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PubMed2004

Temporal dynamics of rabies in a wildlife host and the risk of cross-species transmission.

An epidemiological model was developed for rabies, linking the risk of disease in a secondary species (cats) to the temporal dynamics of disease in a wildlife reservoir (raccoons). Data were obtained from cats, raccoons, and skunks tested for rabies in the northeastern United States during 1992-2000. An epizootic algorithm defined a time-series of successive intervals of epizootic and inter-epizootic raccoon rabies. The odds of diagnosing a rabid cat during the first epizootic of raccoon rabies was 12 times greater than for the period prior to epizootic emergence. After the first raccoon epizootic, the risk for cat rabies remained elevated at levels six- to seven-fold above baseline. Increased monthly counts of rabid raccoons and skunks and decreasing human population density increased the probability of cat rabies in most models. Forecasting of the public health and veterinary burden of rabies and assessing the economics of control programmes, requires linking outcomes to dynamic, but predictable, changes in the temporal evolution of rabies epizootics.

Animals↗

PubMed2026

In vitro fertilization-conceived offspring exhibit altered Long Interspersed Nuclear Elements-1 retrotransposition dynamics associated with long-term disease risks.

BACKGROUND: In vitro fertilization has transformed reproductive medicine, yet offspring conceived through in vitro fertilization display elevated risks for diverse long-term health conditions, with underlying mechanisms unclear. Long Interspersed Nuclear Elements-1, a mobile genetic element responsive to environmental stress, represents a potential mediator. OBJECTIVE: This study aimed to test the hypothesis that in vitro fertilization procedures may act as an embryonic stressor that alters Long Interspersed Nuclear Elements-1 dynamics, potentially contributing to genomic instability associated with long-term disease susceptibility. STUDY DESIGN: Umbilical cord blood or peripheral blood from 33 in vitro fertilization and 42 naturally conceived neonates were collected for whole-genome sequencing. Total Long Interspersed Nuclear Elements-1 proportion in individual genome was counted with Bowtie2 software. De novo Long Interspersed Nuclear Elements-1 insertion and Long Interspersed Nuclear Elements-1 deletion were detected with Mobile Element Locator Tool. Three parent-matched in vitro fertilization-naturally conceived sibling pairs were included to control for genetic background. Disease association analysis was performed for genes within 500 kb of differential Long Interspersed Nuclear Elements-1 sites in The Database for Annotation, Visualization and Integrated Discovery (DAVID). Statistical analysis was performed using the R language. RESULTS: In vitro fertilization offspring demonstrate elevated global Long Interspersed Nuclear Elements-1 content compared to naturally conceived controls (P=.04). This finding was corroborated in 3 sibling pairs from identical genetic backgrounds, where in vitro fertilization-conceived children consistently exhibited higher Long Interspersed Nuclear Elements-1 levels than their naturally conceived siblings. Eleven genomic loci with differential Long Interspersed Nuclear Elements-1 insertion frequencies and 14 loci with differential Long Interspersed Nuclear Elements-1 deletion frequencies between in vitro fertilization offspring and naturally conceived controls were identified. Notably, these differential Long Interspersed Nuclear Elements-1 sites demonstrated significant enrichment near genes implicated in metabolic, cardiovascular, neuropsychiatric, and neoplastic diseases, conditions associated with in vitro fertilization conception. CONCLUSION: These findings provide preliminary evidence that in vitro fertilization conception is associated with increased Long Interspersed Nuclear Elements-1 content and altered genomic distribution of Long Interspersed Nuclear Elements-1 elements. The proximity of these differential Long Interspersed Nuclear Elements-1 sites to disease-associated genes suggests a plausible genomic mechanism linking in vitro fertilization-associated embryonic stress to elevated disease risk. This work provides valuable molecular insights that may inform the ongoing discussion about assisted reproductive technology safety and suggests that continued attention to genomic integrity in in vitro fertilization-conceived individuals would be beneficial.

Humans↗

PubMed2003

Spatial and temporal variations of malaria epidemic risk in Ethiopia: factors involved and implications.

The aim of this study was to describe spatial and temporal variations in malaria epidemic risk in Ethiopia and to examine factors involved in relation to their implications for early warning and interpretation of geographical risk models. Forty-eight epidemic episodes were identified in various areas between September 1986 and August 1993 and factors that might have led to the events investigated using health facility records and weather data. The study showed that epidemics in specific years were associated with specific geographical areas. A major epidemic in 1988 affected the highlands whereas epidemics in 1991 and 1992 affected highland-fringe areas on the escarpments of the Rift Valley and in southern and north-western parts of the country. Malaria epidemics were significantly more often preceded by a month of abnormally high minimum temperature in the preceding 3 months than based on random chance, whereas frequency of abnormally low minimum temperature prior to epidemics was significantly lower than expected. Abnormal increases of maximum temperature and rainfall had no positive association with the epidemics. A period of low incidence during previous transmission seasons might have aggravated the events, possibly due to low level of immunity in affected populations. Epidemic risk is a dynamic phenomenon with changing geographic pattern based on temporal variations in determinant factors including weather and other eco-epidemiological characteristics of areas at risk. Epidemic early warning systems should take account of non-uniform effects of these factors by space and time and thus temporal dimensions need to be considered in spatial models of epidemic risks.

Animals↗

PubMed2006

Speaking the truth in maritime risk assessment.

Several major risk studies have been performed in recent years in the maritime transportation domain. These studies have had significant impact on management practices in the industry. The first, the Prince William Sound risk assessment, was reviewed by the National Research Council and found to be promising but incomplete, as the uncertainty in its results was not assessed. The difficulty in assessing this uncertainty is the different techniques that need to be used to model risk in this dynamic and data-scarce application area. In previous articles, we have developed the two pieces of methodology necessary to assess uncertainty in maritime risk assessment, a Bayesian simulation of the occurrence of situations with accident potential and a Bayesian multivariate regression analysis of the relationship between factors describing these situations and expert judgments of accident risk. In this article, we combine the methods to perform a full-scale assessment of risk and uncertainty for two case studies. The first is an assessment of the effects of proposed ferry service expansions in San Francisco Bay. The second is an assessment of risk for the Washington State Ferries, the largest ferry system in the United States.

Journal Article↗

PubMed2003

Increased risk of falls and increased bone resorption in elderly men with partial androgen deficiency: the MINOS study.

The goal of this study was to identify the clinical and biological patterns of hypogonadism in a cohort of 1040 elderly men. Residual androgenic activity was estimated by total testosterone as well as the apparent free testosterone concentration (AFTC) and free testosterone index (FTI) calculated on the basis of concentrations of SHBG and total testosterone using appropriate formulae. The lower limit of the normal range defined by 2 SD below the mean in 150 healthy, nonobese, and nonsmoking men, aged 19-40 yr, was calculated for total testosterone (9.26 nmol/liter), AFTC (146 pmol/liter), and FTI (0.14 nmol/nmol). The prevalence of hypogonadism increased with ageing. Hypogonadal men were older and heavier (due to a higher fat body mass) and had lower concentrations of 17 beta-estradiol and androstenedione than men with normal androgenic activity. Men with decreased AFTC had a slightly lower bone mineral density (BMD) at certain sites. Men with decreased FTI had lower appendicular skeletal muscle mass and relative skeletal muscle index. For all three measures of androgenic activity, hypogonadal men had increased levels of the markers of bone resorption. In the multiple regression models including both 17 beta-estradiol and testosterone (total, AFTC, or FTI), 17 beta-estradiol was the only significant determinant of BMD. In the multiple regression models including 17 beta-estradiol and AFTC or FTI, only testosterone was a significant determinant of the variability in bone formation markers, whereas both 17 beta-estradiol and testosterone were significant determinants of the variability of the markers of bone resorption. Hypogonadism was associated with an increase in the risk of falls, an impairment of static and dynamic balance, as well as the inability to stand up from a chair and to perform the tandem walk. Decreased AFTC (<146 pmol/liter) discriminated best men with functional disabilities (odds ratio, 1.54-7.95; P < 0.05-0.0001). Hypogonadal elderly men had increased bone resorption that was not adequately matched by an increase in bone formation, lower muscle strength, impaired static and dynamic balance, a higher risk of falls, and, in men with low AFTC, a slightly lower BMD. Low AFTC seems to have the best discriminative power for densitometric, biochemical, and functional parameters, followed by FTI, whereas total testosterone was the least discriminative. In multiple regression models, 17 beta-estradiol was the strongest determinant of BMD, and AFTC and FTI were significant determinants of the variability in bone formation markers, whereas both 17 beta-estradiol and testosterone determined the variability in bone resorption markers.

Accidental Falls↗

PubMed2001

Diet and drug therapy: a dynamic duo for reducing coronary heart disease risk.

A large proportion of the United States population requires aggressive low-density lipoprotein (LDL) cholesterol- lowering therapy to meet the new treatment guidelines established by the National Cholesterol Education Program Adult Treatment Panel III. This has further widened the gap between the number of people being treated compared with those who should be treated. Moreover, many people being treated do not meet their LDL cholesterol goal. Diet and healthy lifestyle practices remain the cornerstone of treatment to lower LDL cholesterol. Pharmacologic therapy has assumed an increasingly important role in reaching LDL cholesterol goals. Diet and healthy-lifestyle interventions have been shown to augment the benefits of cholesterol-lowering drugs. Together, this dynamic duo provides the most effective clinical means identified to date for maximally lowering LDL cholesterol levels.

Anticholesteremic Agents↗

PubMed2006

The dynamics of injection drug users' personal networks and HIV risk behaviors.

AIMS: While studies of the social networks of injection drug users (IDUs) have provided insight into how the structures of interpersonal relationships among IDUs affect HIV risk behaviors, the majority of these studies have been cross-sectional. The present study examined the dynamics of IDUs' social networks and HIV risk behaviors over time. DESIGN: Using data from a longitudinal HIV-intervention study conducted in Baltimore, MD, this study assessed changes in the composition of the personal networks of 409 IDUs. We used a multi-nomial logistic regression analysis to assess the association between changes in network composition and simultaneous changes in levels of injection HIV risk behaviors. Using the regression parameters generated by the multi-nomial model, we estimated the predicted probability of being in each of four HIV risk behavior change groups. FINDINGS: Compared to the base case, individuals who reported an entirely new set of drug-using network contacts at follow-up were more than three times as likely to be in the increasing risk group. In contrast, reporting all new non-drug-using contacts at follow-up increased the likelihood of being in the stable low-risk group by almost 50% and decreased the probability of being in the consistently high-risk group by more than 70%. CONCLUSIONS: The findings from this study show that, over and above IDUs' baseline characteristics, changes in their personal networks are associated with changes in individuals' risky injection behaviors. They also suggest that interventions aimed at reducing HIV risk among IDUs might benefit from increasing IDUs' social contacts with individuals who are not drug users.

Adolescent↗

PubMed2003

Relapse as a nonlinear dynamic system: application to patients with alcohol use disorders.

Understanding the relapse process is one of the most important issues in addictive behaviors research. To date, most studies have taken a linear approach toward predicting relapse based on risk factors. Nonlinear dynamical systems theory can be used to describe processes that are not adequately modeled using a linear approach. In particular, the authors propose that catastrophe theory, a subset of nonlinear dynamical systems theory, can be used to describe the relapse process in addictive behaviors. Two small prospective studies using 6-month follow-ups of patients with alcohol use disorders (inpatient, n = 51; outpatient, n = 43) illustrate how cusp catastrophe theory may be used to predict relapse. Results from these preliminary studies indicate that a cusp catastrophe model has more predictive utility than traditional linear models.

Adult↗

PubMed2005

Estimating the risk for atherothrombosis: are current approaches sufficient?

Atherothrombotic disease is now the leading cause of mortality in the world and there are only a few methods available to estimate risk of vascular disease. Vascular disease risk assessment methods have been developed from a variety of population based studies and the most frequently used approaches include algorithms developed by Framingham (USA), Munster (Germany), and SCORE (Europe). The field of risk estimation is dynamic and inclusion of newer factors and populations is under active consideration and methods such as discrimination and calibration are now available to evaluate the use of risk assessment tools across different world regions.

Algorithms↗

PubMed1997

Atherogenic lipids, vascular dysfunction, and clinical signs of ischemic heart disease.

LDL is oxidized in vascular endothelial cells to a highly injurious product that results in characteristic cell dysfunction(s) in large arteries and resistance vessels. The characteristic dysfunctions (ie, loss of dilation, constriction, thrombosis, and inflammation) operate before and throughout the development of atherosclerosis and particularly during plaque rupture. Although oxidized LDL appears to induce these cell/vessel wall dysfunctions in a time- and concentration-dependent manner, Tamai and colleagues have shown that this interaction can be dynamic in that a reduction in lipids restores endothelium-dependent vasomotor function almost immediately. The same intervention (ie, lipid lowering) also appears to stabilize atheroma in the long term, improves endothelium-dependent vasomotion over months, and results in a reduction in clinical signs of risk in coronary heart disease (ie, ischemia and the need for revascularization). The above leads us to some important but unanswered questions. Can we rely on clinical measures of arterial vasomotor dysfunction to represent the other important cell dysfunctions (eg, inflammation, abnormal growth) while monitoring the response to therapeutic interventions? How can we effectively inhibit oxidation of LDL in the arterial wall, and is this useful in reversing the many cell dysfunctions and clinical sequelae of coronary atherosclerosis? What is the time course for restoration of endothelial dysfunction in the atherosclerotic epicardial coronary arteries in patients with effective lipid-lowering therapy? The intracellular responses to oxidized LDL are so numerous (loss of vasodilation, loss of anticoagulant mechanisms, abnormal inflammation, and growth) that targeting therapies to specific pathways may prove difficult. Parallel efforts in basic physiological and clinical research have resulted in remarkable progress that has improved outcomes in patients with coronary heart disease. We expect that many of the characteristic cell/vessel wall dysfunctions that result from adverse interactions with risk factors are dynamic and can be manipulated in a relatively short time frame. Treatment of atherogenic lipids with other risk factors must be further refined and may well become the cornerstone for effective management of angina, unstable syndromes, and ischemia in addition to the control of important outcomes such as myocardial infarction and coronary death.

Cholesterol, LDL↗

PubMed2003

Human temporomandibular joint disc cartilage as a poroelastic material.

OBJECTIVE: The hypothesis was tested that a poroelastic material model is potentially able to describe the mechanical behavior of cartilaginous tissues in dynamic indentation experiments.Design. This hypothesis was tested by comparing the results from model predictions with results obtained from cyclic indentation experiments. BACKGROUND: The characteristics of cartilaginous tissues in general and of the temporomandibular joint disc in particular are generally identified by static confined or unconfined indentation experiments, while under physiologic circumstances these tissues are mostly loaded dynamically. METHODS: Dynamic indentation experiments were simulated using an axisymmetric finite element model. The results from the simulations were qualitatively compared with the experiments. RESULTS: The simulations showed several similarities with the experiments when the solid matrix was assumed to be hyperelastic. Both the maximum stress and the amount of energy dissipated decreased in each subsequent cycle. Furthermore, a similar dependency on the indentation frequency and amplitude was found. CONCLUSIONS: This qualitative study showed that a poroelastic material model can describe the dynamic behavior of the temporomandibular joint disc, provided that the solid matrix is modeled as hyperelastic. RELEVANCE: Temporomandibular disorders are presumably related to joint load distributions. Besides large static, dynamic loads are considered as a risk factor for cartilaginous wear. Dynamical loads, however, are also considered to stimulate the biosynthetic activity of cartilaginous tissues. Biomechanical analysis can be applied to estimate nonmeasurable joint loads. This enables to understand the underlying mechanisms of temporomandibular disorders, necessary to develop methods to prevent, diagnose and cure joint disorders. The present study shows that a poroelastic material model can be applied successfully to model the dynamical behavior of the temporomandibular joint disc in such analyses.

Cartilage, Articular↗

PubMed1997

Challenges in assessing risk factors in epidemiologic studies on back disorders.

In epidemiologic studies on musculoskeletal disorders, some risk factors, especially physical load, cannot be determined independently from the worker. Posture, movement and external load are the result both of physical work requirements forced on the worker and of the worker's capacity to adopt particular techniques. Risk factors are also adjusted in relation to the worker's health. This paper presents a dynamic model that links exposure to risk factors for back pain and disability. Its aim is to help identify core elements in exposure assessment strategies for epidemiologic studies on back disorders. In this dynamic model, risk factors are determined relative to health status in order to distinguish between etiological and prognostic factors. Measurement techniques for various risk factors are classified into self-reports, observations, and direct instrumentation. Features of commonly used techniques are discussed with respect to feasibility, accuracy, and precision. In addition, consideration is given to the optimum allocation of measurements taking into account the effects of random and systematic variation in exposure due to tasks, workplaces, and workers.

Back Pain↗

PubMed2000

HIV risk and healthcare attitudes among detained adolescents in rural Alabama.

This qualitative study explored the dynamics of adolescent HIV risk through focus group interviews of male and female adolescents at an Alabama juvenile detention facility, key informant interviews, and through interviews of HIV-positive and -negative adults in institutional settings and public health clinics in Alabama. The interviews revealed that commodified or unprotected sex with multiple partners was a common risk activity for male and female adolescents, with a related high risk of sexually transmitted disease. The adolescents were aversive to condom use and lacked knowledge of the dynamics of HIV transmission. Bisexually behaving males who engaged in same-sex prostitution for money or drugs viewed female partners as the source of HIV infection. Illicit drug activity and risky sexual behavior were highly related to economic and status anxiety. Experiences of healthcare were often coercive or were undermined by negative perceptions of health professionals. These negative perceptions and avoidance or lack of access to healthcare compounded the already high risk of sexually transmitted disease for this group of adolescents.

Adolescent↗

PubMed2003

[Glycoprotein 2b3a inhibitors for acute coronary syndromes: what the trials tell us].

Glycoprotein 2b3a inhibitors represent a promising class of antiplatelet medications. Their use in acute coronary syndromes and in patients undergoing percutaneous coronary intervention has been the subject of a number of large controlled trials, including tens of thousands of patients. These trials examined their efficacy, the difference between the various agents, their influence on thrombotic events, whether it is justified to use them in patients with acute coronary syndromes, and the relationship between these medications and early versus aggressive intervention. Platelet GP 2b3a receptor inhibitors seem to have a larger effect in patients who have had a primary coronary intervention than in those with acute coronary syndromes. In patients with acute coronary syndromes, treatment should probably be limited to those considered at high risk: recurrent angina, dynamic ST segment changes, or elevated troponin values. The use of GP2b3a receptor inhibitors during angioplasty and in patients with acute coronary syndromes decreases mortality and the incidence of myocardial infarction, but increases the risk of bleeding.

Acute Disease↗

PubMed2002

An introduction to risk management.

Risk management is formally defined as the process by which an organization assesses and addresses its risks. Historically, the role of risk management has been associated with insurance-buying, occupational safety and health, and legal liability management. In recent years managers and physicians alike have begun to recognize that organizational risks are pervasive, that these risks are extraordinarily diverse and complex, and that these risks are not just confined to "insurable" or accident-related situations. They may include risks arising from actions of regulatory bodies, third party payers, hospitals, partners, and employees, in addition to the physiatrist's personal or business investment, management and clinical practice. Furthermore, changing customer and patient preferences and/or expectations make the assessment of risk an even more dynamic and continuous process. This article describes the formal risk management process and suggests ways that physiatrists can apply risk management to their business and clinical practice. In developing this description, physiatrists and their office managers will learn about the overall goals and objectives of risk management, the challenge of identifying and analyzing risks, the tools and treatment options available, and the means by which risk management efforts are effectively implemented.

Humans↗

PubMed1989

[Clinical, biochemical and anthropometric studies and determination of biological age in relation to body mass in a longitudinal study].

On 46 adipose persons (25 males and 21 females) and 53 test persons with normal weight (35 males and 18 females) at the age of 25-40 years since 1976 clinical, biochemical and anthropometric investigations as well as the determination of the biological age have annually been performed. Several of the parameters established (e.g. cholesterol, triglycerides, fasting blood sugar, blood pressure among others) in the course of 9 years within the well-known normal regions draw towards the adequate valid limit value to the pathological entity. The results of the study distinctly show the central role of obesity for the development of risk factors. Despite the partly only with a certain tendency recognizable behaviour of single parameters after 9 years from our point of view the longitudinal method represents itself as a very well suitable method for establishing dynamic processes and risk factors of age.

Adult↗

PubMed1986

[Relation between obesity and atherogenic risk factors in a longitudinal study].

Since 1980 clinical, biochemical and anthropometric examinations have been performed annually on 46 adipose patients (25 males, 18 females) and 53 test persons (35 males, 18 females) at the age of 25 to 40 years. Several of the established parameters (e. g. cholesterol, triglycerides, uric acid, blood pressure among others) in the course of the 5 years within the known normal regions drew towards the adequate limiting value to the pathological. The results of the study clearly show the central role of the overweight for the formation of risk factors. Despite the partly only in a certain tendency recognizable behaviour of individual signs after 5 years from our point of view the longitudinal technique represents itself as a very well suitable method to realize dynamic processes and risk factors of ageing.

Adult↗

PubMed2006

Early post-phacoemulsification hypotony as a risk factor for intraocular contamination: in vivo model.

PURPOSE: To observe cataract wound dynamics and determine the risk for intraocular contamination under induced conditions of early postoperative hypotony after anterior chamber decompression for high intraocular pressure (IOP) spikes after uneventful phacoemulsification surgery. SETTING: Department of Ophthalmology, Queen's Hospital, Burton-on-Trent, United Kingdom. METHODS: In a prospective case series, 30 patients were treated with anterior chamber decompression for elevated IOP (>35 mm Hg) 1 to 2 hours after uneventful phacoemulsification through clear corneal temporal incisions. A drop of 2% fluorescein was instilled in the conjunctival sac before aqueous release to study the ocular fluid movements during and after the decompression procedure. The patterns of fluorescein movement were observed and photographed under cobalt blue light. RESULTS: Fluorescein staining of the entire corneal tunnel was observed in all 30 eyes after decompression. An immediate fluorescein flare was observed in the anterior chamber after aqueous release in 24 eyes (80%) (P<.001). Observations over several seconds after decompression found a frank influx of fluorescein-stained fluid into the anterior chamber in 12 eyes (40%) (P<.001), giving rise to an "inverse Seidel's test." An intermittent ingress of fluorescein-stained fluid continued for several minutes after the procedure in 6 eyes (20%) (P<.05). CONCLUSIONS: An incompetence of clear corneal cataract wound with intraocular contamination was observed during the period of induced hypotony after anterior chamber decompression in the early post-phacoemulsification period.

Aged↗