Taurine supplementation at three different dosages and its effect on trauma patients.

We studied the effect of different amounts of intravenous taurine supplementation on restoring serum taurine concentrations in trauma patients. The nature of the hypotaurinemia in trauma patients was also studied by following renal-clearance dynamics. Five trauma patients in each of four groups were randomly assigned to receive, in their parenteral nutrition solutions, one of three dosages of taurine (5, 10.8, or 50 mg/kg ideal body wt as group 1, 2, or 3, respectively) or no taurine. Serum taurine concentrations rose significantly over 7 d, relative to control values, in both groups 2 and 3, but even with the highest dosage (group 3) only recovered about one-half of the deficit to the normal value. Despite low serum taurine concentrations in group 3, in contrast with handling of other amino acids, tubular reabsorption of taurine remained abnormally low after 7 d, resulting in a large taurine excretion. Hypotaurinemia in trauma patients persists longer than other hypoaminoacidemias because of depressed renal tubular reabsorption. Even 7 d of a high-dose taurine supplementation does not fully correct the hypotaurinemia of trauma.

Taurine concentrations in serum of critically injured patients and age- and sex-matched healthy control subjects.

Sulfur-containing amino acid concentrations were measured in serum of nine previously healthy adult trauma patients after 7 d of taurine-free parenteral nutrition and were compared with fasting serum concentrations in age- and sex-matched healthy subjects. Serum taurine concentrations in the patient group were depressed by 60% relative to control values (P less than 0.05) whereas serum methionine concentrations were significantly higher in the patient group. Serum cysteine concentrations were not significantly different between the two groups. This early decline in serum taurine concentrations in unsupplemented trauma patients suggests that taurine may be essential in the post-injury state.

A redesigned corneal holder for the bovine cornea opacity and permeability assay that maintains normal corneal morphology.

The bovine cornea opacity and permeability assay (BCOP) has been in use for nearly 10 years but has not been submitted for regulatory approval. In previous reports we have presented corneal hydration and endothelial damage as additional endpoints in this assay and have suggested that the design of the BCOP's corneal holder should be modified. The standard holder used in the BCOP assay induces physical damage to the cornea because it contacts clear cornea causing edge damage to the epithelial, stromal and endothelial layers. Second, by forcing a curved, oval-shaped bovine cornea into a flat, circular opening, corneal wrinkling occurs which can alter the cornea's optical characteristics and, most importantly, induces endothelial damage. We now report on a redesigned BCOP corneal holder that clamps onto the sclera, maintains normal corneal shape and does not cause damage to the endothelium. This ensures that irritancy tests are conducted using healthy, anatomically normal tissue. Tests of this holder using acetone, trichloroacetic acid, isopropanol and benzalkonium chloride show that it is now possible to evaluate effects of chemical substances on the endothelium. The effects of these compounds on corneal opacity and hydration in the new holder are similar to their effects on the cornea in the standard holder.

Enteral nutrient solutions. Limiting bacterial growth.

Bacterial contamination of enteral nutrient solutions ( ENS ) in FFcess of food product standards is known to occur in the hospital setting. The large amounts of bacteria often given with ENS have been shown to create a reservoir for nosocomial infections, and nonpathogenic bacteria have been implicated. Patient tolerance is dependent on immune status and the bacterial load delivered to the gut. The purpose of this study was to evaluate the bacterial growth-sustaining properties of various ENS and to devise methods to limit bacterial growth. Five commercial products were prepared under sterile conditions. After inoculation with approximately 5 X 10(3) organisms/cm3 of Enterobacter cloacae, each solution was hung at room temperature for 24 hours with samples drawn at fixed intervals and plated for bacterial counts. Bacterial growth rates in Ensure, Travasorb , and Vital were markedly higher than those in Precision and Vivonex. Vivonex was noted to contain potassium sorbate (KS) used as a fungistatic agent. Recent studies have identified KS as a broad-spectrum bacteriostatic food preservative that is federally approved for this use. KS (0.03%) was added to Travasorb inoculated with 5 X 10(3) organisms/cm(3) of E. cloacae. The bacterial growth rate was reduced by 75 per cent, and the final count of 2-3 X 10(4) organisms/ml was within the federally regulated limit for milk. This study suggests that initial inoculum, growth rate, and hang time can be altered to provide a significant reduction in final bacterial counts in ENS .

Assay for taurine conjugates of bile acids in serum by reversed-phase high-performance liquid chromatography.

The purpose of this study was to develop a new high-performance liquid chromatographic (HPLC) procedure for quantifying taurine conjugates of bile acids in serum. The technique involved three basic steps. The first removed free amino acids via solid-phase extraction of the serum. The second step involved the reaction of the extracted serum with the enzyme choloylglycine hydrolase, which liberated the taurine from the conjugated bile acids. The third step was the reversed-phase HPLC separation of o-phthalicdicarboxaldehyde derivatives of taurine. The assay provides a simple technique for determination of the total amount of taurine-conjugated bile acids in serum.

Effects of time, temperature, and preservative on bacterial growth in enteral nutrient solutions.

Bacterial contamination and the effects of time, temperature, and preservative on bacterial growth in enteral nutrient solutions were studied. Bacteria were counted after 24-hour incubation of five samples of frozen Travasorb STD (Travenol Laboratories) from the pharmacy and five samples freshly reconstituted in the dietary department. Growth in samples of Travasorb STD prepared in the pharmacy was studied after (1) fresh mixing, 24-hour refrigeration, and 12 hours at room temperature, (2) freezing, thawing, and 12 hours at room temperature, and (3) freezing, thawing, 24-hour refrigeration, and 12 hours at room temperature. Duplicate samples of five products [Ensure (Ross Laboratories), Precision LR (Doyle Pharmaceuticals), Travasorb STD, Vital (Ross Laboratories), and Vivonex STD ( Norwich -Eaton)] were inoculated with Enterobacter cloacae, and growth curves for 24 hours were plotted. This challenge study was repeated using Travasorb STD as a control and Travasorb STD with potassium sorbate added. Bacterial contamination following reconstitution was not significantly different between pharmacy and dietary department samples. Growth after 12 hours at room temperature was not significantly different for the three sets of storage conditions. Logarithmic growth occurred only at room temperature. All products supported growth of E. cloacae, but growth was significantly lower in Vivonex STD (which contains potassium sorbate) and Precision LR. Growth was reduced by 70% versus control at 12 hours in Travasorb STD containing 0.036% potassium sorbate and by 90% with 0.2% potassium sorbate. Microbial growth in enteral nutrient solutions was dependent on the initial inoculum and the storage time at room temperature. Addition of potassium sorbate to these solutions may greatly reduce bacterial growth.

Assessment of caloric needs in stressed patients.

An accurate assessment of the energy needs of hospitalized patients is necessary to fulfill caloric requirements, yet avoid inducing complications associated with excessive energy provisions. The objective of this study was to compare actual energy needs as determined by indirect calorimetry with several methods for estimating energy needs. These included the Harris-Benedict Equation (HBE), HBE plus factors for stress (ie, trauma, surgery, cancer), Wilmore 's nomogram, and estimates using 25 and 35 kcal/kg. One hundred nineteen parenteral nutrition patients were studied. HBE or the method of 25 kcal/kg was found to be most accurate in predicting energy needs. Stress factor adjustments of HBE significantly overestimated energy needs when compared to indirect calorimetry, as did the use of Wilmore 's nomogram and the factor of 35 kcal/kg.