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K Failing

Publications and source records attributed to K Failing.

At least 73 records · Page 4Linked to original sources
PubMed1995

Neutralizing antibodies against Shiga-like toxins from Escherichia coli in colostra and sera of cattle.

Previous or present infection with Shiga-like toxin producing E. coli (SLTEC) was detected by an indirect neutralization assay of antibody titer. Bovine colostra and sera blocked the cytotoxic effects of Shiga-like toxin on Vero cell monolayers. SLT neutralizing antibodies were present in 84.0% (189/225) of the colostrum samples from randomly chosen cows in Bavaria, Germany. While all of the colostra with neutralizing activity reacted with SLT-I, only 14.7% neutralized both SLT-I and -II. Approximately 93.0% (37/40) of sera from heifers had SLT neutralizing activity. To quantify the neutralizing antibodies, colostra were tested in the Vero cell assay for their capability to reduce the 50% cytotoxic dose (CD50) of SLT standards, where the neutralizing units/ml (nu/ml) equal the log10 of CD50 reduction. Almost half of reactive colostra (48.7%) reduced the CD50 of the SLT-I standard by 10(4) to 10(5) (4-5 nu/ml). Higher reactivity (5-7 nu/ml) was found in 46.5% of positive colostra. The remaining colostra samples had over 7 nu/ml. To determine if the colostra were blocking receptors for SLT on Vero cells, cells were preincubated with colostra, and SLT was later added. No neutralizing activity was detected, indicating the reactivity of colostra was directed against SLT. When the colostra were subjected to ammonium sulphate precipitation and DEAE anion exchange chromatography, high levels of neutralizing activity were found in the IgG1 containing fractions. Colostrum fractions were tested for SLT-I binding antibodies in a capture ELISA, based on the binding of SLT-I to the toxin receptor analogue P1-glycoprotein. Only fractions from colostra with over 5 nu/ml were reactive in this assay, indicating the ELISA was less sensitive than the Vero cell assay. The results support the theory that SLTEC exposure of cows in Germany is more widespread than expected from epidemiological studies based on bacterial isolation. This possibly indicates a higher risk of human SLTEC infection via beef and milk products.

Animals↗
PubMed1995

In vitro antimicrobial susceptibility testing of Borrelia burgdorferi: influence of test conditions on minimal inhibitory concentration (MIC) values.

A broth microdilution assay was performed to determine the minimal inhibitory concentrations (MICs) of 25 antimicrobial agents for two strains of Borrelia (B.) burgdorferi sensu lato and one strain of B. hermsii. The method comprised BSK II medium lacking gelatin and an incubation period of 72 hours. To investigate the influence of reading mode and density of inoculum on MIC values, microscopical as well as macroscopical MIC reading was performed using standardized final inocula of 10(6) and 10(7) borreliae/ml. Data were processed by two-way analysis of variance. In the microdilution assay, MIC values were significantly influenced either by the inoculum density or reading mode. However, using clearly defined criteria for macroscopical endpoint determination, MICs from macroscopical and microscopical reading were found to be in close agreement. B. burgdorferi sensu lato strains tested were highly susceptible to azithromycin, erythromycin, mezlocillin, piperacillin as well as ceftriaxone, with MICs ranging from < or = 0.016 to 0.125 microgram/ml. B. hermsii was highly susceptible to azithromycin and erythromycin. In comparison to B. hermsii, the beta-lactam antibiotics revealed a significantly higher activity and gentamicin, ofloxacin, and rifampin revealed a significantly lower activity against B. burgdorferi sensu lato strains. To further investigate interactions between BSK II medium, incubation time, and antibiotic efficacy, an agar diffusion bioassay was performed. Out of seven antibiotics tested, the activities of mezlocillin, penicillin G, and piperacillin were significantly influenced by BSK II medium and incubation period and showed a marked decrease of on average 84.0% within 72 hours of incubation.

Anti-Bacterial Agents↗
PubMed1995

Mechanisms of intestinal phosphate transport in small ruminants.

In order to study the localization and mechanisms of intestinal phosphate transport in sheep and goats, unidirectional inorganic phosphate (Pi) flux rates across isolated stripped epithelial tissues were measured in vitro by applying the Ussing-chamber technique. In the first experiment the tissues were obtained from animals which had been kept on an adequate dietary P supply. In the second experiment the animals had either been kept on an adequate Ca and P supply or were Ca- and/or P-depleted. Significant net Pi absorption was measured in all segments of the small intestine and in the proximal colon of sheep and in the duodenum and jejunum of goats. Since the experiments were carried out in the absence of any electrochemical gradient, this clearly indicates the presence of active mechanisms for Pi transport in the intestinal tract of small ruminants. In sheep jejunum, reduction of mucosal Na concentration to 1.8 mM or serosal application of ouabain (0.1 mM) resulted in significant decreases of net Pi absorption of the same order of magnitude, indicating that about 65% of active Pi transport in sheep jejunum is mediated by a Na-dependent active transport mechanism. The mechanism for the remaining Na(+)-independent active Pi transport has not yet been identified. Dietary P depletion caused hypophosphataemia and induced a significant stimulation of net Pi absorption in goat duodenum and jejunum. This increase was independent of dietary Ca supply and was not associated with increased plasma calcitriol concentrations. This suggests substantial differences in hormonal regulation of Pi transport in small ruminants in comparison with single-stomached species.

Animals↗
PubMed1995

Binding properties of goat intestinal vitamin D receptors as affected by dietary calcium and/or phosphorus depletion.

The binding capacity (Bmax) and the affinity (Kd) of the intestinal vitamin D receptor (VDR) have been studied using mucosa preparations from the duodenum, jejunum and proximal colon of male growing goats which had been kept in a two-factorial (2 x 2) trial on Ca and/or P deficient diets for 9 weeks. This treatment resulted in significant changes of different parameters of Ca and P homeostasis. Irrespective from the level of Ca intake, P depletion caused significant hypophosphatemia with corresponding hypercalcemia. In both Ca depleted groups the calcitriol concentrations in plasma significantly increased by more than 100% in comparison with normal Ca supply. No changes were recorded for plasma calcitriol concentrations in response to P depletion with an adequate Ca supply. Plasma PTH levels were only increased significantly in Ca depletion with adequate P supply. Irrespective of different feeding regimens, the highest Bmax values were found in the jejunum. In all intestinal segments tested, the Bmax values were significantly decreased by P depletion as compared with an adequate P supply. No effects on the Bmax of VDR were observed in response to changes of Ca supply. The Kd values of the VDR were neither affected by different intestinal localizations nor by Ca and/or P depletion. From the present results, it has to be concluded that the physiological relevance of VDR down-regulation may not be related to P homeostasis rather than to Ca homeostasis by minimizing the hypercalcemia induced by P depletion.

Animals↗
PubMed1995

[The significance of FeLV infection for diseases in necropsied cats].

Persistent FeLV infection was demonstrated in more than 3000 necropsied cats by an immunohistological method. The findings were associated with the diagnoses established by means of post-mortem examination, histopathological, bacteriological, virological, and parasitological investigations. Statistically significant differences between FeLV-positive and FeLV-negative cats in the relative risk for certain lesions could be demonstrated for the first time. As a consequence, the importance of FeLV infection for the development of certain lesions in cats is to be seen under new aspects for some diagnoses. The relative risk for development of anemia, e.g., is only slightly increased in FeLV-positive animals whereas the relative risk for focal myocardial necrosis and coccidiosis is elevated tremendously in these cats. The relative risk for some lesions and diagnoses is much higher in FeLV-negative cats than in FeLV-positive animals. This is true, e.g., for myocardiopathy and hemorrhagic cystitis.

Animals↗
PubMed1994

Polychlorinated biphenyl congeners in foxes in Germany from 1983 to 1991.

Red foxes served as a biological indicator for the temporal development of environmental contamination with polychlorinated biphenyls (PCB). The concentration of PCB congeners nos. 28, 49, 52, 101, 138, 153, and 180 were analyzed in the body fat of 80 foxes (Canis vulpes) from Germany. The samples were from animals that had been submitted for examination in 1983, 1987, and 1991. Throughout this time period, a reduction was seen in the concentration of the highly chlorinated biphenyls 138, 153, and 180, whereas the concentration of the low-chlorinated congeners PCB nos. 28, 49, and 52 increased. No change in contamination with congener 101 was observed. These results show a trend toward reduction of environmental contamination with highly-chlorinated biphenyls since 1983, while contamination with low-chlorinated congeners is apparently increasing. An interesting observation is the disproportionately higher amount of 2,2',3,4,4',5,5'-hepatachlorobiphenyl (PCB 180) over that of 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) in body-fat samples from all foxes analyzed. This phenomenon was also observed in 10 dogs examined as controls. Based on evidence from other authors of experimental toxicological studies on beagles, it appears that the fox possesses a similar cytochrome P-450 isoenzyme that can degrade 2,4,5-trichloro-substituted aromatic compounds. As a consequence, in canines, PCB 180 which is additionally meta-chloro substituted is accumulated to a greater degree than is PCB 153.

Adipose Tissue↗
PubMed1994

[The effect of herd and animal factors on the detection of complement-binding antibodies against Coxiella burnetii in cattle].

To determine the prevalence of bovine Coxiella (C.) burnetii infections in Northern Lower Saxony, blood serum obtained from a total of 2160 cattle was examined for antibodies against C. burnetii using the complement fixation test (CFT). From 500 randomly sampled cattle, 38 (7.6%) were seropositive. In 383 cows out of 33 dairy herds with the history of reproductive problems a significantly higher prevalence of C. burnetii specific antibodies was found than in 665 cows out of 39 herds without reproductive problems (19.3% vs. 9.6%). In both groups, mean CFT titer increased significantly with the degree of the within herd prevalence. Furthermore, in dairy herds with fertility problems the within herd prevalence was significantly higher than in dairy herds not experiencing infertility (24.3% vs. 11.2%). A relationship between serological evidence of C. burnetii infection and incidence of reproductive disorders observed in lowered fertility herds was not found. Statistical analysis of CFT results of 668 cows allocated in groups according to month of gestation, month prior insemination, and month postpartum revealed that the percentage of seropositives as well as CFT titers rise significantly in the 1st month of gestation and after a sharp decline in the 4th month increase a second time in the 7th month of gestation. Sera from 612 bulls aged six months to ten years yielded 5.2% seropositives. The most positives (87.5%) were found in bulls aged up to two and a half year. After a six month period, 428 bulls were retested. Specific antibodies were found in eight (27.6%) of 29 formerly seropositives. Seroconversion was not detected in any of 399 formerly seronegative bulls.

Animals↗
PubMed1992

Ovarian and pituitary function in dogs after hysterectomy.

In studies of five hysterectomized and five control dogs, hysterectomy shortened the anoestrous interval (96.6 +/- 28.0 versus 149.4 +/- 50.9 days, P < 0.05). No differences in hormone concentrations (progesterone, oestradiol, prolactin and growth hormone) were observed between the control and hysterectomized dogs except for a brief fall in progesterone concentrations over 8 days immediately after surgery, between days 35 and 40 after onset of pro-oestrous bleeding; only these animals developed symptoms of overt pseudopregnancy. It is concluded that, in dogs, luteal regression occurs independently of a uterine luteolysin, but that the uterus may play a role in control of duration of anoestrus. Pseudopregnancy seems to be initiated by a fall in progesterone concentrations rather than by other hormonal changes.

Analysis of Variance↗
PubMed1992

[Use of anthelmintics for nematode control in sheep in West Germany: results of a survey].

A survey by questionnaires was performed on 543 (0.9% of all) sheep flocks in western Germany in 1988/89 to obtain informations about deworming practices against gastrointestinal nematodes. The major informations are: Anthelmintic treatments were associated with the reproductive status of ewes and the breeding of lambs in most of the flocks. They were performed at an epidemiologically appropriate time in many cases but were not accompanied by essential management practices. (Pro)benzimidazole compounds were the anthelmintics most frequently used by more than 95% of the farmers; 22% and 13% of the farmers additionally or exclusively administered levamisole/pyrantel and ivermectin, respectively. On average, treatment of ewes and lambs against nematodes was performed 2.5 times and 2.8 times a year, respectively. The mean frequency of deworming differed regionally and was generally greater in pedigree breeding flocks than in commercial breeding flocks; it was significantly affected by the husbandry system, the number of ewes per flock, the size of available pasture and the class of anthelmintics employed. The results of this survey revealed that many German sheep farmers obviously lack an awareness of the rationale of preventive and economic control practices against gastrointestinal nematodes.

Animals↗
PubMed1990

[Polychlorinated biphenyls (PCB) in fish from hatcheries and clarifying ponds].

The concentrations of six selected single polychlorinated biphenyl (PCB) congeners, for which legal tolerance levels became valid in 1988, and the congener no. 49 (2,2',4,5'-tetrachlorobiphenyl) were determined in the muscle tissue of 58 fishes from fish hatcheries and in 17 fishes from settle ponds. The fish were taken from flowing waters in the years 1986 and 1987. High and low chlorinated biphenyls were present in each sample, but the concentration of the low chlorinated biphenyls was distinctly lower than that of the higher chlorinated ones. Nevertheless these results demonstrate the intake of components of low chlorinated technical PCB mixtures in the environment and food chains. Compared with the investigations carried out in 1980/81 in fishes from fish hatcheries, a decrease of PCB contamination in the muscle tissues with regard to the technical mixture Clophen A 60 was observed. This is in accordance with the results our team obtained a short time previously in muscle tissue from foxes and in food-stuffs. The concentration of all PCB congeners determined in the muscle tissue from fish of settle ponds was significantly higher than in the tissue from fish taken from hatcheries. Thus, the PCB content depends on the PCB load in different environments. Therefore, fishes can be useful as bioindicators for the intake of low and high chlorinated PCB congeners in aquatic ecosystems.

Animals↗
PubMed1989

A dose-dependent effect of recombinant erythropoietin on the reticulocyte population of rats.

The effect of human recombinant erythropoietin (rEPO) on the reticulocyte count and the reticulocyte maturation distribution in rats was measured with an automatic reticulocyte analysis system (AURAS). The strongest reaction was found on the third day after a single application of rEPO with respect to reticulocyte count, maturation distribution, and the count of immature reticulocytes. At this time these parameters show a distinct dose dependency. The results indicate a possible basis for a simple rEPO bioassay using normocytemic rats.

Animals↗
PubMed1988

[The effectiveness of the combined treatment of thrombocytic hemorrhagic diathesis of dogs with prednisolone and blood transfusion in the model of an aspirin-produced thrombocytopathy].

The administration of 20 mg/kg of acetylsalicylic acid in 18 clinically healthy dogs resulted in a thrombocytopathy with lengthened capillary bleeding time and irreversible aggregation inhibition. Through the set up of individual dilution series, one could conclude the proportional percentage of aggregation functional transfused thrombocytes. The capillary bleeding time was shortened after the intravenous injection of prednisolone (5 mg/kg) without measurable influence on the thrombocytes. Compared to the singular use of cortisone or blood transfusion alone, the effect on capillary bleeding time became magnified when one combined transfusion and corticosteroids. The fresh blood conserves (12 hours) were, with respect to the haemostyptical properties, superior to blood stored for 5 days. The component of aggregation-functional thrombocytes was, due to the prophylactic cortisone application prior to transfusion, not increased.

Animals↗
PubMed1987

Cytotoxic protein from Pseudomonas aeruginosa: formation of hydrophilic pores in Ehrlich ascites tumor cells and effect on cell viability.

Increased plasma membrane permeability induced by a purified cytotoxic protein from Pseudomonas aeruginosa was studied using mouse Ehrlich ascites tumor cells in incubation medium containing an osmotic stabilizer. In the presence of serum albumin, 40 nM of the cytotoxin was required for cationic imbalance of 2.7 X 10(7) cells per ml at pH 7.4. The rate of passive flux of water-soluble markers with a molecular radius range between 0.3 and 4 nm was used to calculate the size of functional transmembrane pores. Within a short time of intoxication pores of 1 nm in radius were formed. Their stability is inferred from the constant rate of leakage of the most restricted marker during intoxication (60-90 min). The cytotoxin-induced plasma membrane damage led to loss of essential low molecular weight substances and was associated with a decrease of tumor propagation rate in mice. Regression analysis of these functional parameters indicate the reversibility of plasma membrane disorganization up to complete breakdown of the Na+/K+ gradient. The cell can even tolerate partial loss of larger cytosolic compounds under conditions of limited intoxication.

Animals↗
PubMed1981

[A contribution to stepless antibody determination by the "enzyme linked immunosorbent assay" (ELISA) (author's transl)].

A simple method for the mathematical calculation of ELISA results is described. Using the formula (formula: see text) (Eu, En, Ep = extinction values of the unknown serum, the negative, and positive standard serum, respectively) an index value Iu is calculated for the testserum, whereby the optical density of the testserum is put in relation to the optical density of a negative and positive standardserum. Using three different ELISA test systems, the Iu values of a number of human, bovine and rabbit testsera were relatively uniform and reproducible in repeated investigations. A statistically calculated tolerance limit for the index values of negative sera can be introduced into the formula described, thus facilitating the decision "negative" or "positive" for unknown sera.

Animals↗
PubMedDate not supplied

Tissue penetration of sparfloxacin in a rat model of experimental Escherichia coli epididymitis.

The epididymal, testicular, and prostatic tissue penetration of sparfloxacin, a new quinolone, was assessed in a rat model of acute epididymitis. Seventy-two hours after injection of 0.1 ml (10(6) cfu/ml) of an Escherichia coli suspension into the right epididymis via the right ductus deferens, a single oral dose of sparfloxacin 50 mg/kg body weight was administered. One, 2, 4, 8, 12, and 24 h after administration the animals were sacrificed and the sparfloxacin concentrations and "areas under the curve" (AUC0-24) in both epididymides, both testes, the prostate gland and in the serum were measured by bioassay. The highest mean AUC0-24 was found in the prostate gland, followed by left epididymis, right epididymis, serum, right testis, and left testis (190, 79, 60, 28, 12, and 9 mg/kg x h, respectively). Though there was no statistically significant difference in the sparfloxacin concentration of both epididymides (p = 0.09), the mean AUC0-24 was significantly higher in the non-infected left epididymis (p < 0.0001). The AUC0-24 and sparfloxacin concentrations of the right infected epididymis were significantly higher than those observed in the serum (p < 0.0001). In both testes, the AUC0-24 and sparfloxacin concentrations were lower than in the serum (p < 0.0001), however, the concentration exceeded the MIC tenfold for approximately 20 h. It is concluded that the pharmacokinetic properties of sparfloxacin (good in vitro activity, high penetration into the prostate gland, testes, infected and non-infected epididymides) make this drug a recommendable choice for the initial treatment of acute epididymitis caused by E. coli.

Animals↗