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Biomedical subjects

H Maruyama

Publications and source records attributed to H Maruyama.

At least 37 records · Page 2Linked to original sources
PubMed2003

Development of hungry bone syndrome after rapid lowering of PTH with intravenous maxacalcitol therapy in a patient with non-uremic secondary hyperparathyroidism.

A 41 year-old woman complained of general bone pain and polyuria. She did not have Albright hereditary osteodystrophy. Laboratory examination revealed hypokalemia, hypocalcemia, and an elevation of serum intact PTH concentration. The patient was polyuric and relatively hypercalciuric, though her glomerular filtration rate (GFR) was normal. Neither urinary Pi nor cAMP excretion was remarkably promoted by an exogenous PTH load. An iliac bone biopsy revealed osteopenia, active osteoclastic bone resorption, fibrous transformation in bone marrow tissue, and severely disturbed calcification. Although the oral administration of alfacalcidol showed no effects, 3 weeks of intermittent intravenous injection of maxacalcitol therapy decreased the serum intact PTH concentration from 597 pg/ml to 40 pg/ml, and the bone pain was greatly relieved. However, plasma Ca concentration also decreased and symptoms of tetany appeared. Pseudohypoparathyroidism type Ib was the most likely diagnosis in this patient. In conclusion, maxacalcitol therapy satisfactorily suppressed parathyroid function in a patient with secondary hyperparathyroidism without uremia. Appropriate Ca supplementation was required to perform it safely.

Adult↗
PubMed2003

A case of adenocarcinoma of the endometrial type mixed with a clear cell component that metastasized to the vagina.

We present a patient with adenocarcinoma of the endometrial type mixed with a clear cell component (AMC) that metastasized to the vagina and one of the pelvic lymph nodes. She underwent a radical hysterectomy and pelvic and paraaortic lymphadenectomy, and then received postoperative adjuvant chemotherapy. Histologic features of the endometrial tumor included clear cell adenocarcinoma with an approximate 10% extent to endometrioid adenocarcinoma. On the other hand, histologic examination on the vaginal tumor predominatly showed clear cell adenocarcinoma and also revealed endometrioid adenocarcinoma to a very small extent, suggesting metastasis to the vagina from AMC. On immunohistochemical examination, expression of vascular endothelial growth factor (VEGF)-A, VEGF-C and VEGF-D was apparently stronger in the component of clear cell adenocarcinoma than in that of endometrioid adenocarcinoma. She has been a disease-free survivor for 26 months. Interestingly, locations of endometrial and vaginal lesions were consistent with the sites of an intrauterine device and ring pessary insertion, respectively.

Adenocarcinoma, Clear Cell↗
PubMed2002

Picosecond snapshot of the speckles from ferroelectric BaTiO3 by means of x-ray lasers.

A picosecond x-ray laser speckle has been conducted to study the dynamics of a disordered surface domain structure (BaTiO3 with 90 degrees c/a domains) as a function of temperature for the first time. The transient surface structures induced by ferroelectric domains decrease as temperature increases towards the Curie temperature T(c) and completely disappear above T(c). The dramatic change of the spatial configuration of the c/a domains was observed to occur from a temperature 2 degrees C below T(c), near which the average correlated domain size at equilibrium decreases as (T(c)-T)(0.37+/-0.02).

Journal Article↗
PubMed2002

Effectiveness of preoperative chemotherapy using carboplatin (CBDCA) and surgery against an esophageal small cell carcinoma.

A 63-year-old man presented to our hospital with persistent dysphagia. Radiologic and endoscopic examination disclosed a 2.0-cm exophytic tumor in the middle third of the esophagus. An endscopically obtained biopsy specimen was found to represent undifferentiated small cell carcinoma. Computed tomography of the chest, abdomen, and cervical region was performed, as were gallium and bone scintigraphy. Metastasis to an adjacent lymph node was detected, without metastasis to distant organs. After neoadjuvant chemotherapy with carboplatin (CBDCA) (400 mg/m2) and etoposide (VP-16) (100 mg/m2), endoscopy and barium-swallow esophagography showed regression. Thoracic esophagectomy then was performed with mediastinal, abdominal and cervical lymph node dissection. The resected tumor was polypoid, measuring 0.5 x 0.5 cm. The lesion consisted mainly of small anaplastic cells, but included a small focus of squamous cell carcinoma. The patient has survived for more than 7 months with no further treatment and no evidence of recurrent disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

Effects of preoperative chemotherapy on metastatic lymph nodes in esophageal squamous cell carcinoma.

The aim of this study was to evaluate the effect of preoperative chemotherapy on metastatic lymph nodes and on the outcome of patients who underwent esophagectomy for advanced squamous cell carcinoma of the esophagus. Fifty-nine patients with potentially resectable squamous cell carcinoma of the esophagus were studied. Twenty patients (group A) were treated by preoperative chemotherapy with cisplatin, 5-fluorouracil, and leucovorin, followed by surgery. Thirty-nine patients underwent surgery alone (group B). A total of 2591 resected lymph nodes were histologically evaluated for metastasis and the effect of chemotherapy. The metastasis rate in the resected lymph nodes, the number of metastatic lymph nodes, and outcome of the patients were statistically analyzed between groups. In group A, the clinical and pathological response rates were 75% and 75% respectively. The metastasis rate in the resected lymph nodes was significantly higher in group B (P < 0.01). The mean number of metastatic lymph nodes was significantly lower in group A (P < 0.05). Furthermore, the mean number of metastatic lymph nodes was significantly lower in the chemotherapy responders than in non-responders. The survival rate in group A was better than in group B (P = 0.07). Preoperative chemotherapy reduced the number of metastatic lymph nodes and may contribute to improving the outcome of the patients who have undergone esophagectomy for squamous cell carcinoma of the esophagus.

Adult↗
PubMed2001

Protection against autoimmune myocarditis by gene transfer of interleukin-10 by electroporation.

BACKGROUND: Although immunosuppressive therapy for myocarditis has attracted a great deal of attention, its effectiveness is controversial. Interleukin (IL)-10 has a variety of immunomodulatory properties. Among the nonviral techniques for gene transfer in vivo, the direct injection of plasmid DNA into muscle is simple, inexpensive, and safe. METHODS AND RESULTS: We examined the applicability of murine IL-10 (mIL-10) gene transfer to the treatment of rats with experimental autoimmune myocarditis. Nine-week-old Lewis rats were inoculated with pig myosin (day 0). A plasmid vector expressing mIL-10 cDNA (800 microgram per rat) was transferred into the tibialis anterior muscles by electroporation 3 times (5 days before immunization and at days 4 and 13); control rats received empty plasmid. Electroporation increased the serum mIL-10 levels to >250 pg/mL. The 21-day survival rate in rats treated with mIL-10 cDNA was higher (15 of 15; 100%) than that of the control group (9 of 15; 60%). Furthermore, mIL-10 treatment significantly attenuated myocardial lesions and improved hemodynamic parameters. CONCLUSIONS: These findings showed that gene transfer into muscle by electroporation in vivo is an effective means of delivery of IL-10 for the treatment of autoimmune myocarditis.

Animals↗
PubMed2001

Activation of preformed EGF receptor dimers by ligand-induced rotation of the transmembrane domain.

The epidermal growth factor receptor plays crucial roles throughout the development of multicellular organisms, and inappropriate activation of the receptor is associated with neoplastic transformation of many cell types. The receptor is thought to be activated by ligand-induced homodimerisation. Here, however, we show by chemical cross-linking and sucrose density-gradient centrifugation that in the absence of bound ligand the receptor has an ability to form a dimer and exists as a preformed dimer on the cell surface. We also analysed the receptor dimerisation by inserting cysteine residues at strategic positions about the putative alpha-helix axis of the extracellular juxtamembrane region. The mutant receptors spontaneously formed disulphide bridges and transformed NIH3T3 cells in the absence of ligand, depending upon the positions of the cysteine residue inserted. Kinetic analyses of the disulphide bonding indicate that EGF binding induces flexible rotation or twist of the juxtamembrane region of the receptor in the plane parallel with the lipid bilayer. The binding of an ATP competitor to the intracellular domain also induced similar flexible rotation of the juxtamembrane region. All the disulphide-bonded dimers had flexible ligand-binding domains with the same biphasic affinities for EGF as the wild-type. These results demonstrate that ligand binding to the flexible extracellular domains of the receptor dimer induce rotation or twist of the juxtamembrane regions, hence the transmembrane domains, and dissociate the dimeric, inactive form of the intracellular domains. The flexible rotation of the intracellular domains may be necessary for the intrinsic catalytic kinase to become accessible to the multiple tyrosine residues present in the regulatory domain and various substrates, and may be a common property of many cell-surface receptors, such as the insulin receptor.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Cholesteryl ester transfer protein deficiency causes slow egg embryonation of Schistosoma japonicum.

In our attempt to discover a potential cause for accumulation of cholesteryl ester transfer protein (CETP) deficiency in Eastern Asia, we studied the association of CETP deficiency with pathogenesis of Schistosoma japonicum, a life-threatening parasite peculiar to this region. The eggs of S. japonicum showed slow embryonation when cultured in CETP-deficient human plasma. Restoration of CETP to the deficient plasma rescued it, while inhibition of CETP in normal plasma did not cause slow embryonation of the cultured eggs. The egg embryonation was also retarded in the liver but not in the intestine of wild-type mice in comparison to the CETP-transgenic mice. The granulomatous lesion around the parasite eggs in the liver was less in the wild-type than in the CETP-transgenic mice. Thus, CETP deficiency may act against Schistosomiasis japonica by retarding egg embryonation, a potential cause of liver granulomatosis. It does not seem directly due to the lack of CETP activity in plasma but to abnormal lipoprotein generated by chronic CETP deficiency.

Animals↗
PubMed2001

Lack of an association between cystatin C gene polymorphisms in Japanese patients with Alzheimer's disease.

Associations between polymorphisms of the cystatin C gene (CST3) at 5' flanking region and exon 1 in Caucasian patients with late onset AD and exon 1 in a US study of late onset AD have been reported. Clinically diagnosed Japanese patients with AD and Japanese normal control subjects were assessed for the presence of polymorphisms of CST3. The authors could not confirm the previously reported association between CST3 polymorphisms and AD in Japan. Age had no effect on the CST3 genotype.

Aged↗
PubMed2001

Glypican-1 is overexpressed in human breast cancer and modulates the mitogenic effects of multiple heparin-binding growth factors in breast cancer cells.

Glypicans are a family of glycosylphosphatidylinositol-anchored cell surface heparan sulfate proteoglycans implicated in the control of cellular growth and differentiation. Here we show that glypican-1 is strongly expressed in human breast cancers, whereas expression of glypican-1 is low in normal breast tissues. In contrast, the expression of glypican-3 and -4 is only slightly increased in breast cancers by comparison with normal breast tissues, and glypican-2 and -5 are below the level of detection by Northern blotting in both normal and cancer samples. Treatment of MDA-MB-231 and MDA-MB-468 breast cancer cells with phosphoinositide-specific phospholipase-C abrogated the mitogenic response to two heparin-binding growth factors, heparin-binding epidermal growth factor-like growth factor and fibroblast growth factor 2. Stable transfection of these cells with a glypican-1 antisense construct markedly decreased glypican-1 protein levels and the mitogenic response to the same heparin-binding growth factors, as well as that to heregulin alpha, heregulin beta, and hepatocyte growth factor. Syndecan-1 was also expressed at high levels in both breast cancer tissues and breast cancer cells when compared with normal breast tissues. There was a good correlation between glypican-1 and syndecan-1 expression in the tumors. However, clones expressing the glypican-1 antisense construct did not exhibit decreased syndecan-1 levels, indicating that loss of responsiveness to heparin-binding growth factors in these clones was not due to altered syndecan-1 expression. Furthermore, 8 of 10 tumors with stage 2 or 3 disease exhibited high levels of glypican-1 by Northern blot analysis. In contrast, low levels of glypican-1 mRNA were evident in 1 of 10 tumors with stage 2 or 3 disease and in 9 of 10 tumors with stage 1 disease. Taken together, these data suggest that glypican-1 may play a pivotal role in the ability of breast cancer cells to exhibit a mitogenic response to multiple heparin-binding growth factors and may contribute to disease progression in this malignancy.

Adult↗
PubMed2001

Influence of interleukin-1beta gene polymorphism on age-at-onset of spinocerebellar ataxia 6 (SCA6) in Japanese patients.

An inverse correlation is observed between the expanded CAG repeat number and age-at-onset of spinocerebellar ataxia 6 (SCA6). To detect another modifying genetic factor for SCA6, we studied polymorphisms in the genes for interleukin (IL)-1beta and tumor necrosis factor in 122 Japanese patients with SCA6. No contribution of these polymorphisms to the variance in disease onset was observed by regression analysis or by ANOVA. The IL-1beta promoter polymorphism, however, significantly affected the age-at-onset, when adjusted for the CAG repeat number as a covariate (P=0.0004, by ANCOVA), suggesting that IL-1beta may be a genetic factor other than the SCA6 gene that modifies the age-at-onset of the disease.

Age of Onset↗
PubMed2001

Genetic studies in Parkinson's disease with an alpha-synuclein/NACP gene polymorphism in Japan.

Dinucleotide repeat polymorphism has been observed in the promoter of the alpha-synuclein (alpha-SYN)/NAC precursor protein (NACP) gene. Alpha-SYN/NACP allele 3 (described by Xia et al. (Ann. Neurol., 40 (1996) 207), equivalent to allele 1 described by Krüger et al. (Ann. Neurol. 45 (1999) 611) is reported to be significantly more frequent among patients with sporadic Parkinson's disease (sPD) than controls. In this study, we genotyped the same alpha-SYN/NACP polymorphism in Japanese sPD patients and healthy controls, but found that any aliele showed no significant difference between the two groups.

Aged↗
PubMed2001

Study of magnetic materials using helicity-modulated X-ray magnetic circular dichroism.

A new helicity-modulation technique has been applied for recording X-ray magnetic circular dichroism (XMCD) at the K-absorption edge in transition-metal magnetic materials. This technique enables the measurement of the XMCD spectrum with high precision and under extreme conditions. The refined spectrum is presented at the Fe K edge for pure Fe, Fe4N and Co-ferrite. The method is very promising for site-assignment of magnetic cations and for detailed investigation of the magnetic states in a local environment. In Mn3MC perovskites, the dependence of the Mn K-edge XMCD spectrum on temperature and magnetic field demonstrates that the orbital moments are closely associated with the magnetic phase transition. New information obtained from the refined spectrum and novel phenomena observed in temperature and field variations is presented.

Journal Article↗
PubMed2001

Multielectron excitations probed by helicity-modulation XMCD at K-edge in 3d transition metal compounds.

Multielectron excitations (MEE) have been investigated using X-ray magnetic circular dichroism (XMCD) at the K-edge in 3d transition metal compounds. In the range of 50-70 eV above the absorption edge, a dichroic signal that is associated with MEE was identified. This phenomenon is thought to occur due to the super Coster-Kronig transition described as the final states (1s)1(3p)5(3d)n+2 resulting from the 3p --> 3d transitions. In order to verify this interpretation, XMCD measurements using the helicity-modulation method and calculations of the dichroic spectrum were performed based on this super Coster-Kronig transition.

Journal Article↗
PubMed2001

Mn K-edge XMCD in Mn3MC (M=Zn and Ga) perovskite.

Mn3MC (M=Zn and Ga) perovskite has attracted interest because of a variety of magnetic phase transitions. In this work, we measure temperature and magnetic field dependence of X-ray magnetic circular dichroism (XMCD) at Mn K-edge and discuss effect of second constituent metal on the magnetic states of Mn atoms. The spectrum in Mn3ZnC is characterized by a dispersion-type profile. In Mn3GaC, intensity of the positive peak at the edge is drastically reduced. The difference originates in charge transfer from Zn or Ga to Mn atoms. Temperature and magnetic field variations of the Mn K-edge XMCD spectrum suggest that orbital magnetic moments are closely related to the magnetic phase transition.

Journal Article↗
PubMed2001

Electronic states in Cu2MnX (X=Al, In, and Sn) Heusler alloy studied by XMCD and multiple scattering calculations.

X-ray magnetic circular dichroism (XMCD) has been measured at Mn and Cu K-edge in Cu2MnX (X=Al, In, and Sn) Heusler alloy. The Mn K-edge spectrum shows a dispersion-type profile and the Cu K-edge resembles the Mn spectrum, which suggests that polarization of the p unoccupied bands originates commonly in Mn 3d states. To reproduce the observed spectrum by full multiple scattering calculations. Madelung potential has been taken into account. Charge redistribution is an important factor for the electronic structure in Cu2MnX Heusler alloy.

Journal Article↗
PubMed2001

Variation of XMCD spectrum with temperature at R L2,3-edges in R3Fe5O12 (R=Gd and Er).

The variation of X-ray magnetic circular dichroism (XMCD) with temperature has been measured at R L2,3-edges in R3Fe5O12 (R=Gd and Er). A drastic change in the spectral profile has been observed at low temperatures. The variation of XMCD peak intensity, corrected by the contribution of Fe with temperature, is in agreement with the magnetization of R sublattice. The results suggest that Fe 3d polarization plays an important role to produce the R L2,3-edges XMCD spectrum.

Journal Article↗