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Biomedical subjects

K Hosokawa

Publications and source records attributed to K Hosokawa.

At least 55 records · Page 3Linked to original sources
PubMed2000

Theophylline and cisplatin synergize in down regulation of BCL-2 induction of apoptosis in human granulosa cells transformed by a mutated p53 (p53 val135) and Ha-ras oncogene.

Cisplatin is in common use in ovarian cancer therapy, although it is also implicated in cytotoxicity in normal tissue. We have examined the effect of cisplatin alone and in combination with theophylline, a phoshodiesterase inhibitor, on modulation of Bcl-2/Bax expression and induction of apoptosis in human granulosa cells transformed by stable transfection with mutant p53 plus Ha-ras. Theophylline elicited cell death only at relatively high concentrations with an EC50 of 200 microg/ml. Cisplatin exerted its lethal effect with an EC50 of 7 microM. In the presence of 15 or 50 microg/ml of theophylline (in the range used against asthma in humans), the EC50 for cisplatin was reduced to 2 microM or 1.2 microM, respectively. Using fluorescence-activated cell sorting analysis of DNA stained cells and the terminal deoxy-nucleotide tranferase-mediated dUTP nick end-labeling method, we found that even at concentrations of 0. 3 and 1 microM cisplatin, theophylline at 15 and 50 microg/ml increased the incidence of apoptosis in these cells by 3-5-fold, while theophylline alone induced extremely low apoptosis. Neither drug had any measurable effect on Bax protein expression. In contrast Bcl-2 protein expression levels were markedly reduced by theophylline and cisplatin in a dose-dependent manner. The combination of theophylline and cisplatin resulted in a further dramatic reduction in Bcl-2, under-scoring the pronounced synergy of these two drugs. These observations suggest that suppression of Bcl-2 expression may play an important role in mediating the synergistic effect of cisplatin and theophylline on induction of apoptosis in ovarian cancer cells.

Antineoplastic Agents↗
PubMed1999

Role of factor VIII C2 domain in factor VIII binding to factor Xa.

Factor VIII (FVIII) is activated by proteolytic cleavages with thrombin and factor Xa (FXa) in the intrinsic blood coagulation pathway. The anti-C2 monoclonal antibody ESH8, which recognizes residues 2248-2285 and does not inhibit FVIII binding to von Willebrand factor or phospholipid, inhibited FVIII activation by FXa in a clotting assay. Furthermore, analysis by SDS-polyacrylamide gel electrophoresis showed that ESH8 inhibited FXa cleavage in the presence or absence of phospholipid. The light chain (LCh) fragments (both 80 and 72 kDa) and the recombinant C2 domain dose-dependently bound to immobilized anhydro-FXa, a catalytically inactive derivative of FXa in which dehydroalanine replaces the active-site serine. The affinity (K(d)) values for the 80- and 72-kDa LCh fragments and the C2 domain were 55, 51, and 560 nM, respectively. The heavy chain of FVIII did not bind to anhydro-FXa. Similarly, competitive assays using overlapping synthetic peptides corresponding to ESH8 epitopes (residues 2248-2285) demonstrated that a peptide designated EP-2 (residues 2253-2270; TSMYVKEFLISSSQDGHQ) inhibited the binding of the C2 domain or the 72-kDa LCh to anhydro-FXa by more than 95 and 84%, respectively. Our results provide the first evidence for a direct role of the C2 domain in the association between FVIII and FXa.

Amino Acid Sequence↗
PubMed1999

Effect of 12-O-tetradecanoyl-phorbol ester and incisional wounding on neuropsin mRNA and its protein expression in murine skin.

The expression of neuropsin mRNA in vivo in mouse skin was examined by in situ hybridization and Northern blotting under stimulated conditions. Two kinds of epidermal stimuli, a topical application of a chemical tumor promoter and incisional wounding, were used. A single topical application of 12-O-tetradecanoyl-phorbol 13-acetate induced epidermal hyperplasia and simultaneously induced an extensive increase in neuropsin mRNA in the suprabasal cells. A full-thickness skin incision also induced a profound increase in neuropsin mRNA in the suprabasal cells surrounding the wound but not in actively proliferating basal cells. The increases in neuropsin mRNA occurred rather late and were limited to the site of drug application or around the incision. Interestingly, neuropsin mRNA was not expressed in the epithelial tongue migrating toward the wound during re-epithelialization. Thus, neuropsin might participate in accelerated epidermal differentiation rather than in the proliferation or migration of keratinocytes in the wound.

Animals↗
PubMed1999

Crosstalk Among Multiple Signaling Pathways Controlling Ovarian Cell Death.

Ovarian cell death is an essential process for the homeostasis of ovarian function in human and other mammalian species. It ensures the selection of the dominant follicle and the demise of excess follicles. In turn, this process minimizes the possibility of multiple embryo development during pregnancy and assures the development of few but healthy embryos. Degeneration of the old corpora lutea in each estrous/menstrual cycle by programmed cell death is essential to maintain the normal cyclicity of ovarian steroidogenesis. Although there are multiple pathways that can determine cell death or survival, crosstalk among endocrine, paracrine and autocrine factors, as well as among protooncogenes, tumor suppressor genes, survival genes and death genes, plays an important role in determining the fate of ovarian somatic and germ cells. The establishment of immortalized rat and human steroidogenic granulosa cell lines and the investigation of pure populations of primary granulosa cells allows systematic studies of the mechanisms that control steroidogenesis and apoptosis of granulosa cells. These cells are the most abundant type of somatic follicular cell. Moreover, crosstalk between p53 and extracellular matrix components such as laminin, fibronectin and basic fibroblast growth factor, between cAMP- and p53-generated signals and between steroid hormones and Bcl-2, can explain some of the fine tuning that controls ovarian steroidogenesis and apoptosis. Further study of the mechanisms of ovarian cell death will lead to a better understanding of the processes involved and permit the formulation of novel strategies for the treatment of ovarian malfunctions, such as polycystic ovarian syndrome and ovarian cancer.

Journal Article↗
PubMed1999

Regulation of keratin 9 in nonpalmoplantar keratinocytes by palmoplantar fibroblasts through epithelial-mesenchymal interactions.

Palms and soles differ from other body sites in terms of clinical and histologic appearance, response to mechanical stress, and the distribution of keratin 9. Because keratin 9 is exclusively expressed in the palmoplantar suprabasal keratinocyte layers, it is considered a differentiation marker of palms and soles. We studied palmoplantar mesenchymal influences on keratin 9 induction in nonpalmoplantar epidermis. Although palmoplantar keratinocytes when cultured alone continued to express keratin 9 mRNA in 12 (100%) of 12 cultures, nonpalmoplantar keratinocytes did not express it in 16 of 17 cultures. Although nonpalmoplantar keratinocytes did not express keratin 9 mRNA when cultured with nonpalmoplantar fibroblasts, they did express it within 2 h in cocultures with palmoplantar fibroblasts derived from papillary dermis. Grafting of these coculture sheets on severe combined immunodeficient mice resulted in an epidermis, which histologically showed hyperkeratosis and acanthosis and immunohistochemically expressed keratin 9. Furthermore, pure epidermal sheets from nonpalmoplantar skin grafted on the human sole wounds due to burn, injury, and the resection of acral lentiginous melanoma, demonstrated adoption of palmoplantar phenotype and expressed keratin 9. Our report indicates extrinsic keratin 9 regulation by signals from dermal fibroblasts. This is also the first to suggest the possibility of treating palmoplantar wounds with nonpalmoplantar epidermis, which is much easier to obtain and harvest.

Animals↗
PubMed1999

Role of ovarian theca and granulosa cell interaction in hormone productionand cell growth during the bovine follicular maturation process.

We have investigated the possible role of theca and granulosa cell interaction in the control of the hormone-producing activity and growth of granulosa and theca cells during bovine ovarian follicular development, using a coculture system in which granulosa and theca cells were grown on opposite sides of a collagen membrane. When follicular cells were isolated from small follicles (3-5 mm), theca cells reduced estradiol, progesterone, and inhibin production by granulosa cells to 14 +/- 5%, 64 +/- 6%, and 27 +/- 4%, respectively, of the production by granulosa cells cultured alone. On the other hand, when the cells were isolated from large follicles (15-18 mm), theca cells increased these levels to 253 +/- 34%, 156 +/- 24%, and 287 +/- 45%, respectively. Theca cells did not affect the growth of granulosa cells. Androstenedione production by theca cells was augmented by granulosa cells to 861 +/- 190% (in small follicles) and 1298 +/- 414% (in large follicles), respectively. The growth of theca cells was also augmented by granulosa cells (small follicle, 210 +/- 43%, and large follicle, 194 +/- 24%, respectively). These results indicate that theca cells secrete factor(s) inhibiting the differentiation of immature while promoting that of matured granulosa cells; they also suggest that granulosa cells secrete factor(s) promoting both the differentiation and growth of theca cells throughout the follicular maturation process.

Androstenedione↗
PubMed1998

Effects of a time-varying strong magnetic field on transient increase in cytosolic free Ca2+ induced by bradykinin in cultured bovine adrenal chromaffin cells.

We tested the effects of exposure to a time-varying magnetic field changing between 0.07 and 1.7 T at an interval of 3 s on transient increase in intracellular Ca2+ stimulated by bradykinin in bovine adrenal chromaffin cells. Addition of bradykinin induced the increase in intracellular Ca2+ within a few minutes. The exposure to the magnetic field perfectly suppressed the increase in intracellular Ca2+ in Ca2+-free medium. The inhibition occurred for 15 min when the maximum magnetic flux density was more than 1.4 T. These results suggest that the exposure inhibits Ca2+ release from intracellular Ca2+ stores.

Animals↗
PubMed1998

Taurin-conjugated ursodeoxycholic acid has a reversible inhibitory effect on human keratinocyte growth.

Tauroursodeoxycholic acid (TUDC) is one of the most hydrophilic taurin conjugated bile acids. TUDC has a suppressive effect on DNA synthesis in primary cultured rat hepatocytes. In this study, we investigated the growth inhibitory effect of TUDC on cultured human keratinocytes. TUDC suppressed the proliferation of keratinocytes in a dose dependent fashion, as measured by both cell counts and 5-bromo-2'-deoxyuridine (BrdU) uptake. Keratinocytes reproliferated and reached almost the same cell number as control after removal of TUDC from the medium. TUDC (1 mM) had no effect on the cell viability, as measured by the dye exclusion test. Epidermal sheets stratified in the presence of TUDC appeared thinner than those stratified without TUDC. These results suggest that TUDC has a reversible growth suppressive effect on human keratinocytes through the mechanism other than cytotoxicity and would be applicable for the treatment of hyperproliferative skin disorders such as psoriasis.

Animals↗
PubMed1998

Expression of exon 5 deleted estrogen receptor variant messenger RNA in human uterine myometrium and leiomyoma.

To examine the relationship between uterine leiomyoma, an estrogen-dependent tumor and its estrogen receptor, the relative amounts of wild type estrogen receptor (WT) mRNA and exon 5 deleted estrogen receptor variant (D5-ER) mRNA to G3PDH mRNA were examined in human uterine myometrium and leiomyoma specimens obtained from 46 patients in 3 age groups (group A: 41-45 years old, group B: 46-50 years old, group C: 51-54 years old) using a quantitative reverse transcription polymerase chain reaction method (RT-PCR). D5-ER mRNA was co-expressed with WT mRNA in all myometrium and leiomyoma specimens. In myometrium, the relative amount of WT decreased with aging, but in leiomyoma, it was high in group B. The relative amount of D5-ER mRNA and the ratio of D5-ER mRNA to WT mRNA (D5/WT ratio) were significantly higher in group C in both myometrium and leiomyoma. The percentage of the patients whose D5/WT ratio was higher in leiomyoma than in myometrium (L/M ratio>1.0) increased with age. These findings suggest that D5-ER increases to supplement the decreasine in WT in uterine tissues toward menopause and that D5-ER plays a more active role in leiomyoma than in myometrium during the perimenopausal period.

Adult↗
PubMed1998

Growth patterns and genetic changes of colorectal carcinoma.

BACKGROUND: Recent Japanese studies have shown that histogenesis of small colorectal carcinomas can be divided into two groups: polypoid growth arising from polypoid neoplasia, and nonpolypoid growth arising from flat or depressed neoplasia. This classification should be verified with genetic as well as morphologic characteristics. SUBJECTS AND METHODS: In order to classify our subject into polypoid growth and nonpolypoid growth types both histologically and endoscopically, we selected 42 colorectal carcinomas < 2 cm in size (35 submucosal and seven more advanced). Clinicopathological findings, presence or absence of Ki-ras gene mutation and overexpression of p53 protein were compared between the two types. RESULTS: Histologically, the cases were divided into 27 of the polypoid growth type and 15 of the nonpolypoid growth type. None of the nonpolypoid growth cases contained adenomatous remnant, wheras this was found in 75% of the polypoid growth cases. No Ki-ras mutation was observed in any of the nonpolypoid growth cases, although it appeared in 44% of the polypoid growth cases. Regarding the overexpression of p53 protein, no significant difference was observed between the two types. The histological and the colonoscopic polypoid growth-nonpolypoid growth classifications correlated well with each other (agreement rate 98%), except for one lesion, which was classified as polypoid growth type endoscopically but as nonpolypoid growth type histologically. CONCLUSIONS: The histologically defined polypoid growth-nonpolypoid growth classification may indicate a difference in pathway of colorectal carcinogenesis. Also, colonoscopic polypoid growth-nonpolypoid growth classification is available for preoperative estimation of the genetic characteristics of small carcinomas.

Adenoma↗
PubMed1998

Diagnostic findings in endoscopic screening of superficial colorectal neoplasia: results from a prospective study.

BACKGROUND: A prospective study was carried out to clarify the efficacy of an endoscopic screening program for detecting superficial colorectal neoplasias by color changes such as faint redness or discoloration, which have been described as a key finding of these lesions in the literature. METHODS: We enrolled 716 consecutive cases in this study, but more than half of them did not reveal any abnormalities colonoscopically. RESULTS: Of the 716 cases, 48 (7%) were examined by magnifying colonoscopy with a dye spraying technique, following the detection of superficial color changes. Sixteen neoplastic lesions (in 16 cases) were detected among the 48 cases and the detection rate was calculated as 2.2% (16/716) in the total number of cases and 33% (16/48) in those showing color abnormalities. Histologically, all of the 16 were adenomas. These neoplastic lesions were most frequent (52%; 11/21) in those showing faint redness in an oval shape, whereas 14 (94%) of the 15 lesions were non-specific in those showing faint redness with unclear margin. CONCLUSIONS: These results may confirm the diagnostic utility of color abnormality, particularly faint redness in an oval shape, for endoscopic screening of superficial colorectal neoplasias.

Adenoma↗
PubMed1998

Endoscope-assisted transaxillary removal of glandular tissue in gynecomastia.

Gynecomastia is a condition commonly associated with puberty. An endoscope-assisted transaxillary procedure was used to treat a patient with this condition. An endoscope system was inserted into a 4-cm skin incision in the axilla, and the glands and adjacent fat were removed en bloc. The resulting scar in the axilla was small and inconspicuous, and the postoperative breast contour satisfied the patient. The endoscopic system provided a useful transaxillary approach. These results show that this method appears to be the most suitable one for surgical management of gynecomastia.

Adolescent↗
PubMed1998

Breast reconstruction after mastectomy without additional scarring: application of endoscopic latissimus dorsi muscle harvest.

Breast reconstruction with the latissimus dorsi muscle flap combined with a saline-filled implant was performed. Using an endoscope, additional operative scarring due to muscle harvesting was avoided. The operative techniques were easier than usual endoscopic surgery because most of the procedures were performed under direct vision. The procedures are presented in this article.

Adult↗