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Biomedical subjects

A Yamaguchi

Publications and source records attributed to A Yamaguchi.

At least 433 records · Page 24Linked to original sources
PubMed1993

[Prosthetic valve endocarditis after double valve replacement].

This is a report of a patient who underwent re-AVR due to prosthetic valve endocarditis after double valve replacement (MVR, AVR). A 54-year-old female was admitted to other hospital on April 14, 1990, because of high fever, progressive anemia, and cardiomegaly. The patient was hospitalized to our department urgently with the diagnosis of prosthetic valve endocarditis. Arterial blood culture grew methicillin-resistant Staphylococcus epidermidis. Echocardiography showed a vegetation at the disc of the mechanical valve in the mitral position, but we could not find any vegetation or thrombus there at the reoperation, and the aortic mechanical valve seemed to be intact. Signs of inflammation continued to be positive after reoperation. On the 33rd hospital day, a diastolic murmur was heard, and emergency cardiac catheterization was done. Detachment of the prosthetic aortic valve and rupture of the sinus of Valsalva due to mycotic aneurysm, and the dissection of the aorta had occurred. We performed re-AVR and replacement of the ascending aorta. The patient died of multiple organ failure following drug-induced hepatic failure. It is suggestive that we missed the prosthetic aortic valve endocarditis during the reoperation. Our thoughts and introspections on the echocardiographic diagnosis of the prosthetic valve endocarditis after double valve replacement were discussed.

Aneurysm, Infected↗
PubMed1993

[Autotransplantation as optimal technique for recurrent malignant myxoma of left ventricle].

Application of autotransplantation for left ventricular recurrent malignant tumor which was considered to be originating from the posterior leaflet of mitral valve was presented. A patient was 29 year-old-female and underwent the resection of tumor. The tumor was resected en bloc with the mitral valve, and its histology was myxoma. But she was required reoperation two times because of the recurrence of the tumor unfortunately. The tumor was ultimately diagnosed as the myxofibrosarcoma with chondroid differentiation. At the time of the third surgery, the heart transplantation was thought to be only treatment for radicality. While sounding American counterparts on the possibility of the heart transplantation, her condition took a sudden turn for the worse. An autotransplantation technique was applied for the resection of the tumor emergently. As a result, it was impossible to completely resect the tumor because of severe invasion to the left ventricle, and the patient died suddenly on the 75th day after the operation due to fetal arrhythmia. Through this case, heart transplantation should be considered for such a case, but autotransplantation technique allowed to be a life-prolonging in this case. We believe that this technique which will be obtained the excellent operative field could be used for repair of complex cardiac anomalies and rupture of left ventricle and so on.

Adult↗
PubMed1993

[Basic study of CA549, a new tumor marker for breast cancer, and evaluation of its clinical usefulness].

We performed basic and clinical studies of IRMA kits for serum CA549 antigen and examined the immunological correlation between CA549 and CA15-3 antigens. Satisfactory results were obtained in the basic studies of CA549 assays, such as the reproducibility and the dilution test. Many patients with breast cancer had elevated serum CA549 concentrations and significant correlation was observed between serum CA549 and CA15-3 values. Anti-CA549 antibody completely inhibited the binding of 125I-labeled anti-CA15-3 antibody to its antigens. These results suggest that CA549 and CA15-3 antigens have similar immunological characteristics.

Adult↗
PubMed1993

The effect of nutrition on the size and proportion of muscle fibre types during growth.

To investigate whether the retardation in the increase of body weight produced by reduced food intake could influence the transformation of muscle fibre types in soleus and extensor digitorum longus (EDL) during growth, rats were divided into 3 groups at 3 wk of age. Each group was subjected to food restriction from 3 wk of age to the following ages. Group 1 comprised 5 (148.7 +/- 7.3 g), 7 (250.7 +/- 11.1 g), 9 (362.9 +/- 19.3 g) and 11-wk-old rats (414.9 +/- 35.2 g) fed ad libitum. Group 2 comprised 5 (148.7 +/- 7.3 g), 7 (148.6 +/- 7.7 g), 9 (147.7 +/- 6.0 g) and 11-wk-old rats (148.8 +/- 5.7 g) fed a restricted diet; these animals were similar in weight to the 5-wk-old rats in group 1. Group 3 comprised 4 subgroups of 11-wk-old rats (148.7 +/- 5.7 g, 247.6 +/- 6.8 g, 354.4 +/- 8.6 g, 414.4 +/- 35.2 g); their body weights were adjusted to the weights of 5, 7, 9 and 11-wk-old rats in group 1 by restriction of food intake. Muscle weights and fibre areas in soleus and EDL significantly increased with growth. The muscle weights and fibre areas in group 2 in which body weights were equal increased significantly with age, but the increases were significantly less than for group 1. The muscle weights and fibre areas in group 3 in which ages were equal increased significantly with increasing body weight; the increases were the same as those in group 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1992

Expression of p53 protein in colorectal cancer and its relationship to short-term prognosis.

BACKGROUND AND METHODS: The expression of p53 protein in 100 large bowel cancers was studied immunohistochemically by use of a monoclonal antibody (PAb1801). RESULTS: Immunoreactivity was found in 61.0% of specimens from 100 patients with colorectal cancer. The pattern of p53 expression was mainly detected in the nuclei of the cancer cells. There was no significant correlation between the expression of p53 and the histologic grade, tumor size, serosal invasion, lymphatic invasion, venous invasion, lymph node metastasis, or liver metastasis. However, patients with p53-positive tumors had a greater relative risk of death compared with those with p53-negative tumors. The p53 negative-tumors showed a recurrence rate of 5.9%; for the p53 positive-tumors, a recurrence rate of 23.8% was recorded. The 3-year survival rate was 96.7% of 39 patients with p53-negative carcinomas and 61.8% for the patients with p53-positive tumors; there was a significant difference in the rate between the two groups of patients (P < 0.05). The growth fraction of p53-positive tumors determined with a monoclonal antibody against DNA polymerase alpha (49.0%) was significantly higher than that of p53-negative tumors (40.7%, P < 0.01). CONCLUSIONS: These results suggest that the immunoreactivity of p53 may be a biologic marker of prognostic significance.

Analysis of Variance↗
PubMed1992

Metal-tetracycline/H+ antiporter of Escherichia coli encoded by transposon Tn10. The role of a conserved sequence motif, GXXXXRXGRR, in a putative cytoplasmic loop between helices 2 and 3.

The region including the conserved Ser65-Asp66 dipeptide in the tetracycline/H+ antiporter (TET) encoded by transposon Tn10 is thought to play a gating role (Yamaguchi, A., Ono, N., Akasaka, T., Noumi, T., and Sawai, T. (1990) J. Biol. Chem. 265, 15525-15530). The dipeptide is in putative interhelix loop2-3, which also includes the conserved sequence motif, GXXXXRXGRR, found in all TET proteins and sugar/H+ symporters. Through the combination of localized random and site-directed mutagenesis, each residue in loop2-3 was replaced. Among 10 residues in putative loop2-3, the important residues, of which substitution resulted in significant reduction or complete loss of the transport activity, were Gly62, Asp66, Gly69, and Arg70. The defect in the transport activity of the Gly62 and Gly69 substitution mutants corresponded to the steric hindrance by the substituents as to the putative beta-turn structure of the peptide backbone containing these glycines. Of 3 conserved Arg residues, the replacement of only Arg70 caused complete loss of the activity except for replacement with Lys, indicating the importance of a positive charge at this position, which is similar to the essentiality of a negative charge at Asp66. A "charge-neutralizing" intra-loop salt bridge between Asp66 and Arg70 was not likely because the double mutant in which Asp66 and Arg70 were replaced with asparagine and leucine, respectively, showed no transport activity. A triple mutant with only one positive charge at Arg70 in this loop showed about half the wild-type activity, indicating that the polycationic nature of the loop was not critical for the activity. Cys mutants as to the unessential residues in the loop were modifiable with N-ethylmaleimide, except for the Met64----Cys and Arg71----Cys mutants; however, the modification of only the Ser65----Cys mutant caused significant inhibition of the transport activity, indicating that position 65 is a unique position in the structure of loop2-3.

Amino Acid Sequence↗
PubMed1992

Aspartic acid-66 is the only essential negatively charged residue in the putative hydrophilic loop region of the metal-tetracycline/H+ antiporter encoded by transposon Tn10 of Escherichia coli.

Of the 16 acidic amino acid residues located in the hydrophilic region of the metal-tetracycline/H+ antiporter of transposon Tn10, five glutamic acids and three aspartic acids are conserved among the tetracycline/H+ antiporters of Gram-negative bacteria. When these conserved acidic residues were each replaced by a neutral polar residue, glutamine or asparagine, only the Asp66 substitution mutants completely lost their transport activity. The substitution of Glu274, Asp120, Glu181, or Asp38 caused significant reduction of the transport activity, whereas the substitution of the other three residues had no detectable effect on the activity. These findings led to the conclusion that only Asp66 is essential for the transport function.

Amino Acid Sequence↗
PubMed1992

OmpF channel permeability of quinolones and their comparison with beta-lactams.

The diffusion rates of nalidixic acid, ofloxacin and ofloxacin's two optically active isomers through OmpF channels were measured in proteoliposomes and compared with the rates of beta-lactams. The four quinolones showed high diffusion rates, exceeding that of cephaloridine and being comparable to imipenem. There was no significant difference in diffusion rate between nalidixic acid and ofloxacin, or between the two optically active isomers. The diffusion rates of enoxacin and norfloxacin were also estimated to be higher than many beta-lactams.

Anti-Bacterial Agents↗
PubMed1992

Serine residues responsible for tetracycline transport are on a vertical stripe including Asp-84 on one side of transmembrane helix 3 in transposon Tn10-encoded tetracycline/H+ antiporter of Escherichia coli.

Putative transmembrane helix 3 of the tetracycline/H+ antiporter encoded by a transposon, Tn10, contains four serine residues, Ser-77, Ser-82, Ser-91 and Ser-92. Each of these serine residues was replaced by site-directed mutagenesis. Of these four serine residues, Ser-77 was important for the transport function, and a bulky side chain at position 91 hindered substrate translocation, whereas Ser-82 and Ser-92 did not play any role. Ser-77 and Ser-91 are on the same vertical stripe, that includes the essential Asp-84, on the hydrophilic side of putative helix 3. These observations suggest that helix 3 is part of the tetracycline translocation channel across the membrane.

Alanine↗
PubMed1992

M-phase-specific histone H1 kinase in fish oocytes. Purification, components and biochemical properties.

We demonstrate, for the first time in fish, that a Ca(2+)-independent and cyclic-nucleotide-independent histone H1 kinase activity oscillates according to the cell cycle of the oocyte, peaking at the first and the second meiotic metaphase with a transient drop between them. The kinase, M-phase-specific histone H1 kinase (M-H1K), was purified from mature carp oocytes by using two exogenous substrates for assaying its activity: histone H1 and a synthetic peptide (SP peptide, KKAAKSPKKAKK) containing the sequence KSPKK, which includes the consensus sequence of the site phosphorylated by a serine/threonine-specific protein kinase encoded by the fission yeast cdc2+ gene (cdc 2 kinase). The M-H1K and maturation-promoting factor (MPF) activities coincided closely throughout four steps of purification, strongly suggesting the identity of M-H1K and MPF. The final preparation was purified 5000-fold with a recovery of 4%, when histone H1 was used for the kinase assay, and 10,000-fold with a recovery of 7% when SP peptide was used. The purified molecular mass of the kinase was estimated to be 100 kDa by gel filtration and contained four proteins of 33, 34, 46 and 48 kDa. Anti-PSTAIR antibody recognizing cdc2 kinase cross-reacted with the 33-kDa and 34-kDa proteins, while the 46-kDa and 48-kDa bands cross-reacted with monoclonal antibodies raised against cyclin B. The 33-kDa protein was also recognized by an antibody against a goldfish cdk2 (Eg1) kinase, a cdc2-related kinase which has the PSTAIR sequence and binds to p13suc1 but does not form a complex with cyclin B. M-H1K activity corresponded well to the 34-kDa, 46-kDa and 48-kDa proteins but not to the 33-kDa protein. These results strongly suggest that M-H1K consists of cdc2 kinase forming a complex with cyclin B, and that cdk2 kinase is not a component of M-H1K, although it is found in the highly purified M-H1K. The purified M-H1K utilized Mg2+, Mn2+, ATP and GTP, and had a wide pH optimum ranging over 8.0-10.5. The kinase was thermolabile and sensitive to freezing/thawing.

Amino Acid Sequence↗
PubMed1992

Metal-tetracycline/H+ antiporter of Escherichia coli encoded by transposon Tn10. Roles of the aspartyl residues located in the putative transmembrane helices.

Three conserved aspartyl residues located in the putative transmembrane helices in the Tn10-encoded metal-tetracycline/H+ antiporter were replaced by Asn, Lys, or Glu with oligonucleotide-directed site-specific mutagenesis. Replacement of Asp84 or Asp15 by Asn or Lys caused a severe defect in tetracycline transport activity, however, the Glu84 and Glu15 mutants retained 150 and 40% of the wild type activity, respectively, indicating the critical role of the negative charge. The increase in the activity of the Glu84 mutant was due to an increase in the affinity for the substrate. H+/tetracycline coupling was intact in these mutants, including Asn and Lys mutants. On the other hand, all of the Asp285-substitution mutants showed a severe defect in tetracycline transport activity and a complete lack of tetracycline-coupled H+ transport. However, since in vivo tests showed the tetracycline resistance for the Glu285 mutant, a negative charge in position 285 plays some role in maintaining the possible down-hill and/or low affinity efflux of accumulated tetracycline from intact cells. Similar work was done for Asp365, and here the Asn and Glu mutants showed decreased but high activity, while the Lys mutant was only marginally active (5%), indicating that a negative charge is not so demanding in position 365, possibly because it is not in the membrane.

Amino Acid Sequence↗
PubMed1992

Preparation and characterization of a mouse osteoclast-like multinucleated cell population.

We have reported that numerous tartrate-resistant acid phosphatase-positive osteoclast-like multinucleated cells (TRAP+ MNCs) are formed when mouse osteoblastic cells and spleen cells are cocultured in the presence of 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] (Endocrinology 123:2600, 1988). In this study, we prepared a TRAP+ MNC population using a modified coculture system and examined its osteoclastic properties. TRAP+ MNCs were formed in cocultures of mouse osteoblastic cells and marrow cells on 10 cm collagen gel-coated dishes. The TRAP+ MNC population was prepared by treating the dishes with 0.2% bacterial collagenase followed by density gradient centrifugation. The yield of TRAP+ MNCs was 20,000-40,000 cells per dish, much higher than that of osteoclasts (OCLs) isolated from neonatal rat bones (approximately 1000 cells per head). The purity of TRAP+ MNCs was 5.6 +/- 0.6% in cell number and about 30% in the number of nuclei. The recovery of TRAP+ MNCs after density gradient centrifugation was 30-40%. Acid production by MNCs was demonstrated by vital staining with acridine orange. Numerous resorption pits were formed when the MNC population was cultured for 48 h on bone slices. Autoradiography using [125I]salmon calcitonin (CT) showed abundant CT binding in most TRAP+ MNCs. Saturation analysis of [125I]salmon CT indicated a dissociation constant Kd for TRAP+ MNCs of 8.9 +/- 0.7 x 10(-10) M and 16.5 +/- 1.5 x 10(6) binding sites per cell. These results were similar to the Kd value (3.5 x 10(-10) M) and the number of binding sites (3.3 x 10(6) per cell) in isolated rat OCLs. Displacement curves for [125I]salmon CT with unlabeled salmon and human CT were similar in MNC and OCL preparations. Salmon and human CT increased cAMP production (maximal response: slmon CT at 10(-10) M, human CT at 10(-8) M; ED50s: salmon CT, 2.2 x 10(-11) M, human CT, 1.3 x 10(-9) M) in the MNC preparation. These results indicate that a large number of mouse TRAP+ MNCs possessing OCL characteristics can be easily prepared from in vitro cultures. This procedure will facilitate examination of mammalian OCL functions.

Acid Phosphatase↗
PubMed1992

Studies on the participation of different T cell subsets in rat liver allograft rejection. Comparison of liver with heart graft.

In this study, we investigated which subsets of rat T cells (CD8+ vs. CD4+) are involved in the rejection of liver allografts by the in vivo administration of monoclonal antibody (OX-8 or OX-38, and W3/25 MAb) into thymectomized recipient Lewis (RTI(l)) rats prior to DA (RTI(a)) liver transplantation. We also compared the results of allograft survival of liver and heart transplants under the same experimental conditions. In order to deplete either CD8+ T cells or CD4+ T cells from recipient animals, 0.4 ml of OX-8 (ascitic form) or a 0.8 ml cocktail of MAb W3/25 and OX-38 (0.4 ml each) was injected into thymectomized recipient rats, respectively. Untreated Lewis rats consistently rejected donor DA liver grafts between 9 and 11 days (n = 7, 9.8 days +/- 1.1 days). In contrast, anti-CD8 MAb pretreatment extended the survival times of DA liver grafts for up to 40 days (n = 5, 26.8 days +/- 8.4 days). Furthermore, survival of DA liver grafts was significantly prolonged in Lewis rats that had been pretreated with anti-CD4 MAb (n = 7, 35.6 days +/- 17.9 days). Two out of seven recipient animals survived for more than 60 days. For heart transplantation, untreated Lewis rats rejected DA heart grafts between 6 and 8 days after operation (n = 6, 6.5 days +/- 1.2 days). Anti-CD4 MAb treatment prolonged heart graft survival for more than 60 days in all cases (n = 3, > 60 days). However, there was virtually no effect of anti-CD8 MAb treatment on heart graft survival (n = 4, 7.0 days +/- 0.9 days). These results suggested that when whole MHC disparity prevailed between donor and recipient, both subsets of T cells were required for the rejection of liver allografts and that class II reactive T cells predominantly mediated liver graft rejection. Furthermore, CD8+ T cells played a differential role in the rejection of rat liver and heart allograft.

Animals↗
PubMed1992

Independent clinical and flow cytometric prognostic factors for the survival of patients with stage I gastric cancer.

Paraffin-embedded tumor samples from 151 patients with stage I gastric cancer were analyzed by DNA flow cytometry, and 80 patients received an infusion of bromodeoxyuridine (BrdU) to determine S-phase fraction. S-phase fractions of tumors were measured by the immunohistochemical method using anti-BrdU monoclonal antibody. Of the 151 patients, 81 (54%), and 70 (46%) showed diploid and aneuploid patterns. There was no significant association between DNA ploidy and wall invasion, histologic type, or lymphatic invasion. Aneuploid tumors were associated with positive-vessel invasion. When the DNA ploidy and clinicopathological parameters were simultaneously entered into the Cox regression model, DNA ploidy and wall invasion emerged as independent prognostic parameters. Aneuploid tumors had significantly higher values of BrdU labeling indices than diploid ones. These results indicate that the determination of DNA ploidy patterns may be an important prognostic factor in patients with stage I gastric cancer, and may be useful in deciding the therapeutic schedule of patients with gastric cancer.

Aneuploidy↗
PubMed1992

Intraperitoneal hyperthermic treatment for peritoneal dissemination of colorectal cancers.

Continuous hyperthermic peritoneal perfusion (CHPP) combined with administration of anticancer drugs was performed in eight colorectal cancer patients with peritoneal dissemination. An overall response rate of 50 percent was achieved in the eight patients. Two of three complete responders are long, recurrence-free survivors for 15 and 30 months. The two-year survival has been achieved in 18.8 percent of the patients receiving CHPP, and this rate is significantly higher than the rates in P2 and P3 patients who did not receive CHPP. The complications of CHPP with administration of anticancer drugs were mild bone marrow suppression in two (25 percent) of the eight patients and also a mild grade of renal dysfunction in one (12.5 percent), though not lethal. The results suggest that the combination of CHPP with the administration of anticancer drugs is a safe and effective therapy for peritoneal dissemination of colorectal cancers.

Adult↗
PubMed1992

Carcinoma in situ of the gallbladder with superficial extension into the Rokitansky-Aschoff sinuses and mucous glands.

Twenty-four cases of carcinoma in situ of the gallbladder encountered over the past 29 years were evaluated histopathologically. Macroscopic classification disclosed 12 protruding types and 12 superficial types (7 elevated types and 5 flat types). Histologically, 18 cases had papillary growth and 6 had tubular patterns. Epithelial dysplasia of varying degrees was observed around the carcinoma in situ in all except one case and was seen more extensively in superficial type cases, although it was often hard to distinguish dysplasia from carcinoma in situ in some cases. Metaplasia of the mucous glands was observed in 20/24 cases (83.3%). Superficial extension of carcinoma in situ into the Rokitansky-Aschoff sinuses (located below the muscle layer) was observed in 11 cases (45.8%), and extension into the mucous glands was seen in 8 cases (33.3%). These results indicate that it is very important to be able to differentiate invasive carcinoma from cases with superficial extension of dysplasia and/or carcinoma in situ deep into the mucous glands or Rokitansky-Aschoff sinuses. Histological assessment should also be conducted carefully while considering these factors.

Carcinoma in Situ↗