Biomedical subjects
Publications and source records attributed to Y Urano.
The membrane-permeating indicator DAF-FM DA is transformed by intracellular esterases into the highly water-soluble dye DAF-FM, which traps NO produced by NO synthase (NOS) to yield a highly fluorescent triazole compound in cells (see schematic diagram). Monitoring with a fluorescence microscope should allow direct identification of intracellular production and location of NO.
The first fluorescent chemical traps for (1)O(2) have been developed. DPAXs react specifically with (1)O(2) to yield the corresponding endoperoxides, DPAX-EPs (see scheme; X = H, Cl, F). DPAXs scarcely fluoresce, while DPAX-EPs are strongly fluorescent. Since the fluorescence of these probes is unaffected by H(2)O(2), superoxide, and nitric oxide, they are useful for the selective detection of (1)O(2) in biological systems.
Microscopic visualization of intracellular enzyme activity can provide information about the physiological role of the enzyme. Caspases are cysteine proteases that have critical roles in the execution of apoptosis. General fluorometric substrates of caspase-3, such as DEVD-MCA, are unsuitable for imaging because they are excited at short wavelength, so we designed and synthesized novel fluorescent probes that are excited at suitable wavelengths for detecting caspase-3 activity in living cells. Using one of these probes, we succeeded in microscopic visualization of caspase-3-like activity within HeLa cells treated with etoposide. The caspase-3-like activity was increased in the cytosol at first, then expanded to the whole cell.
We attempted to identify the effects of aging on the response of vascular smooth muscle cells (VSMCs) to injury. Rat aortas were injured by ballooning, and cell outgrowth of the aortic explants, as well as cell proliferation and apoptosis induced by 7-ketocholesterol in the culture system were compared in young (6-7 weeks) and old (40-50 weeks) rats. Explant outgrowth in uninjured rats did not differ between young and old rats. However, 14 days after balloon injury, the number of explants with outgrowth increased by a factor of four (P<0.01) in young rats, while that of the old rats did not change. Cell proliferation in cultured VSMCs also did not differ between young and old uninjured rats, but, in the injured group, proliferation doubled in young rats (P<0.01), but did not change in the older group. The rate of unadhered cells in the presence of 7-ketocholesterol (30 microM) did not differ between young and old uninjured rats. In the injured rats, however, that of young rats was lower (P<0.01) while that of older rats was higher (P<0.01). The extent of DNA fragmentation (%) after the addition of 7-ketocholesterol (30 microM) did not differ between young and old uninjured rats. In the injured groups, DNA fragmentation was lower in the young rats (P<0.01), and higher in the old ones (P<0.01), when compared to their respective controls. These results indicate that the VSMC injury responses of cell outgrowth and proliferation were more pronounced in the young, and that 7-ketocholesterol-induced apoptosis was more extensive in old rats.
We report a case of acute febrile neutrophilic dermatosis, Sweet's syndrome, associated with chronic myelogenous leukemia (CML) in which we found rearrangement of the bcr gene in DNA obtained from a skin lesion as well as in blood DNA by Southern blot analysis. This indicated the presence of CML cells within the skin lesion. To our knowledge, this is the first report in which the presence of CML cells is shown within skin lesions of Sweet's syndrome. In our patient, leukocyte alkaline phosphatase activities returned to normal levels when he was suffering from Sweet's syndrome and decreased again to below normal levels after it subsided. Whether the normalization of leukocyte alkaline phosphatase activity is common among CML patients with Sweet's syndrome remains to be determined.
The tumor suppressor gene PTEN is deleted and/or mutated in a variety of tumors and the susceptibility gene for Cowden disease. Loss of heterozygosity of chromosome 10q23, where PTEN resides, in squamous cell carcinomas (SCCs) of human skin and the association of SCC with Cowden disease were reported previously. In the present study, we screened for mutations of PTEN in SCCs by polymerase chain reaction single strand conformation polymorphism analysis to examine whether PTEN is involved in the carcinogenesis of SCC. None of 21 SCCs showed somatic mutations in the coding regions of PTEM. Instead the same allelic variation was detected in two cases without any clinical features of Cowden disease. Our results indicate that inactivation of PTEN does not play an important role in the carcinogenesis of SCC.
The use of a cheek rotation flap is a well-known method for reconstruction of a large defect of the lower eyelid. In this technique, a separate lining tissue supporting the cheek flap is required for full-thickness reconstruction. Previously, a chondromucosal graft or conchal cartilage has been used to support this flap. Recently, we have used a homologous or autologous fascia lata as support for the cheek flap instead of rigid tissues like cartilages. A fascia lata strip is fixed with tolerable tension to the medial canthal tendon and lateral orbital rim. The inner surface of the fascia and the cheek flap is lined with a buccal mucosa graft to decrease irritation of the conjunctiva and cornea. We present here seven patients in whom this procedure was used for lower eyelid reconstruction following resection of a malignant skin tumor. Based on follow-ups of 7 to 22 months, the functional and aesthetic results have been good in all cases. This procedure may be applicable for total or subtotal reconstruction of the lower eyelid.
We report here a 7-year-old Japanese girl with cerebriform intradermal nevus (CIN). By placement of expanders on the galea, her scalp was expanded more easily with less discomfort than is expected when the expanders are placed under the galea. An immunohistochemical study on the expression of proliferating cell nuclear antigen suggested higher proliferative activity of nevus cells from the CIN lesion than that of cells from congenital or acquired intradermal nevi. The high proliferative activity appeared to be associated with a growth spurt of the lesion.
Several L-arginine analogs are known as potent inhibitors of nitric oxide synthase (NOS). We recently synthesized dipeptides containing such amino acids, and found that they are potent and isozyme-selective NOS inhibitors. For example, S-methyl-L-isothiocitrullinyl-L-phenylalanine showed 66-fold selectivity for iNOS over nNOS, while S-methyl-L-isothiocitrullinyl-L-leucine and N(G)-nitro-L-argininyl-L-phenylalanine showed 20- and 14-fold selectivity, respectively. Interestingly, S-methyl-L-isothiocitrullinyl-D-phenylalanine showed no selectivity, and S-methyl-L-isothiocitrullinyl-L-phenylalanine showed competitive inhibition. These results suggest that each NOS isozyme has a cavity of different size near the C-terminal of the L-arginine binding site, and that the selectivity of inhibitors is due to the differences in the size of the cavity.
The biological functions of nitric oxide in the neuronal system remain controversial. Using a novel fluorescence indicator, DAF-2 DA, for direct detection of NO, we examined both acute rat brain slices and organotypic culture of brain slices to ascertain NO production sites. The fluorescence intensity in the CA1 region of the hippocampus was augmented, especially after stimulation with NMDA, in acute brain slices. This NO production in the CA1 region was also confirmed in cultured hippocampus. This is the first direct evidence of NO production in the CA1 region. There were also fluorescent cells in the cerebral cortex after stimulation with NMDA. Imaging techniques using DAF-2 DA should be very useful for the clarification of neuronal NO functions.
BACKGROUND: A severe adverse reaction to sulfasalazine therapy has been associated with hypersensitivity syndrome, the clinical features of which are similar to infectious mononucleosis. No serologic evidence of viral infections has been reported with this syndrome; however, human herpesvirus 6 infection has not been specifically investigated, which could cause an infectious mononucleosislike syndrome. OBSERVATIONS: We report 2 cases of hypersensitivity syndrome induced by the use of sulfasalazine. The clinical features of the syndrome appeared 18 and 32 days after administration of sulfasalazine. Clinical signs included a maculopapular rash progressing to exfoliate erythroderma, fever, and lymphadenopathy. Leukocytosis, atypical lymphocytes, liver dysfunction, and renal disturbance were also observed. In 1 patient, human herpesvirus 6 variant B was isolated from peripheral blood mononuclear cells, and in both patients anti-human herpesvirus 6 IgG titers increased considerably. CONCLUSIONS: Two cases of hypersensitivity syndrome due to sulfasalazine use were associated with the reactivation of human herpesvirus 6, which may be a required cause of hypersensitivity syndrome.
A 40-year-old Japanese man with psoriatic arthritis (PA) involving the spine, sacroiliac and peripheral joints presented with dyspnoea and ankle oedema. Blood pressure was 180/110 and 114/80 mmHg in the right and left upper arms, respectively. Examinations showed left ventricular dilatation and diffuse hypokinesis of the left ventricle, with no involvement of the coronary arteries. Aortography detected total occlusion of the left subclavian artery and stenosis of the origin at the right renal artery. Dilated cardiomyopathy and Takayasu's arteritis associated with PA was diagnosed. A few cases of PA have been reported in association with cardiovascular diseases, but the association of these three diseases has not been documented in the literature to date. Dermatologists need to be aware of cardiovascular manifestations in patients with PA, because cardiovascular diseases are not rare in other seronegative spondyloarthropathies.
A 14-year-old Japanese girl had a lifelong history of skin lesions developing after generalized exposure to cold air; the lesions were often accompanied by systemic symptoms such as fever and chills. The skin lesions were non-pruritic, maculopapular, erythematous eruptions and were neither urticarial nor angioedematous. An ice-cube test was negative. Laboratory examinations showed marked leucocytosis during an acute attack. On the basis of clinical features, histological findings and laboratory data, although these symptoms were sporadic, the most likely diagnosis was familial polymorphous cold eruption, which has also been referred to as familial cold urticaria. Serum levels of granulocyte colony-stimulating factor and interleukin 6 were significantly elevated during an acute attack after cold exposure, suggesting that both cytokines played important parts in the development of her condition.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Apert syndrome is a clinically distinctive condition characterized by craniosynostosis, mid-face hypoplasia, and severe symmetrical syndactyly of the hands and feet. Recently, mutations of the fibroblast growth factor receptor 2 (FGFR2) gene have been associated with several craniosynostosis conditions including Apert, Crouzon, Jackson-Weiss, and Pfeiffer syndromes. Mutations detected in Crouzon, Jackson-Weiss, and Pfeiffer syndromes are located at several sites in the FGFR2 gene. However, the mutational spectrum in Apert syndrome is remarkably narrow. Mutations detected thus far in Caucasian patients with this syndrome are exclusively transversions from cytosine to guanine at either nucleotide position 934 (C934G) or 937 (C937G) in the FGFR2 gene. To examine the possibility that the narrow mutational spectrum in Apert syndrome was a result of racial or environmental predilection, we studied three Apert syndrome patients from two unrelated Japanese families for C934G and C937G mutations. The C934G mutation was found in all three patients. This is the first demonstration of FGFR2 gene mutations in Japanese patients. Our evidence that the C934G mutation identified in Caucasian patients also occurs among Japanese patients excludes the possibility of racial or environmental predilection for this mutation. Nucleotide position 934 is a mutational hotspot of the FGFR2 gene in Japanese patients as well, although the mechanism by which the mutation occurs remains to be clarified. Whether C937G is a mutational hotspot in Japanese patients as well remains to be determined.
A specific and sensitive detection method for nitric oxide (NO) in living cells and tissue culture systems is required in the search for novel NO synthase (NOS) inhibitors. We have improved a fluorometric determination with 2,3-diaminonaphthalene (DAN) by the addition of 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO) as an oxidant to form NO2 from NO. This method is 3 times more sensitive than that without PTIO, and is suitable for examining the NOS-inhibitory activity of large numbers of test compounds using a 96-well microplate reader. The improved method was applied to N-monomethyl-L-arginine (L-NMMA) as a known inhibitor and the derivatives of 2-phenyl-1,2-benzisoselenazol-3(2H)-one as teat compounds in order to investigate the effect of these compounds on NO production from activated rat aortic smooth muscle cells. The results obtained indicate that this method is suitable for the rapid assay of large numbers of test compounds.
To investigate the cellular basis of the action of thyroid hormone on hair follicles, we studied the immunohistochemical localization of thyroid hormone receptors (TRs) in human scalp skin using a mouse monoclonal antibody, TR alpha 1 (C4) against TRs. Immunoreactive TRs were detected in the nuclei of the outer root sheath cells (ORSCs), dermal papilla cells (DPCs), fibrous sheath cells of hair follicles, hair arrector pili muscle cells and sebaceous gland cells. However, nuclei of hair matrix cells were not clearly stained with TR alpha 1 (C4). The epidermis showed positive nuclear staining by the antibody. Ductal and secretory portions of eccrine sweat glands were also stained with the antibody as we had expected. In the dermis, almost all the cell components including fibroblasts, vascular endothelial and smooth muscle cells, and Schwann cells were positively stained. Immunofluorescence also showed TRs expression in cultured ORSCs, DPCs, epidermal keratinocytes and dermal fibroblasts. L-triiodothyronine stimulated the proliferation and/or metabolism of all these four types of cells significantly, although there was variation at the rate of stimulation. Whereas, structurally similar, but metabolically inactive analog, reverse T3 had no effect. These results demonstrate the presence of thyroid hormone nuclear receptors in human hair follicles. Furthermore, the presence of TRs in different cell types in the skin suggests numerous direct effects of thyroid hormone on this target tissue.