Biomedical subjects

M Matsushima

Publications and source records attributed to M Matsushima.

At least 19 recordsLinked to original sources

PubMed1997

Geographic variation in mortality among individuals with youth-onset diabetes mellitus across the world. DERI Mortality Study Group. Diabetes Epidemiology Research International.

The aim of this study was to evaluate the geographic variation in mortality among individuals with youth-onset insulin-dependent diabetes mellitus (IDDM) across the world. The study was based on the currently available IDDM incidence and mortality data. Mortality data for diabetes in the 0-24 year age group were obtained from the World Health Organization (WHO) statistics. The mortality rates were adjusted for the frequency of occurrence of IDDM and dividing the mortality rates by the IDDM incidence rates which were obtained from the WHO DiaMond project. There was a more than 10-fold geographic variation in mortality between the developed countries and Eastern European populations. The areas with the highest mortality rates were located in Japan, Eastern Europe and Russia. The areas having the best outcome associated with IDDM were Northern Europe, Central Europe, and Canada. An ecological study demonstrated a relationship between the incidence-adjusted mortality (estimated case-fatality) with IDDM incidence itself (Spearman's correlation coefficient = 0.45) as well as infant mortality and life expectancy at birth. These data demonstrated the possibility of an enormous geographic variation in mortality of youth-onset diabetic patients even in developed countries. It is important to note that these excess deaths are potentially preventable. The ecological study also suggested that the mortality differences may be in part related to overall and diabetes related care.

Adolescent↗

PubMed1997

Expression of transforming growth factor-beta mRNA in experimental choroidal neovascularization.

PURPOSE: Transforming growth factor beta (TGF-beta) is a multifunctional cytokine that modulates biological events as diverse as wound healing and angiogenesis and which may be important in the pathogenesis of choroidal neovascularization. We investigated the mRNA expression of TGF-beta isoforms in a model of experimental choroidal neovascularization induced by krypton-laser photocoagulation. METHODS: Rat TGF-beta 1, mouse TGF-beta 2 or TGF-beta 3 cDNAs was inserted into the pBluescript vector to prepare antisense and sense riboprobes. Intense laser burns were applied to the posterior poles of the eyes of pigmented rats according to a protocol described for producing choroidal neovascularization in these animals. At intervals up to 4 weeks after photocoagulation, the eyes were obtained and cut into thin sections. The sections were subjected to in situ hybridization with digoxigenin (DIG)-labeled single-strand riboprobes synthesized from each TGF-beta cDNA. RESULTS: In normal adult rat retinas and choroids, TGF-beta 1 mRNA was found only in cells of the ganglion cell layer, TGF-beta 2 mRNA was found in cells of the ganglion cell layer and choriocapillaris endothelium, whereas TGF-beta 3 mRNA was not detected at all. During the process of neovascularization, TGF-beta 1 and TGF-beta 2 mRNAs (the latter being expressed more prominently) were detected in retinal pigment epithelial cells, fibroblast-like cells and the endothelium of the neovascular region. TGF-beta 2 was the predominant isoform of TGF-beta, and its expression was especially strong in the endothelium of the choroidal neovascularization at 2 weeks. However, TGF-beta mRNAs was decreased in cells 4 weeks after photocoagulation. CONCLUSIONS: Our findings suggest that TGF-beta may act in the retina as a neurotrophic agent, since TGF-beta 1 is normally transcribed in ganglion cells and TGF-beta 2 is also transcribed in ganglion cells and choriocapillaris endothelium. TGF-beta 1 and TGF-beta 2 mRNA expression were increased in photocoagulated lesions from 3 days to 2 weeks after laser treatment. Therefore, it is likely that TGF-beta acts as a mediator of the neovascularization process.

Animals↗

PubMed1996

Definition of a commonly deleted region in ovarian cancers to a 300-kb segment of chromosome 6q27.

Allelic deletions of chromosome 6q that occur frequently in ovarian cancers imply the presence of a putative tumor suppressor gene in this chromosomal vicinity. We analyzed DNA from 32 patients with ovarian carcinomas for loss of heterozygosity at loci on the distal portion of chromosome 6q and constructed a detailed deletion map. The map indicated a commonly deleted region between loci D6S149 (defined by CI6-24) and A2, which are estimated to be 300 kb apart on the basis of our cosmid contig map. By means of exon trapping, we found that the human AF-6 gene, which is disrupted in acute myeloid leukemia cells that carry a (6;11)(q27;q23) translocation, is located within the commonly deleted region. Subsequent screening of the AF-6 gene in ovarian carcinomas revealed no mutations. However, our mapping results, which narrowed the region containing the putative tumor suppressor gene to a 300-kb segment of 6q27, will facilitate further efforts to identify a gene associated with ovarian cancer.

Blotting, Southern↗

PubMed1996

Crystal structure of PotD, the primary receptor of the polyamine transport system in Escherichia coli.

PotD protein is a periplasmic binding protein and the primary receptor of the polyamine transport system, which regulates the polyamine content in Escherichia coli. The crystal structure of PotD in complex with spermidine has been solved at 2.5-A resolution. The PotD protein consists of two domains with an alternating beta-alpha-beta topology. The polyamine binding site is in a central cleft lying in the interface between the domains. In the cleft, four acidic residues recognize the three positively charged nitrogen atoms of spermidine, while five aromatic side chains anchor the methylene backbone by van der Waals interactions. The overall fold of PotD is similar to that of other periplasmic binding proteins, and in particular to the maltodextrin-binding protein from E. coli, despite the fact that sequence identity is as low as 20%. The comparison of the PotD structure with the two maltodextrin-binding protein structures, determined in the presence and absence of the substrate, suggests that spermidine binding rearranges the relative orientation of the PotD domains to create a more compact structure.

ATP-Binding Cassette Transporters↗

PubMed1996

Complementary DNA cloning and sequencing of rat enteropeptidase and tissue distribution of its mRNA.

A cDNA clone encoding enteropeptidase (EC 3.4.21.9), a key enzyme for the conversion of trypsinogen to trypsin, was isolated from a rat duodenal mucosa cDNA library. Sequences of the 3585 base pair clone predicted that enteropeptidase is synthesized as a single-chain precursor form, proenteropeptidase, consisting of 1058 amino acid residues with an internal signal sequence (51 residues) and is then processed into the mature enzyme consisting of three different peptide chains, i.e., mini, light and heavy chains, not the previously reported two-chain enzyme. The structure of enteropeptidase is relatively conserved among different species and the rat enteropeptidase is 24 and 39 amino acids longer than the porcine and human ones, respectively. Northern blot analysis of rNAs from normal rat tissues revealed that the enteropeptidase mRNA of around 4.4 kb in size was expressed only in the duodenal mucosa, and high proteolytic activity of the enzyme was detected in the proximal small intestine. Additional analysis of the RNAs by RT-PCR revealed that a low level of the mRNA was also expressed in the other parts of the small intestine, i.e., jejunum and ileum. These results indicate that the biosynthesis of enteropeptidase takes place mainly in the proximal small intestine, the duodenum, and the importance of the region in the physiology of intestinal protein digestion regulated by the enzyme is suggested. Furthermore a faint signal of the mRNA was also detected in the stomach, colon and brain in which the existence of trypsin-like serine proteases were reported. The significance of the low level expression of the gene is unclear, but the potential peptide-processing function of the enzyme in these tissues is also suggested.

Amino Acid Sequence↗

PubMed1996

The 1.8-A X-ray structure of the Escherichia coli PotD protein complexed with spermidine and the mechanism of polyamine binding.

The PotD protein from Escherichia coli is one of the components of the polyamine transport system present in the periplasm. This component specifically binds either spermidine or putrescine. The crystal structure of the E. coli PotD protein complexed with spermidine was solved at 1.8 A resolution and revealed the detailed substrate-binding mechanism. The structure provided the detailed conformation of the bound spermidine. Furthermore, a water molecule was clearly identified in the binding site lying between the amino-terminal domain and carboxyl-terminal domain. Through this water molecule, the bound spermidine molecule forms two hydrogen bonds with Thr 35 and Ser 211. Another periplasmic component of polyamine transport, the PotF protein, exhibits 35% sequence identity with the PotD protein, and it binds only putrescine, not spermidine. To understand these different substrate specificities, model building of the PotF protein was performed on the basis of the PotD crystal structure. The hypothetical structure suggests that the side chain of Lys 349 in PotF inhibits spermidine binding because of the repulsive forces between its positive charge and spermidine. On the other hand, putrescine could be accommodated into the binding site without any steric hindrance because its molecular size is much smaller than that of spermidine, and the positively charged amino group is relatively distant from Lys 349.

Amino Acid Sequence↗

PubMed1996

Socioeconomic and behavioural risk factors for mortality of individuals with IDDM in Japan: population-based case-control study. Diabetes Epidemiology Research International (DERI) US-Japan Mortality Study Group.

The aim of this population-based, one-to-one matched-pair case-control study was to evaluate the factors concerning the markedly increased risk for dying among Japanese subjects with insulin-dependent diabetes mellitus (IDDM) from a social and behavioural perspective. The study was based on the population-based cohort of IDDM subjects in the Diabetes Epidemiology Research International Mortality Study. We studied 90 cases who died and 90 living control subjects, selected from the rest of the cohort, who were matched for sex, birth year, year of diagnosis and duration of diabetes. Socioeconomic and behavioural status were surveyed through a questionnaire. Conditional logistic regression analyses based on 55 respondent pairs revealed that the better educated patients (year of completing education: odds ratio = 0.66) who kept the same physician (number of times a patient changed physician: odds ratio = 2.77) and who attended a clinic specializing in diabetes (attendance at university hospital clinic: odds ratio = 0.18) injecting insulin several times a day (number of injections, odds ratio = 0.31) and more frequently attending the clinic (> or = 12 times per year, odds ratio = 0.23) were at substantially lower risk of death. The results begin to profile the patients with the highest risk of dying who could be identified earlier and undergo intervention treatment.

Adolescent↗

PubMed1996

Characterization of the human p57KIP2 gene: alternative splicing, insertion/deletion polymorphisms in VNTR sequences in the coding region, and mutational analysis.

We have isolated human cDNA and genomic clones of a gene termed p57KIP2, which is related to the p2I WAFI and p27 KIP1 genes that encode inducible inhibitors of cyclin-dependent kinase activity. The p57 gene contains three GC-rich introns of 166 bp, 566 bp, and 83 bp, and two of the four exons correspond to coding regions. Alternative splicing generates the heterogeneity in the translational initiations. As this gene has been localized to chromosomal band 11pI5.5, a region thought to be the location of a tumor suppressor gene(s) for carcinomas of the breast, bladder, and liver, we have examined a large number of tumors for genetic alterations of p57. Although no somatic mutation has been detected, we have found several normal variations in this gene, including four types of 12-bp in-frame deletions in the proline/alanine repeating domain, in which nearly 40 motifs, viz., 5'-CCGGCC-3', are tandemly repeated.

Alternative Splicing↗

PubMed1996

Wound infiltration with lidocaine prolongs postoperative analgesia after haemorrhoidectomy with spinal anaesthesia.

PURPOSE: There are few clinical data examining whether sensitization of peripheral nerves contributes to postoperative pain when the entry of noxious impulses to the central nervous system is blocked. We hypothesized that wound infiltration with lidocaine would provide better postoperative analgesia than with normal saline following haemorrhoidectomy with spinal blockade. METHODS: In a randomized, placebo-controlled, blinded study, 168 adults undergoing haemorrhoidectomy were allocated to two groups. In Group L (n = 88) local infiltration was provided with lidocaine 1% and in Group S (n = 80) with normal saline. Following spinal anaesthesia with lidocaine 3%, the surgeon infiltrated 15 ml of either infiltration solution to the surgical area. Postoperative analgesia was obtained by continuous epidural administration of 90 mg eptazocine in normal saline for 48 hr. Supplemental analgesics were given on request. Postoperative pain control was assessed at rest and during coughing with a 10 cm VAS on the 1st, 2nd, and 3rd postoperative days (POD). RESULTS: The VAS scores at rest in Group L were lower than those in Group S throughout the postoperative period. During coughing, VAS scores in Group S were increased on the 3rd postoperative day, while those in Group L remained constant (4.42 +/- 0.27 vs 3.14 +/- 0.28, P < 0.05). Fewer patients in Group L than in Group S required supplemental analgesics. CONCLUSION: Preoperative lidocaine infiltration to the surgical area provided prolonged postoperative analgesia in patients receiving haemorrhoidectomy with spinal anaesthesia.

Adult↗

PubMed1996

Anti-HIV-1 activity of thiadiazole derivatives: structure-activity relationship, reverse transcriptase inhibition, and lipophilicity.

The structure-activity relationship of the non-nucleoside HIV-1-specific reverse transcriptase (RT) inhibitors 4-phenyl-1,2,5-thiadiazol-3-yl N,N-dialkylcarbamate (TDA) derivatives was investigated with respect to their anti-HIV-1 activity, RT inhibition, and lipophilicity. 4-Phenyl-1,2,5-thiadiazol-3-yl N,N-dimethylcarbamate inhibited HIV-1-induced cytopathic effect (CPE) by 50% at a concentration of 28.8 microM in MT-4 cells. The activity increased more than 100-fold when the hydrogens at the 2-position and the 6-position in phenyl moiety were substituted by chlorines. However, the derivative with a chlorine at the 4-position of phenyl moiety did not show any inhibition of HIV-1 replication at its non-toxic concentrations. All of the 4-(2,6-dichlorophenyl)-1,2,5-thiadiazol-3-yl N-methyl-N-alkylcarbamates proved inhibitory to HIV-1 replication in the nanomolar concentration range. The TDA derivatives that showed anti-HIV-1 activity also inhibited RT activity in an enzymatic assay. However, the TDA derivatives did not show any specific inhibition of a non-nucleoside RT inhibitor (NNRTI)-resistant mutant and its RT activity. When the TDA derivatives were examined for their inhibitory effect on HIV-1 replication in the presence of 50% human serum, the activity significantly decreased depending on-their lipophilicity.

Anti-HIV Agents↗

PubMed1996

A role of PDI in the reductive cleavage of mixed disulfides.

We previously reported that protein disulfide isomerase (PDI) can dissociate the glutathione molecule in vitro from the mutant human lysozyme (hLZM) C77A-a, which is modified with glutathione at Cys95; however, it seems structurally difficult for PDI to attack either the disulfide bond or the side chain of the cysteine residue of a mixed disulfide. To investigate the function of PDI, we introduced several glutathione and cysteine derivatives at Cys95, instead of the glutathione of C77A-a. Using thiol compounds modified by 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), we could easily modify the free thiol group of C77A-b (C77A with no glutathionylation), without denaturation. For all of the modifications we tested, a negative correlation was found between the initial rate and the acceleration ratio of the reductive cleavage of mixed disulfides with PDI. A mutant PDI (hPDIM), which has no thiol-disulfide exchange activity, suppressed the reductive cleavage of the mixed disulfide of C77A-a with hPDI, suggesting that hPDI non-covalently interacted with the substrates. Taking account of the results of the structural analysis, we conclude that one of the functions of PDI in vivo lies in relaxing the structure around the disulfide bond, as well as in exchanging the thiol-disulfide bonds.

Amino Acid Sequence↗

PubMed1996

Mutational analysis of mismatch repair genes, hMLH1 and hMSH2, in sporadic endometrial carcinomas with microsatellite instability.

Microsatellite instability, monitored by replication error (RER), has been observed in both sporadic and hereditary types of endometrial carcinoma. In the hereditary tumors, this instability is considered to be caused by a germline defect in the DNA mismatch-repair system. We previously reported that nearly one-quarter of sporadic endometrial carcinomas examined revealed an RER-positive phenotype at multiple microsatellite loci. To investigate the role of genetic alterations of DNA mismatch-repair genes in sporadic endometrial carcinomas, we screened 18 RER(+) endometrial carcinomas for mutations of hMLH1 and hMSH2. Although we found no germline mutations, we detected two somatic mutations of hMLH1 in a single endometrial cancer; these two mutations had occurred on different alleles, suggesting that two separate mutational events had affected both copies of hMLH1 in this particular tumor. These data implied that mutations of hMLH1 or hMSH2 play limited roles in the development of sporadic endometrial carcinomas, and that the tumors with genetic instability might have alterations of other mismatch-repair genes, such as hPMS1 and hPMS2, or of unknown genes related to the mismatch-repair system.

Adaptor Proteins, Signal Transducing↗

PubMed1996

Molecular cloning and mapping of a human cDNA (SC5DL) encoding a protein homologous to fungal sterol-C5-desaturase.

We have isolated a human cDNA clone homologous to fungal ERG3, a gene encoding sterol C-5 desaturase. The full nucleotide sequence of this human cDNA revealed a 708-bp open reading frame that encodes a 236-amino-acid polypeptide. The gene was expressed in all normal human tissues examined. We determined its location to chromosome 11q23.3 by fluorescence in situ hybridization.

Amino Acid Sequence↗

PubMed1996

A major improvement in the prognosis of individuals with IDDM in the past 30 years in Japan. The Diabetes Epidemiology Research International Study Group.

OBJECTIVE: To evaluate the time trends of mortality among individuals with IDDM in Japan. RESEARCH DESIGN AND METHODS: A historical prospective study of two independent population-based cohorts composed of individuals who were diagnosed between 1965 and 1969 (1960s cohort) and between 1975 and 1979 (1970s cohort), which included 286 IDDM patients (onset age < 18 years) for the 1960s cohort and 779 patients for the 1970s cohort, was performed. After 10 years of observation, mortality status and causes of deaths between the two cohorts were compared. RESULTS: The age-adjusted mortality rate per 100,000 person-years of the 1960s cohort was 754 (95% CI, 471-1,141); in contrast, that of the 1970s cohort was only 196 (95% CI, 107-329) (P < 0.001). The standardized mortality ratio of the 1960s cohort was 1,432 (95% CI, 898-2,161), and that of the 1970s cohort was 489 (95% CI, 267-821). Analyses of the causes of deaths revealed a marked decline in recent years in the number of deaths by acute complications and renal disease. CONCLUSIONS: A major decline in the mortality of diabetic children in Japan may be attributed to the dramatic changes in the quality of care and medical infrastructure that occurred after the mid-1970s.

Adolescent↗

PubMed1996

Expression of basic fibroblast growth factor mRNA in developing choroidal neovascularization.

PURPOSE: Basic fibroblast growth factor (bFGF) is an angiogenic peptide that may be important in the pathogenesis of choroidal neovascularization. We attempted to determine the transcription of the bFGF gene during the development of experimentally induced choroidal neovascularization. METHODS: Rat bFGF cDNA was inserted in the pBluescript to prepare antisense and sense riboprobes. Multiple krypton laser burns were applied to the posterior poles of the eyes of pigmented rats according to a protocol described for producing subretinal neovascularization in these animals. At intervals of up to 4 weeks after photocoagulation, the eyes were removed and cut into thin sections. The sections were subjected to histopathological analysis, cell proliferation study, or in situ hybridization with digoxigenin (DIG)-labeled single-strand riboprobes synthesized from rat bFGF cDNA. RESULTS: In normal adult rat retinas, bFGF mRNA expression was mainly observed in the ganglion cell layer and the inner nuclear layer. After laser photocoagulation, proliferation of RPE cells, fibroblast-like cells and cells in the choroid in the lesions were observed. Expression of bFGF mRNA was observed in the lesions 3 days to 2 weeks after laser treatment. Signals of bFGF mRNA were detected in the proliferating RPE-like cells, choroidal vascular endothelial cells and fibroblast-like cells, all of which are essential for neovascularization. However, bFGF mRNA expression was no longer detectable in these cells 4 weeks after photocoagulation. CONCLUSIONS: Our findings indicate that bFGF is normally transcribed in ganglion cells and the inner nuclear cell layer. During the neovascularization that followed laser photocoagulation, bFGF mRNA expression was detected within the laser lesions. It is thus probable that bFGF acts as a mediator in the neovascularization process.

Animals↗

PubMed1996

[Expression of basic fibroblast growth factor and its receptor in the process of wound healing of rat retina after laser photocoagulation].

We investigated the expression of mRNA of basic fibroblast growth factor (bFGF) and FGF receptor 1 in rat retina after laser photocoagulation using in situ hybridization method. Pigmented rats (Brown Norway strain) received weak photocoagulation by krypton laser (500 microns, 0.05 sec, 60 mW) in the posterior retina. On 1, 3, 5, 7, 14 days after laser photocoagulation, the rats were fixed by perfusion with phosphate-buffered 4% paraformaldehyde and the eyes were enucleated. The eyes were further fixed by immersion in the same fixative, then quickly frozen in liquid nitrogen and finally sectioned with a cryostat. In situ hybridization was performed on frozen sections with digoxigenin (DIG) labeled riboprobes synthesized from rat bFGF cDNA and FGF receptor 1 cDNA. In normal chorioretinal tissue, the signals of bFGF and FGF receptor 1 mRNA were seen in the ganglion cell layer and inner nuclear layer. On day 3 after photocoagulation, we observed expression of bFGF and FGF receptor 1 mRNA in the proliferating retinal pigment epithelial (RPE) cells and endothelial cells of choriocapillaris at the photocoagulated lesion. We also observed expression of bFGF mRNA in some macrophage-like cells. On day 14 after photocoagulation, these expressions had disappeared. Our results suggest that bFGF may be involved in the process of retinal wound healing after laser photocoagulation.

Animals↗

PubMed1996

FGF receptor 1 expression in experimental choroidal neovascularization.

Fibroblast growth factor (FGF) is an important factor in neovascularization. To clarify the role of FGF, we demonstrated the expression of FGF receptor 1 mRNA in experimentally induced choroidal neovascularization using in situ hybridization. Krypton laser photocoagulation was applied to the posterior retina of colored rats to induce choroidal neovascularization; the eyes were removed at various intervals after photocoagulation. Chorioretinal sections were made, and FGF receptor 1 cDNA fragments were used to make antisense and sense probes for in situ hybridization. In normal chorioretinal tissue, stain indicating FGF receptor 1 mRNA was observed in the ganglion cells and the inner nuclear layer. After photocoagulation, FGF receptor 1 mRNA appeared in the retinal pigment epithelial cells, in melanocytes of the choroid and in the choroidal blood vessel wall of the photocoagulation lesions. This suggests that FGF is involved in the process of neovascularization. Previous studies have reported that the capillary endothelial cells and retinal pigment epithelial cells produce basic FGF in vitro; FGF may affect the cells in an autocrine or paracrine manner.

Animals↗

PubMed1996

Gene expressions of basic fibroblast growth factor and its receptor in healing of rat retina after laser photocoagulation.

Basic fibroblast growth factor (bFGF) stimulates the mitogenesis of various cells and plays a key role in wound repair. Using in situ hybridization, we studied mRNA expressions of bFGF and one of its receptors, FGF receptor 1 (FGFR1), during wound repair of the rat retina after laser photocoagulation. Gene expressions of bFGF and FGFR1 were detected in the ganglion cell and inner nuclear layers of the normal adult rat retina. On day 3 following laser photocoagulation, proliferating retinal pigment epithelial (RPE) cells of the lesion showed intense gene expressions of bFGF and FGFR1. Macrophage-like cells that migrated into the lesion also showed gene expression of bFGF. These gene expressions decreased over time. The finding of elevated gene expressions of bFGF and FGFR1 after laser photocoagulation suggests the bFGF may be a factor in retinal wound repair.

Animals↗