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Biomedical subjects

A Arad

Publications and source records attributed to A Arad.

9 recordsLinked to original sources
PubMed1999

Efficacy of topical application of eosin compared with zinc oxide paste and corticosteroid cream for diaper dermatitis.

BACKGROUND: Corticosteroids, zinc paste and eosin 2% are well-known topical agents for the treatment of moderate to severe diaper dermatitis. Among these treatments, the aqueous solution of eosin 2% is extensively used in several European countries, but not in the USA or Israel. OBJECTIVE: To assess the therapeutic efficacy of eosin 2% solution compared to the other treatment modalities for diaper dermatitis. METHODS: Fifty-four infants with diaper dermatitis, recruited from hospital wards and community clinics, were randomly assigned to three treatment groups: zinc oxide paste (containing allantoin 0.5%, cod liver oil 17% and zinc oxide 47epercnt;); clobetasone butyrate 0.05%, and aqueous solution of eosin 2%. The severity of the disorder was graded on a 6-point scale by observation and quantitative measurement of the lesions. The groups were compared for rates and time to heal. Due to the red color of eosin, a double-blind controlled study was impossible. RESULTS: Following 5 days of treatment, the rate of complete healing in the group treated with eosin (61%) was significantly higher (p = 0.0479) than that in the zinc oxide paste and corticosteroid groups (22 and 33%, respectively). Furthermore, in cases of partial healing, the degree of improvement was higher in the eosin group than the other two (p = 0.0205). The fastest improvement was observed in the group treated with corticosteroid cream. CONCLUSION: Considering the potential hazards of topical corticosteroids and the greater overall efficacy of eosin 2% solution, we suggest that eosin is the preferred treatment for diaper dermatitis.

Administration, Cutaneous↗
PubMed1999

Butyrylcholinesterase formulated in liposomes.

Exogenous cholinesterases have the potential to take part in defence against organophosphate toxins, by acting as scavenger systems. Postulating that formulation in liposomes could enhance the toxin-scavenging potential of these enzymes, we have initiated studies of such formulations and are reporting here our first steps, exploring butyrylcholinesterase (BChE) in multilamellar liposomes composed of phosphatidylcholine. We started by developing an essential research tool: a multisample, sensitive and rapid enzyme-activity assay, based on the Ellman reaction, that could be performed directly on liposome-containing samples. Using an ELISA reader equipped to follow time-dependant absorbency changes, 10 min sufficed to assay 96 samples simultaneously. Next, several key properties of liposome-formulated BChE were explored and the major findings were: (i) the encapsulated enzyme was found to retain its activity. (ii) Enzyme activity was found to increase (at constant enzyme concentration) in the presence of the lipid, in a lipid-concentration-dependant manner. Through data analysis it was possible to attribute this effect to changes in k(cat). (iii) Good, reproducible, encapsulation efficiencies (for macromolecules) in the range of 30% were obtained at liposome concentrations of 100 mM lipid. (iv) Free BChE was completely susceptible to proteolysis under conditions mimicking enzymically-hostile biological environments, whereas > or = 60% of the liposome-formulated BChE was protected, found to be inaccessible to the proteolytic enzymes. (v) Short-term exposures of free and liposome-encapsulated BChE to the inhibitor paraoxon, generated significant losses in enzyme activity. Residual activities of both BChE formulations dropped considerably over the paraoxon concentration range of 0.02-0.11 microM, down to 3 and 11% for free and liposome-encapsulated enzyme respectively. These data are a clear indication that the encapsulated BChE was accessible to the inhibitor, indicating that such liposomal formulations have the potential to perform as the desired scavenger systems.

Butyrylcholinesterase↗
PubMed1994

Molecular and cellular studies of hyaluronic acid-modified liposomes as bioadhesive carriers for topical drug delivery in wound healing.

Liposomes, modified into bioadhesive systems by the covalent anchoring of hyaluronic acid (HA) to their surface, were investigated for their abilities to act as site-adherent and sustained-release carriers of drugs for the topical therapy of wounds and burns. Epidermal growth factor (EGF) served as the test drug for growth factors and monolayers of the A431 cell line served as models of the in vivo designated targets. The hyaluronic acid was radiolabeled to carry 3H, through a deacetylation-reacetylation procedure, yielding specific activities in the range of 1 x 10(6) dpm/mg. The HA was bound to the surface of the liposomes, using carbodiimide to crosslink its carboxyl residues to amine residues at the liposomal surface. The latter was provided through the inclusion of phosphatidylethanolamine in the liposome formulation. Varying the initial HA/lipid ratio over the range 1-500 mg HA/mmol lipid, it was found that the increase in bound HA was linear, providing up to 80 mg HA/mmol lipid. The HA-modified, but not the nonmodified, liposomes were found to bind with high affinity (delta G degree in the range of -7 to -9 Kcal/mol) to monolayers of the A431 cell line. The HA-modified liposomes were found to encapsulate EGF at high yields (% encapsulation, > 87) and to act as sustained-release depots, the rate constant for the release of the encapsulated EGF in the range of 1.4 x 10(-3) h-1. Taking all of these findings together, it is concluded that these liposomes are bioadhesive sustained-release carriers of drugs, as desired, meriting further cellular and in vivo studies.

Cell Line↗
PubMed1989

Effect of pH on mutagenesis by thiols in Salmonella typhimurium TA102.

The mutagenicity of thiol (SH)-containing compounds was tested in Salmonella typhimurium TA102 in the liquid preincubation method. Cysteinyl-glycine (CG), cysteine ethyl ester (CEE), L- and D-penicillamine (PA), cysteine (Cys) and glutathione (GSH) were mutagenic to strain TA102 without metabolic activation. On a molar basis, CG was the most potent mutagen. The mutagenicity of the remaining compounds decreased in the order specified above. The mutagenic response of each thiol-containing compound was a function of the pKa of the thiol group and the pH of the preincubation mixture. This indicates that a thiolate anion, rather than a free thiol, is required for mutagenesis.

Chemical Phenomena↗
PubMedDate not supplied

Follicular carcinoma of the thyroid.

BACKGROUND: Follicular carcinomas of the thyroid are less common than papillary carcinomas of the thyroid, and the available data on prognostic factors are relatively scant. A retrospective study covering four decades was undertaken to evaluate clinical and pathologic findings with regard to their effect on prognosis. METHODS: In 195 cases of follicular carcinoma treated from 1954 to 1991 age, sex, histologic type (minimally invasive vs. widely invasive), tumor size, and local, regional, and distant spread as well as the contribution of treatment to survival were evaluated in relation to prognosis. RESULTS: Age was a significant prognostic factor: there was 100% survival of patients younger than 20 years of age at diagnosis and only one death in the 20-39 year age group. Sex was not a significant prognostic factor, although there was a tendency to a better prognosis in females. Tumor size was significant, more than 6 cm having a poor prognosis. Blood vessel invasion influenced prognosis for the first 10 years. The presence of distant metastases was significant regarding survival. Lymph node involvement had a negative effect on the outcome. CONCLUSIONS: The factors of age, tumor size, invasion of blood vessels, and distant metastases are significant predictors of survival for patients with follicular carcinoma, whereas sex is not; regional spread needs to be evaluated further.

Adenocarcinoma, Follicular↗