Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent evidence indicates that cAMP-mediated responses are desensitized in liver during malnutrition. While receptor-stimulated production of cAMP is increased in hepatocytes from rats fed very low protein diets for 14 d, activity of cAMP-dependent protein kinase (PKA) is decreased in liver cytosol. The present study investigated the time course for this desensitization. Weanling rats were fed either a 0.5 (malnourished) or 15% protein (control) diet for 1, 3, 7 or 14 d. Total PKA activity decreased after only 3 d of feeding the low protein diet. This decrease was confined to the cytosolic compartment and was associated with a lower quantity of immunoreactive RI regulatory subunit of PKA, with no difference in the quantity of immunoreactive RII regulatory subunit. In contrast, basal-, MnCl2- and guanine nucleotide regulatory protein-stimulated adenylyl cyclase activities were not greater in liver membranes of malnourished rats than in those of the control rats until the 2nd wk of feeding. Greater activity was paralleled by an increase in the quantity of the stimulatory guanine nucleotide regulatory protein at d 14. The inhibitory guanine nucleotide regulatory protein quantity did not differ between dietary groups. Greater cAMP production was not mediated by changes in PKA phosphorylation of adenylyl cyclase because preincubation of membranes with purified PKA catalytic subunit decreased MnCl2-stimulated cAMP production equally in liver membranes of both control and malnourished rats. Similarly, treatment with alkaline phosphatase decreased adenylyl cyclase activity but did not eliminate the difference in adenylyl cyclase activity between control and malnourished rats. These data demonstrate that loss of PKA activity is an early response to a low protein diet and that, subsequently, a number of molecular adaptations occur which increase cAMP production. These changes may be adaptive responses to malnutrition that maintain essential cAMP-dependent functions.
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PMID:Very low protein diets induce a rapid decrease in hepatic cAMP-dependent protein kinase followed by a lower increase in adenylyl cyclase activity in rats. 868 41

We have previously shown that elderly women with an increased serum undercarboxylated osteocalcin (ucOC) level have an increased risk of sustaining a hip fracture as compared to those with normal serum ucOC. We reassessed our findings on a larger number of hip fractures that occurred over 3 years in 183 institutionalized women (aged 70-97 years) belonging to a large prospective clinical trial. Total OC, carboxylated OC, ucOC, and alkaline phosphatase were significantly higher at baseline in those who sustained a hip fracture during the follow-up. The age-adjusted odds ratio for hip fracture was three times higher in women with increased ucOC at baseline (odds ratio = 3.1, 99.9% C.I. = 1.7-6.0, p < 0.001). In the logistic regression, ucOC was still predictive of the hip fracture when age and parathyroid hormone concentration were included into the model (odds ratio = 2.6, 95% C.I. = 1.05-6.4). These data confirm that ucOC is a marker of the increased risk of hip fracture in elderly institutionalized women. Serum ucOC may reflect some nutritional deficiency associated with increased bone fragility.
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PMID:Serum undercarboxylated osteocalcin is a marker of the risk of hip fracture: a three year follow-up study. 892 58

We evaluated the radiological, biochemical and growth hormone (GH)/insulin-like growth factor-I (IGF-I) changes in 10 children with severe protein-energy malnutrition (PEM) who had rachitic manifestations (group 1), 10 children with severe PEM without clinical signs of rickets (group 2), and 10 children with normal body weight-for-length and -age, suffering from vitamin-D-deficiency with signs of florid rickets (group 3) and 10 normal age-matched children (group 4). Serum calcium (Ca2+), phosphorus (PO4), and albumin concentrations were markedly decreased in the two groups with PEM. Malnourished children with rickets had significantly higher serum alkaline phosphatase (ALP) concentrations compared to the malnourished group without rachitic manifestations. Radiological evaluation of the two groups who had rachitic manifestations revealed demineralization of long bones, thinning of the bony cortex, increased formation of osteoid tissue, and metaphyseal changes including cupping, fraying, and flaring. The incidence of these radiological findings did not differ among the well-nourished and the malnourished groups with clinical signs of rickets. However, the incidence of fracture of the shaft was higher (40 per cent) in the malnourished group compared to the well-nourished group (10 per cent) with rickets. In the malnourished group without clinical evidence of rickets, demineralization and cortical thinning was detected in 40 per cent without significant metaphyseal changes. Basal concentrations of GH and peak GH response to clonidine were significantly elevated and IGF-I concentrations were significantly depressed in the malnourished groups v. the other two groups. There were no significant differences in the fasting and the clonidine provoked GH levels or IGF-I concentrations between the rachitic children (group 3) and the normal children. These data suggest that in rachitic children there is not a major role for circulating GH (and by implication IGF-I) on bone mineralization. However, during malnutrition decreased IGF-I production can slow or stop epiphyseal growth and might contribute to the demineralization of the cortex of long bones.
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PMID:Radiological, biochemical, and hormonal changes in malnourished children with rachitic manifestations. 882 Jun 18

Large tendon rupture is a rare catastrophic occurrence in dialysis patients. Pathogenesis of this has been variably thought to be due to malnutrition, insufficient dialysis, amyloidosis, chronic acidosis, or hyperparathyroidism. We investigated contributory causes and timing of this complication in 44 dialysis patients (42 hemodialysis and two peritoneal dialysis patients). Five cases were our own; the other 39 were reported in the literature during the last two decades. Data were compared with a hospital database of 916 patients. The patients who experienced tendon ruptures had been on dialysis longer (mean duration, 7.6 years v 4.0 years; P = 0.001), were younger (mean age, 39.7 years v 48.4 years; P = 0.0001), had much higher parathyroid hormone levels (1,802 pg/mL v 202 pg/mL; P = 0.0001), had a higher phosphate level (6.8 mg/dL v 5.9 mg/dL; P = 0.001), had a slightly higher calcium level (9.2 mg/dL v 8.8 mg/dL; P = 0.038), and had a higher alkaline phosphatase level (649 IU/L v 109 IU/L; P = 0.0001) than control patients. Patients with tendon ruptures had no evidence of malnutrition (albumin 3.7 g/dL v 3.8 g/dL; P = 0.237) and had the same acidosis (bicarbonate 22.2 mEq/L v 22.0 mEq/L; P = 0.180). The time on dialysis to rupture was inversely related to the patient's age (r = 0.47, P = 0.004). Most patients had evidence of years of poorly controlled hyperparathyroidism with high and increasing levels of parathyroid hormone and alkaline phosphatase. Previous steroid use was also much more common in patients with tendon ruptures, as was radiographic evidence of osteitis fibrosa. The disease led to long hospitalization and prolonged morbidity, with mobility limitations in several patients. Spontaneous large tendon rupture in patients is secondary to hyperparathyroidism; is more common in young patients, particularly if exposed to corticosteroids; leads to long-lasting morbidity; and should be preventable by better supervision and treatment of hyperparathyroidism.
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PMID:Spontaneous tendon ruptures in patients on chronic dialysis. 918 88

Infectious diarrheal diseases and protein-energy malnutrition (PEM) are major causes of child morbidity and mortality worldwide. In the present study, PEM was superimposed on rotavirus infection in neonatal pigs to simulate chronic small intestinal stress in malnourished infants with viral gastroenteritis. Two-day-old cesarean-derived pigs (n = 39) were allotted to three treatment groups: 1) noninfected, full-fed; 2) infected, full-fed; and 3) infected, malnourished. Two days postinfection, severe diarrhea and weight loss (11%) were accompanied by reductions in villus height (60%) and lactase activity (78%) and increased crypt depth (32%) in infected full-fed compared with noninfected pigs (P < 0.05). Malnutrition blunted (P < 0.05) increases in crypt depth elicited by rotavirus. By 9 d postinfection, body weight was 59% less, villus height and lactase activity remained lower (50%), and crypt depth remained greater (62%) in infected full-fed compared with noninfected pigs (P < 0.05). However, diarrhea began to clear in infected full-fed, but not in infected malnourished pigs. Plasma insulin-like growth factor-I (IGF-I) was reduced 68% and crypt depth was reduced 19% in infected-malnourished compared with infected full-fed pigs (P < 0.05). Sixteen days postinfection, full-fed pigs had recovered from rotaviral infection; however, in infected-malnourished pigs, diarrhea and growth stasis persisted, and plasma IGF-I, villus height and alkaline phosphatase activity remained reduced compared with infected full-fed pigs (P < 0.05). Overall, PEM prolonged diarrhea and delayed small-intestinal recovery, indicating that nutritional status during diarrhea is essential for recovery from rotaviral enteritis.
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PMID:Protein-energy malnutrition delays small-intestinal recovery in neonatal pigs infected with rotavirus. 918 26

The present study was carried out to find the effects of Pb acetate (10-50 mg/kg body wt) after oral administration on: 1. The distribution of elements, such as Fe, Cu, Zn, and Mn; 2. The activity of 6-amino levulenic acid dehydratase (delta-ALAD) and alkaline phosphatase (PAP); and 3. On the level of reduced glutathione (GSH) in murine placenta. Pb toxicity expressed on a dry-wt basis was reflected in terms of deficiency of delta-ALAD and PAP and enhanced content of GSH. Analysis of trace elements following Pb exposure showed low levels of Mn and Cu. Although Fe composition of placenta remained within normal range with increasing load of endogeneous Pb, Zn decline was not consistent after oral feeding of Pb acetate. Deficiency of PAP after Pb exposure did not correlate with the endogeneous levels of Pb or Zn therein, but correlated with endogeneous levels of Mn. Placental deficiencies of Cu and Mn have been related to the disturbed placental functions by Pb accumulation.
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PMID:Trace metals and metalloenzymes in placenta after oral administration of lead acetate. 940 84

The goal of this study was to evaluate the influence of severe protein-energy malnutrition (PEM) on lipid composition and fatty acid profile in the small intestinal mucosa of lactating pigs. Malnutrition was achieved by 80% protein-energy restriction for 30 d (20% of the food intake in the control group) in 7-d-old newborn piglets. Malnourished piglets had significantly lower concentrations of cholesterol, phospholipid and triglycerides in the jejunum and ileum compared with freely fed controls. Fatty acid composition of the intestinal mucosa was severely affected by malnutrition. A sharp decline in the relative percentages of (n-3) and (n-6) long-chain polyunsaturated fatty acids (LC-PUFA) in malnourished piglets paralleled higher (n-9) fatty acid proportions in the total mucosa, microsomes and phospholipids of the jejunum. The structure of the small intestine was severely affected as assessed by light and electron microscopy, and alkaline phosphatase and disaccharidase activities in the intestinal mucosa were also significantly impaired. Plasma from malnourished piglets had significantly lower concentrations of (n-3) and (n-6) LC-PUFA than that of control piglets; however, the fatty acid composition of red blood cell membrane was unaffected. Our results suggest that early severe PEM dramatically modifies intestinal membrane lipid composition. Changes in the lipid composition of the small intestinal mucosa and in phospholipid distribution as well as in the fatty acid profile may alter membrane fluidity and organization. These alterations appear to affect the activity of membrane-bound hydrolytic enzymes.
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PMID:Severe malnutrition alters lipid composition and fatty acid profile of small intestine in newborn piglets. 944 48

Long-chain polyunsaturated fatty acids are important for the growth and early development of the central nervous system. Cholestatic infants suffer from fat malabsorption and disturbed lipid metabolism and therefore may be at risk of developing polyunsaturated fatty acid depletion. The aims of this study were to determine essential fatty acid status in cholestatic infants and to study the relationship to disease severity, degree of undernutrition, antioxidant status and mode of feeding. Twenty-four-hour dietary records were obtained in 34 cholestatic infants, and measurements were taken of skin fold thicknesses, bilirubin levels, activities of serum alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase, prothrombin time, serum concentrations of albumin, bile acids, total lipids, phospholipids, cholesterol, vitamins A and E, the fatty acid composition of plasma phospholipids and plasma lipid peroxides expressed as thiobarbiturate reactive substance (TBARS). Plasma phospholipid fatty acids and TBARS were also determined in 12 age-matched healthy control infants. The cholestatic patients had very low percentage values of phospholipid essential fatty acids, particularly linoleic acid ( 18:2omega-6, median 14.74% vs 20.76% in controls, p < 0.001) and its major metabolite arachidonic acid (20:4omega-6, 6.80 vs 7.87%, p=0.04). The patients' essential fatty acid depletion was reflected by increased levels of the non-essential fatty acids, Mead acid (20:3omega-9, 0.74 vs 0.21%, p < 0.001) and palmitoleic acid (16:1omega-7, 2.20 vs 0.43%, p < 0.001). Polyunsaturated fatty acid profiles did not differ between infants with biliary atresia (n=13) and those with intrahepatic cholestasis (n=21), or between 17 infants with severe malnutrition (all skin folds < 10th percentile) and mild malnutrition (at least two skin folds > 10th percentile). TBARS were significantly higher in cholestatic patients than in controls (2.74 vs 0.85 nmol ml(-1), p < 0.001) and correlated with direct (r=0.41, p=0.02) and total bilirubin. The daily dietary intake of linoleic acid (per 100 kcal) correlated with plasma phospholipid linoleic acid (r=0.38,p=0.037) and total omega-6 fatty acids (r=0.38,p=0.036). Breastfed cholestatic infants (n=6) had higher values of the omega-3 long-chain polyunsaturated fatty acids docosapentanoic acid (22:5omega-3, 0.47 vs 0.28%, p=0.0006) and docosahexanoic acid (22:6omega-3, 2.39 vs 1.73%, p=0.01) than formula-fed infants, while disease severity was similar in the two groups. In conclusion, cholestatic infants are at high risk of essential fatty acid depletion, which appears to be related to fat malabsorption, hepatic essential fatty metabolism, enhanced lipid peroxidation and dietary intake.
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PMID:Essential fatty acid metabolism in infants with cholestasis. 956 34

The main purpose of our study was to verify the effect of a very-low-protein, low-phosphorus diet, supplemented with essential amino acids and keto analogues and with calcium carbonate, on circulating levels of intact parathyroid hormone (i-PTH) in severe chronic renal failure patients with secondary hyperparathyroidism, not treated with any vitamin D preparation. To this aim, we shifted 21 chronic uremics (12 males, 9 females; age 56 +/- 13 years) with serum creatinine >6.5 mg/dl and i-PTH >150 pg/ml, from a standard low-protein diet (0.6 g/kg/day approximately) to a very-low-protein (0.3 g/kg/day), very-low-phosphorus (5 mg/kg/day) diet supplemented with a mixture of essential amino acids and calcium keto analogues (Ketodiet), calcium carbonate (2-4 g/day), iron, and vitamin B12 preparations. The energy supply of both diets was 30-35 kcal/kg/day. Exclusion criteria were a poor compliance with dietary or supplement prescriptions or signs of autonomic hyperparathyroidism. After 4 +/- 2 months of Ketodiet, the i-PTH serum levels decreased by 49% as a mean (from 441 +/- 233 to 225 +/- 161 pg/ml, p < 0.001); serum phosphorus and alkaline phosphatase decreased, whereas serum calcium increased. The great reduction of serum and urinary urea demonstrated a good compliance with Ketodiet, and no sign of protein malnutrition was observed. These findings confirm that even in severe chronic uremic patients dietary phosphorus restriction and calcium carbonate supplementation lower i-PTH serum levels. This is one of the goals of the dietary treatment that can be safely achieved, provided good compliance both with the dietary prescriptions and with adequate energy and supplement intakes.
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PMID:Secondary hyperparathyroidism in severe chronic renal failure is corrected by very-low dietary phosphate intake and calcium carbonate supplementation. 964 91

Protein-energy malnutrition, which is common in elderly patients with osteoporotic hip fractures, is associated with reduced plasma levels of insulin-like growth factor-I (IGF-I). IGF-I is an important regulator of bone metabolism, particularly of osteoblastic bone formation both in vivo and in vitro. Pharmacological doses of arginine (Arg) increase growth hormone (GH) and IGF-I serum levels. Whether amino acids, particularly Arg, can directly modulate the production of IGF-I by osteoblasts is not known. We investigated the effects of increasing concentrations of Arg on IGF-I expression and production, alpha1(I) collagen expression and collagen synthesis, and cell proliferation and cell differentiation, as assessed by alkaline phosphatase (ALP) activity and osteocalcin (OC) release, in confluent mouse osteoblast-like MC3T3-E1 cells. The addition of Arg (7.5-7500 micromol/L, equivalent to 0.1- to 100-fold human plasma concentration) for 48 h increased IGF-I production (adjusted for cell number) in a concentration-dependent manner with a maximum of 2.3 +/- 0.3-fold at 7500 micromol/L Arg [x +/- standard error of the mean (SEM), n = 3 experiments, p < 0.01]. Arg (7.5-7500 micromol/L) increased the percentage of de novo collagen synthesis in a concentration-dependent manner (2.1 +/- 0.4-fold with 7500 micromol/L Arg, p < 0.001) and ALP activity with a maximal stimulation of 144% +/- 13% plateauing at 750 micromol/l Arg (p = 0.002). The steady state level of IGF-I messenger ribonucleic acid (mRNA) and alpha1(I) collagen mRNA (both normalized to cyclophilin mRNA) of cells incubated with Arg at high (100-fold) or low (0.1-fold) human plasma concentrations, was 1.4 +/- 0.2, 1.2 +/- 0.2, and 1.1 +/- 0.2 after 24 h for the 7.5, 1.8, and 0.9 kb IGF-I mRNA transcripts, respectively (n = 3 experiments) and 1.5 +/- 0.2 and 3.1 +/- 0.7 after 24 and 48 h, respectively, for the combined analysis of the 5.6 and 4.7 kb alpha1(I) collagen mRNA transcripts (n = 3 experiments). A maximal mitogenic effect (cell number) of +21% +/- 3% (p < 0.01) was obtained with 1000 micromol/L Arg. In contrast, Arg (7.5-7500 micromol/L) induced a reduction of OC production, which reached 30% +/- 3% with 7500 micromol/L Arg (p = 0.02). In conclusion, Arg stimulated IGF-I production and collagen synthesis in osteoblast-like cells. Thus, Arg may influence bone formation by enhancing local IGF-I production.
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PMID:Arginine increases insulin-like growth factor-I production and collagen synthesis in osteoblast-like cells. 970 68


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