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2.
Traffic Inj Prev ; 10(2): 204-8, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19333835

ABSTRACT

OBJECTIVE: The current study was designed to study hip spica casted and uncasted child dummies in front- and side-impact tests using a variety of restraints. METHODS: Casted one- and three-year-old ATDs were restrained by a traditional child seat, a special hip spica child seat, and the vehicle seat belts. All tests positioned the child upright in either the rear-facing (one-year-old) or forward-facing (three-year-old) direction. One exception was vehicle seat belt tests for the one-year-old, which required the child to be positioned supine due to the position of the child's body imposed by the cast. The ATDs were tested in frontal impacts per FMVSS 213 (delta V of 30 mph) and in side impact using the pulse proposed for 213 (delta V of 20 mph). Corresponding control tests were performed with the uncasted ATDs. The FMVSS 213 mandated injury metrics (HIC36, 3 ms chest gs) and nonmandated due care metrics (HIC15, Nij) were evaluated. RESULTS: For the one-year-old casted tests, 50 percent of the responses increased when compared to the uncasted control. A similar comparison for the three-year-old revealed an 80 percent increase when the dummy was fit with a body cast. HIC36 and chest gs were below the limits established in FMVSS 213 for all casted and uncasted tests. Frontal peak Nij values were in the tension-extension in nine out of ten cases and ranged from 0.8 to 0.83 (uncasted) and 1.02 to 1.92 (casted). Side-impact Nij was approximately 50 percent of the corresponding frontal tests. CONCLUSIONS: The addition of a body cast increases head, neck, and chest responses in front- and side-impact tests. The increases are greatest for the three-year-old who was forward facing.


Subject(s)
Accidents, Traffic , Hip Injuries/prevention & control , Restraint, Physical/instrumentation , Acceleration , Biomechanical Phenomena , Casts, Surgical , Child, Preschool , Hip Injuries/etiology , Humans , Infant , Manikins , Seat Belts , Trauma Severity Indices , United States , Wounds and Injuries/etiology , Wounds and Injuries/prevention & control
3.
Proc Inst Mech Eng H ; 222(6): 865-75, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18935803

ABSTRACT

Current validation tests of total hip arthroplasty endo-prostheses capture only a single activity performed by patients: continuous walking. A more representative test that includes transitions from a static loaded position to dynamic motion would simulate common motions by patients in which they change from standing to walking. The introduction of such transitions into a traditional test protocol could provide insight into actual wear behaviours and more realistic wear particle properties such as size and shape. First, the introduction of transitions will increase the measured wear rate. Second, the amount of wear will be positively correlated to the number of transitions per day. Finally, the size and shape of polyethylene particle produced via testing with transitions will differ from those of a conventional continuous walking test. Three identical sets of four cobalt chromium femoral heads and sterilized acetabular cups sterilized in ethylene oxide were tested in 30 per cent bovine serum under three conditions: continuous walking (0 transitions/day), 10 transitions/day, and 100 transitions/day. A day was defined as 2500 steps. The static and peak dynamic loads were 260 N and 1.9 kN respectively. A testing duration of 106 cycles was completed for each of the three tests. The wear rate was found to be inversely related to the number of transitions. Particle analysis showed that the particle size decreased as the number of transitions increased. Particles from the 100 transitions/day test were more fibular and produced more particles of the size known to promote an immune reactive response. Contrary to our hypothesis, as the number of transitions performed by patients increased, the wear rate and accumulated wear decreased. In addition, as the number of transitions increased, a larger percentage of wear particles were in the submicron size range. Consequently, despite a decrease in wear due to the presence of loading profile transitions, there is a potentially greater risk of osteolysis owing to the increased production of immunoreactive particles.


Subject(s)
Biocompatible Materials/chemistry , Equipment Failure Analysis , Hip Prosthesis , Walking , Weight-Bearing , Humans , Microspheres , Particle Size
4.
Orthopedics ; 31(5): 440, 2008 05.
Article in English | MEDLINE | ID: mdl-19292326

ABSTRACT

This study correlated the frequency of bone bruises with soft tissue injuries in the knee and examined bruise frequency as a function of time postinjury. Magnetic resonance imaging of 1546 patients revealed bone bruises in 19% of patients without an associated meniscal or ligamentous injury. For those patients presenting with at least one meniscoligamentous injury, the frequency of bruising was 60% at 0 to 4 weeks, 42% at 4 to 10 weeks, and 31% at 10 to 26 weeks postinjury. The frequency of bruising varied with the presence of concomitant injuries, with the greatest frequency of bruises (78%) observed in patients with anterior cruciate ligament injuries.


Subject(s)
Contusions/epidemiology , Knee Injuries/epidemiology , Risk Assessment/methods , Soft Tissue Injuries/epidemiology , Adult , Female , Humans , Incidence , Male , Michigan/epidemiology , Retrospective Studies , Risk Factors , Statistics as Topic , Time Factors
5.
Neuropharmacology ; 42(1): 74-81, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11750917

ABSTRACT

The selective 5-HT7 receptor antagonist radioligand, [3H]-SB-269970, has been reported to radiolabel the human cloned 5-HT7(a) receptor and 5-HT7 receptors in guinea pig cortex (thomas et al, 2000). Saturation analysis of [3H]-SB-269970 binding to mouse forebrain, rat cortex, pig cortex, marmoset cortex and human thalamus membranes was consistent with labelling a homogenous population of binding sites in each tissue. K(D) values for [3H]-SB-269970 binding in these tissues ranged from 0.9 to 2.3 nM, being similar to those reported for the human cloned and guinea pig cortex 5-HT7 receptors (1.3 and 1.7 nM, respectively). Bmax values for [3H]-SB-269970 binding to the mouse, rat, pig, marmoset and human brain membranes were 20, 30, 31, 14 and 68 fmoles x mg x protein(-1), respectively. For each species the profile of inhibition of [3H]-SB-269970 binding, using a number of 5-HT7 receptor agonists and antagonists, correlated well with that reported for the human cloned 5-HT7(a) receptor (correlation coefficients were 0.95, 0.94, 0.92, 0.95, 0.97 versus the mouse, rat, pig, marmoset and human tissues, respectively). In conclusion, [3H]-SB-269970 has been shown to radiolabel 5-HT7 receptors in rodent, pig and primate brain and represents a valuable tool with which to further characterise the distribution and function of 5-HT7 receptors in native tissues and elucidate their potential role in disease states.


Subject(s)
Brain Chemistry/drug effects , Phenols , Radiopharmaceuticals , Receptors, Serotonin/drug effects , Serotonin Antagonists , Sulfonamides , Algorithms , Animals , Callithrix , Humans , In Vitro Techniques , Kinetics , Mice , Radioligand Assay , Rats , Species Specificity , Swine
6.
J Orthop Res ; 19(5): 827-33, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11562128

ABSTRACT

Patellofemoral joint impact trauma during car accidents, sporting activities, and falls can produce acute gross fracture of bone, microfracture of bone, and soft tissue injury. Field studies of car accidents, however, show that most patellofemoral traumas are classified as 'subfracture' level injuries. While experimental studies have shown that the influence of flexion angle at impact is not well understood, flexion angle may influence injury location and severity. In the current study, 18 pairs of isolated human cadaver knees were subjected to blunt impact at flexion angles of 60 degrees, 90 degrees, or 120 degrees. One knee from each cadaver was sequentially impacted until gross fracture of bone was produced. The contralateral knee was subjected to a single, subfracture impact at 45% of the impact energy producing fracture in the first knee. The fracture experiments produced gross fracture of the patella and femoral condyles with the fracture plane positioned largely within the region of patellofemoral contact. The fracture location and character changed with flexion angle: at higher flexion angles the proximal pole of the patella and the femoral condyles were more susceptible to injury. For the 90 degrees flexion angle, the patella was fractured centrally, while at 60 degrees the distal pole fractured transversely at the insertion of the patellar tendon. In addition, the load magnitude required to produce fracture increased with flexion angle. In the 'subfracture' knees, injuries were documented for all flexion angles; occult microfractures of the subchondral and trabecular bone and fissures of the articular surface. Similar to the fracture-level experiments, the injuries coincided with the patellofemoral contact region. These data show that knee flexion angle plays an important role in impact related knee trauma. Such data may be useful in the clinical setting, as well as in the design of injury prevention strategies.


Subject(s)
Femur/injuries , Knee Injuries/physiopathology , Patella/injuries , Wounds, Nonpenetrating/physiopathology , Aged , Aged, 80 and over , Cartilage, Articular/injuries , Female , Humans , In Vitro Techniques , Male , Middle Aged , Weight-Bearing
7.
J Biomech Eng ; 123(3): 205-11, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11476362

ABSTRACT

Blunt impact trauma to the patellofemoral joint during car accidents, sporting activities, and falls can produce a range of injuries to the knee joint, including gross bone fracture, soft tissue injury, and/or microinjuries to bone and soft tissue. Currently, the only well-established knee injury criterion applies to knee impacts suffered during car accidents. This criterion is based solely on the peak impact load delivered to seated cadavers having a single knee flexion angle. More recent studies, however, suggest that the injury potential, its location, and the characteristics of the damage are also a function of knee flexion angle and the stiffness of the impacting structure. For example, at low flexion angles, fractures of the distal patella are common with a rigid impact interface, while at high flexion angles splitting of the femoral condyles is more evident. Low stiffness impact surfaces have been previously shown to distribute impact loads over the anterior surface of the patella to help mitigate gross and microscopic injuries in the 90 deg flexed knee. The objective of the current study was to determine if a deformable impact interface would just as effectively mitigate gross and microscopic injuries to the knee at various flexion angles. Paired experiments were conducted on contralateral knees of 18 human cadavers at three flexion angles (60, 90, 120 deg). One knee was subjected to a fracture level impact experiment with a rigid impactor, and the opposite knee was impacted with a deformable interface (3.3 MPa crush strength honeycomb material) to the same load. This (deformable) impact interface was effective at mitigating gross bone fractures at approximately 5 kN at all flexion angles, but the frequency of split fracture of the femoral condyles may not have been significantly reduced at 120 deg flexion. On the other hand, this deformable interface was not effective in mitigating microscopic injuries observed for all knee flexion angles. These new data, in concert with the existing literature, suggest the chosen impact interface was not optimal for knee injury protection in that fracture and other minor injuries were still produced. For example, in 18 cadavers a total of 20 gross fractures and 20 subfracture injuries were produced with a rigid interface and 5 gross fractures and 21 subfracture injuries with the deformable interface selected for the current study. Additional studies will be needed to optimize the knee impact interface for protection against gross and microscopic injuries to the knee.


Subject(s)
Accidents, Traffic , Knee Injuries/physiopathology , Wounds, Nonpenetrating/physiopathology , Aged , Analysis of Variance , Cadaver , Chi-Square Distribution , Female , Femoral Fractures/physiopathology , Femoral Fractures/prevention & control , Humans , Knee Injuries/prevention & control , Male , Wounds, Nonpenetrating/prevention & control
8.
J Biomech Eng ; 123(3): 293-5, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11476374

ABSTRACT

Various impact models have been used to study the injury mechanics of blunt trauma to diarthrodial joints. The current study was designed to study the relationship between impactor energy and mass on impact biomechanics and injury modalities for a specific test condition and protocol. A total of 48 isolated canine knees were impacted once with one of three free flight inertial masses (0.7, 1.5, or 4.8 kg) at one of three energy levels (2, 11, 22 J). Joint impact biomechanics (peak load, loading rate, contact area) generally increased with increasing energy. Injuries were typically more frequent and more severe with the larger mass at each energy level. Histological analyses of the patellae revealed cartilage injuries at low energy with deep injuries in underlying bone at higher energies.


Subject(s)
Cartilage, Articular/injuries , Femur/injuries , Knee Injuries/pathology , Patella/pathology , Wounds, Nonpenetrating/pathology , Animals , Dogs , Trauma Severity Indices , Weight-Bearing/physiology
9.
Am J Vet Res ; 62(3): 414-24, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11277208

ABSTRACT

OBJECTIVE: To examine articular cartilage of the distal interphalangeal (DIP) joint and distal sesamoidean impar ligament (DSIL) as well as the deep digital flexor tendon (DDFT) for adaptive responses to contact stress. SAMPLE POPULATION: Specimens from 21 horses. PROCEDURE: Pressure-sensitive film was inserted between articular surfaces of the DIP joint. The digit was subjected to a load. Finite element models (FEM) were developed from the data. The navicular bone, distal phalanx, and distal attachments of the DSIL and DDFT were examined histologically. RESULTS: Analysis of pressure-sensitive film revealed significant increases in contact area and contact load at dorsiflexion in the joints between the distal phalanx and navicular bone and between the middle phalanx and navicular bone. The FEM results revealed compressive and shear stresses. Histologic evaluation revealed loss of proteoglycans in articular cartilage from older horses (7 to 27 years old). Tidemark advancement (up to 14 tidemarks) was observed in articular cartilage between the distal phalanx and navicular bone in older clinically normal horses. In 2 horses with navicular syndrome, more tidemarks were evident. Clinically normal horses had a progressive increase in proteoglycans in the DSIL and DDFT. CONCLUSIONS AND CLINICAL RELEVANCE: Load on the navicular bone and associated joints was highest during dorsiflexion. This increased load may be responsible for microscopic changes of tidemark advancement and proteoglycan depletion in the articular cartilage and of proteoglycan production in the DSIL and DDFT Such microscopic changes may represent adaptive responses to stresses that may progress and contribute to lameness.


Subject(s)
Cartilage, Articular/physiology , Hoof and Claw/physiology , Horses/physiology , Ligaments, Articular/physiology , Animals , Finite Element Analysis , Forelimb/physiology , Histocytochemistry/veterinary , Joints/physiology , Models, Biological , Stress, Mechanical
10.
Br J Pharmacol ; 130(2): 409-17, 2000 May.
Article in English | MEDLINE | ID: mdl-10807680

ABSTRACT

Binding of the 5-HT(7) receptor antagonist radioligand [(3)H]-SB-269970 to human 5-HT(7(a)) receptors expressed in HEK293 cell membranes (h5-HT(7(a))/293) and to guinea-pig cerebral cortex membranes, was characterized and compared with [(3)H]-5-CT binding. [(3)H]-SB-269970 (1 nM) showed full association with h5-HT(7(a))/293 membranes after 40 min. Specific binding at equilibrium represented >90% of total binding and was fully reversible by methiothepin (10 microM), full dissociation occurring by 100 min. The association (k(+1)) and dissociation (k(-1)) rate constants were 0.05 nM(-1)min(-1) and 0.05 min(-1) respectively, giving a K(D) (k(-1)/k(+1)) of 1.0 nM. [(3)H]-SB-269970 bound saturably and apparently monophasically to both h5-HT(7(a))/293 and guinea-pig cortex membranes, with K(D) values of 1.25+/-0.05 and 1.7+/-0.3 nM respectively. The B(max) for [(3)H]-SB-269970 to both h5-HT(7(a))/293 and guinea-pig cortex membranes (5780+/-380 and 125+/-8.2 fmoles mg protein(-1) respectively) was similar to that for [(3)H]-5-CT (6190+/-940 and 143+/-19 fmoles mg protein(-1) respectively). These data suggest that, in each tissue, both radioligands labelled the same population of receptors, which appear to be present in an agonist high affinity state. The profile of compound inhibition of [(3)H]-SB-269970 binding to h5-HT(7(a))/293 and guineapig cortex membranes correlated well (corr. coeff. 0.98) with those for [(3)H]-5-CT binding and were consistent with the profiles reported previously for the human 5-HT(7(a)) and guinea-pig cortex 5-HT(7) receptors using [(3)H]-5-CT. Hill slopes for inhibition of [(3)H]-SB-269970 and [(3)H]-5-CT binding were close to 1, consistent with binding to a single receptor population in both tissues. [(3)H]-SB-269970 represents the first selective 5-HT(7) antagonist radioligand, which should aid further characterization of 5-HT(7) receptors in recombinant and native tissues and help establish their role in brain function.


Subject(s)
Cerebral Cortex/metabolism , Phenols/pharmacology , Radioligand Assay , Receptors, Serotonin/analysis , Serotonin Antagonists/pharmacology , Sulfonamides/pharmacology , Animals , Binding, Competitive , Cell Membrane/drug effects , Cell Membrane/metabolism , Cerebral Cortex/drug effects , Guinea Pigs , Humans , Kinetics , Ligands , Male , Serotonin/analogs & derivatives , Serotonin/pharmacology , Serotonin Receptor Agonists/pharmacology , Tritium
11.
Biotech Histochem ; 74(1): 27-33, 1999 Jan.
Article in English | MEDLINE | ID: mdl-10190258

ABSTRACT

We compared three histological preparation methods to detect experimentally produced occult microfractures in decalcified human patellae: a paraffin tape-transfer technique, a paraffin slab-cut method, and a paraffin method with methyl salicylate as the clearing agent. Microfractures were observed at the bone-cartilage interface and were oriented either parallel or perpendicular to the tidemark. Both types of microfractures were documented with each preparation method. The slab-cut method was time-consuming, but the section thickness allowed detailed analysis of the architecture of microcracks as they passed into the depth of the section. The methyl salicylate method was efficient and produced thin, serial sections with good morphological detail and minimal cutting artifact. Reliable histological data were also derived from the tape-transfer technique, but this method was inconsistent. The methods summarized here for processing decalcified human joint tissues provide a basis for future orthopaedic studies investigating occult microfractures at the bone-cartilage interface.


Subject(s)
Bone and Bones/pathology , Calcinosis/pathology , Cartilage/pathology , Fractures, Spontaneous/pathology , Adult , Aged , Humans , Knee Joint/ultrastructure , Middle Aged
12.
J Orthop Res ; 17(1): 28-36, 1999 Jan.
Article in English | MEDLINE | ID: mdl-10073644

ABSTRACT

The central third of the patellar tendon is commonly used to reconstruct the injured anterior cruciate ligament. Some studies have noted changes in joint tissues following this procedure. It has been postulated that these changes may be associated with increased stress on the remaining tendon following harvest of the graft. In our study, the central third of the patellar tendon was excised in three groups of rabbits. The central tendon defects in two of the three groups were fitted with different augmentation devices to augment the host tendon during the healing process. All rabbits followed a daily treadmill exercise regimen for 12 weeks following the operation. Biomechanical testing of the tendon revealed that in nonaugmented tendons the cross-sectional area and the length of the patellar tendon significantly increased 112 and 16%, respectively. There was histological evidence of host-tendon remodeling throughout the cross section and extensive fibrosis in the infrapatellar fat pad. Augmentation of the tendon significantly reduced these changes, with the least change noted in the group with the greatest augmentation. The rabbits with augmentation devices retained tendon dimensions similar to those of the contralateral intact tendon, and tendon remodeling occurred only in the defect area. The rabbits with augmentation devices exhibited little to no fibrosis of the fat pad. Structural properties of augmented and nonaugmented tendons were similar despite the size differences, indicating higher tissue quality in the augmented tendons. This study suggested that complications of the knee joint (i.e., tendon proliferation and fat pad fibrosis) noted after anterior cruciate-ligament reconstruction with the autogenous patellar tendon may be limited by the implantation of an augmentation device.


Subject(s)
Knee Joint/surgery , Patella/surgery , Tendons/surgery , Animals , Knee Joint/pathology , Knee Joint/physiopathology , Patella/pathology , Patella/physiopathology , Prostheses and Implants , Prosthesis Implantation , Rabbits , Tendons/pathology , Tendons/physiopathology , Tensile Strength/physiology , Weight-Bearing/physiology
13.
J Biomech ; 31(9): 855-9, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9802787

ABSTRACT

Pressure-sensitive film is frequently used in biomechanics to document intra- and extra-articular contact pressures. This often involves the contact of two surfaces of varying curvature producing non-uniform pressure distributions. The purpose of this study was to determine the feasibility of using multiple films in such experiments to yield accurate pressure and contact area data. A composite arrangement of film was dynamically loaded using cylindrical indenters of five radii. An analytical model of each indentation was constructed to provide a standard for error analysis. The study showed that several ranges of pressure sensitive film can be used simultaneously to accurately transduce contact pressures arising from loading scenarios that produce contact pressure gradients and contact pressures that involve suprathreshold loading of a given film range.


Subject(s)
Biomechanical Phenomena , Diagnostic Imaging/instrumentation , Image Processing, Computer-Assisted , Feasibility Studies , Models, Theoretical , Pressure , Sensitivity and Specificity
14.
J Surg Res ; 79(1): 25-30, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9735236

ABSTRACT

Clinical studies have documented proliferation of the host patellar tendon and fibrosis extending into adjacent tissues after reconstruction of the injured anterior cruciate ligament (ACL) using the central one-third of the patellar tendon (PT) as the graft. Such generalized arthrofibrosis has been implicated in knee locking and as possible source of anterior knee pain. However, it is not clinically feasible to measure changes in tendon morphology and mechanical properties and degeneration of peripheral tissues over time following graft harvest. In a rabbit experimental model proliferative changes in the tendon and the infrapatellar fat pad have been documented following harvest of a central third tendon graft without ACL reconstruction. Studies in larger animals have shown significant reductions in the strength and stiffness of the healing patellar tendon, but without assessment of the peripheral tissue response. In the current study an ACL reconstruction was performed in a goat model using an autogenous patellar tendon graft. Extensive tendon and fat pad proliferation were observed along with significant reductions in the biomechanical properties of the host tendon. Significant fat pad fibrosis was documented using biochemical methods. The current data confirm that harvest of an autogenous PT graft for reconstruction of the ACL results in significant changes in the PT and adjacent tissues. These data may help explain some of the clinical complications documented in the reconstructed joint.


Subject(s)
Anterior Cruciate Ligament/surgery , Patella/pathology , Tendons/pathology , Animals , Anterior Cruciate Ligament Injuries , Biomechanical Phenomena , Female , Goats , Patella/physiology , Tendons/physiology
15.
Arch Dis Child ; 78(4): 373-4, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9623405

ABSTRACT

All enteroviral reports to the Public Health Laboratory Service from 1975 to 1994 which had been proved by culture were analysed. Of the 40,366 isolates, 5741 reports (14%) were from cultures of cerebrospinal fluid. The groups and serotypes accounting for the largest number of cerebrospinal fluid isolates were A9, E7, E9, E11, E19, and E30, accounting for 70% of all cultured isolates of cerebrospinal fluid. It may be possible to prevent most cases of viral meningitis in the UK with the development of an enteroviral vaccine.


Subject(s)
Enterovirus/classification , Meningitis, Viral/virology , Adolescent , Adult , Aged , Child , Child, Preschool , England , Enterovirus/isolation & purification , Female , Humans , Infant , Infant, Newborn , Male , Meningitis, Viral/cerebrospinal fluid , Middle Aged , Serotyping , Wales
16.
J Pharmacol Exp Ther ; 285(2): 553-60, 1998 May.
Article in English | MEDLINE | ID: mdl-9580597

ABSTRACT

Cannabinoid receptors are members of the superfamily of G protein-coupled receptors. Their activation has previously been shown to stimulate guanosine 5'-O-(3-[35S]thio)-triphosphate ([35S]GTP gamma S) binding in a range of brain regions using both membrane preparations and autoradiography. This study evaluates the activities of structurally diverse cannabinoid receptor ligands in the GTP gamma S binding assay, comparing the relationship between receptor binding and activation and also examining efficacy differences between compounds. Using rat cerebellar membrane preparations, the effects of GDP concentration on GTP gamma S binding and the activities of a range of cannabinoid receptor ligands, including the CB1 selective antagonist SR141716A, were investigated. GDP concentration was found to have differing effects on cannabinoid-stimulated [35S]GTP gamma S binding depending on the nature of the agonist used. The stimulation produced by high efficacy compounds, such as CP 55,940 and WIN 55212-2, was increased by raising the GDP concentration, but that of a low efficacy agonist, (-)-delta-tetrahydrocannabinol, was decreased. Of the cannabinoid compounds tested, a wide range of potencies (EC50) and levels of maximal stimulation (Emax) were observed. These ranged from CP 55,244 (Emax of 165, 148-183%, and an EC50 of 0.47, 0.22-0.96, nM) through (-)-delta-tetrahydrocannabinol, cannabinol and anandamide, which produced no concentration-dependent stimulation of [35S]GTP gamma S binding under the same conditions. SR141716A competitively antagonized all the agonists against which it was tested, providing equilibrium dissociation constants (Kd values) in the sub-nanomolar range (0.06-0.40 nM), implicating a CB1 receptor mediated response. These results provide a more detailed characterization of the cannabinoid-stimulated [35S]GTP gamma S binding assay than has previously been reported.


Subject(s)
Cerebellum/metabolism , Guanosine 5'-O-(3-Thiotriphosphate)/metabolism , Receptors, Drug/agonists , Receptors, Drug/antagonists & inhibitors , Animals , Guanosine Diphosphate/pharmacology , Male , Piperidines/pharmacology , Pyrazoles/pharmacology , Rats , Rats, Sprague-Dawley , Receptors, Cannabinoid , Rimonabant
17.
J Foot Ankle Surg ; 37(1): 42-7; discussion 80, 1998.
Article in English | MEDLINE | ID: mdl-9470116

ABSTRACT

Absorbable 1.3-mm polydioxanone (ORTHOSORB) pins were implanted in 75 New Zealand White rabbits in three sites: within the lateral subcutaneous tissue parallel to the femur, down the femoral intramedullary canal, and mediolaterally across the femoral condyles (transcondylar). Pins were harvested at periodic intervals up to 56 and 365 days for mechanical and histologic analyses, respectively. Mechanical analyses were performed by loading the pin in double shear. Histologic analyses were performed on the pin and surrounding tissue. Histologic observations revealed a typical nonspecific foreign-body reaction at all implant sites that resolved at 1 year after resorption of the pin. On histologic examination, there was complete resorption of the pin material in the subcutaneous site by day 182, and there was complete resolution of all response to the pin in six of nine rabbits by day 365. In the intramedullary site, pin material was completely resorbed, based on histologic examination, in five of six rabbits by day 182, and there was complete resolution of the response to the pin in eight of nine rabbits by day 365. The pin material was completely resorbed based on histologic examination of the transcondylar site by day 210, and there was complete resolution of the response to the pin in four of six rabbits by day 270 and in four of nine rabbits by day 365. No enlarged pin tracks or sinus formations were observed in or near the implants sites. The average initial shear strength as 171.4+/ 5.1 MPa, and the breaking strength retention decreased with increasing implantation time. Pins from the subcutaneous regions maintained above 97% of their initial strengths at 28 days, and those from the intramedullary canals maintained above 92%. At later times the strength of the pins implanted in the intramedullary canal decreased more rapidly than those from the subcutaneous region. Overall, the average breaking strength of the subcutaneous pins was significantly greater than that of the intramedullary pins at all time points beyond 14 days. These data indicate that the pins exhibited a strength retention profile sufficient to allow normal healing of bone without enlarged pin tracts, allergic reactions, or sinus formations.


Subject(s)
Bone Nails/adverse effects , Bone Nails/standards , Polydioxanone/adverse effects , Animals , Biomechanical Phenomena , Connective Tissue/pathology , Disease Models, Animal , Female , Femur/pathology , Femur/surgery , Foreign-Body Reaction/etiology , Foreign-Body Reaction/pathology , Humans , Rabbits
18.
J Orthop Res ; 13(6): 936-44, 1995 Nov.
Article in English | MEDLINE | ID: mdl-8544032

ABSTRACT

The current criterion used by the automotive industry for injury to the lower extremity is based on visible bone fracture. Studies suggest, however, that chronic joint degeneration may occur after subfracture impact loads on the knee. We hypothesized that subfracture loading of the patellofemoral joint could result in previously undocumented microtrauma in areas of high contact pressure. In the current study, seven patellofemoral joints from human cadavers were subjected to impact with successively greater energy until visible fracture was noted. Transverse and comminuted fractures of the patella were noted at 6.7 kN of load. Approximately 45% of the impact energy then was delivered to the contralateral joint. Subfracture loads of 5.2 kN resulted in no gross bone fracture in five of seven specimens. Histological examination of the patellae horizontal split fracture in the subchondral bone, at the tidemark, or at the interface of calcified cartilage and subchondral bone. The trauma appeared predominantly on the lateral facet, adjacent to or directly beneath preexisting fibrillation of the articular surface. Surface fibrillation was noted in histological sections of control patellae (not subjected to impact loading), but occult damages were not observed. Although the mechanism of this occult trauma is unknown, similar damage has been shown to occur from direct shear loading. As these microcracks can potentiate a disease process in the joint, this study may suggest that the current criterion for injury, based on bone fracture alone, is not sufficiently conservative.


Subject(s)
Fractures, Bone/pathology , Fractures, Cartilage , Knee Injuries/pathology , Patella/injuries , Wounds, Nonpenetrating/pathology , Acceleration , Adult , Aged , Cadaver , Cartilage/injuries , Female , Femur/injuries , Humans , Male , Middle Aged , Trauma Severity Indices
19.
Vet Rec ; 130(19): 413-6, 1992 May 09.
Article in English | MEDLINE | ID: mdl-1609474

ABSTRACT

Plasma sodium concentrations, packed cell volume, total plasma protein concentration and dermal skinfold thickness were used to assess the state of hydration of 113 transported calves before and after lairage and in 30 control calves on the farm of origin. Skin thickness increased significantly (P less than 0.05) and total protein increased slightly during transport and decreased during lairage. These changes suggest that transport may cause dehydration and lairage may help in recovery. Plasma potassium concentration decreased during transport, but the effect was inversely related to the distance travelled, and the concentration increased during lairage. These changes are consistent with recovery from initially high cortisol levels at loading. The resting behaviour of 150 transported calves was recorded hourly for six hours. More time was spent resting and sleeping by the transported calves than has been reported for non-transported calves and more still by small transported calves, suggesting that transport is exhausting, that lairage helps recovery and that small calves are more adversely affected. During lairage the numbers of calves asleep decreased to values reported for normal calves, suggesting that 10 hours lairage was adequate. However, small calves did not return to their normal rest patterns within the observation period.


Subject(s)
Cattle Diseases/etiology , Dehydration/veterinary , Transportation , Animals , Behavior, Animal , Blood Proteins/analysis , Cattle , Cattle Diseases/blood , Cattle Diseases/prevention & control , Dehydration/blood , Dehydration/etiology , Dehydration/prevention & control , Female , Hematocrit/veterinary , Male , Potassium/blood , Skinfold Thickness , Sleep , Sodium/blood
20.
Ann Rheum Dis ; 46(3): 237-43, 1987 Mar.
Article in English | MEDLINE | ID: mdl-3555359

ABSTRACT

To determine whether an anabolic steroid had any benefit in the treatment of rheumatoid arthritis 47 patients entered a parallel group study. Twenty four received nandrolone decanoate 50 mg intramuscularly every third week for two years and 23 patients received no anabolic steroids. Other therapy was unaltered. Patients attended for clinical and biochemical assessments as well as the objective assessments of elementary body composition by in vivo neutron activation analysis and measurement of the mineral content of the distal femur by single photon absorptiometry on five occasions. A modest clinical deterioration (except for grip strength) was seen in both groups. No significant changes in calcium or alkaline phosphatase were seen. There was no significant change in total body calcium, total body phosphorus, body weight, or bone index/bone width measurements in either group. Significant increases occurred in total body nitrogen, total body potassium, haemoglobin, and packed cell volume (by six months) in the group treated with nandrolone decanoate. Comparison of 10 patients in the group treated with nandrolone decanoate also receiving oral steroid therapy with 14 patients in this group not receiving oral steroid therapy showed no significant differences. The main side effect of nandrolone decanoate was hoarseness. No radiological changes were seen. Nandrolone decanoate, in a dose that produces a significant anabolic effect, has no demonstrable action on bone metabolism in rheumatoid arthritis but may improve the chronic anaemia by six months.


Subject(s)
Anabolic Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Nandrolone/analogs & derivatives , Clinical Trials as Topic , Female , Humans , Menopause , Nandrolone/therapeutic use , Nandrolone Decanoate , Random Allocation
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