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Biomedical subjects

M Hosokawa

Publications and source records attributed to M Hosokawa.

At least 91 records · Page 5Linked to original sources
PubMed1999

cDNA cloning, characterization and stable expression of novel human brain carboxylesterase.

The DNA sequence encoding a novel human brain carboxylesterase (CES) has been determined. The protein is predicted to have 567 amino acids, including conserved motifs, such as GESAGG, GXXXXEFG, and GDHGD which comprise a catalytic triad, and the endoplasmic reticulum retention motif (HXEL-COOH) observed in CES families. Their gene products exhibited hydrolase activity towards temocapril, p-nitrophenyl-acetate and long-chain acyl-CoA. Since the molecular masses of these gene products are similar to those that exist in capillary endothelial cells of the human brain [Yamamda et al. (1994) Brain Res. 658, 163-167], these CES isozymes may function as a blood-brain barrier to protect the central nervous system from ester or amide compounds.

Amino Acid Sequence↗
PubMed1999

Association of matrilysin expression with recurrence and poor prognosis in human esophageal squamous cell carcinoma.

Matrix metalloproteinase-7 (matrilysin) has been implicated in tumor invasion and metastasis as well as tumor initiation and growth. In this study, we analyzed an association between immunohistochemically detected matrilysin expression at the invasive front in esophageal squamous cell carcinomas and clinicopathological characteristics and determined whether matrilysin predicts recurrence and/or survival Matrilysin expression at the invasive front was detected in 49% of 100 carcinoma tissues and was associated with the depth of invasion (P < 0.0001), advanced tumor stage (P = 0.0159), recurrences (P = 0.0002), and recurrences within the first postoperative year (P = 0.002). Patients with matrilysin-positive carcinoma had a significantly shorter disease-free and overall survival time than did those with a matrilysin-negative one (P < 0.0001). Matrilysin remained a significant predictive value for disease-free and overall survival in multivariate analysis, including conventional clinicopathological factors (P = 0.0007 and 0.0004, respectively). Our results suggest that matrilysin may play a key role in the progression of esophageal carcinoma and that its detection may be useful for the prediction of recurrence and poor prognosis and, possibly, for selecting patients for anti-matrix metalloproteinase therapy.

Carcinoma, Squamous Cell↗
PubMed1999

Intraoperative radiation therapy to the upper mediastinum and nerve-sparing three-field lymphadenectomy followed by external beam radiotherapy for patients with thoracic esophageal carcinoma.

BACKGROUND: In patients with thoracic esophageal carcinoma, radical dissection of the upper mediastinal lymph nodes often leads to complications such as recurrent laryngeal nerve palsy and subsequent pulmonary disorders. Intraoperative radiation therapy (IORT) to the upper mediastinum and nerve-sparing three-field lymphadenectomy followed by external beam radiotherapy has been developed to improve the locoregional control rate without resulting in these major postoperative complications. METHODS: Three-field lymphadenectomy, including cervical, mediastinal, and abdominal lymph node dissection, was performed. Dissection of the upper mediastinum was conservative to preserve recurrent laryngeal nerve function. IORT of 12-25 grays (Gy) was applied to the upper mediastinum. Postoperative radiation therapy (PORT) of 45 Gy in 16 fractions over 4 weeks was applied to the entire neck and upper mediastinum using an external X-ray beam. Between 1989-1996, 121 patients with thoracic esophageal carcinoma underwent surgery and received IORT, and 103 of these patients underwent PORT as part of their treatment schedule. RESULTS: The surgical mortality rate was 0.8% (1 of 121 cases). The overall 5-year survival rate was 34.4% and the cause specific 5-year survival rate was 54.8%. The cause specific 5-year survival rate for pN0 tumors was 79.4% and was 43.8% for pN1 tumors. No patients died with locoregional recurrence in the mediastinal lymph nodes. Recurrent laryngeal nerve palsy was observed in 25 patients (21%), but the palsy remained for > 1 month in only 13 patients (11%). Mechanical ventilation support for > 48 hours was required for 22 patients (18.2%). Fatal tracheal ulcers occurred in 4 of 18 patients who received the highest IORT dose of 25 Gy. CONCLUSIONS: Three-field lymphadenectomy to preserve recurrent laryngeal nerves and IORT using 12-20 Gy followed by 45-Gy PORT effectively reduced locoregional recurrence, recurrent laryngeal nerve palsy, and pulmonary complications caused by radical surgical dissections. The minimally effective dose of IORT appears to be < or = 15 Gy, a factor that will be further evaluated with longer follow-up.

Adult↗
PubMed1999

Toxicological significance in the cleavage of esterase-beta-glucuronidase complex in liver microsomes by organophosphorus compounds.

Egasyn is an accessory protein of beta-glucuronidase (beta-G) in the liver microsomes. Liver microsomal beta-G is stabilized within the luminal site of the microsomal vesicles by complexation with egasyn which is one of the carboxylesterase isozymes. We investigated the effects of organophosphorus compounds (OPs) such as insecticides on the dissociation of egasyn-beta-glucuronidase (EG) complex. The EG complex was easily dissociated by administration of OPs, i.e. fenitrothion, EPN, phenthionate, and bis-beta-nitrophenyl phosphate (BNPP), and resulting beta-G dissociated was released into blood, leading to the rapid and transient increase of plasma beta-G level with a concomitant decrease of liver microsomal beta-G level. In a case of phenthionate treatment, less increase in plasma beta-G level was observed, as compared with those of other OPs. This may be explained by the fact that phenthionate was easily hydrolyzed by carboxylesterase. Similarly, carbamate insecticides such as carbaryl caused rapid increase of plasma beta-G level. In contrast, no significant increase of plasma beta-G level was observed when pyrethroid insecticides were administered to rats. This is due to the fact that pyrethroids such as phenthrin and allethrin were easily hydrolyzed by A-esterase as well as carboxylesterase. On the other hand, addition of OPs to the incubation mixture containing liver microsomes caused the release of beta-G from microsomes to the medium. From these in vivo and in vitro data, it is concluded that increase of the plasma beta-G level after OP administration is much more sensitive biomarker than cholinesterase inhibition to acute intoxication of OPs and carbamates.

Animals↗
PubMed1999

Assessment of DNA-protein crosslinks in the course of aging in two mouse strains by use of a modified alkaline filter elution applied to whole tissue samples.

Two different mouse strains have been used for determination of age dependence of DNA-protein crosslinks by alkaline filter elution: a long lived laboratory strain, NMRI and an accelerated senescence-prone, short lived strain, SAMP1. Five organs were selected: Brain, kidney, lung, heart and liver. Remarkably in all five organs of short lived SAMPI mice crosslinks increased significantly with age. In NMRI however only in brain and heart a significant rise in old age has been observed, while in the other organs there was no increase in DNA-protein crosslinking. Appreciable mitotic activity which is lacking in brain and heart could be the reason for this difference. Poor repair in all five organs could be an important component for the multiple ailments and shortened life span in SAMP1 mice.

Aging↗
PubMed1999

Expression of the c-fos gene induced by parathyroid hormone in the bones of SAMP6 mice, a murine model for senile osteoporosis.

SAMP6 mice are a murine model for senile osteoporosis, characterized by low peak bone mass seen at 4 or 5 months of age. Parathyroid hormone (PTH)-induced c-fos expression was examined in the bones, bone-marrow cells and kidney tissues of 2-month-old male SAMP6 mice. SAMP2 mice, which have a higher peak bone mass, were used as controls. The expression of c-fos in the bone peaked at 30 min after 60 microg/kg of human PTH(1-34) administration. After peaking, the expression fell quickly in SAMP2 mice. This decrease in expression was delayed in SAMP6 mice and the expression was higher at 1 h than in SAMP2 mice. The phenomenon observed in the bone appears to be tissue specific as it was not seen in the bone-marrow cells or kidney tissue. Immunohistochemical studies showed that c-Fos protein was localized to the nuclei of some of the osteocytes and a few of the osteoblasts in the cortical bone, and that osteocytes expressing c-Fos protein increased after PTH treatment. These results suggest that osteocytes might contribute to the maintenance of higher levels of c-fos expression in the bones of SAMP6 mice and may be related to cortical osteopenia in these mice by modulating bone remodeling and/or modeling.

Animals↗
PubMed1999

Increased E1AF expression in mouse fibrosarcoma promotes metastasis through induction of MT1-MMP expression.

In this study, we investigated the role of E1AF, a member of ets family transcription factor, in the acquisition of metastatic capacity by non-metastatic mouse fibrosarcoma cell clone, QR-32. The QR-32 cell clone grows progressively after co-implantation with gelatin sponge in syngeneic C57BL/6 mice. The cell lines (QRsP) established from arising tumors after the co-implantation exhibited enhanced tumorigenicity and pulmonary metastasis in vivo as compared with parent QR-32 cells. The enhanced pulmonary metastasis of QRsP cells was correlated well with augmented production of matrix metalloproteinase-2 (MMP-2) and increased expression of membrane-type 1-MMP (MT1-MMP). The QRsP cells also acquired higher chemokinetic activities to fibronectin and higher invasive activities through a reconstituted basement membrane. Furthermore we observed the elevated mRNA expression of E1AF in QRsP cells compared to parent QR-32 cells. Therefore, we transfected QR-32 cells with E1AF cDNA. Overexpression of E1AF in the QR-32 cells resulted in the induction of MT1-MMP expression and converting an exogenously added precursor MMP-2 into active form. E1AF transfectants exhibited more motile and invasive activities, and moderately increased pulmonary metastatic activities than parental QR-32 cells in vivo, although their metastatic activities were lower than those of QRsP cells. These findings suggest that the increased expression of E1AF in fibrosarcoma contributes to invasive phenotypes including MT1-MMP expression and enhanced cell migration, but not sufficient for exhibiting highly metastatic activity in vivo.

Adenovirus E1A Proteins↗
PubMed1999

Selective transendothelial migration of hematopoietic progenitor cells: a role in homing of progenitor cells.

To elucidate the mechanisms by which hematopoietic progenitor cells transmigrate via the bone marrow (BM) endothelial cells, we first established endothelial cell lines from BM and lung, and BM fibroblast cell lines; then we established an in vitro model of transendothelial migration of hematopoietic progenitor cells in the presence of chemoattractants secreted by BM fibroblast cells. The BM endothelial cells expressed vascular cell adhesion molecule-1 (VCAM-1), but the lung endothelial cells did not. The BM fibroblast cells secreted chemoattractants including stroma cell-derived factor (SDF)-1, which could attract hematopoietic progenitor cells to BM and activate the adhesion molecules expressed on hematopoietic progenitor cells after rolling along the endothelial cells. Anti-SDF-1 antibody inhibited the transendothelial migration of a hematopoietic progenitor cell line, FDCP-2. FDCP-2 that expressed very late activation antigen-4 (VLA-4) and normal progenitor cells transmigrated through BM endothelial cells but not lung endothelial cells, even if in the presence of chemoattractants produced by BM fibroblasts. Both anti-VLA-4 and anti-VCAM-1 antibodies inhibited the transendothelial migration of FDCP-2 cells and normal hematopoietic progenitor cells. These findings suggest that the transendothelial migration of hematopoietic progenitor cells is characteristic of BM endothelial cells, and that VLA-4/VCAM-1 and SDF-1 play important roles in the transendothelial migration and, consequently, homing of hematopoietic progenitor cells to BM.

Animals↗
PubMed1999

"Neuro-sweet disease": benign recurrent encephalitis with neutrophilic dermatosis.

OBJECTIVE: To describe benign recurrent encephalitis in a case of Sweet syndrome that also showed clinical features of Behçet disease. CASE REPORT: A 37-year-old Japanese man developed relapsing and remitting encephalitis and mucocutaneous symptoms mimicking Behçet disease. Magnetic resonance images showed at least 5 episodes of transient abnormal signal intensity in various cerebral regions over a period of 5 years. A skin biopsy specimen of the cutaneous edematous erythematous plaques revealed neutrophilic dermatitis compatible with Sweet syndrome. HLA typing showed B54, which is frequent in Sweet syndrome but rare in Behçet disease. Oral prednisolone therapy (10-60 mg/d) was remarkably effective for the encephalitis as well as for the mucocutaneous symptoms. CONCLUSION: We propose that there is an entity that is like Sweet disease, but with recurrent encephalitis characterized by an association with HLA-B54 and a high responsiveness to corticosteroid therapy, which we have tentatively named neuro-Sweet disease, that is distinct from the classic central nervous system involvement of Behçet disease.

Adult↗
PubMed1999

Identification of peak bone mass QTL in a spontaneously osteoporotic mouse strain.

The whole genome scan for quantitative trait loci (QTLs) specifying peak bone mass was performed with the F2 intercrosses of SAMP6, an established murine model of senile osteoporosis, exhibiting a significantly lower peak bone mass, and SAMP2, exhibiting a higher peak bone mass. Cortical thickness index (CTI), a parameter of bone mass of femurs, was measured in 488 F2 progeny at 4 months of age, when the animals attained peak bone mass by microphotodensitometry. Genetic markers were typed at 90 loci spanning all chromosomes except the Y. By interval mapping of 246 male F2 mice, two loci were identified with significant linkage to peak bone mass, one on Chromosome (Chr) 11 and another on Chr 13, with a maximum lod score of 10.8 (22.2% of the total variance) and 5.8 (10.0%), respectively. Another locus on the X Chr was suggestive of a QTL associated oppositely with a low peak bone mass to the SAMP2 allele. This association was consistent with the distribution of peak bone mass in the F1 and F2. These findings should be useful to elucidate the genetics of osteoporosis.

Animals↗
PubMed1999

Genetic typing of the senescence-accelerated mouse (SAM) strains with microsatellite markers.

The Senescence-Accelerated Mouse (SAM) strains constitute a murine model of accelerated senescence originating from the ancestral AKR/J strains and consist of nine senescence-prone (SAMP) strains and four senescence-resistant (SAMR) strains. The chromosomes (Chrs) of the SAM strains were typed with 581 microsatellite markers amplified by PCR, and the fundamental genetic information of the SAM strains was obtained. One-third of the examined markers displayed polymorphism among the strains, and only two alleles were detected in almost all loci among the SAM and AKR/J strains. However, in 12 loci (5.6% of total 215 polymorphic markers), the third allele was detected among the SAM strains. The genetic typing and developmental history suggested that the SAM strains were related inbred strains developed by the accidental crossing between the AKR/J strain and other unknown strain(s). Comparison of the distribution of the loci in the SAMP and the SAMR series revealed notable differences in the four regions on Chrs 4, 14, 16, and 17. This indicated that some of these chromosomal sites might contain the genes responsible for accelerated senescence in the SAMP series.

Aging↗
PubMed1999

The passage of blood-borne horseradish peroxidase into the amygdaloid area of the mouse brain.

The passage of blood-borne horseradish peroxidase (HRP) into the amygdaloid area of the mouse brain was examined with light and electron microscopy. Staining reaction for HRP appeared in medial portions of the amygdaloid area, especially adjacent to the optic tract. Ultrastructural examination of some vessels in that area revealed that the staining reaction for HRP appeared in the perivascular space, the basal lamina, the cytoplasm or vesicular structures of the perivascular cells, vesicular profiles of the endothelial cell cytoplasm including abluminal pits and the adjacent extracellular space. These findings suggest that intravascular macromolecules can invade medial portions of the amygdaloid area of the mouse brain.

Amygdala↗
PubMed1999

Mouse senile amyloid deposition is suppressed by adenovirus-mediated overexpression of amyloid-resistant apolipoprotein A-II.

Apolipoprotein A-II (apoA-II), the second most abundant apolipoprotein of serum high density lipoprotein, deposits as an amyloid fibril (AApoAII) in old mice. Mouse strains with a high incidence of senile amyloidosis have the type C apoA-II gene (Apoa2(c)), whereas the strains with a low incidence of amyloidosis have the type B apoA-II gene (Apoa2(b)). In this study, to investigate whether the type B apoA-II protein inhibits the extension of amyloid fibrils, we constructed an adenovirus vector bearing the Apoa2(b) cDNA (Adex1CATApoa2(b)), which is expressed under the control of a hepatocyte-specific promoter. The mice were infected with Adex1CATApoa2(b) before induction of amyloidosis by the injection of AApoAII amyloid fibril seeds. Compared with the mice infected with the control virus, amyloid deposition was suppressed significantly in the mice infected with Adex1CATApoa2(b). Fluorometry using thioflavine T also revealed that AApoAII fibril extension was inhibited by the addition of type B apoA-II in vitro. Thus, we propose that Apoa2(b) contributes as an active inhibitor of amyloid fibril extension and overexpression of amyloid-resistant gene variant may be an attractive therapeutic target in amyloidosis.

Adenoviridae↗
PubMed1999

Adrenomedullin promotes epithelial restitution of rat and human gastric mucosa in vitro.

We have investigated the effect of adrenomedullin (AM) on restitution of mucosal integrity following damage in rat and human gastric mucosa, measuring the potential difference (PD) on a mucosal strip mounted on an Ussing chamber. Mucosal damage was induced by 0.5, 1.0, and 2.0 M NaCl solution, and it caused an immediate and significant decrease in PD. In the rat AM group, PD recovered significantly more than in control group at 120 min after exposure to 0.5 M (p < 0.01) and 1.0 M (p < 0.05) NaCl solution. In the human AM group, PD completely recovered at 120 min after exposure to 0.5 M (p < 0.05) NaCl solution. In rat mucosa damaged by 0.5 M NaCl solution, the effect was inhibited by human (h)-CGRP(8-37) and there was no significant difference between the h-CGRP(8-37) group and control group. On immunohistochemical examination of rat gastric mucosa, AM was detected within the chief cell. AM probably promotes epithelial restitution primarily through the CGRP receptor, but it does not ameliorate more severe damage of gastric mucosa in vitro.

Adrenomedullin↗
PubMed1999

Age-associated changes in elastin and collagen content and the proportion of types I and III collagen in the lungs of mice.

We investigated the effect of aging on the extracellular matrix of the lungs by examining age-associated changes in the elastin and collagen content, and the proportion of types I and III collagen, in the whole lungs of BALB/c and SAMR1 male mice between the ages of 3 and 24 months. The elastin content was determined by the hot alkali method. The hydroxyproline content was measured and assessed to be the collagen content. The relative proportion of types I and III collagen was assessed by cyanogen bromide digestion, followed by separation of the resultant peptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The elastin content did not change significantly with age in either strain of mice. The total collagen content of the whole lung was significantly higher at 24 months of age, although there were no significant changes with aging in the hydroxyproline content per dry lung weight nor in the proportion of type III to type I collagen. We conclude that in terms of the extracellular matrix, the lungs of aged mice are not very different in feature from the lungs of younger mice, and this is probably the simple consequence of growth of the lungs of young mice.

Aging↗
PubMed1999

Inflammatory cell-mediated tumour progression and minisatellite mutation correlate with the decrease of antioxidative enzymes in murine fibrosarcoma cells.

We isolated six clones of weakly tumorigenic fibrosarcoma (QR) from the tumorigenic clone BMT-11 cl-9. The QR clones were unable to grow in normal C57BL/6 mice when injected s.c. (1x10(5) cells). However, they formed aggressive tumours upon co-implantation with a 'foreign body', i.e. a gelatin sponge, and the rate of tumour take ranged from 8% to 58% among QR clones. The enhanced tumorigenicity was due to host cell-mediated reaction to the gelatin sponge (inflammation). Immunoblot analysis and enzyme activity assay revealed a significant inverse correlation between the frequencies of tumour formation by QR clones and the levels of manganese superoxide dismutase (Mn-SOD, P<0.005) and glutathione peroxidase (GPchi, P<0.01) in the respective tumour clones. Electron spin resonance (ESR) revealed that superoxide-scavenging ability of cell lysates of the QR clone with high level of Mn-SOD was significantly higher than that with low level of the antioxidative enzyme in the presence of potassium cyanide, an inhibitor for copper-zinc superoxide dismutase (CuZn-SOD) (P<0.001). Minisatellite mutation (MSM) induced by the inflammatory cells in tumour cells were investigated by DNA fingerprint analysis after QR clones had been co-cultured with gelatin-sponge-reactive cells. The MSM rate was significantly higher in the subclones with low levels of Mn-SOD and GPchi (P<0.05) than in the subclones with high levels of both enzymes. The MSM of the subclones with low levels of both enzymes was inhibited in the presence of mannitol, a hydroxyl radical scavenger. The content of 8-hydroxydeoxyguanosine (8-OHdG) by which the cellular DNA damage caused by active oxygen species can be assessed was significantly low in the tumours arising from the QR clone with high levels of Mn-SOD and GPchi even if the clone had been co-implanted with gelatin sponge, compared with the arising tumour from the QR clone with low levels of those antioxidative enzymes (P<0.001). In contrast, CuZn-SOD and catalase levels in the six QR clones did not have any correlation with tumour progression parameters. These results suggest that tumour progression is accelerated by inflammation-induced active oxygen species particularly accompanied with declined levels of intracellular antioxidative enzymes in tumour cells.

Animals↗
PubMed1999

Selective secretion of chemoattractants for haemopoietic progenitor cells by bone marrow endothelial cells: a possible role in homing of haemopoietic progenitor cells to bone marrow.

To elucidate the mechanisms by which haemopoietic progenitor cells lodge in the bone marrow, we examined the secretion of chemoattractants for haemopoietic progenitor cells by bone marrow and lung endothelial cells. The bone marrow endothelial cells, but not lung endothelial cells, secreted chemoattractants for the haemopoietic progenitor cell line, FDCP-2, and normal haemopoietic progenitor cells. Checkerboard analysis demonstrated that the conditioned medium of the bone marrow endothelial cells had chemotactic activity and random motility-stimulating activity. The bone marrow endothelial cells expressed stromal-cell-derived factor-1 (SDF-1) mRNA and produced SDF-1 protein, whereas the lung endothelial cells did not. Adhesion of FDCP-2 cells to the bone marrow endothelial cells was partially inhibited by anti-SDF-1 antibody. These findings suggest that the chemoattractants for haemopoietic progenitor cells including SDF-1 and random motility-stimulating factor(s) selectively secreted by the bone marrow endothelial cells may contribute to the homing of haemopoietic progenitor cells to bone marrow.

Animals↗