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Biomedical subjects

S Yamaki

Publications and source records attributed to S Yamaki.

At least 19 recordsLinked to original sources
PubMed2005

Gypsy embryo specifies ovule curvature by regulating ovule/integument development in rice.

The embryo position in a seed is stable in most plant species, indicating the existence of a strict regulatory mechanism that specifies the embryo position in the seed. To elucidate this mechanism, we analyzed the gypsy embryo (gym) mutant of rice, in which the position of the mature embryo in the seed is altered at a low frequency. Analyses of early embryogenesis and ovule development showed that the ectopic embryo was derived from an ill-positioned egg cell, which resulted from the incomplete curvature of the ovule. Although the development of both the inner and outer integuments was impaired, the ovule curvature was associated closely with the extent of inner integument growth. Therefore, inner integument development controls ovule curvature in rice. The expression patterns of OSH1 and OsMADS13 indicated that, in gym, a small number of indeterminate cells are maintained on the style side of the ovule and then in the integument primordium at a low frequency. The prolonged survival of these indeterminate cells disturbs normal integument development. The gym fon2 double mutant suggests that GYM and FON2 are involved redundantly in floral meristem determinacy. Possible functions of the GYM gene and the ovule developmental mechanism are discussed.

Gene Expression Profiling↗
PubMed2001

Reduction in recalcitrant pulmonary hypertension after operation for atrial septal defect.

We present the case of a patient with atrial septal defect and severe pulmonary hypertension with pulmonary artery peak pressure greater than 110 mm Hg. Open lung biopsy was done prior to the corrective operation, and pathological findings in the small pulmonary arteries included "musculoelastosis" and complete occlusion of 70% of these small arteries and arterioles. The atrial septal defect was closed, and long-term oral prostacyclin therapy was initiated. Pulmonary artery peak pressure decreased to 65 mm Hg 2 years after the operation. This case demonstrates that in a patient with 70% complete occlusion of small pulmonary arteries and arterioles resulting from "musculoelastosis," not only is surgical intervention possible but also pulmonary artery pressure decreases in the long term after operation.

Adult↗
PubMed2001

Molecular cloning of beta-galactosidase from Japanese pear (Pyrus pyrifolia) and its gene expression with fruit ripening.

We have cloned a cDNA fragment encoding a beta-galactosidase from Japanese pear (Pyrus pyrifolia) fruit (JP-GAL). It contained an untranslated sequence of 182 nucleotides at the 5' end, a presumptive coding sequence of 2,193 nucleotides and an untranslated sequence of 268 nucleotides including a polyadenylation signal and a poly (A) tail at the 3' end. It encoded a protein with a calculated molecular weight of 80.9 kDa which consists of 731 amino acids. Both the nucleotide and the deduced amino acid sequences showed a 98% sequence identity with that obtained from the apple beta-galactosidase cDNA. The peptide sequence obtained from the purified Japanese pear beta-galactosidase III matched the deduced amino acid sequence of SVSYDHKAIIINGQKRILISG (amino acid 25-45). Northern blot analysis showed that the probe derived from JP-GAL hybridized to a single 2.6 kb RNA. The mRNA was detected solely in the fruit; none was detected in the buds, leaves, roots or shoots of the Japanese pear. The steady-state level of the beta-galactosidase mRNA was measured during fruit ripening in three cultivars, Housui, Kousui (early ripening) and Niitaka (late ripening). The results showed that regardless of the cultivar, no JP-GAL mRNA was detected in the immature fruit. Increment of the mRNA level with fruit ripening coincided with the increase in the beta-galactosidase III activity. Our results showed that the expression of JP-GAL correlated with fruit softening and JP-GAL may be beta-galactosidase III.

Amino Acid Sequence↗
PubMed2001

[Indication for lung biopsy and usefulness of lung biopsy].

The criteria of open lung biopsy for operative indication were determined on the basis of hemodynamics in each congenital cardiac anomalies with pulmonary hypertension. More than 10.6, 8 and 8 units. m2 of pulmonary vascular resistance (PVR) were considered as indication for open lung biopsy in the patients with complete transposition of the great arteries, complete atrioventricular canal defect and atrial septal defect respectively. Lung biopsy should be done in patients with ventricular septal defect when PVR is more than 8 units. m2 and if it is greater than 4 with the oxygen inhalation test or 6 with the Tolazoline test. The usefulness of lung biopsy was also emphasized on the basis of the postoperative result in which lung biopsy diagnosis has been done.

Biopsy↗
PubMed2000

Pulmonary vascular disease in Down's syndrome with complete atrioventricular septal defect.

We sought to determine the predisposing factors of pulmonary vascular disease (PVD) in complete atrioventricular septal defect. Down's syndrome is considered a risk factor for PVD, but the progression of PVD differs in each case. Morphometric analysis in autopsied hearts showed that Rastelli type A morphology had a narrower left ventricular outlet and a wider right ventricular outlet than did type C. In 81 consecutive patients with Down's syndrome who underwent cardiac catheterization, we estimated the following variables: Rastelli subtypes, pulmonary vascular resistance, pulmonary-to-systemic flow ratio, patients' age, and operative outcome. The hemodynamic variables in those <1 year old did not differ between the groups with type A and type C. However, all 5 patients with fatal pulmonary hypertension in early infancy had type A morphology. The lung histology revealed that 3 of these patients already had irreversible PVD. At >/=1 year old, those with type A showed a significantly higher pulmonary vascular resistance (p <0.001) and a lower pulmonary to systemic flow ratio (p <0.05) than did those <1 year old. In contrast, neither of these variables in the type C group differed between those >/=1 and <1 year old. Moreover, those with type A had a greater risk of being contraindicated for surgical repair (p <0.05). We suspect, therefore, that type A morphology is an independent risk factor for PVD in those with Down's syndrome associated with this anomaly. This hemodynamic influence could become obvious once patients are >/=1 year old. It may also sometimes result in irreversible PVD even in early infancy.

Adolescent↗
PubMed2000

Pulmonary vascular changes induced by congenital obstruction of pulmonary venous return.

BACKGROUND: Pulmonary venous obstruction (PVO) induces pulmonary arterial hypertension, as well as pulmonary venous hypertension, and jeopardizes the repair of cardiac lesions. METHODS: Four cases of congenital mitral stenosis and 4 cases of cor triatriatum (Lucas type A), ages ranging from 2 months to 16 years, were histologically examined on pulmonary vasculature. Histometrical analysis was performed on medial thickness and intimal changes of both pulmonary arteries and veins. For comparison, the examination of pulmonary vasculature in ventricular septal defect (VSD) cases was also performed. RESULTS: Medial thickening and intimal fibrosis, in both pulmonary arteries and veins with widespread lymphangiectasia, were characteristic vascular changes of PVO cases. Medial thickness of pulmonary arteries was correlated with preoperative pulmonary arterial pressure (PAP) (r = 0.77, p = 0.03 for systolic PAP), and greater than that of VSD cases. Medial thickness of pulmonary veins was also greater in PVO cases. Intimal fibrosis of pulmonary arteries and veins was seen extensively at the advanced ages, whereas no plexiform lesions or more advanced stages of pulmonary vascular disease were present. CONCLUSIONS: Congenital PVO induced progressive medial thickening and intimal fibrosis in pulmonary arteries and veins accompanied by lymphangiectasia. However, no plexiform lesions or more advanced stages of pulmonary vascular disease were present, which may explain the reversibility of pulmonary hypertension due to congenital PVO.

Adolescent↗
PubMed2000

Purification and characterization of a NAD+-dependent sorbitol dehydrogenase from Japanese pear fruit.

NAD+-dependent sorbitol dehydrogenase NAD-SDH, EC 1.1.1.14) from Japanese pear fruit was purified to apparent homogeneity (single band by SDS-PAGE with silver staining), and had a specific activity of 916.7 nKatal/mg protein. The molecular of the native enzyme was calculated to be 160 kDa by gel filtration, whereas SDS-PAGE gave a subunit size of 40 kDa, indicating that the native enzyme is a homotetramer. The protein immunologically reacted with an antibody raised in rabbit against the fusion protein expressed in E. coli harboring an apple NAD-SDH cDNA. The Km, values for sorbitol and fructose were 96.4+/-8.60 and 4239+/-33.5 mM, respectively, and optimum pH for sorbitol oxidation was 9.0 and 7.0 for fructose reduction. Pear NAD-SDH had a very narrow substrate specificity, that is, sorbitol, L-iditol, xylitol and L-threitol were oxidized but not any of the other alcohols tested. These data suggest the structural importance of an S configuration at C-2 and an R configuration at C-4 in the substrate(s). Its enzymatic activity was strongly inhibited both by heavy metal ions such as mercury, and by thiol compounds, such as L-cysteine. However, the addition of zinc ion reversed the enzyme inactivation caused by addition of L-cysteine.

Blotting, Western↗
PubMed2000

Purification and characterization of two sucrose synthase isoforms from Japanese pear fruit.

Two isoforms (SS I and SS II) of sucrose synthase (SS; EC 2.54.1.13) were purified from Japanese pear fruit and their properties were compared. SS I mainly appeared in young fruit and SS II mainly in mature fruit. SS I and SS II were purified to the specific activity of 3.37 and 4.26 (units (mg protein)(-1)), respectively. The MW of native and subunit proteins of SS I and SS II were almost the same and both SSs seemed to be a tetramer composed of an 83 kDa polypeptide. However, the ionic charges of the native proteins and the kinetic parameters of SSs were different. Specifically, the Km value for UDP-glucose in SS I was the same as that for UDP, while the Km value for UDP-glucose in SS II was less than that for UDP. SS II easily reacted for sucrose synthesis than sucrose cleavage compared with SS I. Therefore, it is considered that SS I and SS II play different roles in the utilization of carbohydrate in young and mature fruit, respectively.

Fruit↗
PubMed2000

Extremely thickened media of small pulmonary arteries in fatal pulmonary hypertension with congenital heart disease--a morphometric and clinicopathological study.

There are patients with congenital heart disease and fatal pulmonary hypertension in whom the medial hypertrophy of the small pulmonary arteries is quite beyond the extent of ordinary cases of hypertension, a condition described as pulmonary hypertension with extremely thickened media of small pulmonary arteries (PH/ETM). Lungs from 6 infants, all younger than 2 years of age, who had congenital heart disease and fatal pulmonary hypertension, were analyzed by accurately measuring the media using Suwa's method. In PH/ETM, the media of the small pulmonary arteries was shown to be not only unusually thick, but extending toward the periphery, whereas the intimal changes were unexpectedly mild. In the PH/ETM group, the % wall thickness at a diameter of 50 microm (%Tw(50)), determined from regression analysis, was 23.2+/-1.3%, which was significantly higher than in either the control (10.3+/-1.2%) or ventricular septal defect group (18.9+/-1.6%). In persistent pulmonary hypertension of the newborn (PPHN), it was 22.3+/-1.8%, not significantly different from PH/ETM. The striking medial hypertrophy in PH/ETM and PPHN was apparently confined to small pulmonary arteries and in both conditions is likely to be the result of maldevelopment of these arteries. Surgical intervention may trigger a critical elevation of the pulmonary arterial resistance.

Autopsy↗
PubMed1999

Structural relationship of lambda-type light chains with AL amyloidosis.

Three human amyloidogenic Bence Jones proteins, NIG76 VlambdaII, NIG204 VlambdaI, and NIG250 VlambdaV, were characterized. In a comparative study, three amino acids, Ser-25a, Thr-68, and Val-95, were found to be common to amyloidogenic proteins of the VlambdaII subgroup. NIG204 had an insertion of Pro residue following position 30 (30a). Proteins having an insertion at this position are invariantly amyloidogenic. NIG250 had a characteristic VlambdaV VL domain, with Mcg+ and KERN+ CL domain isotypes. Following the protein DEL, this is the second example of this subgroup. No common residue is found in the other subgroup proteins but unique substitutions do occur. It would seem that any substitution that causes an alteration in the protein conformation may lead to its being more prone to association with the amyloid processes.

Amino Acid Sequence↗
PubMed1999

Progressive pulmonary vascular disease after pulmonary artery banding and total correction in a case of ventricular septal defect and pulmonary hypertension.

A 7-month-old infant with ventricular septal defect and pulmonary hypertension underwent pulmonary artery banding, which resulted in a decrease in the pulmonary arterial peak pressure from 102 to 54 mmHg. Lung biopsy findings showed at most an early grade 3 Heath-Edwards classification, and an index of pulmonary vascular disease of 1.4, both of which indicated operability for total correction. Small pulmonary arteries less than 100 microns in diameter, however, showed marked hydropic changes in the medial smooth muscle cells. Total correction was performed at the age of 2 years, but the pulmonary arterial pressure failed to decrease. A lung biopsy taken just after the closure of the ventricular septal defect contraindicated operability due to progressive pulmonary vascular disease at a grade 6 Heath-Edwards classification and an index of pulmonary vascular disease of 2.4. The patient died at 8 months after the operation, and an autopsy revealed still more advanced pulmonary vascular disease at a grade 6 Heath-Edwards classification and an index of pulmonary vascular disease of 2.8. The pathogenesis of arterial changes is discussed.

Disease Progression↗
PubMed1999

Vacuolar H(+)-pyrophosphatase purified from pear fruit.

A vacuolar H(+)-translocating inorganic pyrophosphatase was purified from pear fruit through selective detergent treatments, Superose 6 and Mono Q column chromatography. The specific activity of the purified enzyme was 850 mumol h-1 mg protein-1. The Mr of V-PPase was 66 kDa by SDS-PAGE and the polypeptide cross-reacted with the antiserum against V-PPase of mung bean. The purified V-PPase was stimulated by potassium and inhibited by calcium and N, N'-dicyclohexylcarbodiimide.

Blotting, Western↗
PubMed1999

Structural relationship of kappa-type light chains with AL amyloidosis: multiple deletions found in a VkappaIV protein.

Two amyloidogenic Bence Jones proteins (Am37 VkappaIV and NIG1 VkappaI) and one non-amyloidogenic protein (NIG26 VkappaIII) were characterized. The protein Am37 had four deletions when compared with the translated germ-line gene sequence: two Ser residues following position 27 (27e, 27f) in CDR1 and two amino acids Pro-44, and Tyr-49 in FR2 were deleted. A strictly conserved salt-bridge-forming amino acid, Asp-82, was replaced by the hydrophobic residue Leu. In a comparative study of amyloidogenic and non-amyloidogenic proteins, five amino acids (Ser-10, Ala-13, Ser-65, Gln-90, and Ile-106) were found to be unique to NIG1 and several other amyloidogenic proteins. Additional substitutions also occur within these proteins. These substitutions might be significant in altering protein folding as well as in contributing to their aggregation as amyloid fibrils.

Amino Acid Sequence↗
PubMed1999

Identification and cDNA cloning of a protein abundantly expressed during apple fruit development.

A 60 kDa protein (MF-60) abundantly appearing in matured apple fruit was detected by SDS-PAGE of the soluble protein. It was partially purified through Butyl-Toyopearl and DEAE-cellulose. Its partial amino acid sequences were determined to isolate a full-length cDNA. MF-60 cDNA (mf-60) consisting of 1,825 bp containing an open reading frame of 1,524 bp and encoding a 54.2 kDa polypeptide. The deduced polypeptide of mf-60 has 81.1% identity to turgor-responsive protein 26 g from wilted garden pea shoot. Northern blot and Western blot analyses showed that the levels of the protein and the transcript of MF-60 changed in parallel through the developmental season; they were very low in young fruit at 36 DAF and 60 DAF, started to increase at 85 DAF, and then remained at a higher level from 114 DAF to 176 DAF. These results suggested that MF-60 functions are connected with fruit development but not with the fruit ripening induced by ethylene.

Amino Acid Sequence↗
PubMed1998

[Repair of complete atrioventricular septal defect with severe pulmonary hypertension--effect of re-pulmonary artery banding and analysis of lung biopsy: a case report].

We report a case complete atrioventricular defect with severe pulmonary hypertension. The patient was a girl aged 2 years and 6 months with Down's syndrome who had undergone pulmonary artery banding (PAB) 2 years previously. Postoperative catheterization after PAB showed severe pulmonary hypertension. Pulmonary resistance values were 9.3 and 7.3 units at 1 year and 5 months and 1 year and 9 months respectively. We performed re-PAB and lung biopsy when the patient was 2 years and 6 months old. The biopsy specimen at re-PAB classified as Heath-Edwards grade 3 and had an IPVD score of 1.7, indicating tolerance to radical operation. Six months after re-PAB, pulmonary vascular resistance decreased a level at which radical operation could be performed safely. Radical operation was performed 1 year and 4 months after re-PAB. The post operative course was uneventful, and pulmonary hypertensive crisis did not occur. The lung biopsy at the final operation was classified as Heath-Edwards grade 3, had an IPVD score of 1.1, and showed improvement when compared with the pathological findings at re-PAB.

Biopsy↗
PubMed1998

Surgical indication for congenital heart disease with extremely thickened media of small pulmonary arteries.

BACKGROUND: Nineteen patients (mean age, 7.6 months) with a percent wall thickness of more than 33% in the small pulmonary arteries were found to have extremely thickened media. Based on our findings, a criterion of operative indication is proposed. METHODS: The percentage of extremely thickened media of small pulmonary arteries for all pulmonary arteries was determined on microscopic lung sections and was introduced as an index for operative indication. RESULTS: Operative repair was performed in 16 patients: 9 died intraoperatively and 7 survived more than 12 months. In 4 of 5 patients that had pulmonary artery banding, medial hypertrophy remained despite pulmonary artery banding. Operative repair also had no positive effect. In operative and late deaths and in survivors without a decrease of pulmonary arterial pressure, the percentage of extremely thickened media of small pulmonary arteries was shown to be more than 10%, whereas in 5 survivors and 1 operative death with a significant postoperative decrease of pulmonary arterial pressure, the value was less than 7%. CONCLUSIONS: If a patient has less than 7% of small pulmonary arteries with extremely thickened media, operative repair is likely to be effective. When the value is higher than 10%, not only operative repair but also pulmonary artery banding cannot be recommended because of ineffectiveness and hazard.

Blood Pressure↗
PubMed1998

Inoperable pulmonary vascular disease in infants with congenital heart disease.

BACKGROUND: Among 120 infants less than 12 months of age who had lung biopsy and autopsy, 20 were inoperable because of severe irreversible pulmonary vascular disease. METHODS: The infants were classified into three groups. Group 1 comprised 6 patients who showed complete obstruction of the small pulmonary arterial lumen and atrophy of the peripheral arterial media and who were considered to have absolute operative contraindications. Group 2 comprised 6 patients who had no pathologic findings of absolute operative contraindication and had an index of pulmonary vascular disease of more than 2.2. They were isolated as having advanced plexogenic pulmonary arteriopathy. Group 3 comprised 8 patients who had extremely thickened media of small pulmonary arteries, with abnormally thickened media extending into the small peripheral arteries characterized by extremely narrow lumina and medial thickness exceeding luminal diameter. RESULTS: Six of the 9 patients in whom operative repair was abandoned on the basis of preoperative or intraoperative lung biopsy are still alive. Of the 11 patients who underwent operation without biopsy, none survived. CONCLUSIONS: Preoperative or intraoperative lung biopsy and assessment of arteriopathy based on the above criteria are recommended in all patients in whom fatal pulmonary vascular disease is suspected.

Atrophy↗