[Some aspects of the metabolic action of somatotropic hormone; researches on calcium and phosphorus metabolism].
Explore the source record for details and available documents.
SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Human milk promotes less than optimal growth and is associated with phosphorus deficiency and decreased bone mineralization in very-low-birth-weight (VLBW) infants. In this study, the effects of feeding premature infants either human milk (HM), fortified human milk (FHM), or special premature formula (Similac Special Care [SSC]) on growth, phosphorus metabolism, and serum type I procollagen (pColl-I-C) were evaluated. Infants fed FHM exhibited a rate of weight gain and an increase in head circumference comparable with infants fed SSC and significantly greater than infants fed HM, despite the fact that both the FHM group and the HM group demonstrated biochemical evidence of phosphorus deficiency. The pColl-I-C concentrations in VLBW infants were tenfold to 20-fold greater than concentrations in normal children older than 2 years of age. The pColl-I-C levels correlated positively with weight gain and were significantly greater in the FHM and SSC groups than in the HM group. By contrast, serum alkaline phosphatase levels did not correlate with weight gain and were significantly lower in the rapidly growing SSC group than in either of the two groups with phosphorus deficiency and presumed poor bone mineralization. We conclude that the serum pColl-I-C concentration is a biochemical marker of growth in VLBW infants and may prove useful as a predictor of growth responses to various nutritional and therapeutic interventions.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The object-oriented computing model of Smalltalk/V proved to be very well suited for the creation of a medical expert system on the diagnosis of calcium-phosphorus metabolism abnormalities. A major reason for this was that a disease could be viewed as a self-contained, active, entity. The expert system is implemented in ALEX, an expert system shell that is written in Smalltalk/V. The shell consists of classes and methods that can be modified, as needed, by the developer. The expert system is, at present, 140,000 bytes in size, and includes 43 diseases, arranged in 7 contexts. Sixty case reports were used to test the expert system. In 30 cases, there was complete agreement between clinician and expert system; in 12 cases, the expert system responded appropriately when presented with diseases that were not known to the system; and in 18 cases, the system gave plausible results.
A study was carried out in 25 patients on chronic intermittent haemodialysis on the effect of increasing the dialysate calcium concentration from 1.5 to 1.75 mMol/l on calcium and phosphorus metabolism. In 16 patients the increase in the dialysate calcium resulted in a sufficiently large increase in the plasma Ca level to suppress the parathyroid glands. The calcium influx during dialysis in these patients was sufficient to abolish the effects of diminished calcium absorption from the intestine due to loss of endocrine renal function. The remaining 9 patients showed no suppression of parathyroid gland activity and could be separated into two different groups, one requiring calcium supplementation and the other group manifesting signs of autonomic hyperparathyroidism. The five patients showing a higher calcium requirement were started on active vitamin D metabolites. In the remaining 4 patients parathyroidectomy will probably be inevitable if progression of the clinical manifestations of hyperparathyroidism occurs. Close control of plasma phosphorus levels is mandatory to avoid an increase in the calcium phosphate product or the danger of hypophosphataemic osteomalacia.
UNLABELLED: Osteoprotegerin (OPG), a member of the TNF receptor superfamily is a natural inhibitor of osteoclastogenesis and important inhibitor of vascular calcification. The aim of the study was to estimate a correlation of serum OPG level and the other parameters calcium-phosphorus metabolism in children with chronic renal failure. Seventy four children with chronic renal insufficiency, 48 on conservative treatment (CRF) aged 13 +/- 3 years with creatinine clearance 45 +/- 21 ml/min/1.73m2 and 26 with end-stage renal disease (ESRD) aged 14 +/- 5 years were examined. The control group (K) consisted of 23 healthy children aged 10.8 +/- 3 years. In all children serum concentration of OPG, calcium (sCa), phosphorus (sP), PTH, CAP (cyclase activating PTH), CIP (cyclase inactive PTH) and osteocalcin (OC) were measured. OPG was determined by ELISA method (Biomedica), PTH and OC by IRMA (Duo-PTH, Scantibodies, USA and Osteo-Riact firm CIS, F). RESULTS: The concentration of OPG was higher in ESRD group (3 +/-1.6 pmol/l) than in K (1.95 +/- 0.56 pmol/l), p<0.005. The concentration of OPG in CRF group (2.42 +/- 1.4 pmol/l) was not different from this in K and ESRD. The concentration of OPG did not correlate with serum creatinine level. In CRF group no correlation was found between OPG level and the other parameters, in group ESRD the significant correlation between OPG and OC was found (R=0.55, p=0.006). The level of OPG in children CRF + ESRD correlated with PTH concentration (R=0.27, p<0.03), CAP (R=0.29, p<0.02), CIP (R=0.23, p<0.05) and OC (R=0.25, P<0.04). In patients with higher PTH level (> 200 pg/ml) the higher correlations between OPG and PTH, CAP and CIP were found. No significant correlation between PTH and OPG in patients with lower PTH level (< 200 pg/ ml) was found. No significant correlation between OPG and OC in patients with lower and higher PTH was found. CONCLUSION: The elevated levels of OPG in children with ESRD may reflect the higher bone turnover in these patients.
The study was aimed at evaluation of the effect of short-term treatment with one of the six beta adrenolytic drugs (propranolol, metoprolol, atenolol, pindolol, nadolol, acebutolol) and calcium antagonist nifedipine on the values of several parameters of calcium-phosphorus metabolism in 81 patients with hyperthyroidism (14 patients with Graves' disease, and 67 patients with toxic nodular goiter), and 82 patients with simple goiter. The patients studied have been divided into seven groups, each receiving one of the investigated drugs during four days. A significant decrease in the urinary excretion of hydroxyproline was found only in the patients with hyperthyroidism receiving propranolol. This effect of propranolol on hydroxyprolinuria was not related to the degree of lowering of serum T3 concentration observed in these patients.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Nine healthy male volunteers were exposed to head-down tilt (-4.5 degrees) for 120 days. The concentrations of parathormone, calcitonin, gastrin, growth hormone, total and ionized calcium were measured in plasma. Prolonged exposure to antiorthostatic hypokinesia led to significant changes in the hormonal regulation of calcium-phosphorus metabolism, the most important of which was an enhanced secretion of the parathyroid hormone. The increased concentration of calcitonin and gastrin was a secondary response to the higher content of ionized calcium. The phase-like changes in the somatotrophic hormone secretion were induced by variations in the parathormone concentration in blood, on the one hand, and by a reduction of plastic processes, on the other.
Iliac-crest biopsies were obtained from 40 untreated hyperthyroid patients after double-labelling with tetracycline. Histomorphometric analyses were performed on undecalcified and decalcified bone sections. The morphometric and chemical data were compared with those in normal control groups and the results of the morphometric analyses were related to thyroid function and to chemical quantities of calcium-phosphorus metabolism. The bone turn-over was increased in the hyperthyroid patients with an increase both in bone resorption and bone formation. Serum alkaline phosphphatase was increased and positively correlated to the amount of osteoid and to the extent of tetracycline-labelled surfaces. The osteoclastic resorption was positively and the bone formation inversely correlated to thyroid activity. This might explain the reduced amount of trabecular bone found in hyperthyroidism. The most striking feature was, however, a pronounced increase in osteoclastic activity in cortical bone followed by increased porosity. The osteoclastic resorption in cortical bone was positively correlated to serum concentrations and urinary excretions of calcium and phosphorus. This indicates that increased cortical osteoclastic resorption is mainly responsible for bone mineral mobilisation in hyperthyroidism.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
In children, cardiac abnormalities such as increased left ventricular mass (LVM) and diastolic dysfunction develop at the time of mild to moderate chronic renal insufficiency (CRI) and progress as renal function deteriorates. It was hypothesized that in this age group, vascular abnormalities develop early in the course of chronic kidney disease (CKD) in parallel with cardiac abnormalities and become more severe as end-stage disease is reached. Echocardiography and ultrasound of the carotid artery were performed on 44 patients with CKD stages 2 to 4 (CRI group), 16 patients who were on maintenance dialysis, and 35 healthy individuals. Carotid artery intima-media thickness (cIMT) was measured and distensibility and stiffness were calculated to assess carotid artery structure and function. Both the CRI and dialysis groups had greater cIMT, higher LVM index, and poorer diastolic function than the control subjects (P < 0.0001). Children who were on dialysis had greater cIMT and higher LVM index than those with CRI (P < 0.001) and greater arterial stiffness than both CRI patients and control subjects (P < 0.001). Arterial compliance was similar in CRI and control subjects. In all patients with CKD (CRI and dialysis), increased calcium-phosphorus product predicted increased cIMT. Increased serum phosphorus and intact parathyroid hormone predicted increased arterial stiffness. Elevated intact parathyroid hormone was a predictor of increased LVM index and poor diastolic function. In dialysis patients, the cumulative dose of phosphate binders and calcitriol predicted abnormal vascular structure and function. It is concluded that vascular abnormalities are already present in children and adolescents during early stages of CKD; they are more severe in children who are on maintenance dialysis and are related to abnormal calcium-phosphorus metabolism.
BACKGROUND: 22-Oxacalcitriol (OCT), an analogue of vitamin D, has been shown to inhibit cell proliferation in cultured mesangial cells. OCT also prevented albuminuria and glomerular injury in an acute model of anti-Thy1 glomerulonephritis. However, potential side effects, including calcaemic actions and tubular dysfunction, of chronic OCT treatment remain unclear. In the present study, we evaluated the effect of OCT in a chronic model of progressive glomerulosclerosis in subtotally nephrectomized (SNX) rats. METHODS: At one week after subtotal nephrectomy, SNX rats were divided into 3 groups having equivalent serum creatinine levels and body weight. OCT (0.08 or 0.4 micro g/kg body weight) was administered intravenously three times per week for 8 weeks to SNX rats. We evaluated effects of OCT on renal function during treatment and on morphologic parameters in glomeruli at 8 weeks. We additionally measured calcium and phosphate levels in serum and urine, and tubular dysfunction markers, including beta(2)-microgloblin (beta(2)m) and N-acetyl-beta-D-glycosaminidase (NAG) levels in urine. RESULTS: OCT treatment significantly suppressed urinary albumin excretion, prevented increases in serum creatinine and serum urea nitrogen, and inhibited glomerular cell number, glomerulosclerosis ratio and glomerular volume in SNX rats at 8 weeks. At that time, OCT-treated groups did not show hypercalcaemia, hypercalciuria or hyperphosphaturia. Furthermore, OCT treatment did not affect beta(2)m or NAG levels in urine, and did not induce histological changes in tubular or interstitial regions. CONCLUSIONS: These findings suggest that OCT may provide a clinically useful agent for preventing the progression of glomerulosclerosis without adversely affecting calcium and phosphorus metabolism or causing subsequent tubular dysfunction.