Biomedical subjects

N Shikata

Publications and source records attributed to N Shikata.

At least 37 records · Page 2Linked to original sources

PubMed1999

Biphasic effect of colchicine on acute liver injury induced by carbon tetrachloride or by dimethylnitrosamine in mice.

BACKGROUND/AIMS: The effects of colchicine on acute liver injury induced by carbon tetrachloride or by dimethylnitrosamine in mice were examined. METHODS: Nonlethal acute liver injury was induced in male BALB/c mice by a single intraperitoneal injection of 0.8 ml/kg carbon tetrachloride or 15 mg/kg dimethylnitrosamine. 0.6 mg/kg colchicine was administered 18 h or 2 h intraperitoneally before hepatotoxin treatment. RESULTS: Reversible centrilobular to mid-zone necrosis and apoptosis occupying half the liver lobular area was evoked by carbon tetrachloride, and dimethylnitrosamine, respectively. Administration of colchicine 18 h before hepatotoxins markedly suppressed liver injury, whereas colchicine administration 2 h before the hepatotoxins accelerated it. The hepatoprotective effect evoked by colchicine was due to reduction in liver cytochrome P450 content and P450 2E1 activity. In contrast, the hepatodestructive effect seen in the carbon tetrachloride model was related to the extent of lipid peroxidation promoting plasma membrane destruction, while the hepatodestructive effect in the dimethylnitrosamine model was due to suppression of Bcl-X(L) expression, leading to acceleration of apoptosis. CONCLUSIONS: A biphasic effect of colchicine on carbon tetrachloride- and dimethylnitrosamine-induced acute liver injury was seen. The time interval between colchicine administration and the hepatotoxin treatment is crucial to the subsequent development of liver lesions.

Alanine Transaminase↗

PubMed1999

Masseter muscle activity during the whole day in children and young adults.

Changes in size and shape of the craniofacial skeleton during growth may be related to the masticatory muscle function in daily life. The purpose of this study was to measure the masseter muscle activity during the whole day in children and to investigate the differences between children and young adults. Fifteen children (7.8-13.0 years of age) and 30 young adults (20.3-34.7 years of age), who had acceptable occlusions without any remarkable skeletal discrepancy or temporomandibular disorder, were used as the subjects. In both children and young adults, most high-amplitude bursts of masseter muscle appeared mainly during mealtime, whereas a substantially larger number of low-amplitude ones were widely distributed throughout the whole day. The number and total duration of bursts of masseter muscle activity during the whole day was greater in children than in young adults, although significant differences were not found between the sexes. During daytime and sleep, both the number and total duration of bursts were greater in children. During mealtime, no significant differences in the number of bursts were found between children and young adults, however, the duration of bursts tended to be longer in children. It is concluded that the masseter muscle activity during the whole day is greater in children than in young adults.

Adolescent↗

PubMed1999

Sjögren's syndrome in mice carrying the Ipr(cg) gene and the therapeutic efficacy of an immunosuppressive agent FK506.

The influence of the Ipr(cg) gene on the development of Sjögren's syndrome was followed up to 5 months of age in male and female mice of MRL, CBA and C3H strains. In MRL-Ipr(cg) mice, focal mononuclear cell infiltration started at 2 months and became conspicuous after 3 months of age in the lacrimal and submandibular glands but was minimal in the parotid and sublingual glands, even at 5 months of age, without any apparent sex effects found. In CBA and C3H mice carrying the Ipr(cg) gene, this manifestation of Sjögren's syndrome was much less prominent, indicating that the participation of some genes of the MRL strain may be indispensable for the development of Sjögren's syndrome in mice carrying this gene. In MRL-Ipr(cg) mice, an immunosuppressive agent, FK506, improved the serological abnormalities (decreased levels of anti-double-stranded DNA antibody of IgG2a and IgG3 subclasses) and proteinuria. It also reduced the manifestations of Sjögren's syndrome when it was intraperitoneally administered three times weekly at a dose of 2 mg/kg from 6 weeks (before disease onset) until 5 months of age (the termination of the experiment). Although VP8.2+ T cells have been demonstrated to be responsible for causing several autoimmune diseases, the selective deletion of Vp8.2+ T cells with the superantigen encoded by mouse mammary tumor virus did not affect the disease severity at all, suggesting that this T cell repertoire may not play a crucial role in induction of Sjögren's syndrome.

Animals↗

PubMed1999

Mechanisms of photoreceptor cell apoptosis induced by N-methyl-N-nitrosourea in Sprague-Dawley rats.

A single intraperitoneal injection of 75 mg/kg N-methyl-N-nitrosourea (MNU) was given to 50-day-old female Sprague-Dawley rats and examined sequentially 12 and 24 hours, and 3 and 7 days after MNU treatment. Photoreceptor cell death was evoked in all treated rats. After MNU treatment, 7-methyldeoxyguanosine DNA adduct was detected selectively in photoreceptor cell nuclei at 12 hours, followed by photoreceptor cell apoptosis as confirmed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling signals which peaked at 24 hours and continued until day 7 when several layers of photoreceptor cell nuclei were left. In apoptosis cascade, down-regulation of Bcl-2 was seen at 12 hours and up-regulation of Bax was seen at 24 hours, and caspase family (caspase 3/CPP32, caspase 6/Mch2, and caspase 8/FLICE protease) activities peaked 72 hours after MNU treatment. Therefore MNU-induced photoreceptor cell death was attributed to DNA adduct formation restricted to photoreceptor cell nuclei leading to photoreceptor cell apoptosis by up-regulation of Bax protein, down-modulation of Bcl-2 protein, and activation of caspases 3, 6, and 8.

Animals↗

PubMed1998

Retinal degeneration induced by N-methyl-N-nitrosourea in Syrian golden hamsters.

BACKGROUND: The sequential retinal changes in Syrian golden hamsters induced by N-methyl-N-nitrosourea (MNU) have not been studied. METHODS: Female hamsters received a single intraperitoneal injection of 90 mg/kg MNU at 50 days of age, and the retina was examined light and electron microscopically, immunohistochemically and by the TdT-mediated dUTP-digoxigenin nick end labeling (TUNEL) method until 20 weeks after the treatment. RESULTS: The retinal changes were as follows: (1) Photoreceptor apoptosis occurred 1 day after the treatment and resulted in photoreceptor loss at day 7. During the degeneration, Müller cell proliferation was conspicuous at day 5. (2) After the photoreceptor cell loss, migration of the pigment epithelial cells in all layers of the retina which were in contact with blood vessels occurred. Due to the Müller cell proliferation, gliosis was prominent at the later stage. CONCLUSIONS: The MNU injection caused photoreceptor apoptosis followed by pigment epithelial cell migration around the blood vessels, accompanied by gliosis. The primary event and the course of this disease closely resemble those of retinitis pigmentosa in humans.

Animals↗

PubMed1998

Bax and Bcl-2 expressions predict response to radiotherapy in human cervical cancer.

PURPOSE: The ratio of Bcl-2 to Bax expression determines survival or death following an apoptotic stimulus. In order to establish a new predictor of the outcome of treatment for human cervical carcinoma, we investigated the relationship between the expressions of the Bax and Bcl-2 proteins and the response to radiotherapy after the administration of 10.8 Gy. METHODS: A total of 44 patients with histologically proven carcinoma of the uterine cervix, including three with recurrent cervical stump carcinomas, were treated with definitive radiotherapy. The presence of mutations in exons 5-8 of the p53 gene was analyzed by a single-strand conformation polymorphism analysis and DNA sequencing. RESULTS: Forty patients were found to have wild-type p53, and the remaining four had mutant p53. The Bax and Bcl-2 protein expressions prior to radiotherapy did not correlate with response and survival. However, the Bax and Bcl-2 protein expressions after radiotherapy correlated with both response and survival. Bax-positive tumors showed significantly better responses than the Bax-negative tumors after 10.8 Gy radiation (P = 0.0002). In contrast, the Bcl-2-positive tumors showed significantly poorer responses than the Bcl-2-negative tumors after radiation (P = 0.002). Increased Bax expression after the 10.8 Gy radiotherapy was found to be correlated with good survival (P = 0.04). In contrast, increased Bcl-2 expression after such radiotherapy was correlated with poor survival (P = 0.002). CONCLUSION: The levels of Bax and Bcl-2 expression after 10.8 Gy radiotherapy are useful prognostic markers in patients with human cervical carcinoma.

Adult↗

PubMed1998

Juvenile hyaline fibromatosis: a report of two unrelated adult sibling cases and a literature review.

Two unrelated adult sibling cases (36- and 32-year-old females) of juvenile hyaline fibromatosis are presented. The parents of one of these patients were non-consanguineous but natives of a small island, and one elder sister among four siblings was affected with the same disease. The parents of the other patient were consanguineous, and one other sibling suffered from the identical disease. Both patients presented with multiple subcutaneous nodules, which they had had since infancy, and had undergone numerous surgical excisions. Light microscopy examination of skin lesions from both patients showed identical histology; an abundance of a homogenous, amorphous, eosinophilic extracellular matrix in which spindle-shaped cells were embedded. Electron microscopically, the spindle-shaped cells had hypertrophic Golgi apparatus and dilated, rough endoplasmic reticulum. Fine fibrillar and granular material-filled structures, the contents of which were occasionally released into the extracellular matrix, were also seen. Immunohistochemically, the spindle-shaped cells were vimentin-positive but negative for alpha-smooth muscle actin and S-100 protein, and the hyaline ground substance was positive for type I and type III collagen but negative for type II and type IV collagen and tenascin. Matrix metalloproteinase-1, -2, and -9, and tissue inhibitor of matrix metalloproteinase (TIMP)-2 was positive but TIMP-1 was negative. A review of 39 cases of juvenile hyaline fibromatosis in the literature is also presented. In summary, skin lesions may be the most outstanding symptoms of juvenile hyaline fibromatosis, but joint contracture and gingival hypertrophy precede the skin manifestation.

Adult↗

PubMed1998

Papillary eccrine adenoma: immunohistochemical study and literature review.

A case of papillary eccrine adenoma on the right forearm of a 78-year-old Japanese woman is reported. The tumor was 1.3 cm in diameter, occupying the whole thickness of the dermis. Histologically, the tumor was composed of dilated tubules of various sizes with intraluminal papillary projections, and was surrounded by a fibrous stroma. An immunohistochemical study revealed that the proliferating tubules were composed of a single outermost layer of alpha-smooth muscle actin- and keratin 14-positive myoepithelial cells, and keratin 8-positive inner cells. This antigen expression pattern was comparable to that of the normal eccrine secretory coil, which indicates that the tumor differentiated toward the secretory coil of an eccrine sweat gland.

Actins↗

PubMed1998

Primary pulmonary artery sarcoma.

A 66-year-old woman with a history of mitral valve replacement with a Starr-Edwards ball valve 25 years ago was treated for refractory heart failure but died of right heart failure. At autopsy, primary pulmonary artery sarcoma was found in the right ventricular outflow tract, main pulmonary trunk, and bilateral pulmonary artery, and had invaded the aortic arch. The pathohistologic diagnosis was osteosarcoma. Echocardiography, chest computed tomography and right ventriculography performed 1 year before death did not reveal the presence of a tumor in the pulmonary artery. The history of this patient shows that primary pulmonary artery sarcoma grows rapidly, with, in this case, the patient dying within 1 year of its appearance.

Aged↗

PubMed1998

[Bax and Bcl-2 expression predict response to radiotherapy in human cervical cancer].

To establish a new predictor of the outcome of treatment for human cervical carcinoma, we investigated the relationship between the expression of the Bax and Bcl-2 proteins and the response to radiotherapy after administration of 10.8 Gy. A total of 44 patients with uterine cervical carcinoma were treated with definitive radiotherapy. On univariate analysis, Bax and Bcl-2 protein expression prior to radiotherapy did not correlate with survival. Increased Bax expression after 10.8 Gy correlated with good survival (p = 0.003). In contrast, increased Bcl-2 expression after 10.8 Gy correlated with poor survival (p < 0.0001). On multivariate analysis, Bcl-2 expression after 10.8 Gy of radiation was the most important predictor of treatment outcome. The levels of Bax and Bcl-2 expression after 10.8 Gy of radiotherapy are useful prognostic markers in patients with human cervical carcinoma.

Adenocarcinoma↗

PubMed1997

Studies on the mechanism of dimethylnitrosamine-induced acute liver injury in mice.

Male and female adult C3H- +/+, C3H-gld/gld.lpr/lpr (gld.lpr) and CBA-lprcg/lprcg (lprcg) mice were given a single i.p. dose of 30 mg/kg dimethylnitrosamine (DMN). Liver tissues were collected from mice killed 6, 12, 24 and 36 hrs post treatment, and the progression of the lesions was characterized morphologically and by the TUNEL method. DMN induced centrilobular hepatic injury accompanied with acute hemorrhage, and all mice died 36 to 48 hrs after the dosing. At 12 hrs after DMN administration, centrilobular hepatocytes revealed nuclear chromatin clumping. At 24 hrs, hepatocyte nuclei became fragmented to form apoptotic cells. Ultrastructurally, chromatin was condensed into a compact granular mass or crescent granular cap at the nuclear periphery. At 36 hrs, the number of apoptotic cells increased and they protruded into the sinusoid or were engulfed by the neighboring hepatocytes. A TUNEL-positive signal preceded the morphological changes and a few normal appearing centrilobular hepatocytes were positive 6 hrs post dosing. Endothelial damage was seen immunohistochemically at 24 hrs by disruption of type IV collagen and factor VIII-related antigen, resulting in massive hemorrhage in the centrilobular to mid zone. No inflammatory reactions were observed throughout the degeneration. The findings indicate that a single i.p. administration of DMN induced severe and fatal toxicity in liver tissues in mice which resembled human fulminant hepatitis. However, as gld-lpr and lprcg mice defective in apoptosis through the Fas system also showed similar severe liver damage, the Fas/Fas ligand system is not involved in DMN-induced liver apoptosis. No other organs or tissues were damaged, and the control mouse liver was intact.

Acute Disease↗

PubMed1997

Inhibition of tumor growth and metastasis by angiogenesis inhibitor TNP-470 on breast cancer cell lines in vitro and in vivo.

Antitumor and antimetastatic activity of the angiogenesis inhibitor O-(chloroacetyl-carbamoyl) fumagillol (TNP-470), a semisynthetic analogue of fumagillin, was evaluated in breast cancer cell lines. In an in vitro MTT assay, after 72 hrs continuous exposure to TNP-470, growth inhibition was observed in all seven cell lines of murine (JYG-A, JYG-B, DD-762, and BALB/c-MC) or human (KPL-1, MDA-MB-231, and MKL-F) origin, in which the 50% inhibitory concentrations (IC50) at 72 hrs treatment were 4.6, 4.4, 4.6, 10.1, 35.0, 25.3, and 33.4 micrograms/ml, respectively. In an in vivo assay using JYG-A, JYG-B, KPL-1, and MDA-MB-231 cells by orthotopic (right thoracic mammary fat pad) transplantation in female nude mice, TNP-470 at 30 or 50 mg/kg body weight was injected s.c. every other day from the day of tumor cell inoculation until the end of the experiment. The inhibitory effect on primary tumor growth was obtained in all four cell lines in a dose-dependent manner. In the 50 mg/kg TNP-470-treated group, the reductions in tumor weight of the JYG-A, JYG-B, KPL-1, and MDA-MB-231 cells with respect to the controls were 50%, 30%, 4%, and 49%, respectively. Metastasis was seen in the JYG-A, JYG-B, and KPL-1 cells. The numbers of mice bearing pulmonary metastases of JYG-A and JYG-B cells and regional axillary lymph node metastases of KPL-1 cells were reduced, and TNP-470 at the 50 mg/kg dose to KPL-1 cells significantly reduced lymph node metastases compared with the control. Although the weight gain was retarded in the TNP-470-treated mice, weight loss was not seen. TNP-470 was highly effective in the treatment of breast cancer cells. These results suggest that the clinical use of TNP-470 may be a promising treatment for breast cancer patients.

Animals↗

PubMed1997

Morphologic characteristics of N-methyl-N-nitrosourea-induced retinal degeneration in C57BL mice.

Morphologic characteristics of retinal degeneration induced by a single systemic administration of N-methyl-N-nitrosourea (MNU) in mice was investigated. The aim was to characterize the MNU-induced retinal lesions in mice and compare them with human retinitis pigmentosa. A dose of 60 mg/kg body weight MNU, injected intraperitoneally into male and female C57BL mice, evoked progressive retinal degeneration in all treated mice, while control mice remained normal. An early change was photoreceptor apoptosis followed by infiltration of macrophages and swelling of the pigment epithelial cells with phagosomal inclusions for apoptotic photoreceptor cell removal. Loss of the majority of photoreceptor cells occurred within a week. Then, Feulgen-positive corpuscles, indicative of an aggregation of degenerative photoreceptor elements, vitread the outer limiting membrane were surrounded by Müller cell processes, and the duplication of the pigment epithelial cells sclerad the outer limiting membrane were seen 2 and 3 weeks after the treatment. Finally, the Feulgen-positive corpuscles disappeared and Müller cell processes were in direct contact with the continuous lining of the single layer of pigment epithelial cells. As in retinitis pigmentosa in humans, the primary event was loss of photoreceptor cells by apoptosis, but the migration of the pigment epithelial cells within the retina was not seen in the present model.

Animals↗

PubMed1997

[A case of invasive thymoma that recurred with pericardial effusion 15 years postoperatively].

We treated a 74-years-old male who had recurrence with pericardial effusion and a tumor between the pulmonary artery and left atrium 15 years after operation for invasive thymoma complicated by myasthenia gravis. Despite pericardial drainage, CDDP infusion, and radiation therapy for the tumor, the patient died due to pneumonia after 1 and half years. Long-term observation is considered to be needed after surgical resection of thymoma for recurrence or multiple oncogenesis in ectopic thymus.

Aged↗

PubMed1996

Colon carcinogenesis in shrews by intrarectal infusion of N-methyl-N-nitrosourea.

Intrarectal infusion of a 0.15 ml solution containing 1.5 mg or 0.5 mg of N-methyl-N-nitrosourea (MNU) was given to female shrews from 6 weeks of age. Fifteen shrews were given 16 doses of 1.5 mg MNU administered biweekly (group 1), 15 shrews were given 24 doses of 0.5 mg MNU weekly (group 2), and four untreated shrews served as controls (group 3). Moribund shrews were killed during the course of the experiment and all remaining animals were killed at 37 weeks of age and terminated the experiment. The mean age when killed was 30.8 weeks in group 1 and 36.2 weeks in group 2. All autopsied shrews in group 1 and group 2, 13 shrews each, had colon cancers, and there were a few small intestinal cancers and uterine squamous cell carcinomas, while no tumors were seen in the untreated shrews. The colonic lesions were of both exophytic and endophytic type with a variety of histologies and depths of invasion. Mesenteric lymph node metastasis was seen in 31% (4/13) of group 1 and 23% (3/13) of group 2. Thus, MNU, a colonotrophic carcinogen in rodents, also induced colon cancer in shrews in the present study.

Administration, Rectal↗

PubMed1996

Inhibitory Effect of the Angiogenesis Inhibitor O-(Chloroacetyl-carbamoyl)fumagillol(TNP-470) on Tumor Growth and Metastasis of Murine Mammary Tumor Cell Line (JYG-B)Inoculated in Female Nude Mice.

The effect of the potent angiogenesis inhibitor O-(chloroacetyl-carbamoyl) fumagillol(TNP-470), a semisynthetic analogue of fumagillin on tumor growth and metastasis was studied using murine mammary tumor cells (JYG-B) inoculated into female nude mice. Injection of TNP-470 at 10 and 30 mg/kg doses, 3 times a week, until the end of the experiment (41 days)inhibited the s.c.inoculated primary tumor growth in a dose-dependent manner (45%and 65% in volume, respectively). TNP-470 at 30 and 60 mg/kg doses, 3 times a week, until the end of the experiment (35 days), reduced the weight of the i.p. inoculated total tumor mass of abdominal dissemination in a dose-dependent manner (54% and 76%, respectively). Pulmonary metastasis was found in all mice but TNP-470 significantly reduced the lung weight reflecting the total volume of the metastatic foci, and the numbers of metastatic foci in the liver and kidneys was reduced by TNP-470 treatment. These findings show that the angiogenesis inhibitor (TNP-470)has a strong inhibitory effect on tumor grwoth and metastasis in vivo.

Journal Article↗

PubMed1996

Angiosarcoma of the Breast: Immunohistochemical Demonstration of Steroid Receptors and Literature Review.

A 44-year-old female with bilateral angiosarcoma of the breast with multiple skin metastases is reported. She presented with a 6x8 cm and 1x1 cm mass in her left and right breasts, respectively, and multiple skin lesions around the chest. Histologically, the excised tumor was diagnosed as angiosarcoma of the breast with skin metastasis. Tumor cells were immunohistochemically positive with factor VIII-related antigen, CD34, alpha-smooth muscle actin and vimentin, and positive with UEA-I lectin. The majority of tumor cell nuclei expressed progesterone receptor (PgR) protein but estrogen receptro (ER) protein and androgen receptor (AR) protein were nagative. According to the literature, angiosarcoma of the breast mostly affects females in their fourth (33%) and fifth (40%) decades (mean age, 39.5 +/- 10.7 years). The survival rate depends on tumor size and tumor differentiation. The 3-year survival rate is 86% in patients with a tumor size less than 5 cm, and 90% in well-differentiated group I lesions.

Journal Article↗

PubMed1996

Effect of ethanol on esophageal cell proliferation and the development of N-methyl-N'-nitro-N-nitrosoguanidine induced-esophageal carcinoma in shrews.

The effect of ethanol (EtOH) on esophageal cell proliferation and the development of esophageal cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in shrews were investigated. Sequential histological examination was done, and cell proliferation was assessed by BrdU labeling. At 5 weeks of age, animals were given tap water, 2% EtOH, 50 ppm MNNG, or 50 ppm MNNG plus 2%, 5% or 10% EtOH in the drinking water. Administration of 10% and 5% EtOH simultaneously with MNNG caused death in 40% (10/25) within 4 days and in 20% (6/30) within 7 days respectively, whereas other treatment were well tolerated with no sudden deaths. Administration of 2% EtOH for 30 weeks caused a 2-fold increase, and that of MNNG caused a 4.5-fold increase in the proliferation index of the basal cells of the esophagus compared with control shrews, and MNNG plus 2% EtOH caused a 5.5-fold increase. In MNNG-treated shrews, with or without 2% EtOH administration, sequential histological examination of esophageal tissue revealed a similar change; dysplasia appeared at 30 weeks of age, squamous cell carcinoma occurred at 35 weeks of age, and the depth of invasion extended to adventitia at 45 weeks of age. These finding indicate that treatment with 2% EtOH promoted the proliferation of esophageal basal cells but did not alter the tumor induction period and did not have tumor-promoting activity. EtOH per se was not carcinogenic; no tumors were seen in shrews not administered MNNG.

Animals↗