Nifedifine was incorporated in ethyl cellulose microspheres using the solvent evaporation process. The effects of the EC concentrations, the methylene chloride volumes and the stirring rates on the drug release from microspheres were studied. The dissolution profile of a microsphere formulation was found to be similar to that of adalat retard by the optimization method and the statistical analysis. This formulation may be useful in a nifedipine sustained release dosage form
Nifedipine ; Microspheres

Radioembolization using beta-emitting yttrium-90 microspheres is being increasingly used for the treatment of primary and metastatic liver cancers. It is a form of intra-arterial brachytherapy which delivers intense radiation to liver tumors with little embolic effect; this mode of action results in unique post-treatment imaging findings. It is important to understand these imaging findings to avoid misinterpretation of tumor response and to determine further management of the disease. Herein, we discuss the current concepts for assessing tumor response, common post-treatment imaging features, and associated complications following radioembolization.
Brachytherapy ; Liver Neoplasms ; Liver* ; Microspheres

PURPOSE: The adverse reactions of prostaglandin E1(PGE1) are troublesome in the preoperative management of critical patients with ductus dependent congenital heart disease, and a preparation with less adverse reactions is preferable. The effects of Lipo PGE1, a new preparation of PGE1 contained in lipid microspheres, were compared with those of conventional PGE1(PGE1-CD). METHODS: Lipo PGE1 was infused at a rate of 5 ng/kg/min in 19 patients, PGE1-CD at a rate between 10 and 50 ng/kg/min in 15 patients. The effects of drugs were assessed in terms of clinical response rate and overall safety. RESULTS: Clinically, both treatment were effective in relieving cyanosis and hypoxemia except in patients already having either a closed ductus or severe hypoxemia and acidosis. The increments of PaO2 1 hour after infusion were 10.9 and 6.2 mmHg (p>0.1), respectively and those 4 hours postinfusion were 16.0 and 7.8 mmHg(p<0.05), respectively. Even though there was no significant difference in clinical response rate(78.9 vs 60.0%, p>0.1), the mean dose of Lipo PGE1 at appearance of response was about 1/5 of that of PGE1-CD in overall patients and also in patients with ductus dependent pulmonary circulation(6.7 vs 31.7 ng/kg/min, p<0.005). The adverse reactions occurred in 52.6% of the patients given Lipo PGE1, while it was 86.7% in those administered PGE1-CD(p<0.05). The adverse reactions in Lipo PGE1 group was much less severe than that in PGE1-CD group. There was a significant difference in overall safety between the two drugs(84.2 vs 40%, p<0.01). As the incidence of the adverse reactions increased at dose over 5 ng/kg/min, the initial dose of 5 ng/kg/min seemed to be appropriate for Lipo PGE1. CONCLUSIONS: Lipo PGE1 was effective at a lower dose than was PGE1-CD, and was associated with fewer or less severe adverse reactions, and is therefore judged to be more suitable for clinical use than conventional PGE1-CD.
Acidosis ; Alprostadil ; Anoxia ; Cyanosis ; Heart Defects, Congenital* ; Humans ; Incidence ; Microspheres

BACKGROUND: Among the various physiochemical stimuli, hypoxia has been known to cause coronary vasodilation. In contrast to this, endothelial dependent contracting factor(EDCF) was shown to be secreted by hypoxia and overall physiological roles of these apparently contradicting two phenomena are not clear. Although coronary vasodilation is dominant in epicardial coronary artery by hypoxia, collateral circulation may show different response from epicardial coronary artery to the same stimulus and effect of hypoxia on the vasomotor tone of collateral vessels has not been established. METHODS: Left circumflex coronary artery was chronically occluded using Ameriod occluder in the canine model and myocardial blood flow through collateral circulation was measured using microsphere during induced regional hypoxia. RESULTS: 1) Myocardial blood flow measurements during oxygenated and hypoxic solution infusion were 1.11+/-0.11 mg/min/g and 1.12+/-0.10 ml/min/g respectively in normal perfused zone(LAD territory), but in the collateral dependent zone(LCX territory) blood flow decreased significantly during hypoxic solution infusion(0.55+/-0.17 ml/min/g vs 0.43+/-0.21 ml/min/g)(p<0.05). Also myocardial blood flow ratio(LCX/LAD territory) decreased significantly during hypoxic solution infusion(0.49+/-0.16 vs 0.39+/-0.02)(p<0.05). 2) In collateral dependent zone, endocardial and epicardial blood flow ratio showed significant redistribution during hypoxic solution infusion. 3) After verapamil administration, myocardial blood flow in collateral dependent zone increased from 0.43+/-0.21ml/mg/g to 0.56+/-0.23 ml/mg/g(p<0.05). Also myocardial blood flow ratio(LCX/LAD territory) increased from 0.39+/-0.20 to 0.50+/-0.20 to 0.50+/-0.21 after verapamil administration. CONCLUSION: Hypoxia seems to cause vasoconstriction in collateral vessels and redistribution of blood flow in collateral dependent zone and these effects can be reversed by verapamil.
Anoxia* ; Collateral Circulation* ; Coronary Vessels ; Microspheres ; Oxygen ; Vasoconstriction ; Vasodilation ; Verapamil

Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma.
Carcinoma, Hepatocellular* ; Glass* ; Humans ; Liver ; Liver Neoplasms ; Microspheres* ; Neoplasm Metastasis

Polymethyl-methacrylate(PMMA; Artecoll(R)) microspheres suspended 1 : 3 in a 3.5% collagen solution has been used as an injectable implant for long lasting correction of wrinkles and minor skin defects. The patients with mandibular prognathism have increased necessity for nasal augmentation.Usually these patients usually get an additional rhinoplasty after orthognathic surgery. The purpose of this study is to evaluate the result of PMMA injection for nasal ridge augmentation simultaneously with the orthognathic surgery. PMMAs were injected to the nasal dorsum of 13 patients with mandibular prognathism to augment the nasal ridge at the end of the orthognathic surgery. The cephalometric X-ray and clinical facial photograph were taken at 2, 4 and 6 months after operation. Using S-N line, we calculated the change of soft tisuue on the nasal ridge and also investigated the degree of patients satisfaction at 6 months after operation. Most of the patients were satisfied with their nasal ridge height status from moderate to good degree. The average amount of nasal ridge augmentation was 1.4 +/- 0.5 mm immediately after operation, 1.2 +/- 0.4 mm at 2 months after operation. The postoperative nasal ridge height seemed to be remained stable after 2 months. Intraoperative PMMA injection is considered to be simple and effective technique which can be used for the minor augmentation of nasal ridge in the orthognathic patients.
Collagen ; Humans ; Microspheres* ; Orthognathic Surgery* ; Polymethyl Methacrylate* ; Prognathism ; Rhinoplasty ; Skin

As a new type of functional material, magnetic thermosensitive polymeric microspheres offer high potential application in various fields, particularly in bioengineering and biomedical fields. In this review, the development of synthesis and application of magnetic thermosensitive polymeric microspheres was summarized, and the research trends were also discussed.
Biocompatible Materials ; chemistry ; Magnetics ; Microspheres ; Particle Size ; Polymers ; chemistry ; Temperature

OBJECTIVEThe aim of this study was to prepare Pingyangmycin Albumin Microspheres (PYM-AMS) for arteriovenous malformations treatment.

METHODSPYM-AMS was prepared at 140 degrees C by the method of emulsification-heat solidification and its characteristics were evaluated, such as morphosis, particle size, drug loading (DL%), encapsulation efficiency (EE%), stability and drug sustained-releasing in vitro. After being packaged, PYM-AMS were sterilized with 13.7 kGy of 60Co. Small samples of PYM-AMS were packaged in small bottles and stored at 3 - 5 degrees C, 15 - 25 degrees C, 37 degrees C for 3 months, then checked the change of morphology, DL, EE and the release rate.

RESULTSThe surface of particles was smooth and integrated. The average diameter of PYM-AMS particles was 139.422 microm and 80% was in the range of 56 - 251 microm. The mean DL% and EE% were 26.47% and 84.3%, respectively. PYM released fast in 5 h, but then released slowly. 88.65% drugs were released in 24 h, and t50 was 1.5 h. There was no obvious change of the morphology, DL,EE and the release rate of PYM-AMS stored at 3 - 5 degrees C 15 - 25 degrees C, 37 degrees C for 3 months.

CONCLUSIONPYM-AMS prepared in this study had sustained-release effect, high drug loading and high stability. Albumin is a good carrier of PYM embolization agent.

Scintillation proximity assay (SPA) is a unique type of radioimmunoassay and makes it possible to use radioisotopes for monitoring binding reactions continuously without separation procedure. Microbeads containing a fluorophor are covalently linked to antibody or receptor. When a radiolabeled antigen or ligand is added it binds to the beads and the emitted short range electrons, excite the fluorophor in the beads. The light emitted can be measured in a scintillation counter. 3H or 125I has been used for SPA. The sensitivities achieved with SPA are comparable to the sensitivities of other procedures. SPA is applicable to immunology, receptor binding, monitoring interactions of biomolecules and study for the kinetics of interaction between receptors and ligands.
Allergy and Immunology ; Kinetics ; Ligands ; Microspheres ; Radioimmunoassay ; Radioisotopes ; Scintillation Counting

During the most recent decade, remarkable progress has taken place in intra-arterial therapy for hepatocellular carcinoma. Advances in knowledge of hepatic vascular anatomy and tumor blood supply have contributed to the safety and efficacy of intra-arterial therapies. Technological advances in C-arm computed tomography and microcatheter systems have improved the technical success rates for superselective or ultraselective catheterization of tumor-feeding arteries. Drug-eluting bead technology has provided the option of performing chemoembolization with less systemic exposure to anticancer drugs and a more standardized delivery. Radio-embolization with yttrium-90 microspheres has emerged as a promising option offering increased quality of life. In addition, chemoembolization plays a central role in recently developed combination therapy strategies. In this era of advanced technologies and new treatment options, efforts should be made to understand the advantages and disadvantages of new technologies and treatment strategies and to apply them properly, which may lead to better local control of tumors, better quality of life, and longer patient survival.
Arteries ; Blood ; Carcinoma, Hepatocellular* ; Catheterization ; Catheters ; Humans ; Microspheres ; Quality of Life