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Biomedical subjects

K Miwa

Publications and source records attributed to K Miwa.

At least 235 records · Page 13Linked to original sources
PubMed1994

Variable responses of highly stenotic coronary arteries and collateral circulation to intracoronary injection of nitroglycerin in patients with chronic effort angina.

AIM: To assess the direct effects of nitroglycerin on coronary and collateral circulation, 31 consecutive patients with low exercise capacity resulting from chronic effort angina but who had not suffered previous myocardial infarction were investigated. METHODS: Rapid atrial pacing was used to induce myocardial ischemia, with the same pacing rate before and after an intracoronary injection of 50 micrograms nitroglycerin. Fifteen patients (group A) with an obstructed ischemia-related coronary artery (IRCA) (TIMI flow grade 0 or 1), were injected with nitroglycerin into a major donor artery of the well-developed collateral circulation. Sixteen patients with patent IRCAs (TIMI flow grade 2 or 3) were injected with nitroglycerin into the IRCA. These patients were subdivided according to the morphologic findings of the stenosis in the IRCA: group B, nine patients with eccentric elliptical residual lumens, and group C, seven patients with circular residual lumens. RESULTS: In group A, 0.21 +/- 0.08 mV of pacing-induced ST-segment depression was consistently ameliorated to 0.08 +/- 0.05 mV after pretreatment with nitroglycerin (P < 0.0001). In group B, the extent of ST-segment depression was markedly improved from a basal value of 0.21 +/- 0.05 mV to 0.05 +/- 0.03 mV with nitroglycerin (P < 0.001). In contrast, in group C ST-segment depression remained unchanged despite pretreatment with nitroglycerin (0.21 +/- 0.04 mV to 0.21 +/- 0.05 mV, P = NS). CONCLUSION: These results indicate that the contribution of the dynamic stenosis of the IRCA to effort angina differs greatly among patients and depends on the morphologic findings of the stenosis in the IRCA, and also that collateral circulation responds effectively to intracoronary injection of nitroglycerin in all patients with a well-developed collateral circulation.

Adult↗
PubMed1994

Lymph node metastases from carcinoma of the gastric stump.

The incidence of metastases from gastric stump cancer to various regional lymph node stations was studied after meticulous node dissection in 87 patients, who had undergone curative resection. Fifty-five (63%) patients had microscopically involved nodes. The incidence of node metastases varied between 17% and 30% in the perigastric nodes (n 1), with the same incidence in second-station lymph nodes (n 2; nodes along the left gastric, common hepatic and splenic artery, or nodes at the splenic hilus) With respect to third-station lymph nodes (n 3), metastases in nodes in the hepatoduodenal ligament (No 12) and retropancreatic nodes (No 13) were found only in 2% and 8% of the cases, respectively, but there was a high incidence of metastases (14/54, 31%) in the nodes along the mesenteric root. The overall 5-year survival rate was 48% and those for n 1 and n 2 patients were 78%, and 41%, respectively. With regard to the third level lymph node station, no 5-year survivors were seen when there was nodal involvement in node station No. 12 or No. 13. However, involvement of nodes at the root of the mesentery was associated with a 5-year survival rate of 25%. These results suggest that resection of the second level lymph nodes station must be combined with total gastrectomy and distal pancreatectomy, and that the resection of the mesenteric root is very important in patients with a tumor invading the jejunum.

Female↗
PubMed1994

[A progress in the diagnosis of malignant lymphoma].

Malignant lymphoma is usually divided into Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) according to the biological characteristics. Although the exact nature of HD is still unclear, NHL is well known to be a neoplasm of monoclonal and malignant B- or T-lymphocytes. Nowadays, the classification of pathologic type in HD seems to be settled in the Rye classification. On the other hand, in NHL the LSG classification has been fixed routinely in Japan and the Working Formulation originating in the USA has been used internationally after some historical confusion. As a recent trend in lymphoma diagnosis, the introduction of immunological and molecular biological techniques has had an impact on the previous concept and classification of malignant lymphoma based mainly on morphological criteria. In this article, recent progress in the diagnosis of malignant lymphoma, mainly NHL, including the analysis of immunophenotype and immunogenotype (intragenic and intergenic gene rearrangement) is briefly described.

Female↗
PubMed1993

Effect of antrectomy and drug-induced achlorhydria on urinary excretion of N-terminal big gastrin immunoreactivity in rats.

Immunoreactivities of urinary N-terminal big gastrin and serum C-terminal gastrin were determined in intact and antrectomized rats by radioimmunoassay using two antisera specific for N- and C-termini of big gastrin, respectively. Gel filtration of urine extract from intact rat showed a single giant peak of N-terminal big gastrin immunoreactivity eluted in a later position than 1-17 gastrin-34, indicating that N-terminal peptides smaller than 1-17 gastrin-34 are excreted in urine. Serum C-terminal gastrin concentration in antrectomized rats was about one sixth that in intact rats. Urinary excretion of N-terminal big gastrin in antrectomized rats was about one sixth that in intact rats. 2 week treatment with E3810, a proton pump inhibitor, (40 mg/kg/day, s.c.) induced urinary excretion of N-terminal big gastrin in parallel with a marked increase in serum C-terminal gastrin concentration in intact rats. Antrectomy completely prevented both the increase in urinary excretion of N-terminal big gastrin and the elevation of serum C-terminal gastrin induced by administration of E3810. There was an excellent correlation between serum concentration of C-terminal gastrin and urinary excretion of N-terminal big gastrin. These results suggest that urinary N-terminal big gastrin, which mostly originates from the gastric antrum, is a useful indicator of gastrin secretion in the rat.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1993

Involvement of the vacuolar H(+)-ATPases in the secretory pathway of HepG2 cells.

The macrolide antibiotic concanamycin B is a highly selective inhibitor (IC50 = 5 nM) of the H(+)-ATPases of the vacuolar system. We have examined the effects of concanamycin B on the constitutive secretory pathway of the human hepatoma cell line, HepG2. In cells exposed to 10 nM concanamycin B, transport from the endoplasmic reticulum to the Golgi occurs at normal rates, as determined by pulse-chase analysis of endoglycosidase H-sensitive product in conjunction with subcellular fractionation experiments. However, intra-Golgi trafficking or Golgi to plasma membrane delivery is significantly impaired. A delay in the onset of secretion of the major secretory proteins, albumin, alpha 1-antitrypsin and transferrin is observed. Processing of N-linked glycans by sialyltransferases is inhibited, resulting in secreted glycoproteins which are modified less extensively. In view of the acidic pH of the trans-Golgi and the trans-Golgi network, these studies suggest that acidification by vacuolar ATPases is critical to achieving timely secretion and correct N-linked glycan modifications of proteins which follow the constitutive secretory pathway.

Albumins↗
PubMed1993

Long-term efficacy of heparin exercise treatment for patients with chronic effort angina: evaluation by exercise Tl-201 myocardial scintigraphy.

To determine the effects of heparin exercise treatment on the coronary collateral flow reserve, exercise thallium-201 myocardial perfusion images were obtained with the same work-load before and late after heparin exercise treatment (17 +/- 2 months, mean +/- S.E.). In six patients with stable effort angina, to develop the collateral circulation, treadmill exercise was performed 20 times for 2-3 weeks with pretreatment with a single intravenous dose of heparin (5000 IU). The coronary collateral flow reserve was measured quantitatively as a severity score by analysis of exercise thallium-201 myocardial perfusion images. The severity score was decreased from 11,976 +/- 1722 to 5531 +/- 1967 (P < 0.05) long after heparin exercise treatment. The ST segment depression at the time of peak exercise was also decreased from 0.15 +/- 0.02 mV to 0.05 +/- 0.02 mV. In an additional five medically treated patients, these indexes remained unchanged during 18 +/- 3 months of follow-up period. These findings demonstrate that the coronary collateral flow reserve is significantly enhanced with heparin exercise treatment. These preliminary results lend support for heparin exercise treatment as one of the possible therapeutic modalities for treating patients with chronic stable effort angina.

Aged↗
PubMed1993

Sulfhydryl oxidation induces calcium release from fragmented sarcoplasmic reticulum even in the presence of glutathione.

Alcian blue and plumbagin induced transient Ca2+ release from fragmented sarcoplasmic reticulum. Dithiothreitol (DTT) and glutathione (GSH) partially blocked Ca2+ release induced by these oxidizing compounds. Pretreatment of alcian blue and plumbagin with DTT or GSH for more than 1 min was required to abolish the ability of the oxidizing compounds to release Ca2+. Mg2+ and ruthenium red completely blocked alcian blue-and plumbagin-induced Ca2+ release. These results suggest that oxidation of sulfhydryls on Ca2+ release channels induces Ca2+ release even in the presence of GSH in situ.

Animals↗
PubMed1993

Kinetic changes and experimental carcinogenesis after Billroth I and II gastrectomy.

To determine the risk of gastric remnant cancer according to the type of surgical reconstruction, the distal two-thirds of the glandular stomach was resected in male Wistar rats, followed by gastroduodenostomy (Billroth I anastomosis) or gastrojejunostomy (Billroth II anastomosis). No carcinogens were given and the animals were killed 50 weeks after operation. No cancers developed in 22 rats undergoing Billroth I gastrectomy, but five of 24 with Billroth II anastomosis had adenocarcinoma (P < 0.05). All carcinomas were confined to the stoma. Animals with Billroth II anastomosis had a more advanced grade of mucosal atrophy at the stoma, with a higher incidence of cystic dilatation, submucosal adenocystic proliferation and pseudopyloric metaplasia (P < 0.05). Cell kinetics in the stomal mucosa after Billroth II gastrectomy showed an increased cell count in the proliferative zone, longer duration of S phase and increased cell cycle time (P < 0.05). These results suggest that Billroth II gastrectomy carries a greater risk of cancer than the Billroth I procedure.

Anastomosis, Surgical↗
PubMed1993

Effects of intracoronary injection of acetylcholine on coronary collateral circulation.

To clarify the effect of intracoronary injection of acetylcholine on coronary collateral circulation, acetylcholine (20 and 50 micrograms) was injected directly into the donor artery of 5 patients with rest angina who had angiographically demonstrable collateral channels. Coronary spasm was defined as severe vasoconstriction (> or = 90% of luminal diameter) with chest pain and/or ischemic ST-segment changes. The intracoronary injection of acetylcholine induced spasm in all the 5 patients. The site of spasm was collateral vessels in 3, and the recipient coronary artery in 2 of the 5 patients. The spasm resolved spontaneously without administration of nitroglycerin. The contralateral intracoronary injection of acetylcholine also induced diffuse coronary spasm in 4 patients. These findings indicate that collateral vessels and recipient coronary arteries of the collateral circulation are susceptible to acetylcholine. Impaired relaxation and vasospastic responses to acetylcholine presumably due to endothelial dysfunction in the collateral and recipient coronary vessels may explain, at least in part, myocardial ischemia in patients with a well-developed collateral circulation.

Acetylcholine↗
PubMed1993

Effects of intracoronary administration of nitroglycerin on contralateral intracoronary acetylcholine test results.

This study examined the question of whether intracoronary administration of nitroglycerin modifies contralateral intracoronary acetylcholine test results. Acetylcholine was injected separately into both left and right coronary arteries in 63 patients with coronary spastic angina. Acetylcholine (20 and 50 micrograms) was injected first into the coronary artery responsible for the documented regional ischemia during spontaneous or induced attacks, and then into the other coronary artery. Coronary spasm was defined as severe transient coronary artery vasoconstriction with chest pain and/or electrocardiographic ischemic ST-segment deviation. Spasm was induced in either coronary artery in 60 patients (95%) and in both coronary arteries in 23 patients (37%). The frequency of induced spasm was 67% (42 of 63) in the coronary artery first challenged by acetylcholine. The coronary artery spasm subsided with the intracoronary injection of nitroglycerin (250-750 micrograms) in 19 patients. In the second challenge of intracoronary acetylcholine injection into the contralateral coronary artery, coronary spasm was induced in 29 (66%) of 44 patients. This was done without intracoronary administration of nitroglycerin in the first challenge and in 12 (63%) of 19 patients who had been given intracoronary nitroglycerin. The sensitivity for spasm induced by intracoronary acetylcholine appeared to be unaffected by nitroglycerin. Coronary spasm with ST-segment elevation by intracoronary acetylcholine in the second challenge was significantly less frequent in the patients receiving intracoronary acetylcholine in the second challenge was significantly less frequent in the patients receiving intracoronary nitroglycerin (first: 89%, second: 26%, p < 0.05) as well as in those not receiving intracoronary nitroglycerin for the spasm in the first challenge (first: 52%, second: 13%, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1993

Transient terminal U wave inversion as a more specific marker for myocardial ischemia.

Transient U wave inversion can be caused either by regional myocardial ischemia or by an elevation of systemic blood pressure. The characteristics of U wave inversion during chest pain attacks in 21 patients with variant angina were compared with those observed in 38 patients with hypertension without apparent ischemic heart disease. Differentiation was possible according to the ECG phase in which U wave inversion appeared. U wave inversion was considered to be significant if there was a discrete negative deflection of more than 0.05 mV within the TP segment. U wave inversion proceeded to positive deflection of U wave in patients with hypertension without ischemic heart disease (initial U wave inversion). In contrast, inverted U wave occurred after positive U wave deflection during attacks in patients with variant angina (terminal U wave inversion). When cold pressor test was performed in patients with variant angina during treatment with calcium entry blockers, no patient had either anginal attacks or ischemic ST-segment deviation, but 9 of 21 patients (43%) had transient initial U wave inversion, which was followed by positive U wave deflection. U wave inversion can be classified as initial U wave inversion and terminal U wave inversion according to the phasic relationship to positive U wave deflection; the latter is observed in association with regional myocardial ischemia. The former seems to be related to elevated blood pressure rather than to myocardial ischemia.

Adult↗
PubMed1993

Importance of ischemic preconditioning and collateral circulation for left ventricular functional recovery in patients with successful intracoronary thrombolysis for acute myocardial infarction.

We studied the effects of myocardial ischemic preconditioning and preexistent collateral circulation on the preservation of left ventricular function in 30 patients who had successful intracoronary thrombolysis within 6 hours after the onset of a first acute anterior myocardial infarction. The existence of ischemic preconditioning was defined as the episode of recurrent ischemic chest pain within 4 hours before the onset of acute myocardial infarction. In 16 patients with ischemic preconditioning (group A), the left ventricular ejection fraction during the convalescence of myocardial infarction was 57% +/- 11% (mean +/- SD); regional wall motion in the infarct area was 13% +/- 9%. In 14 patients without ischemic preconditioning (group B), the left ventricular ejection fraction and regional wall motion in the infarct area were 46% +/- 9% and 5% +/- 9% (both p < 0.05 vs group A). Moreover, among group A patients, seven patients having a well-developed collateral circulation during the acute stage of myocardial infarction showed a more prominent improvement in regional wall motion in the infarct area compared with nine patients having poor or no collateral circulation (18% +/- 8% vs 9% +/- 7%, p < 0.05). These data indicate that ischemic preconditioning is effective for the preservation of left ventricular function in patients with successful intracoronary thrombolysis and that preexistent coronary collateral circulation potentiates this favorable effect of ischemic preconditioning.

Adult↗
PubMed1993

Magnetic resonance imaging of oral and maxillofacial angiomas.

Eleven patients with oral and maxillofacial angiomas (seven hemangiomas and four lymphangiomas) were evaluated with magnetic resonance imaging using a 0.2-T permanent system and spin-echo pulse sequences. These lesions typically had signal intensities that were iso T1-weighted, similar to muscle, and high T2-weighted, greater than subcutaneous fat. Nine tumors had well- or relatively well-defined margins, and seven cases had curvilinear structures of low signal intensities in the masses on T2-weighted images. It was impossible to distinguish hemangiomas from lymphangiomas on MR images. Our experience suggested that most angiomas of oral and maxillofacial regions present special characteristics on magnetic resonance images. It is thought that information obtained with magnetic resonance images can contribute significantly to the evaluation of the extent of these lesions.

Adolescent↗
PubMed1993

Importance of non-stenosed donor coronary arteries for collateral flow reserve.

To elucidate whether the presence of significant stenoses in donor coronary arteries compromises collateral flow reserve, coronary arteriography was performed in 22 patients with stable effort angina who had a complete obstruction in one of the major coronary arteries. The patients were divided into two groups according to the absence (group I: n = 11) or presence (group II: n = 11) of significant stenoses (> or = 75% stenosis of the luminal diameter) in donor arteries. After conventional cardiac catheterization, coronary arteriography was repeated before and during rapid atrial pacing. Coronary collateral circulation was evaluated by means of angiographic contrast appearance time (CAT) which was defined as the time (s) until the epicardial segments distal to the site of complete occlusion were opacified after the injection of contrast medium into the donor artery. The pressure gradient across the collateral circulation (mean aortic pressure minus left ventricular end-diastolic pressure) remained unchanged before and during rapid atrial pacing (group I: 95 +/- 14 vs. 99 +/- 15 mmHg; group II: 91 +/- 18 vs. 94 +/- 16 mmHg). Rapid atrial pacing decreased the contrast appearance time in group I from 1.73 +/- 0.34 to 1.47 +/- 0.37 s (P < 0.01), but was not changed in group II from 1.68 +/- 0.36 to 1.73 +/- 0.51 s (P = n.s.). It was concluded that coronary collateral circulation is further augmented in response to an increase in myocardial oxygen demand in patients with non-stenosed donor coronary arteries and significant stenoses in donor arteries compromise an increase in collateral blood flow.

Aged↗
PubMed1993

Relation between collateral channel filling and flow grade in recipient coronary arteries in patients with stable effort angina.

OBJECTIVES: The purpose of the present study was to elucidate the relation between the extent of perfusion of the ischemia-related coronary artery and the degree of visualization of the collateral circulation to the ischemic area. BACKGROUND: Because it is difficult to accurately assess coronary stenosis severity with standard angiographic techniques, the inclusion of flow grade in recipient coronary arteries would provide an additional perspective concerning the effect of the progression of atherosclerotic obstructive disease on the development of collateral circulation. METHODS: The coronary arteriograms of 54 consecutive patients with chronic effort angina without prior myocardial infarction were examined. Patients were classified into four groups according to the extent of perfusion of the ischemia-related coronary artery (Thrombolysis in Myocardial Infarction [TIMI] grade 0 to 3). The degree of angiographically demonstrable collateral circulation was also classified into four grades (collateral index 0 to 3). RESULTS: Eighteen patients had TIMI grade 0, 6 had grade 1, 13 had grade 2 and 17 had grade 3 perfusion. The collateral indexes of TIMI 0, 1, 2 and 3 groups were 2.7 +/- 0.7 (mean +/- SEM), 2.2 +/- 0.6, 1.2 +/- 1.1 and 0.4 +/- 0.9, respectively (p < 0.01 vs. TIMI 0, p < 0.05 vs. TIMI 1). CONCLUSIONS: These findings indicate that all patients with chronic effort angina have the potential for collateral development as a result of coronary artery narrowing, and the functional state of well developed collateral vessels may be primarily determined by the pressure gradient across the collateral network.

Aged↗
PubMed1993

A new method for assessment of collateral development after acute myocardial infarction.

OBJECTIVES: The purpose of this study was to test the hypothesis that the diameter of the recipient coronary artery of the well developed collateral circulation in patients with acute myocardial infarction increases because of the augmented intravascular pressure caused by subsequent collateral development. BACKGROUND: It is well known that collateral circulation develops after acute myocardial infarction. However, some patients have a well developed collateral circulation at the onset of infarction, which may limit the angiographic evaluation of further development of collateral circulation. METHODS: We measured the diameter of the donor and recipient arteries of the collateral circulation by means of a computer-assisted analysis system in seven patients with acute myocardial infarction who had a totally occluded infarct-related coronary artery during the acute and chronic stages of infarction. All coronary angiograms were obtained after the administration of sublingual nitroglycerin. The measurement was repeated immediately after (within 6 h) and late after (42 +/- 11 days) the onset of acute myocardial infarction. RESULTS: The diameter of the donor artery remained unchanged (1.32 +/- 0.98 vs. 1.42 +/- 1.12 mm). In contrast, the diameter of the recipient artery increased from 1.25 +/- 0.63 to 1.55 +/- 0.61 mm (p < 0.01). These changes in coronary artery diameter were associated with an improvement in regional myocardial wall motion at rest in infarct areas (6.7 +/- 7.0% vs. 13.6 +/- 10.7%, p < 0.05). CONCLUSIONS: These findings indicate that serial measurement of coronary artery diameter is useful for the evaluation of collateral development after acute myocardial infarction.

Aged↗