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Biomedical subjects

S Sekine

Publications and source records attributed to S Sekine.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Long-term results of patients undergone surgical repair for acute type A dissection].

We evaluated the long-term results of 28 operative survivors who underwent surgical repair for acute type A dissection. Residual dissection of the thoracic aorta was found in 21 patients (75.0%) postoperatively, and 6 of them underwent reoperation with no operative death. There were 2 late death; one died in the third operation for thoracoabdominal aorta and the other died of cancer. Two of 4 patients with Marfan's syndrome required total aortic replacement ultimately. Since the elective reoperation can be performed safely, careful follow-up and management is essential for the improved survival of the patients with residual aortic dissection.

Acute Disease↗
PubMed1998

[A case of infective thoracic aortic aneurysm ruptured to the lung].

We report a successful surgical treatment of an infective thoracic aortic aneurysm ruptured to the left lung. A 63-year-old man who had been suffering from fever and cough showed twice of hemoptysis. Chest CT revealed a descending thoracic aortic aneurysm ruptured to the left lung. A semiemergent operation was performed. At operation, aneurysm of descending thoracic aorta was found adherent to the left lung. Aneurysmectomy with left pneumonectomy was carried out. The postoperative course of the patient was uneventful. Conceivably, in order to avoid massive intraoperative bleeding during division of dense adhesion and postoperative graft infection, concomitant lung resection is necessary.

Aneurysm, Ruptured↗
PubMed1998

Supraannular aortic root enlargement in patients with small aortic annulus: efficacy and safety.

BACKGROUND: To accommodate optimal sized aortic valve, our experiences with supraan-nular aortic root enlargement (SAE) in 20 patients with small aortic annulus have been described. METHODS: From June 1981 to April 1996, aortic valve replacement with a St. Jude Medical (SJM) valve had been performed in 46 patients with aortic stenosis consecutively. After August 1993, we employed SAE in patients to insert 23 mm or larger aortic prostheses (SAE group, n = 20; control group, n = 26). Patients were followed-up for a period of 1.7 to 8.3 years. RESULTS: There were no intra- or postoperative complications. The pressure gradient across the prosthesis was greater than 30 mmHg in 4 patients of the control group and in 1 patient of the SAE group. Only in nineteen patients (73%) of the control group, 23 mm or larger sized valves could be implanted by a conventional technique. By contrast, with SAE, 23 mm or larger sized SJM prostheses were possible to implant in 19 out of 20 patients (95%). CONCLUSION: To avoid valve-patient mismatch, SAE of aortic root is safe and effective.

Aortic Valve↗
PubMed1997

Expression cloning of cDNA encoding a human beta-1,3-N-acetylglucosaminyltransferase that is essential for poly-N-acetyllactosamine synthesis.

The structure and biosynthesis of poly-N-acetyllactosamine display a dramatic change during development and oncogenesis. Poly-N-acetyllactosamines are also modified by various carbohydrate residues, forming functional oligosaccharides such as sialyl Lex. Herein we describe the isolation and functional expression of a cDNA encoding beta-1,3-N-acetylglucosaminyltransferase (iGnT), an enzyme that is essential for the formation of poly-N-acetyllactosamine. For this expression cloning, Burkitt lymphoma Namalwa KJM-1 cells were transfected with cDNA libraries derived from human melanoma and colon carcinoma cells. Transfected Namalwa cells overexpressing the i antigen were continuously selected by fluorescence-activated cell sorting because introduced plasmids containing Epstein-Barr virus replication origin can be continuously amplified as episomes. Sibling selection of plasmids recovered after the third consecutive sorting resulted in a cDNA clone that directs the increased expression of i antigen on the cell surface. The deduced amino acid sequence indicates that this protein has a type II membrane protein topology found in almost all mammalian glycosyltransferases cloned to date. iGnT, however, differs in having the longest transmembrane domain among glycosyltransferases cloned so far. The iGnT transcript is highly expressed in fetal brain and kidney and adult brain but expressed ubiquitously in various adult tissues. The expression of the presumed catalytic domain as a fusion protein with the IgG binding domain of protein A enabled us to demonstrate that the cDNA encodes iGnT, the enzyme responsible for the formation of GlcNAcbeta1 --> 3Galbeta1 --> 4GlcNAc --> R structure and poly-N-acetyllactosamine extension.

Adult↗
PubMed1997

Eradication of Helicobacter pylori in patients with end-stage renal disease under dialysis treatment.

The efficacy and safety of combination therapy with amoxicillin, lansoprazole, and plaunotol for the eradication of Helicobacter pylori in patients on dialysis were evaluated. The study subjects comprised 15 dialysis patients in whom H pylori had been found in the gastric mucosa. The patients were given 500 mg amoxicillin once a day for 3 weeks, 30 mg lansoprazole once a day for 8 weeks, and 80 mg plaunotol three times a day for 24 weeks. Endoscopy was performed on entry and at 4 and 24 weeks after cessation of amoxicillin. The concentrations of serum gastrin and gastric juice ammonia also were measured. Fourteen patients completed the treatment protocol, one having dropped out because of nausea and diarrhea. H pylori was eradicated in 11 of the 14 patients 4 weeks after the end of amoxicillin therapy (eradication rate, 78.6%). All but one patient was free of H pylori 24 weeks after the amoxicillin was discontinued. Patients who became negative for H pylori had significantly decreased serum gastrin and gastric juice ammonia concentrations. Our findings indicate that a combination of amoxicillin, lansoprazole, and plaunotol can be used to eradicate H pylori in patients on dialysis.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1997

Human cDNA encoding a novel TGF-beta superfamily protein highly expressed in placenta.

Recently, we developed a simple method for detecting a secretory signal sequence encoded by a cDNA fragment. In this study, we used this method to select cDNA clones encoding secretory proteins from a human full-length cDNA library. Full-sequencing analysis of the candidate clones revealed that one clone encoded a novel TGF-beta superfamily protein. The clone encodes a protein of 308 amino acids of which the C-terminal region shows a characteristic feature of TGF-beta superfamily proteins: seven conserved cysteine residues at the C-terminal preceded by a putative processing site composed of a basic amino acid repeat. The corresponding transcripts are highly expressed in the placenta, so the novel protein may play an important role in reproduction.

Amino Acid Sequence↗
PubMed1997

Is the dog a useful model for accelerated calcification study of cardiovascular bioprostheses?

Chitosan posttreatment has been shown to be effective in prevention of calcification of the glutaraldehyde treated bovine pericardium when implanted subdermally in rats for 12 weeks. The efficacy of chitosan posttreatment in complete calcium mitigation of the glutaraldehyde treated porcine aortic valves implanted in the right side of the heart in dogs was well-documented in our previous study. In this study, an attempt has been made to evaluate the merit of the chitosan posttreatment in prevention of calcification of the glutaraldehyde (GA) treated porcine aortic valved conduits in the systemic circulation in dogs for a period of 5 months. Eleven mongrel dogs underwent left thoracotomy. Porcine aortic valved conduits treated with 0.625% GA (n = 5) and GA-chitosan (n = 6) were implanted in the descending thoracic aortas of the dogs for 5 months. Gross histological observations showed no calcification in either the 0.625% GA treated or in the GA-chitosan treated valved conduits at 5 months. This was confirmed by results of quantitative analyses for calcium in each explant. There was no significant difference in calcium content between the GA only (Ca, 0.43 +/- 0.26 mg/g) and GA-chitosan treated (Ca, 0.51 +/- 0.19 mg/g; p = 0.5959) valved conduits. This study suggests that the dog is not a suitable model for evaluating the efficacy of a calcium mitigating agent in bioprostheses implanted in systemic circulation.

Animals↗
PubMed1997

Mitral regurgitation caused by mitral paraannular cyst.

A case of mitral regurgitation (MR) caused by mitral paraannular cyst is reported. A 37-year-old woman on maintenance hemodialysis was admitted to Akita University Hospital because of congestive heart failure. Echocardiography revealed mitral paraannular cyst, which caused coaptation failure of the mitral leaflets and significant MR. She underwent decapsulation of the cyst followed by mitral valve replacement. Postoperative echocardiography showed no recurrence of the cyst three years after surgery. Although mitral annular calcification has been described as a cause of MR in patients with uremia, a report of a solitary intracardiac cyst which causes significant MR is quite rare.

Adult↗
PubMed1997

Minimum inhibitory concentration of various single agents and the effect of their combinations against Helicobacter pylori, as estimated by a fast and simple in vitro assay method.

OBJECTIVES: Fast and simple in vitro methods of accurately assaying anti-Helicobacter pylori (H. pylori) activity are needed to facilitate the selection of optimal drugs for the eradication of H. pylori. With that purpose in mind, we developed a broth microdilution technique that uses a 96-well flat-bottom microplate. METHODS: Clinical isolates of H. pylori were placed in 25-cm2 tissue culture flasks and were grown in an atmosphere of 5% CO2 in air at 37 degrees C and 100% humidity. Then they were inoculated in 96-well flat-bottom microplates. After 24 h, the bacterial growth was assessed by automatic measurement at A450 with a microplate reader. Minimum inhibitory concentrations (MICs) of 11 drugs against H. pylori and the effect of two-drug combinations were respectively evaluated by the broth microdilution technique and by calculating the fractional inhibitory concentration index according to the checkerboard titration method. RESULTS: The MICs of all drugs tested with this system roughly agreed with those of previous reports in which the agar dilution method was used. The MIC of lansoprazole, a proton pump inhibitor, was low (0.88 microg/ml) and surpassed that of metronidazole (3.15 microg/ml). The effect of the combination of macrolide antibiotics with tetracycline was favorable. The proton pump inhibitor demonstrated a strong additive effect with macrolide antibiotics and fostered the activity of ecabet sodium (mucosal protective agent). CONCLUSION: This system could estimate the MIC of individual drugs quickly and simply, and could accurately measure the efficacy of two-drug combinations in vitro.

Anti-Bacterial Agents↗
PubMed1996

Major identity determinants in the "augmented D helix" of tRNA(Glu) from Escherichia coli.

By a kinetic analysis of 59 variant transcripts of Escherichia coli tRNA(Glu) with glutamyl-tRNA synthetase (GluRS), the U11.A24 base-pair, the U13.G22..A46 base-triple, and the lack of residue 47 (delta47) were found to serve as major determinants for tRNA(Glu) identity. This is the first system for which major identity determinants are reported to be clustered in the "augmented D helix", consisting of the D stem with some neighboring residues and the variable loop. Other identity determinants are U34, U35, C36 and A37 in the anticodon loop, and G1.C72 and U2.A71 in the acceptor stem. Phosphate-group protection by GluRS from ethylnitrosourea was observed most strongly for the minor groove side of D-stem helix, indicating that GluRs tightly binds to the D stem for recognition, on the minor groove side, of the potent identity-determinant groups of the U11.A24 and U13.G22 base-pairs. A46 is not involved in direct recognition by GluRS; the U13.G22..A46 base-triple is required probably for formation of the structural features that are recognized by GluRS. In this context, the essential role of characteristic delta47 in tRNA(Glu) identity may be to maintain the U13.G22..A46 base-triple.

Anticodon↗
PubMed1996

Surgical treatment of isolated secundum atrial septal defect in patients more than 50 years old.

BACKGROUND: Arrhythmia-related thromboembolic accidents continue to occur in patients even after closure of secundum atrial septal defect. Older age is usually not a contraindication to the repair of an atrial septal defect. To assess the importance of the type of management in elderly patients with atrial septal defect our clinical experience is reviewed. METHODS: Between 1974 and 1994, 49 patients 50 years of age or older (average, 57.4 years) underwent surgical closure of secundum atrial septal defect. All patients have been followed up for 2 to 21 years (mean, 9.7 years). RESULTS: There were no operative deaths. Functional classes in most of the patients were improved after operation. There were two cerebrovascular thromboembolic accidents with one permanent neurologic dysfunction, hemiparesis, and one septal dehiscence in the early postoperative period. One patient (2%) died of renal failure 6 years after operation, late arrhythmias developed in 3 patients (6%), 3 patients had a late stroke (6%), and 1 patient was not available for follow-up. CONCLUSIONS: Long-term operative results are satisfactory and beneficial to the quality of life in elderly patients. Because there is no safe and effective nonsurgical alternative to surgical closure, atrial septal defect repair in elderly patients without severe pulmonary vascular disease should not be delayed once the diagnosis had been made.

Age Factors↗
PubMed1996

Composite graft replacement of the aortic root in patients with Marfan's syndrome.

Between October, 1979 and September 1994, 18 consecutive patients with Marfan's syndrome underwent replacement of the ascending aorta and aortic valve with a composite graft. There were 11 men and seven women; the mean age was 38.7 years. All patients had annuloaortic ectasia with significant aortic regurgitation. Ten of the 18 patients had aortic dissection. Concomitant procedures were performed in three patients. The hospital mortality rate was 17%, and two patients with concomitant procedures died early after surgery. There were three late deaths, two of which were related to late aortic complications. The actuarial 8-year survival rates in patients with and without aortic dissection were 58.3% and 77.8%, respectively. Since aortic dilatation and its complications are progressive in patients with Marfan's syndrome, improved surgical results can be obtained early in the course of the disease before cardiac disturbances and aortic dissections emerge.

Actuarial Analysis↗
PubMed1996

Cloning and expression of cDNA encoding a human ubiquitin-conjugating enzyme similar to the Drosophila bendless gene product.

cDNA encoding a novel human ubiquitin-conjugating enzyme has been cloned from an epidermoid carcinoma KB cDNA library. This clone encodes a protein of 152 amino acids with a calculated M(r) of 17,137. The amino acid sequence showed 80% identity with the Drosophila's bendless gene product (ubiquitin-conjugating enzyme E2). The corresponding transcripts are highly expressed in heart, skeletal muscle, and testis. The product expressed in Escherichia coli exhibited the ability to form a thiol ester linkage with ubiquitin in a ubiquitin-activating enzyme E1-dependent manner. These results suggest that the obtained cDNA encodes a novel human E2 which may be involved in protein degradation mainly in the muscles and testis.

Amino Acid Sequence↗
PubMed1996

[Coronary artery bypass grafting in a patient with severe coronary disease due to Kawasaki disease: a case report].

A 14-year-old girl with severe coronary artery disease due to mucocutaneous lymph node syndrome, "Kawasaki disease", admitted to our hospital. Though she had no angina on any effort in her daily life, coronary angiography (CAG) demonstrated 90% stenosis and a large aneurysm of left main trunk. Based on the CAG findings, we determined to do the coronary artery bypass grafting (CABG) to left anterior descending artery (LAD) and 1st diagonal branch (D1) to prevent the occurrance of fatal acute myocardial infarction. We attempted to use bilateral internal thoracic arteries (ITAs) at the beginning of this surgery. While LAD was grafted with left one, D1 was done with saphenous vein (SV) because of difficulty of harvesting right one. The weaning from cardiopulmonary bypass was easy and the postoperative course was of no event. A month later, CAG showed the good patency of both left ITA and SV graft.

Adolescent↗
PubMed1996

[Aortic root replacement employing Cabrol and Piehler techniques].

Between February, 1982, and September, 1994, 24 patients underwent aortic root replacement using a valve-bearing composite graft and coronary perfusion grafts. The indications for surgery were annulo-aortic ectasia in 21 patients, and aortic dissection associated with significant aortic regurgitation in 3 patients. Aortic root was reconstructed employing the techniques described by Cabrol and colleagues (Cabrol operation) in 16, and by Piehler and Pluth (Piehler operation) in 8. Two of 16 patients who underwent Cabrol operation required concomitant procedures. Four patients (25.0%) who underwent Cabrol operation had technical troubles relating to coronary reattachements (kinking and torsion of coronary grafts in 2, obstruction of left limb of coronary graft in 1, and coronary graft compression by aortic wall wrapping in 1), while one patient (12.5%) having Piehler operation had coronary graft compression by partial wrapping of aortic root. The hospital deaths occurred in 4 patients undergone Cabrol operation, with the hospital mortality rate being 16.7%. Three patients including 2 with concomitant procedures died of low cardiac output and one died of rupture of residual dissecting aneurysm of the aortic arch. No pseudoaneurysm nor anastomotic stenosis was observed in any hospital survivors. Late deaths occurred in 5 patients, in whom there was no late complication relating to coronary reconstruction. However, late obstruction of left ostial stenosis developed in one patient who underwent Piehler operation, which required coronary artery bypass. We conclude that aortic root replacement using coronary perfusion grafts provides sound coronary anastomoses without late pseudoanurysm. Coronary reattachments is facilitated by use of Piehler technique, preventing coronary graft kinking or torsion. Late coronary ostial stenosis should be considered as a possible cause of fatal myocardial infarction and sudden death, and careful follow-up is required for patients having these kinds of operation for the prevention of late cardiac events.

Adult↗
PubMed1995

A three-dimensional structure model of the complex of glutamyl-tRNA synthetase and its cognate tRNA.

A docking model of glutamyl-tRNA synthetase (GluRS) and tRNAGlu was constructed, on the basis of the distinguished similarity between the X-ray crystallographic three-dimensional structures of the N-terminal halves of the Thermus thermophilus GluRS in the free state and the Escherichia coli glutaminyl-tRNA synthetase in a complex with tRNAGln. The modeled structure is energetically favorable and is also well consistent with the results of site-directed mutagenesis studies. The model indicates that the GluRS-specific insertions 2 and 3 fit and bind to the acceptor stem and the D arm, respectively, of the cognate tRNA without affecting other contacts. In particular, insertion 3 strongly interacts with the two D-stem base pairs that are essential for the tRNA-GluRS recognition.

Anticodon↗
PubMed1995

Architectures of class-defining and specific domains of glutamyl-tRNA synthetase.

The crystal structure of a class I aminoacyl-transfer RNA synthetase, glutamyl-tRNA synthetase (GluRS) from Thermus thermophilus, was solved and refined at 2.5 A resolution. The amino-terminal half of GluRS shows a geometrical similarity with that of Escherichia coli glutaminyl-tRNA synthetase (GlnRS) of the same subclass in class I, comprising the class I-specific Rossmann fold domain and the intervening subclass-specific alpha/beta domain. These domains were found to have two GluRS-specific, secondary-structure insertions, which then participated in the specific recognition of the D and acceptor stems of tRNA(Glu) as indicated by mutagenesis analyses based on the docking properties of GluRS and tRNA. In striking contrast to the beta-barrel structure of the GlnRS carboxyl-terminal half, the GluRS carboxyl-terminal half displayed an all-alpha-helix architecture, an alpha-helix cage, and mutagenesis analyses indicated that it had a role in the anticodon recognition.

Amino Acid Sequence↗