Effect of Polishing on the Surface Microhardness of Nanohybrid Composite Resins Subjected to 35% Hydrogen Peroxide: An In vitro Study.

AIM: The use of bleaching agents, despite being a conservative treatment, can cause a decrease in the surface microhardness of dental resins, affecting their aesthetics and performance. The aim of this study was to evaluate the in vitro effect of polishing on the surface microhardness of nanohybrid composite resins that were subjected to bleaching with 35% hydrogen peroxide. MATERIALS AND METHODS: This cross-sectional, in vitro experimental study consisted of 30 composite resin samples made according to ISO 4049-2019 and divided equally into two groups (A and B) which were subjected to 35% hydrogen peroxide bleaching. Group A was subjected to polishing procedure, whereas group B was the control group. The samples were stored in distilled water at 37°C for 24 h. The Vickers microhardness was determined with a load of 100 g-f for 10 s. The data were analyzed with Student's t-test for independent samples at a confidence level of 95%. RESULTS: The surface microhardness of the group that was subjected to polishing (A) obtained a mean of 78.07 ± 7.96 HV, whereas for the group that was not subjected to polishing (B) the mean was 65.67 ± 5.22 HV. The difference between groups (A and B) was statistically significant (P < 0.001). CONCLUSION: Nanohybrid composite resins previously subjected to 35% hydrogen peroxide gel significantly increased their surface microhardness when subjected to polishing when compared with unpolished nanohybrid composite resins.

Grado de microfiltración marginal utilizando adhesivos con técnica grabado total y grabado selectivo del esmalte / Degree of marginal microfiltration using adhesives with etch-and-rinse and selective enamel etching

Objetivos: Comparar in vitro el grado de microfiltración marginal obtenido en las restauraciones de resina compuesta realizadas con la técnica grabado total de tres pasos y con grabado selectivo del esmalte con autograbante de dos pasos. El estudio fue prospectivo, transversal, experimental y comparativo. Material y Métodos: Fueron utilizados 28 premolares, divididos en dos grupos de 14 muestras cada uno a los cuales se les aplicó dos tipos de técnica adhesiva: Un grupo (A) con la técnica grabado total de tres pasos con el sistema adhesivo Optibond FL (Kerr); y grupo (B) con la técnica grabado selectivo del esmalte con autograbante de dos pasos con el sistema adhesivo Optibond XTR (Kerr). Posteriormente obturadas con resina compuesta Filtek Z350 (3M ESPE) y sometidas al proceso de termociclaje durante 500 ciclos de 5°C y 55°C. La microfiltración fue evaluada a través de un índice de profundidad de microfiltración mediante la penetración de azul de metileno al 2 % y observada con microscopio estereoscopio. Resultados: Los datos se analizaron mediante la prueba estadística U de Mann-Whitney, determinándose que no existen diferencias estadísticamente significativas (p≥0,05) entre ambas técnicas adhesivas. Se observó una mayor cantidad de piezas dentarias sin microfiltración en el grupo B (28,6%) sobre el grupo A (7,1 %). Conclusiones: El grado de microlfiltración marginal obtenido en ambas técnicas adhesivas presentó resultados similares.

Objectives: Compare the degree of marginal microfiltration in vitro obtained in composite resin restorations performed with the three-step etch-and-rinse technique and selective enamel etching with two-step self-etch. The study was prospective, transversal, experimental and comparative. Material and Methods: 28 premolars were used, divided into two groups of 14 samples to which were applied two types of adhesive technique: A group (A) with the total three-step etch-and-rinse technique with the Optibond FL (Kerr) adhesive system; and group (B) with selective enamel etching two-step self-etch with the adhesive system Optibond XTR. Later sealed with composite resin Filtek Z350 (3M ESPE) and subjected to the thermocycling process for 500 cycles of 5 ° C and 55 ° C. The microfiltration was evaluated through a depth index of microfiltration through the penetration of 2% methylene blue and observed with stereoscopic microscope. Results: The data were analyzed using the U Mann Whitney test, and it was determined that there were no statistically significant differences (p≥0.05) between the two adhesive techniques. A greater number of teeth without microfiltration was observed in group B (28.6%) over group A (7.1%). Conclusions: The degree of marginal microfiltration obtained in both adhesive techniques presented similar results.

MAD2γ, a novel MAD2 isoform, reduces mitotic arrest and is associated with resistance in testicular germ cell tumors.

BACKGROUND: Prolonged mitotic arrest in response to anti-cancer chemotherapeutics, such as DNA-damaging agents, induces apoptosis, mitotic catastrophe, and senescence. Disruptions in mitotic checkpoints contribute resistance to DNA-damaging agents in cancer. MAD2 has been associated with checkpoint failure and chemotherapy response. In this study, a novel splice variant of MAD2, designated MAD2γ, was identified, and its association with the DNA damage response was investigated. METHODS: Endogenous expression of MAD2γ and full-length MAD2 (MAD2α) was measured using RT-PCR in cancer cell lines, normal foreskin fibroblasts, and tumor samples collected from patients with testicular germ cell tumors (TGCTs). A plasmid expressing MAD2γ was transfected into HCT116 cells, and its intracellular localization and checkpoint function were evaluated according to immunofluorescence and mitotic index. RESULTS: MAD2γ was expressed in several cancer cell lines and non-cancerous fibroblasts. Ectopically expressed MAD2γ localized to the nucleus and reduced the mitotic index, suggesting checkpoint impairment. In patients with TGCTs, the overexpression of endogenous MAD2γ, but not MAD2α, was associated with resistance to cisplatin-based chemotherapy. Likewise, cisplatin induced the overexpression of endogenous MAD2γ, but not MAD2α, in HCT116 cells. CONCLUSIONS: Overexpression of MAD2γ may play a role in checkpoint disruption and is associated with resistance to cisplatin-based chemotherapy in TGCTs.

Methylation of DAPK and THBS1 genes in esophageal gastric-type columnar metaplasia.

AIM: To explore methylation of DAPK, THBS1, CDH-1, and p14 genes, and Helicobacter pylori (H. pylori) status in individuals harboring esophageal columnar metaplasia. METHODS: Distal esophageal mucosal samples obtained by endoscopy and histologically diagnosed as gastric-type (non-specialized) columnar metaplasia, were studied thoroughly. DNA was extracted from paraffin blocks, and methylation status of death-associated protein kinase (DAPK), thrombospondin-1 (THBS1), cadherin-1 (CDH1), and p14 genes, was examined using a methyl-sensitive polymerase chain reaction (MS-PCR) and sodium bisulfite modification protocol. H. pylori cagA status was determined by PCR. RESULTS: In total, 68 subjects (33 females and 35 males), with a mean age of 52 years, were included. H. pylori cagA positive was present in the esophageal gastric-type metaplastic mucosa of 18 individuals. DAPK, THSB1, CDH1, and p14 gene promoters were methylated by MS-PCR in 40 (58.8%), 33 (48.5%), 46 (67.6%), and 23 (33.8%) cases of the 68 esophageal samples. H. pylori status was associated with methylation of DAPK (P = 0.003) and THBS1 (P = 0.019). CONCLUSION: DNA methylation occurs in cases of gastric-type (non-specialized) columnar metaplasia of the esophagus, and this modification is associated with H. pylori cagA positive infection.

Angioqueratoma solitario: reporte de dos casos, características dermatoscópicas y revisión bibliográfica / Solitary angiokeratoma: report of two cases: literature review and dermoscopic features

Los angioqueratomas son lesiones vasculares benignas caracterizadas histológicamente por dilataciones vasculares en la dermis superficial. El angioqueratoma solitario forma parte de las cinco variedades clínicas de Angioqueratomas, se caracteriza por ser único y presentarse en la segunda y tercera década de la vida. Clínicamente es una pápula queratósica, verrucosa rojo azulada de pequeño tamaño. Presenta diversos diagnósticos diferenciales, y el melanoma maligno es el más importante. La dermatoscopia es una herramienta útil para el adecuado diagnóstico de esta patología, respaldada por la histopatología. Se reportan dos casos de pacientes con angioqueratoma solitario y se realiza revisión de la literatura.

The angiokeratomas are histologically bening vascular lesions characterized by vascular dilatación in the superficial dermis. Solitary angiokeratoma is part of the five varieties angiokeratomas clinical features and be unique in the second and third decades of life. Clinically, it is a keratotic, warty, small red blue to back popule. Presents various differential diagnoses being malignant melanoma principal. dermoscopy is a helpful tool for the proper diagnosis of this disease, supported by histopathology. We report two cases of patients with solitary angiokeratoma and literature review was performed.

Differential distribution of HP1 proteins after trichostatin a treatment influences chromosomal stability in HCT116 and WI-38 cells.

BACKGROUND: Heterochromatin protein 1 (HP1) is important in the establishment, propagation, and maintenance of constitutive heterochromatin, especially at the pericentromeric region. HP1 might participate in recruiting and directing Mis12 to the centromere during interphase, and HP1 disruption or abrogation might lead to the loss of Mis12 incorporation into the kinetochore. Therefore, the centromere structure and kinetochore relaxation that are promoted in the absence of Mis12 could further induce chromosome instability (CIN) by reducing the capacity of the kinetochore to anchor microtubules. The aim of this study was to determine whether alterations in the localization of HP1 proteins induced by trichostatin A (TSA) modify Mis12 and Centromere Protein A (CENP-A) recruitment to the centromere and whether changes in the expression of HP1 proteins and H3K9 methylation at centromeric chromatin increase CIN in HCT116 and WI-38 cells. METHODS: HCT116 and WI-38 cells were cultured and treated with TSA to evaluate CIN after 24 and 48 h of exposure. Immunofluorescence, Western blot, ChIP, and RT-PCR assays were performed in both cell lines to evaluate the localization and abundance of HP1α/ß, Mis12, and CENP-A and to evaluate chromatin modifications during interphase and mitosis, as well as after 24 and 48 h of TSA treatment. RESULTS: Our results show that the TSA-induced reduction in heterochromatic histone marks on centromeric chromatin reduced HP1 at the centromere in the non-tumoral WI-38 cells and that this reduction was associated with cell cycle arrest and CIN. However, in HCT116 cells, HP1 proteins, together with MIS12 and CENP-A, relocated to centromeric chromatin in response to TSA treatment, even after H3K9me3 depletion in the centromeric nucleosomes. The enrichment of HP1 and the loss of H3K9me3 were associated with an increase in CIN, suggesting a response mechanism at centromeric and pericentromeric chromatin that augments the presence of HP1 proteins in those regions, possibly ensuring chromosome segregation despite serious CIN. Our results provide new insight into the epigenetic landscape of centromeric chromatin and the role of HP1 proteins in CIN.

The MAD1 1673 G → A polymorphism alters the function of the mitotic spindle assembly checkpoint and is associated with a worse response to induction chemotherapy and sensitivity to treatment in patients with advanced epithelial ovarian cancer.

BACKGROUND: Mitotic arrest deficient 1 (MAD1), a protein of the mitotic spindle assembly checkpoint (SAC), recognizes MAD2 through two leucine zippers, transporting and activating MAD2, which promotes a metaphase arrest signal. A single nucleotide polymorphism of MAD1 was found to affect the SAC function that could be involved in a poor response to therapeutic agents that alter the dynamics of microtubules. OBJECTIVE: The aim of this study was to examine the relationship of the polymorphism MAD1 1673 G → A (rs1801368) with the efficiency of the SAC and the generation of aneuploidies and with the therapeutic response of patients with ovarian cancer. METHODS: The polymorphism was evaluated in 144 healthy individuals and 91 patients. Mitotic arrest and the presence of errors in segregation were analyzed in cultured human lymphocytes treated with nocodazole and paclitaxel. Errors in segregation were also evaluated in 27 biopsies of patients. RESULTS: Allele frequencies in healthy individuals were G: 50%, A: 50%, whereas in the patients they were G: 38%, A: 62% (P<0.05). The percentage of cells with mitotic arrest was higher among GG cells (P<0.05). The frequency of micronuclei and nondisjunction events increased in AA cells (P<0.05). Tumors from polymorphic patients had a higher percentage of aneuploid cells (P<0.05). The GG patients showed a higher biochemical response, optimal cytoreduction, and sensitivity to the treatment. There were no differences in progression-free or overall survival between both groups. CONCLUSION: The polymorphism MAD1 1673 G → A affects SAC functionality, increasing the frequency of aneuploid cells. This polymorphism modifies the response to agents that alter the dynamics of microtubules in patients with ovarian cancer.

NF-kappaB does not influence the induction of apoptosis by Ukrain.

Ukrain is a reaction product of different alkaloids from Chelidonium majus L. (celandine) conjugated with thiophosphoric acid. It has immunoregulatory effects on T lymphocyte subsets and cytotoxic and cytostatic effects on various malignant cells. Although Ukrain has been reported to induce alterations in the cell cycle and tubulin polymerization, the specific cellular target has not been described. Since antineoplasic agents induce NF-kappaB and their effects are regulated by this transcription factor, we investigated its possible participation in the apoptotic effects of Ukrain. Ukrain induced apoptosis in a panel of cancer cell lines by activating the intrinsic cell death pathway, as demonstrated by the cleavage of caspase 9 and the upregulation and cleavage of caspase 3. The effect was reversible, since long exposures (24 hours or more) were needed, as verified by clonogenic assays. Gene reporter assays showed that Ukrain activated NF-kappa B. Nevertheless, this activation was not required for, and did not modulate, the Ukrain effect: neither blockage of activation by a dominant negative version of Ikappa-B alpha or a Bcl-3 siRNA, nor activation of the pathway by overexpression of IKK2, changed the response to the drug. In conclusion, Ukrain induced apoptosis in HeLa cervical cancer cells by activating the intrinsic pathway. In contrast to other antineoplasic drugs, the effects of Ukrain were not regulated by NF-kappa B.

Angioma serpiginoso / Angioma serpiginosum

El angioma serpiginoso es un desorden vascular benigno, crónico y progresivo caracterizado por presentar máculas rojo vinosas purpúricas, de aspecto serpiginoso, distribuidas sobre la superficie de la piel producido por una ectasia de los vasos sanguíneos cutáneos de la dermis superficial. Las lesiones generalmente son asintomáticas, progresan lentamente, particularmente durante los primeros años, estabilizándose después. Es posible la involución espontánea. Presentamos tres casos de angioma serpiginoso y se hace una revisión del tema.

Granulosis rubra nasi / Granulosis rubra nasi

La granulosis rubra nasi es una dermatosis inflamatoria eritémato-papular pruriginosa que compromete las glándulas ecrinas de la nariz, mejilla y barbilla, de etiología incierta, poco frecuente, de curso crónico, y naturaleza benigna; caracterizado clínicamente por la presencia de pápulas eritematosas e hiperhidrosis persistente en la punta de nariz. Se presenta con mayor frecuencia en la niñez temprana y es de resolución espontánea en la adolescencia. El tratamiento es sintomático y cosmético, sin embargo el uso de corticoides tópicos de baja potencia producen una mejoría. Presentamos el caso de un paciente varón de 10 años de edad con hiperhidrosis y lesiones papulares eritematosas localizadas en la dermis e infiltrado inflamatorio alrededor de los ductos sudoríparos ecrinos: Se instituyó tratamiento con corticoides no fluorados, observándose mejoría. Se debe considerar a la granulosis rubra nasi como diagnóstico diferencial de las lesiones pápulo-eritematosas de la cara sobre todo en pacientes de edad pediátrica.

Morfea lineal / Linear morphea

La Morfea Lineal es una variedad de esclerodermia localizada de curso crónico y origen desconocido es relativamente frecuente en niños y se caracteriza por esclerosis del comportamiento cutáneo y cambios pigmentarios que adoptan una distribución lineal, comprometiendo con frecuencia planos subyacentes. En este artículo reportamos a una niña de 6 años de edad quien inicia su cuadro a los dos años con eritema, dolor y prurito en dorso de pie derecho, evolucionando a la ulceración con posterior cicatrización y fibrosis, la cual avanza comprometiendo planos profundos y cursando retracción de los dedos por compromiso tendinoso. El estudio histológico mostró incremento y condensación de tejido conectivo con edema, homogenización, fibrosis y esclerosis del colágneo. La paciente recibió corticoides intralesionales obteniéndose la detención del cuadro. El tratamiento de elección en este tipo de patología aún no está definido, empleándose en la actualidad corticoides tópicos, calcipotriene tópico y terapias sistémicas que van desde los controversiales corticoides hasta calcitriol, retinoides, inmunomodulares y la fototerapia.

Tratamiento y reinfestación por escabiosis humana: estudio comparativo entre permetrina al 5 por ciento vs benzoato de bencilo al 25 por ciento / Treatment and reinfestation by human scabiosis: comparative study between 5 percentage permetrin and 25 percentage bencyl benzoate

La Escabiosis es una infestación de la piel producida por el Sarcoptes scabiei variedad humana, ácaro que cursa con recidivas y es muy común en nuestro medio, motivo por el cual se realizó un estudio comparativo de Permetrina al 5 por ciento versus Benzoato de Bencilo al 25 por ciento determinándose el índice de recidivas post tratamiento. Se incluyeron en el estudio 60 pacientes mayores de 2 años. 30 pacientes recibieron Permetrina al 5 por ciento y los otros 30 Benzoato de bencilo al 25 por ciento. Los resultados demostraron eficacia en el tratamiento de la escabiosis tanto para la Permetrina al 5 por ciento como para el Benzoato de bencilo al 25 por ciento. No se observaron reinfestaciones en un periodo de 4 a 6 meses en los pacientes tratados con Permetrina al 5 por ciento a pesar que regresaron a su entorno sin las medidas preventivas indicadas para evitar recaidas; lo que si se observó en los pacientes que usaron Benzoato de bencilo al 25 por ciento, quienes bajo las mismas condiciones presentaron reinfestaciones a los 10 días de haber concluido el tratamiento. Este estudio demuestra que la Permetrina al 5 por ciento proporciona períodos mas prolongados de protección contra la reinfestación comparado con el Benzoato de bencilo al 25 por ciento.

Hiperplasia angiolinfoide con eosinofilia / Angiolinphoid hyperplasia with eosinophilia

La hiperplasia angiolinfoide con eosinofilia (HAE) es un desorden vascular benigno, poco frecuente, de etiología desconocida, curso crónico caracterizado por la proliferación de células endoteliales asociada a intenso infiltrado inflamatorio de linfocitos, histiocitos y numerosos eosinófilos. Manifestándose clínicamente por pápulas y nódulos de aspecto angiomatoso en piel y tejido celular subcutáneo de cabeza y cuello. Presentamos el caso de un paciente varón de 23 años con lesiones localizadas en el lóbulo de la oreja izquierda y pabellón auricular derecho. Se indicó tratamiento con Pentoxifilina, después de no obtener un buen resultado con cirugía y criocirugía, obteniendo una buena respuesta.

Fotoprotectores tópicos / Tropical photoprotectors

Hacemos una revisión sobre fotoprotectores tópicos, señalando los conceptos más importantes que el dermatólogo debe tener en cuenta en la práctica diaria para prescribir estos productos; haciendo énfasis en el significado del Factor de Protección Solar (FPS), espectro de acción, clasificación de fotoprotectores; finalmente se realizan recomendaciones básicas para la correcta eleccción y uso del fotoprotector.