Dynamics of Parathyroid Hormone Secretion After Total Parathyroidectomy and Autotransplantation

Secondary hyperparathyroidism is a common complication in uremic patients. Total parathyroidectomy combined with partial autotransplantation into brachioradialis muscle has been the preference among the options for surgical treatment. This study was designed to evaluate the reserve and ability of suppression of autotransplanted parathyroid tissue using dynamics tests. We studied, prospectively, 12 patients in recent (RP) and late (LP) postoperative of total parathyroidectomy with autotransplantation. For analysis of the secretory reserve capacity, we induced hypocalcemia by ethylenediaminetetraacetic acid (EDTA) infusion. Furthermore, for analysis of the ability for parathyroid hormone (PTH) suppression, the hypercalcemia test was used, by intravenous administration of calcium in LP. In RP, there was a decrease in the average serum levels of PTH, phosphorus, and alkaline phosphatase, which ranged from 13 to 231 (87 +/- A 65) pg/ml, 2.3 to 6.2 (3.3 +/- A 1.1) mg/dl, and 77 to 504 (250 +/- A 135) U/L, respectively, similar to that observed in LP. The analysis of the average curve of variations in PTH during testing of the stimulus with EDTA showed lack of secretion in RP and partial response in LP. Impaired suppression ability of the graft in LP was observed in the test with intravenous calcium. Total parathyroidectomy followed by partial autotransplantation was effective in reducing PTH serum levels in patients with terminal kidney disease. The elevation of serum calcium during the suppression test was not able to inhibit the autograft gland secretion of PTH. The assessment of parathyroid graft function demonstrated an inability to respond to the stimulus of hypocalcemia induced by EDTA, although there was a partial recovery, in late postoperative period.

Glucocorticoid resistance in dialysis patients may impair the kidney allograft outcome

This study examines in vitro steroid sensitivity in chronic renal failure ( CRF) patients and its influence on the allograft outcome. We determined the inhibitory effect of dexamethasone ( DEX) on concanavalin A ( Con-A)-stimulated peripheral blood mononuclear cell ( PBMC) proliferation, and glucocorticoid receptor` ( GR) number of binding sites ( B-max) and affinity ( K-d) in 28 CRF patients and 40 normal healthy controls. Based on K-d values > 95th percentile from controls, patients were divided into two groups: glucocorticoid resistant ( n = 11) and glucocorticoid sensitive ( n = 17). Patients were followed during 18 months post-transplantation observing acute rejection episodes ( ARE), chronic allograft nephropathy ( CAN), allograft failure and death. The DEX concentration that caused 50% inhibition of Con-A-stimulated PBMC proliferation ( IC50) was higher in CRF than in healthy controls ( 2.2 x 10(-5) +/- 1.0 x 10(-5) versus 8.3 x 10(-6) +/- 4.2 x 10(-6) mol/ L, P = 0.02). Values of Kd ( 12.4 +/- 1.8 versus 7.2 +/- 0.9 nM) and Bmax ( 7.7 +/- 1.1 versus 4.1 +/- 0.3 fmol/ mg protein) were higher in CRF patients ( P = 0.02 and P = 0.001, respectively). There were higher incidences of ARE ( P = 0.02) and CAN ( P = 0.002) in the glucocorticoid-resistant group. Univariate and multivariate logistic regression showed that Kd was an independent predictor of ARE ( OR 8.8, P= 0.03) aswell as of CAN ( OR 16.5, P= 0.01). In conclusion, we observed glucocorticoid resistance in a subgroup of CRF patients undergoing dialysis, which led to a higher morbidity due to ARE and CAN in an 18-month follow-up period.

Using postoperative cardiac troponin-I (cTi) levels to detect myocardial ischaemia in patients undergoing vascular surgery

Background, Cardiac complications occur commonly in vascular surgery patients. Diagnosis of cardiac complications is difficult because of the inaccuracies associated with traditional cardiac enzyme measurements. CTi, a highly sensitive and specific marker of myocardial injury, may be able to detect cardiac complications with greater ease and accuracy. Methods. The study prospectively examined 100 consecutive patients who underwent major vascular surgery between 6/7/98 and 31/12/98 at the Royal Brisbane Hospital. Daily measurements of cTi, creatine kinase (CK), creatine kinase MB (CKMB), CKMB index, renal function and haemoglobin were taken for three postoperative days. One postoperative electrocardiograph (ECC) was taken. An extensive cardiac history was taken. Intraoperative and postoperative events were recorded. Findings. There were 100 patients, 18 patients (18%) had a cTi elevation. On the basis of classical diagnostic criteria, 15 patients (15%) suffered one or more cardiac complication (either myocardial infarction, congestive cardiac failure, unstable angina or atrial fibrillation), One patient (1%) who had a cTi elevation died. CTI elevation occurred in five patients (5%) who were not diagnosed with cardiac complications based on traditional criteria. Despite not meeting specific diagnostic criteria for cardiac complications, all patients showed signs and symptoms that could be attributed to myocardial ischaemia, Every patient who developed congestive cardiac failure or atrial fibrillation had a cTi elevation. A Chi-square analysis revealed a significant association between cTi elevation and postoperative cardiac complications. Four variables contributed small but significant amounts of unique variance to the prediction of peak cTi on linear regression analysis. These were peak CKMB index, postoperative congestive cardiac failure, postoperative chest pain and postoperative cardiac complications. Conclusions. Routine cTi monitoring of postoperative vascular patients would be an effective and inexpensive way to detect patients with cardiac complications. The relationship between postoperative cTi elevation and significant coronary artery disease remains to be shown, (C) 2001 The international Society for Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights reserved.

Nocardia asteroides peritonitis during continuous ambulatory peritoneal dialysis

This paper reports a case of peritonitis by Nocardia asteroides during continuous ambulatory peritoneal dialysis in a man who had systemic lupus erythematous and chronic renal failure. Diagnosis was established by microscopic examination (Gram and Kinyoun) and culture of centrifuged dialysis fluid and the patient was treated with Trimethoprin-Sulfamethoxazole by intraperitoneal route.

PREVALENCE OF INTESTINAL PARASITISM AND ASSOCIATED SYMPTOMATOLOGY AMONG HEMODIALYSIS PATIENTS

Intestinal parasites are an important cause of morbidity and mortality. Immunocompromised individuals may develop more severe forms of these infections. Taking into account the immunity impairment in patients suffering from chronic renal failure (CRF), we will determine the prevalence and associated symptoms of intestinal parasites in these patients. Controls without CRF were used for comparison. Stool samples were collected and processed for microscopic identification of parasites using the Formalin-ether concentration method. For Cryptosporidium diagnosis, the ELISA technique was used. One hundred and ten fecal samples from hemodialysis patients were analyzed, as well as 86 from a community group used as control group. A result of 51.6% of intestinal parasites was observed in hemodialysis patients and 61.6% in the control group. Cryptosporidium and Blastocystis were the most common infections in patients with CRF (26.4% and 24.5%, respectively). Blastocystis was the most common infection in the control group (41.9%), however no individual was found positive for Cryptosporidium. Among the CRF patients, 73.6% were symptomatic, 54.3% of these tested positive for at least one parasite, in contrast to 44.8% in asymptomatic patients (p = 0.38). The most common symptoms in this group were flatulence (36.4%), asthenia (30.0%) and weight loss (30.0%). In the control group, 91.9% were symptomatic, 60.8% of these tested positive for at least one parasite, in contrast to 71.4% in asymptomatic patients (p = 0.703). A significant difference between the two groups was observed with regard to symptoms, with bloating, postprandial fullness, and abdominal pain being more frequent in the control group than in the hemodialysis group (all p < 0.05). Comparing symptomatic with asymptomatic, there was no association in either group between symptoms or the prevalence of parasitic infection, nor with the type of parasite or with multiple parasitic infections. Patients with chronic renal failure are frequent targets for renal transplantation, which as well as the inherent immunological impairment of the disease itself, results in immunosuppression by medication. For this reason, carriers of intestinal parasites with pathogenic potential can develop serious clinical complications influencing the success of transplantation. This fact, coupled with the high prevalence of intestinal parasites and the dissociation between symptoms and infection in CRF patients, suggests that the stool test should be incorporated in routine propedeutics. Furthermore, preventive measures for the acquisition of parasites through the fecal-oral contamination route should be introduced.

Collapsing Glomerulopathy. A Treatable Disease?

Renal disease is a relatively common complication in human immunodeficiency virus (HIV) infected patients and has become the fourth leading cause of death in AIDS individuals, immediately following septicaemia, pneumonia and hepatic disease. HIV associated nephropathy, HIV associated immune complex renal disease and HIV associated thrombotic microangiopathy are the main causes of chronic renal failure in this population. The authors report a case of a 44 year-old black male, HIV 1 infected with low CD4 count, admitted to the nephrology department with non nephrotic proteinuria and renal failure. Renal biopsy revealed a focal segmental glomerulosclerosis collapsing variant. The patient was treated with highly active antiretroviral therapy and an ACE inhibitor and, at 3 months of follow-up, has recovered his renal function. This case illustrates the efficacy of highly active antiretroviral therapy (HAART) on HIV associated nephropathy. Prospective studies are needed to evaluate HAART in the treatment of HIV associated nephropathies.

Progression of Blood Pressure and Cardiovascular Outcomes in Hypertensive Patients in a Reference Center

Background: Hypertension is a public health problem, considering its high prevalence, low control rate and cardiovascular complications. Objective: Evaluate the control of blood pressure (BP) and cardiovascular outcomes in patients enrolled at the Reference Center for Hypertension and Diabetes, located in a medium-sized city in the Midwest Region of Brazil. Methods: Population-based study comparing patients enrolled in the service at the time of their admission and after an average follow-up of five years. Participants were aged ≥18 years and were regularly monitored at the Center up to 6 months before data collection. We assessed demographic variables, BP, body mass index, risk factors, and cardiovascular outcomes. Results: We studied 1,298 individuals, predominantly women (60.9%), and with mean age of 56.7±13.1 years. Over time, there was a significant increase in physical inactivity, alcohol consumption, diabetes, dyslipidemia, and excessive weight. As for cardiovascular outcomes, we observed an increase in stroke and myocardial revascularization, and a lower frequency of chronic renal failure. During follow-up, there was significant improvement in the rate of BP control (from 29.6% to 39.6%; p = 0.001) and 72 deaths, 91.7% of which were due to cardiovascular diseases. Conclusion: Despite considerable improvements in the rate of BP control during follow-up, risk factors worsened and cardiovascular outcomes increased.

Uncontrollable hypertension in patients on hemodialysis: long-term treatment with captopril and salt subtraction

It has been suggested that an inappropriate relationship between renin and exchangeable sodium is responsible for the hypertension of patients with chronic renal failure. Long-term blockade of the renin system by captopril made it possible to test this hypothesis in 8 patients on maintenance hemodialysis. Captopril was administered orally in 2 daily doses of 25 to 200 mg. Previously, blood pressure averaged 179/105 +/- 6/3 (mean +/- SEM) pre- and 182/103 +/- 7/3 mm HG post-dialysis, despite intensive ultrafiltration and conventional antihypertensive therapy. The 4 patients with the highest plasma renin activity normalized their blood pressure with captopril alone, whereas in the 4 remaining patients, captopril therapy was complemented by salt subtraction which consisted in replacement of 1-2 liters of ultrafiltrate by an equal volume of 5% dextrose until blood pressure was controlled. After an average treatment period of 5 months, blood pressure of all 8 patients was reduced to 134/76 +/- 7/5 mm Hg (P less than 0.001) pre- and 144/81 +/- 9/5 mm Hg (P less than 0.001) post-dialysis without a significant change in body weight. The present data suggest that captopril alone or combined with salt subtraction normalizes blood pressure of patients on chronic hemodialysis with so called uncontrollable hypertension.

Estudio longitudinal del Índice de masa corporal (IMC) en pacientes en diálisis

Chronic renal failure is commonly related to hyponutrition, affecting approximately on third of patients with advanced renal failure. We carried out a longitudinal study to assess nutritional evolution of 73 patients on a regular hemodialysis program, assessing changes in the anthropometrical parameter body mass index (BMI) and its correspondence to biochemical nutritional parameters such as total protein (TP) levels and serum albumin (Alb). Every three months plasma TP and albumin levels were collected and BMI was calculated by the standard formula: post-dialysis weight in kg/height in m2. For classifying by BMI categories, overweight and low weight were defined according to the WHO Expert Committee. Studied patients had a mean age of 53 years, 43 were male and 30 were female patients. BMI in women was lower than that in men (p < 0.001), as well as TP (p < 0.001) and Alb (p < 0.001) levels. Mean BMI was 29.3 kg/m2. Three point two percent of the determinations showed low weight, 12.16% overweight, and 83.97% normal BMI. TP were normal in 90.76% and decreased in 9.24%. Alb was normal in 82.2% and low in 17.78%. After the follow-up time (21.6 months, minimum 18 months, maximum 53 months), the Kruskal-Wallis test did not show a statistically significant change for BMI but it did show a change for the biochemical parameters albumin and total proteins (p < 0.05): nutritional impairment in CRF patients is manifested on biochemical parameters (TP and Alb) with no reflection on anthropometrical data.

Detection of erythropoiesis-stimulating agents in human anti-doping control: past, present and future.

Stimulation of erythropoiesis is one of the most efficient ways of doping. This type of doping is advantageous for aerobic physical exercise and of particular interest to endurance athletes. Erythropoiesis, which takes place in bone marrow, is under the control of EPO, a hormone secreted primarily by the kidneys when the arterial oxygen tension decreases. In certain pathological disorders, such as chronic renal failure, the production of EPO is insufficient and results in anemia. The pharmaceutical industry has, thus, been very interested in developing drugs that stimulate erythropoiesis. With this aim, various strategies have been, and continue to be, envisaged, giving rise to an expanding range of drugs that are good candidates for doping. Anti-doping control has had to deal with this situation by developing appropriate methods for their detection. This article presents an overview of both the drugs and the corresponding methods of detection, and thus follows a roughly chronological order.

Osteoprotegerin and bone mineral density in hemodiafiltration patients.

A newly identified cytokine, osteoprotegerin (OPG) appears to be involved in the regulation of bone remodeling. In vitro studies suggest that OPG, a soluble member of the TNF receptor family of proteins, inhibits osteoclastogenesis by interrupting the intercellular signaling between osteoblastic stromal cells and osteoclast progenitors. As patients with chronic renal failure (CRF) often have renal osteodystrophy (ROD), we investigated the role of osteoprotegerin (OPG) in ROD, and investigated whether there was any relationship between serum OPG, intact parathyroid (PTH) (iPTH), vitamin D, and trabecular bone. Serum OPG combined with iPTH might be a useful tool in the noninvasive diagnosis of ROD, at least in cases in which the range of PTH values compromises reliable diagnosis. Thirty-six patients on maintenance hemodiafiltration (HDF) and a control group of 36 age and sex matched healthy subjects with no known metabolic bone disease were studied. The following assays were made on serum: iPTH, osteocalcin (BGP), bone alkaline phosphatase, 25(OH)-cholecalciferol, calcium, phosphate, OPG, IGF-1, estradiol, and free testosterone. Serum Ca++, P, B-ALP, BGP, IGF-1, iPTH, and OPG levels were significantly higher in HDF patients than in controls, while DXA measurements and quantitative ultrasound (QUS) parameters were significantly lower. On grouping patients according to their mean OPG levels, we observed significantly lower serum IGF-1, vitamin D3 concentrations, and lumbar spine and hip bone mineral density in the high OPG groups. No correlation was found between OPG and bone turnover markers, whereas a negative correlation was found between serum OPG and IGF-1 levels (r=-0.64, p=0.032). Serum iPTH concentrations were positively correlated with bone alkaline phosphatase (B-ALP) (r=0.69, p=0.038) and BGP (r=0.92, p<0.001). The findings made suggest that an increase in OPG levels may be a compensatory response to elevated bone loss. The low bone mineral density (BMD) levels found in the high OPG group might have been due to the significant decrease in serum IGF-1 and vitamin D3 observed. In conclusion, the findings made in the present study demonstrate that increased OPG in hemodiafiltration patients is only partly due to decreased renal clearance. As it may partly reflect a compensatory response to increased bone loss, this parameter might be helpful in the identification of patients with a marked reduction in trabecular BMD.

Estudio del síndrome metabólico y de la obesidad en pacientes en hemodiálisis.

INTRODUCTION: The metabolic syndrome (MS) consists of a set of clinical and biochemical changes. It is very common among chronic hemodialysis patients, being the leading cause of death in these patients, 44% of all patients undergoing this therapy. AIMS: The aim of this study was to investigate the prevalence of MS and risk factors associated with its development, as well as the prevalence of obesity in HD patients. METHODS: This study has followed 90 patients of both sexes with chronic renal failure (CRF) who were treated with hemodialysis periodically in our unit for ten years. All patients were performed quarterly measurements of plasma albumin (A1b) and other biochemical analysis; besides, they underwent some anthropometric measurements like weight, height and body mass index (BMI). This was calculated using weight / size2 formula and grouped in BMI values according to WHO criteria. The data concerning hypertension and glucose were also considered. RESULTS: The prevalence of MS was 25% and obesity was presented as follows: 45% with type I overweight; 30.8% with type II overweight and 12 patients (2%) were obese. Being statistically significant as risk factors, BMI, overweight, triglycerides, total cholesterol, HDL cholesterol as well as hypertension and elevated glucose levels were obtained. CONCLUSIONS: The metabolic syndrome compromises the patient survival causing a high prevalence in these patients. The principal risk factors in MS are monitoring weight, BMI, triglycerides, HDL cholesterol, hypertension and diabetes.

Estudio de la albúmina sérica y del índice de masa corporal como marcadores nutricionales en pacientes en hemodiálisis.

Background: Protein calorie malnutrition as well as systemic inflammation and metabolic disorders are common among patients with chronic renal failure undergoing renal replacement therapy (haemodialysis), which contributes to its morbidity and mortality. Aims: The aims of this work was to evaluate the nutritional status of patients in a hemodialysis treatment through the assessment of biochemical parameters nutritional as albumin, and anthropometric parameters of body mass index during ten years of follow up. Methods: In this work has been followed 90 patients of both sexes with chronic kidney disease who were treated with hemodialysis regularly on our unit for ten years. All patients were conducted quarterly measurements of plasma albumin (Alb), and other biochemical determinations, and anthropometric measurements of height, weight and body mass index calculated by the formula weight/height², grouped n BMI < 23 kg/m2 and albumin levels <3.8 g/dl according to the consensus of the panel of experts of the International Society for renal Nutrition and metabolism. Results: During the 10 years all patients showed a significant decline in the biochemical parameters and the albumin, change in BMI does not presented significant changes in relation to malnutrition. Conclusions: Malnutrition in patients on dialysis is a fact patent, BMI does not correspond with the biochemical parameters were observed, for what nutritional impairment in these patients is mainly expressed by serum albumin.

Evaluation of two HbA1c point-of-care analyzers.

BACKGROUND Measurement of HbA1c is the most important parameter to assess glycemic control in diabetic patients. Different point-of-care devices for HbA1c are available. The aim of this study was to evaluate two point-of-care testing (POCT) analyzers (DCA Vantage from Siemens and Afinion from Axis-Shield). We studied the bias and precision as well as interference from carbamylated hemoglobin. METHODS Bias of the POCT analyzers was obtained by measuring 53 blood samples from diabetic patients with a wide range of HbA1c, 4%-14% (20-130 mmol/mol), and comparing the results with those obtained by the laboratory method: HPLC HA 8160 Menarini. Precision was performed by 20 successive determinations of two samples with low 4.2% (22 mmol/mol) and high 9.5% (80 mmol/mol) HbA1c values. The possible interference from carbamylated hemoglobin was studied using 25 samples from patients with chronic renal failure. RESULTS The means of the differences between measurements performed by each POCT analyzer and the laboratory method (95% confidence interval) were: 0.28% (p<0.005) (0.10-0.44) for DCA and 0.27% (p<0.001) (0.19-0.35) for Afinion. Correlation coefficients were: r=0.973 for DCA, and r=0.991 for Afinion. The mean bias observed by using samples from chronic renal failure patients were 0.2 (range -0.4, 0.4) for DCA and 0.2 (-0.2, 0.5) for Afinion. Imprecision results were: CV=3.1% (high HbA1c) and 2.97% (low HbA1c) for DCA, CV=1.95% (high HbA1c) and 2.66% (low HbA1c) for Afinion. CONCLUSIONS Both POCT analyzers for HbA1c show good correlation with the laboratory method and acceptable precision.

Résistance aux diurétiques de l'anse en clinique [Resistance to loop diuretics in clinical practice]

Loop diuretics belong to the most common medications used in ambulatory and hospitalized patients, especially in situation of hypervolemia and chronic renal failure. Prolonged used of these agents in particular medical conditions can lead to attenuation of their diuretic effect, commonly known as "resistance" to diuretics. This article intends to review the main mechanisms of resistance to loop diuretic and the ways to counteract them in clinical practice.