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PubMed2005

Refined estimate of the incubation period of severe acute respiratory syndrome and related influencing factors.

Many epidemiologists have agreed that a refined estimate of the incubation period of severe acute respiratory syndrome (SARS) would need a sample size of about 200 cases and appropriate statistical methods enabling the inclusion of cases with defined periods of exposure. However, no such studies have been reported so far. Besides, determinants of the SARS incubation period remain unclear. In this study, 209 probable SARS cases with documented episodes of exposure between March 1 and May 31, 2003, in mainland China were included. A nonparametric method was used to analyze these data with defined periods of exposure to obtain the refined estimate of the SARS incubation period. Furthermore, the authors also explored the influence of various factors on the SARS incubation period by analysis of variance, linear regression analysis, and analysis of covariance. The estimates of mean and variance of the SARS incubation period were 5.29 days and 12.33 days(2), respectively; 90% of patients would have an incubation period of less than 11.58 days with a probability of 0.8, and 99% of patients would have an incubation of less than 22.22 days with a probability of 0.9. The affected area showed a highly significant effect on the incubation period (p < 0.001), but the contact pattern, occupation, gender, and age did not.

Analysis of Variance↗
PubMed2002

Morphometric analysis of nonadult characters of common species of American gordiids (Nematomorpha: Gordioidea).

The nonadult stages, egg strings, eggs, larvae, and cysts of Gordius robustus, Paragordius varius, and Chordodes morgani are described morphometrically. The goal was to document the differences between species and to evaluate the usefulness of morphometrics in species identification. In concert, multivariate analysis of variance (MANOVA) and univariate analysis of variance (ANOVA, a posteriori contrasts) statistical tests demonstrated that each species is morphometrically distinguishable from all others. Additionally, discriminant function analysis indicated that postseptum length, pseudointestine length, and stylet width were the most important variables in the discrimination of species based on larval characters. Finally, differences in oviposition behaviors among these 3 species were found. It is suggested that ovipositioning differences may place larvae into distinct niches and may ultimately lead to the use of different paratenic hosts by different gordiid species.

Animals↗
PubMed2002

Allograft implants for posterior lumbar interbody fusion: results comparing cylindrical dowels and impacted wedges.

OBJECTIVE: With the proliferation of implant types available for use in posterior lumbar interbody fusion (PLIF) procedures, the choices for surgeons have become increasingly complex. The goal of this study was to retrospectively review a series of 49 patients who underwent PLIF with the use of allograft cylindrical threaded cortical bone dowels (TCBDs) and allograft impacted wedges. Nerve root injury rates, fusion rates, and clinical outcomes of the allograft impacted wedge group are compared with those in the allograft cylindrical TCBD group. METHODS: We performed a retrospective chart and radiographic review of 49 patients. Twenty-seven patients underwent PLIF with impacted allograft wedges, and 22 patients underwent PLIF with allograft cylindrical TCBD. Permanent nerve root injury rates, fusion rates, and clinical outcomes were assessed on the basis of a minimum of 1 year of follow-up data in this nonconsecutive series. RESULTS: Permanent nerve root injuries in the impacted wedge and TCBD groups were documented with physical examinations conducted pre- and postoperatively. The cylindrical TCBD group showed a 13.6% rate of permanent nerve root injury, and the impacted wedge group demonstrated a 0% rate, and these rates were statistically significant (analysis of variance, P = 0.049). The fusion rate at a mean of 13.9 months of follow-up was 95.4% in patients in whom the cylindrical TCBD was implanted and 88.9% after a mean of 17.4 months of follow-up in patients in whom impacted wedges were used. The fusion rate difference between the TCBD and impacted wedge groups was not significant. The satisfactory outcome rate was 72.7% for the TCBD group and 85.1% for the impacted wedge group, and the impacted wedge group was found to have a significantly higher rate of satisfactory outcomes (P = 0.016, analysis of variance). Analysis of the patient outcomes in the TCBD and impacted wedge groups according to sex, mean length of follow-up, workman's compensation claim rate, and smoking habit yielded no significant difference. CONCLUSION: With a minimum of 1 year of follow-up in this nonconsecutive series of 49 patients, a comparison of the use of allograft TCBD versus allograft impacted wedges in PLIF procedures reveals a statistically significant increase in permanent nerve root injury rates with the use of cylindrical TCBD implants as compared with impacted allograft wedges. There is no difference between the two groups in terms of fusion rates, and clinical outcomes with the use of impacted wedges were significantly better.

Adolescent↗
PubMed1993

Analytical methods to differentiate similar electroencephalographic spectra: neural network and discriminant analysis.

Differences in electroencephalographic (EEG) power spectra obtained under similar, but not identical, conditions may be difficult to discern using standard techniques. Statistical analysis may not be useful because of the large number of comparisons necessary. Visual recognition of differences also may be difficult. A new technique, neural network analysis, has been used successfully in other problems of pattern recognition and classification. We examined a number of methods of classifying similar EEG data: standard statistical analysis (analysis of variance), visual recognition, discriminant analysis, and neural network analysis. Twenty-nine volunteers received either thiopental (n = 9), midazolam (n = 10), or propofol (n = 10) in sedative doses in 3 different studies. These drugs produced very similar changes in the EEG power spectra. Except for beta 2 power during thiopental infusion, differences between drugs could not be detected using analysis of variance. Visual categorization was correct in 72% of the baseline EEGs, 70% of thiopental EEGs, 27% of propofol EEGs, and 46% of midazolam EEGs. A classification neural network (Learning Vector Quantization network) containing a Kohonen hidden layer was able to successfully classify 57 of 58 EEG samples (of 4 minutes' duration). Discriminant analysis had a similar rate of success. This level of performance was achieved by dividing the EEG power spectrum from 1 to 30 Hz into 15 2-Hz bandwidths. When the EEG power spectrum was divided into the "classical" frequency bandwidths (alpha, beta 1, beta 2, theta, delta), both neural network and discriminant analysis performance deteriorated. By training the network using only certain inputs we were able to identify drug-specific bandwidths that seemed to be important in correct classification. We conclude that propofol, thiopental, and midazolam produce different effects on the EEG and that both neural network and discriminant analysis are useful in identifying these differences. We also conclude that EEG spectra should be analyzed without using classical EEG bands (alpha, beta, etc.). Additionally, neural networks can be used to identify frequency bands that are "important" in specific drug effects on the EEG. Once a classification algorithm is obtained using either a neural network or discriminant analysis, it could be used as an on-line monitor to recognize drug-specific EEG patterns.

Adult↗
PubMed2006

[Haemocoagulative modifications correlated with pregnancy].

AIM: The aim of this paper was to establish the physiologic changes in the coagulation and fibrinolytic systems during normal pregnancy. METHODS: One-hundred and twenty normal pregnant women were investigated in a longitudinal study involving 3 measurements: blood samples were collected at 12, 24 and 36 weeks of gestation and were assayed for prothrombin time, antithrombin III (ATIII) activity, protein C activity, protein S (PS) activity, prothrombin fragments 1+2, type 1 plasminogen activator inhibitor activity, tissue plasminogen activator antigen, plasminogen, activated protein C resistance, factors VII and VIII levels and D dimer. Student t-test, one way analysis of variance (ANOVA) and Fisher test were used for statistical analysis. RESULTS: Factor VII and factor VIII were always increased with respect to controls. Variance analysis showed a statistically significant reduction for anticoagulants (PS) and a rise for F1+2 and D dimer. With regard to fibrinolysis, there was an increase both for t-PA and PA1-1 during pregnancy. Moreover, the increased activity of factors of haemostasis was accompanied by an increase of activity and concentration of ATIII and acquired activated protein C resistance. CONCLUSIONS: These findings suggest that normal pregnancy is associated with an hypercoagulable state, resulting into a moderate risk for thrombosis during the different trimesters of pregnancy. Also broad spectrum assays which measure a range of trombin/fibrin formation in serum have become an established mean to identify activation of blood coagulation and/or fibrinolysis. There is a considerable interest in the application of these assays to the diagnosis of other acquired hypercoagulable states; such as thrombophilia during pregnancy. From the viewpoint of coagulation/fibrinolysis changes, the follow-up of thrombophilia markers could be recommended when levels of coagulation parameters exceed the normal values during pregnancy.

Adult↗
PubMed1991

Correlation of preoperative factors, severity of disease, type of oxygenator and perfusion times with mortality and morbidity of coronary bypass.

Previous studies have related preoperative status and severity of disease to the outcome of coronary artery bypass surgery. Although increased perfusion and clamp times increase the risk of cardiac surgical procedures, the importance of these factors in relation to the patient's preoperative condition and the severity of disease has not previously been determined. In this study of 1078 patients, we examined the correlation between the patient's preoperative condition, the severity of coronary disease, and duration of perfusion and clamp time, and the type of oxygenator used with the mortality and morbidity associated with coronary artery bypass grafting. One-way analysis of variance and multiple correlation analysis showed that perfusion time, clamp time and nonclamp perfusion time correlated with mortality, perioperative infarction, the use of intra-aortic balloon pump, stroke, renal failure, pulmonary failure, infection, and leg wound complications (p less than 0.05). Perfusion time, clamp time and nonclamp perfusion time did not correlate with postoperative bleeding or sternal wound complications. Nonclamp perfusion time correlated more strongly than any other factor with mortality, perioperative infarction, the use of intra-aortic balloon pump, renal failure, pulmonary failure and infection (p less than 0.05). Clamp time correlated more than any other factor with the development of leg-wound complications (p less than 0.05). The use of a bubble rather than a membrane oxygenator was significantly related to mortality, stroke, infection and leg wound complications by one-way analysis of variance (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Uncomplicated intraventricular hemorrhage is followed by reduced cortical volume at near-term age.

BACKGROUND: Intraventricular hemorrhage (IVH) is the most common brain injury among premature infants. Neonates with IVH are at greater risk of impaired neurodevelopmental outcomes, compared with those without IVH. IVH causes destruction of the germinal matrix and glial precursor cells, with possible effects on cortical development. OBJECTIVE: To investigate cortical development after uncomplicated IVH (with no parenchymal involvement and no posthemorrhagic hydrocephalus). We hypothesized that uncomplicated IVH would be followed by reduced cortical volume among premature infants at near-term age. METHODS: A prospective cohort study was conducted, with preset selection criteria. Infants with small-for-gestational age birth weight, congenital abnormalities or brain malformations, metabolic disorders, recurrent sepsis, or necrotizing enterocolitis were excluded. Also, infants with posthemorrhagic hydrocephalus, parenchymal involvement of hemorrhage, cystic periventricular leukomalacia, or persistent ventriculomegaly were excluded, on the basis of routine serial ultrasonographic assessments. Three-dimensional images were acquired for 23 infants at near-term age, with 3-T magnetic resonance imaging and a magnetization-prepared rapid gradient echo sequence. Image analysis and segmentation of the cerebrum in different tissue types were based on signal contrast and anatomic localization. The cortical gray matter (CGM), subcortical gray matter, white matter, and intraventricular cerebrospinal fluid volumes of 12 infants with uncomplicated IVH were compared with those of 11 infants without IVH, using multivariate analysis of variance. RESULTS: The multivariate analysis of variance for the regional brain volumes in the 2 groups indicated significance (Wilks' lambda = 0.546). The CGM volume was significantly reduced in the IVH group (no-IVH group: 122 +/- 12.9 mL; IVH group: 102 +/- 14.6 mL; F = 13.218). This finding remained significant after testing for possible confounding factors and adjustment for size differences between the infants (F = 9.415). There was no difference in the volumes of subcortical gray matter, white matter, and cerebrospinal fluid. CONCLUSIONS: This is the first study to document impaired cortical development after uncomplicated IVH. The impairment was demonstrated by a 16% reduction in cerebral CGM volume at near-term age. The finding supports concerns regarding possible glial precursor cell loss after germinal matrix IVH, but its clinical significance is still unclear. The alteration in brain development demonstrated in this report supports closer neurodevelopmental follow-up monitoring of preterm infants with uncomplicated IVH.

Brain Diseases↗
PubMed1993

The effects of competitive anxiety on memory span and rebound shooting tasks in basketball players.

Two theoretical models were used to investigate aspects of basketball performance: Eysenck's (1979, 1984) compensatory arousal model and Humphreys and Revelle's (1984) twin resources model. Cognitive and somatic anxiety were manipulated using a 'time to event' paradigm. The aspects of performance were a short-term memory task (letter span) and a low memory demand, motoric-sustained information transfer task (rebound shooting). Hypotheses based on the different models were formulated and subsequently tested using analysis of variance and polynomial regression analysis. The results indicated significant (P < 0.01) linear relationships with negative slopes between cognitive anxiety and letter span, and between somatic anxiety and letter span; while significant (P < 0.01) linear relationships with positive slopes were recorded between cognitive anxiety and rebound shooting, and between somatic anxiety and rebound shooting. The analysis of variance results were in agreement with a positive effect (P < 0.05) for cognitive anxiety upon rebound shooting, and a negative effect which approached significance (P < 0.07) for somatic anxiety upon letter span. The results were interpreted as offering partial support for Eysenck's (1979) theoretical model, although further examination of multidimensional anxiety effects via the two models is warranted.

Adult↗
PubMed2003

Clinical presentation of pertussis in unvaccinated and vaccinated children in the first six years of life.

OBJECTIVES: Identifying the determinants of the clinical presentation of pertussis is important for the purposes of diagnosis, therapy, and control and for predicting the disease's clinical course and choosing an appropriate case definition for surveillance. Potential determinants include vaccination status, antibiotic treatment, age at diagnosis, and sex, although the available data are inconsistent. The objective of this study was to compare the clinical course of pertussis in unvaccinated and vaccinated children in a well-defined and strictly studied population and to identify determinants of the disease's clinical presentation. METHODS: The clinical presentation of pertussis was studied in children who participated in a randomized, controlled clinical trial of efficacy of acellular pertussis vaccine. The children belonged to the same birth cohort and were followed from infancy to 6 years of age in 3 distinct periods (stages 1, 2, and 3). Children had received 1 of 2 three-component acellular pertussis vaccines produced by 2 manufacturers (diphtheria-tetanus-acellular pertussis from, Chiron Biocine [DTaP CB]; DTaP from SmithKline Beecham [DTaP SB]) or a diphtheria-tetanus vaccine only (DT; Chiron Biocine). Pertussis was confirmed through culture or serology. For each pertussis episode, information was collected on age at onset, sex, type of vaccine received, antibiotic treatment, culture results, duration of cough, spasmodic cough, and other symptoms. The simultaneous effect of potential determinants of clinical presentation of pertussis on the duration of cough and spasmodic cough was studied through analysis of variance models. RESULTS: The analysis was conducted on 788 laboratory-confirmed cases of pertussis. The median duration of cough in DT recipients varied from 52 to 61 days across the 3 stages, whereas the median duration of cough in DTaP recipients varied from 29 to 39 days. The median duration of spasmodic cough varied from 20 to 45 days in DT recipients and from 14 to 29 days in DTaP recipients. The results of the analysis of variance models showed that vaccination against pertussis reduced the length of cough from 3 to 10 days and the length of spasmodic cough from 4 to 8 days. Culture-positive patients had a cough 11 to 22 days longer and a spasmodic cough 12 to 22 days longer than culture-negative patients. Children who received an antibiotic had a duration of cough 6 to 11 days longer and spasmodic cough 4 to 13 days longer than untreated patients. Girls had a duration of spasmodic cough 7 days longer than boys only after 3 years of age. Age was directly related to duration of cough, whereas it was inversely related to duration of spasmodic cough after 3 years of age. CONCLUSIONS: Duration of cough can be greatly influenced by vaccination status. A positive culture for Bordetella pertussis is more frequently found in patients with long duration of cough, and antibiotic therapy may be a marker of severe disease. Gender may affect the clinical presentation of pertussis only after infancy. Pertussis in older children may be characterized by short duration of spasmodic cough. These results should be taken into account in the clinical evaluation of patients with suspected pertussis. Clinical case definitions for the purpose of surveillance based on the presence of 2 weeks of spasmodic cough may not be appropriate where pertussis vaccination uptake is high.

Child, Preschool↗
PubMedDate not supplied

Learning styles and outcomes in clinical laboratory science.

OBJECTIVE: To compare two learning styles--reflective observation versus active experimentation--in terms of learning outcomes. DESIGN: The independent variable, student learning styles, was generally defined as styles determined by use of the Kolb's Learning Style Inventory. The styles were identified as either active experimentation or reflective observation. The dependent variables were learning outcomes that were determined by two methods: the average score on eight posttests scheduled at periodic intervals and a national certification examination score. SETTING: Clinical laboratory science education program at the University of Nebraska Medical Center in Omaha and at six clinical sites in other cities across Nebraska. PARTICIPANTS: Forty senior clinical laboratory science students enrolled in a baccalaureate degree program. MAIN OUTCOME MEASURES: Data analysis consisted of descriptive statistics, two-way analysis of variance, two-way analysis of covariance, and repeated measures analysis of variance. RESULTS: Results showed no significant difference between the students' examination scores based on learning styles. There was no significant difference in the pattern of the examination scores over the semester of learners who were active experimenters versus reflective observers. CONCLUSION: Results of the study generally did not support the conclusions of the earlier research; students' learning styles did not affect their examination scores. No pattern in the examination scored exists in the learning style groups.

Clinical Laboratory Techniques↗
PubMed2005

A study to assess the colour stability of acetal resins subjected to thermocycling.

The purpose of this study was to compare colour stability of pink and white acetal resin with one conventional poly (methylmethacrylate) resin. Five specimen disks 50 +/- 0.1 mm in diameter and approximately 1.0 mm thick were prepared from each material. The discs were hydrated for a period of 30 days in distilled water and were then desiccated to a constant weight. Total of fifteen specimens were thermocycled for 100 and 300 hours (4000-12000 cycle) between water baths of 5-55 degrees C. Changes from baseline colour readings were recorded at each interval. Data were analysed with descriptive statistic, repeated measured analysis of variance and single factor analysis of variance. The colour changes for all materials at 100 hours were in the categories of slight, based upon the National Bureau of Standard System (NBS) for expressing colour difference. At 300 hours, the colour changes of materials were significantly different (p = 0.0001). All the materials tested showed clinically acceptable discolouration values.

Color↗
PubMed1990

Statistical analysis of repeated measures in psychiatric research.

We examined the statistical methods applied to research studies that used parallel-groups repeated measures designs. Sixty-three of the 343 articles that were published in four major psychiatry research journals during a 6-month period contained data of this type. Seven (11%) of the 63 articles applied a multivariate analysis of variance. Four (6%) used a univariate analysis of variance with an adjustment for correlated measures. Ten (16%) used a univariate analysis of variance without an adjustment for correlated measures. Twenty (32%) either reduced their repeated measurements to a single value, such as a maximum-change score in each group, or carried out multiple tests at several time points. Twenty-two (35%) of the reports did not provide enough information to allow readers to determine the type of analysis that was applied. We discuss the appropriate selection of analytical techniques for repeated measures designs.

Humans↗
PubMed1999

Changes in the work and motivation of staff delivering home care services in Finland.

This article describes how the policy to emphasize noninstitutional care is reflected in home care service strategies and work characteristics as well as the work motivation of home care staff in Finland. The data were gathered through a questionnaire answered by 312 employees in home care services and 22 social welfare and primary health care administrators. The methods of analysis used were cross-tabulations, one-way analysis of variance, and regression analysis. According to the results, institutional care had been reduced too fast and home care services had not been developed sufficiently. Most of the staff reported that their work had changed considerably. Although their work had become more interesting and more independent, over one third of the employees felt that the pressure of work had become unbearable and their responsibility was too heavy. The views of the home care staff differed from those of the administrators regarding the change strategies that had been carried out. The majority of the staff were moderately or highly motivated. Thirty-four percent of the variance of work motivation was explained mainly by work characteristics. More attention should be paid to the development of home care services before institutional care is reduced. Training the staff and informing them about the planned reform should not be neglected.

Analysis of Variance↗
PubMed2004

Cultural consistency in Australian dental students from two different ethnic backgrounds.

The objective of this study was to examine the value orientations of dental students from different ethnic backgrounds studying in Australian dental schools. A ninety-eight-item questionnaire was used to collect the data, including fifteen subscales developed consistent with the Kluckhohn and Strodtbeck value orientation model. To compare the value orientation structure and to determine if any ethnic differences existed, a multivariate analysis of variance called profile analysis was performed on the fifteen value subscales. Of the 401 participants, 30.2 percent were Anglo-Australian and 44.9 percent were Asian. The remainder (24.9 percent) were "Other-background residents" or "Other-international students." This article presents data from Asian (n=184) and Anglo-Australian (n=124) background respondents. Mean age was 21.7 years (s.e. 0.35 years) among Anglo-Australian and 20.8 years (s.e. 0.17 years) among Asians. Asians born overseas represented 70.7 percent (n=130) of this group. Of Australia-born Asians (n=54), 90.6 percent were first-generation Australians. When comparing their value profile, we found a significant association between ethnicity and value orientation profile scores (p<0.05). Despite the significant overall result, the strength of the association (eta(2)=0.007) indicated that this effect was trivial relative to the unexplained variance in value orientation. The findings suggest that, behind an apparent ethnic diversity, a single distinctive value profile might exist to which the majority of dental students subscribe.

Adult↗