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Biomedical subjects

N Schmitt

Publications and source records attributed to N Schmitt.

At least 19 recordsLinked to original sources
PubMed2004

Reduction in late postoperative pain after iliac crest bonegraft harvesting for cervical fusion: a controlled double-blinded study of 100 patients.

BACKGROUND: A randomized prospective double-blinded study was conducted in 100 patients suffering from mono- or bisegmental cervical retrospondylosis or disc herniation. METHOD: In group I, 50 patients were treated by injection of 10 ml Ropivacaine 7,5% at the iliac crest bonegraft donor site. Local anaesthetic (LA) was injected through the wound drainage after closure of the muscle fascia, the suction drainage was opened after closure of the skin. Group II was treated with 0,9% saline. Operator and patient were blinded to the injected substance. Daily controls of pain intensity were made with the 10 cm visual analog scale from 0 (no pain) to 10 (severe pain) for 5 days. All patients were questioned regarding pain character and movement provoking pain. Additional pain medication was standardized. FINDINGS: Statistical analysis of mean pain intensity over the whole hospital stay showed a significant difference in pain intensity between the two groups (p = 0,017, Chi-Square test). The comparison between pain intensity with LA and without LA showed a gradual increase in statistical significance from day 1 to day 5 (day 1: p = 0,54, not significant; day 2: p = 0,026; day 3: p = 0,008; day 4: p = 0,004; day 5: p = 0,002). INTERPRETATION: This data shows that intra-operative blockage of peripheral nociceptive structures results in decreased pain at later time points. We conclude that wound infiltration with 7,5% Ropivacaine after bonegraft removal at the iliac crest is effective in reducing postoperative pain.

Adolescent↗
PubMed2002

Linearity of canal-otolith interaction during eccentric rotation in humans.

During natural behavior, the head may simultaneously undergo rotation, transduced by the semicircular canals, and translation, transduced by the otolith organs. It has been demonstrated in monkey that the vestibulo-ocular reflexes (VORs) elicited by both endorgans (i.e., the angular and linear VORs, or AVOR and LVOR) sum linearly during combined rotation and translation, but this finding has proven more elusive in humans. To investigate the combined AVOR/LVOR response, six human subjects underwent yaw eccentric rotation at 3 Hz in darkness while displaced from the axis of rotation. Responses to on-center yaw rotation (AVOR alone) and interaural translation (LVOR alone) were also recorded. During eccentric rotation with the subject facing away from the axis of rotation (i.e., nose out), in which a yaw to the right occurs simultaneously with a translation to the right (i.e., translation in phase with rotation), the AVOR and LVOR acted synergistically. Responses were always out of phase with rotation, and became larger in magnitude as vergence increased. For nose-in eccentric rotation, during which translation is out of phase with rotation, the LVOR acted antagonistically to the AVOR. During near viewing, the LVOR often dominated the overall response when eccentricity was sufficiently large, producing eye movements that were in phase with the rotational stimuli. As vergence decreased, the LVOR influence diminished, eventually resulting in responses that were out of phase with rotation at lowest vergence. When the response to pure yaw rotation was vectorially removed from the responses to eccentric rotation, the results proved statistically indistinguishable from the LVOR recorded during interaural translation, suggesting that the ocular response to combined angular and linear motion reflects the linear combination of the AVOR and LVOR.

Adult↗
PubMed2002

Calcium solubility of dental enamel following sub-ablative Er:YAG and Er:YSGG laser irradiation in vitro.

BACKGROUND AND OBJECTIVE: The objective of the present study was to investigate the effect of sub-ablative Er:YAG (lambda = 2.94 microm) and Er:YSGG (lambda = 2.79 microm) laser radiation on the acid solubility of dental enamel. The influence of fluoride application prior to laser irradiation was additionally evaluated. STUDY DESIGN/MATERIALS AND METHODS: To this end, 294 enamel specimens were prepared from bovine teeth and divided into 14 groups of 21 specimens each. The enamel samples were irradiated in their groups with the Er:YAG and the Er:YSGG laser, using energy densities of 4, 6, and 8 J/cm(2) in each case. Irradiation was additionally repeated in the same way on specimens, which had previously been immersed in 1% sodium fluoride solution for 15 minutes. One group was left untreated and served as a control group. A further group was not irradiated, but only immersed in the 1% fluoride solution for 15 minutes. The enamel specimens were demineralised for 24 hours in an acetate buffer solution. The calcium content in the demineralisation solution was subsequently determined with the aid of atomic absorption spectrometry. RESULTS: The results indicate a decline in calcium solubility after laser irradiation. Compared to the control group, a 20% lower calcium content was detected in the demineralisation solution after irradiation with the Er:YSGG laser at 8 J/cm(2). The difference between the laser-irradiated groups and the untreated control group was, however, not statistically significant. A significantly lower calcium content was found in the demineralisation solution after fluoridation of the specimens. Additional laser radiation had no further effect on this result. CONCLUSIONS: In summary, it can be stated that, although the erbium laser wavelengths apparently have the potential to increase acid resistance, their application solely for caries prevention would not appear to be sensible under the prevailing conditions.

Analysis of Variance↗
PubMed2001

Interleukin-7 and infection itself by human immunodeficiency virus 1 favor virus persistence in mature CD4(+)CD8(-)CD3(+) thymocytes through sustained induction of Bcl-2.

The sequence of events and the mechanisms leading to the destruction of the thymus during human immunodeficiency virus (HIV) infection are still poorly characterized. Investigated here are the survival capacity on HIV-1 infection of the mature single-positive CD4(+)CD8(-)CD3(+) (SP CD4(+)) and the intermediate CD4(+) CD8(-)CD3(-) thymocytes previously shown to be able to replicate the virus in the thymic microenvironment. It is demonstrated that the mature SP CD4(+) thymocytes exhibit a high survival capacity despite the production of a high yield of viruses. Interleukin-7, reported to be a crucial cofactor of tumor necrosis factor (TNF) to promote HIV replication, is shown here to counteract the apoptotic activity of TNF. Resistance to apoptosis of SP CD4(+) cells is conferred by a high expression of the IL-7 receptor (IL-7R) associated with the capacity of IL-7 to permanently up-regulate Bcl-2. In addition, this high Bcl-2 level is further enhanced by infection itself. In contrast, intermediate thymocytes, which replicate the virus at a lower level, are more sensitive to apoptosis, and their differentiation into double-positive CD4(+)CD8(+)CD3(-) (DP CD3(-)) cells strongly increases their death rate on infection. This sensitivity is related to a lower expression of IL-7R and Bcl-2 in intermediate thymocytes, which further decreases at the DP CD3(-) stage. In addition, a decreased level of Bcl-2 is observed in this subset during infection. Altogether these data suggest that in vivo, HIV infection might create a persistent virus reservoir within the SP CD4(+) thymocytes, whereas the later infection of intermediate cells might lead to thymopoiesis failure.

Antigens, Differentiation, T-Lymphocyte↗
PubMed2001

Incremental validation of situational judgment tests.

Using 3 different samples, the authors assessed the incremental validity of situational judgment inventories (SJIs), relative to job knowledge, cognitive ability, job experience, and conscientiousness, in the prediction of job performance. The SJI was a valid predictor in all 3 samples and incrementally so in 2 samples. Relative to the other predictors, SJI's partial correlation with performance, controlling for the other 4 predictors, was superior in most comparisons. Subgroup differences on the SJI also appear to be less than those for cognitive ability and job knowledge, but greater than differences in conscientiousness. The SJI should prove to be a valuable additional measure in the prediction of job performance, but several additional areas of research are suggested.

Adult↗
PubMed2001

Traditional tests and job simulations: minority and majority performance and test validities.

Performance of 565 minority and 414 majority job applicants on traditional paper-and-pencil tests and on a telephone simulation that measured similar constructs was assessed. Models of the measurement characteristics of these 2 test batteries indicated larger subgroup mean differences on the traditional tests than on the simulation. Correlations between traditional tests were lower in the majority sample than in the minority sample, and the variance of the minority candidates' scores on the traditional tests was much larger than the variance of majority applicants' scores on the same measures. The validity of the simulation was lower than the validity of the traditional tests. This study replicates previous laboratory research that has indicated smaller subgroup differences on simulations than on paper-and-pencil tests and extends this research by providing evidence of the relative validity of these 2 types of measures.

Adult↗
PubMed2001

High-stakes testing in employment, credentialing, and higher education. Prospects in a post-affirmative-action world.

Cognitively loaded tests of knowledge, skill, and ability often contribute to decisions regarding education, jobs, licensure, or certification. Users of such tests often face difficult choices when trying to optimize both the performance and ethnic diversity of chosen individuals. The authors describe the nature of this quandary, review research on different strategies to address it, and recommend using selection materials that assess the full range of relevant attributes using a format that minimizes verbal content as much as is consistent with the outcome one is trying to achieve. They also recommend the use of test preparation, face-valid assessments, and the consideration of relevant job or life experiences. Regardless of the strategy adopted, it is unreasonable to expect that one can maximize both the performance and ethnic diversity of selected individuals.

Aptitude Tests↗
PubMed2000

A recessive C-terminal Jervell and Lange-Nielsen mutation of the KCNQ1 channel impairs subunit assembly.

The LQT1 locus (KCNQ1) has been correlated with the most common form of inherited long QT (LQT) syndrome. LQT patients suffer from syncopal episodes and high risk of sudden death. The KCNQ1 gene encodes KvLQT1 alpha-subunits, which together with auxiliary IsK (KCNE1, minK) subunits form IK(s) K(+) channels. Mutant KvLQT1 subunits may be associated either with an autosomal dominant form of inherited LQT, Romano-Ward syndrome, or an autosomal recessive form, Jervell and Lange-Nielsen syndrome (JLNS). We have identified a small domain between residues 589 and 620 in the KvLQT1 C-terminus, which may function as an assembly domain for KvLQT1 subunits. KvLQT1 C-termini do not assemble and KvLQT1 subunits do not express functional K(+) channels without this domain. We showed that a JLN deletion-insertion mutation at KvLQT1 residue 544 eliminates important parts of the C-terminal assembly domain. Therefore, JLN mutants may be defective in KvLQT1 subunit assembly. The results provide a molecular basis for the clinical observation that heterozygous JLN carriers show slight cardiac dysfunctions and that the severe JLNS phenotype is characterized by the absence of KvLQT1 channel.

Amino Acid Sequence↗
PubMed2000

Interindividual differences in intraindividual changes in proactivity during organizational entry: a latent growth modeling approach to understanding newcomer adaptation.

Intraindividual change over time is the essence of the change phenomenon hypothesized to occur in the individual newcomer adaptation process. Many important adaptation questions cannot be answered without an adequate conceptualization and assessment of intraindividual change. Using a latent growth modeling approach to data collected from 146 doctoral program newcomers over 4 repeated measurements spaced at 1-month intervals, the authors explicitly modeled interindividual differences in intraindividual changes in newcomer proactivities (information seeking, relationship building) and proximal adaptation outcomes (task mastery, role clarity, social integration) during organizational entry. Results indicated that changes in proactivity may be related to newcomer characteristics and adaptation outcomes in interesting ways that have not been previously examined.

Adaptation, Psychological↗
PubMed2000

Predictors of participation in health care at menopause.

Patient participation in health care is widely advocated but little is known about the factors influencing patients' active participation. To learn whether attitudes and beliefs helped predict patient participation, 252 midlife women completed measures of self-efficacy, perceived barriers to participation, attitudes, subjective norms, and intentions following a decision to support intervention on menopause. Two months following the intervention, 63 women who had visited a health care provider returned questionnaires by mail regarding self-reported participation in the health care encounter and satisfaction with the decision about estrogen replacement therapy. The results were that self-efficacy (beta = .19; p < .05) significantly predicted intention to participate in the next health care encounter. Both patient intentions (beta = .40;p < .05) and perceived barriers (beta = -.27; p < .05) were significant predictors of self-reported participation. Active participation (beta = .42;p < .05) and attitude (beta =.25;p < .05) were associated with increased satisfaction with decision. Participation resulted in increased self-efficacy (beta = .30;p < .05). The conclusions were that midlife women who express more confidence in their ability to participate in their health care have greater intentions to participate. Women who experience fewer barriers to participation and have more intention to participate are more likely to report actively participating in a health care encounter, and self-reported participation and more positive attitudes toward participation are associated with greater satisfaction with decisions.

Adult↗
PubMed1999

Parental employment, school climate, and children's academic and social development.

Longitudinal data were used to examine the effects of parental employment status and school climate on children's academic and social development. Hierarchical regression, analyses of covariance, and latent growth modeling were used to assess various aspects of change as a function of work status and school climate with family income and education as control variables. Parental employment was associated with positive changes in social and academic progress even after controlling for prior developmental level, climate, and family income although effects were small and complex. School climate had minimal effect on the outcome variables. Income and education were related to various school outcomes.

Adult↗
PubMed1999

Patient decision support intervention: increased consistency with decision analytic models.

BACKGROUND: Patient Decision Support (PDS) tools assist patients in using medical evidence to make choices consistent that are with their values and in using evidence about consequences of medical alternatives. OBJECTIVE: To evaluate a PDS intervention for perimenopausal hormone replacement therapy. We assessed the impact of the PDS on (1) consistency between the decision to take estrogen replacement therapy (ERT) or progesterone/estrogen replacement therapy (PERT) and the expected utility of treatment and (2) likelihood to take ERT and PERT pre- and postintervention. DESIGN: Content of the PDS was standardized. Randomized trial of three intensities of intervention: (1) brochure; (2) lecture/discussion; and (3) active decision support. SUBJECTS: Participants were perimenopausal community volunteers between the ages of 40 and 65 (n = 248). MEASURES: (1) Consistent with values (correlation between expected utility (EU) and likelihood of taking hormones); and (2) Likelihood to take hormone replacement therapy. RESULTS: (1) The brochure group was less consistent with the decision analytic model than the lecture/discussion and active decision support groups. (2) Influence on decisions: PDS tools increased the number of women certain about whether or not to take hormones. There were no differences among experimental groups. Of 99 women uncertain about ERT pre-PDS, 65% changed. Twenty-one (32%) decided against ERT and 44 (68%) decided for ERT. (3) More intensive interventions produced modest gains in a normative direction. CONCLUSIONS: PDSs using any of 3 formats reduce uncertainty and assist women to make informed decisions. Increased consistency with decision analytic models appears to be driven by better estimates of likelihood of outcomes.

Adult↗
PubMed1998

Understanding pretest and posttest reactions to cognitive ability and personality tests.

To understand the nature of test reactions and their relationship to test performance, the relationships among belief in tests, pretest reactions, test performance, and posttest reactions were modeled for cognitive ability and personality tests. Results from structural equation models that were fitted to responses from 197 undergraduate examinees supported the hypothesized relationships. On the cognitive ability test, pretest reactions affected test performance and mediated the relationship between belief in tests and test performance. Test performance affected posttest reactions even after taking into account the effect of pretest reactions. On the personality test, belief in tests affected pretest and posttest reactions, but the three variables were unrelated to test performance (Conscientiousness scores). Conceptual, methodological, and practical implications of the findings are discussed in the context of research on test reactions and test performance.

Cognition↗
PubMed1997

An educational intervention as decision support for menopausal women.

The purpose of this study was to develop and test a decision support intervention (DSI) to assist women to make and act on informed decisions that are consistent with their values in the area of menopause and hormone replacement therapy (HRT). Mode and intensity of intervention were tested in midlife women (N = 248), randomly assigned to one of three intervention formats: written information only, guided discussion, or personalized decision exercise. Data were collected over 12 months. Knowledge, decisional conflict, satisfaction with health care provider, and self-efficacy improved following intervention and were maintained for 12 months for all groups. Women's adherence to their own plans over 12 months was 59% (exercise), 76% (calcium intake), and 89% (HRT). Carefully written information is effective in promoting knowledge, adherence, and satisfaction among well-educated, interested women. It was concluded that women can understand complex information, including tradeoffs regarding treatment options. Women will adhere to their own plans, suggesting that consumer rather than provider plans may be the more appropriate gold standard for measuring adherence.

Adult↗
PubMed1997

Video-based versus paper-and-pencil method of assessment in situational judgment tests: subgroup differences in test performance and face validity perceptions.

On the basis of a distinction between test content and method of testing, the present study examined several conceptually and practically important effects relating race, reading comprehension, method of assessment, face validity perceptions, and performance on a situational judgement test using a sample of 241 psychology undergraduates (113 Blacks and 128 Whites). Results showed that the Black-White differences in situational judgment test performance and face validity reactions to the test were substantially smaller in the video-based method of testing than in the paper-and-pencil method. The Race x Method interaction effect on test performance was attributable to differences in reading comprehension and face validity reactions associated with race and method of testing. Implications of the findings were discussed in the context of research on adverse impact and examinee test reactions.

Black or African American↗
PubMed1997

Reactions to cognitive ability tests: the relationships between race, test performance, face validity perceptions, and test-taking motivation.

The relationships among race, face validity perceptions, test-taking motivation, and test performance on a cognitive ability test were examined. Undergraduates completed 2 parallel cognitive ability tests and a test reactions measure. Results showed that test-taking motivation was related positively to subsequent performance on a parallel test even after the effects of race and performance on the first test were controlled. The effect of race on subsequent test performance was found to be mediated partially by motivation that provided evidence that some portion of the Black-White difference in test performance may be explained through differences in test-taking motivation. Results also indicated that Black-White differences in face validity perceptions of the test may be a function of Black-White differences in test performance. Face validity perceptions of the test affected subsequent performance on the parallel test but only indirectly through test-taking motivation.

Achievement↗
PubMed1995

Does calmitine, a protein specific for the mitochondrial matrix of skeletal muscle, play a key role in mitochondrial function?

The effect of the myotoxic drug chlorpromazine was studied in vitro on proteins of sarcoplasmic reticulum and mitochondrial matrix of skeletal muscle in the normal mouse. Our results indicate that the drug is specific for calcium-binding proteins (calcium ATPase, calsequestrin and calmitine). Its proteolytic effect on these proteins, apparently due to the stimulation of specific proteases, could account for its myotoxic action. Moreover, calsequestrin (sarcoplasmic reticulum) and calmitine (mitochondrial matrix) were not sensitive to the same proteases. Proteases acting on calmitine were inhibited by alpha 2-macroglobulin but not those acting on calsequestrin. Despite some similarities between these two proteins, their characteristics of localization and sensitivity of their proteases indicate that calmitine has a specificity within the mitochondrial matrix and very probably plays a major role in the mitochondrial regulation of free calcium, which controls the activity of various enzymes of the mitochondrial matrix involved in ATP synthesis.

Animals↗