Failure to improve energy balance or dehydration by drenching transition cows with water and electrolytes at calving.

The disease risk is very high among transition cows that may suffer from poor appetite. The aim of the present study was therefore to investigate the effect of drenching on energy balance, hydration state and selected production parameters in fresh cows. Twenty-one Danish Holstein-Friesian dairy cows in late pregnancy were randomly allocated to either treatment (TG) or control group (CG). TG cows were drenched twice with 20 l of water containing a mixture of calcium propionate, MgSO(4), and KCL specifically developed for prophylactic treatment of fresh cows. The results indicated that cows become dehydrated around calving, losing on average 53 l (TG) and 24.5 l (CG) of extra-cellular fluid, respectively. The drenching volume applied in the present study did not affect the degree of hydration after calving. Based on blood NEFA and BHB values it was shown that drenching caused a reduction in the degree of negative energy balance (NEB). Somatic cell count (SCC) for cows in first lactation was lower in the TG compared to CG. Milk yield was unaffected by treatment. We conclude that prophylactic drenching added little to the health promotion in the transition cows in the present study. Instead, increased focus on management routines would probably be of more value.

Assessment of chemoreflex sensitivity in free breathing young subjects by correction for respiratory influence.

BACKGROUND: The assessment of autonomic function is an important tool for risk stratification in critically ill patients. Peripheral cardiac chemoreflex sensitivity has been considered a marker for increased risk of sudden cardiac death. In normals, the evaluation of peripheral cardiac chemoreflex sensitivity is performed under controlled breathing conditions during inhalation of hypoxic gas. Since this is poorly tolerated by patients, they are commonly studied under hyperoxic conditions, which are not physiological. METHODS: We studied 20 healthy volunteers who underwent free and controlled breathing of a hypoxic gas mixture (10% O2 in N2) over 5 min. Values of peripheral cardiac chemoreflex sensitivity, corrected for respiratory influence, were compared with the results obtained experimentally under controlled breathing conditions in the same subjects. RESULTS: We found a substantial difference between values obtained during free and controlled breathing (3.64 +/- 0.81 vs. 1.53 +/- 0.32 ms/mmHg, respectively; P < 0.05). After application of a respiratory correction, described and validated in this article, no significant difference was seen for these values (0.89 +/-0.91 vs. 1.53 +/- 0.32 ms/mmHg, P = 0.46). CONCLUSIONS: This approach allows the evaluation of peripheral cardiac chemoreflex sensitivity in free breathing subjects. This correction could improve the assessment of cardiac chemoreflex sensitivity in patients with cardiorespiratory disorders, who find it difficult to control their breathing according to an experimental protocol.

Autonomic dysfunction in the ICU patient.

The sympathetic-parasympathetic balance may be altered in critically ill patients. Assessment of autonomic function provides information concerning prognosis, pathogenesis, and treatment strategies in ICU-relevant disorders. Proven tools are heart rate variability, baroreflex sensitivity, and, with limitations, cardiac chemoreflex sensitivity. New nonlinear methods are being evaluated that may predict risk more precisely in critically ill patients. This article summarizes application of these tools in the ICU. In addition, a model is introduced for investigating the impaired autonomic function in multiple organ dysfunction syndrome and sepsis, integrating extrinsic mechanisms and factors that are intrinsic to the cardiac tissue. By this combined approach, the authors hope to gain insight into the pathogenesis of multiple organ dysfunction syndrome. New pathophysiologic concepts are needed for the development of treatment strategies for this life-threatening disease.

P300 response: habituation.

This study used the "oddball" counting paradigm to examine the possible habituation of the auditory P300 response. Twenty subjects kept a mental record of the number of rarely occurring tone pips presented in a series of more frequently occurring tone pips. Data were collected continuously until responses to 150 rare tone pips were obtained. Findings indicated that the P300 complex decreased in amplitude as a result of repeated stimulation. The decline was logarithmic, not linear, which suggests a stabilization of the amplitude over time. We suggest that the attenuation of amplitude was habituation and not a result of a recovery cycle.

[A conbribution to the characterization of asparagus virus 2 (author's transl)]. / Ein Beitrag zur Charakterisierung des Spargel-Virus 2.

In host range investigations with 152 plant species of 37 families, 96 species from 28 families proved to be experimentally susceptible to asparagus virus 2 (AsV 2). From these, 82 species of 26 families were systematically infectible and 14 species of 10 families only locally. Most frequently were symptomless systemic infections. Of 86 species, their susceptibility for AsV 2 was unknown before. The number of families that contant experimental hosts of the virus increased from 11 to 33. Transmission of AsV 2 was neither possible with Myzus persicae nor with Cuscuta californica or C. campestris. AsV 2-infected mother plants transmitted the virus by about 40 per cent to their seedings. Open-pollinated plants, not infested by AsV 2, showed 3 to 22 per cent of infected seedings. Mechanical back-transmission of AsV 2 from test plants to asparagus succeeded only in one case. The properties of the virus in vitro were as follows: thermal inactivation point between 64 and 66 degrees C, dilution end point between 10(-3) and 10(-4), stability in sap, stored at room temperature, up to 96 hours. Serological investigations demonstrated no relationship to the virus to numerous other viruses. An antiserum with a titer of 1 to 16 was useful for the detection of AvV 2 in asparagus sap. Electron microscopical investigations proved for the virus isometric particles for the first time. In negatively stained preparations they had a diameter of 27 nm.