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Biomedical subjects

Y Kitajima

Publications and source records attributed to Y Kitajima.

At least 109 records · Page 6Linked to original sources
PubMed1996

Design of a Holographically Recorded Plane Grating with a Varied Line Spacing for a Soft X-ray Grazing-Incidence Monochromator.

A new design concept is presented for a plane grating with a varied line spacing for the Monk-Gillieson mounting monochromator. A light path function including both a spherical mirror and a varied-line-spacing grating is defined to optimize groove parameters. Aspheric wavefront recording optics are utilized to fabricate a grating holographically. Ray-tracing results show that the varied-line-spacing grating eliminates aberrations significantly and affords a high resolving power as a total optical system of a soft X-ray grazing-incidence monochromator. The effects of errors in recording parameters and in the radius of the spherical mirror are described, and possible ways to compensate for these errors are discussed.

Journal Article↗
PubMed1996

Human calcitonin has the same inhibitory effect on osteoclastic bone resorption by human giant cell tumor cells as salmon calcitonin.

Human calcitonin (hCT) has been reported to have a less hypocalcemizing effect on rats and to have a lower binding affinity for the receptor of mouse osteoclasts than salmon CT(sCT). In this study we comparatively examined the effect of hCT and sCT on osteoclastic bone-resorbing activity of unfractionated cells obtained from human giant cell tumor of bone and from rabbit and mouse long bones. We found that hCT had the same inhibitory effect as sCT on the bone-resorbing activity of human and rabbit osteoclastic cells, but a different one on that of mouse cells. These results indicate that the activity of drugs should be assayed using human cells if possible.

Animals↗
PubMed1996

Pigmentation abnormalities in systemic scleroderma examined by using a colorimeter (Choromo Meter CR-200).

Cutaneous colors of the dorsum of the hands (A), the distal forearms (B; 5 cm from the wrists), the proximal forearm (C; proximal 1/3 from the elbow) and sternal skin region (D) in patients with systemic scleroderma (73 cases; M:F = 16:57) systemic lupus erythematosus (SLE) or dermatomyositis (27 cases; M:F = 7:20) and healthy controls (HC) (36 cases; M:F = 8:28) was characterized by a XYZ colorimetric system (CIE, 1931) using a colorimeter (Choromo Meter CR-200, Minolta Camera Co. Ltd., Osaka). The index Y, which means color value shows a lower value in male HC and in patients with systemic scleroderma, especially in the more severe type with hyperpigmentation (score 5-6; the system proposed by Ishikawa) than that of female HC. The values of indices x and y, which relate to reddish (erythema with hyperpigmentation) and greenish color (pale), respectively, were higher in the exposed portion of the severe type of systemic scleroderma with hyperpigmentation, especially male and older patients, and in unexposed portions of the female group without hyperpigmentation. Histopathologically, there was prominent pigmentation in the upper dermis of the forearm in the severe type of systemic scleroderma, so that melanin quantity may be closely related to the decrease in index Y. There was no statistical significance in the value of indices Y, x and y between HC, SLE and dermatomyositis. This method may contribute not only to diagnosis of systemic scleroderma and differentiation from other collagen diseases, but also studies of clinical follow-up and effects of medication.

Adult↗
PubMed1996

Different effects of azole-antifungal agents on the regulation of intracellular calcium concentration of Trichophyton rubrum.

Prior studies have indicated that intracellular calcium concentration ([Ca2+]i) is involved in fungal cell growth. However, it has not been known whether antifungal drugs affect signal transduction via calcium in fungal cells. In this context, we examined the effects of antifungal drugs, itraconazole, bifonazole and ketoconazole, on [Ca2+]i in Trichophyton rubrum. Itraconazole (1-5 ng/ml) induced a rapid and transient [Ca2+]i increase, peaking at 15-20s in hyphal cells of T. rubrum, but not in spores. The slow descending phase of the [Ca2+]i increase induced by itraconazole was depleted by chelating extracellular calcium with ethylene glycol bis (beta-aminoethyl ether)-N, N,N',N'-tetraacetic acid (EGTA), suggesting that the increase in [Ca2+]i is biphasic: Ca2+ mobilization from the internal pool and influx from the outside of the cell. At 10 ng/ml and 100 ng/ml, however, itraconazole induced an explosive and sustained calcium increase in both spores and hyphae. At less than 1 ng/ml, no [Ca2+]i increase was caused in both hyphae and spores. On the other hand, although some hyphal cells showed a transient [Ca2+]i increase, most of the cells did not show any changes of [Ca2+]i after the addition of ketoconazole at 10 ng/ml. Both spores and hyphal cells incubated with 100 ng/ml of bifonazole or ketoconazole showed a gradual increase of intracellular calcium concentration until 5 min, when the measurement was ceased. These findings suggest that signal transduction via calcium might be involved in some biological effects of itraconazole on T. rubrum, and that bifonazole and ketoconazole could differently affect [Ca2+]i in T. rubrum from itraconazole. In addition, the determination of [Ca2+]i changes induced by antifungal agents may contribute to clarification of the biological effects on fungal membranes.

Antifungal Agents↗
PubMed1996

Circadian variations of plasma levels of blood coagulation/fibrinolysis molecular markers in progressive systemic sclerosis (PSS).

We measured plasma levels of the blood coagulation/fibrinolysis molecular markers, thrombin-antithrombin III complex (TAT), fibrinopeptide A (FPA), alpha 2-plasmin inhibitor plasmin complex (PIC), beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), at 6:00, 12:00, 18:00 and 24:00 in 10 female patients with progressive systemic sclerosis (PSS) (severe and mild sclerosis groups, each n = 5), 3 cases of dermatomyositis (DM) (M:F = 2:1) and 5 female healthy controls (HC). Corticosteroid (predonisolon; 20-25 mg/day) was administered orally in six patients with PSS and dermatomyositis longer than one month. Plasma levels of TAT increased more than 3 ng/ml in 8 out of 10 cases (80%) of PSS, while the levels increased in only 2 of 8 cases (25%) of the non-PSS groups (DM and HC). The severe sclerosis group of PSS showed a peak at 6:00 in the circadian variations of plasma levels of TAT and FPA, while the mild sclerosis group of PSS showed a peak at 12:00 or 24:00, and both DM and HC at 24:00. However, there was no significant peak in circadian variations of the plasma levels of PIC in the severe sclerosis group of PSS, although there was a peak at 24:00 in other diseases. The synchronized peaks of TAT and PIC were seen in 4 of 8 cases (50%) of the non-PSS group. On the other hand, this synchronization was only detected in 1 of 10 cases (10%) of PSS. The plasma levels of beta-TG and PF4 increased in 8 of 10 cases (80%) of PSS, but these levels did not increase in 8 non-PSS cases. Circadian variation of plasma levels of beta-TG showed a peak at 6:00 in the severe sclerosis group of PSS, while the mild sclerosis group of PSS, DM and HC revealed peaks at different times of 18:00, 24:00 and 12:00, respectively. Additionally, the plasma levels of beta-TG increased more than those of PF4 in the treated group with corticosteroid, although both beta-TG and PF4 revealed a statistically significant correlation in the non-treated group. These results may suggest abnormalities of not only platelet activity, but also of blood coagulation/fibrinolysis system in both severe and mild sclerosis groups of PSS.

Adult↗
PubMed1996

Detection of scleroderma with capillaroscopic abnormalities of nailfolds.

BACKGROUND: Systemic scleroderma is a problem in Gifu Prefecture, Japan. METHODS: Three hundred and thirty-two men and 731 women over 30 years of age, who attended the residents' health examination in K town of Gifu Prefecture (population 4835 persons over 30 years of age) had a dermatologic examination. Antinuclear antibody was determined in 85 persons (14 men, 71 women; age 30 to 72 years) who had Raynaud's phenomenon or various clinical features related to systemic scleroderma. Of these 85 persons, 19 agreed to a capillaroscopic examination and of these, 16 showed some capillaroscopic abnormalities. Biopsy specimens of three women among these 16 individuals with capillaroscopic abnormalities were examined also histopathologically. RESULTS: All samples taken from the forearm skins showed thick and packed bundles of collagen with hyalinization and thickened small blood vessels in the dermis, similar to histopathologic features of systemic scleroderma, although all these women had only a sausage-like swelling of the fingers and a shortened frenulum of the tongue. These results suggest that the prevalence of systemic scleroderma can be estimated to affect more than 0.38% of the population in this town. CONCLUSIONS: Manual skills and vibration exposure may be associated with systemic scleroderma.

Adult↗
PubMed1995

Purification and characterization of lysophospholipase-transacylase (h-LPTA) from a highly virulent strain of Candida albicans.

A lysophospholipase-transacylase (h-LPTA) was purified to homogeneity from a clinical isolate of Candida albicans (C. albicans) that had high extracellular phospholipase activity (strain 16240). The purified enzyme was a glycoprotein with molecular mass of 84 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The specific activities of the enzyme were 117 mumol/min per mg protein for fatty acid release and 459 mumol/min per mg protein for phosphatidylcholine (PC) formation. An apparent Km of the hydrolase activity of the enzyme for 1-palmitoyl-sn-glycero-3-phosphocholine (1-palmitoyl-lyso-PC) was 60.6 microM. The enzyme had a pH optimum at 6.0. Transacylase activity of the enzyme was partially inhibited by palmitoylcarnitine (35% inhibition) and N-ethylmaleimide. In contrast, the hydrolase activity of the enzyme was stimulated by palmitoylcarnitine but was partially inhibited by N-ethylmaleimide. The enzyme exhibited broad specificity to lyso-phospholipids. The h-LPTA activity was not dependent on divalent cations (Ca2+ and Mg2+) and was not inhibited by addition of EDTA or EGTA. These results show that C. albicans strain 16240 with high extracellular phospholipase activity produced h-LPTA in large amount. This enzyme is biochemically distinct from the LPTA enzyme previously isolated from C. albicans 3125.

Acyltransferases↗
PubMed1995

Regulation of translocation of the desmoyokin/AHNAK protein to the plasma membrane in keratinocytes by protein kinase C.

Desmoyokin was identified as a desmosomal plaque protein. We previously demonstrated that desmoyokin is identical to a protein encoded by a human gene, AHNAK, whose expression is suppressed in neuroblastoma cells. Although this protein is distributed in the cytoplasm and the nucleus in various cells, it is associated closely with the plasma membrane in keratinocytes. In keratinocytes, desmoplakin translocates from the cytoplasm to the plasma membrane following both high calcium switch and protein kinase C (PKC) activation by 12-O-tetradecanoylphorbol-13-acetate (TPA). In the low calcium medium, the desmoyokin/AHNAK protein resides diffusely in the cytoplasm and the nucleus. However, 2 h after shift to the high calcium medium, the desmoyokin/AHNAK protein localized to the cell boundary in all cells in a pattern similar to that of desmoplakin. Selective PKC inhibitors completely inhibited the calcium-induced translocation of the desmoyokin/AHNAK protein, but the inhibition of desmoplakin translocation by these inhibitors was only partial. TPA also induced translocation of both the desmoyokin/AHNAK protein and desmoplakin, which was completely inhibited by PKC inhibitors. The calcium-induced phosphorylation of the desmoyokin/AHNAK protein was confirmed by immunoprecipitation using [32P]orthophosphate-labeled keratinocytes. Furthermore, the study of extractability with non-ionic detergent indicated that desmoplakin, but not the desmoyokin/AHNAK protein, is associated with the cytoskeleton. These results suggested an involvement of PKC in the translocation of the desmoyokin/AHNAK protein in keratinocytes. It was, however, also suggested that different mechanisms are likely involved in the translocation of the desmoyokin/AHNAK protein and desmoplakin.

Animals↗
PubMed1995

Involvement of protein kinase C in bradykinin-induced intracellular calcium increase in primary cultured human keratinocytes.

Bradykinin (BK) is one of the key mediators of inflammation and a weak mitogen. We have previously demonstrated that BK induced the generation of inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) which caused Ca2+ mobilization in human keratinocytes. In this study, BK-induced Ca2+ responses were examined in primary cultured human keratinocytes by video imaging fluorescence microscopy using fura-2. Intracellular calcium concentration ([Ca2+]i) level increased to a peak within 30 s after BK addition and decreased gradually to the basal level. The existence of the broad shoulder in the [Ca2+]i profile was suggested to be due to the Ca2+ influx from the external medium, because this disappeared in the presence of 0.5 mM EGTA. Pretreatment with phorbol-12-myristate-13-acetate (PMA), a protein kinase C (PKC) activator, significantly resulted in reduction of the descending shoulder of BK-induced increase in [Ca2+]i. A 20-min pretreatment with PKC inhibitors, H-7 or staurosporine, reversed the decrease by PMA in the shoulder of BK-induced Ca2+ response. Furthermore, the BK-induced [45Ca] uptake was inhibited by EGTA and PMA. Ins(1,4,5)P3 generation induced by BK peaked at 20 s and returned to the basal level at 60 s. There were no significant differences in Ins(1,4,5)P3 levels at 20 and 60 s among the cells exposed to BK alone, BK with PMA pretreatment (20 min) and BK with PMA+H-7 pretreatment. These results suggest that the BK-induced Ca2+ influx, which was shown as shoulder, may be negatively modulated by PKC in primary cultured human keratinocytes.

Adult↗
PubMed1995

Decreased integrin alpha 2, but normal response to TGF-beta in scleroderma fibroblasts.

The distribution and amount of integrin alpha2 were studied in cultured fibroblasts from normal subjects and scleroderma patients by immunofluorescence and immunoblotting using a monoclonal antibody against the human integrin alpha2 subunit. Integrin alpha2 was concentrated at the perinuclear regions in a dot-like pattern in normal fibroblasts on the glass coverslips until the 14th day after planting, and the staining pattern of integrin alpha2 was gradually changed to a dispersed dot-like pattern by the 19th day as examined by immunofluorescence microscopy by using the anti-integrin alpha2 antibody. No difference was observed in the distribution patterns between normal and scleroderma fibroblasts. By immunoblotting study, the amount of integrin alpha2 in scleroderma fibroblasts (n = 10) was less than that of normal fibroblasts (n = 10) (P < 0.01) in both cytosol and cytoskeleton-associated fractions. Furthermore, transforming growth factor beta (TGF-beta) increased the amount of integrin alpha2 in both normal fibroblasts and scleroderma cells by 33%. The total amount of integrin alpha2 in TGF-beta-stimulated scleroderma fibroblasts was less than that in TGF-beta-stimulated normal fibroblasts. These findings suggest that the amount of integrin alpha2, a collagen receptor, is reduced in scleroderma fibroblasts, but the integrin alpha2 production by TGF-beta stimulation is not impaired in scleroderma fibroblasts.

Adult↗
PubMed1995

Histopathological and capillaroscopical features of the cuticles and bleeding clots in ring or middle fingers of systemic scleroderma patients.

Sixty-three patients with systemic scleroderma (SSc) (Barnett I, 41; Barnett II, 17; Barnett III, 5), 14 with systemic lupus erythematosus (SLE), 9 with dermatomyositis (DM) and 10 healthy controls (HC) were subjected to histopathological examinations of the cuticles of ring or middle fingers. The sex ratios (male/female) in the patients with SSc, SLE, DM and HC were 7:56, 5:9, 5:4 and 5:5, and the ages were 22-74, 19-78, 45-70 and 13-78 years old, respectively. Biopsy samples were taken from the central portion of the cuticles, which showed the most severe change of elongation with or without bleeding clots of cuticle-proximal nailfolds (BC). Histopathologically, 61 (96.8%) cuticles of SSc patients consisted of the upper (U), middle (M) and lower (L) layers, which represent obliquely stacked, parabolic, and parallel stacked layers, respectively. The middle parabolic layer appeared to discharge homogenous eosinophilic globular deposits (ED). On the other hand, this typical three-layer-nail pattern was seen only in 9 (64.3%) of SLE, 3 (33.3%) of DM and none of HC, in total 12 (36.4%) of the non-SSc group, which included SLE, DM and HC. In SSc, there were statistical correlations (R2) between ED and BC, ED and cuticle-elongation, cuticle-layer and cuticle-elongation, ED and cuticle-layer, BC and cuticle-elongation. Capillaroscopically, bleeding clots located in the middle layer with ED of the cuticles in eight patients with SSc were transported rapidly within 1-2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Pharmacologic evidence for involvement of phospholipase C in pemphigus IgG-induced inositol 1,4,5-trisphosphate generation, intracellular calcium increase, and plasminogen activator secretion in DJM-1 cells, a squamous cell carcinoma line.

The precise mechanism for acantholysis after pemphigus IgG binds to the cell surface is as yet unknown, although involvement of proteinases such as plasminogen activator (PA) has been suggested. We previously reported that pemphigus IgG, but not normal nor bullous pemphigoid IgGs, caused a transient increase in intracellular calcium ([Ca++]i) and inositol 1,4,5-trisphosphate (IP3) concentration in cultured DJM-1 cells (a squamous cell carcinoma line). To clarify whether phospholipase C is involved in this process after the antibody binds to the cell surface, we examined the effects of a specific phospholipase C inhibitor (U73122) on the pemphigus IgG-induced increase in [Ca++]i, IP3, PA secretion, and cell-cell detachment in DJM-1 cells. [Ca+2]i and IP3 contents were determined with or without 30-min pre-incubation with U73122 or an inactive analogue (U73343) with fura-2 acetoxymethylester and a specific IP3 binding protein, respectively. PA activity in the culture medium was measured after various incubation periods with pemphigus IgG by two-step amidolytic assay. The detachment of cell-cell contacts was examined by detecting the retraction of keratin filament bundle from cell-cell contact points to the perinuclear region by immunofluorescence microscopy using anti-keratin antibody. Pemphigus IgG immediately increased [Ca++]i and IP3 content. PA activity in the culture medium has also been increased at 24 h after pemphigus IgG was added in association with cell-cell detachment. However, pre-incubation with U73122 (1-10 microM), but not with U73343 (10 microM), dramatically reduced the pemphigus IgG-induced increases in [Ca++]i, IP3, and PA activity and inhibited the pemphigus IgG-induced cell-cell detachment. Both U73122 and U73343 caused no effects on cell viability and IgG binding to the cell surface. These results suggest that phospholipase C plays an important role in transmembrane signaling leading to cell-cell detachment exerted by pemphigus IgG binding to the cell surface.

Calcium↗
PubMed1995

Pemphigus IgG, but not bullous pemphigoid IgG, causes a transient increase in intracellular calcium and inositol 1,4,5-triphosphate in DJM-1 cells, a squamous cell carcinoma line.

It is still unclear what kinds of mechanisms are involved in blister formation after antibodies bind to the antigens in pemphigus and bullous pemphigoid. The effects of IgGs from pemphigus vulgaris, pemphigus foliaceus, and bullous pemphigoid sera on intracellular calcium concentration ([Ca++]i) and inositol 1,4,5-trisphosphate were examined in a human squamous cell carcinoma cell line (DJM-1 cells) and in cultured human keratinocytes to clarify whether signal transduction via calcium is involved. IgGs were purified with protein A affinity column from the sera of five pemphigus vulgaris patients, three pemphigus foliaceus patients, eight bullous pemphigoid patients, and 14 normal volunteers. Keratinocytes were cultured in Eagle's minimum essential medium containing 1.8 mM Ca++ and loaded with fura-2/AM, followed by addition of the IgGs. Subsequently, [Ca++]i was determined by measuring the fluorescence ratio (F340/F360) with videomicroscopy. Pemphigus IgGs (seven of eight cases) induced a rapid and transient increase in [Ca++]i in both the cells, whereas a [Ca++]i increase was caused by very few IgGs from bullous pemphigoid (one of eight cases) and normal sera (two of 14 cases). The pemphigus IgG-induced transient [Ca++]i increase was not affected by chelating extracellular Ca++ with ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetracetic acid. In addition, monoclonal antibodies acid. In addition, monoclonal antibodies against 180-kD and 230-kD antigens did not exert this change. Pemphigus IgGs that caused a [Ca++]i increase induced rapid and transient production of inositol 1,4,5-trisphosphate, peaking at 20 seconds. These findings suggest that IgG from pemphigus induces Ca++ mobilization by inositol 1,4,5-trisphosphate from internal stores, and that mechanisms of antibody-transmitted signaling in pemphigus may differ from those in bullous pemphigoid.

Adult↗
PubMed1995

A case of AIDS manifesting pruritic papular eruptions and psoriasiform lesions: an immunohistochemical study of the lesional dermal infiltrates.

A 63-year-old man was referred to our department on September 14, 1992, because of multiple red papules with severe itching. Pruritic papular eruption (PPE) in a human immunodeficiency virus (HIV)-infected patient was diagnosed based on the histological findings, the reduction in CD4, and positive results for HIV antibody. In September of 1993, papules and erythematous plaques with scales appeared on both the palms and soles. The erythema was pruritic and spread gradually to the extremities and trunk. These plaques with erythema and scales are similar to those of the psoriatic lesions seen in Reiter's syndrome, although the HLA typing was not B27. Immunohistopathological findings of the papules of PPE and plaques of psoriasiform lesions showed that perivascularly infiltrated cells in the dermis were mostly lymphocytes. The lymphocytes in PPE were positive for CD45 and negative for CD3, CD43, and CD45RO, but the lymphocytes in psoriasiform lesions were positive for CD45, CD3, and CD43. Moreover, 20-30% of these lymphocytes were also intensely positive for CD45RO. These observations were similar to those obtained in the lesional skin of HIV-negative psoriasis, suggesting that there were no significant immunohistopathological differences in the abnormality of local cellular immunity related to the formation of psoriasiform lesions in HIV-negative psoriasis and HIV-positive psoriasis.

Acquired Immunodeficiency Syndrome↗
PubMed1995

The relationships of onset and exacerbation of pustulosis palmaris et plantaris to smoking and focal infections.

Clinical data, including focal infection and habitual cigarette smoking, were obtained from 203 male patients with pustulosis palmaris et plantaris (PPP) (age: 43.3 +/- 13.4) and 266 female patients (age: 44.0 +/- 13.7) for the 20 years from 1975 through 1994 to evaluate the relationship between the onset or severity of PPP and smoking. Seasonal incidences of onset were also studied. The incidence of onset of PPP symptoms was highest in June, when it is the most humid in Japan, and lowest in December. The most common infectious disease associated with PPP was tonsillitis. The percentages of heavy smoking (more than 20 cigarettes per day) were 74.7% and 32.9% for male and female patients, while those in the normal control population in Japan were 37.2% and 9.8% for males and females. These results suggest that heavy smoking, tonsillitis, and seasonal factors such as high humidity and high temperature may be related to the onset and exacerbation of PPP.

Adult↗