution with new TiO2 fiber catalyst in a continuous flow reactor.

Environmental pollution by low concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) is a concern these days due to ever increasingly stringent regulations. Photocatalysis with immobilized TiO2 fiber is a promising oxidation method. Laboratory experiments on photocatalytic degradation of 0.045 mmol l(-1) 2,4-D with the world's first high-strength TiO2 fiber catalyst were carried out in a continuous flow reactor in which the degradations were, in general, similar to those with high 2,4-D concentrations investigated elsewhere. Degradation and mineralization of 2,4-D were significantly enhanced with no initial pH adjustments. The rate constants for total organic carbon (TOC) without pH adjustment were about two-fold bigger than the pH adjustment cases. CO2 gas measurement and carbon mass-balance were carried out for the first time, where about 34% organic carbon converted into CO2 gas during four-hour oxidation. 2,4-Dichlorophenol (2,4-DCP), phenol, benzyl alcohol and two unknowns (RT = 2.65 and 3.78 min.) were detected as aromatic intermediates while Phenol was the new aromatic in HPLC analysis. Dechlorination efficiencies were high (> 70%) in all the cases, and more than 90% efficiencies were observed in chloride mass balance. Bigger flow rates and solution temperature fixed at 20 degrees C without pH adjustment greatly enhanced 2,4-D mineralization. These results can be an important basis in applying the treatment method for dioxin-contaminated water and wastewater.

2,4-Dichlorophenoxyacetic Acid↗

PubMed2005

GH secretory responses to ghrelin and GHRH in growing and lactating dairy cattle.

Release of growth hormone (GH) is known to be regulated mainly by GH-releasing hormone (GHRH) and somatostatin (SRIF) secreted from the hypothalamus. A novel peripheral release-regulating hormone, ghrelin, was recently identified. In this study, differences of the GH secretory response to ghrelin and GHRH in growing and lactating dairy cattle were investigated and an alteration of plasma ghrelin levels was observed. The same amounts of ghrelin and GHRH (0.3 nmol/kg) were intravenously injected to suckling and weanling calves, early and mid-lactating cows and non-lactating cows. Plasma ghrelin levels were also determined in dairy cattle in various physiological conditions. The peak values of ghrelin-induced GH secretion were increased in early lactating cows compared to those in non-lactating cows. The relative responsiveness of GH secretion to ghrelin was also increased compared with that to GHRH in early lactating cows. GH secretory responses to GHRH were blunted in mature cows with and without lactation. Conversely, GHRH-induced GH secretory response was greater than that to ghrelin in calves, and also greater in calves than in mature cows. Plasma ghrelin concentrations were elevated in early lactating cows compared to those in non-lactating cows. Plasma GH concentrations were higher in suckling calves and early lactating cows compared with those in non-lactating cows. These results suggest that GHRH is an effective inducer of GH release in growing calves, and that the relative importance of ghrelin in contributing to the rise in plasma GH increases in early lactating cows.

Animals↗

PubMed2005

Changes in expression of the genes for the leptin receptor and the growth hormone-releasing peptide/ghrelin receptor in the hypothalamic arcuate nucleus with long-term manipulation of adiposity by dietary means.

Changes in leptin and ghrelin levels occur with alterations in adiposity, but signalling may be affected by levels of the relevant receptors. We measured expression of the leptin receptor (Ob-Rb) and the ghrelin/growth hormone releasing peptide receptor (GHS-R) in the arcuate nucleus of sheep held at either high or low levels of adiposity. Plasma growth hormone (GH) levels were lower in Fat animals and higher in Lean animals. Plasma insulin and leptin levels were higher in Fat animals and lower in Lean animals. Frozen hypothalamic sections of arcuate nucleus were extracted and mRNA levels measured for mRNA for Ob-Rb and GHS-R. Gene expression for both Ob-Rb and GHS-R was higher in Lean animals than in Fat animals, with no difference in expression between Fat and Normal animals. A second group of animals (n = 4 per group) was used for double-labelling immunohistochemistry to determine whether the increase in Ob-Rb gene expression was translated into Ob-Rb protein and to ascertain whether this effect is localised to the cells of the arcuate nucleus that produce either neuropeptide Y (NPY) and/or pro-opiomelanocortin-derived peptides. Lean animals displayed a 255% increase in immunoreactive NPY cells (P < 0.005), a 167% increase in cells with Ob-Rb (P < 0.037) protein and a 344% increase in cells that were staining for both NPY and Ob-Rb (P < 0.02). There was no difference between the Normal and Lean animals in the number of cells that were detected with an adrenocorticotrophic hormone (ACTH) antibody or the number of ACTH-immunoreactive cells that also stained for Ob-Rb. Finally, we measured plasma ghrelin levels in Normal, Fat and Lean ewes (n = 4/group); levels were higher (P < 0.05) in Fat animals than in Lean animals. We conclude that lowering body weight leads to increased expression of Ob-Rb, ghrelin/GHS-R expression and proportion of NPY cells that express Ob-Rb in the arcuate nucleus. This may be an adaptive mechanism to increase responsivity to both leptin and ghrelin.

Adipose Tissue↗

PubMed2004

Effects of ghrelin on food intake and neuroendocrine function in sheep.

Ghrelin, a novel acylated peptide, is the endogenous ligand for growth hormone secretagogue (GHS) receptor. Ghrelin is produced mainly in the oxyntic glands of the stomach, but also produced in the intestines, kidneys, hypothalamus and pituitary gland. Circulating ghrelin levels have been shown to rise before a meal and fall afterwards, suggesting that anticipation of a meal may stimulate secretion. In some species, ghrelin administration has been shown to stimulate growth hormone (GH) secretion, and to cause weight gain by increasing food intake and reducing metabolic utilization of fat. Furthermore, intracerebroventricular and intravascular administration of ghrelin increases gastric acid output in a dose-dependent manner. Thus, ghrelin may play an important role in controlling feeding behavior and energy homeostasis. We have investigated the role of ghrelin in the control of feeding and neuroendocrine function in ruminants using sheep as an experimental model. This mini review describes mechanisms regulating ghrelin secretion at feeding time, and also focuses on the neuroendocrine functions of ghrelin.

Animals↗

PubMed2004

Diurnal rhythm of cerebrospinal fluid and plasma leptin levels related to feeding in non-lactating and lactating rats.

Leptin suppresses food intake and increases energy expenditure in the hypothalamus. Rats consume most of their daily food intake during the dark phase of the diurnal cycle. Lactating rats have increased food intake, but the involvement of leptin in the regulation of food intake in this physiological condition is not well understood. The present experiment was carried out to determine the circadian pattern of leptin concentrations in plasma and cerebrospinal fluid (CSF) in relation to the feeding behavior of non-lactating and lactating rats. Female rats were maintained on a controlled lighting schedule (lights on between 0600 and 1800 h) and the food intake of lactating rats was two- or threefold higher than that of non-lactating rats. In both groups, food intake was three times greater in the dark phase (P<0.01) compared with the light phase. The plasma concentrations of leptin were lower (P<0.01) in lactating rats than non-lactating rats in both light and dark phases, but there were no differences in plasma leptin levels between light and dark phases. In contrast, and in both groups, the leptin concentrations in CSF were lower (P<0.01) in the dark phase than in the light phase. Leptin levels in CSF were lower (P<0.01) in lactating rats than in non-lactating rats. We conclude that a diurnal pattern of leptin levels within the brain (but not in plasma) reflects characteristics of feeding behavior in lactating and non-lactating rats.

Animals↗

PubMed2003

Circulating leptin response to feeding and exogenous infusion of insulin in sheep exposed to thermoneutral and cold environments.

Leptin has been shown to regulate feed intake and energy expenditure. Insulin stimulates leptin secretion in rodents, but its action on leptin secretion is still obscure in ruminants. If insulin stimulates leptin secretion in ruminants, circulating leptin concentrations may change during exposure to cold, because of fluctuating insulin secretion and action in the cold environment. The present experiment was designed to determine whether feeding or exogenous administration of insulin affects circulating leptin levels in sheep exposed to thermoneutral and cold environments. Suffolk rams that were shorn and fed a diet once daily were subjected to a thermoneutral (20 degrees C) or cold (0 degrees C) environment for at least 1 week. Overall mean concentrations of plasma leptin in the feeding experiment were lower (P<0.05) in the cold environment than in the thermoneutral environment. Plasma leptin levels remained relatively unchanged after feeding in both environments, though plasma insulin response to feeding in both environments increased (P<0.01). The euglycemic clamps (insulin infusion rate: 4 mUkgBW(-1)min(-1) for 2 h) increased (P<0.01) circulating leptin concentrations in the thermoneutral, but not in the cold environment. These results suggest that lower circulating leptin levels in ruminants exposed to the cold environment could be partly due to the depressed insulin action on leptin secretion.

Animals↗

PubMed2002

A transient ghrelin surge occurs just before feeding in a scheduled meal-fed sheep.

Ghrelin, a gastric-derived peptide, has recently been identified as an endogenous natural ligand for the growth hormone (GH) secretagogue receptor. However, secretory characteristics of ghrelin are still obscure in ruminants. To investigate the diurnal rhythm in ghrelin secretion and its relationship to GH secretion, plasma ghrelin and GH concentrations were determined in Suffolk rams fed with a roughage diet once daily (Experiment 1). Abrupt increases (P<0.05) in plasma ghrelin occurred just before a meal-feeding compared with that at 1h before feeding, then rapidly fell with a minimum during the feeding. A pulsatile surge (P<0.01) in plasma GH concentrations, which seemed to follow a single surge in plasma ghrelin, was observed during the feeding. In Experiment 2, plasma ghrelin and GH were determined in sheep subjected to a pseudo-feeding of 2h to determine whether feed ingestion itself influences ghrelin and GH secretions. Compared with those at 1h before feeding, a tendency of increases (P<0.1) in plasma ghrelin and significant increases (P<0.05) in GH occurred just before and during a pseudo-feeding, respectively. Plasma ghrelin temporally declined within 1h after the start of the pseudo-feeding, and increased again and maintained higher levels during the last period of the pseudo-feeding. These results suggest that the transient surge of ghrelin secretion just before a scheduled meal feeding would not be due to the ingestion of feed, and that a pulsatile increase in plasma GH during the actual- or pseudo-feeding could be induced by the transient ghrelin surge.

Animals↗

PubMed2002

Effects of dietary chitosan on fat deposition and lipase activity in digesta in broiler chickens.

1. The effect of dietary chitosan on fat deposition and lipase activity in the small intestinal contents was investigated in broiler chickens fed an adequate or high metabolisable energy (ME) diet. 2. Male broiler chickens at 14 d old were fed on the adequate or high ME diet supplemented with 0 or 50 g/kg chitosan, which has a low viscosity, for 3 weeks. 3. Dietary chitosan did not affect food intake, body weight gain or food efficiency in either dietary ME groups. 4. Dietary chitosan reduced the excessive abdominal fat deposition induced by the high ME diet. 5. Dietary chitosan increased the weight of intestinal contents irrespective of dietary ME concentration. 6. Dietary chitosan decreased the lipase activity per g of small intestinal contents. 7. These results suggest that dietary chitosan with low viscosity decreases lipase activity and fat absorption in the small intestine, consequently resulting in a reduction of fat deposition in broiler chickens. 8. It was concluded that dietary chitosan with low viscosity can decrease body fat deposition without reducing food intake and body weight gain in broiler chickens.

Abdomen↗

PubMed2001

Simultaneous resection of pancreas and liver metastases from different metachronous primary cancers.

Resection of a pancreatic head tumor and partial resection of the liver for metastatic lesions were carried out simultaneously in a 72-year-old woman. The patient had a history of two previous operations, right nephrectomy for renal cell carcinoma (clear cell type), done 14 years previously, and an Autincloss procedure for cancer of the left breast (solid tubular carcinoma); (T1N0M0; stage I) done 7 years previously. At the current presentation, preoperative radiographic examination showed a hypervascular tumor in each of the pancreatic and hepatic lesions, but with different patterns. On the basis of histological findings in the two resected specimens, it was difficult to establish whether the hepatic tumor originated from the renal cell carcinoma or the breast cancer, but postoperative immunohistochemical studies for carcinoembryonic antigen (CEA), estrogen receptors, and gross cystic disease fluid protein (GCDFP)-15 showed that the pancreatic tumor had metastasized from the renal cell carcinoma, and the liver tumor from the breast cancer. The immunohistochemical investigation of different markers thus proved to be useful in making the final diagnosis of metastatic lesions from different and metachronous cancers.

Aged↗

PubMed2001

Effect of hypomagnesemia and cold exposure on tissue responsiveness to insulin in sheep given a low magnesium and high potassium diet.

Hypomagnesemia in ruminants has been shown to be associated with cold stress and with altered insulin secretion and sensitivity. However, the relationship between hypomagnesemia and tissue responsiveness to insulin in ruminants exposed to cold environment is still unclear. The hyperinsulinemic euglycemic clamps, four insulin infusion rates (1, 2, 4 and 8 mU x kgBW(-1) x min(-1) for four sequential periods of 2-h each) were performed to determine combined effects of hypomagnesemia and cold exposure (0 degrees C) on tissue responsiveness to insulin in sheep. The low magnesium (0.05% Mg) and high potassium (4.20% K) diet and cold exposure decreased (P <.05) plasma Mg levels compared with those of the control diet (0.28% Mg/0.52% K) and the thermoneutral environment (20 degrees C). In the euglycemic clamps, cold exposure increased (P <.01) the pooled glucose infusion rate (GIR) across various insulin infusion rates in both diet treatments, though the increases in GIR were small for the low Mg/high K diet. In the cold environment, the GIR was lower (P <.01) for the low Mg/high K diet-fed sheep than for the control diet-fed sheep. The maximal insulin-induced increase in GIR was lower (P <.01) in the hypomagnesemic sheep than in the control sheep during cold exposure, and the insulin level resulting in half-maximal GIR tended to be higher in the hypomagnesemic sheep than in the control sheep. These results indicated that hypomagnesemia in ruminants depressed the enhanced tissue responsiveness to insulin in the cold environment, and decreased insulin-mediated glucose disposal.

Animals↗

PubMed2001

Effects of dietary protein level and cold exposure on tissue responsiveness and sensitivity to insulin in sheep.

The effects of dietary crude protein (CP) level and cold exposure on tissue responsiveness and sensitivity to insulin were studied in sheep. Nine rams were assigned to one of three isoenergetic diets which contained 70, 100, and 140% of CP for maintenance. They were exposed from a thermoneutral environment (20 degrees C) to a cold environment (0 degrees C) for 7 days. A hyperinsulinemic euglycemic clamp approach was applied for the determination of tissue responsiveness to insulin (the maximal glucose infusion rate, GIRmax) and tissue sensitivity to insulin (the plasma insulin concentration at half maximal glucose infusion rate, ED50). Dietary CP level influenced digestibilities of dry matter and CP (P=0.002 and P=0.001, respectively), and cold exposure decreased (P=0.01) CP digestibility. The GIRmax and ED50 tended to be influenced (P=0.08) by dietary CP level. The GIRmax was enhanced (P=0.0001) during cold exposure. Significant interactions between diet and environment were found for the GIRmax (P=0.04), but not for ED50 (P=0.07). It is concluded that in sheep dietary CP level can modify insulin action in response to cold exposure.

Animals↗

PubMed2001

An anti-inflammatory drug, propagermanium, may target GPI-anchored proteins associated with an MCP-1 receptor, CCR2.

Monocyte chemoattractant protein-1 (MCP-1) promotes the migration and activation of monocytes and plays a pivotal role in the development of chronic inflammation. Propagermanium (3-oxygermylpropionic acid polymer) has been used as a therapeutic agent against chronic hepatitis B in Japan. We report here that propagermanium specifically inhibits in vitro chemotactic migration of monocytes by MCP-1. Propagermanium did not inhibit binding of MCP-1 to a human monocytic cell line, THP-1 cells, or affect intracellular Ca(2+) mobilization or the cAMP concentration in MCP-1-treated THP-1 cells. The effect of propagermanium seems to require glycosylphosphatidylinositol (GPI)-anchored proteins, as cleavage of GPI anchors by phosphatidylinositol-phospholipase C (PI-PLC) eliminated the inhibitory activity of propagermanium. Anti-GPI-anchored protein antibodies, such as anti-CD55 and anti-CD59, reduced staining of C-C chemokine receptor 2 (CCR2) with an anti-CCR2 antibody against the N-terminus of CCR2 in a flow cytometric analysis, and these antibodies also selectively inhibited MCP-1-induced migration of THP-1 cells. Furthermore, under fluorescence microscopy, GPI-anchored proteins colocalized with CCR2 on THP-1 cells. These results suggest that propagermanium may target GPI-anchored proteins that are closely associated with CCR2 to selectively inhibit the MCP-1-induced chemotaxis, thus providing a mechanistic basis for the anti-inflammatory effects of the drug.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Distribution and diversity of symbiotic thermophiles, Symbiobacterium thermophilum and related bacteria, in natural environments.

Symbiobacterium thermophilum is a tryptophanase-positive thermophile which shows normal growth only in coculture with its supporting bacteria. Analysis of the 16S rRNA gene (rDNA) indicated that the bacterium belongs to a novel phylogenetic branch at the outermost position of the gram-positive bacterial group without clustering to any other known genus. Here we describe the distribution and diversity of S. thermophilum and related bacteria in the environment. Thermostable tryptophanase activity and amplification of the specific 16S rDNA fragment were effectively employed to detect the presence of Symbiobacterium. Enrichment with kanamycin raised detection sensitivity. Mixed cultures of thermophiles containing Symbiobacterium species were frequently obtained from compost, soil, animal feces, and contents in the intestinal tracts, as well as feeds. Phylogenetic analysis and denaturing gradient gel electrophoresis of the specific 16S rDNA amplicons revealed a diversity of this group of bacteria in the environment.

Animals↗

PubMed2001

Wastewater treatment and nitrogen removal using submerged filter systems.

The performance of two submerged filter systems: a two filters-in-series system and a single combined filter system, in treating a strong nitrogenous wastewater with nitrogen concentration of 480 mg/L was evaluated. Both systems were equally effective in removing up to 90% of nitrogen and 98% of COD from the wastewater for loading rates up to 5 kg COD/m3.d and 0.5 kg N/m3.d. The second system in which anaerobic, anoxic, and aerobic zones were incorporated in a single filter offers a greater flexibility in treatment in that by repositioning the locations of the aeration point and effluent recycling inlet, the zonal volumes can be altered easily to treat wastewaters with different COD and nitrogen concentrations.

Bacteria, Anaerobic↗

PubMed2000

Iron K Line Variability in the Low-Luminosity Active Galactic Nucleus NGC 4579.

We present results of new ASCA observations of the low-luminosity active galactic nucleus (LLAGN) NGC 4579 obtained on 1998 December 18 and 28, and we report on the detection of variability of an iron K emission line. The X-ray luminosities in the 2-10 keV band for the two observations are nearly identical (LX approximately 2x1041 ergs s(-1)), but they are approximately 35% larger than that measured in 1995 July by Terashima et al. An Fe K emission line is detected at 6.39+/-0.09 keV (source rest frame), which is lower than the line energy 6.73+0.13-0.12 keV in the 1995 observation. If we fit the Fe lines with a blend of two Gaussians centered at 6.39 and 6.73 keV, the intensity of the 6.7 keV line decreases, while the intensity of the 6.4 keV line increases, within an interval of 3.5 yr. This variability rules out thermal plasmas in the host galaxy as the origin of the ionized Fe line in this LLAGN. The detection and variability of the 6.4 keV line indicates that cold matter subtends a large solid angle viewed from the nucleus and that it is located within approximately 1 pc from the nucleus. It could be identified with an optically thick standard accretion disk. If this is the case, a standard accretion disk is present at the Eddington ratio of Lbol/LEdd approximately 2x10-3. A broad disk-line profile is not clearly seen, and the structure of the innermost part of accretion disk remains unclear.

Journal Article↗

PubMed2000

Intraoperative microwave coagulation therapy for large hepatic tumors.

We report new surgical techniques for intraoperative microwave coagulation therapy (IMCT), conducted in three patients with large liver neoplasms with poor liver function or difficult tumor location. Anterolateral thoracotomy was performed for tumors in the right lobe to obtain a good operative field. Four electrode needles were inserted for microwave irradiation, with settings of 60 W, 45 s for coagulation and 1 s for dissociation. Clamping of the hepatoduodenal ligament was performed during IMCT. We began the coagulation at the bottom of the tumor, irradiating the tumor and the surrounding parenchyma to create regional necrosis with a safe margin. With these methods, we treated two women diagnosed with large hepatocellular carcinoma with liver cirrhosis and a man with liver metastasis from rectal cancer. The postoperative course of these patients was uneventful. A marked low-density area was seen in the region of therapy and no enhanced findings were observed on enhanced computed tomography postoperatively. However, in one patient, transcatheter embolization (TAE) was performed 1 month postoperatively because recurrence was noted on the bottom of the tumor. Thus, IMCT destroys the peripheral part of the tumor that may remain viable after TAE, but combination therapy with TAE is preferable, especially when a viable part exists within tumors. IMCT is an active, safe, and nontoxic therapeutic modality for large hepatic tumors, and is particularly applicable in patients with large hepatocellular carcinomas and poor liver function.

Aged↗

PubMed2000

A phase II trial of docetaxel in platinum pre-treated patients with advanced epithelial ovarian cancer: a Japanese cooperative study.

BACKGROUND: This phase II study was conducted to evaluate the efficacy and toxicity of docetaxel in Japanese patients with advanced ovarian cancer. PATIENTS AND METHODS: Docetaxel was administered at a dose of 70 mg/m2 intravenously to patients with platinum pretreated advanced ovarian cancer. Treatment was repeated every three weeks. No routine corticosteroid premedication was given. RESULTS: Ninety patients with advanced ovarian cancer were entered and sixty were assessable for response. The overall response rate was 28% in the assessable patients (95% confidence interval (95% CI): 17.54%-41.4%). CA125 responses were seen in 8 (24%) of 34 assessable patients for CA125 criteria. The 36 platinum-refractory patients had a response rate of 25% compared with 33% in the platinum-sensitive patients. The predominant toxicity was neutropenia, with 86% of the patients experiencing grade 3 or 4. Hypersensitivity reactions occurred in 37% of the patients and were not life threatening. Edema was mild and infrequent. CONCLUSION: Docetaxel at 70 mg/m2 demonstrated effectiveness as a treatment of both platinum-sensitive and platinum-refractory ovarian cancer patients, with a low incidence of severe hypersensitivity reactions and edema.

Adult↗