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Philip W. Wirtz 《Alcoholism, clinical and experimental research》2007,31(S3):57s-63s
Background: While causal modeling is generally well known to alcohol researchers, several causal structures (including suppression, mediated moderation, and moderated mediation) are often poorly understood and seldom employed when investigators seek to model the complex mechanisms of behavior change, despite their widespread applicability to the field.
Methods: This paper compares and contrasts five basic structures of causal modeling in the context of contemporary alcohol research and demonstrates how mechanisms of behavior change can be conceptualized and tested as parallel and serial sequences of these basic causal structures, forming causal chains.
Conclusion: Recent methodological developments, while representing an important advancement for the field, fail to adequately address the complexities of alcohol dependence phenomena. A differentiation between frequently combined forms of these causal structures is proposed that would better address the needs of the field. 相似文献
Methods: This paper compares and contrasts five basic structures of causal modeling in the context of contemporary alcohol research and demonstrates how mechanisms of behavior change can be conceptualized and tested as parallel and serial sequences of these basic causal structures, forming causal chains.
Conclusion: Recent methodological developments, while representing an important advancement for the field, fail to adequately address the complexities of alcohol dependence phenomena. A differentiation between frequently combined forms of these causal structures is proposed that would better address the needs of the field. 相似文献
4.
R. Fock H. Bergmann H. Bußmann G. Fell E.-J. Finke U. Koch M. Niedrig M. Peters D. Scholz A. Wirtz 《Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz》2001,44(10):969-980
The World Health Organization (WHO) and the majority of the influenza experts assume that an influenza pandemic might reemerge again at any time. Therefore WHO has called upon all member states to set up a national pandemic preparedness plan. For Germany such a plan is long overdue. In order to gain as much time as possible early identification of the pandemic virus is of highest priority. Furthermore progression of a pandemic is influenced by the time needed to develop a subtype specific vaccine as well as by the vaccines availability. However, in case of a pandemic a shortage of vaccines and prophylactic pharmaceuticals cannot be avoided. Therefore, decisions have to be made in order to establish priorities concerning the vaccination and the prophylactic and/or therapeutic antimicrobial treatment of selected sub-populations. There is also a need to lay down measures ensuring the distribution of vaccines and antiviral drugs, adequate health care and ambulance service, and the organization of dignified funerals of the deceased. It is also necessary to enter into an early agreement with vaccine manufacturers on a guaranteed supply of respective batches of vaccine doses. In addition procedures should be established to allow an increase in vaccine production in case of a pandemic. There is also a need for early agreements with the manufacturers of antiviral agents and for a decision concerning the establishment of a national stockpile to guarantee an adequate supply. Some measures must already be taken in the inter-pandemic period. Those are: enhancement of surveillance and research, development of new vaccines and new methods of vaccine production, licensing of new vaccines in case of a pandemic and establishment of a national influenza committee. Problems like the effectiveness of antiepidemic measures, such as immigration control and the closing of schools, must be solved in advance of a pandemic. 相似文献
5.
Zusammenfassung Hintergrund: Bei Patienten mit stumpfem Thoraxtrauma muss mit einer Contusio cordis gerechnet werden. Das Spektrum der Symptomatik variiert von einer leichten regionalen myokardialen Funktionsstörung bis hin zur Ruptur und zum plötzlichen Herztod. Fallbeschreibung: Ein 27-jähriger Patient wurde nach einem Fußtritt gegen die Brust bei Kammerflimmern reanimiert. Das EKG sowie das Enzymmuster entsprachen denen eines akuten Myokardinfarkts, echokardiographisch zeigte sich eine Hypokinesie apikal und anteroseptal bei mittelgradig reduzierter Pumpfuktion. Die 10 Tage nach dem Trauma durchgeführte Koronarangiographie und Lävokardiographie ergaben einen unauffälligen Befund. Schlussfolgerung: Als Ursache des primären Kammerflimmerns und der initialen elektro- und echokardiographischen Befunde muss aufgrund der Anamnese eine Contusio cordis diskutiert und in der Therapie berücksichtigt werden. Abstract Background: Patients with a blunt chest trauma often sustain myocardial contusion. The spectrum of symptoms varies from regional myocardial dysfunction to myocardial rupture of sudden cardiac death. Case Report: After a kick against his chest, a 27-year-old patient was resuscitated because of ventricular fibrillation. ECG and enzymatic pattern corresponded to an acute myocardial infarction, the echocardiogram revealed an apical and anteroseptal hypokinesia. 10 days after the acute event, coronary arteriography and ventriculography did not show any abnormalities. Conclusion: On the basis of the anamnesis, a myocardial contusion must be discussed as reason for the ventricular fibrillation and the pathologic findings in ECG and echocardiogram. This has to be considered in the therapy. 相似文献
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The prevalence of obesity in Germany has risen steadily in the last years; about 50% of the German population are overweight. There are various methods for determining obesity, such as BMI, the pattern of fat distribution, and the waist to hip ratio. Overweight is associated with chronic illnesses such as arterial hypertension, pulmoarterial hypertension, cardiomyopathy with left and right heart insufficiency, diabetes mellits type 2, all of which lead to an increased risk of morbidity and mortality. In addition, psychiatric comorbidity is known to occur. The care of obese patients provides an increasing medical and technical challenge in emergency medicine. We discuss the particular difficulties of examining obese patients in the emergency room (problems examining certain areas and in diagnosis due to excessive fatty tissue), at monitoring, in determining venous or intraosseous entrances, in airway management, respiration and artificial respiration, and during rescue and transport, and solutions offered. The outcome is, as a matter of course, worse in obese patients than in those with normal weight. 相似文献
7.
Relative carriage rates of nuclear dehydrogenating clostridia in two populations of different colorectal cancer risk
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Carriage of nuclear dehydrogenating clostridia has been associated with colon cancer and implicated in its aetiology. This study has compared the carriage of these organisms in a British population at high risk for the development of colon cancer with a low risk Nigerian population. Clostridia were found in all of the stools from both populations. Nuclear dehydrogenating clostridia were only found in the stools of the British subjects (32%). These results support the suggestion that the carriage rate of nuclear dehydrogenating clostridia in a population is related to the risk of colon cancer. 相似文献
8.
Development of hatching blastocysts from immature human oocytes following in-vitro maturation and fertilization using a co-culture system 总被引:8,自引:0,他引:8
Hwu YM; Lee RK; Chen CP; Su JT; Chen YW; Lin SP 《Human reproduction (Oxford, England)》1998,13(7):1916-1921
Recently, in-vitro maturation (IVM) of immature human oocytes recovered
from non-stimulated follicles has been applied in the treatment of
infertility. However, in previous reports, very few embryos cultured in
conventional medium have reached the expanded blastocyst stage following
in-vitro maturation and fertilization (IVM/IVF). The objective of this
study was to investigate whether the developmental competence of human
embryos following IVM/IVF could be enhanced by the use of a human ampullary
cell co-culture system. Immature human oocytes were aspirated from small
follicles at Caesarean section and then cultured in medium containing human
menopausal gonadotrophin for 36 to 48 h, followed by insemination. Zygotes
were randomly cultured either in conventional culture medium alone or in
the co-culture system. Of 48 embryos cultured in conventional medium alone,
all arrested at the 2-16- cell stage on day 3 after insemination. Of 46
embryos cultured in the co-culture system, 26 embryos (56.5%) arrested at
the 2-16-cell stage. Six embryos (13%) developed to the morula stage.
Fourteen embryos (30.4%) developed to expanded blastocysts and two
blastocysts were hatching on day 7 after insemination. We conclude that
co-culture significantly enhances the development of blastocysts in embryos
resulting from IVM/IVF.
相似文献
9.
Detection of chromosomes and estimation of aneuploidy in human spermatozoa using fluorescence in-situ hybridization 总被引:11,自引:0,他引:11
The development and application of fluorescence in-situ hybridization
(FISH) has opened the way for comprehensive studies on numerical chromosome
abnormalities in human spermatozoa. FISH can be rapidly applied to large
numbers of spermatozoa and thus overcomes the major limitation of
karyotyping spermatozoa after penetration of zona-free hamster oocytes. The
simultaneous hybridization of two or more chromosome-specific probes to
spermatozoa and subsequent detection of the bound probes using different
fluorescent detection systems enables two or more chromosomes to be
localized simultaneously in the same spermatozoon and provides a technique
for undertaking reasonable estimates of aneuploidy. The most commonly used
probes are those which bind to the centromeric region of specific
chromosomes. Most studies to date have concentrated on estimating
aneuploidy in spermatozoa from normospermic men, although reports are
beginning to appear on aneuploidy in spermatozoa from subfertile and
infertile men. Multi- probe FISH studies have generally reported disomy
(hyperhaploidy) estimates of 0.05-0.2% per chromosome. There is preliminary
evidence that some chromosomes such as X, Y and 21 are predisposed towards
higher rates of non-disjunction during spermatogenesis. There are also
suggestions of inter-donor variability in aneuploidy frequencies for
specific chromosomes, although this requires confirmation in larger
studies. While FISH is clearly a powerful technique that has many
applications in reproductive medicine, it must also be realized that it
does have limitations and the technology itself is still evolving and has
yet to be fully validated on spermatozoa.
相似文献
10.