Biomedical subjects

N Hayashida

Publications and source records attributed to N Hayashida.

At least 37 records · Page 2Linked to original sources

PubMed2000

Effects of angiotensin-converting enzyme inhibitor during warm blood cardioplegia.

BACKGROUND: Effects of captopril, an angiotensin-converting enzyme inhibitor, during warm blood cardioplegia were assessed in the blood-perfused, isolated rat heart. METHODS: The isolated hearts were arrested for 60 minutes with warm blood cardioplegia given at 20-minute intervals and were reperfused for 60 minutes. The control group (n = 10) received standard cardioplegia and the captopril group (n = 10) received cardioplegia supplemented with captopril (2 mmol/L). Cardiac function, myocardial metabolism, and cardiac release of circulating adhesion molecules were assessed before and after cardioplegic arrest. RESULTS: Left ventricular end-diastolic pressure and -dp/dt were significantly (p<0.05) lower and coronary blood flow was significantly (p<0.05) greater in the captopril group than the control group during reperfusion. The captopril group resulted in significantly (p<0.05) less cardiac release of lactate, thiobarbituric acid reactive substances during reperfusion. Cardiac release of intercellular adhesion molecule-1 was significantly (p<0.05) less in the captopril group at 60 minutes of reperfusion. CONCLUSIONS: The results suggest that supplementation of captopril during warm blood cardioplegia provides superior myocardial protection by suppressing lipid peroxidation and leukocyte-endothelial cell interaction during reperfusion.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2000

Effects of intraoperative administration of atrial natriuretic peptide.

BACKGROUND: Biological activity of endogenous atrial natriuretic peptide (ANP) may decrease during cardiopulmonary bypass. To evaluate the effects of intraoperative administration of exogenous ANP in patients undergoing cardiopulmonary bypass, we conducted a prospective randomized study. METHODS: Eighteen patients undergoing mitral valve surgery were randomized to receive either ANP treatment (ANP group; n = 9) or no ANP treatment (control group; n = 9). Atrial natriuretic peptide was given immediately after initiation of cardiopulmonary bypass for 6 hours (0.05 microg x kg(-1) x min(-1)). Plasma ANP, brain natriuretic peptide and cyclic guanosine monophosphate (cGMP) levels, hemodynamic variables and renal function were assessed perioperatively. RESULTS: Administration of ANP increased plasma cyclic guanosine monophosphate levels, urine output and fractional sodium excretion, and decreased preload, afterload and plasma brain natriuretic peptide levels significantly (p < 0.05). Plasma cyclic guanosine monophosphate levels correlated with plasma ANP levels (r = 0.95, p = 0.0001), correlated with fractional sodium excretion (r = 0.53, p = 0.02), and correlated inversely with systemic vascular resistance (r = -0.54, p = 0.02). CONCLUSIONS: Intraoperative administration of ANP had potent effects on natriuresis and systemic vasodilation by elevating cyclic guanosine monophosphate levels. The results suggest that the technique is useful for the management of hemodynamics and water-sodium retention after cardiopulmonary bypass.

Adult↗

PubMed2000

Internal thoracic artery as a collateral source to the ischemic lower extremity.

Based on the superior long-term results, internal thoracic artery is widely used for coronary artery bypass grafting. However, the vessel can play an important role as a collateral source to the chronically ischemic lower limbs. We reported two cases who underwent simultaneous revascularization to the myocardium and lower limbs because this particular condition was anticipated. Selective angiography of internal thoracic artery was useful to determine its role before harvesting in our cases. Careful preoperative examinations and choice of surgical approach are required for such patients to avoid serious vascular complications.

Angiography, Digital Subtraction↗

PubMed2000

Biological activity of endogenous atrial natriuretic peptide during cardiopulmonary bypass.

To evaluate the effect of cardiopulmonary bypass (CPB) on atrial natriuretic peptide (ANP) biological activity in patients undergoing cardiac operations, we conducted a prospective study. Ten patients undergoing mitral valve surgery were enrolled. Plasma levels of ANP and cyclic guanosine monophosphate (cGMP), hemodynamic variables, and renal function parameters were assessed perioperatively. The molar ratio of cGMP to ANP (as a marker for ANP biological activity) decreased significantly (p < 0.05) during CPB despite similar plasma ANP levels. The ratio correlated inversely with the duration of CPB (r = -0.85, p = 0.002). The ratio also correlated with fractional sodium excretion (r = 0.65, p = 0.04) and correlated inversely with pulmonary vascular resistance (r = -0.79, p = 0.009) and atrial filling pressure (r = -0.84, p= 0.003) postoperatively. CPB decreased the molar ratio of cGMP to ANP, which may represent ANP biological activity, such as vasodilation and natriuresis. The phenomenon may contribute to water-sodium retention and pulmonary hypertension after cardiac surgery.

Analysis of Variance↗

PubMed2000

Biocompatibility of heparin-coated extracorporeal bypass circuits: new heparin bonded bioline system.

Biocompatibility of a new type of heparin-coated cardiopulmonary bypass equipment, the Bioline, was evaluated in coronary artery bypass surgery cases. The heparin-coated (H) group (n = 15; Quadrox Bioline oxygenator/reservior and Carmeda BioMedicus BP-80 centrifugal pump) was compared with the nonheparin-coated (N) group (n = 12; uncoated, otherwise similar oxygenator, centrifugal pump, tubing, and filter set). Both groups used full systemic heparinization. The peak values of neutrophil elastase, C3a, IL-6, and IL-8 at 2 h after cardiopulmonary bypass (CPB), and C3a levels at the end of CPB and at 2 h after CPB were significantly reduced in the H group compared with those of the N group. However, no statistically significant intergroup differences were observed in thrombin-antithrombin complex, D-dimer, beta-thromboglobulin, or platelet factor-4. No significant differences were observed in hemostasis time, postoperative 12 h blood loss, required amount of blood transfusion, or intubation time. In conclusion, the Bioline demonstrated partially improved biocompatibility, in terms of leukocyte and complement activation, and proinflammatory cytokine production. However, it did not improve platelet activation, coagulation, or fibrinolysis cascade under full systemic heparinization. As a result, the clinical beneficial impact seemed to be the minimum.

Aged↗

PubMed2000

Obstruction of St Jude Medical valves in the aortic position: significance of a combination of cineradiography and echocardiography.

BACKGROUND: Obstruction of the St Jude Medical valve (St Jude Medical, Inc, St Paul, Minn) is a rare but serious complication. METHODS: Cineradiographic and echocardiographic evaluations of aortic St Jude Medical valves were simultaneously performed on 54 patients, with no signs of prosthetic valve dysfunction late after surgery. RESULTS: Although closing angles of the leaflets corresponded closely with the manufacturer data, restricted opening of the leaflets (opening angle >/= 20 degrees ) was found in 16 (group D) of the 54 patients by means of cineradiography. The opening angles were equal to or less than 14 degrees in the other 23 patients (group N) and between 15 degrees and 19 degrees in the remaining 15 (group M). Doppler-derived transprosthetic pressure gradients were significantly higher (P =.03) and the velocity index was significantly lower (P =.003) in group D than in group N. However, no significant differences were found in those values between group N and group M. Replacement of the aortic St Jude Medical valves was performed in 5 of the 16 patients, and the remaining 11 have been followed up because of relatively low pressure gradients. The cause of restricted leaflet movement was pannus formation without thrombosis in 4 patients and valve thrombosis with pannus formation in one. CONCLUSIONS: Reduced valve orifice area and restricted opening of the leaflets resulting from excess growth of pannus probably led to obstruction of the aortic St Jude Medical valves. A combination of cineradiography and echocardiography makes it possible to provide an accurate and detailed diagnosis of obstruction of the valve.

Adolescent↗

PubMed2000

Plasma and urinary levels of heart fatty acid-binding protein in patients undergoing cardiac surgery.

To evaluate the clinical significance of the plasma and urinary levels of heart fatty acid-binding protein (H-FABP) in patients undergoing cardiac surgery, a prospective study was conducted. Ten patients undergoing coronary artery bypass grafting were enrolled. Blood samples for determination of plasma H-FABP (pH-FABP), the MB isoenzyme of creatine kinase (CK-MB) and troponin-T (TnT), and urine samples for determination of urinary H-FABP (uH-FABP) were collected serially. None of the patients had perioperative myocardial infarction. The time to reach the peak level after aortic declamping was significantly (p<0.05) shorter for pH-FABP (1.4+/-0.5 h) than for CK-MB (2.5+/-0.5 h), TnT (6.6+/-1.3 h) or uH-FABP (3.0+/-0.6 h). Peak levels of pH-FABP correlated with those of CK-MB (r = 0.51, p = 0.04), TnT (r = 0.60, p = 0.03) and uH-FABP (r = 0.61, p = 0.03), and peak levels of uH-FABP correlated with CK-MB (r = 0.57, p = 0.04). Postoperative uH-FABP levels correlated inversely with the left ventricular stroke work index (r = -0.63, p = 0.04). This study demonstrated that H-FABP appears rapidly in plasma after reperfusion and reaches its peak earlier than other available biochemical markers; it appears also in urine and the levels correlated with cardiac function. Plasma and urinary H-FABP may be an early and sensitive biochemical marker for the diagnosis of myocardial injury in patients undergoing cardiac surgery.

Blood Pressure↗

PubMed2000

Plasma exchange for hyperbilirubinemia following implantation of a left ventricle assist system: a case report.

A 49-year-old patient with end-stage dilated cardiomyopathy underwent implantation of a left ventricular assist system (LVAS). Although the systemic circulation seemed to be improved, the serum total bilirubin (Tbili) level increased sharply in the early postoperative period (preoperative Tbili, 5.7 mg/dl; postoperative day 3, 33.6 mg/dl). Plasma exchange (PE) was performed 7 times from postoperative day 4, and the Tbili level decreased to 16.3 mg/dl by postoperative day 11. Thereafter, serum Tbili normalized concomitant with improved circulatory condition. The cause of the hyperbilirubinemia was considered to be temporary right ventricular dysfunction or hepatic sinusoid endothelial dysfunction. The liver function was recoverable, so PE had been effective in this case. Unfortunately, the patient suffered a midbrain infarction and ultimately died. From this experience, PE is recommended if it is judged that liver function can be preserved and circulation is adequate, but its implementation should not be delayed. It is essential that LVAS is implanted before damage occurs to end-organ function and thus prevent hyperbilirubinemia.

Cardiomyopathy, Dilated↗

PubMed2000

Coronary artery bypass surgery in a patient with myasthenia gravis.

A 73-year-old man with myasthenia gravis required quadruple coronary artery bypass grafting due to triple-vessel disease. Anesthetic management was performed with general anesthesia using a reduced dose of muscle relaxant with the aid of a neuromuscular transmission monitor. He was extubated 14 hrs after surgery without difficulty under this monitor. His postoperative course was uneventful. A patient with myasthenia gravis who required coronary artery bypass surgery was successfully performed by the deliberate preoperative evaluation of patient's myasthenic and cardiac status, and by the careful perioperative management.

Aged↗

PubMed2000

Effects of supplemental L-arginine during warm blood cardioplegia.

OBJECTIVES: Effects of supplemental L-arginine, nitric oxide precursor, during warm blood cardioplegia were assessed in the blood perfused isolated rat heart. METHODS: The isolated hearts were perfused with blood at 37 degrees C from a support rat. After 20 minutes of aerobic perfusion, the hearts were arrested for 60 minutes with warm blood cardioplegia given at 20-minute intervals. This was followed by 60 minutes of reperfusion. The hearts were divided into the following three groups according to the supplemental drugs added to the cardioplegic solution. The control group (n = 10) received standard warm blood cardioplegia. The L-ARG group (n = 10) received warm blood cardioplegia supplemented with L-arginine (3 mmol/l). The L-NAME group (n = 10) received warm blood cardioplegia supplemented with L-arginine (3 mmol/l) and L-nitro-arginine methyl ester, a competitive inhibitor of nitric oxide synthase (1 mmol/l). After 60 minutes of cardioplegic arrest, cardiac function, myocardial metabolism and myocardial release of circulating adhesion molecules were measured during reperfusion. RESULTS: Left ventricular end-diastolic pressure was significantly lower (p<0.05) in the L-ARG group than in the control group and the L-NAME group during reperfusion. Isovolumic left ventricular developed pressure, dp/dt and coronary blood flow were significantly greater (p< 0.05) in the L-ARG group during reperfusion. The L-ARG group resulted in early recovery of lactate metabolism during reperfusion. Myocardial release of circulating intercellular adhesion molecule-1 (ICAM-1) and E-selectin were significantly less (p<0.05) in the L-ARG group at 15 minutes of reperfusion. CONCLUSIONS: The results suggest that augmented nitric oxide by adding L-arginine to warm blood cardioplegia can preserve left ventricular function and ameliorate endothelial inflammation. The technique can be a novel cardioprotective strategy in patients undergoing cardiac surgery.

Animals↗

PubMed2000

[A case study of alpha feto protein (AFP)-producing gastric carcinoma with multiple liver metastases, in which chemotherapy was effective enough to once save a life in rapid decline].

A 57 year-old man visited our hospital with general fatigue and a sensation of abdominal fullness. He had lost 10 kg in body weight during the previous 3 months. Between admission and the time the diagnosis of AFP-producing gastric carcinoma with multiple liver metastases was made, his condition deteriorated quickly due to the rapid growth of the liver metastases. Combined chemotherapy consisting of cisplatin and 5-FU was given, and was so effective that the patient recovered well and both serum AFP level and the size of the swollen liver decreased markedly. However, about a month after being discharged, he experienced a relapse and was readmitted. After obtaining informed consent, chemotherapy consisting of methotrexate and 5-FU was started. Though the level of tumor markers and LDH decreased significantly, he died of hepatic failure. We think that this case is worthy of notice because it shows the effectiveness and limitations of chemotherapy in a situation where the condition of a patient is deteriorating quickly due to rapid extension of an AFP-producing gastric carcinoma.

Adenocarcinoma↗

PubMed2000

A case report of surgical treatment of quadricuspid aortic valve associated with regurgitation.

A case of a 65-year-old woman who had a quadricuspid aortic valve associated with aortic regurgitation is reported. The patient had severe aortic regurgitation and four equally divided aortic cusps. The valve abnormality was detected by a transesophageal echo and an aortography. The incomplete aortic valve was excised and replaced by a St. Jude Medical prosthesis. Although this case had no coronary abnormality, a coronary displacement is often reported in quadricuspid aortic valve cases. In order to perform an operation safely, accurate information which is obtained by a non-invasive examination of the transesoph-ageal echo is quite valuable as it can indicate the need for further preoperative examinations of the coronary arteries.

Aged↗

PubMed2000

ATS prosthetic valve motion: an in vitro analysis.

BACKGROUND AND AIM OF THE STUDY: We have reported clinical findings that normally functioning open pivot ATS valves did not open completely. In order to analyze features of the ATS valve motion more precisely, in vitro tests were conducted. METHODS: Opening angles and pressure gradients of the ATS valve were measured and compared with those of the St. Jude Medical (SJM) valve under steady flow, but with various outlet configurations. Second, opening angles of the two valves were measured under pulsatile conditions in two different outflow configurations: (i) a 'straight outlet' where the leaflets did not extend into the tapering outflow chamber, and (ii) an 'abrupt enlargement outlet' where the leaflets extended directly into the enlarged outflow space. Third, flow visualization studies were made under steady flow conditions in the straight and abrupt enlargement outlet conduits, respectively. RESULTS: Under steady flow conditions, opening of the ATS valve was restricted in most outflow configurations; only when the outlet angle was 0 degrees did the valve open fully. The SJM valve opened completely in all downstream configurations. Despite restricted opening in the ATS valve, the pressure gradient was similar in both valves. Under pulsatile conditions, both valves opened fully in the straight outlet; however, in the abrupt enlargement outlet the ATS valve opened incompletely and the SJM valve completely. Substantial turbulent flow was observed at the outside of the leaflet and corners of the conduit, notably with the ATS valve. CONCLUSION: This study showed that the ATS valve did not open fully except when the outflow was straight, and the leaflet did not extend into an enlarged downstream chamber. Structural features of the ATS, such as its axis being located close to the straight edge and its leaflets extending further downstream from the ring orifice, may cause this unique valve behavior.

Heart Valve Prosthesis↗

PubMed1999

Hypofibrinogenemia associated with a heterozygous missense mutation gamma153Cys to arg (Matsumoto IV): in vitro expression demonstrates defective secretion of the variant fibrinogen.

We genetically analyzed a case of hypofibrinogenemia that showed no bleeding or thrombotic tendency. Direct sequencing of a polymerase chain reaction-amplified gamma-chain gene segment showed a novel nucleotide substitution. This heterozygous mutation encodes both Cys (TGT) and Arg (CGT) at residue 153. To examine the basis for the fibrinogen deficiency, we prepared expression vectors containing mutant gamma-chain DNAs encoding gamma153R and gamma153A for in vitro expression in Chinese hamster ovary (CHO) cells. Enzyme-linked immunosorbent assay and immunoblot analysis of the culture media and cell lysates showed that CHO cells transfected with gamma153R or gamma153A synthesized the variant gamma-chain, but did not secrete variant fibrinogen into the culture medium. Metabolic pulse-chase experiments showed that fibrinogen assembly was impaired when either variant gamma-chain was expressed. In cells expressing normal fibrinogen, assem- bly intermediates and intact fibrinogen were seen in cell lysates prepared after short (3 minutes) or long (1 hour) incubation with (35)S-methionine. Neither intermediates nor intact fibrinogen was seen with the variant gamma-chains. These data suggest that gamma-chains have an important early role in fibrinogen assembly. Thus, our results support the model for fibrinogen assembly proposed by Huang et al (J Biol Chem 268:8919, 1993), in which the first step in assembly is the formation of alphagamma or betagamma dimers, or both. This model implies that gammaCys153 has a critical role in the formation of these early assembly intermediates. We concluded that the gamma153Cys-->Arg substitution does not allow fibrinogen assembly and secretion, and this is manifest in vivo as a fibrinogen deficiency. We designated this variant as fibrinogen Matsumoto IV.

Adult↗

PubMed1999

A successful case of pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension with a thrombus in the right ventricle.

Chronic thromboembolism is a frequent cause of progressive hypertension and carries a poor prognosis. Medical treatment is not effective and surgery provides the only potential for a cure at present. We herein report a successful case of thromboendarterectomy treated via a median sternotomy with intermittent circulatory arrest. A 43-year-old man was admitted to our hospital complaining of progressive dyspnea, edema of the lower extremities, and a fever with an unknown origin. A subsequent definitive evaluation showed him to be suffering from surgically accessible chronic thromboembolic pulmonary hypertension with a thrombus in the right ventricle. He underwent a pulmonary thromboendarterectomy and thrombectomy via a median sternotomy with intermittent circulatory arrest on November 24, 1994. Postoperatively he showed a marked improvement in his hemodynamic status and blood gas analysis. He has also returned to work with no trouble. Deep vein thrombosis appeared to be the pathogenesis of this case, but we could not find the origin of his unknown fever. He is currently being controlled by treatment with methylprednisolone as before.

Adult↗

PubMed1999

Morphology and histology of human and canine internal thoracic arteries.

BACKGROUND: We evaluated human and canine internal thoracic arteries (ITAs) to determine whether the latter is valid for studies relevant to clinical use. METHODS: We studied 19 human ITAs obtained from 1 female and 14 male victims of recent fatal accidents who had no evidence of cardiovascular disease (mean age = 39+/-19 years; range = 15 to 79 years), and ITAs of 21 randomly-selected mongrel dogs of both sexes, weighing 18-40 kg (average = 24.3+/-5.7 kg). Specimens were fixed in formalin at a controlled pressure of 120 mm Hg, before extensive assessment that included intimal thickening, condition of the internal elastic lamina, and number of medial elastic lamellae and vasa vasorum. RESULTS: The canine morphology and histology were similar to the human ITAs, but there was no intimal hyperplasia, and the media and adventitia were thinner (ITAs of humans older than 40 years had significant increases in medial thickness, as well as in overall length). Morphologically and histologically, the left and right canine ITAs were almost completely the same. CONCLUSIONS: Canine ITAs are valid for bilateral comparative studies and are a useful tissue source and model for clinically-relevant experimental studies.

Adolescent↗

PubMed1999

Inhibitory effect of milrinone on cytokine production after cardiopulmonary bypass.

BACKGROUND: It has been suggested that cyclic adenosine monophosphate-elevating agents suppress cytokine production. To evaluate the effects of milrinone, a phosphodiesterase III inhibitor, on cytokine production after cardiopulmonary bypass, we conducted a prospective randomized study. METHODS: Twenty-four patients undergoing coronary artery bypass grafting were randomized to receive either milrinone treatment (milrinone, n = 12) or no milrinone treatment (control, n = 12). Administration of milrinone (0.5 microg x kg(-1) x min(-1)) was started after induction of anesthesia and was continued for 24 hours. Blood samples for determination of plasma cyclic adenosine monophosphate, tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and interleukin-8 levels were collected perioperatively. RESULTS: No significant differences were observed in tumor necrosis factor-alpha and interleukin-8 levels between the groups. Interleukin-1beta and interleukin-6 levels after cardiopulmonary bypass were significantly (p < 0.05) lower in the milrinone group than in the control group. Plasma levels of cyclic adenosine monophosphate increased significantly (p < 0.05) after the administration of milrinone and the levels correlated inversely (r = -0.55, p < 0.01) with interleukin-6 levels. CONCLUSIONS: The results indicate that milrinone suppresses cytokine production by elevating cyclic adenosine monophosphate levels in patients undergoing cardiopulmonary bypass. With its positive inotropic and vasodilator activities, milrinone may have antiinflammatory effects.

Aged↗

PubMed1999

Regional insertional mutagenesis of genes on Arabidopsis thaliana chromosome V using the Ac/Ds transposon in combination with a cDNA scanning method.

For regional insertional mutagenesis of Arabidopsis thaliana genes, we combined a cDNA scanning method (Hayashida et al. Gene 1995; 165:155-161) and an Ac/Ds transposon designed for local mutagenesis, and evaluated this approach with two overlapping yeast artificial chromosome (YAC) clones, CIC7E11 and CIC8B11, on A. thaliana chromosome 5. We applied a previously developed novel cDNA selection method using DNA latex particles (cDNA scanning method) to the two YAC clones and constructed two sub-libraries in which cDNAs for genes on each YAC DNA were concentrated. From each sub-library we isolated cDNAs for genes on each YAC DNA, partially sequenced them, and produced expressed sequence tags (ESTs). In total, 113 non-redundant groups of cDNAs were obtained. Forty-four per cent of these EST clones were novel, and 34% had significant homology to functional proteins from various organisms. In parallel, we transposed Ds from a donor Ds-GUS-T-DNA line, Ds4391-20, already mapped to the CIC7E11/8B11 region. We obtained Ds-transposed lines and recovered their Ds-flanking genomic DNAs by thermal asymmetric interlaced (TAIL) polymerase chain reaction (PCR). Dot-blot analysis indicated that 20% of the lines contained transposed Ds in the CIC7E11/8B11 region, suggesting that this Ac/Ds transposon system is effective for regional insertional mutagenesis. To isolate Ds insertion mutants in the genes identified from the CIC7E11/8B11 region, we carried out PCR screening from 800 Ds-containing lines using Ds-specific and gene-specific primers that were designed from the 113 cDNA sequences identified by the cDNA scanning method. We found that 49 lines contain Ds insertion mutations, and that five lines contain Ds mutations in genes that are mapped to the sequenced CIC7E11/8B11 genomic DNA region. These results indicate that combining the cDNA scanning method and the Ac/Ds transposon gives a powerful tool for regional insertional mutagenesis not only in Arabidopsis but also in other plants or crops whose genomes are not sequenced.

Arabidopsis↗