Search PubMed⌕ Search

Biomedical subjects

S Nakajima

Publications and source records attributed to S Nakajima.

At least 127 records · Page 7Linked to original sources
PubMed1999

Selective occlusion of choroidal neovascularization by photodynamic therapy with a water-soluble photosensitizer, ATX-S10.

BACKGROUND AND OBJECTIVE: To determine the optimal treatment parameters for selective occlusion of choroidal neovascularization (CNV) by photodynamic therapy (PDT) by using the photosensitizer ATX-S10 and a diode laser (wavelength = 670 nm). MATERIALS AND METHODS: Experimental CNV was induced in rat fundi by argon laser photocoagulation. The distribution of ATX-S10 in the chorioretina was analyzed by fluorescence microscopy, and the optimal treatment parameters for selective occlusion of CNV were investigated by changing the dosage and timing of laser irradiation. CNV closure and resulting damage of the surrounding tissue were documented by fluorescein angiography and light and electron microscopies. RESULTS: Fluorescence of ATX-S10 was observed to be localized in the vascular lumen of the retina and choroid within 5 min after dye injection and increased in intensity in CNV up to 2-6 h and decreased rapidly in normal tissue. Laser irradiation with radiant exposures of 7.4 J/cm2 applied immediately after dye injection or with 22.0 J/cm2 at 2-4 h later effectively occluded the induced CNV without causing significant damage to normal retinal capillaries and large choroidal vessels. CONCLUSIONS: PDT using ATX-S10 can selectively occlude CNV. ATX-S10 is a potentially useful photosensitizer for the treatment of CNV.

Animals↗
PubMed1999

Summation of overshadowing and latent inhibition in rats' conditioned taste aversion: scapegoat technique works for familiar meals.

In rats' taste aversion learning, presentation of another taste with a target taste alleviates aversion for the target taste (overshadowing), and exposure of a target taste prior to its conditioning alleviates aversion for that taste (latent inhibition). The present study demonstrated summation of these effects, resulting in the least aversion in the rats that had received both overshadowing and latent inhibition treatments. The finding that overshadowing and latent inhibition summate is contrary to the prediction by the comparator hypothesis that they counteract, as recently reported in conditioned suppression of licking in thirsty rats. The present result supports the employment of the so-called "scapegoat technique" in cancer patients receiving chemotherapy after taking familiar meals.

Analysis of Variance↗
PubMed1999

Immunohistochemical analysis of cyclooxygenase-2 expression in pancreatic tumors.

BACKGROUND: A considerable amount of evidence collected from several experimental systems and clinical studies with nonsteroidal Anti-inflammatory drugs (NSAIDs) indicates that Cox-2 may play a major role in colorectal tumorigenesis, but little information about Cox-2 expression in pancreatic tumors is available. In this study, we investigated Cox-2 expression by means of both immunohistochemical analysis and immunoblot analysis in pancreatic tumors. METHODS: Fifty invasive ductal adenocarcinomas and 26 intraductal papillary-mucinous tumors (IPMTs) were used for immunohistochemical analysis, and five pancreatic cancer tissues and five pancreatic cancer cell lines for immunoblot analysis. RESULTS: Cox-2 was expressed in 72% of the invasive ductal adenocarcinomas, 31% of intraductal papillary-mucinous adenocarcinomas, and none of intraductal papillary-mucinous adenomas. The expression rate of Cox-2 in intraductal papillary-mucinous adenocarcinomas was significantly higher than that in intraductal papillary-mucinous adenomas, and that in invasive ductal adenocarcinomas was significantly higher than that in intraductal papillary-mucinous carcinomas. However, there was no significant correlation between Cox-2 expression and the prognosis and clinicopathological factors. Immunoblot analysis identified Cox-2 in all of pancreatic cancer tissues and 60% of cell lines. CONCLUSION: The biological role of cyclooxygenase-2 (Cox-2) in carcinoma cells should be investigated with reference to the cancer progression of the pancreas.

Adenocarcinoma↗
PubMed1999

Analysis of the stable levels of messenger RNA derived from different polymorphic alleles in the vitamin D receptor gene.

The association between polymorphisms in the vitamin D receptor (VDR) gene and bone mineral density (BMD) has been studied by many investigators. However, the question of how polymorphisms in the gene modulate the function of the VDR remains to be answered. To address this issue, we examined the mRNA levels of the VDR in relation to polymorphisms. First, we compared the levels of mRNA between the allele with the polymorphic TaqI-digestive site (t) and nondigestive site (T) located at exon 9 of the VDR gene determined by reverse transcription-polymerase chain reaction (RT-PCR). Total RNA was extracted from peripheral mononuclear cells in volunteers whose genotype is Tt. After the amplification of cDNA by PCR, the amplified fragments were digested by TaqI. The digested (t) and undigested (T) fragments were visualized by ethidium bromide and semiquantified by an image analyzer. In 24 subjects, the mRNA levels of allele t were significantly higher than those of allele T (1.35 fold, P < 0.001). Second, the VDR mRNA levels were estimated by competitive RT-PCR in 60 healthy subjects (35TT, 24Tt, 1 tt). The competitive template was 47 bases shorter than the product of the wild-type gene. After RT-PCR, the mRNA level was determined by a comparison with the competitive fragments. No significant difference in the mRNA level was observed between two groups (1.75 +/- 0.84 and 1.65 +/- 0.99 10(-13)mol/g total RNA in TT and Tt, respectively). In addition, no significant relationship was observed between the VDR mRNA levels and BMD in the 23 subjects whose BMD data were available. In conclusion, higher mRNA levels of allele t than T were detected, but the difference did not result in higher levels of VDR mRNA in subjects with the Tt genotype compared to those with the TT genotype.

Adult↗
PubMed1999

Oral contraceptives and smoking, current considerations: recommendations of a consensus panel.

In a closed meeting, members of the consensus panel evaluated the presentations of the scientific panel and developed a series of recommendations. They outlined clinical imperatives related to the identification and education of patients who smoke, the physician's role in smoking cessation, and the prescription of oral contraceptives for patients who smoke. They also outlined research objectives for the future. The most important suggestions include the following: All patients should be asked about their smoking status at every visit, and all smokers should be encouraged and helped to quit. The decision to prescribe an oral contraceptive requires a detailed personal and family history of thrombotic disease. Measurement of lipid profile should be considered, along with exercise and dietary intervention, for smokers >35 years old who use or request oral contraceptives. Patients >35 years old who smoke heavily (>15 cigarettes/d) should be denied the use of oral contraceptives. Preliminary data suggest that an oral contraceptive with the very low dose of 20 micrograms ethinyl estradiol may be safer for oral contraceptive users who smoke, even for those >35 years old who have an occasional cigarette, but these laboratory findings require clinical corroboration.

Cardiovascular Diseases↗
PubMed1999

Calcium phosphate-mediated transfection of primary cultured brain neurons using GFP expression as a marker: application for single neuron electrophysiology.

We investigated the efficiency of transfecting primary cultured rat postnatal brain neurons (substantia nigra pars compacta neurons and locus coeruleus neurons) with cDNA encoding GFP (jellyfish green fluorescent protein) using a calcium phosphate method. The proportion of transfected neurons (transfection efficiency) was approximately 5%, when cultures from the substantia nigra pars compacta were transfected 3 days after plating. The transfection efficiency decreased when cultures were transfected 10 days after plating (1.7%). Neurons were cotransfected at a very high probability ( > 78%) with the muscarinic m2-receptor cDNAs together with GFP plasmids. Transfected neurons were very healthy as indicated by the zero-current potential and the microscopical appearance. Because the transfection efficiency is low, this method cannot be used for experiments involving the whole cell population. The transfection efficiency of 1.7% corresponded to approximately 20 transfected cells per dish in our culture conditions and these cells are sufficient in number for electrophysiological studies. Therefore, this is an excellent method for studying the influence of exogenous genes on single neurons using electrophysiological techniques.

Animals↗
PubMed1999

Role of Bcl-2 family proteins (Bax, Bcl-2 and Bcl-X) on cellular susceptibility to radiation in pancreatic cancer cells.

The aim of this study was to examine Bax, Bcl-2 and Bcl-XL proteins in human pancreatic cancer cell lines and to clarify the mechanism of radiation resistance. PANC-1 and AsPC-1 pancreatic cell lines were used, both having mutated p53. Radioresistant PANC-1/Rad cells and AsPC-1/Rad cells were obtained by repeated 5 Gy irradiation of PANC-1 cells and AsPC-1 cells, respectively. Radiation was found to inhibit the growth of PANC-1 cells and AsPC-1 cells. After exposure to radiation, detached cells were subjected to FITC-TUNEL staining to calcualte the ratio of apoptosis. TUNEL positive ratios increased dose-dependently in both cell lines. Western blotting showed that the basal level of the Bax/Bcl-2 ratio reflected the radiosensitivity of these cell lines, and Bax expression was obviously upregulated after irradiation in the presence of mutated p53, but Bcl-2 expression remained almost constant. Both PANC-1/Rad and AsPC-1/Rad cells had greater Bcl-XL expression than the parental cells, and the basal level of the Bax/Bcl-2 ratio was no longer predictive of radiosensitivity. Upregulated expression of Bax protein after irradiation was not related to induction of apoptosis in these cells, suggesting that overexpression of Bcl-XL and functional reconstruction of Bcl-2 family proteins are important factors in acquired radioresistance.

Blotting, Western↗
PubMed1999

Effect of prolonged administration of a urinary kinase inhibitor, ebelactone B on the development of deoxycorticosterone acetate-salt hypertension in rats.

The effect of prolonged administration of a carboxypeptidase Y-like kininase inhibitor, ebelactone B (EB) (2-ethyl-3, 11-dihydroxy-4, 6, 8, 10, 12-pentamethyl-9-oxo-6-tetradecenoic 1, 3-lactone), on the development of deoxycorticosterone acetate (DOCA)-salt hypertension was tested. The systolic blood pressure (SBP) of non-treated 6-week-old Sprague-Dawley strain rats was gradually increased by DOCA-salt treatment from 137+/-2 mmHg (n=11) to 195+/-7 mmHg at 10 weeks of age. With daily oral administration of lisinopril (5 mg kg(-1), twice a day), which is an inhibitor of angiotensin converting enzyme, a major kininase in plasma, the development of hypertension was not suppressed. By contrast, administration of EB (5 mg kg(-1), twice a day), completely inhibited the development of hypertension (SBP: 146+/-1 mmHg, n=5, 10 weeks old). The reduced SBP at 10 weeks of age was equal to the SBP before any treatment (142+/-1 mmHg, n=5). Direct determination of mean blood pressure (MBP) in conscious, unrestrained rats confirmed that MBP elevation was completely inhibited by EB. Continuous subcutaneous infusion (5 mg kg(-1) day(-1)) of HOE140, a bradykinin B2 receptor antagonist, restored the elevation of SBP, which was suppressed by EB. The weights of left ventricle of DOCA-salt treated rats 10-weeks-old (0.36+/-0.02 g 100 g body weight(-1), n=11) was significantly reduced by EB (0.27+/-0.01, n=5), as were the sodium levels in serum, cerebrospinal fluid and erythrocyte. These findings suggested that EB is effective in preventing salt-related hypertension presumably by eliminating sodium retention.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Effects of ONO-1078 (pranlukast) on cytokine production in peripheral blood mononuclear cells of patients with bronchial asthma.

BACKGROUND: ONO-1078 (pranlukast) is a leukotriene receptor antagonist developed in Japan. This drug has been shown to be useful in oral treatment of bronchial asthma. The present study was undertaken to assess the effects of this drug on the production of cytokines in the peripheral blood mononuclear cells of patients with asthma under stimulation with specific antigens. METHODS: Peripheral blood mononuclear cells from mite antigen-positive asthmatic patients (immunoglobulin E RAST score > 3) were incubated for 72 h in the presence of mite antigen (10 microg/mL). The supernatant of the culture was subjected to enzyme-linked immunosorbent assay (ELISA) to quantify interleukin (IL) -4, IL-3, IL-5, and granulocyte macrophage-colony stimulating factor (GM-CSF). Other peripheral blood mononuclear cells from the same patients were incubated for 72 h in the presence of both mite antigen (10 microg/mL) and ONO-1078 (0.5, 1, or 10 microg/mL), followed by ELISA of the supernatant to quantify the cytokines. RESULTS: Production of IL-4, IL-5, and GM-CSF by mononuclear cells under stimulation with mite antigen was markedly suppressed when they were exposed to ONO-1078 at a concentration of 10 microg/mL. CONCLUSION: The results suggest that ONO-1078 acts directly on peripheral blood mononuclear cells and that blockade of leukotriene receptors on blood mononuclear cells by the cysteinyl-leukotriene receptor antagonist (LTRA) pranlukast (ONO-1078) can dose-dependently inhibit release of immunoreactive TH2-type cytokines (IL-3, IL-4, GM-CSF, and possibly IL-5), but not of the TH1-type cytokine IL-2, when stimulated by mite allergen in vitro. The data may provide clues to the mechanism by which a number of LTRA including zafirulukast and montelukast can reduce airway, sputum and blood eosinophil counts in clinical asthma. It supports animal studies showing that anti-IL-5 antibodies partially block cys-LT-induced airway eosinophilia, suggesting that cys-LTs may cause secondary release of IL-5 from an unknown cell-type. These findings indicate that ONO-1078 suppresses the production of IL-4 (a cytokine that affects IgG antibody production), IL-5, and GM-CSF (cytokines that affect eosinophil activation) by peripheral blood mononuclear cells under stimulation with specific antigens in patients with bronchial asthma. Because of its anti-inflammatory effects, ONO-1078 should be useful in the treatment of bronchial asthma.

Adult↗
PubMed1999

A shear-induced in vitro platelet function test can assess clinically relevant anti-thrombotic effects.

Morphological features of haemostatic plugs formed in vitro under high shear forces were investigated. Electron microscopy confirmed the relevance of such haemostatic plug to a platelet-rich arterial thrombus, which is formed in vivo . In rat blood samples, the effects of anticoagulants and various antiplatelet agents on platelet reactivity (rate of haemostatic plug formation) and subsequent coagulation of the flowing blood were investigated. Haemostasis did not occur in citrated blood, and heparin greatly inhibited the shear-induced platelet reaction. Aspirin (1 mM), a thromboxane A(2) receptor antagonist (5 microM), a stable prostacyclin (0.55 nM), a stable prostaglandin E(1) (141 nM) and a phosphodiesterase inhibitor (100 microM) were tested. All these agents exerted significant inhibitory effect on shear-induced platelet reaction, including the inhibition of the very first phase of platelet plug formation, due to aggregation of shear-activated platelets. Except for the phosphodiesterase inhibitor, which prolonged clotting time, none of the above agents affected dynamic coagulation. These results suggest that the employed in vitro shear-induced thrombosis/haemostasis test can reveal in vivo the antithrombotic effect of various agents independently of their mechanism of action.

Journal Article↗
PubMed1999

Giant cell (temporal) arteritis involving both external and internal carotid arteries.

A 76-year-old woman with giant cell (temporal) arteritis was described; she presented with a one year history of headache and tinnitus. Histopathological findings from a superficial temporal artery showed arteritis with granulomatous changes. Bilateral carotid arteriograms demonstrated the stenoses of both internal carotid arteries as well as the narrowing of the superficial temporal arteries. Although we dermatologists rarely encounter the disease in daily clinical practice, it is of clinical importance to perform cerebral angiography in patients suspected of temporal arteritis.

Aged↗
PubMed1999

Norepinephrine, but not epinephrine, enhances platelet reactivity and coagulation after exercise in humans.

The effects of exercise and catecholamines on platelet reactivity or coagulation and fibrinolysis appear to be inconsistent. This may be partly due to the methods employed in previous studies. In the present study, we investigated the effects of acute aerobic exercise and catecholamines on the thrombotic status by a novel in vitro method, shear-induced hemostatic plug formation (hemostatometry), using nonanticoagulated (native) blood. Aerobic exercise (60% maximal O2 consumption) was performed by healthy male volunteers for 20 min, and the effect on platelet reactivity and coagulation was assessed by performing hemostatometry before and immediately after exercise. Exercise significantly increased shear-induced platelet reactivity, coagulation, and catecholamine levels. The effect of catecholamines on platelet reactivity and coagulation was assessed in vitro by adding catecholamines to blood collected in the resting state. The main findings of the present study are that elevation of circulating norepinephrine at levels that are attained during exercise causes platelet hyperreactivity and a platelet-mediated enhanced coagulation. This may be a mechanism of an association of aerobic exercise with thrombotic risk.

Adult↗
PubMed1999

Immunohistochemical analysis of Bcl-2, Bax, Bcl-X, and Mcl-1 expression in pancreatic cancers.

Expression of several members of the Bcl-2 family proteins was investigated by means of both immunohistochemical analysis in 30 invasive ductal adenocarcinomas and 23 intraductal papillary-mucinous tumors (IPMTs) and immunoblot analysis in 6 cancer tissues and 7 pancreatic cancer cell lines. We found that Bcl-2 was expressed in 23%, Bax in 53%, Bcl-X in 90%, and Mcl-1 in 90% of the invasive ductal adenocarcinomas. In intraductal papillary-mucinous adenocarcinomas, the expression rate of Bax was 44% and those of Bcl-XL and Mcl-1 were 88%; these values were higher than those for intraductal papillary-mucinous adenomas. Immunoblot analysis identified Bcl-XL as the predominant form of the Bcl-X protein in both pancreatic cancer tissues and cell lines, and demonstrated that both Bcl-XL and Mcl-1 protein levels were uniformly high in all cell lines. These results suggest that an imbalance between antiapoptosis proteins (such as Bcl-2, Bcl-XL, and Mcl-1) and proapoptotic proteins (such as Bax and Bcl-Xs) is involved in the distinctive biologic features of adenocarcinomas of the pancreas. Furthermore, predominantly high expressions of Bcl-XL and Mcl-1 in intraductal papillary-mucinous adenocarcinomas might be involved in the carcinogenesis in IPMT of the pancreas.

Adenocarcinoma↗
PubMed1999

Adhesion to fibronectin regulates expression of intercellular adhesion molecule-1 on eosinophilic cells.

BACKGROUND: Adhesion molecules may play an important role in eosinophilic activation as well as adherence of extracellular matrix (ECM) including fibronectin (FN) in the inflamed focus. Tissue eosinophils expressed inter-cellular adhesion molecule-1 (ICAM-1, CD54), whereas peripheral blood eosinophils did not. The molecular mechanisms of ICAM-1 expression on eosinophils are not clear. We immunologically examined the effect of adherence to FN on the expression of adhesion molecules in an eosinophilic cell line (EoL-1). METHODS: EoL-1 cells, suspended at a concentration of 2 x 10(6) cells/ml, were cultured at 37 degrees C in BSA or FN-coated 24-well plates. After 4 h, the cells were removed by pipetting, and the expression of adhesion molecules was evaluated by immunofluorescence. RESULTS: Adherence of EoL-1 to FN enhanced ICAM-1 (CD54) expression on EoL-1 (FN vs. BSA: 84.76 +/- 17.90 vs. 43.73 +/- 7.60, mean fluorescent intensity). Regarding other adhesion molecules on EoL-1 (CD11a, CD18, CD49d), the expression was not significantly augmented by adherence to FN. CONCLUSIONS: We concluded that the signal via adhesion of FN regulates the expression of ICAM-1 on eosinophilic cells. This study suggests that eosinophilic adhesion to ECM via adhesion molecules plays an important role in the pathogenesis of allergic inflammation through eosinophilic functional changes, including regulation of expressive adhesion molecules such as ICAM-1.

Cell Adhesion↗
PubMed1999

Synthesis and structure-activity relationship of a new series of potent angiotensin II receptor antagonists: pyrazolo[1,5-a]pyrimidine derivatives.

We have already reported 7-oxo-4,7-dihydropyrazolo[1,5-a]pyrimidine-3-carboxylic acid derivatives, which are potent in vitro angiotensin II (AII) antagonists, but have no oral antihypertensive activity. Removal of the carboxylic acid and replacement of the heteroaromatic system afforded potent in vitro antagonists. Removal of the carbonyl oxygen and changing the position of the biphenyltetrazole substituent were critical to the display of oral activity. To improve the in vitro and oral activities, modifications were made of the substituents at the 3- and 5-positions of the pyrazolo[1,5-a]pyrimidine. Structure-activity studies showed the methyl substituent at the 3-position to be essential for potent in vivo activity. We present the design, syntheses, and biological data of a series of pyrazolo[1,5-a]pyrimidine derivatives, which are orally active AII receptor antagonists.

Angiotensin II↗
PubMed1999

Effects of saiboku-to on the survival of human eosinophils.

In recent years, bronchial asthma has come to be regarded as a chronic inflammatory disease of the respiratory tract, with mast cells, lymphocytes and eosinophils playing important roles in its pathogenesis. Proteins contained in eosinophil granules, especially major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN) and eosinophil peroxidase (EPO), can cause tissue injury. When stimulated, eosinophils release mediators such as leukotriene C4 (LTC4) and platelet activating factors (PAF). Thus, they are recognized as effector cells that are actively involved in the development of allergic inflammation. In this study, eosinophils from healthy volunteers were used to investigate the effects of Saiboku-to on eosinophils whose survival had been prolonged through stimulation with eosinophil-activating cytokines such as interleukin (IL)-3, IL-5 and granulocyte macrophage colony stimulating factors (GM-CSF). As a result, the cytokine-enhanced survival of eosinophils was significantly shortened by the addition of Saiboku-to. These findings suggest that Saiboku-to has the potential to inhibit allergic responses by directly affecting eosinophils which are related to allergic inflammation.

Cell Survival↗
PubMed1999

Effect of anti-ICAM-1 on bronchial response: bronchoalveolar lavage fluid (BALF) and ultrastructural changes of bronchial epithelium in guinea pigs with dual phase bronchial response.

Eosinophils play an important role in the development of bronchial asthma, and the association between ICAM-1 and activation and migration of local eosinophils is attracting attention. Using an asthmatic model of dual phase bronchial response, the effects of anti-ICAM-1 antibody on the airway resistance, cell composition in the bronchoalveolar lavage fluid (BALF) and ultrastructure of bronchial ciliated epithelium were examined under the provoked response by inhalation of the antigen. By administration of anti-ICAM-1 antibody, the late asthmatic response (LAR) was suppressed. In the examination of bronchoalveolar lavage fluid, a significant decrease in eosinophils was found in LAR. In examining transmission and scanning electron microscopies, no difference was found in the immediate asthmatic response, but marked suppression of deciduation of bronchial ciliated epithelium was observed in LAR. These results indicated that anti-ICAM-1 antibody suppressed bronchial asthmatic attack, mainly in LAR, by controlling differentiation and migration of eosinophils.

Administration, Inhalation↗