The determination of phosphorus in Haemophilus influenzae type b conjugate vaccines by inductively coupled plasma-atomic emission spectrometry.

This study describes a method for the determination of phosphorus in lyophilized Haemophilus influenzae type b conjugate vaccines by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The concentration of polysaccharide is directly related to the concentration of phosphorus as measured in the laboratory. Phosphorus is present in the polyribosyl-ribitol phosphate (PRP) group of the Haemophilus influenzae type b conjugate vaccine. The repeating unit of PRP is 3-B-D ribose[1-1]ribitol-5-phosphate. Phosphorus in the final container is measured in microg per dose. The amount of PRP is calculated from this and reported in microg per dose. The Haemophilus influenzae type b conjugate vaccine was analyzed for phosphorus content within the range of 1.34 to 2.02 microg phosphorus per ml. The relative difference of phosphorus concentrations determined by the ICP-AES method from the phosphorus concentrations determined by the traditional colorimetric molybdate method ranged from 2.2 to 10.6%. Phosphorus spike recovery for the vaccine ranged from 93 to 99% (1.93+/-0.13 microg P/ml). The phosphorus determination of NIST SRM 3139 phosphorus spectrometric solution differed by 3.0% from the certified phosphorus value (10.00 mg P/ml).

Effects of varying dietary undegradable protein on dry matter intake, growth, and carcass composition of Holstein calves.

The objective was to study the effect of feeding diets varying in rumen undegradable protein on DMI, growth, feed efficiency, and carcass composition in Holstein calves from birth to 25 wk of age. Sixty Holstein calves were assigned in a randomized complete block design to one of three dietary treatment groups that differed in rumen undegradable protein as a percentage of total protein. Protein undegradabilities of the TMR fed for ad libitum intake for period 1 (wk 1 to 12 of age) were 33, 37, and 46% and for period 2 (wk 14 to 25 of age) were 30, 34, and 38%. Intake was not different among diets during period 1. During period 2, animals fed the highest and lowest levels of undegradable protein diet consumed less DM, and those animals on the highest undegradable diet had the least amount of crude protein intake. Feed efficiency was increased with increasing rumen undegradable protein for period 2. Carcass composition was not affected by dietary treatment for either 9-10-11 rib section or the half carcass. Prediction equations for carcass protein and fat were calculated for 25-wk Holstein calves using urea space and live weight. These results indicate that the amount of undegradable intake protein currently recommended for growing dairy replacements may not be justified when intake is ad libitum. In the present study, urea space was not found to be beneficial over live weight for predicting carcass protein and fat in intact male or female Holstein calves.

Influence of decoquinate fed to neonatal dairy calves on early and conventional weaning systems.

Forty-four Holstein calves were assigned randomly to treatments in a 2 x 2 factorial arrangement of weaning age (4 or 7 wk) and coccidiostat (treatment or control). The objective of this study was to compare the effectiveness of a coccidiostat, decoquinate, on health parameters and growth of neonatal dairy calves on early and conventional weaning systems. Calves weaned at 4 wk had greater intakes of grain in wk 5 to 7 than did calves weaned at 7 wk. Differences in intakes between weaning groups were not apparent from wk 8 to 24. Fecal coccidia oocyst counts were not affected by age at weaning but were affected by coccidiostat feeding at the rate of .5 mg/kg BW/d offered from 3 d of age and throughout the trial. No effects due to age at weaning or coccidiostat treatment were found in plasma glucose, urea N, and minerals (Ca, P, Na, Cl, K, Mg). Growth parameters were significantly increased in treated animals. Total BW was increased (wk 9 to 24) in treated over control calves (127.3 versus 118.5 kg). Height at withers was also increased in treated calves (95.0 vs. 92.8 cm). Coccidiosis treatment increased growth of dairy calves from 9 to 24 wk, but no interactions were found between coccidiosis treatment and age at weaning.

Gut reactions of radioactive nitrite after intratracheal administration in mice.

Intratracheal administration to mice of radioactive nitrite labeled with nitrogen-13 (13NO2-) (half-life, 9.96 minutes) in dosages that do not cause pharmacological perturbation reveals that oxidative and reductive reactions occur in different organs. Oxidation of 13NO2- to radioactive nitrate (13NO3-) predominates in the blood and liver. Reduction of 13NO2- occurs in those mice that harbor intestinal microflora; this reduction does not occur in germ-free mice. The intestinal reduction products include ammonium, glutamate, glutamine, and urea. With a detection limit of about 0.01 percent of the instilled nitrogen-13, no labeled nitrosamines were detected within 30 minutes. Reduced nitrogen-13 is transported out of the intensive into the circulatory system and appears in the urine along with 13NO3-. The biological half-period for 13NO2- destruction is about 7 minutes, and both oxidation and reduction products are formed.

Effect of n-butyrate on DNA synthesis in chick fibroblasts and HeLa cells.

n-Butyrate in low concentrations stops reversibly the proliferation of chick embryonic fibroblasts and of HeLa cells, shutting off DNA synthesis. Extensive acetylation of histones is seen at the same time as inhibition of DNA synthesis. Nuclei from n-butyrate-treated HeLa cells remain inactive in control cytosol; control nuclei are strongly inhibited by cytosol from treated cells.