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Biomedical subjects

R Tsuboi

Publications and source records attributed to R Tsuboi.

At least 55 records · Page 3Linked to original sources
PubMed1995

A case of Behçet's disease aggravated by gingival infection with methicillin-resistant Staphylococcus aureus.

We report a case of Behçet's disease aggravated by gingivitis and carious teeth infected with methicillin-resistant Staphylococcus aureus. Recurrent severe ulcers in the mouth, and on the genitalia and legs were closely linked with the infection, and dramatically improved after extraction of the carious teeth and administration of systemic vancomycin hydrochloride.

Anti-Bacterial Agents↗
PubMed1995

A case of angiocentric T-cell lymphoma presenting as lethal midline granuloma.

A case of angiocentric T-cell lymphoma with glabellar skin being the only affected site was reported. A 43-year-old woman had a several months' history of glabellar swelling followed by progressive and destructive ulceration of the region. Histopathology of the biopsied specimen showed panniculitis with atypical lymphocytes and degenerative vessels filled with atypical cells. Most of the infiltrated lymphocytes were positive for CD2, CD3, CD4 and CD5. Antibodies to Epstein-Barr virus were detected in the patient serum. Intensive chemotherapy using a protocol of the L17M regimen was partially effective for clinical manifestations. Angiocentric T-cell lymphoma presenting as lethal midline granuloma is a rare but distinct entity with an acute fatal course.

Adult↗
PubMed1994

Endothelin-1 acts as an autocrine growth factor for normal human keratinocytes.

Endothelin-1 (ET-1) is an endothelium-derived 21 amino acid vasoconstrictor peptide possessing two intrachain disulfide bridges. Recently it has become evident that isoforms of ET (ET-1, -2, and -3) have a wide range of pharmacological effects in various tissues and act as autocrine/paracrine factors. We demonstrate here that ET-1 is secreted from normal human keratinocytes and may work as an autocrine growth factor through a specific receptor. In this study, human foreskin keratinocytes were cultured in serum-free MCDB 153 medium. Cell growth and [3H] thymidine incorporation in low and high Ca++ concentration media was stimulated by ET-1, -2, and -3 with similar potencies. The strongest response was observed at 10 nM ETs, whereas stimulatory activity was reduced at 100 nM. ETs suppressed keratinocyte differentiation as measured by reactivity with involucrin antibody. Plasminogen activator activity (mainly urokinase) in the medium was also stimulated by the addition of 10 nM ETs. ET-1-like immunoreactivity measured by radioimmunoassay was 1.4 fmol/day/10(6) cells in non-treated condition medium. Among the various cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-1 alpha, and transforming growth factor-beta stimulated ET-1 secretion in a dose-dependent manner. The strongest response (ten-fold) was observed upon the addition of 10 ng/ml TNF-alpha. Scatchard plot analysis of [125I] ET-1 binding to keratinocytes revealed the presence of a single class of high affinity receptors (KD 50 pM, 9 x 10(3) sites/cell). Binding was competitively inhibited by the addition of unlabeled ET-1 and -2 with similar affinities and by ET-3 with weaker affinity. ET-1 mRNA expression in keratinocytes was detected by reverse transcription-polymerase chain reaction and was increased by treatment with 10 ng/ml TNF-alpha. These results suggest that ET-1 acts as an autocrine growth factor for keratinocytes through a specific receptor.

Base Sequence↗
PubMed1994

The effect of various cytokines on hair growth of mouse vibrissae in organ culture.

Hepatocyte growth factor/scatter factor (HGF) is a multifunctional polypeptide which acts as a mitogen, motogen or morphogen depending on the biological context. In this study, we examined the effect of HGF on hair growth using a serum-free organ culture system. Vibrissal hair follicles isolated from newborn mice were cultured at 31 degrees C in 95% O2-5%CO2 for 72 h in the presence of various cytokines or growth factors. DNA, protein synthesis and elongation of the hair shaft in the hair follicles were measured. Among the agents tested, only HGF significantly increased hair follicle length (P < 0.001) and 3H-thymidine (P < 0.001) incorporation. The effect of HGF was dose-dependent, with maximal stimulation obtained at 10 ng/ml. The increase in hair follicle length and thymidine incorporation were specifically inhibited by a neutralizing antibody against HGF. These results indicate that HGF is able to promote hair growth and may have clinical utility in this regard.

Animals↗
PubMed1994

Hepatocyte growth factor/scatter factor stimulates hair growth of mouse vibrissae in organ culture.

Hepatocyte growth factor/scatter factor (HGF/SF) is a multifunctional polypeptide that acts as a mitogen, motogen, or morphogen, depending on the biologic context. In this study, we examined the effect of HGF/SF on hair growth using a serum-free organ culture system. Vibrissal hair follicles isolated from newborn mice were cultured at 31 degrees C in 95% O2/5% CO2 for 72 h in the presence of various cytokines or growth factors, and elongation of hair shaft, DNA, and protein synthesis in hair follicles were measured. Among the agents tested, only HGF/SF significantly increased hair follicle length (p < 0.001), 3H-thymidine (p < 0.001), and 35S-cysteine (p < 0.05) incorporation. The effect of HGF/SF was dose dependent, with maximal stimulation obtained at 10 ng/ml. The increase in hair follicle length and thymidine incorporation were specifically inhibited by a neutralizing antibody against HGF/SF. These results indicate that HGF/SF can promote hair growth and may have clinical utility in this regard.

Animals↗
PubMed1994

Scanning electron microscope observation of adherence of Candida albicans to cultured keratinocytes.

The role of antigen 6 in the adherence process of Candida albicans serotype A to cultured keratinocytes was examined with a scanning electron microscope. The number of adhered organisms was significantly lower for the antigen 6-deficient mutant strain than for the antigen 6-positive parent strain (P < 0.001). Fibril- or strand-like structures bridging the organisms and the keratinocytes were found to develop during the later stages of adherence.

Bacterial Adhesion↗
PubMed1993

Keratinocyte growth factor (FGF-7) stimulates migration and plasminogen activator activity of normal human keratinocytes.

Keratinocyte growth factor (KGF), a member of the fibroblast growth factor (FGF) family (and alternatively designated FGF-7), is a paracrine growth factor produced by mesenchymal cells and mitogenic specifically for epithelial cells. The potential effect of KGF on wound healing was assessed in vitro by measuring randomized migration and plasminogen activator (PA) activity of keratinocytes in response to the growth factor. Incubation of normal human keratinocytes with KGF in modified MCDB 153 medium significantly stimulated cell migration and PA activity compared with control (p < 0.001 and p < 0.01, respectively). When tested in these assays on an equimolar basis, 1 nM KGF was at least as potent as transforming growth factor alpha and more active than basic FGF. None of these effects were observed when KGF was administered to fibroblasts or endothelial cells. Stimulation of keratinocyte migration by KGF was dose dependent, and a neutralizing monoclonal antibody against KGF reduced KGF-stimulated migration and cell growth. Zymographic analyses of cell extracts and conditioned medium from KGF-treated keratinocytes revealed increased PA activity, which was mainly attributable to an elevated level of urokinase-type PA. These in vitro results suggest that KGF may have an important role in stimulating reepithelialization during the process of wound repair.

Cell Movement↗
PubMed1993

Immunohistochemical localization of basic fibroblast growth factor in skin diseases.

The basic fibroblast growth factor (bFGF) is an angiogenic factor and also a mitogen for epidermal keratinocytes. In order to investigate the role of bFGF in human skin we examined the distribution of bFGF immunoreactivity in normal and diseased human skin. Antigen expression was demonstrated by direct immunofluorescence staining of cryostat sections with a polyclonal anti-bFGF antibody. In normal human skin, bFGF-like immunoreactivities were observed in the basal cells, while in the case of psoriasis, positive immunoreactivities were observed in the basal cells and several supra-basal layers at rete ridges. Seborrheic keratosis and basal cell epithelioma showed diffuse immunoreactivities in the basaloid cells of the tumor. Concurrently, benign nevus cell nevus, capillary hemangioma, squamous cell carcinoma and malignant melanoma displayed negative immunoreactivities. These results suggest that bFGF is important for basal or basaloid cell proliferation.

Biopsy↗
PubMed1992

Immunohistochemical localization of basic fibroblast growth factor in wound healing sites of mouse skin.

The immunohistochemical localization of basic fibroblast growth factor (bFGF) was examined during wound healing in mouse skin. Frozen sections taken from the rounded skin defects were reacted with polyclonal anti-human recombinant bFGF IgG followed by incubation with FITC-conjugated IgG. The basal layer keratinocytes and hair bulbs at the wound edge were strongly stained with this antibody. In the reepithelized area, several layers of keratinocytes from the basal layer were positively stained regardless of the time after wounding. These findings suggest that germinative keratinocytes which express bFGF function as leading cells in the covering of the wound defect. However, dermal granulation tissue, including capillary endothelial cells, fibroblasts and macrophages unexpectedly did not demonstrate any immunoreactivity throughout the process of wound healing. Simultaneous histochemical investigation using cultivated mouse keratinocytes and bovine aortic endothelial cells showed primarily cytoplasmic fluorescence. The discrepancy in the staining patterns of endothelial cells in vivo and in vitro suggests that immunoreactive bFGF is either not expressed in vivo, or is processed or masked.

Animals↗
PubMed1992

Stimulation of keratinocyte migration by growth factors.

Migration of keratinocytes from the wound edge is thought to be one of the critical features of reepithelialization. A quantitative migration assay was carried out using normal human keratinocytes. Keratinocytes, seeded on 12 well plates, were grown in serum free, keratinocyte growth medium (KGM, Curabo Co) with 0.08 mM Ca2+. The medium was switched from KGM to keratinocyte basal medium (KBM) 6 h prior to the wounding. Half of the plate's confluent monolayer of keratinocytes was removed with razor blade, and the remaining keratinocytes were incubated in KBM for 16 hrs in the presence of indicated growth factors. After incubation, the cells were fixed and counted at 100 magnification. Migration was quantitated by counting the number of cells in ten successive 125-microns zones. Transforming growth factor alpha (TGF-alpha), acidic and basic fibroblast growth factor (aFGF, bFGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), and insulin-like growth factor-I (IGF-I) stimulated the migration of keratinocytes, while TGF-beta suppressed it.

Cell Movement↗
PubMed1992

A wound healing model using healing-impaired diabetic mice.

A quantitative histological approach was employed to evaluate the effects of basic fibroblast growth factor (bFGF) in healing-impaired diabetic mice. The dorsal areas of female mutant diabetic mice, C57BL KsJ db/db (Jackson Lab.), were given two 6 mm-size full thickness wounds with a punch biopsy instrument. After application of bFGF, the wounds were left open. 8 days after wounding, the mice were sacrificed, and histological sections were evaluated using several histological parameters, such as the degree of wound closure, granulation tissue thickness, matrix density, and capillary numbers. Application of 5 micrograms of bFGF for 5 days induced significant responses by all of these dermal parameters when compared to those of non-treated db/db mice (p < 0.001). A minimum of 0.5 micrograms bFGF per day was required for a significant effect. Time-course experiments indicated that the granulation response in bFGF-treated mice peaked between 8 and 12 days and decreased after 12 days, while matrix density continued to increase until the 18th day.

Animals↗