High blood pressure is a disease of unknown cause. Family history of the disease indicates higher risk, but it is not known which genes are involved or how they interact with environmental influences to produce the disorder. Molecular biology offers an approach to problems that have not so far been solved by classical physiology or biochemistry. By analysing polymorphic variation in chromosome markers such as minisatellite sequences, or by restriction fragment polymorphism analysis of candidate genes, attempts are being (...) made to link genetic variations with hypertension. In genetically hypertensive rats, hypertension is associated with a polymorphism of the renin gene and with other loci on chromosomes 10 and 18. The role of these loci in human hypertension remains to be determined. Other genes such as sodium‐lithium countertransport may be involved. Environmental factors such as stress or salt intake could influence the rate or timing of expression of certain genes and thus result in hypertension. (shrink)

We provide a methodology for the creation of ontological partitions in biomedicine and we test the methodology via an application to the phenomenon of blood pressure. An ontology of blood pressure must do justice to the complex networks of intersecting pathways in the organism by which blood pressure is regulated. To this end it must deal not only with the anatomical structures and physiological processes involved in such regulation but also with the relations between (...) these at different levels of granularity. For this purpose our ontology offers a variety of distinct partitions � of substances, processes and functions � and integrates these together within a single framework via transitive networks of part-whole and dependence relations among the entities in each of these categories. The paper concludes with a comparison of this methodology with the approaches of GOTM, KEGG, DIP and BIND and provides an outline of how the methodology is currently being applied in the field of biomedical database integration. (shrink)

SummaryAggarwal Baniyas were found to have a high prevalence of high blood pressure. Genetic and environmental influences may be implicated for this risk factor of cardiovascular disease. The aim of this study was to investigate the potential for common genetic and environmental influences on blood pressure measures ). The population-based sample was comprised of 309 Aggarwal Baniya families, including 1214 individuals from New Delhi, India. The prevalence of obesity in this community was found to be high. (...) Correlation and heritability were estimated. Most sibling–sibling correlations were larger than the parent–offspring correlations, and all parent–offspring and sibling–sibling correlations were larger than the corresponding spouse correlation. The maximum heritability was estimated as 44.6% for SBP and 62.8% for DBP. The lack of a significant spouse correlation is consistent with little or no influence of the common familial environment. However, the high heritability estimate for both SBP and DBPs reinforces the importance of the non-shared environmental effect. (shrink)

The renin-angiotensin system (RAS) is critical in sodium and blood pressure (BP) regulation, and in cardiovascular-renal (CVR) diseases and therapeutics. As a contribution to SAPHIR project, we present a realistic computer model of renin production and circulating RAS, integrated into Guyton’s circulatory model ( GCM ). Juxtaglomerular apparatus, JGA , and Plasma modules were implemented in C ++/M2SL (Multi-formalism Multi-resolution Simulation Library) for fusion with GCM . Matlab © optimization toolboxes were used for parameter identification. In JGA , (...) renin production and granular cells recruitment (GCR) are controlled by perfusion pressure (PP), macula densa (MD), angiotensin II (Ang II), and renal sympathetic activity (RSNA). In Plasma , renin and ACE (angiotensin-converting enzyme) activities are integrated to yield Ang I and II. Model vs. data deviation is given as normalized root mean squared error (nRMSE; n points). Identification: JGA and Plasma parameters were identified against selected experimental data. After fusion with GCM : (1) GCR parameters were identified against Laragh’s PRA-natriuresis nomogram; (2) Renin production parameters were identified against two sets of data ([renin] transients vs. ACE or renin inhibition). Finally, GCR parameters were re-identified vs. Laragh’s nomogram (nRMSE 8%, n = 9). Validation: (1) model BP, PRA and [Ang II] are within reported ranges, and respond physiologically to sodium intake; (2) short-term Ang II infusion induces reported rise in BP and PRA. The modeled circulating RAS, in interaction with an integrated CVR, exhibits a realistic response to BP control maneuvers. This construction will allow for modelling hypertensive and CVR patients, including salt-sensitivity, polymorphisms, and pharmacotherapeutics. (shrink)

Hypertension is a common disease in highly industrialized societies, more often perceived as a health problem in adults rather than children. However, epidemiologists are currently paying more attention to the possibility of idiopathic hypertension during childhood. This article compares three classification models (logistic regression, classification trees and MARSplines) in order to determine the best classification model and distinguish the parameters that are most important in the detection of abnormal blood pressure in children. The study group consisted of 1,378 (...) children aged between 7 and 18. After making comparisons between the methods, it was determined that MARSplines is the model that best assigns subjects to classes and can be an alternative in cases when traditional statistical methods cannot be used due to a lack of fulfillment of conditions. For prediction of abnormal blood pressure in this age group, the most important parameters were the heart rate and selected indicators of body proportions. (shrink)

The use of contraceptives has become prevalent among females in Thailand in the past 20 years, and oral contraceptive use has been suggested to trigger changes in fat intake, energy expenditure, fat metabolism and blood pressure. Based on field investigations of 391 married women aged 20 years or over in Yasothon Province, North-east Thailand, this study aims to elucidate the effects of oral contraceptive use on body mass index (BMI: kg/m2 ) and blood pressure, taking into (...) account reproductive histories and socioeconomic conditions. The proportion of obese (BMI> 25) subjects was high in the age groups 3049 and 5049, 5069 age groups. Current contraceptive practices in the studied population included sterilization by operation, oral contraception and injection. These methods accounted for 43·0%, 12·8% and 8·2% of the population, respectively. Sociodemographic factors such as reproductive history, years of education and household income were not significantly related to BMI or to blood pressure (ANOVA with age adjustment). In contrast, oral contraceptive users had significantly higher BMIs and diastolic blood pressures (p<0·01, ANOVA with age adjustment). Multiple regression analysis also revealed that oral contraceptive use was a weak but significant contributing factor to both high BMI and blood pressure when sociodemographic factors were taken into account and controlled for statistically. It can thus be concluded that the use of contraceptive pills, which contain oestrogen and progestin and are provided free of charge to Thai women, tend to increase BMI and to elevate blood pressure. (shrink)

Tell us what you think This essay was first posted at Edge (www.edge.org) and is reprinted with permission. It is the Preface to the book 'What Is Your Dangerous Idea?: Today's Leading Thinkers on the Unthinkable,' published by HarperCollins. Write to [email protected]..

Patients with schizophrenia have a higher risk of cardiovascular diseases and higher mortality from them than does the general population; however, the underlying mechanism remains unclear. Impaired cerebral autoregulation is associated with cerebrovascular diseases and their mortality. Increased or decreased cerebral blood flow in different brain regions has been reported in patients with schizophrenia, which implies impaired cerebral autoregulation. This study investigated the cerebral autoregulation in 21 patients with schizophrenia and 23 age- and sex-matched healthy controls. None of the (...) participants had a history of cardiovascular diseases, hypertension, or diabetes. All participants underwent 10-min blood pressure and cerebral blood flow recording through finger plethysmography and Doppler ultrasonography, respectively. Cerebral autoregulation was assessed by analyzing two autoregulation indices: the mean blood pressure and cerebral blood flow correlation coefficient (Mx), and the phase shift between the waveforms of blood pressure and cerebral blood flow determined using transfer function analysis. Compared with the controls, the patients had a significantly higher Mx (0.257 vs. 0.399, p = 0.036) and lower phase shift (44.3° vs. 38.7° in the 0.07–0.20 Hz frequency band, p = 0.019), which indicated impaired maintenance of constant cerebral blood flow and a delayed cerebrovascular autoregulatory response. Impaired cerebral autoregulation may be caused by schizophrenia and may not be an artifact of coexisting medical conditions. The mechanism underlying impaired cerebral autoregulation in schizophrenia and its probable role in the development of cerebrovascular diseases require further investigation. (shrink)

Although previous studies have found that video games induce stress, studies have not typically measured all salient indicators of stress responses including stress appraisals, cardiovascular indicators, and emotion outcomes. The current study used the Biopsychosocial Model of Challenge and Threat (Blascovich & Tomaka, 1996) to determine if video games induce a cardiovascular stress response by comparing the effects of threat and challenge appraisals across two types of video games that have shown different cardiovascular outcomes. Participants received challenge or threat appraisal (...) instructions, and played a fighting game (Mortal Kombat) or a puzzle game (Tetris). Study outcomes were heart rate variability, systolic and diastolic blood pressure, and positive and negative emotion ratings measured before, during and after gameplay. Results indicated that threat appraisal instructions increased negative emotion ratings and decreased heart rate variability, but not blood pressure, which is an essential marker for cardiovascular stress responses. Increased blood pressure and decreased heart rate variability was associated with fighting game players when compared with the puzzle game players, indicating a cardiovascular stress response; however, fighting game players also reported higher positive emotion ratings. Based on the study findings, video games do not induce stress responses like mental stressors used in previous research, demonstrating that the interactive player experience in video gaming may have more complex effects on stress outcomes. Future research should comprehensively measure biopsychosocial stress indicators and multiple emotional states over time to fully examine the relationship between video games and stress. (shrink)

The ABO histo‐blood group, first discovered over a century ago, is found not only in humans but also in many other primate species, with the same genetic variants maintained for at least 20 million years. Polymorphisms in ABO have been associated with susceptibility to a large number of human diseases, from gastric cancers to immune or artery diseases, but the adaptive phenotypes to which the polymorphism contributes remain unclear. We suggest that variation in ABO has been maintained by frequency‐dependent (...) or fluctuating selection pressures, potentially arising from co‐evolution with gut pathogens. We further hypothesize that the histo‐blood group labels A, B, AB, and O do not offer a full description of variants maintained by natural selection, implying that there are unrecognized, functionally important, antigens beyond the ABO group in humans and other primates. (shrink)

Many biosystems are complex mixtures of disparate biofluids. To study contact and transport phenomena in these mixtures, one has to apply much information on the biofluids which are components of the mixtures. A lot of the corresponding data can be extracted by means of experiments. However, it is not always easy to obtain experimental results on rather deep physical characteristics of biofluids, especially if the bioparticles are complicated systems and the fluid coexists in the mixture with a large number of (...) other fluids. In these cases, the necessary data can, in principle, be extracted from those results which are easier to obtain experimentally. The present work proposes a method to evaluate the biofluid equilibrium pressure and electrochemical potential from common experimental values of the fluid concentration and absolute temperature as well as the fluid-particle mass, volume and spin. In so doing, the nonzero values of the particle volume are accounted for. The procedure is illustrated with a numerical example on the fluid of red blood cells (or erythrocytes) in human blood. The pressure values obtained are 49.1 and 38.8 micropascals for men and women respectively whereas the electrochemical-potential values are –2.124 and –2.130 electronvolts for men and women respectively. (shrink)

Jehovah's Witnesses are students of the Bible. They refuse transfusions out of obedience to the scriptural directive to abstain and keep from blood. Dr Muramoto disagrees with the Witnesses' religious beliefs in this regard. Despite this basic disagreement over the meaning of Biblical texts, Muramoto flouts the religious basis for the Witnesses' position. His proposed policy change about accepting transfusions in private not only conflicts with the Witnesses' fundamental beliefs but it promotes hypocrisy. In addition, Muramoto's arguments about (...) class='Hi'>pressure to conform and coerced disclosure of private information misrepresent the beliefs and practices of Jehovah's Witnesses and ignore the element of individual conscience. In short, Muramoto resorts to distortion and uncorroborated assertions in his effort to portray a matter of religious faith as a matter of medical ethical debate. (shrink)

Mr Ridley of the Watch Tower Society , the controlling religious organisation of Jehovah's Witnesses , mischaracterises the issue of freedom and confidentiality in JWs' refusal of blood by confusing inconsistent organisational policies with actual Biblical proscriptions. Besides exaggeration and distortion of my writings, Ridley failed to present substantive evidence to support his assertion that no pressure exists to conform to organisational policy nor systematic monitoring which compromises medical confidentiality. In this refutation, I present proof from the WTS's (...) literature, supported by personal testimonies of JWs, that the WTS enforces its policy of blood refusal by coercive pressure to conform and through systematic violation of medical confidentiality. Ridley's lack of candour in dealing with the plea of dissident JWs for freedom to make personal and conscientious decisions regarding blood indicates that a serious breach of ethics in the medical care of JWs continues. The medical community should be seriously concerned. (shrink)

High blood pressure is an important component of pre-eclampsia. The underlying mechanism of development of hypertension in pre-eclampsia is complicated and still remains obscure. Several theories have been advanced including endothelial dysfunction, uteroplacental insufficiency leading to generalized vasoconstriction, increased cardiac output, and sympathetic hyperactivity. Increased blood flow and pressure are thought to lead to capillary dilatation, which damages end-organ sites, leading to hypertension, proteinuria and edema. Additional theories have been put forward based on epidemiological research, implicating (...) immunological and genetic factors. None of these theories have been substantiated. Based on a review of literature this paper postulates that the initiating event for the development of preeclampsia is intermittent hypoxia associated with irregular breathing during sleep, hypoapnea, apnea,inadequate respiratory excursions during the waking hours and inadequate cardiopulmonary synchronization (abnormal sympatho-vagal balance). (shrink)

High blood pressure (HBP) is a multifactorial clinical condition characterized by high and sustained levels of blood pressure (BP), and the presence of elevated BP in childhood is predictor of hypertension in adult life. Studies have shown a positive correlation between sodium chloride ingested in the diet and blood pressure values. This study aims to evaluate the consumption of added salt before and after awareness of risk, by high school students. This occurred for three (...) days in the refectory, where students received illustrative brochure with information about sodium intake; exhibition of a poster illustrating foods with their respective equivalent amount of sodium and sodium chloride, exemplifying the maximum recommended amount of consumption per day. For five days, before and after gaining awareness, it the amount of consumption of sachets of salt was accounted. Statistical analyzes were performed by Student's Test, with a confidence interval of 95%. During the study period were served on average 128.3 meals. Before the awareness of sodium consumption of risks, of 820mg and 330mg sodium salt was consumed an average per individual, and thereafter, 640mg and 260mg, respectively (p=0,043). Simple Nutrition Education Strategies in short term were effective for improving the consumption of added salt in adolescents. (shrink)

The classic model of blood pressure regulation by Guyton et al. (Annu Rev Physiol 34:13–46, 1972a; Ann Biomed Eng 1:254–281, 1972b) set a new standard for quantitative exploration of physiological function and led to important new insights, some of which still remain the focus of debate, such as whether the kidney plays the primary role in the genesis of hypertension (Montani et al. in Exp Physiol 24:41–54, 2009a; Exp Physiol 94:382–388, 2009b; Osborn et al. in Exp Physiol 94:389–396, (...) 2009a; Exp Physiol 94:388–389, 2009b). Key to the success of this model was the fact that the authors made the computer code (in FORTRAN) freely available and eventually provided a convivial user interface for exploration of model behavior on early microcomputers (Montani et al. in Int J Bio-med Comput 24:41–54, 1989). Ikeda et al. (Ann Biomed Eng 7:135–166, 1979) developed an offshoot of the Guyton model targeting especially the regulation of body fluids and acid–base balance; their model provides extended renal and respiratory functions and would be a good basis for further extensions. In the interest of providing a simple, useable version of Ikeda et al.’s model and to facilitate further such extensions, we present a practical implementation of the model of Ikeda et al. (Ann Biomed Eng 7:135–166, 1979), using the ODE solver Berkeley Madonna. (shrink)

Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart (...) rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain. (shrink)

The classic model of blood pressure regulation by Guyton et al. set a new standard for quantitative exploration of physiological function and led to important new insights, some of which still remain the focus of debate, such as whether the kidney plays the primary role in the genesis of hypertension. Key to the success of this model was the fact that the authors made the computer code freely available and eventually provided a convivial user interface for exploration of (...) model behavior on early microcomputers. Ikeda et al. developed an offshoot of the Guyton model targeting especially the regulation of body fluids and acid–base balance; their model provides extended renal and respiratory functions and would be a good basis for further extensions. In the interest of providing a simple, useable version of Ikeda et al.’s model and to facilitate further such extensions, we present a practical implementation of the model of Ikeda et al., using the ODE solver Berkeley Madonna. (shrink)

This book tells the story of the Scientific Buddha, "born" in Europe in the 1800s but commonly confused with the Buddha born in India 2,500 years ago. The Scientific Buddha was sent into battle against Christian missionaries, who were proclaiming across Asia that Buddhism was a form of superstition. He proved the missionaries wrong, teaching a dharma that was in harmony with modern science. And so his influence continues. Today his teaching of "mindfulness" is heralded as the cure for all (...) manner of maladies, from depression to high blood pressure.In this potent critique, a well-known chronicler of the West's encounter with Buddhism demonstrates how the Scientific Buddha's teachings deviate in crucial ways from those of the far older Buddha of ancient India. Donald Lopez shows that the Western focus on the Scientific Buddha threatens to bleach Buddhism of its vibrancy, complexity, and power, even as the superficial focus on "mindfulness" turns Buddhism into merely the latest self-help movement. The Scientific Buddha has served his purpose, Lopez argues. It is now time for him to pass into nirvana. This is not to say, however, that the teachings of the ancient Buddha must be dismissed as mere cultural artifacts. They continue to present a meaningful challenge, even to our modern world. (shrink)

It probably should not be surprising, in this time of soaring medical costs and proliferating technology, that an intense debate has arisen over the concept of medical futility. Should doctors be doing all the things they are doing? In particular, should they be attempting treatments that have little likelihood of achieving the goals of medicine? What are the goals of medicine? Can we agree when medical treatment fails to achieve such goals? What should the physician do and not do under (...) such circumstances? Exploring these issues has forced us to revisit the doctor-patient relationship and the relationship of the medical profession to society in a most fundamental way. Medical futility has both a quantitative and qualitative component. I maintain that medical futility is the unacceptable likelihood of achieving an effect that the patient has the capacity to appreciate as a benefit. Both emphasized terms are important. A patient is neither a collection of organs nor merely an individual with desires. Rather, a patient (from the word to suffer ) is a person who seeks the healing (meaning to make whole ) powers of the physician. The relationship between the two is central to the healing process and the goals of medicine. Medicine today has the capacity to achieve a multitude of effects, raising and lowering blood pressure, speeding, slowing, and even removing and replacing the heart, to name but a minuscule few. But none of these effects is a benefit unless the patient has at the very least the capacity to appreciate it. Sadly, in the futility debate wherein some critics have failed or refused to define medical futility an important area of medicine has in large part been neglected, not only in treatment decisions at the bedside, but in public discussions—comfort care—the physician’s obligation to alleviate suffering, enhance well being and support the dignity of the patient in the last few days of life. (shrink)

What counts as health or ill health? How do we deal with the fallibility of our own bodies? Should illness and disease be considered simply in biological terms, or should considerations of its emotional impact dictate our treatment of it? Our understanding of health and illness had become increasingly more complex in the modern world, as we are able to use medicine not only to fight disease but to control other aspects of our bodies, whether mood, blood pressure, (...) or cholesterol. This collection of essays foregrounds the concepts of health and illness and patient experience within the philosophy of medicine, reflecting on the relationship between the ill person and society. Mental illness is considered alongside physical disease, and the important ramifications of society's differentiation between the two are brought to light. Health, Illness and Disease is a significant contribution to shaping the parameters of the evolving field of philosophy of medicine and will be of interest to medical practitioners and policy-makers as well as philosophers of science and ethicists. (shrink)

This paper juxtaposes Asian spiritual narratives on meditation alongside medical and scientific narratives that emphasize meditation's efficacy in mitigating distress and increasing well-being. After proposing a working definition of meditation that enables it usefully to be distinguished from categories of similar practices such as prayer, I examine meditation's role in Mind/Body medicine in the West. Here, I survey a number of scientific studies of meditation, including the work of Dr. Herbert Benson and his colleagues who examine a meditational variant they (...) call the ‘Relaxation Response', to examine the breadth of efficacy claims made on behalf of the complex and multidimensional grouping of diverse practices we have come to as ‘meditation'. Among other positive outcomes, meditation has been credited with reducing blood pressure, anxiety, addiction, and stress, while Relaxation Response has been shown to decrease sympathetic nervous system activity, metabolism, pain, anxiety, depression, hostility, and stress. I conclude the paper by suggesting that findings from cognitive neuroscience on the subject of visual imagery can be used to elucidate genres of meditative practice that focus on internal visualization sequences, and I use practices from the Rnying ma tradition of Tibetan Buddhism to illustrate why certain integral aspects of meditation forever will remain beyond scientific grasp. (shrink)

Conflicts of interest are rampant in the American medical community. Today it is not uncommon for doctors to refer patients to clinics or labs in which they have a financial interest (40% of physicians in Florida invest in medical centers); for hospitals to offer incentives to physicians who refer patients (a practice that can lead to unnecessary hospitalization); or for drug companies to provide lucrative give-aways to entice doctors to use their "brand name" drugs (which are much more expensive than (...) generic drugs). In Medicine, Money and Morals, Marc A. Rodwin draws on his own experience as a health lawyer--and his research in health ethics, law, and policy--to reveal how financial conflicts of interest can and do negatively affect the quality of patient care. He shows that the problem has become worse over the last century and provides many actual examples of how doctors' decisions are influenced by financial considerations. We learn how two California physicians, for example, resumed referrals to Pasadena General Hospital only after the hospital started paying $70 per patient (their referrals grew from 14 in one month to 82 in the next). As Rodwin writes, incentives such as this can inhibit a doctor from taking action when a hospital fails to provide proper service, and may also lead to the unnecessary hospitalization of patients. We also learn of a Wyeth-Ayerst Labs promotion in which physicians who started patients on INDERAL (a drug for high blood pressure, angina, and migraines) received 1000 mileage points on American Airlines for each patient (studies show that promotions such as this have a direct effect on a doctor's choice of drug). Rodwin reveals why the medical community has failed to regulate conflicts of interest: peer review has little authority, state licensing boards are usually ignorant of abuses, and the AMA code of ethics has historically been recommended rather than required. He examines what can be learned from the way society has coped with the conflicts of interest of other professionals --lawyers, government officials, and businessmen--all of which are held to higher standards of accountability than doctors. And he recommends that efforts be made to prohibit and regulate certain kinds of activity (such as kickbacks and self-referrals), to monitor and regulate conduct, and to provide penalties for improper conduct. Our failure to face physicians' conflicts of interest has distorted the way medicine is practiced, compromised the loyalty of doctors to patients, and harmed society, the integrity of the medical profession, and patients. For those concerned with the quality of health care or medical ethics, Medicine, Money and Morals is a provocative look into the current health care crisis and a powerful prescription for change. (shrink)

We introduce the Vital Sign Ontology (VSO), an extension of the Ontology for General Medical Science (OGMS) that covers the consensus human vital signs: blood pressure, body temperature, respiratory rate, and pulse rate. VSO provides a controlled structured vocabulary for describing vital sign measurement data, the processes of measuring vital signs, and the anatomical entities participating in such measurements. VSO is implemented in OWL-DL and follows OBO Foundry guidelines and best practices. If properly developed and extended, we believe (...) the VSO will find applications for the EMR, clinical informatics, and medical device communities. (shrink)