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Biomedical subjects

M Fujimura

Publications and source records attributed to M Fujimura.

At least 55 records · Page 3Linked to original sources
PubMed2001

Absence of estrogen receptor-alpha expression in human ovarian clear cell adenocarcinoma compared with ovarian serous, endometrioid, and mucinous adenocarcinoma.

The mechanism that regulates growth in ovarian clear cell adenocarcinoma (CCA) is not well understood. A high incidence of concurrent endometriosis with CCA may indicate that estrogen is a growth promotor in CCA. To determine estrogen as a growth promotor, the authors investigated the presence or absence of estrogen receptor-alpha (ER-alpha), ER-beta, progesterone receptor, and dioxin receptor (i.e., aromatic hydrocarbon receptor) in clinically resected ovarian CCA, serous adenocarcinoma (SAC), endometrioid adenocarcinoma (EAC), and mucinous adenocarcinoma (MAC) specimens using an immunohistochemical method. Expression of ER-alpha and ER-beta messenger ribonucleic acid was examined by reverse transcription-polymerase chain reaction in three established CCA cell lines: KK, RMG-1, and HAC-II. None of the surgically resected CCA and CCA cell lines showed positive staining for ER-alpha. Conversely, 97.2% of SACs, 100% of EACs, and 70% of MACs showed positive nuclear staining for ER-alpha (p < 0.001). Conversely, positive ER-beta staining for CCA (39.3%) was similar to that of SAC (41.7%) and MAC (30.0%). EAC (75%) showed a higher expression of ER-beta (p < 0.02). Progesterone receptor was detected in only 10.7% of CCA, compared with SAC and EAC (SAC, 86.1%; EAC, 91.7%; p < 0.01). Aromatic hydrocarbon receptor was detected in all histologic types at an incidence of approximately 50% to 60%. Messenger ribonucleic acid of ER-alpha and ER-beta was not detected in the three CCA cell lines. These findings indicate biologic characteristics that distinguish CCA from other types of ovarian epithelial cancer.

Adenocarcinoma, Clear Cell↗
PubMed2001

SOD1 down-regulates NF-kappaB and c-Myc expression in mice after transient focal cerebral ischemia.

Reactive oxygen species (ROS) are implicated in reperfusion injury after focal cerebral ischemia (FCI). Reactive oxygen species regulate activity of transcription factors like NF-kappaB. The authors investigated the role of ROS in NF-kappaB activity after FCI using transgenic mice that overexpressed human copper/zinc-superoxide dismutase (SOD1) and that had reduced infarction volume after FCI. Superoxide dismutase transgenic and wild-type mice were subjected to 1 hour of middle cerebral artery occlusion (MCAO) and subsequent reperfusion. Immunohistochemistry showed SOD1 overexpression attenuated ischemia-induced NF-kappaB p65 immunoreactivity. Colocalization of NF-kappaB and the neuronal marker, microtubule-associated proteins (MAPs), showed that NF-kappaB was up-regulated in neurons after FCI. Electrophoretic mobility shift assays showed that SODI overexpression reduced ischemia-induced NF-kappaB DNA binding activity. Supershift assays showed that DNA-protein complexes contained p65 and p50 subunits. Immunoreactivity of c-myc, an NF-kappaB downstream gene, was increased in the ischemic cortex and colocalized with NF-kappaB. Western blotting showed that SOD1 overexpression reduced NF-kappaB and c-Myc protein levels in the ischemic brain. Colocalization of c-Myc and TUNEL staining was observed 24 hours after FCI. The current findings provide the first evidence that SOD1 overexpression attenuates activation of NF-kappaB after transient FCI in mice and that preventing this early activation may block expression of downstream deleterious genes like c-myc, thereby reducing ischemic damage.

Animals↗
PubMed2001

Manganese Superoxide Dismutase Affects Cytochrome c Release and Caspase-9 Activation After Transient Focal Cerebral Ischemia in Mice.

Release of cytochrome c from mitochondria to cytosol is a critical step in the mitochondrial-dependent signaling pathways of apoptosis. The authors have reported that manganese superoxide dismutase (Mn-SOD) attenuated cytochrome c release and apoptotic cell death after focal cerebral ischemia (FCI). To investigate downstream to the cytochrome c-dependent pathway, the authors examined caspase-9 activation after transient FCI by immunohistochemistry and Western blotting in both wild-type and Sod2 -/+ mice. Mice were subjected to 60 minutes of middle cerebral artery occlusion followed by 1, 2, 4, or 24 hours of reperfusion. Two hours after reperfusion, cytochrome c and caspase-9 were observed in the cytosol and significantly increased in Sod2 -/+ mutants compared with wild-type mice as shown by Western blotting. Immunofluorescent double labeling for cytochrome c and caspase-9 showed cytosolic cytochrome c 1 hour after transient FCI. Cleaved caspase-9 first appeared in the cytosol at 2 hours and colocalized with cytochrome c. Terminal deoxynucleotidyl transferase-mediated uridine 5;-triphosphate-biotin nick and labeling (TUNEL) showed significant increase of positive cells in Sod2 -/+ mice compared with the wild-type in the cortex, but not in the caudate putamen. The current study revealed Mn-SOD might affect cytochrome c translocation and downstream caspase activation in the mitochondrial-dependent cell death pathway after transient FCI.

Animals↗
PubMed2001

Oxidative stress-dependent release of mitochondrial cytochrome c after traumatic brain injury.

Mitochondrial cytochrome c translocation to the cytosol initiates the mitochondrial-dependent apoptotic pathway. This event has not been previously reported in traumatic brain injury (TBI). The authors determined the expression of cytochrome c in cytosolic and mitochondrial fractions after severe TBI produced by the controlled cortical impact model in the mouse. One hour after trauma there was an increase in cytosolic cytochrome c immunoreactivity. The increases in cytosolic cytochrome c preceded DNA fragmentation, which started at 4 hours. Western blots of mitochondrial and cytosolic fractions confirmed that there was a translocation of cytochrome c from the mitochondria after TBI. Mice deficient in manganese superoxide dismutase (MnSOD) showed an increased loss of mitochondrial cytochrome c after trauma, but less apoptotic cell death 4 and 24 hours after injury compared with wild-type control mice. However, the overall cell death was increased in MnSOD mice, as illustrated by a larger cortical lesion in these animals. The results show that cytochrome c is released from the mitochondria after severe TBI partly by a free radical-dependent mechanism, and that massive mitochondrial cytochrome c release is a predictor of necrotic cell death rather than apoptosis.

Animals↗
PubMed2001

Matrix metalloproteinase inhibition prevents oxidative stress-associated blood-brain barrier disruption after transient focal cerebral ischemia.

Oxidative stress generated during stroke is a critical event leading to blood-brain barrier (BBB) disruption with secondary vasogenic edema and hemorrhagic transformation of infarcted brain tissue, restricting the benefit of thrombolytic reperfusion. In this study, the authors demonstrate that ischemia-reperfusion-induced BBB disruption in mice deficient in copper/zinc-superoxide dismutase (SOD1) was reduced by 88% ( P < 0.0001) and 73% ( P < 0.01), respectively, after 3 and 7 hours of reperfusion occurring after 1 hour of ischemia by the inhibition of matrix metalloproteinases. Accordingly, the authors show that local metalloproteinase-generated proteolytic imbalance is more intense in ischemic regions of SOD1 mice than in wild-type litter mates. Moreover, active in situ proteolysis is, for the first time, demonstrated in ischemic leaking capillaries that produce reactive oxygen species. By showing that oxidative stress mediates BBB disruption through metalloproteinase activation in experimental ischemic stroke, this study provides a new target for future therapeutic strategies to prevent BBB disruption and potentially reperfusion-triggered intracerebral hemorrhage.

Animals↗
PubMed2001

Macrophage colony-stimulating factor prevents febrile neutropenia induced by chemotherapy.

There are very few studies describing the preventive effect of macrophage colony-stimulating factor (M-CSF/CSF-1) on chemotherapy-induced infection. In this study, we evaluated the changes in superoxide anion production by granulocytes before and after chemotherapy in ovarian cancer patients and investigated the preventive effect of M-CSF on chemotherapy-induced febrile neutropenia. Three courses of chemotherapy [paclitaxel 180 mg/m(2) and carboplatin (area under the curve; AUC 5)] were administered to 32 ovarian cancer patients, and seven patients presented febrile neutropenia. In the 25 afebrile patients, the percentage of superoxide anion production by granulocytes was significantly decreased from 86.5 +/- 7.7 (%) to 75.1 +/- 8.8 (%) at day 7 and 71.0 +/- 6.3 (%) at day 14 without administration of CSF. However, in the patients who presented febrile neutropenia, it was more severely decreased from 86.8 +/- 6.8 (%) to 60.0 +/- 9.9 (%) at day 7 and 56.8 +/- 5.0 (%) at day 14 without administration of CSF. When M-CSF was administered to all patients in the next course with the same dose of chemotherapy, the incidence of febrile neutropenia was significantly decreased (P = 0.0195), and the duration of fever (>or= 38.0 degrees C) and high serum C-reactive protein (CRP) (>or= 2.0 mg/dl) were also significantly shortened (P = 0.0023, P = 0.0051). Moreover, in these M-CSF-treated patients, the percentage of superoxide anion production by granulocytes was maintained at the level before chemotherapy. These findings indicate that severe impairment of granulocyte function leads to febrile neutropenia, and that M-CSF reduces the incidence of febrile neutropenia by maintaining or improving granulocyte function.

Adolescent↗
PubMed2001

Effects of central and peripheral urocortin on fed and fasted gastroduodenal motor activity in conscious rats.

Since few previous studies have examined the effects of urocortin on physiological fed and fasted gastrointestinal motility, we administered urocortin intracerebroventricularly (icv) or intravenously (iv) in freely moving conscious rats and examined the changes in antral and duodenal motility. Icv and iv injection of urocortin disrupted fasted motor patterns of gastroduodenal motility, which were replaced by fed-like motor patterns. When urocortin was given icv and iv in the fed state, the motor activity remained like the fed patterns but % motor index (%MI) was decreased in the antrum and increased in the duodenum. Increase in the %MI in the duodenum induced by urocortin was shown as a nonpropagated event, since the transit of nonnutrient contents in the duodenum was decreased by icv and iv injection of urocortin. Changes in the gastroduodenal motility induced by icv injection of urocortin were abolished in animals with truncal vagotomy but not altered in animals with mechanical sympathectomy, suggesting that the vagal pathway may mediate the central action of urocortin. Neither urocortin antiserum nor alpha-helical CRF-(9-41) affected fed and fasted gastroduodenal motility, suggesting that endogenous urocortin is not involved in regulation of basal gastroduodenal motility.

Animals↗
PubMed2001

Mechanisms in regulating the release of serotonin from the perfused rat stomach.

The mechanisms regulating the release of serotonin into the portal circulation as well as into the gastric lumen were studied in the isolated vascularly and luminally perfused rat stomach. Immunohistochemical study of the rat stomach showed that serotonin-containing enterochromaffin (EC) cells were densely packed in the antral mucosa, sparsely scattered in the corpus, and not found in the fundus. Such morphological findings suggest that serotonin detected in this study may have originated from antral EC cells. Luminal acidification stimulated the vascular release of serotonin but did not affect the luminal release of serotonin. The basal release of serotonin into the vasculature was 10 times higher than that into the gastric lumen at intragastric pH 2. The vascular release of serotonin is regulated by stimulation from cholinergic nicotinic mechanisms, whereas inhibitory neurotransmitters such as vasoactive intestinal peptide and NO are probably not involved. Somatostatin and peptide YY originating from endocrine cells may exert direct inhibitory effects, possibly via somatostatin and peptide YY receptors on the EC cells, and a cholinergic muscarinic mechanism may exert indirect effects on the vascular release of serotonin via the muscarinic receptor on the endocrine cells.

Acids↗
PubMed2001

Changes in serotonin levels and 5-HT receptor activity in duodenum of streptozotocin-diabetic rats.

Few previous studies have discussed the changes in serotonin receptor activity in the small intestine of diabetic animals. Therefore, we examined serotonin content in duodenal tissue and dose-dependent effects of serotonin agonists and antagonists on the motor activity of ex vivo vascularly perfused duodenum of streptozotocin (STZ)-diabetic rats. Serotonin content was significantly increased in enterochromaffin cells but not altered in serotonin-containing neurons in STZ-diabetic rats. Motor activity assessed by frequency, amplitude, and percent motility index per 10 min of pressure waves was reduced in the duodenum of diabetic rats, and this reduction was reversed by insulin treatment. Serotonin dose dependently increased the motor activity in control rat duodenum but only a higher concentration of serotonin increased the motor activity in diabetic rats. The 5-hydroxytryptamine (5-HT) receptor subtype 4 (5-HT(4)) antagonist SB-204070 dose dependently reduced motor activity in both control and diabetic rats, whereas the 5-HT(3) receptor antagonist azasetron, even at a higher concentration, failed to affect motor activity in diabetic rat duodenum but dose dependently reduced motor activity in control rat duodenum. These results suggest that 5-HT(3) receptor activity was impaired but 5-HT(4) receptor activity was intact in STZ-diabetic rat duodenum. Such an impairment of 5-HT(3) receptor activity may induce the motility disturbance in the small intestine of diabetes mellitus.

Animals↗
PubMed2001

Increased cytochrome c-mediated DNA fragmentation and cell death in manganese-superoxide dismutase-deficient mice after exposure to subarachnoid hemolysate.

BACKGROUND AND PURPOSE: We sought to investigate the mechanisms for oxidative injury caused by subarachnoid hemolysate, a pro-oxidant. METHODS: Injection of 50 microL of subarachnoid hemolysate or saline was performed in CD1 mice (n=75), mutant mice deficient in Mn-superoxide dismutase (Sod2+/-; n=23), and their wild-type littermates (n=23). Subcellular location of cytochrome c was studied by immunocytochemistry, immunofluorescence, and immunoblotting of cellular fractions. DNA fragmentation was assessed though DNA laddering and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL). Cell death was examined through basic histology. RESULTS: Cytochrome c immunoreactivity was present in the cytosol of neurons at 2 hours after hemolysate injection and increased by 4 hours compared with saline-injected animals (P:<0.02). Cytosolic cytochrome c was more abundant in Sod2+/- mutants. DNA fragmentation was evident at 24 hours, but not 4 hours, after hemolysate injection as determined by DNA laddering and TUNEL staining (P:<0.02). DNA fragmentation colocalized to cells with cytosolic cytochrome c and iron. In Sod2+/- mutants, the extent of fragmentation was increased as determined by TUNEL staining (52% increase; P:<0.02) and DNA laddering (optical density=0.819 versus 0.391; P:<0.01). Cell death was evident on basic histology as early as 4 hours after hemolysate injection. No cell death was evident in controls. In Sod2+/- mutants, cell death was increased by 51% compared with wild-type littermates (P:<0.05). CONCLUSIONS: These results demonstrate that subarachnoid blood products are associated with the presence of cytochrome c in the cytosol and subsequent cell death in neurons. It appears that Mn-superoxide dismutase plays a role in preventing cell death after exposure to subarachnoid blood products.

Animals↗
PubMed2001

Overexpression of copper-zinc superoxide dismutase attenuates acute activation of activator protein-1 after transient focal cerebral ischemia in mice.

BACKGROUND AND PURPOSE: Reactive oxygen species (ROS) have been implicated in reperfusion injury after focal cerebral ischemia (FCI). ROS are known to regulate the activity of transcription factors such as activator protein-1 (AP-1), which is a dimer consisting of members of the Jun and Fos families. We investigated the role of ROS in AP-1 activity after FCI using transgenic mice that overexpressed copper-zinc superoxide dismutase (SOD1) and that had reduced infarction volume after FCI. METHODS: The SOD1 transgenic mice and their wild-type littermates were subjected to middle cerebral artery occlusion and reperfusion by intraluminal suture blockade. After 60 minutes of middle cerebral artery occlusion, mice were allowed to recover for 1, 2, and 4 hours before euthanasia. Protein expression of c-Jun and c-Fos was examined by immunohistochemistry and Western blotting. AP-1 DNA-protein binding activity was assessed by electrophoretic mobility shift assays. RESULTS: In wild-type mice, immunohistochemistry demonstrated acute c-Jun and c-Fos activation in ischemic cortex and its outer boundary. Expression of both was reduced in SOD1 transgenic mice. Western blotting confirmed that SOD1 overexpression was associated with reduced c-Jun and c-Fos protein levels in ischemic brain. Electrophoretic mobility shift assays revealed that the ischemia-enhanced DNA binding activity observed in wild-type mice was reduced in SOD1 transgenic mice. Supershift assays indicated that c-Jun participated in the bound AP-1 complex. CONCLUSIONS: SOD1 overexpression prevents early activation of AP-1 after transient FCI in mice. This may block the expression of downstream target genes that are injurious, thereby reducing the infarction volume after transient FCI in mice.

Animals↗
PubMed2001

Superoxide during reperfusion contributes to caspase-8 expression and apoptosis after transient focal stroke.

BACKGROUND AND PURPOSE: Reactive oxygen species produced during reperfusion may play a detrimental role in focal cerebral ischemia (FCI). We examined the protein expression of caspase-8, which plays a major role in both Fas-dependent and cytochrome c-dependent apoptotic pathways after FCI with or without reperfusion. Caspase-8 expression after transient FCI was compared between wild-type and transgenic mice that overexpress the cytosolic antioxidant copper/zinc superoxide dismutase (SOD1). METHODS: Adult male CD-1 mice were subjected to 1 hour of FCI and reperfusion or to permanent FCI by intraluminal blockade of the middle cerebral artery. DNA fragmentation was evaluated by genomic DNA gel electrophoresis. Caspase-8 expression was analyzed by Western blot. RESULTS: Caspase-8 was significantly induced 4 hours after transient FCI and remained at an increased level until 24 hours, whereas it was not modified after permanent FCI. Genomic DNA gel electrophoresis showed DNA laddering in a pattern similar to that seen in apoptosis, with a small amount of background smear 24 hours after transient FCI, whereas 25 hours of permanent FCI resulted in less DNA laddering with a strong background smear. Caspase-8 induction was significantly reduced in SOD1 transgenic mice compared with wild-type mice 4 hours after transient FCI. CONCLUSIONS: The results suggest that increased reactive oxygen species production during reperfusion may contribute to the induction of caspase-8, thereby exacerbating apoptosis after FCI.

Animals↗
PubMed2001

Co-existing proteins interfere with the action of nordihydroguaiaretic acid on retrograde Golgi-to-ER protein trafficking in NRK cells and alpha-glucosidase reaction in vitro.

Induction of retrograde trafficking of mannosidase II and TGN38 in NRK cells and inhibition of alpha-glucosidase in vitro by nordihydroguaiaretic acid (NDGA) were strongly interfered with by serum, serum albumin, or other unrelated proteins added to the medium or incubation mixture. These observations indicate that NDGA interacts with diverse kinds of proteins, and therefore, pharmacological effects of NDGA at cellular levels should be carefully interpreted.

Animals↗
PubMed2001

Severe subarachnoid hemorrhage with pulmonary edema successfully treated by intra-aneurysmal embolization using Guglielmi detachable coils--Two case reports.

A 48-year-old male and a 39-year-old female presented with subarachnoid hemorrhage (SAH) due to ruptured anterior communicating artery aneurysms. Both patients were comatose on admission. Chest radiography disclosed pulmonary edema. They were conservatively treated under controlled ventilation, but cardiopulmonary dysfunction persisted over 2 days. The patients were then treated by intra-aneurysmal embolization with Guglielmi detachable coils (GDCs) 2 days after the onset. The postoperative courses were uneventful, and the patients showed full recovery from pulmonary edema and were discharged without neurological deficits. Neurogenic pulmonary edema is one of the serious complications of SAH, and is a leading cause of poor clinical outcome. The favorable outcomes of the present cases suggest that intra-aneurysmal embolization with GDCs is an excellent choice for the patients with severe aneurysmal SAH complicated with pulmonary edema, in whom conventional surgical treatment under general anesthesia is difficult to perform in the acute stage.

Adult↗
PubMed2001

Interhemispheric cyst causing leg monoparesis in the elderly--case report.

A 64-year-old female presented with a rare case of interhemispheric cerebral cyst manifesting as progressive monoparesis in the right lower extremity for 2 years. Surgical excision of the cyst wall was performed and communication to the subdural space was created. Postoperatively, the cyst was greatly reduced in size, and the neurological signs and symptoms were markedly improved. Interhemispheric cyst often presents with motor disturbances such as hemisparesis or paraparesis. These symptoms tend to progress slowly and sometimes years are required for a proper diagnosis. Interhemispheric cyst can also cause slowly progressive monoparesis in the lower extremity.

Arachnoid Cysts↗