Br J Nutr. "Citation Classic": Improvement of phosphorus availability by microbial phytase in broilers and pigs. Br J Nutr. 1990 Sep.
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6-Phytase↗
Biomedical subjects
P C Simons
Publications and source records attributed to P C Simons.
[Prevalence and treatment of hypercholesterolemia in patients with manifest vascular disease according to practice guidelines of the current cholesterol consensus].
OBJECTIVE: To determine the prevalence of hypercholesterolaemia and the use of lipid-lowering medication in patients with a manifest vascular disease. DESIGN: Prospective, cross-sectional. METHODS: In patients who visited the University Medical Centre Utrecht, the Netherlands, for the first time with a manifestation of atherosclerosis in the period 1 September 1996-15 November 1998, we determined by a single measurement of the cholesterol if they were eligible for lipid-lowering medication according to the cholesterol cut-off value mentioned in the new Dutch cholesterol guidelines (1998) of the Dutch Institute for Health Care Improvement. RESULTS: The study group comprised 737 patients: 539 (73%) males and 198 (27%) females, with a mean age of 62 year. 500 (68%) were eligible for lipid-lowering treatment. 66 patients (9%) were being treated according to the guidelines and in 106 (14%) the aim of a cholesterol lower than 5.0 mmol/1 was not reached despite cholesterol lowering medication. In 328 patients (45%) hyperlipidaemia was not treated pharmacologically. CONCLUSION: Two-thirds of the patients with manifest vascular disease had hypercholesterolaemia. Many of these patients were not yet being treated.
Aged↗
Effects of ambient temperature, arginine-to-lysine ratio, and electrolyte balance on performance, carcass, and blood parameters in commercial male turkeys.
The effects of ambient temperature (T; 15 C vs. 30 C from 6 wk of age onwards), dietary Arg:Lys ratio (Arg:Lys ratio; 1.00 vs. 1.25), dietary electrolyte balance (DEB: 164 vs. 254 meq/kg), and their interactions on growth performance and carcass yields of male turkeys were studied. The experiment was designed as a split plot, including T x DEB as the main plot and Arg:Lys ratio as the sub-plot, with 24 pens containing 35 male turkeys each. Feed consumption, BW gain, mortality, and processing yields were measured. Temperature had a clear effect on performance during all age periods. Feed intake was significantly lower for the high T group compared with the low T group (322.7 vs. 432.3 g/bird per day; P < 0.001). Consequently, BW gain during the experimental period (28 to 140 d of age) was significantly lower for the high T group compared with the low T group (14.54 vs. 18.74 kg; P < 0.001). Feed:gain during the period of 28 to 140 d of age was significantly lower for the high T group compared with the low T group (2.51 vs. 2.61; P < 0.001). The high dietary Arg:Lys ratio increased feed intake significantly until 56 d of age (200.6 vs. 197.6; P < or = 0.034). A high Arg:Lys ratio resulted in significantly higher BW gain until 98 d of age (10.03 vs. 9.84 kg; P < or = 0.024). The Arg:Lys ratio did not affect feed:gain throughout the experiment. Dietary electrolyte balance did not affect performance parameters. No consistent two- or three-way interactions were observed. Processing yields were only affected significantly by T, and not by Arg:Lys ratio or DEB main effects. High T resulted in lower cold carcass (73.2 vs. 74.9%) and breast meat yields (33.5 vs. 36.0%), and higher thigh (18.9 vs. 18.1%), drumstick (14.5 vs. 13.2%), and wing yields (11.7 vs. 10.6%) compared with low T. We concluded that growth performance is compromised by higher T, and altering the Arg:Lys ratio or DEB does not alleviate this impaired performance. Dietary Arg levels seem to be important when dietary Lys is marginal relative to the requirement.
Animal Feed↗
Common carotid intima-media thickness and arterial stiffness: indicators of cardiovascular risk in high-risk patients. The SMART Study (Second Manifestations of ARTerial disease).
BACKGROUND: Common carotid intima-media thickness (IMT) and distensibility are markers of structural and functional vessel wall properties. Both parameters have been found in population-based studies to be associated with cardiovascular risk factors and prevalent cardiovascular disease. We investigated cross-sectionally whether IMT and distensibility are associated with cardiovascular risk in patients who already have vascular disease or atherosclerotic risk factors and evaluated the diagnostic ability of IMT and distensibility to discriminate between low- and high-risk patients. METHODS AND RESULTS: IMT and distensibility (change of diameter) of the left and right common carotid arteries were measured in the first 570 patients (537 for distensibility) enrolled in the Second Manifestations of ARTerial disease (SMART) study, a cohort study among patients with a manifestation of vascular disease or cardiovascular risk factors. Three risk scores were used to classify each patient's vascular risk. Areas under the curve (AUCs) of receiver-operating characteristic curves were calculated for IMT and distensibility after the patients were dichotomized on the median of the risk scores as the outcome. Risk scores increased nearly linearly with increasing IMT and decreasing distensibility. The AUCs for IMT predicting high-risk patients were 0.77, 0.73, and 0.77 based on the 3 risk scores. The AUCs for distensibility were 0. 65, 0.62, and 0.66. CONCLUSIONS: Common carotid IMT and distensibility are clear markers of cardiovascular risk in patients who already have vascular disease or atherosclerotic risk factors. IMT appears to discriminate between low- and high-risk patients better than distensibility.
Adult↗
Common carotid intima-media thickness in patients with peripheral arterial disease or abdominal aortic aneurysm: the SMART study. Second Manifestations of ARTerial disease.
Evidence is emerging that the contribution of atherosclerosis to the development of abdominal aortic aneurysm may differ from that of other manifestations of arterial disease. B-mode ultrasound may be helpful in understanding the characteristics and factors that contribute to the development of different manifestations of arterial disease. We examined whether there is a difference in common carotid intima-media thickness (IMT), an indicator of generalized atherosclerosis, in patients with peripheral arterial disease (PAD) and abdominal aortic aneurysm (AAA). IMT of the left and right common carotid artery was measured in the first 172 patients (123 PAD and 49 AAA) enrolled in the Second Manifestations of ARTerial disease (SMART) study, a cohort study among patients with a manifestation of atherosclerotic vascular disease or risk factors for atherosclerosis. Mean IMT was 0.98 +/- 0.34 mm in patients with PAD and 0.91 +/- 0.20 mm in patients with AAA, with an age and sex adjusted mean difference of 0.18 mm (95% CI 0.08; 0.28). After additional adjustments for cardiovascular risk factors, the difference remained 0.11 mm (95% Cl 0.01; 0.21). Common carotid IMT in patients with AAA is on average smaller than in patients with PAD, independent of other determinants of IMT. These findings support the view that the development of AAA cannot completely be explained by atherosclerosis and is in part due to other pathophysiological mechanisms.
Aged↗
Carotid artery stenosis in patients with peripheral arterial disease: the SMART study. SMART study group.
PURPOSE: The prevalence of asymptomatic internal carotid artery stenosis (ICAS) in patients with peripheral arterial disease (PAD) and characteristics that are associated with ICAS were studied. METHODS: We used data from the first 600 patients enrolled in the Second Manifestations of ARTerial disease (SMART) study, a single-center, prospective cohort study among patients referred with a manifestation of cardiovascular disease, diabetes mellitus, hypertension, or hyperlipidemia. Included in the analysis were 162 patients with PAD or a history of PAD, who were not known to have ICAS at the time of referral and who had no history of cerebrovascular symptoms or previous carotid endarterectomy. ICAS was detected with duplex scanning and defined as a peak systolic velocity more than 150 cm/s (diameter reduction 50% or higher) on at least one side. Cardiovascular risk factors were measured. Logistic regression analysis was performed to investigate associations between these characteristics and ICAS. RESULTS: The prevalence of previously unknown ICAS was 14%. A patient age of 67 years or older, body weight of 68 kg or less, and diastolic blood pressure of 75 mm Hg or lower were independently associated with ICAS. The Prevalence Of Icas In Patients With One Of These Characteristics (38% Of The Patients) Was 8%, In Those With Two Characteristics (21% Of The Patients) Was 32%, And In Those With Three Characteristics (6% Of The Patients) Was 50%. CONCLUSIONS: The prevalence of ICAS increases as much as 50% in patients who have PAD and the risk indicators of an age of 67 years or older, a body weight of 68 kg or less, and a diastolic blood pressure of 75 mm Hg or lower, and, therefore, these characteristics may be used as a means of increasing the likelihood of detecting ICAS.
Age Factors↗
Second manifestations of ARTerial disease (SMART) study: rationale and design.
The Second Manifestations of ARTerial disease (SMART) study is a single-centre prospective cohort study among patients, newly referred to the hospital with (1) clinically manifest atherosclerotic vessel disease, or (2) marked risk factors for atherosclerosis. The first objectives of the SMART study are to determine the prevalence of concomitant arterial disease at other sites, and risk factors in patients presenting with a manifestation of arterial disease or vascular risk factor and to study the incidence of future cardiovascular events and its predictors in these high-risk patients. At least 1000 patients, aged 18 to 80 years, will undergo baseline examinations, including a questionnaire on cardiovascular disease, height, weight and blood pressure measurements, blood tests for glucose, lipids, creatinine and homocysteine, urinary tests for microproteinuria, resting twelve-lead electrocardiogram, ultrasound scanning of the abdominal aorta, kidneys and the carotid arteries, measurements of common carotid intima-media thickness and arterial stiffness, and a treadmill test to assess atherosclerosis of the leg arteries. Abnormal findings are reported to the treating specialist and general practitioner with a treatment suggestion according to current practice guidelines. Recruitment and baseline examinations began in September 1996. All cohort members will be followed for clinical cardiovascular events for a minimum of three years. In the scope of secondary prevention, the study is expected to support the design of solid based screening and treatment programmes and evidence-based cardiovascular medicine to reduce morbidity and mortality, and improve quality of life, in high-risk patients.
Adolescent↗
C-terminal threonine phosphorylation activates ERM proteins to link the cell's cortical lipid bilayer to the cytoskeleton.
The plasma membrane consists of a lipid bilayer with integral membrane proteins stabilized by regulated linkages to the cortical actin cytoskeleton. The regulation is necessary for cells to change shape ormigrate. The ERM (ezrin-radixin-moesin) proteins are believed to provide such links, with the N-terminal halves associating with integral membrane proteins, either directly or indirectly through adapter molecules like EBP50 (ERM binding phosphoprotein, 50 kDa), and their C-terminal halves associating with F-actin. However, isolated ERM proteins largely exist in a dormant state by virtue of an intramolecular interaction between amino- and carboxyl-terminal domains, thereby masking membrane and cytoskeletal association sites. C-terminal threonine phosphorylation of a fragment of radixin has been found to destroy its ability to bind the amino-terminal domain without affecting the C-terminal F-actin binding site. Here we show that C-terminal phosphorylation of full-length, dormant ezrin and moesin by protein kinase C-theta simultaneously unmasks both the F-actin and EBP50 binding sites. Increased phosphorylation of moesin in cells correlated with increased association of moesin with the cortical actin cytoskeleton. These results show that activation of ERM proteins can be accomplished by phosphorylation of a single C-terminal threonine residue.
Actins↗
[The screening for asymptomatic vascular disease and risk factors in high risk patients: current practice].
OBJECTIVE: To assess current practice in screening for asymptomatic vascular disease and risk factors in patients referred with vascular disease or cardiovascular risk factors. DESIGN: Descriptive, retrospective. SETTING: University Hospital Utrecht, Utrecht, the Netherlands. METHOD: By means of the computerized hospital registration system all patients who were referred to the outpatient clinic with carotid stenosis, peripheral artery disease, abdominal aortic aneurysm, diabetes mellitus, hyperlipidaemia or hypertension during one year were identified. By means of the same hospital registration system the frequency of diagnostic tests performed to detect atherosclerosis or risk factors in these patients within a period of 5 months round the first attendance was determined. RESULTS: 372 Patients with a vascular disease and 317 patients with a risk factor were identified. Tests to detect carotid stenosis, peripheral artery disease or an abdominal aortic aneurysm were each performed in less then 6% of all patients except the test for abdominal aortic aneurysm. Tests to detect coronary artery disease were performed in about 50% of all patients. Tests to detect diabetes mellitus were performed in 35% of the patients with vascular disease and in 81% of the patients presenting with hyperlipidaemia or hypertension. Tests to detect hyperlipidaemia were performed in 18% of the patients with a vascular disease and in 76% of the patients with diabetes or hypertension. CONCLUSION: The results of this study suggest that in current practice patients referred for vascular disease or cardiovascular risk factors are infrequently screened for asymptomatic macrovascular disease and risk factors.
Adult↗
Protein kinase C-theta phosphorylation of moesin in the actin-binding sequence.
Moesin, a member of the ezrin-radixin-moesin (ERM) family of membrane/cytoskeletal linkage proteins, is known to be threonine-phosphorylated at Thr558 in activated platelets within its conserved putative actin-binding domain. The pathway leading to this phosphorylation step and its control have not been previously elucidated. We have detected and characterized reactions leading to moesin phosphorylation in human leukocyte extracts. In vitro phosphorylation of endogenous moesin, which was identified by peptide microsequencing, was dependent on phosphatidylglycerol (PG) or to a lesser extent, phosphatidylinositol (PI), but not phosphatidylserine (PS) and diacylglycerol (DAG). Analysis of charge shifts, phosphoamino acid analysis, and stoichiometry was consistent with a single phosphorylation site. By using mass spectroscopy and direct microsequencing of CNBr fragments of phospho-moesin, the phosphorylation site was identified as KYKT*LRQIR (where * indicates the phosphorylation site) (Thr558), which is conserved in the ERM family. Recombinant moesin demonstrated similar in vitro phospholipid-dependent phosphorylation compared with the endogenous protein. The phosphorylation site sequence of moesin displays a high degree of conservation with the pseudosubstrate sequences of the protein kinase C (PKC) family. We identified the kinase activity as PKC-theta on the basis of immunodepletion of the moesin kinase activity and copurification of PKC-theta with the enzymic activity. We further demonstrate that PKC-theta displays a preference for PG vesicles over PI or PS/DAG, with minimal activation by DAG, as well as specificity for moesin compared with myelin basic protein, histone H1, or other cellular proteins. Expression of a human His6-tagged PKC-theta in Jurkat cells and purification by Ni2+ chelate chromatography yield an active enzyme that phosphorylates moesin. PG vesicle binding experiments with expressed PKC-theta and moesin demonstrate that both bind to vesicles independently of one another. Thus, PKC-theta is identified as a major kinase within cells with specificity for moesin and with activation under non-classical PKC conditions. It appears likely that this activity corresponds to a specific intracellular pathway controlling the function of moesin as well as other ERM proteins.
Actins↗
Effect of timing of blood pressure measurement in the assessment of arterial stiffness: the SMART Study.
In the assessment of arterial stiffness, pulse pressure is measured. Presently, there is no consensus on how pulse pressure should be measured. Distensibility of the left and right common carotid arteries was measured noninvasively in 224 patients participating in the Second Manifestations of ARTerial disease (SMART) study. Blood pressure was recorded every 4 min, using a semiautomatic oscillometric device. Distensibility coefficients (DC) were calculated with pulse pressure obtained as an average of (A) all measurements during the session; (B) the second, third, and fourth measurement; (C) measurements before and after distensibility assessment; and (D) three measurements nearest to distensibility assessment. Associations of cardiovascular risk factors with the four calculated DCs were evaluated with linear regression analysis. DC estimates were slightly more precise with methods A and B than with C or D. The magnitude of the associations showed a slight trend to higher precision for methods A and B. Pulse pressures obtained as an average of all or the second, third, and fourth blood pressure measurements during an arterial stiffness measurement session yield slightly more precise estimates of DC. However, the differences between the methods are small; therefore, we suggest that pragmatic arguments dominate the choice between the methods.
Blood Pressure Determination↗
The efficacy of phytase in corn-soybean meal-based diets for laying hens.
Microbial phytase hydrolyzes poorly degradable vegetable phytate P in the gastrointestinal tract of poultry; thereby increasing the availability of organic P to an extent that remains to be established. For this purpose, the P equivalency value of phytase in corn-soybean meal layer diets was assessed in three experiments (two short-term absorption studies and one performance trial lasting a complete production period). In the first absorption study, two basal diets containing 30 or 40 g Ca/kg diet were supplemented with either phytase [0, 250, or 500 phytase units (FTU)/kg diet] or with monocalcium phosphate (MCP; 0, 0.5, or 1.0 g P/kg diet) and fed to layers from 20 to 24 wk of age. The ileal absorption of Ca and P was measured during the last week. It was shown that 250 FTU/kg diet hydrolyzed an amount of phytate P that was equivalent to 1.3 g P from MCP. At the highest phytase inclusion level (500 FTU/ kg diet), a lower value of equivalency was observed, as P absorption was almost maximal at the lower level of phytase inclusion (250 FTU/kg diet). Phytase hydrolyzed phytate-bound P effectively at both Ca levels, although this degradation was significantly reduced by 12 percentage units at the higher dietary Ca level. The second absorption study, used 0, 250, and 500 FTU phytase/kg diet and 0 and 1.0 g P/kg diet of MCP. All diets were standardized at 35 g Ca/kg diet. The ileal absorption of Ca and P was determined at 24 and 36 wk of age. These values were significantly reduced in 36-wk-old hens compared to 24-wk-old hens. At 24 wk of age, phytic acid P degradation was significantly improved with increasing levels of phytase up to the maximum inclusion level of 500 FTU/kg diet (maximum phytic acid-P degradation at the end of the small intestine was 66%). In this experiment, the dose of 250 FTU/kg diet was equivalent to 0.8 g MCP-P. In Experiment 3, either phytase or MCP-P was added to a corn-soybean meal layer diet, containing 40 g Ca/kg diet and 3.6 g P/kg diet, at levels of 0, 100, 200, and 300 FTU/kg or levels of 0, 0.3, 0.6, and 0.9 g MCP-P/kg, respectively. Production performance was measured from 18 to 68 wk of age. Diets were consumed ad libitum. Growth, production performances (except kilograms of feed per kilogram of egg), and tibia parameters were significantly improved by dietary supplementation of the negative control diet with either phytase or MCP-P. Growth, egg production, and feed conversion ratio of the hens from the supplemented groups remained good throughout the experiment. No phytase dose effects on the production characteristics or tibia parameters were observed, indicating that the P requirements of the laying hens were met throughout the production period even at the lowest level of supplementation.
6-Phytase↗
The 47-kD fragment of talin is a substrate for protein kinase P.
This laboratory has been characterizing protein serine/threonine kinase reactions of hematopoietic tissues, whose most distinguishing characteristics in vitro are stimulation with vesicular phosphatidyl glycerol, and the ability to function using Mn2+ as the sole divalent cation. The major protein substrates are a 73-kD protein and a protein migrating near ovalbumin on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The 47-kD protein was partially purified from cells harvested by leukapheresis from a patient with acute myelogenous leukemia, using ammonium sulfate precipitation and ion exchange chromatography. This partially purified ion-exchange fraction contained an endogenous kinase activity with characteristics similar to those we previously described of protein kinase P (protein kinase, phospholipid-stimulable: PK-P), but not typical of any form of protein kinase C (PK-C). With longer phosphorylation, the 47-kD band showed increasingly lower mobility demonstrable both by Coomassie blue staining and autoradiography, suggesting both that it was multiply phosphorylated, and that the excisable band was pure. The protein was thus eluted from preparative gel slices and digested with endoproteinase lys C. Sequence data from the fragments identified the protein as the 47-kD calpain fragment of talin, a protein found in focal adhesion plaques and some cell-cell contacts. PK-C phosphorylated the 47-kD protein, as has been reported previously, and phosphopeptide mapping disclosed a similar pattern of phosphorylation using either PK-C or the endogenous activity. The 47-kD protein labeled with the endogenous kinase contained predominantly phosphoserine, with some phosphothreonine and a trace of phosphotyrosine. Intact, purified talin was also phosphorylated by PK-P in a phospholipid-stimulable manner, but at 1/20 the rate of the 47-kD fragment.
Amino Acid Sequence↗
Improvement of phosphorus availability by microbial phytase in broilers and pigs.
Techniques have been developed to produce microbial phytase for addition to diets for simple-stomached animals, with the aim to improve phosphorus availability from phytate-P in plant sources. The activity of the crude microbial phytase showed pH optima at pH 5.5 and 2.5. The enzyme was able to degrade phytate in vitro in soya-bean meal, maize and a liquid compound feed for pigs. When microbial phytase was added to low-P diets for broilers the availability of P increased to over 60% and the amount of P in the droppings decreased by 50%. The growth rate and feed conversion ratio on the low-P diets containing microbial phytase were comparable to or even better than those obtained on control diets. Addition of microbial phytase to diets for growing pigs increased the apparent absorbability of P by 24%. The amount of P in the faeces was 35% lower.
6-Phytase↗
cDNA cloning and predicted amino acid sequence of Glycera dibranchiata monomer hemoglobin IV.
The three major monomer hemoglobins from Glycera dibranchiata erythrocytes isolated in this laboratory were sequenced from their N-termini. A stretch of amino acid sequence identity was used to determine the sequence of a mixed oligodeoxynucleotide that would be complementary to all 12 possible mRNA sequences coding for the amino acids. A cDNA library was constructed by using poly(A+) RNA from G. dibranchiata erythrocytes, the library was probed with the oligonucleotide, and the longest positive inserts found were subcloned into a sequencing plasmid and then sequenced. The first one was 745 bases long, containing 85 bases of 5'-untranslated RNA, an open reading frame of 444 bases coding for 148 amino acids, and a 3'-untranslated region of 216 bases. The predicted amino acid sequence matches the first 25 amino acids of G. dibranchiata monomer globin component IV. The sequence contains an N-terminal methionine plus 18 other mostly conservative sequence changes compared to the published sequence of Imamura et al. (1972), which appears from our partial sequencing to be monomer globin component II. We confirm the presence of leucine in the E7 position, which is histidine in most myoglobins and hemoglobins.
Amino Acid Sequence↗
A stopped-flow mixer device for a batch microcalorimeter application to NAD-NADase reaction.
A new molded polypropylene, diamond-like carbon (DLC)-coated mixing cell has been developed for use in the batch microcalorimeter. Reagent volume can be varied from 25 microliters to 100 microliters. A 10 microcalorie reaction heat can be measured to 5%. Repeat reactions can be done as often as every 10 min for a fast reaction. Reactions can be started within 1 h or less after loading. A pre-equilibrator and a temperature-controlled syringe drive unit permit solutions to be stored at 4 degrees C while being run at any temperature from -20 degrees C to 40 degrees C. The kinetics and enthalpy of reaction of NAD-NADase have been measured. delta H is about 21 kcal/mol endothermic.
Calorimetry↗
Site-directed mutagenesis of yeast cytochrome c peroxidase shows histidine 181 is not required for oxidation of ferrocytochrome c.
The long-distance electron transfer observed in the complex formed between ferrocytochrome c and compound I, the peroxide-oxidized form of cytochrome c peroxidase (CCP), has been proposed to occur through the participation of His 181 of CCP and Phe 87 of yeast iso-1 cytochrome c [Poulos, T. L., & Kraut, J. (1980) J. Biol. Chem. 255, 10322-10330]. We have examined the role of His 181 of CCP in this process through characterization of a mutant CCP in which His 181 has been replaced by glycine through site-directed mutagenesis. Data from single-crystal X-ray diffraction studies, as well as the visible spectra of the mutant CCP and its 2-equiv oxidation product, compound I, show that at pH 6.0 the protein is not dramatically altered by the His 181----Gly mutation. The rate of peroxide-dependent oxidation of ferrocytochrome c by the mutant CCP is reduced only 2-fold relative to that of the parental CCP, under steady-state conditions. Transient kinetic measurements of the intracomplex electron transfer rate from ferrous cytochrome c to compound I indicate that the rate of electron transfer within the transiently formed complex at high ionic strength (mu = 114 mM, pH = 6) is also reduced by approximately 2-fold in the mutant CCP protein. The relatively minor effect of the loss of the imidazole side chain at position 181 on the kinetics of electron transfer in the CCP-cytochrome c complex precludes an obligatory participation of His 181 in electron transfer from ferrous cytochrome c to compound I.(ABSTRACT TRUNCATED AT 250 WORDS)
Cytochrome c Group↗
Bilirubin binding to rat liver ligandins (glutathione S-transferases A and B). Relationship between bilirubin binding and transferase activity.
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Animals↗