Microdialysis in early detection of temporary pancreatic ischemia in a porcine model.

BACKGROUND: Ischemic injury to the pancreas occurs in various clinical conditions. A method for online monitoring of pathophysiological events in pancreatic parenchyma is missing. AIMS: To assess the timing of microdialysis (MD) technique response on temporary changes in pancreatic perfusion, and to evaluate the relationship between MD data and systemic markers of anaerobic metabolism and inflammation. METHODS: In anaesthetized normoventilated pigs, MD probes were placed in right (control) and left (ischemic) pancreatic lobes, respectively. Following the clamping of the vessels, ischemia was verified by tissue oxygen tension (P(ti)O(2)) measurements. RESULTS: P(ti)O(2) decreased within 20 min after the clamping of the vessels, already returning to baseline levels at the first sampling point after the removal of the clamp. MD lactate levels increased, whereas pyruvate and glucose levels decreased at 20 min after the induction of ischemia. These trends continued until the end of ischemia and returned to baseline following reperfusion. Serum lactate, amylase and tumor necrosis factor-alpha levels decreased throughout the protocol time. CONCLUSION: MD data were in concordance with changes in P(ti)O(2), which is indicative of local anaerobic metabolism. MD allowed the detection of pathophysiological processes within the ischemic pancreas at a stage when no elevations of systemic markers of ischemia or inflammation were observed.

Ethylene glycol intoxication misdiagnosed as eclampsia.

Ethylene glycol intoxication is one of the most serious acute poisonings with very uncertain prognosis with regard to both recovery and survival. A case report is presented in which a woman who was admitted for the termination of pregnancy by Caesarean section with a diagnosis of eclampsia turned out to be severely intoxicated by ethylene glycol.

Glycerol kinase of Trypanosoma brucei. Cloning, molecular characterization and mutagenesis.

Trypanosoma brucei contains two tandemly arranged genes for glycerol kinase. The downstream gene was analysed in detail. It contains an ORF for a polypeptide of 512 amino acids. The polypeptide has a calculated molecular mass of 56 363 Da and a pI of 8.6. Comparison of the T. brucei glycerol kinase amino-acid sequence with the glycerol kinase sequences available in databases revealed positional identities of 39.0-50.4%. The T. brucei glycerol kinase gene was overexpressed in Escherichia coli cells and the recombinant protein obtained was purified and characterized biochemically. Its kinetic properties with regard to both the forward and reverse reaction were measured. The values corresponded to those determined previously for the natural glycerol kinase purified from the parasite, and confirmed that the apparent Km values of the trypanosome enzyme for its substrates are relatively high compared with those of other glycerol kinases. Alignment of the amino-acid sequences of T. brucei glycerol kinase and other eukaryotic and prokaryotic glycerol kinases, as well as inspection of the available three-dimensional structure of E. coli glycerol kinase showed that most residues of the magnesium-, glycerol- and ADP-binding sites are well conserved in T. brucei glycerol kinase. However, a number of remarkable substitutions was identified, which could be responsible for the low affinity for the substrates. Most striking is amino-acid Ala137 in T. brucei glycerol kinase; in all other organisms a serine is present at the corresponding position. We mutated Ala137 of T. brucei glycerol kinase into a serine and this mutant glycerol kinase was over-expressed and purified. The affinity of the mutant enzyme for its substrates glycerol and glycerol 3-phosphate appeared to be 3. 1-fold to 3.6-fold higher than in the wild-type enzyme. Part of the glycerol kinase gene comprising this residue 137 was amplified in eight different kinetoplastid species and sequenced. Interestingly, an alanine occurs not only in T. brucei, but also in other trypanosomatids which can convert glucose into equimolar amounts of glycerol and pyruvate: T. gambiense, T. equiperdum and T. evansi. In trypanosomatids with no or only a limited capacity to produce glycerol, a hydroxy group-containing residue is found as in all other organisms: T. vivax and T. congolense possess a serine while Phytomonas sp., Leishmania brasiliensis and L. mexicana have a threonine.

Studies on the karyotype and gametogenesis in Trichuris muris.

The cytological study of males and females of Trichuris muris (Schrank, 1788) revealed the diploid number of chromosomes to be 2n = 6. The sex determining mechanism was XX female/XY male. All the chromosomes were subtelocentric. Sex chromosomes formed the smallest pair, but X and Y were difficult to distinguish morphologically. Chromosome changes during gametogenesis in both sexes followed a classical pattern except in the male prophase and metaphase I. Four male autosomes formed two bivalents, each with one proximal chiasma with strict localization, while sex chromosomes X and Y formed two univalents. Female chromosomes formed three rod bivalents of normal type, which possessed three, two and two chiasmata.