Defining the resistance to oxygen transfer in tissue hypoxia

Studies of O2 supply in freshly isolated adult mammalian cells provide new insight into the factors that limit mitochondrial oxygenation in vivo. Of particular importance, mitochondria are present at high densities and often in apparent clusters, both of which contribute to local O2 gradients under hypoxic conditions. Current evidence indicates that the mitochondrial distribution is a component of the differentiated phenotype of adult mammalian cells and that specific motors and anchoring mechanisms are present to allow redistribution in response to developmental, physiological and pathological challenges. To compare the importance of resistance to O2 transfer under different conditions and at different sites along the supply path in vivo, a simple mathematical expression of relative resistance to O2 supply is introduced. Under various pathophysiological conditions, this resistance increases in specific regions of the pulmonary, circulatory or cellular supply path and results in O2 deficiency in the mitochondria. Regardless of cause, the relative resistance increases dramatically in the vicinity of mitochondrial clusters during hypoxia.     

Localization of dystrophin to postsynaptic regions of central nervous system cortical neurons

Moderate non-progressive cognitive impairment is a consistent feature of Duchenne muscular dystrophy (DMD), although no central nervous system (CNS) abnormality has been identified. Recent studies have elucidated the molecular defect in DMD, including the absence of the protein dystrophin in affected individuals. Normal brain tissue contains dystrophin messenger RNA and dystrophin is present in low abundance in the brain and seems to be regulated in this tissue, at least in part, by a promoter that differs from that in muscle. Until now, antibodies and immunocytochemical methods used to demonstrate dystrophin at the plasma membrane of mouse and human muscle have proven inadequate to localize precisely dystrophin in the mammalian CNS. We have now made an antibody (anti 6-10) which is much more sensitive than those previously available to immunolabel dystrophin in the CNS. Using this antibody, we found that in the mouse, dystrophin is particularly abundant in the neurons of the cerebral and cerebellar cortices, and that it is localized at postsynaptic membrane specializations. Dystrophin may have a different role in neurons than in muscle, and an alteration at the synaptic level may be the basis of the cognitive impairment in DMD.     

Performance of an activated carbon made from waste palm shell in simultaneous adsorption of SO_x and NO_x of flue gas at low temperature

This study examined the individual and simultaneous adsorption of SOx(SO2)and NOx(NO-NO2)on activated carbon prepared from waste palm shell.The adsorption process was examined in a fixed bed reactor at low temperatures(100 300°C).For individual adsorption without any catalytic activation,SOx showed good adsorption whereas NOx was very much poor.In the simultaneous adsorption of SOx and NOx,SOx showed greater adsorption affinity than NOx.For palm shell activated carbon(PSAC)impregnated with metal catalyst(Ni and Ce)the concentration adsorbed profile showed that the amount of SOx adsorbed decreased regularly,while the amount of the adsorbed NOx increased irregularly.The properties of the pure and impregnated PSAC were analyzed by BET,SEM and EDX.These investigations indicated that PSAC impregnated with metal catalyst is the determining factor in the adsorption of SOx and NOx simultaneously.     

Electrical and band-gap properties of amorphous zinc-indium-tin oxide thin films

Zinc-indium-tin oxide (ZITO) films were grown by pulsed-laser deposition.Three different material compositions were investigated:ZITO-30,ZITO-50 and ZITO-70 in which 30％,50％ and 70％,respectively,of the...     

Plant and soil relationships in two hydrothermally altered areas of the Breat Basin

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} In two areas of hydrothermally altered rocks in the Great Basin, the native vegetation differs in composition and areal cover from unaltered to altered sites on the same geologic formations. Analysis suggests that physical rather than chemical factors may be the cause of the vegetation differences, especially permeability of bedrock, depth and texture of soils, and, possibly, amounts and types of clay minerals present. These characteristics influence the ability of soils to absorb and retain water. In the East Tintic Mountains, Utah, the soils from argillized or mixed argillized and silicified parent materials have more characteristics associated with dryness and support sparser vegetation and more species especially adapted to dry conditions than do soils from unaltered or silicified parent materials. In Battle Mountain, Nevada, unaltered areas have greater vegetation cover and have soil depth and texture that are more favorable for plants than do altered areas. Soil pH is higher in altered areas than in unaltered areas.     

Change in taste preference related to aging of taste cells in rat

Following the suppression of renewal of rat taste cells by vinblastine sulphate, the preference for sucrose decreased markedly while the aversion to quinine did not change. The results suggest that the sensitivity of taste cells to sucrose decreases with their aging, but the sensitivity to quinine increases.     

Study of the characteristics of the inotropic effect of insulin in rabbit papillary muscle.

The effect of insulin was examined with emphasis on the alteration in the force-frequency relation. The results show that insulin does not change the time to peak tension nor the time of contraction. The inotropic effect was significant and did not depend upon the frequency of stimulation. However, there was a definite dependence of the magnitude of the inotropic effect on temperature. Previous studies have indicated that the inotropic effect is not a result of increased substrate availability or changes in cAMP phosphodiesterase activity. These results and those reported here are consistant with the hypothesis that insulin's inotropic effect is due to increases in intracellular Ca++.     

Upper intestinal lipids regulate energy and glucose homeostasis

Upon the entry of nutrients into the small intestine, nutrient sensing mechanisms are activated to allow the body to adapt appropriately to the incoming nutrients. To date, mounting evidence points to the existence of an upper intestinal lipid-induced gut–brain neuronal axis to regulate energy homeostasis. Moreover, a recent discovery has also revealed an upper intestinal lipid-induced gut–brain–liver neuronal axis involved in the regulation of glucose homeostasis. In this mini-review, we will focus on the mechanisms underlying the activation of these respective neuronal axes by upper intestinal lipids.