Biomateriales que inducen la remineralización del esmalte dental y dentina / Biomaterials that induce remineralization of the dentin and enamel surface

Desde los sesentas, con la invención del vidrio bioactivo, los tratamientos de remineralización se han popularizado entre los cirujanos dentistas y su utilización es cada vez mayor; la remineralización, en conjunto con las adecuadas medidas de higiene preventiva, representa uno de los mejores abordajes mínimamente invasivos y a un costo comparativamente bajo. Este estudio documental tiene por objetivo establecer una mejor comprensión del uso clínico de los biomateriales que inducen la remineralización de la superficie del esmalte dental y dentina. Se realizó una exploración utilizando motores de búsqueda (bases de datos en PubMed, Medigraphic, y Science Direct). El proceso de localización de los estudios relevantes se efectuó introduciendo palabras clave como: silicatos de calcio, fosfopéptidos de caseína-fosfato de calcio amorfo, remineralización, esmalte y dentina, incluyéndose en el procedimiento artículos de antigüedad no superior a siete años, en español e inglés, publicados en revistas científicas aprobadas por pares.Actualmente, no es posible remineralizar del todo la estructura dentaria, por lo cual, en un futuro cercano, los esfuerzos de la odontología de remineralización deben apuntar al desarrollo de agentes biomiméticos inteligentes que restauren al cien por ciento la estructura dental perdida (AU)

Since the sixties, with the invention of bioactive glass, remineralization treatments have become popular among dental surgeons. Their usage is increasing; remineralization, in conjunction with appropriate preventive hygiene measures, represents one of the best minimally invasive treatments at a relatively low cost. This documentary study aims to establish a better understanding of the clinical use of biomaterials that induce remineralization of the surface of teeth enamel and dentin. A search was conducted using search engines (PubMed and Medigraphic databases, and Science Direct). The search process for the relevant studies was carried out by introducing keywords such as calcium silicates, phosphopeptides of amorphous calcium casein-phosphate, remineralization, enamel and dentin, including in the search articles no older than seven years in Spanish and English published in scientific reviewed journals. Currently, it is not possible to completely remineralize the dentary structure so, in the near future, remineralization dentistry efforts should aim to develop (AU)

Casein phosphopeptide-amorphous calcium phosphate nanocomplex (CPP-ACP) in dentistry: state of the art / Nanocomplejo de fosfopéptido de caseína-fosfato de calcio amorfo (CPP-ACP) en Odontología: estado del arte

ABSTRACT Saliva and external agents containing different concentrations of sodium fluoride (NaF) promote the dental remineralization process. However, these resources may not be sufficient to counteract the multiple factors involved in the process of dental caries, especially in high-risk patients. There are alternatives that have been extensively researched, such as casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) which provides essential ions, like phosphate and calcium, acting as an adjuvant in the remineralization process. Manufacturers of CPP-ACP-based products also suggest that it can produce desensitizing effects. This nanocomplex has been used experimentally with some dental cements and adhesive systems, but it is important to clarify the effects of this procedure, and the remineralizing/desensitizing advantages it offers. The objective of this topic review was to present the state of the art on CPP-ACP nanocomplex. In terms of dental caries prevention, this remineralizing option is not better than NaF. CPP-ACP provides a dental desensitizing action, but it is temporary, similar or less effective than other alternatives such as potassium nitrate or NaF. The experimental incorporation of CPP-ACP into dental cements should be controlled for not to compromise the physico-chemical properties of the material. The use of dental products based on this nanocomplex as dental surface pretreatment may decrease the bond strength of adhesive materials, but this effect is material dependent.

RESUMEN La saliva y agentes externos que contienen diferentes concentraciones de fluoruro de sodio (NaF) favorecen el proceso de remineralización dental. No obstante, estos recursos podrían no ser suficientes para contrarrestar los múltiples factores involucrados en el proceso de caries dental, especialmente en pacientes con alto riesgo. Existen alternativas que han sido ampliamente investigadas, como el fosfopéptido de caseína-fosfato de calcio amorfo (CPP-ACP) que aporta iones esenciales como fosfato y calcio, actuando como coadyuvante en el proceso de remineralización. Los fabricantes de productos basados en CPP-ACP también sugieren que este es capaz de generar efectos desensibilizantes. Este nanocomplejo ha sido utilizado de forma experimental con algunos cementos dentales y sistemas adhesivos, pero es importante esclarecer los efectos de dicha incorporación y las ventajas remineralizantes/desensibilizantes que ofrece esta alternativa. El objetivo del presente artículo de revisión de tema consistió en presentar el estado del arte sobre el nanocomplejo CPP-ACP. En términos de prevención de caries dental, esta opción remineralizante no es superior al NaF. El nanocomplejo ejerce acción desensibilizante dental, pero esta es transitoria, similar o inferior a otras alternativas como nitrato de potasio o NaF. La incorporación experimental de CPP-ACP en cementos dentales debe ser controlada para no comprometer las propiedades fisicoquímicas del material. La utilización de productos dentales a base de este nanocomplejo como pretratamiento de la superficie dental puede disminuir la resistencia de unión de materiales adhesivos, pero este efecto es material-dependiente.

An in Vitro Evaluation of Remineralizing Capacity of Self-Assembling Peptide (SAP) P11-4 and Casein Phosphopeptides-Amorphous Calcium Phosphate (CPP-ACP) on Artificial Enamel

Objective: To determine and compare the remineralizing capacity of self-assembling peptide (SAP) P11-4 and casein phosphopeptides­amorphous calcium phosphate (CPP-ACP) on enamel. Material and Methods: Enamel samples were divided into 2 groups. Group I was treated with Self­assembling peptide (SAP) P11-4 and group II with casein phosphopeptides-amorphous calcium phosphate (CPP-ACP). In both groups, remineralizing capacity was assessed at baseline, 2 weeks, 6 weeks and 12 weeks. Student's t- test and ANOVA were applied, with the significance level set at 5%. Results: The mean calcium weight % was evaluated at baseline, 2 weeks, 6 weeks and 12 weeks. In Group I, there was increase in mean value (62.12 ± 1.24) from baseline to 12 weeks (67.36 ± 2.14). However, there was decrease in phosphate weight % from 37.16 ± 2.52 at baseline to 35.72 ± 2.11 at 12 weeks. In Group II, mean calcium weight % was 64.18 ± 1.52 at baseline, which ultimately increased to 66.01 ± 2.03 at 12 weeks. Phosphate weight % showed reduction from 37.34 ± 2.23 at baseline to 35.04 ± 2.02 at 12 weeks. Ca/P ratio showed significant improvement. There was significant difference in Ca/P ratio at 2 weeks, 6 weeks and 12 weeks in both groups (p<0.05). Conclusion: Self-assembling peptide (SAP) P11-4 found to be more effective and efficient as compared to casein phosphopeptides­amorphous calcium phosphate (CPP-ACP).

Displacers improve the selectivity of phosphopeptide enrichment by metal oxide affinity chromatography / Uso de desplazadores para mejorar la selectividad de los fosfopéptidos enriquecidos por cromatografía de afinidad con óxidos de metales

Abstract: Background: A key process in cell regulation is protein phosphorylation, which is catalyzed by protein kinases and phosphatases. However, phosphoproteomics studies are difficult because of the complexity of protein phosphorylation and the number of phosphorylation sites. Methods: We describe an efficient approach analyzing phosphopeptides in single, separated protein by two-dimensional gel electrophoresis. In this method, a titanium oxide (TiO2)-packed NuTip is used as a phosphopeptide trap, together with displacers as lactic acid in the loading buffer to increase the efficiency of the interaction between TiO2 and phosphorylated peptides. Results: The results were obtained from the comparison of mass spectra of proteolytic peptides of proteins with a matrix-assisted laser desorption-ionization-time of flight (MALDI-TOF) instrument. Conclusions: This method has been applied to identifying phosphoproteins involved in the symbiosis Rhizobium etli-Phaseolus vulgaris.

Resumen: Introducción: Un proceso clave en la regulación celular es la fosforilación de proteínas, que se lleva a cabo por cinasas y fosfatasas. Sin embargo, los estudios de fosfoproteómica son difíciles debido a la complejidad de la fosforilación proteica y el número de sitios de fosforilación. Métodos: En el presente trabajo se describe una eficiente estrategia metodológica para analizar fosfopéptidos de proteínas separadas mediante electroforesis bidimensional. En este método, una columna con microesferas de dióxido de titanio (TiO2/NuTip) se utilizó para atrapar los fosfopéptidos en la superficie del TiO2 previamente empacado en una punta. El uso de desplazadores en el buffer de carga, como el ácido láctico, mejoró significativamente la selectividad. Resultados: Los resultados se obtuvieron mediante la comparación de los espectros de masas de péptidos proteolíticos de proteínas analizados utilizando un instrumento de desorción/ionización láser asistida por matriz-tiempo de vuelo (MALDI-TOF). Conclusiones: Este método se ha aplicado para la identificación de fosfoproteínas involucradas en la simbiosis del Rhizobium etli con Phaseolus vulgaris.

Comparison of mineral density in molar incisor hypomineralization applying fluoride varnishes and casein phosphopeptide-amorphous calcium phosphate

The aim of the present work was to evaluate and compare variations in mineral density (MD) using laserinduced fluorescence (LF) after applying 5% Sodium Fluoride Varnish (Duraphat®), 5% Sodium Fluoride Varnish with Tricalcium Phosphate (Clinpro®) or Casein phosphopeptideamorphous calcium phosphate (Recaldent®) on teeth with Molar Incisor Hypomineralization (MIH). Mineral density of 92 MIH teeth with mild (Mi) and moderate (Mo) lesions was assessed using a DIAGNOdent device (KaVo, Biberach, Germany). LF values were recorded on day 0 (baseline) and on days 15, 30 and 45; the remineralizing agents were applied immediately after LF readings at baseline and on days 15 and 30. Data corresponding to Mi and Mo lesions were analyzed separately. Significant differences were observed both in mild (p<0.01) and moderate (p<0.000005) lesions. Differences between Recaldent® and Clinpro®, and between Duraphat® and Clinpro® (global level 0.10) were found in Mi lesions. All 3 pairs of products differed significantly in Mo lesions (global level 0.05). The results obtained under the conditions used here allow concluding that Clinpro® was more effective in mild lesions whereas Duraphat® was more effective in moderate lesions (AU)

El objetivo del trabajo fue evaluar y comparar la variación de la densidad mineral (MD) registrada con láser de fluorescencia (LF), posteriormente a la aplicación de barniz fluorado al 5% (Duraphat®), barniz fluorado al 5% con fosfato tricálcico (Clinpro®) y fosfopéptidos de caseínafosfato de calcio amorfo (Recaldent®) en piezas con Hipomineralización Molar Incisiva (MIH). La MD de 92 piezas dentarias con MIH con lesiones leves (Mi) y moderadas (Mo) fue registrada utilizando el equipo DIAGNOdent (KaVo, Biberach, Germany). Los valores de LF fueron registrados en el día 0 (condiciones basales) y en los días 15, 30 y 45. Los agentes remineralizantes fueron aplicados inmediatamente luego de los registros de LF en condiciones basales y en los días 15 y 30. A los 45 días se observaron diferencias significativas tanto en las lesiones leves (p<0,01) como en las moderadas (p<0,000005). En las lesiones leves se detectaron diferencias significativas entre los productos Recaldent® y Clinpro® y entre Duraphat® y Clinpro® a nivel global 0,10. En las lesiones moderadas los tres pares de productos resultaron significativamente diferentes a nivel global 0,05. Los resultados obtenidos permiten concluir que, en las condiciones de este estudio, Clinpro® resultó más efectivo en lesiones leves, mientras que Duraphat® lo fue en lesiones moderadas (AU)

A phosphorylation pattern-recognizing antibody specifically reacts to RNA polymerase II bound to exons

The C-terminal domain of RNA polymerase II is an unusual series of repeated residues appended to the C-terminus of the largest subunit and serves as a flexible binding scaffold for numerous nuclear factors. The binding of these factors is determined by the phosphorylation patterns on the repeats in the domain. In this study, we generated a synthetic antibody library by replacing the third heavy chain complementarity-determining region of an anti-HER2 (human epidermal growth factor receptor 2) antibody (trastuzumab) with artificial sequences of 7–18 amino-acid residues. From this library, antibodies were selected that were specific to serine phosphopeptides that represent typical phosphorylation patterns on the functional unit (YSPTSPS)₂ of the RNA polymerase II C-terminal domain (CTD). Antibody clones pCTD-1stS2 and pCTD-2ndS2 showed specificity for peptides with phosphoserine at the second residues of the first or second heptamer repeat, respectively. Additional clones specifically reacted to peptides with phosphoserine at the fifth serine of the first repeat (pCTD-1stS5), the seventh residue of the first repeat and fifth residue of the second repeat (pCTD-S7S5) or the seventh residue of either the first or second repeat (pCTD-S7). All of these antibody clones successfully reacted to RNA polymerase II in immunoblot analysis. Interestingly, pCTD-2ndS2 precipitated predominately RNA polymerase II from the exonic regions of genes in genome-wide chromatin immunoprecipitation sequencing analysis, which suggests that the phosphoserine at the second residue of the second repeat of the functional unit (YSPTSPS)2 is a mediator of exon definition.

Qualidade físico-química e atividades biológicas de caseinofosfopeptídeos obtidos por hidrólise tríptica de caseinato de sódio sob diferentes condições / Physico-chemical quality and biological activities of Casein phosphopeptides obtained by sodium caseinate tryptic hydrolysis under different conditions

Muitos métodos têm sido empregados na produção de peptídeos bioativos para a promoção da saúde. O objetivo deste estudo foi produzir caseinofosfopeptídeos por hidrólise tríptica do caseinato de sódio usando diferentes temperaturas (37 e 50 °C) e tempos de reação (2 e 4 h), caracterizá-los e analisar sua influência nas atividades citotóxica, antimicrobiana e antioxidante. Caseinofosfopeptídeos foram caracterizados através da composição centesimal, eletroforese em gel de poliacrilamida, Espectrometria de Massas e Cromatografia Líquida de Alta Eficiência. Toxicidade para leucócitos humanos, atividade antimicrobiana utilizando o teste de microdiluição em caldo e determinação da capacidade antioxidante pelo método de espécies reativas ao ácido tiobarbitúrico foram os ensaios biológicos realizados. Os resultados mostraram que as quatro frações peptídicas obtidas apresentaram-se com baixo peso molecular e elevados teores proteico e mineral; quanto ao perfil aminoacídico, apresentaram elevadas e diferenciadas quantidades de ácido glutâmico e serina, que pouco variaram de acordo com o processo de obtenção; não se mostraram tóxicos para leucócitos humanos; demonstraram atividade antimicrobiana para Escherichia coli e Salmonella Enteritidis e elevada capacidade antioxidante. Os resultados físico-químicos das frações de caseinofosfopeptídeos demonstraram elevada composição nutricional em termos de proteína e, principalmente, cálcio. O conjunto de dados indicou que alterações no tempo e na temperatura de reação para a obtenção dos hidrolisados não interferem nas suas qualidades biológicas, mostrando serem seguros para a promoção da saúde e para a aplicação em situações especiais, que envolvem pacientes desnutridos, imunossuprimidos, com comprometimento ósseo ou gastrintestinal decorrentes de inflamações e infecções.

Several methods have been employed for the production of bioactive peptides for health promotion. The aim of this study was to produce and characterize Casein phosphopeptides obtained by sodium caseinate tryptic hydrolysis under different temperatures (37 and 50 °C) and reaction times (2 and 4 h), and evaluate their biological capabilities. They have been characterized by assessing their centesimal composition, by polyacrylamide gel electrophoresis, Mass Spectrometry, and High-Performance Liquid Chromatography. The biological activities tested included toxicity for human leukocytes, antimicrobial assay using the microdilution test, and determination of the antioxidant capacity by the thiobarbituric acid reactive species method. The results showed that the four fractions obtained were of low molecular weight with high protein and mineral contents; their amino acid profile showed high and differentiated amounts of glutamic acid and serine independent of the methodological procedures. The results also showed no toxicity for human peripheral leukocytes, demonstrated antimicrobial activity against Escherichia coli and Salmonella Enteritidis as well as high antioxidant capacity. The results of the physicochemical Casein phosphopeptides' fractions showed high nutritional composition in terms of protein and, particularly, calcium. The biological assays indicated that time and temperature changes in the process for obtaining casein hydrolysates have not interfered with their biological qualities. In addition, they have proven safe in promoting health in special conditions involving malnourished and/or, immunocompromised patients or those with bone and/or gastrointestinal impairment due to inflammations and infections.

Association of junk food consumption with high blood pressure and obesity in Iranian children and adolescents: the CASPIAN-IV Study / Associação entre o consumo de junk food e a pressão arterial alta e obesidade em crianças e adolescentes iranianos: o Estudo Caspian-IV

OBJECTIVE: This study aimed to evaluate the association of junk food consumption with hypertension and obesity in a national sample of Iranian children and adolescents. METHODS: This nationwide study was conducted in 2011-2012 among 14,880 students, aged 6-18 years, selected by cluster sampling from 30 provinces. Weight, height, waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), as well as systolic and diastolic blood pressure (BP) were measured. Junk food was divided into four categories, including salty snacks, sweets, sweetened beverages, and fast food. Subjects reported how many times they had consumed each item (daily, weekly, and seldom). RESULTS: The intake of sweets was significantly associated with anthropometric indices and BP levels. Moreover, a significant association was found between fast food consumption, BP levels, and anthropometric indices (except for WHtR and WHR). Sweet beverages consumption was significantly associated with anthropometric indices; however, the consumption of salty snacks was only significantly associated with height, HC, and WHR. The risk of general obesity (OR: 0.75, 95% CI: 0.65-0.87) and abdominal obesity (OR: 0.81, 95% CI: 0.72-0.92) among participants who seldom consumed sweets was less than those who consumed daily. Also, the risk of general obesity (OR: 0.85, 95% CI: 0.74-0.97) among students that seldom consumed sweetened beverages was less than subjects who consumed them on a daily basis. CONCLUSION: It was found that junk food consumption increased the risk of both general and abdominal obesity; therefore, consumption of junk food should be reduced via restricting TV advertisements and increasing taxes on junk foods. .

OBJETIVO: Avaliar a associação entre o consumo de junk food e a hipertensão e obesidade em uma amostra nacional de crianças e adolescentes iranianos. MÉTODOS: Este estudo nacional foi feito entre 2011 e 2012 com 14.880 estudantes com seis-18 anos, selecionados por amostra em bloco em 30 províncias. Foram medidos o peso, a estatura, a circunferência da cintura (CC), a circunferência do quadril (CQ), a razão cintura/quadril (RCQ), a razão cintura/estatura (RCE) e a pressão arterial sistólica e diastólica (PAS e PAD). A junk food foi dividida em quatro categorias, incluindo lanches salgados, doces, bebidas açucaradas e fast food. Os indivíduos relataram quantas vezes consumiam cada um dos itens (diariamente, semanalmente, raramente). RESULTADOS: O consumo de doces foi associado significativamente aos índices antropométricos e níveis de pressão arterial (PA). Além disso, havia uma associação significativa entre o consumo de fast food e os níveis de PA e os índices antropométricos (exceto RCE e RCQ). O consumo de bebidas açucaradas foi associado significativamente aos índices antropométricos, porém o consumo de lanches salgados foi associado significativamente apenas a estatura, CQ e RCQ. O risco de obesidade geral (RC: 0,75, IC de 95%: 0,65-0,87) e obesidade abdominal (RC: 0,81, IC de 95%: 0,72-0,92) entre participantes que raramente consumiam doces era menor do que naqueles que os consumiam diariamente. Além disso, o risco de obesidade geral (RC: 0,85; IC de 95%: 0,74-0,97) entre estudantes que raramente consumiam bebidas açucaradas era menor do que entre indivíduos que os consumiam diariamente. CONCLUSÃO: Constatamos que o consumo de junk food aumentou o risco de obesidade geral e abdominal; portanto, o consumo de junk food deve ser reduzido por meio da restrição de comerciais de TV e do aumento de impostos sobre esse tipo de alimento. .

Healthy lookig hospital nurses showing vitamin D deficiency: correlation of vitamin D levels with their levels of parathyroid hormone and bone turnover markers

To evaluate the correlation of low vitamin D levels with parathyroid hormone [PTH] levels and bone turn over markers among apparently healthy hospital nurses. Screening was done on 50 recruited healthy female nursing staff, aged between 18 to 35 years, for vitamin D levels. Among them 31 were found to be deficient in vitamin D. These 31 nurses were selected for further evaluation in trance. Their vitamin D levels were calculated by using the electrochemiluminescence immunoassay. Blood samples were drawn to estimate serum PTH levels accordingly. Samples were also collected from these recruited subjects to evaluate their bone turn over markers, including, osteocalcin, procollagen type 1 N propeptide and Beta-Crosslaps. Out of 50 subjects, 31 subjects were found to have Vitamin D levels below 50 nmol/l. Out of these 31 subjects, 13 subjects, 41.9%, showed vitamin D levels below 20 nmol/l. Among these 13 subjects, all had significantly raised PTH levels [p-value: <0.001, r-value: -0.781]. In rest of all the subjects, including those having Vitamin D levels above 20nmol/l, inordinately, PTH levels were normal. No reciprocity was found between low Vitamin D and raised M'H levels with bone turnover markers, except with PlNP [r-value 0.022]. PTH levels show a steep augmentation in serum, when vitamin D levels ht the trough below 20 nmol/l. These are the subjects who should be treated prior to the development of complications of bone resorption. Moreover we could not find any significant correlation of Vitamin D and PTH with any bone turnover marker except PlNP

Progress and application of phosphoproteomics in the proteomics of liver pathological and physiological state / 生物工程学报

The phosphorylation is one of most common protein post-translational modifications. The protein phosphorylation plays important roles in the life through the reversible process of phosphorylation and dephosphorylation by kinases and phosphatases. Systematical analysis of the phosphorylation state of proteins would greatly help to reveal the mystery of the life. Recently, with the development of mass spectrometer, bioinformatics sortwares and enrichment methods of phosphopeptides, phosphorylation stduy of orgnism proteins by mass spectrometer has become mature gradually. Liver is one of the most important metabolic and immune organs. In-depth study of protein phosphorylation in liver is of great importance to reveal its function. And booming phosphoproteomics has been applied into the study of liver, which has deepened the knowledge of molecular mechnism of its physiology and pathology states. Here, we review the recent progress on the research and development of phosphoproteomics and their application in liver proteomics study.

Mousse dentário: fosfopeptídeo de caseína estabilizado fosfato de cálcio amorfo CPP-ACP - novas opções de tratamento / Tooth mousse: casein fosfopeptid stabilized by amorphous calcium phosphate CPP-ACP - new options of dental treatment

O fosfopeptídeo de caseína estabilizado fosfato de cálcio amorfo (CPP-ACP – tooth mousse) é uma nova tecnologia de prevenção, que foi desenvolvida para a estabilização do cálcio e do fosfato no leite. A caseína contém uma sequência de aminoácidos que interagem com o cálcio, fosfato e íons fluoretos na solução, para estabilizar e impedir a sua transformação em fases cristalinas. Estes complexos estabilizados podem ser purificados, em forma de pó, sendo então adicionados a uma variedade de veículos, tais como creme dentais, gomas de mascar e pastilhas sem açúcar. O CPP-ACP pode ser usado em uma variedade de situações clínicas para ajudar a inibir a progressão da doença cárie, promovendo a remineralização onde houve perda de minerais e em outras aplicações, tais como a mineralização pós-eruptiva e lesões hipomineralizadas, assim como no tratamento de hipersensibilidade dentinária.

Effect of casein phosphopeptide-amorphous calcium phosphate on the stability of resin-dentin bonds against pH cycling / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on the stability of resin-dentin bonds against pH cycling.</p><p><b>METHODS</b>Resin-bonded dentin specimens were prepared following manufacturers' instructions, and randomly divided into 3 groups. Among them, 2 groups experienced pH cycling, in which specimens applied CPP-ACP or distilled and deionized water (DDW) on the bonding interface, respectively. Microtensile bond strength (muTBS) testing, failure mode analysis, micromorphological and nanoleakage evaluation of bonding interface and elemental analysis within hybrid layer were performed after 15 days pH cycling. The other group was tested immediately after specimens' preparation without pH cycling.</p><p><b>RESULTS</b>No significant differences were found in muTBS between no pH cycling and pH cycling/CPP-ACP group. Their muTBS were both significantly higher than that of pH cycling/DDW group (P < 0.05). Mixed fractures were the most prevalent failure mode. The quality of hybrid layer in pH cycling/CPP-ACP group was better than that of pH cycling/DDW group, and the nanoleakage was also less severe. Comparing with pH cycling/DDW group, the atomic percentages of Ca in the other two groups were both significantly higher, while those of Ag were statistically lower (P < 0.05).</p><p><b>CONCLUSION</b>Local application of CPP-ACP can promote the stability of resin-dentin bonding interface against pH cycling and prolong bonding degeneration.</p>

Targeting the substrate binding domain of polo-like kinase 1: advances in the study of PBD1 inhibitors / 药学学报

Polo-box domain 1 (PBD1) is a characteristic domain of polo-like kinase 1 (PLK1), which locates in C-terminal and can influence the catalytic activity and specific subcellular locations of PLK1. At present, most PLK1 inhibitors are developed to occupy the ATP pocket or its close sites. However, this kind of PLK1 inhibitors is difficult to pursue target selectivity and may encounter cross drug resistance with other kinase inhibitors due to the conserved sequence of ATP pocket. Recently, PBD1, with aberrant specificity in sequence and structure, has attracted enormous interests as the alternative target to the discovery of corresponding inhibitors for anti-tumor drugs. The structure and function of PBD1 as well as the advances of its inhibitors are reviewed in this paper.

Screen of phosphopeptide specific for acute leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To screen phosphopeptide specific for acute leukemia.</p><p><b>METHODS</b>Mononuclear cells from bone marrow were collected from 16 newly diagnosed acute lymphoblastic leukemia (ALL) and 20 acute myeloid leukemia (AML) patients. Peptides were extracted and purified, analyzed by immunoprecipitation and liquid chromatography coupled with tandem mass spectrometry (LC-MS).</p><p><b>RESULTS</b>(1) Non-receptor tyrosine kinase family members Fyn, Yes, Src widely expressed in acute leukemia; (2) Some phosphopeptides, including non-receptor tyrosine kinase family members Abl/iso1 and Abl, non-receptor Ser/Thr protein kinase family members Bcr, JNK2, JNK2 iso2, Adaptor/scaffold members Cas-L, Cbl, CrkL CENTD1 (Centaurin delta1) ZO2, transcriptor GFR-1 and phosphatase SHIP-2 were detected in Ph positive ALL, but not in other kinds of ALL. (3) Hck, Lyn and Fgr selectively expressed in AML (except AML-M(3)).</p><p><b>CONCLUSION</b>Some phosphopeptides were specific for ALL and AML, and may be useful for diagnosis and therapy of acute leukemia.</p>

Apoptosis induced by (di-isopropyloxyphoryl-Trp)2-Lys-OCH3 in K562 and HeLa cells.

According to the method used in our laboratory,our group synthesized (DIPP-Trp)2-Lys-OCH 3. It inhibited the proliferation of K562 and HeLa cells in a dose-and time-dependent manner with an IC 50 of 15.12 and 42.23 microM, respectively. (DIPP-Trp) 2-Lys-OCH3 induced a dose-dependent increase of the G2/M cell population in K562 cells, and S cell population in HeLa cells;the sub-G0 population increased dramatically in both cell lines as seen by PI staining experiments using a FACS Calibur Flow cytometer (BeckmanCoulter,USA). Phosphatidylserine could signi?cantly translocate to the surface of the membrane in (DIPP-Trp)2-Lys-OCH3-treated K562 and HeLa cells.The increase of an early apoptotic population was observed in a dose-dependent manner by both annexin-FITC and PI staining.It was concluded that (DIPP-Trp) 2-Lys-OCH3 not only induced cells to enter into apoptosis,but also affected the progress of the cell cycle.It may have arrested the K562 and HeLa cells in the G 2/M,S phases,respectively.The apoptotic pathway was pulsed at this point,resulting in the treated cells entering into programmed cell death.(DIPP- Trp)-Lys-OCH is a potential anticancer drug that intervenes in the signalling pathway.

A new fragmentation rearrangement of the N-terminal protected amino acids using ESI-MS/MS.

A novel fragmentation rearrangement reaction with a carboxyl oxygen negative charge migration was observed in the N-terminal protected amino acids including Fmoc-protected phosphoserine. phosphothroenine, and phosphotyrosine and their analogues using the electrospray ionization tandem mass spectrometry (ESI-MS/MS). The possible mechanism of a five-membered ring transition state was proposed and supported by the further experiments. It was found that the tendency of the rearrangement was determined by the blocking status of its C-terminal and the reaction was proved to be independent of the N-terminal and side-chain protecting groups of the amino acids.

Functional aspect of a phosphopeptide derived from calf thymus nuclei and DNA.

Phosphopeptides (PPs) isolated from highly purified calf thymus DNA (N-DNA) and extracted from calf thymus nuclei were fractionated, and the effect of one PP fraction on DNA replication has been examined. In the absence of inhibitors, the increasing PP concentration caused a linear decrease of 3H-thymidine uptake in L5178Y cells. If PP fraction was mildly hydrolysed with 1NHCl, the decrease in uptake was much steeper. The studies in which the inhibitors were used revealed that by the addition of the unhydrolysed PP fraction the inhibition of 3H-thymidine uptake by alpha-amanitin could be completely overcome, and that the inhibition by puromycin was reduced to 65-77% of the control. With puromycin, there was a gradual decrease of 3H-thymidine uptake with PP concentration above 3 mg/ml. The PPs gave an increase in incorporation of 3H-thymidine even after removal of alpha-amanitin and puromycin; thus, it is suggested that there is no direct interaction of either inhibitor with PP in the cell. Data on the utilization of 3H-cytidine for the synthesise of new DNA suggest that PP fraction might cause an acceleration of DNA replication.