Search PubMed⌕ Search

Biomedical subjects

R Tsuboi

Publications and source records attributed to R Tsuboi.

At least 91 records · Page 5Linked to original sources
PubMed1988

Comparison of proteinase activities in squamous cell carcinoma, basal cell epithelioma, and seborrheic keratosis.

The correlation between proteinase activities and invasive and metastatic potentials was investigated by comparing three different kinds of tumors. Extracts from tumor homogenate of 11 squamous cell carcinoma (SCC), 5 basal cell epithelioma (BCE), and 8 seborrheic keratosis (SK) were prepared in order to examine the activity of acid phosphatase and proteinases such as cathepsin B and D, type I and IV collagenase, and plasminogen activator (PA). There was no difference observed between acid phosphatase and cathepsin D activities among the three tumors. Cathepsin B and PA activities were slightly elevated in SCC. Type I collagenase activity of SCC was 9-fold higher than that of SK (p less than 0.01), and type IV collagenase was 3-fold higher per tissue DNA (p less than 0.05). Type I and IV collagenase of BCE were elevated per tissue protein but not elevated per tissue DNA. Correlation was found between the level of cell differentiation in SCC and the activities of cathepsin B, PA, and type I collagenase. Poorly differentiated SCC exhibited a tendency to have higher proteinase activities. Proteinases that showed high activities in malignant tumor homogenate may be related to the degradation of the surrounding cell matrix in addition to intracellular metabolism. Type I and IV collagenase, in cooperation with cathepsin B and PA, might play a major role in invading the dermal stroma and basement membrane.

Basal Cell Carcinoma↗
PubMed1988

Influence of culture medium pH and proteinase inhibitors on extracellular proteinase activity and cell growth of Sporothrix schenckii.

Sporothrix schenckii produces two extracellular proteinases in albumin- or collagen-supplemented unbuffered liquid medium. Proteinase I had an optimal pH of 6.0, and its activity was strongly inhibited by chymostatin. Proteinase II had an optimal pH of 3.5, and its activity was strongly inhibited by pepstatin. Speculating that these two proteinases are key enzymes for fungal growth, we investigated the influences of culture medium pH and either or both of the proteinase inhibitors pepstatin and chymostatin on the cell growth of S. schenckii. In buffered medium at a pH of 3.5, an optimal pH for proteinase II, only proteinase II activities were observed, while at pH 6.0, an optimal pH for proteinase I, only proteinase I activities were observed. However, there was no cell growth inhibition. These results suggested that the regulation of the production of the two proteinases is dependent on environmental pH. The addition of pepstatin or chymostatin to the culture medium did not inhibit the cell growth of S. schenckii, but the addition of both inhibitors at a concentration of 10 micrograms/ml strongly inhibited growth. These results suggested that at least one of the two proteinases was expressed to allow fungal growth in albumin-supplemented media. The indirect fungistatic action of the proteinase inhibitors, which inhibit proteolysis, may be applied to a topical therapeutic agent in vivo.

Chymotrypsin↗
PubMed1987

Isolation and properties of extracellular proteinases from Sporothrix schenckii.

Sporothrix schenckii, mainly in the yeast form of the organism, produced extracellular proteinases when cultivated in liquid media containing albumin or collagen as a nitrogen source, but did not do so in brain heart infusion medium. Isolation of two extracellular proteinases from albumin-containing medium was performed by chromatography on DEAE-Sepharose CL-6B and Sephacryl S-200. Proteinase I had a molecular weight of 36,500, an optimal pH at 6.0, and a pI at 4.8. Despite its activities in weakly acidic conditions, proteinase I demonstrated chymotrypsinlike characteristics, these being indicated by strong inhibitory activity by phenylmethylsulfonyl fluoride and chymostatin and good kinetic constants for a synthetic chymotrypsin substrate, Suc-Ala-Ala-Pro-Phe-MCA. Proteinase II had a molecular weight of 39,000, an optimal pH at 3.5, and a pI at 3.8. Proteinase II showed cathepsin D-like characteristics, these being indicated by strong inhibitory activity by pepstatin, an acidic optimal pH, and good kinetic constants for hemoglobin. These two enzymes hydrolyzed natural substrates such as stratum corneum, type I collagen, and elastin although not type IV collagen. Proteinase production and cell growth in collagen-containing medium and the enzymatic digestion of skin constituents by isolated proteinases suggested that these two proteinases cooperatively enable the organism to invade skin and to obtain peptides from insoluble proteins.

Chromatography, DEAE-Cellulose↗
PubMed1987

Relationship between Candida albicans producing proteinase (CAPP) and its environmental pH--comparison with a case of trichophyton mentagrophytes.

Candida albicans produced a karatinolytic proteinase (KPase) or C. albicans producing proteinase (CAPP), a proposed new term for this enzyme, and Trichophyton mentagrophytes also produced KPase when cultivated in liquid medium containing human stratum corneum (HSC) as the nitrogen source, but were unable to do so when cultivated in sabouraud dextrose broth. Purified KPase from the culture supernatants of C. albicans had a molecular weight of 42,000 and an optimum pH at 4.0. The KPase was found to belong to the carboxyl proteinases group and its activity was strongly inhibited by pepstatin. Both fungi were able to grow by secreting KPase which digested HSC for nutrients. KPase from both fungi had high activity in each optimum pH, such as weakly acidic pH on C. albicans and neutral pH on T. mentagrophytes to adapt their surrounding environment by changing the environmental pH into their own optimum pH.

Candida albicans↗
PubMed1986

Induction and inhibition of cathepsin B and hemoglobin-hydrolase activity in murine B16 melanoma by thiol protease inhibitors.

The effects of potent thiol protease inhibitors in vitro (leupeptin, antipain, chymostatin and E-64 (N-[N-(L-3-trans-carboxyoxirane-2-carbonyl)-L-leucyl]agmatine) on intracellular cathepsin B and hemoglobin (Hb)-hydrolase from cultured B16 melanoma cells were studied. E-64 induced cultured B16 melanoma cells to decrease the activities of intracellular cathepsin B (EC 3.4.22.1.) but did not have this effect with Hb-hydrolase or acid phosphatase (EC 3.1.3.2). Leupeptin, antipain and chymostatin induced B16 melanoma cells to increase the activities of intracellular cathepsin B and Hb-hydrolase but not that of acid phosphatase. These results indicate that there are two kinds of thiol protease inhibitors, each with a varying reaction to cultured B16 melanoma--inhibition of intracellular cathepsin B, and conversely, inducement of both cathepsin B and Hb-hydrolase.

Animals↗
PubMed1986

Lymphocutaneous nocardiosis caused by Nocardia asteroides. Case report and literature review.

A 22-year-old man developed erythematous nodules and an ulcer mimicking sporotrichosis on his right hand and forearm, which was subsequently diagnosed as lymphocutaneous nocardiosis caused by Nocardia asteroides. To our knowledge, 21 cases of lymphocutaneous nocardiosis have been reported, with the majority of those cases, except for a few that remain uncertain, being due to Nocardia brasiliensis. The case reported herein, the first known definitive case caused by N asteroides (to our knowledge), showed a more chronic course and less inflammatory manifestation compared with that caused by N brasiliensis. This is probably because N brasiliensis has a stronger virulence than N asteroides.

Adult↗
PubMed1984

Isolation and characterization of proteinase from Candida albicans: substrate specificity.

Candida albicans was able to produce a keratinolytic proteinase (KPase) when cultivated in a medium containing human stratum corneum as a nitrogen source. The KPase was purified to 108.5-fold by ion-exchange chromatography and gel filtration. The molecular weight of the enzyme was estimated to be 42,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration through Sephacryl S-200, while the isoelectric point was determined to be at pH 4.5. The enzyme had an optimum pH of 4.0 and was "inactive" below pH 2.5 and above pH 6.0. The activity of KPase after preincubation at various temperatures was stable up to 50 degrees C. The keratinolytic activity was not affected by the addition of nonionic detergents and divalent cations. The enzyme was a glycoprotein and contained a high content of aspartic acid residues (172/1000). Pepstatin and chymostatin inhibited the activity in a dose-dependent manner; however, neither the other group specific inhibitors tested nor the pepsin specific inhibitors, DAN or EPNP, showed any effect on the enzyme. From these inhibitory profiles, this enzyme was determined to be a carboxyl proteinase such as cathepsin D. Among the various substrates for proteolytic enzymes, KPase digested human stratum corneum as much as albumin and hemoglobin. In the three fractions (water soluble, keratin filamentous, and membranous) prepared from human stratum corneum, the keratin filamentous fraction was more susceptible to degradation by KPase than the other two fractions were. KPase also digested much less human fingernail (13%) than human stratum corneum, but did not show any signs of there being any digestion of human scalp hair. These studies suggest that KPase from C. albicans may play an important role in superficial infection by affecting the human stratum corneum of the skin and nail.

Candida albicans↗
PubMed1984

beta-Galactosidase and neuraminidase deficiency associated with angiokeratoma corporis diffusum.

A 17-year-old Japanese boy was found to have ataxia, generalized angiokeratomas, skeletal deformities, visual impairment, and macular cherry-red spots, without hepatomegaly, splenomegaly, or renal failure. Laboratory examination disclosed a deficiency of beta-galactosidase as well as of neuraminidase activity in the leukocytes and fibroblasts, while alpha-galactosidase and alpha-L-fucosidase activities were normal. On electron microscopic examination, numerous cytoplasmic vacuoles containing flocculated material were found in the vascular endothelial cells, histiocytes, perineurial cells, and Schwann's cells.

Adolescent↗