MUlti-Dimensional Spline-Based Estimator (MUSE) for Motion Estimation: Algorithm Development and Initial Results

Image registration and motion estimation play central roles in many fields, including RADAR, SONAR, light microscopy, and medical imaging. Because of its central significance, estimator accuracy, precision, and computational cost are of critical importance. We have previously presented a highly accurate, spline-based time delay estimator that directly determines sub-sample time delay estimates from sampled data. The algorithm uses cubic splines to produce a continuous representation of a reference signal and then computes an analytical matching function between this reference and a delayed signal. The location of the minima of this function yields estimates of the time delay. In this paper we describe the MUlti-dimensional Spline-based Estimator (MUSE) that allows accurate and precise estimation of multi-dimensional displacements/strain components from multi-dimensional data sets. We describe the mathematical formulation for two- and three-dimensional motion/strain estimation and present simulation results to assess the intrinsic bias and standard deviation of this algorithm and compare it to currently available multi-dimensional estimators. In 1000 noise-free simulations of ultrasound data we found that 2D MUSE exhibits maximum bias of 2.6 × 10⁻⁴ samples in range and 2.2 × 10⁻³ samples in azimuth (corresponding to 4.8 and 297 nm, respectively). The maximum simulated standard deviation of estimates in both dimensions was comparable at roughly 2.8 × 10⁻³ samples (corresponding to 54 nm axially and 378 nm laterally). These results are between two and three orders of magnitude better than currently used 2D tracking methods. Simulation of performance in 3D yielded similar results to those observed in 2D. We also present experimental results obtained using 2D MUSE on data acquired by an Ultrasonix Sonix RP imaging system with an L14-5/38 linear array transducer operating at 6.6 MHz. While our validation of the algorithm was performed using ultrasound data, MUSE is broadly applicable across imaging applications.     

Correspondence of Visual Evoked Potentials with FMRI Signals in Human Visual Cortex

Functional magnetic resonance imaging (FMRI) and event related potentials (ERPs) are tools that can be used to image brain activity with relatively good spatial and temporal resolution, respectively. Utilizing both of these methods is therefore desirable in neuroimaging studies to explore the spatio-temporal characteristics of brain function. While several studies have investigated the relationship between EEG and positive (+) BOLD (activation), little is known about the relationship between EEG signals and negative (−) BOLD (deactivation) responses. In this study, we used a visual stimuli designed to shift cortical activity from anterior to posterior regions of the visual cortex. Using EEG and FMRI, we investigated how shifts in +BOLD and −BOLD location were correlated to shifts in the N75 and P100 visual evoked potential (VEP) dipolar sources. The results show that the N75 dipole along with +BOLD, were indeed shifted from posterior to anterior regions of the visual cortex. The P100 VEP component, along with the −BOLD were not shifted to the same extent, indicating that N75 is better correlated to +BOLD than to −BOLD. These findings indicate how different components of the EEG signal are related to the positive and negative BOLD responses, which may aid in interpreting the relationship between visually evoked EEG and FMRI signals. An erratum to this article can be found at     

Effect of a single and repeated dose of caffeine on antigen-stimulated human natural killer cell CD69 expression after high-intensity intermittent exercise

Several studies investigating the effect of caffeine on immune function following exercise have used one large bolus dose of caffeine. However, this does not model typical caffeine consumption. Therefore, the purpose of this study was to investigate whether small repeated doses of caffeine ingested throughout the day would elicit a similar response as one large bolus dose ingested 1 h prior to exercise on antigen-stimulated NK cell CD69 expression following strenuous intermittent exercise. In a randomized cross-over design, 15 healthy males completed six 15 min blocks of intermittent running consisting of maximal sprinting interspersed with less intense running and walking. Participants had ingested either 0 (PLA), 2 mg kg⁻¹ body mass (BM) caffeine on three separate occasions during the day (3× CAF) or one dose of 6 (1× CAF) mg kg⁻¹ BM caffeine, 1 h before exercise. At 1-h post-exercise, the number of antigen-stimulated CD3⁻CD56⁺ cells expressing CD69 was lower on 1× CAF compared with PLA [P < 0.05; PLA: 42.0 (34.0) × 10⁶ cells L⁻¹, 1× CAF: 26.2 (25.0) × 10⁶ cells L⁻¹], with values on 1× CAF at this time point remaining close to pre-supplement. 1× CAF tended to attenuate the exercise-induced increase in geometric mean fluorescence intensity of CD69 expression on antigen-stimulated CD3⁻CD56⁺ cells 1-h post-exercise [P = 0.055; PLA: 141 (28)%, 1× CAF: 119 (20)%]. These findings suggest that although one large bolus dose of caffeine attenuated the exercise-induced increase in antigen-stimulated NK cell CD69 expression 1 h following strenuous intermittent exercise, this attenuation at no point fell below pre-supplement values and caffeine does not appear to depress NK cell CD69 expression.     

Examining the accumulated oxygen deficit method in breaststroke swimming

The present study investigated the accumulated oxygen deficit (AOD) method in breaststroke swimming with the aims to assess the reliability of the oxygen uptake/swimming velocity regression line and to quantify the precision of the AOD. Sixteen male swimmers performed two swimming tests in different days, with a 24-h recovery between tests: a graded swimming test and an all-out test. The all-out test was performed in one of two distances: 100 m (n = 7) or 200 m (n = 9). Through all testing, expired gases were collected breath by breath and analysed with a K4b2 Gas Analyser (Cosmed, Rome, Italy) connected to an AquaTrainer Valve (Cosmed, Rome, Italy). The standard error of the regression lines was ≈5–6 ml kg⁻¹ min⁻¹ and the regressions allowed an extrapolation of the energy cost to higher intensities with a standard error of the predicted value that was lower in the 200-m bout (≈3.5 ml kg⁻¹ min⁻¹) comparatively to the 100-m bout (≈6 ml kg⁻¹ min⁻¹). The AOD imprecision was calculated as the square root of the sum of the oxygen uptake measurement error and the standard error of the predicted value for energy cost. AOD imprecision was smaller in the 200-m bout (≈9 ml kg⁻¹ min⁻¹) comparatively to the 100-m bout (≈12 ml kg⁻¹ min⁻¹). However, since the AOD values during the two distances were small, the AOD relative errors can be viewed as high. Additionally, the data variability was considerable (95% confidence intervals of the linear extrapolation larger than 20 ml kg⁻¹ min⁻¹).     

Effect of Lysophosphatidylcholine on α-Adrenoreactivity of Rat Aorta Smooth Muscles

In experiments on rat aortic ring segments, lysophosphatidylcholine in concentrations of 2 × 10⁻⁶, 2 × 10⁻⁵, and 2 × 10⁻⁴ M did not suppress the tonotropic effect of phenylephrine (6 × 10⁻⁶ and 6 × 10⁻⁵ M) and in concentration of 2 × 10⁻⁵ M even potentiated it, which was noted for phenylephrine at a concentration of 6 × 10⁻⁶ M. It was concluded that the chemomodulating effect of lysophosphatidylcholine depends on the type of receptors and cells.     

Measuring orientation of human body segments using miniature gyroscopes and accelerometers

In the medical field, there is a need for small ambulatory sensor systems for measuring the kinematics of body segments. Current methods for ambulatory measurement of body orientation have limited accuracy when the body moves. The aim of the paper was to develop and validate a method for accurate measurement of the orientation of human body segments using an inertial measurement unit (IMU). An IMU containing three single-axis accelerometers and three single-axis micromachined gyroscopes was assembled in a rectangular box, sized 20×20×30 mm. The presented orientation estimation algorithm continuously corrected orientation estimates obtained by mathematical integration of the 3D angular velocity measured using the gyroscopes. The correction was performed using an inclination estimate continuously obtained using the signal of the 3D accelerometer. This reduces the integration drift that originates from errors in the angular velocity signal. In addition, the gyroscope offset was continuously recalibrated. The method was realised using a Kalman filter that took into account the spectra of the signals involved as well as a fluctuating gyroscope offset. The method was tested for movements of the pelvis, trunk and forearm. Although the problem of integration drift around the global vertical continuously increased in the order of 0.5°s ⁻¹, the inclination estimate was accurate within 3° RMS. It was shown that the gyroscope offset could be estimated continuously during a trial. Using an initial offset error of 1 rads ⁻¹, after 2 min the offset error was roughly 5% of the original offset error. Using the Kalman filter described, an accurate and robust system for ambulatory motion recording can be realised.     

Prototype for real-time adaptive sampling using the fan algorithm

Retrospective studies have established that the fan algorithm is an effective means of acquiring high-quality digital cardiac measurements. A prototype has now been constructed that samples adaptively in real time. The prototype uses two Texas Instruments TMS32010 signal processors and 79 additional TTL integrated circuits, at a component cost of approximately US$1000. The device acquires transient samples of the incoming analogue signal at up to 16000 samples s⁻¹, selects samples from this input stream according to the fan algorithm, and transmits the samples and the time intervals between them at a fixed permanent rate. The permanent rate is between 100 and 400 samples s⁻¹, as selected by the user. To respond to changing waveforms and repetition rates, while maintaining a fixed transmission rate, the prototype varies the fan tolerance. The lowest fan tolerance that will allow transmission of samples and time intervals at a rate not exceeding the permanent rate is used. If permanent samples at uniform intervals result in lower peak error than the fan samples, the prototype transmits the uniformly spaced samples instead of the fan samples. Results with test and real signals show that the device performs as designed and can accurately measure fast waveforms at low average sampling rates. For example, bipolar pulses 350 μs in duration were recorded with permanent rates of only 400 samples s⁻¹, and cardiac signals were measured with 10–390 times lower peak error than would have resulted from uniform sampling at the same average rates.     

Acoustic transmission of the aortic component of the second heart sound within the ascending aorta of dogs

The spectral characteristics of the acoustic transmission of the aortic component of the second heart sound within the ascending aorta was studied using a Millar dual-micromanometer catheter. The tip micromanometer was located close to the aortic valve leaflets while the second micromanometer was located 3 cm above the aortic valve. The frequency response of the transmission properties (amplitude and phase) of the blood and the aortic wall was modelled by an equivalent acoustic transmission system. The signal recorded by the tip micromanometer located near the aortic valve was considered to be the input signal of the equivalent system and the signal recorded by the second micromanometer was used as the output signal. Results of the spectral analysis of the input and output signals show that the acoustic transmissibility of blood in the ascending aorta is high at 20 Hz (the attenuation is negligible). Between 20 and 60Hz, the transmissibility decreases at a rate of −3dB per octave while between 60 and 120 Hz it decreases at a rate of −14dB per octave. Above 120Hz the transmissibility is low and the resulting attenuation is greater than 20 dB. The phase of the transfer function is shifted by −60°g at 20Hz and decreases at a mean rate of −2·0°Hz⁻¹ between 20 and 100Hz and −0·75°Hz⁻¹ up to 400Hz. The phase velocity of the sound transmission is relatively constant (5·5ms⁻¹) between 40 and 100Hz and increases up to 9ms⁻¹ at 300Hz.     

Carbohydrate intake reduces fat oxidation during exercise in obese boys

The recent surge in childhood obesity has renewed interest in studying exercise as a therapeutic means of metabolizing fat. However, carbohydrate (CHO) intake attenuates whole body fat oxidation during exercise in healthy children and may suppress fat metabolism in obese youth. To determine the impact of CHO intake on substrate utilization during submaximal exercise in obese boys, seven obese boys (mean age: 11.4 ± 1.0 year; % body fat: 35.8 ± 3.9%) performed 60 min of exercise at an intensity that approximated maximal fat oxidation. A CHO drink (CARB) or a placebo drink (CONT) was consumed in a double-blinded, counterbalanced manner. Rates of total fat, total CHO, and exogenous CHO (CHO_exo) oxidation were calculated for the last 20 min of exercise. During CONT, fat oxidation rate was 3.9 ± 2.4 mg × kg fat-free mass (FFM)⁻¹ × min⁻¹, representing 43.1 ± 22.9% of total energy expenditure (EE). During CARB, fat oxidation was lowered (p = 0.02) to 1.7 ± 0.6 mg × kg FFM⁻¹ × min⁻¹, contributing to 19.8 ± 4.9% EE. Total CHO oxidation rate was 17.2 ± 3.1 mg × kg FFM⁻¹ × min⁻¹ and 13.2 ± 6.1 mg × kg FFM⁻¹ × min⁻¹ during CARB and CONT, respectively (p = 0.06). In CARB, CHO_exo oxidation contributed to 23.3 ± 4.2% of total EE. CHO intake markedly suppresses fat oxidation during exercise in obese boys.     

Effect of exercise on glutamine metabolism in macrophages of trained rats

This study investigated the effect of exercise on glutamine metabolism in macrophages of trained rats. Rats were divided into three groups: sedentary (SED); moderately trained (MOD) rats that were swim trained 1 h/day, 5 days/week for 6 weeks; and exhaustively trained (EXT) rats that were similarly trained as MOD for 5 weeks and, in the 6th week, trained in three 1-h sessions/day with 150 min of rest between sessions. The animals swam with a load equivalent to 5.5% of their body weight and were killed 1 h after the last exercise session. Cells were collected, and glutamine metabolism in macrophage and function were assayed. Exercise increased phagocytosis in MOD when compared to SED (34.48 ± 1.79 vs 15.21 ± 2.91%, P < 0.05); however, H₂O₂ production was higher in MOD (75.40 ± 3.48 nmol h × 10⁵ cell⁻¹) and EXT (79.20 ± 1.18 nmol h × 10⁵ cell⁻¹) in relation to SED (32.60 ± 2.51 nmol h × 10⁵ cell⁻¹, P < 0.05). Glutamine consumption increased in MOD and EXT (26.53 ± 3.62 and 19.82 ± 2.62 nmol h × 10⁵ cell⁻¹, respectively) relative to SED (6.72 ± 0.57 nmol h × 10⁵ cell⁻¹, P < 0.05). Aspartate increased in EXT (9.72 ± 1.14 nmol h × 10⁵ cell⁻¹) as compared to SED (1.10 ± 0.19 nmol h × 10⁵ cell⁻¹, P < 0.05). Glutamine decarboxylation was increased in MOD (12.10 ± 0.27 nmol h × 10⁵ cell⁻¹) and EXT (16.40 ± 2.17 nmol h × 10⁵ cell⁻¹) relative to SED (1.10 ± 0.06 nmol h × 10⁵ cell⁻¹, P < 0.05). This study suggests an increase in macrophage function post-exercise, which was supported by enhanced glutamine consumption and metabolism, and highlights the importance for glutamine after exercise.     

Comparative NMR studies of diffusional water permeability of red blood cells from different species. X. Camel ( Camelus dromedarius ) and alpaca ( Lama pacos )

The diffusional water permeability (P _d) of camel and alpaca red blood cells (RBCs) was measured by a doping nuclear magnetic resonance (NMR) technique on control cells and following inhibition withp-chloromercuribenzene sulphonate (PCMBS). The values ofP _d were, in the case of alpaca RBC≈4.6×10⁻³ cm/s at 25°C, 5.4×10⁻³ cm/s at 30°C, 6.6×10⁻³ cm/s at 37°C and 7.7×10⁻³ cm/s at 42°C. In case of camel RBC the values ofP _d where ≈4.2×10⁻³ cm/s and 9.0×10⁻³ cm/s at 42°C. Systematic studies on the effects of PCMBS on water diffusion in camel RBC indicated that the maximal inhibition was reached in 45 min with 1–2 mm PCMBS. The values of maximal inhibition were around 47% at 25°C and 68% at 30°C for alpaca RBC and around 62% at 25°C and 56% at 37°C for camel RBC. The basal permeability to water of alpaca RBC was estimated at around 2.6×10⁻³ cm/s at 25°C, 1.7×10⁻³ cm/s at 30°C and of camel RBC as 1.8×10⁻³ cm/s at 25°C and 3.0×10⁻³ cm/s at 37°C. The values of the activation energy of water diffusion (E _{a, d}) were around 23 kJ/mol for camel and 34 kJ/mol for alpaca RBC. This suggests that in addition to the number of transport channels other features of the pathways might be important for defining the temperature dependence of the water permeability.     

Hemoglobin Glycation Rate Constant in Non-diabetic Individuals

The objectives were as follows: (1) estimating mean value of the overall hemoglobin glycation rate constant (k); (2) analyzing inter-individual variability of k; (3) verifying ability of the hemoglobin A1c (HbA1c) formation model to predict changes of HbA1c during red blood cells cultivation in vitro and to reproduce the clinical data. The mean k estimated in a group of 10 non-diabetic subjects was equal to 1.257 ± 0.114 × 10⁻⁹ L mmol⁻¹ s⁻¹. The mean k was not affected by a way of estimation of glycemia. The mean k differed less than 20% from values reported earlier and it was almost identical to the mean values calculated on basis of the selected published data. Analysis of variability of k suggests that inter-individual heterogeneity of HbA1c formation is limited or rare. The HbA1c mathematical model was able to predict changes of HbA1c in vitro resulting from different glucose levels and to reproduce a linear relationship of HbA1c and average glucose obtained in the A1C-Derived Average Glucose Study. This study demonstrates that the glycation model with the same k value might be used in majority of individuals as a tool supporting interpretation of HbA1c in different clinical situations.     

Modeling Respiratory Movement Signals During Central and Obstructive Sleep Apnea Events Using Electrocardiogram

Obstructive sleep apnea (OSA) causes a pause in airflow with continuing breathing effort. In contrast, central sleep apnea (CSA) event is not accompanied with breathing effort. CSA is recognized when respiratory effort falls below 15% of pre-event peak-to-peak amplitude of the respiratory effort. The aim of this study is to investigate whether a combination of respiratory sinus arrhythmia (RSA), ECG-derived respiration (EDR) from R-wave amplitudes and wavelet-based features of ECG signals during OSA and CSA can act as surrogate of changes in thoracic movement signal measured by respiratory inductance plethysmography (RIP). Therefore, RIP and ECG signals during 250 pre-scored OSA and 150 pre-scored CSA events, and 10 s preceding the events were collected from 17 patients. RSA, EDR, and wavelet decomposition of ECG signals at level 9 (0.15–0.32 Hz) were used as input to the support vector regression (SVR) model to recognize the RIP signals and classify OSA from CSA. Using cross-validation test, an optimal SVR (radial basis function kernel; C = 2⁸ and ε = 2⁻² where C is the coefficient for trade-off between empirical and structural risk and ε is the width of ε-insensitive region) showed that it correctly recognized 243/250 OSA and 139/150 CSA events (95.5% detection accuracy). Independent test was performed on 80 OSA and 80 CSA events from 12 patients. The independent test accuracies of OSA and CSA detections were found to be 92.5 and 95.0%, respectively. Results suggest superior performance of SVR using ECG as the surrogate in recognizing the reduction of respiratory movement during OSA and CSA. Results also indicate that ECG-based SVR model could act as a potential surrogate signal of respiratory movement during sleep-disordered breathing.     

Finite element modeling of drug distribution in the vitreous humor of the rabbit eye

Direct intravitreal injection of drug is a common method for treating diseases of the retina or vitreous. The stagnant nature of the vitreous humor and surrounding tissue barriers creates concentration gradients within the vitreous that must be accounted for when developing drug therapy. The objective of this research was to study drug distribution in the vitreous humor of the rabbit eye after an intravitreal injection, using a finite element model. Fluorescein and fluorescein glucuronide were selected as model compounds due to available experimental data. All required model parameters were known except for the permeability of these compounds through the retina, which was determined by fitting model predictions to experimental data. The location of the intravitreal injection in the experimental studies was not precisely known; therefore, several injection locations were considered, and best-fit retinal permeability was determined for each case. Retinal permeability of fluorescein and fluorescein glucuronide estimated by the model ranged from 1.94×10⁻⁵ to 3.5×10⁻⁵ cm s⁻¹ and from 0 to 7.62×10⁻⁷ cm s⁻¹, respectively, depending on the assumed site of the injection. These permeability values were compared with values previously calculated from other models, and the limitations of the models are discussed. Intravitreal injection position was found to be an important variable that must be controlled in both experimental and clinical settings.     

Beneficial Effects of TLR-2/6 Ligation in Pulmonary Bacterial Infection and Immunization with <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis>

Pseudomonas aeruginosa (P. aeruginosa) is the major pathogen in nosocomial and life-threatening infections of immunocompromised or critically ill patients. The macrophage-activating lipopeptide-2 (MALP-2) activates the immune system via Toll-like receptors (TLR) 2 and 6 and leads to an accumulation of immune cells in lungs of young adult (8–10 week old) rats after intratracheal application. This is characterized by a high increase of granulocyte numbers in the BAL 24 h after MALP-2 treatment. It was hypothesized that MALP-2 may have a positive effect on the clinical course of an experimental infection. Therefore, rats were treated with MALP-2 at different time points following an infection with P. aeruginosa. The effect of MALP-2 in combination with immunization with inactivated P. aeruginosa was also investigated. Rats (n = 10) were infected intratracheally (i.t.) with 1 × 10⁸ CFU P. aeruginosa on day 0. They were treated on day −3, −1, 0 and +1 with 2.5 μg MALP-2 or the vehicle i.t. In additional experiments, rats were immunized on day −21 and −14 with 1 × 10⁸ CFU of inactivated P. aeruginosa bacteria and 2.5 μg MALP-2 or vehicle with 1 × 10⁸ CFU of inactivated bacteria and isopropanol. The clinical score, rectal temperature and weight of the rats were checked in both treatment and immunization experiments twice a day. On day 2 they were sacrificed, CFU were determined in the left lung, the right lung being used for histology. In the group treated with MALP-2 1 day prior to infection significant effects were seen: The rectal temperature was about 2°C higher in comparison to the controls at 6 h and also 1 day after infection. Both the symptoms of the infection and the weight loss were significantly reduced. In addition, the CFU and the inflammation in the lung tissue were significantly lower. These effects were not observed after treatment on day −3, 0 or +1. The MALP-2 enhanced immunization only resulted in a tendency to clinical improvement. In conclusion, local immunostimulation at the appropriate time can enhance the host defense against bacteria in the lung.     

Head roll dependent variability of subjective visual vertical and ocular counterroll

We compared the variability of the subjective visual vertical (SVV) and static ocular counterroll (OCR), and hypothesized a correlation between the measurements because of their shared macular input. SVV and OCR were measured simultaneously in various whole-body roll positions [upright, 45° right-ear down (RED), and 75° RED] in six subjects. Gains of OCR were −0.18 (45° RED) and −0.12 (75° RED), whereas gains of compensation for body roll in the SVV task were −1.11 (45° RED) and −0.96 (75° RED). Normalized SVV and OCR variabilities were not significantly different (P > 0.05), i.e., both increased with increasing roll. Moreover, a significant correlation (R ² = 0.80, slope = 0.29) between SVV and OCR variabilities was found. Whereas the gain of OCR is different from the gain of SVV, trial-to-trial variability of OCR follows the same roll-dependent modulation observed in SVV variability. We propose that the similarities in variability reflect a common otolith input, which, however, is subject to distinct central processing for determining the gain of SVV and OCR.     

Forward electrical transmission line model of the human arterial system

A forward mathematical model of the human arterial system, based on an electrical transmission line analogy, has been developed, using a new method for the calculation of peripheral impedance. Simulations of the human arterial system under normal and stenotic arterial conditions were compared with other published simulations, as well as measured clinical data and known clinical quantitative and qualitative characteristics: the harmonic arterial input impedance spectrum demonstrated a mean error of 0.07–0.1 mmHg.s.cm⁻¹, compared with equivalent simulation and physiological data, respectively; qualitative and quantitative variation of blood pressure and flow waveforms along the arterial tree followed clinical trends; arterial pulse wave velocities compared favourably with physiological data close to the aortic root (−50–20 cm s⁻¹ difference), but there were larger differences in the periphery (149–1192 cm s⁻¹ difference); qualitative as well as quantitative variation of blood flow waveforms with progressive stenotic arterial disease, as measured by the pulsatility index, demonstrated an error between 2 and 16% in comparison with mean clinical data for critical stenosis. Under the given test conditions, the forward model was found closely to represent clinically observed haemodynamic characteristics of the human arterial system.     

Haematological and serum biochemical profile of the upside-down catfish, Synodontis membranacea Geoffroy Saint Hilaire from Jebba Lake, Nigeria

Haematological and serum biochemical studies of natural population of Synodontis membranacea from Jebba Lake, North Central Nigeria were investigated in order to establish their mean and reference values. Bi-monthly collection of 1,408 live fish samples was carried out between April 2002 and March 2004, using gill nets of various mesh sizes ranging from 5.08 to 10.16 cm. The mean baseline value established for species-specific haematological and serum biochemical parameters were red blood cell (RBC) 3.83 ± 1.49 × 10¹² l⁻¹, haemoglobin (HB) 8.38 ± 1.96 g dl⁻¹, and packed cell volume (PCV) 25.65 ± 5.89%; mean cell volume 78.25 ± 37.90 fl; mean cell haemoglobin (MCH) 33.04 ± 12.50 pg; mean cell haemoglobin concentration 26.53 ± 15.18 g dl⁻¹; white blood cell (WBC) 315.65 ± 95.37 × 10⁻⁹; agranulocytes (Agr) 82.07 ± 11.38%; monocytes (Mon) 6.37 ± 3.01%; lymphocytes (Lym) 76.49 ± 10.81%; granulocytes (Gran) 40.28 ± 17.48%; neutrophils (Neut) 24.42 ± 10.68%; eosinophils (Eos) 16.14 ± 8.25%; basophils 0.09 ± 0.04%; protein 40.19 ± 7.45 g l⁻¹; albumin 19.78 ± 5.67 g l⁻¹; creatinine 49.71 ± 16.15 μmol l⁻¹; urea 3.05 ± 0.67 nmol l⁻¹; uric acid 0.76 ± 0.33 nmol l⁻¹; glucose 4.24 ± 1.74 mmol l⁻¹; cholesterol 8.46 ± 2.27 mmol l⁻¹; calcium 2.35 ± 0.94 mmol l⁻¹; potassium 13.36 ± 4.45 mmol l⁻¹; sodium 139.39 ± 23.19 mmol l⁻¹; alanine aminotransferase (ALT) 11.79 ± 2.67 U l⁻¹; aspartate aminotransferase 16.80 ± 4.73 U l⁻¹; and alkaline phosphatase 63.01 ± 20.44 U l⁻¹. Only three of these parameters (i.e. neutrophil, glucose and potassium) differed significantly (P > 0.05) on gender basis. Pearson’s correlation coefficients indicated significant relationship of standard length and total weight with RBC, PCV, HB, WBC, Agr, Mon, Lym, Gran, Neut, Eos, sodium, and ALT only. The study has provided baseline haematological and biochemical data for use in health monitoring and productivity of S. membranacea, which would be of great value for future comparative surveys in this era of increased fish culture in Nigeria.     

Apoptosis Inhibitor Expressed by Macrophages Tempers Autoimmune Colitis and the Risk of Colitis-Based Carcinogenesis in TCRα<Superscript>−/−</Superscript> Mice

Background Crohn’s disease and ulcerative colitis (UC) are the two main entities involved in human inflammatory bowel disease (IBD). However, their precise etiologies remain unclear. To study the development of mucosal inflammation, and chronic inflammation-based dysplasia and carcinoma formation, we examined possible roles of the apoptosis inhibitor expressed by macrophages (AIM) in an experimental IBD model. Methods In this study, we used T cell receptor α deficient (TCRα^−/−) mice, a known UC-like colitis model. We generated TCRα^−/− × AIM^−/− double knockout mice by crossbreeding TCRα^−/− with AIM^−/− mice. At 24 weeks of age, mice were killed to obtain colon tissues for pathological examinations. TCRα^−/− × AIM^+/− mice, heterozygous littermates of TCRα^−/− × AIM^−/− mice, were used as controls. Results Severe colitis was observed in TCRα^−/− × AIM^−/− mice, when compared with TCRα^−/− × AIM^+/− mice. Dysplasia was detected in TCRα^−/− × AIM^−/− mice, but not in TCRα^−/− × AIM^+/− mice. Adenocarcinoma formation was observed from dysplasia only in TCRα^−/− × AIM^−/− mice. Conclusion Not only a high incidence of severe colitis but also dysplasia and adenocarcinoma formation were observed in TCRα^−/− × AIM^−/− mice only. AIM have some regulatory roles in inflammation and progression of dysplasia to carcinoma in TCRα^−/− mice.     

Spatial variation of aortic wall oxygen diffusion coefficient from transient polarographic measurements

Polarographic current transients following a voltage step (turn-on transient) were measured with bare cathodes (25 μm diameter) and shallowly recessed oxygen microelectrodes (<5μm diameter). Except for the initial part of the current transient, the experimental measurements were in excellent agreement with simple models in the literature, which predict an inverse relationship with . Turn-on transients were measured in aqueous solutions with known physical properties, and in aortic wall tissue from three different species (n=6 rabbits, n=3 dogs, and n=1 miniature pig). Oxygen diffusion coefficients (D) were determinedin vitro by comparing time constants measured by the same microelectrode in saline and in strips of aortic wall tissue at 37°C. On the inner side (endothelium and intima) of the aorta, D averaged (±S.E.) 7.0 (±0.8)×10⁻⁶ cm²/s in 6 rabbits, 6.4 (±1.0)×10⁻⁶ cm²/s in 3 dogs, and was 4.6×10⁻⁶ cm²/s in the pig. On the adventitial side, D was 9.5×10⁻⁶ cm²/s in 1 rabbit, 11.4 (±1.2)×10⁻⁶ cm²/s in 3 dogs, and 8.1×10⁻⁶ cm²/s in the pig. For every aortic strip on which D was measured from both sides, D for the inner wall was always lower, overall by a little more than one third (p<0.001). The lower D on the endothelial side may limit oxygen transport to the vascular wall and play a role in atherogenesis.