Childhood renal osteodystrophy

Chronic renal insufficiency is characterized by profound alterations in the orderly metabolic sequences which normally guarantee cellular integrity and metabolic homeostasis. Hormonal imbalances which contribute to these acquired defects include abnormal growth hormone secretory patterns, elevations in plasma aldosterone and glucagon, decreases in testosterone and thyroid hormone, and defective biological degradation of Cortisol, insulin, and parathyroid hormone. These findings are often coupled with blunted end-organ responsivity to hormonal stimulation, e.g., insulin, and contribute to the disturbances in carbohydrate and lipid metabolism and to defective synthesis and catabolism of structural and enzymatic proteins. The normal kidney functions as a biological filter by regulating the excretion of a variety of substances, normally generated by either biological synthetic or degradative reactions. These products can function as metabolic “toxins” when retained by the body in sufficient quantities.The kidney also occupies a pivotal role in the regulation of calcium, inorganic phosphate, parathyroid hormone, calcitonin, and vitamin D metabolism. Adults and children with progressive loss of renal parenchyma sustain derangements in mineral and bone metabolism with resultant osteodystrophy. Children experience abnormalities in growth and remodeling of bone as well. These changes may progress to a renal osteodystrophy characterized by growth retardation and bone pain. Hyperparathyroidism and deficiency in biological activation of vitamin D are the basic pathophysiologic mechanisms involved. The requirement of vitamin D or its biologically more active forms is increased. In this review, normal bone development is described as a basis for interpreting the pathophysiology of renal osteodystrophy in children. Because renal osteodystrophy is often termed “renal rickets” and the processes of osteodystrophy and rickets differ, the evolution of the histological changes of each are contrasted. Some of the ways renal osteodystrophy affects growth are explained by the evolution of these processes.The unique features of childhood renal osteodystrophy relate to distinctions between the effects uremia has on the fully grown skeleton and growing bone. Understanding the development of bone is important to the understanding of bone disease and growth retardation which occurs in children with uremia

A new phase in water resource allocation : the case for groundwater markets in Texas

textThis report explores the application of a market framework to allocating water resources, with a specific focus on groundwater resources in Texas. Water markets have been touted by economists as an efficient and effective means of reallocating a scarce natural resource and have been implemented in various forms across the western United States. This report discusses the characteristics of water markets that allow them to efficiently allocate water resources as well as the need for institutional oversight to address negative externalities, including environmental and third party impacts. A description of Texas law and regulation of groundwater resources is also given and analyzed in the context of establishing widespread groundwater markets in the state. Several case studies, both in Texas and in other western states, are also analyzed to determine best practices for the creation of a statewide system of groundwater marketing. The report concludes with several recommendations based on these case study analyses and in light of the current legal and regulatory obstacles to widespread water markets in Texas.Architectur

Defect Characterization-Fundamental Flaw Classification Solution Potential

Pattern recognition techniques are currently being applied to many signal interpretation problems in nondestructive testing. Simulearning technology combines various aspects of wave propagation analysis, pattern recognition philosophy, and signal processing theory in such a way as to outline procedures and establish guidelines for solving many problems in flaw classification. A portion of this paper will be used to present flaw classification problem statements and potential solution techniques along with simple data and analysis techniques

Occult Cushing\u27s Syndrome Presenting with Osteoporosis

Osteoporosis is a frequent complication both of endogenous hypercortisolism and of long-term treatment with corticosteroids, but only rarely is it the major clinical feature with the more characteristic features absent or minimally present. In the two patients presented, hypercortisolism was uncovered only during routine evaluation of osteoporosis. This presentation is probably due to slow progression of the disease and is often associated with so-called black adenoma of the adrenal gland. Secondary causes should be sought in all patients with seemingly senile or postmenopausal osteoporosis

Status of Advanced UT Systems for the Nuclear Industry

An advanced ultrasonic testing (UT) system is a configuration of hardware that includes some type of computer. The computer may be hardwired to perform specific functions or have appropriate software. It may typically be used for data acquisition, signal processing, image generation, pattern recognition and data analysis. Additionally, advanced systems have data storage and are, therefore, different from the standard transducer-pulser/receiver systems that rely on human filtering and written documentation of the filtered data.</p

Evidence for Extrarenal Production of 1a,25-Dihydroxyvitamin D in Man

Recent studies provide evidence for extrarenal production of 1a,25-dihydroxyvitamin D [1a,25(OH)2D]. To investigate this possibility, serum vitamin D, 25-hydroxyvitamin D (25-OHD), 24,25-dihydroxyvitamin D [24,25(OH)2D], and 1a,25(OH)2D were measured in eight adult anephric subjects. All were undergoing hemodialysis and three of them were receiving vitamin D, 50,000 or 100,000 U/d. Serum vitamin D was elevated in two of the patients given vitamin D and was abnormally low in the others. Mean serum 25-OHD was increased in patients given vitamin D (94.0±7.6 ng/ml) and was normal in the others (16.4±0.9 ng/ml, P \u3c 0.001). Mean serum 24,25(OH)2D was normal in patients given vitamin D (1.38±0.27 ng/ml) and was low in the others (0.25±0.08 ng/ml, P \u3c 0.001). Serum 24,25(OH)2D correlated significantly with serum 25-OHD (r = 0.848, P \u3c 0.01). Mean serum 1a,25(OH)2D determined by receptor assay was 5.8±1.9 pg/ml in patients who were not given vitamin D and was 14.1±0.6 in those who were given vitamin D (P \u3c 0.001). Serum 1a,25(OH)2D correlated significantly with serum 25-OHD (r = 0.911, P \u3c 0.01). Mean serum 1a,25(OH)2D, measured by bioassay, was 8.3±1.9 pg/ml in patients who were not given vitamin D and was 15.9±2.4 pg/ml in those who were given vitamin D (P \u3c 0.05). There was a significant correlation between the values for serum 1a,25(OH)2D obtained with the two methods (r = 0.728, P \u3c 0.01). The results (a) provide evidence in man for extrarenal production of both 24,25(OH)2D and, by two independent assays, of 1a,25(OH)2D, and (b) indicate that serum values of the two dihydroxy metabolites of vitamin D in anephric subjects vary with the serum concentration of the precursor 25-OHD

Serum Calcium to Phosphorous (Ca/P) Ratio is a simple, inexpensive, and accurate tool in the diagnosis of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) diagnosis is challenging and is based on serum calcium (Ca) and parathyroid hormone (PTH). Because serum Ca and phosphorous (P) are inversely related in PHPT, we investigated the diagnostic value of the serum Ca/P ratio in the diagnosis of PHPT. We report a single-center, case-controlled, retrospective study including 97 patients with documented PHPT and compared them with those of 96 controls (C). The main outcome measures were: serum PTH, 25-OH vitamin D, Ca, P, albumin, and creatinine. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the serum Ca/P ratio were calculated. The results were verified using an independent, anonymous set of data extracted from a laboratory database containing over 900 million entries. A total of 35 (36.1%) PHPT patients had normocalcemic PHPT (NCHPT). Ca and PTH were significantly higher in PHPT than in C (p < 0.0001). P was significantly lower in PHPT than in C (p < 0.0001). The Ca/P ratio was significantly higher in PHPT than in C (p < 0.0001). Receiver-operating characteristic (ROC) curves analyses identified a cutoff of 2.71 (3.5 if Ca and P are expressed in mg/dL) for Ca/P ratio with a sensitivity and specificity of 86% and 87%, respectively (p < 0.0001), confirmed by the independent, big data approach. In conclusion, Ca/P is a valuable tool for the diagnosis of PHPT and is of superior value compared to serum Ca alone, especially in NCPHT. Because Ca/P is simple, inexpensive, and easily accessible worldwide, this ratio is useful for PHPT diagnosis, especially in laboratory/medical settings relying on limited resources, such as low-income countries. © 2017 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research