Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q92565 (GFR)
 4,179 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Conservative management of chronic renal failure in children is essentially based on dietary prescription including recommendations for high caloric intake and a certain limitation of protein intake according to GFR in order to avoid any extra loading with nitrogen wastes. Prescriptions for sodium potassium and water have to be adjusted on their residual output. Prevention of osteodystrophy needs supplement of calcium, chelation of phosphorus with aluminium hydroxide and the prescription of vitamin D or its active derivatives. High blood pressure when present must be carefully controlled. Drugs, when necessary, have to be given with a dosage taking into account the level of renal failure. Finally, the mode of life of the uremic child should be as close to normal as possible.
 ...
PMID:Conservative treatment of chronic renal insufficiency in children. 4 67

This experiment was designed to test whether protein consumption reduces the amount of filtered calcium reabsorbed by the kidney. Nine subjects were each fed meals containing 18 g protein and 54 g protein. The intake of energy, sodium, calcium, phosphorus, magnesium and zinc was similar in the two meals. For 4 hours after the meal, measurements were made of serum calcium (total and filterable), serum creatinine, and urinary calcium, creatinine, zinc and nitrogen. Calcium reabsorption was calculated in five clearance periods, as (filterable calcium X GFR) minus urinary calcium. Urinary calcium, zinc and nitrogen were significantly higher between 2 and 4 hours after consumption of the high protein meal. Protein level did not affect urine pH or volume, serum total or filterable calcium & or GFR. The percentage reabsorption of filtered calcium was significantly lower 0.5 hours after the high protein meal, so that at 2.5 hours, reabsorption was 98.0% compared to 98.7% after the lower protein meal. We conclude that protein consumption reduces the amount of calcium reabsorbed by the kidney.
 ...
PMID:Reduction of renal calcium reabsorption in man by consumption of dietary protein. 45 88

In rats with renal failure produced by excision of one kidney and infarction of large portions of the other kidney, given a low calcium, high phosphorus diet for 2-3 weeks, GFR was reduced by 80 percent, the fractional excretion of sodium increased from 7 to 23 percent, that of bicarbonate from 16 to 23 percent and that of water from 4 to 13 percent. Single nephron GFR in the remaining nephrons was nearly doubled and end-proximal TF/P(In) was depressed from 2.3 to 1.8, and proximal TF/P(HCO3) from 0.52 to 0.35, the latter figure corresponding to an increase of absolute proximal HCO(3) reabsorption from 1.7 to 3.5 nEq/min or from 2.8 to 3.2 Eq/L of single nephron glomerular filtrate. Acute parathyroidectomy had no influence on the fall of GFR or the rise of SNGFR in the remaining nephrons and failed to cause any significant changes in proximal tubular bicarbonate reabsorption. Parathyroidectomy, on the other hand, practically prevented the rise of the fractional excretion of sodium and of water and inverted the rise of the fractional excretion of bicarbonate to a fall. The data are interpreted to indicate that secondary hyperparathyroidism in renal failure impairs distal nephron bicarbonate and sodium reabsorption and, thus, contributes to the maintenance of sodium balance, but could possibly aggravate acidosis.
 ...
PMID:A micropuncture study of HCO3 reabsorption by the hypertrophied proximal tubule. 73 50

In chronic uremia, the clinical disorders o calcium and phosphorus metabolism are influenced by the following factors: (1) intestinal absorption of calcium and phosphate, resulting in a negative calcium and phosphate balance at normal dietary intakes; (2) renal handling of calcium and phosphate: the fractional transport of calcium (the isoosmotic reabsorption taking place in the proximal tubule) is not affected by GFR modifications, whereas the Tm-limited reabsorption is severely impaired; the external phosphate balance is kept, even in the presence of a reduced nephron population, by means of a proportional reduction in TmPO4 values; (3) physiochemical state and turnover of body calcium and phosphate: in uremic patients, the distribution spaces, turnover rate of calcium, and accretion rate of bones are increased in comparison with the controls; the calcium infusion test in patients with renal osteomalacia is followed by a regular increase in plasma [PO4], whereas a significant decrease is observed in patients with renal osteitis fibrosa, due to the extreme 'avidity' of bones for calcium phosphate; the role of hyperphosphatemia is critical in keeping the plasma [Ca] lower than the expected values for a given metabolic set; moreover, an increased cell uptake of phosphate could counteract to some extent the reduced renal clearance of phosphate; (4) structural and biochemical modifications of bone tissue: uremic osteodystrophy consists mainly of two components: (a) osteomalacia, with osteoid excess, disappearance of the calcification front, and diffuse pathologic mineralization, and (b) osteitis fibrosa, with severe resorption of normally mineralized bone, slight osteoid excess, and almost normal calcification front; (5) hormonal factors: chronic stimulation of parathyroid glands may result in suppressible or even autonomous hyperparathyroidism. As to vitamin D, it has been suggested that the uremic kidney is not able to synthesize the 1,25-di-OH-cholecalciferol, the active metabolite of vitamin D: this results in an impaired intestinal absorption of calcium. On the contrary, the role of calcitonin in chronic uremia is still uncertain, since low values of plasma [Ca] are usually observed.
 ...
PMID:Calcium and phosphorus metabolism in chronic uremia. 109 55

The aetiology of senile osteoporosis was investigated in a series of elderly normal persons (mean age 76.8 years) who were compared to 18-19 year old normal controls. Osteoporosis was estimated by standard radiological morphometric and densitometric techniques, in the metacarpals and thoraco-lumbar vertebrae. Serum parathyroid hormone levels were significantly higher in the elderly group, and correlated well with morphometric and densometric measurements of osteoporosis. Creatinine clearance was reduced in seven out of nine of the elderly group, and correlated well with the degree of osteoporosis. Serum thyrocalcitonin levels were reduced in the elderly. Tubular reaborption of phosphate and TmP/GFR were in the hyperparathyroid range in the elderly group and correlated well with the degree of osteoporosis. The hypothesis is advanced that the osteoporosis of old age is a result of parathyroid overactivity, caused by asymptomatic chronic renal failure. The suggestion is made that a diet low in phosphorus might reduce the incidence of osteoporosis in old age by reducing the parathyroid overactivity.
 ...
PMID:The aetiology of senile osteoporosis: secondary hyperparathyroidism due to renal failure. 117 20

The effects of a very low-protein diet (VLPD) supplemented with amino acids and ketoanalogues (KA) and with 1 g of calcium carbonate and 1000 IU of vitamin D2, were studied in 17 patients with advanced renal failure (GFR < or = 20 ml/min) over a period of one year. The protein intake was 0.3 g protein/kg body wt/day. Daily phosphorus and calcium intake were respectively 1,500 mg and 300 mg. Sequential bone densitometry was performed and bone histomorphometry after double tetracycline labeling was evaluated, before and after one year of diet. Calcium and phosphate metabolism parameters were monitored every two months. In spite of a significant decrease of GFR, phosphorus, parathyroid hormone (1-84) and osteocalcin plasma levels decreased significantly, while low plasma bicarbonate normalized, and calcitriol and calcium levels remained respectively low and normal. Before the diet, histological study disclosed four cases of mixed osteopathy: osteomalacia associated with osteitis fibrosa (OM/OF), nine pure osteitis fibrosa (OF) and four with normal bone remodeling (NB). After one year of diet, the OM component of OM/OF disappeared, as evidenced by a normalization of the mineral apposition rate and osteoid thickness. In the patients presenting pure OF, a significant decrease in osteoblastic and osteoclastic surfaces, in the number of osteoclasts, and in the bone formation rate (BFR) were found. Vertebral mineral density measured by quantitative computerized tomodensitometry did not change significantly. In conclusion, this study not only confirms the beneficial effects of VLPD + KA + calcium on uremic hyperparathyroid bone disease in advanced renal failure assessed using static bone histomorphometry, but also shows a correction of histodynamic bone parameters.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Ketodiet, physiological calcium intake and native vitamin D improve renal osteodystrophy. 145 6

Inadequate low intake of phosphorus can induce a hypophosphatemic depletion syndrome resulting in hypercalcemia, hypercalciuria, hypophosphatemia, and rickets. Tubular reabsorption for phosphate per liter glomerular filtration rate (TP/GFR) has been proposed as a reliable index of renal phosphate handling for all age groups. In the present study, carried out in 12 healthy premature babies fed unmodified pooled human milk and then a preterm formula for two periods of 10 days, we demonstrated clearly that TP/GFR as well as calciuria can reflect the poor phosphorus intake and that the kidney of preterm babies is able to rapidly adapt itself to an increase in phosphorus diet content.
 ...
PMID:Phosphorus intake in preterm babies and variation of tubular reabsorption for phosphate per liter glomerular filtrate. 152 68

Renal tubular reabsorption of phosphate in response to GH administration was studied in 28 short Japanese children, aged 5-11 yr (height SD score, less than -2.0 SD). Three groups included a classical GH deficiency (group 1; n = 12), a partial GH deficiency (group 2; n = 7), and children with non-GH deficiency (group 3; n = 9), depending on the peak response of serum GH in four provocative tests. Serum phosphorus, alkaline phosphatase, insulin-like growth factor-I (IGF-I), osteocalcin, and ratio of the maximum tubular reabsorption rate for phosphorus to the glomerular filtration rate (Tmp/GFR) were all significantly lower in group 1 compared with findings in groups 2 and 3 (P less than 0.05, P less than 0.01, and P less than 0.001). After the administration of GH (0.1 U/kg.day) for 4 consecutive days, increments in serum phosphorus and Tmp/GFR were significantly higher in group 1 than in group 2 (P less than 0.01 and P less than 0.01) or group 3 (P less than 0.01 and P less than 0.01), whereas the increment in IGF-I was similar in all 3 groups, and the levels of serum alkaline phosphatase and osteocalcin remained unchanged in all 3 groups. The calculated ratio of the increment in Tmp/GFR to the increment in IGF-I (delta Tmp/GFR/delta IGF-I) was highest in group 1, intermediate in group 2, and lowest in group 3 (P less than 0.001). One year after the GH treatment (0.5 U/kg.week), height velocity was 7.9 +/- 2.2 cm/yr in group 1 and 5.9 +/- 1.2 cm/yr in group 2; no child in group 3 was treated. When the above calculated parameters, delta Tmp/GFR/delta IGF-I and increment in height velocity (difference between pre- and posttherapy values), were taken into account, there was a significant positive correlation (n = 19; r = 0.78; P less than 0.001). This parameter can be used for purposes of predicting the outcome after 1 yr of GH therapy.
 ...
PMID:Renal handling of phosphate can predict height velocity during growth hormone therapy for short children. 154 58

Twelve patients with severe chronic renal failure (average initial GFR, 13 mL/min) were monitored for 4 to 23 months while receiving an essential amino acid supplement and were then switched to a ketoacid supplement for 6 to 40 months, while continuously receiving a very low-protein (0.3 g/kg), low-phosphorus (7 to 9 mg/kg) diet. Urinary urea N excretion indicated that actual dietary protein intake averaged 0.46 g/kg. Progression, estimated as the linear regression slope of radioisotopically determined GFR on time, slowed from -0.46 +/- 0.31 (SD) to -0.24 +/- 0.15 mL/min/month (P = 0.029). Serum urea N, creatinine, phosphate, and uric acid rose significantly as GFR fell; blood pressure, plasma lipids, and urinary urea excretion were unchanged. Urinary 17-hydroxy-corticosteroid excretion decreased 18%, but this change was only marginally significant (P = 0.087). There was no change in plasma or urinary cortisol or urinary aldosterone. Viewed in light of previous evidence that progression seldom slows when treatment remains constant, the results suggest that this ketoacid supplement slows progression by approximately half, compared with an essential amino acid supplement, with no change in diet.
 ...
PMID:Progression of chronic renal failure on substituting a ketoacid supplement for an amino acid supplement. 159 58

The Modification of Diet in Renal Disease (MDRD) Study is a multicenter clinical trial designed to assess acceptance, safety, and efficacy of restricted protein and phosphorus diets in patients with progressive renal disease. The Feasibility Study was designed to test procedures and recruitment strategies and to estimate sample size for the Full-Scale Trial. The Feasibility Study was not designed to compare rates of progression of renal disease among diet groups. Patients aged 18 to 75 years, with a glomerular filtration rate (GFR; measured by 125I-iothalamate clearance) between 7.5 and 80 mL/min/1.73 m2, and a previous progressive increase in serum creatinine, were eligible for enrollment. Compliance with prescribed dietary protein intake was calculated from urea nitrogen appearance (UNA). Nutritional status was monitored by anthropometry and serum proteins. Progression of renal disease was calculated as the rate of decline of GFR. Ninety-six patients met all of the eligibility requirements and were randomized to study diets. Follow-up was conducted for a mean duration of 14 months (range, 2 to 22 months). Although most patients did not achieve the prescribed protein intake, marked changes in intake were observed among patients assigned to the low-protein diets, and mean estimated protein intake differed significantly among diet groups. No patients became malnourished. Mean rates of decline in GFR were relatively slow, and variability among individuals was high. As expected, the number of patients enrolled was too small to determine if the rate of decline in GFR was significantly slower among patients assigned to the restricted protein and phosphorus diets. The rate of decline in GFR was significantly inversely correlated with long-term average mean arterial blood pressure (MAP), even among patients whose blood pressure was controlled to levels within the normal range. However, because patients were not randomly assigned blood pressure goals, it was not possible to determine whether a causal relationship exists. Based on the experience gained during the Feasibility Study, the design for the Full-Scale Study includes two studies of defined by patients' baseline levels of renal function. Within each study, patients will be assigned randomly to one of two diets, and within each diet group, to one of two levels of blood pressure control. Based on variability of rates of decline in GFR slopes observed during the Feasibility Study, 800 patients with follow-up periods of up to 4 years will be required for the Full-Scale Trial.
 ...
PMID:The Modification of Diet in Renal Disease Study: design, methods, and results from the feasibility study. 162 75


1 2 3 4 5 6 7 8 9 10 Next >>