Biomedical subjects

Timothy P Smith

Publications and source records attributed to Timothy P Smith.

3 recordsLinked to original sources

PubMed2004

Risk assessment of oral exposure to diisononyl phthalate from children's products.

Dialkyl phthalates are plasticizers used in household products made from polyvinyl chloride (PVC). Diisononyl phthalate (DINP) is the principal phthalate in soft plastic toys. Because DINP is not tightly bound to PVC, it may be released when children mouth PVC products. The potential chronic health risks of phthalate exposure to infants have been under scrutiny by regulatory agencies in Europe, Canada, Japan, and the U.S. This report describes a risk assessment of DINP exposure from children's products, by the U.S. Consumer Product Safety Commission (CPSC) staff. This report includes the findings of a CPSC Chronic Hazard Advisory Panel (CHAP) which: (1) concluded that DINP is unlikely to present a human cancer hazard and (2) recommended an acceptable daily intake (ADI) level of 120 microg/kg-d, based on spongiosis hepatis in rats. The risk assessment incorporates new measurements of DINP migration rates from 24 toys and a new observational study of children's mouthing activities, with a detailed characterization of the objects mouthed. Probabilistic methods were used to estimate exposure. Mouthing behavior and, thus, exposure depend on the child's age. Approximately 42% of tested soft plastic toys contained DINP. Estimated DINP exposures for soft plastic toys were greatest among children 12-23 months old. The mean exposure for this age group was 0.08 (95% confidence interval 0.04-0.14) microg/kg-d, with a 99th percentile of 2.4 (1.3-3.2) microg/kg-d. The authors conclude that oral exposure to DINP from mouthing soft plastic toys is not likely to present a health hazard to children. The opinions expressed by the authors have not been reviewed or approved by, and do not necessarily reflect the views of, the U.S. Consumer Product Safety Commission. Because this material was prepared by the authors in their official capacity, it is in the public domain and may be freely copied or reprinted.

Administration, Oral↗

PubMed2003

Development and testing of a high-density cDNA microarray resource for cattle.

A cDNA microarray resource has been developed with the goal of providing integrated functional genomics resources for cattle. The National Bovine Functional Genomics Consortium's (NBFGC) expressed sequence tag (EST) collection was established in 2001 to develop resources for functional genomics research. The NBFGC EST collection and microarray contains 18,263 unique transcripts, derived from many different tissue types and various physiologically important states within these tissues. The NBFGC microarray has been tested for false-positive rates using self-self hybridizations and was shown to yield robust results in test microarray experiments. A web-accessible database has been established to provide pertinent data related to NBFGC clones, including sequence data, BLAST results, and ontology information. The NBFGC microarray represents the largest cDNA microarray for a livestock species prepared to date and should prove to be a valuable tool in studying genome-wide gene expression in cattle.

Animals↗

PubMed2003

Optimising high-intensity treadmill training using the running speed at maximal O(2) uptake and the time for which this can be maintained.

The aim of this study was to compare the effects of two high-intensity, treadmill interval-training programs on 3000-m and 5000-m running performance. Maximal oxygen uptake (.VO(2max)), the running speed associated with .VO(2max) (v.VO(2max)), the time for which v.VO(2max) can be maintained (T(max)), running economy (RE), ventilatory threshold (VT) and 3000-m and 5000-m running times were determined in 27 well-trained runners. Subjects were then randomly assigned to three groups; (1) 60% T(max), (2) 70% T(max) and (3) control. Subjects in the control group continued their normal training and subjects in the two T(max) groups undertook a 4-week treadmill interval-training program with the intensity set at v.VO(2max) and the interval duration at the assigned T(max). These subjects completed two interval-training sessions per week (60% T(max)=six intervals/session, 70% T(max) group=five intervals/session). Subjects were re-tested on all parameters at the completion of the training program. There was a significant improvement between pre- and post-training values in 3000-m time trial (TT) performance in the 60% T(max) group compared to the 70% T(max) and control groups [mean (SE); 60% T(max)=17.6 (3.5) s, 70% T(max) =6.3 (4.2) s, control=0.5 (7.7) s]. There was no significant effect of the training program on 5000-m TT performance [60% T(max)=25.8 (13.8) s, 70% T(max)=3.7 (11.6) s, control=9.9 (13.1) s]. Although there were no significant improvements in .VO(2max), v.VO(2max) and RE between groups, changes in .VO(2max) and RE were significantly correlated with the improvement in the 3000-m TT. Furthermore, VT and T(max) were significantly higher in the 60% T(max) group post- compared to pre-training. In conclusion, 3000-m running performance can be significantly improved in a group of well-trained runners, using a 4-week treadmill interval training program at v.VO(2max) with interval durations of 60% T(max).

Adult↗