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Biomedical subjects

M Wada

Publications and source records attributed to M Wada.

At least 235 records · Page 13Linked to original sources
PubMed1998

Isolation of a novel human canalicular multispecific organic anion transporter, cMOAT2/MRP3, and its expression in cisplatin-resistant cancer cells with decreased ATP-dependent drug transport.

The human multidrug resistance protein (MRP) gene encodes a membrane protein involved in the ATP-dependent transport of hydrophobic compounds. We previously isolated a canalicular multispecific organic anion transporter, cMOAT1/MRP2, that belongs to the ATP binding cassette (ABC) superfamily, which is specifically expressed in liver, and cMOAT1/MRP2 is responsible for the defects in hyperbilirubinemia II/Dubin-Johnson syndrome. In this study, we isolated a new cDNA of the ABC superfamily designated cMOAT2/MRP3 that is homologous to human MRP1 and cMOAT1/MRP2: cMOAT2/MRP3 is 56% identical to MRP1 and 45% identical to cMOAT1/MRP2, respectively. Fluorescence in situ hybridization demonstrated the chromosomal locus of this gene on chromosome 17q22. The human cMOAT2 cDNA hybridized to a 6.5-kb mRNA that was mainly expressed in liver and to a lesser extent in colon, small intestine, and prostate. The cMOAT2/MRP3 gene was not overexpressed in cisplatin-resistant cell lines with increased ATP-dependent transport of cisplatin over their parental counterparts derived from human head and neck cancer and human prostatic cancer cell lines. The human cMOAT2/MRP3, a novel member of the ABC superfamily, may function as a membrane transporter in liver, colon, and prostate.

Adenosine Triphosphate↗
PubMed1998

Molecular maturation and functional expression of mouse polymeric immunoglobulin receptor.

Mouse polymeric immunoglobulin receptor (pIgR) cDNA was stably introduced into a hamster-derived fibroblastic cell line, Chinese hamster ovary (CHO) cell, by the calcium phosphate method. Surface expression of pIgR was detected by immunostaining and FACS analysis. The immunoprecipitated products of cell lysates revealed that the molecular mass of the most mature form of pIgR was approximately 120 kDa. Western blotting and metabolic labeling experiments followed by immunoprecipitation with an anti-mouse secretory component (SC) Ab demonstrated the existence of a 110 kDa immature form of pIgR. The reason for the existence of two forms of pIgR molecule was examined by conducting pulse-chase experiments which revealed the pIgR underwent molecular maturation. During this process, the 110 kDa form of pIgR was converted into a 120 kDa form by glycosylation. Moreover, tunicamycin treatment revealed the core form of pIgR had a molecular mass of approximately 100 kDa. The pIgR expressed on the surface of the transfectant could specifically bind and take up mouse polymeric IgA (MOPC 315), suggesting that, at least in this mouse system, cell type-specific molecules are not necessary for surface pIgR expression and polymeric immunoglobulin (pIg) binding and uptake.

Animals↗
PubMed1998

A new Drosophila ultraviolet light-damaged DNA recognition endonuclease that selectively nicks a (6-4) photoproduct site.

We have previously described the purification of an ultraviolet light (UV) damage-specific DNA-binding protein from Drosophila melanogaster, designated D-DDB P1 [Nucleic Acids Res., 23 (1995) 2600-2607]. Here, we obtained highly purified D-DDB P1 from Drosophila Kc cells, and we found that D-DDB P1 is also a nuclease. D-DDB P1 can selectively bind to pyrimidine (6-4) pyrimidone photoproducts, and in the presence of Mg++, D-DDB P1 can catalyze an incision immediately on the 3' and 5' sides of the (6-4) photoproduct site.

Animals↗
PubMed1998

Localization of 67 exons on a YAC contig spanning 1.5 Mb around the multidrug resistance gene region of human chromosome 7q21.1.

A contig of 21 nonchimeric yeast artificial chromosomes (YACs) was previously assembled across 1.5 Mb of the multidrug resistance (MDR) gene (PGY1 and PGY3) region of human chromosome 7q21.1. This region of the human genome has now been subjected to exon amplification to detect the presence of additional genes. Exon trapping was performed directly on the YACs. Sixty-seven gene fragments were isolated and characterized by sequence analysis and comparison with public databases. The localization of these exons in the 1.5-Mb region was determined by hybridization to YAC clones, and they were localized in 11 subregions of YAC contigs. The exon collection includes 21 exons that were identical to known cDNA sequences of PGY1, PGY3, sorcin (SRI), the cDNA similar to the delta subunit of the human amiloride-sensitive Na- channel (SCNED), and 4 cDNAs with unknown function; 43 exons that showed homology/similarity to known cDNA sequences of mouse DMP1, rat COT, mouse and human NADHD, human MDC, 3 cDNAs encoding possible membrane proteins, and 21 other cDNAs; and 3 exons that shared no homology/similarity with any sequence in public databases. The nucleotide sequences of all the PGY1 and PGY3 exons were identical to the corresponding cDNA sequences previously determined, and these exons were localized to the expected positions on the appropriate YAC clones. No other member of the MDR gene family thus appeared to be present in the 1.5-Mb region. The integrated physical and exon maps should prove valuable for both fine mapping and determination of a complete gene map of this segment of the genome.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1998

Direct involvement of the Y-box binding protein YB-1 in genotoxic stress-induced activation of the human multidrug resistance 1 gene.

The human multidrug resistance 1 (MDR1) gene encoding P-glycoprotein is often overexpressed in various human tumors after chemotherapy. During treatment with various chemotherapeutic agents, the MDR1 gene is activated at the transcriptional level and/or amplified, resulting in overexpression. Our previous studies demonstrated that an inverted CCAAT box (Y-box) might be a critical cis-regulatory element regulating UV or drug-induced MDR1 gene expression. We have now established various cell lines from human head and neck cancer KB cells which were stably transfected with the chloramphenicol acetyltransferase (CAT) reporter gene driven by various MDR1 promoter deletion constructs. Transient transfection of antisense YB-1 expression constructs resulted in a decrease of both YB-1 protein levels and DNA binding activity to the inverted CCAAT box, as determined by Western blot and gel mobility shift assays. The limited expression and binding activity due to expression of antisense YB-1 constructs were also observed when cells were treated with UV. CAT activity of constructs containing the Y-box was enhanced after treatment with UV irradiation as well as genotoxic agents such as cisplatin and etoposide. Moreover, this activation was reduced by 50-80% by transfection of antisense YB-1 expression constructs. In contrast, transfection of antisense YB-1 expression constructs had no effect on CAT activity driven by MDR1 promoter constructs not containing the Y-box. These data indicate that YB-1 is directly involved in MDR1 gene activation in response to genotoxic stress.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Interaction of rat lin-10 with brain-enriched F-actin-binding protein, neurabin-II/spinophilin.

We have recently isolated a rat homologue of the Caenorrhabditis elegans lin-10 product. Although rat lin-10 is expressed in the cytosol and membrane fractions of various tissues, it is distributed only in the membrane fraction in brain where it is enriched in the synaptic plasma membrane and postsynaptic density fractions. We have isolated here a rat lin-10-interacting protein from rat brain and identified it to be neurabin-II/spinophilin, which has recently been isolated as a protein interacting with protein phosphatase I and F-actin. Neurabin-II/spinophilin is ubiquitously expressed but enriched in brain, especially in the synaptic plasma membrane and postsynaptic density fractions. We discuss the physiological significance of the interaction of rat lin-10 with neurabin-II/spinophilin.

Actins↗
PubMed1998

Involvement of matrix metalloproteinase-2 activity in invasion and metastasis of pancreatic carcinoma.

BACKGROUND: Activation of matrix metalloproteinase-2 (MMP-2) has been implicated in the progression, invasion, and metastasis of various cancers, but little information is available with regard to its role in pancreatic carcinoma with poor prognosis. METHODS: Gelatin zymography was used for the detection of latent and activated forms of MMP-2 and MMP-9 in 13 normal pancreatic tissue specimens, 14 chronic pancreatitis tissue specimens, and 33 pancreatic carcinoma tissue specimens. The gelatinase activity was quantified by densitometer, and the 66-kilodalton (kDa)/(66-kDa + 72-kDa) ratio was calculated as the MMP-2 activation ratio. Western blot analysis was performed to confirm the zymographic profile. RESULTS: Latent forms of MMP-2 and MMP-9 were detected in all samples of pancreatic carcinoma, chronic pancreatitis, and normal pancreatic tissue. The expression rate of the MMP-2 activated form in pancreatic carcinoma tissue specimens was 100% (33 of 33) but that of MMP-9 was 21%. The MMP-2 activation ratio in pancreatic carcinoma tissue specimens was significantly higher than that of chronic pancreatitis and normal pancreatic tissue specimens. The MMP-2 activation ratio in pT3 tumors was significantly higher than that in pT1 tumors. The MMP-2 activation ratio also was significantly higher in pancreatic carcinoma specimens with histologically positive regional lymph node metastasis and distant metastasis than those without metastasis. The MMP-2 activation ratio observed in patients who developed postresection recurrence within 6 months was significantly higher than that in patients without recurrence at 6 months. CONCLUSIONS: The results of the current study indicate that MMP-2 activation plays a significant role in tumor invasion and metastasis in pancreatic carcinoma.

Adenocarcinoma, Mucinous↗
PubMed1998

Neurabin-II/spinophilin. An actin filament-binding protein with one pdz domain localized at cadherin-based cell-cell adhesion sites.

In a preceding paper, we reported a novel actin filament (F-actin)-binding protein, named neurabin, which was specifically expressed in neural tissue and implicated in neurite formation. We purified from rat brain another F-actin-binding protein, which had a domain organization similar to that of neurabin but was ubiquitously expressed, and named it neurabin-II. The original neurabin, renamed neurabin-I, had 1095 amino acids and a calculated Mr of 122,729, whereas neurabin-II had 817 amino acids and a calculated Mr of 89, 642. Both neurabin-I and -II had one F-actin-binding domain at the N-terminal region, one PDZ domain at the middle region, a domain known to interact with transmembrane proteins, and domains predicted to form coiled-coil structures at the C-terminal region. Both neurabin-I and -II bound along the sides of F-actin and showed F-actin-cross-linking activity. The subcellular distribution analysis indicated that neurabin-II was enriched at the postsynaptic density fraction in rat brain and the adherens junction fraction in rat liver. Immunofluorescence microscopic analysis revealed that neurabin-II was highly concentrated at the synapse in primary cultured rat hippocampal neurons and at the cadherin-based cell-cell adhesion sites in Madin-Darby canine kidney cells. Neurabin-II turned out to be the same as a recently reported protein phosphatase 1-binding protein named spinophilin. These results suggest that neurabin-II/spinophilin plays an important role in linking the actin cytoskeleton to the plasma membrane.

Actins↗
PubMed1998

Genomic organization of the human Y-box protein (YB-1) gene.

The human Y-box protein (YB-1) is a member of a family of DNA-binding proteins containing a highly conserved cold shock domain. The genomic organization of the human YB-1 gene was determined from five overlapping genomic clones that encompassed all exons of the gene. Sequence analysis of these clones revealed that human YB-1 spans approximately 19 kb of genomic DNA and contains eight exons. The cold shock domain is encoded by exons 1-5. Both exon-splitting and codon-splitting in the region of the gene encoding the cold shock domain are similar to those in the corresponding region of another Y-box binding protein, dbpA. Exon-intron structures and nucleotide sequences of the regions encoding the N-terminal and C-terminal domains of the two proteins differ markedly between YB-1 and dbpA. These observations suggest that YB-1 and dbpA arose by duplication of a common ancestral gene encoding all these domains.

Base Sequence↗
PubMed1998

Parathyroid hormone suppression by 22-oxacalcitriol in the severe parathyroid hyperplasia.

The suppression of parathyroid hormone (PTH) secretion by the administration of 1,25-dihydroxyvitamin D [1,25(OH)2D3] and 22-oxacalcitriol (OCT) was evaluated in nude mice transplanted with human hyperplastic parathyroid tissue. The parathyroid tissue was obtained for transplantation from a patient with severe secondary hyperparathyroidism who had undergone a parathyroidectomy. Tissue specimens were transplanted into the gluteus muscle of female nude mice. Animals were divided into two groups; one group was fed a normal diet, and the other group was fed a low calcium diet during the administration of OCT and 1,25(OH)2D3. OCT and 1,25(OH)2D3 were intraperitoneally administered two times every week, for a total of eight times. Serum calcium and phosphate levels were significantly higher in the mouse administered 1,25(OH)2D3 than in the mouse administered OCT. Serum alkaline phosphatase activity was elevated similarly in the mouse administered either OCT or 1,25(OH)2D3. OCT strongly suppressed human PTH secretion from the graft in mice with normal serum calcium levels as did 1,25(OH)2D3. However, human PTH secretion from the graft was stimulated by the administration of a low-calcium diet, despite OCT and 1,25(OH)2D3 administration. In summary, OCT and 1,25(OH)2D3 suppress PTH secretion even from severe secondary hyperplastic parathyroid tissue only in mice with normal or high calcium serum levels.

Alkaline Phosphatase↗
PubMed1998

Isolation and characterization of homologues of plant blue-light photoreceptor (cryptochrome) genes from the fern Adiantum capillus-veneris.

Many blue-light mediated physiological responses have been studied in the fern Adiantum capillus-veneris. We have isolated genomic clones encoding sequences similar to those encoding blue-light photoreceptors (cryptochromes) in higher plants using the Arabidopsis CRY1 cDNA as a probe, and these positive clones fall into five independent groups. Using RACE procedures, we obtained full-length cDNA sequences for three of these five groups. The deduced amino acid sequences include the photolyase-homologous domain in the N-terminal half, and they also contain a C-terminal extension of about 200 amino acids in length. These structural features indicate that the genes indeed encode Adiantum cryptochromes and represent a small gene family having at least three members.

Amino Acid Sequence↗
PubMed1998

Pioglitazone enhances splanchnic glucose uptake as well as peripheral glucose uptake in non-insulin-dependent diabetes mellitus. AD-4833 Clamp-OGL Study Group.

To evaluate the effect of pioglitazone on insulin resistance in non-insulin-dependent diabetes mellitus (NIDDM) patients, a double-blind placebo-controlled trial was carried out with 30 NIDDM patients. Twenty-one subjects, three on diet alone and 18 on sulfonylurea (SU), orally received 30 mg pioglitazone once daily for 12 weeks. Nine subjects, one on diet alone and eight on SU, received a matching placebo once daily for 12 weeks. Euglycemic (5.2 mmol/l) hyperinsulinemic (1200 pmol/l) clamp combined with an oral glucose load (OGL) was performed before and after 3-month treatment with pioglitazone or placebo to determine insulin-stimulated glucose disposal and splanchnic glucose uptake (SGU). No significant differences existed in the patients' characteristics, including age and body mass index, between the two study groups. The pioglitazone treatment increased the mean glucose infusion rate (GIR) prior to OGL from 8.2 +/- 2.2 to 9.2 +/- 2.0 mg/kg.min (mean +/- SD, P = 0.003) and increased the SGU rate from 28.5 +/- 19.4 to 59.4 +/- 27.1% (P = 0.010). The placebo treatment produced no significant changes in either GIR or SGU after treatment. A significant difference (P = 0.042) was observed in change of SGU between the pioglitazone and placebo treatment groups. In conclusion, the results indicate that pioglitazone is effective for ameliorating insulin resistance in NIDDM by enhancing SGU as well as peripheral glucose uptake.

Blood Glucose↗
PubMed1998

Prosthetic knee Candida parapsilosis infection.

We report a 77-year-old man who developed Candida parapsilosis infection following total knee arthroplasty. Knee joint effusion was noted 2 weeks after surgery, and repeated cultures of aspirated fluid established the diagnosis of Candida parapsilosis infection 4 weeks after surgery. Treatment consisted of debridement and lavage of the involved joint together with continuous irrigation with fluconazole for 4 weeks, followed by oral fluconazole for another 6 months. At 3 years follow-up, the patient was doing well and radiological examination of the affected knee showed a firm attachment of the prosthesis. We suggest that early identification of the causative organism followed by continuous irrigation and use of appropriate antifungal medication may prevent joint instability and spares the removal of the prosthesis.

Aged↗
PubMed1998

Expression of two angiogenic factors, vascular endothelial growth factor and platelet-derived endothelial cell growth factor in human pancreatic cancer, and its relationship to angiogenesis.

Tumour angiogenesis, as assayed by microvessel density (MVD), and the expression of vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PD-ECGF) have become established as important prognostic indicators for many tumour types. In this study, MVD and the expression of VEGF and PD-ECGF were examined by immunohistochemical staining of 50 pancreatic cancer tissues, and the relationships between either MVD or the expression of these two angiogenic factors and the clinicopathological features, including survival, were analysed. The expression of VEGF and PD-ECGF proteins were confirmed by Western blot analysis and VEGF mRNA isoforms were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) in five pancreatic cancer cell lines. Twenty-eight (56%) of 50 pancreatic cancers were positive for VEGF protein in cancer cells, and 16 (32%) showed strong PD-ECGF staining in cancer and infiltrating cells. VEGF121 and VEGF165 were identified as the predominant species produced in pancreatic cancer cells. The overexpression of VEGF and PD-ECGF protein significantly correlated with high MVD (P = 0.002, 0.044, respectively). Advanced stage of disease was significantly more frequent in patients with high MVD (P = 0.025). No significant association was found between the expression of VEGF or PD-ECGF and clinicopathological features, except for tumour histology. The expression of PD-ECGF correlated with poor survival (P = 0.011), but MVD and VEGF expression were not found to be useful for the prediction of overall survival. This study suggests that VEGF and PD-ECGF may play an important role in tumour angiogenesis, and that PD-ECGF expression seems to be useful for establishing prognoses for pancreatic cancer.

Blotting, Western↗
PubMed1998

Dried green leaf powders of Jew's mellow (Corchorus), persimmon (Diosphyros kaki) and sweet potato (Ipomoea batatas poir) lower hepatic cholesterol concentration and increase fecal bile acid excretion in rats fed a cholesterol-free diet.

A cholesterol-free diet containing dried powder of Jew's mellow leaves, persimmon leaves or sweet potato leaves respectively at 5% level as dietary fiber was fed to male Sprague-Dawley rats for about one month. The experiment was conducted twice except for sweet potato leaves. In the groups fed the diet mixed with powders of any of the three different dried green leaves, the hepatic cholesterol concentration significantly decreased. Such lowering was not observed in serum cholesterol concentration compared with the control (cellulose) group. A significant increase in fecal weight was observed in all the groups fed the green leaf samples. All the dried green leaves increased fecal excretion of bile acids per gram or per day compared with the control group in both experiments, but only the dried Jew's mellow leaves showed an increased excretion of neutral sterols. These results suggest that lowering of hepatic cholesterol by powdered green leaves is not necessarily due to the same factor, but to the increased fecal excretion of bile acids due to inhibited enterohepatic circulation in animals given these samples.

Animals↗
PubMed1998

Cervical myeloradiculopathy with entrapment neuropathy: a study based on the double-crush concept.

In an attempt to formulate a standardised approach to the diagnosis and management of patients with the double-crush syndrome, we reviewed 65 surgical cases (39 men and 26 women) with cervical myeloradiculopathy associated with entrapment neuropathy in the arm by examining the clinical features, results of nerve conduction velocity studies and distribution of the vertebral levels of compression. Fifty-three patients (average age, 43 years) presented with a carpal tunnel syndrome at the wrist and cervical lesions (41 with spondylosis and 12 with ossified posterior longitudinal ligament), while 12 had a cubital tunnel syndrome at the elbow with cervical lesions (eight with spondylosis and four with ossification of the posterior longitudinal ligament). In the former group, the lesions were found mostly at C5-6 and C6-7 levels, while in the latter group involvement of C6-7 was frequently observed. Two patients in each group required additional cervical decompression after carpal or cubital tunnel release. A retrospective review of our patients suggested that it is reasonable to pursue an accurate diagnosis followed by treatment based on individual neurological and electrophysiological findings, but taking into consideration the significant level of physical impairment associated with cord compromise, we believe that it may be reasonable to perform a cervical decompression rather than peripheral nerve release in such cases. Our findings suggest that one should be aware of a double-crush during examination of patients complaining of neck and hand problems.

Adult↗
PubMed1998

Solitary plasmacytoma of the spine associated with neurological complications.

We report eight patients with a solitary plasmacytoma of the spine associated with neurological complications. The patients included five men and three women with an average age at presentation of 59 years (range, 47 to 73 years). The tumour was confined to the thoracic spine in six cases, cervical spine in one and lumbar spine in one. Duration of symptoms ranged from 2.5 to 22 months. Treatment consisted of a combination of radiotherapy, melphalan and surgery. One patient progressed to multiple myeloma 7 years after surgery. Surgical treatment (anterior surgery in three cases and posterior surgery in five) produced neurological improvement in all patients. We stress the importance of an early diagnosis followed by appropriate treatment including surgery for this clinical entity and long-term follow-up to detect a disseminated disease.

Aged↗