After transplantation the kidney is subjected to rejection and other deleterious factors including ischemic damage, acute tubular necrosis, rejection and the use of cyclosporine A (CsA) or FK506. As a result, kidney damage may be generalized with azotemia as its hallmark. These tubular syndromes may cause profound changes in the acid base balance and in the level of certain blood electrolytes and minerals. As a general rule, the renal tubular acidosis (RTA) that appears early following transplantation disappears spontaneously and is predominantly a sequela to acute renal failure. On the other hand, defects occurring in the late posttransplant period are often due to chronic rejection or CsA-induced nephrotoxicity. Secondary hyperparathyroidism, urinary tract infection and obstructive uropathy may also play a contributory urinary role in the pathogenesis of RTA. Chronic RTA following transplantation may interfere with bone metabolism and at times lead to nephrocalcinosis and nephrolithiasis. Therefore, if the condition is prolonged, a supplement of bicarbonate should be given if for no other reason than to protect the skeleton. As these patients may develop either hyperkalemia or hypokalemia, treatment with potassium supplements or potassium-sparing diuretics should be carried out with caution and under constant surveillance. Furthermore, magnesium replacement may be advisable if hypomagnesemia by decreased proximal reabsorption becomes clinically evident. Tubular dysfunction may occur following renal transplantation even in patients with maintained glomerular filtration rate and may induce a number of clinical problems including deterioration of renal graft function.

Despite having good intentions, hemodialysis (HD) clinics often fail to sustain exercise programs that they initiate. There are many reasons for this, including a lack of funding, inadequate training of the clinic staff, a lack of exercise professionals to manage the program or train the staff, and the many challenges inherent to exercising a patient population with multiple comorbid diseases. Despite these barriers, there are several outstanding examples of successful exercise programs in HD clinics throughout the world. The aim of this manuscript is to review the characteristics of four successfully sustained HD exercise programs in Portugal, Canada, Mexico, and Germany. We describe the unique approaches they have used to fund and manage their programs, the varied exercise prescriptions they incorporate, the unique challenges they face, and discuss the benefits they have seen. While the programs differ in many regards, a consistent theme is that they each have substantial and committed support from the entire clinic staff, including the nephrologists, administration, nurses, dietitians, and technicians. This suggests that exercise programs in HD clinics can be successfully implemented and sustained provided significant effort is made to foster a culture of physical activity throughout the clinic.

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The calcium-dependent secretion of parathyroid hormone (PTH) is mediated through an extracellular G protein-coupled calcium receptor (CaR). Inactivating point mutations of this receptor have been found in familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism. These diseases feature a decreased calcium sensitivity of the parathyroid glands, resulting in a rightward shift of the Ca2(+)-PTH relationship. Severe non-suppressible renal hyperparathyroidism (rHPT) is often characterized by similar setpoint shifts to the right. Thus, point mutations of the CaR gene could contribute to non-suppressible rHPT. We examined genomic DNA of hyperplastic or mainly nodular tissues of 39 parathyroids from 25 rHPT-patients with resistance to calcitriol therapy. Amplification of the six exons of the CaR gene was followed by single-strand conformation polymorphism (SSCP) analysis. DNA sequencing was performed where band shifts were observed. No point mutations in the coding sequence of the CaR gene were detected using the PCR-SSCP strategy. Point mutations in the coding regions of the CaR gene probably play no role in the evolution of renal HPT and are not responsible for the calcitriol resistance of PTH secretion.

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