Clinical, dermoscopic and histopathological evaluation of the Meyerson nevus: case report

O nevo de Meyerson ocorre quando uma rara erupção eczematosa focal e transitória surge ao redor de lesões melanocíticas. O mesmo fenômeno também foi observado em lesões não melanocíticas. O caso relatado é o de um doente masculino, 25 anos, que há dois meses notara surgimento de eritema e prurido, circundando dois nevos, localizados no abdome. As lesões eram atípicas à dermatoscopia e procedeu-se à excisão cirúrgica dos dois nevos. O exame histopatológico revelou nevos melanocíticos compostos displásicos, envolvidos por espongiose e vesículas intraepidérmicas. O presente relato sugere que o fenômeno de Meyerson não modifica as características dermatoscópicas dos nevos.Meyerson nevi occur whenever a rare focal and transitory eczematous eruption arises around melanocytic lesions. The same phenomenon has also been observed in non-melanocytic lesions as well. Herein we report the case of a 25 year old, male patient, who had noticed, two months before, the arising of a pruriginous and erithematous halo around two nevi localized on his abdomen. The lesions were found to be atypical on dermoscopic examination and he was submitted to surgical excision of both nevi. Histopathological examination revealed displastic compound melanocytic nevi, surrounded by intraepidermical vesicles and spongiosis. Present report suggests that Meyerson phenomenon does not seem to alter dermoscopic features of nevi

Morphofunctional study of Crab-eating Raccoon (Procyon cancrivorus) mammary gland

Para a descrição macro e microscópica das glândulas mamárias foram utilizadas três fêmeas de Mão Pelada (Procyon cancrivorus). As amostras das glândulas foram processadas conforme técnicas rotineiras para histologia. As fêmeas estudadas apresentaram 3 pares de glândulas mamárias, sendo um par de glândula mamária abdominal cranial, um par de abdominal caudal e um par de inguinal. As papilas mamárias apresentaram formato pendular, como os canídeos domésticos. Microscopicamente, a glândula mamária apresentou da porção externa para a interna: epiderme (epitélio estratificado pavimentoso queratinizado), derme (tecido conjuntivo frouxo e tecido conjuntivo denso não modelado), fibras musculares lisas e ductos papilíferos que abrem em vários ósteos papilares em formato de "chuveiro". A porção secretora glandular era caracteristicamente túbulo alveolar, com células cuboidais dispostas em camada simples. Os resultados indicam que o conjunto glandular estudado é semelhante ao da cadela (Cannis familiaris) tanto em seu aspecto macroscópico quanto em seu aspecto microscópico, este fato sugere que podemos utilizar o Mão Pelada e o Cão como modelos similares de estudo, para identificação de patologias relacionadas a este sistema.Three Procyon cancrivorus females were studied with emphasis for gross and microscopical description of the mammary glands. Samples of the glands were processed with routine techniques for histology. The females studied presented three pairs of mammary glands: one pair of cranial abdominal mammary glands, a second pair of caudal abdominal and a third one, as inguinal mammary glands. Mammary papillae presented a pendulum shape, as in the domestic dogs. Microscopically, the mammary gland consisted from the external to the internal portion (1) of stratified squamous epithelium of the epidermis, (2) dense irregular connective tissue of the derma, and (3) smooth muscle fibers and papillary ducts that flowed with "shower" shape into the lactiferous sinus. The secretory portion consisted of tubule-alveolar glands with cuboidal cells disposed in a simple layer. The results indicate that the set of glandular studies is similar to ones related to dog (Canis familiaris) in such a way in its gross aspect that how much in its microscopically structure. This fact suggests that we can use the raccoon and the dog as similar models of study, for identification of pathologies related to this system.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Combined expression of p20 and p23 proteins from Citrus tristeza virus show enhanced local silencing suppressor activity

Viruses developed a strategy to counter-defence the posttranscriptional gene silencing mechanism (PTGS) based on the activity of silencing suppressor proteins. Citrus tristeza virus (CTV), a member of the genus Closterovirus, has two suppressor proteins (p20 and p23) that target the local RNA silencing response of the host. In GFP transient co-expression assays performed on Nicotiana benthamiana 16C plants, local suppressor activity of p23 and p20 was similar. Co-expression of both proteins from a mild or a stem pitting CTV isolate showed stronger local suppression activity than either suppressor alone, with an increased GFP transcript level six-(for Gp M) to nine-fold (for Gp 3a) higher than non-inoculated 16C plants, in parallel with low accumulation of siRNAs. Further, GFP brightness of leaves infiltrated with Agrobacterium cultures at an OD600 of 0.5 was comparable to those infiltrated with OD600 0.25. These findings indicate that combined action of p20 and p23 proteins results in enhanced suppressor activity

Mitochondrial apoptosis-inducing factor is involved in doxorubicin-induced toxicity on H9c2 cardiomyoblasts

AbstractThe cardiotoxicity induced by the anti-cancer doxorubicin involves increased oxidative stress, disruption of calcium homeostasis and activation of cardiomyocyte death. Nevertheless, antioxidants and caspase inhibitors often show little efficacy in preventing cell death. We hypothesize that a caspase-independent cell death mechanism with the release of the apoptosis-inducing factor from mitochondria is involved in doxorubicin toxicity. To test the hypothesis, H9c2 cardiomyoblasts were used as model for cardiac cells. Our results demonstrate that z-VAD-fmk, a pan-caspase inhibitor, does not prevent doxorubicin toxicity in this cell line. Doxorubicin treatment results in AIF translocation to the nuclei, as confirmed by Western Blotting of cell fractions and confocal microscopy. Also, doxorubicin treatment of H9c2 cardiomyoblasts resulted in the appearance of 50kbp DNA fragments, a hallmark of apoptosis-inducing factor nuclear effects. Apoptosis-inducing factor knockdown using a small-interfering RNA approach in H9c2 cells resulted in a reduction of doxorubicin toxicity, including decreased p53 activation and poly-ADP-ribose-polymerase cleavage. Among the proteases that could be responsible for apoptosis-inducing factor cleavage, doxorubicin decreased calpain activity but increased cathepsin B activation, with inhibition of the latter partly decreasing doxorubicin toxicity. Altogether, the results support that apoptosis-inducing factor release is involved in doxorubicin-induced H9c2 cell death, which explains the limited ability of caspase inhibitors to prevent toxicity

Cymoxanil inhibits respiration through inhibition of mitochondrial complex IV

Cymoxanil is a synthetic acetamide fungicide, used against oomycetes. It was first introduced in 1977 and can be used against downy mildew diseases induced by Plasmopara viticola in grapevine cultures and late blight diseases caused by Phytophthora infestans, in tomatoes and potatoes cultures. This fungicide is used in mixed formulations and its higher solubility enables a relatively widespread occurrence in toxic concentrations in aquatic environments. Although it has been used over the years, its biochemical mode of action is not yet known. Some studies reported that cymoxanil affects growth, respiration, DNA, RNA and protein synthesis and RNA polymerase activity of Phytophthora infestans, and it was reported to inhibit cell growth and biomass production and decrease the respiration rate of S. cerevisiae. Using yeast S. cerevisiae as model, we further characterized its effect on mitochondria. We found that whole cells treated with cymoxanil present a higher inhibition of oxygen consumption after 3 h of treatment that remains over time. Using isolated mitochondria, we observe that cymoxanil inhibits respiratory rate of yeast cells by inhibiting oxidative phosphorylation, through inhibition of complex IV activity. Although other targets cannot be excluded, our data provide new information about mode of action of cymoxanil that can be instrumental to drive informed management regarding the use of this fungicide.info:eu-repo/semantics/publishedVersio

The influence of polysaccharide coating on the physicochemical parameters and cytotoxicity of silica nanoparticles for hydrophilic biomolecules delivery

The present work reports the effect of polysaccharides (chitosan and sodium alginate) on silica nanoparticles (SiNP) for hydrophilic molecules delivery taking insulin as model drug. The influence of tetraethyl orthosilicate (TEOS) and homogenization speed on SiNP properties was assessed by a 22 factorial design achieving as optimal parameters: 0.43 mol/L of TEOS and homogenization speed of 5000 rpm. SiNP mean particle size (Z-Ave) was of 256.6 nm and polydispersity index (PI) of 0.218. SiNP coated with chitosan (SiNP-CH) or sodium alginate (SiNP-SA) increased insulin association efficacy; reaching 84.6% (SiNP-SA) and 90.8% (SiNP-CH). However, coated SiNP released 50%–60% of the peptide during the first 45 min at acidic environment, while uncoated SiNP only released 30%. Similar results were obtained at pH 6.8. The low Akaike’s (AIC) values indicated that drug release followed Peppas model for SiNP-SA and second order for uncoated SiNP and SiNP-CH (pH 2.0). At pH 6.8, the best fitting was Boltzmann for Ins-SiNP. However, SiNP-CH and SiNP-SA showed a first-order behavior. Cytotoxicity of nanoparticles, assessed in Caco-2 and HepG2 cells, showed that 100 to 500 µg/mL SiNP-CH and SiNP-SA slightly decreased cell viability, comparing with SiNP. In conclusion, coating SiNP with selected polysaccharides influenced the nanoparticles physicochemical properties, the insulin release, and the effect of these nanoparticles on cell viability.This research was supported by the Fundação para a Ciência e Tecnologia (FCT, Portugal), by grating PhD scholarships SFRH/BD/60640/2009 (T. Andreani), SFRH/BD/80335/2011 (J.F. Fangueiro) and SFRH/BD/111274/2015 (P.M.V. Fernandes), and funded projects UID/AGR/04033/2019 (CITAB), and M-ERANET/0004/2015-PAIRED (Partnership Agreement PT2020).info:eu-repo/semantics/publishedVersio

Application of hyperthermia induced by superparamagnetic iron oxide nanoparticles in glioma treatment

Gliomas are a group of heterogeneous primary central nervous system (CNS) tumors arising from the glial cells. Malignant gliomas account for a majority of malignant primary CNS tumors and are associated with high morbidity and mortality. Glioblastoma is the most frequent and malignant glioma, and despite the recent advances in diagnosis and new treatment options, its prognosis remains dismal. New opportunities for the development of effective therapies for malignant gliomas are urgently needed. Magnetic hyperthermia (MHT), which consists of heat generation in the region of the tumor through the application of magnetic nanoparticles subjected to an alternating magnetic field (AMF), has shown positive results in both preclinical and clinical assays. The aim of this review is to assess the relevance of hyperthermia induced by magnetic nanoparticles in the treatment of gliomas and to note the possible variations of the technique and its implication on the effectiveness of the treatment. We performed an electronic search in the literature from January 1990 to October 2010, in various databases, and after application of the inclusion criteria we obtained a total of 15 articles. In vitro studies and studies using animal models showed that MHT was effective in the promotion of tumor cell death and reduction of tumor mass or increase in survival. Two clinical studies showed that MHT could be applied safely and with few side effects. Some studies suggested that mechanisms of cell death, such as apoptosis, necrosis, and antitumor immune response were triggered by MHT. Based on these data, we could conclude that MHT proved to be efficient in most of the experiments, and that the improvement of the nanocomposites as well as the AMF equipment might contribute toward establishing MHT as a promising tool in the treatment of malignant gliomas

AVALIAÇÃO DO EFEITO ANTINOCICEPTIVO DE UM GEL DE PIRIDOXINA EM CAMUNDONGOS

Introdução e objetivos: Estudos indicam que vitaminas do complexo B diminuem a resposta nociceptiva pelo aumento do controle inibitório dos neurônios da medula espinhal e pela redução da resposta dos neurônios do tálamo a estimulação nociceptiva. Dados sugerem que as vitaminas do complexo B têm um efeito analgésico na segunda fase do processo inflamatório. Este estudo teve como objetivo avaliar o efeito antinociceptivo de um gel contendo piridoxina (vitamina B6). Metodologia: Camundongos (45 a 55 g) foram divididos em cinco grupos (n=5): controle positivo com indometacina (A), controle negativo (B), gel de piridoxina a 1% (C), a 2% (D) e a 5% (E). Para avaliar o efeito antinociceptivo foi utilizado o modelo do teste de formalina, com contagem do número de lambidas e levantamento da pata traseira de cada um dos animais nos tempos 0 a 5 minutos (dor aguda) e 15 a 30 minutos (dor inflamatória). Resultados e discussões: O grupo A apresentou diminuição da dor inflamatória em relação ao grupo B. Todos os géis contendo piridoxina demonstraram diminuir o segundo estágio da dor (dor inflamatória) em relação ao grupo B, com melhor resposta para a maior concentração de piridoxina (grupo E – 5%). Conclusões: A aplicação tópica de um gel de piridoxina demonstra efeito antinociceptivo em camundongos