Purification and characterization of a branched-chain amino acid aminotransferase from Lactobacillus paracasei subsp. paracasei CHCC 2115.

AIM: Purification and characterization of an aminotransferase (AT) specific for the degradation of branched-chain amino acids from Lactobacillus paracasei subsp. paracasei CHCC 2115. METHODS AND RESULTS: The purification protocol consisted of anion exchange chromatography, affinity chromatography and hydrophobic interaction chromatography. The enzyme was found to exist as a monomer with a molecular mass of 40-50 kDa. The AT converted isoleucine, leucine and valine at a similar rate with alpha-ketoglutarate as the amino group acceptor; minor activity was shown for methionine. The enzyme had pH and temperature optima of 7.3 and 43 degrees C, respectively, and activity was detected at the pH and salt conditions found in cheese (pH 5.2, 4% NaCl). Hg2+ completely inhibited the enzyme, and the inhibition pattern was similar to that for pyridoxal-5'-phosphate-dependent enzymes, when studying the effect of other metal ions, thiol- and carbonyl-binding agents. The N-terminal sequence of the enzyme was SVNIDWNNLGFDYMQLPYRYVAHXKDGVXD, and had at the amino acid level, 60 and 53% identity to a branched-chain amino acid AT of Lact. plantarum and Lactococcus lactis, respectively. CONCLUSIONS: The results suggest that Lact. paracasei subsp. paracasei CHCC 2115 may contribute to development of flavour in cheese. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of this work contribute to the knowledge of transamination performed by cheese-related bacteria, and in the understanding and control of amino acid catabolism and the production of aroma compounds.

[Bupivacaine in spinal anesthesia. The spread of analgesia--dependence on baricity, positioning, dosage, technique of injection and patient characteristics]. / Bupivakain til spinalanaestesi. Analgesiens udbredelse--afhoengighed af baricitet, lejring, dosis, injektionsteknik og patientkarakteristika.

The spread of sensory blockade during spinal analgesia using bupivacaine is influenced by a number of factors concerning baricity, positioning, dosage, technique of injection and patient characteristics. The glucose-free 0.5%-solution acts as a hypobaric solution. The interaction of baricity and posture during and immediately after the injection of this solution is of utmost importance. However, the level of analgesia when using hyperbaric solutions seems not to be affected by posture. The dose of bupivacaine is also of great importance, independent of the type of solution used. Of modest importance is patient age, irrespective of baricity, while obesity and injection level only matter when the glucose-free solution is used. Injection speed seems of modest importance, while barbotage and direction of the needle have no or minimal clinical importance. The problem of unpredictability of the sensory blockade, a major one in spinal analgesia, is yet to be solved.

Level of injection in spinal anesthesia: effect on sensory anesthetic level.

BACKGROUND AND OBJECTIVES: A prospective, randomized study was performed to investigate the influence of the level of injection on sensory anesthesia when bupivacaine 0.5% adjusted to 37.0 C was used. METHODS: Three milliliters of plain bupivacaine 0.5% were injected at either the L2-3 interspace or the L4-5 interspace. There were 10 patients in each group. The patients were kept sitting for 2 minutes after injection. RESULTS: No significant difference in maximal level of sensory anesthesia was found (p = 0.123). CONCLUSION: These preliminary results indicate that if a higher level of injection is more suitable for anatomic reasons, it can safely be used without the risk of a much higher level of sensory blockade.

Influence of temperature of bupivacaine on spread of spinal analgesia.

A prospective, randomised study was performed to investigate the influence of temperature on sensory blockade in spinal anaesthesia. Three ml of plain bupivacaine 0.5% were injected intrathecally at either 4 degrees C, room temperature, or 37 degrees C. There were 10 patients in each group, who were kept sitting for 2 minutes after injection. The maximum level of sensory blockade was significantly higher (p less than 0.01) in the group who received the solution adjusted to 37 degrees C, and variability of level was smaller (p less than 0.05). Time to two-segment regression was shorter in the 37 degrees C group than in the 4 degrees C group (p less than 0.05). Hypotension required administration of ephedrine more often in the 37 degrees C group (p less than 0.05). It is concluded that the use of plain bupivacaine 0.5% adjusted to 37 degrees C results in a higher and more predictable sensory blockade.