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Biomedical subjects

K Miwa

Publications and source records attributed to K Miwa.

At least 271 records · Page 15Linked to original sources
PubMed1992

Relationship between the preexistent coronary collateral circulation and successful intracoronary thrombolysis for acute myocardial infarction.

The purpose of this study was to evaluate whether the existence of coronary collateral circulation influences recanalization rates of intracoronary thrombolysis. The study population consisted of 85 consecutive patients undergoing intracoronary thrombolysis within 6 hours after the onset of the first acute myocardial infarction, all of whom had a complete occlusion of the infarct-related coronary artery. Intracoronary thrombolysis with high-dose urokinase (960,000 IU) was attempted at a rate of 24,000 IU/min. Of 18 patients (group A) who had good angiographic collateral circulation to the area perfused by the infarct-related coronary artery, the obstructed artery was recanalized to a residual luminal diameter stenosis of less than or equal to 90% (successful recanalization) in only five (28%). In contrast, of 67 patients (group B) with poor or no collateral circulation, recanalization was successful in 40 (60%) (p less than 0.05). Antegrade flow of infarct-related arteries was observed following thrombolysis in 12 (67%) of 18 group A patients and in 56 (84%) of 67 group B patients (p = NS). It was concluded that (1) the presence of collaterals correlates with the presence of high-grade stenosis; (2) the presence of collaterals correlates with the presence of high-grade stenosis; (2) the presence of collaterals is inversely related to the efficacy of thrombolytic therapy; and (3) the difference in successful recanalization rates observed between the two groups probably reflects the impact of underlying stenosis severity on the effectiveness of lytic therapy.

Adult↗
PubMed1992

Significance of preinfarction angina for preservation of left ventricular function in acute myocardial infarction.

The effect of preinfarction angina on the preservation of left ventricular function was evaluated with the use of cineventriculography in 37 patients who had either total or subtotal occlusion of the proximal left anterior descending coronary artery during the convalescent period of myocardial infarction. In 15 patients who had preinfarction angina more than 1 week before the onset of acute myocardial infarction (group A), the global left ventricular ejection fraction was 54 +/- 3% (SEM) and regional wall motion in the infarct area was 10 +/- 3%. In 10 patients who had preinfarction angina occurred within 1 week before the onset of acute myocardial infarction (group B), the left ventricular ejection fraction and regional wall motion in the infarct area were 42 +/- 3% and 1 +/- 2%, respectively. In 12 patients without preinfarction angina (group C), the left ventricular ejection fraction and regional wall motion in the infarct area were 38 +/- 3% and -1 +/- 2%, respectively. In groups B and C, both the left ventricular ejection fraction and regional wall motion in the infarct area were lower than those in group A (p less than 0.05). The collateral circulation at the onset of acute myocardial infarction was better in group A compared with groups B and C (p less than 0.05). Thus the collateral circulation, promoted by repetitive anginal episodes indicative of myocardial ischemia, causes the preservation of myocardial function.

Angina Pectoris↗
PubMed1992

Proliferation assay of human gastric remnant by bromodeoxyuridine and flow cytometry.

The cell kinetics of gastric epithelium were studied by bromodeoxyuridine (BrdU) and flow cytometry in seven patients with remnant stomachs reconstructed with a Billroth type II procedure and in 25 patients with whole stomachs. Each patient received an intravenous injection of BrdU (200 mg/m2) 6 hours before surgery. Fresh specimens obtained from the lesser curvature, greater curvature, and stomal areas in the cases of remnant stomachs and from the antrum and fundus in the case of whole stomachs were studied. The BrdU labeling index was higher in the stomal area of the gastric remnant than in other areas, and DNA synthesis time was shortened in the stomal area of the gastric remnant (P less than 0.01) but not in other areas. The turnover time of the mucosa in the stomal area was 4.1 +/- 1.2 days, significantly shorter (P less than 0.01) than in other areas (7.6 +/- 2.3 to 8.2 +/- 1.2 days). The present study showed that the cell proliferation was extremely rapid in the stomal area of the gastric remnant, suggesting that this enhanced turnover of epithelial cells may assist in promoting carcinogenesis in the stomal area of the gastric remnant.

Aged↗
PubMed1992

The sensitivity of intracoronary injection of acetylcholine in inducing coronary spasm differs in patients with stable and unstable angina.

In an attempt to clarify the role of coronary artery spasm in the pathogenesis of unstable angina, acetylcholine (20 and 50 micrograms) was injected directly into the coronary arteries of 19 patients with unstable effort angina (group 1), 30 patients with unstable spontaneous angina (group 2), and 15 patients with stable effort angina due to coronary artery organic stenosis (greater than or equal to 75%) (group 3). Coronary spasm was defined as severe vasoconstriction (greater than or equal to 90% of luminal diameter) with chest pain and/or ischemic ST-segment changes. Intracoronary injection of acetylcholine induced spasm of at least one coronary artery in 19 patients (100%) of group 1 and 28 (93%) of group 2 but only 3 (20%) of group 3 (p less than 0.01). When acetylcholine was injected into the left and right coronary arteries separately, multivessel spasm (spasm of both coronary arteries) was induced in 5 of 12 (42%) patients of group 1 and in 9 of 23 (39%) patients of group 2. In contrast, intracoronary acetylcholine did not cause multivessel coronary spasm in any of 15 patients of group 3 (0%). These results suggest that coronary arteries in patients with unstable effort angina as well as spontaneous angina are susceptible to spasm and that coronary artery spasm may be responsible at least in part for the genesis of attacks in these patients.

Acetylcholine↗
PubMed1992

A CHO strain producing high-level human IL-6 with the 3' deletion construct.

A Chinese Hamster Ovary (CHO) strain producing high-level human interleukin 6 (IL-6) was obtained, by introduction of the IL-6 cDNA from which the 3' AU-rich region was deleted. The IL-6 mRNA of this strain was stable. The productivity was more than 15 times higher than the previously obtained clone, which has intact IL-6 cDNA in the same expression vector. This strain produced IL-6 at a high level of 30 micrograms ml-1 in batch culture, or a continuous 20 micrograms per 10(6) cells per day in microcarrier cultivation.

Animals↗
PubMed1992

Production of monoclonal antibodies specific to major allergens of Cryptomeria japonica pollen.

Monoclonal antibodies (MAbs) directed against Cryptomeria japonica pollen antigen (CPAg) were prepared. CPAg was precipitated with these MAbs and both MAbs CPA7 (IgG2a) and CPA9 (IgG1) recognized two major glycoproteins (m = 41 kDa and 46 kDa) of CPAg. MAb CPA7 or CPA9 was coupled to CNBr activated sepharose and affinity purification of the major allergen of CPAg from the crude extract was performed. The affinity purified CPAg bound IgE antibody present in patients with Cedar pollinosis.

Allergens↗
PubMed1992

Duodenal reflux through the pylorus induces gastric adenocarcinoma in the rat.

We investigated whether duodenal reflux through the pylorus is involved in the development of gastric cancer. Male Wistar rats weighing 230-250 g were subjected to three types of operative procedures: (i) allowing reflux through the pylorus; (ii) allowing reflux through a gastrojejunal stoma; and (iii) gastrotomy. No carcinogens were given, and the animals were killed 50 weeks after surgery. No cancers were detected in any of the 18 animals with gastrotomy. In contrast, seven (41%) of 17 animals with reflux through the pylorus and four (31%) of 13 animals with reflux through the stoma had adenocarcinoma. Differences in the incidence between both reflux groups and the gastrotomy group were significant (P < 0.01 and P < 0.05 respectively). All of the adenocarcinomas developed in the pyloric mucosa near the pylorus in the animals with reflux through the pylorus, and in the oxyntic mucosa near the stoma in those with reflux through the stoma. Adenocarcinomas appeared as a polyploid mass with or without slight central erosion. Most of the adenocarcinomas were of the well-differentiated tubular type, and the others were of the mucinous type. No differences in either the histologic type or depth of invasion of the adenocarcinoma were recognized between the two duodenogastric reflux groups. Precancerous or paracancerous lesions, such as adenoma, adenocystic proliferation, and stomal pseudopyloric metaplasia, were more frequently found in the same region as the adenocarcinomas. These findings suggest that duodenogastric reflux in the rat has potent carcinogenic activities not only in the oxyntic mucosa through the stoma, but also in the pyloric mucosa through the pylorus.

Adenocarcinoma↗
PubMed1992

Inflammatory pseudotumor of the spleen. Report of a case with an immunohistochemical study.

A 81-year-old Japanese man with a splenic inflammatory pseudotumor is described. The pseudotumor was unchanged in size after one year of observation. Macroscopically, the lesion was a firm well-circumscribed 5.5 x 5 x 5 cm mass showing a yellowish-white cut surface. Histologically, it was composed of abundant mixed inflammatory infiltrates, predominantly UCHL-1(+) T and L26(+) B lymphocytes, plasma cells containing various immunoglobulin subtypes, and S-100 protein(+), and lysozyme and NCA(+) histiocytes, with a sclerotic stroma. Small numbers of eosinophils, neutrophils and foamy macrophages were admixed. The patient has remained disease-free for 14 months after splenectomy. Only ten splenic inflammatory pseudotumors have been reported in the literature. This paper adds an additional case, together with details of immunohistochemical polyclonality of each inflammatory cell population, confirming that this disease is a nonspecific inflammatory change.

Aged↗
PubMed1992

Permeability and Mg2+ blockade of histamine-operated cation channel in endothelial cells of rat intrapulmonary artery.

1. In the cell-attached and inside-out patch-clamp experiments using undispersed endothelial cells of the rat intrapulmonary artery, the majority of channels were cation selective. 2. Under physiological ionic conditions, the I-V relationship for the inward currents fell to -80 mV and the slope conductance was 22.5 pS. There was an inward rectification and the outward currents were smaller than the inward currents. 3. Under symmetric high-K+ conditions, the slope conductance for the inward currents was 26.4 pS and the inward rectification was observed when the high-K+ solution contained 1 mM-Mg2+. The channel activity was weakly voltage dependent at negative membrane potentials, while it was much enhanced at positive potentials. 4. The channel activity did not depend on intracellular Ca2+ concentrations. 5. Mg2+ was not only impermeant, it also blocked this channel in a voltage-dependent manner and rectifications appeared in the I-V relationship. Mg2+ blocked the channel from both sides of the membrane. 6. Ca2+ permeated this channel and the permeability ratios calculated from the reversal potentials using the constant-field theory were; PK:PNa:PCa = 1:1:15.7. 7. Histamine but not acetylcholine applied to the pipette activated this channel. Guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) applied to the intracellular surface of the patch did not mimic the effect of histamine. 8. Thus, in the endothelial cell membrane of the rat intrapulmonary artery, there exists a cation channel which is selective to Ca2+ but also permeable to Na+ and K+. This channel has inward rectifying properties, possibly due to intracellular Mg2+. Histamine, but not acetylcholine, activates this cation channel to elevate endothelial [Ca2+]i.

Acetylcholine↗
PubMed1992

Biphasic changes (initial increase and late decrease) in coronary sinus venous oxygen saturation during anginal attacks induced by intracoronary acetylcholine in patients with variant angina.

In order to evaluate the effects of intracoronary acetylcholine on coronary resistance vessels, oxygen saturation in coronary sinus blood was continuously measured to compare its dynamic changes during intracoronary injection of acetylcholine in both patients with variant angina and control subjects. Group 1 consisted of 6 patients without coronary artery disease. Group 2 consisted of 10 patients with variant angina and spasm in the left anterior descending coronary artery. A fiberoptic reflection oximetry system was used for the continuous measurement of coronary sinus venous oxygen saturation. Acetylcholine (20 micrograms) was injected directly into the left coronary artery over 30 s. In the group 1 patients, coronary sinus venous oxygen saturation was increased from 39 +/- 2% (mean +/- SEM) to 54 +/- 3% at 30 s, continuously climbed to 70 +/- 3% at 60 s and then gradually decreased to 53 +/- 5% at 120 s after the initiation of intracoronary injection of acetylcholine. In contrast, in the group 2 patients, coronary sinus venous oxygen saturation was transiently increased from 39 +/- 2% to 56 +/- 4% at 30 s, reversed, decreased to 52 +/- 4% at 60 s and then rapidly decreased to 36 +/- 3% at 120 s with the onset of chest pain associated with electrocardiographic ischemic changes. Coronary arteriography during attacks demonstrated a total or subtotal occlusion of the left anterior descending coronary artery due to severe spasm in all of the 10 patients. The extent of increases in coronary sinus venous oxygen saturation at 30 s after acetylcholine injection was not significantly different between the two groups (group 1: 15 +/- 4%, group 2: 17 +/- 3%). Heart rate, blood pressure and rate-pressure product were essentially unchanged at 30 s after intracoronary injection of acetylcholine in both groups. These data suggest that in control adult humans, coronary blood flow was increased through dilatation of resistance vessels by acetylcholine, while in patients with variant angina, coronary blood flow was transiently increased by dilatation of resistance vessels, after which it was suddenly decreased by spasm of an epicardial artery induced by this agent. Relaxant responses to acetylcholine of coronary resistance vessels appear to be preserved well in patients with variant angina.

Acetylcholine↗
PubMed1992

Immunohistochemical detection of c-myc products in colorectal cancer and proliferative cell rate.

Expression of c-myc protein was studied immunohistochemically in colorectal cancers using a monoclonal antibody, MYC-1. Immunoblotting assays with cellular lysates demonstrated a band of the gene products at the level of 60 kDa. c-myc-protein-positive tumor cells were observed in 43 (43.4%) of 99 specimens of colorectal cancers. There was no significant correlation between the incidence of MYC-1-positive tumors and clinicopathological findings. The rate of MYC-1 proteins occurring in patients with liver metastasis was significantly higher than that in patients without the metastasis. The rate of occurrence of DNA polymerase-alpha-positive cells in MYC-1 protein-positive tumors was significantly higher than in MYC-1 negative ones. The results suggested that MYC-1 immunoreactivity might possibly be a useful prognostic marker of colorectal cancers.

Adenocarcinoma↗
PubMed1992

Rosette formation of impacted molar teeth in mucopolysaccharidoses and related disorders.

The radiographic features of the jaws in the mucopolysaccharidoses and related disorders (MPS) have been reviewed and three further cases are reported here, with particular reference to a novel dental anomaly, not previously described in detail, in two of them. The dental changes appear to be fully developed by the third decade and are characterized by bilateral multiple impacted molar teeth, which conglomerate in a single follicle to form a characteristic rosette of teeth. Rosetting was present only in relatively mature cases of MPS. However, it was also seen in the fourth patient, where we could not detect any other abnormal clinical or radiographic features. We therefore propose that since multiple rosetting of molar teeth can also occur in an isolated form, it is only suggestive of MPS.

Adolescent↗
PubMed1992

Pathogenesis of unstable angina with 0- or 1-vessel disease. Important role of coronary artery spasm.

In order to examine the possible role of coronary artery spasm in the pathogenesis of unstable angina, provocative testing for coronary spasm was performed in 43 patients with unstable angina who had 0- or 1-vessel disease. Coronary spasm was induced in 20 (65%) of 31 patients by hyperventilation testing (ST increases in 18, ST decreases in 2). Anginal attacks with either ST-segment elevation or ST-segment depression in patients without a significant organic stenosis were induced in 23 (55%) of 42 patients during treadmill exercise testing. Coronary artery spasm, showing severe (> or = 90%) vasoconstriction with angina and/or ischemic electrocardiographic ST-segment deviation, was also documented angiographically in 42 (98%) of 43 patients following intracoronary injection of acetylcholine. We conclude that dynamic coronary obstruction plays an important role in the genesis of attacks in patients with unstable angina who had 0- or 1-vessel organic coronary artery disease.

Acetylcholine↗
PubMed1992

Nitroarginine-sensitive and -insensitive components of the endothelium-dependent relaxation in the guinea-pig carotid artery.

In the guinea-pig carotid arteries, nitroarginine elevated the resting tension (greater than 3 x 10(-6) M) and enhanced the noradrenaline (NA)- and high-potassium (high-K, 29.6 mM) induced contractions (greater than 10(-7) M), in a concentration-dependent manner, with no significant change in the resting membrane potential and depolarizations elicited by NA or high-K. ACh (10(-6) M) relaxed the muscles precontracted with NA or high-K by 96 or 46% of the contraction, respectively. In the presence of nitroarginine (10(-5) M) for 1-3 h, the ACh-induced relaxation was reduced to 40 or 0% of the NA- or high-K-contractions, respectively. In tissues contracted with NA and exposed to nitroarginine, the ACh-induced relaxation changed from a sustained to a transient form. ACh relaxed the muscles to a similar extent, at any given level of tension, as elevated by different concentrations of NA to 1-3 times the level produced by 10(-6) M NA, either in the presence or absence of nitroarginine. ACh (greater than 10(-8) M) produced a transient hyperpolarization of the membrane, in an endothelium-dependent manner, and the responses were blocked by atropine (10(-6) M) or high-K solution, but not by NA or nitroarginine. We propose that 1) endothelium-derived hyperpolarizing factor (EDHF) is produced by pathways independent of the biosynthesis of endothelium-derived relaxing factor (EDRF), 2) the sustained release of EDRF maintains the muscle tone at a low level, and 3) the endothelium-dependent relaxation is produced by both EDRF and EDHF, and they elicit sustained and transient relaxations, respectively.

Acetylcholine↗
PubMed1992

[Serum sialyl-Tn antigen in colorectal cancer and its relationship to prognosis].

Serum sialyl-Tn antigen level was studied in 117 cases of colorectal cancer. The positive rates for serum sialyl-Tn antigen were 23.1% in primary colorectal cancer. There is a significant correlation between the positive rates of serum sialyl-Tn antigen and liver metastases, peritoneal dissemination, or lymph node metastases. The survival rate for patients with sialyl-Tn antigen positive sera was lower than those with sialyl-Tn antigen negative. Among patients who underwent curative operation, patients with sialyl-Tn positive sera gave a recurrence rate of 35.7%, while those with sialyl-Tn negative sera recorded a recurrence rate of 14.7%. There is no correlation between the positive rates of serum sialyl-Tn antigen and DNA ploidy pattern. Serum sialyl-Tn antigen levels may be a useful indicator in projecting the prognosis of colorectal cancer.

Antigens, Neoplasm↗
PubMed1992

[Study on correlation of hematogenous metastasis in advanced colorectal cancer with the morphological mode of tumor invasion in the pm layer].

We studied the influence of the morphological mode of tumor invasion in muscularis propria (pm) layer, in 177 patients who received resection for colorectal carcinoma that invaded beyond the pm layer. Tapering Index (TI = A/B) defined from the ratio between the length of tumor invasion on upper pm layer (A) and that on lower pm layer (B), TI value was significantly lower in cases with hematogenous metastasis than that in cases without hematogenous metastasis. Cases in which TI values were under 1.3 in colon cancer and 1.9 in rectal cancer had higher possibility of synchronous or metachronous hematogenous metastasis and poorer prognosis. Therefore, we suspected that TI value would be an important factor in prediction of hematogenous metastasis.

Adult↗