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A Gamble

Publications and source records attributed to A Gamble.

8 recordsLinked to original sources
PubMed2005

The effect of creosote on vitellogenin production in rainbow trout (Oncorhynchus mykiss).

As part of a broader investigation into the effects of creosote treatments on the aquatic biota in pond microcosms, we examined the possible implications for vitellogenin (Vtg) production in Oncorhynchus mykiss [rainbow trout (RT)]. Vtg is the precursor of egg yolk protein and has emerged as a useful biomarker of exposure to estrogenic substances. Our a priori intent was to assess the ability of the creosote treatments (nominal cresoste concentrations were 0, 3, and 10 microl/L immediately after the last subsurface addition) to induce estrogenic responses in RT. The data showed no evidence of an estrogenic response in the treated fish. During the course of the experiment, however, the fish matured and began to produce Vtg, probably in response to endogenous estrogen. A posteriori analysis of the Vtg data from the maturing fish showed that after 28 days, the plasma Vtg concentrations were about 15-fold lower in fish from the creosote-treated microcosms compared with fish from the reference microcosm. Although the experiment design does not permit mechanistic insights, our observation suggests that exposure of female fish to PAH mixtures such as creosote can impair the production of Vtg with possible health implications for embryos and larvae.

Animals↗
PubMed2005

Microlinguistic deficits in the narrative discourse of adults with traumatic brain injury.

BACKGROUND: Recent studies of microlinguistic impairments in the narrative discourse of adults with traumatic brain injury (TBI) have applied syntactic analyses, with some noting no deficits and others specific problems with sentence formulation. An alternative approach to examining the microlinguistic dysfunction in the discourse of individuals with TBI is through the use of propositional analysis. The advantage of propositional analysis is that it enables one to assess semantic complexity of utterances apart from sentence structure and grammaticality. AIMS: The present study applied propositional analysis to the story narratives of participants with TBI and participants with no brain injury (NBI). Specifically, the mean number of propositions within a sentence was tallied, in other words the participants' ability to insert multiple ideas into single surface sentences. It was hypothesized that the participants with TBI would produce fewer propositions per sentence because of organizational problems than the participants with NBI, regardless of level of education. METHODS AND PROCEDURES: Two story narratives (retelling and generation) previously elicited from the two participant groups (TBI (n = 53) and NBI (n = 42)) were analysed. For each language sample, the number of propositions was tallied and divided by the number of T-units. The resulting number, the propositional complexity index (PCI), was the average number of predicates per sentence. OUTCOMES AND RESULTS: Results indicated that the group with TBI produced significantly fewer propositions per T-unit. CONCLUSIONS: The present findings are in harmony with the notion that the participants with TBI studied presented with impairments of both micro- and macrolinguistic processes involved with the organization of semantic information in discourse. Clinical implications are discussed.

Adolescent↗
PubMed1999

An ELISA for brown trout (Salmo trutta) vitellogenin and its use in bioassays for environmental estrogens.

An enzyme linked immunosorbent assay (ELISA) was developed for the detection of the egg yolk precursor vitellogenin (Vg) in plasma of brown trout (Salmo trutta). Purified Vg from a 17 beta-estradiol-induced trout was used as the competing antigen in the ELISA which is based on polyclonal antibodies. The ELISA's performance was optimized and characterized. The assay's working range was (25-500 ng ml-1), its sensitivity was (10.5 ng ml-1), and it had an intra-assay coefficient of variation of less than 10% between 30 and 1000 ng ml-1. The ELISA was used in bioassays for the detection of environmental estrogens, including estrogen mimics, in whole and fractionated industrial waste waters. Those bioassays were based on intraperitoneal (i.p.) injection-, static renewal-, and flow through exposure systems. The response threshold of both bioassays is limited to 1-2 micrograms ml-1 Vg by a low level plasma interference that was regularly detected in plasma from non-induced male fish. The responsiveness of the bioassays was characterized using progressive doses of 17 beta-estradiol. The i.p.-based assay, which was responsive to at least 100 micrograms kg-1 of 17 beta-estradiol, was used to screen extracts of pulp mill effluent and black liquor for estrogenic effects. Neither extract induced Vg in our assay. The i.p. assay was also used to test 4-tert-octylphenol (OP) and the PAH derivative, retene, for estrogenic activity. OP induced Vg in the i.p.-exposed fish; no Vg induction was detected in the retene-exposed fish. The static renewal bioassay, which was responsive to at least 0.1 microgram ml-1 of 17 beta-estradiol over a 15-day exposure period, was used to screen whole pulp mill effluents for estrogenic effects. No Vg induction was detected in the effluent-treated fish.

Animals↗