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Biomedical subjects

T L Huber

Publications and source records attributed to T L Huber.

At least 37 records · Page 2Linked to original sources

Effects of promethazine on hemorrhagic shock in the dog.

The effects of pre- and post-treatment with promethazine, an antihistamine, in hemorrhage-shocked dogs were investigated. Survival to 6 hours was enhanced in the dogs given (IM administration) the H1-receptor antagonist at 1 hour before hemorrhage was induced when compared with survivals of saline-treated control dogs (3 of 5 dogs vs 1 of 5 dogs). Furthermore, 4 of 5 dogs given (IV administration) promethazine at 30 minutes after the initial hemorrhage survived. Promethazine treatment by either route increased mean arterial pressure among surviving dogs throughout the 6-hour experimental period.

Animals↗

Effect of hypocalcemia on motility of the ruminant stomach.

The sensitivity of ruminal and abomasal contractions to hypocalcemia was evaluated in sheep. Serum diffusible calcium concentrations were determined during induction of hypocalcemia (IV infusion of Na2EDTA) and recovery from hypocalcemia (no infusion). Contractile strength of the rumen gradually decreased as serum diffusible calcium concentrations decreased; significant correlation (r = 0.75; P less than 0.001) was observed. Ruminal contractions disappeared before clinical signs of hypocalcemia were seen. Abomasal contractions were slightly reduced when serum diffusible calcium concentrations were equal to those producing ruminal stasis and clinical signs of hypocalcemia. These observations indicated that ruminal dysfunction may occur considerably before the onset of clinical signs of hypocalcemia.

Abomasum↗

Kinetics of gentamicin after intravenous, intramuscular, and intratracheal administration in sheep.

Kinetics of gentamicin (2.2 mg/kg of body weight) were investigated in 7 sheep after IV bolus administration. The mean serum concentration profile could be described by a 2-compartment open model with a distribution rate constant (alpha) of 3.112 +/- 1.681 hour-1 [half-life, t1/2(alpha) = 17.22 +/- 8.63 minutes] and an overall elimination rate constant (beta) of 0.485 +/- 0.028 hour-1 [t1/2(beta) - 85.87 +/- 5.03 minutes]. The apparent volume of distribution was somewhat restricted [Vd(area) = 0.194 +/- 0.059 L/Kg], and the total body clearance was 1.559 +/- 0.400 ml/kg/min. Equal dosages of gentamicin (2.2 mg/kg) were also given IM and intratracheally (IT). after IM injection, gentamicin reached peak serum concentration at postinjection minutes (PIM) 45, surpassing concentrations after the IV injection for the remainder of the experiment. The IT injection produced detectable serum concentrations at PIM 5, with a peak concentration at PIM 60. The serum drug concentrations after IT injections remained well below concentrations after IV and IM injections. Radiographic analysis of an IT injection of a gentamicin-tantalum suspension revealed good distribution throughout the trachea and proximal bronchi, with physical clearance of the tantalum occurring after greater than or equal to 10 minutes. Aspiration biopsy of the tracheal wash 6 hours after IT gentamicin injection revealed no cytologic response to gentamicin in 6 of 7 sheep, with the single response that of a purulent exudate.

Animals↗

Endotoxin absorption in hay-fed and lactic acidotic sheep.

Absorption of endotoxin from the gastrointestinal tract was evaluated in hay-fed and lactic acidotic sheep duodenally infused with 10 mg of Escherichia coli endotoxin, and in lactic acidotic sheep not infused. The effect of abomasal fluid on biological activity of endotoxin was also evaluated. Leukopenia was the criterion used for detecting endotoxemia. Absorption of endotoxin from the gastrointestinal tract was not detected in either hay-fed or lactic acidotic sheep. Endotoxin appeared to maintain its activity after incubation with abomasal fluid, and the presence of endogenous endotoxin in abomasal contents was indicated. The results indicate that endotoxin of alimentary origin may not be involved in the lactic acidosis syndrome in ruminants.

Abomasum↗

Effect of ruminal lactic acid-utilizing bacteria on adaptation of cattle to high-energy rations.

Heifers, unadapted to a concentrate ration, were intraruminally inoculated (1 dose) with cultures of ruminal lactic acid-utilizing bacteria or with ruminal fluid from a steer adapted to a concentrate ration. Inoculation with cultures (1 L) of Selenomonas ruminantium or Megasphaera elsdenii did not produce better average daily weight gains or feed efficiency of heifers fed a high-energy ration for 21 days, if these values were compared with the performance of noninoculated heifers. Average daily weight gain and feed efficiency of heifers inoculated with 1 L of Peptococcus asaccharolyticus culture or with 1 L of adapted ruminal fluid and fed a high-energy ration for 21 days were better if these values were compared with the performance of noninoculated heifers.

Animal Feed↗

Lactic acid-utilizing bacteria in ruminal fluid of a steer adapted from hay feeding to a high-grain ration.

A mature, rumen-cannulated steer fed Coastal Bermuda grass hay for 8 weeks was adapted to a high-grain ration by stepwise increases in grain over a period of 4 weeks. The grain rations had concentrate-to-roughage ratios of 40:60, 70:30, and 85:15 and were fed for 10, 7, and 11 days, respectively. Numerical estimates of lactate-utilizing bacteria in ruminal fluid of the steer the last 3 days each ration was fed were made by colony counts. Lactate-utilizing bacteria were identified as Megasphaera elsdenii, Peptococcus asaccharolyticus, and Selenomonas ruminantium. Maximal numbers of lactate-utilizing bacteria were observed in the ruminal fluid of the steer during feeding the concentrate-to-roughage ration of 70:30.

Animal Feed↗

Studies of mechanisms of action of secretin and pancreozymin on rumen motility.

Rapid intravenous administration of a single bolus of secretin caused a marked decrease in both amplitude and frequency of rumen contractions, whereas pancreozymin administration caused a decrease in frequency but an increase in amplitude of rumen contractions. Alpha receptor blockade with phenoxybenzamine or beta receptor blockade with propranolol did not alter secretin or pancreozymin effects on rumen motility. Blockade of histamine receptor sites with tripelennamine did not prevent the secretin-induced decrease of rumen motility. A marked similarity in the decreased rumen motility pattern was observed when secretin effects were compared to aminophylline effects.

Animals↗