Investigations using ammonium citrate-(15)N and urea-(15)N showed that children in the acute stage of kwashiorkor and marasmus receiving a diet of adequate protein content retained a considerable percentage of the label from both compounds. Excretion of both total (15)N and urea-(15)N was subnormal and elimination was virtually completed 36 hr after administration of the isotope. During recover...

1. In focal and diffuse necroses of the liver due to haemotoxic sera there occurs an increased elimination of total nitrogen with a corresponding augmented output of urea. The ammonia excretion becomes slightly diminished at first, but later rises somewhat above normal. The undetermined nitrogen is markedly increased. 2. In diffuse degeneration with no necrosis on the other hand only a slightly...

The objective of this review is to describe recent research findings related to the use of milk or blood urea nitrogen to identify inefficiencies in protein nutrition and estimate nitrogen excretion. A mathematical model was developed to integrate milk urea nitrogen (MUN) and milk composition to predict urinary and fecal excretion, intake, and utilization efficiency for nitrogen in lactating da...

Although many methods for the determination of urea nitrogen have been described, few have proved highly convenient for the accurate determination of small amounts of urea nitrogen without having to make use of special apparatus or techniques. Among the older methods, the Van Slyke gasometric method (1) is generally considered the most accurate, with an allowable error of 1 per cent. This metho...

Alpha keto-analogues of valine, leucine, isoleucine, methionine, phenylalanine, and (in one instance) tryptophan and histidine, along with the remaining essential amino acids, were administered orally to 10 patients with severe chronic uremia fed a diet low in protein but adequate in calories. Ketoacid dosage varied from 6 to 14 g daily, as sodium or calcium salts. Net nitrogen intake, calculat...

It has been well documented that a negative relationship exists between blood, plasma, or milk urea nitrogen and fertility in dairy cattle, with increased concentrations of plasma urea nitrogen (PUN; > 19 mg/dL) and milk urea nitrogen (MUN; > 15.4 mg/dL) being associated with suppressed fertility. Although this relationship is not fully understood, likely contributing factors have been suggeste...

Urea Nitrogen to Creatinine Ratio Related Information: Creatinine, Serum or Plasma Osmolality, Serum Urea Nitrogen, Serum or Plasma Synonyms: BUN to Creatinine Ratio Test includes: Serum creatinine and serum urea nitrogen. Background: Useful to distinguish between preand postrenal diseases, gastrointestinal bleeding, and renal diseases. High BUN/creatinine ratio: Decreased renal perfusion, hypo...

A monitoring program with a weekly sampling frequency over a 15-month period indicates that urea concentrations above a certain threshold level may trigger the blooms of Alexandrium catenella in Thau lagoon. However, urea concentrations were also sometimes related to ammonium and dissolved organic nitrogen concentrations, indicating that the role of urea may not be a direct one. An original app...

According to the usually accepted concept, the urea removed from the blood by the kidneys is excreted in two forms, chiefly as urea itself, but partly as ammonia. That the ammonia of the urine is formed in the kidneys was demonstrated by Nash and Benedict (1921), in work which has been confirmed by other authors (cf. Peters and Van Slyke, I, p. 373). Evidence from animal experiments in v4vo has...

After synthesis during the early log phase, the concentrations of ubiquinone and cytochromes did not vary during the growth cycle of Azotobacter vinelandii, when grown with either high or low aeration on nitrogen-free or urea-containing media. The level of aeration had no effect on the concentrations of the electron carriers synthesized, but affected the growth rate. On urea-containing medium, ...