In Vitro Evaluation of Platelet/Biomaterial Interactions in an Epifluorescent Video Microscopy Combined with a Parallel Plate Flow Cell

Abstract: Suitable evaluation systems are critical for ranking various biomaterials in order to develop a method to design and synthesize nonthrombogenic biomaterials. We have recently developed an in vitro test system to evaluate platelet/biomaterial interactions in whole blood. The system consists of a parallel plate flow cell and epifluorescent video microscopy (EVM). A glass coverslip coated with a polymer was incorporated into the flow cell, and blood was perfused using a syringe pump via a polymer–coated PVC tubing connected to the flow cell. Whole human blood was anticoagulated with heparin (2 U/ml), and the platelets were labeled with the fluorescent dye mepacrine (5 μM). This system permitted real–time and dynamic observations of platelet/biomaterial interactions in whole blood under a defined flow condition. In order to evaluate the feasibility of this system, two different segmented polyether–polyurethanes (SPEUs), PU–PTMG(650) and PU–PTMG(2000), were chosen as test polymers. Surface characteristics verified with electron spectroscopy for chemical analysis (ESCA) and contact angle measurements showed similar results in both SPEUs. Blood was perfused at a wall shear rate of 200 s^–1 for 20 min. Excitation light was applied for 2 s at 1 min intervals. The real–time image was then analyzed at each time point for the percentage of surface area of platelet coverage. Plasma β–thromboglobulin (β–TG) levels were also measured before and after each run. PU–PTMG(650) showed a significantly higher number of adhered platelets than PU–PTMG(2000) at each time point. β–TG levels of PU–PTMG(650) were also higher than those of PU–PTMG(2000), which is comparable to the results of EVM. Thus, this EVM system has been proven to be an excellent and highly sensitive in vitro analytical method for evaluating platelet/biomaterial interactions.     

Surgical treatment of myasthenia gravis associated with Graves's disease]

During past 30 years, we experienced 253 patients who underwent surgery for myasthenia gravis. Among these patients, 9 were associated with Graves' disease. No patients had thymoma. Five patients underwent thymectomy after they had become euthyroid by medical treatment, though four patients required subtotal thyroidectomy before thymectomy. One patient developed myasthenic crisis following thyroidectomy and was treated with respirator for 5 days. But thymectomy was performed without myasthenic crisis in these four patients between 25 days and 60 days after thyroidectomy. They have been doing well and no see-saw phenomenon was presented. Thymectomy is safe and effective even in the patients with Graves's disease, and we recommend to perform it after they become euthyroid by medical or surgical treatment.     

Significance of the BTA Test in Bladder Cancer: A Multicenter Trial

Background :
The BTA test is a latex agglutination assay for the qualitative detection in the urine of analytes that are associated with bladder tumor. We compared the results of the BTA test with those of voided urine cytology (VUC) in patients with bladder cancer.
Methods :
A multicenter trial was performed at 6 institutions. A total of 132 patients with histologically diagnosed bladder cancer were enrolled. Urine samples were split for BTA and VUC testing.
Results :
The sensitivities of the BTA test and VUC were 57.6% and 37.9%, respectively; this difference was significant ( P < 0.001). The BTA test had much higher sensitivity for small, solitary, superficial tumors than did VUC.
Conclusion :
The BTA test is simple to perform, gives rapid results, and is far more sensitive than VUC for detection of bladder cancer. The BTA test has the potential to become an additional tool for detecting bladder cancer.     

Determination of vitamin B6 derivatives in foods and biological materials by reversed-phase HPLC

Through use of a simplified analyzing system, seven vitamin B6 derivatives were determined with a satisfactory sensitivity and precision. This system consisted of a single reversed-phase ODS column with a fluorescence detector employing an isocratic solvent system. Each vitamin B6 derivative in some foods and biological materials was determined, based on the measurement of the integrated peak area. The data obtained by this method were compared with those obtained from a bioassay by Saccharomyces uvarum ATCC 9080, after acid hydrolysis of these materials.     

Experimental study of vagotomy for prevention of stress ulcer after hepatectomy of cirrhotic livers. Its influence on hepatic regeneration

We experimentally studied the influence of vagotomy on hepatic regeneration in rats after hepatectomy of cirrhotic livers. In animals that underwent hepatectomy plus vagotomy the reduction in gastric pH was suppressed, but gastric mucosal blood flow was less than that in control animals that received hepatectomy alone. The suppression of 3H-thymidine uptake percentage and thymidine kinase activity after hepatectomy was more marked in animals treated with hepatectomy plus vagotomy than in controls treated with hepatectomy alone. Hepatic DNA level tended to be lower in animals treated with hepatectomy plus vagotomy than in controls. In animals treated with hepatectomy plus vagotomy, the peak level of the mitotic index was lower and the hepatic regeneration rate was evidently suppressed. These results suggest that it is not appropriate to apply vagotomy, during hepatectomy of cirrhotic livers, for the prevention of postoperative stress ulcer because it causes a marked reduction in gastric mucosal blood flow and suppresses hepatic regeneration.