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PubMed1996

The worksite environment as a cue to smoking reduction.

With a modified version of the Health Belief Model as the conceptual framework, the hypothesis that exposure to a worksite health-promoting environment acted as a cue to smoking reduction among 310 smokers was tested with a quasi-experimental design. Using path analysis (LISREL), the total effects on posttest smoking were decomposed. Results showed exposure to the health-promoting environment had statistically significant direct and indirect effects on posttest smoking. The indirect effect was through the posttest perceived barriers variable. The LISREL model explained 74% of the variance in smoking reduction and fit the data satisfactorily. The importance of developing the worksite as a health-promoting force is discussed.

Adult↗

PubMed1994

Early detection of cancer. Psychologic and social dimensions.

Major strides in early detection research can be attributed to social and behavioral research. Social scientists have been involved in research determining the epidemiologic basis of and the cost-effectiveness of screening for asymptomatic disease. The availability of well accepted screening tests has been a barrier to early detection research, especially in the area of men's health. Early detection research has focused on the individual and system levels. Theoretical models are being adapted for early detection from smoking research and are a strength of current work. These models explain why people participate in early detection and how behavior change can occur. In studying system barriers to early detection, intervention efforts have been focused in the community and in the medical care delivery system. Methodologic issues are beginning to emerge, including measuring of program outcomes, and the appropriate research designs for community studies. Except for immigrant populations, initial screening rates are high, and the periodicity of screening becomes the outcome of choice. Some of these problems are the direct result of the success of research and public education efforts to increase cancer screening. The following are priorities for the next decade: theory driven research on behavior change and on interventions; the social determinants of physicians' participation in screening; process evaluation to relate community efforts to outcomes; and reductions in the stage at which cancer is diagnosed as an outcome measure.

Adult↗

PubMed2002

Synthesis, characterization, and bonding properties of polymeric fullerides AC70.nNH3 (A = Ca, Sr, Ba, Eu, Yb).

Reduction of C70 with alkaline earth and rare earth metals dissolved in liquid ammonia results in metal fulleride solvates AC70.nNH3 (A = Ca, Sr, Ba, Eu, Yb) containing linear polymeric, anionic chains infinity 1 [C70(2-)]. The compounds were characterised by means of Raman spectroscopy and single-crystal structure determination. The accurate crystal structure of [Sr(NH3)8]C70.3NH3, determined with atomic resolution, allowed for a comparison with results of quantum chemical calculations. The nature of the C-C bonds in the fulleride is analysed in detail leading to a model explaining the unexpected polymerisation of C70(2-).

Journal Article↗

PubMed2000

Visualization of pressure distribution within loaded joint cartilage by application of angle-sensitive NMR microscopy.

High-resolution MRI measurements on knee joints show a multilaminar appearance of the cartilage. This intracartilaginar structure, visualized as hypointense zones in T(2)-weighted MR images is based on the dipolar interaction of water molecules within regions of anisotropic arrangement of collagen network. Using the different angle dependence of the MR signal, zones of radially and tangentially oriented network structures can be distinguished. Information equivalent to that from polarization light microscopy can be derived noninvasively. This is demonstrated by polarization light microscopic reference investigations. It is shown that this multilaminar MRI appearance is sensitively influenced by mechanical stress. A model explaining the contrary behavior of loaded tangential and radial network structures is given. Based on this pressure dependence, a noninvasive determination of mechanical properties is possible. Using the variation of size and intensity of the hypointense zones under pressure, dynamic high resolution MRI yields noninvasive information about the intracartilaginar pressure distribution similar to photoelastic measurements. Magn Reson Med 43:884-891, 2000.

Animals↗

PubMed1985

Generation of melatonin rhythms.

In mammals, information about the environmental photoperiod is relayed from the retina to the suprachiasmatic nuclei (SCN) in the anterior hypothalamus and via the sympathetic nervous system to the pineal gland where it influences the secretion of melatonin. Light plays a dual role: to suppress the release of melatonin and to entrain the circadian rhythm generators in the SCN, which govern the endogenous melatonin rhythm. Under normal daily light-dark cycles melatonin secretion is confined to the dark period. In most photoperiodic species the daily pattern of secretion changes in response to changes in daylength, and this acts as a physiological time cue in the brain for the control of seasonal cycles in reproduction, moulting and other processes. To illustrate the underlying mechanisms that control the melatonin rhythm, results are presented from five experiments in which the blood plasma concentrations of melatonin were measured in Soay rams exposed to a variety of artificial changes in photoperiod including a switch from 16L:8D (16 h light:8 h dark) or 8L:16D to constant darkness, a switch from constant darkness to 1L:23D and a switch from 16L:8D to a 25 h or 23 h light-dark cycle. The results confirm that the melatonin rhythm is generated endogenously and will free-run under constant darkness with a period close to 24 h for at least 10 days. The rhythm can be entrained by exposure to IL:23D with the end of the light period acting as the 'melatonin-on' signal, and phase-shifts in the melatonin rhythm can be induced by phase-shifts in the light-dark cycle. The period for which melatonin concentrations are high each day (melatonin peak) also varies in duration under the different photoperiods, as a result of both the suppressive and the entraining effects of light. Two models explaining the control of melatonin peak duration are discussed.

Animals↗

PubMedDate not supplied

Body size and shape and glycemic control among Maya women in rural Yucatán.

Studies on relationships between aspects of physique and glucose physiology generally focus on clinical glucose tolerance or on fasting glucose or insulin assays showing glycemic status at the time of testing. Little work has examined the associations between body variables and glycemic control, or average past glucose levels in regular living conditions. The aim of this research was to investigate connections between body size and shape and glycemic control. The sample consists of 60 nondiabetic Maya women, ages 40-85 years, residing in 16 rural villages around Mérida, Yucatán. Body morphology was assessed through anthropometric and derived measures of size and shape, including indicators of fat distribution and general adiposity. Glycemic control was measured through microvenous samples analyzed for glycated blood proteins HbA(1c) and fructosamine to demonstrate average circulating glucose under customary living conditions during the previous several months and weeks. Four-variable regression models explain 17% of the variance in HbA(1c) and 25% of the variance in fructosamine. Arm circumference has the largest positive effect on HbA(1c), while weight has the greatest positive impact on fructosamine. The predictor with the largest negative effect on both glycated blood proteins is calf circumference. In general, variables reflecting overall adiposity and central adiposity demonstrate positive associations with HbA(1c) and fructosamine, whereas lean body measures exhibit negative associations. Findings support the value of glycated blood proteins and of less common anthropometric measures, such as calf circumference, in population research on morphological relations with glycemia.

Adult↗

PubMed1992

Cranial capacity evolution in Homo erectus and early Homo sapiens.

This paper investigates patterns of cranial capacity evolution in Homo erectus, early Homo sapiens, and in regional subsamples of H. erectus. Specifically, models explaining evolution of cranial capacity in these taxa are evaluated with statistical techniques developed for the analysis of time series data. Regression estimates of rates of evolution in cranial capacity are also obtained. A non-parametric test for trend suggests that cranial capacity in both H. erectus and early H. sapiens may increase significantly through time. Cranial capacity in an Asian subsample of H. erectus (comprised of Chinese and Indonesian specimens) increases significantly through time. Other subsamples of H. erectus (African, Chinese, and Indonesian) do not appear to increase significantly through time. Regression results generally corroborate results of the test for trend. Spatial and temporal variation may characterize evolution of cranial capacity in H. erectus. Different patterns of cranial capacity evolution may distinguish H. erectus from early H. sapiens.

Africa↗

PubMed2005

Muscle metabolites, detected in urine by proton spectroscopy, correlate with disease damage in juvenile idiopathic inflammatory myopathies.

OBJECTIVE: To assess for novel markers of muscle damage using urinary muscle metabolites by 1H magnetic resonance spectroscopy in patients with juvenile idiopathic inflammatory myopathy (IIM). METHODS: Creatine (Cr), choline (Cho), betaine (Bet), glycine (Gly), trimethylamine oxide (TMAO), and several other metabolites were measured in first morning void urine samples from 45 patients with juvenile IIM and from 35 healthy age-matched controls, and correlated with measures of myositis disease activity and damage. Urinary metabolite to age-adjusted creatinine (Cn) ratios were examined. RESULTS: Age-adjusted initial Cr:Cn, Cho:Cn, Bet:Cn, Gly:Cn, and TMAO:Cn ratios were higher in patients with juvenile IIM than controls (P < 0.01). Cr:Cn ratios showed significant correlations with physician-assessed global disease damage (Spearman rs = 0.37; P = 0.01), Steinbrocker functional class (rs = 0.35; P = 0.02), serum Cr (rs = 0.72; P = 0.001), and lactate dehydrogenase (rs = 0.34; P = 0.03) levels. Cho:Cn (rs = 0.3; P = 0.05), Gly:Cn (rs = 0.33; P = 0.03), and TMAO:Cn (rs = 0.36; P = 0.02) ratios showed a significant correlation with serum aldolase levels. Cho:Cn ratios also showed a significant correlation with aspartate aminotransferase levels (rs = 0.35; P = 0.02). A linear regression model was used to evaluate the factors influencing urinary Cr:Cn ratios in the 43 patients with data sets available at the initial visit. The regression model explained 73% of the variation in Cr:Cn ratios. The most significant factor was the physician-assessed global disease damage (R2 = 0.50, P = 0.015). CONCLUSION: Urinary Cr:Cn, Cho:Cn, Bet:Cn, Gly:Cn, and TMAO:Cn ratios are elevated in juvenile IIM and Cr:Cn correlates strongly with global disease damage. The Cr:Cn ratio may have potential utility as a marker of myositis disease damage.

Adolescent↗

PubMed2001

A model for Sec incorporation with the regions upstream of the UGA Sec codon to play a key role.

For eukaryotic selenoprotein mRNAs, it has been proposed that the SECIS element in the 3'-UTR is required for recognition of UGA as a Sec codon. Some proteins which bind to SECIS (SBP) have been reported. However, it is not clear how the SECIS element in the 3'-UTR can mediate Sec insertion far at the in-frame UGA Sec codons. The idea that there must be a signal near the UGA Sec codon is still being considered. Therefore, we searched for a protein which binds to an RNA sequence surrounding the UGA Sec codon on human GPx mRNA. We found a protein, prepared from bovine brain microsomes, which strongly bound to the RNA fragment upstream of the UGA Sec codon but not to the RNA sequence downstream of the UGA codon. This protein also bound to the SECIS sequence in the 3'-UTR of human GPx, and this binding to SECIS was competed with the RNA fragment upstream of the UGA Sec codon. We also obtained the similar results with the RNA fragments of type I iodothyronine 5'-deiodinase (5'DI) mRNAs. Comparison of such RNA fragments with SECIS fragments revealed similarities in the region upstream of the in-frame UGA Sec codon of several Se-protein mRNAs. The study thus favors a novel model of Sec incorporation at the UGA Sec codon that involves the regions upstream of the UGA codon of mRNAs of mammalian selenoproteins. This model explains that the stem-loop structure covering the UGA codon is recognized by SBP and how the UGA Sec codon escapes from attack by eRF.

3' Untranslated Regions↗

PubMed2005

Impact of assertive community treatment and client characteristics on criminal justice outcomes in dual disorder homeless individuals.

BACKGROUND: People with severe mental illness and substance use disorders (dual disorder) often have considerable contact with the criminal justice system. AIMS: To test the effects of client characteristics on six criminal justice outcomes among homeless (at intake) people with mental illness and substance misuse disorders. METHODS: The sample was of participants in a randomized controlled trial comparing standard treatment, assertive community treatment (ACT) and integrated treatment (IT). Data were analysed using hierarchical logistic regression. RESULTS: Half the sample was arrested and a quarter incarcerated during the two-year follow-up period. The regression models explained between 22% and 35% of the variance of the following criminal justice measures: (1) major offences, (2) minor offences, (3) substance-use-related offences, (4) incarcerations, (5) arrests, and (6) summons. Prior criminal behaviour was the strongest predictor of all of the dependent variables; in general, demographic and diagnostic variables were not. Similarly, neither the type nor the amount of mental health treatment received predicted subsequent criminal behaviour. CONCLUSION: Elsewhere the authors have shown that ACT and IT had advantages for health and stability of accommodation but these analyses suggest that more specialized interventions are needed to reduce criminal behaviour in dual disorder individuals.

Adult↗

PubMed2002

Personality disorders in prisoners and their motivation for dangerous and disruptive behaviour.

OBJECTIVES: To examine the associations between DSM-III, axis II, personality disorder, motivation and disruptive behaviour in prisoners. METHOD: Interviews were carried out with 81 prisoners in prison special units in England using research diagnostic instruments and an item sheet measuring disruptive behaviours and their motivations. Independent associations were established using logistic regression. RESULTS: Specific associations were established between psychopathy and axis II disorders with violent and disruptive behaviour and motivations for these behaviours. CONCLUSIONS: The study supported a cognitive model explaining the functional association between personality disorder and antisocial behaviour. Personality disorders act as predisposing factors influencing the development of motivations and subsequently facilitate the enactment of disordered behaviour, in a linear progression. Assessment of personality disorder should be routine in disruptive and dangerous prisoners.

Adult↗

PubMed1989

A general criterion for molecular recognition: implications for chiral interactions.

A general criterion is formulated for molecular recognition. The criterion for recognition is the inequality of the distance matrices of complexes of different compounds with a resolving agent under ambient experimental conditions. It is shown how this criterion provides for an objective, well-defined, and simple explanation for recognition of chiral compounds. This approach may be used to explain models (e.g., three-point of attachment) and relationships for chiral recognition. It is also shown how one-, two-, or three-point mechanisms are equivalent in this formalism and could result in chiral recognition. Examples are used to illustrate how the so called one- or two-point mechanisms may be operative in many experimental findings. Symmetry requirements of resolving agents may also be derived from considerations of distance matrices. Finally, the reciprocal relationship of chiral resolving agents is easily derived from the present method of analysis.

Models, Molecular↗

PubMed2002

The use of treatments for erectile dysfunction among survivors of prostate carcinoma.

BACKGROUND: The objectives of this survey were to describe the prevalence of using a treatment for erectile dysfunction (ED) among men after therapy for localized prostate carcinoma and to construct models explaining the variance in trying a treatment, treatment success, and adherence to treatment. METHODS: A postal survey was sent to 2636 men in The Cleveland Clinic Foundation's Prostate Cancer Registry who were treated initially with either definitive radiotherapy or prostatectomy for localized prostate carcinoma. The survey asked about demographic items, past and current sexual functioning, and the partner's sexual function. Men were asked about their current and intended use of medical treatments for ED. Standardized questionnaires included the Sexual Self-Schema Scale-Male Version, the International Index of Erectile Function, urinary and bowel symptom scales from the Los Angeles Prostate Cancer Index), and the Short-Form Health Survey. RESULTS: The return rate was 49%. Differences between men who returned the questionnaire and men who did not respond suggest that the sample was weighted toward men who were more interested in staying active sexually. ED was a problem for 85% of men, and 59% of this group used at least 1 treatment for ED. Only 38% of men found that a medical treatment was at least somewhat helpful in improving their sex lives, however, and 30% of respondents still were using at least 1 treatment at the time of the survey. Factors that were associated with the efficacy of treatments for ED and with their continued use included having a sexual partner, younger age, choosing a treatment for prostate carcinoma that was more likely to spare some sexual function, and not having had neoadjuvant or current antiandrogen therapy. Men who tried a greater number of treatments for ED were more likely to find one that worked. Men were more likely to continue using treatments for ED that produced greater improvements in sexual function. CONCLUSIONS: The success of medical treatments for men with ED among long-term survivors of prostate carcinoma is limited. Men prefer noninvasive treatments, although invasive treatments are more effective. Sexual counseling for men and their partners is recommended, because it may increase the use of medical therapies for ED. Creating more realistic expectations in both partners also may enhance treatment adherence.

Adult↗

PubMed2004

Scanning force microscopy based rapid force curve acquisition on supported lipid bilayers: experiments and simulations using pulsed force mode.

In situ pulsed force mode scanning force microscopy (PFM-SFM) images of phase separated solid-supported lipid bilayers are discussed with the help of computer simulations. Simultaneous imaging of material properties and topography in a liquid environment by means of PFM-SFM is severely hampered by hydrodynamic damping of the cantilever. Stiffness and adhesion images of solid-supported membranes consisting of cholesterol, sphingomyelin, and 1,2-dioleyl-phosphatidylcholine obtained in aqueous solution exhibit contrast inversion of adhesion and stiff. ness images depending on parameters such as driving frequency, amplitude, and trigger setting. Simulations using a simple harmonic oscillator model explain experimental findings and give a deeper insight into the way PFM-SFM experiments have to be performed in order to obtain interpretable results and hence pave the way for reliable material contrast imaging at high speed.

Cholesterol↗

PubMed2002

The role of early adverse experience and adulthood stress in the prediction of neuroendocrine stress reactivity in women: a multiple regression analysis.

Sensitization of stress-responsive neurobiological systems as a possible consequence of early adverse experience has been implicated in the pathophysiology of mood and anxiety disorders. In addition to early adversities, adulthood stressors are also known to precipitate the manifestation of these disorders. The present study sought to evaluate the relative role of early adverse experience vs. stress experiences in adulthood in the prediction of neuroendocrine stress reactivity in women. A total of 49 women (normal volunteers, depressed patients, and women with a history of early abuse) underwent a battery of interviews and completed dimensional rating scales on stress experiences and psychopathology, and were subsequently exposed to a standardized psychosocial laboratory stressor. Outcome measures were plasma adrenocorticotropin (ACTH) and cortisol responses to the stress test. Multiple linear regression analyses were performed to identify the impact of demographic variables, childhood abuse, adulthood trauma, major life events in the past year, and daily hassles in the past month, as well as psychopathology on hormonal stress responsiveness. Peak ACTH responses to psychosocial stress were predicted by a history of childhood abuse, the number of separate abuse events, the number of adulthood traumas, and the severity of depression. Similar predictors were identified for peak cortisol responses. Although abused women reported more severe negative life events in adulthood than controls, life events did not affect neuroendocrine reactivity. The regression model explained 35% of the variance of ACTH responses. The interaction of childhood abuse and adulthood trauma was the most powerful predictor of ACTH responsiveness. Our findings suggest that a history of childhood abuse per se is related to increased neuroendocrine stress reactivity, which is further enhanced when additional trauma is experienced in adulthood.

Adrenocorticotropic Hormone↗

PubMed2004

The contribution of anxiety and food restriction on physical activity levels in acute anorexia nervosa.

OBJECTIVE: Excessive exercise is present in 40%-80% of anorexia nervosa (AN) patients. Hyperactivity often plays a role in developing and maintaining AN and represents an obstacle to weight gain in refeeding. Interconnections among caloric restriction, psychopathology, and physical activity in humans with AN are poorly investigated. METHODS: Physical activity and food restriction during the last 3 months and status of body image/slimness ideal were assessed by the Structured Interview of Anorexia and Bulimia Nervosa (SIAB) in 30 adolescent patients with acute AN at admission to inpatient treatment. Anxiety, depression, and obsessive-compulsiveness were assessed with the Symptom Check-List-90-Revised (SCL-90-R). A regression model based on the independent variables body mass index, food reduction, body image/slimness ideal, anxiety, depression, and obsessive-compulsiveness was calculated to determine the relevant prediction variables of physical activity. RESULTS: The regression model explained 64% (R(2) = .64, p = .000) of the variance of physical activity. Only food restriction (p = .006) and anxiety (p = .004) contributed significantly to the variance. DISCUSSION: Our results indicate that anxiety symptoms and food restriction synergistically contribute to increased levels of physical activity in the acute phase of AN.

Acute Disease↗

PubMed1997

System peaks in capillary zone electrophoresis. 3. Practical rules for predicting the existence of system peaks in capillary zone electrophoresis of anions using indirect spectrophotometric detection.

A theoretical and experimental study of the existence and evolution of system peaks in capillary zone electrophoresis (CZE) with indirect spectrophotometric detection is presented with respect to the effect of the number of coions present in the background electrolyte (BGE). It is shown that in BGEs having only one coion (i.e., the UV-absorbing probe anion), the sample produces only negative peaks due to each analyte anion and no system peaks, with the number of sample peaks corresponding to the number of analytes present in the sample injected. In BGEs containing two coions, a sample with one analyte anion produces one negative indirect detection peak and one system peak. The transition between BGEs having one coion and those with two coions has also been studied and it has been shown that an addition of ca. 5% of the second coion to a single coion BGE causes the resulting BGE to behave macroscopically as a regular two-coion BGE. A descriptive model is proposed, based on transient isotachophoresis (transient stacking) of the sample species and of the coion from the BGE which has the closest mobility to the sample ion. This model explains qualitatively the formation and evolution of the sample peak (containing the sample species and being detected by indirect detection due to displacement of the UV-absorbing probe in its zone) and the system peak (containing no sample species and being a vacancy in the continuum of coions of the BGE). It is shown that the system peak may be positive or negative as it corresponds to the situation where the vacancy of one component of the BGE results in an enhanced concentration of the other component. It has been demonstrated that the system peak is created by a vacancy of that component of the BGE which has the greatest difference in mobility relative to that of the sample species. On indirect detection in BGEs containing two coions the sample displaces predominantly the BGE coion which has a mobility closest to that of the analyte anion. In systems with BGEs containing two coions, a sample having n analytes produces n sample peaks and one system peak, the sign and magnitude of which are dependent on the sum of the UV absorbances of the analytes involved. The effect of bicarbonate from atmospheric CO2 has also been studied and it has been shown that weakly alkaline BGEs with a single anionic UV-absorbing coion, such as those currently used for anionic analyses with indirect detection, may suffer from the presence of system peaks due to bicarbonate.

Anions↗

PubMed1988

Single genes from Agrobacterium rhizogenes influence plant development.

The combined expression of the rol A, B, and C loci of Agrobacterium rhizogenes Ri-plasmids establishes, in transgenic tobacco plants, a pathological state called hairy-root syndrome. However, when expressed separately they provoke distinct developmental abnormalities characteristic for each rol gene. Moreover, changes in their mode of expression obtained by replacing the promoters of the rol B and C genes with the cauliflower mosaic virus 35S promoter elicit new and distinct developmental patterns. These results indicate that the different rol gene products have either different targets, or have a qualitatively different effect on the same target. The target(s) must be involved in the control of plant development. Although each of the three rol genes are independently able to promote root formation in tobacco, efficient root initiation and growth is best achieved through the combined activities of more than a single rol gene. Models explaining the biological effects of A. rhizogenes-derived TL-DNA genes are discussed.

Bacterial Proteins↗