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Biomedical subjects

T Kamiya

Publications and source records attributed to T Kamiya.

At least 145 records · Page 8Linked to original sources
PubMed1996

Unifocalization for pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries.

To extend the indications for corrective operation in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries, surgical procedures were done to unify the blood sources for pulmonary perfusion. Since December 1985, 50 patients have undergone unifocalization at ages from 2 months to 26 years with a mean of 6 +/- 7 years. In total, 84 staged unifocalization procedures and 5 other palliative procedures were done in 49 patients. These included several operative procedures: simple ligation of major aortopulmonary collateral arteries in 8; pulmonary angioplasty in 29 including reconstruction of the pulmonary arterial tree by direct anastomosis or interposition between the central pulmonary arteries and the intrapulmonary arteries; construction of artificial central pulmonary arteries with use of a xenograft pericardial tube graft in 36 with no native central pulmonary arteries detected; and construction of supplemental central pulmonary arteries also with use of a pericardial tube graft in 10. The pericardial tube graft, if used, was anastomosed to the intrapulmonary arteries on one end and connected to a prosthetic tube on the other end so as to perfuse the reconstructed pulmonary arteries. The anastomosis was made inside the lung through the divided interlobar fissure. Five patients died after operation among those undergoing these 89 preparative operative procedures. Deaths were related either to bleeding caused by anticoagulation therapy administered to prevent thrombosis within the xenograft pericardial tube graft used or to progressive congestive heart failure as a result of an excessive amount of pulmonary blood flow. Twenty-six patients have undergone intracardiac repair after previous unifocalization. In 16 patients the artificial central pulmonary arteries surgically constructed were connected to each other and then an external conduit was placed. In another patient, intracardiac repair and unifocalization could be concomitantly achieved via a median sternotomy. The right ventricle to left ventricle systolic pressure ratio immediately after intracardiac repair in 27 patients ranged from 0.24 to 0.91 with a mean of 0.54 +/- 0.17. One patient (4%) died shortly after intracardiac repair because of thrombosis within the pulmonary arteries. Postoperative catheterization showed that pulmonary vascular resistance was correlated significantly with the number of pulmonary vascular segments functioning rather than with the condition of the central pulmonary arteries. We conclude that surgical unifocalization is a feasible procedure before subsequent intracardiac repair, even in patients with critically hypoplastic or absent central pulmonary arteries.

Adolescent↗
PubMed1996

Simultaneous observation of regional cerebral blood flow and event-related potential during performance of an auditory task.

Reduced amplitude of the P300 component has been reported consistently in patients with neurological and psychiatric disorders. It is unclear, however, how such patients' cognitive dysfunction is related to their P300 abnormality. Further basic knowledge regarding neural substrates for P300 generation is required for gaining an understanding of the pathological significance of the P300 amplitude reduction. To determine the brain structures involved in P300 generation, we observed the event-related potential and the regional cerebral blood flow (rCBF) in 10 normal subjects performing an oddball discrimination of pure tones. The rCBF value was assessed quantitatively with the aid of single photon emission computed tomography using technetium-99m hexamethylpropylene amine oxime. During the task performance, significant activation was observed in the posterior superior temporal and inferior parietal regions of the right hemisphere. In addition, positive correlation of the task-related increase in rCBF with the simultaneously recorded P300 amplitude was observed in the right but not the left posterior superior temporal region. These findings indicate that activation of the right non-verbal auditory area might modulate P300 generation during pure-tone discrimination.

Acoustic Stimulation↗
PubMed1996

Results of unifocalization for pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries: patency of pulmonary vascular segments.

Unifocalization, a surgical technique to unifocalize the pulmonary blood supply in patients with pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries, is a useful preparative operation to extend the indication for corrective surgery. The preoperative and postoperative pulmonary angiograms of 51 patients (aged 3 months-26 years at first unifocalization, 29 males, 22 females), who underwent a total of 96 unifocalizations from December 1985 to July 1994, were studied to assess the effectiveness of each procedure of unifocalization. The procedures of unifocalization were ligation (9), angioplasty (6), direct anastomosis (25), bridging (6), additional central pulmonary artery creation (9), central pulmonary artery creation (36) and thrombectomy (5). Altogether 125 anastomoses were made, and the patency of 101 (80.2%) anastomoses was confirmed, 24 (19.2%) were shown to be occluded. The patency rate of the anastomoses between xenograft rolls and intrapulmonary arteries was 79.5% (70/88), while that between native central pulmonary arteries and intrapulmonary arteries was 83.8% (31/37; N. S.). The patency rate of the anastomoses involving intrahilar arteries was 88.0% (44/50), while that for the group involving extrahilar arteries only was 71.9% (46/64; P < 0.05). It is concluded that 1) unifocalization with the reconstruction of central pulmonary arteries using a pericardial roll is a useful method for patients with absent or hypoplastic central pulmonary arteries, 2) it is preferable to divide the fissures of lung in anastomosing pulmonary arteries of arborization abnormalities.

Adolescent↗
PubMed1996

A new murine lymphocytotoxic monoclonal antibody recognizing HLA-A2, -A28 and -A9.

Monoclonal antibodies recognizing polymorphic as well as monomorphic epitopes on HLA antigens are important tools for understanding the immunobiology of HLA molecules. We immunized BALB/c mice with a HLA-A2 transfectant and screened for hybridomas which reacted with a HLA-A2 transfectant but not with a HLA-B75 transfectant. After subcloning by limiting dilution four times, a hybridoma secreting a monoclonal antibody (mAb) (IgG 2a, kappa) designated 1-145 was established. 1-145 reacted with Epstein-Barr virus transformed B lymphoblastoid cell lines (B cell lines) which expressed HLA-A2, -A28, -A23 and -A24. The titer of 1-145 in culture supernatant against HLA-A2 and -A28 antigens was similar and the titer against HLA-A23 was lower. 1-145 reacted with cells expressing HLA-A24 but the titer against HLA-A24 antigens was even lower than that against HLA-A23 antigens. The HLA-A24 antigens on the peripheral blood lymphocytes were not detected by 1-145 possibly due to the lower expression compared to the B cell lines. These differences of the titers were reflected to microlymphocytotoxicity assay in which 1-145 culture supernatant lysed all PBLs expressing HLA-A2,-A28 and -A23 but did not lyse PBLs expressing HLA-A24. Published deduced amino acid sequence data of HLA class 1 molecules indicate that Lys in position 127 may be critical for 1-145 binding.

Amino Acid Sequence↗
PubMed1996

Hepatocyte volume as an indicator of hepatic functional reserve in cirrhotic patients with liver tumours.

Using computed tomography (CT), measurements of whole liver volume have been used for the assessment of pre-operative functional reserve in cirrhotics. However, measurements of hepatocyte volume, which exclude stromal fibrous tissue, are considered to more directly reflect hepatic functional reserve. We investigated the relationship between total hepatocyte volume and each of the parameters of conventional liver function. Indocyanine green (ICG) tests and blood analyses for the assessment of liver function were performed prior to surgery in cirrhotic patients with liver tumours. Pre-operative liver volume was determined by integrating images of each liver area obtained by CT. Liver area was measured by an image processing program that traced the profile of the liver image while excluding the tumorous area. Sections of normal tissue stained by the haematoxylin-eosin method, were obtained from the resected liver. Using these sections, a hepatocyte area: whole tissue area ratio was calculated using the image processing program, by tracing the profiles of the hepatocyte nodules. The total volume of hepatocytes was then calculated by multiplying the liver volume by this ratio. The hepatocyte volume per unit bodyweight was significantly correlated with ICG tests and with many other parameters of normal liver function. However, the liver volume per unit bodyweight was correlated only with the plasma ICG disappearance rate and with the blood platelet count. These observations suggest that the functional reserve of the cirrhotic liver is assessed more precisely by hepatocyte volume than by liver volume.

Adult↗
PubMed1996

T wave alternans in idiopathic long-QT syndrome: insight from body surface mapping.

Body surface mapping was recorded during T wave alternans in two patients with idiopathic long QT syndrome. Eighty-seven lead ECGs of two consecutive beats during T wave alternans demonstrated that alternating changes in the morphology and polarity of the T wave existed mainly in the left frontal chest. The QRST isointegral maps of the same two consecutive beats showed alternation of a large negative area appearing mainly in the left frontal chest. These results indicate that T wave alternans in the two patients were related to alternate heterogeneous prolongation of the action potential duration in this region.

Action Potentials↗
PubMed1996

Secretion of active Fc fragments of immunoglobulin E directed by the yeast invertase signal sequence in mammalian cells.

The human Fc fragments of immunoglobulin E (IgE-Fc) expressed in the mammalian COS cells, those mainly consisting of C epsilon 3-C epsilon 4 chains with or without Cys-328 known to be responsible for interchain disulfide bonding, were secreted into the culture medium directed by the yeast Saccharomyces cerevisiae invertase (SUC2) signal sequence (SUC2/Ig2 or SUC2/Ig, respectively) as well as by the human interleukin 2 receptor alpha chain signal sequence (IL2R/Ig2 or IL2R/Ig, respectively). For the binding activity to the human soluble alpha chain of high affinity receptor for IgE, IgE-Fc with Cys328, SUC2/Ig2 and IL2R/Ig2, were active but had smaller activity than native IgE. By comparison IgE-Fc without Cys328, SUC2/Ig and IL2R/Ig, showed lower activity than SUC2/Ig2 and IL2R/Ig2. Immunoprecipitation analysis revealed both SUC2/Ig and SUC2/Ig2 had molecular weights (M(r)s) and degrees of glycosylation similar to IL2R/Ig and IL2R/Ig2, respectively. These results suggested that in mammalian cells the SUC2 signal sequence was functional in directing the heterologous multimeric proteins to the endoplasmic reticulum, resulting in secretion of the active proteins. This finding might show merits on heterologous protein secretion systems.

Amino Acid Sequence↗
PubMed1996

Myocardial metabolic changes in hypertrophic cardiomyopathy.

UNLABELLED: We evaluated myocardial blood flow, glucose and oxygen metabolism using PET in hypertrophic cardiomyopathy (HCM). METHODS: PET studies using 18F-fluorodeoxyglucose (FDG) and 11C-acetate were performed at rest in patients with HCM and normal subjects as a control group. The metabolic rate of glucose (MRGlu), K mono value as a marker of oxidative metabolism, and myocardial blood flow were estimated from serial dynamic FDG and 11C-acetate PET studies. RESULTS: Myocardial blood flow (%) did not differ significantly in hypertrophic and nonhypertrophic myocardium (90.3 +/- 3.1 versus 91.7 +/- 3.4). The MRGlu in hypertrophic myocardium, however, was lower than that of hypertrophic and normal myocardium (0.44 +/- 0.10 versus 0.52 +/- 0.15 and 0.53 +/- 0.15 mumole/min/g, respectively, p < 0.05). The K mono values were also lower in hypertrophic myocardium than in nonhypertrophic and normal myocardium (0.05 +/- 0.010 versus 0.066 +/- 0.0011 and 0.065 +/- 0.017 per min, respectively, p < 0.05). The %FDG/%perfusion values in hypertrophic myocardium did not differ significantly from those in nonhypertrophic myocardium (0.96 +/- 0.10 versus 1.02 +/- 0.07). CONCLUSION: Myocardial ischemia at rest is observed less frequently in patients with HCM. Impairment of oxidative and glucose metabolism may precede decreased blood flow. Primary metabolic impairment is considered to be dominant in hypertrophic myocardium.

Acetates↗
PubMed1996

Unsusceptibility of recombinant human Fc fragments of immunoglobulin E to thrombin.

Human immunoglobulin E (IgE) contains a potential recognition sequence for thrombin protease cleavage at N-terminal end of C epsilon 3 domain responsible for binding to alpha chain of high affinity Fc receptor for IgE (Fc epsilon RI alpha), but it remains unknown for the enzyme susceptibility. The human Fc fragments of IgE (IgE-Fc), consisting of C epsilon 2' (Ala329)-C epsilon 3-C epsilon 4 chains (Fc') and of C epsilon 2' (Thr315-Ala329)-C epsilon 3-C epsilon 4 chains (F(c')2), were expressed in the mammalian COS and Chinese hamster ovary (CHO) cells by placing the IgE-Fc cDNA under the control of the cytomegalovirus (CMV) promoter. Under nonreducing condition F(c')2 was not cleaved by thrombin protease as well as native IgE. Neither treatment of F(c')2 with final 0.1% 2-mercaptoethanol at boiling point for 5 min, with a sulfhydryl-reactive biotin derivative, by which monomers in COS-derived F(c')2 preparations were biotinylated at Cys328, nor with neuraminidase, affected the accessibility to the enzyme. These results suggested that F(c')2, either dimeric or monomeric, had compact conformations.

Animals↗
PubMed1996

[Two siblings with familial schizencephaly--report of a family and review in relation to clinical features and neuroradiological findings].

We examined 2 siblings with schizencephaly. A 23-year-old female (Case-1) had a mild left hemiparesis, and her 25-year-old brother (Case-2) presented a quadriplegia. Both cases achieved a borderline intellectual level and both had seizure disorders. The magnetic resonance imaging (MRI) of Case-1 revealed thickened gray matter around the fused schizencephalic clefts in the bilateral frontal lobes, mild ventricular enlargement and absence of the septum pellucidum. And, the MRI result of Case-2 disclosed similar but more severe abnormalities. The positron emission tomography (PET) using 18F-Fluoro-2-deoxy-D-glucose of Case-1 demonstrated focal hypermetabolic activity in the ectopic gray matter with the absence of epileptic discharges on the electroencephalogram on the day of PET study. And the single photon emission computed tomography (SPECT) using 123I-N-isopropyl-p-iodoamphetamine of Case-1 delineated focal hyperperfusion in the same lesions. The PET and SPECT findings are unique, since previous reports have indicated focal hypoperfusion and hypometabolism in abnormal gray matter. Familial schizencephaly is a very rare malformation, and this is the first report of that in Japan. Further evaluation in similar cases is needed to determine the pathophysiology of this anomaly.

Adult↗
PubMed1995

Effects of verapamil and propranolol on early afterdepolarizations and ventricular arrhythmias induced by epinephrine in congenital long QT syndrome.

OBJECTIVES: This study used monophasic action potentials to investigate the effects of verapamil and propranolol on epinephrine-induced repolarization abnormalities in congenital long QT syndrome. BACKGROUND: Early afterdepolarizations have been suggested to play a significant role in QT prolongation and ventricular arrhythmias in congenital long QT syndrome. Calcium channel blocking as well as beta-adrenergic blocking agents are reported to be effective in the management of this syndrome. METHODS: Monophasic action potentials from 2 to 4 sites were recorded simultaneously in eight patients with the long QT syndrome (22 sites) and in eight control patients (23 sites) and were obtained during constant atrial pacing 1) before epinephrine infusion; 2) during epinephrine infusion (0.1 microgram/kg body weight min); 3) after verapamil injection (0.1 mg/kg) during epinephrine infusion; and 4) after both propranolol (0.1 mg/kg) and verapamil injections. RESULTS: Early afterdepolarizations were recorded in two of the eight patients (2 of 22 sites) during the control state. During epinephrine infusion, early afterdepolarizations were recorded in six patients (six sites), and ventricular premature complexes were induced in three and torsade de pointes in one. Epinephrine prolonged 90% monophasic action potential duration from 348 +/- 48 (mean +/- SD) to 381 +/- 49 ms (22 sites, p < 0.0005) and increased the dispersion of action potential duration (difference between the longest and shortest action potential duration) from 36 +/- 20 to 64 +/- 34 ms (p < 0.005). Verapamil eliminated (two sites) or reduced (four sites) early afterdepolarizations and abolished ventricular premature complexes in two of the three patients as well as suppressing torsade de pointes. Verapamil shortened the action potential duration to 355 +/- 28 ms (p < 0.01 vs. epinephrine) and decreased the dispersion to 44 +/- 19 ms (p < 0.05 vs. epinephrine). Propranolol further eliminated (two sites) or reduced (two sites) early after depolarizations, abolished ventricular premature complexes in the remaining one patient and further shortened the action potential duration to 337 +/- 32 ms (p = 0.09 vs. verapamil). In the control patients, none of the early afterdepolarizations, ventricular arrhythmias or marked prolongations of action potential duration were induced by epinephrine, and neither verapamil nor propranolol changed repolarization variables. CONCLUSIONS: These results indicate that both verapamil and propranolol can improve repolarization abnormalities induced by epinephrine in congenital long QT syndrome.

Action Potentials↗
PubMed1995

Analysis of S-layer proteins of Lactobacillus brevis.

The presence of S-layer proteins in Lactobacillus brevis was examined by SDS-PAGE analysis. Thirty six out of a total of 41 L. brevis strains possessed S-layer proteins of molecular masses ranging from 38 to 55 kDa. Western blot analysis using antisera raised against whole cells of S-layer protein-carrying strains demonstrated the heterogeneity of L. brevis S-layer proteins. No clear relationship was observed between the presence of S-layer proteins or their immunological characteristics and the physiological activity of L. brevis as a beer spoilage organism.

Bacterial Proteins↗
PubMed1995

Use of the bidirectional Glenn procedure in the presence of forward flow from the ventricles to the pulmonary arteries.

BACKGROUND: Relative regression of the pulmonary arterial size has been reported after a conventional bidirectional Glenn procedure. Maintaining a supplemental pulmonary flow could be of surgical value unless the option also militates against the efficacy of the partial right heart bypass. METHODS AND RESULTS: Twenty-seven patients considered unsuitable for a Fontan-type procedure underwent a bidirectional Glenn procedure in the presence of forward flow from the ventricles to the pulmonary arteries, the flow being maintained through the pulmonary trunk in 22 or a systemic-to-pulmonary shunt in 5. There was one surgical death due to atrioventricular valvular regurgitation. Subsequently, 9 patients have successfully undergone a total cavopulmonary connection 2.6 +/- 1.9 years after the initial procedure. Preoperative and postoperative catheterizations revealed changes in arterial oxygen saturation (75 +/- 11% compared with 83 +/- 7%, P < .001) and end-diastolic volumes of the systemic ventricles (from 238 +/- 92% to 188 +/- 97% of the expected normal volume, P < .01), whereas no difference was detected in the mean cross-sectional area of the right and left pulmonary arteries compared with the expected normal value for the right pulmonary artery (from 76 +/- 21% to 81 +/- 20%) or in the ventricular ejection fraction (from 53 +/- 8% to 50 +/- 14%). The relative regression or growth of the pulmonary arterial size was statistically related to the size of the channel for forward flow. CONCLUSIONS: Maintenance of forward flow from the ventricle provides a feasible means, when performing a bidirectional Glenn procedure, of protecting against regression of pulmonary arterial size as well as off-loading the ventricles and improving arterial oxygen saturation.

Adolescent↗
PubMed1995

Poly(ADP-ribose) polymerase activity in various U937 cell subclones with different susceptibility to HIV-1 infection: its dramatic decrease following persistent virus infection.

Poly(ADP-ribose) polymerase, a nuclear enzyme, is suggested to be involved in apoptotic cell death. It is also known that apoptotic cell death following HIV-1 infection is the most important feature of AIDS pathogenesis. Thus, to evaluate the relations between the enzyme and HIV-1 infection, we examined the enzyme activity of several subclones of human promonocytic cell line U937, which showed different susceptibility to HIV-1 infection. The nuclear extracts of two "high type clones" (possessing high susceptibility to HIV-1 infection) contained approximately 4 to 7-fold less enzyme than two low type clones when assayed under a full activation of enzyme. Parent clone, possessing an intermediate susceptibility to HIV-1, showed an intermediate enzyme level, suggesting that low level of this enzyme in cells is important for an effective infection of HIV-1. Furthermore, when these U937 subclones persistently infected with HIV-1 were examined, a dramatic decrease of the enzyme activity, reaching 2 to 16% of uninfected cells, was observed in all of these clones. The levels of poly(ADP-ribose) glycohydrolase in these clones were relativity unchanged. Activity gel analysis and immunoblotting of the enzyme in the clones revealed that the low enzyme activities observed in uninfected "high type clones" and all HIV-1-infected clones were due to a marked decrease of the enzyme protein itself. All of these results suggest that HIV-1 infection involves some mechanism to downregulate cellular poly(ADP-ribose) polymerase and that a lower level of the enzyme may be essential for an effective production of the virus and/or for a stable virus/host interaction.

Acquired Immunodeficiency Syndrome↗