Homocysteine and cognitive function in geriatric depression.

BACKGROUND/OBJECTIVES: Cognitive dysfunction is a common aspect of the spectrum of symptoms of geriatric depression. High homocysteine levels have been linked to cognitive decline in neuropsychiatric disorders. The present study investigated possible associations between cognitive impairment observed in geriatric depression and homocysteine levels. METHODS: The performance of 25 mentally healthy individuals and 40 patients with geriatric depression in terms of language processing, processing speed, concentration and attention was assessed with the Stroop Test and the d2 Test of Attention. Serum homocysteine was determined with an enzyme immunoassay. RESULTS: The performance of depressed patients was significantly worse in language processing (p = 0.001) and processing speed (p < 0.0001). Depressed patients with high levels of homocysteine performed better than patients with homocysteine concentrations

Molecular cloning and characterization of a gene encoding a 13.1 kDa antigenic protein of Naegleria fowleri.

An antigen-related gene was cloned from a cDNA expression library of Naegleria fowleri by immunoscreening with sera obtained from mice that were either immunized with an amoebic lysate or infected with trophozoites. The coding nucleotide sequence of the cloned gene consisted of 357 bases that were translated into 119 amino acids. This gene was designated as nfa1. The predicted amino acid sequence of Nfa1 protein has two potential glycosylation and three potential phosphorylation sites, and its predicted secondary structure consists of four helices and three corners. The deduced amino acid sequence of Nfa1 protein shares 43% identity with the myohemerythrin (myoHr) protein from a marine annelid, Nereis diversicolor, including 100% identity in conserved regions and iron-binding residues. A phylogenetic tree constructed from amino acid sequences placed the N. fowleri Nfa1 protein outside of a cluster of myoHr proteins from eight invertebrates. A purified recombinant protein that migrated as a 13.1 kDa species in SDS-PAGE was produced. This recombinant protein exhibited a strong immunoreactivity with infected, immune, and anti-Nfal sera. In addition, an anti-Nfa1 serum reacted with an amoeba lysate in immunoblotting analysis. The present nfal gene encoding the myoHr-like protein is the first myoHr gene cloned from protozoa, and the Nfal antigen may be useful in diagnostic studies