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Biomedical subjects

H Shimada

Publications and source records attributed to H Shimada.

At least 325 records · Page 18Linked to original sources
PubMed1998

Usefulness of three-dimensional computed tomography for anatomic liver resection: sub-subsegmentectomy.

BACKGROUND: Precise subtotal hepatectomies based on the vascular anatomy revealed by preoperative three-dimensional computed tomography (3D-CT) were reviewed to examine the usefulness of 3D-CT. METHODS: The clinical records and 3D-CT images of 20 patients with 24 hepatomas less than 50 mm in diameter who underwent hepatectomy for hepatocellular carcinoma and metastatic tumors and the usefulness of 3D-CT were assessed. Couinaud's classification of liver subsegments and Takayasu's classification of sub-subsegments were used as the criteria for the anatomic division. RESULTS: The accuracy in localizing tumors in a small subsegment of the liver was 75% (18 of 24 tumors) for conventional CT and 100% (24 of 24 tumors) for 3D-CT (p < 0.05). 3D-CT images made it possible to perform complete resection confined to the portal unit containing the tumor in patients with poor liver function. This method allowed complete preservation of the circulation of the remnant liver, thus reducing complications. CONCLUSIONS: The 3D-CT technique provides more accurate diagnosis and a realistic virtual image of a tumor's location in the liver and so makes possible the anatomic resection of the liver. Because diagnostic errors could result in such clinical complications as postoperative bile leakage, this is a useful technique for hepatectomy, especially for sub-subsegmentectomy.

Aged↗
PubMed1998

Inhibitory effect of matrilysin antisense oligonucleotides on human colon cancer cell invasion in vitro.

In colorectal cancer, matrilysin (matrix metalloproteinase-7) is mainly produced by the tumor cells themselves and is thought to play an important role in tumor invasion and metastasis. In the study reported here, we examined the effects of matrilysin antisense phosphorothioate oligonucleotides on both the expression of matrilysin and the invasive potential of the human colon cancer cell line CaR-1 in vitro. To select the most specific and potent oligonucleotide sequence, we performed extensive analyses of the binding specificities of all antisense candidates in the GenBank database by using a computer program we developed. As a result, a 15-mer matrilysin-specific antisense oligonucleotide that hybridizes to the coding region of matrilysin mRNA (AS-1) and a random control oligonucleotide (CL-1) were designed. Reverse transcription-polymerase chain reaction and western blot analysis demonstrated that 10 microM AS-1 suppressed matrilysin expression at both the mRNA level (92%) and protein level (64%). In vitro invasion assays demonstrated that this same concentration of AS-1 inhibited the ability of cells to invade a reconstituted basement membrane by 50% as compared with the ability of untreated cells to do so. On the other hand, CL-1, which had the same length and GC content as AS-1, did not show any inhibitory effect. These results demonstrate that the antisense oligonucleotide AS-1 inhibits matrilysin activities in a sequence-specific manner and suggest that AS-1 has the potential to be used as an anti-metastatic agent in an in vivo experimental model of colon cancer.

Antineoplastic Agents↗
PubMed1998

Differential expression of sea urchin Otx isoform (hpOtxE and HpOtxL) mRNAs during early development.

Two distinct types of orthodenticle-related proteins (early type: HpOtxE, late type: HpOtxL) of the sea urchin, Hemicentrotus pulcherrimus, have been implicated as enhancer element binding factors of the aboral ectoderm-specific arylsulfatase (HpArs) gene. In order to understand the role of these isoforms during sea urchin development, we have isolated and characterized HpOtx gene. Here we describe the spatial expression patterns of HpOtxE and HpOtxL mRNAs and effects of overexpression of these mRNAs on embryogenesis. Whole-mount in situ hybridization using each isoform-specific probe reveals the complex and dynamic change of expression patterns among three germ layers. HpOtxE mRNA is maternally stored and exists apparently in a nonlocalized manner by the blastula stage. After hatching, HpOtxE transcripts are expressed predominantly in presumptive endoderm cells and gradually decrease during gastrulation. Signals for HpOtxL mRNA are intense at the vegetal half after hatching and subsequently, its expression is restricted to the micromere-derived cells. After primary mesenchyme cell (PMC) ingression, HpOtxL transcripts are localized at the vegetal plate and thereafter, concentrated primarily in ectoderm. Eggs injected with HpOtxE or HpOtxL mRNA develop into similar radialized structures without PMC ingression and gut invagination, whose oral-aboral axes are disrupted. Overexpression of HpOtxE induces accumulation of HpOtxL mRNA at the significantly earlier stages, though HpOtxL overexpression inhibits the accumulation of HpOtxE transcripts. Expression patterns of HpOtxE and HpOtxL in all three germ layers and dramatic morphological changes observed in the mRNA-injected embryos suggest that each HpOtx isoform has an important role in sea urchin embryogenesis.

Animals↗
PubMed1998

Analysis of renal pathology and drug history in 158 Japanese patients with rheumatoid arthritis.

To clarify the characteristics of renal pathology and its correlation with disease-modifying antirheumatic drugs (DMARDs) in patients with rheumatoid arthritis (RA), renal biopsy findings from 158 Japanese RA patients with urinary abnormalities and/or renal dysfunction were analyzed retrospectively in the period between 1979 and 1996. Urologic abnormality and urinary tract infection were ruled out in all patients. Light and immunofluorescence (IF) microscopy were performed in all patients. Mesangial proliferative glomerulonephritis (MesPGN) was diagnosed in 54 patients, membranous nephropathy (MN) in 49, and secondary amyloidosis (AM) in 30. Renal dysfunction was more frequent in patients with AM (22/30) than in patients without (40/128). Forty of 49 MN patients developed renal disorders during DMARDs therapy. The prevalence of DMARD-related MN increased during the period of observation. The fact that DMARDs are of very frequent use in recent Japanese RA patients may reflect the prevalence of MN in this study. Two thirds of patients with MesPGN developed renal disorders when no DMARDs were used. One half of 54 MesPGN patients demonstrated IgA glomerulonephritis (GN) by IF. The prevalence of primary renal diseases in Japan may reflect the frequency of IgA GN in Japanese RA patients. Furthermore, diffuse thinning of the glomerular basement membrane (GBM) was observed in 30 of 81 patients with electron microscopy. RA itself may underlie the pathogenesis of GBM thinning, and drugs used for RA treatment may also accelerate the development of this lesion. In conclusion, although MesPGN, MN, and AM may be relatively more common, IgA GN and GBM thinning also were other frequent entities in Japanese RA patients. No correlation was observed between DMARDs and renal disorders excepting MN.

Adolescent↗
PubMed1998

[Inflammatory mediator and organ dysfunction syndrome].

Inflammatory mediators include endotoxin (ETX), cytokines (interleukins [ILs], tumor necrosis factors [TNFs], and interferons), eicosanoids (prostaglandins and thromboxanes), reactive oxygen species (O2-, NO, and ONOO-), complements (C3 and C4), and stress hormones (catecholamine, cortisol, vasopressin, and growth hormone). These mediators work to maintain homeostasis under stressful conditions through a complex chain reaction or cascade that results in transient tissue damage known as the inflammatory response. The inflammatory response is decreased by a negative feedback system, which consists not only of the self-inhibitory action of ETX, TNF-alpha, IL-1, and IL-8, but also of the production of antiinflammatory mediators such as IL-4, -10, -11, and -13, TGF-beta, IL-Ra, and sTNFR. If excessive stress or a second attack of stress results in a higher level of inflammation-producing mediators than of inflammation-inhibiting mediators, tissue destruction occurs due to activation and infiltration of inflammatory cells or necrosis due to endothelial injury is seen, followed by disruption of homeostasis, organ dysfunction, and organ failure (multiple organ dysfunction syndrome [MODS] or multiple organ failure [MOF] induced by SIRS). In experimental liver dysfunction after 95% hepatectomy, massive apoptosis of hepatocytes is induced by prolonged hypercytokinemia, ONOO- production, decreased mitochondrial membrane potential of hepatocytes, and decreased Bc12 levels. On the other hand, if the antiinflammatory response is greater than the inflammatory response (CARS) a compromised state and refractory infection are seen, followed by progressive, irreversible organ dysfunction (MODS or MOF induced by CARS).

Animals↗
PubMed1998

[Effects of the aldose reductase inhibitor on diabetic polyneuropathy--the efficacy of F wave measurement].

The effects of the aldose reductase inhibitor epalrestat (150 mg/day) on electrophysiological function were examined in 22 NIDDM patients with diabetic polyneuropathy for 6 months. Although no significant differences were observed in sensory (the sural nerve) or motor (the posterior tibial nerve) conduction velocities and amplitude, only F wave conduction velocities were significantly improved at 3 and 6 months after the treatment. There were no significant changes in CV-RR, vibration threshold and laboratory data. No serious side effects were observed during the therapeutic trial. This study suggests F wave is appropriate for the assessment of diabetic neuropathy and for therapeutic trials.

Aldehyde Reductase↗
PubMed1998

Direct reverse transcription-PCR on oligo(dT)-immobilized polypropylene microplates after capturing total mRNA from crude cell lysates.

To simplify gene expression analysis, oligo(dT)-immobilized polypropylene microplates were used serially to capture mRNA, synthesize cDNA, and amplify specific genes. The amounts of immobilized oligonucleotide, hybridized mRNA, and synthesized cDNA were quantified fluorometrically using either Yoyo-1 or AttoPhos. The immobilized oligonucleotides captured approximately 40-55% of mRNA directly from crude cell lysates. Hybridized mRNA was then amplified by one-step reverse transcription (RT)-PCR with rTth polymerase or two-step PCR with initial cDNA synthesis followed by PCR, where the latter exhibited more sensitivity. In two-step RT-PCR, microplates can be reused for multiple PCRs with the same or different primer sets because synthesized cDNA was covalently attached to the plates at its 5' end. We believe this microplate may be acceptable as a platform for various mRNA expression analyses, including basic research, drug screening, and molecular toxicology, as well as for molecular pathological diagnostics.

Animals↗
PubMed1998

[Hepatic resection for advanced carcinoma of the gallbladder].

Hepatic resection for advanced carcinoma of the gallbladder must be decided upon based on the modes of cancer spread to the liver. The cystic vein through the liver bed is considered an important route of liver metastasis, because liver metastases of gallbladder carcinoma are found frequently around the liver bed. About 70% of early metastatic foci demonstrated microscopically occur in segments 4a and 5. Resection of segments 4a and 5 is considered to be an adequate range of hepatectomy for patients with subserosal invasion, because early metastatic foci are detected not only in patients with direct invasion of the liver but also in those without direct invasion. For patients with direct liver invasion, various degrees of hepatic resection are needed to comply with the depth of direct invasion. It is necessary to achieve negative surgical margins 2 cm from the tumor. Because cancer cells extend along the Glissonian sheath in patients with hilar invasion, extended right hepatectomy with caudate lobectomy is required in these patients. A future problem is to establish the safety of extended hepatectomy in these patients.

Gallbladder Neoplasms↗
PubMed1997

Isolation of cDNA for an NADP-malic enzyme from Aloe arborescens.

NADP-malic enzyme catalyzes the reaction of decarboxylation from malate. In CAM plants, functions of this enzyme diverged to include both photosynthetic and non-photosynthetic roles. A full length cDNA for an NADP-malic enzyme was isolated from an 'obligate' CAM plant aloe (Aloe arborescens). The cDNA contains an ORF encoding 592 amino acid residues, whose sequence is highly homologous to the known plant NADP-malic enzymes. This gene is constitutively expressed in all organs in a low level. The amount of the transcript exhibited no diurnal variation, suggesting that this gene is not involved in photosynthetic functions.

Aloe↗
PubMed1997

The mechanisms of nickel uptake by rat primary hepatocyte cultures: role of calcium channels.

The present study was designed to clarify the mechanism of nickel (Ni) uptake in primary cultures of rat hepatocytes. Exposure of the hepatocytes to Ni (2-50 microM; as NiCl2) for up to 6 h was not cytotoxic, as assessed by the tetrazolium-based dye (MTT) assay. Hepatocytes were treated with 10 microM NiCl2 in the absence or presence of calcium (Ca) and magnesium (Mg) (1 mM). Ni uptake was increased by 19% in medium lacking Mg or Ca and was increased by 37% in Ca- and Mg-free medium. The role of Ca channels on Ni uptake by the hepatocytes was investigated. Pretreatment with nicardipine or verapamil (200 microM), potent inhibitors of Ca channels, decreased Ni uptake by 20%. This effect was only observed when the cells were incubated in the absence of Ca. Pretreatment with vasopressin (100 nM), a well-known Ca channel agonist, significantly increased Ni uptake by the hepatocytes (24%). To determine the involvement of carrier-mediated processes on Ni uptake, the effect of temperature was also investigated. At 4 degrees C the Ni uptake was decreased by 20% compared to uptake at 37 degrees C. These results indicate that Ni uptake by the hepatocytes occurs, at least in part, through the Ca channel transport processes. Further study will be required to assess what other mechanisms are involved.

Animals↗
PubMed1997

Prostaglandin E1 protects against ischemia-reperfusion injury of the liver by inhibition of neutrophil adherence to endothelial cells.

BACKGROUND: This study investigates the protective mechanism of prostaglandin E1 (PGE1) against hepatic ischemia-reperfusion injury in vivo. It has been demonstrated that activated leukocytes contribute to ischemia-reperfusion injury, and that administration of the monoclonal antibody (mAb) for adhesion molecules reduces the injury by inhibiting leukocyte-endothelial cell adhesion. We therefore attempted to find out whether PGE1 has an effect on the inhibition of neutrophil adherence to endothelial cells after reperfusion. METHODS: We administered anti-intercellular adhesion molecule 1 (ICAM-1) mAb, antiserum against rat polymorphonuclear leukocytes, or PGE1 to a rat model of left lobar ischemia for 60 min followed by reperfusion. Leukocyte adherence was observed by intravital fluorescence microscopy. The effect of PGE1 on the expression of adhesion molecules was analyzed by immunohistochemistry and flow cytometry. RESULTS: Ischemia-reperfusion caused endothelial dysfunction and hepatocellular injury with leukostasis in postsinusoidal venules. Anti-ICAM-1 mAb administration or leukopenia ameliorated both the hepatocellular injury and endothelial dysfunction. Although PGE1 administration did not affect the serum interleukin-8 level, it significantly decreased hepatic injury and leukostasis in the reperfused liver. Immunohistochemical findings showed that PGE1 decreased ICAM-1 expression on endothelial cells, but did not affect lymphocyte function-associated antigen 1, and membrane attack complex 1 on neutrophils in flow cytometric analysis. CONCLUSIONS: We conclude that PGE1 protects the liver against ischemia-reperfusion injury by reducing leukocyte-endothelial cell adhesion via down-modulation of ICAM-1 expression on the endothelium.

Alprostadil↗
PubMed1997

Expression of an allogeneic MHC DRB transgene, through retroviral transduction of bone marrow, induces specific reduction of alloreactivity.

BACKGROUND: Transfer of MHC class II genes, through allogeneic bone marrow (BM) transplantation, induced long-lasting acceptance of renal allografts in miniature swine. To adapt this approach to the clinic, we have now examined whether somatic transfer of allogeneic class II DR genes, into otherwise autologous bone marrow cells (BMC), can provide the matching required for inducing immune tolerance. METHODS: Autologous BMC were transduced ex vivo with recombinant retroviruses for allogeneic DRB followed by BM transplantation. The recipients were then challenged with kidney allografts solely matched to the DRB transgene. RESULTS: Five miniature swine received autologous BMC conditioned with growth factors and transduced with recombinant retrovirus vectors containing allogeneic (n=4) or syngeneic (n=1) class II DRB genes and a drug-resistance marker. Expression of retrovirus-derived products in BM-derived cells was demonstrated by the detection of drug-resistant colony-forming progenitors and the presence of DRB retrovirus transcripts in peripheral cells. Analysis of selective mixed lymphocyte reaction responses to DR or DQ antigens indicated decreased reactivity toward the transduced DR gene product. Among all of the animals receiving fully mismatched kidney allografts, but with DRB matched to the transduced DRB, the one with the highest gene transduction rate showed stable allograft function and essentially normal renal histology for 2.5 years. A control animal, which received a syngeneic DRB gene, rejected its kidney allograft in 120 days after an earlier rejection crisis. CONCLUSIONS: These studies demonstrate that allogeneic MHC gene transfer into BM provides a new strategy for inducing tolerance across MHC barriers.

Animals↗
PubMed1997

Cloning and expression of rat 25-hydroxyvitamin D3-1alpha-hydroxylase cDNA.

A full-length cDNA for the rat kidney mitochondrial cytochrome P450 mixed function oxidase, 25-hydroxyvitamin D3-1alpha-hydroxylase (P4501alpha), was cloned from a vitamin D-deficient rat kidney cDNA library and subcloned into the mammalian expression vector pcDNA 3.1(+). When P4501alpha cDNA was transfected into COS-7 transformed monkey kidney cells, they expressed 25-hydroxyvitamin D3-1alpha-hydroxylase activity. The sequence analysis showed that P4501alpha was of 2,469 bp long and contained an ORF encoding 501 amino acids. The deduced amino acid sequence showed a 53% similarity and 44% identity to the vitamin D3-25-hydroxylase (CYP27), whereas it has 42.6% similarity and 34% identity with the 25-hydroxyvitamin D3-24-hydroxylase (CYP24). Thus, it composes a new subfamily of the CYP27 family. Further, it is more closely related to the CYP27 than to the CYP24. The expression of P4501alpha mRNA was greatly increased in the kidney of vitamin D-deficient rats. In rats with the enhanced renal production of 1alpha,25-dihydroxyvitamin D3 (rats fed a low Ca diet), P4501alpha mRNA was greatly increased in the renal proximal convoluted tubules.

Amino Acid Sequence↗
PubMed1997

Serial brain CT in corticobasal degeneration: radiological and pathological correlation of two autopsy cases.

This report concerns serial brain computed tomography (CT) images in two patients with corticobasal degeneration (CBD). The diagnosis of CBD was confirmed by neuropathological examination. In one case, we obtained serial brain CT images for one year and five months, and in the other, for three years and four months. The CT images showed that the anterior portions of the cerebrum atrophied progressively with the length of the disease. This was also seen in the CT images with respect to the caudate nucleus. Regarding radiological and pathological correlations, we consider that the progressive atrophy of the anterior portions of the cerebrum, seen in brain CT images, is ascribed to neuronal loss and gliosis in the anterior portions of the cerebrum. We also believe that the observed caudate nucleus atrophy is due to loss of neurons and gliosis in this structure, and also to the fibrillary gliosis of the cerebral white matter. The progressive atrophy of the caudate nucleus detected in brain CT is a valuable feature for the neuroradiological diagnosis of CBD.

Aged↗
PubMed1997

Governing step of metastasis visualized in vitro.

Metastasis is the ultimate life-threatening stage of cancer. The lack of accurate model systems thwarted studies of the metastatic cell's basic biology. To follow continuously the succeeding stages of metastatic colony growth, we heritably labeled cells from the human lung adenocarcinoma cell line ANIP 973 with green fluorescent protein (GFP) by transfection with GFP cDNA. Labeled cells were then injected intravenously into nude mice, where, by 7 days, they formed brilliantly fluorescing metastatic colonies on mouse lung [Chishima, T., Miyagi, Y., Wang, X., Yang, M., Tan, Y., Shimada, H., Moossa, A. R. & Hoffman, R. M. (1997) Clin. Exp. Metastasis 15, 547-552]. The seeded lung tissue was then excised and incubated in the three-dimensional sponge-gel-matrix-supported histoculture that maintained the critical features of progressive in vivo tumor colonization while allowing continuous access for measurement and manipulation. Tumor progression was continuously visualized by GFP fluorescence in the same individual cultures over a 52-day period, during which the tumors spread throughout the lung. Histoculture tumor colonization was selective for lung cancer cells to grow on lung tissue, because no growth occurred on histocultured mouse liver tissue, which was also observed in vivo. The ability to support selective organ colonization in histoculture and visualize tumor progression by GFP fluorescence allows the in vitro study of the governing processes of metastasis [Kuo, T.-H., Kubota, T., Watanbe, M., Furukawa, T., Teramoto, T., Ishibiki, K., Kitajima, M., Moossa, A. R., Penman, S. & Hoffman, R. M. (1995) Proc. Natl. Acad. Sci. USA 92, 12085-12089]. The results presented here provide significant, new opportunities to understand and to develop treatments that prevent and possibly reverse metastasis.

Adenocarcinoma↗