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Biomedical subjects

A Yamaguchi

Publications and source records attributed to A Yamaguchi.

At least 325 records · Page 18Linked to original sources
PubMed1995

Age-related reduction in bone matrix protein mRNA expression in rat bone tissues: application of histomorphometry to in situ hybridization.

Age-related changes in the biological activity of osteoblastic cells have been studied extensively using histomorphometry, especially in relation to osteoporosis. Nevertheless, the changes occurring in the biological activity of individual osteoblastic cells are not sufficiently clarified by this technique. In the present study, age-related changes in the expression of bone matrix protein mRNAs in individual osteoblastic cells were analyzed in vivo by in situ hybridization using undecalcified bone sections. In the femurs of 8-week-old male rats, strong expression of type I collagen and osteocalcin mRNAs was detected in cuboidal osteoblasts on the bone formation surface. Osteopontin mRNA was detected in some of the mononuclear cells and osteoclasts on the bone resorption surface, and also in osteocytes. In the femurs of 60-week-old and 100-week-old male rats, expression of these bone matrix protein mRNAs was markedly decreased. Histomorphometrical analysis of 8-week-old and 60-week-old rats indicated that both the activity and number of osteoblasts expressing type I collagen mRNA, as well as the number of osteoclasts, were reduced in these tissues in older animals. These results indicate age-related reductions in both biological activity and numbers of osteoblasts.

Aging↗
PubMed1995

Effect of sevoflurane on the vascular reactivity of rabbit mesenteric artery.

Sevoflurane is well known to cause depression of cardiovascular function, but detailed information on its actions on the contractility and reactivity of blood vessels is lacking. We have assessed therefore the direct effect of this anaesthetic on the functional reactivity of isolated rabbit mesenteric artery ring preparations. We found that contractions of endothelium intact rings induced by noradrenaline and phenylephrine were significantly attenuated by 4% sevoflurane; the observation that the maximal tension generation decreased without a significant reduction in pD2 is consistent with the view that receptor dysfunction was not involved. The effect of sevoflurane was not affected by NG-monomethyl-L-arginine. Sevoflurane 4% also produced attenuation of noradrenaline-induced contractions of endothelium denuded ring preparations. The contractions of endothelium denuded ring preparations produced by noradrenaline in Ca(2+)-free media in the presence of K+ were not affected by 4% sevoflurane, but sevoflurane depressed external Ca(2+)-dependent contractions. When vasodilators (acetylcholine and nitroglycerin) were added to the bathing media in the presence of 2% sevoflurane, the endothelium-dependent relaxation produced by acetylcholine, but not the endothelium-independent relaxation produced by nitroglycerin, was attenuated; superoxide dismutase inhibited the effect of sevoflurane on endothelium-dependent relaxation. These results are consistent with the view that sevoflurane inhibits alpha adrenoceptor-mediated contractions of isolated rabbit mesenteric artery ring preparations; this effect may be caused by reduced Ca2+ influx, as estimated from the effect on external Ca(2+)-dependent contractions, but is unlikely to be caused by reduced Ca2+ release from the sarcoplasmic reticulum of vascular smooth muscle, as estimated from noradrenaline-induced contractions in Ca(2+)-free bathing media.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1995

Expression of CD44 variant exons 8-10 in colorectal cancer and its relationship to metastasis.

Splice variants of CD44 are overexpressed in human lung, breast, and colon carcinoma cell lines. This study was conducted to clarify the association between the expression of CD44 variant exons 8-10 and metastatic potential in human colorectal cancer. We found that the expression of a CD44 splice variant containing exons v8-10 was increased in all of 60 colorectal cancer specimens examined compared with matched normal colerectal mucosa, as determined by Northern blotting. Expression of CD44 variant exons 8-10 did not significantly correlate with histological type, depth of tumor invasion, lymphatic invasion, venous invasion, or lymph node metastasis. However, the level of CD44 variant exon 8-10 expression was significantly higher in carcinomas associated with liver metastasis than in those without liver metastasis. In addition, expression of CD44 variant exons 8-10 in the liver metastases was more intense than that in the primary colorectal cancers. These findings indicated that this domain of the CD44 glycoprotein encoded by exons v8-10 may play an important role in tumor hematogenous metastasis of human colorectal cancer.

Blotting, Northern↗
PubMed1995

Expression of CD44 variant exons 8-10 in gastric cancer.

The expression of CD44 variant containing variant exons 8-10 product (CD44v8-10) was studied by western blot analysis and immunohistochemistry in gastric cancers using a monoclonal antibody, 44-1V. On western blots, a single band of 130 kD was recognized in stomach cancer cell lines. CD44v8-10 expression, with reactivity localized in the cell membrane, was found in 65 (33.5%) of the 194 advanced gastric cancers. There was no correlation between CD44v8-10 immunoreactivity and serosal, lymphatic, or lymph node invasion. However, there was significant correlation with CD44v8-10 immunoreactivity and venous invasion. CD44v8-10-positive cancers were more frequently associated with hematogenous metastasis than those which were immunonegative. There was an inverse association between CD44v8-10 immunoreactivity and peritoneal dissemination, especially in diffuse type adenocarcinomas. These observations indicate that CD44v8-10 may play a role in the metastasis of gastric cancer.

Adenocarcinoma↗
PubMed1995

Evaluation of the antithrombogenicity of a new microdomain structured copolymer.

A new antithrombogenic material was studied, fluorine-acryl-styrene-urethane-silicone (FASUS) copolymer, the theoretical basis of which attributed to its hydrophilic and hydrophobic microdomain structure. In this series of experiments, the blood compatibility of this copolymer was evaluated in vitro and ex vivo. For the in vitro evaluation, a whole blood clotting test and the microsphere column test were performed. For the ex vivo evaluation, two series of shunt tests in rabbits were performed, one was the arterioartery (A-A) shunt model, and the other was the arteriovenous (A-V) shunt model. The antithrombogenicity was assessed by measuring the shunt obstructive time in the A-A shunt experiment. The A-V shunt experiment was assessed by measuring the circulating platelet counts, platelet aggregability, activated partial thromboplastin time (APTT), and prothrombin time (PT). In the whole blood clotting test, FASUS revealed the significantly longer blood clotting time than that of the control glass tubings (19.7 +/- 1.0 versus 6.5 +/- 0.7 min, p < 0.001). In the microsphere column test, the coated group had a 30% reduction of the platelet number in the eluted blood in contrast with a marked decrease of 70% in the control group (p < 0.05). In the ex vivo A-A shunt experiment, the occlusion time for the FASUS-coated group was significantly longer than that of the control (109.7 +/- 17.3 versus 3.0 +/- 0.4 min, p < 0.05). The A-V shunt experiment showed that the FASUS copolymer suppressed the decrease in platelet counts and tended to improve prolonged APTT compared with that of the control. Clinically, in 25 patients, we placed coated FASUS copolymer into the cannulas for use in percutaneous cardiopulmonary support (PCPS) procedures. There was no evidence of thrombus on the blood contacting surface and no thromboembolism in major organs clinically or upon postmortem examination. In summary, this new copolymer may be effective in preventing thrombus formation in vitro, ex vivo, and in clinical situations.

Aged↗
PubMed1995

A novel glycylcycline, 9-(N,N-dimethylglycylamido)-6-demethyl-6-deoxytetracycline, is neither transported nor recognized by the transposon Tn10-encoded metal-tetracycline/H+ antiporter.

A novel tetracycline derivative, DMG-DMDOT [9-(N,N-dimethylglycylamido)-6-demethyl-6-deoxytetracycline] , is one of the glycylcyclines which have a broad antibacterial spectrum, including many tetracyclineresistant bacteria (R.T. Testa, P.J. Petersen, N.V. Jacobus, P.-E. Sum, V.J. Lee, and F.P. Tally, Antimicrob. Agents Chemother. 37:2270-2277, 1993). The mechanism by which DMG-DMDOT overcomes efflux-based tetracycline resistance was investigated. Tetracycline-resistant Escherichia coli cells carrying an R plasmid encoding the tet(B) gene, which encodes the typical tetracycline efflux pump [TetA(B)] of gram-negative bacteria, were as susceptible to DMG-DMDOT as was the tetracycline-susceptible host. When mid-log-phase cells carrying the tet(B) gene were incubated with a subbactericidal concentration of DMG-DMDOT (0.5 micrograms/ml) for 2 h, a significant amount of the TetA(B) protein was detected in the cell membrane by Western blotting (immunoblotting) with an anti-carboxyl-terminal antibody, similar to the case in which tetracycline was used as the inducer, indicating that the tet repressor, TetR, can recognize DMG-DMDOT as an efficient inducer. Everted membrane vesicles prepared from cells producing the TetA(B) protein showed absolutely no transport activity for DMG-DMDOT. Furthermore, the presence of excess DMG-DMDOT had no effect on the tetracycline transport activity of the everted vesicles, indicating that DMG-DMDOT is not recognized as a substrate by the TetA(B) protein.

Anti-Bacterial Agents↗
PubMed1995

Percutaneous intracavitary antifungals for a patient with pulmonary aspergilloma; with a special reference to in vivo efficacies and in vitro susceptibility results.

A 61-year-old man with pulmonary aspergilloma received two antifungals intracavitarily. Although clinical, serological and roentgenographic improvement were observed with fluconazole therapy, bronchial secretions continuously yielded Aspergillus fumigatus. When fluconazole was switched to amphotericin B, the pathogen was eradicated immediately. The minimal inhibitory concentrations (MICs) of the isolate were 400 micrograms/ml for fluconazole, and 0.2 microgram/ml for amphotericin B. Although the discrepancy between in vitro and in vivo efficacy of antifungals has been argued, it was suggested the drug of choice should be selected on the basis of the MIC results at least in the intracavitary antifungal therapy for pulmonary aspergilloma.

Administration, Cutaneous↗
PubMed1995

Microgravity generated by space flight has little effect on the growth and development of chick embryonic bone.

Seven days' space flight of fertilized chicken eggs pre- incubated for 7 and 10 days on earth caused no differences in the morphology of osteoblasts, osteoclasts, and osteocytes of humerus and tibia from those of control embryos. Bone-resorbing and -forming activities of the femur were not different between control and flight groups. As a consequence, calcium and phosphorus contents of the femora between control and flight groups were not changed. Alkaline phosphatase activity of 3 different regions (resting cartilage, growth cartilage, and cortical bone) of tibia showed no significant difference between control and flight groups. No significant difference of gene expressions of hepatocyte growth factor and receptors of fibroblast growth factor was observed in perichondrium, trabecula, and skeletal muscles and tendons of hind limbs between control and flight groups. Unlike the results of previous space flight experiments in which young growing mammals were used, these morphological and biochemical results indicate that microgravity has little effect on bone metabolism of the chick embryo.

Actins↗
PubMed1995

[A study of hierarchical structure in personality traits: asymmetry judgments in category breadth and class inclusion].

Many personality theorists postulate a hierarchical structure in trait words. However, most evidences are indirect, mainly because the theorists rely on factor-analytic methods. Assuming a global structure, the factor approach is not necessarily adequate to investigate concrete relationship among trait words. In this study, we used two direct measures to study the hierarchical structure: direct comparison of breadth and asymmetry class-inclusion judgment on trait concepts. Results of three experiments in general confirmed robustness of the hierarchical structure in the domain of personality traits. Traits were organized in the structure at several different levels of abstractness. But the structure was fuzzy in nature, unlike the taxonomy in biology. It was also found that inter-relations among traits could vary considerably from individual to individual. Cognitive complexity may be one of the variables that explain such an individual difference.

Adult↗
PubMed1995

[A case of coronary artery bypass grafting using arterial grafts in a patient with Buerger's disease].

A 50-year-old male with Buerger's disease underwent coronary artery bypass grafting (CABG) using left and right internal thoracic arteries (LITA and RITA). In our case, his saphenous veins could not be used because of migrating thrombophlebitis, and we could not use right gastroepiproic artery because he had undergone gastrectomy for gastroduodenal ulcer. He underwent CABG with LITA-left anterior descending artery and free RITA-right coronary artery. Postoperative coronary angiogram showed good patency of both grafts, and his postoperative course has been uneventful for 42 months. To our knowledge, there is no report of CABG in a patient with Buerger's disease, but we think the use of arterial grafts is useful in such cases.

Coronary Artery Bypass↗
PubMed1995

[Successful surgical treatment of mitral regurgitation associated with anti-phospholipid syndrome and systemic lupus erythematosus].

A 39-year-old woman with the diagnosis of mitral regurgitation was admitted to our hospital for surgical treatment. Cerebral thromboembolism and spontaneous abortion had been repeated in her past history. She was suffered from chronic renal failure associated with systemic lupus erythematosus (SLE) and anti-phospholipid syndrome (APS). An operative procedure was recommended because of the progressive heart failure due to mitral regurgitation. For renal failure, continuous ambulatory peritoneal dialysis (CAPD) was introduced at one month before operation. As the operative procedure, valve replacement using Carpentier-Edwards bioprosthesis (27 mm) was done rather than valve reconstruction, because chordal rupture of posterior leaflet and severe hypertrophy of both leaflets were recognized. During operation, uncontrollable bleeding was not observed. However, platelet transfusion was needed. We use warfarin and antiplatelet agents jointly as postoperative anticoagulant therapy. Thromboembolic episodes have not been observed 4 years postoperatively. Relationship between SLE with APS and cardiac valvular lesions has been focused. The present case was considered to be the interesting case which various devices were necessary to operative management including chronic renal failure, cardiopulmonary bypass, selection of prosthetic heart valve, and postoperative anticoagulant therapy for preventing thrombus formation.

Adult↗
PubMed1995

[Re-replacement of Starr-Edwards mitral valve (model 6320) for prosthetic valve endocarditis 22 years after replacement].

The patient was a 43-year-old woman who had undergone mitral valve replacement with Starr-Edwards ball valve (model 6320) 22 years ago. Perivalvular mitral leakage due to prosthetic valve endocarditis and tricuspid regurgitation were found. She underwent re-replacement of the mitral valve. The operative findings revealed almost intact valvular function of the ball valve. As far as we know, 22 years is the longest follow-up for the Starr-Edwards ball valve which has maintained normal function.

Adult↗
PubMed1995

[Intermediate to late results of aortic or mitral valvuloplasty by rasping procedure].

We have proposed Rasping procedure as one of the methods of aortic valvuloplasty (A-Rasping) and defined as debridement of the thickened surface of the rheumato-degenerative aortic valve using an electric rasper since 1986. Furthermore, we have extended this technique to mitral valvuloplasty (M-Rasping). The purpose of this study is to evaluate intermediate to late results of valvuloplasty by Rasping procedure. From 1986 to 1994, this method was carried out on 14 patients with mild-to-moderate aortic valve disease in severe mitral valve disease or coronary artery disease, and on 6 patients with mitral stenosis. In A-Rasping group, aortic regurgitation was found in 10 patients and aortic stenosis was found in 4 patients. The degree of regurgitation, the transvalvular pressure gradient, and the pre- and postoperative cardiac function in both group were investigated chronologically by echocardiography. In this series of patients, no hospital mortally including operative death was observed. Furthermore, reoperation for repaired aortic or mital valve was not required. In A-Rasping group, 2 late deaths (14.2%) occurred at 1 year and 4 years after operation. Cause of 2 late deaths was prosthetic valve endocarditis in mitral position. In A-Rasping group, at 1 year after operation, regurgitation was reduced to degree I or less in all patients. However, at the 3rd postoperative year, regurgitation increased to degree II in 2 patients. As compared with the preoperative values, the transvalvular pressure gradient significantly decreased in 4 patients (29.5 +/- 7.6 mmHg vs 12.5 +/- 5.0 mmHg, p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Successful resection and repair of the superior vena cava and right atrium in a patient with invasive thymoma].

A 45-year-old female, who suffered from Superior Vena Cava (SVC) syndrome, was diagnosed as invasive thymoma by means of trans-sternal aspiration cytology (TSAC). After preoperative radiotherapy and two courses of neoadjuvant chemotherapy, she underwent radical tumor resection combined with partial resection of both SVC and the right atrium followed by pericardial patch repair under the cardiopulmonary bypass. Complete resection is the most important procedure for the therapy of invasive thymoma, even if the tumor is in advanced stage invading to large vessels such as SVC. As far as our knowledges are concerned, complete resection of invasive thymoma combined with partial resection of the right atrium is very rare. Our case shows that partial resection of the right atrium is not risky operative procedure, if the invaded lesion of the right atrial wall is localized at the antero-lateral side to which the sinus node and the conducting system is not close. And we chose pericardial patch repair for the large defect of SVC. This patch repair was good method in this case because the blood flow through the Azygos vein was well maintained. We would also like to emphasize that TSAC is useful diagnostic procedure for the mediastinal mass lesion to which transcutaneous aspiration using the ultrasound or CT scan as a guide is impossible.

Female↗
PubMed1995

[The role of CD44 adhesion molecules].

CD44 is a transmembrane glycoprotein involved in the interaction between cells and extracellular matrix. CD44 is ubiquitously expressed on cells, and has been thought to be a cell adhesion molecule with proposed functions in extracellular matrix binding, cell migration and lymphocyte homing. In 1991, Stamenkovic et al. showed the existence of two forms of CD44: a hematopoietic (standard) and an epithelial form which was highly expressed by carcinomas. The alternative splicing of 10 variant exons encoding the membrane proximal portion of the external domain of CD44, in particular, results in many variant isoforms. These may play a critical role in malignant behavior and in determining organ specificity in metastasis.

Humans↗
PubMed1995

[A case of duodenal duplication and a review of reported cases].

We report a case of duodenal duplication and review of literatures on 43 cases reported in Japan including ours. A 34-year-old female who was admitted with chief complaints of epigastric pain and hematoemesis. An endoscopic examination and a hypotonic duodenography revealed a protruding tumor with bleeding ulcer. Wedge resection of the duodenum, including the lesion, was performed. A diagnosis of duodenal duplication was made by histopathological examination.

Adult↗