Conócete a tí mismo : tratado popular de fisiología humana ó sea explicación al alcance de todas las inteligencias de como...

UANL

Tratado elemental de fisiología humana /

Contiene: T. I - T. II.

Strong iron demand during hypoxia-induced erythropoiesis is associated with down-regulation of iron-related proteins and myoglobin in human skeletal muscle

[EN] Iron is essential for oxygen transport because it is incorporated in the heme of the oxygen-binding proteins hemoglobin and myoglobin. An interaction between iron homeostasis and oxygen regulation is further suggested during hypoxia, in which hemoglobin and myoglobin syntheses have been reported to increase. This study gives new insights into the changes in iron content and iron-oxygen interactions during enhanced erythropoiesis by simultaneously analyzing blood and muscle samples in humans exposed to 7 to 9 days of high altitude hypoxia (HA). HA up-regulates iron acquisition by erythroid cells, mobilizes body iron, and increases hemoglobin concentration. However, contrary to our hypothesis that muscle iron proteins and myoglobin would also be up-regulated during HA, this study shows that HA lowers myoglobin expression by 35% and down-regulates iron-related proteins in skeletal muscle, as evidenced by decreases in L-ferritin (43%), transferrin receptor (TfR; 50%), and total iron content (37%). This parallel decrease in L-ferritin and TfR in HA occurs independently of increased hypoxia-inducible factor 1 (HIF-1) mRNA levels and unchanged binding activity of iron regulatory proteins, but concurrently with increased ferroportin mRNA levels, suggesting enhanced iron export. Thus, in HA, the elevated iron requirement associated with enhanced erythropoiesis presumably elicits iron mobilization and myoglobin down-modulation, suggesting an altered muscle oxygen homeostasis.

Gender dimorphism in skeletal muscle leptin receptors, serum leptin and insulin sensitivity

[EN] To determine if there is a gender dimorphism in the expression of leptin receptors (OB-R170, OB-R128 and OB-R98) and the protein suppressor of cytokine signaling 3 (SOCS3) in human skeletal muscle, the protein expression of OB-R, perilipin A, SOCS3 and alpha-tubulin was assessed by Western blot in muscle biopsies obtained from the m. vastus lateralis in thirty-four men (age = 27.1+/-6.8 yr) and thirty-three women (age = 26.7+/-6.7 yr). Basal serum insulin concentration and HOMA were similar in both genders. Serum leptin concentration was 3.4 times higher in women compared to men (P<0.05) and this difference remained significant after accounting for the differences in percentage of body fat or soluble leptin receptor. OB-R protein was 41% (OB-R170, P<0.05) and 163% (OB-R128, P<0.05) greater in women than men. There was no relationship between OB-R expression and the serum concentrations of leptin or 17beta-estradiol. In men, muscle OB-R128 protein was inversely related to serum free testosterone. In women, OB-R98 and OB-R128 were inversely related to total serum testosterone concentration, and OB-R128 to serum free testosterone concentration. SOCS3 protein expression was similar in men and women and was not related to OB-R. In women, there was an inverse relationship between the logarithm of free testosterone and SCOS3 protein content in skeletal muscle (r = -0.46, P<0.05). In summary, there is a gender dimorphism in skeletal muscle leptin receptors expression, which can be partly explained by the influence of testosterone. SOCS3 expression in skeletal muscle is not up-regulated in women, despite very high serum leptin concentrations compared to men. The circulating form of the leptin receptor can not be used as a surrogate measure of the amount of leptin receptors expressed in skeletal muscles.

Exercise and bone mass in adults

[EN] There is a substantial body of evidence indicating that exercise prior to the pubertal growth spurt stimulates bone growth and skeletal muscle hypertrophy to a greater degree than observed during growth in non-physically active children. Bone mass can be increased by some exercise programmes in adults and the elderly, and attenuate the losses in bone mass associated with aging. This review provides an overview of cross-sectional and longitudinal studies performed to date involving training and bone measurements. Cross-sectional studies show in general that exercise modalities requiring high forces and/or generating high impacts have the greatest osteogenic potential. Several training methods have been used to improve bone mineral density (BMD) and content in prospective studies. Not all exercise modalities have shown positive effects on bone mass. For example, unloaded exercise such as swimming has no impact on bone mass, while walking or running has limited positive effects.

Androgen receptor gene polymorphisms lean mass and performance in young men

[EN] The exon-1 of the androgen receptor (AR) gene contains two repeat length polymorphisms which modify either the amount of AR protein inside the cell (GGN(n), polyglycine) or its transcriptional activity (CAG(n), polyglutamine). Shorter CAG and/or GGN repeats provide stronger androgen signalling and vice versa. To test the hypothesis that CAG and GGN repeat AR polymorphisms affect muscle mass and various variables of muscular strength phenotype traits, the length of CAG and GGN repeats was determined by PCR and fragment analysis and confirmed by DNA sequencing of selected samples in 282 men (28.6 +/- 7.6 years). Individuals were grouped as CAG short (CAG(S)) if harbouring repeat lengths of 21. GGN was considered short (GGN(S)) or long (GGN(L)) if GGN 23, respectively. No significant differences in lean body mass or fitness were observed between the CAG(S) and CAG(L) groups, or between GGN(S) and GGN(L) groups, but a trend for a correlation was found for the GGN repeat and lean mass of the extremities (r=-0.11, p=0.06). In summary, the lengths of CAG and GGN repeat of the AR gene do not appear to influence lean mass or fitness in young men.

Efecto de la presión hiperbárica y diferentes presiones parciales de gases sobre la modulación vegetativa de la respuesta cardiaca : aplicación de métodos lineales y no lineales en el análisis de VFC

Programa de doctorado: Actividad Física, Salud y Rendimiento Deportivo

Influencia del polimorfismo del receptor de andrógenos en la masa grasa corporal y la respuesta lipolítica al ejercicio

Programa de doctorado: Actividad Física, Salud y Rendimiento Deportivo Premio Extraordinario de Doctorado en la rama de Ciencias Sociales y Jurídicas, 2011-2012

Regulación alfa1-adrenérgica de la corriente IKr cardiaca

149 p. : il., graf.

Identificación y caracterización de centros de unión para purinas de membrana plasmática de células aisladas de glándulas gástricas

149 p. : il.

Impacto del ejercicio físico sobre la calidad de vida en las personas que padecen cardiopatía isquémica

184 p.

“Pildorón”: ¿El fármaco del futuro?

Duración (en horas): De 41 a 50 horas Destinatario: Estudiante y Docente

Pathophysiology of feline hyperadrenocorticism clinical. Case presentation

Hyperadrenocorticism is a rare endocrine disease in the cat; it is characterized by elevated blood cortisol level that generates numerous clinical signs including hyperglycemia, polyuria, polydipsia, polyphagia and skin diseases. The average age of onset is around 10 years. This disease usually occurs link with other endocrine disorders such as diabetes mellitus.The disease can be produced by functional alteration of the pituitary gland or the adrenal. A case report, with differential diagnosis and review of the literature, is presented.