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Y Honda

Publications and source records attributed to Y Honda.

At least 181 records · Page 10Linked to original sources
PubMed1999

Effect of immobilization on vitamin D status and bone mass in chronically hospitalized disabled stroke patients.

OBJECTIVE: To assess the influence of immobilization upon vitamin D status and bone mass in chronically hospitalized, disabled, elderly patients following stroke. DESIGN: cross-sectional study. SETTING: Department of geriatric neurology in a Japanese hospital. SUBJECTS: 129 chronically hospitalized, disabled, elderly stroke patients and 28 age-matched controls. RESULTS: We observed a deficiency of both 1,25-dihydroxyvitamin D (1,25-[OH]2D; 24.3 pg/ml) and 25-hydroxyvitamin D concentrations (25-OHD; 11.7 ng/ml) in stroke patients compared with controls. A high serum ionized calcium (mean; 2.648 mEq/l) was an independent determinant of the Barthel index (66) and 1,25-[OH]2D. When the patients were categorized into three groups by 25-OHD level (deficient, insufficient and sufficient), there was no difference in the mean 1,25-[OH]2D levels. Parathyroid hormone levels were normal or low and did not correlate with 25-OHD. Serum bone turnover variables and bone mineral density (BMD) of the second metacarpal in patients were significantly decreased compared to control subjects. Independent determinants of BMD included Barthel index, 25-OHD and 1,25-[OH]2D. CONCLUSIONS: 1,25-[OH]2D deficiency in immobilized stroke patients is not caused by substrate (25-OHD) deficiency but by hypercalcaemia. Immobilization-induced hypercalcaemia may inhibit parathyroid hormone secretion and thus 1,25-[OH]2D production, resulting in decreased BMD. Immobilization itself also may be responsible for decreased BMD. Exogenous 1,25-[OH]2D (calcitriol) rather than dietary vitamin D supplementation may be required in disabled elderly stroke patients who have a deficiency of 1,25-[OH]2D in order to prevent hip fractures, which frequently occur in this population.

Aged↗
PubMed1999

Chitosanase-catalyzed hydrolysis of 4-methylumbelliferyl beta-chitotrioside.

4-Methylumbelliferyl beta-chitotrioside [(GlcN)(3)-UMB] was prepared from 4-methylumbelliferyl tri-N-acetyl-beta-chitotrioside [(GlcNAc)(3)-UMB] using chitin deacetylase from Colletotrichum lindemuthianum, and hydrolyzed by chitosanase from Streptomyces sp. N174. The enzymatic deacetylation of (GlcNAc)(3)-UMB was confirmed by (1)H-NMR spectroscopy and mass spectrometry. When the (GlcN)(3)-UMB obtained was incubated with chitosanase, the fluorescence intensity at 450 nm obtained by excitation at 360 nm was found to increase with proportion to the reaction time. The rate of increase in the fluorescence intensity was proportional to the enzyme concentration. This indicates that chitosanase hydrolyzes the glycosidic linkage between a GlcN residue and UMB moiety releasing the fluorescent UMB molecule. Since (GlcN)(3) itself cannot be hydrolyzed by the chitosanase, (GlcN)(3)-UMB is considered to be a useful low molecular weight substrate for the assay of chitosanase. The k(cat) and K(m) values obtained for the substrate (GlcN)(3)-UMB were determined to be 8.1 x 10(-5) s(-1) and 201 microM, respectively. From TLC analysis of the reaction products, the chitosanase was found to hydrolyze not only the linkages between a GlcN residue and UMB moiety, but also the linkages between GlcN residues. Nevertheless, the high sensitivity of the fluorescence detection of the UMB molecule would enable a more accurate determination of kinetic constants for chitosanases.

Amidohydrolases↗
PubMed1999

Role of nitric oxide during the initial phase of reperfusion after retinal ischemia in the rat.

The onset of reperfusion and the recovery of the ERG b-wave following retinal ischemia was examined among three groups of rats: group 1 (n = 12) and group 2 (n = 6) received pretreatment with NG-nitro-L-arginine (20 mg/kg, i.p., 2 h before ischemia) followed by intravenous injection of saline (group 1) or of 200 mg/kg L-arginine (group 2) 5 min before the end of ischemia; group 3 (n = 7) received saline pretreatment followed by intravenous injection of saline as a control. Group 1 showed delayed onset of reperfusion compared to the other two groups and a reduction in the rate of the b-wave recovery compared to the control on the 1st day after reperfusion (group 1 vs. group 3; p = 0.0357). The L-arginine posttreatment significantly increased the b-wave recovery (group 2 vs. group 1; p = 0.0005 on day 1 and p < 0.0006 on day 3). The rate of the b-wave recovery in group 1 was inversely proportional to the time to establish complete reperfusion. Inhibition of nitric oxide synthase during the initial phase of reperfusion may worsen the recovery of the b-wave following retinal ischemia, at least in part, by inhibiting establishment of reperfusion.

Animals↗
PubMed1999

Synthesis of phenoxyacetic acid derivatives as highly potent antagonists of gastrin/cholecystokinin-B receptors. III.

In order to improve the biological characteristics of DA-3934 (5), a novel gastrin/cholecystokinin (CCK)-B receptor antagonist, phenoxyacetic acid derivatives replacing the N-methyl-N-phenylcarbamoylmethyl moiety of 5 with various alkyl chains have been synthesized and their biological activity evaluated. The relationship between the structure of these compounds and their human gastrin receptor binding affinity showed that there should be the optimal size among the various N-alkyl chains. Also a significant increase in the receptor binding affinity was achieved by several compounds. Among those compounds, 2-[3-[3- [N-cyclohexylmethyl-N-[2-(N-methyl- N-phenylcarbamoylmethoxy)phenyl]carbamoylmethyl]ureido]pheny l]acetic acid (22c) and (+/-)-2-[3-[3-[N-[2-(N-methyl-N- phenylcarbamoylmethoxy)phenyl]-N-(3-methylpentyl)carbamoy lmethyl]ureido] phenyl]acetic acid (22h) exhibited high affinity for human gastrin receptors and were also more potent inhibitors in a pentagastrin-induced gastric acid secretion model than the parent compound, 5. The ED50 values of these compounds when administered intraduodenally to rats were 0.12 and 0.63 mg/kg, respectively.

Acetates↗
PubMed1999

Dentocraniofacial morphology in parents of children with cleft lip and/or palate.

OBJECTIVE: The purpose of this study was to compare the dentocraniofacial morphology of parents of children with cleft lip and/or palate (CL/P) with that of parents of children without CL/P and to use the results for genetic counseling. PARTICIPANTS: Twenty-five fathers and 40 mothers of Japanese children with CL/P, who also had relatives with CL/P within three generations (experimental group), and 413 pairs of parents of children without CL/P (control) were used in this study. To test the accuracy of the discriminant function, 165 subjects were added to this study (test group). MATERIALS AND METHODS: Sixty-five dental casts were measured by digital sliding calipers, and 1056 frontal and 1056 lateral cephalograms were traced, digitized, and analyzed using analysis of variance (ANOVA) and discriminant analysis. RESULTS: Mesiodistal tooth diameters in parents of children with CL/P did not show any differences from those in parents of children without CL/P. The parents in the experimental group showed a distinct craniofacial morphology: wider interorbital width (IO-IO'), intercoronoid process distance (Cp-Cp'), and nasal cavity width (NC-NC') and larger anterior cranial base length (S-N) and cranial base length (N-Ba). For genetic counseling, a discriminant function was obtained using four significant ratios on ANOVA. The percentage of correct classification using this function on the pooled experimental and control subjects was 67.9. CONCLUSION: The parents in the experimental group showed a special craniofacial morphology, but the results suggest that the discriminant function might not be helpful in genetic counseling.

Adult↗
PubMed1999

[Sarcomatoid carcinoma of the urinary bladder in a hemodialysis patient: a case report].

The following is a case report bladder of sarcomatoid carcinoma in a Japanese 65-year old female patient treated with hemodialysis. She developed chronic renal failure due to chronic glomerulonephritis. Fifteen months after the beginning of the hemodialysis, continuous gross hematuria was noticed, and cystoscopy revealed a broad-based bladder tumor spreading from the right lateral wall to the posterior wall. The histopathologic diagnosis of the TUR-Bt specimens was sarcoma. Radical cystectomy was performed under the diagnosis clinical stage III, T3bN0M0. The post-operative histopathologic diagnosis of the tumor was sarcomatoid carcinoma, composed of nests of transitional cell carcinoma (G 3) and predominant areas of spindle cell sarcomatoid transformation. Sarcomatoid carcinoma of the bladder in a hemodialysis patient is extremely rare, and to date this may be only the second case in Japanese medical literature.

Aged↗
PubMed1999

[Management of mycobacteriosis in general hospital without isolation ward for tuberculosis patients. Clinical study on pulmonary tuberculosis associated with lung cancer patients].

Sixteen of 758 lung cancer in patients (2.1%) were found to have coexisting pulmonary tuberculosis. Of the above 16 of 758 patients (fifteen men and one woman), 4 of 214 patients (1.9%) were found from 1988 to 1989, and 12 of 544 patients (2.2%) from 1991 to 1994. In six patients, pulmonary tuberculosis and lung cancer were found at the same time by clinical work up. In five cases each, pulmonary tuberculosis preceded lung cancer, and lung cancer preceded pulmonary tuberculosis, respectively. Ten patients had adenocarcinoma, 4 had squamous cell carcinoma, and one each had large cell carcinoma and small cell carcinoma, respectively. Five patients were in stage "II", one in "IIIa", two in "IIIb", and eight in "IV" of clinical stage of lung cancer. As regards extent of pulmonary tuberculosis, one patient was in category "II" of the classification of the Japanese Society for Tuberculosis, 13 were in "III", and two were in "IV". Among 544 lung cancer patients from 1991 to 1994, 9 of 151 patients (6.0%) with a past history of pulmonary tuberculosis, had active pulmonary tuberculosis, and 3 of 393 patients (0.8%) with no history of pulmonary tuberculosis, had active pulmonary tuberculosis (statistically significant; p < 0.005). Five smear-positive patients were transferred to a tuberculosis hospital or a tuberculosis ward, and the remaining 11 patients were treated in isolation in the ward where they were. The efficacy of anti-tuberculous chemotherapy was almost comparable to that in patients without lung cancer. However, prognosis was poor, in line with that of lung cancer. Main discussion was devoted to the reason why the incidence (in association with tuberculosis) of adenocarcinoma exceeded that of squamous cell carcinoma in our present study at variance with the studies of other investigators.

Adenocarcinoma↗
PubMed1999

Retinal ischemia-reperfusion injury attenuated by blocking of adhesion molecules of vascular endothelium.

PURPOSE: To evaluate quantitatively the effects of blocking of adhesion molecules (P-selectin or intercellular adhesion molecule-1 [ICAM-1]) on leukocyte dynamics in the retinal microcirculation in vivo during ischemia-reperfusion injury and the therapeutic efficacy of the blocking of adhesion molecules on retinal ischemia-reperfusion injury. METHODS: Retinal ischemia was induced for 60 minutes in anesthetized pigmented rats by temporary ligation of the optic nerve. P-selectin or ICAM-1 monoclonal antibody (mAb) was administered at 5 minutes before reperfusion. At 4, 12, and 24 hours after onset of reperfusion, leukocyte behavior in the retinal microcirculation was evaluated in vivo with acridine orange digital fluorography. After 7 or 14 days of reperfusion, retinal damage was evaluated histologically. RESULTS: P-selectin mAb significantly inhibited leukocyte rolling along the major retinal veins after reperfusion. Subsequently, the number of accumulated leukocytes decreased in the P-selectin-inhibited rats. ICAM-1 mAb also inhibited leukocyte accumulation during the reperfusion period in a more substantial manner than P-selectin mAb. Histologic examination demonstrated the protective effect of the blocking of P-selectin or ICAM-1. In accordance with a reduction in leukocyte accumulation, the protective effect of mAb on retinal ischemia-reperfusion injury was more substantial in ICAM-1-inhibited rats. CONCLUSIONS: The present study demonstrates the inhibitory effect of P-selectin and ICAM-1 mAb on leukocyte accumulation and subsequent tissue injury during retinal ischemia-reperfusion injury.

Animals↗
PubMed1999

Radiation-induced leukocyte entrapment in the rat retinal microcirculation.

PURPOSE: To evaluate the effects of irradiation on leukocyte dynamics in the rat retinal microcirculation. METHODS: Thirty-five Brown-Norway rats received a dose of 10 Gy irradiation in one fraction. Leukocyte dynamics were studied with acridine orange digital fluorography, in which a nuclear fluorescent dye of acridine orange is used and examined by scanning laser ophthalmoscope. This technique allowed visualization of fluorescent leukocytes in vivo. The leukocyte dynamics were evaluated at 0, 4, 7, 14, 30, and 60 days after the irradiation. RESULTS: Mean leukocyte velocity in the retinal capillaries decreased immediately. It partially recovered on day 4 but then gradually decreased up to the 2-month mark. Low-dose irradiation induced entrapment of leukocytes in the retinal microcirculation. The number of entrapped leukocytes gradually increased with time. The major retinal vessels significantly constricted immediately after irradiation. The diameter was reduced by 76% in arteries and 75% in veins, 2 months after irradiation. CONCLUSIONS: Entrapped leukocytes may be activated and exacerbate vascular injury and microinfarction and thus may participate in the pathogenesis of radiation retinopathy.

Acridine Orange↗
PubMed1999

Effect of focal X-ray irradiation on experimental choroidal neovascularization.

PURPOSE: Radiation therapy has been used to treat choroidal neovascularization (CNV) in patients with age-related macular degeneration. The in vivo effect of applying focal x-ray irradiation to the eye of rabbits with experimental CNV was investigated. METHODS: CNV was induced in the rabbit eyes by subretinal implantation of gelatin hydrogel microspheres impregnated with basic fibroblast growth factor. Three weeks after implantation, 17 of 34 eyes with CNV lesions accompanied by fluorescein leakage were irradiated with a single dose of 20 Gy; the other 17 eyes were not irradiated and served as the controls. The eyes were examined before irradiation and 1, 2, and 4 weeks after irradiation, by indirect ophthalmoscopy and fluorescein angiography. The degree of a decreasing amount of fluorescein leakage from the CNV lesions after irradiation was graded using a computerized image analysis system and was compared in the irradiated and nonirradiated eyes. These eyes were also examined histologically and immunohistochemically. RESULTS: Fluorescein leakage from the CNV lesions had significantly decreased in the eyes irradiated with 20 Gy compared with the control eyes, throughout the study period (P < 0.05). Histologic and immunohistochemical studies at 4 weeks after irradiation demonstrated that the degree of vascular formation and the number of vascular endothelial cells in the subretinal membrane of the irradiated eyes were less than those of the control eyes. CONCLUSIONS: Focal x-ray irradiation at the ocular region effectively reduced experimental CNV activity. These results support the possibility that radiation therapy may be beneficial in treating CNV.

Animals↗
PubMed1999

Inhibitory effect of TNP-470 on experimental choroidal neovascularization in a rat model.

PURPOSE: To determine whether an angiogenic inhibitor, TNP- 470 (TNP), an analogue of fumagillin, inhibits choroidal neovascularization (CNV) induced by diode laser photocoagulation in a rat experimental model. METHODS: Fundus laser photocoagulation was performed on Brown Norway rats to induce CNV. In the treatment group, TNP was administered intraperitoneally at the time of laser photocoagulation and on day 7 (50 mg/kg at each time). The incidence of CNV formation was evaluated by fluorescein angiography. The retina was collected from the rats on days 1, 3, 7, and 14 after laser photocoagulation, and semiquantitative polymerase chain reaction (PCR) analyses for the expression of mRNA of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) were carried out. Localization of bFGF mRNA was studied by in situ reverse transcription-PCR (RT-PCR). The numbers of positively labeled cells for bFGF mRNA were compared between the TNP treatment and control groups. RESULTS: The incidence of CNV formation was 22.7% in the TNP-treated rats and that in the control rats was 61.4% (P < 0.001). The semiquantitative PCR analyses showed that bFGF mRNA was upregulated on days 3 and 7 in the control rats, but no significant changes were found in TNP-treated rats. There was no detectable difference in VEGF gene expression between the control and TNP-treated rats. bFGF mRNA was detected by in situ RT-PCR in the regenerated retinal pigment epithelial cells and cells of the outer and inner nuclear layers of the control rats. The number of positive cells for bFGF mRNA in the TNP treatment group was significantly smaller than that of the control group (P < 0.05) on days 3 and 14. CONCLUSIONS: TNP- 470 treatment reduced the incidence of laser-induced CNV formation in this experimental model. The expression of bFGF associated with CNV formation was also significantly reduced by the TNP treatment.

Animals↗
PubMed1999

Expression of proteoglycan decorin in neural retina.

PURPOSE: To identify the expression of chondroitin/dermatan sulfate proteoglycan decorin in retina and to elucidate its changes during development and ischemia-reperfusion. METHODS: Expression of decorin in rat retina was investigated by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Distributional changes during development and transient ischemia in model eyes also were investigated by immunohistochemical experiments. RESULTS: Gene expression of decorin core protein was identified in rat retina by RT-PCR. Decorin immunoreactivities were shown throughout the retina, especially in the ganglion cell layer. In developing rat retinas, at embryonic stages (embryonic day 16), decorin was distributed uniformly throughout the retina. As retina matured, the intensity of decorin immunostaining in retinal inner layers and retinal pigment epithelium increased. Furthermore, in experimental transient retinal ischemia, after transient downregulation of the decorin core protein gene between 24 and 48 hours after the ischemia, recovered (or increased) expression was shown by semiquantitative RT-PCR experiments. Immunohistochemical studies revealed strong decorin immunoreactivities in the damaged inner layers 1 week later. CONCLUSIONS: The expression of decorin was identified in adult and developing rat retina. The distributional changes of decorin during the retinal development suggest that this proteoglycan may play a role in the differentiation of retinal ganglion cells. Moreover, in rat ischemia-reperfusion models, the alterations in gene expression and immunohistochemical localization showed the contribution of this proteoglycan to the damage and repair processes in diseased retina.

Animals↗
PubMed1999

[A case of active pulmonary tuberculosis in the right lower lung field detected by CT].

Many studies have indicated the pitfalls in detecting abnormalities on chest radiography, although radiography of the chest has been used for the screening of peripheral lung cancer. Recently, mass screening with a spiral computed tomography scanner has been performed for the detection of small peripheral lung cancers, and it has been clarified that spiral CT was superior to chest radiography in the screening and detection of peripheral lung cancer. However, there have been only a few reports on pulmonary tuberculosis that was detected by chest CT. We report a case of active pulmonary tuberculosis detected by chest CT, and invisible on plain chest radiography. 39 year old female consulted our hospital, because chest radiography at mass screening for lung cancer showed an abnormal shadow in the left upper lung field. Chest CT revealed a high density nodule with calcification compatible with old tuberculosis. However, there was another 20 mm x 10 mm sized nodule in right S9b that was invisible on plain chest radiography. The nodule had a clear margin with satellite lesion that characterize active pulmonary tuberculosis. Bronchial lavage was performed by bronchofiberscopy, and Mycobacterium tuberculosis was isolated from lavage fluid. The nodular shadow disappeared after the treatment with isoniazid and rifampicin for 9 months.

Adult↗
PubMed1999

The daf-2 gene network for longevity regulates oxidative stress resistance and Mn-superoxide dismutase gene expression in Caenorhabditis elegans.

Longevity is regulated by the daf-2 gene network in Caenorhabditis elegans. Mutations in the daf-2 gene, which encodes a member of the insulin receptor family, confer the life extension (Age) phenotype and the constitutive dauer (a growth-arrested larval form specialized for dispersal) formation phenotype. The Age phenotype is mutually potentiated by two life extension mutations in the daf-2 gene and the clk-1 gene, a homologue of yeast CAT5/COQ7 known to regulate ubiquinone biosynthesis. In this study, we demonstrated that the daf-2 mutation also conferred an oxidative stress resistance (Oxr) phenotype, which was also enhanced by the clk-1 mutation. Similar to the Age phenotype, the Oxr phenotype was regulated by the genetic pathway of insulin-like signaling from daf-2 to the daf-16 gene, a homologue of the HNF-3/forkhead transcription factor. These findings led us to examine whether the insulin-like signaling pathway regulates the gene expression of antioxidant defense enzymes. We found that the mRNA level of the sod-3 gene, which encodes Mn-superoxide dismutase (SOD), was much higher in daf-2 mutants than in the wild type. Moreover, the increased sod-3 gene expression phenotype is regulated by the insulin-like signaling pathway. Although the clk-1 mutant itself did not display Oxr and the increased sod-3 expression phenotypes, the clk-1 mutation enhanced them in the daf-2 mutant, suggesting that clk-1 is involved in longevity in two ways: clk-1 composes the original clk-1 longevity program and the daf-2 longevity program. These observations suggest that the daf-2 gene network controls longevity by regulating the Mn-SOD-associated antioxidant defense system. This system appears to play a role in efficient life maintenance at the dauer stage.

Animals↗
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↗