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N Uchiyama

Publications and source records attributed to N Uchiyama.

At least 19 recordsLinked to original sources
PubMed2003

An in vitro interethnic comparison of monoamine oxidase activities between Japanese and Caucasian livers using rizatriptan, a serotonin receptor 1B/1D agonist, as a model drug.

AIMS: Monoamine oxidase (MAO) is located in human liver, and catalyses the oxidative deamination step of many xenobiotics. However, whether there exists an interethnic difference in MAO activities has, to our knowledge, not been clarified. We aimed to assess the MAO type A (MAO-A) involvement in the metabolic pathway of rizatriptan (RIZ), an antimigraine 5-hydroxytryptamine (5-HT)1B/1D agonist, and the interethnic difference in MAO activities between Caucasians and Japanese using RIZ as a model drug in in vitro experiments. METHODS: Oxidative deaminase activities were determined with the subcellular fractions of Japanese livers and the microsomal fraction of Caucasian livers using RIZ, 5-HT (MAO-A substrate) and 2-phenylethylamine (PEA) (MAO-B substrate) as substrates. RESULTS: The oxidative deaminase activities of RIZ vs. 5-HT were highly (r = 0.87 and 0.96, P < 0.001) correlated with each other in both the microsomal and mitochondrial fractions of Japanese livers. Subsequent results were obtained from in vitro experiments using liver microsomes based upon these findings. The oxidative deaminase activities of RIZ were inhibited completely by the nanomolar-order concentration of clorgyline and Ro 41-1049 (MAO-A selective inhibitors), but not by that of Ro 16-6491 (MAO-B selective inhibitor). The majority of the mean Michaelis-Menten values for three substrates toward MAO obtained from six Japanese and six Caucasian liver microsomes reached no significant differences between the two ethnic groups. The mean microsomal oxidative deaminase activities assessed in 18 Japanese and 20 Caucasian livers using the three substrates also showed no significant differences between the two ethnic groups. CONCLUSIONS: RIZ is mainly metabolized by MAO-A and the in vitro oxidative deaminase activities mediated via MAO-A and -B do not appear to differ between Japanese and Caucasians.

Asian People↗
PubMed2003

[The efficacy of switch therapy in community-acquired pneumonia in Japan].

To evaluate the efficacy of Switch therapy for community-acquired pneumonia, we conducted a prospective randomized controlled study in thirty-two hospitalized patients. These cases corresponded to Fine's risk classes II to IV. Using a table of random numbers, sixteen patients were assigned to a Switch therapy group, and the other sixteen, to a clinical pathway group. Both groups initially received intravenous antimicrobials. Within the Switch therapy group, when all the patients were afebrile for more than sixteen hours, their intravenous antimicrobials were switched to oral, and the patients were discharged on the following day. For all patients in the clinical pathway group, the critical pathway was defined as an eight-day planned hospitalization, with a time-task matrix formatted for disease treatment, laboratory testing, physical examination, oxygen saturation monitoring, ambulation, diet, patient education and clinical outcome. Switch therapy reduced the period of intravenous antimicrobial administration from 7.6 days to 4.0 days (p < 0.0001). The period required to switch to oral antimicrobials decreased from 8.3 days to 4.8 days (p < 0.0001); hospital stay length, from 9.8 days to 6.5 days (p = 0.0001); and medical resource utilization, from 330, 373 to 227,768 Japanese yen (p = 0.0002). No patient from either group required readmission. In conclusion, Switch therapy was more efficient than management with a clinical pathway for mild to moderate community-acquired pneumonia in hospitalized patients.

Administration, Oral↗
PubMed2002

Plasma endothelin, nitric oxide and atrial natriuretic peptide levels in humans after abdominal angiography.

PURPOSE: To clarify the effect of the contrast medium iopamidol on endothelial function and response of vasoactive peptide, as measured by changes in the levels of plasma endothelin, nitric oxide and atrial natriuretic peptide. MATERIAL AND METHODS: Thirteen patients received iopamidol 300 mg I/ml intra-arterially during routine abdominal angiography. The mean volume of contrast medium administered was 208.1+/-32.5 ml. Endothelin, nitric oxide and atrial natriuretic peptide were measured before and after angiography. RESULTS: Endothelin levels increased significantly (from 1.45+/-0.12 pg/ml to 1.90+/-0.10 pg/ml) after exposure to contrast medium. Nitric oxide levels decreased significantly (from 34.56+/-2.23 micromol/ to 25.43+/-1.83 micromol/l). Atrial natriuretic peptide levels increased significantly (from 11.43+/-1.68 pg/ml to 21.28+/-2.89 pg/ml). CONCLUSION: Exposure to contrast medium in humans is associated with an increase in plasma endothelin levels and a decrease in nitric oxide levels, and atrial natriuretic peptide levels also increase following CM injection.

Abdomen↗
PubMed2001

Prevention of evaporation of small-volume sample solutions for capillary electrophoresis using a mineral-oil overlay.

The suppression of evaporation of water from small volumes of sample solutions or reagents for capillary electrophoresis by the use of a mineral-oil overlay was investigated in affinophoresis applications, in which the affinity constant of a mutant protein of recombinant human galectin-1 to a lactose affinophore, a triply negative charged ion having a lactoside as an affinity ligand, was determined. When an injection was carried out from a minimum of 20 microL of an aqueous solution beneath the oil overlay, no oil contamination inside the capillary was observed, provided the capillary was cleanly cut so that the end was flat, and the polyimide coating had been removed for a distance of about 2 mm from the end. Affinophoresis was carried out using 20 microL of an affinophore solution covered with an oil overlay. The abnormalities in the electropherograms as the result of the evaporation of the water from the solution during storage prior to use in an automatic operation of a capillary electrophoresis instrument were suppressed, with respect to the formation of a base line gap, an increase in the detection time of a marker ion and an increase in the initial current. A solution in a vial could be used repeatedly for a longer period of time when overlaid with mineral oil than in the absence of an overlay. The use of a mineral-oil overlay is a simple but very efficient technique for solving the problem of the evaporation of water from small volumes of aqueous solutions for use in capillary electrophoresis.

Electrophoresis, Capillary↗
PubMed2001

CT during selective arteriography: anatomical assessment of unruptured intracranial aneurysms before endovascular treatment.

Our aim was to investigate the usefulness of helical CT during selective angiography (CT arteriography) in pretreatment assessment of unruptured intracranial aneurysms. We studied 47 unruptured aneurysms in 34 prospectively recruited patients for whom endovascular embolisation was initially considered. As pretreatment assessment, we performed rotational digital subtraction angiography (DSA) followed by CT arteriography. The findings on axial source images (axial images) and reconstructed three-dimensional CT angiography (3D-CTA) of CT arteriography were compared to those of rotational DSA, with particular attention to the neck of the aneurysm and arterial branches adjacent to it. Information provided by CT arteriography was more useful than that of rotational DSA as regards the neck in 25 (53%) of 47 cases and as regards branches in 18 (49%) of 37 aneurysms. On axial images, small arteries such as the anterior choroidal artery were seen in some cases. CT arteriography can provide valuable additional information about unruptured aneurysms, which cannot be obtained by rotational DSA alone. This technique is useful for obtaining anatomical information about aneurysm anatomy and for deciding the therapeutic strategy.

Adult↗
PubMed2001

Improved cerebral perfusion and metabolism after stenting for basilar artery stenosis: technical case report.

OBJECTIVE: Recent advances in stent technology have allowed the introduction of more flexible stents that may be tracked more easily in the intracranial vessels. We present a patient with improved cerebral blood flow and metabolism as assessed by positron emission tomography after stent-assisted angioplasty for symptomatic basilar artery stenosis. CLINICAL PRESENTATION: A 62-year-old man, who had undergone left superficial temporal artery to middle cerebral artery bypass surgery for left internal carotid artery occlusion 10 years previously, presented with dizziness, blurred vision, and memory disturbance. Angiography revealed severe stenosis of the proximal basilar artery. Positron emission tomographic scans revealed decreased cerebral blood flow associated with increased oxygen extraction fraction in the entire brain, particularly in the posterior circulation and the left middle cerebral artery territory. Despite medical treatment, the patient experienced worsening visual disturbance and right-sided motor weakness. INTERVENTION: Ticlopidine and aspirin were used as antiplatelet agents. In addition, we used argatroban, which is a direct thrombin inhibitor, as an anticoagulant during the procedure. Predilation with a coronary artery balloon was performed, followed by placement of a GFX 3- by 8-mm stent (Arterial Vascular Engineering, Santa Rosa, CA), with excellent angiographic results. The patient made a good neurological recovery, and the postoperative positron emission tomographic scan demonstrated increases in both cerebral blood flow and cerebral metabolic rate of oxygen with a normalization of oxygen extraction fraction. CONCLUSION: Stent-assisted angioplasty can provide a favorable clinical course as well as improved cerebral perfusion and metabolism for a patient with basilar artery stenosis. Long-term follow-up data and additional clinical experience are required to assess the durability of this approach.

Brain↗
PubMed2001

Paramedian supracerebellar transtentorial approach for a medial tentorial meningioma with supratentorial extension: technical case report.

OBJECTIVE AND IMPORTANCE: The choice of surgical approach to treat medial tentorial meningiomas is crucial and sometimes difficult to make. Although the subtemporal approach is most commonly used for lesions that extend mostly supratentorially, it risks injury to the vein of Labbé or the veins coursing along the subtemporal surface. To avoid venous injury, a medial tentorial meningioma was removed transtentorially through the infratentorial space via the paramedian supracerebellar transtentorial (PSCTT) approach. CLINICAL PRESENTATION: A 35-year-old right-handed woman presented with a generalized convulsion. Magnetic resonance imaging scans revealed a left medial tentorial meningioma with supratentorial extension at the dominant hemisphere. The main venous drainage route from the ipsilateral temporal lobe was a sphenopetrosal vein. INTERVENTION: An operation was performed with the patient in a sitting position, and the tumor was resected totally via the paramedian supracerebellar transtentorial approach without perioperative complications. CONCLUSION: The paramedian supracerebellar transtentorial approach is useful for supratentorially located medial tentorial meningiomas without retraction of the temporal lobe and without damage to the vein of Labbé or the sphenopetrosal vein.

Adult↗
PubMed2001

[A case of giant cell tumor originating from the rib].

We have experienced a case of giant cell tumor originating from the rib. A 45-year-old male was admitted to our hospital because of a mass in the left chest wall. A tumor shadow was observed in the left side of chest X ray. Chest CT, bone scintigram showed tumor originating from the left 4th rib. The tumor was suspected giant cell tumor of bone by needle biopsy examination. The tumor was completely resected with chest wall surrounding the tumor. The defect of chest wall was reconstructed with Marlex mesh and the Latissimus dorsi muscle flap. The pathological diagnosis was a giant cell tumor of bone. The patient has been well for two years and one month since surgery, with no signs of recurrence.

Bone Neoplasms↗
PubMed2001

[Usefulness of multiphase helical CT in the diagnosis of pituitary microadenoma].

The purpose of this study was to determine the value of multiphase helical CT (MHCT) in the diagnosis of pituitary microadenoma. Twenty-two patients with clinically suspected microadenoma were examined. Coronal pre-contrast CT was initially carried out. Three series of helical scanning using 1-mm collimation, 1-mm/s table speed, and 1-mm interval reconstruction covering the entire pituitary gland were performed with an intravenous injection of contrast medium. Immediately after MHCT, delayed CECT was performed. Twenty microadenomas (3-10 mm, mean: 5.5 mm) were surgically confirmed. MHCT could depict all 20 tumors, while pre-contrast CT and delayed CECT showed 4 and 12 of 20 tumors, respectively. MHCT was useful in the diagnosis of pituitary microadenoma owing to its high spatial resolution and extensive coverage.

Adenoma↗
PubMed2000

Palladium-Catalyzed cross-Benzannulation of Aminoenynes with Diynes. Highly Regioselective Synthesis of Polysubstituted Anilines.

Polysubstituted anilines were prepared by the palladium-catalyzed cross-benzannulation of conjugated aminoenynes 1-4 with diynes 8. The reaction proceeded in a highly regioselective manner under mild conditions, and the anilines were obtained as single regioisomers. Our method complements the well-known precedures for the preparation of polysubstituted anilines which are widely used in organic synthesis.

Journal Article↗
PubMed2000

The activity of fatty acid synthase of epidermal keratinocytes is regulated in the lower stratum spinousum and the stratum basale by local inflammation rather than by circulating hormones.

The epidermal keratinocytes produce and secrete lipids to maintain the water barrier of the epidermis. To clarify the regulation of epidermal lipid synthesis, we investigated the hormonal effect on the activity of fatty acid synthase (FAS) of the keratinocytes, and the expression of FAS in the human skin. In cultured keratinocytes, the FAS activity, assayed by measuring the oxidation of NADPH, was slightly increased by hydrocortisone or testosterone, but not influenced by thyroid hormone, estrogen, progesterone or insulin. In immunohistochemical study of normal human epidermis, FAS was expressed strongly in the stratum granulosum and moderately in the uppermost layer of the stratum spinousum (SS), suggesting that fatty acid synthesis may increase during normal epidermal differentiation. In inflammatory disorders, such as psoriasis, lichen planus, and atopic dermatitis, FAS was also expressed in the lower SS and the stratum basale (SB), resulting in strong staining in the whole layers of the epidermis. Remarkable increase of FAS expression was only observed in the lower SS and the SB. Therefore, the activity of FAS in the epidermis may be regulated in the lower SS and the SB by local inflammation rather than by circulating hormones. In other components of the skin, FAS was strongly expressed not only in adipose tissue and sebaceous glands, which are known as active sites of lipid synthesis, but also in sweat glands, suggesting that the sweat glands can synthesize abundant fatty acids de novo.

Antibodies↗
PubMed2000

Ruptured irregularly shaped aneurysms: pseudoaneurysm formation in a thrombus located at the rupture site.

OBJECT: The authors describe the clinical, radiological, and pathological findings of ruptured cerebral aneurysms with irregular configurations. METHODS: Eight patients with subarachnoid hemorrhage due to ruptured irregularly shaped aneurysms were examined. The preoperative radiological findings in these cases were compared with the pathological and operative findings of endovascular or open surgery. All of the aneurysms exhibited delayed opacification and delayed washout of contrast medium from the irregularly shaped portion of the aneurysm on digital subtraction angiography and/or helical computerized tomography scanning. Endovascular embolization with platinum coils was attempted in the first four patients who underwent treatment. In three of these patients the aneurysm ruptured again during the endovascular procedure. In the fourth patient an intraaneurysm thrombus was observed during the procedure and clipping was performed. In the subsequent four patients, three underwent clipping without complication and one underwent partial aneurysm embolization because of poor general status. A thrombus adjacent to the aneurysm dome was observed in the patients who underwent open surgery. Pathological examination of the operative specimens revealed a pseudoaneurysm-like cavity in the thrombus that was adherent to the aneurysm. CONCLUSIONS: Ruptured irregularly shaped aneurysms may be accompanied by fragile pseudoaneurysm-like cavities located at the rupture point. Because these aneurysms have a high risk of repeated rupture during an endovascular procedure, advancing microinstruments to the weaker portion of the aneurysm should be avoided.

Adult↗
PubMed2000

Altered activity of MDR-reversing agents on KB3-1 cells transfected with Gly(185)-->Val human P-glycoprotein.

P-glycoprotein (P-gp) is a transmembrane glycoprotein that confers multidrug resistance (MDR). It has been demonstrated that the Gly185 residue within the cytoplasmic loop between predicted transmembrane portions 2 and 3 plays an important role in substrate specificity of human P-gp. Derivatives of cyclosporin interact with and reverse the ability of P-gp to act as a drug efflux pump. To determine if the Gly185 residue of human P-gp is also important for the interaction of P-gp with closely related cyclosporin derivatives, we examined the effect of PSC-833 and CsA on P-gp in KB3-1 cells transfected with human wild-type P-gp (GSV-2) or with the mutant P-gp (VSV-1) that habored the Gly185-->Val substitution. While the ability of CsA to sensitize VSV-1 cells to anticancer agents was enhanced, no changes in the potency of PSC-833 against cells transfected with either the wild-type or mutant P-gp were observed. In addition, VSV-1 transfected cells were more sensitive to CsA inhibition of verapamil-stimulated ATPase activity than cells transfected with wild-type P-gp. Furthermore, the intracellular accumulation of CsA was low in GSV-2 P-gp-expressing cells, compared with its accumulation in VSV-1 cells and it was found to be as high as in non-P-gp expressing KB3-1 cells. These results indicated an enhanced sensitivity of Val185-P-gp expressing cells to CsA that correlated with increased intracellular accumulation in these cells. In contrast, no significant difference in the accumulation of PSC-833 was observed among the parental, wild-type or resistant cells. Since PSC-833 was found to be more potent than CsA, these studies provided insight into the effects of the structure of MDR modulators in mediating sensitivity to anticancer drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Determination of montelukast sodium in human plasma by column-switching high-performance liquid chromatography with fluorescence detection.

MK-0476 (montelukast sodium) is a potent and selective cysteinyl leukotriene receptor antagonist that is being investigated in the treatment of asthma. A simple and sensitive method for the determination of MK-0476 in human plasma was developed using column-switching high-performance liquid chromatography (HPLC) with fluorescence detection. A plasma sample was injected directly onto the HPLC system consisting of a pre-column (Capcell pak MF) and an analytical column (Capcell pak C18) which were connected with a six-port switching valve. The column eluate was monitored with a fluorescence detector (excitation at 350 nm; emission at 400 nm). The calibration curve was linear in a concentration range of 1-500 ng ml(-1) for MK-0476 in human plasma. The intra-day coefficients of variation of all concentrations within the range was less than 9.2%, and the intra-day accuracy values were between 97.2 and 114.6%. This method was used to measure the plasma concentration of MK-0476 following oral administration of the drug in humans.

Acetates↗
PubMed1998

High transepidermal water loss induces fatty acid synthesis and cutaneous fatty acid-binding protein expression in rat skin.

Stratum corneum lipids (SCLs) are responsible for the water barrier function (WBF) of the skin in mammals. Recent studies have indicated that epidermal lipid synthesis might be regulated by WBF of stratum corneum and that cutaneous fatty acid-binding protein (C-FABP) plays an important role in fatty acid metabolism in epidermis. To clarify the regulatory mechanism of lipid synthesis, we assessed the effects of barrier disruption induced by either acetone treatment or linoleic acid deficiency on epidermal lipid synthesis in rat. Transepidermal water loss (TEWL) was measured with an evaporimeter before and after treatment. The time course of re-establishing SCLs was examined biochemically and histochemically and the expression of C-FABP in the epidermis was immunohistochemically examined. When the rat skin was covered with a vapor-impermeable membrane after the acetone treatment removing SCLs and inducing WBF disruption, the usual recovery of SCLs was blocked and TEWL was kept high by 24 h. In the uncovered area, rapid redeposition of SCLs within 24 h was found and associated with normal compositions of epidermal lipids including sphingolipids, free fatty acids and sterol and, immunohistochemically, C-FABP was very weakly expressed in epidermis at 0.5 and 2 h, and then strongly in the whole layers at 4 h, and returned to a normal pattern by 8 h. The epidermis of the covered rat skin was kept weak in C-FABP expression by 24 h. In the linoleic acid-deficient rats, TEWL did not increase and the expression pattern of C-FABP showed no notable change until 28 weeks after initiation of the diets, indicating that C-FABP expression may not be affected by altered essential fatty acid metabolism. These results suggest that increase of TEWL itself stimulates C-FABP expression, leading to activation of fatty acid metabolism.

Acetone↗
PubMed1998

Diagnostic value of contrast-enhanced computed tomography for diagnosing the intraductal component of breast cancer.

BACKGROUND: It is important to reduce local residual cancer to avoid local recurrence after breast conserving treatment. We therefore tried to detect the intraductal components and small invasive foci of breast cancers by contrast-enhanced helical computed tomography (CE-CT). METHODS: In 122 women whose breasts were examined by CE-CT preoperatively, intraductal spread detected on ultrasound (US), mammography (MMG), and CE-CT, and extensive intraductal components (EICs) detected by histological examination were analyzed for correlations among the extent and subtypes of intraductal components, and deviations in tumor size. RESULTS: EICs were present in 44 patients. The sensitivities of EIC detection by US, MMG, and CE-CT were 35%, 61%, and 88%, respectively, and the corresponding specificities were 83%, 86%, and 79%, respectively. The sensitivities of detecting EIC and small invasive foci were 34%, 57%, and 91%, respectively. In 5 patients, EIC could only be visualized by CE-CT. The median deviation of the size of intraductal spread revealed by CE-CT from pathological EIC was 0.0 cm (range + 3.0 to - 1.7 cm). CONCLUSIONS: CE-CT is useful for visualizing intraductal spread and small invasive foci of breast cancer.

Adult↗
PubMed1998

CD2-, CD4+, CD56+ agranular natural killer cell lymphoma of the skin.

We present a case of CD56-positive cutaneous lymphoma with a clinical appearance resembling angiosarcoma. The biopsy specimen showed angiocentric infiltrates of small to medium-sized cells positive for CD4, CD45, and CD56 but negative for CD2, surface and cytoplasmic CD3, CD8, CD20, and CD57. There was no detectable clonal rearrangement of either TCRbeta or TCRgamma genes and no dense core granules in the cytoplasm. Epstein-Barr virus was not detected. The patient died of an unrelated disease 20 months after initial biopsy, although there was some response to interleukin-2, radiotherapy, and VP-16. The results suggest that our case does not precisely match the recently proposed variants of CD56-positive lymphoma, namely nasal T/natural killer cell lymphoma and blastic natural killer cell lymphoma. Agranular natural killer cell lymphomas similar to our case in the immunophenotype have been reported to be indolent and occur in the skin. These lymphomas may be a distinct subtype and have a predilection for involving the skin.

Aged↗