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C Bauer

Publications and source records attributed to C Bauer.

At least 55 records · Page 3Linked to original sources
PubMed2002

Characteristics of a flubendazole resistant isolate of Oesophagostomum dentatum from Germany.

Two controlled tests were performed to investigate the benzimidazole resistance of a nodular worm isolate "GIBZ" from a pig breeding farm in Germany. In Trial I, groups of five pigs, artificially infected with Oesophagostomum larvae isolated from that farm were treated with flubendazole at a single dose of 5 mg kg(-1) bodyweight (BW) or remained untreated. In Trial II, three groups of three pigs each infected with larvae after a further laboratory passage of this isolate were treated with flubendazole either at a single dose of 5 mg kg(-1) BW or at a divided dose of 1.5 mg kg(-1) BW daily for 5 consecutive days, or with fenbendazole at a single dose of 5 mg kg(-1) BW, the fourth infected group remained untreated. The respective doses of anthelmintics were mixed with a small amount of feed and administered to individual pigs in both trials. Fecal egg counts before and after treatment and post-mortem worm burdens 7 days after (last) treatment were examined to assess the anthelmintic efficacies. Only infections with Oesophagostomum dentatum were found in both trials. In Trial I, the mean worm count reduction by flubendazole was 30% as compared to the untreated controls. In Trial II, flubendazole administered at a single or divided dose reduced the mean worm burden by 0 and 85%, respectively, whereas fenbendazole was 100% effective. These results establish resistance to flubendazole in the isolate "GIBZ" of O. dentatum. The failure to reveal side resistance to fenbendazole may be explained by that the currently recommended dose rate of this compound is supra-optimal for porcine nodular worms.

Animals↗
PubMed2002

Genetic differences of Ascaridia galli egg output in laying hens following a single dose infection.

Groups of 20-week-old white (Lohmann LSL) and brown (Lohmann Brown) hens were reared under helminth-free conditions and both divided into two subgroups. One subgroup was artificially infected with 250 embryonated Ascaridia galli eggs, the other subgroup were kept as uninfected controls. During the following 12-month laying period individual faecal Ascaridia egg counts (FEC) were performed and bodyweight measured at monthly intervals. Laying performance and egg weights were determined daily. The mean FEC were significantly (P < 0.01) higher in infected white hens than in infected brown hens. The growth rate of the white hens was significantly (P < 0.05) higher in the control group, whereas in brown hens no significant group difference was observed. The laying performances and egg weights did not differ significantly (P > 0.05) between control and infected animals for either line. The estimated repeatabilities for mean log(10) FEC of different samples were reasonably high (0.16-0.54). Heritabilities for mean log(10) FEC were between 0.13 and 0.19 for white hens and between 0.0 and 0.10 for brown hens. Thus, it should be possible to select for A. galli resistance in chickens, which will be of importance for birds kept in alternative and organic farming systems.

Animals↗
PubMed2002

Prevalence of levamisole and benzimidazole resistance in oesophagostomum populations of pig-breeding farms in North Rhine-Westphalia, Germany.

The objective of this cross-sectional study was to estimate the prevalence of anthelmintic resistance in porcine strongylid populations in northern North Rhine-Westphalia. A random, weighted sample of 144 pig-breeding farms, stratified by organisation and herd size, was selected from a total of 706 farms with at least ten sows associated with three breeding organisations. On 61 of all visited farms, no or insufficient strongylid eggs were found in the faecal samples. Eighty-three farms were surveyed for resistance by a larval development test (LDT) using a cut-off concentration of 0.58 microg ml(-1) for levamisole and of 0.0113 microg ml(-1) for thiabendazole. The results indicated resistance to levamisole and benzimidazole in Oesophagostomum spp on one and two farms, respectively. Quantitative LDT showed increased LD50 values of levamisole (0.24 microg ml(-1)) and thiabendazole (0.01-0.015 microg ml(-1)) for these field populations when compared with a drug susceptible laboratory strain of O. dentatum (0.084 microg ml(-1) levamisole; 0.0093 microg ml(-1) thiabendazole). Faecal egg count reduction tests using single standard doses of levamisole and flubendazole corroborated the LDT results. Thus, the prevalence of levamisole and benzimidazole resistance was estimated to be 2-3.5% in sow herds of northern North Rhine-Westphalia. The economic importance of these data is assessed.

Animals↗
PubMed2001

Translation initiation factor eIF-4G is immunogenic, overexpressed, and amplified in patients with squamous cell lung carcinoma.

BACKGROUND: Recently, the authors reported identification and cloning of several novel immunogenic antigens in squamous cell lung carcinoma. Of 14 corresponding genes, 9 mapped in an amplified chromosomal region with the gene for eIF-4G that was amplified most frequently. METHODS: Recombinant eIF-4G was expressed in E. coli and screened with sera from patients with squamous cell carcinoma of the lung and of the head and neck. Protein extracts from squamous cell carcinoma tissues were analyzed for eIF-4G expression by Western blot analysis. Mutation analysis was performed using an automatic DNA sequencer. RESULTS: The authors screened a spectrum of 33 heterologous sera from lung carcinoma patients and detected antibodies against eIF-4G in 5 of these sera (15%). They found no immune response to eIF-4G in 17 sera from squamous cell carcinoma tissues derived from the head and neck. In addition, no antibodies were found to eIF-4G in a group of 17 control sera from individuals without known tumor formation. Sequence analysis of the eIF-4G gave no indication of mutations. To analyze the expression of eIF-4G, a monoclonal antibody was used. Western blot analysis clearly showed overexpression in the tumor tissue compared with the corresponding normal lung tissues. CONCLUSIONS: The translation initiation factor eIF-4G is the first protein in which the gene shows amplification, has increased expression in a human tumor, and induces an immune response in patients. eIF-4G lends itself as a marker for the diagnosis of and possibly as a future therapeutic target in patients with squamous cell lung carcinoma.

Antibody Formation↗
PubMed2001

About the stereoelectronics of the intramolecular addition of allylsilanes to aldehydes.

(Z)-omega-Trimethylsilyl-(omega-2)-alken-1-ols are readily accessible by consecutive superbase metalation and silylation of (omega-1)-alken-1-ols. These versatile intermediates may be oxidized to give the corresponding (Z)-omega-trimethylsilyl-(omega-2)-alkenals which, in the presence of trifluoroacetic acid, can be converted into 2-vinylcycloalkanols such as 2-vinylcyclohexanol (2), isopulegol (4), and bis(2-vinylcyclobutyl) ether (8). The stereochemical outcome of these cyclization reactions suggests the interference of a novel electrodynamic effect.

Journal Article↗
PubMed2001

A unified theory of enzyme kinetics based upon the systematic analysis of the variations of k(cat), K(M), and k(cat)/K(M) and the relevant DeltaG(0 not equal) values-possible implications in chemotherapy and biotechnology.

To elucidate the kinetic properties of critical enzymatic situations that have previously escaped classification, we performed a systematic analysis of all the possible variations of the kinetic constants k(cat,) K(M,) and k(sp) = k(cat)/K(M,) encompassing all aspects of enzymology. The equation gives a total of thirteen theoretically possible cases, comprising the reference case plus 12 different sets of variations, which can be divided into six principal cases and six specular ones. The six relevant cases are examined individually in the context of each of the main chapters of enzymology, i.e. as regards mechanism of action, specificity of substrate and isoenzyme, reversible and irreversible inhibition, and mutation of residues (enzyme evolution and enzyme engineering). Some critical cases where k(sp) does not hold as a specificity index are classified for the first time. Interestingly, the six possible cases correspond to the five known cases of reversible inhibition (competitive, non-competitive, incompetitive, mixed competitive/non-competitive, and mixed incompetitive/non-competitive) plus an additional case of biphasic nature (activation-inhibition), which is crucial for a full understanding of specificity and which leads us to propose some modification to the definition of enzyme specificity. The systematic approach to enzymology outlined herein could find practical applications in various sectors of biotechnology, including chemotherapy.

Binding, Competitive↗
PubMed2001

Effect and repeatability of Ascaridia galli egg output in cockerels following a single low dose infection.

Three groups of caged 20 Tetra-SL cockerels aged 1 day were orally infected with 30, 60 or 125 embryonated Ascaridia galli eggs. After 11, 12 and 13 weeks, faecal egg counts (FECs) were determined. All birds were slaughtered after the last sampling. A group of 25 control birds was sampled and slaughtered in parallel. The gastrointestinal tracts were examined for the presence of adult stages of A. galli. A random sample of 10% was also examined for the presence of immature stages of A. galli. The group with an infection dose of 125 eggs showed the highest average worm burden (p<0.05) and number of females (p<0.05), but the mean establishment rate was the lowest in this group. There was no significant difference in the mean logFEC between the groups. The logFEC per female worm was the highest in the low infection group (p<0.05). The average worm length and weight and the birds body weight were not significantly different among the groups. The estimated repeatabilities for mean logFEC of the different samples were reasonably high (0.55-0.87). This may open a way of genetic selection for A. galli resistance in chickens, which will be of importance for birds kept in alternative and organic farming systems.

Animals↗
PubMed2001

Hyperproliferation and defects in epithelial polarity upon conditional ablation of alpha-catenin in skin.

When surface epithelium was conditionally targeted for ablation of alpha-catenin, hair follicle development was blocked and epidermal morphogenesis was dramatically affected, with defects in adherens junction formation, intercellular adhesion, and epithelial polarity. Differentiation occurred, but epidermis displayed hyperproliferation, suprabasal mitoses, and multinucleated cells. In vitro, alpha-catenin null keratinocytes were poorly contact inhibited and grew rapidly. These differences were not dependent upon intercellular adhesion and were in marked contrast to keratinocytes conditionally null for another essential intercellular adhesion protein, desmoplakin (DP). KO keratinocytes exhibited sustained activation of the Ras-MAPK cascade due to aberrations in growth factor responses. Thus, remarkably, features of precancerous lesions often attributed to defects in cell cycle regulatory genes can be generated by compromising the function of alpha-catenin.

Alleles↗
PubMed2001

CT-integrated robot for interventional procedures: preliminary experiment and computer-human interfaces.

Pre-operative planning and intra-operative computer interfaces for minimally invasive interventions were investigated with an active robot integrated with a CT scanner. To test the robotic system, a biopsy study was performed using a pig. For pre-operative planning, a virtual needle was superimposed on axial slices and multiplanar reformatted views in correlation with the interventional field. The path of the virtual needle was sent to the robot's controller, and the robot's needle gripper moved into a position congruent with the planned path. Intra-operative controls were then used to drive the needle while keeping the interventionalist's hands out of the direct X-ray beam during CT fluoroscopy. After needle insertion, the imaged and virtual needles were shown to be sufficiently congruent.

Animals↗
PubMed2001

Impaired sodium excretion, decreased glomerular filtration rate and elevated blood pressure in endothelin receptor type B deficient rats.

The renal endothelin (ET) system, particularly the ET type B receptor, has been implicated in the regulation of sodium excretion and glomerular filtration rate (GFR). We analyzed kidney morphology and function in a rat strain characterized by complete absence of a functional ETB receptor. Due to Hirschsprung's disease limiting lifetime in these rats, studies were performed in 23-day-old rats. Kidney size and morphology (glomerular and interstitial matrix content, glomerular size and cell density and intrarenal vascular morphology) were normal in ETB-deficient rats. There were also no evidence of altered kidney cell cycle regulation in these rats. GFR was significantly lower, by 72% (P<0.001), in homozygous ETB-deficient rats than in wild-type rats. Fractional sodium excretion was likewise markedly reduced by 84% in homozygous ETB-deficient rats (P<0.001 versus wild-type rats). Treatment with the specific epithelial sodium channel blocker amiloride led to a much higher increase in fractional sodium excretion in ETB-deficient rats (934.2+/-73% in ETB-deficient rats versus 297+/-20% in wild-type rats, expressed as percentage of corresponding placebo treated control; P<0.001). Mean arterial blood pressure was elevated by 7.9 mmHg in homozygous ETB-deficient rats (P<0.05 versus wild-type rats). Our study demonstrates that ETB-deficiency causes early onset kidney dysfunction characterized by a markedly reduced sodium excretion, decreased GFR, and slightly elevated blood pressure. The complete absence of the ETB receptor causes in the kidney--in contrast to the colon--a functional rather than a developmental, neural crest cell dependent disease, since kidney morphology was normal in ETB-deficient rats. The much higher increase in the fractional sodium excretion in ETB-deficient rats after pharmacological blockade of the epithelial sodium channel indicates that the decreased fractional sodium excretion in ETB-deficient rats is most probably due to a lack of the inhibitory property of the ETB receptor on the epithelial sodium channel activity.

Amiloride↗
PubMed2001

Desmoplakin is essential in epidermal sheet formation.

We have generated an epidermis-specific desmoplakin (DP) mouse knockout, and show that epidermal integrity requires DP; mechanical stresses to DP-null skin cause intercellular separations. The number of epidermal desmosomes in DP-null skin is similar to wild type (WT), but they lack keratin filaments, which compromise their function. DP-null keratinocytes have few desmosomes in vitro, and are unable to undergo actin reorganization and membrane sealing during epithelial sheet formation. Adherens junctions are also reduced. In vitro, DP transgene expression rescues these defects. DP is therefore required for assembly of functional desmosomes, maintaining cytoskeletal architecture and reinforcing membrane attachments essential for stable intercellular adhesion.

Adherens Junctions↗
PubMed2001

Prevalence of enteropathogens in suckling and weaned piglets with diarrhoea in southern Germany.

Faecal samples from suckling (n = 205) and weaned piglets (n = 82) with diarrhoea from 24 farms in Southern Germany were examined for shedding of important metazoic parasitic, viral and bacterial pathogens using culture, microscopic and electronmicroscopic methods. Escherichia coli isolates were tested further for the enterotoxin genes est-Ia and elt-I by colony blot hybridization. Isospora suis was diagnosed in 26.9% and Cryptosporidium parvum in 1.4% of the piglets investigated. The proportion of coronavirus-positive animals was 13.4% and 4% were positive for rotavirus. It was found that 17.6% of the animals were infected with enterotoxigenic E. coli (ETEC; 10.1% ETEC-ST-Ia and 8.6% ETEC-LT-I, respectively). The occurrence of the pathogens was significantly associated with the age of the animals examined (P < 0.001). Isospora suis was predominantly isolated from suckling piglets (in the second and third week of life), while in weaned piglets (fourth week of life) rotavirus and ETEC were most prevalent. On 22 of the 24 piglet production farms examined at least one of the investigated pathogens was detected. Coronavirus was diagnosed in 66.7%, I. suis in 62.5%, rotavirus in 20.8% and C. parvum in 8.3% of the farms. These results underline the fact that despite the hygienic, technical and immune preventive efforts during the last years, enteropathogens are still common in German piglet production units.

Animals↗
PubMed2001

Hydatid echinococcosis (Echinococcus granulosus) in a laboratory colony of pig-tailed macaques (Macaca nemestrina).

Several cases of hydatid echinococcosis were diagnosed in a laboratory colony of 19 pig-tailed macaques (Macaca nemestrina) at the Paul Ehrlich Institute, Germany. Three hydatid cysts were found in the liver of an euthanized animal. The diagnosis of an Echinococcus granulosus infection was confirmed by histopathology and the results of a specific polymerase chain reaction. The serum of five of 14 other monkeys tested for Echinococcus antibodies using a genus-specific enzyme-linked immunosorbent assay (ELISA) was positive or weakly positive; none of the animals, however, showed specific reactions in a E. multilocularis-specific ELISA. On ultrasonographic examination, alterations in the liver were found in four of the serologically positive monkeys, and two animals showed clinical signs such as progressive anorexia, apathy and icterus. The monkeys had most probably acquired the E. granulosus infection in their breeding colony in Slovenia.

Animals↗
PubMed2001

Pattern of Eimeria oocyst output and repeatability in naturally infected suckling Rhön lambs.

The faeces of 14 Rhön lambs were examined every second day between 7 and 99 days of age for the presence of Eimeria oocysts. Eimeria absata, E. bakuensis, E. faurei, E. granulosa, E. intricata, E. ovinoidalis, E. pallida, E. parva and E. crandallis/weybridgensis were identified. The predominant species were E. ovinoidalis, E. parva, E. crandallis/weybridgensis and E. bakuensis. Using a statistical model, the oocyst excretion rate was described as a sequence of periods with decreasing levels and varying length ('excretion periods') interrupted by intervals with no or very low oocyst counts. Several variables could be deduced from these two parameters, including the length of an excretion period and the maximum output during an excretion period. Thc estimated repeatability for oocyst counts for the different species ranged from 0.05 to 0.41. This result provides a starting point for possible genetic selection based on faecal oocyst counts of Rhön sheep for resistance to Eimeria infections.

Animals↗
PubMed2001

Hypoxia affects expression of circadian genes PER1 and CLOCK in mouse brain.

The key elements of circadian clockwork and oxygen homeostasis are the PAS protein family members PER and CLOCK and hypoxia-inducible factor 1alpha (HIF-1alpha). The PAS domain serves as an interface for protein-protein interactions. We asked whether a cross-talk exists between the PAS components of hypoxic and circadian pathways. We found several isoforms of PER1 protein that exhibit tissue-specific size differences. In the mouse brain, a predominantly nuclear 48 kDa isoform that followed a daily rhythm was observed. The 48 kDa form was found in the nuclear fractions derived from mouse liver, Swiss3T3 fibroblasts, and N2A neuroblastoma cells. In mouse kidney and human 293 kidney cells, a 55 kDa PER1 form was detected. CLOCK was observed as a predicted 100 kDa protein in rat-1 cells and in all analyzed mouse tissues including brain, liver, kidney, and spleen. In contrast to PER1, CLOCK protein expression was not rhythmic. Exposure to hypoxia led to increased PER1 and CLOCK protein levels in mice. Based on coimmunoprecipitation experiments that showed protein-protein interaction between PER1 and the alpha subunit of HIF-1, we suggest that these hypoxic effects may be modulated by HIF-1alpha.-Chilov, D., Hofer, T., Bauer, C., Wenger, R. H., Gassmann, M. Hypoxia affects expression of circadian genes PER1 and CLOCK in mouse brain.

3T3 Cells↗