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Biomedical subjects

A Sakamoto

Publications and source records attributed to A Sakamoto.

At least 19 recordsLinked to original sources
PubMed2001

Conservative therapy for adenocarcinoma and atypical endometrial hyperplasia of the endometrium in young women: central pathologic review and treatment outcome.

Thirty-nine patients with endometrioid adenocarcinoma (EA) and atypical hyperplasia (AH) of the endometrium who received conservative treatment to preserve fertility were collected from member institutions of the Japan Gynecologic Oncology Study Group. Twenty-nine and ten were originally diagnosed with EA without myometrial invasion and AH, respectively. We performed a central pathological review to make definite diagnoses, and the diagnosis of EA in 29 cases was changed to AH in ten, complex hyperplasia in three and atypical polypoid adenomyoma in three, and AH in ten was changed to EA in one and simple hyperplasia in one. Nine of 12 women (75%) with EA and 15 of 18 women (83%) with AH had an initial response to medroxyprogesterone acetate (MPA) treatment. Two of nine responders with EA later developed relapse, and one of them had metastasis to the left obturator lymph node. Two became pregnant, and one delivered one full-term infant. One of the responders with AH had a relapse in the endometrium. Five became pregnant, and four delivered four normal infants. The young women with endometrial carcinoma localized in the endometrium who wish to preserve fertility may be treated as successfully with MPA as those with AH.

Adenocarcinoma↗
PubMed2001

Glomangiopericytoma causing oncogenic osteomalacia. A case report with immunohistochemical analysis.

A 47-year-old woman suffered from gait disturbance due to back pain and muscle weakness. Laboratory data showed serum hypophosphatemia, elevated alkaline phosphatase, and a normal level of ionized calcium. Radiological examinations revealed multiple pathologic fractures in the ribs and pubic rami. She had had no episode of familial or any other notable disorder, and so she was initially treated with medication for adult-onset osteomalacia. However, 19 years later (when she was 66 years old), she noticed a soft-tissue tumor in her buttock. The tumor was excised. The histological features were those of glomangiopericytoma characterized by both glomus tumor-like and hemangiopericytoma-like structures. After removal of the tumor, her symptoms disappeared immediately. Laboratory data normalized 8 months later. To our knowledge, this is the first report of oncogenic osteomalacia caused by glomangiopericytoma.

Aged↗
PubMed2001

H-ras oncogene mutation in dedifferentiated chondrosarcoma: polymerase chain reaction-restriction fragment length polymorphism analysis.

Dedifferentiated chondrosarcomas, which are known for their poor prognosis, are characterized by conventional chondrosarcoma with high-grade anaplastic components. Activating mutations in ras genes are a common genetic abnormality in human malignancies. The presence of point mutations at codons 12 and 13 of the H-ras gene was studied in 20 formalin-fixed paraffin-embedded chondrosarcomas, comprising 11 cases of conventional chondrosarcoma (six Grade 1 cases and five Grade 2 cases) and nine cases of dedifferentiated chondrosarcoma, using polymerase chain reaction-restriction fragment length polymorphism and direct sequencing analysis. H-ras mutations were only seen in two out of the nine cases of dedifferentiated chondrosarcoma (2/9, 22%) and they were not seen in any of the cases of conventional chondrosarcoma (0/11, 0%). Dedifferentiated chondrosarcomas had a worse prognosis than conventional chondrosarcomas (P < .01); among the patients with dedifferentiated chondrosarcomas, those with H-ras mutation (n = 2) tended to have a worse prognosis than those without (n = 7), although the difference was not statistically significant (P = 0.068). Our results would seem to suggest that H-ras mutation may occur during the course of dedifferentiation and may also have some effect on malignant potential.

Adult↗
PubMed2001

Functional expression in Escherichia coli of low-affinity and high-affinity Na(+)(Li(+))/H(+) antiporters of Synechocystis.

Synechocystis sp. strain PCC 6803 has five genes for putative Na(+)/H(+) antiporters (designated nhaS1, nhaS2, nhaS3, nhaS4, and nhaS5). The deduced amino acid sequences of NhaS1 and NhaS2 are similar to that of NhaP, the Na(+)/H(+) antiporter of Pseudomonas aeruginosa, whereas those of NhaS3, NhaS4, and NhaS5 resemble that of NapA, the Na(+)/H(+) antiporter of Enterococcus hirae. We successfully induced the expression of nhaS1, nhaS3, and nhaS4 under control of an Na(+)-dependent promoter in Escherichia coli TO114, a strain that is deficient in Na(+)/H(+) antiport activity. Inverted membrane vesicles prepared from TO114 nhaS1 and TO114 nhaS3 cells exhibited Na(+)(Li(+))/H(+) antiport activity. Kinetic analysis of this activity revealed that nhaS1 encodes a low-affinity Na(+)/H(+) antiporter with a K(m) of 7.7 mM for Na(+) ions and a K(m) of 2.5 mM for Li(+) ions, while nhaS3 encodes a high-affinity Na(+)/H(+) antiporter with a K(m) of 0.7 mM for Na(+) ions and a K(m) of 0.01 mM for Li(+) ions. Transformation of E. coli TO114 with the nhaS1 and nhaS3 genes increased cellular tolerance to high concentrations of Na(+) and Li(+) ions, as well as to depletion of K(+) ions during cell growth. To our knowledge, this is the first functional characterization of Na(+)/H(+) antiporters from a cyanobacterium. Inverted membrane vesicles prepared from TO114 nhaS4 cells did not have Na(+)/H(+) antiport activity, and the cells themselves were as sensitive to Na(+) and Li(+) ions as the original TO114 cells. However, the TO114 nhaS4 cells were tolerant to depletion of K(+) ions. Taking into account these results and the growth characteristics of Synechocystis mutants in which nhaS genes had been inactivated by targeted disruption, we discuss possible roles of NhaS1, NhaS3, and NhaS4 in Synechocystis.

Amino Acid Sequence↗
PubMed2001

H-ras oncogene mutation in dedifferentiated liposarcoma. Polymerase chain reaction-restriction fragment length polymorphism analysis.

Point mutations of the ras gene family (K-ras, H-ras, and N-ras) are thought to be involved in the development of a variety of human tumors. Dedifferentiated liposarcoma is characterized by the coexistence of well-differentiated (WD) and high-grade anaplastic (HG) components. The presence of point mutations at codons 12 and 13 of the H-ras gene was studied in 34 liposarcomas, comprising 15 well-differentiated liposarcomas and 19 dedifferentiated liposarcomas, and in 8 storiform-pleomorphic type malignant fibrous histiocytomas (MFHs) using polymerase chain reaction-restriction fragment length polymorphism and direct sequencing analysis. The 2 components of dedifferentiated liposarcoma were analyzed independently. H-ras mutations were seen only in dedifferentiated liposarcomas (4/19 [21%]), 1 in WD components and 3 in HG components. The mutation was not seen in any of 15 cases of well-differentiated liposarcoma. MFHs showed an H-ras mutation in 1 (12%) of 8 cases. Our results seem to suggest that the H-ras mutation is a relatively uncommon event in dedifferentiated liposarcoma, which may demonstrate an epiphenomenon of dedifferentiation in dedifferentiated liposarcoma.

Adult↗
PubMed2001

Selective reduction and recovery of invariant Valpha24JalphaQ T cell receptor T cells in correlation with disease activity in patients with systemic lupus erythematosus.

OBJECTIVE: To study the regulatory role of CD4-CD8- double-negative (DN) invariant T cell receptor (TCR) Valpha24JalphaQ T cells, a human counterpart of murine NK 1 + T cells, in the autoimmune process of systemic lupus erythematosus (SLE). METHODS: We carried out a 2 step frequency analysis of DN Valpha24JalphaQ T cells in patients with SLE before and after prednisolone therapy; the frequency of DN Valpha24+ T cells was determined by 3 color FACS analysis and subsequently the frequency of Valpha24JalphaQ rearrangement among DN Valpha24+ T cells was determined by sequencing. RESULTS: DN Valpha24+ T cells were significantly increased in patients with active SLE compared to healthy subjects. In healthy subjects, invariant Valpha24JalphaQ TCR dominated in DN Valpha24+ T cells at a high frequency (93-100%). However, the invariant Valpha24JalphaQ TCR was not detected in DN Valpha24+ T cells from patients with active SLE, and instead 2 to 9 Jalpha genes other than the invariant JalphaQ were oligoclonally expanded in the patients. In inactive SLE induced by prednisolone therapy, the invariant Valpha24JalphaQ TCR could be detected in DN Valpha24+ T cells from all the patients and dominated in most of the patients. Further, oligoclonally expanded Valpha24+ clones other than the invariant JalphaQ gene in active disease states were significantly decreased by prednisolone therapy. CONCLUSION: The selective reduction of DN invariant Valpha24JalphaQ T cells is related to the disease progression of SLE, while DN TCR Valpha24 T cells other than Valpha24JalphaQ T cells constitute autoaggressive T cells in SLE.

Adult↗
PubMed2000

C(2)-Symmetric bis-sulfoxide: A novel chiral auxiliary for asymmetric desymmetrization of cyclic meso-1,2-diols

A new heterocyclic compound, C(2)-symmetric bis-sulfoxide 1, has been found to be an efficient chiral auxiliary for asymmetric desymmetrization of cyclic meso-1,2-diols via diastereoselective acetal fission. Both (R,R)- and (S,S)-1 are readily synthesized with high optical purity via asymmetric oxidation of 1, 5-benzodithiepan-3-one (2). After acetalization of meso-1,2-diols 6a-e and a mono-TMS ether 6f with this chiral auxiliary 1, the resulting acetals 7a-f were subjected to base-promoted acetal fission upon treatment with potassium hexamethyldisilazide (KHMDS) followed by acetylation or benzylation to give the desymmetrized diol derivatives 8a-f with high diastereoselectivity. The chiral auxiliary 1 is readily removed by acid-promoted hydrolysis and can be recovered without a loss in enantiomeric excess.

Journal Article↗
PubMed2000

Control of homeostasis of CD8+ memory T cells by opposing cytokines.

Memory T cells maintain their numbers for long periods after antigen exposure. Here we show that CD8+ T cells of memory phenotype divide slowly in animals. This division requires interleukin-15 and is markedly increased by inhibition of interleukin-2 (IL-2). Therefore, the numbers of CD8+ memory T cells in animals are controlled by a balance between IL-15 and IL-2.

Animals↗
PubMed2000

Prognostic value of the preserved expression of the E-cadherin and catenin families of adhesion molecules and of beta-catenin mutations in synovial sarcoma.

This study addresses the immunohistochemical expression of the E-cadherin and catenin families and mutations of the beta-catenin gene detected by PCR-SSCP in synovial sarcoma. Immunohistochemical analysis was performed for 72 cases, with follow-up data available on 62. The prognostic value of the expression of these proteins was evaluated. Reduced immunoreactivity for E-cadherin and alpha-catenin was significantly correlated with a poor survival rate (p=0.0040 and 0.0053, respectively). According to multivariate analysis, low AJC stage (stages I and II: p<0.0001), the preservation of alpha-catenin expression (p=0.0001), and a low necrotic rate (<50%: p=0.0139) were independent favourable prognostic factors. Widespread aberrant staining of beta-catenin protein within cytoplasm and/or nuclei was observed in 28 cases (38.9%) and was significantly correlated with poor survival (p=0.0122). In addition, there was a trend towards a correlation between widespread aberrant staining of beta-catenin and the MIB-1 labelling index (p=0.0535). Mutational analysis of exon 3 of the beta-catenin gene was performed for 49 cases. Nucleotide sequencing analysis revealed that four (8.2%) contained point mutations (three in codon 32, GAC to TAC; one in codon 37, TCT to TTT). Survival data were available for three out of four cases with beta-catenin mutations; two of these patients died within 1 year (died of disease at 6 and 11 months, respectively). These results suggest that E-cadherin and alpha-catenin undertake important roles as intercellular adhesion molecules; their preserved expression is associated with a better overall survival rate in synovial sarcoma and may have prognostic value. Abnormal levels of beta-catenin, with or without mutation, could contribute to the development and progression of synovial sarcoma, through increasing the proliferative activity of the tumour cells.

Cadherins↗
PubMed2000

Degradation of the metal-cyano complex tetracyanonickelate (II) by Fusarium oxysporum N-10.

A fungus with the ability to utilize a metalcyano compound, tetracyanonickelate (II) ¿K2[Ni (CN)4]; TCN¿, as its sole source of nitrogen was isolated from soil and identified as Fusarium oxysporum N-10. Both intact mycelia and cell-free extract of the strain catalyzed hydrolysis of TCN to formate and ammonia and produced formamide as an intermediate, thereby indicating that a hydratase and an amidase sequentially participated in the degradation of TCN. The enzyme catalyzing the hydration of TCN was purified approximately ten-fold from the cell-free extract of strain N-10 with a yield of 29%. The molecular mass of the active enzyme was estimated to be 160 kDa. The enzyme appears to exist as a homotetramer, each subunit having a molecular mass of 40 kDa. The enzyme also catalyzed the hydration of KCN, with a cyanide-hydrating activity 2 x 10(4) times greater than for TCN. The kinetic parameters for TCN and KCN indicated that hydratase isolated from F. oxysporum was a cyanide hydratase able to utilize a broad range of cyano compounds and nitriles as substrates.

Amino Acid Sequence↗
PubMed2000

Plasma total glutathione concentrations in epileptic patients taking anticonvulsants.

Glutathione plays an important role in protecting cells against oxidative damage as a free radical scavenger. Since several anticonvulsants have been associated with decreased intrahepatic glutathione levels, we investigated plasma concentrations of total glutathione (including reduced and oxidized forms, tGSH=GSH+GSSG) in 45 epileptic patients taking anticonvulsant drugs. Plasma tGSH concentrations were significantly lower than in controls in patients treated with carbamazepine or phenytoin monotherapy, or with multiple drugs. Plasma tGSH concentrations in patients treated with valproic acid and in patients treated with phenobarbital did not differ significantly from those in controls. In no patient group was a significant correlation evident between duration of treatment or drug concentration and plasma tGSH concentration. No significant differences in plasma total cysteine concentrations were found between any patient group and controls. We conclude that some anticonvulsant drugs can lower plasma tGSH levels, reflecting treatment-related oxidative stress.

Adolescent↗
PubMed2000

Expression of hepatocyte growth factor (HGF)/scatter factor and its receptor c-MET correlates with poor prognosis in synovial sarcoma.

The hepatocyte growth factor (HGF)/c-MET signaling system plays an important role in the carcinogenesis of various organs. We investigated the expression of HGF and its receptor c-MET by immunohistochemistry (IHC) in 69 cases of synovial sarcoma and compared the findings with clinicopathologic parameters, proliferating activities evaluated by MIB-1 labeling index (MIB-1 LI), and patients' prognosis. Furthermore, mRNA analysis of HGF, c-MET, and SYT-SSX fusion gene was performed by reverse transcriptase-polymerase chain reaction (RT-PCR) in 22 concordant frozen materials. Twenty-one of 69 (30.4%) tumors showed positive reaction for c-MET, whereas 22 tumors (31.9%) were positive for HGF. In 10 cases, co-expression of HGF and c-MET was observed; however, there was no significant correlation between HGF and c-MET expression. HGF expression was correlated with female patients, large tumors (more than 5 cm), the presence of rhabdoid cells, low frequency of mast cells (<20/10 HPF), high nuclear grade (grade III), and high American Joint Committee (AJC) stage (III and IV). Conversely, c-MET expression was only correlated with large tumors. However, the coexpression of HGF and c-MET was significantly correlated with large tumor size, the existence of rhabdoid cells, and high AJC stage. Both the expression of HGF and the co-expression of HGF and c-MET showed a significantly high MIB-1 LI and were correlated with poor prognosis according to univariate analysis. Multivariate Cox analysis showed that high AJC stage, the expression of HGF, and a high MIB-1 LI (12.0>) independently had a negative impact on overall survival. In 22 frozen material cases evaluated by both IHC and RT-PCR, a statistically significant correlation was found between the 2 techniques. SYT-SSX fusion transcripts were detected in all 22 cases. Three tumors had SYT-SSX2 fusion transcripts, whereas 19 had SYT-SSX1 phenotype. Our results suggest that HGF/c-MET paracrine signaling may contribute to tumorigenesis and progression in synovial sarcoma.

Adult↗
PubMed2000

Role of ras mutation in the progression of thyroid carcinoma of follicular epithelial origin.

The histological differentiation of thyroid carcinoma is known to correlate with prognosis. Ras oncogene mutations, which have been identified in various human cancers, have been suspected playing an important role in carcinogenesis and tumor progression. The purpose of this study was to clarify the mechanism of thyroid tumor progression, focusing on ras oncogenes. We examined ras mutations using nested polymerase chain reaction (PCR) and direct sequencing methods. The ras oncogene product was also examined immunohistochemically. Our results indicated that the incidence of ras mutations correlated with the histological differentiation of thyroid cancer. Three poorly differentiated carcinomas showed a higher rate of ras mutations than did 17 well-differentiated counterparts. Hot spots were not identified except for a relative accumulation of the N-ras gene at codon 61. There was a correlation between the immunoreactivity of the ras oncogene product and ras mutation, although the immunoreactivity of ras-p21 did not correlate with the histological differentiation. Mutation of the ras gene seemed to be one of the important events in the progression from well-differentiated carcinoma to poorly differentiated thyroid carcinoma.

Adenocarcinoma, Follicular↗
PubMed2000

Minor cardiac troponin T release in patients undergoing coronary artery bypass graft surgery on a beating heart.

OBJECTIVES: To determine whether and to what extent coronary artery bypass graft (CABG) surgery without extracorporeal circulation is associated with cardiac troponin T (TnT) release. DESIGN: Prospective study. SETTING: A single university hospital. PARTICIPANTS: Twenty-three patients scheduled for minimally invasive CABG surgery. Sixteen patients received one coronary anastomosis, and seven received two. INTERVENTIONS: TnT and creatine kinase-MB (CK-MB) levels were determined immediately before induction of anesthesia (baseline) and at 0, 12, and 24 hours after surgery. Hemodynamic measurements were made, and 5-lead electrocardiograms with continuous automated ST-segment trends were analyzed. MEASUREMENTS AND MAIN RESULTS: All patients had a good cardiac outcome. Median cumulative coronary artery occlusion time was 27 minutes (range, 10 to 49 minutes). TnT levels were undetectable in 91.3% of patients at baseline when a detection limit of 0.01 ng/mL was employed. TnT and CK-MB showed significant elevations at 12 and 24 hours versus baseline. Postoperatively, TnT was detectable in 91.3% of patients, and 17.4% suffered minor myocardial damage, as evidenced by an abnormal increase in TnT greater than 0.2 ng/mL, excluding those exhibiting myocardial infarction. ST segment changes developed in seven patients, persisting for 13.0 minutes (range, 9.5 to 15.8 minutes) and disappearing immediately after coronary artery clamp release. There were no significant correlations between cumulative coronary occlusion time and peak TnT or CK-MB levels. CONCLUSIONS: TnT was detected after surgery in most patients, and significant TnT levels indicative of myocardial injury (>0.2 ng/mL) were detected in only 17% of patients, probably as a result of brief periods of coronary artery occlusion.

Adult↗
PubMed2000

A comparative study of fibrous dysplasia and osteofibrous dysplasia with regard to Gsalpha mutation at the Arg201 codon: polymerase chain reaction-restriction fragment length polymorphism analysis of paraffin-embedded tissues.

Fibrous dysplasia and osteofibrous dysplasia are both benign fibro-osseous lesions of the bone and are generally seen during childhood or adolescence. Histologically, the features of these bone lesions sometimes look quite similar, but their precise nature remains controversial. Mutation of the alpha subunit of signal-transducing G proteins (Gsalpha), with an increase in cyclic adenosine monophosphate (cAMP) formation, has been implicated in the development of multiple endocrinopathies of the Albright-McCune syndrome and in the development of fibrous dysplasia. We studied Gsalpha mutation at the Arg201. codon in seven cases of fibrous dysplasia (six monostotic lesions and one polyostotic lesion) and seven cases of osteofibrous dysplasia using formalin-fixed, paraffin-embedded tissue, by means of polymerase chain reaction-restriction fragment length polymorphism and direct sequencing analysis. All of the seven cases of fibrous dysplasia showed missense point mutations in Gsalpha at the Arg201 codon that resulted in Arg-to-His substitution in three cases and Arg-to-Cys substitution in four cases. On the other hand, the seven cases of osteofibrous dysplasia and the normal bone used as a control showed no such mutation. These data suggest that fibrous dysplasia and osteofibrous dysplasia have different pathogeneses and that the detection of Gsalpha mutation at the Arg201 codon is quite useful for distinguishing between these lesions.

Adolescent↗
PubMed2000

Homeostasis of alpha beta TCR+ T cells.

Cytokines contribute to T cell homeostasis at all stages of T cell existence. However, the particular cytokine involved varies as T cells progress from a naïve through an activated to a memory state. In many cases the important cytokines are members of the interleukin 2 subfamily of the short-chain type I cytokines. A case is made for the idea that the evolutionary divergence of the short-chain family allowed for concurrent divergence in leukocytes.

Animals↗