Dynamics of Mycoplasma bovis in Dutch dairy herds during acute clinical outbreaks

Mycoplasma bovis (M. bovis) can cause serious illness in cattle, presenting as arthritis and mastitis in dairy cows and pneumonia, arthritis and otitis media in calves. This study aimed to provide insight into the dynamics of M. bovis within dairy herds, experiencing an acute outbreak in dairy cows. Twenty farms were followed with laboratory testing of suspected dairy cows. Each outbreak farm was sampled five times, at 2 - 3 week intervals, sampling blood and milk and conjunctival fluid from clinically suspected dairy cows and healthy animals from three different age groups: dairy cows, young stock (7 - 24 months) and calves (1 - 6 months). Additionally, bulk tank milk was sampled every visit and environmental samples were taken on the first and last visits. The presence of M. bovis was tested by evaluating antibody titres in blood, bacterial DNA in conjunctival fluid and environmental samples and viable bacteria in milk samples. All data were analysed using logistic regression models, corrected for repeated sampling and within-herd correlation. Sixty percent (12/20) of the herds showed a combination of arthritis and mastitis, while other herds experienced only clinically mastitis (3/20) or arthritis (5/20). From the time an outbreak was confirmed, M. bovis infection was not only present in dairy cows, but also in young stock and calves (80% of the farms). Laboratory tests also confirmed the presence of M. bovis in healthy animals. The M. bovis PCR levels of calves and young stock were highly correlated at all visits (r_total = 0.81, P < 0.01). Furthermore, M. bovis was present in the environment of the animals. At the end of the 3-month study period, none of the 20 clinical outbreak farms were M. bovis-'negative', based on laboratory testing, although hardly any clinical cases were observed at that time.

[Factor structure of the German version of the BIS/BAS Scales in a population-based sample]

BACKGROUND

The Behavioural Inhibition System/Behavioural Activation System Scale (BIS/BAS-Scales) developed by Carver and White 1 is a self-rating instrument to assess the dispositional sensitivity to punishment and reward. The present work aims to examine the factor structure of the German version of the BIS/BAS-Scales.

MATERIAL AND METHODS

In a large German population-based sample (n = 1881) the model fit of several factor models was tested by using confirmatory factor analyses.

RESULTS

The best model fit was found for the 5-factor model with two BIS (anxiety, fear) and three BAS (drive, reward responsiveness, fun seeking) scales, whereas the BIS-fear, the BAS-reward responsiveness, and the BAS-fun seeking subscales showed low internal consistency. The BIS/BAS scales were negatively correlated with age, and women reported higher BIS subscale scores than men.

CONCLUSION

Confirmatory factor analyses suggest a 5-factor model. However, due to the low internal reliability of some of the subscales the use of this model is questionable.

[Meaningful 'romming' (routine outcome monitoring): seeking a balance between userfriendliness and clinical relevance]

BACKGROUND

In the course of the last few years several ROM systems have been developed in which the measurements and feedback are restricted to the therapy outcome in terms of symptom reduction. In these ROM systems the emphasis is on the user-friendliness and on the ease with which the measurements can be implemented in clinical practice. However, research shows that many therapists and clients consider that the measurement of symptom reduction is too simplistic.

AIM

To develop a ROM system that is therapeutically more relevant.

METHOD

We describe the development and implementation of the Leuven Systematic Case study Protocol.

RESULTS

In this multidimensional and multimodal monitoring system the emphasis is on the therapeutic relevance of 'romming:' not simply in terms of symptom reduction, but also in terms of processes of change and growth-orientated processes. In addition, the monitoring system takes into account the unique characteristics of client and therapist and the synergy existing between them.

CONCLUSION

Not only do therapists have to learn to deal with the practical aspects of 'romming', they also need to be trained and supported so that they can deal adequately with a more explicit evaluation and feedback 'culture'.

Anionic and cationic drug secretion in the isolated perfused rat kidney after neonatal surgical induction of ureteric obstruction

OBJECTIVE

To study the pathophysiological changes of renal tubular drug transport mechanisms in congenital renal obstruction, by developing a model for perfusing the isolated kidney (IPK) after neonatal surgical induction of partial ureteric obstruction in Hanover Wistar rats.

MATERIAL AND METHODS

Moderately severe obstruction of the right kidney of male rats was created by burying a segment of the right ureter under the psoas fascia at 5-7 days after birth. Different fluorescent substrates for renal organic anion and cation drug transport systems were added to the IPK, and the concentration of these substances with time analysed in perfusate and urine.

RESULTS

The reproducibility in all groups of the glomerular filtration rate (GFR) and drug excretion was remarkably good. GFR was significantly lower in obstructed kidneys than in unobstructed kidneys. 123Rhodamine, a marker for organic cation and P-glycoprotein transport, had a significantly lower maximum excretion rate in the obstructed than in unobstructed kidneys. Renal fractional clearance (123rhodamine clearance corrected for diminished GFR) was also significantly lower in obstructed kidneys. There was no significant difference in maximum excretion (absolute and corrected GFR) for Lucifer Yellow, a marker for sodium-dependent organic anion transport. The maximum excretion rate of calcein, a marker for sodium-independent organic anion transport, was significantly lower in the obstructed than in the unobstructed kidneys, but significantly higher after correcting for reduced GFR.

CONCLUSION

The IPK is a good model for studying the effect of neonatal renal obstruction on tubular drug transport. These results show that organic anion and cation transport mechanisms are affected differently by obstruction.

The pattern of metastasis of human melanoma to the central nervous system is not influenced by integrin alpha(v)beta(3) expression

We investigated the effect of integrin alpha(v)beta(3) expression on the metastatic pattern of human melanoma cells in the central nervous system (CNS). For this purpose, we developed a hematogenous CNS melanoma metastasis model in nude mice using a modified internal carotid artery infusion technique. This protocol revealed 2 different patterns of CNS metastasis. The integrin alpha(v)beta(3)-expressing melanoma lines Mel57 and Zkr nearly exclusively produced metastases in the brain parenchyma, whereas cells of the BLM and MV3 lines, devoid of integrin alpha(v)beta(3) expression, preferentially metastasized to dura mater and leptomeninges. Treatment with hyaluronidase to obtain single BLM cell suspensions did not influence the metastatic pattern, indicating that this was not simply the result of entrapment of tumor cell aggregates in large-sized leptomeningeal vessels. The role of integrin alpha(v)beta(3) expression in the process of metastasis was tested by transfection of BLM, but did not lead to an altered pattern of metastasis. We did observe, however, slower growth of the transfected tumors, although the in vitro growth rate was unaltered, indicating a reduction in tumorigenicity. We conclude from our findings that CNS metastasis of melanoma cells in the mouse xenograft model occurs in at least 2 different but very reproducible patterns. Although it is predicted that adhesion of tumor cells to endothelial cells plays a role in this phenomenon, tumor cell integrin alpha(v)beta(3) expression per se does not explain the difference in metastatic behavior in the CNS. We assume that other, as yet unknown factors, must be involved.