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PubMedDate not supplied

Measuring cognitive change in a cohort of patients with Alzheimer's disease.

Annualized rates of cognitive change in Alzheimer's disease (AD), an important index of disease progression, show marked variability. To determine factors leading to such variability, we computed rates of change in a cohort of patients with AD tested annually with the Mini Mental State Examination (MMSE) and the more detailed Dementia Rating Scale (DRS). Estimates of rates of change (slopes) and intercepts were calculated using least squares and best linear unbiased predictors (BLUPs). Potential predictors of rates of change were examined using multivariate linear regression analysis. We found that the MMSE had more noise than the DRS. For the MMSE, slopes showed a moderate floor effect and a slight ceiling, depending on initial MMSE scores. These effects were less prominent for the DRS, for which slopes increased as intercepts decreased. In analyses of predictors of change, the MMSE was less useful than the DRS. In multiple linear regression models using DRS data, predictors showed statistically stronger effects and explained a greater extent of variation of slopes than did similar models using MMSE data. For example, among patients who died and underwent brain examination at autopsy, neuropathology of Lewy bodies plus AD (Lewy Body variant; LBV) was associated with significantly faster rates of cognitive decline compared to pure AD in analyses that used the DRS, but only trends were identified with the MMSE. The metric properties and longitudinal characteristics of cognitive tests and the statistical methods used to calculate change are key factors in obtaining reliable estimates of change in studying cohorts of patients with AD.

Aged↗

PubMed2001

Local delivery of paclitaxel using the double-balloon perfusion catheter before stenting in the porcine coronary artery.

Paclitaxel is a new cancer chemotherapeutic agent that has been approved for clinical use in patients with a variety of different cancers. Paclitaxel inhibits cell proliferation by an action on microtubules. The aim of this study was to evaluate the safety and efficacy of locally delivered paclitaxel after coronary stent implantation. A novel double-balloon perfusion catheter was used to deliver the drug locally in the pig coronary artery. Twenty-seven domestic pigs underwent stent implantation of the left anterior descending artery. In the treatment group (n = 11), paclitaxel (10 ml; 10 micromol/l) was delivered using the double-balloon perfusion catheter prior to stent implantation. The control group received stent implantation only (n = 16). The animals were sacrificed 4 weeks later. Vessels were perfusion-fixed and morphometric analysis was performed using conventional techniques. In addition, the extent of injury was determined at each stent-strut area. Correlation of local injury and neointimal thickness was evaluated by linear regression. Neointimal thickness (paclitaxel 1.0 +/- 0.4 vs. control 0.7 +/- 0.3 mm), neointimal area (paclitaxel 4.1 +/- 2.2 vs. control 2.4 +/- 1.1 mm(2)), and the lumen area (paclitaxel 2.1 +/- 1.9 vs. control 2.5 +/- 0.9 mm(2)) did not show significant differences between both groups. Medial area (3.3 +/- 2.3 vs. 1.6 +/- 0.4 mm(2)) was larger in the vessels treated with paclitaxel (P < 0.05). Linear regression failed to show any difference in the response to injury between the two groups. Local delivery of paclitaxel with the double-balloon-perfusion catheter did not reduce neointima formation following stent implantation in native pig coronary arteries.

Angioplasty, Balloon↗

PubMed2002

Measurement of effective air diffusion coefficients for trichloroethene in undisturbed soil cores.

In this study, we measure effective diffusion coefficients for trichloroethene in undisturbed soil samples taken from Picatinny Arsenal, New Jersey. The measured effective diffusion coefficients ranged from 0.0053 to 0.0609 cm2/s over a range of air-filled porosity of 0.23-0.49. The experimental data were compared to several previously published relations that predict diffusion coefficients as a function of air-filled porosity and porosity. A multiple linear regression analysis was developed to determine if a modification of the exponents in Millington's [Science 130 (1959) 100] relation would better fit the experimental data. The literature relations appeared to generally underpredict the effective diffusion coefficient for the soil cores studied in this work. Inclusion of a particle-size distribution parameter, d10, did not significantly improve the fit of the linear regression equation. The effective diffusion coefficient and porosity data were used to recalculate estimates of diffusive flux through the subsurface made in a previous study performed at the field site. It was determined that the method of calculation used in the previous study resulted in an underprediction of diffusive flux from the subsurface. We conclude that although Millington's [Science 130 (1959) 100] relation works well to predict effective diffusion coefficients in homogeneous soils with relatively uniform particle-size distributions, it may be inaccurate for many natural soils with heterogeneous structure and/or non-uniform particle-size distributions.

Air Pollutants↗

PubMed1998

Laryngeal tumor volume measurements determined with CT: a study on intra- and interobserver variability.

PURPOSE: To investigate the intra- and interobserver variability of computed tomography-based volume measurements of laryngeal tumors. METHODS AND MATERIALS: The volume of 13 laryngeal tumors was repeatedly measured by five independent observers in four different sessions, using the summation-of-areas technique. Mean tumor volume and its standard deviation were calculated for each tumor. Statistical analysis was done with analysis of variance, Spearman rank correlation, and linear regression. RESULTS: Both the effect of the observers (p < 0.0001) and the effect of the session (p < 0.01) on tumor volume was statistically significant. Interobserver variability was the most important component of total variability (89.3%). A significant rank correlation was found between mean volume and standard deviation (p < 0.01); the relationship between mean tumor volume and standard deviation can be described using linear regression [standard deviation = 0.28 volume + 0.35 (R = 0.79)]. CONCLUSION: Total variability in the computed tomography-based measurement of laryngeal tumor volume can be reduced by having the measurements done by a single trained observer.

Analysis of Variance↗

PubMed1998

Use of indapamide in hospital and community clinics and its effect on plasma potassium in Chinese patients.

OBJECTIVES: To investigate the usage pattern of indapamide and other antihypertensive drugs in patients attending a community-based government outpatient clinic (GOPC) or a hospital-based specialist clinic (SC). The plasma potassium concentrations of patients receiving indapamide and other diuretics were also examined. METHOD: Prescriptions from the SC and the GOPC were reviewed and collected during January 1998. Patients' plasma potassium concentrations and the date of initiation of each medication were retrieved from the hospital computer databases at SC. An age- and sex-matched control group of patients on non-diuretic antihypertensive drugs was identified. RESULTS: A total of 1648 and 773 prescriptions were collected from the SC during a 1-week period and GOPC during a 1-month period, respectively. Approximately half (45%) of the patients received antihypertensive treatment. Indapamide was five times more frequently prescribed in GOPC than SC (84.7 vs. 17.7%, P<0.001). Calcium channel blocking agents were the commonest antihypertensive drugs used in both clinics. The mean plasma potassium concentration of patients taking indapamide was lower than that of the control group (P = 0.037). Multiple linear regression analysis showed that consumption of indapamide (P =0.002) and duration of diuretic therapy (P = 0.023) were significantly related to changes in plasma potassium concentrations [multiple regression equation for potassium level = 4.09-0.145 (thiazide = 1)-0.377 (indapamide = 1) -0.00468 (duration of diuretic therapy in months)]. CONCLUSION: Indapamide was used extensively in the community clinic and less in the hospital-based outpatient clinic. Patients receiving indapamide had a significantly lower plasma potassium concentration as compared to other diuretics or antihypertensive groups and this was predicted by a multiple linear regression model. Monitoring plasma electrolytes before initiation of indapamide treatment and at regular intervals thereafter is essential for detecting the hypokalaemia that may occur in Chinese patients.

Aged↗

PubMed1996

Specific and total carotenoid intakes among oral contraceptive and estrogen hormone users in the United States.

OBJECTIVE: To compare carotenoid intakes between hormone users and nonusers in a nationally representative sample of US women by demographic and lifestyle characteristics and to identify those with potentially greater risk for disease. DESIGN: Data from the 1987 National Health Interview Survey's-Epidemiology Supplement food frequency questionnaire were linked to the USDA-NCI Carotenoid database to estimate mean total and specific carotenoid intakes. SUBJECTS: Women (n = 8,962) were grouped by menopausal status and classified by hormone use into premenopausal oral contraceptive users/nonusers (n = 5,918) and postmenopausal estrogen replacement hormone users/nonusers (n = 3,044). STATISTICAL ANALYSES PERFORMED: Mean carotenoid intakes and standard errors were weighted using SUDAAN and adjusted for potential confounding factors using multiple linear regression analysis. Statistically significant differences were at p values < 0.01. RESULTS: Compared to nonusers, oral contraceptive users had lower specific carotenoid intakes. Demographic and lifestyle characteristics differed between oral contraceptive users/nonusers and were examined in relation to carotenoid intakes. More oral contraceptive users than nonusers were married, highly educated, drank alcoholic beverages, and smoked. After adjustment for these factors in a multiple linear regression model, the associations between oral contraceptive use and carotenoid intake remained statistically significant. Mean carotenoid intakes were not significantly different among estrogen hormone replacement users versus nonusers. CONCLUSIONS: Oral contraceptive users have lower dietary carotenoid intakes than nonusers. Since oral contraceptive users smoke and drink more than nonusers, and both factors are associated with lower carotenoid intakes, oral contraceptive users form a potential high risk group for disease.

Alcohol Drinking↗

PubMed1985

Evaluation of an index of peripheral vascular resistance in human subjects.

Based on evidence in animal studies, an index of resistance in man has been evaluated. In 10 human subjects, ranging in age from 31 to 60 years, direct brachial arterial pressure was measured, and a computer program using linear regression calculated the index of resistance from the slope of the logarithm of the pressure versus time during the second half of diastole. Resistance was independently calculated from 20-s averages of pressure and cardiac output obtained by thermodilution. Resistance was varied by infusion of phenylephrine and nitroprusside. The values of the index of resistance were compared with independently calculated resistance by linear regression and correlation. The index of resistance was variably correlated with independently calculated resistance. However, when the comparison was limited to points with a model correlation coefficient greater than or equal to 0.98 (i.e. a good fit of a straight line to the logarithm of pressure versus time), the correlation of the index of resistance with calculated resistance approached or exceeded 0.9 in eight of 10 subjects. In the two subjects showing poor correlation of the index with calculated resistance, estimated compliance from the same model was much lower than in the other subjects. In the same two subjects pressure dependence of estimated compliance was much higher than in the other subjects, suggesting the presence of significant atherosclerosis. We concluded that the diastolic decay of pressure may be used to calculate a useful index of resistance, provided that a single exponential decay fits the observed diastolic waveform well, and arterial compliance is not significantly reduced by atherosclerosis.

Adult↗

PubMedDate not supplied

Evaluation of heart time-activity curves as a predictor of hepatic extraction of 99mTc-mebrofenin in dogs.

In this study, heart time-activity curve, created following intravenous injection of 99mTc-mebrofenin were used to quantify hepatic function in normal dogs and dogs with induced hepatic parenchymal cell damage. The results were compared to a direct measurement of hepatic extraction following mesenteric venous injection of 99mTc-mebrofenin. The heart time-activity curves were normalized and the area under the curve from 0-30 minutes and 0-60 minutes were determined. In addition, the half-time clearance rate of the heart time-activity curve was analyzed using a two-compartment model. Linear regression analysis was used to describe the relationship between the area under the normalized heart time-activity curve and hepatic extraction. There was good correlation between the area under the normalized heart time-activity curve and hepatic extraction. The best correlation was obtained from the 0-30 minute data (r2 = 0.92). A formula for calculating hepatic extraction was derived using linear regression analysis: Hepatic extraction = 1.092 - (0.0000308 x AUC0-30 minutes). There was good correlation between the half-time clearance rates from the heart time-activity curve and hepatic extraction. The best correlation was between the fast phase half-time clearance and hepatic extraction (r2 = 0.88). The area under a normalized heart time-activity curve can be used as a simple alternative to deconvolutional analysis for the determination of hepatic extraction as a measure of hepatic parenchymal cell function in the dog.

Aniline Compounds↗

PubMed1990

Left ventricular volume determination in the horse by two-dimensional echocardiography: an in vitro study.

This study was designed to evaluate the accuracy of two-dimensional echocardiography (2DE) in determining the left ventricular volume (LVV) of the horse in vitro. After examining the shape of the left ventricular silicon rubber casts of four equine hearts, two modified Simpson's rule methods (Model A and Model B) as combinations of conical shapes and one biplane area-length method as a single cone (Model C) were chosen for volume calculations. One long axis and three short axis planes were used for linear and area 2DE measurements, respectively. The ventricular length (L) was calculated from the chordal length (CL) by using a linear regression equation (L = 5.54 + 1.83 CL) obtained by anatomical measurement of these two parameters on 40 normal hearts. The LVV was calculated in 15 formalin-fixed hearts from 2DE measurements with the three geometric models. Left ventricular casts were then made using silicon rubber, and their volumes were determined by water displacement. The calculated volumes were plotted against cast volumes with linear regression analysis. All calculated LVVs correlated well with the cast LVVs (R = 0.921 to 0.957; P less than 0.001). The highest correlation was provided by Model A which best represented the shape of the left ventricle. This model consisted of a truncated cone bordered by the area at the level of the mitral valve and by the area at the level of the chordae tendineae, plus a cone the base of which was the area at the level of the papillary muscles. The results demonstrate the applicability of 2DE for equine LVV determinations in vitro, similar to other species.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2003

Analysis of body segment parameter differences between four human populations and the estimation errors of four popular mathematical models.

Calculating the kinetics of motion using inverse or forward dynamics methods requires the use of accurate body segment inertial parameters. The methods available for calculating these body segment parameters (BSPs) have several limitations and a main concern is the applicability of predictive equations to several different populations. This study examined the differences in BSPs between 4 human populations using dual energy x-ray absorptiometry (DEXA), developed linear regression equations to predict mass, center of mass location (CM) and radius of gyration (K) in the frontal plane on 5 body segments and examined the errors produced by using several BSP sources in the literature. Significant population differences were seen in all segments for all populations and all BSPs except hand mass, indicating that population specific BSP predictors are needed. The linear regression equations developed performed best overall when compared to the other sources, yet no one set of predictors performed best for all segments, populations or BSPs. Large errors were seen with all models which were attributed to large individual differences within groups. Equations which account for these differences, including measurements of limb circumferences and breadths may provide better estimations. Geometric models use these parameters, however the models examined in this study did not perform well, possibly due to the assumption of constant density or the use of an overly simple shape. Creating solids which account for density changes or which mimic the mass distribution characteristics of the segment may solve this problem. Otherwise, regression equations specific for populations according to age, gender, race, and morphology may be required to provide accurate estimations of BSPs for use in kinetic equations of motion.

Absorptiometry, Photon↗

PubMed2003

Procollagen II C propeptide level in the synovial fluid as a predictor of radiographic progression in early knee osteoarthritis.

OBJECTIVE: To investigate the prognostic value of procollagen type II carboxy-terminal propeptide (PIICP) level in synovial fluid in relation to early tibiofemoral joint osteoarthritis (OA). METHODS: Data were collected on 172 women (age 40 to 59 years) who had knee pain and tibiofemoral joint OA in the early stage. Standing semiflexed knee radiographs were obtained by fluoroscopy at baseline and at four year follow up and a computerised, magnification corrected measurement system was applied to measurement of minimal joint space width in the tibiofemoral compartment. Synovial fluid sampling was performed at baseline and at the four year follow up. Levels of PIICP in the synovial fluid were measured by enzyme immunoassay. The outcome measures were assessed by radiographic joint space narrowing (JSN) in the tibiofemoral joints over four years. Multiple linear regression analyses were used to examine the relation between radiographic JSN and synovial fluid level of PIICP. RESULTS: The number of women available at both baseline and at four year follow up was 110. The average of radiographic JSN over four years was 0.53 mm (range 0.00-2.01). Body mass index showed a slightly positive association with baseline PIICP level. In multiple linear regression analyses adjusted for age and body mass index, radiographic JSN over four years had a direct positive correlation with baseline PIICP level (r=0.395; 95% confidence interval (95% CI) 0.231 to 0.529; p<0.001). CONCLUSION: In a four year prospective study of women, quantification of synovial fluid PIICP was able to predict subsequent radiographic progression in early tibiofemoral joint OA.

Adult↗

PubMed1996

Changes in cerebral tissue perfusion during the first 48 hours of ischaemic stroke: relation to clinical outcome.

BACKGROUND: One major therapeutic strategy to minimise the extent of infarction after ischaemic stroke is to improve early reperfusion using thrombolytic agents. However, reperfusion may be hazardous and the period during which reperfusion may have a beneficial effect on tissue and clinical outcome is not known. METHODS: Fifty three patients were studied with serial cerebral perfusion (99mTcHMPAO SPECT) during the first 48 hours of ischaemic stroke to determine if changes in tissue perfusion during this time were prognostically significant. Single and multiple linear regression non-parametric analyses were used to include other factors during the same period which may influence outcome. RESULTS: In univariate analysis age, neurological score at admission, SPECT perfusion defect size in the first 24 hours, and percentage change in cerebral tissue perfusion at 24-48 hours (all P < 0.01) correlated significantly with the Barthel score at three months. In multiple linear regression analysis only age (P < 0.01) and percentage change in cerebral tissue perfusion at 24-48 hours (P < 0.01) provided independent prognostic information at three months. CONCLUSIONS: Changes in cerebral tissue perfusion during the first 48 hours of ischaemic stroke are significant outcome predictors and therapeutic effort aimed at increasing perfusion during this period seem to be justified.

Aged↗

PubMed1981

The relationship of hair zinc concentrations to height, weight, age, and sex in the normal population.

Hair samples from forty-nine normal individuals (both children and adults) were assessed for concentrations of zinc. Pearson correlation coefficients were computed between zinc values and the variables: height, weight, and age (see Table 3). In children (under 240 months), all these relationships were linear, positive, and statistically significant. A linear regression equation using all these variables was found to account for 47.7% of the variance in hair zinc concentrations. In adults (over 240 months), the correlation coefficients between hair zinc and height, weight, and age were not found to be significant, with the exception of the negative correlation between hair zinc and weight (r = -0.464; P less than 0.047). Nevertheless, a multivariate linear regression equation accounted for about 24.6% of the variability of hair zinc values. In both children and adults, tests for sex differences in means and standard deviations using both raw score and residual values failed to reveal any significant differences. Similarly, no significant sex differences were observed between corresponding correlation coefficients. Results indicate that future studies utilizing hair must systematically or mathematically control for individual variation in zinc concentrations due to differences in age, weight, and height.

Adolescent↗

PubMed1975

Angiographic determination of left ventricular muscle mass in the dog.

Left ventricular (LV) cineangiography in the right anterior oblique projection was carried out in 7 dogs. Calculation of LV muscle mass (LMM) was based on the determination of end-diastolic volume (EDV) and posterior wall thickness (h). Three different procedures of calculation were used. (A) EDV was determined according to the technique of Greene [8]; h was assumed to be equal around the LV cavity. (B) Systematic overestimation of EDV by Greene's method was corrected according to the regression equation proposed by Bentivoglio [9]; h was the same as in A. (C) EDV was corrected as in B; h at the ends of the long axis was assumed to be only half of that at the minor axis (i.e. h/2). The calculated values of LMM (4 to 11) in the individual dogs were averaged and compared with the true LMM determined at autopsy. True LMM in 7 dogs was 96 +/- 6 g (SE). Method A yielded 122 +/- 9 g (P less than 0.01) and method C 91 +/- 6 G (P greater than 0.05). Linear regression analysis between calculated and weighed LMM yielded a correlation coefficient of 0.936 in A, 0.938 in B and 0.931 in C. The SEE was 8.8 g, 7.5 g and 6.6 g, respectively. It is concluded that LMM can be determined with reasonable accuracy from linear regression equations whereby method C appears to be the preferable mode of calculation (smallest SEE).

Angiocardiography↗

PubMed2004

The impact of non-injury-related factors on disability secondary to whiplash associated disorder type II: a retrospective file review.

BACKGROUND: There is evidence to suggest that Whiplash Associated Disorders (WADs) are influenced by physical trauma and psychosocial factors, as well as by medicolegal and compensation systems. OBJECTIVE: To investigate the impact of noninjury related variables on self-reported disability at initial assessment among patients presenting with WAD type II injuries. DESIGN AND SETTING: We reviewed a total of 1101 consecutive files of patients presenting to a single chiropractor's office in British Columbia, Canada. We included those who met the inclusion criteria. We extracted demographic variables and noninjury related information from 33 eligible patient files. We calculated correlations between variables and created a multivariable linear regression model to evaluate their relative associations with Neck Disability Index (NDI) scores on presentation. RESULTS: Higher NDI scores on initial assessment correlated with female sex (r = 0.40, P =.02), a greater number of subsequent treatments (r = 0.44, P =.01), a higher number of providers seen before presentation (r = 0.40, P =.02), and most strongly with the involvement of a lawyer (r = 0.73, P <.01). A multivariable linear regression model found that only female sex (P =.03) and the involvement of a lawyer (P =.01) remained significantly associated with higher NDI scores on presentation (adjusted R2 = 0.68 for the model). Female sex was associated with a 10-point increase in NDI scores on presentation (beta coefficient = 10.5; 95% confidence interval [CI] 2.8-18.2), and involvement of a lawyer was associated with a 15-point increase in NDI scores on presentation (beta coefficient = 14.9; 95% CI 5.0-24.7). CONCLUSION: Our analysis of WAD type II patients in receipt of compensation found that higher self-reported disability on initial assessment was associated with female sex and in particular by retaining a lawyer. Large prospective studies are needed to establish the validity of these findings.

Adult↗

PubMedDate not supplied

The reliability of central corneal thickness measurements by ultrasound and by Orbscan system in schoolchildren.

PURPOSE: To compare the central corneal thickness measurements obtained by ultrasound (US) pachymetry and the Orbscan II system in healthy schoolchildren. METHODS: A total of 356 schoolchildren aged 7 to 12 years underwent central cornal thickness (CCT) measurement with Orbscan II and ultrasonic pachymetry. All eyes were examined first with the Orbscan II and then by US pachymetry. The mean of the difference, standard deviation (SD), and 95% limits of agreement, with and without applying the acoustic correction factor, were determined. The differences between the devices in measuring mean CCT were calculated with paired-sample t test. Pearson correlation test was used to determine the correlation between variables. p < 0.05 was considered to be statistically significant. Linear regression analysis was used to quantify the correlation between the two methods. RESULTS: Orbscan II measurements were significantly higher than US pachymetry measurements without applying the manufacturer-recommended acoustic correction factor (0.92) correction (580.39 +/- 37 microm and 562.95 +/- 32 microm, respectively) (p < 0.0001). When this acoustic correction factor was applied, the Orbscan II measurements demonstrated significantly lower results when compared with those of US pachymetry (533.96 +/- 34 microm and 562.95 +/- 32 microm, respectively) (p < 0.0001). The linear regression analysis lines showed approximately 45-degree slope indicating a strong correlation between these methods (US pachymetry = 145.71 + 0.72 x Orbscan II value without acoustic correction factor (microm), r = 0.89, p < 0.0001). There was a high degree of variability in differences between the 2 devices in individual subjects. The range was between 25 to -55 microm without the acoustic correction factor and 67 to -5 microm with the acoustic correction factor. CONCLUSIONS: Although US pachymetry and Orbscan II demonstrated a strong linear correlation, there was a high degree of variability in differences between the two devices in individual subjects who participated.

Body Weights and Measures↗

PubMed1999

Relationship between exercise capacity and ventilatory equivalent for carbon dioxide in patients with stable old myocardial infarction.

The aim of the present study was to evaluate the relationship between exercise capacity and ventilatory response in patients with stable old myocardial infarction. We performed cardiopulmonary exercise test in 61 patients with stable old myocardial infarction and in 30 healthy men. Each subject exercised on a bicycle ergometer until exhaustion. Patients who had anginal pain or electrocardiographic ischemic changes during exercise were excluded. The patients were classified into three groups according to peakVO2 achieved during exercise, using Weber's method: group A, peakVO2 > or = 21 ml/min/kg (n = 4); group B, 14 < or = peakVO2 < 21 ml/min/kg (n = 45); and group C, peakVO2 < 14 ml/min/kg (n = 12). With progressive increases in VCO2, VE increased linearly below the anaerobic threshold (AT) level. The slope of the linear regression line between VCO2 and VE (SLOPE) was calculated in each subject. The mean SLOPE of the healthy men (group N) and groups A, B and C were 25.8 +/- 0.5, 25.1 +/- 0.5, 28.9 +/- 0.8 and 37.1 +/- 1.7 (x 10(-3), respectively. Thus, the SLOPE was steeper in patients with lower peakVO2. It is difficult to perform a maximal exercise tolerance test on patients with chronic heart failure to evaluate their exercise capacity. We can assess exercise capacity by the slope of the linear regression line between VCO2 and VE (SLOPE) at the lower exercise level.

Aged↗

PubMed1998

Functional indices for sciatic, peroneal, and posterior tibial nerve lesions in the mouse.

The sciatic functional index previously described in rats has proven to be a reliable index of functional recovery following sciatic nerve injury and repair. A similar functional assay of sciatic, peroneal, and posterior tibial nerve lesions was developed in a mouse model. Forty-eight C57/BL6 mice were randomly divided into 4 groups: sham surgery, sciatic nerve transection, peroneal nerve transection, and posterior tibial nerve transection. Preoperative and postoperative (48 hours) walking tracks were obtained. The pawprints were analyzed in a blinded fashion for measurements of print length (PL), toe spread (TS), intermediate toe spread (IT), and the orthogonal distance from the toe of one paw to the hind pad of the opposite paw (TOF). Multiple linear regression analysis was performed using these measurements to determine their significance and appropriate weighted contribution to the index formula for each nerve lesion. For the sciatic functional index, changes in the PL (P = 0.0092) and TS (P = 0.0008) were significant, resulting in an R2 value of 0.88. For the peroneal functional index, only TS (P < 0.0001) was significant with R2 = 0.83. For the posterior tibial index, only PL (P < 0.0001) was significant with R2 = 0.89. Formulas for a sciatic, peroneal, and posterior tibial functional index were created based on the coefficients derived from the multiple linear regression analysis. The indices that were developed will allow investigators to assess functional recovery following specific nerve lesions in mice.

Animals↗