Analysis of myeloperoxidase activity in wound fluids as a marker of infection

Background

Neutrophilic polymorphonuclear leukocytes play a crucial role in the host defence against bacterial and fungal infections. They participate in the inflammatory response through the liberation of peptides and enzymes like myeloperoxidase (MPO). Therefore, MPO has a potential as a marker enzyme for the diagnosis of wound infection.

Methods

Substrate specificities and reaction pathways of MPO were investigated for new MPO substrates: crystal violet, leuco crystal violet, fast blue RR (4-benzoylamino-2,5-dimethoxybenzenediazonium chloride hemi(zinc chloride) salt) and various systematically substituted model substrates based on 2,7-dihydroxy-1-(4-hydroxyphenylazo)naphtalene-3,6-disulphonic acid. In addition, fast blue RR was covalently bound to siloxanes allowing immobilization of the substrate, while cellobiosedehydrogenase was integrated for generation of hydrogen peroxide required by MPO.

Results

Elevated concentrations of MPO were found in infected wounds compared with non-infected wounds (92.2 ± 45.0 versus 1.9 ± 1.8 U/mL). Various soluble and immobilized substrates were oxidized by MPO in wound samples and the influence of substrate structure and reaction pathways were elucidated for selected compounds.

Conclusions

Incubation of different MPO substrates with infected wound fluid samples resulted in a clear colour change in the case of elevated MPO concentrations, thus allowing early diagnosis of wound infection.

Increased cytosolic Ca2+ amplifies oxygen radical-induced alterations of the ultrastructure and the energy metabolism of isolated rat pancreatic acinar cells

BACKGROUND

Oxygen radicals have been implicated as important mediators in the early pathogenesis of acute pancreatitis, but the mechanism by which they produce pancreatic tissue injury remains unclear. We have, therefore, investigated the effects of oxygen radicals on isolated rat pancreatic acinar cells as to the ultrastructure, cytosolic Ca2+ concentration and energy metabolism.

METHODS

Acinar cells were exposed to an oxygen radical-generating system consisting of xanthine oxidase, hypoxanthine and chelated iron ions. Cell injury was assessed by LDH release and electron microscopy. Cytosolic Ca2+ levels and mitochondrial membrane potential were determined by flow cytometry; adenine nucleotide concentrations by HPLC. Mitochondrial dehydrogenase activity was measured by spectrophotometric assay.

RESULTS

Oxygen radicals damaged the plasma membrane as shown by a 6-fold LDH increase in the incubation medium within 180 min. At the ultrastructural level, mitochondria were the most susceptible to oxidative stress. In correlation to the pronounced mitochondrial damage, the mitochondrial dehydrogenase activity declined by 70%, whereas the mitochondrial membrane potential was enhanced by 27% after 120 min. Together this may cause the 85% decrease in the ATP concentration and the corresponding increase in ADP/AMP observed in parallel. In addition, an immediate 26% increase in cytosolic Ca2+ was found, a change which could be inhibited by BAPTA, reducing cellular damage.

CONCLUSION

Cytosolic Ca2+ synergizes with oxygen radicals causing alterations of the ultrastructure and energy metabolism of acinar cells which might contribute to the cellular changes found in early stages of acute pancreatitis.

Influence of curcumin on cyclosporin-induced reduction of biliary bilirubin and cholesterol excretion and on biliary excretion of cyclosporin and its metabolites

We investigated the ability of curcumin, which can be extracted from different Curcuma species, to prevent cyclosporin-induced reduction of biliary bilirubin and cholesterol excretion, and its influence on biliary excretion of cyclosporin (CS) and its metabolites in the bile fistula model in rats. I.v. injection of curcumin (25 and 50 mg/kg) after 30 min increased dose-dependently basal bile flow (30 microliters/kg/min) up to 200%, biliary bilirubin excretion (3000 pmol/kg/min) up to 150%, and biliary cholesterol excretion (22 nmol/kg/min) up to 113%. CS (30 mg/kg) reduced bile flow to 66% and biliary excretion of bilirubin and of cholesterol to 33% of the basal value 30 min after i.v. injection. I.v. administration of curcumin (25 and 50 mg/kg) 30 min after CS increased bile flow dose dependently again to 130% for 1 hour and biliary excretion of cholesterol and of bilirubin to 100% of the basal value for 30 and 150 min, respectively. Injection of curcumin 15 min before CS prevented the CS-induced drop of bile flow at 50 mg/kg and reduction of biliary bilirubin excretion already at 25 mg/kg until the end of the experiment (180 min). The CS-induced reduction of biliary cholesterol excretion, however, was not prevented by curcumin. Finally, the biliary excretions of CS (1200 ng/kg/min) and its metabolites (1200 ng/kg/min) were slightly reduced by curcumin at a dose of 50 mg/kg (to 83% of the initial values). The clinical importance of these controversial effects remains to be shown.

[Technical safety aspects of carving equipment]

In particular carving ski with additional plates (lifters) must be mounted with special ski brakes to avoid injuries which can develop from carving ski which not have been slowed down. A matrix gives information to the sports shop owners which products can be combined together. The danger of injury of the wrist can be reduced by gloves with integrated protectors.

Serum zinc levels and goitre epidemiology in Germany

Zinc is an essential element involved in many basic biochemical reactions. Animal experiments and clinical data support the hypothesis that in the presence of inadequate iodine supply zinc deficiency may be a stimulus for the development of goitre. Within the framework of a study to record goitre prevalence and iodine supply of Germany we determined the serum zinc levels in 5932 clinically healthy persons. The mean value was 13.1 +/- 1.75 mumol/l. There were no differences neither in age, in sex nor in regional distribution. Furthermore there were no correlations between serum zinc level, thyroid volume and urinary iodide excretion. Only 1% of all cases had low zinc levels (< 10 mumol/l). Older people (> 40 years) with lowered serum zinc levels showed significantly larger thyroids. We conclude that there is no relevant undersupply of zinc and therefore the trace element is not involved in the goitre endemy of Germany.

[Determination of alanine aminopeptidase and lactate dehydrogenase in the urine as a control over the patient's course after kidney transplantation]

In 42 patients the determination of alanine aminopeptidase and lactate dehydrogenase in the urine was performed after transplantation of a kidney. In the evaluation of the enzyme activities it was referred to the clinically made rejection diagnosis as well as to the increase of the serum creatinine. We found out that with regard to the clinically made rejection diagnosis the alanine aminopeptidase in 56% and the lactate dehydrogenase in 55% of the cases showed an increase before the beginning of the rejection therapy. Before the corresponding increase of the serum creatinine we could establish an increase of the enzyme activity in the alanine aminopeptidase in 45% and in the lactate dehydrogenase in 65% of the cases. For a better interpretation of the urinary enzyme activities during the rejection crises the average activities of the enzymes immediately after the dismissal of the patients as well as three months, six months and one year after the transplantation are cited. From our investigation results that the daily determination of alanine aminopeptidase and lactate dehydrogenase in the urine is suited, taking into consideration other possible influence factors on the enzyme activity as well as other parameters, to support the diagnostics in finding the rejection after the transplantation of a kidney.