Preliminary evaluation of a hydrogel liquid bandage in 30 dogs undergoing tibial plateau levelling osteotomy surgery.

AIMS: To compare the prevalence of minor incisional complications in canine patients undergoing tibial plateau levelling osteotomy (TPLO) surgery that had a hydrogel liquid bandage (HLB) applied to their incision, with patients that had a light adhesive bandage applied. METHODS: Thirty dogs undergoing TPLO surgery were randomly assigned to either application of a light adhesive bandage to the incision, with removal 18-24 hours later, or application of a clear-drying polyethylene glycol HLB to the incision. Erythema, swelling, discharge, and dehiscence were assessed 1 day (Day 1) and 10-14 days (Days 10-14) postoperatively. All persons completing the assessment were blinded to the treatment. Outcomes were compared for the two groups using Fisher's Exact Test. RESULTS: On both Day 1 and Days 10-14, the distribution of dogs with erthemyma or swelling did not differ between the two groups (p≥0.4). The prevalence of erythema was the same in the bandage and HLB groups at Day 1 (11/15; 73%) and was similar at Days 10-14 (3/11 (27%) and 2/11 (18%), respectively). Prevalence of swelling was also the same in the two groups on Day 1 (11/15; 73%) and was similar at Days 10-14 (3/11 (27%) and 6/11 (55%), respectively). On Day 1, 2/15 (13%) dogs in the HLB group and none of the dogs in the bandage group had incisional discharge (p=0.483). No dogs were observed with discharge on Days 10-14. No dehiscence, infection, or any other major incisional complication was observed in either group at any point in the study. CONCLUSIONS: Preliminary results suggest that prevalence of minor incisional complications after TPLO surgery treated with HLB or with a traditional adhesive bandage may be comparable. No major adverse effects were seen with the use of HLB. CLINICIAL RELEVANCE: Due to several disadvantages of traditional bandaging, which can require post-operative maintenance and removal, lasts only a short time, and be painful when removed, an alternative with fewer drawbacks is desirable. HLB may present such an alternative.

Pten and p53 converge on c-Myc to control differentiation, self-renewal, and transformation of normal and neoplastic stem cells in glioblastoma.

Glioblastoma (GBM) is a highly lethal primary brain cancer with hallmark features of diffuse invasion, intense apoptosis resistance and florid necrosis, robust angiogenesis, and an immature profile with developmental plasticity. In the course of assessing the developmental consequences of central nervous system (CNS)-specific deletion of p53 and Pten, we observed a penetrant acute-onset malignant glioma phenotype with striking clinical, pathological, and molecular resemblance to primary GBM in humans. This primary, as opposed to secondary, GBM presentation in the mouse prompted genetic analysis of human primary GBM samples that revealed combined p53 and Pten mutations as the most common tumor suppressor defects in primary GBM. On the mechanistic level, the "multiforme" histopathological presentation and immature differentiation marker profile of the murine tumors motivated transcriptomic promoter-binding element and functional studies of neural stem cells (NSCs), which revealed that dual, but not singular, inactivation of p53 and Pten promotes cellular c-Myc activation. This increased c-Myc activity is associated not only with impaired differentiation, enhanced self-renewal capacity of NSCs, and tumor-initiating cells (TICs), but also with maintenance of TIC tumorigenic potential. Together, these murine studies have provided a highly faithful model of primary GBM, revealed a common tumor suppressor mutational pattern in human disease, and established c-Myc as a key component of p53 and Pten cooperative actions in the regulation of normal and malignant stem/progenitor cell differentiation, self-renewal, and tumorigenic potential.

Controlling blepharospasm effect during applanation tonometry using the Volk SuperField Lid Lens Adapter.

PURPOSE: To describe a practical clinical technique that can be used to control the effect of blepharospasm during applanation tonometry. METHODS: The Volk Superfield NC Lid Lens Adapter is used to keep the eye open and prevent the squeezing effect of orbicularis oculi in blepharospasm. RESULTS: This helpful tool can be used when blepharospasm becomes a problem that interferes with accurate intraocular pressure measurement. CONCLUSIONS: The technique is potentially useful and relatively easy to perform.

Mechanomyographic and electromyographic amplitude and frequency responses from the superficial quadriceps femoris muscles during maximal, eccentric isokinetic muscle actions.

The purposes of this study were to examine the effects of gender and muscle (vastus lateralis = VL, rectus femoris = RF, and vastus medialis = VM) on the velocity-related patterns for peak torque (PT), mean power output (MP), mechanomyographic (MMG) amplitude, electromyographic (EMG) amplitude, MMG mean power frequency (MPF), and EMG MPF during maximal, eccentric isokinetic muscle actions. Thirteen females (mean +/- SD age = 21 +/- 1 years) and eleven males (mean +/- SD age = 21 +/- 2 years) volunteered for this investigation. PT and MP were measured on a calibrated Cybex 6000 dynamometer at randomly ordered velocities of 60, 120, and 180 degrees.s-1, while MMG and EMG signals were recorded simultaneously from the VL, RF, and VM muscles. The results indicated no gender-related differences for the patterns of PT, MP, MMG amplitude, EMG amplitude, MMG MPF, or EMG MPF. Furthermore, no muscle-related differences were found for the patterns of MMG amplitude, EMG amplitude, or MMG MPF. The normalized values for MP and MMG amplitude increased from 60 to 180 degrees.s-1 (60 degrees.s-1 < 120 degrees.s-1 < 180 degrees.s-1). PT and EMG MPF remained unchanged across velocity, while EMG amplitude remained unchanged from 60 to 120 degrees.s-1, but decreased (approximately 10%) from 120 to 180 degrees.s-1. The findings indicated a close association between the patterns for MP and MMG amplitude, and a similarity between the patterns for PT, EMG amplitude, and EMG MPF across velocity. Therefore, the present findings suggested that motor unit recruitment (EMG amplitude), firing rate (MMG MPF), and muscle fiber action potential conduction velocity (EMG MPF) exhibited velocity-related patterns that were similar to PT production, while MMG amplitude was more closely associated with MP.

Heart rate and ratings of perceived exertion at the physical working capacity at the heart rate threshold.

The purpose of this investigation was to examine the heart rate (HR) responses and ratings of perceived exertion (RPE) during continuous work bouts at 80, 100, and 120% of the physical working capacity at the heart rate threshold (PWCHRT). Ten men (mean age +/- SD = 23.3 +/- 2.9 years) performed a maximal cycle ergometer test and four, 8-minute submaximal work bouts for the determination of PWCHRT. Each subject then performed 3 continuous 1-hour work bouts at 80, 100, and 120% of the power output corresponding to PWCHRT. The results of the 1-hour work bouts showed that slope coefficients for the mean HR vs. time relationships for all 3 power outputs were significantly (p < 0.05) greater than zero and 0.1 bpm x min(-1). In addition, the slope coefficients for mean RPE vs. time relationships for all 3 power outputs were significantly (p < 0.05) greater than zero. The mean slope coefficients for the HR and RPE vs. time relationships indicated that the PWCHRT test overestimated the maximal power output associated with steady-state HR and RPE responses. The mean HR slope coefficient suggested, however, that the PWCHRT could be maintained for over 4 hours.

Mean power frequency and amplitude of the mechanomyographic and electromyographic signals during incremental cycle ergometry.

The purpose of this investigation was to determine the relationships for mechanomyographic (MMG) amplitude, MMG mean power frequency (MPF), electromyographic (EMG) amplitude, and EMG MPF versus power output during incremental cycle ergometry. Seventeen adults volunteered to perform an incremental test to exhaustion on a cycle ergometer. The test began at 50 W and the power output was increased by 30 W every 2 min until the subject could no longer maintain 70 rev min(-1). The MMG and EMG signals were recorded simultaneously from the vastus lateralis during the final 10 s of each power output and analyzed. MMG amplitude, MMG MPF, EMG amplitude, EMG MPF, and power output were normalized as a percentage of the maximal value from the cycle ergometer test. Polynomial regression analyses indicated that MMG amplitude increased (P<0.05) linearly across power output, but there was no change (P>0.05) in MMG MPF. EMG amplitude and MPF were fit best (P<0.05) with quadratic models. These results demonstrated dissociations among the time and frequency domains of MMG and EMG signals, which may provide information about motor control strategies during incremental cycle ergometry. The patterns for amplitude and frequency of the MMG signal may be useful for examining the relationship between motor-unit recruitment and firing rate during dynamic tasks.

Mechanomyography, electromyography, heart rate, and ratings of perceived exertion during incremental cycle ergometry.

BACKGROUND: The purpose of this investigation was to examine the relationships of mchanomyography (MMG), electromyography (EMG), heart rate (HR), and ratings of perceived exertion (RPE) versus power output during incremental cycle ergometry. METHODS: Nine adult males [mean (+/-SD) age 23 (+/-3) years] volunteered to perform an incremental test to exhaustion on a cycle ergometer. The MMG, EMG, HR, and RPE values were recorded at the end of each power output. RESULTS: The normalized (expressed as a percentage of maximal values) relationships for MMG, HR, and RPE versus power output were linear, while the EMG versus power output relationship was quadratic. Furthermore, there were no significant (p > 0.10) differences between slope coefficients for the relationships among MMG, HR, and RPE versus power output. CONCLUSIONS: The results of this investigation indicated that there were close associations among the mechanical (MMG), cardiac (HR), and perception of effort (RPE) aspects of cycle ergometry. In addition, there was a dissociation between the linear MMG pattern and quadratic EMG pattern with increasing power outputs.

Mechanomyographic responses to continuous, constant power output cycle ergometry.

PURPOSE: The purpose of the present investigation was to examine the mechanomyographic (MMG) and electromyographic (EMG) responses to continuous, constant power output cycle ergometer workbouts. METHODS: Eight adult male volunteers (mean age +/- SD = 22 +/- 2 yrs) performed three continuous, one-hour workbouts at 28, 35, and 42% of peak power (Ppeak). RESULTS: The slope coefficients for the mean normalized MMG amplitude versus time relationships were significantly (p < 0.05) less than zero, while the slope coefficients for the mean normalized EMG amplitude versus time relationships were significantly (p < 0.05) greater than zero. CONCLUSION: The results indicated dissociation between the patterns of the mechanical (MMG) and electrical (EMG) activity of the vastus lateralis during continuous cycle ergometry at low power outputs. The increases in EMG amplitude were likely due to the recruitment of additional motor units. The decreases in MMG amplitude across time may have been due to the phenomenon known as "muscular wisdom" and/or decreases in muscular compliance.

Mechanomyographic amplitude and mean power output during maximal, concentric, isokinetic muscle actions.

The purpose of this study was to determine the velocity-related patterns for mechanomyographic (MMG) amplitude, electromyographic (EMG) amplitude, mean power output (MP), and peak torque (PT) of the superficial muscles of the quadriceps femoris (vastus lateralis [VL], rectus femoris [RF], and vastus medialis [VM]) during maximal, concentric, isokinetic leg extensions. Twelve adult women (mean +/- SD: 22 +/- 3 years of age) performed such leg extensions at velocities of 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 300 degrees /s on a Cybex 6000 dynamometer. PT decreased (P < 0.05) across velocity to 240 degrees /s. MP and MMG amplitude for each muscle (VL, RF, and VM) increased (P < 0.05) with velocity to 240 degrees /s and then plateaued. EMG amplitude increased (P < 0.05) to 240°/s for the VL, remained unchanged across velocity (P > 0.05) for the RF, and increased (P < 0.05) to 300 degrees /s for the VM. The results indicated close similarities between the velocity-related patterns for MMG amplitude and MP, but dissociations among EMG amplitude, MMG amplitude, and PT. These findings support the recent hypothesis that MMG amplitude is more closely related to MP than PT during maximal, concentric, isokinetic muscle actions and, therefore, may be useful for monitoring training-induced changes in muscle power.

Electromyographic and mechanomyographic responses.

The purpose of the present study was to determine the electromyographic (EMG) and mechanomyographic (MMG) responses to cycle ergometry at critical power (CP). Seven moderately active males (25 +/- 3 years) completed a 60-min trial at their CP estimated from a nonlinear, 3 parameter regression model. EMG and MMG amplitudes were recorded from the vastus lateralis during 60-min continuous rides at CP. The mean CP was 175 +/- 25 W, which represented 56 +/- 5% of the subjects' peak power outputs. The results indicated that the slope coefficient for the EMG amplitude versus time relationship was not significantly different from zero; however, MMG amplitude decreased significantly over the 60 min. This dissociation between the electrical (EMG) and mechanical (MMG) aspects of muscular activity during cycle ergometry may be due to neuromuscular changes associated with "muscle wisdom" or changes in muscular compliance.

Effect of mathematical modeling on the estimation of critical power.

PURPOSE: The purposes of this study were to re-examine the findings of previous studies by comparing the critical power (CP) estimates from five mathematical models and to determine the time to exhaustion during cycle ergometry at the lowest CP estimate from the five models. METHODS: Nine adult males performed a maximal incremental test to determine peak power and five or six randomly ordered trials on a cycle ergometer for the estimation of CP. Two linear, two nonlinear, and one exponential mathematical model were used to estimate CP. The subjects then completed two trials to exhaustion, or 60 min, at their lowest estimate of CP from the five models. RESULTS: The nonlinear three-parameter model (Nonlinear-3) produced a mean CP that was significantly (P < 0.05) less than the mean CP values derived from the other four models and was the lowest CP estimate for each subject. Two and three subjects, however, did not complete 60 min of cycling during the first and second trials at CP, respectively. At the end of the trials the subjects who completed 60 min of cycling had a mean heart rate of 92% of their maximum and a mean rating of perceived exertion of 17. CONCLUSION: These findings support previous studies that have indicated that in many cases CP overestimates the power output that can be maintained for at least 60 min.

Mechanomyographic and electromyographic responses during submaximal cycle ergometry.

The purpose of this study was to examine the mechanomyographic (MMG) and electromyographic (EMG) responses during continuous, cycle ergometer workbouts performed at constant power outputs. Eight adults [mean (SD) age, 21.5 (1.6) years] volunteered to perform an incremental test to exhaustion for the determination of peak power (Wpeak) and four, 15-min (or to exhaustion) rides at constant power outputs of 50%, 65%, 80%, and 95% Wpeak. Piezoelectric crystal contact sensors were placed on the vastus lateralis (VL) and vastus medialis (VM) muscles to record the MMG signals. Bipolar surface electrode arrangements were placed on the VL and VM to record the EMG signals. Five-second samples of the MMG and EMG signals were recorded every 30 s at power outputs of 50%, 65%, and 80% Wpeak, and every 15 s at 95% Wpeak. The amplitudes of the selected portions of the signals were normalized to the first values recorded during the continuous rides, and regression analyses were used to determine whether the slope coefficients for the MMG and EMG versus time relationships were significantly (P < 0.05) different from zero. The results indicate that EMG amplitude increased (range of slope coefficients: 0.03-0.56) during the continuous rides for both muscles at all four power outputs (except the VM at 50% Wpeak), while MMG amplitude increased (slope coefficient at 95% Wpeak for VM = 0.19), decreased (range of slope coefficients for VL and VM at 50% and 65% Wpeak = -0.14 to -0.24), or remained unchanged (range of slope coefficients for VL and VM at 80% Wpeak and VL at 95% peak = -0.06 to 0.12) depending on the power output. The patterns of the MMG responses, however, were similar for the VL and VM muscles, except at 95% Wpeak. Fatigue-induced changes in motor-unit recruitment and discharge rates, or muscular compliance may explain the differences between power outputs in the patterns of the MMG amplitude responses.

MMG and EMG responses of the superficial quadriceps femoris muscles.

Eighteen adults performed isometric muscle actions of the leg extensors at 25, 50, 75, and 100% maximal voluntary contraction (%MVC) at leg flexion angles of 25, 50, and 75 degrees. The results indicated that isometric torque production increased as leg flexion angle increased (75 degrees > 50 degrees > 25 degrees). For each muscle tested (rectus femoris, vastus lateralis, and vastus medialis), the EMG amplitude increased up to 100%MVC at each leg flexion angle (25, 50, and 75 degrees). The MMG amplitude for each muscle, however, increased up to 100%MVC at 25 and 50 degrees of leg flexion, but plateaued from 75 to 100%MVC at 75 degrees of leg flexion. We hypothesize that the varied patterns for the MMG amplitude-isometric torque relationships were due to leg flexion angle differences in: (1) muscle stiffness, (2) intramuscular fluid pressure, or (3) motor unit firing frequency.

Gender comparisons of the mechanomyographic responses to maximal concentric and eccentric isokinetic muscle actions.

PURPOSE: The purpose of this study was to determine whether there is a gender difference in the velocity-related patterns of mechanomyographic (MMG) responses to maximal isokinetic concentric (CON) and eccentric (ECC) muscle actions. METHODS: Adult males (N = 15) and females (N = 16) performed maximal CON and ECC muscle actions of the leg extensors on a calibrated Cybex 6000 dynamometer at velocities of 30, 90, and 150 degrees.s-1. MMG was detected by a piezoelectric crystal contact sensor placed over the vastus lateralis muscle. RESULTS: The results indicated that there were decreases in CON peak torque (PT) across velocities, while ECC PT remained constant with increasing velocity for both genders. MMG amplitude increased significantly (P < 0.05) with velocity in both the males and females for CON and ECC muscle actions. There was a gender difference in the velocity-related patterns of MMG responses to maximal isokinetic CON muscle actions; however, there was no gender difference in the pattern of ECC MMG responses. CONCLUSIONS: The gender difference in CON MMG responses may be attributed to the greater percent decline in CON PT across velocity for the females than the males. In addition, the males displayed greater CON and ECC MMG amplitudes at all muscle action velocities than the females, possibly because of gender differences in muscle mass and/or thickness of the adipose tissue layer.

Mechanomyographic and electromyographic responses to eccentric and concentric isokinetic muscle actions of the biceps brachii.

The purpose of the present investigation was to examine the effects of forearm angular velocity on the mechanomyographic (MMG) and electromyographic (EMG) responses to eccentric and concentric isokinetic muscle actions. Ten adult male volunteers (mean+/-SD age=23+/-2 years) performed maximal eccentric and concentric muscle actions of the forearm flexors at 30 degrees, 90 degrees, and 150 degrees s(-1). There was no significant (P> 0.05) velocity-related change in peak torque (PT) for the eccentric muscle actions, but there was a significant (P < 0.05) decrease in PT for the concentric muscle actions. For the eccentric and concentric muscle actions, there was a significant (P< 0.05) velocity-related increase in MMG amplitude. There was no significant (P < 0.05) change in EMG amplitude across velocity for the eccentric or concentric muscle actions. The results indicated velocity-related dissociations among the PT, MMG, and EMG responses to maximal eccentric and concentric isokinetic muscle actions.

The effect of leg flexion angle on the mechanomyographic responses to isometric muscle actions.

The purpose of this investigation was to examine the effect of leg flexion angle on the relationship between mechanomyographic (MMG) amplitude and isometric torque production. Adult males (n = 9) performed isometric muscle actions of the leg extensors at 25, 50, 75, and 100 percent maximal voluntary contraction (%MVC) on a calibrated CYBEX 6000 dynamometer at 25, 50, and 75 degrees below full extension. A piezoelectric MMG recording device was placed over the mid-portion of the rectus femoris. At 25 degrees of leg flexion, the MMG amplitude increased to 100%MVC. At 50 and 75 degrees of leg flexion, however, MMG amplitude increased to 75%MVC, and then did not change significantly (P > 0.05) between 75 and 100%MVC. These findings indicate that the MMG amplitude-isometric torque relationship is joint angle specific and may be the result of leg flexion angle differences in: (1) muscle stiffness, or (2) motor unit activation strategies.

The clinical and pathologic constellation of Wegener granulomatosis of the orbit.

PURPOSE: Wegener granulomatosis (WG) may present as an orbital mass without obvious upper respiratory or systemic features. The authors examined the clinical and pathologic features of a series of cases of orbital WG to define the features of presentation and progression of this disorder. METHODS: Thirteen subjects with orbital presentations of WG were identified from the University of British Columbia Orbit Clinic index of diseases. Clinical features were correlated with the results of computed tomography in 12 cases and orbital biopsy in 11 cases. Antineutrophil cytoplasmic antibody (c-ANCA) testing was performed in five cases. RESULTS: The main ocular symptoms were decreased vision, redness, and ocular and facial pain, whereas the main signs were proptosis, scleritis, and lid inflammation. Progression was marked by an increased incidence of bilaterality and systemic features. Ear, nose, and throat features were discovered at presentation in 11 cases and became universal during the follow-up period. Initial antineutrophil cytoplasmic antibody test results were negative in five patients but became positive later in three patients. Orbital biopsy specimens typically had features of mixed inflammation, fat disruption, and small areas of necrosis. The combination of cyclophosphamide and oral steroids was highly effective in terminating disease episodes. CONCLUSIONS: Orbital WG can be recognized by a constellation of clinical and radiologic findings with evidence of an often erosive, infiltrating, and restrictive fibrotic, inflammatory mass. Concurrent ear, nose, and throat or specific ocular findings such as scleritis with typical limbal infiltrate can occur. Biopsy results show mixed inflammation with evidence of necrosis that must not be regarded as a nonspecific finding.

Monoclonal origin of localised orbital amyloidosis detected by molecular analysis.

AIMS: Primary localised orbital amyloidosis is a rare disease. The purpose of this study was to describe two cases of primary orbital amyloidosis and emphasise the value of molecular analysis of immunoglobulin gene rearrangement in identifying a monoclonal population of cells responsible for the amyloid production. METHODS: Charts and biopsy specimens of each case were reviewed. Conventional light microscopy, immunohistochemistry, and polymerase chain reaction (PCR) analysis for immunoglobulin gene rearrangement were performed in both cases. RESULTS: An unusual presentation of localised primary amyloidosis with bilateral and extensive enlargement of multiple extraocular muscles was seen in case 1. The presence of amyloid deposits was confirmed by biopsy in both cases. Evidence of a monoclonal population of plasma cells was shown by immunohistochemical analysis in case 2 only. The monoclonal origin of the cells responsible for the amyloid deposition was determined by PCR analysis demonstrating immunoglobulin heavy chain gene rearrangement in both cases. CONCLUSIONS: A monoclonal population of plasma cells responsible for the amyloid deposition was present in these two cases. PCR analysis is extremely helpful in determining monoclonality, a finding that may have important therapeutic and prognostic implications.

Occurrence and postmortem generation of anandamide and other long-chain N-acylethanolamines in mammalian brain.

Long-chain N-acylethanolamines (NAEs) were assayed in pig, sheep and cow brain by gas chromatography/mass spectrometry of their tert.-butyldimethylsilyl derivatives in the presence of deuterium-labeled internal standards. Immediately after death, total NAEs ranged from about 2.7 micrograms/g wet weight (sheep, cow) to 6.5 micrograms/g wet weight (pig) and consisted almost exclusively (99%) of saturated and monounsaturated species. Anandamide (20:4n-6 NAE) comprised about 1% of total NAE in pig and cow brain, but was absent in freshly extracted sheep brain. When pig brain was analysed after 0.5, 1, 3, 4 and 23 h at ambient temperature, NAE levels were found to increase substantially over the entire time period with 20:4n-6 NAE formation exhibiting a time lag compared to that of saturated and monounsaturated NAEs.