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Biomedical subjects

M Seishima

Publications and source records attributed to M Seishima.

At least 19 recordsLinked to original sources
PubMed1997

Marked increases in concentrations of apolipoprotein in the cerebrospinal fluid of poliovirus-infected macaques: relations between apolipoprotein concentrations and severity of brain injury.

Apolipoproteins in cerebrospinal fluid (CSF) might have important functional roles in the pathophysiology of brain and lipid metabolism in the vascular component. The present study examined apolipoprotein A-I (apo-A-I) and apolipoprotein E (apo-E) levels in CSF and serum from poliovirus-infected macaques. Poliovirus-infected macaques developed motor deficits and were classified into three groups: (1) muscle weakness in one or both legs; (2) partial paralysis in one or both legs; (3) complete paralysis in one or both legs. No motor deficits were evident in the control or sham-treated macaques. Apo-A-I concentrations in CSF were markedly elevated in poliovirus-infected macaques with weakness, partial or complete paralysis, in comparison with either control or sham-treated animals, and were proportional to the severity of motor impairment. Apo-E concentrations in CSF were also significantly elevated in poliovirus-infected macaques with complete paralysis. The magnitude of increase in CSF apo-A-I or apo-E concentrations was also closely associated with the degree of histologic neurological damage and inflammation (lesion scores). However, no changes in serum apo-A-I and apo-E concentrations were observed in the poliovirus-infected macaques compared with control macaques. Furthermore there were no significant correlations apo-A-I or apo-E concentrations between serum and CSF. We hypothesize that the elevation of apo-A-I and apo-E concentrations after poliovirus infection is caused by immune stimulation within the central nervous system (CNS). Measures of CSF apo-A-I and apo-E levels might serve as a useful marker for the severity and/or the range of CNS injury.

Animals↗
PubMed1996

Expression of activin A in human keratinocytes at early stages of cultivation.

Activins are members of the TGF-beta superfamily and are classified into 3 types: activin A, which consists of a homodimer of betaA, activin B, which consists of a homodimer of betaB, and activin AB, which consists of a heterodimer of betaAbetaB. We studied the expression of activin mRNAs by RT-PCR in normal human epidermis, cultured keratinocytes, and DJM-1 cells (a squamous cell carcinoma line). We could detect only activin A mRNA (betaA) in normal human epidermis. In cultured keratinocytes and DJM-1 cells, activin betaA mRNA was observed at 4 h but not at 96 h after plating. Activin A activity was detected in the conditioned medium of DJM-1 cells within 48 h. In addition, although follistatin mRNA was not observed in human epidermis in situ, it was transiently expressed in cultured cells at 4 h after plating. These findings suggest that the expression of these molecules in keratinocytes is associated with cell proliferation. In an in vitro tissue injury model, activin A was observed at the wound edge, where cell migration and proliferation may be activated. In DJM-1 cells cultured for 92 h, betaA mRNA was observed 4 h after injury treatment. These findings suggest that activin A acts as a potent inducer of proliferation in vitro, at least in keratinocytes.

Activins↗
PubMed1996

Impaired synthesis of retinol-binding protein and transthyretin in rat liver with bile duct obstruction.

To gain further insight into the protein metabolism in bile duct-obstruction, we examined the synthesis of retinol-binding protein (RBP) and transthyretin (TTR) in rats with common bile duct-ligation. In these rats, liver and plasma levels of RBP and TTR decreased markedly, whereas liver retinoid contents remained unchanged. Although there appeared no decrease in the total amount of RBP or TTR mRNA expressed in the liver, the subcellular distribution of these mRNAs changed from the membrane-bound polysome fraction to the membrane-unbound polysome fraction. This abnormal distribution recovered rapidly after biliary drainage, resulting in the subsequent recovery of the plasma RBP and TTR levels. These observations suggest that cholestasis inhibits the synthesis and secretion of RBP and TTR by disrupting the binding of their mRNAs to membrane-bound polysomes. Plasma levels of RBP and TTR might be sensitive indicators of the recovery of protein synthesis after biliary drainage in patients with obstructive biliary disorders.

Animals↗
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

Oral supplementation with branched-chain amino acids improves transthyretin turnover in rats with carbon tetrachloride-induced liver cirrhosis.

The hypothesis that dietary branched-chain amino acid (BCAA) supplementation improves the impaired protein turnover in male Donryu rats with carbon tetrachloride-induced liver cirrhosis was tested. We supplemented cirrhotic rats orally for 2 wk with BCAA solution [26.67 mg BCAA/(100 g body weight . d)], a conventional amino acid mixture [4.25 mg BCAA/(100 g body weight . d)] or saline and fed these three groups the AIN76 basal diet to have similar intakes of total energy and total nitrogen. Normal rats without liver cirrhosis were fed the basal diet similar to the above (noncirrhotic controls). After supplementation, rats were fed intravenous transthyretin (thyroxine-binding prealbumin) doubly labeled with 125I-tyramine-cellobiose and 131I. Kinetic indices including production rate of transthyretin were analyzed from plasma transthyretin disappearance curves. Tissue sites of transthyretin degradation were assayed using a trapped ligand technique by measuring 125I-tyramine-cellobiose levels. The production rate of transthyretin was significantly lower in cirrhotic rats supplemented with saline (mean 25.46 X 10(-3) . h(-1)) compared with noncirrhotic controls (45.08 X 10(-3) . h(-1)) (P < 0.05). This was corrected by supplementing cirrhotic rats with BCAA (37.05 X 10(-3) . h(-1), P < 0.05) but not with conventional amino acid mixture (22.49 X 10(-3) . h(-1)). The accelerated degradation of transthyretin in muscles of cirrhotic rats was improved by BCAA (P < 0.05). In conclusion, dietary supplementation with BCAA improves the impaired transthyretin turnover in rats with liver cirrhosis.

Administration, Oral↗
PubMed1996

Reduction of intestinal apo A-IV mRNA levels in the cirrhotic rat.

In the present study, intestinal apo A-IV synthesis was investigated using a carbon tetrachloride (CCl4)-induced cirrhosis rat model. Triglyceride (TG) content in rat cirrhotic liver was increased markedly by 170% (P < 0.001) and apo B was increased by 20% (P < 0.05) compared with control levels. These results reflected the steatotic change in the liver. In contrast, TG levels in the small intestine of cirrhotic rats decreased significantly (P < 0.01). In addition, intestinal apo A-IV (jejunum P < 0.001; ileum P < 0.01) and its mRNA levels (jejunum P < 0.01; ileum P < 0.05) were also reduced. The decreased apo A-IV content in the jejunum was confirmed by immunohistochemical analysis. These results indicate that intestinal apo A-IV synthesis in cirrhosis is suppressed, at least under the condition of an overnight fast. Therefore, decreased intestinal apo A-IV synthesis may relate to the decreased ability to absorb fat in cirrhosis, but a fat-loading study will be necessary to confirm this hypothesis. It is unknown from the present study why serum apo A-IV level is not significantly decreased, despite a reduction in apo A-IV synthesis. The clearance of apo A-IV by the liver may be delayed or apo A-IV synthesis may be rather markedly enhanced during fat absorption in liver cirrhosis.

Animals↗
PubMed1996

Effects of lipid administration on lymphatic apolipoprotein A-IV and B output and synthesis.

We examined the mesenteric lymphatic and portal venous transport of triglyceride (TG), free fatty acids (FFA), apolipoproteins (apo)A-IV and B in response to a bolus duodenal infusion of a TG-free control solution, and long-chain (18:1) and medium-chain (8:0) TG (LCT and MCT, respectively) emulsions in the rat. Additionally, intestinal and hepatic apo A-IV and apo B mRNA levels were also measured. Lymph apo A-IV, apo B (B-48), FFA, and TG output increased after LCT infusion, whereas only apo A-IV and FFA outputs increased after MCT infusion. On the other hand, portal FFA and apo A-IV transports increased at 15 min after MCT infusion but not after LCT infusion. Portal TG and apo B transports were not altered by either MCT or LCT infusion. Jejunal apo A-IV mRNA was increased after both MCT and LCT infusions. Hepatic apo A-IV mRNA levels increased only after MCT infusion. Conversely, neither LCT nor MCT had any effect on apo B mRNA levels in intestine or liver. These results indicate that apo A-IV is regulated by MCT absorption and that fatty acid reesterification and lipoprotein assembly are not prerequisite for such regulation. Conversely, it is likely that apo B-48 participates only in the formation and/or transport of chylomicrons after LCT absorption.

Animals↗
PubMed1996

[Clinical significance of serum soluble interleukin-2 receptor (sIL-2R) determination in patients with rheumatoid arthritis].

It has been recently shown that soluble interleukin-2 receptor (sIL-2R) is related to the pathogenesis of autoimmune diseases. We determined serum levels of sIL-2R in patients with rheumatoid arthritis (RA). Fifty-three patients (3 males and 50 females from 35 to 70 years old) and sex- and age-matched 50 healthy subjects were included in this study. The sIL-2R concentrations positively correlated with Lansbury index of RA (r = 0.602, p < 0.01). There was a significant correlation between sIL-2R levels and the prevalence of CD3+.HLA-DR+ lymphocytes (r = 0.420, p < 0.01).

Adult↗
PubMed1996

[Subfractionation of serum high density lipoproteins and its clinical significance].

Serum concentrations of HDL subfractions, LpAI and LpAI:AII, were simultaneously determined simply, specifically and rapidly by use of rocket immunoelectrophoresis with the home-made gel plates. The method was reproducible, and the results correlated well with those obtained with Sebia's kits. The normal levels of LpAI were 57 +/- 13 mg/dl in males and 59 +/- 15 mg/dl in females. LpAI levels were significantly lower in patients with renal failure and atherosclerosis, and tended to decrease in hepatic diseases than those in normal subjects. The levels of LpAI:AII were also decreased in these three diseased groups. Decreases in LpAI levels were more slightly in patients with hepatic or renal diseases than those in LpAI:AII levels. On the contrary, decrease in LpAI level was more markedly in patients with atherosclerosis than that in the other subfraction. The results in the present study suggest that the determination of HDL subfractions will be useful for diagnosis of various diseases.

Adult↗
PubMed1996

Highly sensitive ELISA for soluble Fas in serum: increased soluble Fas in the elderly.

We have developed and characterized a highly sensitive ELISA for soluble Fas (sFas) in the serum. The linearity of calibrator range was 0.06-2.00 micrograms/L and the detection limit was 0.01 microgram/L. The average within- and between-run CVs were 3.9% and 3.8%, respectively. The recovery of added sFas to serum was 93-118%. The effects of possible interferences (tryglyceride, hemoglobin, bilirubin) were negligible. We determined serum sFas in 155 healthy subjects, ages 20-69. The mean value of sFas in men (2.50 +/- 0.63 micrograms/L, n = 78) was significantly higher than that in women (2.01 +/- 0.53 micrograms/L, n = 77) (P < 0.001). Furthermore, there was a significant correlation between serum sFas concentration and age (men, r = 0.397, P < 0.001; women, r = 0.569, P < 0.001). Although the concentrations of sFas tended to increase with aging, it remains to be clarified how Fas-mediated apoptosis relates to aging.

Adult↗
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

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

Involvement of phospholipase D in ganglioside GQ1b-induced biphasic diacylglycerol production in human keratinocytes.

Ganglioside IV3 (NeuAc)2, II3 (NeuAc)2-GgOse4Cer (GQ1b), which induces terminal differentiation in keratinocytes, was previously found to enhance the mass content of inositol 1,4,5-trisphosphate and intracellular calcium concentration ([Ca++]i), peaking at 30 seconds. In the present study, the biphasic accumulation of 1,2 diacylglycerol, i.e., the first transient and the second sustained phase, was observed in cultured human keratinocytes stimulated by GQ1b. On the other hand, II3 NeuAc-LacCer (GM3), which inhibits keratinocyte proliferation without inducing differentiation, did not cause diacylglycerol formation. Phosphatidylethanol, produced by transphosphatidylation and a potential marker for phospholipase D activity, was produced by the exposure to GQ1b in the presence of ethanol. The second sustained phase of diacylglycerol was repressed by ethanol, indicating that the diacylglycerol-formation pathway via phospholipase D followed by phosphatidic acid phosphohydrolase would in part account for the second diacylglycerol phase. Furthermore, this second phase of GQ1b-induced diacylglycerol generation was reduced by pretreatment with propranolol, an inhibitor of phosphatidic acid phosphohydrolase. In addition, the levels of [3H]choline, a direct metabolite of the phospholipase D pathway, were elevated within 1 min after GQ1b addition and then sustained for at least 20 min. Taken together, the results suggest that the phospholipase D pathway may contribute to the second phase of diacylglycerol formation, which might be involved in differentiation.

Cell Differentiation↗
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↗