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1.
From Roman gladiatorial combat to Egyptian animal mummies, the capture and manipulation of carnivores was instrumental in helping to shape social hierarchies throughout the ancient world. This paper investigates the historical inflection point when humans began to control animals not only as alimental resources but as ritual symbols and social actors in the New World. At Teotihuacan (A.D. 1–550), one of the largest pre-Hispanic cities, animal remains were integral components of ritual caches expressing state ideology and militarism during the construction of the Moon and the Sun Pyramids. The caches contain the remains of nearly 200 carnivorous animals, human sacrificial victims and other symbolic artifacts. This paper argues the presence of skeletal pathologies of infectious disease and injuries manifest on the carnivore remains show direct evidence of captivity. Stable isotope analysis (δ13C and δ15N) of bones and teeth confirms that some of these carnivores were consuming high levels of C4 foods, likely reflecting a maize-based anthropocentric food chain. These results push back the antiquity of keeping captive carnivores for ritualistic purposes nearly 1000 years before the Spanish conquistadors described Moctezuma’s zoo at the Aztec capital. Mirroring these documents the results indicate a select group of carnivores at Teotihuacan may have been fed maize-eating omnivores, such as dogs and humans. Unlike historical records, the present study provides the earliest and direct archaeological evidence for this practice in Mesoamerica. It also represents the first systematic isotopic exploration of a population of archaeological eagles (n = 24) and felids (n = 29).  相似文献   

2.
This paper examines competing theories for cases in which both the data and the hypotheses can be represented as distance matrices. A test due to Dow & Cheverud has been used for such comparisons in anthropology, but when data are spatially, temporally, or phylogenetically autocorrelated, this test may be far too liberal. We examine a classification procedure based on ratios of probabilities obtained from Mantel tests of the competing hypotheses and find that design matrices describing only lag-one connections and those eliminating common connections of competing hypotheses are the most informative. We apply this method to simulated gene-frequency data in a 7×7 chessboard representing a stepping-stone model and discriminate between alternative theories with a 7% misclassification rate. We also apply these techniques to the current controversy concerning the origin of anatomically modern humans by testing design matrices representing regional continuity and single African origins. The outcome for lag-one matrices and those showing only unique lag-one differences indicate that the single African origin of anatomically modern humans fits the distance matrix based on 165 characters of 83 fossil crania better than the competing theory. However, we also tested a design matrix describing single origin out of southwest Asia. This design matrix was clearly most similar to the data in all tested cases. These results make the regional-continuity theory a less likely explanation for the observed cranial differences than the two single-origin theories. Of these, single southwest Asian origins seems the more likely interpretation of the data.  相似文献   

3.
Hawksbill turtles (Eretmochelys imbricata) migrate between nesting beaches and feeding habitats that are often associated with tropical reefs, but it is uncertain which nesting colonies supply which feeding habitats. To address this gap in hawksbill biology, we compile previously published and new mitochondrial DNA (mtDNA) haplotype data for 10 nesting colonies (N = 347) in the western Atlantic and compare these profiles to four feeding populations and four previously published feeding samples (N = 626). Nesting colonies differ significantly in mtDNA haplotype frequencies (Phi(ST) = 0.588, P < 0.001), corroborating earlier conclusions of nesting site fidelity and setting the stage for mixed-stock analysis. Feeding aggregations show lower but significant structure (Phi(ST) = 0.089, P < 0.001), indicating that foraging populations are not homogenous across the Caribbean Sea. Bayesian mixed-stock estimates of the origins of juveniles in foraging areas show a highly significant, but shallow, correlation with nesting population size (r = 0.378, P = 0.004), supporting the premise that larger rookeries contribute more juveniles to feeding areas. A significant correlation between the estimated contribution and geographical distance from nesting areas (r = -0.394, P = 0.003) demonstrates the influence of proximity on recruitment to feeding areas. The influence of oceanic currents is illustrated by pelagic stage juveniles stranded in Texas, which are assigned primarily (93%) to the upstream rookery in Yucatan. One juvenile had a haplotype previously identified only in the eastern Atlantic, invoking rare trans-oceanic migrations. The mixed-stock analysis demonstrates that harvests in feeding habitats will impact nesting colonies throughout the region, with the greatest detriment to nearby nesting populations.  相似文献   

4.
The molecular bases of Alzheimer's disease (AD) remain unclear. We used a lipidomic approach to identify lipid abnormalities in the brains of subjects with AD (N = 37) compared to age-matched controls (N = 17). The analyses revealed statistically detectable elevations in levels of non-esterified monounsaturated fatty acids (MUFAs) and mead acid (20:3n-9) in mid-frontal cortex, temporal cortex and hippocampus of AD patients. Further studies showed that brain mRNAs encoding for isoforms of the rate-limiting enzyme in MUFAs biosynthesis, stearoyl-CoA desaturase (SCD-1, SCD-5a and SCD-5b), were elevated in subjects with AD. The monounsaturated/saturated fatty acid ratio ('desaturation index')--displayed a strong negative correlation with measures of cognition: the Mini Mental State Examination test (r = -0.80; P = 0.0001) and the Boston Naming test (r = -0.57; P = 0.0071). Our results reveal a previously unrecognized role for the lipogenic enzyme SCD in AD.  相似文献   

5.
We examine surname distribution, origin, and association with Y-chromosome haplogroups in native communities from the Aleutian archipelago. The underlying hypothesis is that surnames and Y-chromosome haplogroups should be associated because both are paternally inherited markers. We used Lasker's coefficient of relationship through isonymy (R(ib) ) to identify the distribution of 143 surnames in the Aleutian Islands. The geographic distribution of surnames was explored both through frequency distribution and through the use of Mantel tests. Multidimensional scaling, chi-square, and Mantel tests were used to examine the relationship between surname and Y-chromosome markers. Overall, we observed that the distribution of surnames in the Aleutian archipelago is culturally driven rather than being one of paternal inheritance. Surnames follow a gradient from east to west, with high frequencies of Russian surnames found in western Aleut communities and high levels of non-Russian surnames found in eastern Aleut communities. A nonsignificant correlation (r = -0.0132; P = 0.436) was found between distance matrices based on haplogroups of the nonrecombining portion of the Y chromosome and surnames, although an association was found between non-Russian surnames and the predominantly non-Russian haplogroups (R1b, I1a, and I).  相似文献   

6.
Monoamine oxidase-B (Mao-B) catalysing the breakdown of the neurotransmitter dopamine, is known to be involved in the pathophysiology of Parkinson's (PD) and Alzheimer's disease (AD). Increased brain Mao-B activity is associated with AD. This alteration can also be seen in platelets, albeit the cause has hitherto remained elusive. To gain a deeper understanding of the etiology of AD, the platelet proteome was characterised, (2D DIGE pH6-9, including Mao-B) from 150 individuals: 34 AD, 13 vascular dementia, 15 non-demented PD patients, 49 matched controls, 18 oldest old and 21 young individuals. One significant change was noted after applying false discovery rate with the upregulation of the Mao-B expression (30% adjusted P value<0.001; effect size 1.31) in AD compared to age- and sex-matched controls. In contrast, Mao-B levels were unchanged in PD to matched controls. Western blot and mRNA analyses verified these findings. Moreover, Mao-B concentration correlated with age in the cognitive healthy individuals (r=0.53; P<0.001) and PD patients but not in those suffering from AD (r=-0.03; P=0.874). Mao-B activity correlated with the increased Mao-B protein expression in AD (r=0.81; P=0.016). We suggest that Mao-B platelet protein level may serve as a biomarker for age-related dementia, especially AD.  相似文献   

7.
This investigation addresses two related questions about the origins and biological affinities of the Canary Islands' aboriginal inhabitants. First: With which North African populations do the pre-conquest inhabitants of the Canary Islands have their greatest affinities? Second: Does inter-island biological variability among the Canary Islanders, as has been suggested by other researchers (Hooton 1925, Schwidetzky 1963), imply that potentially different founding populations remained distinct during the pre-conquest period? This study employs dental morphology data derived from pre-conquest skeletons to answer these questions. Non-metric dental traits appear to be controlled by polygenic systems with a low to moderate environmental contribution to the resulting phenotype (Berry 1978, Harris & Bailit 1980, Nichol 1990) and can thus be assumed to reflect genetic relationships. The dental morphology of a sample of Canary Islanders (n = 397) is compared to that of Northwest African samples of Algerian Shawia Berbers (n = 26), Kabyle Berbers (n = 32), Bedouin Arabs (n = 49) and Punic Carthaginians (n = 28) as well as to six samples from Northeast Africa (n = 307) included for the purpose of understanding Canary Islanders' affinities within a wider context. The analysis employs 28 dental traits, quantifying differences in their expression among the various samples through a summary statistic, CAB Smith's Mean Measure of Divergence (MMD). The MMD analysis indicates that the Canary Island sample is most similar to the four samples from Northwest Africa: the Shawia Berbers, Kabyle Berbers, Bedouin Arabs and Carthaginians, less similar to the three Egyptian samples and least like the three Nubian samples. An intra-island comparison among samples from La Gomera, Gran Canaria and Tenerife reveals low, insignificant MMD values in all cases, implying that inter-island dental morphology differences are not so great as to require hypotheses of separate founding populations.  相似文献   

8.
The genetic structure of La Cabrera (province of Léon, Spain), a highly isolated and inbred population (alpha3 = 0.00482), is analyzed by applying multivariate methods (nonmetric multidimensional scaling, Mantel test, Monmonier's algorithm) to different biodemographic data sets. Isonymy, parent-offspring migration (total, males, females), and marital migration matrices were obtained from 5,714 marriages recorded in 37 parishes (clustered in 4 municipalities) between 1880 and 1989. The aim of the study is to investigate the relationships between the genetic and geographic structures of the area. Endemicity values (diagonal of parent-offspring migration matrices), calculated for both sexes at two hierarchical levels (parishes and municipalities), show that female mobility follows the virilocal migration model at the higher (municipalities) level and the uxorilocal model at the parish level. Analysis of isonymy and parent-offspring migration matrices shows high correspondence between the genetic structure and geographic location of the parishes. In fact, the main reproductive barriers, constructed using Monmonier's algorithm, generally coincide with geographic barriers, highlighting increasing isolation patterns from northwest to southeast. Moreover, the analysis of isonymous relationships, which are influenced by earlier population movements, identifies three parishes whose outlier positions are explained by historical-cultural or geographic reasons. The positive and highly significant values (0.32 < or = r < or = 0.51;p < or = 0.001) given by the Mantel tests underline the dependence of the genetic structure on geographic distance. In confirmation of the endemicity results, the lowest correlation value (r = 0.32) is given by the female migration matrix. When the outlier parishes are omitted from the analysis, the correlation between isonymy and geographic distance increases from 0.35 to 0.46, and the values from the other migration matrices remain unchanged. In conclusion, the combination of different data sets and methods allows a wider and more coherent reconstruction of the historical changes in the genetic structure of the La Cabrera population.  相似文献   

9.
Epithelial-mesenchymal transition (EMT) is characterized by the loss of epithelial cell junction proteins and the gain of mesenchymal markers. The aim of this study was to analyze the associations between the EMT-related markers vimentin, E-cadherin, β-catenin, slug, snail, and twist1 and clinicopathologic parameters as well as epidermal growth factor receptor (EGFR) gene copy number and protein expression in non-small cell lung carcinoma (NSCLC). Fifty-nine squamous cell carcinomas (SCC) and 43 adenocarcinomas (AD) were immunohistochemically examined for respective EMT markers and for EGFR, using the EGFR PharmDx kit (Dako) for protein expression and automated silver enhanced in situ hybridization (SISH) for copy number. Vimentin expression in tumor epithelia was significantly higher in AD samples than in SCC samples (P=0.015). Among AD samples, vimentin expression was positively correlated with histologic grade (2 vs. 3; P=0.021) and exhibited a tendency toward a positive correlation with pTNM stage (I vs. II-IV; P=0.052). EGFR gene copy number was positively correlated with EGFR protein expression among both AD samples (P=0.008) and SCC samples (P=0.042), with EGFR protein expression being significantly higher in SCC samples compared with AD (P=0.038). Among AD samples, EGFR protein expression was associated with higher cytoplasmic expression of β-catenin (P=0.031). Among SCC samples, EGFR protein expression was negatively correlated with nuclear expression of β-catenin (P=0.033) but positively with nuclear slug (P=0.021). The expression pattern of EMT markers in AD suggests that vimentin is a possible immunohistochemical predictor of tumor progression.  相似文献   

10.
The regulation of telomere length (TL) is a complex process, requiring the telomerase enzyme complex and numerous regulatory proteins. Epigenetic regulation may also be important in telomere maintenance. Specifically, methylation at subtelomeres is associated with changes in TL in vitro and in mouse models. Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome characterized by exceedingly short telomeres and mutations in telomere biology genes. To understand the interaction between methylation and TL in humans, we measured LINE-1, pericentromeric (NBL2), and subtelomeric (D4Z4) methylation in peripheral blood DNA derived from 40 patients with DC and 51 mutation-negative relatives. Pearson's correlation coefficient and linear regression models were used to evaluate the relationship between age-standardized lymphocyte TL measured by flow FISH and % DNA methylation. No differences in % subtelomeric, LINE-1, or pericentromeric methylation between patients with DC and relatives were noted except for an increase in % subtelomeric methylation in DC patients with a telomerase-complex mutation (TERC, TERT, DKC1, or TCAB1) (63.0% in DC vs. 61.8% in relatives, P = 0.03). Positive correlations between TL and DNA methylation at LINE-1 (r = 0.39, P = 0.01) and subtelomeric (r = 0.32, P = 0.05) sites were present in patients with DC. The positive correlation between TL and % LINE-1 methylation was restricted to TINF2 mutations. In contrast, statistically nonsignificant inverse correlations between TL and % LINE-1 (r = -0.17), subtelomeric (r = -0.20) were present in unaffected relatives. This study suggests an interaction between TL and both subtelomeric and LINE-1 methylation, which may be altered based on mutation status of telomere biology genes.  相似文献   

11.
The value of CD30 and the soluble circulating fragment of CD30 (sCD30) for atopic dermatitis (AD) remains unclear. In particular, little is known about the effects of age, duration of disease and Scoring Atopic Dermatitis index (SCORAD) on the levels of serum sCD30 in patients affected by AD. In the present study, we have analysed serum sCD30 levels of adult patients affected by AD. The study's population includes 18 non-smoking outpatients, with a diagnosis of AD. As a control group we studied 18 non-atopic subjects from laboratory staff, matched for sex and age. These subjects had no history of AD, urticaria or seasonal or perennial rhinitis or asthma, and had negative skin prick test to a panel of allergens. The sCD30 serum levels were clearly higher in patients affected by AD (14.2+/-9.0 IU/ml) than in healthy subjects (1.2+/-0.8 IU/ml) (p<0.001). No differences were observed between males and females affected by atopic dermatitis, regarding age, duration of disease and SCORAD. Significant correlations were found between serum levels of sCD30 levels and age (r=-0.55; 95% confidence interval (CI) for r (Fisher's z transformed)=-0.81 to -0.12; p=0.01), duration of the disease (months) (r=-0.64; 95% CI for r (Fisher's z transformed)=-0.85 to -0.24; p=0.004) and SCORAD (r=-0.74; 95% CI for r (Fisher's z transformed)=-0.89 to -0.42; p=0.004). As demonstrated by the close correlation with age, duration of disease and SCORAD, serum levels of sCD30 appear to be an additional marker for the follow-up of AD.  相似文献   

12.
One of the candidate genes for suicide is also a gene in the pathway for catecholamine degradation encoding an enzyme catechol-O-methyl-transferase (COMT). It harbors a common functional polymorphism, a G to A nucleotide transition resulting in amino acid substitution from valine (Val) to methionine (Met) at position 158 (COMT Val(108/158) Met; rs4680), that has been associated with psychiatric disorders characterized with an increased risk of suicidal behavior. We have performed the first study on Caucasian population examining the association between completed suicide and the COMT Val(108/158) Met polymorphism. The study population consisted of 356 suicide victims and 198 control subjects. Significant difference in COMT Val(108/158) Met variants' (genotypes, alleles and Val carriers) distribution was found only in male groups, between controls and suicide victims (P = 0.018, P = 0.031, P = 0.005), and between controls and violent suicide victims (P = 0.026, P = 0.042, P = 0.010). The r value from the standardized residuals showed that the Met/Met genotype (r = 2.03) in the control group contributed to these significant differences. In contrast to male subjects, no significant differences in the frequency of the COMT Val(108/158) Met variants were detected between female control and female suicide groups; however, the power of calculation (range 0.161-0.680) was below the desired 0.800. In addition, the logistic regression analysis confirmed these significant differences. In conclusion, our results showed the overpresentation of the Met/Met genotype in male control subjects compared with male suicide victims, suggesting that this genotype of the COMT Val(108/158) Met might be a protective factor against suicide.  相似文献   

13.
Dung beetles (Scarabaeinae y Aphodiinae) were used to evaluate the effects of human activities in the area surrounding La Planada Natural Reserve, southwestern Colombia. During 1993 we monitored three habitats: primary and secondary forest, and open fields used for cattle grazing. A total of 55,296 trap/hours, evenly distributed among the three habitat types, captured 9,115 individuals (18 species, 11 genera). There were differences in species richness between habitats (F2,9 = 29.88; P < 0.001), an in number of individuals (F 2,9 = 36.22; P < 0.001). Collecting sites differed within habitats. Cluster analyses show that species composition differs between habitats with and without tree cover. Open areas act as barriers for movements of forest species. Differences between habitats and collecting sites may reflect high environmental heterogeneity, land use history of the sites or the influence of nearby disturbance. Some of the species found in open fields come from lower elevations and are usually associated with intense human disturbance. The proportion of digging and rolling species is similar in both primary and secondary forest, nocturnal species are more abundant; in open areas rolling species are absent and the number of diurnal species increases. We found no relationship between rainfall and species richness (r2 = 0.26; P = 0.41), nor between rainfall and number of individuals collected throughout the year (r2 = 0.07; P = 0.84). For all species the number of individuals collected decreased during dry season and during the onset of the rainy season.  相似文献   

14.
Matrix correlation represents an innovative methodology to evaluate the explanatory power of several hypotheses by measuring their correspondence with observed morphological variation. In this paper, we view the origins of Patagonians from a matrix correlation approach. Personal and published data on nonmetric cranial traits were used to estimate a biological distance matrix involving five major groups from Patagonia and two from the northwest and northeast regions of Argentina. To evaluate correspondence with other important factors, we used a geographic distance matrix and four design matrices, representing several patterns of settlement and differentiation. Biological distance was found to be strongly associated with spatial separation; the correlation between geography and nonmetric cranial distances was highly significant. When geographic distance is held constant, correlation between a model representing high levels of heterogeneity between the samples and morphological (nonmetric) variation becomes highly significant.  相似文献   

15.
The relationship of whole blood selenium (Se) to glutathione peroxidase (GPX) activity was examined for individuals in New Zealand, Oregon, and South Dakota who represented, respectively, populations with exposure to low, medium, and high amounts of Se. The mean (respective) blood Se levels were 60, 200, and 400 ng/ml. Intergroup differences in blood Se levels were highly significant (P less than 0.001). GPX assays were performed using two variations of an enzyme-coupled procedure to assess the equivalence of the two methods. Despite a fourfold difference in absolute activities measured by these methods, the GPX activities were highly correlated (r = .86) between procedures. Average blood GPX activity was significantly lower (P less than 0.001) for the New Zealand group compared with the other two groups, but there was no difference in GPX activities between the Oregon and South Dakota groups. Linear regression of GPX vs. Se values within each group indicated a significant correlation of these parameters only in the New Zealand group (r = .46, P less than 0.01). Comparison of these parameters for combined data from all three groups also showed a significant positive correlation (r = .60, P less than 0.001). A saturation model (In GPX = k1 + k2 (Se)-1)) fits the combined data better (r = .80, P less than 0.01) than does direct comparison of the two parameters. These results suggest that GPX activity is an appropriate indicator of human Se status only in populations with below normal exposure to Se, as activity of this enzyme is saturated at relatively low levels.  相似文献   

16.
Among the several linkage disequilibrium measures known to capture different features of the non-independence between alleles at different loci, the most commonly used for diallelic loci is the r(2) measure. In the present study, we tackled the problem of the bias of r(2) estimate, which results from the sample structure and/or the relatedness between genotyped individuals. We derived two novel linkage disequilibrium measures for diallelic loci that are both extensions of the usual r(2) measure. The first one, r(S)(2), uses the population structure matrix, which consists of information about the origins of each individual and the admixture proportions of each individual genome. The second one, r(V)(2), includes the kinship matrix into the calculation. These two corrections can be applied together in order to correct for both biases and are defined either on phased or unphased genotypes.We proved that these novel measures are linked to the power of association tests under the mixed linear model including structure and kinship corrections. We validated them on simulated data and applied them to real data sets collected on Vitis vinifera plants. Our results clearly showed the usefulness of the two corrected r(2) measures, which actually captured 'true' linkage disequilibrium unlike the usual r(2) measure.  相似文献   

17.

Purpose

To investigate the potential of diffusion tensor imaging (DTI) parameters as in-vivo biomarkers of axon and myelin sheath integrity of the median nerve in the carpal tunnel as validated by correlation with electrophysiology.

Methods

MRI examinations at 3T including DTI were conducted on wrists in 30 healthy subjects. After manual segmentation of the median nerve quantitative analysis of fractional anisotropy (FA) as well as axial, radial and mean diffusivity (AD, RD, and MD) was carried out. Pairwise Pearson correlations with electrophysiological parameters comprising sensory nerve action potential (SNAP) and compound muscle action potential (CMAP) as markers of axon integrity, and distal motor latency (dml) and sensory nerve conduction velocity (sNCV) as markers of myelin sheath integrity were computed. The significance criterion was set at P=0.05, Bonferroni corrected for multiple comparisons.

Results

DTI parameters showed a distinct proximal-to-distal profile with FA, MD, and RD extrema coinciding in the center of the carpal tunnel. AD correlated with CMAP (r=0.50, p=0.04, Bonf. corr.) but not with markers of myelin sheath integrity. RD correlated with sNCV (r=-0.53, p=0.02, Bonf. corr.) but not with markers of axon integrity. FA correlated with dml (r=-0.63, p=0.002, Bonf. corr.) and sNCV (r=0.68, p=0.001, Bonf. corr.) but not with markers of axon integrity.

Conclusion

AD reflects axon integrity, while RD (and FA) reflect myelin sheath integrity as validated by correlation with electrophysiology. DTI parameters consistently indicate a slight decrease of structural integrity in the carpal tunnel as a physiological site of median nerve entrapment. DTI is particularly sensitive, since these findings are observed in healthy participants. Our results encourage future studies to evaluate the potential of DTI in differentiating axon from myelin sheath injury in patients with manifest peripheral neuropathies.  相似文献   

18.
目的探究补充维生素D联合益生菌治疗多囊卵巢综合征(PCOS)对患者菌群多样性、代谢和激素水平的影响。方法选取2019年1月至2019年3月在东南大学附属中大医院诊断并治疗的PCOS患者60例,采用随机数表法分为联合补充组(30例)和维生素D组(30例),联合补充组同时使用维生素D和益生菌,维生素D组只补充维生素D。对治疗前后患者肠道菌群进行检测,并比较代谢因子和激素水平,使用Pearson相关性分析探究指标间的相关性。结果治疗后两组菌群丰富度、Shannon-Wiener指数及最大Shannon-Wiener指数均较治疗前显著升高(均P<0.05),且联合补充组丰富度、Shannon-Wiener指数显著高于维生素D组(t=4.496,2.896,均P<0.05);治疗后两组GSH、TAC水平均显著升高,其中联合补充组TAC显著高于维生素D组(t=2.505,P=0.002);治疗后两组MDA、TT显著降低,其中联合补充组MDA、TT显著低于维生素D组(t=2.371,2.177,P=0.021,0.034)。副拟杆菌属与MDA呈显著正相关(r=0.339,P=0.040),肠杆菌科与TT呈显著正相关(r=0.330,P=0.046),粪杆菌属与TAC呈显著正相关(r=0.437,P=0.007),乳杆菌属与TAC呈显著正相关(r=0.350,P=0.033),与TT呈显著负相关(r=-0.371,P=0.024)。结论补充维生素D联合益生菌可有效改善PCOS患者代谢因子及激素水平,且其肠道微生物与PCOS代谢及激素指标存在一定相关性。  相似文献   

19.
Regional and global relationships of lung function and structure were studied using hyperpolarized 3He MRI in a rat elastase-induced model of emphysema (n = 4) and healthy controls (n = 5). Fractional ventilation (r) and apparent diffusion coefficient (ADC) of 3He were measured at a submillimeter planar resolution in ventral, middle, and dorsal slices 6 mo after model induction. Pulmonary function testing (PFT) was performed before MRI to yield forced expiratory volume in 50 ms (FEV??), airway resistance (R(I)), and dynamic compliance (C(dyn)). Cutoff threshold values of ventilation and diffusion, r* and ADC*, were computed corresponding to 80% population of pixels falling above or below each threshold value, respectively. For correlation analysis, r* was compared with FEV??/functional residual capacity (FRC), R(I) and C(dyn), whereas ADC* was compared with FEV??/FRC, total lung capacity (TLC), and C(dyn). Regional correlation of r and ADC was evaluated by dividing each of the three lung slices into four quadrants. C(dyn) was significantly larger in elastase rats (0.92 ± 0.16 vs. 0.61 ± 0.12 ml/cmH?O). The difference of R(I) and FEV?? was insignificant between the two groups. The r* of healthy rats was significantly larger than the elastase group (0.42 ± 0.03 vs. 0.28 ± 0.06), whereas ADC* was significantly smaller in healthy animals (0.27 ± 0.04 vs. 0.36 ± 0.01 cm2/s). No systematic difference in these quantities was observed between the three lung slices. A significant 33% increase in ADC* and a significant 31% decline in r* for elastase rats was observed compared with a significant 51% increase in C(dyn) and a nonsignificant 26% decline in FEV??/FRC. Correlation of imaging and PFT metrics revealed that r and ADC divide the rats into two separate clusters in the sample space.  相似文献   

20.
Dual-energy X-ray absorptiometry (DEXA) provides a measure of lean soft tissue (LST). LST hydration, often assumed to be constant, is relevant to several aspects of DEXA body composition estimates. The aims of this study were to develop a theoretical model of LST total body water (TBW) content and to examine hydration effects with empirically derived model coefficients and then to experimentally test the model's prediction that, in healthy adults, LST hydration is not constant but varies as a function of extra- and intracellular water distribution (E/I). The initial phase involved TBW/LST model development and application with empirically derived model coefficients. Model predictions were then tested in a cross-sectional study of 215 healthy adults. LST was measured by DEXA, extracellular water (ECW) by NaBr dilution, intracellular water (ICW) by whole body (40)K counting, and TBW by (2)H(2)O dilution. TBW estimates, calculated as ECW + ICW, were highly correlated with (r = 0.97, SEE = 2.1 kg, P < 0.001) and showed no significant bias compared with TBW measured by (2)H(2)O. Model-predicted TBW/LST was almost identical to experimentally derived values (means +/- SD) in the total group (0.767 vs. 0.764 +/- 0.028). LST hydration was significantly correlated with E/I (total group, r = 0.30, SEE = 0.027, P < 0.001). Although E/I increased with age (men, r = 0.48; women, r = 0.37; both P < 0.001), the association between TBW/LST and age was nonsignificant. Hydration of the DEXA-derived LST compartment is thus not constant but varies predictably with ECW and ICW distribution. This observation has implications for the accuracy of body fat measurements by DEXA and the use of TBW as a means of checking DEXA system calibration.  相似文献   

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