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Biomedical subjects

H Fukumoto

Publications and source records attributed to H Fukumoto.

At least 91 records · Page 5Linked to original sources
PubMed1989

Combined revascularization of coronary and femoral arteries: a proposed alternative.

Two patients with both coronary artery disease and leg ischemia were successfully treated with a combined revascularization procedure. Coronary arteries were bypassed with in situ internal mammary artery grafts, and bilateral femoral arteries were bypassed with expanded polytetrafluoroethylene grafts descended from the ascending aorta through the preperitoneal abdominal wall tunnel. Both patients recovered well and experienced no angina or claudication.

Aged↗
PubMed1989

Short term effects of glucose and arginine on the preproinsulin messenger ribonucleic acid level in the perfused rat pancreas: comparison with insulin secretion.

To investigate the role of glucose and arginine in short term regulation of preproinsulin mRNA (ppImRNA) levels, the rat pancreas was perfused in the presence of glucose and/or arginine, and changes in ppImRNA levels in the pancreas were compared with the amount of insulin released during the perfusion. Perfusion of the pancreas with high glucose and arginine induced a significant increase in ppImRNA levels within 2 h, whereas perfusion with low glucose and arginine or high glucose alone had no significant effect during this period. The insulin release induced by perfusion of high glucose combined with arginine was 2 times greater than that induced by high glucose alone or low glucose with arginine. In conclusion, insulin gene transcription can be evoked during a short period in response to an extremely large secretory demand for insulin.

Animals↗
PubMed1989

Mechanism of erythropoietin action on the erythroid progenitor cells induced from murine erythroleukemia cells (TSA8).

Erythropoietin is a well-known erythroid differentiation and growth factor, but the mechanism of its action is not well understood. In this work, we have examined its mechanism of action on the erythropoietin-responsive murine erythroleukemia cells (TSA8). TSA8 cells become responsive to erythropoietin after induction with DMSO. Stimulatory effects on erythropoietin response are observed with the addition of compounds affecting the cAMP level such as forskolin, phosphodiesterase inhibitor and cholera toxin only in the presence of erythropoietin. cAMP analogues themselves show no stimulatory effect on TSA8 cells, nor does erythropoietin increase cAMP level in the cells. Thus, it is suggested that cAMP does not act as a direct second messenger for signal transduction through erythropoietin receptors, but as a stimulator of the erythropoietin receptor pathway and/or as a second messenger in combination with the receptor pathway. The mechanism for acquisition of responsiveness to growth and differentiation factors of progenitor cells is discussed.

Adenylyl Cyclases↗
PubMed1989

Different signalling pathways are used in the commitment of murine erythroleukemia cells (TSA8) to differentiate, and in the erythropoietin action on progenitor cells.

The murine erythroleukemia (MEL) cell line, TSA8, becomes responsive to erythropoietin after induction with dimethyl sulfoxide (DMSO). We examined the signalling pathways involved in the commitment of TSA8 cells to become the erythroid progenitor cells responsive to erythropoietin, comparing them with the pathway used in an erythropoietin-induced change of the progenitor cells. Amiloride, an inhibitor of the Na+/H+ antiporter, completely blocked the commitment of TSA8 cells to become responsive to erythropoietin at a concentration that did not affect cell proliferation, while it showed no effect on the differentiation or proliferation of the erythroid progenitor cells derived from TSA8 cells by erythropoietin. Ethyleneglycol-bis (beta-aminoethyl ether) N,N,N',N'-tetra acetic acid (EGTA) inhibited the commitment of TSA8 cells to CFU-E-like cells without affecting colony formation. In contrast, EGTA did not inhibit erythropoietin-induced differentiation of the progenitor cells, but did inhibit their proliferation. These results indicate that erythropoietin uses different signalling pathways from those used in the induction of the commitment of TSA8 cells.

Amiloride↗
PubMed1989

Results of multiple coronary artery bypass grafting in Japanese patients.

Multiple coronary artery bypass grafting with more than 4 grafts has been carried out in 64 Japanese patients during a 3.5 year period. There were 55 males and 9 females; ages ranged from 34 to 75 with a mean of 58.9 years old. Double, triple and left main disease were noted in one (2%), 54 (84%) and 9 (14%) patients, respectively. There was 54 (84%) stable and 10 (16%) unstable angina pectoris, and 28 (44%) patients had previous myocardial infarction. The saphenous vein graft was used for all patients with a preferential use of sequential graft (84%). The internal mammary artery graft was used in 55 (86%) patients and the right gastroepiploic artery graft was used in 6 (9%) patients. There were 2 (3.1%) early and 2 (3.1%) late deaths. New Q wave was noted in 2 (3.1%) patients and intraaortic balloon pumping was required in 3 (4.7%) patients. The mean number of grafts was 4.4 ranged from 4 to 7, and the mean aortic cross clamp time and cardiopulmonary bypass time was 74.5 min and 134.3 min, respectively. Graft patency within 6 postoperative months was 86% (120/140) in saphenous veins, 96% (52/54) in internal mammary arteries and 100% (5/5) in gastroepiploic arteries. Relief of angina was noted in 58 (96.7%) of 60 survivors. It was concluded that the increase in the number of coronary artery anastomoses does not increase surgical risk and favorable outcome and acceptable graft patency can be obtained by multiple grafting for patients with severe multivessel coronary artery disease.

Adult↗
PubMed1989

[Sequential internal mammary-coronary artery bypass].

A total of ten patients have undergone sequential bypass grafting of the internal mammary artery (IMA) to the coronary arteries at Osaka Medical College. Operative procedures included left IMA bypass to the left anterior descending (LAD) artery and its major diagonal branch in six patients; to the obtuse marginal branch and diagonal branch in three patients; and to the first and the second diagonal branches in one patient. The right internal mammary artery was concomitantly utilized in 4 patients and saphenous vein graft was also utilized in 6 patients. Postoperative angiographic studies were performed in nine patients within 6 months after operation and in all 18 sites of IMA anastomoses, the IMA sequential grafts were patent. Since sequential IMA-coronary bypass technique means the increase of arterial graft, we believe that this technique should be used for multivessel coronary revascularization especially in younger patients.

Adult↗
PubMed1988

Evidence for a family of human glucose transporter-like proteins. Sequence and gene localization of a protein expressed in fetal skeletal muscle and other tissues.

Complementary DNA clones encoding a glucose transporter-like protein have been isolated from a human fetal skeletal muscle cDNA library. The 496-amino acid fetal muscle glucose transporter-like protein has 64.4 and 51.6% identity with the previously described human erythrocyte/HepG2 and liver glucose transporter sequences, respectively. RNA blotting studies indicate that transcripts encoding this glucose transporter-like protein are present in most tissues, although their relative abundance varies. The gene encoding this protein has been localized to human chromosome 12p13.3. The identification and characterization of a third human glucose transporter-related protein suggests that there is a family of proteins having similar sequences and structures which are involved in nutrient transport by mammalian cells.

Amino Acid Sequence↗
PubMed1988

Effect of vitamin D on gastrin and gastric somatostatin secretion from the isolated perfused rat stomach.

We have studied the role of vitamin D in the regulation of gastrin and gastric somatostatin secretion from the isolated perfused rat stomach. In Ca-deficient vitamin D-deficient rats (Ca(-)D(-) group), the basal and bombesin-stimulated gastrin and gastric somatostatin release (basal IRGa, basal IRS, sigma delta IRGa, and sigma delta IRS) all were significantly lower than in Ca-replete vitamin D-replete rats (Ca(+)D(+) group), and also lower than in Ca-replete vitamin D-deficient rats (Ca(+)D(-) group) except for the basal IRGa. In the Ca(+)D(-) group, the basal IRGa and IRS, and sigma delta IRS were not significantly lower than in the Ca(+)D(+) group. Although there was no significant impairment in basal IRGa, sigma delta IRGa in the Ca(+)D(-) group was significantly lower than in the Ca(+)D(+) control group. Thus, the gastrin and gastric somatostatin secretion from the Ca-deficient vitamin D-deficient rats were impaired. In addition, the impaired gastrin and gastric somatostatin secretions seem to be caused not only by a decrease in serum Ca but also by the reduced effect of the vitamin D on the G and gastric D cells.

Animals↗
PubMed1988

Characteristic features of insulin secretion in the streptozotocin-induced NIDDM rat model.

Male Wistar neonatal rats at age 1.5 days (Streptozotocin [STZ] group 1) and 5 days (STZ group 2) received a subcutaneous injection of 90 mg/kg STZ. After 10 weeks, the rats were subjected to an oral glucose tolerance test (OGTT) (2 g/kg) in a conscious state. The pancreas perfusion experiments were conducted 2 weeks after the OGTT. There was no statistical difference in insulin response between the STZ group 1 and the control group. On the contrary, in the STZ group 2, the plasma glucose response to OGTT showed a typical diabetic pattern, and the plasma insulin response was markedly blunted. In the isolated perfused rat pancreas, the infusion of glucose evoked a biphasic insulin secretion, but the peak insulin levels induced by 16.7 mmol/L glucose in the STZ group 1 were significantly lower than in the controls. We further investigated characteristics of insulin secretion in response to different secretagogues in these animal models using isolated islets. The insulin content of the islets of the STZ group 1 were about one half that of the control group. Insulin secretion in the STZ group 1 was impaired in response to glucose stimulation, but remained normal in response to arginine and forskolin. These results suggest that insulin secretion of non-insulin-dependent diabetes mellitus (NIDDM) rat model is selectively impaired in response to glucose stimulation, possibly due to a disorder of signaling mechanism other than adenylate cyclase.

Animals↗
PubMed1988

Comparative effect of somatostatin-14 and somatostatin-28 on glucagon-induced glycogenolysis from the perfused rat liver.

The effect of somatostatin (SS)-14 and SS-28 on glycogenolysis was studied, using a rat liver perfusion technique. Livers from nonfasted rats were perfused with 5.5 mmol/L glucose or perfusate without the glucose addition. Glucagon-induced glucose output was lower in the presence of 5.5 mmol/L glucose than in glucose free perfusate at every concentration of glucagon. Under glucose free conditions, SS-14 given at five minutes prior to the glucagon addition reduced the glucagon-induced glucose output dose-dependently. SS-14 given 15 minutes after glucagon addition also inhibited glucagon-induced glucose output significantly. However, various concentrations of SS-28 failed to affect glucose output. On the other hand, in the presence of 5.5 mmol/L glucose, neither SS-14 nor SS-28 affected glucagon-induced glucose output. It is suggested, therefore, that glycogenolysis induced by glucagon from the liver is reduced by SS-14, but not by SS-28, only under glucose free conditions.

Animals↗
PubMed1988

Sequence, tissue distribution, and chromosomal localization of mRNA encoding a human glucose transporter-like protein.

cDNA clones encoding a glucose transporter-like protein have been isolated from adult human liver and kidney cDNA libraries by cross-hybridization with the human HepG2/erythrocyte glucose transporter cDNA. Analysis of the sequence of this 524-amino acid glucose transporter-like protein indicates that it has 55.5% identity with the HepG2/erythrocyte glucose transporter as well as a similar structural organization. Studies of the tissue distribution of the mRNA coding for this glucose transporter-like protein in adult human tissues indicate that the highest amounts are present in liver with lower amounts in kidney and small intestine. The amounts of glucose transporter-like mRNA in other tissues, including colon, stomach, cerebrum, skeletal muscle, and adipose tissue, were below the level of sensitivity of our assay. The single-copy gene encoding this glucose transporter-like protein has been localized to the q26.1----q26.3 region of chromosome 3.

Amino Acid Sequence↗
PubMed1988

Differentiation of erythroid progenitor (CFU-E) cells from mouse fetal liver cells and murine erythroleukemia (TSA8) cells without proliferation.

Erythropoietin (epo) appears to play a significant role in influencing the proliferation and differentiation of erythroid progenitor (CFU-E) cells. To determine the mechanism of action of epo, the effect of drugs on the in vitro colony formation of CFU-E cells induced from a novel murine erythroleukemia cell line, TSA8, was examined. While cytosine arabinoside inhibited colony formation and terminal differentiation of the CFU-E cells responding to epo, herbimycin, which is a drug that inhibits src-related phosphorylation, inhibited colony formation only. The same effect of herbimycin was observed with normal CFU-E cells from mouse fetal liver cells. These results suggest that epo induces two signals, one for proliferation and the other for differentiation, and that the two signals are not linked in erythroid progenitor cells.

Animals↗
PubMed1988

Degradation and conversion of somatostatin in normal and diabetic rats in vivo and in vitro.

Plasma somatostatin-like immunoreactivity in the portal and jugular veins of streptozotocin diabetic rats was compared with that in normal control rats. In the diabetic group, somatostatin levels in the portal (p less than 0.05) and jugular (p less than 0.01) veins were both elevated compared with those in the control group. Moreover, the degree of elevation was greater in the jugular vein than in the portal vein. To further investigate the role of the liver in the clearance of somatostatin-28 in vivo, 2 micrograms of somatostatin-28 was administered as a bolus into the external jugular vein of intact and functionally hepatectomized rats. The mean half-time of somatostatin-28 was significantly longer in intact diabetic rats than in controls (p less than 0.05). The functional hepatectomy did not cause a significant difference in the half-time in diabetic rats but made it longer in control rats. These results suggest that the longer half-time of somatostatin-28 in diabetic rats in vivo is due to its slower hepatic clearance. The hepatic clearance of somatostatin-28 and somatostatin-14 was further studied in vitro using a recirculating liver perfusion method. The hepatic clearance of 1.2 nM of either somatostatin-28 or somatostatin-14 was significantly lower in diabetic rats than in controls (p less than 0.01). This indicates that elevated plasma somatostatin levels in diabetic rats are caused at least in part by decreased hepatic clearance of somatostatin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Coronary artery bypass grafting by utilizing the internal mammary artery graft in 100 Japanese patients.

The internal mammary artery (IMA) grafting for myocardial revascularization was performed in 100 Japanese patients during a three-year period. There were 86 males and 14 females with the mean age of 58 +/- 9 (37 approximately 75 year-old). Unilateral IMA was used in 88 patients and bilateral IMA was used in 12 patients. Sequential IMA grafting was performed in 5 patients. The sites of IMA grafting were 91 left anterior descending arteries (LAD), 16 diagonal branches, 8 circumflex arteries and 2 right coronary arteries. Saphenous vein or gastroepiploic artery was concomitantly used to bypass the other coronary arteries in 90 patients. The number of distal anastomosis ranged from 1 to 6 and the mean was 2.8 per patient. Two patients died within 30 days and one patient died at 3 months after surgery. Perioperative myocardial infarction was noted in 3 patients. Symptomatic relief was obtained in 94 (97%) of 97 survivors. The patency of the IMA graft at mean 2.2 postoperative months was 97% (58/60) in LAD, 100% (14/14) in the diagonal branch, 100% (5/5) in the circumflex artery, 100% (1/1) in the right coronary artery, and 98% (78/80) in over-all grafted coronary arteries. Pre- and postoperative exercise thallium scintigraphy in 13 patients, who received the IMA graft to severely stenosed LAD, showed significant improvement of the washout ratio (from 33.1 +/- 16.9% to 47.4 +/- 14.8%) which was nearly equivalent to that of the saphenous vein graft to LAD (from 24.8 +/- 6.2% to 48.1 +/- 6.6%, n = 7).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Characterization and expression of human HepG2/erythrocyte glucose-transporter gene.

The human HepG2/erythrocyte glucose-transporter gene, including the promoter region, has been isolated and characterized. The gene, which is approximately 35,000 base pairs, is interrupted by nine intervening sequences or introns. The sequence of the HepG2 glucose-transporter protein predicted from the gene sequence differs from that determined from the published cDNA sequence in having Leu rather than Phe at position 152. In addition, there are several other nucleotide differences between the gene and cDNA sequences in both the coding region and 3'-untranslated region that do not alter the amino acid sequence of the protein. The sequence of the promoter and the site of transcription initiation have also been determined. The promoter region includes a TATA motif and two binding sites for the transcription factor Spl as well as a sequence that is found in the promoter region of several phorbol ester-inducible genes.

Carcinoma, Hepatocellular↗