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Biomedical subjects

H Mizuno

Publications and source records attributed to H Mizuno.

At least 73 records · Page 4Linked to original sources
PubMed1999

Sustained contraction to angiotensin II and impaired Ca2+-sequestration in the smooth muscle of stroke-prone spontaneously hypertensive rats.

Contractile response to angiotensin II (AngII) of vascular smooth muscle was compared between 12-week-old, stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto rats (WKY). AngII induced phasic and tonic contraction in denuded aortic ring preparation. The phasic contraction was concentration-dependent (AngII 10(-9) to 10(-6) mol/L) and similar in both strains. However, the relaxation after phasic contraction was significantly attenuated in SHRSP compared with that in WKY. To examine the recovery of contractile responses to the repeated stimulation, AngII was applied three times at 20- and 60-min intervals. The first maximal contraction was similar in both strains, but the response to the second stimulation was significantly reduced in SHRSP, compared with all three responses in WKY. These results suggested that Ca2+-sequestration into the Ca2+ store is delayed in SHRSP. Cyclopiazonic acid (10(-5) mol/L), an intracellular Ca2+-pump inhibitor, decreased spontaneous relaxation and increased the sustained contraction in WKY, whereas it did not affect the contraction in SHRSP. Insulin, which modulates tonic contraction by facilitating Ca2+-extrusion, was applied at peak contraction by AngII. It enhanced relaxation after phasic contraction in a concentration-dependent manner in SHRSP, but it did not affect the relaxation in WKY. These results suggest that increased sustained contraction observed in SHRSP reflects at least partly the impaired Ca2+-pump activity leading to hypertension.

Angiotensin II↗
PubMed1999

Clinical application of biodegradable rib connecting pins in thoracotomy.

BACKGROUND: To assess the usefulness in rib reconstruction of biodegradable connecting pins made of polylactide (PLA), PLA rib pins were compared with conventional non-absorbent aluminous ceramic rib pins (alumina rib pins) in terms of their ability for fixing and healing of cut ribs in thoracic surgery. METHODS: There were 13 cases of rib fixation after thoracotomy using PLA rib pins and 11 cases using alumina rib pins, all of which were inserted into the medulla of the stump of the ribs that had been cut at thoracotomy to secure a larger surgical field. The observation period was 6 months after the operation. RESULTS: The degree of vertical shift of the ribs connected with PLA rib pins was significantly reduced compared with the degree using alumina rib pins. In chest radiographs clear zones around the pins, indicating a delay in bone neogenesis, were observed frequently around the alumina rib pins but were absent around the PLA rib pins. Osteosynthesis using PLA rib pins was significantly more favorable than with alumina rib pins. CONCLUSIONS: These results demonstrated that the PLA rib pin was superior to the alumina rib pin for fixing and healing of the cut rib.

Adult↗
PubMed1999

In-vitro effects of a combination of antipseudomonal antibiotics against multi-drug resistant Pseudomonas aeruginosa.

We evaluated the in-vitro effects of various combinations of five types of widely used antipseudomonal antibiotics (piperacillin, meropenem, ceftazidime, aztreonam and amikacin) against six Pseudomonas aeruginosa strains that were resistant to each of these antibiotics. Among two-drug combinations, the combinations of two beta-lactam antibiotics inhibited growth of one to three P. aeruginosa strains, while those of one beta-lactam antibiotic and amikacin inhibited growth of two to four strains. Among three-drug combinations, the combinations of three beta-lactam antibiotics inhibited growth of four to five strains, and those of two beta-lactam antibiotics and amikacin inhibited growth of five strains. These results suggest the potential usefulness of a combination of two beta-lactam antibiotics and amikacin or that of three beta-lactam antibiotics in treating multi-drug resistant P. aeruginosa infections.

Amikacin↗
PubMed1999

Two mRNA species encoding calcium-dependent protein kinases are differentially expressed in sexual organs of Marchantia polymorpha through alternative splicing.

In plants, calcium-dependent calmodulin-independent protein kinases (CDPKs) are the predominant calcium-regulated protein kinases and their genes are encoded by a multigene family. A CDPK gene was cloned from a liverwort, Marchantia polymorpha, which showed a high level of sequence similarities to other higher plant CDPK genes. The liverwort CDPK gene consisted of 9 exons and 8 introns. The 6th and 7th exons (Exon 6A and Exon 6B) were almost identical except for 4-amino acid substitutions, both of which coded for EF-hands in the calcium-binding domain. RT-PCR analysis revealed that two species of mature mRNA containing either Exon 6A or Exon 6B were generated from a single CDPK gene by mutually exclusive alternative splicing. Both histidine-tagged fusion proteins derived from cDNAs containing either Exon 6A or Exon 6B exhibited calcium-dependent protein kinase activity in vitro. Preferential accumulation of the mature mRNA with Exon 6A detected in male sexual organ implies possible sexual control of the ratio between the two CDPK isozymes through alternative splicing. Functions and evolution of CDPKs are discussed based on the structure and expression of the liverwort CDPK gene.

Alternative Splicing↗
PubMed1999

Promising therapy for congenital giant pigmented nevi using acellular autograft nevi-dermal matrix.

As promising new therapy for congenital giant pigmented nevi, the authors investigated the potential use of an acellular autograft nevi-dermal matrix in combination with a split-thickness skin graft. To address whether the processed acellular nevi-dermal matrix from frozen skin could be reconstituted as a viable dermal base, the authors grafted it onto full-thickness skin defects in nude rats. Fibroblast infiltration and neovascularization into the acellular nevi-dermal matrix were observed. However, because the disappearance of the residual melanotic granules of the grafted dermis took 16 weeks, the authors excised with scissors the superficial layer of the acellular nevi-dermal matrix containing a large quantity of melanin. The appearance after using this method was relatively superior even compared with the full-thickness skin graft. The success of their experimental animal model using the acellular nevi-dermal matrix covered with split-thickness skin grafts confirms the potential value for the clinical application of this treatment for congenital giant nevi.

Animals↗
PubMed1999

Crystallization and preliminary x-ray studies of flavocetin-A, a platelet glycoprotein Ib-binding protein from the habu snake venom.

Flavocetin-A (FL-A) is a platelet glycoprotein Ib-binding protein, a high molecular mass oligomer (149 kDa) of C-type lectin-like subunits alpha and beta isolated from the habu snake venom. Purified FL-A crystallized in the tetragonal space group I4 with unit-cell dimensions a = b = 121.0, c = 63.2 A. The crystals diffract to at least 2.4 A resolution. The structure has been solved by molecular replacement using the crystal structure of factors IX/X-binding protein (PDB code 1ixx) as a search model. The asymmetric unit contains one heterodimer, showing that FL-A is a novel tetradimer (alphabeta)(4) composed of four heterodimers related by a crystallographic fourfold axis.

Animals↗
PubMed1999

A selective cyclooxygenase-2 inhibitor suppresses tumor growth in nude mouse xenografted with human head and neck squamous carcinoma cells.

The anti-tumor effect of a selective cyclooxygenase (COX)-2 inhibitor, JTE-522, was examined with the human head and neck squamous cell carcinoma cell line KB. KB cells do not produce prostaglandin (PG)-E2. In vitro, JTE-522 induced an increase of G1 phase-arrested cells, suppression of platelet-derived growth factor (PDGF) production and inhibition of telomerase activity. No cytotoxic effect was detected. In vivo, the growth of the tumor xenografted into nude mice was significantly suppressed by JTE-522. Suppression of angiogenesis at the periphery of the tumor, increase of G1-arrested cells and suppression of telomerase activity were observed, together with an increase of apoptotic cell death in the tumor. Immunological enhancement did not play a role. We concluded that the anti-tumor effect of JTE-522 was caused by anti-angiogenesis action, cell cycle arrest and inhibition of telomerase activity of the tumor cells. These combined effects might induce apoptosis.

Animals↗
PubMed1999

An antioxidant, probucol, induces anti-angiogenesis and apoptosis in athymic nude mouse xenografted human head and neck squamous carcinoma cells.

Probucol is a very strong synthetic antioxidant that was been safely used for the treatment of hyperlipidemia in Japan since 1985. It has been reported that lipid oxidation products can alter growth factor production, which could influence smooth muscle cell proliferation. Oxidized low density lipoprotein can influence smooth muscle cell proliferation by enhancing the expression of platelet-derived growth factor (PDGF)-AA gene and PDGF receptor in vascular smooth muscle cell. Further, free radical reactions can cause irreversible alterations of genomic constituents during the initiation phase of carcinogenesis. Antioxidant is considered to protect lipids and low density lipoprotein (LDL) from oxidation, which potentially inhibits angiogenesis, and rapid removal of free radicals by antioxidants could have an anti-carcinogenic effect. In the present study, we investigated whether antioxidant treatment with probucol had an antitumor effect on KB cells, a human head and neck squamous carcinoma cell line. Probucol did not have any effect on KB cells in vitro, but probucol treatment of KB cells xenografts in mice had a significant antitumor effect through anti-angiogenic and apoptosis-inducing actions. These results support the idea that probucol is useful for preventing and/or treating cancer.

Animals↗
PubMed1999

Posttreatment M-protein nadir level is a significant prognostic factor associated with survival in multiple myeloma. Nagoya Myeloma Cooperative Study Group.

In the present study 142 patients with myeloma (102 with IgG M-protein and 40 with IgA) treated with either VMCP (65 patients) or MMCP (77 patients) as remission induction therapy were retrospectively analyzed. Response to treatment was evaluated in terms of a more-than-50% fall of pretreatment M-protein and the posttreatment M-protein nadir. Though significantly more patients treated with MMCP achieved partial response (PR) as compared with those treated with VMCP (P=0.019) and though patients achieving PR showed a significantly longer survival than those with less responsiveness (P=0.0091), the difference in survival curves between the two treatment groups was not significant (P=0.1871). The difference in response between the treatment groups evaluated in terms of posttreatment nadir was not significant (P=0.507). Multivariate analysis identified posttreatment M-protein nadir as a significant prognostic factor associated with survival, along with 3 other factors: sex, performance status, and hemoglobin. The lack of difference between the survival curves for patients treated with the 2 regimens despite the significantly different response rates evaluated in terms of percent fall of pretreatment M-protein levels was considered to be due to the lack of a difference in the ability to induce a deep posttreatment nadir between the regimens. Posttreatment M-protein nadir is an important prognostic factor associated with survival and should be included in the evaluation of the efficacy of chemotherapy.

Aged↗
PubMed1999

Clinical application of cultured oral epithelium for palatal wounds after palatoplasty: a preliminary report.

OBJECTIVE: Mucoperiosteal defects of the hard palate after palatoplasty scar causing scar contraction, leading to poor growth of the maxilla. The promotion of wound healing in these cases through cultured epithelial allografting has been reported. Cultured epithelial allografting was done using allogeneic cultured cells, in the hope of improving growth of maxilla. SUBJECTS AND METHODS: Clefts of the soft and hard palate (seven patients), and a cleft of the soft palate (two patients) were present. Average patient age was 1 year 4 months. Palatoplasty was done by a conventional push-back operation. Oral epithelial cells from healthy adults were cultured using 3T3 cells as the feeder layer. After 3 weeks, cultured oral mucosal epithelium was grafted on a raw surface following palatoplasty. RESULTS: The result was compared in two patients who had undergone push-back operation only. In all patients, the grafted areas underwent re-epithelialization after about 1 week and did not exhibit any clinical signs of graft rejection. Grafted areas healed completely after 2-3 weeks in all cases. CONCLUSION: Cultured epithelial allografts serve as a temporary biological dressing, and accelerate epithelialization and wound healing. Allografting by cultured oral epithelium has proved to be a very useful therapeutic modality in palatoplasty, as well as effective augmentation materials in cases of oral mucosal defects.

3T3 Cells↗
PubMed1999

Characteristics of two forms of alpha-amylases and structural implication.

Complete (Ba-L) and truncated (Ba-S) forms of alpha-amylases from Bacillus subtilis X-23 were purified, and the amino- and carboxyl-terminal amino acid sequences of Ba-L and Ba-S were determined. The amino acid sequence deduced from the nucleotide sequence of the alpha-amylase gene indicated that Ba-S was produced from Ba-L by truncation of the 186 amino acid residues at the carboxyl-terminal region. The results of genomic Southern analysis and Western analysis suggested that the two enzymes originated from the same alpha-amylase gene and that truncation of Ba-L to Ba-S occurred during the cultivation of B. subtilis X-23 cells. Although the primary structure of Ba-S was approximately 28% shorter than that of Ba-L, the two enzyme forms had the same enzymatic characteristics (molar catalytic activity, amylolytic pattern, transglycosylation ability, effect of pH on stability and activity, optimum temperature, and raw starch-binding ability), except that the thermal stability of Ba-S was higher than that of Ba-L. An analysis of the secondary structure as well as the predicted three-dimensional structure of Ba-S showed that Ba-S retained all of the necessary domains (domains A, B, and C) which were most likely to be required for functionality as alpha-amylase.

Amino Acid Sequence↗
PubMed1999

[Analysis of elderly patients, aged 60 years old or over, with acute lymphoblastic leukemia].

In order to obtain the realistic background information on clinical features, and the present status of treatment and outcome in elderly patients with acute lymphoblastic leukemia (ALL), we carried out random survey of patients with ALL aged 60 or over who had been admitted to 13 general hospitals in the Nagoya region from January 1990 through December 1995. Among the 20 cases collected, ages ranged from 60 to 88 (median age 68), and the male to female ratio was 11:9. Nineteen cases were L2 subtype in FAB classification. Among 17 patients, 13 had B cell series surface phenotypes (76%), 2 had T cell series (12%), one had stem cell type (6%) and one had an undetermined phenotype (6%). Ph chromosomes were detected in 4 cases among 15 analyzed (27%), whereas 5 were found to have no chromosomal abnormality. Half of the patients had some concurrent disease at diagnosis, including two with treatment-limiting complications. Common induction regimens were the combination of adriamycin (ADM) + vincristine (VCR) + cyclophosphamide (CPM) + mitoxdn trone + L-asparaginase [4 patients]. ADM + VCR + PSL [4 patients]. VCR + PSL [4 patients] and others [8 patients]. The overall remission rate was 55.0% (11/20) without any significant difference according to age. The median survival time (MST) for all cases was 205 days. (1-year survival rate:17.9%, 2-year survival rate:10.8%). There was no significant difference in survival times among patients with the Ph chromosome, those with other chromosomal abnormalities and those without them. All the patients aged 75 or over were treated with attenuated induction therapy, and they had a shorter survival than those aged less than 75, but with no statistical significance [MST:121 days versus 276 days, p = 0.307 (generalized Wilcoxon test)].

Aged↗
PubMed1999

[Tracheobronchial stents for management of airway stenosis].

Airway prostheses provide an excellent method for providing relief for patients with malignant or benign stenoses. Two types of prostheses are currently available: rigid silicone stents and metallic expandable stents. Silicone stents have been proven to be well tolerated, nonreactive, and easily removable during several decades of clinical application. However, they impair the drainage of sputum because of interrupted ciliary movement. Subsequently, retained secretions within the stent lumen can be obstructive. In addition, dislodgment frequently occurs because of their rigidity. The advantages of metallic expandable stents are as follows: 1) they can be inserted under local anesthesia with relative simplicity: 2) they do not impair the drainage of sputum: 3) ventilation is usually possible even if the metallic mesh stent covers another bronchus: and 4) their flexibility allows them to bend and conform better than rigid stents to tortuous airway stenoses. The disadvantages of metallic stents are: 1) tumor or granulation ingrowth can occur because of their porosity: 2) removal is difficult: and 3) there is limited experience with their use because they have only recently been employed for airway stenoses.

Bronchial Diseases↗
PubMed1999

Acute myeloid leukemia in the elderly:--159 Nagoya case studies--Nagoya Cooperative Study Group for Elderly Leukemia.

To obtain background information on elderly acute myeloid leukemia (AML), unselected data covering 159 patients aged 60 years or over with AML from 14 hospitals in Nagoya, Japan was analyzed retrospectively. Among these patients, 119 had de novo acute AML, 32 had AML which evolved from myelodysplastic syndrome (MDS-AML), and 8 had other types of leukemia. The survey showed that MDS-AML tended to be more prevalent in patients aged 70 years and older and that MDS-AML showed a significantly more severe degree of leukopenia and anemia than de novo AML. MDS-AML also showed a significantly lower complete remission (CR) rate than that of de novo AML [6.9% (2/29) vs 58.3% (67/11), P < 0.01] and significantly shorter survival times than those of de novo AML [median: 3.6 months vs 9.6 months, P < 0.01 (generalized Wilcoxon test; GW]. In de novo AML, the proportion of patients treated with conventional therapy (CT group) decreased significantly, and that of those with attenuated therapy (AT group) increased significantly as age elevated (P < 0.01). The CT group showed a significantly higher CR rate (65.4% vs 41.2%, P < 0.05) and a significantly longer survival period than those of the AT group [median: 11.6 months vs 4.8 months, P < 0.05 (GW)]. Overall survival rates of the older age groups became significantly shorter with aging [P < 0.01 (GW)].

Acute Disease↗
PubMed1998

The Dictyostelium developmental cDNA project: generation and analysis of expressed sequence tags from the first-finger stage of development.

In an effort to identify and characterize genes expressed during multicellular development ill Dictyostelium, we have undertaken a cDNA sequencing project. Using size-fractionated subsets of cDNA from the first finger stage, two sets of gridded libraries were constructed for cDNA sequencing. One, library S, consisting of 9984 clones, carries relatively short inserts, and the other, library L, which consists of 8448 clones, has longer inserts. We sequenced all the selected clones in library S from their 3'-ends, and this generated 3093 non-redundant, expressed sequence tags (ESTs). Among them, 246 ESTs hit known Dictyostelium genes and 910 showed significant similarity to genes of Dictyostelium and other organisms. For library L, 1132 clones were randomly sequenced and 471 non-redundant ESTs were obtained. In combination, the ESTs from the two libraries represent approximately 40% of genes expressed in late development, assuming that the non-redundant ESTs correspond to independent genes. They will provide a useful resource for investigating the genetic networks that regulate multicellular development of this organism.

Animals↗
PubMed1998

Coagulation factor X-binding protein from Deinagkistrodon acutus venom is a Gla domain-binding protein.

Factor IX/factor X-binding protein (IX/X-bp) is an anticoagulant isolated from the venom of Trimeresurus flavoviridis (habu snake) and binds predominantly to factor IX. In this study, we isolated IX/X-bp-like proteins from the venom of Deinagkistrodon acutus (hundred pace snake) with binding characteristics different from those of IX/X-bp. The complete amino acid sequence and binding characteristics of the main anticoagulant protein, named X-bp, were investigated. The concentrations of X-bp at half-maximal binding to solid-phase factors X and IX were 0.4 and 3 nM, respectively. The binding of X-bp to solid-phase factor X was inhibited by 50% by 6- and 9-fold excess concentrations of factor X and Gla domain (GD) peptide 1-44, respectively, but was not influenced by GD peptide 1-41 and Gla domainless factor X. X-bp bound two Ca2+ ions per molecule with Kd values of 16 +/- 0.7 (mean +/- SE, n = 6) and 103 +/- 10 microM. X-bp was a heterodimer of C-type lectin-like subunits. The 16 kDa chain (A chain) consisted of 129 amino acid residues and was 68% identical to the sequence of the A chain of IX/X-bp. The 15 kDa chain (B chain) consisted of 123 amino acid residues and was 87% identical to IX/X-bp. Three-dimensional model construction from the known fold of IX/X-bp showed that amino acid residues different from those of IX/X-bp are mostly on the molecular surface. Some of these are concentrated on a part of the concave surface which is considered to be the coagulation factor-binding site, presumably acting as a discriminator for ligand binding. These results indicated that X-bp isolated from D. acutus venom was a GD-binding protein, and the C-terminal region of GD peptide was critical for folding of the peptide.

1-Carboxyglutamic Acid↗
PubMed1998

Neurotrophic action of lipocortin 1 derived from astrocytes on cultured rat cortical neurons.

The lipocortins are a family of structurally related proteins, namely an annexin family, that exerts a variety of cellular functions through Ca2+-dependent binding to phospholipase A2 [EC 3.1. 1.4], including a crucial role in the central nervous system (CNS) such as antipyrogenic, thermoregulatory and neuroprotective agents in vivo. To elucidate the paradigm of lipocortin 1 functions in the CNS, we have first demonstrated (1) the induction and subsequent extracellular secretion of LC1 by glucocorticoid in cultured rat astrocytes, and (2) neurotrophic activities (survival-promoting, neuritogenic and synaptogenic actions on rat cortical neurons) of recombinant LC1. Time-and dose-dependent experiments of a synthetic glucocorticoid, dexamethasone (DEX), on rat cortical astrocytes in culture revealed that the expression of the intracellular LC1 mRNA and protein were significantly augmented by DEX (1 microM). In addition, DEX evoked an extracellular secretion of LC1 without its cytotoxic effects. Furthermore, the recombinant LC1 appeared to promote not only the survival and neurite outgrowth but also the synaptogenesis of embryonal rat cortical neurons. These results suggest that LC1 induced and selectively released from astrocytes by either endogenously or exogenously introduced glucocorticoids may play a specific and essential role on development and regeneration of the central nervous system.

Animals↗