Biomedical subjects

H Miyoshi

Publications and source records attributed to H Miyoshi.

311 records · Page 18Linked to original sources

PubMedDate not supplied

Long-term culture of fetal liver cells using a three-dimensional porous polymer substrate.

To develop a bioartificial liver, long-term culture of fetal liver cells over a month's time was performed under three different culture conditions, i.e., stationary cultures and shaken-flask cultures, both by using a substratum made of porous polyvinyl formal (PVF) resin and conventional monolayer dish cultures as controls. Time course changes in cell numbers and albumin secretion were evaluated in cultures using Williams' E medium (WE) or minimum essential medium alpha (aMEM) supplemented with serum and hormones. In the WE medium, the numbers of fetal liver cells in all culture conditions gradually decreased with time, and albumin secretion rates rapidly decreased. In the stationary cultures using PVF, however, a significant increase in albumin secretion was observed after two weeks of culture. When cells were cultured in aMEM, the fetal liver cells exhibited sufficient proliferation in stationary and monolayer cultures, although albumin secretion rates per single cell were lower than those in WE. On the basis of these results, another series of culture experiments were performed, in which aMEM was used for the first 10 days to encourage cell proliferation, and the medium was changed to WE afterward. In these cultures, albumin secretion rates in the stationary cultures dramatically increased after the medium exchanges and were maintained at these high levels throughout the remaining culture period.

Animals↗

PubMedDate not supplied

New type of matrix support for bone marrow cell cultures: in vitro culture and in vivo transplantation experiments.

A new type of bone marrow cell culture system was developed by using a highly porous substrate matrix, i.e., porous polyvinyl formal (PVF) resin. Murine bone marrow (BM) cells were cultured without the use of exogenous growth factors in a three-dimensional matrix support made of collagen coated porous PVF resin. To examine the optimal conditions for highest stromal cell density, short-term and long-term in vitro culture experiments using PVF were performed. In the short-term culture experiments, it was found that cubes of PVF (10 x 10 x 2 mm and 130 microm in pore size) coated with type I collagen with a seeding density of 2x10(7) BM cells offered the most appropriate culture conditions. In the long-term cultures, BM cells in PVF maintained their viability for up to 6 weeks. In another series of re-inoculation experiments, freshly isolated BM cells were inoculated onto the already developed stromal layer. In this study, a higher cell density of the stromal layer was obtained in the PVF culture compared with those in the control dish culture. Based upon the results of in vitro experiments, in vivo transplantation studies were also performed. Histologic examinations of the subcutaneously transplanted PVF with stroma revealed host derived hematopoiesis inside the PVF matrix. Moreover, survival of approximately 15% of the transplanted BM cells that were cultured in PVF were confirmed in X-ray irradiated recipients. From these results, it is suggested that PVF resin is a promising three-dimensional substrate for BM cell culture and that it can maintain hematopoietic stem cells or progenitor cells after transplantation.

Animals↗

PubMedDate not supplied

Prospective study of the detection of anomalous connections of pancreatobiliary ducts during routine medical examinations.

BACKGROUND/AIMS: It is important to achieve detection of of anomalous connections of the pancreatobiliary ducts (ACPBD), because this condition often leads to pancreatobiliary disease. The present prospective investigation focused on revealing the incidence of ACPBD in asymptomatic individuals undergoing medical checkups. MATERIAL AND METHODS: Extracorporeal ultrasonography (US) was performed on all asymptomatic individuals undergoing medical checkups. Identification by abdominal ultrasonography of 3 mm or more gallbladder wall thickening, or 10 mm or more dilatation of the bile duct were considered indicative of ACPBD and endoscopic ultrasonography (EUS) was carried out in selected cases. Endoscopic retrograde cholangiopancreatography (ERCP) was then performed to confirm the existence of ACPBD. RESULTS: The overall incidence of ACPBD was 0.03% (9/27,076 subjects). ACPBD was found in 23% of cases with bile duct dilatation, and in 2.9% with gallbladder wall thickening. CONCLUSION: ACPBD was not as rare a disease as expected. For early detection of ACPBD, identification by abdominal ultrasonography of gallbladder wall thickening or dilatation of the bile duct are indicative. Patients who are suspected of having this abnormality should then undergo EUS. The final diagnosis should then be made by ERCP.

Adult↗

PubMedDate not supplied

Ras gene point mutations in gallbladder lesions associated with anomalous connection of pancreatobiliary ducts.

BACKGROUND/AIMS: The present study was undertaken to investigate possible changes in the K-ras oncogene in patients with gallbladder lesions (carcinoma, adenoma or hyperplasia) in relation to the presence or absence of an anomalous connection of pancreatobiliary ducts (ACPBD). METHODOLOGY: Gallbladder specimens were obtained from 44 patients with lesions that were either with or without ACPBD, and DNA samples were analyzed using PCR-SSCP. Point mutations in codons 12, 13 and 61 were analyzed by direct sequencing methods with oligonucleotide primers. RESULTS: The K-ras codon 12 was detected in 83.3% (5/6) of carcinomas the one adenoma tested and in 35.7% (5/14) of hyperplastic lesions with ACPBD, as opposed to only 36.4% (4/11) of carcinomas without ACPBD. The one case of gallbladder adenoma and 11 cases of normal gallbladder without ACPBD studied demonstrated no point mutations in the K-ras oncogene. CONCLUSIONS: Alteration of the K-ras oncogene appears to be involved in the early stages of gallbladder carcinogenesis when in association with ACPBD. The results further suggest that hyperplasia in cases with ACPBD may be a significant pre-cancerous lesion.

Adenocarcinoma↗

PubMedDate not supplied

Mucin-producing tumor of the pancreas--intraluminal ultrasonography.

BACKGROUND/AIMS: Many patients with mucin-producing pancreatic tumor, characterized by dilatation of the pancreatic duct, are diagnosed by conventional ultrasonography in a mass ultrasonographic survey in Japan. It is a necessary and reliable method for making a precise diagnosis and for deciding on the treatment approach. Endoscopic ultrasonography (EUS) is appreciated as a useful method for precise diagnosis of pancreatic tumors. Intraductal ultrasonography (IDUS) is expected to be a new modality for the more detailed diagnosis of pancreatic tumors. METHODOLOGY: Endoscopic ultrasonography and intraductal ultrasonography were performed in 23 patients with mucin-producing pancreatic tumor. The differences in ultrasonographic findings between benign and malignant tumors were studied. RESULTS: Ultrasonographic findings of mucin-producing pancreatic tumor revealed by EUS and IDUS were: cystic lesion, mural nodule in the cystic lesion, wall thickness of the cyst, mucus echoes, and solid tumor with a mixed echo pattern. Seven out of 11 patients with mural nodule were diagnosed as carcinomas and another 4 patients had adenoma. Seven of 8 patients with mucus echoes were diagnosed as carcinoma. Three of 4 patients with solid tumor were diagnosed as invasive carcinoma. The ultrasonographic findings suggesting malignancy were: mural nodule, irregular wall thickness, mucus echoes, and solid tumor with a mixed pattern. Solid tumor indicated invasive carcinoma exclusively. CONCLUSIONS: Intraluminal ultrasonography, EUS and IDUS are very useful in making a differential diagnosis between benign and malignant tumors in mucin-producing pancreatic tumors.

Adenocarcinoma, Mucinous↗