Effect of a prostaglandin EP4 receptor agonist on early fixation of hydroxyapatite/titanium composite- and titanium-coated rough-surfaced implants in ovariectomized rats

The agonist of the prostaglandin EP4 receptor can increase bone density in osteoporosis. Using ovariectomized (OVX) and sham-operated (SO) rats, the effects of the EP4 receptor agonist, ONO-4819, and hydroxyapatite (HA) on implant-bone fixation in implants with a rough surface were investigated. Female Wistar rats (12 weeks old) were divided into either SO or bilateral OVX groups. Twenty four weeks later, either hydroxyapatite/titanium (HA/Ti) composite-coated or Ti-coated implants were implanted into the femora, and the animals were treated with either ONO-4819 or saline for 4 weeks. The fixation strength of the HA/Ti-coated implants was higher than that of the Ti-coated implants in the saline-treated OVX rats. In the OVX rats, ONO-4819 enhanced fixation of the rough Ti-coated implants to levels similar to that of HA/Ti-coated implants. These data suggest that a combination of treatment with an EP4 receptor agonist and a rough-surfaced implant might be useful in increasing the early fixation of cement-less arthroplasty, particularly in elderly patients with osteoporosis.

Bronchovascular cuff formation and lung lymph flow in edema formation of anesthetized sheep

The relationship between bronchovascular cuff formation and lung lymph flow in hydrostatic edema was evaluated. After a balloon was inserted into the left atrium to increase left atrial pressure for 5 hrs, peripheral lung tissues were resected for analysis of the wet-dry ratio and cuff formation. The degree of cuff formation was expressed as the cuff ratio (outer diameter of cuff/outer diameter of microvessel or airway) in three size categories: 80-200, 200-400, and 400-750 microm in diameter. The amount of excess lung lymph (Ex LL) for 5 hrs was calculated from the recorded data for the whole lymph flow wave. The wet-dry ratio showed a significant correlation with ALAP and lung lymph flow increased significantly (flow rate, 0.67 +/- 0.46 ml/min (mean +/- SD); Ex LL, 56.4 +/- 47.6 ml). Cuff formation was found at all levels of the bronchovascular tree, with a larger cuff ratio (> 1.3) observed at arteries and veins of 80-200 microm in diameter, but a significant correlation with Ex LL was found only for arteries of 80-200 microm. Fluid accumulation in lung interstitium first occurred at smaller extra-alveolar arteries even under mild hydrostatic pressure elevation with a significant increase in lymph flow.

Ezetimibe improves postprandial hyperlipidaemia in patients with type IIb hyperlipidaemia

BACKGROUND

Postprandial hyperlipidaemia is known to be a high-risk factor for atherosclerotic disease because of rapid and lasting accumulations of triglyceride-rich lipoproteins and remnants. The Niemann-Pick C1-Like 1 (NPC1L1) protein acts as an intestinal cholesterol transporter and ezetimibe, which inhibits NPC1L1, has been used in patients with hypercholesterolaemia. We investigated effects of ezetimibe on fasting lipid and lipoprotein profiles and postprandial hyperlipidaemia in patients with type IIb hyperlipidaemia.

MATERIALS AND METHODS

Ezetimibe 10 mg per day was administered in ten patients with type IIb hyperlipidaemia for 2 months, and lipid and lipoprotein profiles were examined during fasting and after an oral fat loading (OFL) test.

RESULTS

In the fasting state, ezetimibe significantly decreased not only total cholesterol, low density lipoprotein (LDL)-cholesterol and apolipoproteinB-100 (apoB-100) levels but triglycerides (TG), apoB-48 and remnant lipoprotein cholesterol (RemL-C) levels. High performance liquid chromatography analysis showed that ezetimibe decreased cholesterol and TG levels in the very low density lipoprotein (VLDL) and LDL size ranges as well as apoB-100 levels, suggesting a decrease in numbers of VLDL and LDL particles. After OFL, ezetimibe decreased the area under the curve for TG, apoB-48 and RemL-C. Ezetimibe decreased postprandial elevations of cholesterol and TG levels in the chylomicrons (CM) size range, suggesting that the postprandial production of CM particles was suppressed by ezetimibe.

CONCLUSIONS

These findings suggest that ezetimibe improves fasting lipoprotein profiles and postprandial hyperlipidaemia by suppressing intestinal CM production in patients with type IIb hyperlipidaemia and such treatment may prove to be effective in reducing atherosclerosis.

[Lipofibroadenoma of the thymus]

Here we report a case of a rare thymic tumors histologically diagnosed as lipofibroadenoma. The patient was a 32-year-old male who displayed an anterior mediastinal tumor on a chest computed tomography (CT) scan while being treated for pneumonia. The tumor was localized within the thymus, and the diameter was 3 cm. No significant change was observed in the tumor on a CT scan taken 6 months after the 1st scan. Suspecting a thymoma from the CT and magnetic resonance imaging (MRI) findings, we performed a thymothymectomy via a median sternotomy. The histopathological diagnosis was a lipofibroadenoma of the thymus. The findings resembled fibroadenoma of the breast. Lymphocytes were scarce within the tumor with abundant interstitial stroma, and the tumor epithelial cells displayed restiform and dendritic structures. The epithelial cells were mostly negative for Ki-67 immunohistochemical staining. A very small amount of calcification was detected within the tumor using alizarin red staining. Based on the histopathological findings, it was considered to be a benign tumor with little growth potential, and which had been present for a long period of time.

[Bloody sputum caused by hemorrhage around staple-lines 5 years after surgery; report of a case]

23 year-old non-smoking male who had underwent bilateral video-assisted thoracoscopic surgery (VATS) bullectomy for spontaneous pneumothorax using surgical stapler (Endo GIA, Tyco Healthcare) 5 years before, referred to our hospital due to hemoptysis. Chest computed tomography (CT) revealed infiltrative shadow surrounding stapled-line at right pulmonary apex. Aspiration-shadows were scattered in right lung parenchyma. Bronchoscopy revealed bloody clot extended from right B1 to main bronchi. These findings suggested that the cause of bloody sputum was bleeding from the tissue around staples used in VATS bullectomy. On admission he treated with hemostatic agents, and bloody sputum and abnormal CT shadows disappeared. Metallic surgical staplers may cause airway bleeding after surgery in its chronic stage, although complications due to them are rare.

Phase transformation of plasma-sprayed hydroxyapatite coating with preferred crystalline orientation

Highly oriented hydroxyapatite coatings (HACs) were obtained on titanium substrates through a radio-frequency thermal plasma spraying (TPS) method. XRD patterns showed that the HACs had crystallites with [001] preferred orientation vertical to the coating's surface. XRD results also indicated that tetracalcium phosphate crystallites in the as-sprayed HAC were oriented in the (100) direction. XRD peaks corresponding to tetracalcium phosphate, tricalcium phosphate and calcium oxide were absent after heat and hydrothermal treatment. The orientation degree of the HAC was influenced little by such post-heat treatments. Considering the crystallographic relationship between the tetracalcium phosphate in the as-sprayed HAC and the HA crystallites formed in the heat-treated HAC, these XRD results indicate that the tetracalcium phosphate in the as-prepared coatings transformed topotaxially into HA during the post-heat treatment. TEM and SEM analyses of the highly oriented HAC were conducted. The characteristic lamellar structure of TPS deposits was observed in cross-sections of the HAC. A prismatic texture was also observed in magnified SEM images. TEM observation showed that 200-800-nm-wide prismatic crystallites were formed in HA splats, and their longitudinal axis was oriented vertically to the coating's surface. SAD patterns showed that the longitudinal axis of the prismatic crystallites corresponded to the [001] zone axis of the HA crystal.