Publications by authors named "Edith Sanchez"

Efficient pathogen diagnostics and genotyping methods enable effective disease management and breeding, improve crop productivity and ensure food security. However, current germplasm selection and pathogen detection techniques are laborious, time-consuming, expensive and not easy to mass-scale application in the field. Here, we optimized a field-deployable lateral flow assay, Bio-SCAN, as a highly sensitive tool to precisely identify elite germplasm and detect mutations, transgenes and phytopathogens in <1 h, starting from sample isolation to result output using lateral flow strips.

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Simple, rapid, specific, and sensitive point-of-care detection methods are needed to contain the spread of SARS-CoV-2. CRISPR/Cas9-based lateral flow assays are emerging as a powerful alternative for COVID-19 diagnostics. Here, we developed Bio-SCAN (biotin-coupled specific CRISPR-based assay for nucleic acid detection) as an accurate pathogen detection platform that requires no sophisticated equipment or technical expertise.

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Over the last 26 years, the Mexican government has developed a number of activities and discourses around what has been called "intercultural health," directed especially at indigenous peoples in Mexico (some 62, according to linguistic criteria). In this way, the government has built health care institutions (rural centers, clinics, and hospitals) in states like Puebla, Nayarit, Oaxaca, Chiapas, Queretaro, and Jalisco, proposing the implementation of cultural pertinence indicators (which are minimal and inadequate). Nevertheless, the health conditions among indigenous populations and the quality of health care provided by public institutions continue to be precarious in terms of human and material resources (health personnel, drugs, etc.

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The activity of the hypothalamus-pituitary-thyroid (HPT) axis is essential for energy homeostasis and is differentially modulated by physical and by psychological stress. Contradictory effects of stressful behavioral paradigms on TSH or thyroid hormone release are due to type, length and controllability of the stressor. We hypothesized that an additional determinant of the activity of the HPT axis is the energy demand due to physical activity.

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Article Synopsis
  • * In experiments with male Wistar rats subjected to different stress tests, TRH and proCRH mRNA levels were analyzed post-stress, showing that restraint increased proCRH mRNA but not proTRH, while corticosterone levels heightened across all stress paradigms.
  • * The study revealed that increased TRH expression in the amygdala correlates with reduced anxiety, particularly during dark phases, indicating that TRH may play a role in fear processing and anxiety regulation under varying stress conditions and circadian rhythms.
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Suppression of TSH release from the hypothyroid thyrotrophs is one of the most rapid effects of 3,3',5'-triiodothyronine (T(3)) or thyroxine (T(4)). It is initiated within an hour, precedes the decrease in TSHβ mRNA inhibition and is blocked by inhibitors of mRNA or protein synthesis. TSH elevation in primary hypothyroidism requires both the loss of feedback inhibition by thyroid hormone in the thyrotrophs and the positive effects of TRH.

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Hypophysiotropic thyrotropin-releasing hormone (TRH) neurons, the central regulators of the hypothalamic-pituitary-thyroid axis, are located in the hypothalamic paraventricular nucleus (PVN) in a partly overlapping distribution with non-hypophysiotropic TRH neurons. The distribution of hypophysiotropic TRH neurons in the rat PVN is well understood, but the localization of these neurons is unknown in mice. To determine the distribution and phenotype of hypophysiotropic TRH neurons in mice, double- and triple-labeling experiments were performed on sections of intact mice, and mice treated intravenously and intraperitoneally with the retrograde tracer Fluoro-Gold.

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To determine whether signaling through TNF and/or nuclear factor-kappaB contributes to bacterial lipopolysaccharide (LPS)-induced activation of type 2 iodothyronine deiodinase (D2) in tanycytes lining the floor and infralateral walls of the third ventricle, the effect of a TNF antagonist on D2 gene expression and LPS-induced Ikappa-Balpha expression in tanycytes were studied. Animals treated with soluble, rat, polyethylene glycol-conjugated TNF receptor type 1 (4 mg/kg body weight) before a single ip injection of LPS showed a significant reduction in circulating IL-6 levels but no effect on LPS-induced D2 mRNA in the majority of tanycytes with the exception of a subpopulation of alpha tanycytes in the wall of the third ventricle. LPS induced a rapid increase in Ikappa-Balpha mRNA in the pars tuberalis and a delayed response in alpha tanycytes but absent in all other tanycyte subsets.

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Hypothyroidism in humans is characterized by severe neurological consequences that are often irreversible, highlighting the critical role of thyroid hormone (TH) in the brain. Despite this, not much is known about the signaling pathways that control TH action in the brain. What is known is that the prohormone thyroxine (T4) is converted to the active hormone triiodothyronine (T3) by type 2 deiodinase (D2) and that this occurs in astrocytes, while TH receptors and type 3 deiodinase (D3), which inactivates T3, are found in adjacent neurons.

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Pyroglutamyl peptidase II (PPII), a highly specific membrane-bound metallopeptidase that inactivates TRH in the extracellular space, is tightly regulated by thyroid hormone in cells of the anterior pituitary. Whether PPII has any role in the region where axons containing hypophysiotropic TRH terminate, the median eminence, is unknown. For this purpose, we analyzed the cellular localization and regulation of PPII mRNA in the mediobasal hypothalamus in adult, male rats.

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To explore the effect of refeeding on recovery of TRH gene expression in the hypothalamic paraventricular nucleus (PVN) and its correlation with the feeding-related neuropeptides in the arcuate nucleus (ARC), c-fos immunoreactivity (IR) in the PVN and ARC 2 h after refeeding and hypothalamic TRH, neuropeptide Y (NPY) and agouti-related protein (AGRP) mRNA levels 4, 12, and 24 h after refeeding were studied in Sprague-Dawley rats subjected to prolonged fasting. Despite rapid reactivation of proopiomelanocortin neurons by refeeding as demonstrated by c-fos IR in ARC alpha-MSH-IR neurons and ventral parvocellular subdivision PVN neurons, c-fos IR was present in only 9.7 +/- 1.

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To determine whether endotoxin-induced activation of type 2 iodothyronine deiodinase (D2) in the mediobasal hypothalamus is dependent on circulating levels of corticosterone, the effect of bacterial lipopolysaccharide (LPS) on D2 gene expression was studied in adrenalectomized, corticosterone-clamped adult, male, Sprague Dawley rats. In sham-adrenalectomized animals, LPS (250 microg/100 g body weight) increased circulating levels of corticosterone and IL-6, as well as tanycyte D2 mRNA in the mediobasal hypothalamus. Adrenalectomized, corticosterone-clamped animals showed no significant rise in corticosterone after LPS, compared with saline-treated controls but increased IL-6 levels and tanycyte D2 mRNA similar to LPS-treated sham controls.

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To determine whether the p44/p42 MAPK (ERK1/2) signaling pathway is involved in the activation of CRH-containing neurons in the hypothalamic paraventricular nucleus (PVN) after bacterial lipopolysaccharide (LPS) administration, Sprague Dawley rats were injected with LPS, and studied after 2, 6, 9, and 12 h. In saline-treated controls, isolated weak phosphorylated (phospho)ERK1/2 immunoreactive neurons were observed in the PVN. However, a dramatic increase in phospho-ERK1/2 immunoreactivity was apparent in the PVN 2 h after LPS administration, and gradually declined to baseline levels 9-12 h after injection.

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The testis has been classically described as a thyroid hormone unresponsive tissue, but recent studies indicate that these hormones might play an important role in developing testes. We have previously demonstrated that type 2 iodothyronine deiodinase (D2), a thyroid hormone-activating enzyme, is expressed in adult rodent testis and that its activity is induced by hypothyroidism. Nevertheless, the precise location of D2 in testis is not known.

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Neural stimuli, such as suckling or cold exposure, increase TRH mRNA in the paraventricular nucleus (PVN) of the rat hypothalamus, yet only suckling induces prolactin secretion. As TRH co-localizes with cocaine- and amphetamine-regulated transcript (CART) in hypophysiotropic neurons of the PVN, and CART inhibits TRH-induced prolactin release but not TRH-induced TSH release in adenohypophyseal cell cultures, we raised the possibility that differential regulation of CART gene expression in the PVN may explain the differences in prolactin secretion following each of the two stimuli. Primiparous female rats were mated and handled daily during the pre- and postpartum periods.

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TRH administration induces arousal, improves cognition, and modulates glutamatergic and cholinergic transmission in hippocampal neurons. To study the possible involvement of TRH neurons in learning and memory processes, gene expression of TRH, its receptors, and pyroglutamyl peptidase (PPII), were measured in limbic regions of water-maze trained rats. Hypothalamus and amygdala showed changes related to the task but not specific to spatial learning while in hippocampus, pro-TRH and TRH-R1 mRNA levels were specifically increased in those animals trained to find a hidden platform.

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To identify regions in the hypothalamus involved in refeeding and their regulation by alpha-MSH, adult rats were subjected to a 3-d fast, and 2 h after refeeding, the distribution of c-Fos-immunoreactive neurons was elucidated. Compared with fed and fasted animals, a significant increase (P < 0.001) in the number of c-Fos-immunoreactive cells was identified in refed animals in the supraoptic nucleus, magnocellular and ventral parvocellular subdivisions of the hypothalamic paraventricular nucleus (PVNv), and the dorsal and ventral subdivisions of the dorsomedial nucleus (DMNd and DMNv, respectively).

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Glucocorticoids and corticotropin-releasing hormone (CRH) are key regulators of stress responses. Different types of stress activate the CRH system; in hypothalamus, CRH expression and release are increased by physical or psychological stressors while in amygdala, preferentially by psychological stress. Learning and memory processes are modulated by glucocorticoids and stress at different levels.

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The reductions in circulating levels of leptin, insulin, and glucose with fasting serve as important homeostasis signals to neurons of the hypothalamic arcuate nucleus that synthesize neuropeptide Y (NPY)/agouti-related protein (AGRP) and alpha-MSH/cocaine and amphetamine-regulated transcript. Because the central administration of leptin is capable of preventing the inhibitory effects of fasting on TRH mRNA in hypophysiotropic neurons primarily through effects on the arcuate nucleus, we determined whether the continuous administration of 30 mU/d insulin or 648 microg/d glucose into the cerebrospinal fluid by osmotic minipump might also have similar effects on the hypothalamic-pituitary-thyroid axis. As anticipated, the intracerebroventricular infusion of leptin reduced fasting-induced elevations in NPY and AGRP mRNA and increased proopiomelanocortin and cocaine and amphetamine-regulated transcript mRNA in the arcuate nucleus.

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The purpose of this study was to determine gustatory thresholds for five different food-associated sugars in Ateles geoffroyi. Using a two-bottle test, three adult spider monkeys were found to significantly prefer concentrations as low as 3 mM sucrose, 15 mM fructose, 20 mM glucose, and 10 mM lactose over tap water. Maltose was significantly discriminated down to 20 mM with individual animals showing either a preference or an aversion, or an inverted U-shaped function of preference toward higher concentrations of this carbohydrate.

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