Tissue engineering aims to overcome the current limitations of heart valves by providing a viable alternative using living tissue. Nevertheless, the valves constructed from either decellularized ...xenogeneic or purely biologic scaffolds are unable to withstand the hemodynamic loads, particularly in the left ventricle. To address this, we have been developing a hybrid tissue-engineered heart valve (H-TEHV) concept consisting of a nondegradable elastomeric scaffold enclosed in a valve-like living tissue constructed from autologous cells. We developed a 21 mm mitral valve scaffold for implantation in an ovine model. Smooth muscle cells/fibroblasts and endothelial cells were extracted, isolated, and expanded from the animal's jugular vein. Next, the scaffold underwent a sequential coating with the sorted cells mixed with collagen type I. The resulting H-TEHV was then implanted into the mitral position of the same sheep through open-heart surgery. Echocardiography scans following the procedure revealed an acceptable valve performance, with no signs of regurgitation. The valve orifice area, measured by planimetry, was 2.9 cm
, the ejection fraction reached 67%, and the mean transmitral pressure gradient was measured at 8.39 mmHg. The animal successfully recovered from anesthesia and was transferred to the vivarium. Upon autopsy, the examination confirmed the integrity of the H-TEHV, with no evidence of tissue dehiscence. The preliminary results from the animal implantation suggest the feasibility of the H-TEHV.
When IVC are directly exhausted from a rodent housing room, the air quality of the room can become independent of the intracage air quality and may reduce the need for high room ventilation rates. ...This study assessed the effect of decreasing the ventilation rate in rodent rooms using
direct-exhaust IVC systems. The study was conducted over 16 wk and compared conditions in 8 rodent rooms that had ventilation rates of 5 to 6 air changes per hour (ACH) with those in rooms at 10 to 12 ACH. At the low ventilation rate, rooms had higher CO2 concentrations, higher
dew point temperature, and lower particulate levels and spent a greater percentage of time above the temperature set point than did rooms at the high rate. The levels of allergens and endotoxins in room air were the same regardless of the ventilation rate. Differences seen in parameters within
cages at the 2 ventilation rates were operationally irrelevant. We detected no total volatile organic compounds in the room that were attributable to ammonia, regardless of the ventilation rate. Clearing the air of ethanol after a spill took longer at the low compared with high rate. However,
ethanol clearance was faster at the low rate when the demand-control system was activated than at the high ventilation rate alone. Air quality in the room and in the cages were acceptable with room ventilation rates of 5 to 6 ACH in rodent rooms that use direct-exhaust IVC systems.
Abstract Histophilus somni causes bovine pneumonia as well as septicemia and its sequelae but mechanisms of virulence and protective immunity are poorly understood. Since surface immunoglobulin ...binding proteins are virulence factors, we addressed their role as protective antigens in a mouse model of H. somni septicemia. Immunoglobulin binding protein A (IbpA), has homology to Bordetella pertussis filamentous hemagglutinin and other large bacterial exoproteins. IbpA is a major surface antigen encoded by the ibpA gene with many domains that may be important in pathogenesis and immune protection. Three IbpA recombinant protein subunits, IbpA3, IbpA5 and IbpADR2 were chosen for study because of putative functional domains and motifs. These recombinant GST fusion subunit proteins were compared with GST (negative control), formalin-killed H. somni (commercial vaccine control), live H. somni (to induce convalescent immunity) and H. somni culture supernatant (containing IbpA shed from the bacterial surface). In vaccination/challenge studies, both live H. somni (convalescent immunity) and supernatant protected equally but formalin-killed H. somni and GST did not protect against septicemia. The DR2 and A3 subunits protected moderately well and induced antibody responses against supernatant antigen and the homologous subunit in ELISA but not against whole cell antigens. Supernatant immunization protected better than the IbpA subunit antigens and induced high antibody activity against both whole cells and supernatant antigens. The results indicate that culture supernatant antigens or perhaps recombinant IbpA subunits may be useful in H. somni vaccines. These studies also provide insight into the contribution of IbpA domains to pathogenesis of H. somni septicemia.
The role of bovine serum or plasma proteins in
Haemophilus somnus virulence was investigated in a mouse model of septicemia. An increase in virulence was detected when the organism was pre-incubated ...for 5
min and inoculated with fetal calf serum. When purified bovine serum or plasma proteins were pre-incubated with
H. somnus before inoculating into mice, transferrin was found to increase virulence. Bovine lactoferrin was also noted to increase virulence, but to a lesser extent and had a delayed time course when compared with transferrin. Using an ELISA assay, an increased amount of
H. somnus whole cells and culture supernatant bound to bovine transferrin when the organism was grown in iron-restricted media. Lactoferrin also bound to
H. somnus, but binding was not affected by growth in iron-restricted media and it was eliminated with 2
M NaCl, which reversed charge mediated binding. Transferrin, but not lactoferrin, supported growth of
H. somnus on iron-depleted agar based media using a disk assay. Therefore, lactoferrin increased virulence by an undetermined mechanism whereas transferrin increased virulence of
H. somnus by binding to iron-regulated outer-membrane proteins (IROMPs) and providing iron to the pathogen.
Histophilus somnicauses bovine pneumonia as well as septicemia and its sequelae but mechanisms of virulence and protective immunity are poorly understood. Since surface immunoglobulin binding ...proteins are virulence factors, we addressed their role as protective antigens in a mouse model ofH. somnisepticemia. Immunoglobulin binding protein A (IbpA), has homology toBordetella pertussisfilamentous hemagglutinin and other large bacterial exoproteins. IbpA is a major surface antigen encoded by theibpAgene with many domains that may be important in pathogenesis and immune protection. Three IbpA recombinant protein subunits, IbpA3, IbpA5 and IbpADR2 were chosen for study because of putative functional domains and motifs. These recombinant GST fusion subunit proteins were compared with GST (negative control), formalin-killedH. somni(commercial vaccine control), liveH. somni(to induce convalescent immunity) andH. somniculture supernatant (containing IbpA shed from the bacterial surface). In vaccination/challenge studies, both liveH. somni(convalescent immunity) and supernatant protected equally but formalin-killedH. somniand GST did not protect against septicemia. The DR2 and A3 subunits protected moderately well and induced antibody responses against supernatant antigen and the homologous subunit in ELISA but not against whole cell antigens. Supernatant immunization protected better than the IbpA subunit antigens and induced high antibody activity against both whole cells and supernatant antigens. The results indicate that culture supernatant antigens or perhaps recombinant IbpA subunits may be useful inH. somnivaccines. These studies also provide insight into the contribution of IbpA domains to pathogenesis ofH. somnisepticemia.
Categorical grading and other measurable MRI parameters are frequently utilised for predicting the outcome of hamstring injuries. However, the reliability and smallest detectable difference (SDD) ...have not been previously evaluated. It therefore remains unclear if the variability in previously reported results reflects reporting variation or actual injury status.
25 hamstring injuries were scored by two experienced radiologists using the Peetrons grading and specific prognostic MRI parameters: distance from ischial tuberosity (cm), extent (cranio to caudal, anterior to posterior, medial to lateral; (cm)), maximum cross-sectional area (%), volume (cm(3)) of the oedema. The interobserver and intraobserver reliability was calculated along with the SDDs for each scale variable.
There were 3 Grade 0 (12%), 11 grade 1 (44%), 9 grade 2 (36%) and 2 grade 3 (8%) injuries. Cronbach's α values for grading were 1.00 (inter) and 0.96 (intra), respectively. The intraclass correlation coefficients for the prognostic MRI parameters were between 0.77 and 1.0. The SDDs varied between each parameter.
Excellent interobserver and intraobserver reliability was found for grading and prognostic MRI parameters in acute hamstring injuries. In daily practice and research, we can be confident that scoring hamstring injuries by experienced radiologists is reproducible. The documented SDDs allow meaningful clinical inferences to be made when assessing observed and reported changes in MRI status.
Background:
Ankle joint injuries are extremely common sports injuries, with the anterior talofibular ligament involved in the majority of ankle sprains. There have been only a few large magnetic ...resonance imaging (MRI) studies on associated structural injuries after ankle sprains.
Purpose:
To describe the injury pattern in athletes who were referred to MRI for the assessment of an acute ankle sprain and to assess the risk of associated traumatic tissue damage including lateral and syndesmotic ligament involvement.
Study Design:
Cross-sectional study; Level of evidence, 3.
Methods:
A total of 261 ankle MRI scans of athletes with acute ankle sprains were evaluated for: lateral and syndesmotic ligament injury; concomitant injuries to the deltoid and spring ligaments and sinus tarsi; peroneal, flexor, and extensor retinacula and tendons; traumatic and nontraumatic osteochondral and osseous changes; and joint effusion. Patients were on average 22.5 years old, and the average time from injury to MRI was 5.7 days. Six exclusive injury patterns were defined based on lateral and syndesmotic ligament involvement. The risk for associated injuries was assessed by logistic regression using ankles with no or only low-grade lateral ligament injuries and no syndesmotic ligament damage as the reference.
Results:
With regard to the injury pattern, there were 103 ankles (39.5%) with complete anterior talofibular ligament disruption and no syndesmotic injury, and 53 ankles (20.3%) had a syndesmotic injury with or without lateral ligament damage. Acute osteochondral lesions of the lateral talar dome were seen in 20 ankles (7.7%). The percentage of chronic lateral osteochondral lesions was 1.1%. The risk for talar bone contusions increased more than 3-fold for ankles with complete lateral ligament ruptures (adjusted odds ratio aOR, 3.43; 95% CI, 1.72-6.85) but not for ankles with syndesmotic involvement. The risk for associated deltoid ligament injuries increased for ankles with complete lateral ligament injuries (aOR, 4.04; 95% CI, 1.99-8.22) compared with patients with no or only low-grade lateral ligament injuries.
Conclusion:
About 20% of athletes referred for MRI after suffering an acute ankle sprain had evidence of a syndesmotic injury regardless of lateral ligament involvement, while more than half had evidence of any lateral ligament injury without syndesmotic involvement. Concomitant talar osseous and deltoid ligament injuries are common.
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