Biological Factors (biological + factor)

Distribution by Scientific Domains
Distribution within Medical Sciences


Selected Abstracts


Parallel increase of plasma apoproteins C-II and C-III in Type 2 diabetic patients

DIABETIC MEDICINE, Issue 7 2009
S. Béliard
Abstract Aims, To determine plasma levels of apoprotein (apo) C-II and apoprotein C-III in Type 2 diabetic patients and to examine the clinical and biological factors that are associated with elevated apoC concentrations. Methods, We measured apoC-II and apoC-III in total plasma and in non-high-density lipoprotein fractions by an immunoturbidimetric assay in 88 Caucasian Type 2 diabetic patients and in 138 healthy control subjects. Results, Plasma levels of both apoC-II and apoC-III were increased in Type 2 diabetic patients. The clinical conditions associated with an increase of plasma apoC-II and apoC-III were abdominal obesity, body mass index, poor glycaemic control and lack of insulin treatment. However, when multivariate analysis was used, plasma apoCs levels correlated with triglyceride levels only. The apoC-III/apoC-II ratio was similar in the Type 2 diabetic and control subjects. Conclusions, Our study shows the parallel increase of apoC-II and C-III in Type 2 diabetic patients. This parallel increase is related to hypertriglyceridaemia only. [source]


Spatial autocorrelation of assemblages of benthic invertebrates and its relationship to environmental factors in two upland rivers in southeastern Australia

DIVERSITY AND DISTRIBUTIONS, Issue 5 2005
Natalie J. Lloyd
ABSTRACT The nature of spatial autocorrelation of biota may reveal much about underlying ecological and biological factors responsible for producing those patterns, especially dispersal processes (drift, adult flight, etc.). We report here on assemblage-level autocorrelation in the benthic-invertebrate assemblages (retained in sieves of 300 µm mesh) of riffles in two adjacent, relatively pristine rivers in southeastern Victoria, Australia (40-km reaches of the Wellington and Wonnangatta Rivers). These are related to patterns of autocorrelation in physical and catchment conditions (,environmental variables') in the vicinity of the sampling points. Both the invertebrate assemblages and environmental variables were autocorrelated at small scales (= 8 km) in the Wellington River in one of the sampling years (1996). Dissimilarities of invertebrate assemblages were correlated with dissimilarities of environmental variables in both sampling years (1996 and 1997) in that river. Environmental variables were autocorrelated in the Wonnangatta River, but this was not expressed as autocorrelation in the assemblages of invertebrates, which were not autocorrelated at any scale studied. Individual environmental variables showed different spatial patterns between the two rivers. These results suggest that individual rivers have their own idiosyncratic patterns and one cannot assume that even similar, geographically adjacent rivers will have the same patterns, which is a difficulty for ecological assessment and restoration. [source]


A meta-analysis of trait differences between invasive and non-invasive plant species

ECOLOGY LETTERS, Issue 2 2010
Mark Van Kleunen
Ecology Letters (2010) 13: 235,245 Abstract A major aim in ecology is identifying determinants of invasiveness. We performed a meta-analysis of 117 field or experimental-garden studies that measured pair-wise trait differences of a total of 125 invasive and 196 non-invasive plant species in the invasive range of the invasive species. We tested whether invasiveness is associated with performance-related traits (physiology, leaf-area allocation, shoot allocation, growth rate, size and fitness), and whether such associations depend on type of study and on biogeographical or biological factors. Overall, invasive species had significantly higher values than non-invasive species for all six trait categories. More trait differences were significant for invasive vs. native comparisons than for invasive vs. non-invasive alien comparisons. Moreover, for comparisons between invasive species and native species that themselves are invasive elsewhere, no trait differences were significant. Differences in physiology and growth rate were larger in tropical regions than in temperate regions. Trait differences did not depend on whether the invasive alien species originates from Europe, nor did they depend on the test environment. We conclude that invasive alien species had higher values for those traits related to performance than non-invasive species. This suggests that it might become possible to predict future plant invasions from species traits. [source]


What neurobiology cannot tell us about addiction

ADDICTION, Issue 5 2010
Harold Kalant
ABSTRACT Molecular neurobiological studies have yielded enormous amounts of valuable information about neuronal response mechanisms and their adaptive changes. However, in relation to addiction this information is of limited value because almost every cell function appears to be involved. Thus it tells us only that neurons adapt to ,addictive drugs' as they do to all sorts of other functional disturbances. This information may be of limited help in the development of potential auxiliary agents for treatment of addiction. However, a reductionist approach which attempts to analyse addiction at ever finer levels of structure and function, is inherently incapable of explaining what causes these mechanisms to be brought into play in some cases and not in others, or by self-administration of a drug but not by passive exposure. There is abundant evidence that psychological, social, economic and specific situational factors play important roles in initiating addiction, in addition to genetic and other biological factors. Therefore, if we hope to be able to make predictions at any but a statistical level, or to develop effective means of prevention, it is necessary to devise appropriate integrative approaches to the study of addiction, rather than pursue an ever-finer reductive approach which leads steadily farther away from the complex interaction of drug, user, environment and specific situations that characterizes the problem in humans. [source]


Fate of Pesticides in the Environment and its Bioremediation

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2005
M. Gavrilescu
Abstract The present paper is an overview of the presence and fate of pesticides as persistent organic pollutants in the environment as well as of the potential for their detoxification, also combined with chemical and physical treatment. It contains information gathered from a range of currently available sources. The fate of pesticides in the environment is analyzed considering the processes that determine their persistence and mobility, grouped into transport, transfer and transformation processes. Few pesticide characteristics such as persistence, mobility and biodegradability are emphasized. The fate of a pesticide and the potential for its persistence and mobility from the site of application are considered to be affected by the chemical and physical properties of the pesticide, site characteristics such as soil and groundwater individuality, climate and local weather conditions, biological population, and the handling practices of the pesticide user. Bioremediation, as one of the most environmentally-sound and cost-effective methods for the decontamination and detoxification of a pesticide-contaminated environment is discussed especially considering the factors affecting the biodegradability of pesticides such as biological factors and the characteristics of the chemical compounds. In situ and ex situ bioremediation as possible types of bioremediation activities are weighted up. Also, the paper includes some considerations for developing strategies regarding the choice of bioremediation technology, as well as advantages and disadvantages of the bioremediation of environmental components polluted with pesticides. [source]


REVIEW: Modeling stress and drug craving in the laboratory: implications for addiction treatment development

ADDICTION BIOLOGY, Issue 1 2009
Rajita Sinha
ABSTRACT Addition is a chronic relapsing illness affected by multiple social, individual and biological factors that significantly impact course and recovery of the illness. Stress interacts with these factors and increases addiction vulnerability and relapse risk, thereby playing a significant role in the course of the illness. This paper reviews our efforts in developing and validating laboratory models of stress and drug cue-related provocation to assess stress responses and stress-related adaptation in addicted individuals compared with healthy controls. Empirical findings from human laboratory and brain imaging studies are presented to show the specific stress-related dysregulation that accompanies the drug-craving state in addicted individuals. In order to adequately validate our laboratory model, we have also carefully examined relapse susceptibility in the addicted individuals and these data are reviewed. The overarching goal of these efforts is to develop a valid laboratory model to identify the stress-related pathophysiology in addiction with specific regard to persistent craving and compulsive seeking. Finally, the significant implications of these findings for the development of novel treatment interventions that target stress processes and drug craving to improve addiction relapse outcomes are discussed. [source]


Personality, gender, and crying

EUROPEAN JOURNAL OF PERSONALITY, Issue 1 2001
Mathell Peter
This study examined gender differences in crying as well as associations between basic personality traits and self-reported indices of crying. Forty-eight men and 56 women completed the Five-Factor Personality Inventory and the Adult Crying Inventory. Substantial gender differences were demonstrated in crying frequency and crying proneness, but not with respect to mood changes after crying. As predicted, women reported a higher frequency of crying and more proneness to cry both for negative and positive reasons. For women, all these crying indices were negatively associated with Emotional Stability. For men, only a significant negative relationship between Emotional Stability and crying for negative reasons emerged. No clear links were found between personality and mood changes after crying. Multiple regression analysis revealed a significant predictive role of gender for crying proneness, even when controlling for personality differences, but not for crying frequency. Adding personality by gender interaction terms resulted in a disappearance of the main effect of sex, while significant interactions with personality factors showed up for crying frequency and general crying proneness. It is suggested that future research on the relationship between personality and crying should focus more on the underlying mechanisms of observed relationships. Furthermore, it is recommended that future research should examine the role of different emotion regulation strategies. In addition, biological factors, temperament, upbringing measures, and socio-demographic variables should be taken into account. Copyright © 2001 John Wiley & Sons, Ltd. [source]


THE COMBINED EFFECTS OF RIVERS AND REFUGIA GENERATE EXTREME CRYPTIC FRAGMENTATION WITHIN THE COMMON GROUND SKINK (SCINCELLA LATERALIS)

EVOLUTION, Issue 2 2010
Nathan D. Jackson
Rivers can act as both islands of mesic refugia for terrestrial organisms during times of aridification and barriers to gene flow, though evidence for long-term isolation by rivers is mixed. Understanding the extent to which riverine barrier effects can be heightened for populations trapped in mesic refugia can help explain maintenance and generation of diversity in the face of Pleistocene climate change. Herein, we implement phylogenetic and population genetic approaches to investigate the phylogeographic structure and history of the ground skink, Scincella lateralis, using mtDNA and eight nuclear loci. We then test several predictions of a river,refugia model of diversification. We recover 14 well-resolved mtDNA lineages distributed east,west along the Gulf Coast with a subset of lineages extending northward. In contrast, ncDNA exhibits limited phylogenetic structure or congruence among loci. However, multilocus population structure is broadly congruent with mtDNA patterns and suggests that deep coalescence rather than differential gene flow is responsible for mtDNA,ncDNA discordance. The observed patterns suggest that most lineages originated from population vicariance due to riverine barriers strengthened during the Plio,Pleistocene by a climate-induced coastal distribution. Diversification due to rivers is likely a special case, contingent upon other environmental or biological factors that reinforce riverine barrier effects. [source]


Survival of Escherichia coli O157:H7 in private drinking water wells: influences of protozoan grazing and elevated copper concentrations

FEMS MICROBIOLOGY LETTERS, Issue 1 2002
Rebekka R.E Artz
Abstract The survival characteristics of Escherichia coli O157:H7 in private drinking water wells were investigated to assess the potential for human exposure. A non-toxigenic, chromosomally lux -marked strain of E. coli O157:H7 was inoculated into well water from four different sites in the North East of Scotland. These waters differed significantly in their heavy metal contents as well as nutrient and bacterial grazer concentrations. Grazing and other biological factors were studied using filtered (3 and 0.2 ,m) and autoclaved water. The survival of E. coli O157:H7 was primarily decreased by elevated copper concentrations. This hypothesis was supported by acute toxicity assay data. In addition, significant protozoan predation effects were observed in untreated water when compared with survival rates in filtered water. The combination of these two factors in particular determines the survival time of the pathogen in a private water well. It therefore appears that wells with higher water quality as assessed using the European Union Drinking Water Directive standards will also allow survival of E. coli O157:H7 for much longer periods. [source]


Evidence that viral abundance across oceans and lakes is driven by different biological factors

FRESHWATER BIOLOGY, Issue 6 2008
JESSICA L. CLASEN
Summary 1. Samples from 16 lakes in central (n = 145) and western (n = 12) North America, the coastal northeast Pacific (n = 302) and the western Canadian Arctic Oceans (n = 142) were collected and analysed for viral, bacterial and cyanobacterial abundances and chlorophyll- a concentration. 2. Viral abundance was significantly different among the environments. It was highest in the coastal Pacific Ocean and lowest in the coastal Arctic Ocean. The abundances of bacteria and cyanobacteria as well as chlorophyll- a concentrations also differed significantly among the environments, with both bacterial abundance and chlorophyll- a concentration highest in lakes. As a consequence, the association of these variables with viral abundance varied among the environments. 3. Discriminant analyses with the abundance data indicated that the marine and freshwater environments were predictably different from each other. Multiple-regression analysis included bacterial and cyanobacterial abundances, and chlorophyll- a concentration as significant variables in explaining viral abundance in lakes. In regression models for the coastal Pacific Ocean, bacterial and cyanobacterial abundances were significant variables, and for the coastal Arctic Ocean viral abundance was predicted by bacterial abundance and chlorophyll- a concentration. 4. The relationship of viral and bacterial abundance differed between the investigated freshwater and marine environments, probably because of differences in viral production and loss rates. However, freshwaters had fewer viruses compared to bacteria, despite previously documented higher burst sizes and frequencies of infected cells, suggesting that loss rates may be more important in lakes. 5. Together, these findings suggest that there are different drivers of viral abundance in different aquatic environments, including lakes and oceans. [source]


Neoplastic development in plasma cells

IMMUNOLOGICAL REVIEWS, Issue 1 2003
Michael Potter
Summary:, An increasing number of model systems of plasma cell tumor (PCT) formation have been and are being developed. Discussed here are six models in mice and multiple myeloma (MM) in humans. Each model illustrates a unique set of biological factors. There are two general types of model systems: those that depend upon naturally arising mutagenic changes (pristane-induced PCTs, 5TMM, and MM) and those that are associated with oncogenes (Eµ-v-abl), growth factors [interleukin-6 (IL-6)], and anti-apoptotic factors (Bcl-xL/Bcl-2). PCTs develop in several special tissue microenvironments that provide essential cytokines (IL-6) and cell,cell interactions. In mice, the activation and deregulation of c-myc by chromosomal translocations is a major feature in many of the models. This mechanism is much less a factor in MM and the 5T model in mice. Genetically determined susceptibility is involved in many of the mouse models, but only a few genes have been implicated thus far. [source]


A Pain Severity,Hypothalamic,Pituitary,Adrenocortical Axis Interaction: The Effects on Pain Pathways,

JOURNAL OF APPLIED BIOBEHAVIORAL RESEARCH, Issue 1 2007
John P. Garofalo
Recent efforts have identified psychosocial and biological factors influencing the pathogenesis of chronic pain. The present study attempted to identify whether these two variables interact and, in turn, represent an underlying mechanism in the transition from acute to chronic pain. Salivary cortisol samples were collected upon waking up and 20 minutes later daily for 2 weeks from acute pain patients. Analyses revealed a direct relationship between pain severity and hypothalamic,pituitary,adrenocortical activity for temporomandibular disorder, and a negative relationship between these variables for low back pain populations. These results highlight the possible interaction between neuroendocrine and psychological factors to increase the risk for chronic pain. [source]


Investigation of critical inter-related factors affecting the efficacy of pulsed light for inactivating clinically relevant bacterial pathogens

JOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2010
H.P. Farrell
Abstract Aims:, To investigate critical electrical and biological factors governing the efficacy of pulsed light (PL) for the in vitro inactivation of bacteria isolated from the clinical environment. Development of this alternative PL decontamination approach is timely, as the incidence of health care,related infections remains unacceptably high. Methods and Results:, Predetermined cell numbers of clinically relevant Gram-positive and Gram-negative bacteria were inoculated separately on agar plates and were flashed with ,60 pulses of broad-spectrum light under varying operating conditions, and their inactivation measured. Significant differences in inactivation largely occurred depending on the level of the applied lamp discharge energy (range 3·2,20 J per pulse), the amount of pulsing applied (range 0,60 pulses) and the distance between light source and treatment surface (range 8,20 cm) used. Greater decontamination levels were achieved using a combination of higher lamp discharge energies, increased number of pulses and shorter distances between treatment surface and the xenon light source. Levels of microbial sensitivity also varied depending on the population type, size and age of cultures treated. Production of pigment pyocynanin and alginate slime in mucoid strains of Pseudomonas aeruginosa afforded some protection against lethal action of PL; however, this was evident only by using a combination of reduced amount of pulsing at the lower lamp discharge energies tested. A clear pattern was observed where Gram-positive bacterial pathogens were more resistant to cidal effects of PL compared to Gram negatives. While negligible photoreactivation of PL-treated bacterial strains occurred after full pulsing regimes at the different lamp discharge energies tested, some repair was evident when using a combination of reduced pulsing at the lower lamp discharge energies. Strains harbouring genes for multiple resistances to antibiotics were not significantly more resistant to PL treatments. Slight temperature rises (,4·2°C) were measured on agar surfaces after extended pulsing at higher lamp discharge energies. Presence of organic matter on treatment surface did not significantly affect PL decontamination efficacy, nor did growth of PL-treated bacteria on selective agar diminish survival compared to similarly treated bacteria inoculated and enumerated on nonselective agar plates. Conclusions:, Critical inter-related factors affecting the effective and repeatable in vitro decontamination performance of PL were identified during this study that will aid further development of this athermal process technology for applications in health care and in industry. Very rapid reductions (c. 7 log10 CFU cm,2 within ,10 pulses) occurred using discharge energy of 20 J for all tested clinically relevant bacteria under study when treated at 8 cm distance from xenon light source. While no resistant flora is expected to develop for treatment of microbial pathogens on two-dimensional surfaces, careful consideration of scale up factors such as design and operational usage of this PL technique will be required to assure operator safety. Significance and Impact of the Study:, Findings and conclusions derived from this study will enable further development and optimization of this decontamination technique in health care and in food preparation settings, and will advance the field of nonthermal processing technologies. [source]


Sexual Differentiation of Behaviour in Monkeys: Role of Prenatal Hormones

JOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2009
K. Wallen
The theoretical debate over the relative contributions of nature and nurture to the sexual differentiation of behaviour has increasingly moved towards an interactionist explanation that requires both influences. In practice, however, nature and nurture have often been seen as separable, influencing human clinical sex assignment decisions, sometimes with disastrous consequences. Decisions about the sex assignment of children born with intersex conditions have been based almost exclusively on the appearance of the genitals and how other's reactions to the gender role of the assigned sex affect individual gender socialisation. Effects of the social environment and gender expectations in human cultures are ubiquitous, overshadowing the potential underlying biological contributions in favour of the more observable social influences. Recent work in nonhuman primates showing behavioural sex differences paralleling human sex differences, including toy preferences, suggests that less easily observed biological factors also influence behavioural sexual differentiation in both monkeys and humans. We review research, including Robert W. Goy's pioneering work with rhesus monkeys, which manipulated prenatal hormones at different gestation times and demonstrated that genital anatomy and specific behaviours are independently sexually differentiated. Such studies demonstrate that, for a variety of behaviours, including juvenile mounting and rough play, individuals can have the genitals of one sex but show the behaviour more typical of the other sex. We describe another case, infant distress vocalisations, where maternal responsiveness is best accounted for by the mother's response to the genital appearance of her offspring. Taken together, these studies demonstrate that sexual differentiation arises from complex interactions where anatomical and behavioural biases, produced by hormonal and other biological processes, are shaped by social experience into the behavioural sex differences that distinguish males and females. [source]


Making sex: law's narratives of sex, gender and identity

LEGAL STUDIES, Issue 1 2003
Laura Grenfell
From the 1970 decision of Corbett, onwards, legal narratives established two modes of categorising complex social identi5 in relation to sex and gender. These narratives responded to complex identity questions by attempting to simplify identity by limiting it to biological factors or anatomical and psychological factors. I demonstrate that the law's struggle to ,make' sex is reflected to a certain extent by feminism's trajectory, in that feminisms have also attempted to grapple with these complex questions, and often opted for the same simple solutions to the problem of understanding gender, sex and identity. The aim of this paper is to show that some strands of feminist theory, specifically post-structuralist feminist theory, can produce a more progressive and constructive approach to determining sex in their ability to illuminate the complexities of identity. In particular, my aim is to urge those courts that ,make' sex to consider these complexities and the implications that flow from placing transgender people into rigid arid narrow categories. [source]


Nurture: The Fundamental Significance of Relationship as a Paradigm for Mental Health Nursing

PERSPECTIVES IN PSYCHIATRIC CARE, Issue 3 2003
Bonnie Raingruber PhD
TOPIC Whether nature or nurture is the most appropriate paradigm for mental health nursing practice, education, and research. PURPOSE To present detailed information that nurture is the most inclusive and sustaining paradigm for mental health nursing. SOURCES Published literature. CONCLUSIONS Psychological, social, cultural, environmental, biological, and experience-based problems are the root of mental illness. Mental health nursing must have a comprehensive paradigm that honors the relational nature of the nurse-patient relationship, the critical influence of environment, the importance of biological factors, and the way that narrative understanding and history shape behavior. [source]


Causes of Male Excess Mortality: Insights from Cloistered Populations

POPULATION AND DEVELOPMENT REVIEW, Issue 4 2003
Marc Luy
The degree to which biological factors contribute to the existence and the widening of mortality differences by sex remains unclear. To address this question, a mortality analysis for the years 1890 to 1995 was performed comparing mortality data on more than 11,000 Catholic nuns and monks in Bavarian communities living in very nearly identical behavioral and environmental conditions with life table data for the general German population. While the mortality differences between women and men in the general German population increased considerably after World War II, they remained almost constant among the members of Bavarian religious orders during the entire observation period, with slight advantages for nuns. Thus, the higher differences observable in the general population cannot be attributed to biological factors. The different trends in sex-specific mortality between the general and the cloistered populations are caused exclusively by men in the general population who were unable to follow the trend in mortality reduction of women, nuns, and especially monks. Under the special environmental conditions of nuns and monks, biological factors appear to confer a maximum survival advantage for women of no more than one year in remaining life expectancy at young adult ages. [source]


Research Review: Crossing syndrome boundaries in the search for brain endophenotypes

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2009
Yonata Levy
The inherent imprecision of behavioral phenotyping is the single most important factor contributing to the failure to discover the biological factors that are involved in psychiatric and neurodevelopmental disorders (e.g., Bearden & Freimer, 2006). In this review article we argue that in addition to an appreciation of the inherent complexity at the biological level, a rather urgent task facing behavioral scientists involves a reconsideration of the role that clinical syndromes play in psychological theorizing, as well as in research into the biological basis of cognition and personality. Syndrome heterogeneity, cross-syndrome similarities and syndrome comorbidities question the relevance of syndromes to biological research. It is suggested that the search for brain endophenotypes, intermediate between genes and behavior, should be based on cross-syndrome, trait classification. Cohort selection should rest on behavioral homogeneity, enabling, when necessary, syndrome heterogeneity. [source]


Specific reading disability (dyslexia): what have we learned in the past four decades?

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 1 2004
Frank R. Vellutino
We summarize some of the most important findings from research evaluating the hypothesized causes of specific reading disability (,dyslexia') over the past four decades. After outlining components of reading ability, we discuss manifest causes of reading difficulties, in terms of deficiencies in component reading skills that might lead to such difficulties. The evidence suggests that inadequate facility in word identification due, in most cases, to more basic deficits in alphabetic coding is the basic cause of difficulties in learning to read. We next discuss hypothesized deficiencies in reading-related cognitive abilities as underlying causes of deficiencies in component reading skills. The evidence in these areas suggests that, in most cases, phonological skills deficiencies associated with phonological coding deficits are the probable causes of the disorder rather than visual, semantic, or syntactic deficits, although reading difficulties in some children may be associated with general language deficits. Hypothesized deficits in general learning abilities (e.g., attention, association learning, cross-modal transfer etc.) and low-level sensory deficits have weak validity as causal factors in specific reading disability. These inferences are, by and large, supported by research evaluating the biological foundations of dyslexia. Finally, evidence is presented in support of the idea that many poor readers are impaired because of inadequate instruction or other experiential factors. This does not mean that biological factors are not relevant, because the brain and environment interact to produce the neural networks that support reading acquisition. We conclude with a discussion of the clinical implications of the research findings, focusing on the need for enhanced instruction. [source]


REVIEW ARTICLE: HIV Infection in the Female Genital Tract: Discrete Influence of the Local Mucosal Microenvironment

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2010
Charu Kaushic
Citation Kaushic C, Ferreira VH, Kafka JK, Nazli A. HIV infection in the female genital tract: discrete influence of the local mucosal microenvironment. Am J Reprod Immunol 2010 Women acquire HIV infections predominantly at the genital mucosa through heterosexual transmission. Therefore, the immune milieu at female genital surfaces is a critical determinant of HIV susceptibility. In this review, we recapitulate the evidence suggesting that several distinctive innate immune mechanisms in the female genital tract (FGT) serve to significantly deter or facilitate HIV-1 infection. Epithelial cells lining the FGT play a key role in forming a primary barrier to HIV entry. These cells express Toll-like receptors and other receptors that recognize and respond directly to pathogens, including HIV-1. In addition, innate biological factors produced by epithelial and other cells in the FGT have anti-HIV activity. Female sex hormones, co-infection with other pathogens and components in semen may also exacerbate or down-modulate HIV transmission. A combination of innate and adaptive immune factors and their interactions with the local microenvironment determine the outcome of HIV transmission. Improving our understanding of the female genital microenvironment will be useful in developing treatments that augment and sustain protective immune responses in the genital mucosa, such as microbicides and vaccines, and will provide greater insight into viral pathogenesis in the FGT. [source]


Frequency and Localization of the Putative Vomeronasal Organ in Humans in Relation to Age and Gender,

THE LARYNGOSCOPE, Issue 3 2001
Michael Knecht MD
Abstract Objectives/Hypotheses In many species the vomeronasal organ (VNO) serves as a chemosensory organ in addition to the olfactory system. The present investigation was undertaken to study 1) the frequency of monolateral or bilateral detection of the putative VNO (pVNO) in humans, 2) its localization in humans, and 3) whether detectability of the pVNO varies with age or gender. Study Design Prospective. Methods A total of 173 subjects participated in this study (88 women and 85 men; age range, 2,91 y). Inspection of the nose was performed with a speculum and a 30° endoscope. The exact localization of the VNO was measured with custom-built rulers. Results The study revealed the following major results: 1) A pVNO is detectable in approximately two-thirds of the population and bilateral pVNOs are present in approximately 40% of investigated subjects, 2) its localization on the left and right nasal septum is almost symmetrical, and 3) and detectability of the pVNO is not related to age or gender. Conclusions The present data indicated that the pVNO is present in approximately two-thirds of the population. This value may be biased by methodological or biological factors; nevertheless, it indicates that the pVNO is not observed in all humans regardless of age and gender. Thus, considering its variability in shape and immunohistochemical characteristics and the missing nerval connections between the peripheral "organ" and the central nervous system, the present results are not suited to argue for a functional significance of the pVNO in humans. [source]


Is there a relationship between skin erythema and fatigue in women undergoing irradiation after breast conserving surgery for early breast cancer?

ASIA-PACIFIC JOURNAL OF CLINICAL ONCOLOGY, Issue 4 2009
A prospective study
Abstract Aim: A prospective study was conducted to determine whether any relationship exits between skin erythema, fatigue and biological factors during and after adjuvant radiotherapy for early breast cancer. Methods: Breast erythema was assessed objectively using reflectance spectrophotometry. Fatigue was recorded utilising the functional assessment of cancer therapy fatigue subscale. A number of potential systemic indicators (biological factors) of the effects of radiotherapy was measured, including circulating cytokines, coagulation factors, peripheral blood indices and biochemistry. Measurements for erythema, fatigue and biological factors were taken at baseline and intervals during and following completion of radiotherapy. Results: A total of 52 eligible patients was included in the analysis. Breast erythema was shown to progressively increase during treatment, peaking on day 36 and returning to baseline by 4 months post-irradiation. Fatigue also progressively increased during treatment, reaching a plateau between day 22 and 2 weeks post-radiotherapy. A statistically significant association was demonstrated between total breast erythema and fatigue at days 4, 8, 22 and 29 of irradiation and 2 and 6 weeks post-radiotherapy. When only the increase in erythema attributable to radiotherapy was considered, statistically significant associations remained for day 4 of irradiation and 2 and 6 weeks post-radiotherapy. When multiple time points were considered together, an association between increased erythema and fatigue was present only post-radiotherapy. No relationship was demonstrated between the biological factors and erythema or fatigue during radiotherapy. Conclusion: This study demonstrates a significant and consistent relationship between radiotherapy-induced breast erythema and fatigue, particularly in the period immediately following breast irradiation. [source]


Biological and environmental factors controlling root dynamics and function: effects of root ageing and soil moisture

AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2010
L.H. COMAS
Abstract Understanding factors controlling root dynamics and functioning can lead to more efficient and profitable vineyard management. However, our current understanding of root dynamics and their regulation by plant and environmental factors is limited, particularly under field conditions. This paper presents current understanding of grape root dynamics, highlighting studies using minirhizotron cameras, which directly assess root dynamics, and experiments on roots of known age, which link root phenology and function. Data summarised here show timing of grape root production varies widely among different regions, as well as among rootstocks and canopy management systems in the same region. Timing of production can be responsive to differences in soil moisture. Lifespan of grape roots, however, appears less affected by soil moisture because of nocturnal hydraulic redistribution. Root function, such as capacity for P and N uptake, declines rapidly with root age. Differences in timing and spatial distribution of root production can effect above-ground growth and vineyard water-use efficiency. Improving our understanding of when roots grow and are functionally active in agricultural systems can lead to improved water and fertiliser applications, and more precise vineyard management. Because both environmental and biological factors affect root dynamics, simple predictions of timing of root production or standing populations with shoot development are unlikely to be achieved. However, with multi-year data on root dynamics, and environmental and biological factors, regionally specific models of root populations and their functioning may be possible to develop. [source]


High dose methotrexate population pharmacokinetics and Bayesian estimation in patients with lymphoid malignancy

BIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 8 2009
Ye Min
Abstract The purpose of present study was to develop a population pharmacokinetic model of high dose methotrexate (HD-MTX) infusion in patients with lymphoid malignancy, to investigate the biological and clinical covariates related to the drug distribution and elimination. It is also the purpose to propose a limited sampling strategy (LSS) for the estimation of the time above the threshold (0.2,µmol·L,1). A total 82 patients with lymphoid malignancy were involved in the study. A pharmacokinetic model was developed using nonlinear mixed-effect model. The influence of demographic characteristics, biological factors, and concurrent administration were investigated. The final predictive performance was validated by bootstrap and cross-validation. Bayesian estimation was evaluated. The pharmacokinetics of HD-MTX was described by a two-compartment model. The pharmacokinetic parameters and the inter-individual variability were as follows: the clearance CL, 7.45,L·h,1 (inter-individual variability 50.6%), the volume of the central and peripheral compartment V1, 25.9,L (22.5%), V2, 9.23,L (97.8%), respectively, and the intercompartmental clearance Q, 0.333,L·h,1 (70.4%). The influence of serum creatinine on CL and weight on V1 was retained in the final model. The protocol involved one sampling time at 44,h after the start of the infusion, allowing one to predict the time at which the MTX concentration reached the expected threshold (0.2,µmol·L,1). Serum creatinine and weight showed significant influence on methotrexate CL and V1, respectively. Furthermore, a Bayesian estimation based on the covariates and 44,h sample was developed, allowing prediction of the individual methotrexate pharmacokinetic parameters and the time to 0.2,µmol·L,1. Copyright © 2009 John Wiley & Sons, Ltd. [source]


Prediction of the response to chemoradiation and prognosis in oesophageal squamous cancer

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 5 2002
K. Kishi
Background: The sensitivity of cancer cells to chemotherapy and radiation therapy depends on various biological properties. This study investigated the expression of p53, CDC25B and metallothionein (MT), and evaluated their clinical significance in chemoradiation therapy (CRT) for oesophageal squamous cell carcinoma. Methods: The expression of p53, CDC25B and MT was evaluated by immunohistochemistry using biopsy specimens taken before CRT for 77 patients with oesophageal squamous cell carcinoma, and correlated with the pathological effects of CRT and survival. Results: p53-positive tumours and MT-positive tumours had a poor response to CRT, whereas tumours with strong CDC25B expression were associated with a good response. When each patient was scored for the presence of the three biological factors, there was a strong correlation between the sensitivity score and the pathological effect of CRT (P < 0·001), and a (non-significant) difference in the 5-year survival rate between patients with a high score and those with a low score (67 versus 34 per cent respectively; P = 0·12). Conclusion: The combined evaluation of p53, CDC25B and MT may help to identify patients with advanced oesophageal squamous cell carcinoma who will benefit from preoperative CRT. © 2002 British Journal of Surgery Society Ltd [source]


Role of surgical outcome as prognostic factor in advanced epithelial ovarian cancer: A combined exploratory analysis of 3 prospectively randomized phase 3 multicenter trials

CANCER, Issue 6 2009
By the Arbeitsgemeinschaft Gynaekologische Onkologie Studiengruppe Ovarialkarzinom (AGO-OVAR), the Groupe d'Investigateurs Nationaux Pour les Etudes des Cancers de l'Ovaire (GINECO)
Abstract BACKGROUND: Primary surgery followed by platinum-taxane based chemotherapy has been the standard therapy in advanced ovarian cancer. However, the prognostic role of complete and so-called optimal and suboptimal debulking and its interaction with biological factors has not been not fully defined. METHODS: Exploratory analysis was conducted of 3 prospective randomized trials (AGO-OVAR 3, 5, and 7) investigating platinum-taxane based chemotherapy regimens in advanced ovarian cancer conducted between 1995 and 2002. RESULTS: A total of 3126 patients were analyzed. Approximately one-third each fulfilled criteria for complete resection (group A), small residual tumor burden of 1-10 mm (group B), or macroscopic residual disease exceeding 1 cm in diameter (group C). Multivariate analysis showed improved progression-free and overall survival for group A with complete resection compared with groups B or C (P < .0001). The impact of so-called optimal debulking as in group B showed a smaller prognostic impact compared with group C. Further independent prognostic factors for overall survival were age, performance status, grade, FIGO stage, and histology, namely the mucinous subtype. An interaction between residual tumor and some biologic factors was demonstrated. CONCLUSIONS: The goal of primary surgery should be complete resection. The prognostic impact of tumor biology seemed to be partially overruled by residual tumor and further evaluation of biologic factors should stratify for residual tumor. Cancer 2009. © 2009 American Cancer Society. [source]


Comparison between differentcell kinetic variables in human breast cancer

CELL PROLIFERATION, Issue 2 2000
F. Barzanti
Cell kinetics holds a prominent role among biological factors in predicting clinical outcome and response to treatment in neoplastic patients. Different cell kinetic variables are often considered as valid alternatives to each other, but the limited size of case series analysed in several studies and the lack of simultaneous determinations of all the variables on the same tumours do not justify this conclusion. In the present study, the correlation between [3H]thymidine labelling index ([3H]dT LI), flow cytometric S phase cell fraction (FCM-S) and Ki-67 immunoreactivity (Ki-67/MIB-1) was verified and the type of correlation with the most important clinical, pathological and biological patient and tumour characteristics was investigated in a very large series of breast cancer patients. Ki-67/MIB-1, FCM-S and [3H]dT LI were determined in 609, 526 and 485 patients, respectively, and all three cell proliferation indices were evaluated in parallel on the same tumour in a series of 330 breast cancer patients. All the cell kinetic determinations were performed within the context of National Quality Control Programmes. Very poor correlation coefficients (ranging from 0.37 to 0.18) were observed between the different cell kinetic variables determined in parallel on the same series of breast cancers. Moreover, Ki-67/MIB-1 and FCM-S showed a significant relationship with histological type, grade and tumour size, whereas statistically significant correlations were not observed for [3H]dT LI. In conclusion, the results show that the different cell kinetic variables provide different biological information and cannot be considered as alternatives to each other. [source]


Der globale Kohlenstoffkreislauf im Anthropozän.

CHEMIE IN UNSERER ZEIT (CHIUZ), Issue 2 2010
Betrachtung aus meereschemischer Perspektive
Abstract Durch die Verbrennung fossiler Brennstoffe werden durch die Menschheit jährlich über 8 Milliarden Tonnen Kohlenstoff (Gt C) in Form von CO2 in die Atmosphäre emittiert. Die kumulativen Emissionen seit Beginn der industriellen Revolution haben zu einem Anstieg der atmosphärischen CO2 -Konzentration geführt, die einen zusätzlichen anthropogenen Treibhauseffekt zur Folge hat. Von den drei auf der Zeitskala von Jahrhunderten austauschenden Kohlenstoffreservoiren Atmosphäre, terrestrische Biosphäre und Ozean ist der Ozean bei weitem das größte. Das CO2 -System des Meerwassers umfasst die chemischen Spezies HCO3,, CO32, und CO2(aq). Daraus resultiert die pH-puffernde Eigenschaft des Meerwassers sowie seine hohe Aufnahmekapazität für anthropogenes CO2. Mit Hilfe von vier chemischen Messgrößen kann das marine CO2 -System analytisch sehr präzise beschrieben werden. Diese Messgrößen dienen als sensitive "Sensoren" für physikalische, chemische und biologische Vorgänge im Meer. Im marinen Kohlenstoffkreislauf sind größere natürliche Prozesse aktiv, die Kohlenstoff mit der Atmosphäre austauschen und im Innern der Ozeans umverteilen. Diese Prozesse werden auch als "Pumpen" bezeichnet und sowohl durch physikalische als auch biologische Faktoren angetrieben. Während die "physikalische Pumpe" unmittelbar durch die Aufnahme von anthropogenem CO2 aus der Atmosphäre verstärkt wird, ist dieses für die beiden "biologischen Pumpen" bisher ungeklärt. Eine Vielzahl von potenziellen Konsequenzen des globalen Wandels (Temperaturanstieg, marine CO2 -Aufnahme, Ozeanversauerung) auf marine Ökosysteme sind identifiziert worden. Diese werden gegenwärtig intensiv hinsichtlich ihrer Klimasensitivität sowie ihres Rückkopplungspotenzials auf das Klima untersucht. Es ist jedoch kaum vorstellbar, dass die "biologischen Pumpen" sich unter dem Einfluss des globalen Wandels nicht verändern werden. By burning of fossil fuels humankind emits more than 8 billion tons of carbon (Gt C) in the form of CO2 to the atmosphere. Since the onset of the industrial revolution the cumulative emissions have led to an increase of the atmospheric CO2 concentration which corresponds to an additional radiative forcing in the atmosphere. Of the three reservoirs which exchange carbon on the time scale of centuries , atmosphere, terrestrial biosphere, and ocean , the ocean is by far the largest. The marine CO2 system comprises the chemical species HCO3,, CO32,, and CO2(aq). This gives rise to the pH-buffering nature of seawater as well as its high uptake capacity for anthropogenic CO2. Four measurement parameters of the marine CO2 system are available for an accurate analytical characterization. These parameters also provide a means of sensing the role of physical, chemical, and biological drivers for the marine carbon cycle. The marine carbon cycle features major natural processes that exchange carbon with the atmosphere and re-distribute it throughout the ocean. These are known as "pumps" and driven by physical and biological factors. While the "physical pump" is inevitably enhanced by the oceanic uptake of anthropogenic CO2, even the sign of the response is currently not clear for the "biological pumps". A host of potential consequences of global change (temperature rise, ocean carbonation, ocean acidification) have been identified. These are currently studied intensively with respect to their climate sensitivity as well as the climate feedback potential. [source]


Seasonal variation and meteotropism in suicide: clinical relevance of findings and implications for research

ACTA NEUROPSYCHIATRICA, Issue 1 2002
A. Preti
Seasonal asymmetry in yearly suicide occurrence is a long-observed phenomenon in psychiatric, suicidological and sociological research, and the effects of seasonal factors on suicidal behaviour have been the focus of a number of earlier studies. Taking into account limitations of data and methods, these studies have in general favoured interpretations based on psychosocial factors. Recent studies have challenged the widely held notion that seasonal effects on suicide are not influenced by age, gender or the circumstances of the act. The suicides committed with violent methods have been shown to follow clearer seasonal patterns than suicides by less violent methods, and differences have been found between male and female cycles of occurrence. The seasonal occurrence of suicides has also been found to differ significantly between the young and the elderly. The use of inappropriate statistics or age- and gender-biased samples may have hidden a seasonal component in some previous studies on attempted suicide. The absence of seasonality in earlier studies on attempted suicide was interpreted as depending upon the minor relevance of psychiatric and biological factors in non-fatal self-harm. However, recent studies have reported clear seasonality in attempted suicide samples, with older people showing greater seasonal effect. Recent literature after 1985 on seasonal variation and weather or climate influence in attempted and completed suicide is reviewed. Suggestions for research and the development of more effective preventative strategies are offered. [source]


Planar Asymmetry Tips the Phonological Playground and Environment Raises the Bar

CHILD DEVELOPMENT, Issue 4 2001
Mark A. Eckert
Reading readiness varies as a function of family and environmental variables. This study of 11-year-old children (N=39) was designed to determine if there was an additional or interactive contribution of brain structure. Evidence is presented that both environmental and biological variables predict phonological development. Temporal lobe (planar) asymmetry, hand preference, family history of reading disability, and SES explained over half of the variance in phonological and verbal performance. The results demonstrate a linear association between cerebral organization and phonological skill within socioeconomic groups. These data provide concrete evidence to support the commonly held assumption that both environmental and biological factors are independent determinants of a child's ability to process linguistic information. [source]