Telecom management: managers must plan for the future.
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Computer Communication Networks↗
Biomedical subjects
W C Smith
Publications and source records attributed to W C Smith.
Variation in coronary risk factors by social status: results from the Scottish Heart Health Study.
The relationship between social status and coronary heart disease in the United Kingdom is well established with the more socially disadvantaged being at higher risk. There is also evidence that the levels of most of the known coronary risk factors vary with social status in a way consistent with their relationship to coronary heart disease. Using data from the Scottish heart health study the aim of this study was to quantify, for men and women, the variation in four of the main coronary heart disease risk factors--smoking, serum total cholesterol level, blood pressure and obesity--according to a number of social factors--occupational social class, housing tenure, level of education and employment status. The analyses used both mean risk factor levels as well as the percentages above suggested cut off levels, in order to provide estimates of the percentage of people at risk. All the risk factors, apart from total cholesterol level in men, showed fairly consistent variation across social groups with the more socially disadvantaged being at higher risk. Similar social variation was found for the percentages above the cut off levels, and these indicate that nearly 60% of the Scottish population aged 40-59 years, have one or more risk factors for coronary heart disease. These results suggest that some targeting of health education and management is appropriate, and this is especially relevant as the reforms to the National Health Service set health targets for health authorities and encourage general practitioners to provide health promotion services.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Injected Xwnt-8 RNA acts early in Xenopus embryos to promote formation of a vegetal dorsalizing center.
Expression cloning from a pool of gastrula cDNAs identified the Wnt family member Xwnt-8 as having dorsal axis-inducing activity in Xenopus embryos. Microinjected Xwnt-8 mRNA was able to rescue the development of a dorsally complete anterior-posterior axis in embryos ventralized by exposure to UV light. Axis induction was observed in embryos injected in either marginal or vegetal blastomeres at the 32-cell stage. Vegetal blastomeres receiving Xwnt-8 mRNA contributed progeny not to the induced dorsal axis, but to the endoderm, a result consistent with Xwnt-8 causing cells to act as a Nieuwkoop center (the vegetal-inducing component of normal dorsal axis formation), rather than as a Spemann organizer (the induced dorsal marginal zone component that directly forms the dorsal mesoderm). Xwnt-8, which is normally expressed ventrally in midgastrula and neurula embryos, appears to mimic, when injected, maternally encoded dorsal mesoderm-inducing factors that act early in development.
Animals↗
A retinoic acid response element is present in the mouse cellular retinol binding protein I (mCRBPI) promoter.
Genomic and cDNA sequences for the mouse cellular retinol binding protein I (mCRBPI) are presented. A specific cis-acting element responsible for retinoic acid (RA) inducibility of the mCRBPI promoter was identified and characterized. Deletion mapping of a CRBPI promoter--chloramphenicol acetyltransferase reporter gene construct localized this element to a 259 bp restriction fragment located approximately 1 kb upstream from the transcription start-site. A sequence closely resembling the previously characterized RA response element (RARE) of the RA receptor beta 2 (RAR-beta 2) promoter, and consisting of a direct repeat of the motif 5'-GGTCA-3' separated by three nucleotides, was found within this restriction fragment. Mutation of these 5'-GGTCA-3' motifs to GGAGC and GGGGC abolished RA-inducible transcription whereas a mutation to a direct repeat of the GTTCA motif found in the RARE of the RAR-beta 2 promoter resulted in enhanced inducibility. Oligonucleotides containing the direct repeat of the GGTCA motif were able to confer RA-dependent transcriptional enhancement to the herpes simplex thymidine kinase promoter, as well as to bind directly all three retinoic acid receptors (RARs) alpha, beta and gamma, as determined by gel retardation/shift assays. The control of CRBPI gene transcription by RA-RAR complexes interacting with the RARE characterized here may correspond to a feedback mechanism important in regulating retinoid metabolism and action.
Amino Acid Sequence↗
Cigarette smoking and employment status.
The smoking habits and health knowledge of the unemployed and the full-time workers were investigated in a cross-sectional study of over 10,000 men and women throughout Scotland. For both sexes (age range 40-59 years), the proportion of current smokers and ever smokers was found to be considerably higher among the unemployed. Only a small part of the difference could be explained by standardisation for social class. The unemployed smokers had began to smoke at an earlier age, with significantly more smoking whilst still at school. Amongst current smokers, the unemployed males reported smoking fewer cigarettes a day, whereas unemployed women smoked more than their full-time counterparts. The reported levels were confirmed by the biochemical measures of smoking; serum thiocyanate and expired air carbon monoxide levels. In contrast to their differences in smoking habit, the two groups were very similar in their knowledge of the hazards of smoking. Smoking habits among the unemployed reflect a complex interaction of financial and both current and previous social factors. Such relationships present a particular challenge to health promotion campaigns.
Adult↗
Smoking characteristics and inhalation biochemistry in the Scottish population.
Data from a cross-sectional random population sample of 10,359 middle-aged Scottish men and women are used to investigate the relationships between self-reported tobacco consumption and three biochemical markers of tobacco inhalation: expired air carbon monoxide (CO), serum thiocyanate and serum cotinine. These data represent one of the largest samples of these biochemical markers yet analysed. The results show that, for each sex, the biochemical markers are highly correlated for smokers and for the entire sample of mixed smokers and non-smokers. CO is the preferred biochemical marker, in such groups, because it is the cheapest, is non-invasive and gives virtually instantaneous results. Self-reported daily cigarette consumption also correlates well with each of these biochemical markers, and so it appears that people are, in the context of population studies, mainly truthful about their smoking. The relationships with self-reported cigarette consumption are curvilinear with apparent levelling out of the gradient at around 25 cigarettes/day for cotinine and thiocyanate and at greater than 40 cigarettes/day for CO. Sex differences are small, although thiocyanate is generally higher and cotinine generally lower in women with the same self-reported cigarette consumption as men. Amongst non-smokers, only cotinine is able to discriminate between self-reported levels of exposure to passive smoking. CO and thiocyanate are not suitable for measuring low levels of smoke inhalation, such as found in passive smokers.
Adult↗
Localization of retinal photoisomerase in the compound eye of the honeybee.
The distribution of honeybee retinal photoisomerase, a soluble light-requiring enzyme that stereospecifically forms 11-cis retinal, was investigated by immunoelectron microscopy and by HPLC. Immunolocalization with polyclonal antibodies shows that the highest concentration of retinal photoisomerase is located in the proximal portion of the primary pigment cells in large aggregates (approximately 2 microns diameter). Photoisomerase is also located in the peripheral portion of the photoreceptor cells, laterally displaced from the rhabdom, but in much lower concentration. Because of the larger volume of the photoreceptor cells, about half of the total immunoreactivity is associated with the primary pigment cells. Dissection of the eye with the subsequent use of HPLC to assay for photoisomerase activity showed that most of the photoisomerase activity is associated with tissues near the cornea. The same tissue also supports the reduction of 11-cis retinal to 11-cis retinol. These biochemical findings are consistent with the immunolocalization of retinal photoisomerase to the high-concentration aggregates in the primary pigment cells that surround the crystalline cones. The major synthesis of 11-cis retinol therefore takes place in the primary pigment cells, and the retinoid must be moved into the photoreceptor cells to be available to newly synthesized opsin. The immunoreactivity of the photoreceptor cells appears to reflect the presence of some isomerase without an attached retinoid chromophore.
Animals↗
Nutrient intakes of different social-class groups: results from the Scottish Heart Health Study (SHHS).
Food frequency questionnaire and socio-demographic data were collected from over 10,000 Scottish men and women aged 40-59 years in a cross-sectional study of coronary heart disease (CHD) risk factors. Dietary intake, including the antioxidant vitamins C and E and beta-carotene, was assessed for different socio-economic groups. Trends in nutrient intakes were found with social-class (occupational) groups I-V. The non-manual-manual distinctions were clear even after standardizing for serum cotinine, and alternative classification by housing tenure and level of education did not confound the social-class effect. Total energy intake was significantly higher in the manual (men 10,363 KJ, women 7507 KJ) than in the non-manual (men 9156 KJ, women 7169 KJ) groups, and all nutrient amounts except for vitamin C, vitamin E, beta-carotene and fibre were significantly higher in the manual than the non-manual groups. Alcohol intake was lower in manual women, but higher in manual men compared with their respective non-manual groups. Sex and social-class differences were maintained after adjusting for total energy. Women in general, and manual women in particular, had the highest percentage energy from total fat (40.2) and saturated fat (18.2), while the percentage energy from polyunsaturated fat was lower in men than women, and lowest in manual men (4.4). The polyunsaturated:saturated fat (P:S) ratios were, for non-manual and manual men 0.32 and 0.31, and for non-manual and manual women 0.31 and 0.28. Fibre and antioxidant vitamin intakes, when expressed as nutrient densities, were lower in men than women, and lowest in manual men. Overall, men and women in manual occupations had a poorer-quality diet than did those in non-manual occupations. The coincident low P:S ratios and low antioxidant vitamin intakes in manual groups may contribute to an increased risk of CHD. Thus, the findings are compatible with the view that poor diet may be a contributory factor to the higher mortality rates for CHD which occur in the lower socio-economic groups.
Adult↗
Antioxidant vitamin intakes assessed using a food-frequency questionnaire: correlation with biochemical status in smokers and non-smokers.
The increasing interest in the possible role of antioxidant vitamins in many disease states means that methods of assessing vitamin intakes which are suitable for large-scale investigations are now required. The suitability of the food-frequency questionnaire, which was developed by the Medical Research Council - Cardiff Group, for determining dietary intake of antioxidant vitamins in epidemiological studies was investigated in 196 Scottish men. The validity of the dietary data was assessed by comparison with serum vitamin concentrations, and separate analyses were performed for current smokers and non-smokers. The results showed that total energy intake and the percentage of energy derived from sugar were higher in smokers, and that both dietary and serum values of vitamin C, beta-carotene and vitamin E were lower in smokers than non-smokers. After adjustment for serum lipids, energy intake and body mass index, correlation coefficients between dietary and serum vitamins C and E were similar for smokers (r 0.555 and 0.25 respectively) and non-smokers (r 0.58 and 0.32 respectively). Correlation between dietary and serum carotenes was reduced from 0.28 in non-smokers to 0.09 in smokers and correlations for retinol and total vitamin A were weakly significant only for non-smokers. The food-frequency questionnaire assigned greater than 70% of subjects correctly into the upper or lower plus adjacent tertiles of serum vitamin values, with the exception of beta-carotene and total vitamin A for smokers. Thus, the food-frequency questionnaire appeared to be an adequate tool for assigning individuals into tertiles of serum antioxidant vitamins with the main exception of beta-carotene for smokers. Marked differences do occur between the vitamins and between the smoking groups which may reflect reduced accuracy of reporting on the food-frequency questionnaire or differential absorption and metabolism of the vitamins.
Adult↗
The role of retinal photoisomerase in the visual cycle of the honeybee.
The compound eye of the honeybee has previously been shown to contain a soluble retinal photoisomerase which, in vitro, is able to catalyze stereospecifically the photoconversion of all-trans retinal to 11-cis retinal. In this study we combine in vivo and in vitro techniques to demonstrate how the retinal photoisomerase is involved in the visual cycle, creating 11-cis retinal for the generation of visual pigment. Honeybees have approximately 2.5 pmol/eye of retinal associated with visual pigments, but larger amounts (4-12 pmol/eye) of both retinal and retinol bound to soluble proteins. When bees are dark adapted for 24 h or longer, greater than 80% of the endogenous retinal, mostly in the all-trans configuration, is associated with the retinal photoisomerase. On exposure to blue light the retinal is isomerized to 11-cis, which makes it available to an alcohol dehydrogenase. Most of it is then reduced to 11-cis retinol. The retinol is not esterified and remains associated with a soluble protein, serving as a reservoir of 11-cis retinoid available for renewal of visual pigment. Alternatively, 11-cis retinal can be transferred directly to opsin to regenerate rhodopsin, as shown by synthesis of rhodopsin in bleached frog rod outer segments. This retinaldehyde cycle from the honeybee is the third to be described. It appears very similar to the system in another group of arthropods, flies, and differs from the isomerization processes in vertebrates and cephalopod mollusks.
Adaptation, Ocular↗
Dietary and non-dietary predictors of serum total and HDL-cholesterol in men and women: results from the Scottish Heart Health Study.
UNLABELLED: An analysis of the associations between dietary and non-dietary variables and serum total cholesterol (Total-C) and high density lipoprotein cholesterol (HDL-C) was performed using data from the Scottish Heart Health Study--a cross-sectional survey of men (n = 5123) and women (n = 5236), aged 40-59. Subjects completed a questionnaire which provided health, socio-demographic and food frequency data. Nutrient intakes were calculated from UK food composition tables using standard portion sizes. For men, the significant independent dietary predictors of Total-C, after adjustment for all the other dietary variables, were saturated fat and cereal fibre, and after adjustment for the non-dietary variables, were cereal fibre, saturated fat and cholesterol. For women, intake of vegetable fibre, white fish and beta-carotene were significant independent predictors of Total-C after adjustment for all the other dietary variables. Only beta-carotene remained significant after adjustment for all the non-dietary variables. Alcohol intake and body mass index were respectively the strongest positive and negative predictors of HDL-C for both sexes. IN CONCLUSION: (1) certain dietary factors may affect serum cholesterol levels differently for men and women; (2) a possible role for the antioxidant vitamins and fibre in the prediction of serum cholesterol, may be indicated, in addition to the 'classical' role of dietary cholesterol and saturated fat and (3) confounding between the social and dietary variables does occur, and confirms the need for multiple adjustments in studies of this nature.
Adult↗
Bias from missing values: sex differences in implication of failed venepuncture for the Scottish Heart Health Study.
Missing values are common in epidemiological data, and yet their possible effect on the results of the investigation is seldom quantified despite the fact that they are a likely source of bias. This paper describes a simple method, based on odds ratios, for assessing whether missing values are likely to cause bias, and for quantifying the magnitude of any such bias. The method is applied to the Scottish Heart Health Study, a study of risk factors for coronary heart disease amongst 10,359 men and women. It is found that, although no bias is apparent in the male subjects, females with missing blood samples are twice as likely to have a history of myocardial infarction than other women. Missing blood samples are shown to be associated with increased body mass index and difficult peripheral veins. The bias caused by the missing female blood samples is considerable, with estimated errors of between 4% and 12% in the mean values of total cholesterol, HDL-cholesterol, triglycerides, creatinine, uric acid and fibrinogen.
Adult↗
An evaluation with piglets of bovine milk, hydrolyzed bovine milk, and isolated soybean proteins included in infant milk formulas. II. Stomach-emptying rate and the postprandial change in gastric pH and milk-clotting enzyme activity.
The piglet was used as a model for the human infant to determine the effect of the protein source of a milk formula on stomach-emptying rate and the postprandial changes in gastric pH and milk-clotting enzyme activity. Three liquid milk formulas containing either intact bovine milk protein, hydrolyzed bovine milk protein, or isolated soybean protein as the sole source of dietary protein were given to five 37-day-old piglets that had undergone surgery for the preparation of a simple gastric fistula. At set times after commencement of a meal, the stomach contents were removed via a gastric cannula and weighed; then pH and milk-clotting enzyme activity were determined. The isolated soybean protein-based formula tended to empty from the stomach more slowly than did the bovine milk-based formulas. Maximum difference (p less than 0.05) was found at 3 h postfeeding, where 30% of the ingested soybean formula dry matter remained in the stomach; comparable values for the intact bovine milk-based formula and hydrolysate were 22 and 12%, respectively. The type of protein did not significantly (p greater than 0.05) affect the postprandial change in gastric pH or gastric milk-clotting enzyme activity. Gastric pH increased sharply after feeding, from pH 1.5 at 0 h to pH 5.2 at 1 h, and then fell gradually over the following 4 h to pH 1.84.
Analysis of Variance↗
Cigarette tar content and symptoms of chronic bronchitis: results of the Scottish Heart Health Study.
STUDY OBJECTIVE: The aim was to determine if there was a relationship between cigarette tar yield and rates of chronic cough and chronic phlegm. SETTING: 22 districts across Scotland were used for the Scottish Heart Health Study (SHHS) which was conducted between 1984 and 1986 and from which the data for this analysis were obtained. SUBJECTS: 10,359 men and women aged 40-59 years were studied. Of these, 2801 current cigarette smokers whose brand of cigarette smoked was known were selected. MEASUREMENTS AND MAIN RESULTS: Data on self reported smoking habits and prevalence of chronic cough and chronic phlegm were obtained from the SHHS. Tar yield was divided into three groups: low (less than or equal to 12 mg/cigarette); middle (13-14 mg/cigarette); high (greater than or equal to 15 mg/cigarette). The average tar yield consumed per person was 13.2 mg/cigarette. Women in the middle and high tar groups had smoked for longer and had significantly higher breath carbon monoxide levels, serum thiocyanate levels, serum cotinine levels, and daily cigarette consumption than the women in the low tar group. This pattern was not seen in men for any of these five smoking variables. Rates of chronic cough and chronic phlegm were higher with higher tar yield of cigarettes smoked for women (low tar v high tar: p less than 0.001) but not for men. Daily cigarette consumption and the number of years of smoking were the most significant risk factors for chronic cough and chronic phlegm for both men and women. Tar was still a significant risk factor (p less than 0.05) for women after controlling for these two risk factors and social class. CONCLUSIONS: Both sexes show strong effects of daily cigarette consumption and years of smoking on respiratory symptoms; women show an additional effect of cigarette tar content while men do not. The spread of tar yield in both sexes was small but there were more women on low tar cigarettes and this may have enabled a weak effect of tar to be seen better in them. On the other hand, tar level in women was confounded with other factors. Statistical methods of controlling for this may not have removed this confounding completely.
Adult↗
The impact of quitting smoking on symptoms of chronic bronchitis: results of the Scottish Heart Health Study.
Scotland has high rates of death from diseases of the respiratory system and high rates of smoking, especially among women. Data on self reported smoking and prevalence of chronic cough and chronic phlegm among 10,359 men and women aged 40-59 years were obtained from the Scottish Heart Health Study. Overall, current cigarette smokers had rates of chronic cough and chronic phlegm four to five times those of never smokers after standardisation for age (32.3% v 6.5% for men and 24% v 5.5% for women for chronic cough; 31% v 8.3% for men and 21% v 5.5% for women for chronic phlegm). Ex-smokers' symptom rates were a little above those of never smokers and were significant for chronic cough among women and chronic phlegm among men. Men had higher symptom rates than women and this was true for smokers, ex-smokers, and never smokers. The higher rates among men could not be explained by higher cotinine concentrations. Tests to detect "deceivers" among ex-smokers and never smokers using biochemical validation suggested that 87 (1.5%) respondents were in fact smoking; they were excluded from analyses. There were substantially lower rates of chronic cough and chronic phlegm within a year of stopping smoking, and two to four years after stopping 89-99% of the difference between current smokers and never smokers was accounted for (99% and 93% for men and women with chronic cough, 96% and 89% for men and women with chronic phlegm). Even 10 years after stopping, rates of symptoms among ex-smokers remained a little above those of never smokers (except for women with chronic phlegm), though these differences were not statistically significant. Former heavy smokers continued to have rates of chronic cough and chronic phlegm that were higher than those of former light and moderate smokers (though not significantly so). These are cross sectional data, but they emphasise the importance for chronic bronchitis symptoms of giving up cigarette smoking, though the amount previously smoked continues to exert a small influence.
Adult↗
A screening and alerting questionnaire for parkinsonism.
A self-administered eight-symptom questionnaire on parkinsonism was completed by 35 patients known to have parkinsonism and 88 controls independently selected by a local general practice. The presence of shaking and difficulty opening things/doing small buttons were the commonest positive responses among the cases (27/35). While a shuffling walk and difficulty turning in bed were the least frequent positive responses among the cases, they were also the two questions least likely to be positive in the control group. The question on shaking was the most discriminating between cases and controls. When the question on a shuffling walk was added, a positive answer to questions correctly identified 91% of cases and 92% of controls. These questions can form the basis of an alerting/screening questionnaire for parkinsonism and could be useful in screening smaller targeted populations such as a general practice list.
Aged↗
Control of blood pressure in Scotland: the rule of halves.
OBJECTIVE: Audit of detection, treatment, and control of hypertension in adults in Scotland. DESIGN: Cross sectional survey with random population sampling. SETTING: General practice centres in 22 Scottish districts. SUBJECTS: 5123 Men and 5236 women aged 40-59 in the Scottish heart health study, randomly selected from 22 districts throughout Scotland, of whom 1262 men and 1061 women had hypertension (defined as receiving antihypertensive treatment or with blood pressure above defined cut off points). MAIN OUTCOME MEASURE: Hypertension (assessed by standardised recording, questionnaire on diagnosis, and antihypertensive drug treatment) according to criteria of the World Health Organisation (receiving antihypertensive treatment or blood pressure greater than or equal to 160/95 mm Hg, or both) and to modified criteria of the British Hypertension Society. RESULTS: In half the men with blood pressure greater than or equal to 160/95 mm Hg hypertension was undetected (670/1262, 53%), in half of those in whom it had been detected it was untreated (250/592, 42%), and in half of those receiving treatment it was not controlled (172/342, 50%). In women the numbers were: 486/1061, 46%; 188/575, 33%; and 155/387, 40% respectively. Assessment of blood pressure according to the British Hypertension Society's recommendations showed an improvement, but in only a quarter of men and 42% of women was hypertension detected and treated satisfactorily (142/561, 215/514 respectively). IMPLICATIONS: The detection and control of hypertension in Scotland is unsatisfactory, affecting management of this and other conditions, such as high blood cholesterol concentration, whose measurement is opportunistic and selective and depends on recognition of other risk factors.
Adult↗
Phyletic aspects of the distribution of 3-hydroxyretinal in the class Insecta.
The distribution of 3-hydroxyretinal (R3), a recently discovered retinoid used as the visual pigment chromophore in some insects, was investigated in the class Insecta using HPLC technology. We studied 138 species in 24 orders, sampling from a wide range of taxonomic groups as well as varied habitats. In addition to groups already known to have R3, we find this retinoid in Hemiptera (suborder Heteroptera), Plecoptera, Megaloptera, and Hymenoptera. We also find retinal (R1) in Hemiptera (suborder Homoptera), Mecoptera, and Trichoptera, groups previously thought to have only R3. The pattern of R3 occurrence indicates that this retinoid cannot be considered a phylogenetic marker, having a scattered distribution in the class Insecta as well as within some orders of insects. Several environmental factors that might influence the selection of chromophore have been considered, but none correlates with its distribution. The evolutionary reasons for the pattern of occurrence of R3 therefore remain unknown.
Animals↗