Biomedical subjects

S Sakuma

Publications and source records attributed to S Sakuma.

At least 91 records · Page 5Linked to original sources

PubMed1998

Genetics of susceptibility to radiation-induced apoptosis in colon: two loci on chromosomes 9 and 16.

Apoptosis, a mechanism for removal of genetically damaged cells and for maintenance of desired size of cell populations, has been implicated in tumor development. Previously, we defined polymorphic loci for susceptibility to apoptosis of thymocytes Rapop1, Rapop2, and Rapop3 on mouse Chromosomes 16, 9, and 3, respectively, using recombinant congenic CcS/Dem strains, each of which contains a random set of 12.5% STS/A genome in the genetic background of BALB/cHeA. The STS/A alleles at these loci confer lower susceptibility to radiation-induced apoptosis of thymocytes than the BALB/cHeA. In the present study, we tested susceptibility of colon crypt cells to radiation-induced apoptosis. In contrast to apoptosis in thymus, the STS/A mice were more susceptible to apoptosis in colon than the BALB/cHeA. Among the CcS/Dem strains, CcS-4, CcS-7, and CcS-16 were more susceptible to apoptosis in colon than the BALB/cHeA; in thymus, the CcS-7 mice are less susceptible, and the CcS-4 and CcS-16 are not different from the BALB/cHeA. Thus, individual CcS/Dem strains showed different apoptosis susceptibility in the two organs. Analysis of (CcS-7 x BALB/cHeA)F2 hybrids revealed linkage of susceptibility to radiation-induced apoptosis of colon crypt cells to two loci on Chrs 9 and 16, to which Rapop2 and Rapop1 are mapped. The STS/A allele at the locus on chromosome 9 results in high susceptibility to apoptosis of colon crypt cells in mice homozygous for the BALB/cHeA allele at the locus on Chr 16. Although these two loci may be identical to Rapop1 and Rapop2, they affect apoptosis in colon in a way different from that in thymus.

Animals↗

PubMed1998

Analysis of aberrant neuronal migrations in the hereditary cerebellar vermis defect (CVD) rat using bromodeoxyuridine immunohistochemistry.

The hereditary cerebellar vermis defect rat (CVD) is a new neurological mutant characterized by cerebellar vermis defect and a dysplastic cerebellum, especially in the cerebello-pontine junctions. In this study, the cytokinetics of neuronal migrations in the CVD were analyzed using 5-bromo-2'-deoxyuridine (BrdU) as a labeling marker. From embryonic day 21, the CVD cerebellum was small in size with retarded foliation, but no significant differences were detected in the migration pattern of the BrdU-labeled cells between the unaffected controls and the CVD during the prenatal period. On postnatal day 0 (P0), heterotopic Purkinje cells, demonstrable by calbindin immunohistochemistry, were seen in the dorsal pons of the CVD. From P4, BrdU-positive external granule cells (EGCs), which were labeled by BrdU injection on P2, began to penetrate the pons. From P5, the EGCs aggregated around the blood vessels, leading to a disturbance of the cerebellar lamination both in the cerebello-pontine junctions and in the cerebellar hemispheres. Thereafter, the BrdU-labeled cells in the perivascularly aggregated EGCs migrated radially, and formed internal granular layers around the vessels, indicating an aberrant perivascular migration of the EGCs. These findings suggest that the EGC dislocation was preceded by an aberrant settlement of the Purkinje cells, and that the perivascularly aggregated EGCs resulted in cerebellar dysplasia in the CVD.

Aging↗

PubMed1998

Relationship between vimentin expressing renal tubules and interstitial fibrosis in chronic progressive nephropathy in aged rats.

We investigated the relationship between regenerating renal tubular epithelial cells and myofibroblast development in chronic progressive nephropathy (CPN) of aged male F344 rats. We used established criteria to classify disease in rats with CPN as grade 1 (n=9), grade 2 (n=10), grade 3 (n=7) and grade 4 (n=4). Five young rats served as controls (grade 0). The ratio of fibrotic tissues per unit area, assessed in collagen type III-immunostained sections by morphometric analysis, increased significantly with advancing grade of CPN. Vimentin-expressing, regenerating renal tubules were found from grade 1 and continued to increase in number up to grade 3, decreasing slightly, however, in grade 4. Similar kinetics were seen for the number of alpha-smooth muscle actin-positive myofibroblasts, and there was a significant correlation between the number of regenerating renal tubules and myofibroblast development (correlation coefficient=0.83, P<0.01). The myofibroblasts developed in close association with the fibrotic areas seen in grades 1-4; the cells also reacted to desmin or vimentin, indicating the activated state. Immunohistochemistry for platelet-derived growth factor (PDGF)-BB and transforming growth factor (TGF)-beta revealed that vimentin-positive renal tubules were positive for PDGF-BB, but negative for TGF-beta, and that interstitial reactive cells showed no positive reactions for both factors. The present studies on rat CPN showed that regenerating renal tubules may be a major source of a fibrogenic growth factor, PDGF-BB, and that the PDGF-BB might induce the development of fibrogenic cells, myofibroblasts, culminating in progressive interstitial fibrosis.

Actins↗

PubMed1998

Adhesive activity of gicerin, a cell-adhesion molecule, in kidneys and nephroblastomas of chickens.

Gicerin, a cell-adhesion molecule belonging to the immunoglobulin superfamily, has both homophilic and heterophilic binding activities to neurite outgrowth factor, an extracellular matrix molecule in the laminin family. Gicerin is thought to play a role in the normal development of chicken kidney, because it is expressed abundantly in the embryonic organ and only slightly in the mature organ. In this study, we have examined the adhesive activity of gicerin in the kidney to characterize its function in organogenesis. We have also examined the function of gicerin in chicken nephroblastomas ("embryonic nephromas"), which show various structures resembling those in embryonic kidneys. Immunohistochemically, the expression patterns of gicerin and neurite outgrowth factor in nephroblastomas are similar to those of embryonic kidneys. Cell-aggregation assays have shown that primary culture cells from both embryonic kidneys and nephroblastomas have strong aggregation activities, and that each aggregation is partially inhibited by gicerin antibody. In contrast, cells from adult kidney exhibit weak aggregation activity that is not inhibited by the antibody. In addition, ligand blot analysis has revealed that gicerins in embryonic kidney and nephroblastoma bind to purified neurite outgrowth factor, whereas extracts from adult kidney show no positive reaction. These findings suggest that the homophilic and heterophilic adhesive activities of gicerin are involved in the formation of both normal kidney and nephroblastoma.

Animals↗

PubMed1998

Influence of progesterone and oestrogen on growth and morphology of a transplantable rat uterine smooth muscle tumour (SMT-Y).

Tumours of uterine smooth muscle are poorly understood neoplasms in which the effects of steroid sex hormones are complex. The influence of progesterone and oestrogen on a transplantable rat uterine smooth muscle tumour line (SMT-Y) was investigated. Female F344 rats given subcutaneous transplants of tumour fragments developed tumours, 1.5-2 cm in diameter, and were then treated with progesterone (10 mg/rat) or 17 beta-oestradiol (50 mg/rat). Tumours in treated groups were compared with those in untreated controls. During a 9-week observation period after treatment, progesterone promoted tumour growth from 4 weeks, with increased numbers of proliferating cells. In contrast, oestradiol inhibited tumour growth from 6 weeks; the degraded tumours, consisting mainly of vacuolated neoplastic cells, had decreased numbers of proliferating cells and increased numbers of apoptotic cells, demonstrable by in-situ terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick labelling. Immunohistochemically, tumours in control and progesterone groups were labelled positively for alpha-smooth muscle actin (SMA) and desmin but not for vimentin, whereas the degraded tumours in the oestradiol group had reduced reactivity for SMA and desmin but an increased reactivity for vimentin. These results indicate that progesterone may act as a promoter for uterine smooth muscle tumour growth by stimulating mitotic activity, whereas oestrogen may have suppressive effects on tumour growth, accompanied by morphological changes.

Animals↗

PubMed1998

Neurite promotion from ciliary ganglion neurons by gicerin.

Gicerin is a cell adhesion molecule of an immunoglobulin superfamily member and transiently expressed on the surface of neurons such as retinal ganglion cells during synaptogenesis. Gicerin is a receptor for NOF (neurite outgrowth factor) that belongs to the laminin family, and mediates neurite extension induced by NOF. As we have reported, gicerin also exhibits homophilic cell adhesion activity, we compared the patterns of extending neurites induced by homophilic and heterophilic cell adhesion activities of gicerin using ciliary ganglion (CG) neurons. CG neurons expressed gicerin and extended neurites on a feeder layer of gicerin-transfected cells, suggesting a neurite extension by gicerin-gicerin (homophilic) interaction. We found that CG neurons cultured on gicerin-transfected cells extended slightly branched neurites, while those cultured on NOF-coated substratum extended many long branched neurites. It is suggested that neurites induced by homophilic or heterophilic cell adhesion activities of gicerin differ in the length and branching.

Animals↗

PubMed1998

Comparison of the effects of nitric oxide and peroxynitrite on the 12-lipoxygenase and cyclooxygenase metabolism of arachidonic acid in rabbit platelets.

The effects of a new type of nitric oxide (NO)-releasing compound, 1-hydroxyl-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene (NOC7), and peroxynitrite (ONOO-) on the formation of 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE), thromboxane (TX) B2 and 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) from exogenous arachidonic acid in washed rabbit platelets have been compared. At concentrations of 5 microM and below, NOC7 inhibited 12-HETE formation (56.5-98.8% inhibition). Moreover, NOC7 inhibited TXB2 and HHT formation at concentrations ranging from 5 to 20 microM (TXB2, 62.2-88.1% inhibition; HHT, 11.6-62.2% inhibition). ONOO- had little or no effect on the production of these three metabolites at concentrations of up to 50 microM. Experiments utilizing a new class of NO antidote, carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide, revealed that the observed effects of NOC7 are caused by NO. The effects of NO were reversed by addition of the superoxide generating system (xanthine plus xanthine oxidase and catalase), indicating that superoxide is a vital modulator of the action of NO. These results suggest that NO, but not ONOO- (up to 50 microM), can be a potent dual inhibitor of the 12-lipoxygenase and cyclooxygenase activities in platelets and that superoxide is an important regulator of the action of NO.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1998

Effects of daphnodorin A, B and C, new flavans isolated from traditional Chinese medicine, on the 12-lipoxygenase and cyclooxygenase metabolism of arachidonic acid in rabbit platelets.

The effects of daphnodorin A, B and C, isolated from the root and bark of Daphne odora THUNB, on the activities of 12-lipoxygenase and cyclooxygenase in rabbit platelets were examined. Daphnodorin A and C were inhibitors of platelet 12-lipoxygenase and cyclooxygenase activities. Daphnodorin B had no effect on the two enzymatic pathways. The present data raise the possibility that daphnodorin A and C can be anti-thrombotic and anti-atherosclerotic drugs through the suppressive influence on the platelet 12-lipoxygenase and cyclooxygenase.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1998

Human astrocytoma cells are capable of producing macrophage inflammatory protein-1beta.

We investigated expression of macrophage inflammatory protein-1 (MIP-1) alpha and beta in human astrocytoma cell lines and surgical specimens of astrocytic tumors. Enzyme-linked immunosorbent assay (ELISA) showed constitutive secretion of MIP-1alpha protein in only one and MIP-1beta in none of 7 cell lines tested. However, MIP-1alpha production was increased in three cell lines by stimulation with lipopolysaccharide (LPS) and 5 cell lines by stimulation with phorbol-12myristate-13-acetate (PMA). Also, induction of MIP-1beta production was observed in one cell line with LPS stimulation and in two cell lines with PMA stimulation. Reverse-transcription polymerase chain reaction (RT-PCR) showed the increase of MIP-1alpha and beta mRNA expression in these cell lines. The increase of the mRNA with the stimuli was further confirmed by Northern blot analysis. In contrast, RT-PCR analysis revealed that the majority of the tested tumor specimens of high-grade.astrocytomas expressed both MIP-1alpha and MIP-1beta mRNAs. ELISA detected MIP-1beta protein in 1 of 11 cerebrospinal fluid samples from patients with high-grade astrocytoma and in 8 of 9 tumor cyst fluid samples, whereas MIP-1alpha was detected in only 1 cyst fluid somple. Taken together, these results indicate that astrocytic tumor cells are capable of expressing and producing MIPs, and suggest that MIPs may participate in the inflammatory responses commonly seen in astrocytic tumors.

Astrocytoma↗

PubMed1998

Monitoring adenoviral p53 transduction efficiency by yeast functional assay.

Monitoring the transduction efficiency is of paramount importance in gene therapy. To monitor adenovirus-mediated wild-type p53 gene transfer, we have used a quantitative assay which tests the ability of human p53 to activate transcription in yeast. Selective amplification of cellular and viral p53 transcripts followed by quantitative assessment of mutant p53 content with the assay permits measurement of the wild-type p53 transduction efficiency into SF-188, U251MG and HUG31 glioblastoma cells. One reverse transcription primer tracks the wild-type/mutant ratio of endogenous p53 mRNA (P2), and the other the wild-type/mutant ratio of both endogenous and exogenous p53 mRNA (P1). Following infection of cell lines homozygous for mutant p53, the apparent transduction efficiency calculated (tau 0 = [P1-P2]/[1 + P2]) correlated with the level of p21 expression. Transduction efficiency in heterozygous wild-type/mutant HUG31 cells increased linearly with multiplicity of infection (MOI) for tau 0 values between 0.5 and 5.9, and admixture of normal cell-derived RNA produced only a modest reduction in tau 0 value, in keeping with theoretical predictions. These results suggest that the yeast p53 functional assay may be a useful tool for monitoring p53 gene therapy.

Adenoviridae↗

PubMed1998

Effects of eicosapentaenoic acid and its 15-hydroperoxy and 15-hydroxy derivatives on glucosamine synthetase activity in rabbit gastric mucosa.

The effects of eicosapentaenoic acid and its 15-hydroperoxy and 15-hydroxy adducts on the activity of glucosamine synthetase, the rate-limiting enzyme of mucus synthesis, in rabbit gastric antral mucosa were examined. 15-Hydroperoxy-eicosapentaenoic acid inhibited the glucosamine synthetase activity at concentrations of 10, 20 and 50 microM. The effect was concentration-dependent, and the concentration required for 50% inhibition was approximately 20 microM. Eicosapentaenoic acid and its 15-hydroxy adduct had no significant effect on the enzyme activity at the same concentration range. The experiment utilizing Fe2+ revealed that the inhibitory effect of 15-hydroperoxyeicosapentaenoic acid on the glucosamine synthetase activity is not due to hydroxy radical which is expected to be formed from the hydroperoxy adduct. These results suggest that 15-hydroperoxyeicosapentaenoic acid has the potential to reduce the synthesis of gastric mucus by inhibiting the glucosamine synthetase activity.

Animals↗

PubMed1998

Inhibition of 15-hydroxyprostaglandin dehydrogenase activity in rabbit gastric antral mucosa by panaxynol isolated from oriental medicines.

Panaxynol is a polyacetylene compound with anti-inflammatory and anti-platelet-aggregatory effects isolated from commonly used oriental medicines. The effects of panaxynol on the activity of prostaglandin-synthesizing and catabolizing enzymes in the rabbit gastric antral mucosa have been examined. At concentrations ranging from 25 to 200 microM panaxynol had no effect on the synthesis of prostaglandins E2, F2alpha and D2 from exogenous arachidonic acid in the microsomal fraction of the gastric mucosa whereas at 25-200 microM it dose-dependently inhibited the activity of 15-hydroxyprostaglandin dehydrogenase (PGDH), which catalyses the initial step of prostaglandin catabolism, in the cytosolic fraction. The concentration required for 50% inhibition (IC50) was approximately 25 microM. Inhibition of PGDH by panaxynol was non-competitive with regard to NAD+ and prostaglandin E2. These results suggest that panaxynol has the potential to inhibit PGDH activity in gastric mucosa, possibly as a result of pharmacological activity.

Alkynes↗

PubMed1998

Analysis of quinolone resistance mechanisms in Neisseria gonorrhoeae isolates in vitro.

BACKGROUND AND OBJECTIVES: Gonococcal fluoroquinolone resistance is now a significant problem in Japan. We generated gonococcal mutants resistant to norfloxacin in vitro from norfloxacin sensitive isolates and analysed the contribution of three known mechanisms of quinolone resistance in Neisseria gonorrhoeae. MATERIALS AND METHODS: Three clinical isolates of N gonorrhoeae susceptible to norfloxacin were exposed to increasing concentrations of norfloxacin. To identify mutations in the gyrA and parC genes of the gonococcal mutants, the quinolone resistance determining regions of the gyrA and parC genes were polymerase chain reaction (PCR) amplified and the PCR products were directly sequenced. Norfloxacin accumulation in the gonococcal cells was also measured. RESULTS: The MICs of norfloxacin for three variants containing a single GyrA mutation were 16-fold higher than that for their parent isolates. A variant showing reduced norfloxacin accumulation in the cells, without mutations in the GyrA or ParC proteins, was also less sensitive to norfloxacin, with a 16-fold increase in the MIC, compared with the parent strain. The MIC of norfloxacin for a variant which contained a single GyrA mutation with reduced norfloxacin accumulation in the cells was 128-fold higher than for the parent strain. A variant containing mutations in both GyrA and ParC proteins with reduced accumulation of norfloxacin in the cells showed a 256-fold increase in the norfloxacin MIC compared with the parent strain. There was no variant containing a ParC mutation without the simultaneous presence of a GyrA mutation. CONCLUSIONS: The results from this study suggest that not only a mutation in the gyrA gene but also reduced drug accumulation in cells contributes to the development of fluoroquinolone a mutation in the gyrA gene contributes to a high level of fluoroquinolone resistance in gonococci with decreases in accumulation in cells having an additional but lesser effect.

Anti-Infective Agents↗

PubMed1998

Canine peripheral nerve sheath tumor with eosinophilic cytoplasmic globules.

A 13-year-old male Shetland Sheepdog had a subcutaneous tumor in the left brachium. The tumor was removed and recurred several times at 5, 13, 16, 22, and 31 months after the initial presentation. Histologically, the removed nodules from the fourth resection were composed of neoplastic proliferation of round to fusiform cells, which possessed eosinophilic globules in their cytoplasm. The globules were periodic acid-Schiff positive and diastase resistant. Positive reactions for acid phosphatase were observed in the cytoplasm of the tumor cells. Ultrastructurally, these globules consisted of membrane-bound, dense structures containing dense granules, lucent vacuoles, and homogeneous materials. The recurrent tumors removed at the fifth resection consisted of spindle cell proliferation arranged in interlacing fascicles with wavy nuclei and containing a small number of cells with cytoplasmic globules. The tumor cells were immunoreactive to vimentin, S-100 protein, myelin basic protein, and neuron-specific enolase. The tumor was diagnosed as a peripheral nerve sheath tumor with eosinophilic cytoplasmic globules. These findings are unique for the histogenesis of granular cell tumors.

Animals↗

PubMed1998

Macrophages, myofibroblasts, and extracellular matrix accumulation in interstitial fibrosis of chronic progressive nephropathy in aged rats.

Progressive renal fibrosis is considered to be the final common pathway leading to chronic renal failure. Macrophages are thought to play a role in the induction of the myofibroblasts that produce extracellular matrix (ECM) proteins in renal interstitial fibrosis. We immunohistochemically investigated the relationship between infiltrating macrophages and myofibroblast development in chronic progressive nephropathy (CPN) in 24 month-old male F344 rats, and we also analyzed components of ECM proteins using immunofluorescence microscopy. According to histomorphologic criteria for severity, described elsewhere, rats with CPN were divided into grade 1 (n = 20), grade 2 (n = 34), grade 3 (n = 10), and grade 4 (n = 6). The ratio of fibrotic tissues per unit area, determined by morphometric analysis, was increased with advancing grade of nephropathy. The number of interstitial macrophages continued to be increased gradually, with a peak in grade 4. Alpha-smooth muscle actin-positive myofibroblasts developed, surrounding the regenerating renal tubules in conjunction with the fibrotic areas. The number of the myofibroblasts was also increased, with a peak in grade 3, but in grade 4, it was slightly decreased. There was a significant relationship between the number of infiltrating macrophages and the degree of interstitial fibrosis (r = 0.802; P < 0.05). These observations suggest that macrophages and myofibroblasts might be key cells in fibrogenesis in CPN. However, there was no significant correlation between the numbers of macrophages and myofibroblasts (r = 0.198; P > 0.05), although a significant relation between these cells has been reported in the early stages of experimental rat renal fibrosis. Immunostaining for collagen type IV demonstrated increased expression in thickened tubular basement membranes. Abnormal depositions of collagen types I and III, fibronectin, and tenascin were also observed in fibrotic areas adjacent to dilated or atrophic tubules with thickened basement membranes. These ECM proteins were increased in conjunction with the grade of nephropathy, suggesting that ECM accumulation might contribute to progression of renal interstitial fibrosis.

Actins↗

PubMed1998

[Effects of tacrolimus ointment on type I (immediate and late) and IV (delayed) cutaneous allergic reactions in mice].

The effects of tacrolimus ointment on immediate, late and delayed-type cutaneous allergic reactions and normal skin thickness were investigated in mice and compared with those of steroid ointments. Tacrolimus ointment had no effect on ear edema in the immediate phase of the biphasic reaction and did not inhibit passive cutaneous anaphylaxis, but in the late phase of the biphasic reaction, it inhibited the ear edema. It also showed a clear inhibitory effect on the delayed-type reaction. These evidence suggest that the clinical effect of tacrolimus ointment against atopic dermatitis (AD) may be mainly due to its inhibitory action on late and delayed-type reactions. The steroid ointments inhibited all the reactions mentioned above, and the effects were more potent than those of tacrolimus. Moreover, they also decreased the normal ear thickness, suggesting that the inhibitory effect of the steroid ointments was partially due to skin atrophic action. The same ointments applied to the ears during the induction phase showed an enhancement of delayed-type reaction at the effector phase. Tacrolimus ointment did not show such a rebound effect or skin atrophy. Thus, tacrolimus ointment was expected to be more useful than the steroids for the treatment of AD.

Animals↗

PubMed1998

Frequent expression of the c-kit proto-oncogene in canine malignant mammary tumor.

The mammary tumor is one of the popular neoplastic diseases in female dogs. In the present study, the expression of canine c-kit proto-oncogene in mammary tumor specimens was investigated to evaluate its potential usefulness as a tumor marker. By comparing the homology among the nucleotide sequences reported for human mouse, rat and feline c-kit c-DNA, a pair of primers was synthesized for the reverse transcriptase-polymerase chain reaction (RT-PCR) method. The RT-PCR product of canine spleen total RNA was shown to have 756 bp in size and to be highly homologous to the corresponding sequences reported for the mammalian species. The expression of c-kit transcript was detected in 11 mammary tumors of different histopathology including adenocarcinomas, benign and malignant mixed tumors. The level of the transcription in adenocarcinomas was significantly higher than those in malignant mixed tumors. Fifteen canine tumor specimens originated from various tissues were also tested for their c-kit transcript. In all of the mastocytoma samples examined, high expression of the mRNA was detected. Of other 12 tumors, only low level of RT-PCR products were detected in 5 samples, whereas no apparent amplification was observed in 7 tumors. These results indicate that the high expression of c-kit transcript is helpful for the diagnosis of canine mammary tumors.

Animals↗

PubMed1998

C-cell adenoma containing variously sized thyroid follicles in a horse.

A thyroid gland tumor, showing unusual histology, was identified in a 13-year-old male Andalusian horse. Microscopically, the tumor consisted of neoplastic proliferation of C-cell (parafollicular cell) with cytoplasmic fine granules, containing diffusely distributed, variously sized colloid-containing follicles. Immunohistochemically, the neoplastic C-cell were positive for calcitonin and follicleforming epithelial cells showed a positive reaction for thyroglobulin. Ultrastructurally, membrane-bound secretory granules up to 250 nm in diameter were found in the cytoplasm of the parafollicular cells, whereas the follicular epithelial cells had microvilli, junctional complex, and well-developed endoplasmic reticulum.

Adenoma↗