Cortex composition

Wool fibers have a very complex morphological stmcture. They can be considered as biological composite materials, in which the various regions are both chemically and physically different (87). Fine wool fibers contain two types of cell those of the internal cortex and those of the external cuticle. 

Poly-L-lysine-blended chitosan, collagen-blended chitosan and albumin-blended chitosan were also considered, with collagen control material. Culture of PC12 cells and fetal mouse cerebral cortex cells on these biomaterials was used to evaluate their nerve cell affinity. The composite materials, had significantly improved nerve cell affinity compared to chitosan. Poly-L-lysine-blended chitosan exhibited the best nerve cell affinity and was a better material in promoting neurite outgrowth than collagen [328]. 

The essential genetic material ofthe original vegetative bacterium is retained in the core or protoplast around this lies the thick cortex which contains the murein or peptidoglycan already encountered as a cell wall component (see Fig. 1.2). The outer coats which are protein in composition are distinguished by their high cysteine content. In this respect they resemble keratin, the protein of hair and horn. 

The cerebral cortex is conventionally subdivided into four main regions that may be delineated by the sulci, or large clefts, termed the frontal, temporal, parietal and occipital lobes. These names are derived from the bones of the skull which overlay them. Each lobe may be further subdivided according to its cellular structure and composition. Thus Brodmarm has divided the cortex into approximately 50 discrete areas according to the specific cellular structure and function. For example, electrical stimulation of the strip of cerebral cortex in front of the central sulcus (see Figure 1.3) is responsible for motor commands to the muscles. This is termed the primary motor cortex and can be further subdivided according to which muscles are controlled in different parts of the body. 

Further results from these Raman studies showed that the lens nucleus and cortex had somewhat different amino acid compositions. It could be concluded that the nuclear portion has highest concentration of y-crystallin, and that the content of a-crystallin increases significantly from the nucleus to the cortex. Furthermore, it was found that sulfhydryl groups and (i-conformation are unaffected in the conversion from a transparent to totally opaque lens by heat denaturation. This indicates that the opacification of the lens does not necessarily involve the oxidation of sulfhydryl groups or conformational changes [3],... 

Fig. 56 Representative composite micrographs of BrdU immunostaining spanning all neo-cortical layers of the frontal cortex of control and postischemic day-9 monkeys. The position of the visual field is depicted as a frame on the schematic map (upper right). Note the increased number of positive cells after ischemia. F, frontal cortex S, striatum. Scale bar = 200 pm...

Two vanadium bromoperoxidases that differ in carbohydrate content [26,33] have been isolated from A. nodosum. The most abundant bromoperoxidase, V-BrPO-I, was found in the thallus, and the other bromoperoxidase, V-BrPO-II, was reported to be present on the thallus surface [26], A previous report also concluded that V-BrPO is present in two different locations of A. nodosum, one in the cell walls of the transitional region between the cortex and medulla of the thallus and the other in the cell wall of the thallus surface [34], More recent experiments demonstrate that vanadium-dependent bromoperoxidase activity is present in both the cortical and surface protoplasts of M. pyrifera [35], L. saccharina, and L. digitata [36], The biosynthesis of V-BrPO in the protoplasts of L. saccharina has been shown using [35S]-methionine [36], The vanadium bromoperoxidases are all acidic proteins [26] with very similar amino acid compositions [37], V-BrPO (A. nodosum) has been crystallized, although refined structural data have not been reported yet [38], A different isolation procedure, based primarily on a two-phase extraction system, has been described [39,40], This procedure works well for certain types of algae (e.g., Laminaria) but not for the isolation of V-BrPO from A. nodosum, the principal source of V-BrPO for the mechanistic studies. 

Changes in EFA status affect the activity of several membrane-associated enzymes and proteins 68-71 Reduced adenyl cyclase activity occurred in EFA-deficient animals,72 while in animals supplemented with n-6 or n-3 fatty acids, increased adenyl cyclase activity was seen in cardiac membranes.73,74 However, the opposite effect has been reported in other membranes, possibly reflecting differences in initial fatty acid composition.75 n-3 PUFAs have been shown to activate membrane Ca-ATPase and inhibit Na, K-ATPase in isolated basolateral membranes from rat duodenal enterocytes76 and inhibit both Ca-ATPase and Na,K-ATPase activity in synaptosomal membranes isolated from rat cerebral cortex.77 EFAs have the ability to modify neuronal Ca-ATPase activity... 

Compared to bone material, the composition and structure of flint is much simpler. Flint takes part in the big family of silicon-containing sedimentary rocks. It is basically composed of homogeneous microcrystalline silica grains, which give it a homogeneous macroscopic aspect. The name flint especially defines rocks where the cortex is thin and the heart of the stone is characterised by the absence of calcite. The majority of flint is found dispersed in sediments or as subcontinuous... 

PHIONITA — Natural Hostility or Antipathy, such as one animal or composite of any kind entertains towards another, as for example, the antipathy of the cat for the mouse, of one pole of the magnet for the other. The Philosophers say that their Dragon has this quality in respect of water, and that it must be forced to drink thereof, and to bathe therein, so that it may be relieved of its old skin or impure cortex. 

The composition of the excreted urinary 17-ketosleroids also reveals a close similarity between the hormones of different origin the testis accounts for 30% while the adrenal cortex contributes the remaining 70% of the total urinary 17-ketosteroids [383]. Androsterone, ep a-androsterone, and 5/8-androsterone (etiocholanolone) are the main urinary metabolities of testosterone, and dehydroepiandrosterone is the major urinary 17-ketosteroid derived from the adrenal cortex. 

After intravenous treatment of rats with 1200 mg/kg/d CPH for 3 days, homogenates of the renal cortex were separated into subcellular fractions and their protein composition analyzed. The results of the SDS-gel electrophoresis of the renal cortical subtractions showed significant alterations of the polypeptide pattern in the microsomal fraction. The analysis of the polypeptide composition of the microsomal fraction indicated that paralleling to the depletion of cytochrome P-450 isoenzymes in the molecular weight range 50-53,000 was the induction of a polypeptide of molecular weight 44,000 [74]. 

Each kidney is subdivided anatomically into three zones (1) an outer zone called the cortex, (2) an intermediate zone called the medulla, and (3) an innermost zone called the pelvis. The cortex and medulla have important characteristics that help facilitate the formation of urine and control the composition of waste products, electrolytes, and water. 

The mineralocorticoids have a main action on the distal tubules in the kidney to increase sodium absorption, with concomitant increased excretion of K and H. Aldosterone is the main endogenous mineralocorticoid. It is produced in the outermost layer of the adrenal cortex (the zona glomerulosa). An excessive secretion of mineralocorticoids (e.g. in Conn s syndrome) causes marked salt and water retention, with a resultant increase in the volume of extracellular fluid, alkalosis, hyperkalaemia and often hypertension. A decrease in secretion (e.g. Addison s disease) causes a disproportional loss of Na compared to fluid loss, so osmotic pressure of the extracellular fluid is reduced. This results in an increase in intracellular compared to extracellular fluid volume. The concomitant decrease in excretion of K results in hyperkalaemia with some decrease in bicarbonate. The control of synthesis and release of aldosterone is complex and involves both the renin-angiotensin system and the electrolyte composition of the blood. As with other... 

Bidirectional, experience-depen-dent regulation of N-methyl-D-aspartate receptor subunit composition in the rat visual cortex during postnatal development. Proc. Natl. Acad. Sci. USA 96(22) 12876-80... 

Philpot BD, Sekhar AK, Shouval HZ, Bear MF. 2001. Visual experience and deprivation bidirectionally modify the composition and function of NMDA receptors in visual cortex. Neuron 29(1) 157-69... 

Lu HC, Gonzalez E, Crair MC. 2001. Barrel cortex critical period plasticity is independent of changes in NMDA receptor subunit composition. Neuron 32(4) 619-... 

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