Carbon materials as new nanovehicles in hot-melt drug deposition

The application of commercially available carbon materials (nanotubes and porous carbons) for the preparation of drug delivery systems is studied. We used two types of carbon nanotubes (CNT) and two activated carbons as potential materials in so-called hot-melt drug deposition (HMDD). The materials were first studied using Raman spectroscopy. Paracetamol was chosen as a model drug. The performed thermal analysis, kinetics, and adsorption-desorption studies revealed that nanoaggregates are formed between carbon nanotubes. In contrast, in pores of activated carbon we do not observe this process and the drug adsorption phenomenon mechanism is simply the filling of small pores. The formation of nanoaggregates was confirmed by the results of GCMC (grand canonical Monte Carlo) simulations and the study of the surface area on nitrogen adsorption-desorption isotherms. The application of carbon nanotubes in HMDD offers the possibility of controlling the rate of drug delivery. Performed MTT tests of nanotubes and drug-loaded nanotubes show that the observed decrease in cell viability number is caused by the influence of the cytostatic properties of nanotubes-they inhibit the proliferation of cells. The carbon nanotubes studied in this paper are essentially nontoxic.

Secondary intention healing in skin surgery: our own experience and expanded indications in hidradenitis suppurativa, rhinophyma and non-melanoma skin cancers

BACKGROUND

There are many situations in integument surgery in which secondary intention healing (SIH) may bring results comparable or even superior to those obtained with primary intention healing.

OBJECTIVE

To present our own methods of employing SIH in surgical treatment of different skin lesions. Moreover, to delineate the extended indications for SIH as a first-line method of wound treatment.

METHODS

Between 1999 and 2009, we conducted 236 operations followed by SIH in the group of 195 patients. Two independent investigators and the patients carried out post-operative assessment (at 12 months) of both cosmetic and functional results of operations (data for 142 patients). Moreover, at 3 and 12 months, patients were asked for self-evaluation of the outcomes of surgical procedures using the visual analogue scale (VAS).

RESULTS

The most frequent indications for SIH were defects after the excision of non-melanoma skin cancers and hidradenitis suppurativa lesions. Depending on localization, the mean extent of the post-operative wounds prepared for SIH ranged from 0.8to 85.7 cm(2). The healing lasted 2-12 weeks. The most important factor was the size of the wound (r = 0.59; P < 0.001). The assessment at 12 months revealed that cosmetic/functional outcomes were evaluated as 'good' or 'excellent' in 89/83% and 72/70% cases, according to patients and physicians respectively. VAS showed that evaluation scores at 3 months post-surgery were significantly lower than at 12 months (P < 0.0001).

CONCLUSION

SIH is a safe and efficient form of treatment for various post-operative skin defects. In certain areas of the body, SIH shows favourable cosmetic and functional effects. In these cases, it may even be regarded as the method of choice.

Role of base-excision repair in the treatment of childhood acute lymphoblastic leukaemia with 6-mercaptopurine and high doses of methotrexate

Methotrexate (MTX) and 6-mercaptopurine (6MP) are the most commonly used drugs in the therapy of childhood acute lymphoblastic leukaemia (ALL). The main genotoxic effect of MTX resulting from inhibition of thymidylate synthase is mis-incorporation of uracil into DNA, which is considered essential for the effectiveness of the Protocol M in ALL IC BFM 2002/EURO LB 2002 regimens. In this study, we investigated the level of basal and induced DNA damage as well as the effectiveness of DNA repair in lymphocytes of children with ALL at four time-points during therapy with MTX and 6MP. To assess DNA damage and the efficacy of DNA repair we used the modified alkaline comet assay with uracil DNA glycosylase (Udg) and endonuclease III (EndoIII). In addition, we examined the induction of apoptosis in the lymphocytes of the patients during treatment. Finally, we compared the activity of base-excision repair (BER), involved in removal of both uracil and oxidized bases from DNA in lymphocytes of children with ALL and lymphocytes of healthy children. BER efficiency was estimated in an in vitro assay with cellular extracts and plasmid substrates of heteroduplex DNA with an AP-site. Our results indicate that there is a significant decrease in the efficacy of DNA repair associated with an increased level of uracil in DNA and induction of apoptosis during therapy. Moreover, it was found that the BER capacity was decreased in the lymphocytes of ALL patients in contrast to that in lymphocytes of healthy children. Thus, we suggest that an impairment of the BER pathway may play a role in the pathogenesis and therapy of childhood ALL.

XPD Common Variants and their Association with Melanoma and Breast Cancer Risk

There are suggestions in the literature that common variants in the XPD gene may be associated with an altered risk of melanoma and breast cancer. To establish if the XPD common variants Asp312Asn and Lys751Gln are associated with an increased melanoma or breast cancer risk we performed an association study based on genotyping 426 unselected patients with malignant melanoma (MM) and 1830 consecutive breast cancer cases and compared the results to 1262 geographically matched newborns, 621 adults from the region of Szczecin (unselected for age and cancer family history), 421 healthy adults age- and sex-matched with the melanoma cases and 511 healthy controls matched with the breast cancer patients from the region of Szczecin. Additionally we examined the prevalence of three additional XPD variants, Gly156Gly, Leu485Pro and Arg112His amongst the 421 unselected melanoma patients. All of the variants when evaluated singularly were found not to be associated either with melanoma or breast cancer risk in younger or older patients. A modest association was observed with breast cancer risk when the Lys751Gln_CC/Asp312Asn_AA genotype (OR=1.5, p<0.05) segregated together. Individuals harboring the Lys751Gln_CC/Gly156Gly_CC genotype were significantly over-represented among late-onset melanoma cases (OR=1.7, p<0.05). The results of analyses of linkage disequilibrium and haplotype frequency support the thesis that a combination of at least two SNPs (Lys751Gln_CC/Gly156Gly_CC or Lys751Gln_CC/Asp312Asn_AA) inherited as a haplotype was associated with disease. These two pairs of SNPs could therefore be regarded as a single hereditary unit that would have a very small probability of being disrupted by recombination. Additional studies are required to determine whether these particular changes can be associated with an increased risk of other malignancies at different sites of origin.

Brooke-Spiegler syndrome

The Brooke-Spiegler syndrome is an autosomal dominant one characterized by cylindromas, trichoepitheliomas and occasionally spiradenomas. Within a given family, some members may have cylindromas whereas others may have trichoepitheliomas or both. We describe the coexistence of trichoepithelioma papulosum multiplex (also known as epithelioma adenoides cysticum of Brooke) and cylindromas in a 30-year-old man, and discuss the relationship between these two autosomal dominant syndromes.