Advances in Alzheimer's disease

The problem of the etiology of Alzheimer's disease has not been solved. But in the past several years there have been significant extensions of our knowledge of the disease and advances in determining the molecular changes underlying the disorder. There is now convincing evidence that the dementia per se is caused by loss of neurons and synapses, particularly in neocortex and hippocampus. The molecular aspects of amyloid and its precursor protein have been defined. The nature of intracellular changes leading to accumulation of the paired helical filament is beginning to be understood. For the first time, putative risk factors can be described in terms of pathogenetic mechanisms. Thus, it may become possible in the not-too-distant future to discover interventions that will slow the progress of this devastating disease.     

NEURONAL PIGMENTS: SPECTROSCOPIC CHARACTERIZATION OF HUMAN BRAIN MELANIN

Abstract— A method has been established for the characterization of synthetic melanins obtained from dopamine, norepinephrine, and structurally related compounds which permits the identification of the precursor substrate of the melanin. This is done by interpreting the absorption spectra and the first derivative curves of these melanins solubilized in sodium borohydride. Using this method, the melanin pigment obtained from the substantia nigra of human brain has been shown to be very similar to dopamine-melanin and not DOPA- or norepinephrine-melanins.     

ON ARABINOSE AS A CONSTITUENT OF HYALURONIC ACID FROM BOVINE BRAIN

(1) Wardi , Allen , Turner and Stary (1966) and Margolis (1967) have reported that arabinose is a component of hyaluronic acid from mammalian brain. (2) In the present study, total acidic polysaccharide and hyaluronic acid fractions were isolated from lipid-extracted and proteolysed bovine brain by precipitation with cetyltri-methylammonium bromide. These fractions were analysed for arabinose by paper chromatography of deionized hydrolysates and by gas-liquid chromatography of per(trimethylsilyl)ated methanolysates. (3) Two pentoses, xylose and ribose, were detected. Arabinose was analytically undetectable in both polysaccharide fractions, but was easily detected in a control polysaccharide containing 0-1% (w/w) arabinose. Arabinose, if present in hyaluronic acid from bovine brain, constitutes less than 0.1 mol per mol of hyaluronic acid (molecular weight 1.5 x 10⁶ daltons).