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Biomedical subjects

P Watts

Publications and source records attributed to P Watts.

82 records · Page 5Linked to original sources
PubMed1984

The reactivation by oximes of phosphonylated acetylcholinesterase: the possible erroneous interpretation of reactivating potency.

A comparative study of the reactivation by two oximes of acetylcholinesterase inhibited by several organophosphates has been made, with particular reference to the dependence of the degree of reactivation produced by an oxime (reactivating potency) upon the concentration of inhibited enzyme. In the case of one inhibitor it is demonstrated that the relative reactivating potency of the two oximes can be reversed by a change in experimental conditions. It is concluded that the measurement of the reactivation produced by two or more oximes, particularly when carried out under standardized conditions, is of little value in determining their relative reactivating potencies, and of negligible value in predicting their likely therapeutic effectiveness against organophosphate poisoning.

Acetylcholinesterase↗
PubMed1983

Interactions between acetylcholinesterase and tetra-N-alkylammonium ions.

A study of the mechanism of interaction of acetylcholinesterase with some simple tetra-N-alkyammonium ions has been made. Kinetic schemes have been proposed which are consistent with the experimental results observed in the enzyme-tetra-N-alkylammonium system in the presence of substrate and in the presence of an organophosphorus inhibitor.

Acetylcholinesterase↗
PubMedDate not supplied

Distinct responses of the herpes simplex virus and varicella zoster virus immediate early promoters to the cellular transcription factors Brn-3a and Brn-3b.

The related viruses herpes simplex virus (HSV) and varicella zoster virus (VZV) show distinct but related patterns of latent infection and reactivation in human sensory ganglia. The cellular POU family transcription factors Brn-3a and Brn-3b are expressed in sensory ganglia and bind to the TAATGARAT (R stands for purine) regulatory motifs in the immediate-early gene promoters of these viruses. We show that Brn-3a activates the full length HSV IE1 promoter whereas Brn-3b represses its activity. In contrast both Brn-3a and Brn-3b activate the full length VZV IE promoter. The response of the full length VZV promoter to Brn-3b is not observed with a minimal VZV immediate-early promoter lacking any TAATGARAT elements and cannot be restored by addition of either the upstream TAATGARAT-containing region of the HSV IE promoter or a VZV TAATGARAT-like element to this minimal promoter. The unique effect of Brn-3b on the full length VZV immediate early gene promoter may play a key role in the distinct pattern of latent infection and reactivation observed with this virus in vivo.

Cells, Cultured↗
PubMedDate not supplied

An evaluation of the decision tree approach for assessing priorities for safety testing of food additives.

In this publication we report an evaluation of the decision tree scheme of Cramer, Ford and Hall (1978) for assigning priorities for toxicity testing of chemicals. The original scheme has been modified to allow more chemical structures to be considered and to take into account recent advances in toxicology. The majority of the food additives permitted in either the UK, USA or Canada have been processed through the modified decision tree questionnaire and their classification compared with currently available chronic toxicity data. A large proportion of the additives (53/73) assigned to the lowest toxicity (I) class have a low order of chronic oral toxicity as do many of the compounds assigned to the moderate toxicity (II) class. Although the majority of the additives assigned to the highest toxicity (III) class are substantially more toxic than those in the lower toxicity classes, some relatively innocuous compounds reached this classification. In addition, a few toxic compounds were assigned to the lowest toxicity class. The reasons for these incorrect assignments are discussed. It was concluded that the decision tree approach, although less discriminating than originally suggested, remains a useful method for classifying compounds in terms of their probable toxicity and that further modifications to the tree could be made.

Accident Prevention↗
PubMedDate not supplied

Women's responses to the mammography experience.

BACKGROUND: Accounts of mammography-related anxiety, embarrassment, and pain have been barriers to women contemplating a mammogram. Because it is not known how many women have had bad mammography experiences, we designed a study to learn what women actually experience when they have a mammogram. METHODS: Two hundred fifty-five women were interviewed immediately after having a mammogram at three different breast-imaging centers in the Philadelphia area. RESULTS: Significant racial differences were noted in this study with reports of mammography-related anxiety and pain. Nonwhite women and women who had less than a high-school education reported significantly more anxiety about having a mammogram. Sixty percent of all women interviewed were anxious about having a mammogram; 20 percent of them reported being extremely anxious. White women reported pain more often than African-American women. Only 12 percent of the women reported that their physicians had explained the mammography procedure, but 61 percent of those women reported no anxiety versus 37 percent of women whose physicians did not explain the procedure. More than one-third (34 percent) of women having a first mammogram stated that their mammogram experience affected their future plans for having another. CONCLUSION: Extra physician or nurse time spent in explaining mammography to women could result in lower anxiety, higher levels of future intentions to get mammograms, and better experiences for the women themselves.

Anxiety↗