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C J Lewis

Publications and source records attributed to C J Lewis.

At least 37 records · Page 2Linked to original sources
PubMed1999

Health claims and observational human data: relation between dietary fat and cancer.

The US Food and Drug Administration review that provided the basis for authorizing a food-label health claim linking the risk of cancer to dietary fat intake illustrated several considerations in the use of epidemiologic data, and observational data in particular, to support dietary recommendations. The review suggested the need for clear and established criteria for judging the quality of observational human data as well as the importance of making the evaluation process for individual studies transparent and organized. The review, which provided for a claim in the absence of controlled human studies, also suggested that observational data may play a greater role when the nature of the relation to be described by a health-claim statement is broad and general rather than targeted and specific. Of particular importance was the relevance of available data to the questions inherent in showing a diet-disease relation, the need to consider the totality of the evidence, and the key role that existing authoritative reports must play in establishing the basis for relation.

Animals↗
PubMed1998

Restriction endonuclease profiles of orf virus isolates from the British Isles.

A comparison of DNA profiles of representative isolates of orf virus, obtained using four different restriction endonucleases (RE), showed that the enzyme EcoRI could be used to discriminate between wild-type virus isolates and vaccine strains. The enzyme was used to compare the RE profiles of orf virus isolates from 43 outbreaks of orf that occurred in vaccinated flocks between 1988 and 1993; 21 outbreaks yielded wild-type virus, 10 yielded vaccine viruses, three produced both vaccine and wild-type viruses and no clear result was obtained from nine of the outbreaks. From the 21 outbreaks yielding wild-type viruses, 28 orf virus isolates had clear RE profiles and 15 distinct RE profiles were recorded. Usually only one virus type was associated with each outbreak but from two farms, two different wild-type viruses were recovered. No predominant genotype was identified, with four RE profile types being recovered for more than one outbreak. From the more severe form of orf involving the buccal cavities of lambs only wild-type viruses were recovered, with at least four different genotypes being represented.

Animals↗
PubMed1998

Sudden death in sheep associated with Clostridium sordellii.

Clostridium sordellii was isolated from 37 sheep, in 29 flocks, which died suddenly between 1993 and 1995. The sheep were of all ages, but the most severe gross lesions affected lambs four to 10 weeks of age. In older weaned lambs and ewes the gross changes were less marked and more variable. Thirty sheep suffering from a variety of other conditions were examined and C sordellii was not isolated. The isolation of C sordellii has been reported only twice before from sheep in Britain, and on both occasions no detailed investigations were described. The evidence from this study indicates that C sordellii should be considered when investigating the cause of sudden death in sheep of all ages in Britain.

Animals↗
PubMed1998

2',3'-O-(2,4,6- trinitrophenyl) adenosine 5'-triphosphate (TNP-ATP)--a nanomolar affinity antagonist at rat mesenteric artery P2X receptor ion channels.

1. P2X receptor activation by alpha,beta-meATP evoked inward currents in acutely dissociated rat mesenteric artery smooth muscle cells and contractions of whole artery rings. 2. The selective P2X1 and P2X3 receptor antagonist TNP-ATP inhibited P2X receptor mediated inward currents in response to 3 microM alpha,beta-meATP (an approximately EC90 concentration) with an IC50 of approximately 2 nM. This provides further evidence that the P2X receptor underlying membrane depolarisation associated with P2X receptor activation can be accounted for by the expression of P2X1 receptors. 3. TNP-ATP inhibited alpha,beta-meATP induced contractions with an IC50 of approximately 30 microM and had non-specific effects on smooth muscle contraction. 4. The reduced potency of TNP-ATP in whole tissue experiments probably reflects the breakdown of TNP-ATP by nucleotidases. Thus, TNP-ATP is of limited use in whole tissue experiments as a P2X receptor antagonist.

Adenosine Triphosphate↗
PubMed1995

Reduction of vasoconstriction mediated by neuropeptide Y Y2 receptors in arterioles of the guinea-pig small intestine.

Brief applications of a high-K+ solution were used to evoke transient constrictions of arterioles from the guinea-pig small intestine. Analogues of neuropeptide Y (NPY) selective for Y2-receptors reduced the constrictions, whereas NPY or a Y1-selective analogue potentiated the constrictions. We conclude that arteriolar smooth muscle has both Y1 and Y2 receptors, and suggest that Y2 receptors inhibit vasoconstriction by modulating the opening of voltage-sensitive Ca2+ channels. This may be related to the role of NPY that is present in some vasodilator nerves.

Animals↗
PubMed1995

Evaluating food fortification options: general principles revisited with folic acid.

OBJECTIVES: This article uses folic acid as an example to illustrate some of the complex issues and general principles that emerge when evaluating fortification of the food supply as one possible means to address a public health recommendation. METHODS: Distributions of current daily folate intakes from conventional foods and dietary supplements were estimated. Intakes that might result from fortification of cereal-grain products and ready-to-eat cereals at various levels for eight age-gender groups were also estimated by using the US Department of Agriculture's 1987-1988 Nationwide Food Consumption Survey. RESULTS: The results illustrate that fortification of the US food supply tends to increase folate intakes of consumers at the high end of the intake distribution curves in the general population to a greater extent than it affects consumers at the low end of the intake distribution curves in the target population. CONCLUSIONS: The effectiveness of food fortification options for a target population and the safety for the general population impose conflicting challenges that must be considered concurrently when making decisions about fortifying the US food supply.

Adolescent↗
PubMed1992

Unseasonal twins.

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Anestrus↗
PubMed1992

Isolation of a novel siderophore from Pseudomonas cepacia.

A novel iron-binding compound was identified in ethyl acetate extracts of the supernates from Pseudomonas cepacia cultures. This compound, named azurechelin, was produced by 88% of P. cepacia strains isolated from the respiratory tract. Production of azurechelin was regulated by the iron concentration in the culture medium. Azurechelin enhanced the growth of P. cepacia in a medium containing transferrin 200 mg/L. Azurechelin released iron from transferrin in an equilibrium dialysis assay, suggesting that it could complete with transferrin for iron. Azurechelin could also stimulate iron uptake by P. cepacia. This siderophore appeared to have a novel structure with neither the typical characteristics of catechol nor of hydroxamate compounds.

Biological Transport↗
PubMed1992

Do time trends in food supply levels of macronutrients reflect survey estimates of macronutrient intake?

BACKGROUND: Two types of data may be used to estimate trends in food and nutrient intake by the US population: per capita food supply estimates and survey estimates of individual intake. Because these data vary markedly in measurement goals and methods, we examined whether trends in food supply and survey intake estimates for fat, carbohydrate, and protein are reflective of one another. METHODS: The data selected for comparison included all available survey estimates of mean intake by the US population (i.e., periodic estimates from 1965 to 1988) and all available per capita food supply estimates from a comparable time period (i.e., annual estimates from 1965 to 1985). RESULTS: The two types of data generally did not reflect the same trends. Furthermore, expressing macronutrient levels as percentage of calories rather than in grams affected the trend relationships. CONCLUSIONS: Our findings indicate that caution is needed in the selection and application of available data to estimate trends in macronutrient intake by the US population and in the interpretation of these data with regard to public health research, policies, and programs.

Data Collection↗