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Biomedical subjects

T Endo

Publications and source records attributed to T Endo.

At least 613 records · Page 34Linked to original sources
PubMed1994

Portal venous invasion by pancreatobiliary carcinoma: diagnosis with intraportal endovascular US.

PURPOSE: To evaluate use of intraportal endovascular ultrasonography (IPEUS) in diagnosing portal venous invasion by pancreatobiliary carcinoma. MATERIALS AND METHODS: IPEUS was performed in 26 consecutive patients with pancreatobiliary carcinoma. All patients underwent surgery. IPEUS was performed intraoperatively in 20 cases and preoperatively in six. The sonographic criterion for detection of portal venous invasion was obliteration of the echogenic band of the portal vein. The IPEUS results were compared with those of computed tomography (CT) and arterial portography. RESULTS: Vascular invasion was confirmed with use of resected specimens in seven patients and operative findings in five patients. For diagnosis of portal venous invasion, the sensitivity, specificity, and overall accuracy of IPEUS were all 100%; respective values were 92%, 64%, and 77% for angiography and 50%, 79%, and 65% for CT. CONCLUSION: IPEUS allows detection or exclusion of early invasion of the portal venous wall by pancreatobiliary carcinoma.

Aged↗
PubMed1994

Relation of principal components of ECG maps to loci of wall motion abnormality in old myocardial infarction.

The purpose of this study was to examine the correlation between body surface potential distribution and the extent of abnormally contracting segments (ACS) of the left ventricle in patients with old myocardial infarction (MI). Body surface potential distribution was quantitatively analyzed using principal component analysis. The first six principal components were extracted from data set obtained from both 25 normal subjects and 100 patients. The z scores (principal component weights) were calculated in a time domain at every 4 or 8 ms in another 81 patients with previous MI. In anterior MI, the second z scores on T wave and the fourth z scores on QRS complex were significantly lower in the presence than in the absence of ACS at the lateral wall. In inferior MI, the first z scores on QRS complex, the second on T wave, and the third on both Q and T represented significant differences between the presence and the absence of ACS at the posterior wall. Minute differences in the extent of ACS were sensitively and noninvasively detected on z scores of principal components.

Adolescent↗
PubMed1994

Effects of L-arginine on impaired acetylcholine-induced and ischemic vasodilation of the forearm in patients with heart failure.

BACKGROUND: Endothelium-dependent vasodilation in response to acetylcholine (ACh) and ischemic vasodilation during reactive hyperemia are attenuated in the forearm of patients with heart failure (HF). It has been shown that L-arginine augments endothelium-dependent vasodilation in healthy subjects. Thus, the aim of the present study was to determine if L-arginine improves endothelium-dependent and ischemic vasodilation in the forearm in HF. METHODS AND RESULTS: Forearm blood flow was measured by a strain-gauge plethysmograph in 20 patients with HF and in 24 age-matched control subjects (C). Resting forearm vascular resistance (FVR) was significantly higher in HF than in C (37 +/- 4 versus 22 +/- 2 U, P < .01). Intra-arterial infusions of ACh or sodium nitroprusside (SNP) at graded doses progressively decreased FVR in HF as well as in C. The magnitude of ACh-induced vasodilation was attenuated in HF (P < .01), whereas SNP-induced vasodilation was similar between the two groups. The minimal FVR during reactive hyperemia after 10 minutes of arterial occlusion was significantly higher in HF (n = 12) than in C (n = 12) (3.2 +/- 0.4 versus 2.1 +/- 0.1 U, P < .05). L-Arginine significantly augmented maximal vasodilation evoked with ACh and decreased minimal FVR during reactive hyperemia in HF (P < .01) but not in C. L-Arginine did not affect SNP-induced vasodilation in HF or C. CONCLUSIONS: Our results suggest that defective endothelial function may contribute to impaired ischemic vasodilator capacity in HF.

Acetylcholine↗
PubMed1994

Role of nitric oxide in reactive hyperemia in human forearm vessels.

BACKGROUND: The role of nitric oxide (NO) in reactive hyperemia (RH) is not well known. We investigated whether NO plays a role in RH in human forearm vessels by examining the effects of NG-monomethyl-L-arginine (L-NMMA), a blocker of NO synthesis, on reactive hyperemic flow. METHODS AND RESULTS: Forearm blood flow (FBF) was measured by strain-gauge plethysmography with a venous occlusion technique. The left brachial artery was cannulated for drug infusion and direct measurement of arterial pressure. To produce RH, blood flow to the forearm was prevented by inflation of a cuff on the upper arm to suprasystolic pressure for intervals of 3 and 10 minutes. After the release of arterial occlusion (AO), FBF was measured every 15 seconds for 3 minutes. Resting FBF was 4.3 +/- 0.3 mL.min-1.100 mL-1 before 3 minutes of AO and 4.1 +/- 0.6 mL.min-1.100 mL-1 before 10 minutes of AO. FBF increased to 32.3 +/- 1.9 and 38.2 +/- 3.1 mL.min-1.100 mL-1 immediately after 3 and 10 minutes of AO, respectively, and gradually decayed (n = 13). Intra-arterial infusion of L-NMMA (4 mumol/min for 5 minutes) decreased baseline FBF (P < .01) without changes in arterial pressure. L-NMMA did not affect the peak reactive hyperemic FBF after 3 and 10 minutes of AO. L-NMMA significantly decreased total reactive hyperemic flow (flow debt repayment) by 20% to 30% after 3 and 10 minutes of AO. Simultaneous infusion of L-arginine (a precursor of NO) with L-NMMA reversed the effects of L-NMMA. CONCLUSIONS: Our results suggest that NO plays a minimal role in vasodilation at peak RH but plays a modest yet significant role in maintaining vasodilation after peak vasodilation. Our results also suggest that reactive hyperemia in human forearms is caused largely by mechanisms other than NO.

Adult↗
PubMed1994

Role of nitric oxide in exercise-induced vasodilation of the forearm.

BACKGROUND: We wished to determine the role of NO in exercise-induced metabolic forearm vasodilation. METHODS AND RESULTS: Young healthy volunteers (n = 11) underwent static handgrip exercise (4 to 5 kg, 3 minutes). Forearm blood flow (FBF) measured by strain plethysmography increased from 4.1 +/- 0.7 mL.min-1.100 mL-1 at rest to 9.8 +/- 1.2 mL.min-1.100 mL-1 immediately after exercise and gradually decreased thereafter. Exercise was repeated after intrabrachial artery infusion of NG-monomethyl-L-arginine (L-NMMA) at 4.0 mumol/min for 5 minutes. L-NMMA did not alter blood pressure and heart rate. L-NMMA decreased FBF at rest to 2.9 +/- 0.4 mL.min-1.100 mL-1 (P < .01), peak FBF immediately after exercise to 7.2 +/- 0.7 mL.min-1.100 mL-1 (P < .01), and FBF during the mid to late phase of metabolic vasodilation (P < .01). Calculated oxygen consumption during peak exercise was comparable before and after L-NMMA. Intra-arterially infused L-arginine (10 mg/min, 5 minutes) reversed the inhibitory effect of L-NMMA. To determine the effect of the decrease in resting FBF on exercise-induced hyperemia, we normalized FBF after exercise by resting FBF. The percent increases in FBF after exercise from resting FBF were similar before and after L-NMMA. Furthermore, we examined the effect of intra-arterially infused angiotensin II on FBF at rest and after exercise (n = 7). Angiotensin II decreased FBF at rest from 3.1 +/- 0.3 to 1.8 +/- 0.3 mL.min-1.100 mL-1 (P < .01), peak FBF after exercise from 8.1 +/- 0.5 to 5.6 +/- 0.5 mL.min-1.100 mL-1 (P < .01), and FBF during the mid to late phase of metabolic vasodilation. The effects of L-NMMA and angiotensin II on FBF at rest and exercise were similar. CONCLUSIONS: Our results suggest that L-NMMA decreased FBF after exercise largely by decreasing resting FBF. These results suggest that NO may not play a significant role in exercise-induced metabolic arteriolar vasodilation in the forearm of healthy humans.

Adult↗
PubMed1994

Nitric oxide influences neuronal activity in the nucleus tractus solitarius of rat brainstem slices.

Nitric oxide (NO) is shown to be synthesized in the central nervous system as well as in vascular endothelial cells. However, the physiological role of NO in cardiovascular regulation in the central nervous system remains unclear. The present study examines whether NO plays a role in the regulation of neuronal activity in the nucleus tractus solitarius (NTS). Single-unit extracellular recordings were obtained from NTS neurons in slices (400 microns) of the rat brainstem, which had spontaneous discharges at a frequency of 0.5 to 3 spikes per second. Eighty-one neurons were tested for sensitivity to L-arginine, which is the physiological precursor of NO. L-Arginine (10(-7) to 10(-4) mol/L) increased neuronal activity dose dependently in 33 (40.7%) of 81 neurons tested, but D-arginine (10(-5) mol/L) did not. The neurons that responded to L-arginine responded to glutamate as well. NG-Monomethyl-L-arginine (10(-5) to 3 x 10(-5) mol/L), an inhibitor of the formation of NO, dose-dependently blocked increases in the neuronal activity evoked with L-arginine (10(-5) mol/L). Hemoglobin (1.5 mg/L), a trapper of NO, and methylene blue (10(-5) mol/L), an inhibitor of guanylate cyclase, also blocked increases in the neuronal activity evoked with L-arginine (10(-5) mol/L). Sodium nitroprusside (SNP, 10(-5) to 10(-4) mol/L), which spontaneously produces NO, increased the neuronal activity in the neurons that responded to L-arginine. SNP did not alter the neuronal activity of the neurons that did not respond to L-arginine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Purification and characterization of arginine amidinohydrolase from Bacillus brevis TT02-8.

A bacterial arginase was purified to homogeneity from a strain of Bacillus brevis. The native enzyme, with an estimated MW of 143,000, migrated on SDS-PAGE as a single polypeptide of estimated MW of 33,000. The enzyme, highly specific to L-arginine, showed the maximum activity at pH 11.0 in the presence of Mn2+ ions and the pI was 4.8 by isoelectric focusing. The enzyme activity was increased significantly by the addition of Mn2+, Ni2+, or Co2+ ions, and inhibited potently by chemicals such as HgCl2, N-bromosuccinimide, or glutathione. The Kms for L-arginine and L-canavanine were 0.69 and 22.2 mM, respectively. The enzyme was inhibited competitively by gamma-guanidinobutyric acid, and non-competitively by L-lysine, L-ornithine, creatine, blasticidin S, and edeine B1. Analysis of the N-terminal amino acid sequence of the purified bacterial enzyme found 33-36% homologies with the Agrobacterium, yeast, rat, and human enzymes.

Amino Acid Sequence↗
PubMed1994

Simplification of superovulation induction by using polyvinylpyrrolidone as a solvent for FSH in rabbits.

With a view to simplify the method of inducing superovulation in rabbits, polyvinylpyrrolidone (PVP) was used as a solvent for follicle-stimulating hormone (FSH). As a result, it became clear that more than the equivalent number of ovulation points and fertilized ova that are obtainable by the conventional six injections of FSH were able to be obtained by only a single injection of FSH-PVP preparation. Inflammation or swelling of the tissue was not observed in the injection site or its vicinity. The results seem to enable simplification of superovulation induction by using PVP as a vehicle for FSH in rabbits. This finding could reduce injection distress to the animals and labor of the operator.

Animals↗
PubMed1994

Isolation of a cDNA whose expression is markedly increased in malignantly transformed FRTL cells and neoplastic human thyroid tissues.

We have cloned a cDNA whose mRNA levels are increased in malignantly transformed rat thyroid FRTL cells (FRTL-Tc cells). We constructed a cDNA library from FRTL-Tc cells in lambda gt10 and screened the cDNAs by differential plaque filter hybridization. Twenty-five thousand clones were screened and one cDNA (C140) was selected which corresponded to a mRNA whose expression was 5.8 times higher in FRTL-Tc cells than in FRTL cells. A 0.8 kb specific C140 mRNA was detected by Northern blot analysis of FRTL-Tc and FRTL mRNAs. The C140 cDNA was sequenced and found to encode a protein of 227 amino acids. We have found that C140 mRNA is conserved in human thyroid cells, but it is encoded by a smaller 0.7 kb transcript. C140 mRNA was highly expressed in neoplastic thyroid tissues and weakly in normal thyroid tissues in the same patients. Additionally, we found that C140 mRNA was also increased in the thyroid tissue of a patient with Graves' disease. These results suggest that C140 expression might be higher in rapidly growing thyroid cells than in normal cells, and might provide a new aspect for the study of thyroid tumours.

Amino Acid Sequence↗
PubMed1994

Desensitization and internalization of a thyrotrophin receptor lacking the cytoplasmic carboxy-terminal region.

To understand the functional significance of the carboxy-terminal half of the intracellular region of the human TSH receptor (hTSHR), a mutant hTSHR lacking amino acids from the carboxy-terminal to His726 was constructed. Wild type hTSHR cDNA and truncated hTSHR cDNA were subcloned into a eukaryotic expression vector, pRc/CMV, and transfected into Chinese hamster ovary cells to obtain cell lines which stably expressed hTSHRs at high levels. This allowed us to observe highly efficient coupling of hTSHR and adenylyl cyclase as well as desensitization and internalization of hTSHR. Despite the differences in potential phosphorylation sites and internalization signals, dose-dependent stimulation of adenylyl cyclase by TSH, TSH-dependent desensitization and the rate of hTSHR internalization were similar for wild type and truncated hTSHRs. We conclude that the carboxy-terminal half of the intracellular region of hTSHR does not have a major functional role in TSH-dependent signal transduction.

Amino Acid Sequence↗
PubMed1994

Thermal- and photo-polymerization of (meth) acrylates containing a spiro ortho ester moiety and the properties of poly[(meth)acrylate]s.

The syntheses and polymerizations of acrylate (ASOE) and methacrylate (MASOE) containing spiro ortho ester moieties were carried out and the properties of the polymers obtained were investigated. The ring-opening reaction of the spiro ortho ester groups proceeded well during heat polymerization (HC) with the ionic initiators (BSS and HPSS). However, a small amount of unreacted carbon-carbon double bond was observed in the polymers obtained. Not only vinyl polymerization but also a small amount of ring-opening reaction took place during polymerization with radical initiators (BPO, AIBN, DTB and CQ). The poly-(MASOE)s obtained by HC with BSS, BSS/AIBN and BSS/BPO were plastic like polymers. Low volume shrinkage was observed during HC and UVLC of ASOE and MASOE with ionic initiators. These shrinkages were smaller than those of conventional methacrylate.

Acrylates↗
PubMed1994

[Changes of plasma endothelin level in the early post-renal transplantation period].

Endothelin (ET) has been suggested to be involved in acute graft rejection of kidney transplantation and cyclosporin A (CsA) nephrotoxicity. For clarification of the pathophysiological role of ET in the early post-transplantation period, plasma endothelin-1 (ET-1) was measured by specific radioimmunoassay in renal transplant recipients, patients on maintenance hemodialysis (HD) and healthy volunteers. Twelve transplant recipients were used in this study, 8 of whom were living related subjects and 4 cadaver. Plasma ET-1 and graft function were measured each day, from 1 day prior and 7 days following transplantation and every week up to 5 weeks postoperatively. Plasma ET was measured in 20 other transplant recipients with stable function (serum creatinine < or = 1.8 mg/dl), 20 maintenance HD patients with no residual renal function and 6 healthy volunteers. Mean plasma ET-1 was 13.0 +/- 4.5 pg/ml in 20 recipients with stable graft function, 21.7 +/- 6.5 in 20 HD patients and 1.5 +/- 0.4 in healthy volunteers. These differences are statistically significant (p < 0.02). Plasma ET-1 showed significant decrease from 21.8 +/- 7.2 pg/ml prior to transplantation to 12.8 +/- 4.0 when urinary output reached more than 1000 ml in living and cadaveric transplantation subjects. All three acute vascular rejections clearly indicated histologically increased plasma ET-1 accompanied by an increase in serum creatinine. A significant positive liner correlation was noted between plasma ET-1 and serum creatinine during the first week following living transplantation. Two patients with clinically and histologically suspected CsA nephrotoxicity showed transient increase in plasma ET-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Effects of osmotic agents for cold kidney preservation].

The beneficial effect of UW solution may result from its ability to prevent tissue edema during cold storage. This study was conducted to determine which impermeant was effective in this regard during cold storage of a rat kidney in solution. Functional and morphological studies were made on a rat isolated perfused kidney (IPK) following 24 hour-cold storage in various tested solutions. Right nephrectomy was performed in 95 male rats by the method of Nishitsutsuji-Uwo et al and the kidney was perfused and stored at 4 degrees C for 24 hours as follows: glucose (194 mM) as a control, mannitol, sucrose, raffinose (140 mM in each), lactobionate (100 mM), raff + lact, hydroxyethyl starch 20, 40 (5%) with electrolyte composition essentially the same as that of Euro-Collins or UW solution. Kidneys stored for 24 hrs at 4 degrees C were perfused by the IPK apparatus. The perfusate flow rate was adjusted to maintain the renal arterial perfusion pressure at 100 mmHg. Raff, raff + lact or UW solution showed significantly higher fractional reabsorption of sodium than the control with no change in renal hemodynamics. The release of LDH into the perfusate was significantly less in raffinose than the control. Raffinose may thus be considered to function effectively as an impermeant for cold kidney preservation and molecule size would appear more important than negative charge for rat kidney preservation.

Animals↗
PubMed1994

[Thyroid stimulating activity of human TSH-R peptide antibody].

We have synthesized a TSH-R peptide (N-peptide) corresponding to the unique N-terminal segment (#29-57) and immunized it into rabbits. We found that the N-peptide antibody possessed thyroid stimulating antibody (TSAb) activity but lacked TSH-binding inhibitor immunoglobulin (TBII) activity. We then produced rabbit antibodies against the peptides corresponding to the mid-region (#172-202, C-peptide), the region near the transmembrane domain (#341-370, P-peptide), and the extracellular loops (#648-662, E1-peptide; #561-580, E2-peptide; #648-662, E3-peptide). All these peptide-antibodies showed also TSAb activities. These results suggest that the domains responsible for TSAb might span the entire extracellular components of the receptor and that even the extracellular loops are the candidates for the epitope against autoantibodies from Graves' patients.

Animals↗
PubMed1994

[Proliferation of pulmonary fibroblasts obtained from rats with bleomycin-induced pulmonary fibrosis and effects of rat rIL-1 alpha on this proliferation].

To clarify the mechanism of pulmonary fibrosis, the growth rate of fibroblasts obtained from bleomycin (BLM)-treated rats was compared with that of fibroblasts obtained from control rats. Proliferation of fibroblasts obtained from rats at 4 days after BLM instillation (BRF) was significantly more rapid than that of fibroblasts obtained from rats at 4 days after saline instillation (CRF), as assessed by cell counting and 3H-TdR incorporation. CRF and BRF were separated by the method of discontinuous Percoll gradients. Three fibroblast fractions of specific gravity (S.G.), S.G. < 1.036, 1.036 < or = S.G. < 1.050, 1.050 < or = S.G. < 1.062, were obtained. Percentages of the densest fibroblast fraction were 46.2 +/- 5.2 in BRF and 6.4 +/- 2.8 in CRF. The densest fibroblasts in BRF proliferated more rapidly than the least dense fibroblasts. Rat rIL-1 alpha suppressed the proliferation of CRF and BRF, dose dependently. These results suggest that an increase in the densest fibroblasts in the lung might correlate with BLM-induced pulmonary fibrosis and that IL-1 alpha suppresses the proliferation of pulmonary fibroblasts.

Animals↗
PubMed1994

Biological effects of diesel exhaust particles (DEP) on isolated cardiac muscle of guinea pigs.

Diesel engine-powered vehicles emit some 30 to 100 times more particles than do gasoline engine cars. We previously reported that diesel exhaust particles (DEP) could produce superoxide anions in an in vitro study. Furthermore, mice instilled intratracheally with DEP showed high mortality at low doses. The cause of death was lung edema with damage to the lung endothelial cells. In order to elucidate the mechanism of the onset of mortality induced by DEP, we examined the direct action of DEP on the isolated atrium of guinea pigs. A light-duty (2740cc), four cylinder diesel engine was used. The DEP were collected on fiberglass filter. DEP caused a negative inotropic action that was followed by the cardiac arrest of the isolated left atrium. These actions were not inhibited by propranolol, atropine, verapamil, diltiazem, diphenhydramine, indomethacin, superoxide dismutase or catalase. The precise mechanism of cardiac arrest is unknown. However, these results suggest that cardiac toxicity induced by DEP might be involved in lung edema.

Animals↗