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Biomedical subjects

K Hidaka

Publications and source records attributed to K Hidaka.

151 records · Page 9Linked to original sources
PubMed1978

Differential control of synergistic effect with polyene macrolide antibiotics upon Chinese hamster cells in vitro.

An amphotericin B-resistant cell (AMBR-1), which was isolated from aneuploid Chinese hamster cells (V79), was found to show much higher resistance than the parent V79 cells to other polyene antibiotics, such as pentamycin and filipin. To obtain the 50 to 60% inhibition of the control protein synthesis activity by a synergistic combination of fusidic acid and amphotericin B, 50 microgram fusidic acid per ml were combined with 10 microgram amphotericin B in V79 cells, whereas in AMBR cells 50 microgram fusidic acid per ml were combined with 100 microgram polyene antibiotic per ml. Bleomycin (10 microgram/ml), which alone did not affect cellular DNA synthesis, inhibited DNA synthesis of V79 cells by more than 90% of the control activity when combined with only 1 microgram pentamycin per ml, whereas a similar extent of inhibition in AMBR cells was observed by combination with more than 5 microgram pentamycin per ml.

Amphotericin B↗
PubMedDate not supplied

Three-dimensional structure of the rat pancreatic duct in normal and inflammated pancreas.

We observed the corrosion casts of the Wistar rats' pancreatic ducts with scanning electron microscopy (SEM), and their conventionally fixed pancreatic tissue with SEM and transmission electron microscopy (TEM). These findings revealed the following facts about the three-dimensional structure of pancreatic duct. (1) The interlobular and intralobular ducts branch like a tree, and the intercalated ducts wind and fork into two branches, although parts of the intercalated ducts anastomose with each other. The intercellular secretory canaliculi extend from the central lumina, which run straight through the center of the acini, finally approaching close to the basement membranes of acini. (2) The lumina of pancreatic ducts (i.e., the interlobular up to the intercalated ducts) are cylindric and have smooth surfaces. The luminal surface of each epithelial cell, however, is decorated by numerous microvilli and a single cilium. The length of the latter tends to be short in proportion to the diameter of pancreatic duct. Moreover the epithelial cell surfaces, which border each central lumen, have various densities of microvilli. (3) The intraductal cilium core is provided with nine microtubules, which is different from the number of microtubules encountered within the cilium core of uterine tube or bronchial epithelium. The number of microtubules in the cross-sectioned intraductal cilia decreases toward the distal portion of cilia. SEM and TEM observations on WBN/Kob rats' pancreatic ducts suggest that increased pancreatic ductal pressure causes the helical shape of the pancreatic ductal lumen. Such a helical form might also be caused by the protrusion of epithelial cell boundaries into their lumen and the hypertrophy and hyperplasia of epithelial cells, thus leading to the formation of numerous depressions equipped with elongated cilia.

Animals↗
PubMedDate not supplied

Evaluation of a new heparin bonding process in prolonged extracorporeal membrane oxygenation.

A novel heparin bonding method has been developed for in situ surface modification using ozone oxidation, and evaluated in vitro and in vivo during prolonged extracorporeal membrane oxygenation (ECMO) experiments. The ECMO system consisted of a Capiox hollow fiber membrane oxygenator (MO; Terumo Corp., Tokyo, Japan) with an integral heat exchanger, a Capiox centrifugal pump (CP), and an extracorporeal circuit. The blood contacting surfaces of the system were completely modified using the heparin bonding process, and evaluated in a chronic sheep model for extended period of time, ranging from 96 to 168 hr, under minimal systemic heparinization. The heparin bonded surface was able to maintain high levels of heparin bioactivity, and showed improved blood compatibility in in vitro epifluorescent video microscopy experiments by suppressing platelet adhesion/activation and complement activation. For the ECMO experiments, extracorporeal blood flow was maintained at 3 L/min and the activated clotting time was maintained at 150 sec. There was no significant change in the gas transfer capability or mean pressure drop across the MO over experimental times of up to 168 hr. Platelet count and other coagulation parameters remained stable within the physiologic range throughout the experiment. There were no detectable thrombi in the CP, tubing, or connectors in the test circuit. Local thrombus formation was noted in a stagnant area of the MO, although this did not interfere with its function or lead to any significant embolization. Based on these results, the heparin bonded ECMO system appears to be a safe and effective device for prolonged extracorporeal circulation under minimal systemic heparinization.

Animals↗
PubMedDate not supplied

Correlation between CA19-9 production in vitro and histological grades of differentiation in vivo in clones isolated from a human pancreatic cancer cell line (SUIT-2).

The production of carcino-embryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) were investigated in 28 clones isolated from a human pancreatic cancer cell line (SUIT-2) and related to in vitro morphology of the clones and in vivo tumorigenicity. Clones of fusiform and polygonal cells could be morphologically distinguished in confluent cultures. There was no significant difference in CEA production between fusiform-cell clones (2.10 +/- 2.70 ng/L x 10(6) per 24 h) and polygonal-cell clones (6.01 +/- 7.30 ng/L x 10(6) per 24 h), but polygonal-cell clones had higher production of CA19-9 (1176.1 +/- 1628.4 U/L x 10(6) per 24 h) than fusiform (6.0 +/- 7.3 U/L x 10(6) per 24 h; P < 0.01). Production of CA19-9 in vitro correlated with the histological grade of differentiation in vivo in nude mice (r = 0.73, P < 0.001), but CEA production did not. The polygonal-cell clones developed well-differentiated carcinomas in vivo and produced significantly more CA19-9 (P < 0.001) than fusiform-cell clones, which generally developed into poorly differentiated tubular adenocarcinomas in vivo. This cell line may provide an appropriate system for further studies of the biology and therapy of pancreatic cancer.

Adenocarcinoma↗