Postmortem Measurements Research Articles

Validation of extravascular lung water measurement by single transpulmonary thermodilution: human autopsy study

IntroductionGravimetric validation of single-indicator extravascular lung water (EVLW) and normal EVLW values has not been well studied in humans thus far. The aims of this study were (1) to validate the accuracy of EVLW measurement by single transpulmonary thermodilution with postmortem lung weight measurement in humans and (2) to define the statistically normal EVLW values.MethodsWe evaluated the correlation between pre-mortem EVLW value by single transpulmonary thermodilution and post-mortem lung weight from 30 consecutive autopsies completed within 48 hours following the final thermodilution measurement. A linear regression equation for the correlation was calculated. In order to clarify the normal lung weight value by statistical analysis, we conducted a literature search and obtained the normal reference ranges for post-mortem lung weight. These values were substituted into the equation for the correlation between EVLW and lung weight to estimate the normal EVLW values.ResultsEVLW determined using transpulmonary single thermodilution correlated closely with post-mortem lung weight (r = 0.904, P < 0.001). A linear regression equation was calculated: EVLW (mL) = 0.56 × lung weight (g) - 58.0. The normal EVLW values indexed by predicted body weight were approximately 7.4 ± 3.3 mL/kg (7.5 ± 3.3 mL/kg for males and 7.3 ± 3.3 mL/kg for females).ConclusionsA definite correlation exists between EVLW measured by the single-indicator transpulmonary thermodilution technique and post-mortem lung weight in humans. The normal EVLW value is approximately 7.4 ± 3.3 mL/kg.Trial registrationUMIN000002780.

Intragranular strain field in columnar ice during transient creep regime and relation with the local microstucture

Transient effects in the creep of polycrystalline ice could play a crucial role for several ice flows (e.g. interaction between Antarctic ice shelves and ocean tides) and also have a major impact concerning deformation mechanisms of ice. During creep de- formation of polycrystalline ice, strong stress and strain-rate intragranular heterogeneities are expected. These heterogeneities come from the very large viscoplastic anisotropy of ice crystals (with essentially a single easy plane for the dislocations to glide) which is responsible for the strong mechanical interaction between adjacent grains (1). In order to go one step further in the quantitative understanding of this process, and to character- ize the development of strain heterogeneities at a microscopic (intragranular) scale, we have performed deformation tests on 2-D polycrystalline ice exhibiting columnar grains with controlled grain size. Specimens were submitted to creep test and transient effects, in which both elastic and viscoplastic responses come in play, are investigated. A Digi- tal Image Correlation (DIC) technique, with spatial resolution far smaller than the mean grain size, has been set to get continuous record of the intragranular displacement field during the test (2). Experimental parameters have been optimized to improve the precision of the DIC results. In parallel, specimen microstructures were analyzed with an automatic ice texture analyzer, before and after deformation, and post-mortem measurements of lo- cal misorientations at the intragranular scale were performed. For the first time in ice, this work presents a direct link between grain orientation, strain localization, and lattice distortion at the intragranular scale.

Feasibility and Short-Term Effects of Biphasic Positive Airway Pressure Versus Assist-Control Ventilation in Preterm Lambs

Biphasic positive airway pressure (BiLevel) ventilation allows utilization of two alternating positive end-expiratory pressures (PEEP) while permitting unrestricted spontaneous breathing with superimposed synchronized pressure support. We aimed to compare whether BiLevel versus assist-control (A-C) ventilation provides effective gas exchange and reduces severity of early lung injury in preterm lambs. Preterm lambs delivered at 134 d (term = 150 d) were quasirandomized to BiLevel (PEEP low/high 5/20 cm H2O) or A-C5 (PEEP 5 cm H2O) ventilation. Ventilation parameters and arterial blood gases were recorded at regular intervals. Postmortem measurements included pressure-volume relationship, lung inflammatory score, wet/dry body weight ratio, and messenger RNA (mRNA) expression of early markers of lung injury. There were no significant differences between groups in baseline characteristics, oxygenation index (p = 0.49), or partial pressure of carbon dioxide (Paco2) (p = 0.08). BiLevel group lambs showed improved pressure-volume relationship (p = 0.006), lower lung inflammatory score (p = 0.013), and trend toward lower messenger RNA expression of markers of lung injury compared with A-C5 group lambs. In unsedated preterm lambs, BiLevel ventilation provides gas exchange equivalent to A-C ventilation and potentially results in reduced lung injury.

Estimating 241Am activity in the body: comparison of direct measurements and radiochemical analyses

The assessment of dose and ultimately the health risk from intakes of radioactive materials begins with estimating the amount actually taken into the body. An accurate estimate provides the basis to best assess the distribution in the body, the resulting dose and ultimately the health risk. This study continues the time-honoured practice of evaluating the accuracy of results obtained using in vivo measurement methods and techniques. Results from the radiochemical analyses of the (241)Am activity content of tissues and organs from four donors to the United States Transuranium and Uranium Registries (USTUR) were compared with the results from direct measurements of radioactive material in the body performed in vivo and post-mortem. Two were whole-body donations and two were partial-body donations. The (241)Am lung activity estimates ranged from 1 to 30 Bq in the four cases. The (241)Am activity in the lungs determined from the direct measurements were within 40% of the radiochemistry results in three cases and within a factor of 2 for the other case. However, in one case the post-mortem direct measurement estimate was a factor of 10 higher than the radiochemistry result for lung activity, most probably due to underestimating the skeletal contribution to the measured count rate over the lungs. The direct measurement estimates of liver activity ranged from 2 to 60 Bq and were consistently lower than the radiochemistry results. The skeleton was the organ with the highest deposition of (241)Am activity in all four cases. The skeletal activity estimates ranged from 30 to 300 Bq. The skeletal activity obtained from measurements over the forehead were within 20% of the radiochemistry results in three cases and differed by 78% in the other case. The results from this study suggest that the measurement methods, data analysis methods and calibration techniques used at the In Vivo Radiobioassay and Research Facility can be used to quantify the activity in the lungs, skeleton and liver when (241)Am activity is present in all three organs. The adjustment method used to account for the contribution from activity in other organs improved the agreement between the direct measurement results and the radiochemistry results for activity in the lungs and skeleton. The method appeared to overestimate the contribution from the other organs to the liver activity measurements, although the low activity levels complicated the analysis. The unadjusted liver activity estimates from the direct measurements were generally in better agreement with the radiochemistry results than the adjusted liver activity. The data from this study indicates that the results from the in vivo measurement techniques provide reasonable estimates of radioactive material in the lungs and skeleton under the most challenging conditions where there is (241)Am activity in multiple organs. The data analysis from additional USTUR cases with both direct measurement results and radiochemistry results is in progress to further evaluate how best to account for the contributions from (241)Am activity in multiple organs and to better understand the uncertainty associated with the adjusted activity.

Can emotional reactivity predict stress responses at slaughter in sheep?

The slaughter period is very complex and may represent different types of stress for the animal. The way and extent animals react to these stress factors depend on their individual emotional reactivity. The objective of the present study was to determine in sheep relationships between reactivity profiles measured during rearing, plasma cortisol levels in blood collected at exsanguination, and metabolic activity in the post-mortem muscle. During the rearing period INRA401 lambs ( n = 267) showed coherence in their responses to situations representing different contexts of novelty, social isolation and presence of man. Vigilance and high-pitched bleating were the most often occurring behaviours. Highest levels of these behaviours were observed during novelty and social isolation. Lambs with higher plasma cortisol levels at exsanguination produced meat with lower pH 3 h ( r = −0.19, p = 0.003) and 24 h post-mortem ( r = −0.13, p = 0.05). Multiple regression analysis found that more socially attracted lambs and lambs performing more high-pitched bleating had higher muscle temperature 3 h post-mortem ( p < 0.001), explaining 23.5% of variability. More vigilant lambs had higher pH ( r = 0.14, p = 0.02) 3 h post-mortem. Multiple regression including both cortisol and vigilance as explanatory variable was significant ( p < 0.01) and explained 12.8% of variability of pH 3 h post-mortem. In the present study, slaughter day, that is, day-to-day variations in the slaughter context, explained 18.4% of the variability in cortisol levels and 25.0–72.7% of variability in post-mortem muscle measurements. When analyses were based on averages per category created according to cortisol levels at exsanguination, to reduce the variability due to slaughter days, behavioural traits (vigilance and social attractiveness of flock-mates) explained statistically about 50% of variability in cortisol levels at exsanguination, and pre-slaughter cortisol levels explained up to 50% of variability of ultimate pH. Relationships between post-mortem muscle metabolism and expressions of social distress and reactivity to novelty suggest that reactivity profile may predict stress reactions during slaughter period and that social disturbances and novel environment in the slaughterhouse may be major causes of stress.

Fatal acute compartment syndrome in patients after surgical treatment: 2 cases report

This report describes 2 cases died from acute compartment syndrome after surgical treatment. Case 1 was a 30-year-old man suffered from upper arm fracture, who complicated with the acute compartment syndrome at the following day after surgical fixation, and died 6 days later. Case 2 was a 9-year-old woman sustained medial malleolus sprain, who experienced plaster cast immobilization and died 7 days after management. At autopsy, swollen and necrotized skeletal muscles with edema were detected in the involved region in both cases. Histopathologically, hemorrhage and infiltration of neutrophils were observed in the skeletal muscles. Intensive positive immunoreactivity of myoglobin was detected in granular casts in distal convoluted tubules by immunohistochemical staining. Marked elevation in serum urea nitrogen uric acid, creatinine and C-reactive protein levels was demonstrated by serological tests. The pathological findings and postmortem biochemical measurements indicated that both victims died due to myoglobinuric renal failure.

Post-mortem measurements of fuel retention at JET with MKII-SRP divertor

The deuterium inventory at JET after 2001–2004 operational campaign has been determined using nuclear reaction analysis (NRA) and secondary ion mass spectrometry (SIMS). A full poloidal set of divertor tiles and a set of outer poloidal limiter (OPL) tiles were analysed providing an estimation for the total deuterium retention of about 66 g. Deuterium is trapped mainly at the inner divertor on horizontal target tile and at the inner divertor louvre area where ∼60% of the trapped D is found. The long-term D retention is ∼4% of the total D input.

Use of ocular fluids to aid postmortem diagnosis in cattle and sheep

THE use of ocular fluids ‐ aqueous humour and vitreous humour ‐ for postmortem diagnosis, especially of hypomagnesaemia, is controversial. This is usually due to an incomplete understanding, or inappropriate...

Prediction of lamb carcass composition and meat quality using combinations of post-mortem measurements

Various post-mortem measurements (carcass weights, conformation and fatness classes, external carcass dimensions, eye muscle dimensions, subcutaneous fat depth, pH and temperature) were recorded on 197 Texel (TEX) and 200 Scottish Blackface (SBF) lamb carcasses. The potential use of these measurements to predict carcass composition and key meat quality traits was investigated, to enable categorisation of carcasses in the abattoir and/or for use in genetic improvement programmes. By combining different measurements, accurate predictions of dissected carcass muscle weight (adjusted R 2 0.93 in TEX, 0.88 in SBF) and fat weight (adjusted R 2 0.84 in TEX, 0.87 in SBF) were achieved, and moderate predictions of intra-muscular fat (adjusted R 2 0.56 in TEX, 0.48 in SBF), whilst shear force was predicted with low to moderate accuracy (adjusted R 2 < 0.33 across breeds and cuts). Sex, eye muscle dimensions and subcutaneous fat depth improved predictions of carcass composition and intra-muscular fat, whilst pH or temperature provided little additional benefit for these traits, but increased prediction accuracies for shear force. These results could contribute to the development of automated carcass grading systems or help inform breeding decisions.

Predicting Longissimusdorsi myoglobin oxidation in aged beef based on early post-mortem colour measurements on the carcass as a colour stability index

Sixty young bulls of the Pirenaica breed, representative of the beef production and marketing system in northern Spain, were used. The carcass grading and weight, pH at 24 h post-mortem, and objective colour measurements (CIE L ∗ a ∗ b ∗) were recorded on the Latissimus dorsi, Rectus abdominis and Longissimus dorsi in order to find indicators and predictors of beef colour stability ( Longissimus dorsi metmyoglobin percentage on ageing for 3, 7 and 14 days) by means of early post-mortem measurements on the carcass. Neither the conformation nor the degree of fattening, under the current EU beef carcass classification system, displayed any statistically significant relationship with colour stability of beef aged 3, 7 and 14 days. However, there was a relationship between the instrumental colour measured on the carcass and the colour stability of the beef. This relationship allowed prediction of colour stability ( Longissimus dorsi MMb percentage) after 3, 7 and 14 days of ageing and 48 h blooming using colour coordinates measured on the carcass.

Post-mortem clinical pharmacology.

Clinical pharmacology assumes that deductions can be made about the concentrations of drugs from a knowledge of the pharmacokinetic parameters in an individual; and that the effects are related to the measured concentration. Post-mortem changes render the assumptions of clinical pharmacology largely invalid, and make the interpretation of concentrations measured in post-mortem samples difficult or impossible. Qualitative tests can show the presence of substances that were not present in life, and can fail to detect substances that led to death. Quantitative analysis is subject to error in itself, and because post-mortem concentrations vary in largely unpredictable ways with the site and time of sampling, as a result of the phenomenon of post-mortem redistribution. Consequently, compilations of 'lethal concentrations' are misleading. There is a lack of adequate studies of the true relationship between fatal events and the concentrations that can be measured subsequently, but without such studies, clinical pharmacologists and others should be wary of interpreting post-mortem measurements.

Transcriptome-Wide Assessment of Human Brain and Lymphocyte Senescence

BackgroundIdentifying biological pathways that vary across the age spectrum can provide insight into fundamental mechanisms that impact disease and frailty in the elderly. Few methodological approaches offer the means to explore this question on as broad a scale as gene expression profiling. Here, we have evaluated mRNA expression profiles as a function of age in two populations; one consisting of 191 individuals with ages-at-death ranging from 65–100 years and with post-mortem brain mRNA measurements of 13,216 genes and a second with 1240 individuals ages 15–94 and lymphocyte mRNA estimates for 18,519 genes.Principal FindingsAmong negatively correlated transcripts, an enrichment of mitochondrial genes was evident in both populations, providing a replication of previous studies indicating this as a common signature of aging. Sample differences were prominent, the most significant being a decrease in expression of genes involved in translation in lymphocytes and an increase in genes involved in transcription in brain, suggesting that apart from energy metabolism other basic cell processes are affected by age but in a tissue-specific manner. In assessing genomic architecture, intron/exon sequence length ratios were larger among negatively regulated genes in both samples, suggesting that a decrease in the expression of non-compact genes may also be a general effect of aging. Variance in gene expression itself has been theorized to change with age due to accumulation of somatic mutations and/or increasingly heterogeneous environmental exposures, but we found no evidence for such a trend here.SignificanceResults affirm that deteriorating mitochondrial gene expression is a common theme in senescence, but also highlight novel pathways and features of gene architecture that may be important for understanding the molecular consequences of aging.

Carcass composition and meat quality of equally mature kids and lambs1

Carcass composition and meat quality attributes of 55 suckling kids (27 males and 28 females) and 57 suckling lambs (28 males and 29 females) of Portuguese native breeds were investigated. These suckling kid and lamb meats are European meat quality labels produced according to "Cabrito de Barroso- PGI" and "Borrego Terrincho-PDO" specifications, respectively. Female kids were slaughtered at 9.1 +/- 0.36 kg of BW, and male kids were slaughtered at 10.4 +/- 0.37 kg of BW, corresponding to 20.1 and 17.7% of maturity, respectively. Female lambs were slaughtered at 8.6 +/- 0.53 kg of BW, and male lambs were slaughtered at 9.9 +/- 0.23 kg of BW, corresponding to 19.9 and 17.1% of maturity, respectively. At 24 h postmortem, various yield and quality measurements were collected. The left sides of the carcasses were dissected into muscle, subcutaneous fat, intermuscular fat, and bone. Final pH, instrumental color (L*, a*, b*), carcass measurements, and kidney knob and pelvic fat were also determined. Samples of LM were taken from the lumbar and thoracic cuts for intramuscular and meat quality determinations. At 72 h postmortem, a sample of LM was used for cooking losses and Warner-Bratzler shear force determination. Suckling lambs had greater dressing proportion than suckling kids (P < 0.01). Carcass fatness was not affected by species (P > 0.05), but females had greater kidney knob and pelvic fat proportion than males (P < 0.01). Lambs had greater proportions of the highly valued leg cut and lower proportions of shoulder, anterior rib, and neck cuts than kids. Dissection results indicated that kid carcasses had greater muscle content and lower dissected fat and bone than lambs. Kids had greater (P < 0.001) muscle ultimate pH value than lambs (5.8 +/- 0.02 vs. 5.6 +/- 0.02). Males had greater (P < 0.05) muscle ultimate pH value than females (5.7 +/- 0.02 vs. 5.6 +/- 0.02). The kid meat was significantly lighter (P < 0.05) and less yellow (P < 0.001) than the lamb meat. Kids presented less cooking losses (P < 0.001) than lambs, and shear force value was significantly greater (P < 0.01) in lamb meat. The kid meat had significantly more moisture (P < 0.001) and less intramuscular fat content (P < 0.001) than lambs. At this maturity stage, there were significant differences on both carcass and meat quality attributes of suckling kids and lambs, possibly due to inherent differences between species.

Rearing oxygen level and slaughter stress effects on rainbow trout flesh quality

Although effects of hypoxia and, in a lower extent, effects of hyperoxia, have been widely studied, very few data is available regarding the effect of oxygen concentration around normoxia. Moreover, the effect of rearing oxygen level around normoxia on flesh quality, and a possible interaction with stress at slaughter, have never been investigated. Rainbow trout were reared during 18 weeks up to pan size (mean weight 400 g) at 76, 98 or 117% of oxygen saturation. Afterwards they were slaughtered according to two procedures: a minimal stress (NS group), or after a 15 min confinement stress (S group). Fish characteristics (weight, condition factor, fat-meter value, plasma cortisol level, hepato-somatic index, and hepatic glycogen content) and quality criteria of fillets (color, initial muscle pH, and muscle glycolytic potential) were recorded at slaughter time, whereas mechanical resistance, ultimate pH and dry matter content of the flesh were measured at 24 h and 48 h post-mortem. Muscle fiber size was analyzed on histological samples from white and red muscles. In our study, rearing oxygen level had no impact on the morphological characteristics of the fish except a higher hepato-somatic index and hepatic glycogen content for trout reared at 97% oxygen saturation. Rearing oxygen level affects slightly flesh quality at the lowest oxygen level (76% saturation) with a lower force for low deformation mechanical resistance measurement in the anterior part of the fillet. Stress before slaughter highly increased plasma cortisol concentration (by more than 18 in mean), and decreased fat-meter values (of 14% in mean) and the mean diameter of red muscle fibers (of 6.4% in mean). Stress before slaughter also decreased fillet lightness ( L⁎, − 1.1 unit), yellowness ( b⁎, − 0.76 unit), and initial pH (− 0.15 unit) of the flesh but had no effect on ultimate pH measured at 24 or 48 h post-mortem. Stress before slaughter induced a softer flesh as shown by lower mechanical resistance at high deformation measured on samples from both anterior and caudal part of the fillet. The post-mortem measurement time (24 or 48 h) was the main factor affecting the mechanical resistance of the flesh, with a significant softening of the flesh between 24 and 48 h. Nor oxygen level, nor slaughter stress affected the size of white muscle fibers. No major interaction between rearing oxygen level and slaughter stress was formally demonstrated.

Evaluation of postmortem measurement of NT-proBNP as a marker for cardiac function

Clinical biomarkers of cardiac function could also be monitored postmortem. Among the natriuretic peptides, the aminoterminal portion of pro-brain natriuretic peptide (NT-proBNP) appears to be a more reliable postmortem tool than the BNP, owing to its longer half-life and greater stability. In living persons, NT-proBNP is considered to be a marker of heart failure, and its level rises after cardiac ischemia. The goal of this study was first to evaluate the postmortem stability of NT-proBNP, then to measure the NT-proBNP levels in postmortem cases of heart failure related to coronary ischemia. The goal of this study was also to evaluate the correlations between different specimens collected at autopsy (e.g. blood, serum, vitreous humor and pericardial fluid). The study included 96 cases, which were classified into 4 groups according to the autopsy and histological findings. The NT-proBNP levels were significantly higher in individuals who had suffered from chronic cardiac ischemia, with or without acute coronary events, than in either control cases or those who had suffered from acute thromboembolism or acute rupture of a plaque without chronic cardiac ischemia. The highest levels were registered in individuals who had suffered from acute coronary thromboembolism in association with chronic coronary ischemia. Good correlations in the NT-proBNP levels for the different specimens were observed between samples of femoral blood, serum, and pericardial fluid. Our data indicated that postmortem measurements of NT-proBNP are reliable and compatible with clinical findings.

Dominance of pre-analytical over analytical variation for measurement of methadone and its main metabolite in postmortem femoral blood

On the basis of simultaneously sampled postmortem blood specimens from the left and right femoral veins the pre-analytical variation of methadone measurements was evaluated and compared to the analytical variation. The material consisted of a series of 27 duplicate samples from routine autopsy cases comprising mainly drug addicts. A chiral LC–MS/MS method was used for measurement of the R- and S-enantiomers of methadone and its main metabolite 2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolinium (EDDP). The analytical CV% was determined to be in the range 3–4% for methadone enantiomers and 4–6% for EDDP enantiomers. The total measurement uncertainty (CV T) was estimated from the pre-analytical variation (CV PA), analytical variation proper (CV A), and variation related to calibration (traceability) (CV Cal) according to the relationship C V T = C V PA 2 + C V A 2 + C V Cal 2 0.5 . Uncertainty related to calibration concerned a component related to the purity of drug reference compound and a contribution from the production of calibrator solutions (CV Cal < 1%). Pre-analytical sampling variation was estimated from the duplicate measurements of blood samples after subtraction of the analytical component. The pre-analytical variation amounted to a CV% of 19–21% for R- and S-methadone and 30–38% for R- and S-EDDP, i.e. considerably larger than the other components. Due to the squared addition principle, the resulting total uncertainty (CV T) became largely identical to the CV PA, i.e. 19–21% for R- and S-methadone and 31–38% for R- and S-EDDP enantiomers. Accordingly, CV T exceeded CV A by a factor 5 or more. Dominance of the pre-analytical component of variation may also be likely for other compounds measured in postmortem blood samples. Thus, the width of the 95%-uncertainty interval (±2 CV T) for a postmortem measurement is largely determined by the pre-analytical component of variation. This should be kept in mind when judging on the uncertainty of postmortem measurement results.

A comparison of the effects of dietary spray-dried bovine colostrum and animal plasma on growth and intestinal histology in weaner pigs

An experiment was conducted to evaluate the effects of dietary spray-dried bovine and porcine plasma and spray-dried bovine colostrum on growth performance and intestinal histology in weaner pigs. Thirty-two 21-day-old piglets (6.65 ± 0.14 kg) were allocated to receive one of four dietary treatments: control, bovine plasma, porcine plasma, and bovine colostrum at weaning and another 8 piglets were killed at weaning to provide baseline data. The experimental diets were offered ad libitum for one week, after which animals were killed and post-mortem measurements obtained. No differences in average daily feed intake and growth rate were observed among dietary treatment groups ( P > 0.05). Baseline piglets had taller villi and shallower crypts ( P < 0.05) in the proximal jejunum, mid jejunum and distal ileum than those observed a week after weaning, irrespective of dietary treatment. Weaning-related expansion of intestinal lamina propria CD4+ and CD8+ T lymphocyte populations was observed ( P < 0.05). Complex and variable treatment effects on villus height, crypt depth, villus and crypt goblet cell density, and lamina propria T cell density were observed, suggesting that the tested protein sources do not share a common or simple mode of action.

Magnetic resonance imaging of mouse skeletal muscle to measure denervation atrophy

We assessed the potential of different MRI measures to detect and quantify skeletal muscle changes with denervation in two mouse models of denervation/neurogenic atrophy. Acute complete denervation and chronic partial denervation were examined in calf muscles after sciatic nerve axotomy and in transgenic SOD1 G93A mice, respectively. Serial T 2, diffusion tensor, and high resolution anatomical images were acquired, and compared to behavioral, histological, and electrophysiological data. Increase in muscle T 2 signal was first detected after sciatic nerve axotomy. Progressive muscle atrophy could be monitored with MRI-based volume measurements, which correlated strongly with postmortem muscle mass measurements. Significant increase in muscle fractional anisotropy and decreases in secondary and tertiary eigenvalues obtained from diffusion tensor imaging (DTI) were observed after denervation. In SOD1 G93A animals, muscle denervation was detected by elevated muscle T 2 and atrophy in the medial gastrocnemius at 10 weeks. Changes in T 2 and muscle volume were first observed in medial gastrocnemius and later in other calf muscles. Alterations in secondary and tertiary eigenvalues obtained from DTI were first observed in tibialis anterior and medial gastrocnemius muscles at age 12 weeks. We propose that MRI of skeletal muscle is a sensitive surrogate outcome measure of denervation atrophy in animal models of neuromuscular disorders, with potential applicability in preclinical therapeutic screening studies in rodents.

Magnetic resonance imaging-based finite element stress analysis after linear repair of left ventricular aneurysm

Linear repair of left ventricular aneurysm has been performed with mixed clinical results. By using finite element analysis, this study evaluated the effect of this procedure on end-systolic stress. Nine sheep underwent myocardial infarction and aneurysm repair with a linear repair (13.4 +/- 2.3 weeks postmyocardial infarction). Satisfactory magnetic resonance imaging examinations were obtained in 6 sheep (6.6 +/- 0.5 weeks postrepair). Finite element models were constructed from in vivo magnetic resonance imaging-based cardiac geometry and postmortem measurement of myofiber helix angles using diffusion tensor magnetic resonance imaging. Material properties were iteratively determined by comparing the finite element model output with systolic tagged magnetic resonance imaging strain measurements. At the mid-wall, fiber stress in the border zone decreased by 39% (sham = 32.5 +/- 2.5 kPa, repair = 19.7 +/- 3.6 kPa, P = .001) to the level of remote regions after repair. In the septum, however, border zone fiber stress remained high (sham = 31.3 +/- 5.4 kPa, repair = 23.8 +/- 5.8 kPa, P = .29). Cross-fiber stress at the mid-wall decreased by 41% (sham = 13.0 +/- 1.5 kPa, repair = 7.7 +/- 2.1 kPa, P = .01), but cross-fiber stress in the un-excluded septal infarct was 75% higher in the border zone than remote regions (remote = 5.9 +/- 1.9 kPa, border zone = 10.3 +/- 3.6 kPa, P < .01). However, end-diastolic fiber and cross-fiber stress were not reduced in the remote myocardium after plication. With the exception of the retained septal infarct, end-systolic stress is reduced in all areas of the left ventricle after infarct plication. Consequently, we expect the primary positive effect of infarct plication to be in the infarct border zone. However, the amount of stress reduction necessary to halt or reverse nonischemic infarct extension in the infarct border zone and eccentric hypertrophy in the remote myocardium is unknown.

Lung compliance measurement in mice

LETTERS TO THE EDITORLung compliance measurement in miceYuh-Chin Tony HuangYuh-Chin Tony HuangPublished Online:01 Apr 2008https://doi.org/10.1152/ajplung.00052.2008MoreSectionsPDF (28 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations to the editor: I read the article by Martin et al. (1) in the September 2007 issue of AJP-Lung. The authors presented interesting observations of increased lung compliance in TIMP-3 null mice during a septic insult. Lung compliance was measured by the linear regression method, the constant phase model, and indirectly by light microscopy morphometry. However, they failed to provide data on static lung compliance using the pressure-volume curve, the gold standard for measuring lung recoil. It would have been an easy postmortem measurement in an open chest mouse using flexiVent. Without the measurement of true lung recoil property, their results remain uncertain.REFERENCE1 Martin EL, Sheikh TA, Leco KJ, Lewis JF, Veldhuizen RA. Contribution of alveolar macrophages to the response of the TIMP-3 null lung during a septic insult. Am J Physiol Lung Cell Mol Physiol 293: L779–L789, 2007.Link | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: Y.-C. Tony Huang, Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, NC 27710 (e-mail: [email protected]) Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByCthrc1 lowers pulmonary collagen associated with bleomycin-induced fibrosis and protects lung function14 March 2017 | Physiological Reports, Vol. 5, No. 5Reply to HuangErica L. Martin, and Ruud A. W. Veldhuizen1 April 2008 | American Journal of Physiology-Lung Cellular and Molecular Physiology, Vol. 294, No. 4 More from this issue > Volume 294Issue 4April 2008Pages L815-L815 Copyright & PermissionsCopyright © 2008 the American Physiological Societyhttps://doi.org/10.1152/ajplung.00052.2008PubMed18391226History Published online 1 April 2008 Published in print 1 April 2008 Metrics