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T McCann

Publications and source records attributed to T McCann.

12 recordsLinked to original sources
PubMed2003

Sampling Broad Habitat change to assess biodiversity conservation action in Northern Ireland.

A habitat monitoring programme, the Northern Ireland Countryside Survey, carried out by the University of Ulster for the Department of the Environment for Northern Ireland, is described. It was based on a random sample of quarter kilometer grid squares, stratified by multivariate land classification. Estimates of change in habitat area between 1987-1992 and 1998 are presented and used to assess policy-related priorities for biodiversity conservation action in widespread habitats in Northern Ireland (NI). The basis of the assessment is Broad Habitats, a classification developed as part of the United Kingdom (UK) Biodiversity Action Plan. Improved Grassland, Neutral Grassland and Bog Broad Habitats occupy the largest area of NI, which holds a large proportion of the UK Neutral Grassland and Fen Marsh and Swamp Broad Habitat resource. The greatest net area increases with time were in Improved Grassland (33%), Coniferous Woodland (12%) and Broadleaved, Mixed and Yew Woodland (9%). The greatest net area decreases were in Neutral Grassland (-32%), Arable and Horticulture (-25%), Fen, Marsh and Swamp (-19%), Bog (-8%) and Calcareous Grassland (-7%). These changes are a function of agriculture, public and private forestry, building construction and peat cutting for fuel. The Key biodiversity issue is seminatural Broad Habitat loss, in particular, Neutral Grassland and Fen, Marsh and Swamp, highlighting the lack of effective action for protecting biodiversity in the countryside as a whole. The extent to which current land use is shown to be driving change, indicates that biodiversity conservation action through implementing landscape-scale agri-environment measures could deliver major biodiversity gains. The reliable information on recent changes, provided by the Northern Ireland Countryside Survey, has been used to guide conservation planning. Future re-survey will allow the effectiveness of the conservation strategy as it applies to the countryside as a whole, to be determined. As decisions on land use increasingly have a strong European dimension, concerted action for protecting biodiversity in the countryside as a whole is needed. This would be promoted by a structured sampling approach, based on standard habitat mapping procedures.

Agriculture↗
PubMed1999

Cytokines increase neonatal cardiac myocyte calcium concentrations: the involvement of nitric oxide and cyclic nucleotides.

Neonatal rat cardiac myocytes were treated with cytokines, with or without the nitric oxide synthase (NOS) inhibitors N-monomethyl-L-arginine (LNMMA) and N-nitro-L-arginine methyl ester (LNAME), and systolic and diastolic calcium levels were measured by fluorescence spectrophotometry and confocal microscopy. Time-dependent changes following interferon-gamma (IFN-gamma) treatment revealed a continuing increase in intracellular calcium, which was reduced with LNMMA, but not with LNAME. Increases in calcium also occurred with interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), but not to the extent seen with IFN-gamma. Increased cyclic guanosine monophosphate (cGMP) was involved in the results described with short-term (2 hr) TNF-alpha and long-term (18 hr) IFN-gamma treatments. Short-term exposure to IFN-gamma produced an increase in cyclic adenosine monophosphate (cAMP) and also an initial increase in the myocyte-bearing rate, with calcium levels either (i) subsequently returning to control levels while maintaining a fast beating rate or (ii), retaining a high systolic calcium level, but beating at control rates. Treatment with both IL-1beta and IFN-gamma stabilized the beating rate of the cells on some occasions. Shortening of myocytes increased with isoproterenol and following treatment with IFN-gamma, while isoproterenol stimulation of IFN-gamma-treated cells revealed increased contractile activity after short, but not long, treatment. LNMMA, but not reduced the increased contractile response with short-term IFN-gamma treatment. Our findings suggest that TNF-alpha acts via a cGMP-dependent pathway, whereas the actions of IFN-gamma involve adenylate cyclase, and possibly a NO-forming mechanism and cGMP pathway as well. It is also apparent that the two NO inhibitors function via different mechanisms or that LNMMA has a direct effect on the calcium-signaling pathway.

Analysis of Variance↗
PubMed1996

The validity of spot urine samples for low-level occupational mercury exposure assessment and relationship to porphyrin and creatinine excretion rates.

Hg and porphyrin levels in single void urine specimens (spot samples) were compared with calculated 24-hr urine levels in 35 (20 [correction of 25] male and 15 female) practicing dentists who had been occupationally exposed to low levels of elemental Hg. The study aimed to: 1) determine the individual variability for Hg and porphyrin concentrations in spot samples over a 24-hr period; 2) test for the presence of diurnal variation in urinary Hg and porphyrin concentrations; and 3) determine the time of day at which a spot sample would give a Hg concentration closest to the 24-hr average concentration. Results confirmed previous reports of a first-order diurnal pattern with a mid-morning peak for Hg concentration (P < .001). A second-order model best described creatinine excretion (P = .0089), with peaks at about 5:00 and 19:00. The use of creatinine adjustment for Hg concentration significantly reduced the intraindividual variation around the diurnal curve. No diurnal patterns were found for any of the porphyrins examined. We recommend that, for small clinical studies using urinary Hg concentration, 24-hr sampling would be ideal, but that for mass screenings and cross-sectional studies, spot samples may be useful because they correlate fairly well with 24-hr averages (creatinine adjusted, r = 0.61; unadjusted, r = 0.74). Because of the existence of diurnal variation, for all cases using serial sampling attention should be paid to time of day.

Adult↗
PubMed1993

Gender and age differences in food cognition.

Results from three studies relevant to a model of food cognition based on the evaluative dimensions pleasure, health, and convenience are reported. In the first study, discriminant analyses of the evaluative ratings (n = 248) of 35 meals and snacks yielded significant gender and age differences on the pleasure and health dimensions. Separate factor analyses of the pleasure and health ratings revealed that males and females grouped foods differently on these criteria. The factor analysis of convenience ratings suggested that males and females perceive the meaning of convenience differently. In the second study, 336 college students rated 27 meals on the three evaluative dimensions and also indicated their preferences for each meal. Multiple regression analyses showed that preferences could be significantly predicted, and other results showed that as compared to males, females give higher health, pleasure and convenience ratings to healthy meals. The third study employed a modified free association technique to investigate gender and age differences in the meanings of nine familiar foods. Data from 96 males and females aged 18 to 86 revealed a substantial variety of significant age and gender differences for specific foods. It is suggested that taken together, these results indicate important cognitive and affective sources for gender and age-related food attitudes.

Adolescent↗
PubMed1988

Hypnotically induced pseudomemories--sampling their conditions among hypnotizable subjects.

Three studies are reported in a program of research that investigated a range of parameters affecting individual differences in the incidence of hypnotically induced pseudomemory among hypnotizable subjects. Study 1 replicated Laurence and Perry's (1983b) base rates for hypnotically induced pseudomemory response among hypnotizable subjects; in Study 2 the same response was analyzed under more strictly controlled stimulus conditions. Study 3 was an investigation of the impact of a broader range of stimulus events on response and a more sensitive test of the hypothesis that individual differences in pseudomemory effects are tied essentially to the social context of hypnosis. In all three studies, independent groups of subjects were tested who were highly responsive to hypnotic suggestion. Data indicated that the incidence of pseudomemory response was stable and consistent when stringent criteria of scoring were adopted. Also, for some subjects, real and suggested memories were maintained at one and the same time when hypnotically induced memory was examined in different test settings, suggesting that pseudomemories do not permanently overlay real experience. Overall, contextual factors appeared to play a major role among susceptible subjects in determining the nature and incidence of hypnotically induced pseudomemories.

Adult↗
PubMed1976

Development of a purified cholera toxoid. III. Refinements in purification of toxin and methods for the determination of residual somatic antigen.

The addition of an ultrafiltration step to the purification procedures previously described for cholera toxin (Rappaport et al., (1974) permitted the preparation of highly purified antigenic toxoids essentially free of somatic antigen(s). The purity of such toxoids is established: (i) by the absence of more than about one part limulus amebocyte lysate (LAL)-positive endotoxin per 10(5) parts toxoid and (ii) by the inability of the toxoids to elicit a significant rise in rabbit vibriocidal antibody. The antigenicity of the toxoids is demonstrated by their ability to produce the same high levels of rabbit serum antitoxin as are produced by comparable toxoids containing small amounts of somatic antigen. The results also indicate that amounts of somatic antigen of the order of less than or equal to 1 mug/100 mug of toxoid do not exert an adjuvant effect on the toxoid, at least with respect to circulating antitoxin. Other data show that, where present, the ability of somatic antigen to elicit vibriocidal antibody is influenced by the immunization schedule employed and that a correlation exists between the LAL-determined endotoxin content of the toxoids and their ability to stimulate vibriocidal antibody. Somatic antigen-free toxoids, purified and tested by the refinements herein described, were prepared for use in the National Institutes of Health sponsored field trials, and data pertaining to their purity and antigenic properties are presented.

Animals↗
PubMed1974

Development of a purified cholera toxoid. II. Preparation of a stable, antigenic toxoid by reaction of purified toxin with glutaraldehyde.

Evidence is presented which confirms that cholera toxoids obtained by reaction of purified toxin with Formalin possess the ability to partially reactivate both in vivo and in vitro. At the same time, conditions are presented for the preparation of stable, antigenic cholera toxoids by reaction of purified toxin with glutaraldehyde. Treatment of purified cholera toxin with approximately 200 mol of glutaraldehyde per mol of toxin at pH 7.8 reproducibly resulted in the preparation of toxoids which: (i) possessed less than 20 bluing doses per 100 mug; (ii) did not reactivate in vivo or in vitro; (iii) precipitated with, and neutralized antitoxin; (iv) elevated prolonged serum antitoxin in immunized rabbits; (v) protected immunized guinea pigs against toxin skin challenge; and (vi) lent themselves to enhanced antigenicity by means of an in situ adjuvant system which may be suitable for man. Acrylamide gel electrophoresis and molecular sieve chromatography of a series of glutaraldehyde-derived toxoids suggested that the reaction products consisted of monomeric and polymeric species and that the proportion of higher-molecular-weight species was determined by the relative concentrations of toxin and glutaraldehyde. The results suggested a relationship between complete and irreversible elimination of toxicity and the formation of higher-molecular-weight toxoids.

Adsorption↗