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Biomedical subjects

P Schofield

Publications and source records attributed to P Schofield.

At least 91 records · Page 5Linked to original sources

Predicting attempts and sustained cessation of smoking after the introduction of workplace smoking bans.

Examined predictors of smoking cessation attempts and predictors of the outcome of those attempts after the introduction of a workplace smoking ban. Smokers were surveyed in the month before the ban came into force, and variables collected at that time were used to predict outcomes 6 months later. Data from 491 respondents who were smokers at the time of the initial survey were used, and a set of potential predictor variables was chosen on both theoretical and empirical grounds. Making a cessation attempt was predicted by the strength of desire to quit and, to less extent, by not having been subject to extensive restrictions on smoking before the mandated ban, having tried to quit before, perceiving oneself high in ability to quit, and being worried about smoke at work. For the outcome of cessation attempts among those who tried, success was best predicted by low levels of a composite habit strength variable and, to less extent, by desire to quit, no previous attempts to quit, the existence of social supports for quitting, and educational status. Although cognitive variables were important in predicting attempts, they played only a minor role in predicting maintenance. Behavioral and environmental variables contributed slightly to prediction of attempts and strongly to prediction of maintenance.

Adult↗

Development of a strategy to encourage attendance for screening mammography.

The present study describes a method for the data-driven structuring of interventions to increase participation in screening mammography. We interviewed 668 randomly selected women from the target population of an Australian pilot screening mammography program before this Program commenced. The aims of the study were to use cross-sectional data to determine factors which predicted women's intentions regarding attendance at the Program, and on the basis of these results to develop optimal strategies to encourage attendances. Of the sample, 64% said they intended to go to the Program, while 11% were unsure. A number of variables were significantly associated with intention and regression analysis was used to determine the best model for predicting intention. Ten variables entered the final regression model: the intensity of thought about getting breast cancer; a belief that early detection is extremely desirable and that screening mammograms are accurate; having had a Pap test within the last 2 years; a belief that health is controlled by chance; perceived ease of getting to the hospital; subjective familiarity with the hospital location of the Program; age; having heard about screening mammography; and a feeling of personal susceptibility to breast cancer. This model explained 20% of the variance in intention to have a mammogram (R 2 = 0.20, F(10,492) = 12.08; P less than 0.0001). The practical applications of these findings are discussed in this report. It is recommended that if a campaign were to concentrate on changing women's perceptions on the dimensions found to be significantly associated with intention, then it would have maximum chance of encouraging attendance amongst women in the target population. The strategies we have developed based on these findings are discussed in this paper.

Aged↗

Growth-related protein kinases.

A protein kinase cascade is involved in the action of some mitogens. The cascade begins with receptor tyrosine kinase activation by growth factors. The resulting signal is transmitted into cells via phospholipid metabolism which produces a variety of second messengers and by intracellular protein kinase activation. The signal is then propagated and disseminated via a network of other protein kinases and protein phosphatases. Recent research suggests that ribosomal protein S6 kinase and casein kinase II are two important elements in the kinase cascade that leads to the initiation of growth. The nature and some properties of these hitherto lesser known enzymes is considered.

Animals↗

The expression of the TGF beta 1 gene in the first trimester human eye and other embryonic organs.

We have examined the expression of the transforming growth factor beta 1 gene in a variety of tissues in the developing human embryo. Northern blot analysis revealed the presence of TGF B1 mRNA in the 10-12 week old eye as well as in most first trimester organs with the notable exception of the yolk sack. In an attempt to determine the topographical distribution of TGF B1 transcripts within the eye, we found that messenger RNA levels were higher in the posterior regions of the eye globe.

Embryo, Mammalian↗

Part-time women general practitioners--workload and remuneration.

A postal questionnaire survey was conducted comparing the workload and remuneration of part-time women principals in group practices in the Northern and Oxford regions. Part time was defined as receiving less than a full profit share at parity. Of 501 women principals 308 (62%) responded of whom 146 (47%) were part-time. Respondents were asked to record aspects of workload over a four-week period for themselves and their full-time partner who did the most sessions within the practice. The results showed that although two-thirds of the part-timers had 50% or less of a full profit share, part-time principals overall did about 76% of the daytime clinical work (surgeries and home visits) done by their full-time partners, excluding specialized clinics. The lower the profit share the wider this discrepancy. Although 33% of the respondents did not out-of-hours work, the remainder did more than their profit share would indicate. Twenty per cent of the 116 principals with 40% or more of a full profit share and 57% of the 30 principals with less than 40% of a full profit share felt that their share was unfair. Lack of involvement in practice business and feeling that opinions did not carry equal weight were associated with feelings of unfairness.

Female↗

Wiedemann-Beckwith syndrome.

The Wiedemann-Beckwith syndrome (WBS) comprises an accumulation of multiple congenital anomalies. Exomphalos, macroglossia and gigantism are considered the most common manifestations, hence the alternative designation EMG-syndrome. The syndrome carries with it an increased risk of developing specific tumours. One of the more frequent metabolic changes is transient neonatal hypoglycaemia, the result of increased insulin secretion. Inheritance of the syndrome remains uncertain. Most cases are sporadic, but a number of familial cases have been reported. Present evidence suggests that WBS is an autosomal dominant trait with variable expressivity. This review summarizes the abundant literature on the subject and discusses recent molecular genetic developments that may explain the interrelationship between the clinical abnormalities, metabolic disturbances and development of tumours.

Beckwith-Wiedemann Syndrome↗

The similarity of attitudes towards personal and impersonal types of authority among adolescent schoolchildren.

This paper examines the extent to which the attitudes of young adolescents towards personal and impersonal types of authority are differentiated. Reliable measures of attitudes towards personal authorities (parents and teachers) and impersonal authorities (the police and the law) were developed with a preliminary sample of 155 secondary school students. These measures were employed with further samples of (a) third year High School students (n = 77) who also completed the Keeves (1974) Attitudes to School and School Learning Scale, and (b) first year High School students (n = 250) who also completed the Ray and Jones (1983) self-report measures of authority-salient behaviours in relation to their parents and teachers. The attitudes of the students were relatively pro-authority and did not differ according to gender. In general, the younger group of students were the more pro-authority, significantly so on the measures of attitude towards personal authorities. For each sample the pro-authority attitude measures loaded substantially (greater than 0.6) on the first factor of a principal components analysis. Correlations between these measures and (a) attitudes to school and school learning and (b) reported authority-salient behaviours were positive and, in general, significant for each sex. Overall, the results provided little support for the view that attitudes towards personal and impersonal type of authority are dissimilar.

Adult↗

Expression of growth regulatory genes in primary human testicular neoplasms.

Seven testicular tumours of different histological type--two seminomas, two teratomas/teratocarcinomas/embryonal carcinomas, one mixed seminoma/teratoma, one Leydig cell tumour and one testicular lymphoma--were examined for the expression of four potentially growth regulatory genes by Northern blotting. Seven out of seven testicular tumours contained transcripts that hybridized with a human insulin cDNA-probe whereas only four out of seven tumours contained IGF II transcripts. One tumour contained high levels of LDL-receptor transcript whereas all seven tumours contained significant quantities of HMG-CoA-reductase mRNA.

DNA↗

A comparison of the ventilatory, cardiovascular and metabolic effects of salbutamol, aminophylline and vasoactive intestinal peptide in normal subjects.

Intravenous infusion of placebo for 30 min followed by either salbutamol 10 micrograms min-1, aminophylline 0.2 mg kg-1 min-1 or vasoactive intestinal peptide (VIP) 6 pmol kg-1 min-1 for 30 min was performed in a single blind fashion in six normal volunteers. Both salbutamol and aminophylline increased minute ventilation, (P less than 0.05) the mean increase being 26% and 19% respectively. Aminophylline also increased the ventilatory response to carbon dioxide by 47% (P less than 0.05) when measured by hyperoxic rebreathing, whereas salbutamol and VIP were without significant effect. All three drugs caused a tachycardia, mean increase in the pulse being 16, 8 and 2 beats min-1 for salbutamol, aminophylline and VIP respectively, and aminophylline also increased both systolic and diastolic blood pressure, mean arterial pressure increasing by 14 mmHg. VIP caused haemoconcentration and salbutamol the expected changes in plasma biochemistry. Plasma catecholamines increased slightly during drug infusion, although this effect is unlikely to be important.

Adult↗

Management of surgery.

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Ambulatory Surgical Procedures↗

Desensitization of the beta-adrenoceptor of lymphocytes from normal subjects and asthmatic patients in vitro.

1 A lymphocyte culture method has been developed for studying in vitro the effect of prolonged exposure (24 h) to isoprenaline (10(-8) to 10(-6) mol/l) and prostaglandin E1 (PGE1; 2.8 x 10(-6) mol/l). 2 The cyclic AMP response to isoprenaline is reduced by prolonged exposure to isoprenaline. The degree of desensitization is in proportion to the concentration of isoprenaline in the culture medium. 3 Culture with isoprenaline does not reduce the cyclic AMP response to PGE1. 4 Culture for 24 h with PGE1 (2.8 x 10(-6) mol/l) reduces the cyclic AMP response to PGE1. It also significantly reduces the response to isoprenaline. 5 Lymphocytes from asthmatic patients show a similar degree of desensitization to isoprenaline (after 24 h culture with isoprenaline) to that seen in lymphocytes from normal subjects. 6 A modified assay for phosphodiesterase (PDE) activity was developed. PDE activity increased 24.5% (P less than 0.02) after culture with PGE1 but was not significantly affected by culture with isoprenaline. 7 It is concluded that desensitization caused by prolonged exposure to various stimulators of adenylate cyclase is an event dependent on several components, not all of which are yet defined.

3',5'-Cyclic-AMP Phosphodiesterases↗

Kinetic mechanism of tRNA nucleotidyltransferase from Escherichia coli.

A kinetic analysis of the incorporation of AMP into tRNA lacking the 3'-terminal residue by tRNA nucleotidyltransferase (EC 2.2.7.25) from Escherichia coli is presented. Initial velocity studies demonstrate that the mechanism is sequential and that high concentrations of tRNA give rise to substrate inhibition which is noncompetitive with respect to ATP. In addition, the substrate inhibition is more pronounced in the presence of pyrophosphate, which suggests the formation of an inhibitory enzyme-pyrophosphate-tRNA complex. Noncompetitive product inhibition is observed between all possible pairs of substrates and products. ADP and alpha,beta-methylene adenosine triphosphate are competitive dead end inhibitors of ATP, while the latter is a noncompetitive dead end inhibitor of the tRNA substrate. A nonrapid equilibrium random mechanism is proposed which is consistent with these data and offers an explanation for the noncompetitive substrate inhibition by tRNA.

Adenosine Diphosphate↗

Purification and some properties of Escherichia coli tRNA nucleotidyltransferase.

Adenylyl (cytidylyl)-tRNA nucleotidyltransferase (ATP (CTP): tRNA adenylyl (cytidylyl)transferase, EC2.7.7.25) has been purified 11,800-fold from a crude extract of Escherichia coli B in an overall yield of 23%. The key step in this purification is the use of a tRNA-Sepharose affinity column. The purified enzyme has a specific activity of approximately 280 mumol of AMP incorporated/min/mg of protein at 37 degrees and has a molecular weight of 52,000 as determined by sodium dodecyl sulfate gel electrophoresis of Sephadex chromatography. The turnover number of the pure enzyme, under optimal assay conditions, is estimated as 21,000, and we believe it constitutes only o.oo6% of the total cellular protein. Both AMP- and CMP-incorporating activities have an identical isoelectric point of 5.85. The AMP-incorporating activity of the enzyme is inhibitied by some transition metal chelating agents but not by others.

Escherichia coli↗