Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 487 records · Page 27Linked to original sources

PubMed1998

[Successful staged repair of corrected transposition of great arteries and mitral atresia associated with double aortic arch].

We report a rare case of corrected transposition of great arteries and mitral atresia associated with double aoric arch. The patient showed polypnea and cyanosis soon after birth. She underwent balloon atrioseptostomy at the age of 18 days and pulmonary artery banding (PAB) at 24 days. But she showed severe persistent stridor after PAB. Esophagography and left counter-current aortography revealed double aortic arch. At the age of 49 days, division of the left lesser arch and ligation of patent ductus arteriosus were performed through left lateral thoracotomy. Stridor disappeared completely following operation. She underwent total cavopulmonary connection using a 18 mm Gore-Tex graft as intraatrial conduit concomitant with pacemaker implantation at the age of 8 years. Postoperative course was uneventful. To our knowledge, this is the first successful case report of surgical correction of corrected transposition of great arteries and mitral atresia associated with double aoric arch.

Aorta, Thoracic↗

PubMed1998

Expression of the cyclin-dependent kinase inhibitor, p21Waf-1/Cip-1/Sdi-1, in human vascular smooth muscle cells in the proliferating state.

Excess proliferation of vascular smooth muscle cells (SMC) is an important aspect of atherogenesis. Cell-cycle regulatory proteins such as cyclin and cyclin-dependent kinases are vital for cell-cycle progression. To understand the role of the cyclin-dependent kinase inhibitor, p21Waf-1/Cip-1/Sdi-1 (p21Waf-1), on human atherogenesis, we tested p21Waf-1 expression in human atherosclerotic lesions and cultured SMC. Immunohistochemical staining revealed that SMC in neointimal lesions expressed p21Waf-1. No evidence of the p53 protein could be detected. By Western blotting, cultured SMC obtained from a neonate revealed that a higher level of p21Waf-1 expression correlated with a higher expression of proliferating cell nuclear antigen and a lower expression of the contractile protein than that observed in cells obtained from aged donors. When the phenotypes of SMC were changed by modification of serum concentration and cell densities, p21Waf- expression was maximal in serum-stimulated SMC at low cell densities despite the low expression of p53. Furthermore, serum stimulation transiently increased the p21Waf-1 expression of quiescent SMC, which was synchronized with the transition from the G0/G1 to the S phase as well as with cyclin D1 expression. These results may suggest that the negative regulator of cell-cycle progression also plays a role in regulating the appropriate cell-cycle progression in SMC. Growth stimuli may induce both growth-promoting and growth-inhibitory factors in SMC. The balance between these two opposing factors may play an important role in the determination of cell-cycle progression.

Arteriosclerosis↗

PubMed1998

Mechanisms responsible for resistance of sublines derived from leukemia cell lines to an antitumor agent 9-beta-D-arabinofuranosyl-2-fluoroadenine.

An agent 9-beta-D-arabinofuranosyl-2-fluoroadenine (2-F-Ara-A) is a main metabolite of fludarabine, a fluorinated purine analogue with antitumor activity in lymphoproliferative malignancies. In this study, the mechanism responsible for the resistance of cancer cells to fludarabine was examined using the 2-F-Ara-A-resistant sublines JOK-1/F-Ara-A and L1210/F-Ara-A from a human hairy leukemic cell line (JOK-1) and a mouse leukemic cell line (L1210) respectively, which were established by continuous treatment of the parental cell lines with 2-F-AraA. JOK-1/F-Ara-A and L1210/F-Ara-A cells were more than 55 and 29 times more resistant to 2-F-Ara-A than were their parent cell lines, and showed a high cross-resistance to 1-beta-D-arabinofuranosylcytosine but not to doxorubicin or vincristine. These resistant sublines intracellularly accumulated almost the same amount of 2-F-Ara-A as did their parent cell lines. However, the amount of 2-F-Ara-ATP, a cytotoxic metabolite of 2-F-Ara-A, decreased by 2.6% (JOK-1/F-Ara-A C3), 6% (L1210/F-Ara-A C1) and 3.7% (L1210/F-Ara-A C7) relative to the levels in the parent cell lines. Enzymatically, these resistant cells hardly activated deoxycytidine (dCyd) and 2-F-Ara-A. In addition, the abilities to phosphorylate deoxyadenosine and deoxyguanosine were also decreased in the resistant cells in comparison with the parent cells. These findings suggest that the deficiency in activity of dCyd kinase may contribute to the resistance of 2-F-Ara-A.

Animals↗

PubMed1998

Trapidil effects on intimal thickening and mRNA levels for platelet-derived growth factor A in human saphenous vein smooth muscle cells.

BACKGROUND: Platelet-derived growth factor (PDGF) A chain, basic fibroblast growth factor (bFGF), and tissue-type plasminogen activator (tPA) from smooth muscle cells (SMCs) have been postulated to initiate SMC proliferation and migration in the process of intimal thickening. OBJECTIVE: In this study we tested whether trapidil, which is reported to reduce intimal thickening, would suppress mRNA increases for all or only some of these genes in human SMC. METHODS: Cultured human saphenous vein SMCs made quiescent by 72-hour incubation in 0.5% serum were stimulated with 3U/mL alpha-thrombin +/- trapidil. Changes in mRNA transcript levels were analyzed by Northern blot. RESULTS: Trapidil decreased thrombin-induced mRNA levels for bFGF and appeared to decrease mRNA for PDGF-A chain, but not for tPA. CONCLUSION: These results suggest that trapidil may reduce intimal thickening at least partly via the suppression of increased bFGF and PDGF-A chain mRNA levels in vascular SMCs.

Autoradiography↗

PubMed1998

Growth of the subclavian artery and the anastomosis in Blalock-Taussig shunt: absorbable versus nonabsorbable suture.

BACKGROUND: We evaluated the growth of Blalock-Taussig shunts placed with absorbable suture by cineangiographic findings and long-term results and compared them with those in an earlier group of patients in whom we used nonabsorbable suture. METHODS: Eighty-one patients had postoperative cineangiography 1 year or more after a Blalock-Taussig shunt procedure. From September 1985 to December 1994, 40 patients (group I) underwent a Blalock-Taussig shunt procedure with the use of absorbable polydioxanone suture, and from January 1980 to August 1989, 41 (group II) underwent the same operation with nonabsorbable polypropylene suture. Cineangiograms were reviewed to assess shunt patency and growth of the subclavian arteries and the subclavian artery-pulmonary artery anastomoses. RESULTS: At the Blalock-Taussig shunt operation, mean outer diameters of the subclavian artery and the anastomosis in group I were 3.8 +/- 0.1 mm and 4.1 +/- 0.1 mm, respectively and 3.9 +/- 0.1 mm and 4.0 +/- 0.1 mm in group II. The mean inner diameters of the subclavian artery and the anastomosis measured in postoperative cineangiograms were 7.9 +/- 0.5 mm and 4.6 +/- 0.2 mm, respectively in group I and 6.6 +/- 0.4 mm and 3.1 +/- 0.2 mm in group II. The diameters of both the subclavian artery (p < 0.05) and the anastomosis (p < 0.001) were significantly greater in group I than in group II. Five years after operation, 71.1% +/- 7.4% of patients in group I and 54.8% +/- 8.0% in group II had good palliation. CONCLUSIONS: The use of absorbable polydioxanone suture has an advantage in terms of growth of the diameters of the subclavian artery and the anastomosis in a Blalock-Taussig shunt and may improve the long-term results after this shunt operation in infancy.

Absorption↗

PubMed1998

Systemic atherosclerosis in dogs: histopathological and immunohistochemical studies of atherosclerotic lesions.

Histopathological and immunohistochemical studies were carried out on five cases of canine systemic atherosclerosis. The five animals were male, and showed hypercholesterolaemia and hypertriglyceridaemia on biochemical analysis of plasma. Histopathologically, atherosclerotic lesions were seen in the aorta and muscular arteries in many organs, including the heart, spleen, kidneys, lungs, pancreas, alimentary tract, urogenital organs, eyes, prostate and urinary bladder. The lesions were characterized by the deposition of lipids and infiltration of lipid-laden foamy cells in the tunica intima and tunica media, sometimes forming fibrofatty plaques, containing abundant sudanophilic material, cholesterol clefts and mineralized material. The lesions started in the tunica intima and extended to the tunica media and tunica adventitia. Immunohistochemical examination with canine apolipoprotein B-100 (CApoB-100) antibody identified the lipids containing low density lipoprotein. Immunoreactivity to CApoB-100 antibody was recognized in the tunica intima, lipid-laden foamy cell cytoplasm and smooth muscle cells in the tunica media, and fibrofatty plaque. These histopathological and immunohistochemical features were similar to those of human atherosclerotic lesions.

Age Factors↗

PubMed1998

Endoscopic sphincterotomy and laparoscopic cholecystectomy in an infant with cholecysto-choledocholithiasis.

Laparoscopic cholecystectomy (LC) and endoscopic sphincterotomy (EST) are widely accepted procedures for cholecysto-choledocholithiasis in adults. However, their use in infants has not been reported. An 8-month-old girl presented with high fever and obstructive jaundice. Ultrasound scan showed acute cholecystitis with stones in the bile duct. After 2-week-long antibiotic therapy the acute cholecystitis and hepatic impairment resolved. An endoscopic retrograde cholangiopancreatography (ERCP) confirmed choledocholithiasis and cholecystolithiasis. Risk factors for the development of biliary calculi were not detected. One month after the restoration of her liver function, she underwent EST using a side-viewing endoscope with a small sphincterotome. A common bile duct stone was extracted using a basket catheter. LC was then carried out. The time interval between the EST and LC was 34 days. No complications have been noted for 6 months.

Cholangiopancreatography, Endoscopic Retrograde↗

PubMed1998

Slide tracheoplasty: a case report of successful concomitant reconstruction of extensive congenital tracheal stenosis and pulmonary artery sling.

An 8-month-old infant presented with an extensive congenital tracheal stenosis with an aberrant left pulmonary artery. The patient was treated successfully by relocation of the left pulmonary artery and tracheal reconstruction with slide tracheoplasty. This patient is the first survivor cited in the literature after concomitant repair using slide tracheoplasty.

Abnormalities, Multiple↗

PubMed1998