Interaction of Amyloid-β-(1-42) Peptide and Its Aggregates with Lipid/Water Interfaces Probed by Vibrational Sum-Frequency Generation Spectroscopy

In this study, we use surface-sensitive vibrational sum-frequency generation (VSFG) spectroscopy to investigate the interaction between model lipid monolayers and Aβ(1-42) in its monomeric and aggregated states. Combining VSFG with atomic force microscopy (AFM) and thioflavin T (ThT) fluorescence measurements, we found that only small aggregates with probably a β-hairpin-like structure adsorbed to the zwitterionic lipid monolayer (DOPC). In contrast, larger aggregates with an extended β-sheet structure adsorbed to a negatively charged lipid monolayer (DOPG). The adsorption of small, initially formed aggregates strongly destabilized both monolayers, but only the DOPC monolayer was completely disrupted. We showed that the intensity of the amide-II' band in achiral (SSP) and chiral (SPP) polarization combinations increased in time when Aβ(1-42) aggregates accumulated at the DOPG monolayer. Nevertheless, almost no adsorption of preformed mature fibrils to DOPG monolayers was detected. By performing spectral VSFG calculations, we revealed a clear correlation between the amide-II' signal and the degree of amyloid aggregates (e.g., oligomers or (proto)fibrils) of various Aβ(1-42) structures. The calculations showed that only structures with a significant amyloid β-sheet content have a strong amide-II' intensity, in line with previous Raman studies. The combination of the presented results substantiates the amide-II(') band as a legitimate amyloid marker.

456Risk of arterial calcification by conventional vitamin K antagonist treatment

Background

Vitamin K antagonists (VKA) are the most frequently prescribed oral anticoagulants worldwide although new oral anticoagulants (NOAC) have become an important alternative. VKA inhibits Vitamin K1 necessary to produce coagulation factors but also Vitamin K2, which is essential in the activation of matrix-Gla protein, thought to be a strong local inhibitor of arterial calcifications.

Purpose

The aim was to investigate, whether VKA treatment is associated with coronary artery calcification (CAC) in a population with no prior cardiovascular disease (CVD).

Methods

We collected data on cardiovascular risk factors and CAC scores from cardiac CT scans performed as part of clinical examinations (n=9,672) or research studies (n=14,166) in the period 2007–2017. Data on use of VKA and NOAC was obtained from the Danish National Health Service Prescription Database. The association between VKA treatment duration and categorized CAC score was investigated by ordered logistic regression while adjusting for covariates. The independent variables included in the model were: age, gender, smoking, body mass index (BMI), diabetes mellitus, hypertension, hypercholesterolemia and/or statin treatment, family history of CVD, estimated glomerular filtration rate, VKA treatment duration and NOAC treatment duration. The categorisation of CAC was: 0, 1–99, 100–399 and ≥400 AU, corresponding to no, mild, moderate and severe atherosclerotic plaque burden, respectively.

Results

The final study population consisted of 17,254 participants (median 67 years old, 75% males) with no prior CVD, of which 1,748 (10%) and 1,144 (7%) had been treated with VKA or NOAC, respectively. A longer duration of VKA treatment was associated with higher CAC categories (Figure). For each cumulative year of VKA treatment, the odds of being in a higher CAC category, i.e. having more severe atherosclerosis, increased (odds ratio (OR)=1.032, 95% CI 1.009–1.057). All traditional cardiovascular risk factors were also associated with CAC. In contrast, NOAC treatment duration was not associated with CAC category (OR=1.004, 95% CI 0.937–1.075). In a sensitivity analysis of patients without statin treatment (n=12,143), the association between VKA treatment and CAC category remained unchanged. There was no significant interaction between VKA treatment duration and age on CAC category.

Conclusion

Adjusted for cardiovascular risk factors, VKA treatment – in contrast to NOAC - is associated with more severe CAC. Additional studies are required to clarify the clinical importance of this association in terms of hard cardiovascular endpoints.

Acknowledgement/Funding

Novo Nordisk Foundation and Independent Research Fund Denmark

Fixation stability and implication for multifocal electroretinography in patients with neovascular age-related macular degeneration after anti-VEGF treatment

PURPOSE

To quantify fixation stability in patients with neovascular age-related macular degeneration (nAMD) at baseline, 3 and 6 months after anti-vascular endothelial growth factor (anti-VEGF) treatment and furthermore asses the implications of an unsteady fixation for multifocal electroretinography (mfERG) measurements.

METHODS

Fifty eyes of 50 nAMD patients receiving intravitreal anti-VEGF treatment with either bevacizumab or ranibizumab and eight eyes of eight control subjects were included. Fixation stability measurements were performed with the Eye-Link eyetracking system and the retinal area in degrees² (deg²) containing the 68 % most frequently used fixation points (RAF68) was calculated. MfERG P1 amplitude and implicit time were analyzed in six concentric rings and as a summed response. Patients were examined at baseline, 3 and 6 months. Four different mfERG recordings were performed for the control subjects to mimic an involuntary unstable fixation: normal central fixation, 2.4°, 4.8°, and 7.1° fixation instability.

RESULTS

For control subjects, a fixation instability of 2.4° (corresponding to the central hexagon) did not reduce mfERG ring amplitudes significantly, whereas 4.8° and 7.1° fixation instability reduced the amplitudes significantly in rings 1 and 2 (p < 0.001) as well as in the peripheral rings in the 7.1° instability condition (p < 0.001). Fixation stability improved non-significantly for patients at 3 and 6 months. The size of the retinal area of fixation was at baseline, 3 and 6 months negatively correlated to visual acuity (VA) (r_baseline = -0.65, r_{3 months} = -0.60, and r_{6 months} = -0.66 respectively, p < 0.001) and mfERG amplitudes of the three innermost rings (r_baseline = -0.29, p = 0.042, r_3 months = -0.43, p = 0.003 and r_6 months = -0.31, p = 0.042). The VA cutoff for a fixation area less than 5 deg² (approximately the central hexagon) was 65, 77, and 68 ETDRS letters (corresponding a maximal Snellen equivalent of 0.31) at baseline, 3 and 6 months, respectively.

CONCLUSIONS

MfERG amplitudes in recordings of nAMD patients are at substantial risk of being reduced due to poor fixation as a large number of patients may use a fixation area of more than 5 deg². Fixation monitoring during recording as well as interpretation of results should be performed with care, especially in patients with poor visual acuity.

Interferon-gamma suppresses S100A4 transcription independently of apoptosis or cell cycle arrest

The S100A4 protein has been associated with increased metastatic capacity of cancer cells, and recent studies have suggested a correlation between the expression level of S100A4 and the prognostic outcome for patients with various types of cancer. The knowledge about the mechanisms underlying the metastasis-promoting effects is still limited, and the aim of the present study was to elucidate signal transduction pathways involved in the regulation of S100A4. After treatment of human carcinoma cells with interferon-gamma (IFN-gamma), we observed downregulation of S100A4 both at mRNA and protein levels. The effect was not dependent on IFN-gamma-induced apoptosis or IFN-gamma-mediated cell cycle arrest. Moreover, IFN-gamma-mediated decrease in mRNA stability could not account for the observed decrease in S100A4 transcript level. Finally, microarray analysis suggests ISGF3G, ETV5, ZNF133 and CEBPG as possible candidate genes involved in IFN-gamma-mediated repression of S100A4.

Expression of S100A4, E-cadherin, alpha- and beta-catenin in breast cancer biopsies

In 66 breast cancer biopsies, the expression of the Ca(2+)-binding protein S100A4, E-cadherin, alpha- and beta-catenin was examined by immunohistochemistry, and the results were related to clinical and pathological parameters. High levels of S100A4 were found to significantly correlate with histological grade (P=0.030) and loss of oestrogen receptor (P=0.046), but not to the time interval between surgery and development of distant metastasis (P=0.51) or to patient survival (P=0.89). Loss of E-cadherin expression, associated with altered cell-cell adhesion, showed a highly significant association to overall survival (P=0.020) and metastasis-free period (P=0.0052). In multivariate analysis, only lymph node involvement was a more significant predictor of patient demise. No association was found between expression of S100A4 and any single member of the cadherin-catenin complex, but a trend (P=0.053) towards reduced expression of one or several of these proteins and S100A4 immunoreactivity was observed. In conclusion, although our results suggest an association between S100A4 expression and an aggressive tumour phenotype, no relationship to overall survival was found. Deregulation of E-cadherin expression, however, was of high prognostic significance.

The need for a veterinary antibiotic policy

The international recognition of the 'stable to table' approach to food safety emphasises the need for appropriate and safe use of antibiotics in animal production. An appropriate use of antibiotics for food animals will preserve the long-term efficacy of existing antibiotics, support animal health and welfare and limit the risk of transfer of antibiotic resistance to humans. Furthermore, it may promote consumer confidence in the veterinary use of antibiotics. In advancing these arguments, the authors of this article argue that there is a need for a visible and operational policy for veterinary use of antibiotics, paying particular attention to the policies that are being developed in Denmark.

Regulation of tissue-degrading factors and in vitro invasiveness in progression of breast cancer cells

Hormone-independent growth and invasiveness represent phenotypic properties acquired during early progression of breast cancer. We compared human mammary adenocarcinoma cells, MCF-7, which are estrogen-dependent and poorly metastatic, with the estrogen-independent and highly metastatic subline, MCF7/LCC1, with regard to expression of tissue-degrading factors of the matrix metalloproteinase (MMP)-and urokinase (uPA)-dependent degradative pathways, as well as for their in vitro invasive properties. Both cell lines showed low constitutive mRNA expression of the MMP inhibitor TIMP-1. Baseline expression of TIMP-2 mRNA was also very low in MCF-7 cells, whereas the MCF7/LCC1 level was much higher (approximately 10-fold). Furthermore, both cell lines revealed low constitutive capacity to migrate in an in vitro invasion assay. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA; 100 nM) induced the mRNAs for TIMP-1 as well as for MMP-1, MMP-9, the uPA receptor, and the uPA inhibitor PAI-1, amongst which only the responses of MMP-9 and PAI-1 were cell-specific. The mRNA levels of MMP-9 and PAI-1 were approximately 10-fold and approximately 15-fold higher in MCF7/LCC1 cells compared to MCF-7 cells. The secretion of immunoreactive PAI-1 was considerably elevated (> 20-fold) in TPA-treated MCF7/LCC1 cells, whereas the TPA-dependent level of 92-kDa MMP-9 was only approximately 2-fold higher in MCF7/LCC1 cells than in MCF-7 cells. In both cell lines treatment with TPA was associated with an increase (approximately 10-fold) in in vitro migration, which in the MCF7/LCC1 cells was significantly attenuated by a reconstituted basement membrane extract (Matrigel). These data suggest that TPA-responsive in vitro invasive properties that are probably associated with PAI-1 expression may co-vary with progression from hormone-dependent to -independent breast cancer.

Differentiation of toxigenic from nontoxigenic isolates of Pasteurella multocida by enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay (ELISA) was developed for the rapid and simple differentiation of toxigenic from nontoxigenic strains of Pasteurella multocida. The sandwich ELISA is based on two different murine monoclonal antibodies with specificity for the P. multocida toxin. The ELISA, which is now used as a routine test in Denmark, has several advantages compared with previously described biological tests.

Characterization of the dermal lesions induced by a purified protein from toxigenic Pasteurella multocida

The dermonecrotic effect of purified Pasteurella multocida toxin (PMT) was studied sequentially in guinea pigs and rats. The skin reaction was initially an acute inflammatory reaction, with edema and emigration of neutrophils and a few eosinophils and diapedesis of some erythrocytes. Four hours after intracutaneous injection the vessels were congested and thrombocytes were focally attached to the endothelial wall. Twenty-four h after the injection the inflammatory reaction appeared more severe and venules and arterioles were thrombosed. Necrotic changes were seen in hair follicles and in striated muscle fibers. Crude extracts from P. multocida and Clostridium perfringens injected intracutaneously into guinea pigs induced skin lesions qualitatively similar to the lesions induced by the purified PMT, indicating that dermonecrotic bacterial toxins may share similar biochemical properties.

Production of toxin in strains previously classified as Pasteurella multocida

169 strains of P. multocida ssp. multocida, 24 strains of P. multocida ssp. septica, 22 strains of P. multocida ssp. gallicida, and 8 strains of P. avium and P. canis, respectively, were tested for toxin production in EBL-cell culture assay. Toxin production was only demonstrated in strains belonging to P. multocida ssp. multocida. Toxigenic strains were derived from pigs, calves, cats, dogs, rabbits and turkeys.

The pathogenesis of persistent turbinate atrophy induced by toxigenic Pasteurella multocida in pigs

Six one-week-old piglets were pretreated with a 1% acetic acid solution for two days in one or both nostrils. Three piglets were not treated with acetic acid. Three days after treatment all nine piglets were inoculated in both nostrils with a toxigenic type D strain of Pasteurella multocida. Three piglets were killed seven days after inoculation; one died spontaneously 13 days after inoculation and the remaining pigs were killed at approximately 90 kg body weight, i.e., five to six months of age. All acetic acid-treated animals developed severe atrophy of the turbinates in the treated nostrils. Untreated nostrils were normal. The present results showed that toxigenic P. multocida can induce turbinate atrophy that persisted until 90 kg body weight when the lesions were similar to spontaneous atrophic rhinitis in pigs. The turbinate atrophy was not accompanied by inflammatory reaction, atrophy of other bone structures, or lesions in other organs. The experiment showed furthermore that toxigenic P. multocida may be present in the tonsils of control animals without causing turbinate atrophy. A pathogenesis for atrophic rhinitis in pigs is proposed.

Characterization of Pasteurella species isolated from lungs of calves with pneumonia

During routine bacteriological examination of pneumonic calf lungs it was experienced that many Pasteurella multocida-like isolates had a fermentation pattern different from what is generally accepted for P. multocida sensu stricto. Forty-one out of 50 strains selected for further investigation were phenotypically related and formed a group of indole-, mannitol-and sorbitol-negative P. multocida-like strains, which was tentatively designated taxon 13. Deoxyribonucleic acid/deoxyribonucleic acid hybridizations including both ornithine positive and ornithine negative strains of taxon 13 allowed the classification of the former as P. multocida biovar 6 and the latter as V factor independent strains of Haemophilus avium.

Influence of vaccination of sows with Bordetella-Pasteurella vaccines on the occurrence of atrophic rhinitis among their offspring after experimental infection with Bordetella bronchiseptica and toxigenic Pasteurella multocida

Experimental infections with Bordetella bronchiseptica and a toxigenic strain of Pasteurella multocida were carried out in newborn piglets from 25 sows. Severe progressive atrophic rhinitis corresponding to the natural disease was produced. The effect of vaccination of sows during pregnancy with two vaccines containing antigens from B. bronchiseptica and toxigenic P. multocida on the incidence of nasal lesions in the offspring was studied.

The bacteriology of endocarditis in slaughter pigs

Streptococcus suis was isolated from 11 (10 per cent) out of 107 cases of endocarditis in slaughter pigs from which bacteria of any kind were isolated. Seven of the isolates belonged to the capsular serotypes 1, 2 and 1/2. Four were non-typable owing to lack of capsule. The organism isolated most often was Erysipelothrix rhusiopathiae, which was found in 68 (64 per cent) cases.

The pathogenesis of atrophic rhinitis in pigs induced by toxigenic Pasteurella multocida

The pathogenesis of atrophic rhinitis was studied in an experiment in which piglets were infected with a toxigenic type D Pasteurella multocida strain in the right half of the nasal cavity. Two days before inoculation the nasal mucosa on the right side had been subjected to mild irritation by intranasal instillation of a weak solution of acetic acid. The untreated (left) half of the nasal cavity served as an intrinsic control. Macroscopically, changes in the turbinates were already appreciable at 3 days p.i., and pronounced turbinate atrophy was noted at 7 days p.i. At 14 days p.i. deviation of the snout and almost complete turbinate atrophy was observed. The turbinates in the untreated half of the nasal cavity developed normally. Histologically, the changes were initially characterized by bone resorption mediated by an increased number of osteoclasts. Later osteoclasts were sparse, and there was an apparent disruption of osteoid synthesis. Ultrastructurally, the osteoblasts showed nuclear indentations and dilatation of the endoplasmic reticulum. Since no inflammatory reaction was observed, the hypothesis is advanced that atrophic rhinitis in pigs is caused by a P. multocida-produced factor which will stimulate bone resorption and suppress osteoid synthesis.

Serology of capsulated streptococci pathogenic for pigs: six new serotypes of Streptococcus suis

A total of 138 capsulated strains of streptococci were isolated from pigs with various infections, notably septicemia and bronchopneumonia. Biochemically all strains were similar, and 31 strains were serologically identical to the previously described groups R, S, and RS streptococci, provisionally designated Streptococcus suis types 1, 2, and 1/2 by Elliot. The remaining 107 strains could be divided into six new capsular serotypes of S. suis.

Effect on the incidence of atrophic rhinitis of vaccination of sows with a vaccine containing Pasteurella multocida toxin

Combined experimental infections with Bordetella bronchiseptica and either a toxigenic or a non-toxic strain of P. multocida were carried out in newborn specific pathogen free piglets born to 25 sows. Pigs inoculated with B. bronchiseptica and toxin-producing P. multocida developed severe progressive atrophic rhinitis corresponding to the natural disease. The effect of vaccination of sows with a toxin-containing P. multocida vaccine on the incidence of nasal lesions in the offspring was studied.

The influence of sow colostrum trypsin inhibitor on the immunoglobulin absorption in newborn piglets

The influence of sow colostrum trypsin inhibitor (SCTI) on the immunoglobulin absorption from the gut of 16 newborn colostrum-deprived piglets was investigated in a paired feeding experiment.

Three times at 1 h intervals the piglets were fed an experimental diet consisting of sow milk, purified swine serum immunoglobulins containing agglutinins against Bordetella bronchiseptica, and purified SGTI (diet I) or saline (diet II). The serum concentrations of IgG, IgM, IgA, and antibodies for B. bronchiseptica were measured by single radial immunodiffusion and by a tube agglutination procedure and used to evaluate the immunoglobulin absorption. Four and 6 h after the first experimental meal, blood samples from the piglets given SGTI in their diet had a generally higher level of IgG, IgA and aggutinins against B. bronchiseptica than blood samples from the piglets d no SGTI. No real differences were found in the IgM levels. Although the piglets fed no SGTI all showed a considerable immunoglobulin absorption, the SCTI was found to have a statistically significant positive influence on the IgG and IgA absorption.

The aetiological significance of Bordetella bronchiseptica and Pasteurella multocida in atrophic rhinitis of swine

Experimental infection with either pure culture of Bordetella bronchiseptica or B. bronchiseptica and a toxin-producing strain of Pasteurella multocida was studied in newborn piglets from 26 sows. Pigs inoculated with B. bronchiseptica alone got mild lesions, whereas pigs inoculated with both organisms showed clinical and pathological signs of atrophic rhinitis, corresponding to the progressive natural diseases. The effect of vaccinating sows against B bronchiseptica during pregnancy was studied.

Studies on a haemolytic substance in Yersinia enterocolitica

Yersinia enterocolitica serotype O3 was found to produce a haemolytic substance which could be released from the bacterial cells by sonic disintegration. The substance was non-dialysable, thermolabile, antigenic, and sensitive to trypsin. Chromatographic studies indicated a high molecular weight. Erythrocytes from different mammalian species differed in sensitivity to the haemolytic substance. Y. enterocolitica serotypes O8 and O9 produced no haemolytic substance.

Infection with RS streptococci in pigs

RS streptococci were isolated from pigs that died in an outbreak of septicemia and meningitis in a Danish herd of swine. Most of the affected pigs were 7-9 weeks old. Experimental inoculation of SPF pigs with a culture of the streptococci isolated from the brain of a pig that had died during the outbreak showed that the bacterium was pathogenic for pigs. Out of 35 8-15-week-old pigs inoculated, nine developed arthritis and one died in septicemia. At necropsy, four of the pigs were found to have endocarditis. Blood cultures from pigs with endocarditis were constantly positive throughout the experiment, i.e., until the pigs died 5-7 weeks after inoculation. In vivo loss of capsular antigen was observed. A human strain of R streptococci isolated from a case of septicemia was also shown to be pathogenic for pigs.

Studies on the interaction between different O-serotypes of Yersinia enterocolitica and HeLa cells

Eighty strains of Yersinia enterocolitica were examined for their ability to invade HeLa cells. The following O-serotypes were found to be invasive: 1, 3, 4a, 4c, 5b, 8, 9, 15a, 18, 20, 21 and 22. Biochemically, these types are either indole-, aesculin-, and salicin-negative, or indole-positive but aesculin- and salicin-negative. Other serotypes of Y. enterocolitica did not invade HeLa cells. Biochemically, these non-invasive strains are indole-, aesculin- and salicin-positive. Also the non-sucrose-fermenting strains of O-serotypes 11 and 12 were non-invasive. The interaction with HeLa cells was not restricted to viable bacteria, since also bacterial cells inactivated by formalin or ultraviolet light could gain entrance to the HeLa cells. Heating of the bacteria to 100 degrees C for 30 min. completely inhibited their invasiveness. Monolayer cultures of porcine kidney cells were also invaded by strains which invaded HeLa cells.

Studies on Yersinia enterocolitica isolated from swine and dogs

Yersinia enterocolitica serotype 03 was isolated from the colon contents of 27 (4.5%) of 599 bacon pigs on slaughter. Two (1.7%) out of 115 dogs were positive by culture for this human-athogenic serotype of Y. enterocolitica. A number of other serotypes of Y. enterocolitica were also obtained both from porcine and canine enteric contents (4b, 5a, 6, 7, 11, 12, 15, 17, 19, 26b, and non-typeable strains). All these serotypes are supposedly non-pathogenic for man and may possibly originate from the microflora of the environment. Haemolysis on bovine blood agar was observed for strains belonging to O-serotype 3.

Isolation of Mycoplasma bovoculi from cases of infectious bovine keratoconjunctivitis

Five outbreaks of infectious bovine keratoconjunctivitis were examined for bacteria and mycoplasmas. Mycoplasma bovoculi was demonstrated in four of the five outbreaks. Other mycoplasmatales were represented by Ureaplasma in one sample. Moraxella bovis and Neisseria ovis were found in all the outbreaks, the former being present in the vast majority of the animals. Transmission experiments with Mycoplasma bovoculi and Moraxella bovis in combination were carried out on four young, colostrumdeprived calves. Mycoplasma bovoculi appeared to have an enhancing effect on the pathogenicity of Moraxella bovis.

Studies on immunoglobulins and trypsin inhibitor in colostrum and milk from sows and in serum of their piglets

The concentrations of IgG, IgM, IgA and the specific sow colostrum trypsin inhibitor (SCTI) were measured by radial immunodiffusion in colostrum and milk samples from sows and in serum samples from their offspring during the suckling period. A clear time dependence was found for all the measured variates in both whey and serum. Statistically significant positive correlations were found between, on the one hand, concentrations of IgG and IgA, but not IgM, in sera from 39 suckling piglets 1 and 3 days old, and, on the other hand, concentrations of the same immunoglobulins and of the trypsin inhibitor in maternal colostrum (n = 7). Multiple regression analyses showed that at day 1 and day 3 the levels of both IgG and IgA in serum samples from the suckling piglets were positively influenced by both the SCTI and the IgG or IgA contents in maternal colostrum.

Congenital ataxia and tremor with cerebellar hypoplasia in piglets borne by sows treated with Neguvon vet. (metrifonate, trichlorfon) during pregnancy

In 1976--77 The State Veterinary Serum Laboratory received new-born pigs which had shown nervous disorders immediately after birth. In all the cases the sows had been treated with Nevugon vet. (metrifonate, trichlorfon) during pregnancy. In the majority of the affected litters the morbidity and lethality were 100 per cent. Analysis of the breeding data from some of the herds suggested that the period during which the fetuses are sensitive is rather narrow, i.e., approximately from day 45 to day 63. The disease was reproduced experimentally and it was concluded that oral treatment of pregnant sows with Neguvon vet. about the middle of the gestation period can result in severe nervous disorders in the piglets. Clinically the disease is characterized by ataxia and tremor, and corresponding to that there is a pronounced hypoplasia of the cerebellum and also a reduction in the size of the spinal cord.

Effect of vaccination of sows with Bordetella bronchiseptica on the incidence of atrophic rhinitis in swine

Vaccination of pregnant sows with Bordetella bronchiseptica was performed in an SPF herd with clinical atrophic rhinitis. Agglutinins against the organism were induced in serum and colostrum by the vaccination. The antibody titres were generally higher in colostrum than in corresponding serum samples. The frequency at slaughter of turbinate atrophy (+, ++, +++) was lower among pigs from vaccinated sows (11%) than in pigs borne by unvaccinated sows (20%). In the control group a lower daily weight gain was observed in pigs with turbinate atrophy than in pigs with normal noses. The mean daily weight gain in pigs with turbinate atrophy borne by vaccinated sows was slightly lower than in pigs without atrophy of conchae, but the difference was not significant. A specific immunological prophylaxis might be an alternative to antibacterial treatment in herds where atrophic rhinitis is aetiologically related to B. bronchiseptica infection.

[Feed supplementation with selenium in relation to the vitamin E-selenium deficiency syndrome in pigs (author's transl)]

After the addition of selenium to swine feed (max. 0.1 ppm) was legalized in Denmark in 1975, a marked reduction has occurred in the incidence of hepatosis dietetica (HD) in the material received at the State Veterinary Serum Laboratory for diagnostic examination, while the incidence of mulberry heart disease (MHD) appears to be unchanged (Table I). In a material collected before the addition of selenium to swine feed was permitted, the selenium content in liver and heart was found to be significantly lower in the pigs that had died of MHD than in normal pigs, but higher than in pigs that had died of HD (Table II). These observations tend to support the view that feed supplementation with selenium is more effective to prevent HD than MHD.

[Actinobacillus infections in swine (author's transl)]

Actinobacilli infections in pigs are relatively rare. Most cases were septicaemic in the first week of life. With increasing age manifestations after generalized infections were characteristic, such as arthritis, polyarthritis, endocarditis, nephritis, osteomyelitis and embolic pneumonia. Of 34 porcine strains 33 were identified as A. equuli and only one was identical with A. suis. The justification of retaining this species is discussed.

Isolation of Yersinia enterocolitica from Danish swine and dogs

Seventeen strains of Yersinia enterocolitica were isolated on examination of the caecal contents from 100 bacon pigs at slaughter. In another material consisting of 222 pigs with various diseases, the bacterium was found in 12 cases. Three out of 40 dogs were positive for the bacterium. Seven of the porcine and one of the canine strains belonged to serotype O 3, which is a human pathogen.

Some factors influencing the haemolysis of Bordetella bronchiseptica

Strain-dependent variations in the ability of Bordetella bronchiseptica to produce haemolysis on solid media exist. Haemolysis is strongest at an acid reaction and will not take place if the reaction is too alkaline. Peptone and glutamine inhibit haemolysis and favour growth. The vigorous growth rapidly produced an alkaline reaction which inhibits the haemolysis.

The serology of Bordetella bronchiseptica isolated from pigs compared with strains from other animal species

The serology of freshly isolated strains of Bordetella bronchiseptica from pigs and some other animal species was studied by the agglutination and agglutinin absorption tests. Differentiation was made between heat stable O-antigens and heat labile K-antigens. All the strains examined contained a common O-antigen (1). In addition, three heat stable antigens were detected. The heat labile antigens of freshly isolated strains were found to be very different. The major antigens 2 and 3 were not found in combination. A common weak K-antigen (1) was found in all strains. The pig strains were found to be serologically identical (0, 1, 2; K 1, 2). The same serotype was isolated from a rabbit. Another rabbit strain was found to be similar to a strain isolated from an SPF-rat (O, 1, 3; K 1, 3, 4). The antigenic pattern found in two cat strains was O 1, 3; K 1, 3. Typing of freshly isolated strains from pigs with monospecific factor sera confirmed that all the strains so far examined were serologically identical. This uniform serology hampers epidemiological studies of porcine bordetellosis by antigenic analysis. The occurrence of serologically different serotypes of B. bronchiseptica is of significance in the diagnostic bacteriology since the final diagnosis must be confirmed by a serological test.