Biomedical subjects

C Heath

Publications and source records attributed to C Heath.

At least 19 recordsLinked to original sources

PubMed1999

Prospective study of intentional weight loss and mortality in overweight white men aged 40-64 years.

Although 25% of US men indicate that they are trying to lose weight, the association between intentional weight loss and longevity in men is unknown. The authors analyzed prospective data from 49,337 overweight (initial body mass index > or =27) white men aged 40-64 years who, in 1959-1960, answered questions on weight change direction, amount, time interval, and intent. Vital status was determined in 1972. Proportional hazards regression estimated mortality rate ratios for men who intentionally lost weight compared with men with no weight change. Analyses were stratified by health status and adjusted for age, initial body mass index, smoking status, alcohol intake, education, physical activity, health history, and physical symptoms. Among men with no reported health conditions (n = 36,280), intentional weight loss was not associated with total, cardiovascular (CVD), or cancer mortality, but diabetes-associated mortality was increased 48% (95% confidence interval (CI) -7% to +133%) among those who lost 20 pounds (9.1 kg) or more; this increase was largely related to non-CVD mortality. Among men with reported health conditions (n = 13,057), intentional weight loss had no association with total or CVD mortality, but cancer mortality increased 25% (95% confidence interval -4% to +63%) among those who lost 20 pounds or more. Diabetes-associated mortality was reduced 32% (95% confidence interval -52% to -5%) among those who lost less than 20 pounds and 36% (95% confidence interval -49% to -20%) among those who lost more than 20 pounds. These results and those from our earlier study in women (Williamson et al., Am J Epidemiol 1995;141:1128-41) suggest that intentional weight loss may reduce the risk of dying from diabetes, but not from CVD. In observational studies, however, it is difficult to separate intentional weight loss from unintentional weight loss due to undiagnosed, underlying disease. Well-designed observational studies, as well as randomized controlled trials, are needed to determine whether intentional weight loss reduces CVD mortality.

Adult↗

PubMed1999

Goals as reference points.

We argue that goals serve as reference points and alter outcomes in a manner consistent with the value function of Prospect Theory (Kahneman & Tversky, 1979; Tversky & Kahneman, 1992). We present new evidence that goals inherit the properties of the value function-not only a reference point, but also loss aversion and diminishing sensitivity. We also use the value function to explain previous empirical results in the goal literature on affect, effort, persistence, and performance.

Cognition↗

PubMed1999

On the Social Psychology of Agency Relationships: Lay Theories of Motivation Overemphasize Extrinsic Incentives.

Three laboratory studies and one field study show that people generally hold lay theories which contain an extrinsic incentives bias-people predict that others are more motivated than themselves by extrinsic incentives (job security, pay) and less motivated by intrinsic incentives (learning new things). The extrinsic incentives bias can be separated from a self-serving bias and it provides an empirical counterexample to the traditional actor-observer effect in social psychology (although its theoretical explanation is similar). This kind of bias may hinder organizations from organizing because people who act as principals may use improper lay theories to offer inappropriate deals to agents. Copyright 1999 Academic Press.

Journal Article↗

PubMed1998

NF-kappaB mediated transcriptional activation is enhanced by the architectural factor HMGI-C.

High mobility group I proteins (HMGI, HMGY and HMGI-C) are a family of low molecular mass non-histone nuclear proteins which constitute an important component of the active chromatin structure. Two members of this family, HMGI and HMGY, have been demonstrated to contribute to the transcriptional regulation of several promoters by interacting with the DNA and with different transcription factors. On the contrary, very little is known about the third member, HMGI-C, which plays an important role during embryonic growth and in the process of cell transformation, its gene being rearranged in a large number of mesenchimal tumors. In this paper we show for the first time that HMGI-C is also able to function as architectural factor, enhancing the activity of a transcription factor, NF-kappaB, through the PRDII element of the beta-interferon enhancer. Moreover we show that this enhancement is absolutely dependent on the binding of HMGI-C to its target sequence. The demonstration that HMGI-C is able to modulate transcription is thus an important initial step in the identification of genes regulated by this factor.

3T3 Cells↗

PubMed1998

Viability of Chlamydia trachomatis in fallopian tubes of patients with ectopic pregnancy.

OBJECTIVE: To use standard molecular methods to define the prevalence and metabolic characteristics of Chlamydia trachomatis during infection of fallopian tubes in women with ectopic pregnancies. DESIGN: Polymerase chain reaction (PCR)- and reverse transcription-PCR (RT-PCR)-based assessment of presence of chlamydial DNA and various RNA species in fallopian tube biopsy samples. SETTING: Hospital and molecular genetics laboratory. PATIENTS: Ten women of varying ages, each presenting with ectopic pregnancy. MAIN OUTCOME MEASURE(S): Positive signal in specific chlamydia-directed PCR and RT-PCR assays. RESULT(S): Nucleic acid preparations from 7 of the 10 fallopian tube patient samples were PCR-positive for C. trachomatis DNA. Each of the 7 PCR-positive samples also showed the presence of several transcripts from the bacterium, including primary transcripts from the ribosomal RNA operons. CONCLUSION(S): A higher proportion of ectopic pregnancies than was believed previously may be attributable to infection of the fallopian tubes by C. trachomatis. The presence of various chlamydial RNA molecules suggests that viable, metabolically active bacteria were present in fallopian tubes of the patients studied.

Adult↗

PubMed1997

A structure/function analysis of Rat7p/Nup159p, an essential nucleoporin of Saccharomyces cerevisiae.

Rat7p/Nup159p is an essential nucleoporin of Sac-charomyces cerevisiae originally isolated in a genetic screen designed to identify yeast temperature-sensitive mutants defective in mRNA export. Here we describe a detailed structural-functional analysis of Rat7p/Nup159p. The mutation in the rat7-1 ts allele, isolated in the original genetic screen, was found to be a single base pair change that created a stop codon approximately 100 amino acids upstream of the actual stop codon of this 1,460 amino acid polypeptide, thus eliminating one of the two predicted coiled-coil regions located near the carboxyl terminus of the protein. These coiled-coil regions are essential since an allele lacking both coiled-coil regions was unable to support growth under any conditions. In contrast, no other region of the protein was absolutely required. The SAFG/PSFG repeat region in the central third of the protein was completely dispensable for growth at temperatures between 16 degrees C and 37 degrees C and cells expressing this mutant allele were indistinguishable from wild type. Deletion of the amino-terminal third of the protein, upstream from the repeat region, or the portion between the repeat region and the coiled-coils resulted in temperature-sensitivity, but the two alleles showed distinct phenotypes with respect to the behavior of nuclear pore complexes (NPCs). Taken together, our data suggest that Rat7p/Nup159p is anchored within the NPC through its coiled-coil region and adjacent sequences. In addition, we postulate that the N-terminal third of Rat7p/Nup159p plays an important role in mRNA export.

Alleles↗

PubMed1996

Environmental tobacco smoke and coronary heart disease in the American Cancer Society CPS-II cohort.

BACKGROUND: Thirteen of 14 epidemiological studies have shown an increased risk of approximately 20% for coronary heart disease (CHD) for never-smokers exposed to environmental tobacco smoke (ETS), but this association remains controversial. If true, ETS might account for an estimated 35,000 to 40,000 heart disease deaths per year in the United States. METHODS AND RESULTS: We have conducted the largest study to date, a prospective study of 353,180 female and 126,500 male never-smokers enrolled in 1982 in the American Cancer Society's Cancer Prevention Study II and followed through 1989. Analyses focused on subcohorts of 309,599 married pairs and of 135,237 subjects concordant for self-reported exposure and exposure reported by each one's spouse. More than 2800 CHD deaths (ICD 410-414) occurred among married pairs; 10% of married men and 28% of married women were married to currently smoking spouses, while 10% and 32%, respectively, were married to former smokers. After controlling for many cardiovascular risk factors, we found 22% higher CHD mortality (rate ratio, 1.22; 95% CI, 1.07 to 1.40) among never-smoking men married to currently smoking wives compared with those married to wives who had never smoked. The corresponding rate ratio for women was 1.10 (0.96 to 1.27). Never-smokers living with former smokers showed no increased risk. When analyses were restricted to subjects whose ETS exposure was classified via both their own self-report and a spouse's report, the rate ratio was 1.23 (1.03 to 1.47) for currently exposed men and 1.19 (0.97 to 1.45) for women. CONCLUSIONS: Results are consistent with prior reports that never-smokers currently exposed to ETS have about 20% higher CHD death rates. However, our data do not show consistent dose-response trends and are possibly subject to confounding by unmeasured risk factors.

Adult↗

PubMed1996

Do People Prefer to Pass Along Good or Bad News? Valence and Relevance of News as Predictors of Transmission Propensity

Anecdotal evidence seems to indicate that exaggeratedly bad news may propagate in the marketplace of ideas. Three studies investigate whether people prefer to pass along pieces of bad news or good news that are equated for "surprisingness." People typically prefer to pass along central rather than extreme information (i.e., news that is less surprising rather than more surprising). However, when confronted with extreme information, the results support a preference for congruence, that is, people prefer to pass along news that is congruent with the emotional valence of the domain in question. This means that in emotionally negative domains, contrary to some theoretical predictions, people are willing to pass along bad news even when it is exaggeratedly bad. At the same time, however, people transmit exaggeratedly good news in emotionally positive domains. The general discussion indicates how these results may inform research on word of mouth for consumer products and social relations in organizations.

Journal Article↗

PubMed1996

Mental Depreciation and Marginal Decision Making

We propose that individuals practice "mental depreciation," that is, they implicitly spread the fixed costs of their expenses over time or use. Two studies explore how people spread fixed costs on durable goods. A third study shows that depreciation can lead to two distinct errors in marginal decisions: First, people sometimes invest too much effort to get their money's worth from an expense (e.g., they may use a product a lot to spread the fixed expense across more uses). Second, people sometimes invest too little effort to get their money's worth: When people add a portion of the fixed cost to the current costs, their perceived marginal (i.e., incremental) costs exceed their true marginal costs. In response, they may stop investing because their perceived costs surpass the marginal benefits they are receiving. The latter effect is supported by two field studies that explore real board plan decisions by university students.

Journal Article↗

PubMed1996

The evaluation gap in performance perceptions: illusory perceptions of groups and individuals.

Four laboratory studies documented systematic performance illusions for individuals and group members. After completing a task, most individuals typically rank their performance below the median (a negative performance illusion) and most group members rank their group performance above the median (a positive performance illusion). This evaluation gap surfaced in all studies; group members consistently assign their group a higher rank than individuals assign themselves. This gap contradicts a number of theories assuming that group biases merely extend individual biases.

Efficiency, Organizational↗

PubMed1996

Mortality from smoking worldwide.

Estimates are made of the numbers and proportions of deaths attributable to smoking in 44 developed countries in 1990. In developed countries as a whole, tobacco was responsible for 24% of all male deaths and 7% of all female deaths, rising to over 40% in men in some former socialist economies and 17% in women in the USA. The average loss of life for all cigarette smokers was about 8 years and for those whose deaths were attributable to tobacco about 16 years. Trends in mortality attributable to tobacco differed between countries. In some the mortality in middle age (35-69 years) had decreased by half in men since 1965; in others it was continuing to increase. In women, the proportion was mostly increasing, almost universally in old age. Mortality not attributable to smoking decreased since 1955 in all OECD (Organization for European Collaboration and Development) countries, by up to 60% in men and more in women. No precise estimate can be made of the number of deaths attributable to smoking in undeveloped countries, but the prevalence of smoking suggests that it will be large. In the world as a whole, some 3 million deaths a year are estimated to be attributable to smoking, rising to 10 million a year in 30-40 years' time.

Adolescent↗

PubMed1995

Prospective study of intentional weight loss and mortality in never-smoking overweight US white women aged 40-64 years.

Although 40% of US women indicate they are currently trying to lose weight, the association between intentional weight loss and longevity is unknown. The authors analyzed prospective data from 43,457 overweight, never-smoking US white women aged 40-64 years who in 1959-1960 completed a questionnaire that included questions on weight change direction, amount, time interval, and intentionality. Vital status was determined in 1972. Proportional hazards regression was used to estimate mortality rate ratios for women who intentionally lost weight compared with women who had no change in weight. Women who died within the first 3 years of follow-up were excluded. Analyses were stratified by preexisting illness and adjusted for age, beginning body mass index, alcohol intake, education, physical activity, and health conditions. In women with obesity-related health conditions (n = 15,069), intentional weight loss of any amount was associated with a 20% reduction in all-cause mortality, primarily due to a 40-50% reduction in mortality from obesity-related cancers; diabetes-associated mortality was also reduced by 30-40% in those who intentionally lost weight. In women with no preexisting illness (n = 28,388), intentional weight loss of > or = 20 lb (> or = 9.1 kg) that occurred within the previous year was associated with about a 25% reduction in all-cause, cardiovascular, and cancer mortality; however, loss of < 20 lb (< 9.1 kg) or loss that occurred over an interval of > or = 1 year was generally associated with small to modest increases in mortality. The association between intentional weight loss and longevity in middle-aged overweight women appears to depend on their health status. Intentional weight loss among women with obesity-related conditions is generally associated with decreased premature mortality, whereas among women with no preexisting illness, the association is equivocal.

Adult↗

PubMed1995

How do desk-top computers affect the doctor-patient interaction?

General practice consultations were video-recorded before and after the introduction of a desk-top computer system into the practice. The recordings were analysed by detailed qualitative scrutiny of tape and transcripts (conversation analysis) to discover regular patterns of interaction. This analysis confirmed that the introduction of computers into the consultation had a significant impact on the communication between patient and doctor. In particular, we found that computer technology has had an impact on the practitioners' conduct and on the disclosure of information by the patient. The analysis also points to some recommendations both for training general practitioners in the use of computerized systems in the consultation, and for the (re)design of the technologies themselves.

Computer Terminals↗

PubMed1993

Do family physicians treat obese patients?

BACKGROUND: The purpose of this study was to characterize what patient and physician factors increase the likelihood of physicians counseling weight loss in their overweight patients. METHODS: A retrospective chart survey of 418 outpatient charts from 50 family medicine residents and faculty was conducted. RESULTS: Of the 267 patients who were overweight based on a body mass index score of more than 27, only 29.6% had been instructed to lose weight. Overweight patients with hypertension, diabetes, hypercholesterolemia, or coronary artery disease were instructed to lose weight 32.9% of the time. Patient age or sex and physician age, sex, or level of training did not affect the frequency of treatment. CONCLUSION: Physicians need to be more aggressive in their counseling of overweight patients.

Adult↗

PubMed1992

Mortality from tobacco in developed countries: indirect estimation from national vital statistics.

Prolonged cigarette smoking causes even more deaths from other diseases than from lung cancer. In developed countries, the absolute age-sex-specific lung cancer rates can be used to indicate the approximate proportions due to tobacco of deaths not only from lung cancer itself but also, indirectly, from vascular disease and from various other categories of disease. Even in the absence of direct information on smoking histories, therefore, national mortality from tobacco can be estimated approximately just from the disease mortality statistics that are available from all major developed countries for about 1985 (and for 1975 and so, by extrapolation, for 1995). The relation between the absolute excess of lung cancer and the proportional excess of other diseases can only be approximate, and so as not to overestimate the effects of tobacco it has been taken to be only half that suggested by a recent large prospective study of smoking and death among one million Americans. Application of such methods indicates that, in developed countries alone, annual deaths from smoking number about 0.9 million in 1965, 1.3 million in 1975, 1.7 million in 1985, and 2.1 million in 1995 (and hence about 21 million in the decade 1990-99: 5-6 million European Community, 5-6 million USA, 5 million former USSR, 3 million Eastern and other Europe, and 2 million elsewhere, [ie, Australia, Canada, Japan, and New Zealand]). More than half these deaths will be at 35-69 years of age: during the 1990s tobacco will in developed countries cause about 30% of all deaths at 35-69 (making it the largest single cause of premature death) plus about 14% of all at older ages. Those killed at older ages are on average already almost 80 years old, however, and might have died soon anyway, but those killed by tobacco at 35-69 lose an average of about 23 years of life. At present just under 20% of all deaths in developed countries are attributed to tobacco, but this percentage is still rising, suggesting that on current smoking patterns just over 20% of those now living in developed countries will eventually be killed by tobacco (ie, about a quarter of a billion, out of a current total population of just under one and a quarter billion).

Adult↗

PubMed1990

Methods for increasing monoclonal antibody production in suspension and entrapped cell cultures: biochemical and flow cytometric analysis as a function of medium serum content.

The growth and antibody production of the SP2/0-derived hybridoma HB124 (ATCC) grown in media containing varying amounts of fetal bovine serum (FBS) were monitored using biochemical and flow cytometric methods. Hybridomas grown in 100 ml spinner flasks with RPMI-1640 containing varying amounts of serum demonstrated that cell growth, viability and IgG production show significant changes when serum content is decreased from 10.0 to 5.5 to 1.0 and 0.5%. A longer lag phase resulted when the lower serum content media were used. Cellular rates of glucose uptake showed a significant increase as serum levels were lowered. Similarly, exponential phase IgG production rates increased as the amount of serum was decreased, probably as a result of the decreased rate of exponential growth. Flow cytometric analysis showed a similar increase in cellular IgG content as medium serum levels declined. In contrast, the maximum IgG concentrations were found in flasks containing 1% FBS or above with the lowest concentration in the 0.5% FBS flask being due to the lower numbers of viable cells. Cells grown in microporous hollow fiber reactors were fed with medium containing serum which was decreased stepwise with time. Decreasing medium serum content stepwise from 10 to 2.5% resulted in increased antibody production. However, complete removal of serum from the medium resulted in a significant drop in antibody productivity. Cumulative antibody production was equivalent for cells grown entirely in medium containing 10% FBS and for those which experienced a drop to 2.5% FBS. To compare a defined serum-free medium preparation with medium containing 10% FBS, cells were again grown in batch suspension culture and analyzed. The growth rates were similar but there was a significant difference in IgG production rates. The serum-free culture exhibited both higher cellular production rates and higher IgG concentrations. These results indicate that decreasing medium serum content can adversely affect antibody yield because of lower cell viabilities, not because of lower production rates. Use of a defined serum-free medium, as done in this study, results in higher yields because of a higher IgG production rate as well as good cell growth and viability.

Animals↗

PubMed1990

Diagnosis of patellofemoral pain syndrome.

This syndrome, also known as chondromalacia patellae, is characterised by pain and crepitus around the patella during activities that require flexion of the knee under loading, for example, climbing stairs.

Femur↗

PubMed1987

What is a good GP?

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Communication↗