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Biomedical subjects

S Miki

Publications and source records attributed to S Miki.

At least 109 records · Page 6Linked to original sources
PubMed1993

Increased granulocyte/macrophage colony-stimulating factor production by mononuclear cells from peripheral blood of patients with bronchial asthma.

The in vitro production of granulocyte/macrophage colony-stimulating factor (GM-CSF) by mononuclear cells (MNC) from the peripheral blood of patients with bronchial asthma (BA) was examined by enzyme-linked immunosorbent assay (ELISA). GM-CSF concentrations in the media of MNC from patients with BA cultured with interleukin-2 (IL-2) was 80.2 +/- 52.0 pg/ml (mean +/- SE, n = 12), and that in cultures without a stimulant was 12.1 +/- 11.3 pg/ml. The GM-CSF concentrations in the media of MNC from patients with other diseases (n = 13) and from healthy volunteers (n = 6) cultured with or without IL-2 were less than 7.5 pg/ml (the minimum detectable value). The culture media of MNC from patients with BA demonstrated activities for stimulating the proliferation and survival of eosinophils, and these activities were partially inhibited by anti-GM-CSF antibodies. GM-CSF production by MNC of patients with BA treated with glucocorticoids was lower than that of MNC from untreated patients with BA, and it was inhibited by coculture with glucocorticoids in vitro. These results suggest that GM-CSF production by MNC is increased in patients with BA, is modulated by glucocorticoids, and may play an important role in the pathogenesis of BA.

Adult↗
PubMed1993

Factors that stimulate the proliferation and survival of eosinophils in eosinophilic pleural effusion: relationship to granulocyte/macrophage colony-stimulating factor, interleukin-5, and interleukin-3.

To investigate the mechanism of eosinophilia in patients with eosinophilic pleural effusions, we measured the activities of eosinophil colony-stimulating factor (Eo-CSF) and stimulating factor for eosinophil survival in the eosinophilic pleural fluids of six patients (two with tuberculous pleuritis, two with drug allergy, and one each with chronic eosinophilic pneumonia and pleuritis associated with rheumatoid arthritis). The number of eosinophil colonies formed by the pleural fluid of patients with eosinophilic pleural effusions significantly exceeded that of control patients with noneosinophilic pleural effusions (7.5 +/- 1.9 colonies/10(5) bone marrow cells, n = 6, versus 0.3 +/- 0.1 colonies/10(5) bone marrow cells, n = 6, P < 0.01). Similarly, eosinophil survival evaluated on day 4 of culture with pleural fluid of patients with eosinophilic pleural effusions significantly exceeded that of patients with noneosinophilic pleural effusions (83.9 +/- 9.8% versus 46.1 +/- 11.2%, P < 0.001). Both activities were inhibited mainly by anti-IL-5 antibody and partially by anti-GM-CSF antibody and anti-IL-3 antibody. Mononuclear cells obtained from eosinophilic pleural fluid released the activities of Eo-CSF and stimulating factor for eosinophil survival in vitro. These findings suggest that GM-CSF, IL-5, and IL-3 are important to eosinophil accumulation in pleural cavity as stimulators of proliferation and survival of eosinophils.

Adult↗
PubMed1993

Doppler sonographic measurement of phasic renal artery blood flow velocity in patients with chronic glomerulonephritis.

The phasic arterial blood flow velocity at the renal hilus was measured by Doppler sonography in 25 healthy subjects and 78 patients with chronic glomerulonephritis. Doppler velocity waveform was analyzed to give peak systolic velocity (S), end-diastolic velocity (D), resistive index (RI), and pulsatility index (PI). Creatinine clearance correlated with S (r = 0.76), D (r = 0.80), RI (r = -0.74), and PI (r = -0.85). Color Doppler sonography facilitated the detection of blood flow and permitted the measurement of absolute blood flow velocity, which previously had been difficult to determine. These results suggest that renal arterial blood flow as detected by Doppler ultrasonography may be useful for noninvasive, direct, rapid, and simple evaluation of renal function, although various modifying factors also need to be considered.

Adult↗
PubMed1993

Metabolism of beta-muricholic acid in the hamster and prairie dog.

The metabolism of beta-muricholic acid was investigated in the prairie dog and the hamster. Intravenous infusion into bile fistula hamsters showed that beta-muricholic acid was extracted by the liver and secreted into the bile (> 85% in 1 h). Hepatic extraction of this compound and cholic acid in the prairie dog was not as rapid as in the hamster. In the bile of the prairie dog, most (93%) of the administered beta-muricholic acid was present as the taurine conjugate. In the hamster, 28% of infused beta-muricholic acid was secreted in unconjugated form, 43% as the taurine conjugate, and 22% as the glycine conjugate. In both species, the administered compound underwent little biotransformation. After intraduodenal injection of [6 alpha-3H]-labeled beta-muricholic acid into bile fistula hamsters, the bile acid was rapidly secreted into the bile; more than 80% of the administered radioactivity was recovered in 3 h. In the prairie dog, biliary recovery after intraduodenal administration of either beta-muricholic acid (43% in 3 h) or cholic acid (22% in 3 h) was slower than in the hamster. After intragastric administration, more than 80% of beta-muricholic acid was recovered unchanged in feces of both animal species.

Animals↗
PubMed1993

Complete elimination ('cure') of progressively growing intraocular tumors by local injection of tumor-specific CD8+ T lymphocytes.

PURPOSE: The purpose of this study was to examine if anterior chamber tumors could be eliminated by adoptive immunotherapy. METHODS: Precursor T cells were recovered from lymph nodes draining subconjunctival space or anterior chamber tumors and restimulated in vitro to obtain fully functional tumor-specific CD8+ cytolytic T cells. RESULTS: Subconjunctival space tumor-derived cytolytic T cells eliminated tumors completely when injected simultaneously into the eye with the tumor cells, or when the anterior chamber injection was delayed for up to 3 days. In vitro restimulated cytolytic T cells obtained from lymph nodes draining progressively growing anterior chamber tumors were as effective as those obtained from lymph nodes draining subconjunctival space tumors, indicating that mice with anterior chamber tumors possess precursor cytotoxic T cells with the potential to differentiate into cytolytic T cells capable of eliminating intraocular tumors. By determining the frequency of tumor-specific cytolytic T cells in the effector cell inocula, it was estimated that cures of intraocular tumors are possible when the ratio of cytolytic T cells to tumor cells is less than 1:50, and the total tumor burden at the time of adoptive immunotherapy is less than 80,000 viable tumor cells. CONCLUSIONS: It was concluded that terminally differentiated, antigen-specific, cytotoxic T cells injected directly into an intraocular tumor site are capable of eliminating the tumor, and may represent a mode of ocular tumor immunotherapy in the future.

Animals↗
PubMed1993

Comparative evaluation of left ventricular performance after mitral valve repair or valve replacement with or without chordal preservation.

The clinical importance of preserving the chordae tendineae during mitral valve replacement was assessed by comparing the postoperative left ventricular performances in 68 patients who underwent mitral valve replacement (MVR) with complete chordal preservation (n = 19), conventional MVR (n = 25) or mitral valve repair (n = 24) and had full hemodynamic assessment before and after surgery. The pre- and postoperative left ventricular performances were analyzed using cineangiography, multiple-gated cardiac blood pool scintigraphy (MUGA), and echocardiography. In the early postoperative period, cineangiography revealed that the end-systolic volume index (ESVI) and the end-diastolic pressure were significantly higher in the conventional MVR group. The left ventricular ejection fraction was unchanged in the chordal preservation group, but was decreased in the mitral repair and conventional MVR groups. The end-systolic circumferential left ventricular wall stress (ESS) was significantly decreased in the chordal preservation and mitral repair groups, but was unchanged, and thus higher, in the conventional MVR group. The postoperative left ventricular contractility index (ESS/ESVI) was better in the chordal preservation than in the conventional MVR group. In the late postoperative period, both the left ventricular ejection fraction as measured by MUGA and the left ventricular fractional shortening as measured by echocardiography were significantly higher in the mitral repair and chordal preservation groups than in the conventional MVR group. This study supports the concept that the maintenance of continuity between the mitral annulus and the papillary muscles has a beneficial effect on postoperative left ventricular performance.

Adult↗
PubMed1993

Metabolism and choleretic activity of homochenodeoxycholic acid in the hamster.

The hepatic metabolism and the choleretic effect of homochenodeoxycholic acid, the C25 homologue of chenodeoxycholic acid, were investigated in the hamster. After intravenous administration of 3H-labeled homochenodeoxycholic acid into biliary fistula hamsters, more than 80% of the radioactivity was recovered in bile in 4 h. A relatively small proportion of homochenodeoxycholic acid was present in bile as the taurine (22%) or glycine (4%) conjugate. However, more than 70% of the administered compound was biotransformed into C23 bile acids. The major C23 metabolites in bile were norchenodeoxycholic acid (17%), tauronorchenodeoxycholic acid (33%), and a trihydroxy norbile acid (identified as 3 alpha, 5 beta, 7 alpha-trihydroxy-24-nor-5 beta-cholan-23-oic acid, 19%). Small amounts (< 5%) of sulfate(s) and glucuronide(s) were also detected. Homochenodeoxycholic acid, when infused intravenously into the hamster, produced a striking choleresis. The increase in bile flow after infusion of this compound was 6- to 7-times that induced by chenodeoxycholic acid. The apparent choleretic activity of homochenodeoxycholic acid, 181 microliters/mumol, was much greater than that of chenodeoxycholic acid, 11 microliters/mumol. In conclusion, homochenodeoxycholic acid induced a hypercholeresis of the same order of magnitude as norchenodeoxycholic acid, presumably because considerable proportions of this compound were degraded to the hypercholeretic norchenodeoxycholic acid via beta-oxidation in the liver.

Animals↗
PubMed1993

Bile acid sulfonates alter cholesterol gallstone incidence in hamsters.

The prevention of cholesterol gallstone formation by three bile acid analogs, sodium 3 alpha,7 alpha-dihydroxy-5 beta-cholane-24- sulfonate, sodium 3 alpha,7 beta-dihydroxy-5 beta-cholane-24-sulfonate and sodium 3 alpha,6 alpha-dihydroxy-5 beta-cholane-24-sulfonate, was examined in a hamster model of cholesterol cholelithiasis. Sodium taurochenodeoxycholate, sodium tauroursodeoxycholate and sodium taurohyodeoxycholate were studied simultaneously for comparison. Gallstones and cholesterol crystals were induced in 14 of 15 hamsters fed a bile acid-free, semipurified lithogenic diet containing 0.3% cholesterol and 4% butterfat for 6 wk. The addition of 0.1% sodium taurochenodeoxycholate and sodium tauroursodeoxycholate to the lithogenic diet had little effect on the formation of gallstones or biliary cholesterol crystals. In contrast, sodium 3 alpha,7 alpha-hydroxy-5 beta-cholane-24- sulfonate and sodium 3 alpha,7 beta-dihydroxy-5 beta-cholane-24-sulfonate, when fed at the same dose, prevented cholesterol gallstone formation significantly. Sodium taurohyodeoxycholate and sodium 3 alpha,6 alpha-dihydroxy-5 beta-cholane- 24-sulfonate inhibited cholesterol gallstone formation effectively. The cholesterol saturation index of bile was greater than 1.00 in all groups, with the exception of the group fed sodium 3 alpha,7 alpha-dihydroxy-5 beta-cholane-24-sulfonate. Liver and serum cholesterol levels tended to be lower in most of the groups that were fed bile acids. This effect was most pronounced in the animals receiving sodium taurohyodeoxycholate. At the end of the experiment, the administered sulfonate analogs were detected in gallbladder bile.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Development of left atrial thrombus after excellent mitral valvuloplasty for chronic severe mitral regurgitation].

We report two cases with chronic severe mitral regurgitation and atrial fibrillation in whom left atrial thrombus was detected by transesophageal echocardiography after excellent mitral valvuloplasty. The reason why thrombus developed after valvuloplasty is that preoperative severe mitral regurgitation made the left atrial blood less stagnant than it was after surgery. Thus, even when mitral valvuloplasty achieves excellent results in patients with severe chronic mitral regurgitation and atrial fibrillation, anticoagulation and left atrial appendage ligation should also be considered.

Aged↗
PubMed1993

Metabolism of sulfonate analogs of ursodeoxycholic acid and their effects on biliary bile acid composition in hamsters.

The metabolism of sodium 3 alpha,7 beta-dihydroxy-5 beta-cholane-24-sulfonate and sodium 3 alpha,7 beta-dihydroxy-24-nor-5 beta-cholane-23-sulfonate was studied in hamsters. In bile fistula animals these sulfonate analogs of ursodeoxycholic acid were absorbed mainly from the terminal ileum and secreted rapidly into the bile without biotransformation or conjugation. After oral administration, the sulfonate analogs were excreted in the feces at the same rate as chenodeoxycholic acid and its metabolic products. The intestinal microorganisms transformed chenodeoxycholic acid largely into lithocholic acid; the sulfonate analogs were completely resistant to biotransformation. After a 2-week feeding period, the sulfonate analogs of ursodeoxycholic acid accounted for 24.0% and 16.9% of total biliary bile acids. These sulfonates did not affect the proportions of the natural bile acids in the bile, and the ratio of glycine-conjugated bile acids to taurine-conjugated bile acids was not altered by feeding the sulfonates. In contrast, when ursodeoxycholic acid was fed, the proportions of the natural bile acids and the glycine/taurine ratio were changed. These results suggest that the sulfonate analogs had no profound effect on endogenous bile acid metabolism and did not cause a depletion of the hepatic taurine pool during enterohepatic circulation. The sulfonates had no effect on intestinal cholesterol absorption and serum cholesterol levels.

Animals↗
PubMed1993

[The protective effect of continuous retrograde cerebral perfusion on the central nervous system during deep hypothermic systemic circulatory arrest].

Deep hypothermic circulatory arrest (DHCA) was introduced as an adjunct for operations involving aortic arch lesions in 1970's and has since been widely used. Profound hypothermia protects the brain and other vital organs by reducing metabolic rate. We initiated the use of continuous retrograde cerebral perfusion (CRCP) via the superior vena cava during DHCA in 1987. We studied 15 patients who required DHCA and CRCP during repair or replacement of the aortic arch. CRCP times ranged from 11 to 78 (mean +/- S.D.; 37.3 +/- 21) minutes, and minimal nasopharyngeal temperatures ranged from 13.7 to 25 (17.7 +/- 2.6) degrees C. Two patients died one month postoperatively due to preoperative disease. Three patients, who were in shock preoperatively due to cardiac tamponade, developed acute renal failure postoperatively. The remaining patients were weaned from the respirator by the 2nd postoperative day. No patient had CRCP-related complications. During CRCP, the partial pressure of oxygen (PO2), saturation of oxygen (SO2), and oxygen content significantly decreased (p < 0.001), and the partial pressure of carbon dioxide (PCO2) and CO2 content significantly increased (p < 0.001) between retrogradely perfused blood and blood draining from the arch vessels. These results most probably reflected that the aerobic metabolism of the brain was maintained by CRCP while the central nervous system was maintained in a hypothermic state, with oxygen and substrate availability, wash-out of metabolites, and buffering capacity and oncotic pressure of the blood maintained. This technique offers the potentials of sufficient metabolic support to the brain during DHCA and prolonged safe time limits of DHCA.

Adult↗
PubMed1992

Expression of scavenger receptors on renal cell carcinoma cells in vitro.

Messenger RNAs and proteins of scavenger receptor thought to be macrophage specific protein were expressed in renal cell carcinoma (RCC) cells in vitro. Acetyl LDL was taken up into RCC cells and promoted the production of interleukin-6 (IL-6), an in vitro autocrine growth factor to proliferate the cells. These results suggested that RCC cells might have a scavenger pathway which has not yet been demonstrated except for macrophages.

Blotting, Northern↗
PubMed1992

Slope of the end-systolic pressure-volume relation derived from single beat analysis is not always sensitive to positive inotropic stimuli in humans.

Single beat estimation of the slope of the end-systolic pressure-volume relation assumes symmetric left ventricular pressure increase and decay and requires extrapolation of peak isovolumic developed pressure (Pmax) from the left ventricular pressure curve of an ejection contraction. To test the sensitivity of this slope to positive inotropic stimuli, biplane cineangiocardiography and simultaneous high-fidelity left ventricular pressure measurements were performed in 50 patients with heart disease. The end-systolic pressure-volume relations were assessed under baseline conditions and during norepinephrine infusion (n = 19) or after postextrasystolic potentiation (n = 24), or both (n = 7). Norepinephrine did not change left ventricular end-systolic volume despite significant elevations of end-systolic pressure. Postextrasystolic potentiation significantly decreased end-systolic volume in association with an unaltered left ventricular end-systolic pressure. The potentiation significantly decreased the pressure half-time of contraction, an index of the speed of the left ventricular pressure increase, while it increased the pressure half-time of relaxation, an index of the speed of the pressure decline, indicating asymmetric pressure increase and decay. The slope of the end-systolic pressure-volume relation increased from 3.3 to 4.4 mm Hg/ml/m2 (p less than 0.001) during norepinephrine infusion. In contrast, despite an augmented contractility, the slope decreased significantly from 3.2 to 2.4 mm Hg/ml/m2 (p less than 0.0001) after the potentiation. The slope showed a high correlation with Pmax (r = 0.86, p less than 0.0001, n = 107). Thus, the slope of the end-systolic pressure-volume relation derived from single beat analysis is not always sensitive to inotropic interventions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Spin-echo M-mode NMR imaging.

A nuclear magnetic resonance (NMR) imaging and display method for the observation of the continuous motion of objects is presented. By modifying a line scan technique, the spin-density distribution along a line is displayed in succession. Although spatial information is limited to only one dimension, the motion of the object is recorded at intervals of 55 ms by using a commercially available NMR imaging system. In a phantom study, this method yielded accurate velocity measurements along a single axis. When the method was applied to the human chest, an image analogous to that of M-mode echocardiography was obtained. This method, which can be called spin-echo M-mode NMR imaging, approaches the functional analysis of cardiac wall motion in regions where echocardiography is not possible. The effects of respiratory motion on the left ventricular wall were recorded in addition to its intrinsic contractile motion in an image obtained along a line parallel to the cranio-caudal axis of the body. The advantages of this method to assess cardiac wall motion in a patient with an arrhythmia were also demonstrated.

Atrial Fibrillation↗
PubMed1992

Palmitic acid enhances cholesterol gallstone incidence in Sasco hamsters fed cholesterol enriched diets.

In an established hamster model of cholesterol cholelithiasis, a semipurified lithogenic diet containing 4% butterfat and 0.3% cholesterol leads to the production of cholesterol gallstones in only 50-60% of animals after a 6-wk feeding period. The purpose of this study was to investigate whether gallstone incidence could be increased while feeding a nutritionally adequate diet of moderate cholesterol content. The semipurified lithogenic diet was modified as follows: (i) substitution of 1.2% palmitic acid for 4% butterfat, and (ii) varying the amount of dietary cholesterol from 0.0 to 0.3% with either butterfat or palmitic acid as the lipid component of the diet. Substitution of palmitic acid for butterfat produced a significantly higher incidence of cholesterol gallstones (94% vs. 53%). Palmitic acid also raised the incidence of gallstones when added to the 0.1% and 0.2% cholesterol diets as compared to butterfat: 0% vs. 44% and 50% vs. 81%, respectively. Gallstone incidence increased from 0% to nearly 100% when the cholesterol content of the palmitic acid diets was raised from 0.0% to 0.3%, indicating a dose response effect with respect to dietary cholesterol. Hamsters fed cholesterol-free diets did not form gallstones. Increased dietary cholesterol led to increased liver weight associated with a significant increase in liver cholesterol concentration. However, the palmitic acid groups had significantly lower liver cholesterol values than the corresponding butterfat groups. Serum and biliary cholesterol concentrations increased with increasing dietary cholesterol intake, but there were no differences between the butterfat and palmitic acid groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Dietary fat and fatty acids modulate cholesterol cholelithiasis in the hamster.

We tested two hypotheses, i) whether the type and the amount of fat in the diet will affect the formation of cholesterol gallstones in the hamsters, and ii) whether palmitic acid, a major fatty acid component of butterfat, can act as a potentiator of cholesterol cholelithiasis in the hamster. Young, male golden Syrian hamsters (Sasco) were fed a semipurified diet containing casein, corn starch, cellulose and cholesterol (0.3%) to which various types and amounts of fat (butterfat, olive oil, menhaden oil, corn oil) were added. All diets contained 2% corn oil to supply essential fatty acids to the growing hamsters. No deaths or illness occurred during the experiment. Animals fed the semipurified diet plus 4% butterfat (group 1) had a gallstone incidence of 63%. Replacement of butterfat with either olive oil, corn oil or menhaden oil prevented the formation of cholesterol gallstones entirely (groups 2-4). When total butterfat was increased from 4% to 8% (group 8), the incidence of cholesterol gallstones increased to 80%. Substitution of 4% olive oil (group 5), corn oil (group 6), or menhaden oil (group 7) for the additional 4% butterfat significantly reduced gallstones to 35%, 45% and 30%, respectively. The replacement of 4% butterfat with 1.2% palmitic acid gave the highest incidence of cholesterol gallstones (95%). These results suggest that butterfat (and one of its components, palmitic acid) intensifies gallstone formation in this model whereas mono- and polyunsaturated fats act as inhibitors of cholesterol cholelithiasis. A fatty acid, possibly palmitic acid, appears to act as lithogen in our model.

Animals↗
PubMed1992

Induction of coronary artery spasm by intracoronary acetylcholine: comparison with intracoronary ergonovine.

To investigate the mechanism of coronary spasm, we compared the action of acetylcholine with that of ergonovine in 11 patients with vasospastic angina (group 1) and in 15 patients with chest pain (group 2). Coronary arteriography was performed immediately after the patients received intracoronary injections of titrated increments of each agent. In the patients in group 1 occlusive or near-occlusive (99% luminal narrowing) coronary spasm associated with angina and ischemic electrocardiographic ST changes was noted in nine of 11 patients receiving acetylcholine and in all 11 patients receiving ergonovine. The region and the degree of the most severe coronary spasm on coronary arteriograms evoked by the two agents were the same in nine of the 11 patients in group 1. In the other two patients in group 1, spontaneous focal coronary spastic stenosis in the baseline coronary arteriogram was relieved by the intracoronary injection of acetylcholine, and a focal coronary occlusive spasm in the same region was induced repeatedly by the subsequent intracoronary injection of ergonovine (paradoxic phenomenon). In contrast, occlusive or near-occlusive coronary spasm was not induced by either agent in any patient in group 2. These results suggest that the two provocative tests for coronary spasm that involve acetylcholine and ergonovine are clinically useful in the diagnosis of vasospastic angina, but testing with intracoronary ergonovine is needed when a spontaneous focal coronary spasm is relieved by the intracoronary injection of acetylcholine. The results also indicate that in many patients with vasospastic angina, nonspecific hypersensitivity to acetylcholine or ergonovine in a definite region of the coronary arteries generally plays an important role in the induction of coronary spasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗