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| Title: [ Changes in mineral metabolism in stage 3 , 4 , and 5 chronic kidney disease ( not on dialysis ) ] | | Author: Lorenzo Sellares V Torregrosa V | | Journal: Nefrologia Citation: V : 28 Suppl 3 P : 67-78 Year: 2008 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19018742 Accession (PMID): 19018742 | | Abstract: With progression of chronic kidney disease ( CKD ) , disorders of mineral metabolism appear .
The classic sequence of events begins with a deficit of calcitriol synthesis and retention of phosphorus .
As a result of this , serum calcium decreases and parathyroid hormone ( PTH ) is stimulated , producing in the bone the high turnover ( HT ) bone disease known as osteitis fibrosa while on the other extreme we find the forms of low turnover ( LT ) bone disease .
Described later and initially associated with aluminum intoxication , these diseases are now seen primarily in older and/or diabetic patients , who in a uremic setting have relatively low levels of PTH to maintain normal bone turnover .
Osteomalacia is also included in this group , which after the disappearance of aluminum intoxication is rarely observed .
LT forms of hyperparathyroidism facilitate the exit of calcium ( Ca ) and phosphorus ( P ) from bone , whereas the adynamic bone limits the incorporation of Ca and P into bone it issue .
Therefore , both forms facilitate the availability of Ca and P , which ends up being deposited in soft it issues such as arteries .
The link between bone disease and vascular calcifications in CKD is now a well-established phenomenon .
2 .
Diagnostic strategies Calcium , Phosphorus They have little capacity to predict underlying bone disease , but their regular measurement is decisive for therapeutic management of the patient , especially in the dose titration stages of intestinal phosphorus binders , vitamin D analogs or calcimimetics .
Ideally , Ca++ should be used , but total Ca is routinely used .
It is recommended to adjust albumin levels in the event of hypoalbuminemia ( for each g/dL of decrease in albumin , total serum Ca decreases 0 . 9 mg/dL ) .
The following formula facilitates rapid calculation of corrected total calcium : Corrected total Ca ( mg/dL ) = total Ca ( mg/dL ) + 0 . 8 [ 4-albumina ( g/dL ) ] .
Parathyroid hormone "Intact" PTH is the biochemical parameter that best correlates with bone histology ( levels measured with the Allegro assay from Nichols Institute Diagnostics , no longer available ) .
Various assays are currently available that use antibodies against different fragments of the molecule , but they have significant intermethod variability and have not been validated .
A whole PT assay ( 1-84 ) is currently unavailable .
A consensus to establish uniform criteria for PTH measurement remains to be established .
During the dose titration stages of intestinal phosphorus binders , vitamin D analogs or calcimimetics , more frequent measurement may be required based on clinical judgment .
Calcifediol ( 25 ( OH ) D3 ) It is important to maintain adequate levels of 25 ( OH ) D3 ( > 30 ng/mL ) , since they will be the substrate for production of 1 25 ( OH ) 2 D3 , and their deficiency aggravates hyperthyroidism .
Determining 25 ( OH ) D3 levels every 6-12 months is a recommended guideline .
Other markers of bone turnover ( osteocalcin , total and bone alkaline phosphate , free pyridolines in serum , and C-terminal telopeptide of collagen ) do not improve the predictive power of PTH and therefore their systematic use is not justified .
Radiologic studies Radiologic studies are of little diagnostic utility , because biochemical changes precede radiologic changes .
Systematic radiologic evaluation of the skeleton in asymptomatic patients is not justified at present .
They are useful as the first step in the study to detect vascular calcifications and amyloidosis due to b2-microglobulin and in symptomatic and at risk patients to detect vertebral fractures .
Bone densitometry : Dual energy x-ray absorptiometry ( DEXA ) is the standard method to determine bone mineral density ( usually in the femoral neck and vertebrae ) .
It provides information on changes in bone mineral content , but not on the type of underlying bone disease .
It is useful for follow-up of bone mass or for the study of bone mass changes in the same patient .
Its value as a predictor of the risk of fracture has not been demonstrated in patients on kidney replacement therapy or with advanced chronic kidney disease .
It is indicated in patients with fractures or risk factors for osteoporosis .
Bone biopsy : The "gold standard" for diagnosis of bone disease .
With improved knowledge of the value of noninvasive parameters , its use is infrequent .
Indications : Pathological fractures in the presence or absence of minor trauma .
Symptomatic patients in the presence of incongruent clinical parameters .
A typical case is the presence of unexplained hypercalcemia from systemic disease , with inconclusive serum PTH values ( between 120-450 pg/mL as an estimated range ) .
Evaluation and follow-up of cardiovascular calcifications There are no consensuated clinical practice guidelines for the evaluation and follow-up of extraosseal calcifications in CKD .
The clinical tools for evaluation and follow-up of cardiovascular disease are used based on clinical judgment .
The periodicity of follow-up has not been established . 3 .
Recommended biochemical values The biochemical values recommended in clinical practice guidelines for the evaluation of bone mineral metabolism are summarized in Figure 3 .
The recommended PTH values do not fully coincide with the K/DOQI guidelines .
The wide variability in PTH values depending on the assays used has led us to expand the recommended PTH range in stage 3 and 4 CKD .
4 .
Treatment 4 . 1 .
Diet .
The recommended diet for the patient with CKD is traditionally based on protein restriction and phosphorus restriction for control of mineral metabolism .
A favorable circumstance is that there is a close relationship between protein and phosphorus intake .
In CKD stages 3 , 4 and 5 , it is recommended to restrict phosphorus intake to between 0 . 8-1 g/day when serum levels of phosphorus and PTH are above the recommended range .
This is approximately equivalent to a diet of 50-60 g of protein .
This reasonable antiproteinuric strategy that also restricts phosphorus intake is nutritionally safe .
What should we tell them to eat?
In a practical and oversimplified way , we recommend the following daily intake : Animal proteins : 1 serving ( 100-120 g ) , dairy products : 1 serving ( equivalent to 200-240 mL of milk or 2 yoghourts ) , bread , cereals , pastas ( 1 cup of pasta , rice or legumes + some bread or cookies ) , vegetables and fruits relatively freely , but with moderation .
4 . 2 .
Medication Vitamin D supplements should be provided if serum levels are less than 30 ng/mL .
In Spain , vitamin D3 ( cholecalciferol ) is marketed as Vitamin D3 Berenguer 2 , 000 IU/mL of solution .
Combinations of calcium with cholecalciferol are also available .
Most of the dosage forms contain approximately 500 mg of Ca+ and 400 IU of cholecalciferol .
Alternatively , calcifediol ( 25 ( OH ) D3 ) , as Hidroferol 100 mcg/mL , has been used , although the dose range is very variable and has not been established .
4 . 3 .
Phosphorus binders .
Use if hyperphosphatemia occurs .
Start with calcium-containing phosphorus binders ( calcium carbonate or calcium acetate ) , which also provide calcium if dietary intake is inadequate .
Do not exceed 1 . 5 g of Ca++ per day .
The most used are calcium carbonate and calcium acetate .
Calcium acetate shows a similar binding potency to calcium carbonate but with a lesser calcium overload , and thus would have certain advantages as well as its greater effect at different pH ranges .
However , gastric intolerance is more frequent with this dosage form .
Aluminum hydroxide may sometimes be required to control phosphoremia or the occurrence of hypercalcemia .
Serum aluminum values should be maintained below 30 mcg/L Avoid use for longer than 6 months and daily doses greater than 1 . 5 g .
Sevelamer is associated with an increased risk of acidosis and has not been approved for use in predialysis stages .
Lanthanum carbonate has been recently marketed in Spain , although its indication for use in the predialysis stage of CKD is still not approved .
4 . 4 .
Vitamin D derivatives .
Indicated when PTH levels are elevated .
A prerequisite for their use is that Ca and P serum levels are adequately controlled .
Vitamin D derivates available in Spain are 1 , 25 ( OH ) 2D3 ( Calcitriol ) and 1a ( OH ) D3 ( a-Calcidiol ) .
Doses should be titrated until PTH levels are normalized .
Phosphate binder doses often need to be increased because these vitamin D derivatives increase intestinal absorption of calcium and phosphorus .
Low doses do not cause hypercalcemia or hyperphosphatemia and do not worsen the course of renal function .
Recommended doses : Calcitriol 0 . 25 mcg every 48 hours and alpha-Calcidiol 0 . 50 mcg every 48 hours .
Soon to be available on the Spanish market is the oral dosage form of paricalcitol ( recommended initial dose of 1 mcg/24 h ) , with a lesser hypercalcemic and hyperphosphoremic effect .
Clinical use of calcimimetics in the predialysis state is not yet recommended and is currently under investigation .
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[ Sen. 78, subscore: 2.00 ]: Soon to be available on the Spanish market is the oral dosage form of paricalcitol ( recommended initial dose of 1 mcg/24 h ) , with a lesser hypercalcemic and hyperphosphoremic effect .
[ Sen. 10, subscore: 1.00 ]: Diagnostic strategies Calcium , Phosphorus They have little capacity to predict underlying bone disease , but their regular measurement is decisive for therapeutic management of the patient , especially in the dose titration stages of intestinal phosphorus binders , vitamin D analogs or calcimimetics .
[ Sen. 18, subscore: 1.00 ]: During the dose titration stages of intestinal phosphorus binders , vitamin D analogs or calcimimetics , more frequent measurement may be required based on clinical judgment .
[ Sen. 55, subscore: 1.00 ]: Most of the dosage forms contain approximately 500 mg of Ca+ and 400 IU of cholecalciferol .
[ Sen. 56, subscore: 1.00 ]: Alternatively , calcifediol ( 25 ( OH ) D3 ) , as Hidroferol 100 mcg/mL , has been used , although the dose range is very variable and has not been established .
[ Sen. 64, subscore: 1.00 ]: However , gastric intolerance is more frequent with this dosage form .
[ Sen. 66, subscore: 1.00 ]: Serum aluminum values should be maintained below 30 mcg/L Avoid use for longer than 6 months and daily doses greater than 1 . 5 g .
[ Sen. 74, subscore: 1.00 ]: Doses should be titrated until PTH levels are normalized .
[ Sen. 75, subscore: 1.00 ]: Phosphate binder doses often need to be increased because these vitamin D derivatives increase intestinal absorption of calcium and phosphorus .
[ Sen. 76, subscore: 1.00 ]: Low doses do not cause hypercalcemia or hyperphosphatemia and do not worsen the course of renal function .
[ Sen. 77, subscore: 1.00 ]: Recommended doses : Calcitriol 0 . 25 mcg every 48 hours and alpha-Calcidiol 0 . 50 mcg every 48 hours .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 11.00 |
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| Title: Tissue distribution of cadmium in rats given minimum amounts of cadmium-polluted rice or cadmium chloride for 8 months .
| | Author: Hiratsuka H Satoh S Satoh M Nishijima M Katsuki Y Suzuki J Nakagawa J Sumiyoshi M Shibutani M Mitsumori K Tanaka-Kagawa T Ando M | | Journal: Toxicol . Appl . Pharmacol . Citation: V : 160 ( 2 ) P : 183-91 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10527917 Accession (PMID): 10527917 | | Abstract: To investigate the relationship between cadmium ( Cd ) toxicity , intestinal absorption , and its distribution to various it issues in rats treated orally with minimum amounts of Cd , 14 female rats per dose group per time point were given diets consisting of 28% purified diet and 72% ordinary rice containing Cd-polluted rice ( 0 .
02 , 0 . 04 , 0 . 12 , or 1 . 01 ppm of Cd ) or CdCl ( 2 ) ( 5 . 08 , 19 . 8 , or 40 . 0 ppm of Cd ) for up to 8 months .
At 1 , 4 , and 8 months after the commencement of Cd treatment , seven rats per group were euthanized for pathological examinations to determine the Cd concentrations in the liver and kidneys and metallothionein ( MT ) in the liver , kidneys , intestinal mucosa , serum , and urine .
One week before each period of 1 , 4 , and 8 months , the remaining seven rats in each group were administered a single dosage of ( 109 ) Cd , a tracer , to match the amounts of the designated Cd doses ( about 1 . 2 to 2400 microg/kg body wt ) .
They were euthanized 5 days later to determine the distribution of Cd to various it issues .
No Cd-related toxic changes were observed .
The concentrations of Cd in the liver and kidneys at any time point and MT in the liver , kidney , serum , and urine at 4 and 8 months increased dose-dependently , whereas MT in the intestinal mucosa did not alter markedly at any time point .
The distribution rates of Cd to the liver increased dose-dependently ( 40% at lower doses to 60% at higher doses ) , whereas those to the kidney decreased dose-dependently ( 20% at lower doses to 10% at higher doses ) .
The Cd retention rates 5 days after ( 109 ) Cd administration ( amounts of Cd in various it issues/amounts of Cd administered ) ranged from 0 . 2 to 1 .
0% at any time point .
These results suggest that the distribution of Cd to the liver and kidneys after the oral administration vary depending on the dosage levels of Cd .
The difference of the distribution pattern of Cd to the liver and kidney is probably due to the difference in the form of the absorbed Cd , ie , free ion or Cd-MT complex , although not closely related to the MT in the intestinal mucosa . | Matching Sentences:
[ Sen. 8, subscore: 6.00 ]: The distribution rates of Cd to the liver increased dose-dependently ( 40% at lower doses to 60% at higher doses ) , whereas those to the kidney decreased dose-dependently ( 20% at lower doses to 10% at higher doses ) .
[ Sen. 4, subscore: 2.00 ]: One week before each period of 1 , 4 , and 8 months , the remaining seven rats in each group were administered a single dosage of ( 109 ) Cd , a tracer , to match the amounts of the designated Cd doses ( about 1 . 2 to 2400 microg/kg body wt ) .
[ Sen. 1, subscore: 1.00 ]: To investigate the relationship between cadmium ( Cd ) toxicity , intestinal absorption , and its distribution to various it issues in rats treated orally with minimum amounts of Cd , 14 female rats per dose group per time point were given diets consisting of 28% purified diet and 72% ordinary rice containing Cd-polluted rice ( 0 .
[ Sen. 7, subscore: 1.00 ]: The concentrations of Cd in the liver and kidneys at any time point and MT in the liver , kidney , serum , and urine at 4 and 8 months increased dose-dependently , whereas MT in the intestinal mucosa did not alter markedly at any time point .
[ Sen. 11, subscore: 1.00 ]: These results suggest that the distribution of Cd to the liver and kidneys after the oral administration vary depending on the dosage levels of Cd .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 9.00 |
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| Title: A biochemical-based model for the dosimetry of dietary organically bound tritium--Part 2 : Dosimetric evaluation .
| | Author: Richardson RB Dunford DW .
| | Journal: Citation: V : 85 ( 5 ) P : 539-52 Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub14571987 Accession (PMID): 14571987 | | Abstract: In this paper the dosimetry for a novel form of physiological model , whose biokinetics are governed by the overall metabolic reactions of the principal nutrients carbohydrates , fats and proteins , is evaluated by compartmental analysis .
Two models of differing complexity , called the HCNO-S and HCNO-C models , were developed from parameters evaluated in an accompanying paper .
The simpler form has single compartments representing the principal nutrients .
The more complex model includes compartments representing the longer-term retention of carbohydrates as glycogen , fats as adipose it issue , and proteins in bone and soft it issues .
The effective doses for various tritiated intakes are the same , or similar , as calculated by the two HCNO models , except for tritiated protein .
The dose coefficient for an intake of tritiated water is approximately 8% greater than that recommended by the ICRP when the tritium body burden is considered as a homogenous pool .
However , when the composition of individual organs is taken into account , the dose coefficient for an HTO intake is approximately 22% greater than the ICRP value .
The HCNO-C dose coefficient for OBT in a normal diet is 5 . 0 x 10 ( -11 ) Sv Bq ( -1 ) , which is 1 . 2-fold greater than the ICRP dose coefficient for an OBT intake .
The HCNO-C composition model gave organ and it issue doses with the largest range for a tritiated Reference Man dietary intake , the highest dose ( red marrow , then breast ) being around three-fold the lowest A property of the HCNO models , important for bioassay analyses , is that a major part ( > 90% ) of an OBT intake is oxidized and excreted as HTO , which is physiologically more accurate than the current ICRP OBT model .
The effective dose of specific tritiated foods , eg , rice and wheat , was evaluated on the basis of their constituents .
| Matching Sentences:
[ Sen. 8, subscore: 2.00 ]: The HCNO-C dose coefficient for OBT in a normal diet is 5 . 0 x 10 ( -11 ) Sv Bq ( -1 ) , which is 1 . 2-fold greater than the ICRP dose coefficient for an OBT intake .
[ Sen. 9, subscore: 2.00 ]: The HCNO-C composition model gave organ and it issue doses with the largest range for a tritiated Reference Man dietary intake , the highest dose ( red marrow , then breast ) being around three-fold the lowest A property of the HCNO models , important for bioassay analyses , is that a major part ( > 90% ) of an OBT intake is oxidized and excreted as HTO , which is physiologically more accurate than the current ICRP OBT model .
[ Sen. 1, subscore: 1.00 ]: In this paper the dosimetry for a novel form of physiological model , whose biokinetics are governed by the overall metabolic reactions of the principal nutrients carbohydrates , fats and proteins , is evaluated by compartmental analysis .
[ Sen. 5, subscore: 1.00 ]: The effective doses for various tritiated intakes are the same , or similar , as calculated by the two HCNO models , except for tritiated protein .
[ Sen. 6, subscore: 1.00 ]: The dose coefficient for an intake of tritiated water is approximately 8% greater than that recommended by the ICRP when the tritium body burden is considered as a homogenous pool .
[ Sen. 7, subscore: 1.00 ]: However , when the composition of individual organs is taken into account , the dose coefficient for an HTO intake is approximately 22% greater than the ICRP value .
[ Sen. 10, subscore: 1.00 ]: The effective dose of specific tritiated foods , eg , rice and wheat , was evaluated on the basis of their constituents .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 9.00 |
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| Title: Monte Carlo fast dose calculator for proton radiotherapy : application to a voxelized geometry representing a patient with prostate cancer .
| | Author: Yepes P Randeniya S Taddei PJ Newhauser WD | | Journal: Phys Med Biol Citation: V : 54 P : N21-8 Year: 2009 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19075361 Accession (PMID): 19075361 | | Abstract: The Monte Carlo method is used to provide accurate dose estimates in proton radiation therapy research .
While it is more accurate than commonly used analytical dose calculations , it is computationally intense .
The aim of this work was to characterize for a clinical setup the fast dose calculator ( FDC ) , a Monte Carlo track-repeating algorithm based on GEANT4 .
FDC was developed to increase computation speed without diminishing dosimetric accuracy .
The algorithm used a database of proton trajectories in water to calculate the dose of protons in heterogeneous media .
The extrapolation from water to 41 materials was achieved by scaling the proton range and the scattering angles .
The scaling parameters were obtained by comparing GEANT4 dose distributions with those calculated with FDC for homogeneous phantoms .
The FDC algorithm was tested by comparing dose distributions in a voxelized prostate cancer patient as calculated with well-known Monte Carlo codes ( GEANT4 and MCNPX ) .
The track-repeating approach reduced the CPU time required for a complete dose calculation in a voxelized patient anatomy by more than two orders of magnitude , while on average reproducing the results from the Monte Carlo predictions within 2% in terms of dose and within 1 mm in terms of distance .
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[ Sen. 9, subscore: 2.00 ]: The track-repeating approach reduced the CPU time required for a complete dose calculation in a voxelized patient anatomy by more than two orders of magnitude , while on average reproducing the results from the Monte Carlo predictions within 2% in terms of dose and within 1 mm in terms of distance .
[ Sen. 1, subscore: 1.00 ]: The Monte Carlo method is used to provide accurate dose estimates in proton radiation therapy research .
[ Sen. 2, subscore: 1.00 ]: While it is more accurate than commonly used analytical dose calculations , it is computationally intense .
[ Sen. 3, subscore: 1.00 ]: The aim of this work was to characterize for a clinical setup the fast dose calculator ( FDC ) , a Monte Carlo track-repeating algorithm based on GEANT4 .
[ Sen. 4, subscore: 1.00 ]: FDC was developed to increase computation speed without diminishing dosimetric accuracy .
[ Sen. 5, subscore: 1.00 ]: The algorithm used a database of proton trajectories in water to calculate the dose of protons in heterogeneous media .
[ Sen. 7, subscore: 1.00 ]: The scaling parameters were obtained by comparing GEANT4 dose distributions with those calculated with FDC for homogeneous phantoms .
[ Sen. 8, subscore: 1.00 ]: The FDC algorithm was tested by comparing dose distributions in a voxelized prostate cancer patient as calculated with well-known Monte Carlo codes ( GEANT4 and MCNPX ) .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 8.00 |
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| Title: Dose compensation of the total body irradiation therapy .
| | Author: Lin JP Chu TC Liu MT .
| | Journal: Citation: V : 55 ( 5 ) P : 623-30 Year: 2001 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11573795 Accession (PMID): 11573795 | | Abstract: The aim of the study is to improve dose uniformity in the body by the compensator-rice and to decrease the dose to the lung by the partial lung block .
Rando phantom supine was set up to treat bilateral fields with a 15 MV linear accelerator at 415cm treatment distance .
The experimental procedure included three parts .
The first part was the bilateral irradiation without rice compensator , and the second part was with rice compensator .
In the third part , rice compensator and partial lung block were both used .
The results of thermoluminescent dosimeters measurements indicated that without rice compensator the dose was non-uniform .
Contrarily , the average dose homogeneity with rice compensator was measured within +/- 5% , except for the thorax region .
Partial lung block can reduce the dose which the lung received .
This is a simple method to improve the dose homogeneity and to reduce the lung dose received .
The compensator-rice is cheap , and acrylic boxes are easy to obtain .
Therefore , this technique is suitable for more studies .
| Matching Sentences:
[ Sen. 1, subscore: 2.00 ]: The aim of the study is to improve dose uniformity in the body by the compensator-rice and to decrease the dose to the lung by the partial lung block .
[ Sen. 6, subscore: 2.00 ]: The results of thermoluminescent dosimeters measurements indicated that without rice compensator the dose was non-uniform .
[ Sen. 9, subscore: 2.00 ]: This is a simple method to improve the dose homogeneity and to reduce the lung dose received .
[ Sen. 7, subscore: 1.00 ]: Contrarily , the average dose homogeneity with rice compensator was measured within +/- 5% , except for the thorax region .
[ Sen. 8, subscore: 1.00 ]: Partial lung block can reduce the dose which the lung received .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
