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Biomedical subjects

K Minami

Publications and source records attributed to K Minami.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Anesthesia for patients with unexpected pulmonary embolisms due to a large abdominal tumor obstructing with inferior vena cava].

Several reports have highlighted the risk of pulmonary embolisms during the preoperative period in patients with large abdominal tumors obstructing the inferior vena cava. We describe a patient who developed pulmonary embolism just before surgery. A 68[correction of 64]-year-old female was scheduled to undergo elective resection of a large abdominal tumor under general anesthesia. She had no signs of deep venous thrombosis, but on the day of the operation, pulmonary embolism developed suddenly. Anticoagulant therapy was performed. Capnography and pulmonary artery pressure were monitored during the perioperative period to detect the recurrence of pulmonary embolism. The percutaneous cardio-pulmonary support (PCPS) was also prepared. The operation was performed successfully. In this patient, the pulmonary embolism occurred suddenly during the preoperative period, even though we had ruled out the existence of deep venous thrombosis. This case report emphasizes the risk of pulmonary embolism in any patient with a large abdominal tumor obstructing the inferior vena cava. This case of a large abdominal tumor suggests that capnography, monitoring of pulmonary artery pressure and preparation of a PCPS in case of pulmonary embolism during surgery are necessary even in patients without signs of deep venous thrombosis.

Abdominal Neoplasms↗
PubMed2001

[Anesthesia using propofol for a patient with arthrogryposis multiplex congenita].

Arthrogryposis multiplex congenita (AMC) is a syndrome with multiple persistent limb contractures, often accompanied by associated anomalies. Pediatric patients with AMC frequently require operations, necessitating general endotracheal anesthesia. We report on the anesthesia used for a 14-year-old male with AMC, who required the surgical removal of soft tissue from both hip joints. We used propofol and vecuronium bromide to induce anesthesia, and maintained anesthesia with 40% nitrous oxide, oxygen, and propofol at 6 mg.kg-1.1 hr-1. Both induction and maintenance were smooth, and no hyperthermia occurred perioperatively. Propofol can be safely used for anesthesia in AMC patients.

Adolescent↗
PubMed2001

[Difficult ventilation during induction of anesthesia in a patient with Arnold-Chiari malformation type II].

Arnold-Chiari malformation is a congenital disorder with caudal displacement of the cerebellar tonsils through the foramen magnum into the cervical canal. We report difficulty with ventilation during the induction of anesthesia due to apnea and laryngospasm in a 5-year-old female with Arnold-Chiari malformation type II diagnosed at birth. She had had short periods of apnea during infancy, but was asymptomatic recently. Slow induction of anesthesia was performed using sevoflurane, but just after induction, the patient developed apnea and we could not ventilate her due to laryngospasm. We woke her up, and induced anesthesia with barbiturates. The operation was performed without complications, but she had another apnea attack with laryngospasm at extubation. This case suggests that it is important to be aware of the possibility of apnea due to disorder of the respiratory center in patients with Arnold-Chiari deformity.

Anesthesia, Inhalation↗
PubMed2001

Inhibition by tramadol of muscarinic receptor-induced responses in cultured adrenal medullary cells and in Xenopus laevis oocytes expressing cloned M1 receptors.

Tramadol is a widely used, centrally acting analgesic, but its mechanisms of action are not completely understood. Muscarinic receptors are known to be involved in neuronal function in the brain and autonomic nervous system, and much attention has been paid to these receptors as targets of analgesic drugs in the central nervous system. This study investigated the effects of tramadol on muscarinic receptors by using two different systems, i.e., a Xenopus laevis oocyte expression system and cultured bovine adrenal medullary cells. Tramadol (10 nM-100 microM) inhibited acetylcholine-induced currents in oocytes expressing the M1 receptor. Although GF109203X, a protein kinase C inhibitor, increased the basal current, it had little effect on the inhibition of acetylcholine-induced currents by tramadol. On the other hand, tramadol did not inhibit the current induced by AlF4-, a direct activator of GTP-binding protein. In cultured bovine adrenal medullary cells, tramadol (100 nM-100 microM) suppressed muscarine-induced cyclic GMP accumulation. Moreover, tramadol inhibited the specific binding of [3H]quinuclidinyl benzilate (QNB). Scatchard analysis showed that tramadol increases the apparent dissociation constant (Kd) value without changing the maximal binding (Bmax), indicating competitive inhibition. These findings suggest that tramadol at clinically relevant concentrations inhibits muscarinic receptor function via QNB-binding sites. This may explain the neuronal function and anticholinergic effect of tramadol.

Acetylcholine↗
PubMed2001

Low dose systemic heparinization combined with heparin-coated extracorporeal circulation. Effects related to platelets.

BACKGROUND: A heparin coated cardiopulmonary bypass system combined with full and low dose systemic heparinization in coronary bypass surgery was investigated in a prospective, randomised study. Roller pumps, coronary suction and an open cardiotomy reservoir were used. METHODS: One hundred and nineteen patients were divided into 3 groups: group A (n=39) had a standard uncoated extracorporeal circulation (ECC)-set and systemic heparin was given in an initial dose of 400 IE/kg body weight. During ECC activated clotting time (ACT) was kept at = or >480 sec. Group B (n=42) had the same ECC-set completely coated with low molecular weight heparin, i.v. heparin was administered in the same dose as in group A, ACT was again kept at = or >480 sec. Group C (n=38) had the same coated ECC set as group B, but i.v. heparin was reduced to 150 IE/kg and during ECC ACT was maintained of = or >240 sec. RESULTS: Platelet decrease was significantly less in both groups utilizing coated circuitry as compared to control group A. Activation of thrombocytes as marked by b-thromboglobulin (not PF4) was significantly decreased in patients treated with coated circuits combined with low dose systemic heparinization and postoperative bleeding was significantly reduced. CONCLUSIONS: We conclude that in heparin coated extracorporeal circulation combined with either full dose or reduced systemic heparinization compared to uncoated circuits platelet count reduction is significantly less. Platelet activation as marked by b-thromboglobulin and postoperative blood loss are decreased with coated equipment and low i.v. heparinization.

Adult↗
PubMed2001

[INR self-management after mechanical heart valve replacement: ESCAT (Early Self-Controlled Anticoagulation Trial)].

Severe thromboembolic and hemorrhagic complications following mechanical heart valve replacement essentially occur due to intense oral anticoagulation and fluctuating individual INR values around the target range. INR self-management can help to minimize these fluctuations. Beginning this therapeutic control immediately after mechanical heart valve replacement further reduces anticoagulant-induced complications. Included in the study were 1200 patients. The quality of oral anticoagulation also improved through INR self-management. Over an observation period of two years, nearly 80% of INR values recorded by the patients themselves were within the target therapeutic range of 2.5-4.5. This corresponds to a high significance of p < = 0.001 in favor of INR self-management. Only 64.9% of INR values monitored by family practitioners were within the desired range. The results differed slightly in quality between patient groups with different levels of training (comprehensive, secondary modern, grammar with or without university). Of patients trained in INR self-management following mechanical heart valve replacement, 91.7% maintained their competence in this technique throughout the entire follow-up period. Only 8.3% of those trained immediately after surgery were unable to continue with INR self-management.

Administration, Oral↗
PubMed2000

Electrocardiographic remodeling in patients paced for heart failure.

Congestive heart failure due to advanced coronary artery disease or dilated cardiomyopathy is often associated with intraventricular conduction delays. Electrical resynchronization is an evolving method to improve clinical and functional status. To evaluate whether pacing-induced changes in the electrocardiogram are related to hemodynamic changes, we analyzed electrocardiograms of patients enrolled in the Pacing Therapies in Congestive Heart Failure trial. The study population consisted of 42 patients, New York Heart Association functional class III-IV with a baseline QRS complex of 175 +/- 32 msec and a PR interval of 196 +/- 33 msec. The mean left ventricular ejection fraction was 0.23. Using high-resolution computer scans, we measured QRS duration of intrinsic and paced electrocardiographs at different times during the study. Results of the electrocardiographic measurements were correlated with functional results. During the crossover period, 34 episodes of biventricular pacing, 27 episodes of left ventricular pacing, and 5 episodes of right ventricular pacing occurred, each at an individual optimized atrioventricular (AV) delay. The only significant difference was that right ventricular pacing increased the QRS width by 40 msec as compared with baseline or biventricular pacing. Functional benefit, as indicated by relative increase of peak oxygen uptake (VO2) compared with baseline, was significantly correlated with shortening of paced QRS width (correlation coefficient, r = 0.55; p <0.05). After 12-month follow-up of 28 patients, we saw a slight, nonsignificant decrease of intrinsic QRS width. With regard to the underlying disease, intrinsic QRS width at baseline and at 12 months was also not significantly different between patients with coronary artery disease and dilated cardiomyopathy. This study found that right ventricular pacing causes an increase in QRS duration in patients with left bundle-branch block, whereas in left ventricular and biventricular pacing, QRS width remains unchanged. Shortening of QRS width is correlated with a pronounced relative increase of peak VO2, and thus may become a noninvasive marker of clinical efficacy. There is no evidence of remodeling of the intrinsic electrocardiogram after 12 months of pacing.

Arrhythmias, Cardiac↗
PubMed2000

Application of hydrostatic pressure facilitates ex vivo adenovirus gene transfer into rabbit aortas.

We investigated whether application of hydrostatic pressure facilitates ex vivo adenovirus gene transfer into rabbit aortas. Assay of beta-galactosidase activity was performed in the aortas subjected to adenovirus encoding LacZ gene (Ad-LacZ) transfer. Application of hydrostatic pressure at 8 atmospheres during Ad-LacZ gene transfer (10(10) pfu/mL, 10 min) to aortic segments resulted in an approximately 4.5-fold increase in transgene efficiency. X-Gal staining showed predominant beta-galactosidase activity in the endothelial and the adventitial cells in the aorta subjected to pressure-supported Ad-LacZ gene transfer. Then we examined the effect of heme oxygenase-1 (HO-1), which catabolizes heme to carbon monoxide and biliverdin, by transferring adenovirus encoding HO-1 (Ad-HO-1) into rabbit aortas using this pressurization system. The Ad-HO-1-infected aortic segment showed a significantly decreased contractile response to phenylephrine compared to the Ad-LacZ-infected aortic segment. Pressure-supported adenovirus gene transfer may increase the feasibility of exploiting intraoperative adenovirus-mediated gene transfer.

Acetylcholine↗
PubMed2000

Pressurization facilitates adenovirus-mediated gene transfer into vein graft.

We investigated whether application of non-distending hydrostatic pressure facilitates gene transfer into vein grafts. An external jugular vein was placed in a chamber with 100 microl adenovirus solution at a titer of 10(10) pfu/ml and was pressurized to up to 8 atm above ambient pressure for 10 min. Histochemical analysis demonstrated a positive transgene expression in all layers of the vessel wall. Gene transfer with 8 atm pressurization resulted in an approximately 50 times higher transgene expression than that without pressurization. Under 8 atm pressurization, the efficiency of gene transfer reached a plateau at 7.5 min. The application of hydrostatic pressure may improve the effectiveness of intraoperative genetic engineering of vein grafts.

Adenoviridae↗
PubMed2000

Eel WT1 sequence and expression in spontaneous nephroblastomas in Japanese eel.

Nephroblastomas spontaneously developing in Japanese eel reared at farms for 5 to 9months after collection from the wild [Masahito et al., Cancer Res., 52 (1992) 2575-2579] were investigated to cast light on the role of Wilms' tumor 1 gene (WT1) in eel kidney tumorigenesis. Cloning of the WT1 counterpart, EWT1, revealed that conservation of an alternative splice II site, located between the third and fourth zinc fingers, was conserved. The zinc finger domain was highly conserved. The transregulator region, sequences corresponding to exons 4 and 5 in WT1, were lacking in EWT1 cDNA. EWT1 was found to be expressed in kidney, testis and spleen and in situ hybridization revealed dark-stained immature cells in elver kidney to be positive. Although no EWT1 gene mutations were found in 38 eel nephroblastomas, 26 polymorphic nucleic acid changes were observed. Aberrant WT1 expression was noted in epithelial (12 out of 27; 44%) and nephroblastic cell histological types (three out of five; 60%) of eel nephroblastomas. On in situ hybridization the EWT1 expressive cells resembled human blastema cells, similar to those in human Wilms' tumor. These data demonstrated strong signals that the EWT1 protein may function in the development of eel kidney and play a role in genesis of nephroblastomas as in mammals.

Amino Acid Sequence↗
PubMed2000

Binding of Ala-scanning analogs of omega-conotoxin MVIIC to N- and P/Q-type calcium channels.

omega-Conotoxin MVIIC binds to P/Q-type calcium channels with high affinity and N-type channels with low affinity. To reveal the residues essential for subtype selectivity, we synthesized Ala-scanning analogs of MVIIC. Binding assays using rat cerebellar P(2) membranes suggested that Thr(11), Tyr(13) and Lys(2) are essential for binding to both N- and P/Q-type channels, whereas Lys(4) and Arg(22) are important for binding to P/Q-type channels. These results suggest that MVIIC interacts with P/Q-type channels via a large surface, in good agreement with previous observations using chimeric analogs.

Alanine↗
PubMed2000

Binding of six chimeric analogs of omega-conotoxin MVIIA and MVIIC to N- and P/Q-type calcium channels.

Replacement of the N-terminal half of omega-conotoxin MVIIC, a peptide blocker of P/Q-type calcium channels, with that of omega-conotoxin MVIIA significantly increased the affinity for N-type calcium channels. To identify the residues essential for subtype selectivity, we examined single reverse mutations from MVIIA-type to MVIIC-type in this chimeric analog. A reverse mutation from Lys(7) to Pro(7) decreased the affinity for both P/Q- and N-type channels, whereas that from Leu(11) to Thr(11) increased the affinity for P/Q-type channels and decreased the affinity for N-type channels. The roles of these two residues were confirmed by synthesizing two MVIIC analogs in which Pro(7) and Thr(11) were replaced with Lys(7) and Leu(11), respectively.

Amino Acid Sequence↗
PubMed2000

Early and delayed Tc-99m ECD brain SPECT in SLE patients with CNS involvement.

We compared early and delayed Tc-99m ECD SPECT scans in 32 SLE patients (Group 1, definite neuropsychiatric disorders; Group 2, minor neurologic symptoms or normal) with those of normal controls by visual inspection and semi-quantitative evaluation. With visual interpretation, 13 out of 14 patients in Group 1 (93%) and 7 out of 18 patients in Group 2 (39%) had diffuse uneven decrease in early scans. Seven patients in Group 2 (39%) who had normal early scans demonstrated focal decrease in the medial frontal lobe in delayed scans. With cerebral region to cerebellar ratios, in early scans, the medial frontal lobe in Group 1 and Group 2 was significantly lower than in normal controls, and lateral frontal lobe and occipital lobes in Group 1 were significantly lower than in normal controls. Nevertheless, in delayed scans, every cortical region except for the parietal lobe in Groups 1 and 2 was significantly lower than in normal controls. The retention rates in all regions in SLE patients were significantly lower than in normal controls. No case showed SPECT improvement on follow-up studies in either group in spite of clinical improvement. Delayed Tc-99m ECD brain SPECT of high sensitivity might be useful in detecting CNS involvement. Although the SPECT findings did not correlate with the neuropsychiatric symptoms, early and delayed Tc-99m ECD SPECT seems to provide useful objective diagnostic information in SLE patients.

Adult↗
PubMed2000

Pulmonary sequestration with myocardial ischemia caused by vasospasm and steal.

We describe patient with a rare pulmonary sequestration with myocardial ischemia in the left coronary artery caused by vasospastic angina and stealing from coronary circulation. The anterior atrial branch from the left circumflex artery gave rise to a large and anomalous vessel in the right posterior lung field. Both the surgical and medical treatment of this pulmonary sequestration improved the control of angina attacks.

Bronchopulmonary Sequestration↗
PubMed2000

Gingerol, isoproterenol and ouabain normalize impaired post-rest behavior but not force-frequency relation in failing human myocardium.

OBJECTIVE: Rest- and stimulation frequency-dependent potentiation of contractile force is blunted in failing human myocardium. These alterations have been related to reduced sarcoplasmic reticulum (SR) Ca(2+)-reuptake and enhanced transsarcolemmal Ca(2+)-elimination by Na+/Ca(2+)-exchange. We investigated whether inotropic interventions that enhance SR Ca(2+)-uptake, or reduce Ca(2+)-elimination by Na+/Ca(2+)-exchange, normalize impaired post-rest and force-frequency behavior in left ventricular muscle strips from failing human hearts. METHODS: We tested the influence of [10]-gingerol which activates SR Ca(2+)-ATPase (10 mumol/l; n = 13), and isoproterenol which activates cAMP-dependent pathways (0.01, 0.1, 1 mumol/l; n = 40) on post-rest and force-frequency behavior. Ouabain which blocks Na+/K(+)-ATPase (0.03 mumol/l; n = 16) was used to test the effects of inhibiting Ca(2+)-elimination by Na+/Ca(2+)-exchange. For comparison, the effects of blocking SR Ca(2+)-uptake by thapsigargin (10 mumol/l; n = 14) were tested. In addition, Ca(2+)-uptake in myocardial homogenates was measured for gingerol (10 mumol/l; n = 6). RESULTS: Gingerol, isoproterenol (0.1, 1 mumol/l) and ouabain exerted significant positive inotropic effects under basal experimental conditions and normalized post-rest behavior. In contrast, force-frequency relation was only slightly improved by gingerol and isoproterenol (0.01 mumol/l). Ouabain and isoproterenol (1 mumol/l) further deteriorated force-frequency relation due to frequency-dependent significant increases in diastolic tension. Thapsigargin exerted negative inotropic effects and significantly deteriorated post-rest and force-frequency behavior. In addition, gingerol increased SR Ca(2+)-uptake significantly in myocardial homogenates. CONCLUSIONS: Inotropic interventions that stimulate SR Ca(2+)-ATPase or inhibit Na+/Ca(2+)-exchange normalize impaired post-rest behavior. Force-frequency behavior is only slightly improved by stimulation of SR Ca(2+)-ATPase but not by inhibition of Na+/Ca(2+)-exchange. This dissociation between post-rest and force-frequency behavior results from diastolic dysfunction at high stimulation rates.

Adult↗
PubMed2000

Long-term results of simultaneous carotid endarterectomy and myocardial revascularization with cardiopulmonary bypass used for both procedures.

OBJECTIVE: Controversy continues about the treatment of patients with a concomitant occlusive disease of the coronary and carotid arteries. Our operative strategy in these patients is to do simultaneous carotid endarterectomy and myocardial revascularization in conjunction with cardiopulmonary bypass with mild hypothermia. We report our experience with this kind of one-stage procedure and its retrospective long-term results. METHODS: From February 1985 to September 1998, 340 patients underwent simultaneous carotid endarterectomy and myocardial revascularization. The average age of the patients was 65.3 years; 45.6% were neurologically symptomatic, and 44.4% had bilateral carotid stenosis. The indication for carotid endarterectomy was lumen diameter reduction of more than 75%, angiographic signs of thrombogenic endovascular morphology, or both. Carotid endarterectomy was performed in conjunction with cardiopulmonary bypass with mild hypothermia, hemodilution, systemic heparinization, and controlled hemodynamics under pulsatile perfusion for additional cerebral protection. RESULTS: There were 16 perioperative neurologic complications (4.7%), 11 permanent deficits (3.2%), and 9 cardiac complications (2.6%). Early mortality was 2.6% (SE 0.8%): 2 patients had a stroke and 2 had a myocardial infarction. The 5-year survival was 78.9% (SE 2.6%), and freedom from ipsilateral stroke and cardiac event were 93.2% (SE 1.5%) and 87.5% (SE 2.1%), respectively. The predictor for early death was age over 70 years, and predictors for late death were age over 70 years, previous myocardial infarction, previous stroke, and bilateral carotid stenosis of greater than 90%. CONCLUSION: On the basis of our long-term results, we believe that simultaneous carotid endarterectomy and myocardial revascularization in conjunction with cardiopulmonary bypass is a method safe enough to prefer its routine use with acceptable low operative risk and satisfactory long-term morbidity.

Aged↗
PubMed2000

Novacor left ventricular assist system versus Heartmate vented electric left ventricular assist system as a long-term mechanical circulatory support device in bridging patients: a prospective study.

OBJECTIVE: Long-term mechanical circulatory support as a bridge-to-transplantation procedure and bridge to recovery is of increasing importance. The implantable left ventricular assist devices, Novacor N100 left ventricular assist system (Baxter Healthcare Corporation, Berkeley, Calif) and TCI HeartMate vented electric left ventricular assist system (Thermo Cardiosystems Inc, Woburn, Mass), have proved to be efficient devices in bridge-to-transplantation settings and for prolonged support. The two systems were compared with regard to reliability and morbidity. METHODS: Between October 1996 and March 1998, a prospective, single-center study was done that included 40 patients, 20 of whom were treated with the Novacor system and 20 of whom were treated with the HeartMate device. The diseases were mainly dilated cardiomyopathy (13/9) and ischemic cardiomyopathy (6/10). There were no statistically significant differences between the two groups regarding age, sex, preoperative clinical blood chemistry values, hemodynamic data, or risk factors. RESULTS: There were no statistically significant differences between the two groups with regard to postoperative hemodynamics, organ recovery, out-of-hospital support, and survival to heart transplantation. Mean duration of support was 235.3 +/- 210 days for the Novacor group and 174.6 +/- 175 days for the HeartMate group and mean out-of-hospital support was 241 +/- 179 days and 166 +/- 152 days for the two groups, respectively. Neurologic complications occurred significantly more often among the Novacor group, whereas the HeartMate group had a higher prevalence of infections and technical problems, which was statistically significant. Survival to transplantation was 65% for the Novacor group and 60% for the HeartMate group. CONCLUSIONS: Most patients had organ recovery with left ventricular assist system support, and a considerable number of patients in both groups underwent transplantation. However, both devices need revision to address the current problems, that is, thromboembolism for the Novacor device and infection and reliability for the HeartMate device.

Female↗