FIBER TYPE DIFFERENTIATION AND MYOSIN EXPRESSION IN REGENERATING RAT MUSCLES

The relation between fiber type differentiation and the expression of slow and fast myosin isoforms was examined in regenerating rat muscles after injection of a myotoxic agent, bupivacaine. The histochemical myosin ATPase reaction for fiber typing demonstrated that immature type 2C fibers differentiated into type 1, 2A and 2B fibers. Slow and fast myosin isoforms were demonstrated immunohistochemically using antibodies raised against myosins extracted from the slow-twitch soleus and fast-twitch tensor fasciae latae muscles of mature guinea pigs (anti-SOL, anti-TFL). The results showed that immature type 2C fibers destined to differentiate into type 1 fibers first reacted with anti-TFL only, and later reacted with both anti-TFL and anti-SOL, whereas those destined to differentiate into type 2A and 2B fibers reacted with anti-TFL only throughout regeneration. The significance of the myosin isoforms that react with anti-TFL in immature type 2C fibers was discussed. ACTA PATHOL. JPN. 37: 1537-1547, 1987.     

Simplified determination of serum cholesterol sulfate by gas-liquid chromatography combined with cyclohexylsilane-bonded phase column purification

Summary A new gas-liquid chromatographic (GLC) determination of cholesterol sulfate (CS) and dehydroepiandrosterone sulfate (DHEAS) for a biochemical diagnosis of recessive X-linked ichthyosis (RXLI) is described. Although the GLC method for determination of CS is known to be more sensitive than the thin layer chromatographic (TLC) method, the former method has not been widely employed because of its complicated pre-purification steps. The present method allows us to measure the serum levels of CS and DHEAS without tedious purification steps such as multiple conventional column chromatography and preparative thin layer chromatography. Sulfated steroids are rapidly purified with a commercially available mini disposable cyclohexylsilane-bonded phase (CH) column, CH BOND ELUT, and the purified steroids after desulfation are converted to water-resistant tert-butyldimethylsilyl ether derivatives for the GLC analysis on dual 2 m glass columns packed with 2% XE-60 on Chromosorb W.By the present method, serum CS concentrations in RXLI patients were shown to be about 10 times higher than those in patients with ichthyosis vulgaris, carriers of RXLI, and healthy subjects. This method is more suitable not only for a biochemical diagnosis of RXLI but also for studies on the metabolism of sulfated steroids than the previous time-consuming GLC methods.     

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.     

Dynamic MRI of the gallbladder lesions: Differentiation of benign from malignant

Forty-nine pathologically proven gallbladder lesions were evaluated in 45 patients using dynamic MRI with a spoiled gradient pulse sequence (SPGR), to access the ability of this technique to differentiate benign from malignant gallbladder lesions. The studies were reviewed retrospectively. Signal intensity of the lesions were measured. Twenty-one malignant and 28 benign lesions were classified into three categories: polypoid, diffuse wall thickening, and exophytic. Early and delayed enhancement patterns were evaluated. For the polypoid masses, malignant lesions (n = 9) demonstrated early and prolonged enhancements, whereas benign lesions (n = 14) had early enhancement with subsequent washout (P < .05). For diffuse gallbladder wall thickening, malignant lesions (n = 6) demonstrated early and prolonged enhancement and benign lesions (n = 14) showed relatively slow, prolonged enhancement (P < .05). The exophytic masses (n = 6) all were malignant and demonstrated early and prolonged enhancement. Dynamic MRI can help differentiate benign from malignant gallbladder lesions.     

Use of latissimus dorsi flap for reconstruction with prostheses after tumor resection

Five latissimus dorsi musculocutaneous flaps (LD flap) were used for reconstruction with prostheses after resection of tumors between 1984 and 1991 in our hospital. Bony structures were reconstructed with prostheses and in three cases autoclaved autobone grafts were also needed. The prostheses and adjacent grafts were then wrapped by the LD flaps. Tumor sites included one humerus, two thighs, and two knees. All but one case healed primarily. The sole case of infection was successfully treated with debridement and irrigation. Due to the LD flaps' plentiful blood supply, we believe infection of the prosthetics can be avoided and good clinical results can be achieved using the flap with autoclaved autograft prosthetic composite reconstruction. © 1994 Wiley-Liss, Inc.