Integrating four theories of adolescent smoking

The ability of the Theory of Planned Behavior, Social Learning Theory, Social Attachment Theory, and Problem Behavior Theory to predict smoking at Grade 10 was tested against an integrated model incorporating predictors from all the theories. The integrated model also tested whether constructs from each theory contribute distinct variance to the prediction of smoking. Predictors measured at Grade 7 (in 1985) were used to model smoking 3 years later (in 1988) among 4186 youth, using logistic regression. Constructs emphasized by each theory were important, independent predictors of later smoking. The integrated model was superior to all of the theory-based models. A few predictors varied for current vs. frequent smoking outcomes. Results emphasize the need for a multifaceted approach to understanding and preventing adolescent smoking.     

In vivo measurements of changes in respiratory mechanics with age in mice deficient in surfactant protein D

Mice deficient in surfactant protein D [SP-D (-/-)] develop progressive emphysema with age, associated with loss of parenchymal tissue, subpleural fibrosis, and accumulation of abnormal elastin fibers. We measured the changes in lung function, partitioned into components for the airways and lung parenchyma, occurring with age in SP-D (-/-) mice at three ages (n = 8 per group) (5, 8, and 13 wk). Impedance spectra between 0.25 and 19.625 Hz were calculated and a model, consisting of an airway compartment [airway resistance (Raw) and inertance (Iaw)] and a constant-phase tissue compartment [coefficients of tissue damping (G) and elastance (H)], was fitted to the data. Hysteresivity was calculated as G/H. Adult values of Raw, G, and H are reached by 8 wk of age in wild-type controls. Raw and H were lower at all ages in SP-D (-/-) compared with the wild-type controls (p = 0.006 and 0.029, respectively), and a similar trend was seen in G (p = 0.060). The patterns of change in respiratory mechanics were similar in both SP-D (+/+) and (-/-) groups. There were no changes in hysteresivity with age and no differences between wild-type and SP-D (-/-) mice. These data demonstrate that the changes in lung structure in SP-D (-/-) mice are reflected in the mechanical properties of both airway and lung parenchyma measured in vivo.     

Long-term survival of aortic atresia following biventricular corrective surgery

A female born with aortic atresia, large ventricular septal defect, normal mitral valve, and left ventricle is well at 21 years of age following biventricular repair. She had palliative surgery at 15 days and closure of ventricular septal defect with placement of a valved conduit from the left ventricular apex to descending aorta at 15 months. Conduit was replaced at 34 months and at 10 and 21.5 years of age.     

Evaluating systematic reviews and meta-analyses

Systematic review and meta-analysis procedures make use of explicit methods to methodically search and critically appraise and synthesize the medical care research literature. The methods involve refining a clinical question, designing a search procedure to find eligible studies, and determining the validity of the eligible studies. Independent data extraction by two or more reviewers is preferred. Agreement between the reviewers with respect to relevance and validity should be measured. Meta-analysis procedures estimate an overall average effect from the individual study effects and determine whether these effects appear to measure the same relationship (that is, the studies are not heterogeneous). In the inverse variance method, which is most frequently applied, the overall effect is a weighted average of the individual study effects, where each weight is the inverse of the study variance. To evaluate a systematic review, first determine whether it addresses a question that is relevant to the patients, treatments, and outcomes that are usual in your clinical practice. Then assess the validity of the systematic review, which is reflected by quality of the individual studies, the rigor with which the systematic methods were applied, and the extent of heterogeneity. If the results of the systematic review are valid, then is the effect important enough to make a difference in your clinical practice? Applying the results to an individual patient involves the absolute treatment effect or the number needed to treat, and an awareness of the patient's specific level of risk and personal preferences.     

Evidence-based medicine for treatment: an in vitro fertilization trial

Evidence-based evaluation of treatment is a pivotal component of an effective and satisfying clinical practice. When the best evidence has been identified, it can be efficiently assessed on three levels: Are the methods valid? Is the effect sufficiently large to be meaningful to patients? Are the patients, intervention(s), and outcomes studied applicable to our own patients? These criteria were applied to a multicenter trial that evaluated whether intracytoplasmic sperm injection (ICSI) was superior to in vitro fertilization (IVF) among infertile couples with no known male factor who were on a waiting list for IVF. The study was a well-designed randomized controlled trial that effectively concealed the randomization list and took reasonable steps to exclude bias. The results seemed important because the number needed to treat (13) was relatively low and significant, but the primary outcome (implantation rate) was not clinically meaningful. The trial results would have been relevant to most infertile couples with no known male factor if it had been powered to evaluate a difference in a more relevant clinical outcome, such as live birth. Thus, it has not been shown definitively that ICSI is inferior to IVF among couples with no known male factor, and clinical demand for ICSI may continue to rise.     

Nonoperative trauma management: has the pendulum swung too far? The distinguished Dr. William Matory lecture.

Over the last decade, the role of nonoperative management has revolutionized the specialty of trauma. However, this management paradigm has generated substantial controversy in several areas, including penetrating neck and abdominal trauma. Evidence-based analysis will be the ultimate guideline to determine what is optimal management. To prevent the pendulum from swinging too far, there should always exist a high index of suspicion to possible complications associated with the nonoperative approach. Also, the specific choice of management should be institution- and resource dependent.     

Detection of Francisella tularensis within infected mouse tissues by using a hand-held PCR thermocycler

The diagnosis of human cases of tularemia often relies upon the demonstration of an antibody response to Francisella tularensis or the direct culturing of the bacteria from the patient. Antibody response is not detectable until 2 weeks or more after infection, and culturing requires special media and suspicion of tularemia. In addition, handling live Francisella poses a risk to laboratory personnel due to the highly infectious nature of this pathogen. In an effort to develop a rapid diagnostic assay for tularemia, we investigated the use of TaqMan 5' hydrolysis fluorogenic PCR to detect the organism in tissues of infected mice. Mice were infected to produce respiratory tularemia. The fopA and tul4 genes of F. tularensis were amplified from infected spleen, lung, liver, and kidney tissues sampled over a 5-day period. The samples were analyzed using the laboratory-based Applied Biosystems International 7900 and the Smiths Detection-Edgewood BioSeeq, a hand-held portable fluorescence thermocycler designed for use in the field. A comparison of culturing and PCR for detection of bacteria in infected tissues shows that culturing was more sensitive than PCR. However, the results for culture take 72 h, whereas PCR results were available within 4 h. PCR was able to detect infection in all the tissues tested. Lung tissue showed the earliest response at 2 days when tested with the ABI 7900 and in 3 days when tested with the BioSeeq. The results were in agreement between the ABI 7900 and the BioSeeq when presented with the same sample. Template preparation may account for the loss of sensitivity compared to culturing techniques. The hand-held BioSeeq thermocycler shows promise as an expedient means of forward diagnosis of infection in the field.     

Personality factors and emotional responses to pregnancy among IVF couples in early pregnancy: a comparative study

BACKGROUND: Little is known as to whether negative experiences associated with infertility and IVF treatment persist after successful treatment. The aim of the study was to compare couples who have conceived after IVF and couples who have conceived naturally regarding personality factors and emotional responses to pregnancy. METHODS: Fifty-seven women pregnant after IVF and 55 male partners and 43 women who had conceived naturally and 39 male partners were recruited from university IVF clinics and antenatal clinics in Stockholm. The subjects were interviewed about their socio-demographic background. They completed scales of personality traits, anxiety, emotional responses to pregnancy, marital adjustment and reactions to recalled infertility while in pregnancy week 13 (range 11-17). RESULTS: The results showed that the IVF women had more muscular tension and were more anxious about loosing the pregnancy than the control women. The IVF women with high infertility distress were more anxious about loosing the pregnancy and less ambivalent than the women with lower distress. The IVF men had more somatic anxiety, indirect aggression, guilt, and were more detached and more anxious about loosing the pregnancy and less ambivalent than the control men. The IVF men with high infertility distress were more anxious about the baby not being normal than the men with lower infertility distress. CONCLUSIONS: The women and men who had conceived after IVF differed on a number of personality dimensions and emotional responses to the pregnancy from that of the women and the men who had conceived naturally. The results suggest that IVF couples may need additional emotional support in early pregnancy.     

Uterine contraction frequency before and after successful tocolytic therapy for preterm uterine contractions

OBJECTIVE: To examine the association between prelabor uterine contraction frequency (UCF) and the success of tocolytic therapy for preterm labor (PTL). STUDY DESIGN: Eleven centers conducted a prospective, observational study of UCF recorded between 22(0/7) and 36(6/7) weeks' gestational age or until delivery > or = 2 times/d on > or = 2 d/wk in women with singleton pregnancies with and without risk factors for preterm birth. Uterine contraction data obtained from patients diagnosed with PTL allowed comparison of mean UCF both before and after an acute episode of PTL treated with either intravenous, subcutaneous or oral tocolysis. The signed rank test was used to analyze differences in UCF before and after tocolytic therapy and between women who were or were not successfully treated with a labor-inhibiting agent. RESULTS: Of 454 enrolled women, 128 were diagnosed with PTL, and 74 were successfully treated with a labor-inhibiting agent. The mean UCF preceding PTL was not different between those women successfully treated and those who delivered as a consequence of the PTL episode. There was no difference (P = .653) in mean UCF between the week before PTL (UCF 0.60 +/- 0.8, median 0.30) and the first week of monitoring after successful tocolysis (UCF 0.82 +/- 1.4, median 0.27). CONCLUSION: The mean UCF immediately preceding PTL does not predict tocolytic success or failure.