Tissue 4

The finding that there are considerable tissue stresses (TSs)in the hypocotyl of Helianthus annuus L. prompts the question:how are the stresses generated? Here, a one-dimensional modelis formulated which, based on (i) symplastic, turgor-inducedextensions of tissues which differ in moduli of elasticity,and (ii) static equilibrium, predicts the occurrence of longitudinalTSs in stem-like organs, and gives their dependence on turgorpressure. To calculate the longitudinal forces which generatethe TSs in a stem, the moduli of elasticity of the tissues needto be known. The moduli were determined for uniaxial and multiaxialstresses for the outer tissue (OT) and the inner tissue (IT)of the hypocotyl. In the OT, the moduli were strongly dependenton applied uniaxial stress. The magnitudes of the calculatedlongitudinal forces (tensile and compressive) in the hypocotyl,were comparable to those measured. It follows that the TSs mayarise without differential growth of the tissues. Key words: Epidermis, model, moduli of elasticity, turgor, sunflower hypocotyl, tissue stresses     

Catechol Oxidase in Tissue 4

Catechol oxidase activity in tissue culture of apple fruit wasfollowed during growth. Enzyme activity was not found to becorrelated with the growth of the cultures. Cnltures with initiallyhigh enzyme activity show a lag in growth while enzyme activitydeclines. In cultures with an initial low activity, rapid growthis followed by an increase in enzyme activity which declinesagain as growth slows down. As the tissue ages, a greater proportionof enzyme activity is found in the soluble part of the cell. Low concentrations of O₂, lowered sucrose concentrations, orraised NaCl concentrations in the medium depress growth of theculture rapidly, while their effect on enzyme activity is delayed. Rapid desiccation of the tissue causes a large increase in enzymeactivity, possibly by activation, within 20 h. The subcollulardistribution of enzyme is changed at the same time.     

The Effect of 2: 4-Dinitrophenol on the Respiration of Apple Tissue 3

The respiration of pre-climacteric apple pulp but not peel tissuecan be stimulated by addition of DNP. Post-climacteric pulpand peel tissue cannot be stimulated by addition of DNP. The disappearance of DNP stimulation of pulp tissue respiration,and also the development of a malate-decarboxylating systemin the peel, are closely associated with the respiration climactericin the whole fruit.     

The Influence of External Concentration on Sodium Ion Absorption by Carrot Root Tissue 4

The influence of external concentration on sodium ion absorptionby slowly and rapidly growing carrot root tissue cultures hasbeen examined. In conflict with the observations of Stewardand Millar (1954) it is observed that absorption by the twokinds of cultures is affected similarly by external concentration.The discrepancy between the two investigations is discussedand an alternative interpretation of the results of Stewardand Millar is proposed.     

4D Multi-Modality Tissue Segmentation of Serial Infant Images

Accurate and consistent segmentation of infant brain MR images plays an important role in quantifying patterns of early brain development, especially in longitudinal studies. However, due to rapid maturation and myelination of brain tissues in the first year of life, the intensity contrast of gray and white matter undergoes dramatic changes. In fact, the contrast inverse around 6–8 months of age, when the white and gray matter tissues are isointense and hence exhibit the lowest contrast, posing significant challenges for segmentation algorithms. In this paper, we propose a longitudinally guided level set method to segment serial infant brain MR images acquired from 2 weeks up to 1.5 years of age, including the isointense images. At each single-time-point, the proposed method makes optimal use of T1, T2 and the diffusion-weighted images for complimentary tissue distribution information to address the difficulty caused by the low contrast. Moreover, longitudinally consistent term, which constrains the distance across the serial images within a biologically reasonable range, is employed to obtain temporally consistent segmentation results. Application of our method on 28 longitudinal infant subjects, each with 5 longitudinal scans, shows that the automated segmentations from the proposed method match the manual ground-truth with much higher Dice Ratios than other single-modality, single-time-point based methods and the longitudinal but voxel-wise based methods. The software of the proposed method is publicly available in NITRC (http://www.nitrc.org/projects/ibeat).     

The Hypersensitive Reaction in Tobacco Leaf Tissue infiltrated with Pseudomonas pisi 4. Scanning Electron Microscope Studies on fractured Leaf Tissue

Leaves of tobacco infiltrated with Pseudomonas pisi were fractured at various times during the course of the hypersensitive reaction to expose cell surfaces within the tissue and mesophyll cell contents. Scanning electron microscopy of cross-fractured mesophyll cells did not reveal any gross change in internal structure during the reaction induction period (0—2 h), but breakdown of tonoplast and collapse of chloroplasts commenced at about 5 h, during the latent period. Death of the mesophyll cells was followed by condensation of cell contents, and pronounced stretching of cell walls, due to desiccation and shrinkage.Between 0—6 h after infiltration, bacteria were largely confined to cell junctions, frequently within droplets. With collapse of the host cells and release of cell fluid, numbers of bacteria increased considerably (many dividing cells), and there was a shift of bacterial distribution to the whole mesophyll cell surface. The progressive desiccation that occurred between 10—20 h prevented further bacterial increase, but numbers of bacteria remained stable. Death of bacteria commenced at about 15 h, and was accompanied by the formation of numerous surface protrusions, which detached and deposited over the whole mesophyll surface.     

Bacteriological Survey of Raw Beef Patties Produced at Establishments Under Federal Inspection

At the time of manufacture, 76% of 74 sets of raw beef patties collected in 42 federally inspected establishments had aerobic plate counts of 1,000,000 or fewer/g; 84% contained 100 or fewer coliforms/g; 92% contained 100 or fewer Escherichia coli/g; and 85% contained 100 or fewer Staphylococcus aureus/g (geometric means of 10 patties/set). Salmonellae were isolated from only three (0.4%) of 735 beef patties.     

The Use of Human Tissue

The use of human tissue raises ethical issues of great concern to health care professionals, biomedical researchers, ethics committees, tissue banks and policy makers because of the heightened importance given to informed consent and patient autonomy. The debate has been intensified by high profile scandals such as the “baby hearts” debacle and revelations about the retention of human brains in neuropathology laboratories worldwide. Respect for patient’s rights seems, however, to impede research and development of clinical knowledge in contemporary health care. The Common clinical endeavour argument and a Presumption for beneficial use argument suggest that the use of tissues for research and teaching in contemporary health care can respect patients and their values in multicultural communities where there are provisions for oversight and for opting not to contribute, both of which should respect the diverse views of different ethnic or cultural groups.

小鼠MKP4基因组织、细胞表达谱研究

为了探讨MKP4基因mRNA在正常雄性C57小鼠的组织表达分布及其在3T3-L1脂肪细胞诱导进程中的表达谱。采用经典诱导分化方案诱导3T3-L1前脂肪细胞,分别收集前脂肪细胞、诱导分化day0、day2、day5、day8和day9的细胞,同时取正常C57雄性小鼠(鼠龄12周,数量n=3)多处组织如心、胰、肝、脂肪、脑、肾及睾丸等,并提取组织、细胞总RNA,RT-QPCR(荧光染料法)检测MKP4基因mRNA表达水平。结果显示MKP4基因在C57小鼠体内存在较广的表达谱,在肝脏、脂肪的表达量最高,其次为脑组织,其它组织存在低度表达;在3T3-L1前脂肪细胞、诱导分化day0、day2中表达极低,在day5中表达骤然升高,随后表达相对增高,于day9表达水平趋于平稳。MKP4基因组织表达谱结果表明其在维持正常生理功能可能发挥一定的作用,在胰岛素敏感相关组织肝脏、脂肪中表达量较高,提示可能参与胰岛素抵抗(IR)的发生与发展过程。此外,MKP4在3T3-L1前脂肪细胞诱导进程中表达上调,表明MKP4可能参与了脂质积累、肥胖等代谢疾病的发生与发展。     

Bacteriological Survey of Fresh Pork Sausage Produced at Establishments Under Federal Inspection

At the time of manufacture, 75% of 67 sets of finished fresh pork sausage collected in 44 plants had aerobic plate counts in the range of 500,000 or fewer/g; 88% contained 100 or fewer E. coli/g; and 75% contained 100 or fewer S. aureus/g (geometric means of 10 samples). Salmonellae were isolated from 28% of 529 samples of pork trimmings used for sausage, and from 28% of 560 finished sausage samples. Semiquantitative analysis revealed that salmonellae were at low levels; more than 80% of the salmonellae-positive samples were positive only in 25-g portions (negative in 1.0- and 0.1-g portions).     

Tissue inhibitor of metalloproteinase-4 instigates apoptosis in transformed cardiac fibroblasts

Tumor cells become malignant, in part, because of their activation of matrix metalloproteinases (MMPs) and inactivation of tissue inhibitor of metalloproteinases (TIMPs). Myocardial tumors are rarely malignant. This raises the possibility that the MMPs and TIMPs are differentially regulated in the heart compared to other tissues. Therefore, we hypothesized that a tissue specific tumor suppressor exists in the heart. To test this hypothesis we prepared cardiac tissue extracts from normal (n = 4), ischemic cardiomypathic (ICM) [n = 5], and dilated cardiomyopathic (DCM) [n = 8] human heart end-stage explants. The level of cardiospecific TIMP-4 was determined by SDS-PAGE and Western-blot analysis. The results suggested reduced levels of TIMP-4 in ICM and DCM as compared to normal heart. TIMP-4 was purified by reverse phase HPLC and gelatin-sepharose affinity chromatography. Collagenase inhibitory activity of chromatographic peaks was determined using fluorescein-conjugated collagen as substrate and fluorescence spectroscopy. The activity of TIMP-4 (27 kDa) was characterized by reverse zymography. The role of TIMP-4 in cardiac fibroblast cell migration was examined using Boyden chamber analysis. The results suggested that TIMP-4 inhibited cardiac fibroblast cells migration and collagen gel invasion. To test whether TIMP-4 induces apoptosis, we cultured cardiac normal and polyomavirus transformed fibroblast cells in the presence and absence of TIMP-4. The number of cells were measured and DNA laddering was determined. The results suggested that TIMP-4 controlled normal cardiac fibroblast transformation and induced apoptosis in transformed cells. Cardiospecific TIMP-4 plays a significant role in regulating the normal cell phenotype. The reduced levels of TIMP-4 elicit cellular transformation and may lead to adverse extracellular matrix degradation (remodeling), cardiac hypertrophy and failure. This study suggests a possible protective role of TIMP-4 in other organs which are susceptible to malignancy.     

Cutting Edge: Lymphoid Tissue Inducer Cells Maintain Memory CD4 T Cells within Secondary Lymphoid Tissue

Phylogeny shows that CD4 T cell memory and lymph nodes coevolved in placental mammals. In ontogeny, retinoic acid orphan receptor (ROR)γ-dependent lymphoid tissue inducer (LTi) cells program the development of mammalian lymph nodes. In this study, we show that although primary CD4 T cell expansion is normal in RORγ-deficient mice, the persistence of memory CD4 T cells is RORγ-dependent. Furthermore, using bone marrow chimeric mice we demonstrate that LTi cells are the key RORγ-expressing cell type sufficient for memory CD4 T cell survival in the absence of persistent Ag. This effect was specific for CD4 T cells, as memory CD8 T cells survived equally well in the presence or absence of LTi cells. These data demonstrate a novel role for LTi cells, archetypal members of the innate lymphoid cell family, in supporting memory CD4 T cell survival in vivo.     

Tissue Inhibitor of Metalloproteinase-4 Triggers Apoptosis in Cervical Cancer Cells

Tissue inhibitor of metalloproteinase-4 (TIMP-4) is a member of extracellular matrix (ECM) metalloproteinases inhibitors that has pleiotropic functions. However, TIMP-4 roles in carcinogenesis are not well understood. Cell viability and flow cytometer assays were employed to evaluate cell death differences between H-Vector and H-TIMP-4 cell lines. Immunobloting and semi-quantitative RT-PCR were used to evaluate the expression of apoptosis regulators. We showed that TIMP-4 has apoptosis-sensitizing effects towards several death stimuli. Consistent with these findings, regulators of apoptosis from Inhibitors of Apoptosis Proteins (IAP), FLICE-like inhibitor proteins (FLIP) and Bcl-2 family members were modulated by TIMP-4. In addition, TIMP-4 knockdown resulted in cell survival increase after serum deprivation, as assessed by clonogenic cell analyses. This report shows that TIMP-4 regulates carcinogenesis through apoptosis activation in cervical cancer cells. Understanding TIMP-4 effects in tumorigenesis may provide clues for future therapies.     

Cbx4 Sumoylates Prdm16 to Regulate Adipose Tissue Thermogenesis

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Association between Activity Space Exposure to Food Establishments and Individual Risk of Overweight

Objective

Environmental exposure to food sources may underpin area level differences in individual risk for overweight. Place of residence is generally used to assess neighbourhood exposure. Yet, because people are mobile, multiple exposures should be accounted for to assess the relation between food environments and overweight. Unfortunately, mobility data is often missing from health surveys. We hereby test the feasibility of linking travel survey data with food listings to derive food store exposure predictors of overweight among health survey participants.

Methods

Food environment exposure measures accounting for non-residential activity places (activity spaces) were computed and modelled in Montreal and Quebec City, Canada, using travel surveys and food store listings. Models were then used to predict activity space food exposures for 5,578 participants of the Canadian Community Health Survey. These food exposure estimates, accounting for daily mobility, were used to model self-reported overweight in a multilevel framework. Median Odd Ratios were used to assess the proportion of between-neighborhood variance explained by such food exposure predictors.

Results

Estimates of food environment exposure accounting for both residential and non-residential destinations were significantly and more strongly associated with overweight than residential-only measures of exposure for men. For women, residential exposures were more strongly associated with overweight than non-residential exposures. In Montreal, adjusted models showed men in the highest quartile of exposure to food stores were at lesser risk of being overweight considering exposure to restaurants (OR = 0.36 [0.21–0.62]), fast food outlets (0.48 [0.30–0.79]), or corner stores (0.52 [0.35–0.78]). Conversely, men experiencing the highest proportion of restaurants being fast-food outlets were at higher risk of being overweight (2.07 [1.25–3.42]). Women experiencing higher residential exposures were at lower risk of overweight.

Conclusion

Using residential neighbourhood food exposure measures may underestimate true exposure and observed associations. Using mobility data offers potential for deriving activity space exposure estimates in epidemiological models.     

Bacteriological Survey of Frozen Meat and Gravy Produced at Establishments Under Federal Inspection

During visits to 34 federally inspected establishments producing frozen meat and gravy, 541 production line samples and 535 finished product units were collected for bacteriological analyses. It was found that more than 70% of the sets of finished product (10 units/set) produced under good manufacturing practices had: (i) four or fewer coliform-positive units, (ii) two or fewer Escherichia coli-positive units, (iii) three or fewer Staphylococcus aureus-positive units, and (iv) an aerobic plate count of fewer than 50,000/g (geometric mean of 10 units). All finished product units were negative for salmonellae.