Which organic acids does hemofiltrate contain in the presence of acute renal failure?

It is not generally possible to measure most organic acids in the serum of critically ill patients, due to rapid metabolism and methodological problems. Only the regular measurement of lactic acid and the arterial ketone body ratio (acetoacetate/beta-hydroxybutyrate, AKBR) have been introduced in clinical practice, but these parameters can represent only a part of the disturbed metabolism. In pediatric patients, a chromatographical urine analysis has been established for detection of inborn errors of metabolism, which allows the determination of more than 50 organic acids simultaneously (gas chromatographic (GC) analysis in combination with mass spectrometry (MS)]. In continuous treatment of acute renal failure, hemofiltrate is always available, but it contains only low protein concentrations and after the filtration process, metabolism is rapidly stopped. The sieving coefficient of lactic acid is nearly one in hemofiltration. The aim of our study was to compare results of the regular and CG/MS methods in blood and hemofiltrate for lactic acid, and to find other organic acids of possible clinical importance. We investigated serum (lactic acid) and hemofiltrate of 40 critically ill patitens, similar to the urine analysis method for infants. All patients suffered from acute renal failure and were treated by continuous veno-venous hemofiltration (CVVH). The conditions of treatment were standardized (spontaneous ultrafiltration in the first hour), and the material (blood/hemofiltrate) was taken one hour after the beginning of extracorporeal circulation. Statistical methods included correlation analysis, nonparametric ANOVA with Wilcoxon scores (ranks of data), and stepwise discriminant analysis. Regular and GC/MS methods in hemofiltrate showed a good correlation for lactic acid. The best correlation with lactic acid was found for 4-hydroxy-phenyllactic acid (n=20, r=0.866), 2-hydroxy-valeric acid (n=22, r=0.7491) and 2-hydroxybutyric acid (n=32, r=0.5148). Age, sex, diagnosis, and APACHE II score play a subordinate role, but the presence of glyceric and citric acid possibly have prognostic importance [nonparimetric ANOVA with Wilcoxon scores (ranks of data)], as does the combination of 3-hydroxypropionic acid, glyceric acid, and threonic-acid-4-lacton (stepwise discriminant analysis). It can be concluded that in acute renal failure, the measurement of lactic acid and AKBR can reflect only a small part of disturbed metabolism. Hemofiltrate can be a useful medium in describing metabolic processes in critically ill patients with acute renal failure. Some inherited metabolic diseases in infants (phenylketonuria, maple syrup disease) and ketoacidosis show similar metabolic modifications.     

Characterization of Epidemic and Nonepidemic Methicillin-Resistant Staphylococcus aureus Strains in a University Hospital in Northeast Germany

 The aim of this study was to analyze methicillin-resistant Staphylococcus aureus strains isolated during a 1-year period by means of pulsed-field gel electrophoresis, resistance phenotyping and determination of biochemical features. Eight different resistance phenotypes with the predominant resistance type Pen Oxa Cip (penicillin, oxacillin, ciprofloxacin) were observed. None of the strains tested exhibited decreased susceptibility to vancomycin, but two strains were resistant to mupirocin. Genetic relatedness of methicillin-resistant Staphylococcus aureus isolates could be shown for two outbreaks, one of which was caused by a clone with an epidemic potential concerning duration of colonization/infection of patients and dissemination of the strains in the hospital.     

Hypothermic perfusion and cold storage of the dog pancreas

The results of 18-hours of hypothermic pulsatile perfusion and 18-hours of cold storage of canine pancreas are compared. Both methods of preservation yield the same endocrine pancreas function. However preservation of pancreas by perfusion results in considerable oedema of the gland and high enzyme activity in the perfusate. Therefore, cold storage should be used for the preservation of pancreas.     

Transplantation of isolated islets of Langerhans in diabetic dogs. III. Donor selection by mixed lymphocyte reaction and immunosuppressive treatment.

By means of collagenase digestion and the Ficoll gradient separation technique, viable islets of Langerhans were isolated from canine pancreas. These islets were transplanted into the livers of diabetic dogs. Experimental diabetes was induced by subtotal pancreatectomy and two injections of 25 mg streptozotocin/kg body wt. Five recipients received islets from weakly histocompatible donors and were immunosuppressed by administration of azathioprine and anti-thymocyte serum. Diabetes was ameliorated over a period of 1 year. Glucose tolerance test curves and immunoreactive insulin concentrations in the portal and superior vena cava were significantly impaired in comparison to the diabetic control dogs. No signs of portal hypertension or of disturbances of liver function were observed in recipient dogs during the duration of the experiment.     

Further studies on cold adapted variants of human influenza virus A/Krasnodar/101/59 (H2N2) with special reference to genetic stability of attenuation markers.

A previously described cold adapted (ca) attenuated virus, K/25, derived from parent strain A/Krasnodar/101/59 (H2N2), was further modified by 35 additional passages in chick embryos at suboptimal temperature. The virus obtained had retained a distinct ts and ca phenotype and some other markers of attenuation but differed from formerly isolated ca variants by its higher genetic stability connected with an increased growth capacity in chick embryos.     

Two cases of severe sepsis due to <Emphasis Type="Italic">Vibrio vulnificus</Emphasis> wound infection acquired in the Baltic Sea

Two severe cases of Vibrio vulnificus wound infection with secondary septicemia occurred during 1 week in August 2003 on the German island of Usedom in the southwestern Baltic Sea. In both cases, pre-existing wounds were inoculated by wading in contaminated sea water. One of the patients died from septic multiorgan failure. To the best of our knowledge, this is the first fatality due to a V. vulnificus infection to have occurred in Germany. Microbiological analysis revealed high concentrations of V. vulnificus in sea water along the coastline, following a period when water temperature exceeded 20°C for more than 2 weeks.     

Transplantation of isolated islets of Langerhans in diabetic dogs. II. The influence of histocompatibility.

By means of collagenase digestion and the Ficoll gradient separation technique, viable islets of Langerhans could be isolated from dog pancreata. The isolated islets were capable of secreting insulin after glucose stimulation. These islets of Langerhans were transplanted into the livers of diabetic dogs. We transplanted islets isolated from I donor pancreas for 1 kg body wt of the recipients. The dogs were made diabetic by subtotal pancreatectomy (80%) and two injections of 25 mg streptozotocin/kg body wt. In our experiments, we selected donor-recipient pairs by means of the mixed lymphocyte reaction macrophage electrophoretic migration inhibition (MLR-EM) test. In the group with a depression in the MLR-EM test of more than 15% (strong histoincompatibility), the mean survival time of the transplanted dogs was 46 ± 16 days. Another group of recipients with a depression of macrophage migration of less than 8% (weak histocompatibility) had a mean survival time of 135 ± 49 days after intraportal islet transplantation, and the blood glucose values could be normalized in this group for a period of 70 days. We found significant differences between both the groups in the glucose tolerance tests and in the IRI concentrations in the portal vein and in the vena cava superior. In the recipients, which received weakly histoincompatible islets, the IRI concentration in the superior vena cava was 64% of the normal value in the vena cava superior 4 weeks after intrahepatic islet transplantation. By means of the MLR-EM test, we were able to correlate inhibition with signs of rejection of the transplanted islets. Our experiments demonstrated that an allogeneic islet transplantation in diabetic dogs across a weakly histocompatible barrier can improve the results in comparison to the islet transplantation across a strongly histocompatible barrier. However, this typing maneuver alone is not able to prevent the islet rejection.     

Serum selenium levels and blood glutathione peroxidase activities in vitiligo

It has recently been shown that patients with vitiligo can accumulate epidermal hydrogen peroxide (H2O2) in association with low catalase levels. This study examined serum selenium levels and blood glutathione peroxidase activities in 61 patients and controls. The results showed high serum selenium levels in 56% of the patients. As at least one isoform of glutathione peroxidase requires selenium for its activity, enzyme activities were also evaluated. The overall results were not significantly different compared with controls, but further age-related analysis of the data indicated significantly lower activities in patients up to 46 years. As glutathione peroxidase can also efficiently degrade H2O2, the results of this study could indicate an additional impaired H2O2 metabolism in vitiligo.