Intra-articular pressure profiles of the cadaveric equine fetlock joint in motion

The study of the influence of motion and initial intra-articular pressure (IAP) on intra-articular pressure profiles in equine cadaver metatarsophalangeal (MTP) joints was undertaken as a prelude to in vivo studies, Eleven equine cadaver MTP joints were submitted to 2 motion frequencies of 5 and 10 cycles/min of flexion and extension, simulating the condition of lower and higher (double) rates of passive motion. These frequencies were applied and pressure profiles generated with initial normal intra-articular pressure (-5 mmHg) and subsequently 30 mmHg intra-articular pressure obtained by injection of previously harvested synovial fluid.The 4 trials performed were 1) normal IAP; 5 cyles/min; 2) normal IAP; 10 cycles/min; 3) IAP at 30 mmHg; 5 cycles/min and 4) IAP at 30 mmHg; 10 cycles/min. The range of joint motion applied (mean +/- s.e.) was 67.6 +/- 1.61 degrees with an excursion from 12.2 +/- 1.2 degrees in extension to 56.2 +/- 2.6 degrees in flexion, Mean pressure recorded in mmHg for the first and last min of each trial, respectively, were 1) -5.7 +/- 0.9 and -6.3 +/- 1.1; 2) -5.3 +/- 1.1 and -6.2 +/- 1.1; 3) 58.8 +/- 8.0 and 42.3 +/- 7.2; 4) 56.6 +/- 3.7 and 40.3 +/- 4.6. Statistical analyses showed a trend for difference between the values for the first and last minute in trial 3 (0.05>P<0.1) with P = 0.1 and significant difference (P = 0.02) between the mean IAP of the first and last min in trial 4. The loss of intra-articular pressure associated with time and motion was 10.5, 16.9, 28.1 and 28.9% for trials 1-4, respectively. As initial intraarticular pressure and motion increased, the percent loss of intra-articular pressure increased.The angle of lowest pressure was 12.2 +/- 1.2 (mean +/- s.e.) in extension in trials 1 and 2, In trials 3 and 4, the lowest pressures were obtained in flexion with the joints at 18.5 +/- 2.0 degrees (mean +/- s.e.). This demonstrated that the joint angle of least pressure changed as the initial intra-articular pressure changed and there would not be a single angle of least pressure for a given joint.The volume of synovial fluid recovered from the MTP joints in trial 3 compared to 4 (trials in which fluid was injected to attain IAP of 30 mmHg) was not significantly different, supporting a soft tissue compliance change as a cause for the significant loss of intra-articular pressure during the 15 min of trial 4.The pressure profiles generated correlate well with in vivo values and demonstrated consistent pressure profiles. Our conclusions are summarised as follows:1. Clinically normal equine MTP joints which were frozen and then later thawed were found to have mostly negative baseline intra-articular pressures, as would be expected in living subjects,2. Alternate pressure profiles of the dorsal and plantar pouch at baseline intra-articular pressure document the presence of pressure forces that would support 'back and forth' fluid movement between joint compartments. This should result in movement of joint fluid during motion, assisting in lubrication and nutrition of articular cartilage,3. If joint pressure was initially greater than normal (30 mmHg), as occurs in diseased equine MTP joints, joint motion further increased joint capsule relaxation (compliance) and, therefore, reduced intra-articular pressure.4. Peak intra-articular pressures reached extremely high values (often >100 mmHg) in flexion when initial pressure was 30 mmHg. Joint effusion pressures recorded for clinical MCP joints are frequently 30 mmHg. These IAP values are expected to produce intermittent synovial ischaemia in clinical cases during joint flexion.5, Additional in vivo studies are necessary to confirm our conclusions from this study and to identify the contributions of fluid absorption and the presence of ischaemia in a vascularised joint.

Alterações no líquido sinovial do joelho de cães com osteoartrite induzida pelo modelo Pond e Nuki

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

RADIOGRAFIA E MACROSCOPIA do JOELHO APÓS ESTABILIZAÇÃO EXTRA-ARTICULAR UTILIZANDO FÁSCIA LATA, FIO DE POLIÉSTER TRANÇADO OU FIO DE POLIAMIDA PARA CORREÇÃO da RUPTURA do LIGAMENTO CRUZADO CRANIAL em CÃES

A ruptura do ligamento cruzado cranial é uma das principais doenças ortopédicas que afetam os cães. Muitas técnicas cirúrgicas foram descritas no intuito de aliviar a dor, restaurar a estabilidade biomecânica do joelho e prevenir a progressão da osteoartrite. Fáscia lata, fio de poliéster trançado e fio de poliamida foram empregados na estabilização do joelho após excisão do ligamento cruzado cranial em cães, os quais foram submetidos à avaliação radiográfica e macroscópica da articulação. Neste estudo, foram utilizados 18 cães com massa corporal superior a 15Kg (peso médio - 19,67kg), separados em 3 grupos eqüitativos correspondentes a cada técnica, avaliados durante 30 e 60 dias. Ao exame radiográfico, independentemente de grupo, os cães apresentaram evidência de efusão articular moderada a severa, distensão da cápsula articular e, na maioria dos casos, ausência de sinais de doença articular degenerativa. Ao exame macroscópico da articulação do joelho observou-se espessamento da cápsula articular e tecidos moles periarticulares, erosão da cartilagem articular dos côndilos femorais em todos os grupos e afrouxamento dos fios nos cães submetidos às técnicas de estabilização extra-articular com fio de poliéster trançado e fio de poliamida.

Role of the oblique ligament in the integrity of the medial collateral ligament of the canine elbow joint

Foram estudados o arranjo e o diâmetro médio das fibrilas colágenas do ligamento colateral medial da articulação do cotovelo do cão, isolado ou associado ao ligamento oblíquo e tracionado até a ruptura. Dezoito articulações foram divididas em três grupos. O primeiro grupo teve o ligamento colateral medial coletado, mas não tracionado; o segundo grupo teve o ligamento colateral medial tracionado isoladamente; o terceiro grupo teve os ligamentos colateral medial e oblíquo tracionados associadamente. O ligamento colateral medial não submetido ao ensaio de tração apresentou um padrão ondulado das fibras colágenas, o qual não foi totalmente destruído quando foi tracionado, associado ao ligamento oblíquo, e perdeu totalmente o padrão reticular das fibras colágenas quando testado isoladamente. Quando o ligamento colateral medial foi submetido à tensão isoladamente, o diâmetro médio das fibrilas colágenas aumentou em relação ao grupo não submetido à tensão. Associado ao ligamento oblíquo, o diâmetro médio das fibrilas colágenas foi o maior na região de inserção e o menor na região média, em relação aos outros grupos. Concluiu-se que o ligamento oblíquo pode favorecer a integridade da região de inserção do ligamento colateral medial, aumentando a eficácia de sua reconstrução após a lesão.

Study on the bone mineral density of broiler suffering femoral joint degenerative lesions

An experiment was carried out with male and females broilers of two different commercial breeds to evaluate bone mineral density of the right femur head. A number of 600 one-day-old broilers were raised in an experimental poultry house up to 42 days of age at the School of Veterinary Medicine and Animal Science of UNESP, Botucatu, Brazil. After slaughter, three males and three females in each breed in each of the established gross scores were selected. Their femora heads were submitted to gross examination, and subsequently the thighs were submitted to the Veterinary Hospital for radiographic analysis. Femora were also submitted to bone resistance, Seedor index, and dry matter content analyses. All these bone quality characteristics were different between males and females, independent of breed. Breeds presented similar behavior. It was possible to establish correlations between bone quality parameters, and confidence intervals for bone mineral density values, correlating them to femoral degeneration score, which allows characterizing femoral head lesions by radiographic optical densitometry.

Modeling and Experimental Aspects of Self-healing Bolted Joint through Shape Memory Alloy Actuators

Bolted joints are a form of mechanical coupling largely used in machinery due to their reliability and low cost. Failure of bolted joints can lead to catastrophic events, such as leaking, train derailments, aircraft crashes, etc. Most of these failures occur due to the reduction of the pre-load, induced by mechanical vibration or human errors in the assembly or maintenance process. This article investigates the application of shape memory alloy (SMA) washers as an actuator to increase the pre-load on loosened bolted joints. The application of SMA washer follows a structural health monitoring procedure to identify a damage (reduction in pre-load) occurrence. In this article, a thermo-mechanical model is presented to predict the final pre-load achieved using this kind of actuator, based on the heat input and SMA washer dimension. This model extends and improves on the previous model of Ghorashi and Inman [2004, "Shape Memory Alloy in Tension and Compression and its Application as Clamping Force Actuator in a Bolted Joint: Part 2 - Modeling," J. Intell. Mater. Syst. Struct., 15:589-600], by eliminating the pre-load term related to nut turning making the system more practical. This complete model is a powerful but complex tool to be used by designers. A novel modeling approach for self-healing bolted joints based on curve fitting of experimental data is presented. The article concludes with an experimental application that leads to a change in joint assembly to increase the system reliability, by removing the ceramic washer component. Further research topics are also suggested.

Multiplane ultrasound approach to quantify pleural effusion at the bedside

To assess the accuracy of a multiplane ultrasound approach to measure pleural effusion volume (PEV), considering pleural effusion (PE) extension along the cephalocaudal axis and PE area.Prospective study performed on 58 critically ill patients with 102 PEs. Thoracic drainage was performed in 46 patients (59 PEs) and lung computed tomography (CT) in 24 patients (43 PEs). PE was assessed using bedside lung ultrasound. Adjacent paravertebral intercostal spaces were examined, and ultrasound PEV was calculated by multiplying the paravertebral PE length by its area, measured at half the distance between the apical and caudal limits of the PE.Ultrasound PEV was compared to either the volume of the drained PE (59 PE) or PEV assessed on lung CT (43 PE). In patients with lung CT, the accuracy of this new method was compared to the accuracy of previous methods proposed for PEV measurement. Ultrasound PEV was tightly correlated with drained PEV (r = 0.84, p < 0.001) and with CT PEV (r = 0.90, p < 0.001). The mean biases between ultrasound and actual volumes of PE were -33 ml when compared to drainage (limits of agreement -292 to +227 ml) and -53 ml when compared to CT (limits of agreement -303 to +198 ml). This new method was more accurate than previous methods to measure PEV.Using a multiplane approach increases the accuracy of lung ultrasound to measure the volume of large to small pleural effusions in critically ill patients.

Markers of uremia and pericardial effusion in peritoneal dialysis

Inadequate dialysis causes accumulation of toxic residues that may lead to the development of dialysis-associated pericardial effusion, but several other factors could be associated with this abnormality. The purpose of this study was to evaluate clinical risk factors to asymptomatic pericardial effusion in peritoneal dialysis.This cross-sectional study included 34 patients aged a parts per thousand yen18 years on peritoneal dialysis for at least 3 months, who showed no symptomatic pericardial effusion, hepatic cirrhosis, neoplasias, lupus or amputations, none in minoxidil use. Asymptomatic pericardial effusion was diagnosed by echocardiography. Risk factors were evaluated by logistic regression and Roc curve. Significance level was set at P < 0.05.Patient age was 51 +/- A 15.9 years. of the 34 patients enrolled, 16 were men and 11 diabetic. Five of them presented pericardial effusion. Logistic regression identifies low hemoglobin level (RR 0.454 CI 95%: 0.225-0.913; P = 0.027), low phase angle (RR 0.236 CI 95%: 0.057-0.984; P = 0.048) and low Kt/V (RR 0.001 CI 95%: 0.0-0.492; P = 0.03) as risk factors to pericardial effusion. Roc curve showed that hemoglobin levels below 12.2 g/dL, Kt/V lower than 1.9 and phase angle lower than 4.5A degrees were the best cutoffs to predict pericardial effusion. Four patients showed these three parameters in the unfavorable range, and all these four patients presented pericardial effusion. The other patient with pericardial effusion had two of these parameters reduced.These findings corroborate the hypothesis that uremia plays a significant role in the pathogenesis of dialysis-associated pericardial effusion.

Radiographic measurement of tibial joint angles in sheep

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Radiographic Abnormalities in Barrel Racing Horses with Lameness Referable to the Metacarpophalangeal Joint

Barrel racing is one of the most popular uses of the American Quarter horse in North and South America. Although injury to the metacarpophalangeal joint frequently occurs in this sport, there is limited information describing the nature of these injuries. The aim of this study was to determine the most common radiographic abnormalities in barrel racing horses with lameness referable to the metacarpophalangeal joint. lameness examinations were performed on 63 barrel racing horses. Those found to be lame were subjected to radiographic examination. Lameness at trot was scored on a scale of 0-5 (0 = sound; 5 = inability to move). Data were analyzed using descriptive statistical analysis. of horses examined, 30 (47.6%) were lame with scores ranging from 1 to 4. Half of the lame horses (15 of 30) had grade 2 lameness of the right forelimb. Abnormal radiographic findings were more often present on the left forelimb and included signs of sesamoiditis (70%), villonodular synovitis (56.6%), osteoarthritis (36.6%), osteochondritis dissecans (13.3%), capsulitis (13.3%), and soft-tissue swelling (6.6%). Radiographic abnormalities indicated that sesamoiditis, villonodular synovitis, and osteoarthritis may be associated to mild-to-moderate lameness in barrel racing horses. Complementary sonographic evaluation is recommended to better characterize soft-tissue abnormalities. (C) 2012 Elsevier B.V. All rights reserved.

Origin of sensory and autonomic innervation of the rat temporomandibular joint: A retrograde axonal tracing study with the fluorescent dye fast blue

Previous studies that have used retrograde axonal tracers (horseradish peroxidase alone or conjugated with wheat germ agglutinin) have shown that the temporomandibular joint (TMJ) is supplied with nerve fibers originating mainly from the trigeminal ganglion, in addition to other sensory and sympathetic ganglia. The existence of nerve fibers in the TMJ originating from the trigeminal mesencephalic nucleus is unclear, and the possible innervation by parasympathetic nerve fibers has not been determined. In the present work, the retrograde axonal tracer, fast blue, was used to elucidate these questions and re-evaluated the literature data. The tracer was deposited in the supradiscal articular space of the rat TMJ, and an extensive morphometric analysis was performed of the labeled perikaryal profiles located in sensory and autonomic ganglia. This methodology permitted us to observe labeled small perikaryal profiles in the trigeminal ganglion, clustered mainly in the posterior-lateral region of the dorsal, medial and ventral thirds of horizontal sections, with some located in the anterior-lateral region of the ventral third. Sensory perikarya were also labeled in the dorsal root ganglia from C2 to C5. No labeled perikaryal profiles were found in the trigeminal mesencephalic nucleus. on the other hand, autonomic labeled perikaryal profiles were distributed in the sympathetic superior cervical and stellate ganglia, and parasympathetic otic ganglion. Our results confirmed those of previous studies and also demonstrated that: (i) there is a distribution pattern of labeled perikaryal profiles in the trigeminal ganglion; (ii) some perikaryal profiles located in the otic ganglion were labeled; and (iii) the trigeminal mesencephalic nucleus did not show any retrogradely labeled perikaryal profiles.

PAR(2) and Temporomandibular Joint Inflammation in the Rat

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Putative antinociceptive action of nitric oxide in the caudal part of the spinal trigeminal nucleus during chronic carrageenan-induced arthritis in the rat temporomandibular joint

In order to investigate a putative role for nitric oxide (NO) in the central nociceptive processing following carrageenan-induced arthritis in the rat temporomandibular joint (TMJ), we analyzed the immunoreactivity, gene expression and activity of nitric oxide synthases (NOS) in the caudal part of the spinal trigeminal nucleus (Sp5C) during the acute (24 h), chronic (15 days) and chronic-active (14 days-24 h) arthritis. In addition, evaluation of head-withdrawal threshold was carried out in all phases of arthritis under chronic inhibition of nNOS with the selective inhibitor 7-nitroindazole (7-NI). Neurons with nNOS-like immunoreactivity (nNOS-LI) were concentrated mainly in the lamina II of the Sp5C, showing no significant statistical difference during arthritis. Only a discrete percentage of nNOS-LI neurons expressed Fos immunoreactivity. The mRNA expression for both nNOS and endothelial nitric oxide synthases (eNOS) presented no noticeable differences among the groups. No expression of inducible nitric oxide synthase (iNOS) was detected in the Sp5C by either immunohistochemistry or reverse-transcription polymerase chain reaction (RTPCR). Ca(2+)-dependent NOS activity in the ipsilateral Sp5C was significantly higher (108.3 +/- 49.2%; P<0.01) in animals during the chronic arthritis. Interestingly, this increased activity was completely abolished 24 h later, in the chronic-active arthritis. Finally, head-withdrawal threshold decreased significantly in the chronic arthritis in animals under 7-NI chronic inhibition. In conclusion, nNOS immunoreactivity and mRNA expression are stable in the Sp5C during TMJ arthritis evolution, but its activity significantly increases in the chronic-phases supporting an antinociceptive role of the nNOS as evidenced by pain threshold experiment. (C) 2009 Elsevier B.V. All rights reserved.

Phenotypic alterations of neuropeptide Y and calcitonin gene-related peptide-containing neurons innervating the rat temporomandibular joint during carrageenan-induced arthritis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)