Evaluation of buccal methyl-beta-cyclodextrin toxicity on human oral epithelial cell culture model

Cyclodextrins, especially methylated beta-cyclodextrins offer several advantages for drug delivery which include improved drug solubilization, protection against physicochemical and enzymatic degradation, as well as a potential for absorption improvement. However, little or no data are available for their use as drug penetration enhancer via the buccal route. This study focuses on the toxicity of randomly methylated beta-cyclodextrin (RAMEB) on buccal mucosa using a reconstituted human oral epithelium model composed of TR 146 cells. Toxicity of RAMEB on TR 146 cells was evaluated by measuring cell viability (MTT assay) and membrane damages followed by LDH release after single and repeated exposures to RAMEB solutions. Inflammatory effects of RAMEB are also considered by measuring expression of interleukin-1alpha and are supported by histological examination. The present results indicate that 10% RAMEB results in cytotoxic and inflammatory effects depending on time exposure, whereas 2% and 5% RAMEB do not induce tissue damages even after 5 days of repeated exposures. Therefore, the highly water-soluble RAMEB is thought to be a safe candidate as an excipient for buccal mucosal drug delivery.     

O-linked glycosylation and functional incompatibility of porcine von Willebrand factor for human platelet GPIb receptors

BACKGROUND: Xenograft rejection is associated with vascular inflammation, thrombocytopenia and the accelerated consumption of coagulation factors. Primary biological incompatibilities of the xenograft in the regulation of clotting appear to amplify pathological processes associated with rejection. The functional incompatibility of porcine von Willebrand factor (vWF) expressed within the xenograft vasculature may heighten interactions with the primate platelet receptor GPIb, hence augmenting formation of platelet microthrombi and vascular injury. Here, we address the functional impact of O-linked glycosylation of the vWF A1 domain on primate platelet activation. METHODS: Recombinant human or porcine vWF A1-domains were transiently over-expressed in COS-7 cells as FLAG-tagged fusion protein, linked to plasma membranes via GPI anchors. O-linked glycosylation was blocked by the addition of phenyl-alpha-GalNAc2 to cultures. Expressed vWF-A1 domains were characterized utilizing cytofluometric- and Western blot analyses. RESULTS: Cytofluometric analysis confirmed equivalent levels of human and porcine vWF A1-domain expression irrespective of the levels of O-linked glycosylation. Differential glycosylation patterns of vWF-A1 under these conditions were confirmed by Western blot analyses. Native porcine vWF A1-domains had enhanced human platelet activation potential when compared with human recombinant vWF A1. However, the loss of O-linked glycosylation abolished differences in aggregatory responses between human and porcine vWF A1 domains. CONCLUSIONS: Various degrees of O-linked glycosylation of vWF-A1-domains modulate levels of functional interaction with platelet receptor GPIb and consequent platelet aggregation responses in vitro. These data may have implications for outcomes of xenotransplantation. We speculate that alterations in glycosylation of vWF and other adhesion proteins associated with the targeting of the alpha1,3-Gal-epitope in mutant swine may have salutatory effects on the primate platelet activation observed in these xenografts.     

Molecular mechanisms in hormone-resistant prostate cancer

Prostate cancer is the most common malignancy in males. Despite the efforts for an early diagnosis, approximately one third of the cases are diagnosed in advanced clinical stages. Prostatic cancer, as the function of normal prostate is dependent upon androgens. So, androgenic deprivation represents an effective treatment especially in advanced cases. Although, the majority of patients will initially respond to androgen blockade, consequently the hormone-resistance will develop and the tumor will progress. The mechanism that determines tumoral progression during the endocrine treatment is driven by genomic instability, characterized by activating mutations of androgen receptor gene (AR), progression of some cellular clones possible of neuroendocrine origin that become adapted to low concentrations of residual adrenal androgens, suppression of apoptosis, by bcl-2 oncogene overexpression and p53 mutations, and growth factors (IGF-1--Insulin-like growth factor, KGF--keratinocyte growth factor, EGF--Epidermal growth factor, TGF a, b- Transforming growth factor a and b, bFGF--Fibroblastic growth factor type b) regulatory effect through either a paracrine or an autocrine mechanism. The identification of molecular alterations that appear during prostate carcinogenesis, may lead to the identification of new molecular targets to prevent hormone-resistance and to improve the prognosis in prostate cancers.     

Synthesis of 2,6-diphenylpyrazine derivatives and their DNA binding and cytotoxic properties

A series of 2,6-diphenylpyrazine derivatives was synthesized from 2,6-dichloropyrazine and 4-methoxyphenylboronic acid using palladium(0) as catalyst in a Suzuki methodology. After deprotection of the hydroxyl, alkylation reactions with different halides afforded compounds 5-8 bearing hydrophilic chains. DNA binding and cytotoxic properties were investigated. Compound 11 bearing imidazoline terminal groups was found to be a potent AT-specific DNA minor groove binder but there was no relationship between DNA interaction and cytotoxicity. However, in all cases the incorporation of the pyrazine ring was found to promote the cytotoxicity of the molecules compared to the corresponding pyridine analogues, previously synthesized.     

The meaning of hospitalization for the pre-school child: a theoretical model

This study was aimed at comprehending the meaning of being hospitalized for pre-school children. The theoretical references were the Symbolic Interactionism and Vygotsky's theory on the child's symbolic play. The methodological referential was the Theory Based on Data. Eleven children between the ages of 3 and 6 took part in the survey. The strategies for data collection were: participative observation, interviews with the children mediated by the Therapeutic Toy, and interviews with the mothers. The analysis of the data made possible the construction of the technical model Growing up with the mother's protective presence, which puts in evidence the vulnerability, the child's force and the protection given by the mother to face the mystery and the fear of hospitalization.     

The mandibular lingula's position in children as a reference to inferior alveolar nerve block

PURPOSE: The objective of this study was to evaluate the position of the mandibular lingula (ML) to provide data for inferior alveolar nerve block techniques in children. METHODS: One hundred fifty-four panoramic radiographs of 7- to 10-year-old boys and girls were analyzed. Measurements were taken from the ML to the occlusal plane, and the percentile distances of the ML to ramal borders were determined. RESULTS: The distance between the ML and the occlusal plane showed a gradual increase, but only in the male group was it statistically significant. ML's ratio position on the ramus remained constant in all analyzed groups. In the 7-year-old group, the ML was observed above the occlusal plane in 70% of girls and 55% of boys. That percentage reached 85% of all children by age 10. CONCLUSIONS: The mandibular lingula's ratio position remained constant. Inferior alveolar anesthesia should be administered at least 6 mm above the occlusal plane in 7- to 8-year-old children, while 10 mm could be indicated for 9- to 10-year-old children. The mandibular lingula should be considered a reliable reference for further studies of inferior alveolar nerve block techniques.