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urea nitrogen and serum creatinine, triiodothyronine (T3) and thyroxine (T4) levels. Findings . Table 1 Relation between blood urea nitrogen (BUN) and serum creatinine . The publication can be obtained from: Marketing and Dissemina-. Creatinine is essentially a metabolite of creatinine phosphate, a compound that Radiometer launches CE-marked point-of-care tests for creatinine and urea. Glomerular filtration rate and levels of electrolytes, urea and creatinine give a strong indication of kidney function and can guide treatment.
Diurnal variations in milk urea, protein and lactose concentrations in Holstein dairy cows. Evaluation of the blood glucose, Beta-hydroxy butric acid and urea concentrations in non-pregnant ewe flocks in Urmia, Iran. Relation of plasma concentration of urea, glucose and total protein to milk levels of urea, lactose and protein of grazing ewes during lactation.
Mineral metabolism in calves during periods of milk feeding and weaning based on selected parameters in the blood. Effects of parity, days in milk, milk production and milk components on milk urea nitrogen in Chinese Holstein. J Anim Vet Adv. Prediction of ammonia from dairy cattle manure based on milk urea nitrogen: Relation of milk urea nitrogen to urine urea nitrogen excretion. Relation-ships among milk urea-nitrogen, dietary parameters, and fecal nitrogen in commercial dairy herds.
Can J Vet Res. Clinico-biochemical studies on induced pregnancy toxemia in sheep. Ind J Vet Pathol. Plasma and milk urea nitrogen in relation to pregnancy rate in lactating dairy cattle.
Relationship between milk urea concentration and cow fertility. Relationships between milk protein composition, milk protein variants, and cow fertility traits in Dutch Holstein-Friesian cattle. Genetic and nongenetic variation in concentration of selenium, calcium, potassium, zinc, magnesium, and phosphorus in milk of Dutch Holstein-Friesian cows.
Gabris J, Bajan L. Use of milk urea nitrogen to improve dairy cow diets. Seasonal and regional effects on milk composition of dairy cows in South Korea. J Anim Sci Tech. The analysis of milk components and pathogenic bacteria isolated from bovine raw milk in Korea. Milk urea nitrogen and fertility in dairy farms. Evaluation of milk urea concentration as useful indicator for dairy herd manage-ment: Asian J Anim Vet Adv.
Haemoconcentration in yankasa sheep exposed to prolonged water deprivation. Biochemical profile of rumen liquor, blood and urine in experimental acidosis in sheep. Relationship between the frequency of placental retention and serum magnesium values in cows. Aphosphorosis in north Yemen cattle. Low flow, as in urinary tract obstruction, allows more time for reabsorption and is often associated with increases in antidiuretic hormone ADHwhich increases the permeability of the terminal collecting tubule to urea.
During ADH-induced antidiuresis, urea secretion contributes to the intratubular concentration of urea. The subsequent buildup of urea in the inner medulla is critical to the process of urinary concentration.
Reabsorption is also increased by volume contraction, reduced renal plasma flow as in congestive heart failure, and decreased glomerular filtration. Creatinine formation begins with the transamidination from arginine to glycine to form glycocyamine or guanidoacetic acid GAA. This reaction occurs primarily in the kidneys, but also in the mucosa of the small intestine and the pancreas.
In a reaction catalyzed by creatine phosphokinase CPKmost of this muscle creatine is phosphorylated to creatine phosphate. Modified from Dosseter, Thus, creatinine production essentially reflects lean body mass. Because this mass changes little from day to day, the production rate is fairly constant. Absolute creatinine production declines with age in line with decreasing muscle mass. Unlike urea, creatinine is largely unaffected by gastrointestinal bleeding or by catabolic factors such as fever and steroids.
However, the ingestion of cooked meat can raise the sCr because cooking converts the creatine in meat to creatinine. Certain drugs, notably the psychoactive phenacemide, can increase the production rate. Like urea, creatinine distributes throughout total body water.
Its concentration in serum is a function of the usually constant production and excretion rates. It may be slightly higher in the evening than in the morning, due most likely to dietary meat intake by day. In normal subjects, creatinine is excreted primarily by the kidneys.
There is minimal extrarenal disposal or demonstrable metabolism. As a small molecule molecular weight of daltonsit is freely filtered by the glomerulus. Unlike urea, it is not reabsorbed or affected by urine flow rate. Excretion of both urea and creatinine is increased during exercise without producing significant change in serum concentration.
The amount excreted has been used as a rough index of the completeness of daily urine collection. Measurement of urine creatinine excretion is used in calculating the creatinine clearance cCr.
bun serum creatinine: Topics by dubaiairporthotel.info
Short of the more precise but technically impractical inulin clearance, the cCr is the standard clinical tool for estimating GFR, especially in the early stages of renal disease. In contrast, the cCr has the major disadvantage of inaccuracies in urine collection, especially during short-term clearances or in patients with low urine volumes.
For this reason, hour clearances are preferred for general use, because the usually larger volumes will minimize errors of collection. The concentration of creatinine in the serum and urine is determined, and with careful attention to the units of measurement, the cCr is calculated as follows: The result may then be standardized to 1. The subject's BSA is related to weight and height and is usually obtained from a nomogram. Several shortcuts to estimate the cCr without collecting urine have been proposed.
The earliest and probably the least accurate ignores the subject's age and weight, and simply divides by the sCr. The Cockcroft-Gault formula is the one usually recommended for use in calculating dosage of drugs especially nephrotoxic antibiotics.
It takes into account the well-documented fall in GRF with age as follows: In advanced renal failure, net creatinine excretion decreases significantly. Further, there is measurable creatinine metabolism by gut flora and, in some patients, decreased creatinine synthesis. Thus cCr is unreliable and often overestimates GFR in chronic renal failure and in cirrhosis.
Certain drugs may affect cCr without changing GFR.
Salicylates, cimetidine, and trimethoprim interfere with tubular secretion of creatinine and cause a spuriously low cCr. Because they are handled primarily by glomerular filtration with little or no renal regulation or adaptation in the course of declining renal function, they essentially reflect GFR.
Unfortunately, their relation to GRF is not a straight line but rather a parabolic curve Figure Within that range, however, a doubling of the values e.
Therefore, in the early stages of renal disease, these tests could create a false sense of security. Random values above the midrange of normal should be corroborated by a normal cCr before one can confidently tell a patient that his or her kidney function is normal.
At the other end of the curve, small changes in kidney function can produce large increments in BUN and sCr. Here, these tests are generally adequate to follow a patient's course. Indeed, the reciprocal of the sCr plotted against time shows a straight-line progression of renal disease in each individual patient, and can be used to predict the advent of end-stage renal disease. At all stages of renal insufficiency, the sCr is a much more reliable indicator of renal function than the BUN because the BUN is far more likely to be affected by dietary and physiologic conditions not related to renal function Table The stages of renal failure have been defined according to the sCr as follows: With so many limitations on the usefulness of the BUN, one wonders why the test survives.
When taken with the sCr, it is a very useful clue to the presence of a prerenal or postrenal component to azotemia. Other factors being normal, a patient with an sCr of 5. Note that this 10 to 1 ratio applies best in moderate to advanced renal failure. Attention to these reversible complications of uremia can give a patient a reprieve from an untimely sentence of end-stage renal disease.
The BUN survives and is finding wide application in the nutritional management of critically ill patients.
The urea nitrogen appearance UNA objectively lets the intensivist know whether the patient's nitrogen needs are being met.