Evaluation of protein undernourishment on the condylar process of the Wistar rat mandible correlation with insulin receptor expression

The mandible condylar process cartilage (CP) of Wistar rats is a secondary cartilage and acts as a mandibular growth site. This phenomenon depends on adequate proteins intake and hormone actions, including insulin. Objectives The present study evaluated the morphological aspects and the expression of the insulin receptor (IR) in the cartilage of the condylar process (CP) of rats subjected to protein undernourishment. Material and Methods The nourished group received a 20% casein diet, while the undernourished group (U) received a 5% casein diet. The re-nourished groups, R and RR, were used to assess the effects of re-nutrition during puberty and adulthood, respectively. CPs were processed and stained with picro-sirius red, safranin-O and azocarmine. Scanning electron microscopy and immunohistochemistry were also performed. Results The area of the CP cartilage and the number of cells in the chondroblastic layer decreased in the U group, as did the thickness of the CP layer in the joint and hypertrophic layer. Renourishment during the pubertal stage, but not during the adult phase, restored these parameters. The cell number was restored when re-nutrition occurred in the pubertal stage, but not in the adult phase. The extracellular matrix also decreased in the U group, but was restored by re-nutrition during the pubertal stage and further increased in the adult phase. IR expression was observed in all CPs, being higher in the chondroblastic and hypertrophic cartilage layers. The lowest expression was found in the U and RR groups. Conclusions Protein malnutrition altered the cellularity, the area, and the fibrous cartilage complex, as well as the expression of the IRs. .

Meta-tyrosine: A powerful anti-metastatic factor with undetectable toxic-side effects

Concomitant tumor resistance (CR) is a phenomenon in which a tumor-bearing host is resistant to the growth of secondary tumor implants and metastasis. While former studies have indicated that T-cell dependent processes mediate CR in hosts bearing immunogenic small tumors, the most universal manifestation of CR induced by immunogenic and non-immunogenic large tumors had been associated with an antitumor serum factor that remained an enigma for many years. In a recent paper, we identified that elusive factor(s) as an equi-molar mixture of meta-tyrosine and ortho-tyrosine, two isomers of tyrosine that are not present in normal proteins and that proved to be responsible for 90% and 10%, respectively, of the total serum anti-tumor activity. In this work, we have extended our previous findings demonstrating that a periodic intravenous administration of meta-tyrosine induced a dramatic reduction of lung and hepatic metastases generated in mice bearing two different metastatic murine tumors and decreased the rate of death from 100% up to 25% in tumor-excised mice that already exhibited established metastases at the time of surgery. These anti-metastatic effects were achieved even at very low concentrations and without displaying any detectable toxic-side effects, suggesting that the use of meta-tyrosine may help to develop new and less harmful means of managing malignant diseases, especially those aimed to control the growth of metastases that is the most serious problem in cancer pathology.

La resistencia concomitante antitumoral (RC) es el fenómeno según el cual un individuo portador de tumor inhibe el crecimiento de implantes tumorales secundarios y metástasis. Si bien desde hace tiempo se sabe que la RC inducida por tumores inmunogénicos de pequeño tamaño es generada por mecanismos inmunológicos dependientes de células T, por otro lado, la manifestación más universal de la RC, generada tanto por tumores inmunogénicos como no-inmunogénicos de gran tamaño, había sido asociada con un (unos) factor sérico antitumoral cuya naturaleza permaneció elusiva por años. En un trabajo reciente, nuestro grupo de trabajo identificó este factor como la mezcla equi-molar de meta-tirosina y orto-tirosina, dos isómeros de tirosina que no están presentes en proteínas normales y que demostraron ser responsables del 90% y 10%, respectivamente, de la actividad antitumoral total del suero. En este trabajo, continuamos nuestras investigaciones demostrando que la administración periódica de meta-tirosina reducía drásticamente el número de metástasis pulmonares y hepáticas en ratones portadores de dos tumores murinos altamente metastásicos y disminuía dramáticamente la mortandad (de 100% a 25%) de ratones con metástasis ya establecidas al momento de la extirpación quirúrgica del tumor. Estos efectos anti-metastásicos se lograron aun con muy bajas concentraciones de meta-tirosina y sin efectos tóxicos perceptibles, lo que sugiere que su uso puede ayudar a diseñar nuevas y menos nocivas estrategias para el tratamiento del cáncer, especialmente aquellas destinadas a controlar el crecimiento metastásico, que es el problema más grave en la enfermedad oncológica.

Consumption and expenditure on food prepared away from home among Mexican adults in 2006 / Consumo y gasto en alimentos preparados fuera de casa en adultos mexicanos en 2006

Objective. To describe food expenditure and consumption of foods prepared away from home among Mexican adults. Materials and methods. Data were from 45 241 adult participants in the National Health and Nutrition Survey 2006, a nationally-representative, cross-sectional survey of Mexican households. Descriptive statistics and multivariable linear and logistic regression were used to assess the relationship between location of residence, educational attainment, socioeconomic status and the following: 1) expenditure on all food and at restaurants, and 2) frequency of consumption of comida corrida or restaurant food and street food. Results. Food expenditure and consumption of food prepared away from home were positively associated with socioeconomic status, educational attainment, and urban vs. rural residence (p<0.001 for all relationships in bivariate analyses). Conclusions. Consumption of food prepared outside home may be an important part of the diet among urban Mexican adults and those with high socioeconomic status and educational attainment.

Objetivo. Describir los gastos en alimentos y el consumo de alimentos preparados fuera de casa en población mexicana. Material y métodos. Los datos fueron de 45 241 adultos mexicanos en la Encuesta Nacional de Salud y Nutrición de 2006, representativa al nivel nacional. Se utilizaron estadísticas descriptivas y regresión linear y logística para estimar la relación entre el lugar de residencia, el nivel educativo y el nivel socioeconómico, con el gasto en todos los alimentos y en restaurantes, y con la frecuencia de consumo de comida corrida, en restaurantes y de la calle. Resultados. El gasto en alimentos y el consumo de alimentos preparados se asociaron positivamente con el nivel socioeconómico, el nivel educativo y la residencia rural (p<0,001 para todas las relaciones). Conclusiones. El consumo de alimentos preparados puede ser una parte importante de la dieta de los adultos urbanos y de aquéllos con altos niveles socioeconómicos y educativos.

A novel assay method for calcium calmodulin dependent phosphatase from bovine brain extract.

Calcium calmodulin dependent protein ser/thr phosphatase, also referred to as protein phosphatase 2B (PP2B), is rich in neural tissue, and plays an important role in the overall function of the nervous system. Routinely phosphatase assay employs, para-Nitrophenlylphosphate (p-NPP), as a substrate, is also extended to assay PP2B. However, in the present study, the differential spectral characterstic property of tyrosine and phopshotyrosine has been exploited to employ the latter as a candidate substrate for the PP2B assay. The specific activity of PP2B using phosphortyrosine in bovine Bos Taurus indicus brain extract (Bos Taurus indicus), was measured in presence of different metal ions like Ca2+, Mn2+ and Mg2+. Further modulators like dithiothreitol (DTT), calmodulin (CaM) and metal chelators such as EGTA and EDTA were applied to confirm the role of divalent cations and to determine calcium calmodulin dependent phoshphatase activity. PP2B activity was higher with phosphotyrosine in presence of Ca2+ than with p-NPP. Further experiments, involving calmodulin as a modulator, confirmed phosphotyrosine as a better substrate over p-NPP. Calmodulin further enhanced the effect of phosphotyrosine as a potential substrate confirming calcium calmodulin dependent phosphatase activity. Phosphotyrosine is proposed as a better substrate in assaying calcium dependent phosphatase activity when compared to para-nitrophenylphosphate.

The Role of Tyrosine 207 in the Reaction Catalyzed by Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase

The functional signifcance of tyrosine 207 of Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase was explored by examining the kinetic properties of the Tyr207Leu mutant. The variant enzyme retained the structural characteristics of the wild-type protein as indicated by circular dichroism, intrinsic fuorescence spectroscopy, and gel-exclusion chromatography. Kinetic analyses of the mutated variant showed a 15-fold increase in Km CO2, a 32fold decrease in Vmax, and a 6-fold decrease in Km for phosphoenolpyruvate. These results suggest that the hydroxyl group of Tyr 207 may polarize CO2 and oxaloacetate, thus facilitating the carboxylation/decarboxylation steps.

Proteins implicated in sperm capacitation.

Spermatozoa after being deposited in the female reproductive tract spend a considerable time in this foreign environment prior to fertilization of the oocyte. Chang and Austin independently observed1,2 that this time spent by the spermatozoa in the female tract is not consequential but a necessary event in the life cycle of the male gamete, and Austin2 first called this maturation period of spermatozoa as 'Capacitation'. Ever since, attempts have been made to understand and unravel the molecular mechanism of capacitation. Based on the results obtained so far, it is clear that capacitation is guided by novel signal transduction pathways influencing varied aspects of spermatozoa. Capacitation could be, thus, defined as the cumulative molecular, cellular and physiological changes that occur in spermatozoa in the female reproductive tract to achieve the final competence to fertilize the oocyte. This review is structured so as to first understand the key features of capacitation and then to survey the players which bring about these changes during capacitation.

Chemical modifications and dissociation characteristics of tyrosine and tryptophan residues in alpha-crystallin.

A quantitative estimation of surface accessibility of aromatic residues in alpha-crystallin from goat lens has been accomplished by chemical modifications using different specific reagents having varying sizes. Results of modification of tyrosine residues with N-acetylimidazole and tetranitromethane when combined with those of ionization studies carried out with hydroxyl ions having the smallest size reveal different classes of tyrosine residues in the native protein: 78 +/- 2 residues have been found to be easily available for modification; among the rest, 94 +/- 2 residues appear to be comparatively less exposed to the reagents while 28 +/- 2 residues are found to be completely unavailable for modification in the native protein and are modified only when the protein is denatured. Modification of tryptophan residues with H2O2 also indicates different classes of these residues available for oxidation at different concentrations of the oxidant. 34 +/- 2 residues of tryptophan are found to be easily oxidized at a lower concentration of H2O2 during the first phase of the reaction. The remaining tryptophan residues appear to be less exposed to the reagent. This is also corroborated from the studies of reactivities of these residues towards another specific but bulkier reagent, 2-hydroxy-5-nitrobenzyl bromide. These surface exposed aromatic residues in alpha-crystallin may be considered to be vulnerable to in vivo oxidative modifications forming insoluble aggregates which may finally contribute to the formation of cataract.

Photochemistry and photobiology of actinic erythema: defensive and reparative cutaneous mechanisms

Sunlight is part of our everyday life and most people accept it as beneficial to our health. With the advance of our knowledge in cutaneous photochemistry, photobiology and photomedicine over the past four decades, the terrestrial solar radiation has become a concern of dermatologists and is considered to be a major damaging environmental factor for our skin. Most photobiological effects (e.g., sunburn, suntanning, local and systemic immunosuppression, photoaging or dermatoheliosis, skin cancer and precancer, etc.) are attributed to ultraviolet radiation (UVR) and more particularly to UVB radiation (290-320 nm). UVA radiation (320-400 nm) also plays an important role in the induction of erythema by the photosensitized generation of reactive oxygen species (singlet oxygen ((1)O2))superoxide (O2-) and hydroxyl radicals ((OH) that damage DNA and cellular membranes, and promote carcinogenesis and the changes associated with photoaging. Therefore, research efforts have been directed at a better photochemical and photobiological understanding of the so-called sunburn reaction, actinic or solar erythema. To survive the insults of actinic damage, the skin appears to have different intrinsic defensive mechanisms, among which antioxidants (enzymatic and non-enzymatic systems) play a pivotal role. In this paper, we will review the basic aspects of the action of UVR on the skin: a) photochemical reactions resulting from photon absorption by endogenous chromophores; b) the lipid peroxidation phenomenon, and c) intrinsic defensive cutaneous mechanisms (antioxidant systems). The last section will cover the inflammatory response including mediator release after cutaneous UVR exposure and adhesion molecule expression.