Browsing by Author "Uslar N., Thomas"

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    Aceptación y adherencia de una pauta de preparación de colon el mismo día del examen en población chilena
    (2015) Mansilla V., Rodrigo; Corsi S., Oscar; Glasinovic V., Esteban; Uslar N., Thomas; Monrroy Bravo, Hugo Alfonso; Candia Balboa, Roberto; González Donoso, Robinson; Álvarez Lobos, Manuel; Parra Blanco, Adolfo
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    Progressive 11β-hydroxysteroid dehydrogenase type 2 insufficiency as kidney function declines
    (2024) Uslar N., Thomas; Newman, Andrew J.; Tapia Castillo, Alejandra; Carvajal Maldonado, Cristián Andrés; Fardella B., Carlos; Allende, Fidel; Solari, Sandra; Tsai, Laura C.; Milks, Julia; Cherney, Michael; Stouffer, David G.; Auchus, Richard; Brown, Jenifer M.; Baudrand Biggs, René; Vaidya, Anand
    Background It has been postulated that chronic kidney disease (CKD) is a state of relative 11 beta-hydroxysteroid dehydrogenase type 2 (11 beta HSD2) insufficiency, resulting in increased cortisol-mediated mineralocorticoid receptor (MR) activation. We hypothesized that relative 11 beta HSD2 insufficiency manifests across a wide spectrum of progressively declining kidney function, including within the normal range. Methods Adult participants were recruited at 2 academic centers. A discovery cohort (n = 500) enrolled individuals with estimated glomerular filtration rate (eGFR) ranging from normal to CKD stage 5, in whom serum cortisol-to-cortisone (F/E) was measured as a biomarker of 11 beta HSD2 activity. A validation cohort (n = 101) enrolled only individuals with normal kidney function (eGFR >= 60 mL/min/1.73 m(2)) in whom 11 beta HSD2 activity was assessed via serum F/E and 11-hydroxy-to-11-keto androgen (11OH/K) ratios following multiple maneuvers: oral sodium suppression test, dexamethasone suppression test (DST), and ACTH-stimulation test (ACTHstim). Results In the discovery cohort, lower eGFR was associated with higher F/E (P-trend < .001). Similarly, in the validation cohort, with normal eGFR, an inverse association between eGFR and both F/E and 11OH/K ratios was observed (P-trend < .01), which persisted following DST (P-trend < .001) and ACTHstim (P-trend < .05). The fractional excretion of potassium, a marker of renal MR activity, was higher with higher F/E (P-trend < .01) and with lower eGFR (P-trend < .0001). Conclusion A continuum of declining 11 beta HSD2 activity was observed with progressively lower eGFR in individuals spanning a wide spectrum of kidney function, including those with apparently normal kidney function. These findings implicate cortisol-mediated MR activation in the pathophysiology of hypertension and cardiovascular disease in CKD.
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    Reporte de caso de feocromocitoma bilateral asociado a mutación del gen TMEM127. Primer caso chileno
    (2022) Delgado García, José Fröbel; Perez E., María Javiera; Delgado, Dasha; Lagos, Carlos; Baudrand Biggs, René; Uslar N., Thomas
    Up to 40% of Pheochromocytoma/paraganglioma syndromes are associated with germline mutations. Therefore, they are considered familial and heritable. We report a 65 year old woman with hypertension, bilateral adrenal nodules found in the CT scan and elevated urinary metanephrines. Her genetic testing showed a c.117_120delGTCT TMEM127 gene mutation. She was subjected to a laparoscopic bilateral adrenal excision. After five years of follow up, no recurrence of the disease has been recorded.
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    Sarcoid-like granulomatous myositis-associated hypercalcemia. An infrequent case to consider
    (2021) Uslar N., Thomas; Olmos Borzone, Roberto Ignacio; Godoy Santín, Jaime; Mellado T., Patricio; González Vicente, Gilberto
    PTH-independent hypercalcemia due to granulomatous disease is well-documented and sarcoidosis is the most characteristic disease, although there are others. We describe a case of sarcoid-like granulomatous myositis. An 87-year-old man was referred with tetraparesis and hypercalcemia (albumin-corrected calcium of 13.4 mg/dl) following a trip to the Caribbean. The evaluation showed a suppressed PTH, 25-hydroxy vitamin D of 7.5 ng/ml, 18F-FDG PET/CT showed markedly increased uptake in intercostal, back, shoulder, buttock and thigh muscles and a deltoid biopsy confirmed extensive granulomatous myositis. He was prescribed glucocorticoids which resulted in normalized plasma calcium levels and complete recovery from tetraparesis. Sarcoid-like granulomatous myositis should be incorporated into the differential diagnosis of PTH-independent hypercalcemia, especially in the absence of clinical features of sarcoidosis and with special emphasis on the use of 18F-FDG PET/CT to ensure a correct approach.
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    The role of sex hormones in aldosterone biosynthesis and their potential impact on its mineralocorticoid receptor
    (2024) Vecchiola Cárdenas, Andrea Paola; Uslar N., Thomas; Friedrich, Isidora; Aguirre, Joaquín; Sandoval, Alejandra; Carvajal, Cristian A.; Tapia Castillo, Alejandra; Martínez García, Alejandra Constanza; Fardella B., Carlos
    Blood pressure (BP) regulation is a complex process involving various hormones, including aldosterone and its mineralocorticoid receptor. Mineralocorticoid receptor is expressed in several tissues, including the kidney, and plays a crucial role in regulating BP by controlling the sodium and water balance. During different stages of life, hormonal changes can affect mineralocorticoid receptor activity and aldosterone levels, leading to changes in BP. Increasing evidence suggests that sex steroids modulate aldosterone levels. Estrogens, particularly estradiol, mediate aldosterone biosynthesis by activating classical estrogen receptors and the G protein-coupled receptor. Progesterone acts as an anti-mineralocorticoid by inhibiting the binding of aldosterone to the mineralocorticoid receptor. Moreover, progesterone inhibits aldosterone synthase enzymes. The effect of testosterone on aldosterone synthesis is still a subject of debate. However, certain studies show that testosterone downregulates the mRNA levels of aldosterone synthase, leading to decreased plasma aldosterone levels.
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    Validez y confiabilidad de una escala de clasificación de limpieza gástrica en endoscopia digestiva alta en población chilena
    (2016) Mansilla V., Rodrigo; Uslar N., Thomas; Chahuán A., Javier; Latorre S., Gonzalo; Cruz N., Rodrigo; Cruz Urrutia, Ricardo Javier; Sirhan Nahum, Marisol; Espino Espino, Alberto Antonio; Honold G., Francisca; Huenur F., Julieth; Miranda B., Paula; Riquelme Pérez, Arnoldo