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Biomedical subjects

K Iwatsuki

Publications and source records attributed to K Iwatsuki.

At least 109 records · Page 6Linked to original sources
PubMed1995

The feline herpesvirus type 1 ICP4 down-regulates feline immunodeficiency virus long terminal repeat (LTR)-directed gene expression via the C/EBP site in the LTR.

We investigated effects of feline herpesvirus type 1 (FHV-1) ICP4 on feline immunodeficiency virus (FIV) long terminal repeat (LTR)-directed gene expression by transient transfection assay in Crandell feline kidney cells. We demonstrated that FHV-1 ICP4 significantly stimulates the FIV LTR after introduction of site-specific mutation of the C/EBP site in the LTR, and the C/EBP site is sufficient to confer inhibitory effects by FHV-1 ICP4 on a heterologous promoter. These results indicate that FHV-1 ICP4 possesses both ability to transactivate FIV LTR-directed gene expression and to down-regulate the FIV LTR via the C/EBP site.

Animals↗
PubMed1995

Serological survey of canine distemper virus infection using enzyme-linked immunosorbent assay.

For detection of antibodies against canine distemper virus (CDV), an enzyme-linked immunosorbent assay (ELISA) was developed using a crude extract from cells infected with the Onderstepoort strain of CDV as antigen. Twenty-six sera from dogs experimentally vaccinated with the Snyder-Hill strain of CDV were compared by ELISA and a standard virus neutralization (NV) test. Since a good correlation between the titers obtained by both tests was observed, ELISA was considered to be a rapid and reliable method for a serological survey of CDV infection. When a total of 167 sera from dogs suspected of canine distemper under natural conditions were examined by the ELISA, 29 of the sera (17%) were found to have low VN antibody titers and high ELISA titers. The reason for the discrepancy in the titers was discussed.

Animals↗
PubMed1995

A case of bullous pemphigoid with antibodies against intercellular 130 kd antigen.

Pemphigus and bullous pemphigoid are two typical autoimmune bullous diseases that involve circulating autoantibodies directed against the epidermal cell surface and the epidermal basement membrane zone, respectively. The coexistence of pemphigus and bullous pemphigoid is rare. We describe a case of a 79-year-old man who had tense bullae and erythematous, erosive lesions on his trunk and four extremities. Histopathology revealed subepidermal blister formation without any evidence of intraepidermal acantholytic changes. Direct immunofluorescence study demonstrated deposition of IgG on the epidermal intercellular spaces, as well as along the basement membrane zone; C3 was detected only on the latter. Indirect immunofluorescence study using monkey esophagus as a substrate demonstrated the presence of circulating antibodies against both junctional and intercellular antigens. In order to analyze the precise nature of this patient's antibodies, indirect immunofluorescence study using cultured human keratinocytes and immunoblot analyses were performed. Pemphigus vulgaris sera showed smooth and uniform staining on intercellular spaces. The patient's serum showed a granular and uneven staining pattern. Immunoblot analysis showed that the patient's serum reacted with the typical 230 kd (bullous pemphigoid) antigen and 130 kd antigen, which is close to the pemphigus vulgaris antigen.

Aged↗
PubMed1994

rbcL gene sequences provide evidence for the evolutionary lineages of leptosporangiate ferns.

Pteriodophytes have a longer evolutionary history than any other vascular land plant and, therefore, have endured greater loss of phylogenetically informative information. This factor has resulted in substantial disagreements in evaluating characters and, thus, controversy in establishing a stable classification. To compare competing classifications, we obtained DNA sequences of a chloroplast gene. The sequence of 1206 nt of the large subunit of the ribulose-bisphosphate carboxylase gene (rbcL) was determined from 58 species, representing almost all families of leptosporangiate ferns. Phlogenetic trees were inferred by the neighbor-joining and the parsimony methods. The two methods produced almost identical phylogenetic trees that provided insights concerning major general evolutionary trends in the leptosporangiate ferns. Interesting findings were as follows: (i) two morphologically distinct heterosporous water ferns, Marsilea and Salvinia, are sister genera; (ii) the tree ferns (Cyatheaceae, Dicksoniaceae, and Metaxyaceae) are monophyletic; and (iii) polypodioids are distantly related to the gleichenioids in spite of the similarity of their exindusiate soral morphology and are close to the higher indusiate ferns. In addition, the affinities of several "problematic genera" were assessed.

Base Sequence↗
PubMed1994

Regulatory effects of 1,25-dihydroxyvitamin D3 and a novel vitamin D3 analogue MC903 on secretion of interleukin-1 alpha (IL-1 alpha) and IL-8 by normal human keratinocytes and a human squamous cell carcinoma cell line (HSC-1).

Pro-inflammatory cytokines mediate their biological functions after they are secreted or released from intracellular to extracellular milieu. Keratinocytes have proven to be able to produce various cytokines including IL-1 and IL-8. Dysregulations of IL-1 and IL-8 were found in psoriatic lesions. Recently, vitamin D3 (VD3) was found to be an effective and safe therapy for psoriasis. In the present study, we investigated the effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and its analogue MC903 on IL-1 alpha and IL-8 secretion by human keratinocytes in vitro. Cultured normal human keratinocytes (NHKs) produced considerable amounts of IL-1 alpha but secreted less. In contrast, they produced less IL-8 and almost all molecules were secreted to the culture supernatants. Treatment of unstimulated NHKs with 1,25(OH)2D3 or MC903 showed little effects on IL-1 alpha production and secretion though they slightly enhanced IL-8. When NHKs were stimulated with tumour necrosis factor-alpha (TNF alpha), both IL-1 alpha and IL-8 secretions were enhanced and these enhancements were inhibited by 1,25(OH)2D3 or MC903. Stimulation of NHKs with phorbol 12-myristate 13-acetate(PMA) and lipopolysaccharide(LPS) resulted in an increase of IL-8 and decrease of IL-1 alpha in the culture supernatants. Addition of 1,25(OH)2D3 or MC903 inhibited the increased secretion of IL-8 but restored decreased secretion of IL-1 alpha from stimulated NHKs dose dependently. Hydrocortisone and cyclosporin A showed similar inhibitory effects on PMA/LPS-increased IL-8 secretion from NHKs but had little effect of restoring IL-1 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcitriol↗
PubMed1994

Lymphomatoid papulosis associated with acquired ichthyosis.

We describe a 64-year-old man with lymphomatoid papulosis associated with acquired ichthyosis. The papulonodular lesions were composed of large atypical lymphocytes positive for CD3, CD4, and Ki-1. The ichthyosiform eruption also occurred on the extremities and had the histologic features of ichthyosis vulgaris. Although monoclonality of infiltrating cells could not be demonstrated, acquired ichthyosis appears to be induced in patients with lymphomatoid papulosis by the same pathomechanism underlying other lymphoproliferative diseases.

CD4-Positive T-Lymphocytes↗
PubMed1994

Detection of Epstein-Barr virus genes in malignant lymphoma with clinical and histologic features of cytophagic histiocytic panniculitis.

T-cell proliferative disorders are occasionally associated with Epstein-Barr virus (EBV) infection. This study was designed to assess the clinical features of cutaneous lymphomas positive for EBV genes. Polymerase chain reaction was used to detect EBV genes in tissue or blood samples from patients with malignant lymphoma or related diseases. Of 26 DNA samples tested, EBV genes were detected in two samples, both of which were obtained from the same patient with subcutaneous T-cell lymphoma showing clinical and histologic features of cytophagic histiocytic panniculitis. On the basis of these findings, we conclude that EBV infection may be related to cutaneous lymphoma with hemophagocytic manifestations.

Adolescent↗
PubMed1994

Prostaglandin E1 protects dog pancreas from ischemia-reperfusion injury.

Effects of prostaglandin (PG) E1 on ischemia-reperfusion (I-R) injury to the pancreas was evaluated using isolated in vivo perfused dog pancreas. Pancreatic endocrine and exocrine functions were stimulated with 10(-12) M cholecystokinin octapeptide (CCK-8). This amount of CCK-8 promoted production of insulin, glucagon, PGI2, and thromboxane (Tx) A2 in the pancreas. Sixty minutes of ischemia and subsequent reperfusion induced damage to pancreatic ductular, acinar, and beta cells. Intra-arterial administration of PGE1 at a dose of 0.5 microgram/kg/min throughout the experiment prevented the I-R injury, reducing plasma lipid peroxides, and elevating PGI2 without changing TxA2 in the pancreas. PGE1 thus appears to protect pancreatic function from I-R injury both by depressing the effect of free-radicals and by decreasing TxA2/PGI2 which predicts cell injury.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Induction of intercellular adhesion molecule-1 and adherence of HTLV-1-infected T-cells to cultured keratinocytes.

Cutaneous lesions of T-cell proliferative disorders are characterized by epidermotropic infiltration of the neoplastic cells and expression of intercellular adhesion molecule-1 (ICAM-1) and HLA-DR by lesional keratinocytes. Using cloned HTLV-1-infected T-cells obtained from patients with adult T-cell leukemia (ATL), we have studied immunobiological activities of cytokines released from the T-cell lines and their ability to adhere to cultured keratinocytes. Three out of the five CD-4-positive, HTLV-1-infected T-cell clones secreted both IFN-gamma and IL-4, similar to murine Th0 clones. The other two clones did not produce such cytokines. ICAM-1 and HLA-DR molecules were induced on cultured normal human keratinocytes and organ-cultured skin specimens by co-cultivation with IFN-gamma-producing T-cell clones or their culture supernatants. Induction of both molecules was markedly inhibited by pretreatment of the supernatants with excess amounts of anti-IFN-gamma monoclonal antibody. The number of cells adherent to the normal cultured keratinocytes was greater in the IFN-gamma-producing clones than in the non-producing ones. These data suggest that some HTLV-1-infected clones produce cytokines, including IFN-gamma, which in turn induce ICAM-1 on keratinocytes, thereby enhancing the ability of the T-cell clones to adhere to the keratinocytes.

Cell Adhesion↗
PubMed1994

Effects of etretinate on keratinocyte proliferation and secretion of interleukin-1 alpha (IL-1 alpha) and IL-8.

Etretinate has proven to be effective in the treatment of psoriasis. Since abnormal proliferation and cytokine secretion are well-known features of psoriatic epidermis, we studied the in vitro effects of etretinate on these two processes using human keratinocytes. Etretinate promoted proliferation of normal human keratinocytes (NHKs) grown in keratinocyte growth medium (KGM) but not in growth factor-deficient keratinocyte basic medium (KBM). Moreover, etretinate partly overcame growth inhibition by PMA. Etretinate was shown to have an effect on either IL-1 alpha or IL-8 secretion in unstimulated NHKs. In HSC-1, a human squamous cell carcinoma cell line cultured in 20% FCS/DMEM, inhibited IL-1 alpha secretion and enhanced IL-8 secretion. These results indicate that the effects of etretinate on keratinocyte proliferation and cytokine secretion may depend on cell type and culture conditions. Stimulation of NHKs with PMA significantly enhanced IL-1 alpha and IL-8 secretion, and these effects were inhibited by etretinate. However, etretinate failed to inhibit rTNF alpha-induced IL-8 secretion, suggesting that etretinate regulation of NHK cytokine secretion may also depend on the stimulus. As treatment of keratinocytes or epidermis with PMA can induce psoriasis-like changes, so might the experimental "anti-PMA" activity of etretinate be related to its therapeutic benefit in the treatment of psoriasis.

Carcinoma, Squamous Cell↗
PubMed1994

Effects of cyclic nucleotide phosphodiesterase IV inhibitor, Ro20,1724, on pancreatic exocrine secretion in dog.

1. The effects of the cyclic nucleotide phosphodiesterase (PDE) inhibitors, Ro20,1724, 3-isobutyl-1-methylxanthine (IBMX), trifluoperazine (TFP) and amrinone on pancreatic exocrine secretion were investigated in anaesthetized dogs in comparison with those of secretion and cholecystokinin octapeptide (CCK-8). 2. Ro20,1724 (1-30 nmol/kg), IBMX (3-30 nmol/kg), secretin (0.01-0.1 pmol/kg) or CCK-8 (0.1-1 pmol/kg) injected i.a. elicited a dose-dependent increase in the secretion of pancreatic juice, but TFP and amrinone (up to 1 mumol/kg) did not. 3. The bicarbonate concentration in pancreatic juice was increased and the protein concentration was decreased by Ro20,1724, IBMX and secretin. Cholecystokinin octapeptide increased the protein concentration but did not alter the bicarbonate concentration. 4. Ro20,1724 and IBMX elicited more than the respective additive secretory response when added together with secretin, although the stimulatory effects of CCK-8 with Ro20,1724 and IBMX were additive. 5. Ro20,1724 and IBMX increased cyclic AMP concentration but did not affect cyclic GMP concentration. 6. These results suggest that Ro20,1724 and IBMX have secretory properties on pancreatic exocrine glands of the dog, which may be mediated through an increase in cyclic AMP subsequent to inhibition of PDE activity. Furthermore, pancreatic PDE enzymes in the dog may be mainly type IV.

1-Methyl-3-isobutylxanthine↗
PubMed1994

Effects of prostaglandin E1 on human keratinocytes and dermal fibroblasts: a possible mechanism for the healing of skin ulcers.

The effects of prostaglandin E1 (PGE1) on cell growth, cytokine production and interaction of cultured normal human keratinocytes (NHKs) and human dermal fibroblasts (HDFs) were investigated. When NHKs were treated with PGE1 directly, only a slight increase in cell growth and a transient decrease in interleukin 1 alpha (IL-1 alpha) secretion were observed. No IL-6 was detected either before or after PGE1 treatment. In addition, IL-8 and transforming growth factor alpha (TGF alpha) production were uninfluenced by PGE1. The response of HDFs to PGE1 differed from that of NHKs. Following PGE1 treatment, IL-1 alpha and TGF alpha from HDFs remained undetectable while IL-6 production was enhanced markedly. IL-8 production was also slightly enhanced. Exposure of HDFs to PGE1 for 96 hours significantly promoted cell proliferation. Two kinds of conditioned media (CM) were prepared by a brief feeding of HDFs with keratinocyte basic medium or Dulbecco's modified Eagle's medium supplemented with 5% FCS with or without PGE1. NHKs proliferated more rapidly in CM than in corresponding basic medium. Moreover, CM prepared with PGE1 treatment showed a stronger effect in promoting NHK proliferation than CM without PGE1 treatment. This promoting effect was inhibited by anti-human IL-6 monoclonal antibody dose-dependently. These results indicate that fibroblasts are more sensitive than keratinocytes in response to PGE1 and that, upon PGE1 stimulation, HDF-derived IL-6 may play an essential role in NHK cell proliferation which may at least partly account for the beneficial effects of PGE1 in the treatment of cutaneous ulcerations.

Alprostadil↗
PubMed1994

Regulation of pemphigus and desmosomal antigen expression by keratinocyte differentiation.

We studied in vivo binding sites of pemphigus antibodies and the expression of pemphigus and desmosomal antigens by keratinocytes in various culture periods. Both pemphigus vulgaris (PV) and pemphigus foliaceus (PF) antibodies mainly bound to the desmosomal areas of the lesional skin. Desmoglein and PV antigens co-localized on the cultured normal human keratinocytes in both monolayers and stratified areas. PF antigens, frequently together with involucrin and suprabasal keratins, were expressed by stratified keratinocytes. The Western blotting study demonstrated two different desmogleins with molecular sizes of 130 and 150 kD. The 130-kD desmoglein bore PV antigenic epitopes. The 150-kD band increased in volume as cultured keratinocytes stratified. PV antigen expression on the 130-kD desmoglein precedes PF antigen formation occurring in keratinocyte differentiation.

Antigen-Antibody Reactions↗
PubMed1994

Evaluation of cytokines in donor site wound fluids.

The aim of the study was to measure concentrations of cytokines in wound fluid from donor sites. A film dressing was applied to the donor sites (mean size 10 x 15 cm) immediately after a split skin graft had been taken. Five days later the film was punctured with a needle and 2-3 ml of the fluid accumulated under the film dressing was withdrawn into a syringe. The fluid was snap frozen and stored immediately at -70 degrees C. The fluid was examined for epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), transforming growth factor (TGF) alpha, TGF beta, interleukin (IL)-1 alpha and IL-1 beta. The results showed that the fluid accumulated under the film dressing contained growth factors and cytokines that are thought to promote healing. The fluid was rich in TGF alpha but contained no EGF or bFGF, which indicates that TGF alpha plays a major part for promoting local wound healing.

Adult↗
PubMed1993

Effects of KRN2391, a novel vasodilator, on pancreatic exocrine secretion in anesthetized dogs.

The effects of KRN2391, a newly synthesized vasodilator, on pancreatic exocrine secretion in anesthetized dogs were compared with those of Ki3315, pinacidil and nitroprusside. Graded doses of KRN2391 (0.03-3 mumol/kg) and nitroprusside (0.003-0.3 mumol/kg) injected i.a. produced dose-dependent increases in the secretion of pancreatic juice, with a high concentration of protein and low concentration of bicarbonate, but Ki3315 or pinacidil did not (up to 10 mumol/kg). KRN2391 and nitroprusside increased the cyclic GMP levels in pancreatic tissue together with the increase in pancreatic secretion. Methylene blue decreased pancreatic secretion and cyclic GMP levels stimulated by KRN2391 and nitroprusside, but glibenclamide did not. KRN2391, Ki3315, pinacidil and nitroprusside caused vasodilator actions. These results suggest that KRN2391 has direct secretory properties on pancreatic exocrine glands of the dog and its nitro moiety has an important role in the stimulation of pancreatic secretion, but the K+ channel opening action or increasing of blood flow rate does not participate in the secretion.

Animals↗
PubMed1993

Dual actions of glucagon: direct stimulation and indirect inhibition of dog pancreatic secretion.

The secretory actions of glucagon on the exocrine pancreas were examined using two kinds of canine preparations. In the isolated and blood-perfused dog pancreas with venous drainage, i.a. injection of glucagon did not inhibit secretin/cholecystokinin-octapeptide (CCK-8)-stimulated pancreatic secretion, but instead dose dependently enhanced both basal and stimulated pancreatic secretion. Glucagon-induced increase of pancreatic secretion was potentiated by 3-isobutyl-1-methylxanthine. In contrast, i.v. bolus injection of glucagon (3 and 10 nmol/kg) first augmented transiently then suppressed secretin/CCK-8-stimulated pancreatic secretion while simultaneously increasing circulating plasma somatostatin immunoreactivity from 14.2 to 214 fmol/ml in anesthetized intact dogs. The inhibition of secretin/CCK-8-stimulated pancreatic secretion and elevation of plasma somatostatin immunoreactivity induced by glucagon were comparable with those due to somatostatin-14. Thus, these results indicate that glucagon stimulates pancreatic secretion directly; the inhibitory action of glucagon is indirect and appears to be related to a rise in the circulating level of somatostatin immunoreactivity.

1-Methyl-3-isobutylxanthine↗