Navegando por Palavras-chave "parathyroid hormone"
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- ItemAcesso aberto (Open Access)Circulating forms of parathyroid hormone detected with an immunofluorometric assay in patients with primary hyperparathyroidism and in hyperparathyroidism secondary to chronic renal failure(Associação Brasileira de Divulgação Científica, 2001-12-01) Kunii, I.s. [UNIFESP]; Vieira, J.g.h. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)In patients with uremia, intact parathyroid hormone (PTH) measurement appears to overestimate the biologically active hormone in circulation. The recent description of the accumulation in these patients of a non-intact PTH form measured by the standard immunometric assays, re-opened the question. In this study we submitted serum samples from 7 patients with primary hyperparathyroidism (PHP) and from 10 patients with hyperparathyroidism secondary to chronic renal failure (SHP) to preparative HPLC in order to discriminate the molecular forms measured by our currently used immunofluorometric assay for intact PTH. The elution profile obtained with the HPLC system showed two clearly defined peaks, the first one corresponding to a lower molecular weight form, and the second to the intact PTH (1-84) form. In patients with SHP the area under the curve for the first peak (mean 29.5%, range 20.6 to 40.4%) was significantly greater than that observed for patients with PHP (mean 15.6%, range 5.6 to 21.9%). This confirms previous studies showing accumulation of molecular forms of slightly lower molecular weight, presumably PTH (7-84), in patients with SHP and, to a lesser extent, in patients with PHP. The real necessity of assays that discriminate between these two molecular forms is debatable.
- ItemAcesso aberto (Open Access)Definição de valores de corte para medida de PTH intraoperatório no tratamento cirúrgico do hiperparatiroidismo secundário e terciário(Associação Brasileira de Otorrinolaringologia e Cirurgia Cervicofacial, 2013-08-01) Ohe, Monique Nakayama [UNIFESP]; Santos, Rodrigo Oliveira [UNIFESP]; Kunii, Ilda Sizue [UNIFESP]; Carvalho, Aluizio Barbosa de [UNIFESP]; Abrahão, Márcio [UNIFESP]; Neves, Murilo Catafesta das [UNIFESP]; Lazaretti-Castro, Marise [UNIFESP]; Cervantes, Onivaldo [UNIFESP]; Vieira, Jose Gilberto Henriques [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)In order to improve success rates in surgery of renal hyperparathyroidism, we evaluated intraoperative PTH (IOPTH) measurement utility. METHOD: 86 patients underwent total parathyroidectomy with intramuscular presternal autotransplantation from 04/2000 to 10/2009 and were followed for 26.5 months on average (prospective cohort). Patients were divided in secondary (SHPT) and tertiary hyperparathyroidism (THPT). SHPT group was composed by patients under dialysis treatment, THPT group included renal grafted ones. IOPTH (Elecsys-PTH-Immunoassay/Roche) was measured at anesthesia induction (IOPTH-0') and 20 minutes (IOPTH-20') after parathyroidectomy. RESULTS: 80.2% (69/86) presented with 80% decrease or more in the IOPTH-20' and all were cured. In 11/86 patients (12.7%), a lower IOPTH-20' drop (70-79%) was observed, and 2 of them (18.1%) failed to cure. 6/86 (6.9%) patients presented IO-PTH-20' decrease of less than 70%: two were cured, in three a supernumerary/ectopic parathyroid was found and removed, and in one of these six patients, surgery was finished after 4-gland excision and the patient failure to cure. CONCLUSION: IOPTH-20' decrease of 80% or more compared to IOPTH-0' predicts cure in all renal patients throughout follow-up. A decay of less than 70% points to missed or hyperfunctioning supernumerary gland and is predictive of surgical failure in 66.6%. A marginal IOPTH drop of 70-79% leaves the decision whether or not surgery should be continued up to the experienced surgeon.
- ItemSomente MetadadadosEffects of PTH on intracellular calcium of MDCK cells in culture(Karger, 1997-01-01) Gil, Frida Zaladek [UNIFESP]; Silva, Vera Lidia Costa [UNIFESP]; Oshiro, Maria Etsuko Miyamoto [UNIFESP]; Ferreira, Alice Teixeira [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Intracellular calcium [Ca2+](i) exerts multiple functions in renal epithelia and is regulated by several hormonal factors, among them parathyroid hormone (PTH). The effect of PTH on [Ca2+](i) was investigated in Madin-Darby canine (MDCK) kidney cells in culture. Changes in [Ca2+](i) were monitored fluorometrically with the Ca2+-sensitive probe fura 2/AM, at 37 degrees C. The addition of PTH, in three cumulative doses, led to a significant and sustained raise in [Ca2+](i), in a medium with 1.36 mM [Ca2+](e). When Ca2+ was subtracted from the extracellular medium, [Ca(2+)0](e), the addition of PTH caused discrete changes on [Ca2+](i), suggesting that the hormone-induced alteration in [Ca2+](i) depend not only on [Ca2+](e), but also on intracellular stores of the ion. Nifedipine (NF) and verapamil (VP) partially blocked the PTH-induced increase in [Ca2+](i), when calcium was present in the medium, suggesting that dihydropyridine sensible-type channels are present in the plasma membrane (PM). PTH showed no effect on [Ca2+](i) in MDCK cells previously treated with 2 mu M thapsigargine (TP) in [Ca(2+)0](e) conditions but the hormone led to further fluctuations in [Ca2+](i) when [Ca2+](e) was restored to normal values. VP did not interfere with the sharp increase in [Ca2+](i) induced in cells depleted from Ca2+, which were reincubated in a normal Ca2+ medium, showing that calcium-release-activated channels (CRAC) may be also present in PM. Our results support the view that MDCK cells are responsive to PTH, and that both voltage-induced calcium channels (Ca2+-VOC) and CRAC are present in the PM of MDCK cells.
- ItemAcesso aberto (Open Access)Fórum nacional de discussão das diretrizes do KDIGO para o distúrbio mineral e ósseo da doença renal crônica (DMO-DRC): uma análise crítica frente à relidade Brasileira(Sociedade Brasileira de Nefrologia, 2010-09-01) Moysés, Rosa Maria Affonso; Cancela, Ana Ludimila Espada; Gueiros, José Edvanilson Barros; Barreto, Fellype Carvalho; Neves, Carolina Lara; Canziani, Maria Eugênia Fernandes [UNIFESP]; Oliveira, Rodrigo Bueno de; Jorgetti, Vanda; Carvalho, Aluizio Barbosa de [UNIFESP]; Universidade de São Paulo (USP); Universidade Federal de Pernambuco Hospital das Clínicas; Universidade de Picardie; Universidade Federal da Bahia; Universidade Federal de São Paulo (UNIFESP)On November 14th, 2009, the Brazilian Society of Nephrology coordinated the Brazilian Discussion Meeting on the new KDIGO (Kidney Disease: Improving Global Outcomes) guidelines. The purpose of this meeting, which was attended by 64 nephrologists, was to discuss these new guidelines from the Brazilian perspective. This meeting was supported by an unrestricted grant of the biotechnology company Genzyme, which did not have access to the meeting room or to the discussion sections. This article brings a summary of the KDIGO guidelines and of the discussions by the attendees.
- ItemSomente MetadadadosInfluence of parathyroidectomy and calcium on rat renal function(Karger, 1999-09-01) Gil, Frida Zaladek [UNIFESP]; Gomes, Guiomar Nascimento [UNIFESP]; Cavanal, Maria de Fátima [UNIFESP]; Cesar, Katia Regina; Magaldi, Antonio Jose; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)Parathyroid hormone (PTH) has multiple effects on water and electrolyte transport along the nephron. However, the influences of PTH and calcium on the urinary concentration ability are not fully understood. In this study, clearance and microperfusion studies were performed in thyroparathyroidectomized (TPTX) rats either supplemented (TPTX+Ca2+) or not with calcium added to the ingested food as CaCl2 (1.6 g/100 g). Acid-base data and renal functional parameters were measured in TPTX and TPTX+Ca2+ rats. Additional studies were performed in the isolated inner medullary collecting tubules of intact and TPTX rats to evaluate the osmotic permeability of this segment in the presence of 10(-6) MPTH added to the bath. In these experiments the possible influence of PTH on antidiuretic hormone induced changes of the osmotic permeability in TPTX and TPTX+Ca2+ rats was also investigated. In the TPTX+Ca+ group, the glomerular filtration rate increased significantly when compared to the TPTX group (6.04 +/- 0.42 vs. 4.88 +/- 0.20 ml.min(-1).kg(-1); p < 0.05), but the U/P inulin ratio remained lower than control values (30.8 +/- 1.48 vs. 54.0 +/- 3.5; p < 0.05), which suggests that normal levels of PTH are necessary to maintain the concentrating ability. In a group of TPTX rats, an acute infusion of PTH (0.5 mu g.min(-1).kg(-1)) significantly decreased the urinary flow and increased the renal plasma flow, results that agree with the vasomodulator action of this hormone on the renal vasculature. A significant increase in the fractional K+ excretion observed in the TPTX+Ca2+ group as compared with both control and TPTX, groups suggests that the excreted load of Ca2+ may interfere with tubular K+ handling in the absence of PTH. PTH (10(-6) M) added to the bath of the isolated inner medullary collecting tubules did not change the osmotic permeability, of intact, TPTX, and TPTX+Ca2+ rats. Furthermore, it did not modify the antidiuretic hormone induced changes in the osmotic permeability. These results suggest that th is seg ment of the nephron is PTH insensitive as far as water and ion transport are concerned.
- ItemSomente MetadadadosParathyroid hormone changes during phosphorus load in patients with chronic renal insufficiency with low serum parathyroid hormone or adynamic bone disease(Dustri-verlag Dr Karl Feistle, 2001-07-01) Cuppari, Lilian [UNIFESP]; Carvalho, A. B.; Lobao, RRS; Martini, Lígia Araújo [UNIFESP]; Cendoroglo, Miguel [UNIFESP]; Ventura, RTP; Draibe, Sergio Antonio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Adynamic bone disease (ABD) is frequently associated with low serum parathyroid hormone (PTH) concentrations. Many clinical and therapeutic conditions have been associated with ABD, and recently, a low phosphorus intake accompanied by low serum concentration of phosphorus and PTH has been described. Aim: To evaluate the parathyroid gland response of chronic renal insufficiency patients (CRI) with low serum PTH or ABD to a phosphorus load. Methods: We examined the effects of 0.5 and 1.0 g/d of phosphorus load over a period of 60 days in 18 patients with mild CRI with a bone biopsy showing ABD (n = 7) or with low serum PTH (serum intact PTH less than or equal to 40 ng/l) and serum phosphorus < 4.5 mg/dl (n = 11). Results: Serum intact PTH increased significantly only after I g of phosphorus (58.5 to 83 ng/l) with a median percent increase of 72%. PTH secretion increased more in patients with lower basal PTH levels (81%). Serum phosphorus did not change significantly and urinary phosphorus increased from 487 to 1062 mg/dl (p < 0.05). Significant decreases in serum ionized calcium (from 1.26 to 1.19 mmol/l) and calcitriol (from 34.5 to 24.9 pg/ml) were observed. Changes in PTH were inversely correlated with changes in serum ionized calcium (r = -0.54, p < 0.05) and the final PTH concentrations were positively correlated with changes in serum phosphorus (r = 0.52, p < 0.05). Conclusions: The parathyroid glands of chronic renal insufficiency patients with relative hypoparathyroidism or ABD responded to a phosphorus load with an increase in serum PTH levels. The decrease in serum ionized calcium and calcitriol as well as minimal changes in serum phosphorus appeared to be involved in this response.
- ItemSomente MetadadadosParathyroidectomy enhances the nephrotoxicity of gentamicin(Excerpta Medica Inc, 1997-04-01) Glashan, Regiane Q. [UNIFESP]; Silva, Vera Lidia Costa [UNIFESP]; Cavanal, Maria de Fátima [UNIFESP]; Gil, Frida Zaladek [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)The objective of this study was to evaluate the effect of parathyroidectomy on the renal function in rats treated with saline (control), low-dose gentamicin (GM, 4 mg/kg per day), or high-dose GM (40 mg/kg per day) for 10 consecutive days. Gentamicin sulfate was dissolved in saline. A group of rats were subjected to thyroparathyroidectomy (PTX) 2 to 3 days before the beginning of the GM treatment. Thyroxine (1 mu g/100 g body weight) was subcutaneously injected daily into PTX rats. in rats with saline infusion, a significant reduction in renal functional variables was obtained after PTX. When GM treatment and PTX were both present, a further impairment in the glomerular filtration rate and the urine/plasma inulin ratio was observed, suggesting additive effects. in rats infused with ammonium chloride to cause metabolic acidosis, a decline in glomerular filtration rate was obtained, a condition that was aggravated when GM treatment and PTX were both present. Acid excretion was significantly reduced in PTX groups, mainly during acidosis. in acidotic PTX rats treated with both low and high GM doses, the excreted amount of acid was strongly impaired, compared with the acidotic non-PTX GM group. These results show that in the PTX rats nephrotoxicity of GM is increased, which suggests that in this experimental model, parathyroid hormone may exert a protective effect during aminoglycoside treatment.