Effects of artepillin C on model membranes displaying liquid immiscibility

It has been hypothesized that the therapeutic effects of artepillin C, a natural compound derived from Brazilian green propolis, are likely related to its partition in the lipid bilayer component of biological membranes. To test this hypothesis, we investigated the effects of the major compound of green propolis, artepillin C, on model membranes (small and giant unilamelar vesicles) composed of ternary lipid mixtures containing cholesterol, which display liquid-ordered (lo) and liquid-disordered (ld) phase coexistence. Specifically, we explored potential changes in relevant membrane parameters upon addition of artepillin C presenting both neutral and deprotonated states by means of small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and confocal and multiphoton excitation fluorescence microscopy. Thermotropic analysis obtained from DSC experiments indicated a loss in the lipid cooperativity of lo phase at equilibrium conditions, while at similar conditions spontaneous formation of unilamellar vesicles from SAXS experiments showed that deprotonated artepillin C preferentially located at the surface of the membrane. Time-resolved experiments using fluorescence microscopy showed that at doses above 100 µM, artepillin C in its neutral state interacted with both liquid-ordered and liquid-disordered phases, inducing curvature stress and promoting dehydration at the membrane interface.

Patch Test in Children: Common Allergens and Comparison with Adult Group / 대한피부과학회지

BACKGROUND: Allergic contact dermatitis (ACD) was once regarded as a disorder of the adult population, while ACD in children was considered rare. However, ACD in children may be more common than previously realized and more recently, it has been estimated that more than 20% of the pediatric population is affected by ACD. However, in Korea results of patch testing in the pediatric population has not yet been reported. OBJECTIVE: The purpose of this study was to analyze allergens responsible for ACD in Korean children and investigate the influence of sex, involved site, and atopic dermatitis on contact allergen sensitization. We also wanted to compare the results between the pediatric and the adult group. METHODS: A retrospective analysis of all patch test results from our data base between 2009 and 2011 was performed. A total of 234 patients were patch tested. The pediatric population was defined as patients 18 years and younger, and total 30 pediatric patients were included. RESULTS: A total of 30 patch tested cases (male 12, female 18) were analyzed. Overall, 66.7% of pediatric patients had at least one positive reaction and common allergens were nickel sulfate (33.3%), thimerosal (13.0%), and black rubber mix (10.0%) in order of frequency. There were no significant differences between contact allergen sensitivity and sex or involved sites. However, in the atopic group, the positive reactions to wool alcohols were significantly higher than in the non-atopic group (p=0.0076). In adults, common allergens were nickel sulfate (34.8%), p-tert butylphenol formaldehyde resin (11.8%), cobalt chloride (11.3%) and thimerosal (11.3%) in order of frequency. This was not significantly different to the pediatric group. CONCLUSION: ACD in children is not uncommon and patch testing in suspected children revealed 66.7% of positive reaction.

Occupational Reproductive Function Abnormalities and Bladder Cancer in Korea

The purpose of this study was to review occupational reproductive abnormalities and occupational bladder cancer in Korea and to discuss their toxicological implications. Reproductive dysfunction as a result of 2-bromopropane poisoning was first reported in Korean workers. In 1995, 23 of the 33 workers (25 female and 8 male workers) who were exposed to 2-bromopropane during the assembly of tactile switch parts developed reproductive and/or hematopoietic disorders. A total of 17 (68%) workers were diagnosed with ovarian failure. Two of the eight male workers experienced azoospermia and four workers experienced some degree of oligospermia or reduced sperm motility. In summary, 2-bromopropane poisoning caused severe reproductive effects in Korean workers. The prognosis was poor for reproductive dysfunction. A few cases of occupational bladder cancer have been reported in Korea, whereas other cancers of the urinary tract have not been reported after occupational exposure. A few cases of benzidine-induced cancer have been reported in Korea and 592 workers in Japan have received compensation for benzidine and beta-naphthylamine-induced cancer. In conclusion, a few cases of benzidine-induced occupational bladder cancer have been reported in Korea. However, benzidine-induced bladder cancer will likely be an important occupational health issue in Korea in the coming years.

Synthesis, characterization and electrial properties of poly N-Phenyl 2-Naphthyl amine and poly N-Ethyl aniline

Poly n-phenyl-2-naphthyl amine [PNPNA] and poly N-ethyl aniline [PNEA] have been prepared using potassium persulphate as an oxidizing agent. The polymers were characterized by various methods using spectrophotometric measurements, e.g., I.R. and UV-visible. Thermal gravimetric analysis [TGA] for PNEA indicated its great thermal stability up to 430 degree. A.C. resistivity and capacitance measurements have been used to characterize the electrical properties of the prepared polymers in the temperature ranges from 25 degree to 160 degree for and from 25 degree to 240 degree for PNEA. Log p, capacitance, Ea and dielectric constant values were obtained at different frequency ranges from 5OHz up to 100 kHz. The results suggest hopping conduction mechanism for the PNPNA pellets, the increase in conductivity being governed by the interchain hopping of polarons acting as charge carriers. The PNEA pellets, on the other hand, showed higher resistivity values at all frequency ranges than those of PNPNA. Also the A.C. resistivity tends to become temperature independent. Accordingly, the conductivity increased with increasing frequency. This behaviour is attributed to the presence of ethyl groups in the polymer chain that introduce new trap levels within the localized states

Basic aminopeptidase from rabbit kidney: purification and partial characterization

The aminopeptidase activity of a homogenate of rabbit kidney treated with Triton X-100 was measured using L-aminoacyl-2-naphthylatmides (AA-NA). After gradient elution ion-exchange chromatography, four peaks of aminopeptidase activity were eluted. The enzyme eluted at 450 muS containing 33.5 per cent of the activity towards Arg-NA was applied to a Superdex 75 column and presented only one protein band on 10 per cent SDS-polyacrylamide gel electrophoresis. This enzyme has an apparent molecular mass of 78 kDa, is five-fold activated by 0.15 M NaCl and the highest Vmax/Km ratio was obtained with Arg-NA. Enzyme activity was inhibited 100 per cent by 0.13 mM sodium p-hydroxymercuribenzoate, 20 per cent by 0.75 mM EDTA and 100 per cent by 0.66 mM ophenanthroline. Puromycin and bestatin behaved like competitive inhibitors with a Ki of 0.60 mM and 5.0 muM, respectively.

Synthesis of some aminonaphthalene and 5-substituted uracil nucleosides derivatives

Some amino naphthalene nucleosides were prepared by the reaction of both of 1-amino, 1-aminomethyl, 1,5-diamino and 2,6-bis [aminomethyl] naphthalene derivatives with 2,3,5-tri-O-acetyl ribofuranosyl chloride. On the other hand, the reactions of 2',3'-O-isopropylidene 5-amino uridine and its 5-aminomethyl analogue with gluconolactone and the reactions of 2',3'-O-isopropylidene-5-chloromethyl uridine with sodium N-methyl taurinate have been described

Formation of 8-hydroxydeoxyguanine moiety in human bladder cellular DNA by bladder carcinogens / 대한비뇨기과학회지

The 8-hydroxydeoxyguanosine (8-OH-dG), DNA adduct produced by oxygen radical-induced hydroxylation of C-8 position of guanine residue is accepted as to cause mutation and associate with carcinogenesis, and there are many carcinogens those produce oxygen radicals. Although many carcinogens have been accepted to induce bladder tumor, there is little known about the mechanism of carcinogenesis by these carcinogens. Following administration of bladder carcinogen, N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN), 4-Aminobiphenyl (4-ABP), 2-naphthylamine (2-NA) and N-methyl-N-nitrosourea (MNU) to human normal bladder epithelial cell, the results were obtained.1. Following administration of aromatic amine carcinogen, BBN, 4-ABP and 2-NA, the content of 8-OH-dG was increased to about 30-35 % although some variation of time existed according to the kinds of carcinogens. 2. Following administration of MNU, the content of 8-OH-dG was increased to about less than 3 % over all times. 3. Following administration of H2O2 that produce oxygen radicals without metabolism, the content of 8-OH-dG was increased to about 37 %. From this result, it can be supposed that the in crease of 8-OH-dG by carcinogens is induced by oxygen radical.The results obtained suggest that there are some enzymes in bladder epithelium that are related to metabolism of aromatic amine carcinogens and modification of DNA in bladder epithelial cell by the oxygen radicals, that is Formation of 8-OH-dG, is induced in carcinogenesis of bladder tumor byaromatic amine carcinogens.