The physiology of saltwater acclimation in large juvenile Atlantic salmon Salmo salar.

The present study investigated the effects of transferring freshwater (FW) acclimated S. salar (678 g) that had been maintained under a constant photoperiod and thermal regime, into FW (salinity 0) and salt water (SW; salinity 35) on growth and physiological responses over a 28 day period. There were no mortalities observed throughout the study and no significant differences in mass or fork length between FW and SW groups after 28 days. Compared with fish transferred to FW, plasma osmolality and plasma chloride levels increased significantly in fish in SW by day 1. In the SW group, plasma chloride and osmolality had decreased significantly at day 14 when compared with day 1. Na+ -K+ -ATPase activity was significantly higher in SW compared with the FW group from day 7 and thereafter, but continued to increase until day 22. No differences in plasma cortisol and thyroxine were observed between FW and SW groups throughout the study. Plasma glucose significantly increased from day 1 to day 2 in SW but not in the FW group and levels were significantly reduced in SW compared with the FW group at day 28. Plasma cholesterol and triglyceride levels were significantly higher in FW at day 22 and day 14 to day 22, respectively, when compared with the SW group. In the SW group, plasma cholesterol and triglyceride levels did not change significantly throughout the study. The findings of this study suggest that large S. salar retained in FW maintain a high level of SW tolerance in the absence of photoperiod and thermal regimes necessary for smoltification, as demonstrated by 100% survival, unaffected growth performance, increased Na+ -K+ -ATPase activity and a capacity to regulate plasma chloride and osmolality for 28 days in the SW group.

Weight-bearing compared with non-weight-bearing following osteochondral autograft transfer for small defects in weight-bearing areas in the femoral articular cartilage of the knee.

BACKGROUND: Patients are routinely kept non-weight-bearing for four to eight weeks following osteochondral autograft transfer to repair cartilage defects of the medial and/or lateral femoral condyle. Therefore, the objective of this novel study was to investigate whether postoperative weight-bearing restrictions affect the outcomes of cartilage repair when an osteochondral autograft transfer system is used to repair small defects in weight-bearing areas of femoral articular cartilage. METHODS: This a retrospective comparative study. Following review of the charts on 567 consecutive arthroscopic osteochondral autograft transfers, three homogeneous groups of patients with consecutive cases were identified: group A, cases of patients who were non-weight-bearing following the procedure (n = 68); group B, cases of those who were non-weight-bearing following the procedure with concomitant anterior cruciate ligament reconstruction (n = 29); and group C, cases of those who were weight-bearing as tolerated following the procedure (n = 437). The cases of patients whose knees underwent second-look (repeat) arthroscopy were stratified into two subgroups: non-weight-bearing (n = 20) and weight-bearing as tolerated (n = 42). Graft position and manifestation of a repair-adjacent defect (Outerbridge grade-III or IV cartilage defect that develops adjacent to the original osteochondral autograft transfer repair) were assessed during second-look arthroscopy. Cartilage repair was retrospectively assessed from second-look arthroscopy pictures by a blinded, independent orthopaedic surgeon with use of the International Cartilage Repair Society macroscopic cartilage-repair assessment tool. Postoperative complication rates were compared among the three primary groups. RESULTS: The mean grafted area was 0.72 cm(2) (range, 0.16 to 1.45 cm(2)) and 0.73 cm(2) (range, 0.16 to 1.80 cm(2)) for the non-weight-bearing and weight-bearing-as-tolerated second-look subgroups, respectively. The mean International Cartilage Repair Society score was 11.12 and 11.25 points (near-normal cartilage) for the non-weight-bearing and weight-bearing-as-tolerated subgroups (p = 0.71) at a mean follow-up of 42.7 and 33.0 months, respectively. There was no significant difference in the duration of follow-up (p = 0.58), repair-adjacent defect prevalence (p = 0.94), or graft position (p = 0.99) between the two subgroups. Weight-bearing-as-tolerated patients (group C) experienced significantly fewer deep vein thrombosis and arthrofibrosis complications compared with non-weight-bearing patients (groups A and B) (p < 0.001). CONCLUSIONS: Postoperative weight-bearing restrictions did not affect mid-term cartilage repair outcomes in patients who underwent second-look arthroscopy when an osteochondral autograft transfer system was used to repair small defects in weight-bearing areas of cartilage of the medial and/or lateral femoral condyle. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Quality-of-life outcomes with minimally invasive transforaminal lumbar interbody fusion based on long-term analysis of 304 consecutive patients.

STUDY DESIGN: This was a prospective clinical study that took place in an outpatient spine clinic. OBJECTIVE: To demonstrate the short-/long-term outcomes from a large cohort of patients undergoing minimally invasive transforaminal lumbar interbody fusion (MITLIF). SUMMARY OF BACKGROUND DATA: Long-term prospective outcomes in patients undergoing minimally invasive spinal fusion for debilitating back pain has not been well studied. METHODS: Presenting diagnosis was determined from clinical findings and radiographical (radiograph, magnetic resonance image, computed tomographic scan) evaluations preoperatively. Patients were assessed with outcome measures preoperatively, and postoperatively at 2 weeks, 3 months, 6 months, 12 months, 24 months, and annually 2 to 7 years (mean follow-up: 47 mo) final follow-up. The rate of postoperative complications and reoperations at the initial level of MITLIF and adjacent level(s) were followed. Fusion rates were assessed blinded and independently by radiograph. RESULTS: Visual analogue scale scores decreased significantly from 7.0 preoperatively to 3.5 at mean 47-month follow-up. Oswestry Disability Index scores declined from 43.1 preoperatively to 28.2 at mean 47-month follow-up. Short-Form 36 mental component scores increased from 43.8 preoperatively to 49.7 at 47-month follow-up. Short-Form 36 physical component scores increased from 30.6 preoperatively to 39.6 at 47-month follow-up (P < 0.05). CONCLUSION: This prospectively collected outcomes study shows long-term statistically significant clinical outcomes improvement after MITLIF in patients with clinically symptomatic spondylolisthesis and degenerative disc disease with or without stenosis. MITLIF resulted in a high rate of spinal fusion and very low rate of interbody fusion failure and/or adjacent segment disease requiring reoperation while reducing postoperative complications. LEVEL OF EVIDENCE: 3.

Cytokine responses of bovine dendritic cells and T cells following exposure to live or inactivated bovine respiratory syncytial virus.

We compared the effects of live or inactivated bovine respiratory syncytial virus (BRSV) on cytokine production by bovine monocyte-derived dendritic cells (MoDC). We also investigated the response of resting memory CD4(+) T cells to MoDC exposed to both viral preparations. Although BRSV did not appear to replicate in MoDC or to affect expression of major histocompatibility complex (MHC) class I, MHC class II, or CD80/86, a higher percentage of cells exposed to live virus appeared to undergo apoptosis/necrosis. To investigate how the interaction of BRSV with MoDC affects the immune response, a multiplex, real-time, polymerase chain reaction was established to analyze transcription of bovine cytokines. Exposure of MoDC to live BRSV induced more interleukin (IL)-10 mRNA and markedly less IL-12p40 and IL-15 mRNA than did heat-inactivated virus. To determine whether these differences might influence the T cell response, CD4(+) memory T cells primed in vivo were restimulated in vitro by MoDC pulsed with heat-inactivated or live BRSV. Stimulation of CD4(+) T cells induced similar levels of IL-2-and IL-4-like activity and interferon-gamma. These observations suggest that while IL-10, produced by MoDC as a result of exposure to live BRSV, may affect IL-12 and IL-15 synthesis by MoDC, it does not appear to affect the cytokine response of BRSV-specific memory CD4(+) T cells. It is possible, however, that differences in the pattern of cytokines produced by MoDC exposed to live or inactivated virus may influence the development of the primary CD4(+) T cell response in vivo.

Modulation of immune responses to Mycobacterium bovis in cattle depleted of WC1(+) gamma delta T cells.

It is accepted that cell-mediated immune responses predominate in mycobacterial infections. Many studies have shown that CD4(+) T cells produce Th1 cytokines, such as gamma interferon (IFN-gamma), in response to mycobacterial antigens and that the cytolytic activity of CD8(+) cells toward infected macrophages is important. However, the extent and manner in which gamma delta T cells participate in this response remain unclear. In ruminants, gamma delta T cells comprise a major proportion of the peripheral blood mononuclear cell population. We have previously shown that WC1(+) gamma delta T cells are involved early in Mycobacterium bovis infection of cattle, but their specific functions are not well understood. Here we describe an in vivo model of bovine tuberculosis in which the WC1(+) gamma delta T cells were depleted from the peripheral circulation and respiratory tract, by infusion of WC1(+)-specific monoclonal antibody, prior to infection. While no effects on disease pathology were observed in this experiment, results indicate that WC1(+) gamma delta T cells, which become significantly activated (CD25(+)) in the circulation of control calves from 21 days postinfection, may play a role in modulating the developing immune response to M. bovis. WC1(+)-depleted animals exhibited decreased antigen-specific lymphocyte proliferative response, an increased antigen-specific production of interleukin-4, and a lack of specific immunoglobulin G2 antibody. This suggests that WC1(+) gamma delta TCR(+) cells contribute, either directly or indirectly, toward the Th1 bias of the immune response in bovine tuberculosis--a hypothesis supported by the decreased innate production of IFN-gamma, which was observed in WC1(+)-depleted calves.

Susceptibility of calves to challenge with Salmonella typhimurium 4/74 and derivatives harbouring mutations in htrA or purE.

Salmonella typhimurium 4/74 is highly virulent for cattle after oral challenge, causing severe diarrhoea, which is sometimes associated with systemic spread of the micro-organism. Although susceptible to oral challenge, groups of cattle were found to be relatively resistant to subcutaneous challenge with this strain. The virulence of S. typhimurium 4/74 harbouring mutations in htrA and purE was also assessed in cattle. Although S. typhimurium 4/74 htrA and purE are attenuated following oral challenge in mice, cattle were highly susceptible to oral challenge with these mutants. As with the parent S. typhimurium 4/74 strain, cattle exhibited greater susceptibility to oral compared to subcutaneous challenge with S. typhimurium htrA and purE mutants. Following subcutaneous challenge with sublethal levels of S. typhimurium 4/74, calves produced significant levels of antibodies to S. typhimurium soluble extract. No correlation was detected between interferon gamma levels in sera and susceptibility to infection by any route. The concentrations of the acute-phase-associated protein haptoglobin were increased in the sera of five of six cattle inoculated subcutaneously, although increases in concentration were smaller in cattle inoculated orally.