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Biomedical subjects

S Yamaki

Publications and source records attributed to S Yamaki.

At least 37 records · Page 2Linked to original sources
PubMed1998

Cloning of NAD-dependent sorbitol dehydrogenase from apple fruit and gene expression.

Partial amino acid sequences of NAD-dependent sorbitol dehydrogenase (NAD-SDH) were used to identify a full-length cDNA from apple fruit. This clone consisted of 1,433 bp containing an open reading frame of 1,137 bp that could code for a polypeptide with 379 amino acids. To our knowledge, this is the first report about cloning of NAD-SDH cDNA from a plant source. The deduced amino acids from cDNA revealed 43.7% identity to human NAD-SDH. The activity of this enzyme to convert sorbitol to fructose with the reduction of NAD was certified by the fusion protein of this clone expressed in Escherichia coli. Northern blot analysis showed that the mRNA was expressed in matured apple fruit.

Amino Acid Sequence↗
PubMed1997

Pulmonary hypertension caused by medial hypertrophy associated with aortic stenosis and preductal coarctation.

A 7-month-old female infant with aortic stenosis, preductal coarctation, and pulmonary hypertension underwent operation. Intraoperative lung biopsy revealed marked medial hypertrophy of the pulmonary arterioles. This histopathology is compatible with persistent pulmonary hypertension in the newborn. She is alive about 5 years after the operation, but pulmonary hypertension remains. The pathogenesis is discussed.

Aortic Coarctation↗
PubMed1997

Changes in H(+)-pumps and a tonoplast intrinsic protein of vacuolar membranes during the development of pear fruit.

Vacuolar H(+)-ATPase (V-ATPase) was purified from pear fruit and antibodies were raised against the subunits of 55 and 33 kDa. Antibodies against mung bean H(+)-pyrophosphatase (V-PPase) and radish VM23, which is a tonoplast intrinsic protein (TIP) and a water channel, cross-reacted with the vacuolar membrane proteins of pear fruit. To clarify the roles of these proteins in development of pear fruit, we determined their levels relative to the total amount of protein by immunoblot analysis. The levels of subunits of the V-ATPase increased with fruit development. By contrast, the level of V-PPase was particularly high at the cell-division stage and remained almost the same at other stages. The changes in the activities of V-ATPase and V-PPase corresponded to those in their protein levels. The ratio of V-PPase activity to V-ATPase activity indicated that V-PPase is a major H(+)-pump of the vacuolar membranes of young fruit and that the contribution of V-ATPase increases with fruit development, finally, V-ATPase becomes the major H(+)-pump during the later stages of fruit development. The level of a protein analogous to VM23 (VM23P) was especially high during the active cell-expansion stage in young fruit, and VM23P might, therefore, play an important role in the rapid expansion of cells as a vacuolar water channel. Our results show that the levels of V-ATPase, V-PPase and VM23P change differently and reflect the roles of the respective protein in the development of pear fruit.

Adenosine Triphosphatases↗
PubMed1997

Microatelectasis in patients with secundum atrial septal defect and its relation to pulmonary hypertension.

In patients with secundum atrial septal defect, pulmonary hypertension appears to be attributable to microatelectasis of the lung. To confirm this hypothesis, pulmonary arteries in surgical biopsy specimens from 72 patients with atrial septal defect and pulmonary hypertension were subjected to morphometric examination. Thirty eight of the 72 patients (53%) were found to have microatelectasis of the lung, which suggests that an even higher frequency would have been found if the entire organ had been examined. Atelectatic changes were found in 21 of 39 patients with plexogenic pulmonary arteriopathy (54%), 8 of 15 with musculoelastosis (53%), and 9 of 13 with both of these lesions (69%). No such changes were observed in 5 patients with atrial septal defect who showed thromboembolism-type lesions of the pulmonary arteries. On the other hand, microatelectasis was not observed in another 5 patients with atrial septal defect who did not exhibit pulmonary hypertension. The medial smooth muscles of pulmonary arteries in atelectatic areas were thicker (16.4 +/- 4.0 microns) than those in non-atelectatic areas (10.3 +/- 3.3 microns). The index of pulmonary vascular disease was not significantly different between atelectatic (2.0 +/- 0.6) and non-atelectatic areas (1.9 +/- 0.5). We conclude that in microatelectatic areas, which may tend to develop after respiratory infections in patients with atrial septal defect, hypoxic vasoconstriction of the small pulmonary arteries is liable to occur, which causes hypertrophy of the media. This is likely to lead to the elevation of pulmonary arterial pressure and sustained pulmonary hypertension.

Adolescent↗
PubMed1997

Microangiopathic hemolytic anemia and thrombocytopenia in a child with atrial septal defect and pulmonary hypertension.

Microangiopathic hemolytic anemia and thrombocytopenia have been reported in patients with primary pulmonary hypertension, but not in patients with congenital heart disease even if accompanied with pulmonary hypertension. We present a 7-year-old boy with atrial septal defect and pulmonary hypertension who developed microangiopathic hemolysis and thrombocytopenia. Microangiopathic hemolytic anemia and thrombocytopenia should be remarked as a complication in patients with congenital heart disease.

Anemia, Hemolytic↗
PubMed1997

Different grades of medial hypertrophy and intimal changes in small pulmonary arteries among various types of congenital heart disease with pulmonary hypertension.

Morphometric analysis of small pulmonary arterial changes was performed in three patients with different congenital heart disease with pulmonary hypertension: congenital mitral stenosis (MS), ventricular septal defect (VSD) and transposition of the great arteries (TGA). The material was biopsy or autopsy lung specimens, all having the same degree of elevated pulmonary arterial pressure. Medial thickness was determined by the method of Suwa and Takahashi, and the degree of intimal changes was quantified using the index of pulmonary vascular disease (IPVD) by Yamaki and Tezuka. It was demonstrated that the medial thickening of the small pulmonary arteries was the strongest in the patient with congenital MS, moderate in VSD, and the weakest in TGA, with statistically significant differences between each pair of these three conditions. Interestingly, the order of severity for intimal changes was reversed: it was the severest in TGA and the mildest in congenital MS. We surmise that in patients with TGA, medial hypertrophy is suppressed by sustained vasodilation resulting from the high oxygen saturation of pulmonary arterial blood, while in congenital MS, the media undergoes the severest hypertrophy because of the low oxygen saturation. We also conclude that in TGA intimal changes readily develop in the presence of attenuated media, while in congenital MS, the thickened media seems to prevent intimal changes. From a clinical viewpoint, these results urge us to recommend early surgical intervention in TGA and VSD where severe intimal changes can develop in the absence of extreme medial thickening. It may not be appropriate to extend operation on patients with congenital MS, since strongly thickened media can trigger vasospasms and medial necrosis.

Adolescent↗
PubMed1997

[Pulmonary thromboembolism associated with antiphospholipid syndrome in scleroderma].

A 51-year-old woman was referred to our hospital with dyspnea. Chest roentgenogram on admission showed dilation of the pulmonary arteries and hyperlucency in the lung fields. An ultrasonic cardiographic examination showed that the right atrium and ventricle were dilated. Pulmonary thromboembolism due to left popliteal vein thrombosis was diagnosed by perfusion scintigram of the lung, which showed multiple wedge-shaped defects, and by digital subtraction angiogram, which showed a filing defect in the left popliteal vein. Antiphospholipid syndrome was diagnosed after IgG anticardiolipin antibody was defected. Scleroderma was subsequently diagnosed because the patient exhibited Raynaud's phenomenon and proximal scleroderma. Although closely associated with lupus erythematosus and other lupus variants, antiphospholipid syndrome has not been recognized as a common complication of scleroderma. This is the first report of a patient with pulmonary thromboembolism associated with antiphospholipid syndrome and scleroderma.

Antibodies, Anticardiolipin↗
PubMed1996

High-performance liquid chromatography of peptides on a microspherical carbon column.

The properties of a microspherical carbon column for the separation of peptides and proteins are described. One hundred and thirty-three peptides, with from 1 to 148 amino acid residues, were applied on a carbon column and eluted with a linear gradient of acetonitrile [10-70% (v/v), 30 min] in 0.1% (v/v) trifluoroacetic acid solution. The elution behaviour of the peptides on the carbon column and on an octadecylsilica (ODS) column were compared under the same elution conditions. Relationships between the logarithm of the hydrophobicity of peptides and their capacity factors were approximately linear on both columns, but some exceptions were observed with peptides with aromatic residues, indicating stronger adsorption on the carbon than on the ODS column. These results suggest that the major factor for the separation of peptides on both the carbon and ODS columns is hydrophobic interactions. The stronger adsorption of aromatic side-chains in peptides on the carbon column could be understood by an interaction based on the aromatic or graphitic nature of the surface of the microspherical carbon packings.

Amino Acid Sequence↗
PubMed1996

Reversed-phase liquid chromatography on a microspherical carbon column at high temperature.

The chromatographic conditions for the use of a spherical carbon column at high temperatures up to 160 degrees C are described. The column heating system and the eluate cooling system are also described. Under the conditions studied, it was found that the carbon column at elevated temperature was stable and could be applicable to any compounds that are durable under these conditions. The peptide bonds at this high temperature and at this acidity were still stable enough for analysis, but the indole residues showed poor stability.

Amino Acid Sequence↗
PubMed1996

Histologic study of the small pulmonary arteries in 38 patients with pulmonary atresia and intact ventricular septum.

The structure of the small pulmonary arteries was studied during autopsies performed on 38 patients with pulmonary atresia with intact ventricular septum. The thicknesses of the media of these small pulmonary arteries measured using a quantitative morphometric method varied widely. However, there was a notable tendency toward thinning of the media, especially in neonates. In cases in which the patient had undergone prostaglandin E1 treatment, the media was thinner, which suggests that the longer the treatment, the thinner the media. Intimal lesions were observed in 18 of the 38 patients (47%), including 12 of the 22 neonates (55%). Intimal lesions were also found in the patients with thinner media. Based on these results, we propose that organized thrombus formation and intimal proliferation are more likely to develop in patients with reduced pulmonary blood flow, such as in those with pulmonary atresia and intact ventricular septum. In prostaglandin-treated patients, an imbalance between the markedly thinner median muscle and the relatively higher pulmonary blood flow and pressure may contribute to fibrous intimal proliferation. Small pulmonary arteries with a strikingly thinner media may be vulnerable to higher pressure, predisposing the patient to the development of intimal lesions.

Alprostadil↗
PubMed1995

[Correlation between pulmonary vascular changes and hemodynamic parameters during exercise before and after mitral valve surgery].

Sixteen cases with mitral valvular disease were studied with regard to the correlation between pathological changes in the pulmonary vasculature and pulmonary hemodynamics during exercise before and after surgery. In muscular pulmonary arteries obtained by open lung biopsy, medial wall thickness (MWT) was 13.8 +/- 3.2% and intimal thickness (IT) was 37.3 +/- 13.5%. MWT was correlated with IT (r = 0.60, p < 0.05). Wall thickness in pulmonary veins was 8.21 +/- 1.8%. Preoperative mean pulmonary arterial pressure (MPAP) during exercise was 45.9 +/- 9.4 mmHg, and decreased significantly to 38.1 +/- 11.3 mmHg postoperatively. However, in 4 patients, MPAP during exercise increased after surgery. Pulmonary vascular resistance (PVR) during exercise was unchanged before and after surgery (2.74 +/- 1.90 U.M2-->2.69 +/- 1.3 U.M2). MWT was significantly correlated with preoperative MPAP at rest only. In patients showing an increase of MPAP during exercise postoperatively, mean MWT was 16.2% and mean IT was 47.4%. In conclusion our data suggest that postoperative pulmonary hemodynamics does not improve in patients whose MWT exceeds 15% and IT exceeds 40% and that irreversibility may be due to pulmonary vascular lesions.

Adult↗
PubMed1994

Pulmonary arterial changes in patients dying after a modified Fontan procedure following pulmonary artery banding.

Pulmonary arterial changes were histometrically analyzed in four cases of postoperative death following a modified Fontan procedure in which pulmonary artery banding had previously been performed because of pulmonary hypertension. Case 1 was a 3-year-old girl with corrected transposition of the great arteries (TGA), ventricular septal defect, and double-inlet left ventricle; case 2 was a 6-year-old girl with single ventricle (SV) and complete TGA; case 3 was a 25-month-old boy with SV and double-outlet right ventricle; and case 4 was a 21-year-old man with tricuspid atresia. The cause of death in cases 1, 2, and 3 was pulmonary hypertensive crisis due to postoperative vasoconstriction of the small pulmonary arteries. Medical hypertrophy remained in half of the preacinar small pulmonary arteries although it was not observed in all the intraacinar arteries in cases 1 and 2, even after banding. The postoperative course of case 4 was uneventful despite multiple thromboembolism in the small pulmonary arteries. However, the patient died due to a thrombosed artificial valve. The results suggest that residual medial hypertrophy of the small pulmonary arteries was a major risk factor in these cases. Lung biopsy is recommended to determine the indications for the Fontan procedure in these hemodynamically critical cases.

Adult↗
PubMed1994

Accumulation of autofluorescent yellow lipofuscin in rat tissues estimated by sodium dodecylsulfate extraction.

Autofluorescent yellow lipofuscin accumulated in the older Wistar rat brain, kidney, spleen and testis was successfully extracted by use of 0.5% sodium dodecylsulfate (SDS)/0.05 M phosphate buffered saline (pH 7.4). The extracts contained three fluorophores, one of which corresponded to yellow lipofuscin and showed an excitation maximum at 400 nm and an emission maximum at 620 nm. The SDS extraction method was found suitable for the accurate quantification of lipofuscin in rat tissues. Lipofuscin thus determined accumulated in brain, kidney, spleen and testis with the increase of age of rats. It was found that kidney was the most susceptible tissue in lipofuscin accumulation, and accumulation in male rat kidney was much higher than that in female rat kidney. Accumulation of lipofuscin in rat tissues was slightly dependent on the lipid peroxidation state of the tissues and the dietary conditions: a vitamin E-adequate, vitamin E-deficient, vitamin E-excessive and oil-rich diet, except that the accumulation in male and female rat kidney was significantly enhanced when fed a vitamin E-deficient diet for 7-10 weeks.

Aging↗
PubMed1994

Examination of the extraction methods and re-evaluation of blue fluorescence generated in rat tissues in situ.

Extraction methods for measuring blue fluorescence generated in rat liver and brain in situ were examined. Great care should be taken when the traditional chloroform/methanol extraction method is employed because artificial blue fluorescence is readily produced by subsequent light irradiation, or by passage through a silicic acid column. In contrast, sodium dodecylsulfate (SDS) extraction were found to be suitable since no artificial blue fluorescence was produced by subsequent light irradiation. The levels of blue fluorescence in rat tissues were re-evaluated following SDS extraction. The levels of blue fluorescence in rat liver increased with age, whereas those in rat brain did not. Accumulation of blue fluorescence in the tissues was only slightly enhanced by vitamin E-deficiency. Blue fluorescence in the extracts did not seem to be derived from autofluorescent yellow lipofuscin in situ. The results were not always consistent with earlier observations obtained using the chloroform/methanol extraction.

Aging↗
PubMed1994

Histopathologic findings of lung vessels in five children with primary pulmonary hypertension.

A histopathologic study was carried out on pulmonary vessels of lung tissues from 5 children with primary pulmonary hypertension (PPH), in whom diagnosis was made on the basis of cardiac catheterization. Histological sections of lung were obtained in 4 patients by open lung biopsy and in one patient by closed needle necropsy soon after death. In all cases the vascular diseases were classified as grade 6 of the Heath-Edwards. Morphologic studies of small pulmonary arteries revealed medial hypertrophy (41.0%), intimal cellular proliferation (2.5%), intimal fibroelastic proliferation (36.9%) and medial destructive changes (19.6%) such as dilatation lesions, plexiform lesions, arteritis, or fibrinoid necrosis. Index of pulmonary vascular disease (IPVD) was 1.6 to 3.4 (mean 2.5). The advancement of these pulmonary changes sufficiently explains the extremely poor prognosis of children with PPH.

Adolescent↗
PubMed1993

Pulmonary vascular disease and operative indications in complete atrioventricular canal defect in early infancy.

Pulmonary vascular disease was morphometrically analyzed in 67 patients (mean age, 19 months) with isolated complete atrioventricular canal defect. Complete obstruction of the small pulmonary arterial lumen resulting from acute fibrous proliferation and atrophy of the peripheral arterial media, which were considered absolute operative contraindications, were characteristic in six patients with Down's syndrome. Morphometric analysis of medial thickness revealed that thinning of the media of the small pulmonary arteries is generally observed at around 6 months of age in patients with complete atrioventricular canal defect and that the media in patients who have complete atrioventricular canal defect and Down's syndrome was thinner than that in such patients without Down's syndrome. These results suggest that thinning of the media as a result of two factors--Down's syndrome and aging--facilitates the rapid occurrence of fibrous intimal proliferation. Therefore intracardiac repair is desirable within 6 months of life, before medial thinning, in patients with complete atrioventricular canal defect and Down's syndrome. Excluding patients with absolute operative contraindications, the scores of the index of pulmonary vascular disease in operative survivors were below 2.0 and death occurred when scores were more than 2.2. The pulmonary vascular resistances measured in room air and by the oxygen inhalation and tolazoline tests in patients with operative contraindications were more than 7.3, 3.8, and 6.6 units.m2, respectively. We thus conclude that lung biopsy should be undertaken for patients in whom pulmonary vascular resistance is beyond these values to determine the appropriateness of surgical intervention.

Child↗
PubMed1992

Interpretation of the thiobarbituric acid reactivity of rat liver and brain homogenates in the presence of ferric ion and ethylenediaminetetraacetic acid.

The thiobarbituric acid (TBA) reactivity of rat liver and brain homogenates was characterized to elucidate what kinds of aldehyde species contributed to the reactivity. Characteristic pH dependence of the reactivity with a maximum at around pH 3 and marked enhancement of the reactivity by t-butyl hydroperoxide (t-BuOOH) and ferric ion were similar to those of alkadienals. The amounts of aldehyde species, including alkadienals determined as 2,4-dinitrophenylhydrazones, were high enough to account for the enhanced reactivity. The reactivity was inhibited by ethylenediaminetetraacetic acid (EDTA) but not completely, suggesting the presence of malonaldehyde whose reactivity was not affected by EDTA. The amounts of malonaldehyde determined as 1-(2,4-dinitrophenyl)pyrazole could account for a part of the reactivity in the presence of EDTA. Hence, the TBA reactivity of liver and brain homogenates at around pH 3 in the presence of t-BuOOH and ferric ion may be accounted for by alkadienals and malonaldehyde and that in the presence of EDTA by malonaldehyde.

Animals↗