Biomedical subjects
Publications and source records attributed to R Krieger.
The status quo of the Order on Animal Welfare in farmed Animals is described. After being amended in February 2002, it provides, beside a general part, special chapters on the keeping of calves and of laying hens. Further special chapters on the keeping of pigs and of fur animals are to be included in the near future.
Pseudomonas aeruginosa forms most of its heme under anaerobic denitrifying conditions. To study the regulation of the hemA gene, which codes for the first enzyme of heme biosynthesis in P. aeruginosa, a lacZ reporter gene fusion was constructed. Expression of lacZ under the control of the hemA promoter was found to be increased by 2.8-fold under anaerobic conditions in the presence of the alternative electron acceptor nitrate, relative to the level observed under aerobic growth conditions. Anaerobic fermentative growth or the presence of nitrite did not affect the lacZ expression. The genes encoding the oxygen sensor protein Anr, the redox regulator Dnr, the nitrate regulator NarL and the DNA-bending Integration Host Factor (IHF) are all required for the cooperative anaerobic induction of the hemA promoter hemAp (1). Potential binding sites for these regulatory proteins were identified by site-directed mutagenesis of the promoter fused to the reporter gene. The mode of regulation of P. aeruginosa hemA differs significantly from that described for the hemA gene of Escherichia coli K-12.
Council Directive 91/630/EEC of 19 November 1991 laying down minimum standards for the protection of pigs has been amended in 2001. The following text provides a survey of the progress of the discussion at European level and of the options for transposing into national law.
Acetylene hydratase of Pelobacter acetylenicus is a tungsten iron-sulfur protein involved in the fermentation of acetylene to ethanol and acetate. Expression of the enzyme was increased 10-fold by feeding a 50-L batch culture continuously with 104 Pa acetylene at pH 6.8-7.0. Acetylene hydratase was purified to homogeneity by a three-step procedure in either the absence or presence of dioxygen. The enzyme was a monomer with a molecular mass of 73 kDa (SDS/PAGE) or 83 kDa (matrix-assisted laser-desorption ionization MS) and contained 0.5 +/- 0.1 W (inductively coupled plasma/MS) and 1.3 +/- 0.1 molybdopterin-guanine dinucleotide per mol. Selenium was absent. EPR spectra (enzyme as isolated, under air) showed a signal typical of a [3Fe-4S] cluster with gav = 2.01, at 10 K. In enzyme prepared under N2/H2, this signal was absent and reaction with dithionite led to a rhombic signal with gz = 2.048, gy = 1.939 and gx = 1.920 indicative of a low-potential ferredoxin-type [4Fe-4S] cluster. Upon oxidation with hexacyanoferrate(III), a new signal appeared with gx = 2.007, gy = 2.019 and gz = 2.048 (gav = 2.022), which disappeared after further oxidation. The signal was still visible at 150 K and was tentatively assigned to a W(V) center. The iron-sulfur center of acetylene hydratase (prepared under N2/H2) gave a midpoint redox potential of -410 +/- 20 mV in a spectrophotometric titration with dithionite. Enzyme activity depended on the redox potential of the solution, with 50% of maximum activity at -340 +/- 20 mV. The presence of a pterin-guanine dinucleotide cofactor differentiates acetylene hydratase from the aldehyde ferredoxin oxidoreductase-type enzymes which have a pterin mononucleotide cofactor.
Ammonia emissions from animal farming have negative effects inside and outside of animal housings. Numerous feed or slurry additives are offered to reduce the ammonia emissions from pig keeping. Investigations were carried out to test the effectiveness of a clinoptilotite-containing feed additive named "Klinofeed" on practical farms and in laboratory experiments. Some effects of ammonium retention were seen in the laboratory tests, which also revealed informations on the absorption mechanisms of ammonium ions. The field experiments didn't show any ammonia reducing effect of the additive. It is recommended to develop a standardized procedure of testing the effectivity and usefulness of feed and slurry additives which are manufactured and sold for ammonia reduction purposes. The presented experiment could be a first basis for such a test procedure.
Peach harvest workers were evaluated for exposure to azinphosmethyl residues by measuring foliar residues, urinary alkylphosphate metabolites, butyrylcholinesterase (BChE), acetylcholinesterase (AChE), and dermal residues using clothing and skin washes. Workers entered orchards 51 days after application and worked in treated fields for 10 of the next 17 days. Dislodgeable foliar residues ranged from 0.82 to 1.72 microg/cm2 and did not change significantly over the study period. Combined mean dermal exposure for the 3 consecutive monitoring days was 32 mg and ranged from 17.9 to 60.5 mg. Overall mean excretion levels for the 5 monitoring days were 1.7 mg dimethylphosphate and 1.9 mg dimethlythiophosphate. There was no significant difference in BChE between the exposed harvesters and minimally exposed sorters. The exposed group had significantly lower AChE values than the sorters for 2 post-exposure blood draws by three testing methods, while no significant difference was found for the pre-exposure blood draw. The AChE values for the post-exposure blood samples for the exposed workers decreased significantly about 10-20% over the 3-week exposure period but increased or remained constant for the sorters. Urinary metabolite excretion increased with continuous exposure and was inversely correlated with both AChE and BChE but was not correlated with dermal exposure measurements. High correlations were generally observed between AChE measurements taken in the field using a new spectrophotometric kit and laboratory AChE measurements.
Structured interviews were administered to 22 children, ranging in age from 6 to 10 years old, who did not disclose long-term sexual abuse by an auxiliary school employee, despite having been exposed to a school-based child sexual abuse prevention program. The results are presented in the context of a review of existing literature on school-based child sexual abuse prevention programs. Results point to the ineffectiveness of brief, single presentation, prevention efforts not geared to specific developmental levels of the audience, the need to explore the impact of the variable of group versus individual victimization on disclosure, and the need for further study of sexually victimized children who received prevention programming with the addition of a control group sample.
Left ventriculography has become the single most important procedure in the evaluation of cardiac function. This study reevaluated the refinements of catheter and power injector technology to assess recommendations of past years and establish new principles for optimum ventriculography. Ventriculograms from 102 patients undergoing left heart catheterization and coronary arteriography for coronary, valvular, and myocardial heart disease served as the test sample. Three styles of #7F high-flow 110-cm pigtail catheters were utilized. One had 12 sideholes while the other two had six sideholes positioned nearer the base of the curl. Analysis of ventriculographic quality of each angiogram was performed by three of the authors independently and subsequently together. Five variables were analyzed for their effect on the diagnostic quality of the angiogram: 6-hole catheters, 12-hole catheters, volume of contrast, flow rate, and location of injection. Once these analyses were complete, the effect of combinations of these variables was tested to determine their effect on angiographic quality. The first combination included contrast volume and flow rate. The second combination compared contrast volume and flow rate when utilized with 6- or 12-hole catheters. The third combination tested the 6- and 12-hole catheters in the apex or inflow locations. A multivariate contingency analysis was used to define relationships between the variables and the quality of the angiogram obtained. As independent variables, catheter style, volume of contrast, flow rate, and location of injection did not influence angiographic quality. However, the apex as a location of injection was the single most consistently important determinant of ventricular angiographic quality.(ABSTRACT TRUNCATED AT 250 WORDS)
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A method is described for rapid determination of protein-bound carbohydrates in human lipoproteins. The method is based on a successive precipitation of lipoproteins with sodium phosphotungstate and magnesium chloride. After purification of the separated lipoproteins by a twofold reprecipitation, a colorimetric determination of hexoses, hexosamines and N-acetylneuraminic acid (sialic acid) is performed. The coefficients of variation in the series are between 3.2% and 7.3%. The results for lipoprotein-bound carbohydrates after precipitation are compared with the corresponding values after separation by ultracentrifugation. The concentrations of hexoses, hexosamines and N-acetylneuraminic acid in the 3 lipoprotein classes VLDL, LDL and HDL of control persons are reported.
a micromethod is described for the determination of free or glycoprotein-bound N-acetylneuraminic acid (NANA) on the basis of oxidation with periodic acid and reaction with thiobarbiturate. When using athe Eppendorf microliter system the method is easy to perform, the lowest level of sensitivity being 0.2 nmoles NANA in the incubation mixture. The intraassay precision comprises 3.0% CV, the interassay precision 4.3% CV. The accuracy of the results obtained by this micromethod was proved by comparative experiments with the macromethod according to Warren ((1959), J. Biol. Chem. 234, 1971-1979) using sialyllactose, transferrin and fibrinogen as reference materials.
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A specific, sensitive, and reliable radioimmunoassay for serum-conjugated deoxycholic acid has been developed with antiserum obtained after immunization of rabbits with deoxycholic acid--bovine serum albumin conjugate. The displacement curve of glyco [3H] deoxycholic acid was linear on a logit-log plot from 7.5 to 320 pmol of unlabeled glycodeoxycholic acid. At 50% displacement of bound label, the cross-reactivity of taurodeoxycholic acid was 100%, deoxycholic acid 30%, taurocholic acid 3%, and glycocholic acid 2%. No cross-reactivity was observed with free cholic acid, conjugated or free chenodeoxycholic acids and conjugated or free lithocholic acids. Fasting serum-conjugated deoxycholic acid concentrations in 10 healthy volunteers ranged from 0.18 to 0.92 mumol/1. Over a period of 5 hours following 0.5 g oral cholate administration the serum-conjugated deoxycholic acid concentration did not change in 5 fasting healthy persons, whereas an initial increase of serum cholic acid was observed.
A radioimmunoassay for serum conjugated cholic acid is described using antiserum obtained five weeks after immunization of rabbits with cholic acid bovine serum albumin conjugate. Prior to the radioimmunoassay, extraction of bile acids was performed with Amberlite XAD-2. The displacement curve of glyco[3H]cholic acid was linear on a logit-log plot from 5 to 80 pmol of unlabelled glycocholic acid. Values for 8 normal fasting subjects ranged from 0.18 to 1.25 mumol/1. In 31 fasting subjects with or without liver disease serum values of conjugated cholic acid are related to serum bilirubin. Endoscopic retrograde cholangiopancreatography may influence serum levels of conjugated cholic acid.
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Serious arrhythmias are accepted to be the main cause of sudden death in acute coronary artery disease (CAD). The purpose of this study was to evaluate the frequency and type of cardiac arrhythmias in patients with chronic CAD. 67 patients with suspected chronic CAD, documented by history and/or Ecg-changes, were investigated by means of a dynamic Ecg (Holter Avionics) with an average of 11 hours monitoring. On the basis of concomitant ST-segment depressions the patients were divided into 3 groups (A: greater than 0.1mV; B: 0.05-0.09mV; C: less than 0.05mV). The frequency of serious arrhythmias increased significantly with a greater degree of ST-segment depression. Serious arrhythmias were observed in 54% in group A, in 46% in group B, but only in 24% in group C. The frequency of minor arrhythmias such as occasional (less than 12/min atrial or ventricular premature contractions was essentially the same in all 3 groups. In 12 patients more than one serious arrhythmia were documented. Of the serious arrhythmias observed, 94% were tachycardias and/or secondary to increased myocardial irritability and therefore could respond favourably to beta-blocking agents. We believe that arrhythmias in patients with known chronic CAD should be taken seriously and longterm treatment with beta-blockers considered.