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Y Kitajima

Publications and source records attributed to Y Kitajima.

At least 91 records · Page 5Linked to original sources
PubMed1998

Introduction: electron microscopy for fungal cell ultrastructure

Ultrastructural morphology is a principal study for almost all natural science, i.e., an inevitable and fundamental study to elucidate structures, functions and differentiation of a given tissue, cell, or molecule as a most understandable visual form. The number of young scientists, however, who have been engaged in this field is very small recently, since this field appears to be too old when compared with modern molecular biology and it takes much longer time for the beginner to master the methology for electron microscopy (EM). This symposium is designed for these young scientists and molecular biologists or biochemists, who are not so familiar to ultrastructural morphology, to better understand the applicability of EM, through new results and findings in ultrastructures of fungal cells and related organisms. EM includes several kinds of methods, which are shadowing EM, negative staining EM, ultrathin section EM, scanning EM, freeze-fracture EM, immuno-EM and diverse methods for staining the specimen. Shadowing EM and negative staining EM are suitable methods for the study molecular structures of proteins, and the former is prepared by shadowing with platinum palladium in a vacuum chamber, and the latter is a method to observe a relief prepared by dipping the sample in phosphotungsten solution. Freeze-fracture electron microscopy is suitable for the study of membrane plane ultrastructures, since it reveals a wide planar view of the membrane by splitting it along the hydrophobic membrane internal plane. Immunoelectron microscopy is an essential method for the study of intracellular localization of proteinous molecules. These methods will be introduced. This symposium will introduce new findings as for fungal cells, bacteria and protozoa obtained principally by using electron microscopy. These findings obtained through ultrastructures may provided a renewed knowledge of research approach from view points of ultrastructure.

Journal Article↗
PubMed1998

[Molecular cloning of Candida albicans phospholipase D].

Phospholipase D (PLD) catalyses the hydrolysis of phosphatidylcholine, a major substrate, to phosphatidic acid and choline, and its activity is regulated by a variety of hormones, growth factors, and other extracellular signals in mammalian cells. Thus, it is now recognized as a signal transducing enzyme such as phosphatidylinositol-specific phospholipase C, adenylate cyclase, or protein tyrosine kinases. Furthermore, recent findings that regulation by members of the ADP-ribosylation factor (ARF) and Rho families of monomeric GTP-binding protein suggest roles of PLD in intracellular vesicle traffi-cking, morphological changes, and mitogenic signaling process. In Saccharomyces cerevisiae, PLD gene has been cloned and revealed to be essential for meiosis. In contrast, little is known about PLD in Candida albicans. As a first step to understand possible physiological roles of PLD in C. albicans, we cloned a PLD gene from a C. albicans genomic DNA library. Deduced amino acid sequence analysis showed the structural similarity to mammalian, yeast, and plant PLDs. It was also suggested employing RT-PCR (reverse transcriptase polymerase chain reaction) that an isozyme of C. albicans PLD was present.

Candida albicans↗
PubMed1998

Association of plasmid integrative J7W-1 prophage with Bacillus thuringiensis strains.

A region homologous to the genome of plasmid integrative phage J7W-1 was detected in the largest plasmid in 3 out of 22 type strains of Bacillus thuringiensis, dendrolimus (DEN), aizawai (AIZ) and indiana (IND). Phage induction by ethidium bromide observed particularly in the J7W-1 lysogen was identified in DEN and IND but not AIZ strains. The morphology of the phage induced in DEN and IND strains was identical to J7W-1, but the phage production in IND strain was lower as compared to the J7W-1 lysogen. Although the restriction analysis indicated that the prophage in DEN strain possessed a complete J7W-1 genome, modification and/or deletion had presumably occurred in AIZ and IND strains.

Bacillus Phages↗
PubMed1998

[Internalized norms and social norms relating to negative health behaviors. The relationship of sociodemographic characteristics and reference groups].

So-called "negative health behaviors" (e.g. smoking, excessive eating/drinking), which are related to morbidity and mortality, are generally well known to the public. However there are many who undertake negative health behaviors despite knowing of their negative health effects. Using a mail survey of subjects aged 25 to 54, we examined reasons and justifications for engaging in negative health behaviors and their related factors from the lay person's perspective. Concerning the reasons for negative health behaviors, we hypothesized seven concepts (work priority, group harmony priority, the contribution to relaxation, tools for communication, prior orientation focused on the present, individualistic priority, and appearance), and devised multiple questions for each concept. The results are as follows. 1. Compared to females, males tended to support of the five concepts about the internalized norms concerned with negative health behaviors (e.g. the tendency of each individual to approve or disapprove of the reasons for negative health behaviors). In females, the younger generation and those that were married expressed more support than the older and the unmarried. There were differences in males according to occupation. 2. Concerning which reference groups had the largest influence on the social norms concerned with negative health behaviors (e.g. the perceptions as to what degree a group regards the reasons about negative health behaviors as desirable), most perceived that the "office" and "friends" groups would be more supportive of reasons for negative health behaviors than the "family" groups. 3. The health behaviors, which correlated with the internalized norms or the social norms concerned with negative health behaviors, were eating breakfast, smoking, and drinking (frequency and amount). In particular, drinking behavior was influenced most by the internalized norms and the social norms.

Adult↗
PubMed1997

Evaluation of human conjunctival epithelium by a combination of brush cytology and flow cytometry: an approach to the quantitative technique.

Cytology using the brush technique is readily available and is a rapid means of establishing a presumptive diagnosis of ocular surface changes. However, those techniques have some limitations when obtaining cells from certain localized areas particularly if using the Cytobrush-S. We have described here a new type of brush (Accellon-M), which can collect the local cells using its spherical tip, and evaluated them by comparing with Cytobrush-S. Furthermore, we differentiated epithelial cells from nonepithelial cells that were collected by brushing, and by a combination of brush cytology and flow cytometry using an anti-keratin antibody, AE-3, which reacts with all basic epithelial keratins. Accellon-M could collect the epithelial cells from conjunctiva as effectively as with the Cytobrush-S, and there were no statistical differences between both groups. AE-3, which is reported as the marker of epithelial cells, were detected quantitatively by a combination of brush cytology and flow cytometry techniques. The result of the present study emphasizes that both the Cytobrush-S and the Accellon-M are valuable for conjunctival brush cytology. An additional positive feature of the Accellon-M may be improved cell collection from the conjunctival epithelium especially when the target cells are in a limited area. The combination of the brush cytology and the flow cytometry technique appears to be a useful adjunct as an additional diagnostic or research tool for use in the detection of various antigens in the conjunctival epithelium.

Adult↗
PubMed1997

Is there circadian variation of plasma endothelin (ET-1) in patients with systemic scleroderma (SSc)?

Forty-three patients with systemic scleroderma (SSc), 10 with non-SSc (6 cases of systemic lupus erythematosus and 4 cases of dermatomyositis), 14 cases of mild- or non-sclerotic type of scleroderma with capillaroscopic abnormalities of nailfolds (SSD; scleroderma spectrum disorders) and 10 healthy volunteers (HC) were subjected to examination of plasma levels of endothelin-1 (ET-1). The sex ratios (male/female) in the patients with SSc, non-SSc and HC were 7:36, 4:6 and 0:10, and the ranges of their ages were 22-74, 19-78 and 33-62 years old, respectively. The plasma levels of ET-1 in SSD, SSc (Barnett I;15), SSc (Barnett II;16), SSc (Barnett III;12 cases), non-SSc and HC were 1.67 +/- 0.37 2.04 +/- 0.58 2.04 +/- 0.68 1.85 +/- 041 191 +/- 0.7 and 1.31 +/- 0.34 pg/ml, respectively, confirming previous results from other laboratories. The plasma levels of ET-1 statistically differ between each collagen disease (SSD, SSc and non-SSc) and HC using Student's t-test (P < 0.05). Although a statistically significant difference was obtained in the plasma levels of ET-1 between the SSc group (6 cases) and HC (6 cases) measured at 06:00, 12:00, 18:00 and 24:00 h, there was no significant circadian variation of plasma levels of ET-1 at these times in both the SSc group and HC. The present study revealed that (1) the ET-1 level in HC showed no circadian fluctuation, and remained at a low level (0.8-1.6 pg/ml). (2) When compared to HC, ET-1 in blood plasma of patients with SSc was elevated (0.3-3 pg/ml) throughout the day and night (P < 0.05). (3) ET-1 tended to increase more at midnight (24:00 h) in the SSc group without PSL treatment, though no statistical significance was obtained. (4) TAT showed a significant increase at noon (12:00 h) suggesting coagulation activity in patients with SSc, but PlC did not show a significant increase compared to HC. In conclusion, the observed increase of vasoconstrictive ET-1 in the patients with SSc throughout the day and night may make maintenance of peripheral blood flow more difficult, may have some biological origin and should be further investigated.

Adult↗
PubMed1997

Pemphigus IgG activates and translocates protein kinase C from the cytosol to the particulate/cytoskeleton fractions in human keratinocytes.

We have demonstrated previously that pemphigus vulgaris (PV)-IgG induces activation of phospholipase C (PLC), production of inositol 1,4,5-trisphosphate, and a rapid transient increase in [Ca2+]i in cultured human keratinocytes, leading to secretion of plasminogen activator and cell-cell detachment in cell culture. In the current study, to examine the involvement of protein kinase C (PKC) in the mechanism of blister formation in PV, we studied the PV-IgG-induced translocation of PKC isozymes from the cytosol to the particulate/cytoskeleton (p/c) fractions and the activation of PKC in human keratinocytes. Cells cultured in Eagle's minimum essential medium were incubated with PV-IgGs for 30 s, 1 min, 5 min, or 30 min. PV-IgG binding to the cell surface antigen (desmoglein III) induced translocation of PKC-alpha from the cytosol to the p/c fractions within 30 s, with a peak at 1 min that lasted at least 30 min. PKC-delta also was translocated within 1 min and reached a peak at 5 min but was reduced to basal levels at 30 min. Alternatively, PKC-eta translocation to the p/c fraction was induced slowly, taking more than 5 min, and was reduced to approximately half-maximum at 30 min, whereas PKC-zeta translocation reached a maximum at 30 s, rapidly returning to baseline by 5 min after PV-IgG stimulation. The total PKC activity in the p/c fraction also was increased after PV-IgG exposure, peaked at 1 min, and was sustained for at least 30 min. These findings suggest that a unique activation profile of PKC isomers may be involved in mediating the intracellular signaling events induced by PV-IgG binding to desmoglein III in cultured human keratinocytes.

Cells, Cultured↗
PubMed1997

Pemphigus IgG induces expression of urokinase plasminogen activator receptor on the cell surface of cultured keratinocytes.

We previously found that the binding of pemphigus IgG to desmogleins caused marked activation of phospholipase C, a transient increase in inositol 1,4,5-trisphosphate production, and a concomitant increase in the intracellular calcium concentration in DJM-1 cells, a squamous cell carcinoma line. The binding of pemphigus IgG to cell membranes increased the activity of urokinase plasminogen activator in culture medium and induced subsequent cell-cell detachment in DJM-1 cells. Because urokinase plasminogen activator activates the conversion of plasminogen to plasmin by binding to urokinase plasminogen activator receptor evading inhibitors in serum, it is likely that plasmin is generated only in microenvironments adjacent to urokinase plasminogen activator receptor on the cell surface. It is not known whether pemphigus IgG causes acantholysis by inducing urokinase plasminogen activator receptor expression on the cell surface and secreting urokinase plasminogen activator in inhibitor-rich environments. We examined the effects of pemphigus IgG on urokinase plasminogen activator receptor expression in DJM-1 cells and normal keratinocytes by immunoblot analysis and immunofluorescence microscopy using antibodies to urokinase plasminogen activator receptor. IgG were obtained from serum samples from eight patients with bullous pemphigoid, five patients with pemphigus vulgaris, seven patients with pemphigus foliaceus, and eight normal subjects. Pemphigus vulgaris and pemphigus foliaceus IgG significantly increased the urokinase plasminogen activator receptor expression on the surface of DJM-1 cells and normal keratinocytes after 3- and 7-d incubation compared with normal IgG. These results suggest that enhanced urokinase plasminogen activator activity and urokinase plasminogen activator receptor expression activates plasmin in the limited cell surface of pemphigus IgG-bound keratinocytes and may contribute to the pathogenesis of differential acantholysis in pemphigus vulgaris and pemphigus foliaceus.

Adult↗
PubMed1997

Differentiation of eccrine poroma cells to cytokeratin 1- and 10-expressing cells, the intermediate layer cells of eccrine sweat duct, in the tumor cell nests.

It has been shown that an intermediate cell layer exists between a luminal cell layer and a peripheral cell layer in human eccrine sweat ducts by immunohistochemistry using anti-keratin antibodies 34 beta B4 and DE-K10. These antibodies react to cytokeratin 1 and 10 respectively, and stain the intermediate cells specifically, but not luminal cells nor peripheral cells. Cytokeratin 1 and 10 are considered to appear as a differentiated keratin in the terminal process of epidermal keratinization. We examined 5 cases of eccrine poroma with 34 beta B4 and DE-K10. Various numbers of the poroid cells reacted to these anti-keratin antibodies in 4 cases. Some positive cells were observed around the cuticular cells in two of them. The present study demonstrated that terminal differentiation in terms of keratinization can occur in eccrine poromas, and that the 34 beta B4- and DE-K10-positive cells around the cuticular cells differentiate toward the intermediate cells in cytokeratin expression profile and location.

Acrospiroma↗
PubMed1997

Skin infection caused by Mycobacterium avium.

A patient with skin infection due to Mycobacterium avium is reported. A 9-year-old female had 10 subcutaneous nodules and two ulcers on the abdomen and legs. She had no medical history of systemic disease, skin disease or immunosuppressive therapy. Cultures of a biopsy specimen and of aspirated seropurulent fluid in nodules showed acid-fast bacteria, identified as M. avium by the DNA-DNA hybridization method. We treated her with a combination of surgery and the antibiotics, cycloserine, isoniazid and clarithromycin.

Child↗
PubMed1997

[A randomized cross-over comparative study of granisetron alone and combination of granisetron, methylprednisolone and droperidol as antiemetic prophilaxis in CDDP-based chemotherapy for gynecologic cancer].

A cross-over clinical trial was carried out to compare the efficacy and safety of granisetron alone (40 micrograms/kg) as a "single" group, with that of granisetron, methylprednisolone (250 mg/ body) and droperidol (0.5 ml/body) as a "cocktail" group for control of emesis and vomiting induced by CDDP-based chemotherapy in 68 courses of 34 patients with gynecologic malignancies. At the first course, "single" or "cocktail" drugs were administered at day 1, 2, and 3 of chemotherapy, and at the second course, "cocktail" or "single" drugs in as cross-over fashion. We examined the degree of nausea and frequency of vomiting during the first 7 days of chemotherapy. As for the severity of nausea, the "single" group showed prominent nausea immediately after CDDP and the most severe level at the 3rd or 4th day. The "cocktail" group showed mild symptoms from the next day and it lasted for several days. Vomiting started 12 hours later in the "single" group and the most frequent peak was the 2nd day, whereas the "cocktail" group showed less than one vomiting at the 2nd or 3rd day throughout the treatment. Clinical response (extremely good, good) in the current series of 68 courses of chemotherapy was also evaluated to be 45% and 35% in the "single" group, respectively, against 75% and 20% in the "cocktail" group, respectively. There was no clinical toxicity or side effects in either treatment group. We conclude that the cocktail treatment is very useful for not only acute, but also late emesis in CDDP-based chemotherapy in gynecologic malignancies.

Adolescent↗
PubMed1997

Immunohistochemical, ultrastructural, and molecular features of Kindler syndrome distinguish it from dystrophic epidermolysis bullosa.

BACKGROUND: Kindler syndrome is a rare, inherited skin disease characterized by acral bullae formation, fusion of fingers and toes, and generalized progressive poikiloderma. The purpose of this study was to clarify the nature of the bullous component of Kindler syndrome and to determine whether this inherited skin disorder represents a variant of dystrophic epidermolysis bullosa or a unique independent clinical entity. OBSERVATIONS: Two unrelated patients with Kindler syndrome were studied. Electron microscopy demonstrated marked duplication of the lamina densa, and clefts were observed in areas where the lamina densa was destroyed or obscured. Hemidesmosomes and anchoring fibrils showed normal features. Indirect immunofluorescence revealed normal linear labeling with antibodies against hemidesmosomal components (alpha 6 and beta 4 integrins, BPAG1, and BPAG2) and against anchoring filament components such as uncein, as detected by the 19-DEJ-1 monoclonal antibody. However, antibodies against the 3 respective laminin 5 chains, type IV collagen, and various type VII collagen epitopes (the aminoterminal NC1 domain, the central triple helical collagenous domain, and the carboxyterminal end of the triple helical collagenous domain) revealed a broad reticular staining pattern. Molecular screening of the type VII collagen gene (COL7A1) in the patients and their parents by heteroduplex analysis failed to detect any band shifts indicative of pathologic mutations. CONCLUSIONS: These results suggest that the bullous component of Kindler syndrome is distinct from dystrophic epidermolysis bullosa caused by mutations in the type VII collagen gene. Additionally, the differential distribution patterns of uncein and laminin 5 in the patients' skin samples support the hypothesis that uncein and laminin 5 are different molecules.

Adult↗
PubMed1997

A vesicular variant of bullous pemphigoid with autoantibodies against unidentified 205- and 150-kDa proteins at the basement membrane zone.

We describe a 75-year-old man who developed a vesicular variant of bullous pemphigoid with a distinctive result of immunoblot analysis. Characteristic symptoms consisted of vesiculopapular eruptions with erythematous patches on the arms and legs, many of which fused to form irregularly outlined areas of erythema varying in size. Direct immunofluorescence revealed a linear deposition of IgG at the basement membrane zone of the skin, and indirect immunofluorescence detected circulating IgG autoantibodies at a titre of 1:160, which reacted with the antigens located on the epidermal side of skin split with 1 mol/L NaCl. Immunoblot analysis using epidermal extracts demonstrated the presence of IgG antibodies directed to 150, 205, 240 and 280 kDa proteins as well as to the 180 kDa bullous pemphigoid antigen (BPAG2). All antibodies eluted from nitrocellulose membrane imprints of individual bands with molecular weights of 150, 180 and 205 kDa were found by indirect immunofluorescence to react with the basement membrane zone, whereas those eluted from the bands with molecular weights of 240 and 280 kDa did not. These findings suggest that antibodies directed not only to the 180 kDa BPAG2, but also to 150 and 205 kDa proteins, are involved in the pathogenesis of bulla formation in this patient.

Aged↗
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↗