The interaction of calcium and local anesthetics was investigated with the lipid extracted human RBC membrane fragments treated with carbodiimide in order to titrate carboxyl groups. A water soluble carbodiimide [1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide methotoluene-p-sulfonate], referred to as a carbodiimide reagent, and glycine methylester were used for this purpose. About 76% of carboxyl groups of the fragments were modified at a concentration of 0.05M carbodiimide reagent. The interaction of calcium and local anesthetics such as procaine and lidocaine with these fragments still showed typical competition. However, when the calcium binding was decreased to 8% at a higher concentration of carbodiimide reagent (0.08M), the local anesthetics still inhibited the calcium binding, but were not competitive in nature. In other words, if concentrations of the carbodiimide reagent were raised, the degree of inhibition by the local anesthetics was gradually decreased and was not competitive in nature. Finally, no inhibition was demonstrated when the concentration of the reagent was 0.1 to 0.4M. The above findings, seem to suggest that local anesthetics such as procaine and lidocaine interact with carboxyl groups, in addition to phosphodiester groups of phospholipids as previously reported, and inhibited competitively calcium binding to carboxyl groups of the membrane fragments.
Anesthetics, Local/pharmacology* ; Calcium/metabolism* ; Carbodiimides/pharmacology* ; Cell Membrane/metabolism ; Erythrocytes/metabolism* ; Human ; In Vitro ; Protein Binding

The interaction of calcium and local anesthetics was investigated with the lipid extracted human RBC membrane fragments treated with carbodiimide in order to titrate carboxyl groups. A water soluble carbodiimide [1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide methotoluene-p-sulfonate], referred to as a carbodiimide reagent, and glycine methylester were used for this purpose. About 76% of carboxyl groups of the fragments were modified at a concentration of 0.05M carbodiimide reagent. The interaction of calcium and local anesthetics such as procaine and lidocaine with these fragments still showed typical competition. However, when the calcium binding was decreased to 8% at a higher concentration of carbodiimide reagent (0.08M), the local anesthetics still inhibited the calcium binding, but were not competitive in nature. In other words, if concentrations of the carbodiimide reagent were raised, the degree of inhibition by the local anesthetics was gradually decreased and was not competitive in nature. Finally, no inhibition was demonstrated when the concentration of the reagent was 0.1 to 0.4M. The above findings, seem to suggest that local anesthetics such as procaine and lidocaine interact with carboxyl groups, in addition to phosphodiester groups of phospholipids as previously reported, and inhibited competitively calcium binding to carboxyl groups of the membrane fragments.
Anesthetics, Local/pharmacology* ; Calcium/metabolism* ; Carbodiimides/pharmacology* ; Cell Membrane/metabolism ; Erythrocytes/metabolism* ; Human ; In Vitro ; Protein Binding

Adult ; Carbodiimides ; poisoning ; Humans ; Male ; Methylamines ; poisoning ; Occupational Exposure ; Young Adult

Lipase (EC3.1.1.3) from Candida sp. 99-125 was immobilized on chitosan by chemical covalence. Lipase was first immobilized to chitosan beads by activating its hydroxyl groups with carbodiimide followed by cross-linking more lipase to the amino groups with glutaraldehyde. In this article, different factors that influenced the immobilization were investigated, and the optimum conditions were ascertained. Comparative studies of organic solvent and thermal stability between free lipase and immobilized lipase were conducted. Immobilization enhanced the lipase stability against changes of temperature and organic solvent. Immobilization lipase can be reused in the synthesis system of palmitate hexadecyl. Operational stability tests indicated that the immobilized lipase occurs after 16 consecutive batches, the conversion rate remained 85%. Such results revealed good potential for recycling under esterification system.
Candida ; enzymology ; Carbodiimides ; chemistry ; Chitosan ; chemistry ; Cross-Linking Reagents ; Enzyme Stability ; Enzymes, Immobilized ; Lipase ; metabolism ; Palmitates ; chemistry

UNLABELLEDOBJECTIVE Crosslink decellularized canine carotid artery allograft by EDC [1-3-(dimethylamino)propyl-3-ethylcarbodiimide methiodide] and evaluate the biocompatibility of it.

METHODSUse the multi-step detergent-enzyme method to construct decellularized canine carotid artery allograft and cross-link it by EDC with the weight ratio of decellularized artery to EDC 1:1 and 1:2. Evaluate the biocompatibility of it by the cytotoxical MTT test and the rat subdermal bury test.

RESULTSDecellularized canine carotid artery cross-linked by EDC has a lower degradation rate treated by collagenase type II, the result of MTT test show that the EDC cross-linked decellularized artery has no cytotoxity and the rat subdermal bury test show that crosslinking greatly enhance the ability of decellularize artery to resist the enzyme degradation and lower the immune reaction. The more the artery was cross-linked , the more effects it has.

CONCLUSIONSDecellularized canine carotid artery cross-linked by EDC has fairly good biocompatibility and ability to resist the collagenase degradation.

Animals ; Biocompatible Materials ; Carbodiimides ; Carotid Artery, Common ; transplantation ; Cross-Linking Reagents ; Dogs ; Female ; Male ; Materials Testing ; Rats ; Rats, Sprague-Dawley ; Tissue Engineering

OBJECTIVE: Authors aimed to determine the targeting ability of vascular endothelial growth factor receptor 2 (VEGFR2)-conjugated quantum dots (QDs) in vitro, and apply it for a xenograft prostate cancer mouse model. MATERIALS AND METHODS: Conjugation reaction of QDs was performed by using the N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and sulfo-(N-hydroxysulfosuccinimide) (Sulfo-NHS). The human umbilical vein cord endothelial cells (HUVECs) were incubated with QDs, conjugated with antiVGFR2, to see a specific binding in vitro. Fluorescent cell images were taken by a confocal microscope. The human prostate cancer cells (PC3) were injected to five nude mice on hind limbs to make the xenograft tumor model. QD-antiVEGFR2 antibody complex was injected into the tumor model and fluorescence measurements were performed at 1, 4, 9, 12, 15, and 24 hours after the injection. RESULTS: The specific interaction between HUVECs and QD-antiVEGFR2 antibody was clearly shown in vitro. The in vivo fluorescence image disclosed that there was an increased signal of tumor, 12 hours after the injection of QDs. CONCLUSION: By showing endothelial cells binding with QDs-antiVEGFR2 antibodyand an experimental application of the antibody for VEGFR2 imaging in the prostate cancer xenograft mouse model, we suggests that the antibody-conjugated QDs can be a potential imaging tool for angiogenesis of the cancer.
Animals ; Carbodiimides/pharmacology ; Cell Line, Tumor ; Disease Models, Animal ; Electrophoresis, Agar Gel ; Fluorescence ; Male ; Mice ; Mice, Nude ; Microscopy, Confocal ; Neovascularization, Pathologic/*pathology ; Prostatic Neoplasms/*pathology ; *Quantum Dots ; Succinimides/pharmacology ; Transplantation, Heterologous ; Vascular Endothelial Growth Factor Receptor-2/*antagonists & inhibitors

Air Pollutants, Occupational ; analysis ; Cyanamide ; analysis ; Spectrophotometry ; Workplace

OBJECTIVETo establish a method for determining cyanamide in workplace air by high-performance liquid chromatography (HPLC).

METHODSAir samples were collected from the workplace using the shock absorption tube containing water solution at a rate of 2.8∼3.0 ml/min for 60 min; dansyl chloride was used as a derivatization reagent to conduct pre-column derivatization, and the procedure was as follows: acetone solution (2.5 ml), mixed solution (1.0 ml) containing 0.016 mol/L Na2CO3 and 0.184 mol/L NaHCO3, and 10 mg/ml acetone solution of dansyl chloride (0.5 ml) were added into the samples, and reaction proceeded in a water bath (50 °C) for 1 h. HPLC was performed on an ODS C18 column (250 mm × 4.6 mm, 5 üm) with a mobile phase of acetonitrile-phosphate buffer (35:65) at a flow rate of 1.0 ml/min and a column temperature of 25°C; a fluorescence detector was used at an excitation wavelength of 360 nm and an emission wavelength of 495 nm.

RESULTSThe minimum detectable concentration of cyanamide was 0.05 üg/ml; a good linear relationship was noted when the concentration of cyanamide was 0.2∼100.0 üg/ml; the intraday relative standard deviation (RSD) was 0.28%∼1.18%, and the interday RSD was 0.22∼2.16%; the recovery rate was 95.7%∼103.0%, and the sampling efficiency was 95.8%∼96.9%. Water solution of cyanamide (pH<6.5) could be stable in the dark at room temperature for 7 d.

CONCLUSIONThis method is stable, reliable, easy to operate, and highly sensitive and suitable for determination of cyanamide in workplace air.

Air Pollutants ; analysis ; Chromatography, High Pressure Liquid ; methods ; Cyanamide ; analysis ; Occupational Exposure ; analysis ; Workplace

BACKGROUND AND OBJECTIVES: Congenital middle ear cholesteatoma (CMEC) is a keratinous mass behind an intact tympanic membrane. CMEC does not have a history of instrumentation and is less common than acquired one. Many theories have been put forward to explain the pathophysiology of CMEC, however, none of these so far have been convincingly proven. This clinical study was performed to investigate the characteristic features of CMEC and to evaluate the correlation between pathophysiology and CMEC by retrospectivly reviewing the cases. MATERIALS AND METHOD: The medical records of patients who underwent otologic procedures at the hospitals of the Catholic university from January 1993 to September 1998 have been reviewed. They were ten males and four females, ranging in age from 4 to 59 (mean age 18). RESULTS: Three of the 14 patients had the lesions isolated to the anterosuperior quadrant of the mesotympanum which were cystic, easily removed and did not affect hearing. The others had more serious condition with extension into the posterior mesotympanum, which were large, often too extensive to indicate a formative site, and causing ossicular damage. CONCLUSION: CMEC presents in two distinctive forms according to the site of formation: the anterosuperior and posterior mesotympanum. The review suggest that the pathophysiology of posterior lesions may be different from anterior ones. For early diagnosis of CMEC, screening program should be carried out in children to prevent the more extensive diseases.
Child ; Cholesteatoma, Middle Ear* ; CME-Carbodiimide ; Ear, Middle* ; Early Diagnosis ; Female ; Hearing ; Humans ; Male ; Mass Screening ; Medical Records ; Tympanic Membrane

BACKGROUND AND OBJECTIVES: Congenital middle ear cholesteatoma (CMEC) is a rare entity that may go undiagnosed for years. Aims of this study were to assess the characteristic features and recurrence of CMEC in pediatric patients of different stages and to determine the value of preoperative CT scan in CMEC. SUBJECTS AND METHOD: Thirty cases of CMEC under 15 years old that had been treated at the hospitals of the Catholic University from 1995 through 2005 were reviewed retrospectively. The age range was from 2 to 13 with the mean age of 6.2. The main outcome measures were CT findings, surgical findings, recurrence rate and hearing assessment. RESULTS: Preoperative CT scan accurately predicted the extent of the cholesteatoma seen during surgery in 25/30 (83.3%). The recurrence rate of CMEC was 6.7% (2/30) and all of recurrent cases were belonged to stage IV. In the recurrent cases, cholesteatomas were extended to sinus tympani and facial recess at revisional operation as well as at the initial operation. CONCLUSION: Preoperative CT scan is essential in defining the extent of existing pathology. The intra-operative CMEC extension and location influence the outcome of surgery. In the higher stages, careful eradication of disease, particularly in the region of sinus tympani and facial recess, are recommended.
Adolescent ; Child* ; Cholesteatoma ; Cholesteatoma, Middle Ear* ; CME-Carbodiimide ; Ear, Middle* ; Hearing ; Humans ; Outcome Assessment (Health Care) ; Pathology ; Recurrence ; Retrospective Studies ; Tomography, X-Ray Computed