Distribution in brain

Serotonergic neurons contain the enzyme L-tryptophan-5-monooxygenase (EC 1.14.16.4), more commonly termed tryptophan hydroxylase, which converts tryptophan to 5-hydroxytryptophan (5-HTP) (Fig. 13-5). Tryptophan hydroxylase contains 444 amino acids, corresponding to a molecular weight of about 51 Da. This enzyme is synthesized in serotonergic cell bodies of the raphe nuclei and is found only in cells that synthesize 5-HT. Therefore its distribution in brain is similar to that of 5-HT itself. The Km of tryptophan hydroxylase for tryptophan is approximately 30-60 pmol/1, a concentration comparable to that of tryptophan in brain. If the concentration of tryptophan in serotonergic neurons is assumed to be comparable to that in whole brain, the enzyme would not be saturated with substrate, and the formation of 5-HT in brain would be expected to rise as the brain concentration of tryptophan increases. This has been found to occur in response to raising the dietary intake of tryptophan specifically. 

McPhee, I., Pooley, L., Lobban, M., Bolger, G. and Houslay, M. D. Identification, charactirization and regional distribution in brain of RPDE-6 (RNPDE4A5), a novel splice variant of the PDE4A cyclic AMP phosphodiesterase family. Biochem. J. 310 965-974,1995. 

A few studies have been conducted on cannabis and its derivatives. Alozie et al. (3) measured the radioactivity accumulated in various brain areas following the intravenous injection of 3H-THC, 3H-cannabinol, and 3H-cannabidiol to adult male rats. Five minutes after injection, these three labeled compounds exhibited a homogeneous distribution in brain, suggesting that no specific binding occurred. Such studies must be completed by examining the time course of the evolution of 3H-cannabis derivatives in various brain areas before any firm conclusion can be drawn. 

Transmitter Distribution in brain Physiological Involvement in CNS disease... 

Cataldo AM, Paskevich PA, Kominami E, et al Lysosomal hydrolases of different classes are abnormally distributed in brains of patients with Alzheimer s disease. Proc Natl Acad Sci U S A 88 10998-11002, 1991... 

Peyton JC, Borowitz JL. 1978. Effects of Ba and Ccf on convulsive electroshock sensitivity and Ca distribution in brain subcellular fractions in mice. Toxicol Appl Pharmacol 45 95-103. 

Fig. 16. Al distribution in brain and liver of treated and untreated mice, with and without measures to avoid extraneous Al contamination...

MakCay, A. J., Deen, D. F., and Szoka, F. C., Jr. (2005), Distribution in brain of liposomes after convection enhanced delivery modulation by particle charge, particle diameter, and presence of steric coating, Brain Res., 1035,139-153. 

Cholesterol is a solid alcohol the average human body contains about 200 g distributed in brain, spinal cord, and nerve tissue and occasionally clogging the arteries and the gall bladder (see Chapter 22 for background and procedure for isolating cholesterol from human gallstones). 

Khan A, Jallo GI, Liu YJ, Carson Sr BS, Guarnieri M (2005) Infusion rates and drug distribution in brain tumor models. J Neurosurg (Pediatr 1) 102 53-58. 

Zahlsen et al. (1993) found that C8-C10 hydrocarbons were extremely well absorbed and their tissue distribution in brain and fat were largely dependent on the number of carbon atoms. -Nonane is one component of JP-8 and it is metabolized at relatively high rates to hydroxyl derivatives, which are converted to the corresponding ketone. Other important hydrocarbons (from a... 

Table 11.1 Neurotransmitters, distribution in brain and involvement in CNS disorders...

Jackson, S.N., Wang, H.Y. and Woods, A.S., Direct profiling of lipid distribution in brain tissue using MALDI-TOF MS, Anal Chem, 77 (2005) 4523-4527. 

Iron distribution in brain and its role for oxidative stress... 

Perl, D.P. and Good, P.F. (1992) Comparative techniques for determining cellular iron distribution in brain tissues. Ann. Neurol 32 (Suppl.) 76-81. 

In many situations, drug transport due to bulk flow can be neglected. This assumption (v is zero) is common in previous studies of drug distribution in brain tissue [17]. For example, in a study of cisplatin distribution after continuous infusion into the brain, the effects of bulk flow were found to be small, except within 0.5 mm of the site of Infusion [24]. In the cases considered here, since drug molecules enter the tissue by diffusion from the polymer implant, not by pressure-driven flow of a fluid, no flow should be introduced by the presence of the polymer. With fluid convection assumed to be negligible, the general governing equation in the tissue. Equation 10-17, reduces to ... 

On March 20, 1995, a terrorist attack using sarin occurred on the Tokyo subway. The sarin was mixed in organic solvent and vaporised in the closed compartment of a train. Many people inhaled the sarin gas and collapsed, Eventually, 12 people died and more than 5000 were injured (Suzuki et ah, 1995 Masuda et ai., 1995 Nozaki et ai, 1995). However, neither sarin nor its hydrolysis products were detected in the blood of almost all the sarin victims. It was concluded that sarin pa.ssed through the blood-brain barrier and became distributed in brain ti.ssuc. These facts suggest that various brain... 

C-labeled methionine (MET), -labeled alpha-meth-yltyrosine (IMT), and F-labeled 0-(2-fluoroethyl)-L-tyrosine (FET) are the most important radiolabeled amino acids used in the diagnosis of brain tumors. These three tracers have shown a very similar uptake intensity and distribution in brain tumors (Langen et al. 1997 Weber et al. 2000). Currently available amino acid-PET tracers are accumulated by L and A amino acid transporters. Tumor cells take up radiolabeled amino acids at a high rate, while there is only a relatively low uptake in normal cerebral tissue. At the level of the blood-brain barrier (BBB) they are independent from the BBB disturbance. 

A double-focusing sector field LA-ICP-SFMS (Element, Cetac LSX 200) was employed to measure the ion intensities of two essential elemental (Cu and Zn) and toxic metals (Pb and U) within the tumor area and the surrounding region invaded by CBM as well as in control tissue. The size of the brain samples was approximately 1 cm. The quantitative determination of copper, zinc, lead and uranium distribution in brain tissues by LA-ICP-MS was performed again using prepared matrix-matched laboratory standards doped with these elements of interest. An inhomogeneous... 

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