Effect of Alpha Linolenic Acid Supplementation on Serum Prostate Specific Antigen (PSA): Results from the Alpha Omega Trial

Background

Alpha linolenic acid (ALA) is the major omega-3 fatty acid in the diet. Evidence on health effects of ALA is not conclusive, but some observational studies found an increased risk of prostate cancer with higher intake of ALA. We examined the effect of ALA supplementation on serum concentrations of prostate-specific antigen (PSA), a biomarker for prostate cancer.

Methods

The Alpha Omega Trial (ClinicalTrials.gov Identifier: {"type":"clinical-trial","attrs":{"text":"NCT00127452","term_id":"NCT00127452"}}NCT00127452) was a double-blind, placebo-controlled trial of ALA and the fish fatty acids eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) on the recurrence of cardiovascular disease, using a 2×2 factorial design. Blood was collected at the start and the end of the intervention period. The present analysis included 1622 patients with a history of a myocardial infarction, aged 60–80 years with an initial PSA concentration <4 ng/mL. They received either 2 g per day of ALA or placebo in margarine spreads for 40 months. T-tests and logistic regression were used to assess the effects of ALA supplementation on changes in serum PSA (both continuously and as a dichotomous outcome, cut-off point: >4 ng/mL).

Findings

Mean serum PSA increased by 0.42 ng/mL on placebo (n = 815) and by 0.52 ng/mL on ALA (n = 807), a difference of 0.10 (95% confidence interval: −0.02 to 0.22) ng/mL (P = 0·12). The odds ratio for PSA rising above 4 ng/mL on ALA versus placebo was 1.15 (95% CI: 0.84–1.58).

Interpretation

An additional amount of 2 g of ALA per day increased PSA by 0.10 ng/mL, but the confidence interval ranged from −0.02 to 0.22 ng/mL and included no effect. Therefore, more studies are needed to establish whether or not ALA intake has a clinically significant effect on PSA or prostate cancer.

Trial registration information

ClinicalTrials.gov; Identifier: {"type":"clinical-trial","attrs":{"text":"NCT00127452","term_id":"NCT00127452"}}NCT00127452. URL: http://www.clinicaltrials.gov/ct2/show/{"type":"clinical-trial","attrs":{"text":"NCT00127452","term_id":"NCT00127452"}}NCT00127452.     

Coxiella burnetii Seroprevalence in Small Ruminants in The Gambia

Background

Q fever is a zoonosis caused by Coxiella burnetii, a Gram negative bacterium present worldwide. Small ruminants are considered the main reservoirs for infection of humans. This study aimed to estimate the extent of C. burnetii infection among sheep and goats in part of The Gambia.

Methodology/Principal Findings

This survey was carried out from March to May 2012 at two areas in The Gambia. The first area comprised a cluster of seven rural villages situated 5–15 km west of Farafenni as well as the local abattoir. A second sampling was done at the central abattoir in Abuko (30 km from the capital, Banjul) in the Western Region. Serum samples were obtained from 490 goats and 398 sheep. In addition, 67 milk samples were obtained from lactating dams. Sera were tested with a Q fever ELISA kit. C. burnetii DNA was extracted from milk samples and then detected using a specific quantitative multiplex PCR assay, targeting the IS1111a element. A multivariable mixed logistic regression model was used to examine the relationship between seropositivity and explanatory variables. An overall seroprevalence of 21.6% was found. Goats had a significantly higher seroprevalence than sheep, respectively 24.2% and 18.5%. Seropositive animals were significantly older than seronegative animals. Animals from the villages had a significantly lower seroprevalence than animals from the central abattoir (15.1% versus 29.1%). C. burnetii DNA was detected in 2 out of 67 milk samples, whereas 8 samples gave a doubtful result.

Conclusion/Significance

A substantial C. burnetii seroprevalence in sheep and goats in The Gambia was demonstrated. People living in close proximity to small ruminants are exposed to C. burnetii. Q fever should be considered as a possible cause of acute febrile illness in humans in The Gambia. Future studies should include a simultaneous assessment of veterinary and human serology, and include aetiology of febrile illness in local clinics.     

Characterization of FapR, a positive regulator of expression of the 987P operon in enterotoxigenic Escherichia Coli

Expression of the 987P gene cluster is activated by the adjacent IS1 element of an ST_pa transposon. Nucleotide sequence analysis of the 987P-DNA region contiguous with this IS1 element revealed the presence of an open reading frame designated fapR, encoding a basic protein of 260 amino acid residues with a molecular mass of 30349 Daltons. The gene product, FapR, possesses similarity to a number of positive regulators of gene expression: VirF, Rns, AppY and EnvY. Moreover, a 43-amino-acid residue sequence in the C-terminal part of FapR is similar to the C-terminal domain of AraC, RhaR, and RhaS. Expression of fapR is dependent on the adjacent IS1 element. The FapR protein appears to be required for activation of the silent promoter of the fimbrial subunit gene, fapC     

Report on the international workshop on alternative methods for Leptospira vaccine potency testing: State of the science and the way forward

Routine potency testing of Leptospira vaccines is mostly conducted using a vaccination–challenge test that involves large numbers of hamsters and unrelieved pain and distress. NICEATM, ICCVAM, and their international partners organized a workshop to review the state of the science of alternative methods that might replace, reduce, and refine the use of animals for veterinary Leptospira vaccine potency testing and to identify ways to advance improved alternative methods. Vaccine manufacturers were encouraged to initiate or continue product-specific validation using in vitro enzyme-linked immunosorbent assays as replacements for potency testing of four common Leptospira serogroups. Participants discussed the potential for eliminating the back-titration procedure in the hamster challenge assay, which could reduce animal use by 50% for each individual potency test. Further animal reduction may also be possible by using cryopreserved Leptospira stock to replace continual passaging through hamsters. Serology assays were identified as a way to further reduce and refine animal use but should be considered only after attempting in vitro assays. Workshop participants encouraged consideration of analgesics and use of earlier humane endpoints when the hamster vaccination–challenge potency assay is used. International harmonization of alternative potency methods was recommended to avoid duplicative potency testing to meet regionally different requirements.     

Fumonisin production by field strains of Fusarium nygamai (Gibberella nygamai) and ascospore progeny of laboratory crosses

Field strains of Fusarium nygamai (Gibberella nygamai) are important producers of the fumonisin mycotoxins. Such strains were mated on carrot agar to obtain ascospore progeny. Field strains and ascospore progeny of F. nygamai produced differential levels of fumonisin B1 (FB1) and B2 (FB2) suitable for genetic analyses. Most of the strains produced higher levels of FB1 than FB2. Ascospore progeny from crosses segregated in 1:1 ratios for loci controlling FB1 production and mating type. These findings can be used as the basis to elucidate the genetics of fumonisin production by F. nygamai.     

Mono-association of mice with non-cultivable,intestinal, segmented,filamentous bacteria

A technique is described so that mice mono-associated with non-cultivable, segmented filamentous bacteria (SFB's) can be produced for the first time. As SFB donors, mice were used which had an intestinal microflora consisting of both SFB's and bacteria of the genus Clostridium. Recipients were germ-free mice. It was demonstrated that the intraileal inoculation method was more effective than the orogastric route. Therefore, intestinal homogenates of donor mice were treated with filtered ethanol, diluted and administered intraileally to recipient mice. Evidence is presented that cage mates of the recipient mice were mono-associated with SFB's. The availability of these animals, i.e. in vivo monocultures of SFB's, allows taxonomic and functional characterization of SFB's, which was as yet not possible.Abbreviation SFB Segmented filamentous bacterium     

Organization and expression of genes involved in the biosynthesis of 987P fimbriae

Summary A chromosomal DNA segment encoding the biosynthesis of 987P fimbriae was isolated by cosmid-cloning and subsequent subcloning into pBR322. The 12 kb DNA segment expressed five polypeptides with apparent molecular weights of 81,000, 39,000, 28,500, 20,500, and 16,500, respectively. The location of the corresponding genes was determined by insertional mutagenesis using Tn5. The 20.5 K polypeptide was identified as the 987P fimbrial subunit by its reaction with specific anti-987P antibodies. The 81, 39, and 28.5 K polypeptides appeared to be accessory proteins involved in 987P production.     

Different degree of ileal colonization by segmented, filamentous bacteria in two strains of mice.

Segmented, filamentous bacteria (SFBs) are autochthonous, apathogenic inhabitants of the ileum of various animal species. Outbred Swiss (Cpb:SE) mice have significantly higher degrees of SFB colonization than do inbred BALB/c mice. The present studies were carried out to identify determinants of this strain difference. In a cross-fostering experiment it was shown that SFB colonization of the pups is determined by the strain of the pups themselves rather than by the strain of the nursing dam. Thus, maternal effects may not be involved in SFB colonization. In a cross-infecting experiment using germ-free and SFB-positive animals of the two mouse strains, it was found that ileal SFB colonization is determined by host characteristics rather than by origin of the SFBs. Thus, SFBs that are specific for a given mouse strain may not exist in the two strains of mice. It is concluded that the mouse strain difference in SFB colonization is determined by host characteristics, which probably have a genetic basis.