Search PubMed⌕ Search

Biomedical subjects

H Ishihara

Publications and source records attributed to H Ishihara.

At least 361 records · Page 20Linked to original sources
PubMed1993

[Hemodynamic and endocrine responses to prostaglandin E1 induced hypotension during enflurane anesthesia in surgical patients--evaluation by transesophageal echocardiography].

This study was undertaken to find a relationship between cardiac function indices and endocrine functions during prostaglandin E1 induced hypotension in surgical patients. Thirteen patients who underwent either orthopedic or gynecologic surgery were the subjects of the study. Systolic blood pressure decreased to 80 torr with prostaglandin E1 infusion (0.5-2 micrograms.kg-1 x min-1) under enflurane-N2O anesthesia. The cardiac function were judged by transesophageal echo-cardiography. Plasma ANP and ADH levels were measured by radioimmunoassay. Significant reductions in the left atrial diameter and A/R and significant increases in cardiac output were observed, but there were no significant changes in fractional shortening and pulmonary vein flow. Plasma ANP concentrations decreased significantly from 45.3 +/- 5.1 pg.ml-1 (mean +/- SE) of pre-hypotension to 32.6 +/- 2.2 pg.ml-1 of control, but plasma ADH levels increased significantly during hypotension (P < 0.05). We could not find any significant correlation between the cardiac function indices and plasma hormone levels. Transesophageal echocardiography is an excellent monitor during induced hypotension. It is difficult to predict the ANP and ADH levels by measuring cardiac function as judged by TEE.

Adult↗
PubMed1993

[Effects of intravenous infusion of isosorbide dinitrate on hemodynamics during anesthesia and surgery].

Ninety nine patients with ischemic changes of the heart on preoperative and intraoperative ECG tracings were studied to evaluate effects of intravenous infusion of isosorbide dinitrate on hemodynamics during anesthesia and surgery. These patients ranging in ages from 24 to 80 years were administered intravenous isosorbide dinitrate at a rate of either 0.5 or 1 microgram.kg-1 x min-1 during anesthesia and surgery. Arterial blood pressure was not influenced with intravenous isosorbide dinitrate at the speed of 0.5 microgram.kg-1 x min-1 during anesthesia and surgery. The arterial pressure of the patients decreased slightly but significantly 30 min after the start of 1 microgram.kg-1 x min-1 of isosorbide dinitrate infusion, but it recovered to the control level at the end of administration of isosorbide dinitrate. Heart rate was unchanged with intravenous isosorbide dinitrate during anesthesia and surgery in both groups, except a mild increase at the end of isosorbide dinitrate infusion of 1 microgram.kg-1 x min-1. Arterial blood oxygen tension showed no decrease during the administration of isosorbide dinitrate and no adverse reactions associated with administration of the drug was detected in this study. Significant improvement of ischemic changes on ECG tracings were observed in about 25% of the patients who received 1 micrograms.kg-1 x min-1 of intravenous isosorbide dinitrate.

Adult↗
PubMed1993

[Clinical study of total intravenous anesthesia with droperidol, fentanyl and ketamine--effects of nicardipine, diltiazem and nifedipine on intraoperative hypertension].

Effects of Ca ion channel blockers, nicardipine, diltiazem and nifedipine on intraoperative hypertension were evaluated clinically in ninety surgical patients who received various surgical procedures under total intravenous anesthesia with droperidol, fentanyl and ketamine. When the systemic blood pressure exceeded 160 mmHg systolic at least for ten minutes, even though they received a total dose of 10-15 micrograms.kg-1 of fentanyl, one of the following three antihypertension drugs was administered:nicardipine 0.5-1.0 micrograms i.v., diltiazem 5-10 mg i.v. and nifedipine 5-10 mg intranasally. The effects were evaluated by measuring the systemic blood pressure, heart rate and rate pressure product, before the administration as well as 5, 15, 20 and 30 minutes after the administration. Following the injection of the drug a significant 10-20% reduction in the mean systemic blood pressure was observed in the nifedipine group, while less decrease was observed in the diltiazem and nicardipine groups. The mean heart rate in the nifedipine group increased slightly, while a slight decreases was observed in the other two groups. Therefore the rate pressure product was reduced significantly in three groups, but there was no significant difference among them. No adverse episodes such as ischemic changes on E.K.G. and deterioration of the cardiovascular system were encountered in any patients. We conclude that any of these drugs, particularly nifedipine would be appropriate to control hypertension during total intravenous anesthesia with droperidol, fentanyl and ketamine.

Anesthesia, Intravenous↗
PubMed1993

Structural variation of the anterior and posterior anulus fibrosus in the development of human lumbar intervertebral disc. A risk factor for intervertebral disc rupture.

A morphologic comparison of the laminated structure of the anterior and posterior anulus fibrosus of lumbar intervertebral disc was made on 24 L3-4 and L4-5 discs obtained from 10 fetus, one child, and one young adult cadavers. Low power microscopic and polarized microscopic observations and measurements on the transverse sections were performed to assess 1) lamellar bundle arrangement, 2) number of distinct lamellar bundles, 3) percentage of incomplete lamellar bundles, and 4) fiber-interlacing angles. The number of lamellar bundles was greater in the anterior anulus than in the posterior anulus. A very complex structure was observed in the posterior middle anulus in all the specimens, with a high percentage of incomplete/discontinuous lamellar bundles and greater fiber-interlacing angles. Loose connection of the lamellar bundles of posterior outer anulus was observed in fetal discs. The annular strength was not measured in the present study, however, the risk of posterior disc rupture in the young may be influenced by an inherent structural variation with a weak posterior anulus fibrosus.

Adult↗
PubMed1993

Occurrence of heterogeneity of N-linked oligosaccharides attached to sycamore (Acer pseudoplatanus L.) laccase after excretion.

The N-linked oligosaccharide moieties of sycamore (Acer pseudoplatanus L.) laccase are known to be highly heterogeneous. We confirmed that this oligosaccharide heterogeneity was caused not only during the oligosaccharide biosynthesis in Golgi apparatus, but also after the excretion of laccase protein into a culture medium. The culture medium for the sycamore cells (Acer pseudoplatanus L.) contained beta-galactosidase, alpha-L-fucosidase, beta-N-acetylglucosaminidase, alpha-mannosidase and beta-xylosidase activities. We showed that the largest sugar chain in laccase, oligosaccharide F, [formula: see text] was degraded to [formula: see text] by a crude exoglycosidase mixture in the culture medium.

Acetylglucosaminidase↗
PubMed1993

[Anesthetic experience of emergency cesarean section for a patient with myotonic dystrophy].

We report an anesthetic experience of a 28-year-old female patient complicated with myotonic dystrophy who underwent emergency Cesarean section due to threatened abortion. Anesthesia was induced with intravenous thiopental followed by topical spray of 4% lidocaine 5 ml to intubate trachea and maintained with neuroleptanesthesia with droperidol, fentanyl and nitrous oxide in oxygen. No muscle relaxant was used. The course of anesthesia and emergence from anesthesia were uneventful. However, the female infant, with Apgar score of 1 point at five minutes after delivery, died due to multiple organ failure three weeks after the delivery. Anesthetic management of a patient with myotonic dystrophy was also discussed with a literature review.

Abortion, Threatened↗
PubMed1992

Nonsense mutation of glucokinase gene in late-onset non-insulin-dependent diabetes mellitus.

A nonsense mutation at codon 186 in exon 5 of the gene for glucokinase, an enzyme important for glucose-induced insulin secretion, was identified in a Japanese patient with late-onset non-insulin-dependent diabetes mellitus (NIDDM). All affected members of her family were heterozygous for the mutation and had late-onset NIDDM or impaired glucose tolerance, whereas unaffected members showed normal glucose tolerance. The early insulin response to oral glucose was impaired in affected relatives, but was normal in those unaffected. These findings suggest that the glucokinase mutation raises the set-point of pancreatic beta cells for glucose-induced insulin secretion, leading to abnormal glucose tolerance in some patients with late-onset NIDDM.

Adolescent↗
PubMed1992

Characterization of GLUT3 protein expressed in Chinese hamster ovary cells.

We have expressed GLUT3 protein, an isoform of a facilitative glucose transporter, in Chinese hamster ovary cells by transfection of its cDNA using an expression vector. The expressed GLUT3 protein was detected by Western-blot analysis as a broad band of 45-65 kDa, indicating intensive glycosylation of the protein. The expressed GLUT3 protein was observed, by immunofluorescence staining, to be located mainly at the plasma membrane, and its expression was associated with a marked increase in glucose-transport activity. Kinetic analysis revealed that the Km value of GLUT3 protein for 3-O-methylglucose uptake was approx. 35% of that of GLUT1 protein, whereas the Km value of GLUT3 protein for 2-deoxy-D-glucose uptake was very similar to that of GLUT1 protein. The Vmax. value of GLUT3 protein for 3-O-methylglucose and 2-deoxyglucose uptake was approx. 20-50% of that of GLUT1 protein. GLUT3 protein was well photolabelled with [3H]cytochalasin B or a mannose derivative, 2-N-4-[3H](1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis-(D-mannos -4-yloxy)-2- propylamine. Thus GLUT3 protein has very similar characteristics to GLUT1 protein including its subcellular localization, but exhibits lower Km and Vmax. values for 3-O-methylglucose uptake.

3-O-Methylglucose↗
PubMed1992

Replacement of intracellular C-terminal domain of GLUT1 glucose transporter with that of GLUT2 increases Vmax and Km of transport activity.

The intracellular C-terminal domain is diverse in size and amino acid sequence among facilitative glucose transporter isoforms. The characteristics of glucose transport are also divergent, and GLUT2 has far higher Km and Vmax values compared with GLUT1. To investigate the role of the intracellular C-terminal domain in glucose transport, we expressed in Chinese hamster ovary cells the mutated GLUT1 protein whose intracellular C-terminal domain was replaced with that of GLUT2 by means of engineering the chimeric cDNA. Cytochalasin B, for which GLUT2 protein has much lower affinity, bound to this chimeric protein in a fashion similar to GLUT1. In contrast, greater transport activity was observed in this chimeric glucose transporter compared with the wild-type GLUT1 at 10 mM 2-deoxy-D-glucose concentration. The kinetic studies on 2-deoxy-D-glucose uptake revealed a 3.8-fold increase in Km and a 4.3-fold increase in Vmax in this chimeric glucose transporter compared with the wild-type GLUT1. Thus, replacement of the intracellular C-terminal domain confers the GLUT2-like property on the glucose transporter. These results strongly suggest that the diversity of intracellular C-terminal domain contributes to the diversity of glucose transport characteristics among isoforms.

Amino Acid Sequence↗
PubMed1992

Domains responsible for the differential targeting of glucose transporter isoforms.

Facilitative glucose transporter isoforms, GLUT1 and GLUT4, have different intracellular distributions despite their very similar structure. In insulin-responsive tissues such as adipose tissues and muscle, GLUT4 protein resides mainly in the intracellular region in a basal condition and is translocated to the plasma membrane upon stimulation of insulin. In contrast, GLUT1 protein was distributed about equally between plasma membranes and low density microsomal membranes in 3T3-L1 adipocytes. Furthermore, GLUT1 and GLUT4 were reported to be differentially targeted to the plasma membrane and intracellular region, respectively, when expressed in Chinese hamster ovary cells and HepG2 cells. To elucidate the differential intracellular targeting mechanisms, several chimeric glucose transporters in which portions of GLUT4 are replaced with corresponding portions of GLUT1 have been stably expressed in Chinese hamster ovary cells. Immunofluorescence and immunoelectron microscopy as well as measurement of glucose transport activity revealed that two domains of GLUT4, which are not the NH2- or COOH-terminal domain, determine its targeting to the intracellular vesicles. The first domain contains the consensus sequence of the leucine zipper structure, suggesting that a dimer-forming structure of the glucose transporter might be required for its proper targeting. The other domain contains 28 amino acids, nine of which are different between GLUT1 and GLUT4. Immunoelectron microscopy revealed that the chimeric transporters containing both of these two domains of GLUT1, only the first domain of GLUT1, and none of the domains, exhibited a different cellular distribution with approximately 65, 30, and 15% of the transporters apparently on the plasma membrane, respectively. The addition of insulin did not alter the apparent cellular distributions of these chimeric transporters. These domains would be specifically recognized by intracellular targeting mechanisms in Chinese hamster ovary cells.

Animals↗
PubMed1992

Preferential expression of immunoreactive fucosylceramide in adenocarcinoma of the lung.

The expression of fucosylceramide (PC47H antigen) in 97 lung cancers and 4 extrapulmonary squamous cell carcinomas was examined with the use of a novel monoclonal antibody, PC47H, recognizing fucosylceramide specifically. The observed variation in fucosylceramide content was dependent on the degree of glandular differentiation in adenocarcinoma of the lung. Fucosylceramide was abundantly expressed in well differentiated adenocarcinoma of the lung and poorly expressed in poorly differentiated adenocarcinoma. Some squamous cell carcinomas of the lung reacted with this monoclonal antibody weakly, but the reaction was noted only at the periphery of the epithelial sheets. Extrapulmonary squamous cell carcinoma and small-cell carcinomas did not react with monoclonal antibody PC47H. Interestingly, large cell carcinomas of uncertain cell origin were all positive for fucosylceramide, which accumulated in the cytoplasm. At the ultrastructural level, fucosylceramide was located in the plasma membrane and unit membrane of the rough endoplasmic reticulum. On the other hand, carcinoembryonic antigen as an adenocarcinoma-associated tumor marker was expressed significantly in squamous cell carcinomas as well as adenocarcinomas. Taken together, fucosylceramide seems to be expressed preferentially in adenocarcinomas, and is closely linked to glandular differentiation. Thus it may be a better tumor marker than carcinoembryonic antigen.

Adenocarcinoma↗
PubMed1992

Deletion of C-terminal 12 amino acids of GLUT1 protein does not abolish the transport activity.

We engineered the GLUT1 cDNA to delete C-terminal 12 amino acids of encoded GLUT1 protein. This mutated GLUT1 protein expressed in CHO cells by transfection of its cDNA was demonstrated to reside on the plasma membrane by cell surface labeling technique, and retain the transport activity, similar to that of the wild-type GLUT1. In addition, metabolic labeling of the intact cells with 35S indicated that the half-life of the mutated GLUT1 was not significantly different from that of the wild-type GLUT1. These results suggest that C-terminal 12 amino acids of GLUT1 are not important for the transport activity and the stability of the protein. Taken together with our previous results on the mutant without C-terminal 37 amino acids, the amino acids between the 37th and the 13th from the C-terminus appear to be essential for the transport activity.

Animals↗
PubMed1992

Glycolipid of human pancreatic cancer; the appearance of neolacto-series (type 2 chain) glycolipid and the presence of incompatible blood group antigen in tumor tissues.

Glycolipid isolated from normal and cancerous human pancreatic tissues were characterized chemically and immunologically. The major neutral glycolipids in both normal and cancerous tissues were composed of globo-series glycolipids and lacto-series glycolipids. The mole percentage of fucolipids in the total neutral glycolipids of normal tissues was 20-40%, and in general the fucolipids corresponded to blood group glycolipids related to the patient's blood group, however, in cancerous tissues the amount of these fucolipids was decreased. Immunostaining revealed that normal tissues contained only lacto-series (type 1 chain) glycolipids. In contrast, cancerous tissues contained the neolacto-series (type 2 chain) glycolipids as well as the lacto-series glycolipids. Incompatible blood group antigens, A active glycolipids in a blood type O patient and B active glycolipids in a blood type A patient, were also detectable in the neutral glycolipid fractions of the pancreatic cancer tissues.

Adenocarcinoma↗
PubMed1992

Glucose binding enhances the papain susceptibility of the intracellular loop of the GLUT1 glucose transporter.

Digestion of human GLUT1 protein in erythrocytes with 5 micrograms/ml papain for 5 min yielded several fragments. By using several site-specific antibodies, two of these fragments containing the intracellular loop domain between M6 and M7 were demonstrated to be further digested by a prolonged incubation with papain. The addition of 0.2 M D-glucose enhanced this digestion between M6 and M7 by approximately 3.5-fold, while the addition of 0.2 M D-sorbitol exhibited no effects. These results strongly suggest that D-glucose binding induces the conformational change of the intracellular loop domain between M6 and M7 of GLUT1 protein. Since the homology of the amino acid sequence was low in this intracellular domain among the five facilitative glucose transporter isoforms, this intracellular loop might contribute to the difference in their Km and Vmax values for glucose uptake.

Erythrocyte Membrane↗
PubMed1992

Two glucose transporter isoforms are sorted differentially and are expressed in distinct cellular compartments.

Rat GLUT4 (adipocyte/muscle-type glucose transporter) was expressed in two fibroblastic cell lines, Chinese hamster ovary (CHO) cells and 3T3-L1 fibroblasts, under the control of the methallothionein I promoter. Although immunoblotting with a GLUT4-specific anti-peptide antibody demonstrated that the amount of GLUT4 expressed was comparable with that in 3T3-L1 adipocytes and rat adipose tissues, no increase in 2-deoxy-D-glucose uptake was observed in the basal state in fibroblasts. Immunocytochemical studies showed that the expressed GLUT4 appeared to be localized in a specific region in the cytoplasm. These results were in marked contrast to those obtained in CHO cells expressing GLUT1 (HepG2/erythrocyte-type glucose transporter) using the same expression vector. In this case the expressed GLUT1 protein appeared to reside mainly on the plasma membranes, and a significant increase in glucose uptake was observed. Although insulin increased glucose uptake in CHO cells and 3T3-L1 fibroblasts as well as in the cells expressing rat GLUT4, an increment due to insulin above basal values was small, at most 2-fold, and no significant differences were observed in insulin-stimulated glucose uptake between transfected and parental cells. In addition, no apparent differences in the subcellular distribution of expressed GLUT4 were observed between the insulin-stimulated and the basal state. These results indicate that in fibroblastic cell lines GLUT1 and GLUT4 proteins are sorted in a different fashion, and the expression of GLUT4 protein per se is not enough to produce a large insulin-induced increase in glucose transport activity such as that observed in rat adipocytes and 3T3-L1 adipocytes. Thus unidentified aspects of the cellular environment which are present in the adipocytes but not in fibroblastic cell lines may be required for a large insulin-induced increase in glucose transport activity to be observed.

Adipose Tissue↗