Search

On addition of DMSO, the MEL cell line TSA8 becomes committed into erythroid progenitor cells (CFU-E) which can form differentiated colonies in the presence of erythropoietin. To understand the mechanism of cellular commitment, the number and the affinity of the receptors for erythropoietin were estimated. The affinity of the receptors did not change before or after induction. The number of receptors changed depending on the growth phase, but was not dependent on the addition of the inducer. Thus, the presence of the receptors for erythropoietin may be required, but are not essential for responsiveness to erythropoietin. Further examination of the optimum conditions for commitment suggests that the concomitant actions of induced factor(s) with the receptors may control commitment of TSA8 cells to CFU-E.

Gastric inhibitory polypeptide (GIP) is a 42-amino acid hormone that stimulates insulin secretion in the presence of glucose. Complementary DNA clones encoding human GIP were isolated from a library prepared with RNA from duodenum. The predicted amino acid sequence indicates that GIP is derived by proteolytic processing of a 153-residue precursor, preproGIP. The GIP moiety is flanked by polypeptide segments of 51 and 60 amino acids at its NH2 and COOH termini, respectively. The former includes a signal peptide of about 21 residues and an NH2-terminal propeptide of 30 amino acids. GIP is released from the precursor by processing at single arginine residues. There is a region of nine amino acids in the COOH-terminal propeptide of the GIP precursor that has partial homology with a portion of chromogranin A as well as pancreastatin.

2[2-(4.5-Dihydro-1H-imidazol-2-yl)-1-phenylethyl] pyridine dihydrochloride sesquihydrate (DG-5128) is an alpha 2-specific-adrenergic antagonist. We have studied the effect of DG-5128 on insulin and somatostatin release from the isolated perfused rat pancrease. DG-5128 stimulated somatostatin and insulin release not only at a low glucose concentration but also at a high glucose concentration. These findings suggest that an alpha 2-adrenergic receptor plays an important role in the regulation of insulin and somatostatin secretion.

A longitudinal study was performed in an island, endemic for Bancroftian filariasis, by blood survey and skin test from the beginning of a filariasis control campaign in 1967 through 1980. The initial microfilarial rate of 13.2% was successfully reduced to almost 0 by 1970, by the selective administration of diethylcarbamazine to microfilaria positives. The age distribution of skin-test positivity changed year by year, especially in the younger age groups. A marked reduction was seen in the positive rate in the 0- to 9- and 10- to 19-year-old age groups. The change of skin reactivity for all islanders was evaluated, and revealed a gradual decrease in the wheal-size over the observation period.

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)

The results of internal mammary artery grafting in 50 patients with a body surface area less than 1.6 m2 were compared with those in 54 patients with a larger body surface area. Age (58.8 +/- 8.2 versus 54.9 +/- 10.3 years old) and prevalence of female gender (28% versus 4%) were significantly different between the group of patients with a small body surface area and the group with a large body surface area, respectively. However, the prevalence of unstable angina, previous myocardial infarction, extent of coronary artery disease, and preoperative ejection fraction was not significantly different between the two groups. The mean number of distal anastomoses was 3.0 and 2.8, and the mean duration of aortic occlusion was 65.6 +/- 23.0 minutes and 59.5 +/- 21.7 minutes in the small and large body surface area groups, respectively (not significant). The mean free flow rate of the internal mammary artery was 65.6 +/- 16.8 ml/min in the small body surface area group and 78.0 +/- 21.6 ml/min in the large body surface area group (p less than 0.05). The diameters of the anterior descending and the circumflex arteries were significantly smaller in the small body surface area group. Two patients (4%) died within 30 days of operation and one patient died later in the small body surface area group, whereas no death was noted in the large body surface area group (not significant). No significant differences were found in the incidence of aortic balloon pumping, perioperative myocardial infarction, and serious postoperative complications between the two groups. Symptomatic relief was equally good in both groups (92% and 96%). The patency rate of the internal mammary artery was 95% (42/44) in the small body surface area group and 100% (48/48) in the large body surface area group within 1 year, mean 2.3 +/- 2.4 months. In conclusion, internal mammary artery grafting can be performed safely and effectively even in patients with small body structure. Though the blood flow of the internal mammary artery and the size of the coronary arteries were smaller in patients with small body structure, excellent patency of the internal mammary artery graft and satisfactory symptomatic relief can be expected.

ATP and AMP were immediately converted into ADP by intact cells of Escherichia coli in the presence of Mg2+, while ADP was also rapidly converted into ATP and AMP under the same conditions. Adenylate kinase was released when E. coli cells were converted to spheroplasts by treatment with lysozyme-EDTA or osmotic shock. Adenylate kinase activities detected in the cytoplasm, periplasm and membrane fractions were approximately 58%, 36% and 6% of the total cellular activity, respectively. These results indicate that adenylate kinase in E. coli occurs in the periplasm as well as the cytoplasm.

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)

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.

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.

From November, 1984, to February 1987, internal mammary artery (IMA) and gastroepiploic artery (GEA) graftings to coronary arteries were performed in 65 patients. Of these patients, 58 unilateral IMAs, 6 bilateral IMAs, 2 GEAs were utilized. The hospital mortality was 3.2% but no cardiogenic death occurred. Fifty-eight (89%) patients became asymptomatic after surgery. Postoperative angiography performed from 1 to 3 months after operation showed excellent patency in 57 (96%) IMAs and 2 (100%) GEAs. On the other hand, the patency of saphenous vein graft done at the same period were 88%. GEAs were used for 2 reoperated cases and revealed good patency and relief of symptoms without surgical complication. Cavitron ultrasonic surgical aspirator (CUSA) was used to dissect IMA from the chest wall, which was useful to shorten the operative time. In conclusion, arterial grafts, such as IMA and GEA were thought to be excellent coronary bypass conduits even for the small Japanese patient.

Complementary DNA clones encoding a facilitative glucose transporter-like protein have been isolated from human small intestine and muscle cDNA libraries. This 509-amino acid protein has 65.3, 54.3, and 57.5% identity with the previously described human erythrocyte/HepG2, liver, and fetal muscle glucose transporter/transporter-like proteins, respectively. RNA blotting studies indicate that transcripts encoding this protein are very abundant in adult human skeletal muscle and subcutaneous fat. The adult skeletal muscle glucose transporter-like protein was expressed in vitro by cDNA-directed transcription and cell-free translation of the synthetic mRNA. The in vitro-synthesized protein reacted with a monoclonal antibody, 1F8, which recognizes the insulin-regulatable glucose transporter expressed in rat skeletal muscle, heart, and adipocytes. In contrast, in vitro-synthesized erythrocyte/HepG2 and fetal muscle glucose transporters did not react with 1F8. The high levels in adult skeletal muscle and subcutaneous fat of mRNA encoding the adult skeletal muscle glucose transporter and its specific reactivity with monoclonal antibody 1F8 suggest that this protein is the major insulin-regulatable glucose transporter expressed in skeletal muscle and other insulin-responsive tissues.

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.

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.

Polymorphism of 5' portion of the human insulin gene was examined in 188 unrelated Japanese subjects (49 normal, 71 with IDDM, and 68 with NIDDM) using restriction endonuclease analysis. Restriction fragments were classified according to the insertion size: Class 1 (600 base pairs), Class 2 (1300 base pairs), and Class 3 (2000 base pairs). We found a very high frequency of Class 1 alleles (96.8%) and a low frequency of both Class 2 (0.8%) and Class 3 alleles (2.4%) and that approximately 94% of the genotypes were Class 1/Class 1 homozygote. In addition, there was no correlation of allelic or genotypic frequency with NIDDM or IDDM. We conclude that length polymorphism of the human insulin gene cannot be a useful marker for diabetes in Japanese.

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.

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.

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.

Triple coronary artery bypass grafting utilizing the right gastroepiploic artery and both internal mammary arteries was performed successfully in a 37-year-old male, achieving primary myocardial revascularization. All grafts were in situ. The right gastroepiploic artery was anastomosed to the posterior descending artery. The right and left internal mammary arteries were anastomosed to the left anterior descending artery and the posterolateral branch, respectively. The postoperative angiogram showed good patency of all grafts. The patient recovered uneventfully with resolution of his angina pectoris.

Restriction fragment length polymorphism of the human insulin receptor gene was analyzed with a 4.2 Kb cDNA probe in Japanese normal subjects and Type 2 (non-insulin-dependent) diabetic patients. Restriction endonuclease Rsa I digestion showed polymorphism of the human insulin receptor gene, with a band at 6.7 Kb, 6.2 Kb or 3.6 Kb. The frequency of the 6.7 Kb band was less than that in Caucasians. Furthermore, 15% of all the Japanese subjects examined lacked a 3.6 Kb band, which is commonly found in Caucasians. We have also detected restriction fragment length polymorphism in the human insulin receptor gene by Pvu II or Stu I digestion. Although no significant association of restriction fragment length polymorphism with Type 2 diabetes was found in the present study, our results suggest that the restriction fragment length polymorphism in the human insulin receptor gene varies among ethnic groups, and that the restriction fragment length polymorphism linked to the human insulin receptor gene might be a useful marker for the linkage study of the genes located close to the human insulin receptor gene on chromosome 19.

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.

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.

The right gastroepiploic artery (GEA) was studied angiographically and histologically to determine its suitability for coronary artery bypass grafting. One hundred celiac angiograms demonstrated that the right GEA has the appropriate size (diameter less than 1.5 mm, 4%; 1.5 to 2 mm, 29%; more than 2 mm, 67%) and length (less than half of the greater curvature, 5%; more than half of the greater curvature, 95%; more than two-thirds of the greater curvature, 34%) for use as an in situ graft. A stenotic lesion of a GEA was observed in only 1 angiogram. Histological examination of a right GEA from 5 patients who had undergone gastrectomy demonstrated no evidence of arteriosclerosis. Encouraged by these results, we performed a coronary artery bypass reoperation utilizing an in situ right GEA graft in 2 women. Postoperative angiograms showed good patency of those grafts. The patients recovered well and were free from angina.

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.

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.

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.