STUDY DESIGN:Lower lumbar vertebral endplates from young and old sand rats were assessed in an Institutional Animal Care and Use Committee approved study for architectural endplate features using micro-computerized tomography (CT) 3-dimensional (3D) models and vascularization studies by an in vivo vascular tracer or immunocytochemical identification of blood vessels. OBJECTIVE:To assess endplate porosity and vascularization using microCT architectural analysis, an in vivo vascular tracer, and immunocytochemical identification of blood vessels in the endplate. SUMMARY OF THE BACKGROUND DATA:The vertebral endplates, also called cartilage endplates, form the superior and inferior, or cranial and caudal, boundaries of the disc. In the human being and sand rat, the cartilaginous endplate undergoes calcification with aging and is replaced by bone. Endplate sclerosis has long been thought to play a role in disc degeneration by decreasing nutrient availability to the disc, but this is still poorly understood. Previous work has identified increasing bone mineral density with aging and disc degeneration in the sand rat model. METHODS:microCT models of the lower lumbar endplates of vertebrae at L5-6 and L6-7 were constructed from 6 younger (mean age 11 months) and 21 older (mean age 25.6 months) sand rats. Architectural features were scored on a semiquantitative scale for smoothness of the endplate face, irregularities on the endplate margin, and endplate thickness. There were 2 smaller sets of animals (n = 18) evaluated for endplate vascularity following in vivo injection of a fluorescent vascular tracer or by the use of immunocytochemistry to identify blood vessels. RESULTS:microCT revealed a solid bony surface to the endplate, which was not penetrated by vasculature; with aging/disc degeneration, there was roughening and pitting of the plate surface, and the development of irregular margins. In L5-6 and L6-7, sites of prominent disc degeneration evident on radiographs, the proportion of abnormalities in surface smoothness, margin irregularity, and endplate thickening were all statistically significant in both younger and older animals (P < or = 0.0027). More severe changes were evident in the caudal versus cranial endplate surfaces. Histologic study of vascular tracer showed that there was no penetration of the disc by vascular supply from the endplate; this was verified by immunocytochemical identification of blood vessels. The canal system within the endplate was a complex 3D interconnected network. CONCLUSIONS:Findings show that disc degeneration in the sand rat occurs concomitantly with marked architectural bony changes on the endplate face, including loss of smoothness and development of irregular bony margins. Vascular connections were not present between the endplate and disc; this was verified with microCT studies, in vivo vascular tracers, and traditional immunocytochemistry. The canal system within the imaged endplate was revealed to consist of a complex 3D interconnected network.

Objective: To determine the optimal approach to prevent adhesions comparing leuprolide acetate (GnRH-a), Interceed (oxidized regenerated cellulose; Johnson & Johnson Medical, Me., New Brunswick, NJ), and a combination of leuprolide with Interceed in a rabbit uterine horn adhesion model.Design: Prospective, randomized, blinded study.Setting: Certified animal care facility.Animal(s): Twenty-eight sexually mature, female New Zealand White rabbits.Intervention(s): Animals were prospectively randomized (by number generator) to receive GnRH-a or saline. After 6 weeks, standard surgical manipulations were performed at three sites in each uterine horn by [1] suture, [2] unipolar cautery, and [3] superficial abrasion. Interceed was applied over one randomly assigned uterine horn only. Six weeks after surgery, uterine adhesions were assessed visually, and tissue fibrosis was assessed by histology.Main Outcome Measure(s): Presence or absence of adhesions and microscopic tissue fibrosis.Result(s): Gonadotropin-releasing hormone agonist significantly decreased adhesions, whereas Interceed alone did not reduce adhesions. However, GnRH agonist plus Interceed was the most effective measure to reduce tissue fibrosis.Conclusion(s): Preoperative GnRH-a is more effective than Interceed in preventing surgical adhesions in the rabbit uterine horn. However, preoperative GnRH-a plus Interceed may provide optimal results in this animal model, because microscopic tissue fibrosis is minimized with this combination. (C) 2004 by American Society for Reproductive Medicine.)

Background and Purpose: Standard treatment for massive hemorrhage in dogs is infusion of whole blood or of packed red blood cells with fresh frozen plasma if whole blood is not available. Although most whole blood is collected using a citrate-based anticoagulant, knowledge of citrate's relevant non-anticoagulant effects is not widespread. Citrate's anticoagulant activity is achieved through chelation of divalent metal cations (e.g., magnesium, calcium), which may exacerbate cardiovascular and metabolic insults attributable to hemorrhage,Methods: Blood pressures, gas tensions, metabolites, and electrolytes; myocardial metabolites, pressures, and contractility; cardiac output; and left cranial descending and circumflex coronary artery flows were measured in 21 anesthetized dogs after hemorrhage was induced by collection of blood into a citrated reservoir to mean arterial pressure of 45 mm Hg for approximately 60 min (until arterial lactate concentration was 7.0 mmol/L), followed by a l-h transfusion and 2 h of maintenance.Results: Arterial ionized calcium concentration, total peripheral resistance, and myocardial function decreased significantly during hemorrhage. All aforementioned responses but myocardial function continued to decrease during the initial 20 min of transfusion, then began to recover. Total peripheral resistance and end-systolic elastance were the only factors significantly related to calcium concentration.Conclusion: Transfusion with citrated whole blood may significantly alter calcium concentration, negatively affecting myocardial and vascular function.

We have investigated the mechanism by which anti-CD28 antibodies activates IFN-gamma production by murine NK cells. These studies reveal that engagement of CD28 alone by this antibody is a poor activator of this cytokine response. Effective stimulation requires simultaneous ligation of the receptor for Fc (FcgammaRIII, CD16) which on its own is also a poor inducer of murine NK cells. The mechanism by which immobilized anti-CD28 increases IFN-gamma mRNA abundance involves both upregulation of transcription as well as induction of mRNA stabilization. However, the elevation of transcription is not as evident as that induced by IL-12 which, in contrast, does not induce message stabilization. Thus ligation of CD28 in the presence of IL-12 results in a synergistic increase in production of the cytokine. Using this assay we have also determined that immobilized anti-CD28 cannot induce resting NK cells to produce IFN-gamma. In contrast, the same cells can be induced by BCL1-C11 tumor cells that express high amounts of the CD28 ligand, B7-2. These studies provide important insights into the ability of cells bearing counter-receptor for CD28 to activate NK cell-cytokine production in vivo.

OBJECTIVEThis study was undertaken to test the hypothesis that hemodialysis with a large-pore membrane would improve heart function during acute endotoxin shock.SETTINGLarge animal laboratory.DESIGNEighteen mongrel dogs were instrumented to measure left ventricular maximum end-systolic elastance (left ventricular maximum elastance at end systole), cardiac output, circumflex artery blood flow, and myocardial mechanical efficiency (CO x MAP/MVO2, where CO is cardiac output, MAP is mean arterial pressure, and MVO2 is myocardial oxygen consumption). Plasma catecholamine concentrations were determined by high-performance liquid chromatography. Endotoxin shock was induced by infusing 5.0 microg/kg/min of Escherichia col 0127:B8 endotoxin in the portal vein for 60 mins, followed by 2.0 microg/kg/min of constant infusion. Control dogs (n = 6) received 4.0 mL/kg/min of saline; hemodialysis dogs (n = 6) underwent venovenous hemodialysis in 50-min intervals using a polysulfone filter (1.2 m2; mean pore size, 0.50 nm; blood flow rate, 400 mL/min; ultrafiltrate, "zero-balanced"); shams (n = 5) were treated identically to hemodialysis dogs, except that no convective dialysis was performed. A fourth group (n = 6) was treated with dopamine (5.0-7.0 microg/kg/min, optimal dose for contractile increase based on dose-response studies).MEASUREMENTS AND MAIN RESULTSAfter 2 hrs of treatment, left ventricular maximum elastance at end systole increased and was unchanged in controls (30 +/- 5 mm Hg/mm) and shams (24 +/- 6 mm Hg/mm) compared with basal control. Hemodialysis treatment increased contractility (53 +/- 4 mm Hg/mm), as did dopamine treatment (54 +/- 7 mm Hg/mm). Endotoxin shock reduced mechanical efficiency to 45% of basal control; with hemodialysis treatment, left ventricular efficiency returned to 64% of basal control measurement, compared with 49% with dopamine treatment. During treatment, myocardial glucose uptake was increased with hemodialysis compared with other groups. No difference was observed among groups for left ventricular end-diastolic pressures or dimensions, or catecholamine concentrations.CONCLUSIONSLarge-pore hemodialysis increased left ventricular contractility to a similar degree as dopamine and provided a marginal improvement in myocardial glucose uptake and mechanical efficiency.

A construct of the Mycoplasma pulmonis (MP) genomic library, using randomly sheared DNA, was cloned in lambda gt11 and transfected into C600 Escherichia coli organisms. Clones of E. coli expressing a fusion protein reactive with anti-MP and monospecific serum were transferred orally or intravenously into Balb/c mice. Expression of the fusion protein was induced by adding isopropyl-beta-D-thiogalactopyranoside to the drinking water. This vaccination protocol led to local and systemic antibody formation, to generation of immune lymphocytes and to protection against large numbers of virulent MP organisms. This approach might be generally successful in preventing infectious disease.

Severe combined immunodeficient (SCID) mice are becoming increasingly popular as research animals; as a consequence, more efforts to produce congenic strains carrying the scid gene are underway. In an attempt to conserve time and resources in this endeavor, we used peripheral blood differential white blood cell counts as a preliminary screen to eliminate the homozygous (+/+) wild type and heterozygous (scid/+) animals from intercross generations. The results of our investigation confirm that blood smears can be used as a screen at four weeks of age to identify animals having an inversion of the granulocyte:mononuclear cell ratio. Mice not having an inversion of this ratio, i.e., mononuclear cells exceeding 50%, can be eliminated from the colony. This screen permits elimination of a large portion of the intercross generation one month earlier than other methods that rely on detection of serum immunoglobulin. The screen is highly sensitive and specific. We do not propose that this screen be used as a definitive test but as a tool to eliminate the majority of animals that are not homozygous at the scid locus.