Biomedical subjects

H Takagi

Publications and source records attributed to H Takagi.

At least 217 records · Page 12Linked to original sources

PubMed1999

Faropenem enhances superoxide anion production by human neutrophils in vitro.

Neutrophils are important cellular components in the defence against infections and many studies in vitro have shown that some antibiotics affect neutrophil function. We examined the effect of faropenem, a new oral penem antibiotic on neutrophil killing function by determining the generation of superoxide anion in vitro. The production of superoxide anion was measured by chemiluminescence amplified by a Cypridina luciferin analogue in the presence of N-formyl-Met-Leu-Phe (fMLP). Faropenem significantly enhanced chemiluminescence in a dose-dependent manner. The effect of faropenem was maximal at 5 min of incubation time and continued for at least 30 min. The effect of faropenem was also observed when neutrophils were stimulated by a calcium ionophore (ionomycin), while the effect of faropenem did not change in the presence of 12-O-tetra-decanoylphorbolmyristate acetate. Cytosol Ca2+ concentration ([Ca2+]i) monitored with Fura-2 increased in response to fMLP, however, faropenem did not influence the response of [Ca2+]i to fMLP. Our results suggest that faropenem enhanced the generation of superoxide anion by neutrophils, probably at the site where cytosol Ca2+ regulates NADPH oxidase. Faropenem might be potentially advantageous in the treatment of infections because a synergic interaction of antibodies and cytocidal neutrophils is necessary for the early eradication of the pathogenic bacteria.

Anti-Bacterial Agents↗

PubMed1999

Quantitative analysis of diabetic macular edema after scatter laser photocoagulation with the scanning retinal thickness analyzer.

PURPOSE: To define the effect of scatter laser photocoagulation on foveal retinal thickness. METHODS: A commercial scanning retinal thickness analyzer was used to measure retinal thickness. The foveal retinal thickness was measured at the central area of the fundus (0.4 x 0.4 mm). The method was applied to 20 consecutive patients (mean age, 52.4 +/-16.9 years) with diabetic retinopathy. Measurements were performed before and 6 weeks after scatter photocoagulation. Patients were examined by fluorescein angiography and slit-lamp biomicroscopy to detect macular edema. RESULTS: Mean foveal thickness before scatter photocoagulation was 187+/-45 microm, increasing to 221+/-46 microm after the treatment (P = 0.0001). The foveal thickness increased in 12 eyes (60%). Laser treatment increased macular permeability in two eyes (10%). Biomicroscopic examination revealed central macular thickening in one eye (5%). Visual acuity was reduced in four eyes (20%). CONCLUSIONS: Our results suggest that subclinical macular edema occurs after scatter laser photocoagulation. The retinal thickness analyzer is a sensitive tool for early detection of macular edema after laser treatment, because increases in retinal thickness as small as 34 microm cannot be assessed by slit-lamp biomicroscopy.

Capillary Permeability↗

PubMed1999

Clinical and immunological characterization of patients with systemic sclerosis overlapping primary biliary cirrhosis: a comparison with patients with systemic sclerosis alone.

Limited cutaneous systemic sclerosis (lSSc) or CREST syndrome is sometimes complicated by primary biliary cirrhosis (PBC). To characterize the clinical and immunological features of patients with SSc overlapping PBC (SSc-PBC), the clinical and laboratory data of 11 SSc-PBC were studied. Since all of the SSc-PBC were lSSc, the features of SSc-PBC were compared with those of 266 patients with lSSc alone. The sera from SSc-PBC showed a significantly higher positivity for anti-centromere antibody (ACA) (p < 0.0005) and higher reactivity to centromere protein-C. Although SSc-PBC more frequently exhibited calcinosis and telangiectasia (p < 0.05), there was no statistical difference in other features of CREST syndrome. There was no statistical difference in other scleroderma-related features either. SSc-PBC were more frequently complicated with Sjögren syndrome (p < 0.05). The most prominent feature of SSc-PBC was a higher incidence of ACA than in lSSc alone.

Adult↗

PubMed1999

Prevalence of hepatitis G virus in liver disease.

The prevalence of hepatitis G virus (HGV) in liver disease of non-A, -B, -C viral hepatitis, hepatitis B and hepatitis C was determined. Two of 44 patients (4.5%) with liver injury without any hepatitis A, B or C marker were positive for HGV. One of five cases of hepatocellular carcinoma was positive for HGV. One of three cases with fulminant hepatitis was positive for HGV. This case was negative at the onset of fulminant hepatitis and became positive after plasmapheresis. No patient with acute (n=8) or chronic (n=5) hepatitis or liver cirrhosis (n=8) was positive for HGV in non-A, -B, -C liver disease. One of 30 patients with various HBV-positive liver diseases and nine (17.3) of 52 patients with type C liver disease were positive for HGV. In patients with hepatitis C, four (28.6%) of 14 HGV-co-infected patients were complicated with diabetes mellitus compared with four (10.5%) of 38 single hepatitis C virus (HCV)-infected patients (not significant). In 12 HGV-positive patients, eight of 10 (80%) had a history of blood transfusion. In HCV-positive patients, co-infection with HGV was not a risk factor in patients with diabetes mellitus as a complication. HGV appeared to cause non-A, -B, -C hepatitis rarely, and its main route of infection was blood transfusion.

Adolescent↗

PubMed1999

Mesalazine-induced eosinophilic pneumonia.

A 35-year-old woman with a 6-month history of ulcerative colitis and treatment with oral mesalazine (5-aminosalicylic acid) developed dry cough, low-grade fever and bilaterally wandering pulmonary infiltrates. Improvement in clinical symptoms and radiological abnormalities occurred spontaneously after discontinuation of mesalazine. The transbronchial lung biopsy demonstrated the organizing stage of eosinophilic pneumonia. Drug lymphocyte stimulation test was positive for mesalazine and negative for sulfasalazine and sulfapyridine. The present case indicates that although mesalazine-induced eosinophilic pneumonia is an extremely rare entity, its possibility should be fully considered in patients developing unexplained respiratory symptoms while on mesalazine therapy.

Adult↗

PubMed1999

Structural conversion from non-native to native form of recombinant human epidermal growth factor by Brevibacillus choshinensis.

Brevibacillus choshinensis (Bacillus brevis) HPD31 is a very efficient producer of recombinant human epidermal growth factor (EGF). The produced EGF is secreted into the medium with high efficiency. However part of the EGF that accumulates in the medium, exists as multimeric forms which are biologically inactive. We found the bacterium has the activity to structurally convert multimeric forms to the monomeric, native ones. Optimal temperature and pH for the conversion were 40 degrees C and pH 9, respectively. The reaction was promoted in the presence of reduced glutathione or cysteine. But the cells which had been sonicated or exposed to moderate heat treatment completely lost the activity. Thus, it was presumed that the activity might be due to the enzyme(s) that catalyze the protein disulfide exchanging reaction, and that they resides on the surface of viable cells.

Bacillus↗

PubMed1999

Time course observation of thyroid proliferative lesions and serum levels of related hormones in rats treated with kojic acid after DHPN initiation.

Time course changes in thyroid proliferative lesions as well as related hormone levels in the blood of male F344 rats given N-bis(2-hydroxypropyl)nitrosamine (DHPN: 2800 mg/kg body weight, single s.c. injection) as an initiation treatment followed by pulverized basal diet containing 0% (Group 2), 2% (Group 3) or 4% (Group 4) kojic acid (KA) were examined at Weeks 1, 2, 4, 8 and 12. As an untreated control group (Group 1), rats were given basal diet for 13 weeks and examined in the same manner. Serum T3/T4 levels in the DHPN + 2% KA and DHPN + 4% KA groups were significantly reduced as compared with the DHPN-alone group at each time point. Serum TSH levels in both DHPN + KA groups were significantly increased at each time point in a treatment period-dependent manner from Weeks 1 to 12, and the extent of elevation was more remarkable in the DHPN + 4% KA group. At Week 2, there were no statistically significant intergroup differences in liver T4-UDP-GT activities on a milligram microsomal protein basis. Histopathologically, no thyroid proliferative lesions were observed in the untreated control group or the DHPN-alone group. However, diffuse follicular cell hypertrophy and decreased colloid in the thyroid were apparent in all rats of the DHPN + KA groups at each time point. In addition, focal follicular cell hyperplasias and adenomas of the thyroid were observed at high incidence in the DHPN + 2% KA group from Week 4 and in the DHPN + 4% KA group from Week 8. Multiplicities of focal follicular cell hyperplasias and adenomas of the thyroid in the DHPN + 2% KA group were significantly greater than those in the DHPN + 4% KA group at Week 8. In the pituitary, an increase in the number of TSH producing cells with expanded cytoplasm was apparent from Weeks 4 to 12 in both DHPN + KA groups. These results strongly suggest that thyroid proliferative lesions were induced by KA administration due to continuous serum TSH stimulation through the negative feedback mechanism of the pituitary-thyroid axis, resulting from depression of serum T3 and T4.

Adenoma↗

PubMed1999

Fifteen-year follow-up of a heterozygous Fabry's disease patient associated with pre-excitation syndrome.

A 47-year-old woman with heterozygous Fabry's disease with pre-excitation syndrome has been followed up for 15 years. Diagnosis was confirmed by the typical electron microscopic feature of the endomyocardial specimen and a decreased plasma alpha-galactosidase activity. As the disease progressed, the interventricular septum thickened from 11 to 17 mm as measured by echocardiography, while the AH interval was prolonged from 80 to 140 msec. In Fabry's disease, the PR interval has been reported to be variable from short PR to AV block. Therefore, this case may be helpful to understand the time course in the AV conduction abnormalities with the progression of Fabry's disease.

Biopsy↗

PubMed1999

Bow hunter's stroke associated with an aberrant course of the vertebral artery--case report.

A 53-year-old male presented with repeated vertebrobasilar insufficiency on turning the head to the left. Angiography revealed severe stenosis of the dominant right vertebral artery at the atlantoaxial level in this position. Decompression surgery for the affected vertebral artery at the transverse foramen of the atlas was planned. However, surgery revealed an aberrant course of the artery, turning at the orifice of the transverse foramen of the atlas and perforating the dura at the occipitoatlantal level after passing through the bony canal of the atlas. Therefore, decompression was performed at the bony canal, which was the contributing site, and the symptoms improved. Bow hunter's stroke may be caused by atlantoaxial arterial anomalies, so accurate preoperative evaluation of the region is necessary to avoid anatomical confusion at surgery.

Atlanto-Axial Joint↗

PubMed1999

Using helical CT to evaluate renal cell carcinoma in patients undergoing hemodialysis: value of early enhanced images.

OBJECTIVE: The purpose of this study was to evaluate early and delayed enhanced helical CT for revealing renal cell carcinoma in patients undergoing hemodialysis. MATERIALS AND METHODS: Over the course of 3 years, 630 chronic hemodialysis patients underwent early and delayed contrast-enhanced and unenhanced helical CT to detect renal cell carcinoma. Retrospective review showed that 23 of these patients later underwent either unilateral or bilateral nephrectomy. Two radiologists, unaware of the pathology results, independently reviewed these 23 examinations. The sensitivity and specificity of each early and delayed scan for revealing neoplasms were determined using pathology as the gold standard. The mean attenuation values of the neoplasms and parenchymas of end-stage kidneys on both early and delayed enhanced images were also compared. RESULTS: Helical CT revealed 225 lesions, 24 of which were found to be renal cell carcinomas at pathology. Delayed enhanced helical CT failed to detect one papillary carcinoma in an end-stage kidney with acquired cysts. Three nonpapillary carcinomas were not detected on delayed scans, and one was missed on an early scan of a patient without acquired cysts. The sensitivity and specificity of early enhanced CT for revealing renal cell carcinoma were 96% and 95%, respectively. In contrast, delayed enhanced CT achieved a sensitivity of 83% and a specificity of 94%. A significant difference in mean attenuation values between carcinomas and renal parenchymas was observed on the images with early enhancement but not on those with delayed enhancement (p < .0001). CONCLUSION: Early enhanced helical CT is superior to delayed enhanced helical CT for revealing renal cell carcinoma in end-stage kidneys.

Carcinoma, Renal Cell↗

PubMed1999

Brasilicardin A, a new terpenoid antibiotic from pathogenic Nocardia brasiliensis: fermentation, isolation and biological activity.

A novel tricyclic diterpenoid antibiotic, brasilicardin A, was isolated from the culture broth of Nocardia brasiliensis IFM 0406. The antibiotic exhibited immunosuppressive activity in a mouse mixed lymphocyte reaction (MLR) assay system and its IC50 value was 0.057 microg/ml. Although the inhibitory activity of cyclosporin A (CyA) against IL-2 production was confirmed in the MLR assay system, brasilicardin A did not have the activity. The results of in vitro toxicity testing of brasilicardin A against various human cell lines were compared with those of CyA.

Aminoglycosides↗

PubMed1999

Tissue response of a small saccular aneurysm after incomplete occlusion with a Guglielmi detachable coil.

A 49-year-old woman had a small saccular aneurysm that was incompletely occluded with a Guglielmi detachable coil (GDC). She died from rupture of another aneurysm 42 days after the treatment. Autopsy for the embolized aneurysm revealed no neoendothelium at the aneurysmal neck, but an organized thrombus was observed limited to the periphery of the aneurysmal lumen. Although isolation of the aneurysm was not apparent, loose embolization with this method may help to reinforce the aneurysmal wall.

Aneurysm, Ruptured↗

PubMed1999

The potential angiogenic role of macrophages in the formation of choroidal neovascular membranes.

PURPOSE: To investigate the distribution of inflammatory mediators such as interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha and angiogenic cytokines such as vascular endothelial growth factor (VEGF) and to identify their cellular source in surgically excised choroidal neovascular membranes (CNVMs) of various origins. METHODS: Immunoperoxidase staining was performed on paraffin-embedded sections of 11 surgically excised CNVMs to identify cellular distribution and localization of cytokines. Immunofluorescent double staining was performed to detect the cellular source of cytokines. RESULTS: Cytokeratin-positive cells were detected in the RPE layer, in stromal cells, and around neovascular vessels. Macrophages identified by their cellular marker CD68 showed almost the same distribution as cytokeratin-positive cells, although they were most prominent in the stroma. A substantial number of neovascular vessels were also immunoreactive to IL-1beta and TNF-alpha. Immunofluorescent double staining revealed that the RPE layers immunopositive for cytokeratin were also immunopositive for all cytokines, whereas stromal cells immunostained for CD68 were positive for IL-1beta and TNF-alpha, but not for VEGF. CONCLUSIONS: These results indicate that IL-1beta and TNF-alpha secreted by macrophages may promote, at least in part, angiogenesis in CNVMs by stimulating VEGF production in RPE cells.

Adult↗

PubMed1999

Expressions of angiopoietins and Tie2 in human choroidal neovascular membranes.

PURPOSE: To elucidate the potential role of angiopoietins and the Tie2 system in choroidal neovascularization. METHODS: Surgically excised choroidal neovascular membranes (CNVMs) were obtained at vitrectomy from five eyes with age-related macular degeneration, three eyes with idiopathic neovascular maculopathy, and two eyes had degenerative myopia and two eyes had angioid streaks. Light microscopic immunohistochemistry was performed to detect cytokines such as vascular endothelial growth factor (VEGF), Ang1, and Ang2 and cellular components such as retinal pigment epithelial (RPE) cells, macrophages, and endothelial cells. Immunofluorescent double staining using confocal microscopy was performed to identify the cell types that secrete specific cytokines. RESULTS: Ang1 and Ang2 were positive in all surgically excised CNVMs, regardless of the primary disease. Double staining revealed that many of the cytokeratin, CD68 and factor VIII positive cells also had Ang1 and Ang2 immunoreactivities. In contrast to Ang1, Ang2 immunoreactivity tends to be higher in the highly vascularized regions of many CNVMs, and the localization was very similar to that of VEGF staining. Almost all vascular structures had prominent immunoreactivity for Tie2, which was confirmed by double staining for Tie2 and factor VIII. Tie2 immunoreactivity was also observed in the RPE monolayer and in pigmented, polygonal, and fibroblast-like cells in the stroma. CONCLUSIONS: Present findings that Ang2 and VEGF are co-upregulated and that Tie2 is expressed in a variety of cell types in CNVMs further support a crucial role of the interaction between VEGF and Ang2 in pathologic angiogenesis of CNVM formation.

Adult↗

PubMed1999

17 Beta-estradiol increases VEGF receptor-2 and promotes DNA synthesis in retinal microvascular endothelial cells.

PURPOSE: Estrogen is known to promote angiogenesis in gonads. The presence of estrogen receptors in the vascular endothelium of organs other than gonads has been reported. The goal of this study was to determine whether estrogen promotes the proliferation of retinal microvascular endothelial cells and to explore the mechanism of it. METHODS: DNA was quantitated using primary cultures of bovine retinal endothelial cells that were incubated with different doses of 17 beta-estradiol (E2), VEGF, or both. The changes in expression level of VEGF and VEGF receptor-2 (VEGFR2) were measured using northern blot analysis after treatment with E2. The presence of estrogen receptors in the endothelial cells was studied by immunohistochemistry and western blot analysis. RESULTS: 17 Beta-estradiol (E2) increased the DNA level in bovine retinal capillary endothelial cells (BRECs) by 177% at 1 nM (P < 0.05) and 150% at 10 nM (P < 0.05) by comparison with unstimulated BREC. One hundred nanomole tamoxifen completely blocked the E2-induced DNA synthesis in BRECs. Ten nanomole E2 augmented vascular endothelial growth factor (VEGF)-induced DNA synthesis in BRECs significantly (160%, P < 0.01). Ten nanomole E2 also increased VEGF mRNA expression, which peaked after 24 hours (6.7 times, P < 0.05), and VEGF receptor-2 (VEGFR2) mRNA expression, which peaked after 9 hours (2.4 times, P < 0.05). The mRNA expression level of VEGFR2 peaked with 10 nM E2 (P < 0.05) and that of VEGF reached maximum with 1 nM E2 (15 times, P < 0.001). VEGFR2 and VEGF proteins increased in parallel with their mRNA levels. Immunocytochemistry showed estrogen receptor expression in BRECs, and western blot analysis indicated the presence of a 67-kDa protein that was compatible with the estrogen receptor. CONCLUSIONS: These findings suggest that E2 may stimulate BREC growth by the receptor-mediated pathway and that E2 may augment the VEGF-dependent angiogenesis partly through the upregulation of VEGFR2.

Animals↗

PubMed1999

[Autoimmune thyroid disease induced by interferon therapy].

Interferon therapy, widely used in chronic viral hepatitis and in various malignant diseases, has been known to induce autoimmune phenomena, the most frequent being autoimmune thyroid disease. We have studied the human leukocyte antigen (HLA) in patients who developed autoimmune thyroid dysfunction after interferon-alpha therapy for chronic hepatitis C. Seventeen of 439 patients (3.9%) developed symptomatic autoimmune thyroid dysfunction after interferon-alpha therapy, including nine cases of hyperthyroidism and eight cases of hypothyroidism. The incidence of HLA-A2 in those patients was significantly higher than that in general population in Japan. The present results suggest that HLA-A2 is associated with interferon-alpha therapy-induced autoimmune thyroid dysfunction in patients with chronic hepatitis C.

Autoimmune Diseases↗

PubMed1999

[A 13-week subchronic oral toxicity study of Perilla extracts in F344 rats].

A 13-week subchronic oral toxicity study of Perilla extracts in drinking water containing 0%, 2.5%, 5% and 10% extracts was performed in both sexes of F344 rats. Rats were randomly divided into 4 groups each consisting of 10 males and 10 females. No animals died during the period of administration. There were no treatment-related changes in body weight gain or in hematological or blood biochemistry values. Nor were any treatment-related histopathological changes observed in the highest dose group. These findings indicate that ingestion of 10% Perilla extracts in drinking water for 13-week does not cause any toxicological changes in rats.

Administration, Oral↗

PubMed1999

[13-week subchronic oral toxicity study of ammonium sulfate in rats].

A 13-week subchronic oral toxicity study of ammonium sulfate was performed in both sexes of F344 rats by feeding them a CRF-1 powder diet containing concentrations of 0%, 0.38%, 0.75%, 1.5%, and 3.0% of the substance. Rats were randomly divided into 5 groups each consisting of 10 males and 10 females. Male animals in the 3% group exhibited diarrhea during the administration period. No changes indicating obvious ammonium sulfate toxicity were observed in the body weights, organ weights, hematological, serum biochemical, or histopathological examinations. Based on these results, the NOEL (no-observed-effect level) of ammonium sulfate for F344 rats was judged to be 1.5% in males (886 mg/kg/day) and 3% in females (1975 mg/kg/day), and the MTD (maximally tolerated dose) for 2-year carcinogenicity studies in F344 rats was concluded to be 3.0% or more in the diet.

Ammonium Sulfate↗