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The "air leak" test around the endotracheal tube, as a predictor of postextubation stridor, is age dependent in children.

OBJECTIVES: The airleak test is measured with a manometer as the pressure necessary to generate an audible airleak around the endotracheal tube. Our objectives were to determine whether the airleak test predicts postextubation stridor in children and if age affects its sensitivity and specificity. DESIGN: A retrospective study. SETTING: Pediatric intensive care unit. PATIENTS: We studied all intubated patients admitted to our pediatric intensive care unit between July 1998 and December 1999. Patients were excluded if they had acute viral croup, tracheal surgery, hypotonic airway, or vocal cord paralysis or if they died before extubation. INTERVENTIONS: Medical records were reviewed for patient demographics, presence of an airleak on the day of extubation, airleak values, presence of postextubation stridor, and extubation failure secondary to upper airway obstruction. MEASUREMENTS AND MAIN RESULTS: One hundred and five patients met our inclusion criteria and had an airleak test at the time of extubation. In children <7 yrs of age, the incidence of postextubation stridor was similar in patients with or without an airleak at >20 mm Hg (50% vs. 67.7%; >.05) with a sensitivity of 65.6% (95% confidence interval, 46.9-80.8). In children >or=7 yrs of age, the incidence of postextubation stridor was greater in patients with an airleak at >20 mm Hg (55.5% vs. 5.8%; p=.01) with a sensitivity of 83.3% (95% confidence interval, 36.8-99) in predicting postextubation stridor. CONCLUSIONS: Our study suggests that the airleak test has a low sensitivity when used as a screening test to predict postextubation stridor in young children (<7 yrs old), whereas in older children (>or=7 yrs old) the airleak test may predict postextubation stridor.

Adolescent↗

In vitro primary sensitization of hapten-specific T cells by cultured human epidermal Langerhans cells--a screening predictive assay for contact sensitizers.

BACKGROUND: The need to develop predictive tests which could identify potential allergens has been recognized for many years. There is as yet no accepted in vitro method for the assessment of contact sensitizers. OBJECTIVE: We have tested the ability of a range of contact allergens to induce in vitro primary sensitization of autologous T cells. METHOD: T-cell proliferation induced by haptens using 2-day cultured human Langerhans cells as antigen-presenting cell was assessed by 3H thymidine incorporation. Antigen specific stimulation was calculated as stimulation indexes. RESULTS: Strong allergens induced in vitro a primary T-cell response in all (trinitrophenyl, TNP: 13/13) or in the majority (fluorescein isothiocyanate, FITC: 7/10) of experiments. An irritant, sodium dodecyl sulfate (SDS), failed to generate a significant T-cell proliferation in any of the experiments (0/10). We obtained a significant lymphoproliferative response to weak sensitizers only in a limited number of experiments: (coumarin: 1/12, citronellal: 0/10, hydroxycitronellal: 2/8). p-Phenylenediamine (PPDA), a prohapten and highly sensitizing chemical in vivo, generated primary sensitization in vitro in only one of six experiments, while Bandrowski's base (BB), a metabolization product of PPDA induced a significant T-cell response in all six experiments. CONCLUSION: The present in vitro model allows discrimination between two groups of substances: strong contact sensitizers (TNP, FITC, BB) on the one hand and weak sensitizers (coumarin, citronellal and hydroxycitronellal) and irritants (SDS) on the other hand. It could be used as a screening in vitro assay to eliminate strong contact allergens before further predictive animal tests have to be performed.

Coumarins↗

Testing specificity and guidance hypotheses by manipulating relative frequency of KR scheduling in motor skill acquisition.

This investigation tested predictions of specificity and guidance hypotheses by manipulating relative frequency of knowledge of results scheduling using a shuffleboard task. Participants were assigned to either a 100%-KR, three 50%-KR conditions (Constant, Fade, Reverse), or 00%-KR condition. Based on predictions of the specificity hypothesis, it was expected the 00%-KR condition would perform the best on a no-KR retention test. It was also expected the 100%-KR condition would perform poorly on a no-KR retention test based on predictions of the guidance hypothesis. Analysis for 55 men's and 55 women's retention did not support predictions of the specificity hypothesis and provided partial support for the guidance hypothesis.

Adult↗

Dynamic changes in hypermnesia across early and late tests: a relational/item-specific account.

Two experiments tested predictions derived from R. R. Hunt and M. A. McDaniel's (1993) relational/item-specific account of hypermnesia. According to this framework, participants encoding relational information should show greater hypermnesia on early test trials than on later test trials. In contrast, participants encoding item-specific information should show greater hypermnesia on later test trials than on early test trials. These predictions were not anticipated by other accounts but were confirmed by the results. Further, the patterns of reminiscence and intertest forgetting supported the theoretical underpinnings of these predictions. A 3rd experiment examined some factors by which item-specific encoding might enhance reminiscence (and thus hypermnesia) on later test trials. These results suggested that a richer set of encoded attributes rather than a fluctuating retrieval plan supported the beneficial effects of item-specific encoding on reminiscence.

Female↗

Reference values for respiratory function tests in males: prediction formulas with tobacco smoking parameters.

Prediction equations for respiratory function tests were obtained by multiple regression of data from 263 healthy males. The material was evenly distributed in the ages 20-70 years, about one third each of non-smokers, smokers and ex-smokers. Measurements were done of lung volumes (with body plethysmograph), airways resistance, ventilatory capacity including flow-volume registration, gas distribution and closing volume, transfer factor and static elastic recoil pressures of the lung with calculation of static compliance. The parameters age, height, weight, years of tobacco smoking and grams of tobacco smoked each day showed significant correlation with the outcome of the test in most of the respiratory function tests. Therefore a set of basic regression equations including these parameters were calculated. In addition an 'extended' set of equations was calculated for prediction of some tests with inclusion of nonlinear terms and the parameter 'years of abstinence from smoking.' The reduction in variance which followed inclusion of tested parameters was moderate (20-69%). There were significant differences between results of the present study and several previously published regression formulas.

Adolescent↗

Serial salivary estriol to detect an increased risk of preterm birth.

OBJECTIVE: To evaluate serial measurements of salivary estriol (E3) to detect increased risk of spontaneous preterm labor and preterm birth. METHODS: A masked, prospective, multicenter trial of 956 women with singleton pregnancies was completed at eight United States medical centers. Saliva was collected weekly, beginning at the 22nd week of gestation until birth, and tested for unconjugated E3 by enzyme-linked immunosorbent assay. Women were separated into high-risk and low-risk groups using the Creasy scoring system. RESULTS: A single, positive (at or above 2.1 ng/mL) salivary E3 test predicted an increased risk of spontaneous preterm labor and delivery in the total population (relative risk [RR] 4.0, P <.005), in the low-risk population (RR 4.0, P < or =.05), and in the high-risk population (RR 3.4, P =.05). Two consecutive positive tests significantly increased the RR in all study groups, with a dramatic improvement in test specificity and positive predictive value but only a modest decrease in sensitivity. In women who presented with symptomatic preterm labor, salivary E3 identified 61% of those who delivered within 2 weeks, using a threshold of 1.4 ng/mL. CONCLUSION: Elevated salivary E3 is associated with increased risk of preterm birth in asymptomatic women and symptomatic women who present for evaluation of preterm labor.

Adult↗

Intrapartum umbilical artery Doppler velocimetry as a predictor of adverse perinatal outcome: a systematic review.

OBJECTIVE: To evaluate the diagnostic prediction of intrapartum umbilical artery Doppler velocimetry for adverse perinatal outcomes using systematic quantitative overview of the available literature. DESIGN: Online searching of MEDLINE database (January 1966-September 1997), scanning of bibliography of known primary and review articles, review of recent journal issues and that from personal files. Study selection, assessment of study quality and data extraction were all performed in duplicate under masked conditions. PARTICIPANTS: 2700 women (unselected, low, high, and combined low and high obstetric risk populations) included in eight studies selected for meta-analyses. MAIN OUTCOME MEASURES: Likelihood ratios (LRs) for positive and negative test results were generated for the following outcome measures: Apgar scores < 7 at 1 and 5 minute following delivery, small for gestational age fetus; intrapartum fetal heart rate abnormality, umbilical arterial acidosis at delivery; and caesarean section for fetal distress. RESULTS: For Apgar score < 7 at 1 minute following delivery, the pooled LR was 2.5 (95% CI 1.7-3.7) for a positive test and 1.0 (95% CI 0.9-1.1) for a negative test result. A positive test predicted an Apgar score < 7 at 5 minute following delivery with a pooled LR of 1.3 (95% CI 0.4-4.1) while a negative test had a pooled LR of 1.0 (95% CI 0.8-1.2). For the prediction of a small for gestational age fetus, the pooled LR was 3.4 (95% CI 2.3-5.1) for a positive test and 0.9 (95% CI 0.8-1.0) for a negative test. The prediction for fetal heart rate abnormality during labour was similarly disappointing: the pooled LR for a positive test result was 1.4 (95% CI 0.9-1.2) whereas a negative test result generated a pooled LR of 0.9 (95% CI 0.9-1.0). With umbilical acidosis at delivery, the pooled LR was 1.6 (95% CI 1.1-2.5) for a positive test and 1.1 (95% CI 1.0-1.2) for a negative test. The LRs for the prediction of caesarean section for fetal distress were 4.1 (95% CI 2.7-6.2) for a positive test result and 0.9 (95% CI 0.8-1.0) for a negative test result. CONCLUSION: Intrapartum umbilical artery Doppler velocimetry is a poor predictor of adverse perinatal outcomes.

Blood Flow Velocity↗

Further evidence for latent learning in hippocampal-lesioned rats.

Rats with substantial dorsolateral lesions to the hippocampal formation showed significant latent learning of a complex spatial maze. Their overall maze performance, however, was characteristically impaired. Behavior during the pre-exposure phase of the experiment was useful in predicting test maze behavior. Three measures in particular had predictive value: entrances into the maze alley leading to the final choice point, behavior at that choice point, and goal box entries.

Animals↗

Postural asymmetry and directionality of rotation in rats.

The hypothesis [12] that the direction of postural asymmetry can predict rotational side preferences caused by amphetamine, was tested. Postural asymmetry of male and female Wistar rats was assessed using four tests: (a) tail suspension, (b) tail holding, (c) tail pinch, and (d) walking on a narrow path. The tests were conducted prior to and after (+)-amphetamine (1 mg/kg, IP) administration. Rotational directionality was assessed in a rotometer. None of the tests predicted the direction of circling. The findings suggest that there is a multitude of systems contributing to asymmetric posture.

Animals↗

Apomorphine-induced penile tumescence in impotent patients--preliminary findings.

Apomorphine (Apo), a short acting dopamine (DA) receptor agonist induces penile erections in normal subjects. The erectile response to one or more doses of Apo HCl (0.25, 0.5, 0.75, 1.0 mg sc) or placebo was investigated in eight impotent subjects and penile tumescence monitored using a mercury strain gauge and strip chart recording. Four patients showed a full erection with Apo and one a partial response. Distressing side effects (nausea, sweating) were associated with non-response or partial response. Three responders to Apo were treated with low doses of the long acting DA receptor agonist, bromocriptine (2.5-3.75 mg/d po); all three showed complete recovery of erectile function within two weeks. A subgroup of impotent patients may have impaired central DA function. Testing with Apo may provide a diagnostic and predictive test to identify such patients who may respond to treatment with low doses of bromocriptine or other DA receptor agonist.

Adult↗

Sedentary daily expenditure: a base for estimating individual energy requirements.

As a base for estimating individual energy requirements, we propose using the energy expenditure of a sedentary day with regular meals and sleep at night. Ninety-five 24-h measurements of sedentary daily expenditure (SDE) by direct calorimetry on 37 men and women were analyzed, showing that fat-free mass combined with body mass index correlated highly with SDE (r2 = 0.92) with an SE of 5%. Weight and fat mass were better predictors for women and excellent predictors for men. We found that weight and height accurately predicted fat mass if suitable exponents were used in the expression wt/htx. Testing predictive equations with our own and other sets of data showed good agreement between estimated and observed SDEs. As a base for estimating individual energy requirements. SDE is more precise than basal metabolic rate and it can be predicted with useful accuracy from simple measures of weight and height.

Adipose Tissue↗

Mechanism of e47-Pip interaction on DNA resulting in transcriptional synergy and activation of immunoglobulin germ line sterile transcripts.

E47 and Pip are proteins crucial for proper B-cell development. E47 and Pip cooperatively bind to adjacent sites in the immunoglobulin kappa chain 3' enhancer and generate a potent transcriptional synergy. We generated protein-DNA computer models to visualize E47 and Pip bound to DNA. These models predict precise interactions between the two proteins. We tested predictions deduced from these models by mutagenesis studies and found evidence for novel direct interactions between the E47 helix-loop-helix domain (Arg 357 or Asp 358) and the Pip N terminus (Leu 24). We also found that precise spatial alignment of the binding sites was necessary for transcriptional synergy and cooperative DNA binding. A Pip dominant negative mutant that cannot synergize with E47 inhibited enhancer activity in plasmacytoma cells and could not activate transcription in pre-B cells. Using electrophoretic mobility shift assays, we found that Pip can bind to the heavy-chain intron enhancer region. In addition, we found that in fibroblasts Pip greatly increased E47 induction of germ line I micro transcripts associated with somatic rearrangement and isotype class switching. However, a Pip dominant negative mutant inhibited germ line I micro transcripts. The importance of these results for late B-cell functions is discussed.

3T3 Cells↗

[Transplantation of malignant ovarian tumors into athymic nu/nu mice].

Routinely performed xenotransplantations of 216 different malignant ovarian tumors on thymusaplastic nu/nu mice (NMRI) are reported. Take-off rate defined as proof of histologically vital cells and outer measurable growth was 76 percent. However, a second or further animal passages were possible only in almost 40 percent. About 20 percent of malignant ovarian tumors could be serilly xenotransplanted. The influence of grade of histological differentiation, of origin of tumor tissue (primary, metastasis), and of tissue's steroid receptor content on the growth of ovarian xenotransplants could be demonstrated. The human origin of the xenotransplants - even in later animal passages - could be determined in all cases by isoenzyme analysis. However, the growing rate of mitoses indicates a change of cell proliferation of the xenotransplants. Because of that the nude mice model seems not be appropriate as an individual 'predictive test', but it is excellent as a preclinical prediction for the effect of newly developed cytostatics or the relevance of different therapeutical approaches.

Animals↗

Emerging ethical issues in pharmacogenomics: from research to clinical practice.

Pharmacogenomics holds much promise for the application of genetic information to the improvement of clinical care. Ethical issues for pharmacogenomics arise at the intersection of the spheres of drug development and genetic testing. Clinical drug trial designs which use subject selection based on genotype must consider the features of scientific validity, social value and risk-benefit ratio, and later, the impact of this strategy on post-market studies and clinical use of drugs. Although the testing context for pharmacogenomic tests is different from other genetic tests, decisions to use any new clinical tests in medical practice will require evaluation of not only the benefit linked to improved drug use but also the risks arising in part from the scale of testing, predictive value and collateral potential of the genetic test. Integration of pharmacogenomic information into clinical practice will require clinical trials to assess their clinical usefulness, including the impact of tests on therapeutic outcomes. Trials will also be needed to demonstrate the effectiveness of education, informed consent and counseling.

Animals↗

Can islet cell antibodies predict IDDM in the general population?

OBJECTIVE: To evaluate the likely prognostic significance of ICAs in children with no family history of IDDM. RESEARCH DESIGN AND METHODS: We examined the prevalence of ICAs in 2925 English schoolchildren aged 9-13 yr and in 274 age-matched siblings of children with diabetes from the same region, and we compared the estimated risk of progression to diabetes within 10 yr in the two groups. RESULTS: ICAs were present at levels > or = 4 JDF U in 2.8% of schoolchildren and 6.6% of siblings and at > or = 20 JDF U in 0.8% of schoolchildren and 2.2% of siblings. Although ICAs are only 2-3 times more prevalent in siblings than schoolchildren, the estimated cumulative risk that siblings will progress to diabetes by age 21 is 13 times greater (2.8 vs. 0.21%). CONCLUSIONS: ICAs are unexpectedly prevalent in English schoolchildren, but only a small minority, with this evidence of immune activation directed against islet cells, will progress to diabetes. Although ICAs alone have limited predictive value in the general population, combining two or more predictive tests in series could achieve a level of prediction equivalent to that now obtained in first-degree relatives.

Adolescent↗

Do couples make fertility plans one birth at a time?

Criteria are specified for distinguishing one-decision from sequential-decision models of fertility. Sequential decisions are not demonstrated by parity-specific differences in fertility determinants. Sequential models must demonstrate the importance of unanticipated intervening events in changing fertility plans or fertility experience. They must demonstrate that the intervening events are not caused by the fertility. Two empirical tests are designed to determine which model best fits the data. One test predicts fertility plans, the other fertility events. Both tests provide some support for sequential models.

Birth Intervals↗

Anticaries efficacy of an improved stannous fluoride toothpaste.

A series of laboratory and animal studies were conducted to confirm the anticaries potential of a new, stabilized stannous fluoride (SnF2) dentifrice relative to clinically proven SnF2 controls. Included in this series of assessments were fluoride uptake into demineralized human enamel, remineralization/inhibition of demineralization for both human enamel and roots, and animal caries studies. Each of these studies demonstrate the new, stabilized SnF2 dentifrice (Crest Gum Care toothpaste) is effective at inhibiting and reversing the caries process. These data confirm that this new dentifrice, formulated with a combination of SnF2, and hydrated silica, is predicted to be highly effective against caries. These tests predict that this new stabilized SnF2 dentifrice (Crest Gum Care toothpaste) provides a level of anticaries activity that is equivalent to Crest Regular toothpaste, a sodium fluoride (NaF)/silica product. The data suggest that this new formulation provides enhanced anticaries efficacy relative to previous, unstabilized SnF2 formulations as a result of improved fluoride bioavailability.

Analysis of Variance↗

Patterns of mold sensitivity in the subtropical Gulf Coast.

OBJECTIVES: We sought to determine the patterns of mold- and nonmold positive skin tests in a subtropical Gulf Coast climate and to determine whether any particular positive skin tests predict "allergic versus nonallergic" status as shown on the full panel of skin testing. STUDY DESIGN AND SETTING: We conducted a retrospective evaluation of serial endpoint allergy skin test results in 75 consecutive patients from a tertiary referral medical center. RESULTS: Of the 67 evaluable patients, 58 (86.6%) had a positive skin test to at least 1 antigen. The most common positive skin tests were in response to cockroach, Dermatophygoides farinae, Bermuda grass, false ragweed, mesquite, Stemphylium, Curvularia, short ragweed, and Timothy grass. There were no identifiable groups of antigens that tended to occur together. Screening with a panel of 6 antigens (cockroach, dust mite, cat, rough marsh elder, Timothy grass, and Stemphylium) would have correctly predicted whether the patient would react to any or none of the full panel of antigens. CONCLUSION: Cockroach, dust mite, and a grass were the most common positive skin tests among our patients, with many patients also having positive skin tests to molds. Although there is evidence that cross-reactivity exists among different mold species, we were unable to identify any clusters of mold reacting together in individual patients. In our patient population, a 6-allergen screening panel (cockroach, dust mite, cat, rough marsh elder, Timothy grass, and Stemphylium) would have accurately distinguished "allergic" from "nonallergic" patients, as demonstrated on the full panel of skin testing. SIGNIFICANCE: A small (6-antigen) screening panel accurately predicted "allergic" versus "nonallergic" as shown by our full panel of skin testing. This is useful clinically when an "allergic versus nonallergic" etiology of sinonasal symptoms affects treatment choices.

Adult↗