Interplay of Oxidants and Antioxidants in Mammalian Embryo Culture System.

One principal purpose of assisted reproductive technology (ART) is to produce viable and good quality embryos. However, a variety of environmental factors may induce epigenetic changes in the embryo. Moreover, laboratory conditions including the culture media may also affect embryo development. Therefore, media change is an important factor in maintaining proper oxidant/antioxidant balance during embryo culture. Alterations in the oxidant/antioxidant balance are related to various cellular responses such as an increase in the level of reactive oxygen species (ROS) and consequent lipid peroxidation (LPO), DNA damage, and apoptosis. The current study focuses on the role of external factors on embryo culture and the ability of antioxidants to enhance in vitro fertilization (IVF) outcomes. Indeed, an optimization of media culture by the addition of enzymatic and nonenzymatic antioxidants in animal models and human embryos in ART has been updated in this study, with an emphasis on comparing the available results and their possible reasons.

Somatotropinomas, but not nonfunctioning pituitary adenomas, maintain a functional apoptotic RET/Pit1/ARF/p53 pathway that is blocked by excess GDNF.

Acromegaly is caused by somatotroph cell adenomas (somatotropinomas [ACROs]), which secrete GH. Human and rodent somatotroph cells express the RET receptor. In rodents, when normal somatotrophs are deprived of the RET ligand, GDNF (Glial Cell Derived Neurotrophic Factor), RET is processed intracellularly to induce overexpression of Pit1 [Transcription factor (gene : POUF1) essential for transcription of Pituitary hormones GH, PRL and TSHb], which in turn leads to p19Arf/p53-dependent apoptosis. Our purpose was to ascertain whether human ACROs maintain the RET/Pit1/p14ARF/p53/apoptosis pathway, relative to nonfunctioning pituitary adenomas (NFPAs). Apoptosis in the absence and presence of GDNF was studied in primary cultures of 8 ACROs and 3 NFPAs. Parallel protein extracts were analyzed for expression of RET, Pit1, p19Arf, p53, and phospho-Akt. When GDNF deprived, ACRO cells, but not NFPAs, presented marked level of apoptosis that was prevented in the presence of GDNF. Apoptosis was accompanied by RET processing, Pit1 accumulation, and p14ARF and p53 induction. GDNF prevented all these effects via activation of phospho-AKT. Overexpression of human Pit1 (hPit1) directly induced p19Arf/p53 and apoptosis in a pituitary cell line. Using in silico studies, 2 CCAAT/enhancer binding protein alpha (cEBPα) consensus-binding sites were found to be 100% conserved in mouse, rat, and hPit1 promoters. Deletion of 1 cEBPα site prevented the RET-induced increase in hPit1 promoter expression. TaqMan qRT-PCR (real time RT-PCR) for RET, Pit1, Arf, TP53, GDNF, steroidogenic factor 1, and GH was performed in RNA from whole ACRO and NFPA tumors. ACRO but not NFPA adenomas express RET and Pit1. GDNF expression in the tumors was positively correlated with RET and negatively correlated with p53. In conclusion, ACROs maintain an active RET/Pit1/p14Arf/p53/apoptosis pathway that is inhibited by GDNF. Disruption of GDNF's survival function might constitute a new therapeutic route in acromegaly.

Síndrome de Cushing y otros tumores hipofisarios / No disponible

No disponible

Influence of reduction in the elution times on HPLC glycohaemoglobin results.

OBJECTIVES: To compare HPLC methods with short and long elution times for HbA1c measurement in blood. METHODS: Comparison between G7-Tosoh (1.2 min); Bio-Rad-Variant-II-Turbo (1.3 min) and Arkray-HA-8160 (2.9 min). RESULTS: Passing-Bablok regression equations were: Y=0.17+0.96X; Y=-0.39+1.01X; Y=-0.40+1.0X and the means of the differences using Bland-Altman Plot were 0.02; -0.34; 0.32 for HA-8160/G7-Tosoh, HA-8160/Variant-II-Turbo and G7-Tosoh/Variant-II-Turbo, respectively. CONCLUSIONS: Faster elution methods had no problems on reproducibility of results obtained by slower elution methods.

Identification and characterization of two novel truncated but functional isoforms of the somatostatin receptor subtype 5 differentially present in pituitary tumors.

CONTEXT: Somatostatin and its related peptide cortistatin exert multiple actions on normal and tumoral tissue targets through a family of receptors termed somatostatin receptor (sst)1-5. Despite the considerable advances in the knowledge on these receptors and their (patho)physiological roles, there is still evidence that additional receptors for these peptides should exist to fully explain their actions. OBJECTIVE: The growing number of spliced variants found in similar receptor families, often present in tumors, and results from our group obtained on sst5 from other species (pig) led us to explore the existence of new human sst5 isoforms. DESIGN AND RESULTS: A rapid amplification of cDNA ends PCR approach on samples from a human pituitary tumor and a cell line enabled identification of two novel alternatively spliced sst5 receptor variants. The sequences obtained encode putative proteins that correspond to truncated isoforms of five and four transmembrane domains (TMDs), accordingly named sst5TMD5 and sst5TMD4, respectively. Both novel receptors show a differential expression pattern in normal tissues and are also present in pituitary tumors of diverse etiology including nonfunctioning adenomas, corticotropinomas, somatotropinomas, and a prolactinoma. In contrast to the predominant plasma membrane localization of full-length sst5, both sst5TMD5 and sst5TMD4 show a preferentially intracellular localization. Despite their truncated nature, both receptors are functional, as shown by their ability to mediate selective, ligand-induced rises in free cytosolic calcium concentration. Specifically, whereas sst5TMD5 is selectivity activated by somatostatin compared with cortistatin, cells transfected with sst5TMD4 almost exclusively respond to cortistatin and not to somatostatin. CONCLUSIONS: Our results demonstrate the existence of two previously unidentified sst5 spliced variants with distinct distribution in normal tissues and pituitary tumors, unique ligand-selective signaling properties, and subcellular distribution, which could contribute to somatostatin and cortistatin signaling in normal and tumoral cells.

Effect of obesity and morbid obesity on the growth hormone (GH) secretion elicited by the combined GHRH + GHRP-6 test.

OBJECTIVE: Obesity is characterized by low basal levels of growth hormone (GH) and impeded GH release. However, the main problem arises in the diagnosis of GH deficiency in adults, as all accepted cut-offs in the diagnostic tests of GH reserve are no longer valid in obese subjects. In this work, the role of obesity in the GH response elicited by the GHRH + GHRP-6 test was assessed in a large population of obese and nonobese subjects. PATIENTS: GHRH + GHRP-6-induced GH peaks were evaluated in 542 subjects. One hundred and five were healthy obese, 50 were morbid obese, and 261 were nonobese (both normal weight and overweight). One hundred and seventy-six GH-deficient patients (obese and nonobese) were also studied. RESULTS: A regression analysis of the 366 subjects with normal pituitary function indicated that adiposity had a negative effect on the elicited GH peak (r = -0.503, P < 0.0001). A receiver operating characteristic (ROC) curve analysis showed that in subjects with a BMI < or =35, the currently accepted cut-offs of the GHRH + GHRP-6 test (GH peaks > or =20 microg/l: normal secretion; GH peaks < or =10 microg/l: GH deficiency), were fully operative. However, in subjects with a BMI > 35, normality was indicated by GH peaks > or =15 microg/l and GH deficiency by peaks < or =5 microg/l (1 microg/l = 2.6 mU/l). CONCLUSIONS: This study confirms: (a) that the combined provocative test is adequate to separate normal and GH-deficient subjects; (b) the negative effect of obesity on GH secretion; (c) that obesity accounts for 25% of the reduction of GH release; and (d) that present cut-off values are applicable to normal weight, overweight and grade I obesity subjects, whereas in obese subjects with a BMI exceeding 35, all the normative limits of the GHRH-GHRP +6 test must be reduced by 5 microg/l.

Traumatic brain injury as a relevant cause of growth hormone deficiency in adults: A KIMS-based study.

OBJECTIVES: To characterize further the clinical manifestations and the efficacy of growth hormone (GH) replacement therapy in patients with adult-onset growth hormone deficiency (GHD) reported in the KIMS (Pfizer's international metabolic database) as caused by traumatic brain injury (TBI) and to compare them with nonirradiated patients whose GHD was due to a nonfunctioning pituitary adenoma (NFPA). DESIGN: Observational study. SETTING: Subjects selected from the KIMS database. PARTICIPANTS: Fifty-one patients with GHD resulting from TBI and 688 patients with GHD resulting from NFPA. Both groups were selected from the KIMS and had adult-onset GHD with GH replacement therapy only after KIMS entry and before and after KIMS entry. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Age, body mass index, age at disease onset, age at disease diagnosis, age at KIMS entry, final height, GH peak at testing, GH replacement dose, routine biochemical analysis, clinical manifestations of disease, and quality of life measurements. RESULTS: Patients with TBI were significantly younger at study entry and were younger both at pituitary disease onset and at GHD diagnosis, but they showed a significant delay in treatment. When comparing patients not treated with GH before entering in the KIMS, patients with TBI were significantly shorter (167.2+/-1.7 cm) than those with NFPA (171.6+/-0.4 cm) in final height. TBI patients had lower GH reserves than NFPA patients, and although the latter group experienced more positive changes, both groups benefited from GH replacement therapy. CONCLUSIONS: Patients with GHD due to TBI showed a significant reduction in height and a reduction in pituitary GH reserve and were diagnosed and treated with inappropriate delay.

Growth hormone (GH) peaks versus areas under the curve in the diagnosis of adult GH deficiency: analysis of the variables provided by the GHRH + GHRP-6 test.

BACKGROUND: The diagnosis of growth hormone deficiency (GHD) relies on provocative tests of GH reserve. The aim in these tests is to obtain an objective, biochemical-based, measure of gland function, but clinicians and researchers rely on the GH peak, as a surrogate of the 24-hour pituitary secretion. However, on a mathematical basis the area under the secretory curve (AUC) should be more valid for this evaluation. OBJECTIVES: To validate which variable provided by a provocative test of GH secretion is mathematically more robust for supporting the clinical diagnosis. Adult normal subjects and GHD patients were challenged with the combined stimulus GHRH + GHRP-6. The diagnostic efficacy of the GH peak, and the AUC were compared by the receiver operating characteristic (ROC) curve methodology. PATIENTS AND METHODS: 146 patients with GH deficiency due to organic pituitary disease and 184 healthy subjects were administered GHRH 1 microg/Kg iv, plus GHRP-6 1 microg/Kg iv, and GH was determined. Four variables were studied: (a) the GH peak; (b) the "standard" AUC, (c) the "stimulated" AUC and (d) the basal value, used as internal control. RESULTS: Under ROC curve analysis, the basal variable was devoid of diagnostic capability, while the other variables performed strikingly well, the ROC curve area for the GH peak was 0.9997; and for the AUC 0.9993, with no statistical differences. CONCLUSIONS: The variables provided by measuring the GH peak and the area under the curve were similarly effective for diagnosis, although on clinical grounds, the peak was more convenient as needed no calculation. If results for other test were similar the time-honored method of measuring the GH peak could be considered mathematically validated.

Disminución de la actividad de la 11- ß-hidroxiesteroide deshidrogenasa en pacientes con síndrome de Cushing / Decreased activity of 11-ß-hydroxysteroid dehydrogenase in patients with Cushing's syndrome

Fundamento: Análisis de la actividad de la 11-ß-hidroxiesteroide deshidrogenasa en el síndrome de Cushing. Pacientes y método: Determinación de la eliminación en orina de 24 h de cortisol, cortisona y sus tetrahidroderivados en 15 pacientes con síndrome de Cushing y 24 controles sanos. Resultados: Existía una relación lineal significativa entre cortisol y cortisona (r = 0,70; p < 0,0001) y entre sus tetrahidroderivados (r = 0,75; p < 0,0001) en los controles, pero no en los pacientes. Conclusiones: Los pacientes con síndrome de Cushing presentan un déficit de la actividad de la 11-ß-hidroxiesteroide deshidrogenasa (AU)

El papel del vector Aedes aegypti en la epidemiología del dengue en México / The role of Aedes aegypti in the epidemiology of dengue fever in Mexico

Se discute el papel del Aedes aegypti (Lineo) en la epidemiología del dengue en México usando como referencia el modelo de la capacidad vectorial. Se presentan comentarios sobre las ventajas y desventajas de cada uno de los componentes de este modelo al momento de su determinación en campo. Se enfatiza cómo la suma de errores metodológicos y de muestreo, afecta finalmente el resultado de la capacidad vectorial. Se subraya la necesidad de incrementar el conocimiento en la biología del Aedes aegypti, como una respuesta a las necesidades de la epidemiología en su tarea de predecir y explicar brotes de dengue, y se comenta sobre variables potenciales de importancia epidemiológica de origen entomológico que del modelo cuantitativo no considera. Finalmente, se menciona la introducción del Aedes albopictus (Skuse) en México y cómo esto viene a complicar más la comprensión de la transmisión del dengue

The role of Aedes aegypti (Lineo) in the epidemiology of dengue fever in Mexico is herein discussed based on the vectorial capacity model. Comments on the advantages and disadvantages of each model component at the time of field determinations are also presented. Emphasis is made on the impact of sampling and method bias on the results of vectorial capacity studies. The paper also addresses the need to increase vector biology knowledge as an input for epidemiological work to explain and predict dengue fever outbreaks. Comments on potential entomological variables not considered by the quantitative model are included. Finally, we elaborate on the introduction of Aedes albopictus (Skuse) in Mexico as a new risk factor and on its implications for the understanding of dengue fever transmission in Mexico.