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Biomedical subjects

M Matsushima

Publications and source records attributed to M Matsushima.

At least 73 records · Page 4Linked 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↗
PubMed1997

Novel selection method for engineered antibodies using the mechanism of Fv fragment stabilization in the presence of antigen.

Although the heavy and light chain domains of some antibody variable region fragments (Fvs) readily dissociate under physiological conditions, the Fvs are stable in the presence of antigen. This 'antigen-driven Fv stabilization mechanism' was applied to the selection of clones with specificity toward target antigens. The results can be summarized as follows. (i) Some of the residues in the heavy chain complementarity determining region 2 (HCDR2) of anti-hen egg white lysozyme (HEL) monoclonal antibody HyHEL10 heavy chain variable region (VH) were randomized. (ii) The randomized VH fragments of HyHEL10 were displayed on a filamentous bacteriophage and mixed with the target antigen, before being applied to a light chain variable region (VL) which was immobilized on microtiter plates and subjected to selection by panning. (iii) After four rounds of panning, four clones that showed significant binding to human lysozyme (hL), which HyHEL10 recognized poorly, were selected from the HCDR2 library. (iv) The soluble Fv fragments selected were expressed in Escherichia coli, purified, and subjected to an inhibition assay of lysozyme enzymatic activities and an isothermal titration calorimetry. These Fv fragments had increased affinity toward hL, and thermodynamic analysis suggested that the reduced entropy loss due to binding by the replacement of residues in HCDR2 resulted in the higher hL binding activity.

Amino Acid Sequence↗
PubMed1997

[Expression of basic fibroblast growth factor and fibroblast growth factor receptor 1 in the experimental retinal vein occlusion model].

Retinal ischemia promotes retinal neovascularization. Vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) are important growth factors for neovascularization. We did experimental retinal vein occlusion (RVO) and examined the expression of basic FGF and FGF receptor 1(one of the basic FGF receptors) by in situ hybridization. We used adult pigmented rats (Brown-Norway strain). Dye laser photocoagulation (577 nm) was applied to the retinal arteries and veins within two disc diameters of the optic nerve head to injure the retinal vessels. After one week, laser photocoagulation was applied to only the retinal veins to occlude them (RVO model). As a control, laser photocoagulation was applied to the posterior retina avoiding the retinal vessels. After treatment, the eyes were removed and 10 microns thick cryostat-cut chorioretinal section were used for in situ hybridization with probes as mentioned above. In the RVO model, expression of messenger RNA of basic FGF (b-FGF) and FGF receptor 1 increased in the inner nuclear layer and the inner segment of the photoreceptors, and appeared in the retinal vessel wall in the early stage. This shows that b-FGF and FGF receptor 1 increased in the ischemic retina, and were produced on the retinal vessel wall. This suggests that b-FGF may be involved in protection, regeneration, and proliferation of the retinal vascular endothelial cells in retinal circulatory disturbance.

Animals↗
PubMed1997

[A case of water intoxication presenting as urinary retention in a psychotic patient].

A 43-year-old man, who had been treated for chronic schizophrenia, was admitted to our hospital with the chief complaint of urinary retention. His serum levels of sodium and osmotic value were low and serum creatine phosphokinase (CPK) was elevated to 2,624 mg/dl. He had been consuming about 9 liters of water a day for ten years. A diagnosis of water intoxication was made and treated successfully with water restriction and drip infusion. To our knowledge, this is the 23rd case of water intoxication with serum creatine phosphokinase elevation reported in the Japanese literature and this is the first case with the chief complaint of urinary retention.

Adult↗
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

Crystallization and preliminary X-ray analysis of the primary receptor (PotD) of the polyamine transport system in Escherichia coli.

The primary receptor (potD, M(r) = 39 000) of the polyamine transport system in Escherichia coli has been crystallized by the vapor-diffusion method. Two crystal forms were obtained in the presence of spermidine, and were examined by X-ray analysis. Form I crystals, which diffract to 2.5 A resolution, belong to the space group P2(1), with unit-cell dimensions a = 145.3, b = 69.1, c = 72.5 A and beta = 107.6 degrees. Four molecules are contained in an asymmetric unit. These form two dimers that are related to each other by a local translation of about half of the unit cell along the a axis. The two protein molecules in each dimer are similarly related by a local dyad. Form II crystals diffract to 1.8 A resolution and belong to the space group I4(1), with unit-cell dimensions a = b = 130.3 and c = 38.7 A. They contain one molecule per asymmetric unit.

Journal Article↗
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↗