Increased BAEP latency and reduced brain cytochrome c oxidase activity observed in the Suzuki model of Alzheimer's disease [abstract]

Cytochrome c oxidase (COX), the terminal respiratory enzyme, is reported to be deficient and to exhibit reduced activity in a number of neurodegenerative disorders. The Alzheimer's rabbit model is based on the intracerebral injection of Holt's adjuvant, an aluminum salt solution. This model was used to compare the brain activity and the activity of brain COX in treated and controlled rabbits. Of a total of 26 New Zealand white rabbits, thirteen were injected intracerebrally with Holt's adjuvant solution, five with physiologically saline solution and the remainder were kept as controls. The auditory responses (BAEP) of the rabbits were monitored for 14 days before injections and 14 days thereafter. The animals were then sacrificed and brain mitochondrial extracts were used for SDS-PAGE analysis, difference spectra spectrophotometry and polarographic assays. The results of SDS-PAGE showed that there were no differences in the protein composition of the brain mitochondria of the three groups. Similarly, difference spectra (reduced minus oxidized, 400-630 nm) from both treated groups were identical to that of the control with characteristic maxima centered around 434, 550 and 604 nm. Polarographic assays, however, showed that while the enzyme from both treated groups displayed the characteristic biphasic kinetics, there was reduced activity in the enzymes from the brain of rabbits receiving the adjuvant but not the saline solution. This result is significant in light of the fact that several researchers have reported reduced activity of COX from Alzheimer's disease (AD) patients. Of particular significance, BAEP results reveal an increase in the interpeak latency between peaks III and V of the Holt's injected but not the saline injected or control rabbits. This latter result suggests that monitoring the BAEP might provide a simple non-invasive method for confirming AD. (AU)

Antigenic variability in trichuris trichiura populations

The present study examines antigenic variability for the human whipworm Trichuris trichiura. Recognition by IgG of somatic antigens of individual worms collected from 3 intensely infected children from Jamaica, West Indies has been investigated by immunoblotting. When probed with 1 plasma sample, significant differences in recognition of 2 selected antigens among worm populations and between male and female worms was observed. In addition, there was evidence for antigenic variability within worm populations at the individual worm level. Such variations may have considerable implications for the development of immunity to parasitic nematodes.(AU)

Duplication of the Ace.1 locus in Culex pipiens mosquito from the Caribbean

In Culex pipiens mosquitoes, AChE1 encoded by the locus Ace.1 is the target of organophosphorous and carbamate insecticides. In several resistant strains hompzygous for Ace.1RR, insensitive AChE1 is exclusively found. An unusual situation occurs in two Caribbean resistant strains where each mosquito, at each generation, displays a mixture of sensitive and insensitive AChE1. These mosquitoes are not heterozygotes, Ace.1RS, as preimaginal mortalities cannot account for the lethality of both homozygous classes. This situation is best explained by the existence of two Ace.1 loci, coding, respectively, a sensitive and insensitive AChE1. Thus, we suggest that in the Caribbean a duplication of the Ace.1 locus occurred before the appearance of insecticide resistance at one of the two copies.(AU)

Strongyloides stercoralis: characterization of immunodiagnostic larval antigens

Forty-one-, 31-, and 28-kDa proteins of strongyloides stercoralis filariform larvae have previously been demonstrated to be sensitively and specifically recognized by serum IgG in individuals with strongyloidiasis. Characteristics of these proteins, their immunodominant epitopes, and reactive antibodies are described here. The proteins are soluble is aqueous as well as detergent extracts. The immunodominant epitopes are present in S. stercoralis but not in S. cebus or S. ratti. Epitopes on the three proteins are not shared, as determined by cross-absorption of serum with each of the size components on nitrocellulose. In most sera from strongyloidiasis patients there was reactivity to each of the proteins by IgG1 and IgG4, but reactivity by IgG2 or IgG3 was detectable only in a minority. A rabbit antiserum raised to a 41-kDa size fraction of S. stercoralis larvae reacted against a doublet of 41-kDa which was distinct from the immunodiagnostic 41-kDa protein.(AU)

Auxotypes, plasmid contents, and serovars of gonococcal strains (PPNG and non-PPNG) from Jamaica.

The analysis of the auxotypes and plasmid profiles of 459 non-PPNG strains from Jamaica suggest that strains have been imported to the island. Unlike in many developing countries where strains are differentiated by only a few auxotypes, 13 different auxotypes were identified in the non-PPNG strains. In Jamaica over 10 percent of the strains were plasmid free and required proline, citrulline, and uracil (PCU-)for growth. These isolates predominate in Canada and are increasingly reported from areas of the United States of America and Europe. The serological analysis of 168 of the non-PPNG strains indicated that most (76 percent, 128) were from serogroup WII/III. Serogroup WII/III strains comprised 17 serovar combinations with GS and PH reagents, whereas serogroup WI strains included only four serovars. Unusually, most WI Aedgkih non-PPNG strains were wild type or proline requiring. Strains of serovar Aedg were especially noted (in 93 percent, 13/14) for carriage of the transfer plasmid. The first 20 PPNG strains isolated in Jamaica proved to have multiple origins as they had eight variations of auxotype, serovar, and plasmid content. Most (60 percent, 12/20) of those isolated were typed as serogroup WI, and 10 of these isolated were serovar Aedfkih. Although most (70 percent, 14/20) PPNG strains harboured African type plasmids with or without transfer plasmids, six also carried Asian type plasmids (with the transfer plasmid).(AU)

Haemoglobin Spanish Town alpha27 Glu replaced by Val (B8)

A new alpha chain variant Hb Spanish Town, a27 Glutamic acid-Valine, awas detected in the cord blood of a Jamaica Negro infant. In the mother the adult component (a2 Spanish TownB2) has an electrophoretic mobility between haemoglobins S and F at alkaline pH and measures 11.0-12.0 percent of the total haemoglobin. (Summary)