Peripheral vascular surgery: does anesthetic management affect outcome?

Several recent articles have examined the effect of anesthetic technique on outcome in patients undergoing peripheral vascular surgery. This review examines the recent literature and evaluates the role of new data in advancing current understanding of the impact of anesthetic management on outcome in this high-risk population.

Prolonged-fresh preservation of intact whole canine femoral condyles for the potential use as osteochondral allografts.

Defects in articular cartilage are often repaired with fresh osteochondral grafts. While fresh allografts provide viable chondrocytes, logistic limitations require surgical implantation within seven days of graft harvest. Here, we provide information on cold preservation of whole intact osteochondral materials that retains cartilage cell viability and function, and histologic and biochemical integrity for 28 days.

Fibronectin fragments elevate nitric oxide (NO) and inducible NO synthetase (iNOS) levels in bovine cartilage and iNOS inhibitors block fibronectin fragment mediated damage and promote repair.

Objective And Design: To determine whether fibronectin fragments (Fn-f) upregulate nitric oxide (NO) and inducible NO synthetase (iNOS) levels in explants and whether iNOS inhibitors block Fn-f mediated cartilage damage or promote repair.

Material: Bovine cartilage explants were studied.

Treatment: Explants were cultured with Fn-f and involvement of NO pathway investigated.

Effects of perioperative administration of a selective cyclooxygenase 2 inhibitor on pain management and recovery of function after knee replacement: a randomized controlled trial.

Context: Controlling postoperative pain after knee replacement while reducing opioid-induced adverse effects and improving outcomes remains an important challenge.

Objective: To assess the effect of combined preoperative and postoperative administration of a selective inhibitor of cyclooxygenase 2 on opioid consumption and outcomes after total knee arthroplasty (TKA).

Design, Setting, And Patients: Randomized, placebo-controlled, double-blind trial conducted June 2001 through September 2002, enrolling 70 patients aged 40 to 77 years and undergoing TKA at a university hospital in the United States.

Recombinant osteogenic protein-1 upregulates extracellular matrix metabolism by rabbit annulus fibrosus and nucleus pulposus cells cultured in alginate beads.

This study was performed to determine if recombinant human osteogenic protein-1 (rhOP-1) is effective in promoting matrix synthesis and matrix formation by rabbit nucleus pulposus (NP) and annulus fibrosus (AF) cells cultured in alginate beads. The effects of culturing the cells in the presence of various concentrations of rhOP-1 were assessed by measuring changes in cell proliferation, proteoglycan (PG) and collagen synthesis and mRNA expression, and in the matrix contents of PG and collagen, as indicators of matrix accumulation. At high concentrations, rhOP-1 had a moderate mitogenic effect on both NP and AF cells.

Distinguishing ankle and knee articular cartilage.

Degenerative changes in the tall and femoral distal cartilages of more than 2,000 tissue donors were graded based on the appearance of articular cartilage and osteophytes. In the ankle and the knee the degenerative changes increased with age; however, the rate of degeneration in the ankle was slower than in the knee. The degenerative changes in the ankle were more severe in men than in women, were predominantly bilateral, and seemed to be correlated with weight.

Comparison of the catabolic effects of fibronectin fragments in human knee and ankle cartilages.

Objective: To compare the response of knee and ankle cartilages to fibronectin fragments (Fn-f) in terms of kinetics of matrix proteoglycan (PG) degradation and synthesis, since previous data had shown that knee was more sensitive to Fn-f in terms of steady-state PG content.

Design: Human knee and ankle cartilage explants were treated with the 29kDa Fn-f, and its effects on PG-degradation kinetics, on the half-lives of 35S-sulfate-labeled PG, on PG synthesis suppression and on matrix metalloproteinase -3 (MMP-3) were compared. Cultures were also treated with the interleukin (IL) receptor antagonist protein (IRAP) in order to determine whether IL-1 is involved in the Fn-f effect.

Regulation of osteogenic proteins by chondrocytes.

The purpose of this review is to summarize the current scientific knowledge of bone morphogenetic proteins (BMPs) in adult articular cartilage. We specifically focus on adult cartilage, since one of the major potential applications of the members of the BMP family may be a repair of adult tissue after trauma and/or disease. After reviewing cartilage physiology and BMPs, we analyze the data on the role of recombinant BMPs as anabolic agents in tissue formation and restoration in different in vitro and in vivo models following with the endogenous expression of BMPs and factors that regulate their expression.

Spontaneous and experimental osteoarthritis in dog: similarities and differences in proteoglycan levels.

The unilateral canine model is the most commonly used model of experimental osteoarthritis (OA). In this model, the anterior cruciate ligament (ACL) of one knee is transected and the contralateral joint is usually used as a control. However, dogs, similar to humans, can develop OA spontaneously with old age.

High molecular weight hyaluronan promotes repair of IL-1 beta-damaged cartilage explants from both young and old bovines.

Objective: The addition of exogenous high molecular weight hyaluronic acid (HA) reverses cartilage damage caused by fibronectin fragments (Fn-fs) added to explant cultures of bovine and human cartilage and by Fn-fs in an experimental in vivo model of rabbit knee joint damage. Our objective was to test whether HA was also effective in an IL-1 damage model and whether this repair was stable and occurred in older bovine cartilage.

Design: Bovine cartilage explants from 18-month-old or 6-year-old bovines in 10% serum/Dulbecco's modified Eagle's medium were exposed to Fn-f or to IL-1 and the ability of 1mg/ml HA of 800 kDa to block damage or promote restoration of proteoglycan (PG) after the damage was measured.

Effects of IGF-I gene therapy on the injured rat pudendal nerve.

Injured nerves and their motor units may undergo enhanced recovery when exposed to recombinant human insulin-like growth factor-I (rhIGF-I). The external anal sphincter muscle in the female rat was denervated to model incontinence. The treatment-group muscle was injected with rhIGF-1 plasmid, whereas in the control group the plasmid lacked the cDNA insert and the normal group received neither surgery nor treatment.

The use of intra-articular Na-hyaluronate as a potential chondroprotective device in experimentally induced acute articular cartilage injury and repair in rabbits.

Objective: This study examined if viscosupplementation from intra-articular administration of a commercially available form of hyaluronan (HA) could promote the restoration of proteoglycan (PG) depletion induced by chymopapain and then if the repair could be maintained once HA treatment was discontinued.

Methods: Animals received cartilage injury with intra-articular chymopapain (2.0 mg) followed by weekly treatment with intra-articular HA.

The effects of hyaluronic acid on fibronectin fragment mediated cartilage chondrolysis in skeletally mature rabbits.

Objective: Intraarticular Na-Hyaluronate (HA) exerts a beneficial effect on adolescent rabbits after fibronectin fragment (Fn-f) mediated cartilage injury. We extended our studies to a population of rabbits which have reached full skeletal maturity.

Design: Adult male NZW rabbits received an injury with Fn-f and no further treatment; an injection of HA followed by Fn-f injury, or Fn-f injury followed by a single or weekly intraarticular injection of HA.

Fibronectin fragments active in chondrocytic chondrolysis can be chemically cross-linked to the alpha5 integrin receptor subunit.

Objective: To determine whether fibronectin fragments (Fn-f) known to enhance cartilage matrix degradation and to alter chondrocyte metabolism, bind on the chondrocyte cell surface close enough to the alpha(5)beta(1) fibronectin (Fn) receptor to be chemically cross-linked to it.

Design: Biotinylated Fn-fs were added to chondrocytes, followed by cross-linking with dithiobissulfosuccinimidyl propionate, and the resultant alpha(5) complexes trapped on to antialpha(5)-agarose. Adherent material was analysed by probing with avidin-HRP.

Age-related differences in the accumulation and size of hyaluronan in alginate culture.

The alginate bead culture system has unique properties that make it possible to study the accumulation and turnover of macromolecules in two distinct matrix compartments of the cartilage matrix: the cell-associated matrix (CM) and the further removed matrix (FRM). Taking advantage of this culture system, the purpose of this study was to examine age-related changes in the metabolism of hyaluronan (HA) in these two compartments. Bovine chondrocytes, isolated from fetal, young adult, and old adult articular cartilage, were cultured in alginate beads.

Compartmentalization of the matrix formed by nucleus pulposus and annulus fibrosus cells in alginate gel.

Intervertebral disc cells cultured in alginate gel are capable of reforming in alginate, a matrix that consists of two compartments: a rim of metabolically active cell-associated matrix and a more abundant, but metabolically less active, further removed matrix. At any one age and in most species, the cell-associated matrix formed by a nucleus pulposus or annulus fibrosus cell cultured in this way is less abundant than that formed by an articular chondrocyte. In both the cell-associated matrix and further removed matrix, the ratio of aggrecan to collagen is significantly higher in the case of nucleus pulposus than of annulus fibrosus, a feature that also distinguishes the matrices of the nucleus pulposus and annulus fibrosus in vivo.

Matrix homeostasis in aging normal human ankle cartilage.

Objective: To study age-related (as opposed to arthritis-related) changes in collagen and proteoglycan turnover.

Methods: Macroscopically nondegenerate normal ankle cartilage obtained from 30 donors (ages 16-75 years) was processed for in situ hybridization to detect messenger RNA (mRNA) of type IIB collagen (CIIB); antibodies to the C-propeptide of type II collagen (CPII), to the type II collagen (CII) collagenase-generated cleavage neoepitope (Col2-3/4C(short)), and to the CII denaturation product (Col2-3/4m) were used for immunohistochemistry analysis and immunoassay. In addition, immunoblotting was used to detect the 4 collagenases.

Changes in mRNA and protein levels of proteoglycans of the anulus fibrosus and nucleus pulposus during intervertebral disc degeneration.

Study Design: This study correlates the mRNA and protein levels of large and small proteoglycans with the morphologic grade of degeneration.

Objectives: To investigate changes in mRNA and protein levels of aggrecan, versican, biglycan, decorin and fibromodulin in the anulus fibrosus and the nucleus pulposus at different stages of tissue degeneration.

Summary Of Background Data: Proteoglycans are found in both the anulus fibrosus and nucleus pulposus and contribute to the hydration of the tissue (aggrecan) and the regulation of matrix assembly (small proteoglycans).

Cyclooxygenase-2 inhibition potentiates morphine antinociception at the spinal level in a postoperative pain model.

Background And Objectives: After peripheral inflammatory stimuli, spinal cord cyclooyxgenase-2 (COX-2) mRNA and protein levels increase, whereas COX-1 is unchanged. In animal models of inflammatory pain, intrathecal COX-2 selective inhibitors suppress hyperalgesia. However, the role of spinal COX-2 inhibition in postoperative pain is not well elucidated.

Fibronectin fragments upregulate insulin-like growth factor binding proteins in chondrocytes.

Unlabelled: Addition of fibronectin fragments (Fn-fs) to cultured cartilage explants has been shown to mediate extensive cartilage matrix degradation followed by anabolic responses.

Objective: To determine whether specific Fn-fs regulate cartilage metabolism through a mechanism, in part, involving insulin-like growth factor (IGF) and insulin-like growth factor binding proteins (IGFBPs).

Methods: Primary bovine articular chondrocyte cultures were treated with Fn-fs.

Intrathecal magnesium prolongs fentanyl analgesia: a prospective, randomized, controlled trial.

Unlabelled: Magnesium is a noncompetitive, N-methyl-D-aspartate receptor antagonist that does not effectively cross the blood-brain barrier when given IV. Intrathecal magnesium potentiates opioid antinociception in rats, and the safety of intrathecal magnesium has been demonstrated in animals. This is the first prospective human study evaluating whether intrathecal magnesium could prolong spinal opioid analgesia.

Cutting edge: regulation of T cell activation threshold by CD28 costimulation through targeting Cbl-b for ubiquitination.

Optimal T cell activation requires signaling through the TCR and CD28 costimulatory receptor. CD28 costimulation is believed to set the threshold for T cell activation. Recently, Cbl-b, a ubiquitin ligase, has been shown to negatively regulate CD28-dependent T cell activation.

The mechanisms of intracranial pressure modulation by epidural blood and other injectates in a postdural puncture rat model.

Unlabelled: The epidural blood patch is considered effective in treating postdural puncture headache. We have developed a postdural puncture model in rats for quantitative evaluation of the magnitude and duration of changes in cerebrospinal fluid (CSF) pressure in the cisterna magna in response to the administration of epidural blood or other moieties. This model was used to compare the efficacy of various methods of epidural injection for restoring and maintaining CSF pressure for up to 240 min.

Osteogenic protein-1 enhances matrix replenishment by intervertebral disc cells previously exposed to interleukin-1.

Study Design: A study of the mechanisms involved in matrix repair by intervertebral disc cells cultured in alginate gel was performed.

Objectives: To determine the effects of osteogenic protein-1 on the extracellular matrix of intervertebral disc cells previously exposed to interleukin-1, which is an in vitro model for degraded extracellular matrix.

Summary Of Background Data: Disc degeneration is accompanied by a decrease in the content of negatively charged proteoglycans in the matrix.