Effects of direct-fed microbial supplementation on performance and immune parameters of lactating dairy cows.

We evaluated the effects of supplementing bacterial direct-fed microbial (DFM) on performance, apparent total-tract digestibility, rumen fermentation, and immune parameters of lactating dairy cows. One hundred fourteen multiparous Holstein cows (41 ± 7 DIM) were used in a randomized complete block design with an experiment comprising 14 d of a covariate (pre-experimental sample and data collection) and 91 d of an experimental period. Cows were blocked based on energy-corrected milk (ECM) yield during the covariate period and the following treatments were randomly assigned within each block: (1) control (CON), corn silage-based total mixed ration without DFM; (2) PRO-A, basal diet top-dressed with a mixture of Lactobacillus animalis and Propionibacterium freudenreichii at 3 × 109 cfu/d; and 3) PRO-B, basal diet top-dressed with a mixture of L. animalis, P. freudenreichii, Bacillus subtilis, and Bacillus licheniformis at 11.8 × 109 cfu/d. Milk yield, dry matter intake (DMI), and body weight were measured daily, while milk samples for component analysis were taken on 2 consecutive days of each week of data collection. Feces, urine, rumen, and blood samples were taken during the covariate period, wk 4, 7, 10, and 13 for estimation of digestibility, N-partitioning, rumen fermentation, plasma nutrient status and immune parameters. Treatments had no effect on DMI and milk yield. Fat-corrected milk (3.5% FCM) and milk fat yield were improved with PRO-B, while milk fat percent and feed efficiency (ECM/DMI) tended to increase with PRO-B compared with PRO-A and CON. Crude fat digestibility was greater with PRO-B compared with CON. Feeding CON and PRO-A resulted in higher total volatile fatty acid concentration relative to PRO-B. Percentage of neutrophils tended to be reduced with PRO-A compared with CON and PRO-B. The mean fluorescence intensity (MFI) of anti-CD44 antibody on granulocytes tended to be higher in PRO-B compared with CON. The MFI of anti-CD62L antibody on CD8+ T cells was lower in PRO-A than PRO-B, with PRO-A also showing a tendency to be lower than CON. This study indicates the potential of DFM to improve fat digestibility with consequential improvement in fat corrected milk yield, feed efficiency and milk fat yield by lactating dairy cows. The study findings also indicate that dietary supplementation with DFM may augment immune parameters or activation of immune cells, including granulocytes and T cells; however, the overall effects on immune parameters are inconclusive.

Lack of efficacy of mTOR inhibitors and ACE pathway inhibitors as antifibrotic agents in evolving and established fibrosis in Mdr2⁻/⁻ mice.

BACKGROUND & AIMS: Mammalian target of rapamycin and angiotensin-converting enzyme inhibition has been shown to have antifibrotic activity in models of liver fibrosis. The aim of our study was to determine the efficacy of rapamycin, everolimus, irbesartan and captopril, alone and in combination, as antifibrotic agents in the Mdr2(-/-) model of cholestasis both in early injury and established disease. METHODS: Mdr2(-/-) mice were treated for 4 weeks with vehicle, rapamycin (1 mg/kg) or everolimus (5 mg/kg) every second day or with captopril (30 mg/kg/day), irbesartan (10 mg/kg/day) or vehicle. Further groups of 3-week-old Mdr2(-/-) mice were treated with rapamycin and irbesartan in combination (1 mg/kg/day and 10 mg/kg/day) or with rapamycin (2 mg/kg/day) for 4 weeks. Liver injury and fibrosis were compared between treated and untreated animals. RESULTS: There were no significant improvements in liver injury, histology, hepatic hydroxyproline or profibrogenic gene expression following treatment with rapamycin, everolimus, captopril or irbesartan at any time point studied. Likewise, there were no improvements in liver histology or profibrogenic gene expression following combination therapy or high-dose rapamycin treatment. CONCLUSIONS: The antifibrotic effects of rapamycin, everolimus, captopril and irbesartan seen in other models of fibrosis were not replicated in the Mdr2(-/-) model in this study. This highlights the clear need to test specific antifibrotic agents in a number of different animal models. We believe this animal model is ideal to study usefulness of antifibrotic agents in cholestatic liver disease because of the similarity in genetics and hepatic histopathology to human cholestatic liver disease.

Inconsistent hepatic antifibrotic effects with the iron chelator deferasirox.

BACKGROUND AND AIM: Development of effective antifibrotic treatments that can be translated to clinical practice is an important challenge in contemporary hepatology. A recent report on ß-thalassemia patients demonstrated that deferasirox treatment reversed or stabilized liver fibrosis independent of its iron-chelating properties. In this study, we investigated deferasirox in cell and animal models to better understand its potential antifibrotic effects. METHODS: The LX-2 stellate cell line was treated with 5 µM or 50 µM deferasirox (Exjade, Novartis Pharmaceuticals Australia, North Ryde, NSW, Australia) for up to 120 h. Three-week-old multidrug resistance 2 null (Mdr2(-/-) ) mice received oral deferasirox or vehicle for 4 weeks (30 mg/kg/day). Cells and liver tissue were collected for assessment of fibrosis and fibrogenic gene expression. RESULTS: In LX-2 cells treated with 50 µM deferasirox for 12 h, α1(I)procollagen expression was decreased by 25%, with maximal reductions (10-fold) seen following 24-120 h of treatment. Similarly, α-smooth muscle actin (αSMA) expression was significantly lower. Alterations in matrix remodeling genes, specifically decreased expression of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2, were observed. There was no significant difference in hepatic hydroxyproline content in Mdr2(-/-) mice following deferasirox administration (vehicle: 395 ± 27 µg/g vs deferasirox: 421 ± 33 µg/g). Similarly, no changes in the expression of fibrogenic genes were observed. CONCLUSION: Despite reductions in α1(I)procollagen and αSMA expression and alterations in matrix degradation genes in LX-2 cells, deferasirox did not exhibit antifibrotic activity in Mdr2(-/-) mice. Given the positive outcomes seen in human trials, it may be appropriate to study deferasirox in other animal models of fibrosis and/or for a longer duration of therapy.

Effect of preadmission brochures on surgical patients' behavioral outcomes.

This study tested the effects of preadmission teaching brochures on morning admission surgical patients' performance of specific postoperative exercises, teaching time, state anxiety, length of hospital stay, patient satisfaction, and return to functional status. The study participants were 38 women undergoing abdominal hysterectomies. Although the study results show no significant difference between those who received the preoperative teaching brochures and those who did not, the implications for further research are clearly defined. Preoperative nursing interventions that may help patients undergoing hysterectomies manage anxiety and return to function should be tested further.

Potential of adult mammalian lumbosacral spinal cord to execute and acquire improved locomotion in the absence of supraspinal input.

The neural circuitry of the lumbar spinal cord can generate alternating extension and flexion of the hindlimbs. The hindlimbs of adult cats with complete transection of the spinal cord at a low thoracic level (T12-T13) can perform full weight-supporting locomotion on a treadmill belt moving at a range of speeds. Some limitations in the locomotor capacity can be associated with a deficit in the recruitment level of the fast extensors during the stance phase and the flexors during the swing phase of a step cycle. The level of locomotor performance, however, can be enhanced by daily training on a treadmill while emphasizing full weight-support stepping and by providing appropriately timed sensory stimulation, loading, and/or pharmacologic stimulation of the hindlimb neuromuscular apparatus. Furthermore, there appears to be an interactive effect of these interventions. For example, the maximum treadmill speed that a spinal adult cat can attain and maintain is significantly improved with daily full weight-supporting treadmill training, but progressive recruitment of fast extensors becomes apparent only when the hindlimbs are loaded by gently pulling down on the tail during the stepping. Stimulation of the sural nerve at the initiation of the flexion phase of the step cycle can likewise markedly improve the locomotor capability. Administration of clonidine, in particular in combination with an elevated load, resulted in the most distinct and consistent alternating bursts of electromyographic activity during spinal stepping. These data indicate that the spinal cord has the ability to execute alternating activation of the extensor and flexor musculature of the hindlimbs (stepping) and that this ability can be improved by several interventions such as training, sensory stimulation, and use of some pharmacologic agents. Thus, it appears that the spinal cord, without supraspinal input, is highly plastic and has the potential to "learn," that is, to acquire and improve its ability to execute full weight-supporting locomotion on a treadmill belt.

A physiological basis for the development of rehabilitative strategies for spinally injured patients.

After a decade of studies using animal models, there is sufficient information to encourage a reassessment of the potential for recovery of motor function following spinal cord injury in humans. This review focuses on the response of the lumbosacral motor system following spinal cord injury and the effects of rehabilitative strategies such as weight support, loading, and administration of specific pharmacological agonists and antagonists on the maintenance and/or recovery of motor function. Based on clinical experience and review of related studies, the authors suggest a list of eight strategies for the improvement of rehabilitative protocols.

Coordination of motor pools controlling the ankle musculature in adult spinal cats during treadmill walking.

The coordination of the motor pools of two ankle plantar-flexor, i.e. the soleus (Sol) and medial gastrocnemius (MG), and an ankle dorsiflexor, i.e. the tibialis anterior (TA) was quantified by comparing the EMG amplitude relationships in muscle pairs in normal and trained adult spinalized cats during treadmill walking across a range of relatively slow speeds (0.1 to 1.0 m/s). The effects of increased tactile stimulation or loading on locomotor performance were also studied in the spinal cats. Joint probability density distributions in the spinalized cats showed a low level of MG activation relative to Sol which did not change as speed increased. In general, the coordination between Sol and MG was similar in normal and spinal cats. However, towards the final phase of the extensor burst, the MG EMG amplitude decayed prematurely in spinal cats, particularly at higher speeds. Preferential elevation of MG relative to Sol activity was seen as a result of tactile stimulation. An elevated load resulted in a higher level of MG activation relative to Sol, prolonged MG activity at the end of the extensor burst, and the reduction in the clonic pattern of EMG typical of spinal cats. Spinalized cats showed an increased incidence of Sol-TA coactivation, especially at the higher speeds, due in part to the tonic activity in the TA. However, the overall reciprocal relationship between these antagonists was maintained. This reciprocity was preserved, but the high level of coactivation was unaffected by tactile stimulation. An elevated load, however, resulted in less Sol-TA coactivation. These results suggest that the coordination between synergists (Sol-MG) and between antagonists (Sol-TA and MG-TA), as well as the level of activation are modulated in the adult spinal cat similar to that observed in the normal cat. Further, there are specific types of proprioceptive-cutaneous information that can affect selected phases of the step cycle such that full weight-supporting stepping is significantly improved.

Polar Calcium Flux in Sunflower Hypocotyl Segments : II. The Effect of Segment Orientation, Growth, and Respiration.

Calcium flux in sunflower (Helianthus annuus L. cv Russian mammoth) hypocotyl was measured with a Ca(2+) electrode as the increase or decrease in Ca(2+) in an aqueous solution (10 micromolar CaCl(2)) in contact with either the basal or apical end of 20 millimeter segments. Ca(2+) efflux was significantly higher at the apical end compared with the basal end; this apparent polarity was maintained even when the segments were inverted. No significant difference was observed in the cation exchange capacity of apical and basal cell walls that could explain the difference in Ca(2+) efflux at opposite ends of the hypocotyl segment. The presence of exogenous indoleacetic acid (IAA) in the segment medium resulted in the promotion of both Ca(2+) efflux and segment elongation. However, osmotic inhibition of the IAA-induced elongation did not result in inhibiting the IAA-induced Ca(2+) efflux. Ca(2+) efflux was inhibited by cyanide. Lowering the temperature from 25 degrees C also caused the gradual reduction of Ca(2+) efflux; at 5 degrees C the hypocotyl segments showed a net absorption of Ca(2+) from the segment medium. These findings support the suggestion that: (a) the observed Ca(2+) efflux in hypocotyl segments is probably the manifestation of the system which maintains the transmembrane Ca(2+) gradient at the cellular level. (b) The acropetal polarity of Ca(2+) efflux may be the result of the involvement of Ca(2+) in the basipetal transport of IAA.

Polar calcium flux in sunflower hypocotyl segments : I. The effect of auxin.

The flux of Ca(2+) at the apical or basal ends of short sunflower (Helianthus annuus L.) hypocotyl segments was monitored using a Ca(2+)-specific electrode. A higher Ca(2+) efflux was observed at the apical end relative to the basal end, indicating a net polar flux of Ca(2+). The extreme low mobility of Ca(2+) in the isolated segment makes it likely that the observed Ca(2+) fluxes are of localized origin, that is, from the parenchyma cells close to the exposed cut ends and may represent acropetal transport of Ca(2+) at the cellular level. The rate of Ca(2+) efflux depended on the concentration of Ca in the seedling medium. Incubation of hypocotyl segments in 10 mm CaCl(2) for 24 h did not eliminate the net acropetal flux of Ca(2+) at the apical end.IAA, as well as the synthetic auxin alpha-naphthaleneacetic acid, significantly enhanced Ca(2+) efflux; the non-auxin analog, beta-naphthaleneacetic acid, was ineffective. The transport of auxin, not merely its presence in the medium, was found to be a requisite for the enhancement of Ca(2+) efflux since the presence of the auxin transport inhibitor 2,3,5-triiodobenzoic acid eliminated the auxin-promoted Ca(2+) efflux. A model for how auxin promotion of Ca(2+) efflux could play a role in promoting subsequent auxin secretion is proposed. Calcium probably serves as a ;second messenger', as it does in the secretion of various substances by animal cells.