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Biomedical subjects

K Fukamachi

Publications and source records attributed to K Fukamachi.

At least 37 records · Page 2Linked to original sources
PubMed1993

Effects of preserving mitral apparatus on ventricular systolic function in mitral valve operations in dogs.

The mitral apparatus can affect left ventricular function through various mechanisms, such as the direct mechanical coupling between the mitral anulus and papillary muscle and the mitral annular contraction. To evaluate the relative contribution of these mechanisms, we investigated in five groups of 35 dogs that underwent open chest operations how preservation of the mitral apparatus affects left ventricular systolic function. We performed atriotomy in the first group. We sutured a prosthetic rigid ring around the mitral anulus in the second group. We replaced the mitral valve and preserved the anterior chordae in the third group, the posterior chordae in the fourth group, and no chordae in the fifth group. The postoperative percentage of recovery of ventricular function (as assessed by the slope of the end-systolic pressure-volume relation) from preoperative control values were 92.2% +/- 4.8%, 89.5% +/- 12.8%, 85.7% +/- 9.5%, 75.1% +/- 12.9%, and 61.3% +/- 8.0%, respectively. Preservation of the mitral apparatus significantly improved left ventricular function compared with that of conventional mitral valve replacement. The average relative contribution of the ventricular muscle to left ventricular function, the mitral anulus-papillary muscle continuity, and the mitral annular contraction were 66.5%, 30.6%, and 2.9%, respectively. We conclude that it is more beneficial to preserve the mitral apparatus in mitral valve replacement. The prosthetic ring does not detract from the functional benefit of the preservation of the mitral apparatus.

Animals↗
PubMed1993

[Concentration of PCDDs, PCDFs and coplanar PCBs in breast milk of Yusho patients and normal subjects].

Levels of PCDDs, PCDFs and coplanar PCBs were measured in human breast milk obtained from two Yusho patients and nine healthy subjects. The concentrations of PCDDs, PCDFs and coplanar PCBs in the breast milk of respective Yusho patients were 18.2 and 28.9, 168.8 and 418.3, and 23.8 and 55.1 pg Toxic Equivalents (TEQs)/g fat, respectively, and their mean concentrations in normal controls were 8.2, 5.1 and 21.8 pg TEQ/g fat, respectively. The results also indicated that there was a significant difference between Yusho patients and normal subjects in the concentrations of certain isomers of PCDDs, PCDFs and coplanar PCBs in the breast milk. For example, the levels of 1, 2, 3, 6, 7, 8-HxCDD were 4 and 8 times higher than the mean concentration in the normal subjects, and 2, 3, 4, 7, 8-PeCDF, 1, 2, 3, 4, 7, 8-HxCDF and 1, 2, 3, 6, 7, 8-HxCDF, so-called 'Yusho isomers' were 15 to 98 times higher than those in the normal subjects. Daily intakes of TEQ values were estimated to be 506 and 2200 pg TEQs/kg/day for breast-feeding babies of Yusho patients, and to be from 97 to 197 pg TEQs/kg/day for healthy subjects. These TEQ values were much greater than the ADI of 1-10 pg/kg/day, therefore, we should give due attention to the possible health effects due to PCDDs, PCDFs and coplanar PCBs in the breast milk of healthy mothers, as well as Yusho mothers.

Adult↗
PubMed1993

Chronic in vivo function of a new ventricular assist device: the extracorporeal pulsatile assist device (EPAD).

An extracorporeal pulsatile assist device (EPAD) is a valveless, single-chambered, pneumatically-actuated blood pump composed of a graft conduit, connecting ring, bladder, and blowmolded housing. This allows a simple and quick surgical procedure and is easily actuated with a conventional intraaortic balloon pumping console if desired. To evaluate in vivo pump functions, the EPAD was tested in calves as a left ventricular assist device for 6-24 days. The EPAD was well synchronized to the natural heart beat up to 130 bpm in the counterpulsation mode with mild systemic heparinization (active clotting time: 200-250 seconds). Heart rate, coronary flow and cardiac output were not significantly changed by on-off testing. However, the pump showed promising diastolic augmentation (10.8% increase in the diastolic pressure time index) in these chronic animal experiments.

Animals↗
PubMed1992

Effects of diltiazem and noradrenaline on extracellular potassium changes in the globally ischaemic rat heart.

OBJECTIVE: The aim was to investigate the effects of a calcium antagonist (diltiazem) and a catecholamine (noradrenaline) on extracellular potassium accumulation during global ischaemia. METHODS: Extracellular potassium concentration ([K+]e) was measured during 30 min global ischaemia in the isolated rat heart using a valinomycin potassium sensitive electrode. Contracture development during ischaemia was measured throughout with an intraventricular balloon inserted into the left ventricle and myocardial adenine nucleotides were measured in separate series of hearts. RESULTS: In control hearts, [K+]e showed a characteristic triphasic change during 30 min global ischaemia. This consisted of an early rising phase followed by a transient falling phase after the initial peak of [K+]e, and then a late rising phase. Diltiazem suppressed the rate of rise of [K+]e during early ischaemia, but extended the time course of the early [K+]e rise with the higher dose, abolishing the transient falling phase of [K+]e. During late ischaemia, the rise in [K+]e was attenuated by diltiazem. Noradrenaline also suppressed the early extracellular potassium accumulation, but in contrast to diltiazem, hastened the time course of the late [K+]e rise. CONCLUSIONS: Although diltiazem suppresses the early potassium loss during ischaemia as previously described, the drug also decreases the [K+]e fall by some as yet unknown mechanism, so that the [K+]e level becomes higher than control during the falling phase.

Adenosine Triphosphate↗
PubMed1991

Effects of glibenclamide and nicorandil on cardiac function during ischemia and reperfusion in isolated perfused rat hearts.

We examined influences of a blocker (glibenclamide) and an opener (nicorandil) of the ATP-sensitive potassium (KATP) channel on extracellular K concentration [( K+]e), as well as the myocardial function and metabolites during global ischemia and reperfusion in Langendorff-perfused rat heart preparation. In control hearts, [K+]e began to rise 20 s after the onset of ischemia up to an initial peak (8.3 +/- 0.3 mM) at 2.5 +/- 0.7 min, then fell to 6.0 +/- 0.8 mM after 8.2 +/- 0.7 min, and then rose progressively to 14.6 +/- 0.8 mM at the end of 30 min of ischemia. Glibenclamide (50 microM) reduced the initial peak of [K+]e to 7.2 +/- 0.3 mM (P less than 0.01), and nicorandil (200 microM) increased it to 9.4 +/- 0.6 mM (P less than 0.01). There were no significant differences in [K+]e values among all groups at the end of ischemia. During ischemia, nicorandil decreased the time to mechanical arrest from 1.9 +/- 0.1 min to 1.5 +/- 0.1 min, whereas it was increased by glibenclamide to 2.7 +/- 0.4 min. In control hearts, the time to onset of ischemic contracture was 14.7 +/- 1.8 min. Nicorandil delayed onset of contracture and glibenclamide accelerated it. Thus we have confirmed that some part of the early increase in [K+]e during ischemia is attributable to K+ efflux through the KATP channel in our model, and opening of the KATP channel may contribute to a rapid reduction of the contractility of the ischemic myocardium that subsequently protects the myocardium against further ischemic injury.

Adenosine Triphosphate↗
PubMed1991

[Concentration profile of PCBs in the digestive tract of rat fed with cholestyramine and rice bran fiber diet].

The aim of this study is to examine the inhibitory effect of rice bran fiber (RBF) and cholestyramine for intestinal absorption of polychlorinated biphenyls (PCBs). Sixteen rats were orally given at the dose of 100 mg of PCBs per kg of the animal, and were divided into four groups (A-D): Rats in each group were housed with the normal diet for the first 7 days, and subsequently, were given with the same diet as control for group A, with the diet containing 10% RBF for group B, with the diet containing 5% cholestyramine for group C and with the combined diet containing 10% RBF and 5% cholestyramine for group D for the next 10 days. All rats were sacrificed on the 17th day after PCBs administration, and PCBs in contents of the digestive tracts were determined: small and large intestine resected was divided into two parts each of the same length, and the contents were chemically analyzed to determine PCBs. PCBs concentration in rats of group A decreased in order of upper portions (1.0 microgram/g) and then lower (0.6 microgram/g) of small intestine, and upper (0.5 microgram/g) and then lower (0.4 microgram/g) of large intestine. Decreasing the PCBs concentration might be due to re-absorption in the intestine. In the case of groups B-D, PCBs concentration was in order of upper and then lower of small intestine, and large intestine. It was indicated that PCBs re-absorption in intestine is inhibited by the intake of RBF, cholestyramine, and RBF and cholestyramine.

Animals↗
PubMed1991

[Coplanar PCBs, PCDFs and PCDDs in the subcutaneous adipose tissue of Yusho patients and normal controls].

3,4,3',4'-tetrachlorobiphenyl (T4CB), 3,4,5,3',4'-pentachlorobiphenyl (P5CB) and 3,4,5,3',4',5'-hexachlorobiphenyl (H6CB) [Co-PCBs] in the subcutaneous adipose tissue of seven Yusho patients and eight normal controls were determined to assess the contribution in the risk caused by the Yusho causual agents (PCBs, PCDFs, PCDDs and Co-PCBs) by using high resolution gas chromatography/high resolution mass spectrometry in selected ion monitoring mode. 3,4,3',4'-T4CB, 3,4,5,3',4'-P5CB and 3,4,5,3',4',5'-H6CB were detected in the subcutaneous adipose tissue of the Yusho patients at the levels, of 6 to 29 ppt, of 32 to 130 ppt and of 160 to 1,140 ppt, respectively. The TCDD-Eq (Equivalents) value calculated by TCDD-TEfs (Toxic Equivalent factors) was from 8 to 30 ppt. On the other hand, 3,4,3',4'-T4CB, 3,4,5,3',4'-P5CB and 3,4,5,3',4',5'-H6CB were detected in the subcutaneous adipose tissue of normal controls at the levels, of 3 to 9 ppt, of 41 to 280 ppt and of 47 to 200 ppt, respectively. The TCDD-Eq value calculated by TCDD-TEfs was from 9 to 57 ppt. In the Yusho patients, the average TCDD-Eq value calculated by TCDD-TEfs of the residual Co-PCBs, PCDFs and PCDDs was 17, 491 and 24 ppt, respectively. Therefore, we concluded that the typical symptoms for the Yusho patients are caused mostly by PCDFs.

Adipose Tissue↗
PubMed1991

[Therapeutic trial for promotion of fecal excretion of PCDFs and PCBs by the administration of cholestyramine in Yusho patients].

Any effective therapy for elimination of causal agents remaining in Yusho patients was not found until now. To know the profile of fecal excretion of polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs), the amounts of PCDFs and PCBs in the stool of six Yusho patients with the typical symptoms were determined. The stool samples of Yusho patients were collected in 1989. PCDFs, i.e., 2,3,7,8-tetrachlorodibenzofuran (TCDF), 2,3,4,7,8-pentachlorodibenzofuran (PnCDF), 1,2,3,4,7,8- and 1,2,3,6,7,8-hexachlorodibenzofurans (HxCDFs), 1,2,3,4,6,7,8-heptachlorodibenzofuran (HpCDF) and octachlorodibenzofuran (OCDF) were detected in all of the samples. PCDFs found in the stool samples were mostly PnCDF and HxCDFs. Of PCDFs detected, PnCDF and HxCDFs contributed to 42 +/- 4.7% and 43 +/- 5.5% as mean +/- SE, respectively. The fecal excretion of PnCDF and HxCDFs in Yusho patients was 720 +/- 490 pg/day and 790 +/- 620 pg/day as mean +/- SE, respectively. On the other hand, the fecal excretion of PnCDF and HxCDFs in normal controls was 32 +/- 13 pg/day and 47 +/- 5.2 pg/day as mean +/- SE, respectively. The fecal excretion of PnCDF and HxCDFs in Yusho patients was about 23 times and 17 times each higher than that in normal controls. The fecal excretion of PCBs in Yusho patients and normal controls was 400 +/- 430 ng/day and 150 +/- 39 ng/day, respectively, as mean +/- SE. In order to promote the excretion of these toxic chemicals in the stool of Yusho patients, the patients were continuously administered with cholestyramine, an anion exchange resin, at a dose of 4 g, 3 times a day, for 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzofurans↗
PubMed1991

Beneficial effect of pericardial meshing on left ventricular pump performance in dogs.

To evaluate the effects of pericardial meshing (multiple incisions on the pericardium) on cardiac function, we examined left ventricular pump performance before and after pericardial meshing in six open chest dogs. We evaluated left ventricular systolic properties with the slope of end-systolic pressure-volume relation and diastolic properties with end-diastolic pressure-volume relation (chamber compliance). Overall left ventricular performance was assessed with end-diastolic pressure versus cardiac output relation. Left ventricular chamber compliance was increased (31.3%) with pericardial meshing compared with direct closure of the pericardium, and cardiac output was increased (26.7%) for any given left ventricular end-diastolic pressure. The slope of the end-systolic pressure-volume relation was not altered in pericardial meshing. These results suggest that pericardial meshing improves left ventricular pump performance as a result of increasing left ventricular chamber compliance. This technique may benefit cardiac pump performance that is depressed by the direct closure of the pericardium after cardiac operations.

Animals↗
PubMed1990

The mechanism of protective effect of diltiazem on reperfusion-induced arrhythmias in isolated rat heart.

This investigation was undertaken to define the mechanism by which diltiazem protects against life-threatening, reperfusion-induced arrhythmias. Using an isolated retrogressively perfused rat heart preparation with transient coronary artery occlusion, we compared the effects of diltiazem in its active form (d-cis) to its stereo-isomer (1-cis). Pre-ischemic administration of d-diltiazem (5 x 10(-8), 5 x 10(-7), 5 x 10(-6) M) caused a dose-dependent reduction in ventricular arrhythmias upon reperfusion following 10 min of regional ischemia. The incidence of reperfusion-induced ventricular fibrillation (RVF) was 50%, 0% (p less than 0.05) and 0% (p less than 0.05) with 5 x 10(-8), 5 x 10(-7), 5 x 10(-6) M diltiazem, respectively, compared with 60% in the control group. Preischemic administration of the 1-isomer caused different dose-dependent reduction in RVF. With 5 x 10(-6) M, the 1-isomer also reduced the incidence of RVF to 0% (p less than 0.05). However below this concentration it was ineffective (67%). D-diltiazem (5 x 10(-7) and 5 x 10(-6) M) increased coronary flow from 11.5 +/- 1.9 ml/min to 15.3 +/- 1.6 ml/min (p less than 0.05) and 15.2 +/- 1.0 ml/min (p less than 0.05) respectively, prior to ischemia. In contrast, the same dose of the 1-isomer did not alter coronary flow. The highest dose (5 x 10(-6) M) of d-diltiazem decreased heart rate by approximately 30% during the reperfusion phase, but all other concentrations had no significant effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1990

A new method of retrograde cardioplegic administration. Right ventricular protection by right atrial perfusion cooling.

Retrograde administration of cardioplegic solution via the right atrium with continuous cooling of the right ventricular cavity (right atrial perfusion cooling) was assessed for its protective effect in 12 dogs with occlusion of the right coronary artery subjected to global ischemia for 60 minutes. After an initial administration of 4 degrees C crystalloid cardioplegic solution by antegrade aortic perfusion, myocardial protection was established either by right atrial perfusion cooling (group I; n = 6) or by antegrade aortic perfusion alone (group II; n = 6). The right ventricular temperature was approximately 15 degrees C in group I and 20 degrees C in group II. After ischemia for 60 minutes, the adenosine triphosphate content of the right ventricular free wall was significantly higher in group I than in group II (24.4 +/- 1.45 versus 13.8 +/- 2.34 mumol/gm dry weight, p less than 0.05). The percent recovery of right ventricular contractility, which was evaluated by end-systolic pressure-volume relationships, was significantly better in group I at each reperfusion period (30 minutes: 130.0% +/- 9.6% versus 86.1% +/- 11.8%, p less than 0.05; 60 minutes: 159.6% +/- 12.9% versus 96.5% +/- 20.1%, p less than 0.05). Postischemic right ventricular stiffness (reciprocal value of compliance) increased in group II compared with group I, although the difference was not statistically significant. There were no major differences in percent recovery of the left ventricular end-systolic pressure-volume relationships between the two groups. The evidence suggests that the right atrial perfusion cooling method produces excellent right ventricular protection.

Animals↗
PubMed1990

Effects of left heart bypass on right ventricular performance. Evaluation of the right ventricular end-systolic and end-diastolic pressure-volume relation in the in situ normal canine heart.

Although left heart bypass has gained popularity as a powerful technique to assist the severely failed left heart, apparent right heart failure has often developed during the bypass procedure. We investigated whether the coexisting right heart failure is attributable to the left heart bypass in 16 open-chest dogs. We evaluated the effects of left heart bypass on the right ventricular systolic properties by the slope of the end-systolic pressure-volume relation and its effects on the diastolic properties by chamber compliance. Overall right ventricular performance was assessed by the end-diastolic pressure versus cardiac output relationship. The left heart bypass decreased the slope slightly when the assisted flow ratio exceeded 75% (-14% +/- 8% at the assisted flow ratio of 100%, p less than 0.02) and thus had a deleterious influence on right ventricular performance. The left heart bypass, on the other hand, had a counteracting beneficial influence on right ventricular performance through the increase in chamber compliance (38% +/- 5%, p less than 0.01) and the decrease in pulmonary arterial input resistance (-15% +/- 12%, p less than 0.01). The net effect of the left heart bypass was the increase in cardiac output (20% +/- 2%, p less than 0.05) for any given right ventricular end-diastolic pressure. We conclude that in normal hearts the left heart bypass augments right ventricular performance. We ascribe these beneficial effects to diastolic ventricular interdependence and afterload unloading.

Animals↗
PubMed1989

[Statistical analysis of subjects with type A, BC and C pattern of blood PCB on GC].

Various combinations of measured data on PCBs, PCQs, and PCDFs in adipose tissue or blood were tested on its discriminating power between normal persons and persons poisoned by yusho oil. The most discriminative single parameter was concentration of PCDF in adipose tissue. Furthermore, discriminative power increased by using additional parameters.

Adipose Tissue↗
PubMed1989

[Polychlorinated dibenzofurans (PCDFs) in the subcutaneous adipose tissue of yusho patients and normal controls].

Polychlorinated dibenzofurans (PCDFs) are well known to be the toxic chemicals in both animal experiments and human studies. It is, therefore, important to determine the level of PCDFs still retained in patients for understanding relationship between the concentration of PCDFs and present symptoms of the disease. In this study, the abdominal subcutaneous adipose tissue of 18 yusho patients and those of 11 normal controls who were all of volunteers were collected, and their levels were determined by high resolution gas chromatography/high resolution mass spectrometry. Results obtained were as follows: The principal compounds detected in the adipose tissue of yusho patients were 2,3,4,7,8-pentachlorodibenzofuran (PenCDF), 1,2,3,4,7,8- and 1,2,3,6,7,8-hexachlorodibenzofuran (HCDF). The concentration of the compounds in 7 patients, wearing typical symptoms, from 160 to 3,000 ppt for 2,3,4,7,8-PenCDF, from 51 to 1,000 ppt for 1,2,3,4,7,8-HCDF, and from 16 to 220 ppt for 1,2,3,6,7,8-HCDF. In normal controls, 2,3,4,7,8-PenCDF was detected only in five samples at the low level of from 16 to 38 ppt. On an average, PCDF levels in in the typical 7 yusho patients and 11 normal controls were 1,900 ppt and 16 ppt, respectively. On the basis of the results, the concentrations of PCDF congeners in the adipose tissues of the typical 7 patients was 100 times higher than that of the normal controls. Hence, we consider that the present levels of PCDFs in the patients probably play an important role for the symptoms of the yusho.

Adipose Tissue↗
PubMed1989

[Polychlorinated dibenzo-p-dioxins in the subcutaneous adipose tissue of yusho patients].

The abdominal subcutaneous adipose tissues, the mother milk, and the blood samples of yusho patients were collected between 1986 and 1988, and analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) by high resolution gas chromatography/high resolution mass spectrometry in selected ion monitoring mode. PCDDs and PCDFs were found all of the samples examined.: 1,2,3,7,8-Pentachlorodibenzo-p-dioxin (pentaCDD), 1,2,3,6,7,8-hexaCDD, octaCDD, 2,3,4,7,8-pentachlorodibenzofuran (pentaCDF), and 1,2,3,4,7,8- and 1,2,3,6,7,8-hexaCDF were detected. The levels of PCDDs was several times lower than those of PCDFs in all samples. The concentrations of PCDDs and PCDFs found in the fat of the mother milk were similar to those of the adipose tissues. On the other hand, the levels of PCDDs and PCDFs in the blood samples were several hundred times less than those of the adipose tissues.

Adipose Tissue↗
PubMed1989

[Clinical assessment of anticoagulation therapy during left ventricular assist with artificial heart: induction with protease inhibitor].

Left ventricular assist device was attached to five patients suffered from severe low cardiac output after open heart surgery. In two patients, anticoagulation therapy with heparin started just after the operation. Repeated operations for hemostasis were required because of massive bleeding in these two patients. Anticoagulation therapy was not performed in another one, and thrombus formation in the device was recognized in this patient. In the other two patients, anticoagulation therapy was started with large dose of protease inhibitor (gabexate mesilate or nafamstat mesilate). Heparin infusion was combined with protease inhibitor during the period of weaning from the device. Thrombosis and massive bleeding were not recognized in these two patients, and they were able to wean from the device successfully.

Aged↗
PubMed1989

[Myocardial protection during transplantation procedure following cold storage in Collins' solution].

The purpose of this study is to evaluate the myocardial protective effects of two types of solution during heart transplantation procedure following cold storage in Collins' solution. Based on the concept whether the ischemic time during the procedure is an extension of heart storage or is an usual aortic cross-clamped ischemic time, we compared the effects of our cardioplegic solution (Group I) and Collins' solution (Group II) using isolated working rat heart model. After 30 minutes of global ischemia at 25 degrees C following 2 hours of cold storage, the hearts in Group I exhibited better functional recovery than those in Group II (% recovery of cardiac output was 61.1 +/- 5.4% in Group I and 42.4 +/- 7.4% in Group II, p less than 0.01). In Group II, marked elevation of coronary vascular resistance occurred on reperfusion. CPK release during reperfusion period was greater in Group II (0.41 +/- 0.24 IU/15 min/heart in Group I, 1.92 +/- 1.25 IU/15 min/heart in Group II, p less than 0.01). Myocardial metabolites contents (ATP, TAN, creatine phosphate and lactate) and energy charge were not significantly different between two groups. We conclude that it is harmful to ischemic myocardium to use Collins' solution as myocardial protection during transplantation procedure even if following cold storage in Collins' solution.

Animals↗