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PubMed2002

Cardiovascular and respiratory consequences of bilateral involvement of the medullary intermediate reticular formation in syringobulbia.

We studied five patients with clinical and radiological evidence of syringobulbia (SB) to determine whether the distribution of lesions in relationship to the cardiorespiratory control networks in the medullary intermediate reticular zone (IRt) correlates with the presence of abnormalities in autonomic cardiovascular and respiratory control in these patients. All patients underwent high resolution MRI to characterize the size, volume and distribution of the SB lesions, cardiovascular autonomic function testing and polysomnography. One patient with bilateral IRt involvement at both the rostral and caudal medulla had orthostatic hypotension (OH), absent HR(DB), abnormal Valsalva ratio, exaggerated fall of BP during phase II and absent phase IV during VM, and a dramatic fall of BP during head up tilt; this patient also had severe obstructive sleep apnea (OSA) and exhibited BP drops during each respiratory effort. A second patient, with bilateral IRt involvement restricted to the caudal medulla, had less severe cardiovascular autonomic dysfunction but also exhibited severe OSA. The other three patients had small SB cavities sparing the IRt and had sleep apnea but no autonomic dysfunction. Autonomic dysfunction could not be related to the size of the syrinx or the degree of atrophy in the cervical spinal cord in any of the five patients. Bilateral involvement of the IRt by SB produces cardiovascular autonomic failure and sleep apnea. In patients with more restricted lesions, autonomic and respiratory dysfunction may be dissociated. Clinico-radiological correlations using high resolution MRI assessment of medullary lesions can provide insight into the central organization of cardiovascular and respiratory control in humans.

Adult↗
PubMed1986

Trypsin-like activity and thromboxane release in adult respiratory distress syndrome.

Plasmatic immunoreactive trypsin (IRT), thromboxane and trypsin-like enzymatic activity were measured in 117 patients at risk of developing adult respiratory distress syndrome (ARDS) (53 multiple injury, 30 abdominal surgery, 17 acute pancreatitis, 12 burnt and 5 disseminated intravascular coagulation patients). 69 of these patients developed ARDS. Immunoreactive trypsin and thromboxane were measured by radio-immuno-assay and trypsin-like enzymatic activity by spectrophotometry, using a specific chromogenic substrate. Mean IRT value was 675 ng/ml in ARDS and 265 ng/ml in non ARDS patients (p less than 0.05). Mean IRT value was 685 ng/ml in septic and 170 ng/ml in non septic patients (p less than 0.01). An abnormal trypsin-like enzymatic activity was measured in 26 ARDS patients. In 60 patients (37 ARDS and 23 non ARDS), thromboxane appeared in plasma simultaneously or about 24 hours after the beginning of IRT release. The importance of thromboxane release parallels the intensity of IRT. Originating from pancreas, trypsin can appear in plasma either by absorption from gastrointestinal tract or after pancreatic ischemia.

Clinical Enzyme Tests↗
PubMed1988

Interstitial radiation therapy in the treatment of childhood soft-tissue sarcomas.

Between 1971 and 1985, 12 children and adolescents aged 0.7 to 19 years (median 4.7 years) with localized residual soft-tissue sarcomas (STS) underwent interstitial radiation therapy (IRT) at our institution. Eight received IRT as a component of initial therapy, and four were treated for recurrent or persistent disease. Tumor sites were head and neck (6), pelvis (4), extremity (1), and retroperitoneum (1). The radionuclides employed were Iridium-192 (9), Iodine-125 (2), and Californium-252 (1). The median prescribed dose in the Iridium-192 group was 3960 cGy (1955-7300). Seven of eight children receiving IRT during initial therapy have maintained local control, and six remain without evidence of disease for a median follow-up time of 5.8 years (2.0-16.0). One of the four patients treated for recurrent disease is free of disease after salvage surgery, and the other three are dead of disease. Multidisciplinary evaluation of the nine patients with more than 2 years of follow-up revealed functional and cosmetic effects of IRT to be minimal. IRT can be an effective method of delivering high dose irradiation in childhood sarcomas while reducing the deleterious effects in adjacent normal tissues.

Adolescent↗
PubMed1996

Phase III study of interstitial thermoradiotherapy compared with interstitial radiotherapy alone in the treatment of recurrent or persistent human tumors. A prospectively controlled randomized study by the Radiation Therapy Group.

PURPOSE: The objectives of this randomized trial were to determine if interstitial thermoradiotherapy (ITRT) improves tumor regression/control in accessible lesions in comparison with interstitial radiotherapy (IRT) alone and to assess the skin and soft tissue complications with either modality. METHODS AND MATERIALS: From January 1986 to June 1992, 184 patients with persistent or recurrent tumors after previous radiotherapy and/or surgery, which were amenable to interstitial radiotherapy, were accessioned to a protocol developed by the Radiation Therapy Oncology Group (RTOG). One hundred seventy-three cases were analyzed (87 patients in the IRT group and 86 in the ITRT arm). The two arms were well balanced regarding stratification criteria. Most tumors were in the head and neck (40% in the IRT group and 46% in the ITRT group), and pelvis (42% and 43%, respectively). Eighty-four percent of patients in both arms had prior radiation therapy (> or = 40 Gy); 50% and 40%, respectively, had prior surgery, and 34% in each arm had prior chemotherapy. The dose of radiation therapy administered was dependent on the previous radiation dose and did not exceed a total cumulative dose of 100 Gy. Hyperthermia was delivered in one or two sessions, either before or before and after interstitial implant. The intended goal of the hyperthermia was to maintain a minimal tumor temperature of 42.5 degrees C for 30 to 60 min. RESULTS: There was no difference in any of the study end points between the two arms. Complete response (CR) was 53% and 55% in both arms. Two-year survival was 34% and 35%, respectively. Complete response rate for persistent lesions was 69% and 63% in the two treatment arms as compared with 40% and 48% for recurrent lesions. A set of minimal adequacy criteria for the delivery of hyperthermia was developed. When these criteria were applied, only one patient had an adequate hyperthermia session. Acute Grade 3 and 4 toxicities were 12% for IRT and 22 % for ITRT. Late Grade 3 and 4 toxicities were 15% for IRT and 20% for ITRT. The difference was not significant. CONCLUSIONS: Interstitial hyperthermia, as applied in this randomized study, did not show any additional beneficial effects over interstitial radiotherapy alone. Delivery of hyperthermia remains a major obstacle (since only one patient met the basic minimum adequacy criteria as defined in this study). The benefit of hyperthermia in addition to radiation therapy still remains to be proven in properly randomized prospective clinical trials after substantial technical improvements in heat delivery and dosimetry are achieved.

Adult↗
PubMed2004

[Novel Doppler indexes of estimation of pulmonary capillary pressure: influence of age, feasibility in the acute setting and reproducibility].

BACKGROUND: The Doppler indexes E/Vp, E/Ea, 1000/(2 x IRT + Vp), 1000/(2 x IRT + Ea) and DTd (E: peak E mitral velocity; Vp: flow propagation velocity by color M-mode; Ea: peak early diastolic velocity at lateral mitral annulus by tissue Doppler; IRT: isovolumic relaxation time; DTd: deceleration time of the pulmonary venous diastolic wave) have been proposed for the non-invasive prediction of left ventricular filling pressures. However, the influence of age, the feasibility in acute setting and the reproducibility of these Doppler indexes have never been simultaneously investigated. OBJECTIVE: The present study was conducted to evaluate the influence of age in 56 healthy subjects (57 +/- 20 years of age), the feasibility in 40 critically ill patients (72 +/- 13 years of age; 21 with decompensated heart failure) and the reproducibility in 15 patients. RESULTS: Only the indexes E/Vp (R = 0.37, P = 0.005) and E/Ea (R = 0.72, P < 0.001) were correlated with age. The feasibility was 92, 90, 72, 72 and 45% for E/Ea, 1000/(2 x IRT + Ea), E/Vp, 1000/(2 x IRT +Vp) and DTd, respectively. The best reproducibility was observed for the Doppler parameters E and Ea. CONCLUSION: Despite it is influenced by age, E/Ea appears to be the most useful index for predicting left ventricular filling pressures routinely.

Adolescent↗
PubMed2005

Scoring based on item response theory did not alter the measurement ability of EORTC QLQ-C30 scales.

BACKGROUND AND OBJECTIVES: Most health-related quality-of-life questionnaires include multi-item scales. Scale scores are usually estimated as simple sums of the item scores. However, scoring procedures utilizing more information from the items might improve measurement abilities, and thereby reduce the needed sample sizes. We investigated whether item response theory (IRT)-based scoring improved the measurement abilities of the EORTC QLQ-C30 physical functioning, emotional functioning, and fatigue scales. METHODS: Using a database of 13,010 subjects we estimated the relative validities of IRT scoring compared to sum scoring of the scales. RESULTS: The mean relative validities were 1.04 (physical), 1.03 (emotional), and 0.97 (fatigue). None of these were significantly larger than 1. Thus, no gain in measurement abilities using IRT scoring was found for these scales. Possible explanations include that the items in the scales are not constructed for IRT scoring and that the scales are relatively short. CONCLUSION: IRT scoring of the three longest EORTC QLQ-C30 scales did not improve measurement abilities compared to the traditional sum scoring of the scales.

Adult↗
PubMed2006

Applying the item response theory to classroom examinations.

OBJECTIVE: The purpose of this research project was to determine if the item response theory (IRT) can successfully be applied to smaller-sized class examinations. METHODS: The Rasch mathematical model (RMM) was selected from the family of IRT models because of its ability to work with smaller sample sizes. Two simulated examinations were created for 100 students by 100-item dichotomous examinations. Examination 2 contained 20 items common with those in examination 1. Examination 1 was systematically exposed to randomly missing student responses and to entire items being removed to determine the robustness of the RMM to missing data. The two examinations were then analyzed with the RMM individually and then in combination. Student scores and IRT measures were compared to determine if the IRT could successfully place the students from the two examinations on the same metric of measure. RESULTS: The student measures were not affected when up to 20% of the student responses were randomly missing. Student measures continued to have high reliability and correlated with full matrix measures for up to 40% of items being dropped from the examination. Student scores and IRT measures correlated highly when the two examinations were combined. CONCLUSIONS: The RMM can be successfully applied to small-sized class examinations, such as those at chiropractic, medical, and other health profession institutions. It is possible to place candidates from different administrations on the same metric of measure if there is as little as a 20% overlap of items between examinations. The RMM could assist faculty in determining if differences in candidate scores are caused by ability or item difficulty.

Chiropractic↗
PubMed2005

Combining immunoreactive trypsinogen and pancreatitis-associated protein assays, a method of newborn screening for cystic fibrosis that avoids DNA analysis.

OBJECTIVES: To evaluate the performance of a strategy in which, after immunoreactive trypsinogen (IRT) determination, genetic analysis is replaced by a biological test, the pancreatitis-associated protein (PAP) enzyme-linked immunosorbent assay (ELISA). STUDY DESIGN: The French newborn screening program includes cystic fibrosis (CF) screening by the IRT/CFTR mutation strategy. PAP was assayed on screening cards, in parallel with IRT, in all newborns from 5 French regions (n = 204,749). Analysis of PAP values in CF and non-CF newborns with elevated IRT allowed direct comparison between the current strategy and the proposed IRT/PAP strategy. RESULTS: A protocol in which newborns with IRT >50 ng/mL and PAP >1.8 ng/mL and those with IRT >100 ng/mL and PAP >1.0 ng/mL are directly recalled for sweat testing would have the same performance as the IRT/CFTR mutation strategy. CONCLUSIONS: The IRT/PAP strategy is an alternative for CF newborn screening, which avoids the drawbacks of genetic analysis and is cheaper and easier to implement than the current IRT/CFTR mutation strategy.

Antigens, Neoplasm↗
PubMed1995

Neonatal screening for cystic fibrosis: a comparison of two strategies for case detection in 1.2 million babies.

OBJECTIVES: To review the overall performance of a neonatal screening program for cystic fibrosis (CF) from 1981 to 1994, and to compare two strategies of case detection. PROGRAM DESIGN: Initially, immunoreactive trypsin (IRT) was measured in dried blood spots, and because of the low sensitivity of this test at days 3 to 5, a second sample was needed from babies with positive test results. Since 1993 a positive IRT assay result has been followed by direct gene analysis for the common CF mutation, delta F508, with the use of the same sample. Cases with false-negative results were actively sought throughout the period. RESULTS: With IRT alone, 1,015,000 babies were tested. Of 389 babies with CF, 30 had a clinical diagnosis of CF made after a negative screening test result or an administrative error. Early diagnosis was achieved in 92%. With the IRT/DNA protocol, 59 of 62 infants had a positive screening test result (44 were homozygous for delta F508) among 189,000 babies tested. Three babies with CF had no copy of this mutation, but two were identified early because of meconium ileus. The false-positive rate was much greater for IRT alone than for the IRT/DNA test (0.69% vs 0.054%). All false-positive cases in the IRT/DNA protocol were, of necessity, CF carriers. CONCLUSION: The percentage of babies with CF who had an early diagnosis was similar with the two protocols, but we concluded that the advantages of the IRT/DNA test for screening, particularly in the avoidance of the need for second IRT samples, outweighed the drawback of unwanted carrier detection.

Australia↗
PubMed2001

Effect of estrogen on endothelial dysfunction in postmenopausal women with diabetes.

BACKGROUND: Treatment with estrogen causes increased release of nitric oxide and this appears to be an important mechanism involved in the cardioprotective effect of estrogen. Previous studies have clearly shown that estrogen has an acute vasodilatory effect. Recently, abnormality of flow mediated endothelial dilation, which is defined as an endothelial dysfunction, has been proposed as an early manifestation of atherogenesis. However, its effect in type 2 diabetes is unknown. Stimulus-provoked endothelium dependent dilatation, using high-resolution external vascular ultrasound, is a useful method in the measurement of endothelial function. The main advantages of this method are that it is completely non-invasive, accurate and reproducible. This classical method for the measurement of endothelial dysfunction, utilizing non-invasive, high-resolution ultrasonography, has some limitations especially in terms of reproducibility. To improve the accuracy and reproducibility of this method, measurements made for this study involved the use of an additional attachment. This device was an ultrasound probe that was attached to the arm of patient. In addition, this study evaluated not only a change in diameter in terms of flow mediated vasodilation, but also initial and peak response times during this test. The aims of this study are: (1) to evaluate the flow mediated peak vasoreactivity (FMD), the lag time from base line to initiation of vasodilation (IRT) and the peak response of endothelial dependent vasodilation in a control group and in young diabetic patients; and (2) to evaluate the effect of estrogen treatment on flow mediated vasodilation in postmenopausal women with diabetes. METHOD: Measurements were taken for flow mediated vasodilation (endothelial dependent vasodilation: FMD), endothelial independent vasodilation (EID) and lag time from base line to initial reaction of FMD. The aforementioned non-invasive method and attachment were used. Subjects for the experiment were 12 young people with diabetes (six male and six female, mean age 26.3) and 12 age-matched healthy controls (six male and six female, mean age 25.6). In addition, measurements were taken for FMD, EID and lag time in the brachial artery before and after estrogen supplementation (Premarin 0.625 mg for 7 days). Subjects for the experiment were 16 normal postmenopausal women and 18 age-matched postmenopausal women with type 2 diabetes. RESULT: There is no significant difference in BMI (body mass index), mean age, or blood pressure between the control group and the young diabetic group. There were no differences in age, total and LDL cholesterol levels or body mass index between the groups of postmenopausal women (P<0.05). However, the HDL cholesterol level was found to be significantly lower in postmenopausal women with diabetes than in normal postmenopausal women (respectively, a mean+/-SD; 38.95+/-11.96 mg/dl vs. 52.20+/-9.55 mg/dl, P<0.05). The FMD of young diabetic patients is slightly lower than that of age-matched young healthy controls (healthy control: 8.9+/-2.7%, young diabetic patients: 6.3+/-2.1%, P<0.05). There was no difference in endothelial independent vasodilation between the control group and the young diabetic group. The IRT of FMD was significantly shorter in the healthy control group than in the young diabetic group (healthy control: 20.4+/-2.8 s, diabetic group: 29.5+/-5.4 s, P<0.0001). In contrast, the IRT of EID was no different between the two groups. The IRT of FMD showed a significant negative correlation with FMD (r=-0.61, P<0.01) and a significant negative correlation with high-density lipoprotein (HDL) cholesterol (r=-0.68, P<0.0001). The basal endothelium dependent vascular reactivity was significantly decreased in postmenopausal women with diabetes compared with normal postmenopausal women (8.0+/-3.9 vs. 13.7+/-6.2%, P<0.05). Estrogen supplementation increased endothelium dependent vasodilation not only in postmenopausal women with diabetes (from 8.0+/-3.9 to 15.1+/-4.0%, P<0.05) but also in normal postmenopausal women (from 13.7+/-6.2 to 20.1+/-4.7%, P<0.05). In contrast, the responses to sublingual nitroglycerin were comparable between postmenopausal women with diabetes (from 21.1+/-6.0 to 22.1+/-4.1%, P>0.05) and normal postmenopausal women (from 25.8+/-7.8 to 25.2+/-4.5%, P>0.05), both before and after estrogen supplementation. CONCLUSION: These findings indicate that in addition to the percentage change in FMD, lag time from base line to initial response time (IRT) of FMD is a good indicator for evaluation of endothelial dysfunction. Also, this new parameter may be a more sensitive parameter for differentiation between the diseased state and the normal state of the endothelium than percentage changes in FMD. In terms of postmenopausal women, endothelial dysfunction was prominent in women with diabetes and was significantly improved by estrogen but not reversed. These results suggest that other factors in addition to estrogen deficiency play a role in endothelial dysfunction in postmenopausal women with diabetes mellitus.

Adult↗
PubMed1999

Immunoreactive trypsinogen levels in pediatric patients with intestinal failure awaiting intestinal transplantation.

The aim of this study was to evaluate pancreatic function in total parenteral nutrition (TPN)-dependent children with permanent intestinal failure by measuring immunoreactive trypsinogen (IRT) levels. Between 1992 and 1996, 105 pediatric patients with permanent intestinal failure were referred to the Children's Hospital of Pittsburgh for small intestinal transplant evaluation. Serum samples were available from 55 of them. Ten suffered from intestinal pseudo-obstruction or microvillus inclusion disease, while 45 had short bowel syndrome (SBS). IRT levels were significantly higher (p < 0.001) in SBS patients (89.4 +/- 9.2 ng mL) compared to controls (43.4 +/- 5.6 ng/ nL) without liver, gastrointestinal, or kidney disease. IRT levels did not correlate with liver injury, length of bowel, or the cause of SBS. Five of 20 patients who underwent intestinal transplantation developed pancreatitis during a median post-operative follow up 15.4 months later. IRT levels failed to predict who would develop pancreatitis post-transplant. The data suggest that elevated plasma IRT levels are common among children with intestinal failure, but fail to identify patients at risk for pancreatitis post-transplant.

Adolescent↗
PubMed1998

Adult age differences in the temporal characteristics of category free recall.

Two experiments are reported that examined the temporal structure of recall for categorizable word lists by younger and older adults. All participants showed response bursting, in which recall order is clustered by semantic category, with longer interresponse times (IRTs) appearing between categories than within categories. Experiment 1 demonstrated that older adults, even when matched to younger adults in overall accuracy, differed in the rate of increase of between-category IRTs with output position, but not in within-category IRTs. Experiment 2 showed that this interaction is eliminated when the names of the response categories are provided to the participants. Results are interpreted in terms of combined effects of an age-compromised episodic memory system (between-category IRTs) accompanied by a comparatively preserved semantic system (within-category IRTs) in healthy aging.

Adolescent↗
PubMed2003

A nonlinear mixed model framework for item response theory.

Mixed models take the dependency between observations based on the same cluster into account by introducing 1 or more random effects. Common item response theory (IRT) models introduce latent person variables to model the dependence between responses of the same participant. Assuming a distribution for the latent variables, these IRT models are formally equivalent with nonlinear mixed models. It is shown how a variety of IRT models can be formulated as particular instances of nonlinear mixed models. The unifying framework offers the advantage that relations between different IRT models become explicit and that it is rather straightforward to see how existing IRT models can be adapted and extended. The approach is illustrated with a self-report study on anger.

Anger↗
PubMed2000

[Mucoviscidosis screening of newborn infants in the Dresden district. Results from 1 June 1996 to 31 March 2000].

PROBLEM: Cystic fibrosis (CF) is the most common congenital defect of metabolism in Europe. Therefore we tried to detect this disease as early as possible before clinical symptoms occur. Thus early diagnosis can be the basis for an early start of treatment. PATIENTS AND METHODS: As part of a complete neonatal screening program in our region we investigated the concentration of immuno-reactive trypsin (IRT) in dried blood samples. Genomic investigation of the same blood sample for the most common CF mutations was performed when a critical value of IRT was exceeded. RESULTS: From 6/1996 until 3/2000 (46 months) we investigated the blood of 49,926 newborn children. Due to a high IRT value (> 70 ng/ml) in 579 cases, a genomic investigation was performed. In 38 children we detected one of the three most frequent CF mutations (delta F508, G551D, R553X) by polymerase chain reaction (PCR). The sweat test (pilocarpine iontophoresis) confirmed cystic fibrosis in 8 newborns. Four times a homocygocity for the mutation delta F508 was found and four times a compound heterocygocity (one time delta F508/R553X und three times delta F508/others). Only three of these eight CF patients already had clinical symptoms of the disease at this time, only in one case had this diagnosis been considered. An additional newborn with meconium ileus had been diagnosed as cystic fibrosis before performing the screening. Up to now we have not found any case of false negative testing. CONCLUSION: We found this procedure of neonatal testing practicable and therefore recommend its continuation. The genomic test should include the search for additional CF mutations. As alternative method a second IRT-test should be considered at the end of the first month of life for those children with initial IRT-concentrations above 150 ng/ml and without evidence of the three tested CFTR-mutations.

Cystic Fibrosis↗
PubMed2006

Validation of the NHANES ADL scale in a sample of patients with report of cervical pain: factor analysis, item response theory analysis, and line item validity.

BACKGROUND: Few functional outcomes scales have used Item Response Theory (IRT) for validation. IRT allows individual line item validations and offers substantial advantages over classic methods of scale validation or the simplest from of IRT known as Rasch. Rasch analysis reduces data to dichotomous variables thus decreasing the sensitivity of Likert-type data responses. PURPOSE: The purpose of this study was to create an outcome scale associated with the latent trait of functioning and disability, validated using IRT, in a population with report of cervical pain. METHODS: Using the NHANES database, a recently created scale (NHANES ADL scale) was analysed using factor analysis, internal analyses of consistency, IRT, and comparison with internal measures of functioning and disability. RESULTS: The newly created NHANES ADL scale demonstrated uni-dimensionality, was internally reliable, and was correlated to internal measures of functioning and disability. Additionally, the majority of the scale items demonstrate strong discrimination and suitable thresholds. DISCUSSION: The NHANES ADL scale effectively measures physical, social, and emotional disability in patients with a cervical impairment, and may be an efficient measure of perceived limitations from working and generalized daily physical activity. CONCLUSION: The newly created NHANES ADL scale demonstrates internal consistency, unidimensionality, and line item validity. The NHANES ADL scale appears to be a useful instrument in measurement of functioning and disability in patients with report of cervical pain.

Activities of Daily Living↗
PubMed1984

Immunoreactive trypsin in cystic fibrosis.

Since the first observation in 1979 that CF infants have elevated blood IRT, studies in various centres have enabled us to more fully understand the importance of this phenomenon. There is increasing evidence to show that mass newborn screening for CF using the IRT assay is practical and is capable of detecting essentially all CF newborns at a cost comparable to existing screening programs for other disorders such as Hypothyroidism. Although the elevated IRT levels seen in infancy in CF soon decrease, IRT levels in older CF patients appear to quite closely reflect the capability of that patient to secrete pancreatic enzymes and can be helpful in separating CF patients whose ability to secrete enzymes is preserved, from those with diminished exocrine pancreatic function. In all CF patients there appears to be an altered relationship between pancreatic exocrine secretion and circulating IRT levels as compared to control patients. This is probably one further manifestation of a secretory obstructive defect which although not uniformly severe, is common to all CF patients.

Adolescent↗
PubMed1989

Serum levels of immunoreactive trypsin during development: comparison with levels of lipase and amylase.

In order to obtain additional information on serum pancreatic enzyme levels during development, we have measured immunoreactive trypsin (IRT), immunoreactive lipase (IRL), and total amylase in paired fetal and maternal sera. Samples were obtained during early gestation (14-21 week of gestation) and at the time of normal delivery. IRT levels were lower in maternal sera as compared to paired fetal and neonatal (p less than 0.005); conversely, IRL and amylase, although present in measurable concentrations, were significantly lower in fetal and neonatal sera than in the maternal (p less than 0.001). We also serially monitored serum pancreatic enzyme levels in a group of premature infants during the first 10 days of life. Concentrations of IRT showed a significant increase over time (p less than 0.05) and those of IRL remained stable while amylase levels decreased sharply, suggesting possible maternal origin of this enzyme. Serum concentrations of the three pancreatic enzymes in newborns at term (second day of life) were higher than in infants aged 0.5-6 months; however, only IRT levels were above the normal range for adults. Beyond the neonatal period, IRT levels were stable and comparable to adults, whereas amylase and IRL levels were very low in infants younger than 6 months and increased significantly with age (p less than 0.001). These data seem to indicate that "physiologic hypertrypsinemia" occurs early during development and may be accentuated by postnatal events. They provide an indirect indication of both early fetal production of trypsinogen and possible placental transfer of pancreatic enzymes from the maternal circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗
PubMed2000

Item response theory and health outcomes measurement in the 21st century.

Item response theory (IRT) has a number of potential advantages over classical test theory in assessing self-reported health outcomes. IRT models yield invariant item and latent trait estimates (within a linear transformation), standard errors conditional on trait level, and trait estimates anchored to item content. IRT also facilitates evaluation of differential item functioning, inclusion of items with different response formats in the same scale, and assessment of person fit and is ideally suited for implementing computer adaptive testing. Finally, IRT methods can be helpful in developing better health outcome measures and in assessing change over time. These issues are reviewed, along with a discussion of some of the methodological and practical challenges in applying IRT methods.

Activities of Daily Living↗