Cystine crystalls

There are numerous abnormalities of cysteine metabolism. Cystine, lysine, arginine, and ornithine are excreted in cystine-lysinuria (cystinuria), a defect in renal reabsorption. Apart from cystine calculi, cystinuria is benign. The mixed disulfide of L-cysteine and L-homocysteine (Figure 30-9) excreted by cystinuric patients is more soluble than cystine and reduces formation of cystine calculi. Several metabolic defects result in vitamin Bg-responsive or -unresponsive ho-mocystinurias. Defective carrier-mediated transport of cystine results in cystinosis (cystine storage disease) with deposition of cystine crystals in tissues and early mortality from acute renal failure. Despite... 

Excretion of cystine in abnormal amounts can occur in many other cases for instance in cystinosis, the characteristic feature of which is the deposit of cystine crystals in the body tissues, although cystinosis is not always accompanied by excessive excretion of cystine alone in the urine. In de Toni-Debre-Fanconi syndrome there is also an increased cystine output, but this is part of a generalized hyperamino aciduria such as... 

Decomp 260-261°. d-Cystine Crystals. Sidy sol in water. dl-Cystine, the synthetic racemic form Crystals. Sltly sol in water. meso-Cystine, the internally compensated form Crystals. Sltly sol in water. 

Autosomal recessive cystinosis is caused by an enzyme-induced blockage of cystine degradation, particularly in the RES lysosomes of the bone marrow, liver, spleen and kidneys. Especially in the stellate cells of the spleen and to a lesser extent of the hepatic lobule centres, hexagonal and rectangular cystine crystals are found, pointing at an early stage to cystinosis. There is evidence of hepatosplenomegaly and microvesicular steatosis. The clinical picture of the infantile type presents as a Fan-coni syndrome, (s. pp 593, 597) The children affected die in the first five years of life. 

Tsilou ET, Thompson D, Lindblad AS, Reed GF, Rubin B, Gahl W, Thoene J, Del Monte M, Schneider JA, Granet DB, Kaiser-Kupfer MI. A multicentre randomised double masked clinical trial of a new formulation of topical cysteamine for the treatment of corneal cystine crystals in cystinosis. Br J Ophthalmol 2003 87(1) 28-31. 

Cystinuria la. Type I (kidney 4- gut) lb. Type II (kidney -f gut) lc. Type III (kidney 4" gut) (reoesBive ) Cystine 4 dibasic amino acids Cystine + dibasic amino acids Cystine 4- dibasic anuno adds Cystine and dibasic amino acids 1 Dibasic amino acids / Normal absorption 1 Renal calculi usually containing cystine (treatment with high water intake or penicillamine administration) Chromato phy, cystine crystals in urine urinary nitro-prusside test is podtive (B6, E5, H17, H18, K12, M8. P12, H6, R8, T3a)... 

Cystinuria is a disorder of renal and gastrointestinal tract amino acid transport that also affects lysine, ornithine, and arginine. The four amino acids share a common transport mechanism (discussed above). Clinically, it presents as urinary stone disease because of the insolubility of cystine. In cystinosis, cystine crystals are deposited in tissues because of a transport defect in ATP-dependent cystine efflux from lysosomes (discussed above). 

Cystinosis This is a lysosomal storage disorder where there is a defect in the membrane transport of cystine. Cystine crystals are deposited in kidney, liver, spleen, bone marrow and cornea... 

DL-Form. crystals. Soly in water at 25° 0.057 g/1. meso-Cystine, crystals. Soly in water 0,056 g/1. therap cat Adjuvant in treatment of alopecia, seborrhea, brittleness of nails. 

Two human genetic diseases are known which involve this disulphide amino acid. In one, cystinuria , there is a transport defect in the intestine and kidney. This results in abnormally high levels of cystine in the urine and can result in the precipitation of cystine crystals and kidney stone formation. In cystinosis, cystine crystals form within cells and eventually cause severe kidney damage. The nature of the primary biochemical lesion is unknown all known cystine reduction systems of the cell appear to be normal. 

Accumulation of cystine crystals in RE cells, amorphous cystinuria, cystine accumulation in fibroblasts, leukocytes, and mucosa cells... 

Preparation by acidic proteine hydrolysis (e. g. of keratines) with following fractionated crystallization (obtained in commonly with i.-cystine). 

Clausen T, Kaiser JT, Steegborn C, et al. 2000. Crystal structure of the cystine C-S lyase from Synechocystis stalibization of cysteine persulfide for FeS cluster biosynthesis. Proc Natl Acad Sci USA 97 3856-61. 

The mixture is filtered hot and the insoluble residue is washed with distilled water. The total filtrate is now partially neutralized with 300 cc. of 40 per cent sodium hydroxide solution, while the mixture is well stirred and cooled, and then a saturated solution of 3750 g. of crystallized sodium acetate is added. The Congo Red test for mineral acid should then be entirely negative. Care must be taken not to make the solution alkaline with sodium hydroxide (Note 7). After standing for three days at room temperature, the precipitated cystine is filtered on a suction iunnel. This crude material, containing in addition to the... 

If the mixture is allowed to stand for a longer time, tyrosine tends to crystallize out with the cystine. 

The condition develops progressively and becomes detectable only after several months (B20). That tyrosine crystals are also deposited as well as cystine was not confirmed (Bl, F19). 

In Eq. (10), E nt s(u) and Es(in) are the s=x,y,z components of the internal electric field and the field in the dielectric, respectively, and p u is the Boltzmann density matrix for the set of initial states m. The parameter tmn is a measure of the line-width. While small molecules, N<pure solid show well-defined lattice-vibrational spectra, arising from intermolecular vibrations in the crystal, overlap among the vastly larger number of normal modes for large, polymeric systems, produces broad bands, even in the crystalline state. When the polymeric molecule experiences the molecular interactions operative in aqueous solution, a second feature further broadens the vibrational bands, since the line-width parameters, xmn, Eq. (10), reflect the increased molecular collisional effects in solution, as compared to those in the solid. These general considerations are borne out by experiment. The low-frequency Raman spectrum of the amino acid cystine (94) shows a line at 8.7 cm- -, in the crystalline solid, with a half-width of several cm-- -. In contrast, a careful study of the low frequency Raman spectra of lysozyme (92) shows a broad band (half-width 10 cm- -) at 25 cm- -,... 

L-Cystine occurs as colorless to white crystals. It is soluble in diluted mineral acids and in alkaline solutions. It is very slightly soluble in water and in alcohol. 

BMP-2 has in common with BMP-7 and other members of the TGF-P family, a structural scaffold, consisting of a cystine-knot motif and two finger-like double-stranded P-sheets which determine the mode of dimerization. Secondary-structure differences between BMP-2 and BMP-7 account for the recognition and specific interaction with different binding partners. The crystal structure of human bone morphogenetic protein-2 is shown in Fig. 6.2. 

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