Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 757 records · Page 42Linked to original sources

PubMed1990

[A right atrial thrombus after Fontan procedure--a case report].

A 17-year-old male with tricuspid atresia who underwent a modified Fontan procedure died due to heart failure 4 years and 6 months after operation. At autopsy a thrombus was found in the right atrial appendage. From the experience, it might be recommended to excise the appendage when the modified Fontan procedure leaving the appendage was employed. In addition, anticoagulation therapy as well as regular echocardiographic examination for detecting thrombus formation should be considered after the operation.

Adolescent↗

PubMed1990

Effects of cyclosporin A on T-cell development in organ-cultured foetal thymus.

The effects of cyclosporin A (CsA) on T-cell development were assessed in an organ culture of murine foetal thymus. Applying three-colour flow cytometric analysis, we showed that the agent inhibits the development of mature CD3/T-cell receptor alpha beta (TcR alpha beta)+ cells both in CD4+8- and CD4-8+ populations. CD4-8- cells appeared to be accumulated by CsA. We examined the heterogeneity of CD4-8- cells generated in the organ culture, and defined five subpopulations by the expression of the cell-surface molecules CD3/TcR, J11d and CD25. It has been demonstrated that only the CD3/TcR alpha beta+ J11d- CD25- subpopulation is susceptible to the suppressive effects of CsA among CD4-8- cells, whereas all the other four subpopulations, including CD3/TcR gamma delta+ cells, are resistant. Thus, all of the TcR alpha beta-bearing cells, including CD4-8- cells but none of the TcR alpha beta- cells, are CsA sensitive. Because it is known that CsA inhibits the TcR-mediated signalling events in mature T cells and that signallings mediated via the interaction of TcR with major histocompatibility complex (MHC) molecules on thymic stroma cells are crucial for thymic selection of T cells, these results indicate that TcR alpha beta-bearing CD4-8- cells but not TcR gamma delta-bearing CD4-8- cells undergo thymic positive selection.

Animals↗

PubMed1990

Surfactant replacement therapy with a single postventilatory dose of a reconstituted bovine surfactant in preterm neonates with respiratory distress syndrome: final analysis of a multicenter, double-blind, randomized trial and comparison with similar trials. The Surfactant-TA Study Group.

The effects of a single dose of surfactant TA were assessed in premature neonates (birth weight 750 to 1749 g) with respiratory distress syndrome (RDS) in a multicenter, double-blind, randomized clinical trial. Only neonates with surfactant deficiency and without ultrasonographic evidence of intracranial hemorrhage greater than or equal to grade II were enrolled. Fifty-four patients received surfactant (100 mg of phospholipid per kilogram of body weight) and 46 patients received an air placebo within 8 hours of life. Treatment with this surfactant resulted in a significant reduction in the severity of RDS with a concomitant increase in the proportion of neonates with mild disease. The frequency of pulmonary interstitial emphysema and of pneumothorax was significantly lower in treated neonates compared with control neonates (2% vs 26%, P = .0008, and 7% vs 39%, P = .0004, respectively). The frequency of intracranial hemorrhage was significantly lower in the surfactant group compared with the control group (20% vs 54%, P = .0008) and was also reduced for the smallest neonates in the surfactant group (13% vs 73%, P = .00008). When categorized according to severity of intracranial hemorrhage and severity of bronchopulmonary dysplasia, the surfactant group was at a significant advantage (adjusted Cochran-Mantel-Haenszel X2 = 10.72, P less than .001 and X2 = 4.43, P = .036, respectively). The proportion of neonates surviving without intracranial hemorrhage and/or bronchopulmonary dysplasia was 63% in the surfactant group vs 26% in the control group (P = .0004); as for the smallest neonates, it was 58% in the surfactant group vs 4% in the control group (P = .0002). There were no differences between the groups with respect to the frequency of patent ductus arteriosus (46% vs 37%), pulmonary hemorrhage (6% vs 7%), necrotizing enterocolitis (0% vs 2%), sepsis (4% vs 2%), retinopathy of prematurity (13% vs 22%), or death (15% vs 22%). It is concluded that treatment with the single-dose surfactant regimen used in this study reduces the severity of respiratory distress during the 48 hours after treatment and decreases the major pulmonary morbidity and intracranial hemorrhage in premature neonates with RDS. Further studies are needed to determine whether (1) treatment at birth or as soon as after RDS is diagnosed and (2) the use of multiple dose of this surfactant would result in any additional benefits.

Bronchopulmonary Dysplasia↗

PubMed1990

[A case report of definitive repair for pulmonary atresia and intact ventricular septum associated with aortic valve regurgitation].

A successful definitive repair for a 10-year-old girl with pulmonary atresia and intact ventricular septum (PA.IVS) associated with aortic valve regurgitation is described. The Fontan type repair was not indicated in this case because of the left ventricular dysfunction due to aortic valve regurgitation and inadequate size of the pulmonary artery. Therefore, right ventricular outflow tract reconstruction, Glen shunt and aortic valve replacement were performed despite severe hypoplastic right ventricle (RVEDVI; 33% of normal) and restrictive tricuspid valve (TVD; 48% of normal). Postoperatively, good result was obtained. There is general agreement that biventricular repair could be safely performed using Glenn shunt, when RVEDVI is above 40% of normal and TVD is above 50% of normal in a patient with PA.IVS. Moreover recently including our case, several successful repairs for PA.IVS with more hypoplastic right ventricle and tricuspid valve have been reported. So it is suggested that the right ventricular outflow tract reconstruction and Glenn shunt can be reliably applied for PA.IVS with more hypoplastic right ventricle and more restrictive tricuspid valve. To our knowledge, this is the first successful report of definitive repair (right ventricular outflow tract reconstruction, Glenn shunt and AVR) for PA.IVS associated with AR.

Aortic Valve↗

PubMed1990

[A study of the long-term graft patency using a saphenous vein graft following aorto-coronary bypass surgery].

Long term graft patency after aorto-coronary (A-C) bypass surgery has been reported in the West and the data shows a lower patency rate in saphenous vein grafts (SVG) than internal mammary artery grafts. We studied the long term SVG patency in cases of Japanese patients at our institute, and we have compared our results with those in the West. The subjects, including children, were 211 cases who received A-C bypass surgery using at least one SVG from Jan., 1975 to Sept., 1989. 182 of these cases (examination rate: 86%) received a postoperative angiography one or three months after surgery. The postoperative study took the form of either a selective coronary angiography or a digital subtraction angiography. In 81 cases, using the same two methods, graft patency was reconfirmed from one to eleven years after surgery. Early graft patency including children was 95%. Long term graft patency in the adult cases was 89% from 1 to 2 years (mean: 1.3 years), 94% from 2 to 5 years (mean: 3.2 years), 88% from 6 to 11 years (mean: 7.1 years) following the operation. Six patients died during the post operative follow up period. Two cases were sudden death, one resulted from a reoperation for recurrent angina, two were caused by malignant neoplasm and other was the result of a cerebro-vascular accident. The results correlating the long term graft patency using a SVG and long term mortality were not as negative at our institute as they have been in studies done in the West.

Adult↗

PubMed1990

[The survey on the perinatal variables and the incidence of cerebral palsy for 12 years before and after the application of the fetal monitoring systems].

The effects of electrical fetal monitoring such as cardiotocogram (CTG) and nonstress test (NST) were studied during the years 1975-86 in 6,981 cases (6,893 singletons, 41 twins and 2 triplets). These cases were divided into three groups according to the mode of fetal monitoring. The first group was managed without electrical fetal monitoring (control group). The second was managed mainly with intrapartum fetal monitoring (transitional group) and the third was managed with antepartum and intrapartum fetal monitoring (fully monitored group). The incidence of cerebral palsy (CP) was investigated at the social health center during the same period. The introduction of intrapartum fetal monitoring resulted in a reduction in neonatal asphyxia from 7.0% in the control group to 5.2% and 4.3% in the transitional group and fully monitored group respectively. The perinatal mortality rate showed a significant reduction from 0.61% in the period without antepartum fetal monitoring to 0.31% in the fully monitored group, and this was attributed to the significant reduction in the number of stillbirths. The incidence of CP in the district decreased from 2.2 to 0.2 per 1,000 children during the period studied. In these circumstances, the caesarean section rate increased from 7.0% in the control group to 11.8% in the transitional group but decreased to 9.8% in the fully monitored group. These results showed the clinical and social benefits of electrical fetal monitoring.

Cerebral Palsy↗

PubMed1990

Increased activities of cytosol aminopeptidase and lactate dehydrogenase in serum originate from lymphocytes in necrotizing lymphadenitis.

In three pediatric patients with necrotizing lymphadenitis, cytosol aminopeptidase activity (c-AP; EC 3.4.11.1) in serum was markedly increased to 509, 417, and 191 U/L, respectively (normal range 25-60 U/L). Lactate dehydrogenase (LD; EC 1.1.1.27) was also increased, with LD-3 predominating. The increased concentrations of c-AP and LD presumably originated from the destruction of infected, activated lymphocytes, especially T lymphocytes. Necrotizing lymphadenitis is probably caused by a lymphocytotropic virus.

Aminopeptidases↗

PubMed1990

[Long-term follow-up study of the surgical treatment of pulmonary adenocarcinoma].

The surgical treatment of pulmonary adenocarcinoma was studied on the basis of the postoperative long-term results in 211 cases. The overall five-year survival rate was 42% for adenocarcinoma and 48% for squamous cell carcinoma, and there was no significant difference. In stage I, as the degree of differentiation became lower, the prognosis became poorer. In stage III, the five-year survival rate was 50% for the alveolar cell type and 32% for the well differentiated type. The prognosis was better than in the moderately or poorly differentiated types. The prognosis of T1N0 cases was 79% in T1, but it was significantly lower 39% for T2 cases. Among T3 or T4 cases other than N2, the two-year survival rate was 15%, and the longest survival recorded was 32 months. The results were also poor in 9 cases undergoing extensive surgery, with the two-year survival rate being only 10%. Of the N2 cases undergoing extensive surgery all died within a year, except for one case surviving two years following panpleuro-pneumonectomy. In N2, the prognosis was significantly worse if there were two or more foci of mediastinal lymph node metastasis or if subcarinal lymph node metastasis was present. In the long surviving cases, cancer-bearing survivors were about twice as common as with squamous cell carcinoma. Recurrence was usually by distant metastasis (mainly to the brain), being twice as common as local recurrence. Therefore, in adenocarcinoma the significance of postoperative adjuvant therapy was considered to be greater than in squamous cell carcinoma.

Adenocarcinoma↗

PubMed1990

[Preoperative diagnosis and surgical treatment of tricuspid regurgitation (TR) in patients with acquired valvular heart disease--comparison of Kay's annuloplasty and Carpentier's ring annuloplasty for tricuspid valve surgery].

The purpose of this study is to compare the results of TR repair by using doppler echocardiography. 52 patients who underwent tricuspid repair surgery from 1980 to 1987 were studied. 30 patients received Kay's annuloplasty (K-A group) while 16 patients were repaired with Carpentier's ring annuloplasty (C-E group). A new classification of TRs according to the direction and the area of the regurgitant flow on doppler echocardiogram was applied to the preoperative TRs. In addition to grading the severity of the regurgitations on a four-point scale, the TRs were subdivided into three types according to the direction of the regurgitant flow toward, the interatrial septum (type a), the center of the atrium (type b), and the lateral side of the right atrium (type c). Regurgitation covering more than two of the three areas was recognized as massive TR. In the K-A group, 5 cases showed massive TR and 11 cases showed localized TR preoperatively. Localized TR cases were well controlled in all cases but 4 out of 5 massive TR cases remained third grade and type b postoperatively. In the C-E group, 9 cases showed massive TR and 7 cases showed localized TR. All cases were displayed good control of the regurgitation postoperatively. Postoperative pressure half time of the tricuspid valve orifice treated with the two types of annuloplasty were 108 +/- 25 msec in the C-E group versus 151 +/- 43 msec in the K-A group (p less than 0.001), which indicates the tendency of the K-A group to produce narrowed tricuspid orifice.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

[Ruptured aneurysms of sinus of Valsalva with bicuspid aortic valve--a case report of an aged patient (72 years old)].

A 72-year-old man with ruptured aneurysms of the sinus of Valsalva and a bicuspid aortic valve was operated. Ruptured aneurysms were found in the noncoronary sinus region, and they were opened to the commissure between the anterior cusp and septal cusp of the tricuspid valve. The tissue around the aneurysm was very weak, so closure of the ruptured hole was carried out from the inside of both aorta and right atrium. Ruptured aneurysm of Valsalva is very rare in a aged patient. In this case, it is considered that the bicuspid aortic valve associated with malformations of the aortic cusp caused a weakness of the sinus wall, and this region gradually became aneurysmal.

Aged↗

PubMed1990

[Changes in arterial uterine blood flow velocity waveform during uterine contraction and relaxation in labor].

The arterial uterine blood flow velocity waveform during uterine contraction and relaxation in labor was measured with ultrasonic continuous wave (CW) Doppler device in 44 pregnant women at 37-41 weeks of gestation. The fetal heart rate (FHR) was also recorded by cardiotocogram during labor in every case. 1. Both the resistance index (RI) and pulsatility index (PI) of the arterial uterine blood flow velocity waveform were significantly higher during uterine contraction than during relaxation (p less than 0.005). These increases in RI and PI during contraction were not influenced by the maternal heart rate. The reverse or interrupted end-diastolic flow was demonstrated in 16.3% of the cases. 2. No abnormal FHR patterns were observed in any of the cases except two with early deceleration or mild variable deceleration in which uterine arterial end-diastolic flow was maintained. The fetal conditions did not seem to be influenced by the reduction of arterial uterine blood flow in our study.

Blood Flow Velocity↗

PubMed1989

Effects of undernutrition on the serotonin neuron system in the developing brain: an immunohistochemical study.

The effects of undernutrition during the first 3 weeks of postnatal life on the serotonin neuron system were investigated using a peroxidase-antiperoxidase immunohistochemical method. Undernourishment was induced by increasing the litter size from 6 to 18 mice during the first 3 weeks of postnatal life. At 15 days of age a morphological change (large swelling of serotonin-immunoreactive axons) was noted in various parts of the brain of the undernourished mice with no remarkable changes in dendrites and cell bodies. Quantitative immunohistochemical analysis at 60 days of age showed a significant decrease in serotonin-immunoreactive cell bodies in the nucleus linearis intermedius, the nucleus raphe obscurus, the total raphe system and the subpyramidal region. These results suggest that undernutrition during early postnatal life affected the serotonin neuron system with regional differences.

Animals↗

PubMed1989

1,25-Dihydroxyvitamin D3 inhibits synthesis and enhances degradation of proteoglycans in osteoblastic cells.

The effects of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3), an active form of vitamin D3, on the metabolism of proteoglycans by an osteoblastic cell line MC3T3-E1 were studied. Cells metabolically labeled with [35S]sulfate and/or [3H]glucosamine synthesized large and small dermatan sulfate proteoglycans and heparan sulfate proteoglycan. The incorporation of [35S]sulfate into proteoglycans for 1 h was reduced by 1,25-(OH)2D3 in a dose-dependent manner with a maximum reduction of 40% obtained at 10(-8)M 1,25-(OH)2D3. This effect was observed for all the proteoglycans with the decrease for the large dermatan sulfate proteoglycan most prominent. Treatment with 1,25-(OH)2D3 did not influence the degree of sulfation nor the molecular size of the glycosaminoglycan chains. Thus, the change in the incorporation of [35S] sulfate reflects net change in the synthesis of proteoglycans. When cells were treated with beta-D-xyloside, 1,25-(OH)2D3 also inhibited net synthesis of dermatan sulfate glycosaminoglycan chains on this exogenous substrate suggesting that it decreases the capacity of the cells for glycosaminoglycan synthesis. The incorporation of [3H]glucosamine into hyaluronic acid was also inhibited up to 70% by 10(-8) M 1,25-(OH)2D3. Treatment with 24,25-dihydroxyvitamin D3 did not cause significant changes in the proteoglycan synthesis. Degradation of proteoglycans associated with the cell layer was enhanced by treatment with 1,25-(OH)2D3 at 10(-8) M. Proteoglycans exogenously added to the culture were also degraded with a cell-mediated process which was stimulated by treatment with 10(-8) M 1,25-(OH)2D3. These results demonstrate that 1,25-(OH)2D3 reduces the synthesis and stimulates the degradation of proteoglycans in osteoblastic cells in culture.

24,25-Dihydroxyvitamin D 3↗

PubMed1989

Purification and characterization of 55-kDa protein with 3,5,3'-triiodo-L-thyronine-binding activity and protein disulfide-isomerase activity from beef liver membrane.

Beef liver membranes were shown to have different kinds of 3,5,3'-triiodo-L-thyronine binding proteins including the 55-kDa protein which had been reported to have this activity in many cells by affinity labelling with N-bromoacetyl-3,5,3'-[125I]triiodo-L-thyronine. In order to characterize the molecular features of these binding proteins, the 55-kDa protein was purified from a beef liver membrane fraction abundant in the plasma membrane. The protein was solubilized with 0.5% Chaps and purified by chromatography on gel filtration, hydroxyapatite, and Mono Q anion-exchange columns. The purity was confirmed with reversed-phase HPLC and SDS/PAGE. Consequently, 0.4% of the total proteins in the membrane fraction was recovered as the 55-kDa protein. One fourth of the amino acid composition of this protein was Glx (14.6%) plus Asx (11.7%) and the pI of this protein was 4.5. The purified protein has triiodothyronine-binding activity with a Kd of 57 nM which is similar to the high-affinity binding site of the membranes. The anti-(55-kDa protein) sera specifically recognized the 55-kDa protein of beef, rat and human cells. The immunoglobulin G fraction of the anti-(55-kDa protein) sera inhibited triiodothyronine binding to the beef liver membrane fraction. The purified protein also showed the activity of protein disulfide-isomerase (EC 5.3.4.1) as determined by reactivating scrambled ribonuclease. These data strongly suggested that the multi-functional 55-kDa protein which has triiodothyronine-binding activity and the activity of protein disulfide-isomerase, which is also reported to be the beta subunit of prolyl-4-hydroxylase, glycosylation-site-binding protein of oligosaccharyl transferase and iodothyronine 5'-monodeionidase, could be significant in the action of triiodothyronine towards the target cells.

Amino Acids↗

PubMed1989

Patterns of nucleotide substitutions and implications for the immunological diversity of human immunodeficiency virus.

Human immunodeficiency virus (HIV) exhibits immunological hypervariability, which has been an obstacle to successful production of effective anti-HIV vaccines. In this study, we estimated patterns of nucleotide and amino acid substitutions in the env gene of HIVs, with the aim of finding characteristics of the mechanism which generates the immunological diversity of the env protein of HIVs. We found that nucleotide changes between A and G are predominant compared to those between other nucleotides. Since this feature is consistent with the pattern of nucleotide substitutions of other retroviral genes but is quite different from those of most eukaryotic genes, a high rate of nucleotide substitution between A and G appears to be specific for retroviruses including HIVs. We discuss the biological relationship between this biased substitution and the mechanism generating hypervariability of epitopes on the env protein of HIVs.

Amino Acids↗

PubMed1989

Split tolerance in nude mice transplanted with 2'-deoxyguanosine-treated allogeneic thymus lobes.

To elucidate the acquisition of self tolerance in the thymus, full-allogeneic thymic chimeras were constructed. Athymic C3H and BALB/c nude mice were reconstituted with the thymic lobes of BALB/c and B10.BR fetuses, respectively, that were organ cultured for 5 days in the presence of 2'-deoxyguanosine. T cells in these chimeras were tolerized to the host MHC in both MLR and CTL assays. In contrast, T cells in the chimeras exhibited split tolerance for the thymic MHC haplotype. CTL specific for class I MHC of the thymic haplotype were generated not only from the peripheral T cells of the chimeras but also from thymocytes re-populated in the engrafted thymic lobes. However, T cells in these chimeras responded poorly to the class II MHC of the thymic haplotype in a standard MLR assay. In a syngeneic MLR culture upon stimulation with enriched APC of the thymic haplotype, only 22 to 48% of the responses were mediated by CD4+ cells, and proliferations of CD4- cells were prominent. There were no haplotype-specific suppressor cells detected which would cause the unresponsiveness to the thymic class II MHC. These results indicated that the thymic lobes treated with 2'-deoxyguanosine were defective in the ability to induce the transplantation tolerance for the class I MHC expressed on the thymus, although the same thymic lobes were able to induce the transplantation tolerance for the thymic class II MHC.

Animals↗

PubMed1989

Stabilizing effects of some amino acids on membranes of rabbit erythrocytes perturbed by chlorpromazine.

Hemolysis experiments indicated that glycine (20 mM) remarkably suppressed the chlorpromazine (CPZ)-induced osmotic permeability enhancing effect in rabbit erythrocytes. Lysine and aspartic acid also showed a similar protecting effect at the same concentration. Thus, the acid-base properties of amino acids were not a determining factor in stabilizing the cell membranes perturbed by CPZ. These results suggest that amino acids stabilize the membranes of the erythrocytes by inhibiting the osmotic water transfer from the outside to the inside of the cells. The kinetic studies in isotonic suspensions of erythrocytes indicated that glycine decreased the hemolytic activity of CPZ, and it was suggested that glycine molecules possibly inhibited penetration of CPZ into the cell membranes. The data also showed that the membrane stabilizing action of glycine was not affected by the dissociation of CPZ molecules. The degree of dissociation of glycine molecules was not found to be related to the degree of the protection. The FT-IR spectroscopy data indicated that glycine made the acyl chains of the liposome perturbed by CPZ more orderly.

Amino Acids↗

PubMed1989

Effects of chronic n-hexane exposure on nervous system-specific and muscle-specific proteins.

Two kinds of nervous system-specific and muscle-specific proteins, enolase and S-100 protein, were quantitatively determined in peripheral nerves and skeletal muscles of rats chronically exposed to a neurotoxic solvent - n-hexane. Three groups of animals were exposed to n-hexane vapor at three different solvent concentrations (500 ppm, 1200 ppm, 3000 ppm) for 12 h/day, 7 days/week for 16 weeks. The body weight gain and motor nerve conduction velocity (MCV) in exposure groups show progressively concentration-dependent decreases compared to control values. Histopathological examination also demonstrates the degeneration of peripheral nerves in 3000 ppm- and 1200 ppm-exposed rats. The significant decrease in the amount of S-100 protein in peripheral nerves was observed not only in the high level exposure groups (3000 ppm and 1200 ppm), but also in the lowest level group (500 ppm), although the MCV and morphological examination remained unchanged at this level. In addition, the muscle-specific S-100 protein in 3000 ppm exposed rats' soleus also displayed a significant reduction. In contrast to this, however, enolase isozymes were not significantly changed by either dosage level in both nervous tissue and skeletal muscle. The experiment suggests that beta- and alpha-S-100 proteins which are specifically localized in nervous system and muscles, respectively, are more vulnerable than enolase isozymes under treatment with n-hexane, and may possibly serve as a specific indicator to evaluate the neurotoxic effects. Further research would be worthwhile to elucidate the role of the specific S-100 protein in evaluating the neurologic damage induced by various industrial chemicals.

Animals↗