scholarly journals Epidemiological Studies on Physical, Chemical, Zoonotic and Psychological Hazards among Veterinarians

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tanuja Parmar
Keyword(s):  
Epidemiological Studies ◽  
Physical Chemical

scholarly journals What Can Chemical Carcinogenesis Shed Light on the LNT Hypothesis in Radiation Carcinogenesis?

Dose-Response ◽  
2019 ◽  
Vol 17 (3) ◽  
pp. 155932581987679
Author(s):  
James E. Trosko
Keyword(s):  
Chemical Carcinogenesis ◽  
Epidemiological Studies ◽  
Invasion And Metastasis ◽  
Radiation Carcinogenesis ◽  
Scientifically Based Research ◽  
Physical Chemical ◽  
Microbiological Agents ◽  
Promotion Process ◽  
Shed Light ◽  
Lnt Model

To protect the public’s health from exposure to physical, chemical, and microbiological agents, it is important that any policy be based on rigorous scientifically based research. The concept of “linear no-threshold” (LNT) has been implemented to provide guideline exposures to these agents. The practical limitation to testing this hypothesis is to provide sufficient samples for experimental or epidemiological studies. While there is no universally accepted understanding of most human diseases, there seems to be better understanding of cancer that might help resolve the “LNT” model. The public’s concern, after being exposed to radiation, is the potential of producing cancer. The most rigorous hypothesis of human carcinogenesis is the “multistage, multimechanism” chemical carcinogenesis model. The radiation carcinogenesis LNT model, rarely, if ever, built it into their support. It will be argued that this multistage, multimechanism model of carcinogenesis, involving the “initiation” of a single cell by a mutagen event, followed by chronic exposure to threshold levels of epigenetic agents or conditions that stimulate the clonal expansion of the “initiated” cell, can convert these benign cells to become invasive and metastatic. This “promotion” process can be interrupted, thereby preventing these initiated cells from transitioning to the “progression” process of invasion and metastasis.

scholarly journals Healthcare workers: occupational carcinogenic factors and cancer risk

2018 ◽  
Vol 5 (3) ◽  
pp. 25-39 ◽  
Author(s):  
L. G. Solenova ◽  
L. A. Nekrasova
Keyword(s):  
Breast Cancer ◽  
Cancer Risk ◽  
Birth Defects ◽  
Healthcare Workers ◽  
Night Shift ◽  
Epidemiological Studies ◽  
Antineoplastic Drugs ◽  
Actual Situation ◽  
Biological Factors ◽  
Physical Chemical

The number of healthcare workers is over two million in Russia. Many of them are exposed to hazardous physical, chemical and biological occupational factors acting along with psychological strain. The results of large epidemiological studies carried out in various countries revealed greater cancer risk in physicians and nurses: cancer of the breast, skin, brain and other sites. Higher cancer risk of lung, breast, uterine, ovary, brain is considered to be associated with ionizing radiation. The female healthcare workers who handle antineoplastic drugs showed a greater risk of birth defects in offspring, spontaneous abortions and breast cancer. In Russia, the growing number of accidents among healthcare workers following transmission of infection by carcinogenic biological factors such as HBV and HIV is observed. Higher risk of reproductive impairments, hyperplasia of the breast and uterine tissues, breast cancer are revealed in nurses working the night shift. In Russia, there is lack of epidemiological studies of cancer risk among healthcare workers, the number of medical personal exposed to occupational carcinogens is unknown. That all does not show the actual situation in our country and does not allow setting priorities in cancer prevention among medical workers.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Seeking to uncover biology's chemical roots

2019 ◽  
Vol 3 (5) ◽  
pp. 435-443 ◽  
Author(s):  
Addy Pross
Keyword(s):  
Environmental Changes ◽  
Biological Systems ◽  
Significant Development ◽  
The Road ◽  
Physical Chemical ◽  
Systems Chemistry ◽  
Biological World ◽  
Inanimate Matter ◽  
The Origin Of Life ◽  
Opening Up

Despite the considerable advances in molecular biology over the past several decades, the nature of the physical–chemical process by which inanimate matter become transformed into simplest life remains elusive. In this review, we describe recent advances in a relatively new area of chemistry, systems chemistry, which attempts to uncover the physical–chemical principles underlying that remarkable transformation. A significant development has been the discovery that within the space of chemical potentiality there exists a largely unexplored kinetic domain which could be termed dynamic kinetic chemistry. Our analysis suggests that all biological systems and associated sub-systems belong to this distinct domain, thereby facilitating the placement of biological systems within a coherent physical/chemical framework. That discovery offers new insights into the origin of life process, as well as opening the door toward the preparation of active materials able to self-heal, adapt to environmental changes, even communicate, mimicking what transpires routinely in the biological world. The road to simplest proto-life appears to be opening up.

Suicidal Behavior in German Adolescents

2015 ◽  
Vol 43 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Joana Straub ◽  
Ferdinand Keller ◽  
Nina Sproeber ◽  
Michael G. Koelch ◽  
Paul L. Plener
Keyword(s):  
Suicidal Behavior ◽  
Suicide Attempts ◽  
Depression Scale ◽  
Epidemiological Studies ◽  
Present Sample ◽  
Manic Symptoms ◽  
Symptoms Of Depression ◽  
Adolescent Sample ◽  
History Of ◽  
Sum Scores

Objective: Research in adults has identified an association between bipolar disorder and suicidal behavior. This relationship, however, has been insufficiently investigated in adolescents to date. Methods: 1,117 adolescents from 13 German schools (mean age = 14.83, SD = .63; 52.7% females) completed an extended German version of the Center for Epidemiological Studies Depression Scale (CES-D), which assesses depressive and manic symptoms during the last week, as well as the Self-Harm Behavior Questionnaire (SHBQ) for the assessment of lifetime suicidal behavior. Results: In the present sample 39.4% of the girls and 23.1% of the boys reported lifetime suicidal thoughts and 7.1% of the girls as well as 3.9% of the boys a lifetime history of suicide attempts. 18.7% of the adolescent sample revealed elevated symptoms of depression and 9% elevated levels of mania symptoms. Elevated sum scores of depression and mania were associated with a higher number of suicidal ideations and suicide attempts. A block-wise regression analysis revealed that sum scores of depression and mania predicted suicidal ideations best. Concerning suicide attempts, the best predictors were age as well as depression and mania sum scores. Conclusions: Suicidal behavior was reported more often when adolescents demonstrate symptoms of mania as well as symptoms of depression than when they demonstrate only depressive symptoms. The presence of bipolar symptoms in adolescents should alert clinicians to the heightened possibility of suicidal behavior.

Zur Anwendung der CES-D bei älteren Menschen: Dimensionsstruktur und Meßartefakte

Diagnostica ◽  
2000 ◽  
Vol 46 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Herbert Matschinger ◽  
Astrid Schork ◽  
Steffi G. Riedel-Heller ◽  
Matthias C. Angermeyer
Keyword(s):  
Mental State ◽  
Latent Class ◽  
Mini Mental State Examination ◽  
Depression Scale ◽  
Epidemiological Studies ◽  
Partial Credit ◽  
Examination Score ◽  
State Examination

Zusammenfassung. Beim Einsatz der Center for Epidemiological Studies Depression Scale (CES-D) stellt sich das Problem der Dimensionalität des Instruments, dessen Lösung durch die Konfundierung eines Teilkonstruktes (“Wohlbefinden”) mit Besonderheiten der Itemformulierung Schwierigkeiten bereitet, da Antwortartefakte zu erwarten sind. Dimensionsstruktur und Eignung der CES-D zur Erfassung der Depression bei älteren Menschen wurden an einer Stichprobe von 663 über 75-jährigen Teilnehmern der “Leipziger Langzeitstudie in der Altenbevölkerung” untersucht. Da sich die Annahme der Gültigkeit eines partial-credit-Rasch-Modells sowohl für die Gesamtstichprobe als auch für eine Teilpopulation als zu restriktiv erwies, wurde ein 3- bzw. 4-Klassen-latent-class-Modell für geordnete Kategorien berechnet und die 4-Klassen-Lösung als den Daten angemessen interpretiert: Drei Klassen zeigten sich im Sinne des Konstrukts “Depression” geordnet, eine Klasse enthielt jene Respondenten, deren Antwortmuster auf ein Antwortartefakt hinwiesen. In dieser Befragtenklasse wird der Depressionsgrad offensichtlich überschätzt. Zusammenhänge mit Alter und Mini-Mental-State-Examination-Score werden dargestellt. Nach unseren Ergebnissen muß die CES-D in einer Altenbevölkerung mit Vorsicht eingesetzt werden, der Summenscore sollte nicht verwendet werden.

Epidemiological Trends in Attempted Suicide in Adolescents and Young Adults Between 1996 and 2004

Crisis ◽  
2009 ◽  
Vol 30 (3) ◽  
pp. 115-119 ◽  
Author(s):  
Stephanie De Munck ◽  
Gwendolyn Portzky ◽  
Kees Van Heeringen
Keyword(s):  
Young Adults ◽  
Attempted Suicide ◽  
Suicide Attempts ◽  
Epidemiological Studies ◽  
Adolescents And Young Adults ◽  
University Hospital ◽  
International Studies ◽  
Suicide Attempters ◽  
Increased Risk ◽  
Epidemiological Trends

Background: Notwithstanding the epidemiological studies indicating an increased risk of attempted suicide among adolescents and young adults, there is a scarcity of international studies that examine long-term epidemiological trends in rates and characteristics of this vulnerable group. Aims: This article describes the results of a 9-year monitoring study of suicide attempts in adolescents and young adults referred to the Accident and Emergency Department of the Gent University Hospital (Belgium). Methods: Between January 1996 and December 2004, trends, sociodemographic, and methodrelated characteristics of suicide attempts were assessed by a psychiatrist on data sheets. Results: Attempted suicide rates declined from 1996 to 2001 and then rose until 2004, but did not exceed previous rates. During the 9 years of monitoring, there was a preponderance of female suicide attempters, except for 1997. Rates of attempts and of fatal suicide were negatively correlated. Significantly more males than females deliberately injured themselves. Younger attempters, especially females, significantly more often poisoned themselves with analgesics. In nearly one in five attempts, alcohol was used in combination with other methods, and alcohol intake was more commonly observed in older suicide attempters. Nearly half of the adolescents were identified as repeaters. Conclusions: The results of this study warrant further monitoring of trends and characteristics of young suicide attempters.

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