Insights into the TOR-S6K Signaling Pathway in Maize (<i>Zea mays</i> L.). Pathway Activation by Effector–Receptor Interaction

The primordial TOR pathway, known to control growth and cell proliferation, has still not been fully described for plants. Nevertheless, in maize, an insulin-like growth factor (ZmIGF) peptide has been reported to stimulate this pathway. This research provides further insight into the TOR pathway in maize, using a biochemical approach in cultures of fast-growing (FG) and slow-growing (SG) calli, as a model system. Our results revealed that addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis and increased the growth rate through cell proliferation and increased the rate of ribosomal protein (RP) synthesis by the selective mobilization of RP mRNAs into polysomes. Furthermore, analysis of the phosphorylation status of the main TOR and S6K kinases from the TOR pathway revealed stimulation by ZmIGF or insulin, whereas rapamycin inhibited its activation. Remarkably, a putative maize insulin-like receptor was recognized by a human insulin receptor antibody, as demonstrated by immunoprecipitation from membrane protein extracts of maize callus. Furthermore, competition experiments between ZmIGF and insulin for the receptor site on maize protoplasts suggested structural recognition of the putative receptor by either effector. These data were confirmed by confocal immunolocalization within the cell membrane of callus cells. Taken together, these data indicate that cell growth and cell proliferation in maize depend on the activation of the TOR-S6K pathway through the interaction of an insulin-like growth factor and its receptor. This evidence suggests that higher plants as well as metazoans have conserved this biochemical pathway to regulate their growth, supporting the conclusion that it is a highly evolved conserved pathway

Investigation of mast cells in human gingiva following low-intensity laser irradiation

Objective: The aims of the present study were to investigate the effect of low-intensity laser irradiation on the total number of mast cells as well as the percentage of degranulation in human gingiva. Blood vessel dilation was also evaluated. Background Data: It has been proposed that low-intensity laser irradiation can ameliorate pain, swelling, and inflammation. In periodontal tissue, mast cells may influence either the destructive events or the defense mechanism against periodontal disease via secretion of cytokines and through cellular migration to improve the healing process. Mast cells play an important role in the inflammatory process. Methods: Twenty patients with gingival enlargement indicated for gingivectomy were selected. Gingival fragments were obtained from each patient and divided into three different groups before surgery. One fragment was removed without any irradiation. The two others were submitted to punctual irradiation with an energy density of 8 J/cm(2) at an output power of 50 mW at 36 Hz for 36 sec before gingivectomy. Nondegranulated and degranulated mast cells were counted in five areas of the gingival fragment connective tissue. Major and minor diameters of the blood vessels were also measured. Results: Both red and infrared radiation promoted a significant increase in mast cell degranulation compared to controls; however, no statistically significant differences (p > 0.05) were observed between the irradiated groups. No significant differences among the groups were observed regarding blood vessel size. Conclusion: The results suggests that red and infrared wavelengths promote mast cell degranulation in human gingival tissue, although no dilation of blood vessels was observed. The effects of premature degranulation of mast cells in human tissue and the laser radiation protocol applied in this study encourage further investigations to extend these results into clinical practice

La perspectiva de enfermos crónicos sobre la atención médica en Guadalajara, México. Un estudio cualitativo Perspectives of chronically ill patients concerning medical care in Guadalajara, Mexico. A qualitative study

Este trabajo reporta los hallazgos parciales de un estudio más amplio sobre la experiencia de vivir con enfermedades crónicas; el mismo se centra en la perspectiva de sujetos enfermos sobre los servicios de salud. Un estudio cualitativo fue realizado en un barrio popular de Guadalajara, con treinta sujetos con diabetes. La información se obtuvo mediante entrevistas semi y no estructuradas aplicadas en sus hogares. Los datos se obtuvieron durante un año, los mismos fueron analizados mediante análisis de contenido y conversacional. Tres valoraciones generales identificamos sobre la atención médica por parte de los participantes del estudio: algunos la consideran buena, para otros es ambivalente y para el resto es mala. Estas valoraciones se relacionan estrechamente con la trayectoria del padecimiento y los recursos materiales disponibles que posibilitan optar por distintos tipos de servicios. Tales perspectivas son cambiantes a lo largo del tiempo, incluyen los diversos servicios existentes y se construyen incorporando otros padecimientos crónicos. Quienes acuden al Seguro Social la definen en términos eminentemente negativos, a diferencia de aquellos con acceso a los servicios públicos de asistencia y a la medicina privada. Se discuten sus implicaciones en referencia a la reforma del sector salud.<br>This paper reports partial findings from a broader study on the experience of people with chronic diseases. The objective was to explore the perspectives of diabetic patients towards medical care. A qualitative study was conducted in a poor neighborhood of Guadalajara, Mexico. Thirty subjects with diabetes mellitus participated in the study. Data was gathered by open and semi-open interviews in the subjects' homes and over the course of one year. Data were analyzed using a combination of content and conversational analyzing techniques. Three perspectives predominated when participants evaluated medical care: some define it as good, some as ambivalent, and the rest as bad. These perspectives were closely linked to their disease experience and available medical options according to their material resources. These perspectives change with time, are specific to each available service and type of medical care, and are constructed in terms of all the subjects' present chronic illnesses. Those treated through the social security system evaluate the care in negative terms, with the opposite occurring with those treated in public health care centers and private facilities. Implications regarding health care reform are discussed