Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “INDEXING”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54Linked to original sources
PubMed2002

Development and validation of a risk-adjustment index for older patients: the high-risk diagnoses for the elderly scale.

OBJECTIVES: The purpose of this study was to develop and validate a risk-adjustment index for 1-year mortality specific to older people, based on administrative discharge diagnoses. DESIGN: Two prospective cohort studies, in tandem. The index developed in the initial cohort was subsequently validated in a separate cohort. SETTING: General medicine service of a university teaching hospital. PARTICIPANTS: For the development cohort, 524 hospitalized general medical patients aged 70 and older. For the validation cohort, 852 comparable patients. MEASUREMENTS: Administrative diagnosis data were used to construct the proposed index and several other widely used indices (Deyo-adapted Charlson; Acute Physiology, Age, Chronic Health Evaluation III conditions; total number of diagnoses; All Patient Refined Diagnosis Related Groups; and Disease Staging). We used receiver operating characteristic curve analysis and Cox proportional hazards modeling to compare our proposed index with the other indices with respect to predictive accuracy and strength of association with 1-year mortality. RESULTS: The High-Risk Diagnoses for the Elderly Scale was developed using 10 high-risk medical diagnoses. Individual condition weights, based on the magnitude of 1-year mortality risk, ranged from 1 (pneumonia, diabetes mellitus with end-organ damage) to 6 (lymphoma/leukemia); possible index scores ranged from 0 to 27. Mortality rates for patients categorized into four risk groups based on the index were 9.5%, 31.8%, 46.4%, and 73.6% in the development cohort (C statistic = 0.76), and 9.9%, 24.3%, 33.6%, and 50.8% in the validation subjects (C statistic = 0.68). The new index was a stronger predictor of mortality than several widely used measures. CONCLUSION: The High-Risk Diagnoses for the Elderly Scale, based on readily available administrative data,is a simple, accurate system for prediction of 1-year mortality in older hospitalized patients that demonstrated generalizability to an independent sample. Future studies are needed to test this index in other settings and populations.

Aged↗
PubMedDate not supplied

Temporal and spatial patterns of the clinical surveillance of BSE in France, analysed from January 1991 to May 2002 through a vigilance index.

Between 1991 and mid 2000, the surveillance of Bovine Spongiform Encephalopathy (BSE) in France was based solely on clinical surveillance through a Mandatory Reporting System. Since 2000, the implementation of active surveillance programmes using rapid tests, as a complementary tool targeted at dead and slaughtered cattle has shown that part of the BSE cases were not detected with the clinical surveillance. In order to obtain a better knowledge of the strength of the clinical surveillance, we analysed a vigilance index defined as the ratio of negative clinical suspicions to the cattle population in the region and period of interest. The temporal analysis of the vigilance index showed that it did not vary much between 1991 and 1999, increased sharply since 2000, and then decreased partly in 2001. The geographical analysis of the variations of the vigilance index was performed at the department level by comparing the observed number of negative clinical suspicions per department to the expected number, computed on the basis of the national average index and standardised on the production type of the cattle - dairy versus beef suckling cattle. As assumed, the data followed a Poisson distribution. We observed a high geographical variation of the vigilance index: ten departments out of 91 presented a significantly higher vigilance index than the national one, and four a significantly lower vigilance index. The vigilance index showed that the clinical surveillance was heterogeneous during the past twelve years, both in time and geographic location, in a range of one to ten. So the apparent trend in the BSE epidemic during this period as well as the differences in the spatial incidence of BSE have to be analysed with caution.

Animals↗
PubMed2000

The relationship of 2 professional occlusal indexes with patients' perceptions of aesthetics, function, speech, and orthodontic treatment need.

The aim of this study was to determine the relationship between patients' perceptions of orthodontic treatment need and need as determined with professionally derived indexes, namely the dental aesthetic index and the index of orthodontic treatment need. This study was undertaken at orthodontic offices in San Francisco, Calif. The pretreatment study casts of 50 consecutive patients, presenting for orthodontic treatment, were objectively assessed with these indexes by 2 examiners trained and calibrated in their use. Patients were asked to complete a questionnaire consisting of 4 questions addressing appearance, function, speech, and treatment need, using either a 5-point Likert scale or a yes/no response. The professionally derived indexes showed that statistically significant correlations existed between the aesthetic component and dental health component (r = 0.46; P <.01), the aesthetic component and dental aesthetic index (r = 0.54; P <.01), and the dental health component and dental aesthetic index (r = 0.46; P <.01). Statistically significant correlations were also found for subjective assessments between biting/chewing and speech (r = 0.31; P <.05), between speech and the aesthetic component (r = -0.39; P <. 01) and the dental aesthetic index (r = 0.34; P <.05), and between the aesthetic component and appearance (r = -0.28; P <.05). Logistic regression analysis after dichotomization (treatment/no treatment need) confirmed that the aesthetic component was the only statistically significant factor (odds ratio, 0.57; 95% confidence limits 0.34 to 0.97).

Adolescent↗
PubMed2002

Prediction of cardiac risk before abdominal aortic reconstruction: comparison of a revised Goldman Cardiac Risk Index and radioisotope ejection fraction.

BACKGROUND: A revised Goldman Cardiac Risk Index has been suggested to identify patients at higher risk for cardiac complications in patients who undergo major noncardiac surgery. The aim of this study was to test the usefulness of this model in an independent series of patients who underwent abdominal aortic surgery and to compare the index with the multiple gated acquisition (MUGA) scan in the prediction of cardiac complications. METHODS: We studied 77 patients who underwent MUGA scan before elective abdominal aortic reconstruction. The revised index was calculated for each patient after recording the following five risk factors: history of ischemic heart disease, congestive heart failure, cerebrovascular disease, insulin-dependent diabetes, and creatinine level more than 2 mg/dL. Technetium-99m MUGA scan provided information about the resting left ventricular ejection fraction (LVEF) and the presence of regional wall motion abnormalities. RESULTS: Fourteen patients (18%) had cardiac complications develop. The index proved to be a satisfactory predictor of postoperative cardiac events (P =.008), and an abnormal LVEF failed to do so (P =.1). The presence of wall abnormalities, with or without an abnormal LVEF, predicted cardiac complications (P =.004 and P =.006). Patients with a higher index score showed a tendency to have a lower LVEF (Spearman rank correlation, r = -0.43; P <.001). Wall abnormalities, with or without an abnormal LVEF, were more frequent in patients with higher scores (P =.03 and P =.009). Combining the index with the LVEF or the wall abnormalities or both could further stratify the cardiac risk (P =.004, P =.0003 and P =.0006, with chi(2) test for trend). CONCLUSION: For those patients who undergo elective abdominal aortic surgery, the revised Goldman Cardiac Risk Index is a simple method of evaluating cardiac risk with minimum resource implications. MUGA scan can offer additional stratification in patients judged with the index to be at high risk.

Aged↗
PubMed2003

Validity and repeatability of a simple index derived from the short physical activity questionnaire used in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

OBJECTIVE: To assess the validity and repeatability of a simple index designed to rank participants according to their energy expenditure estimated by self-report, by comparison with objectively measured energy expenditure assessed by heart-rate monitoring with individual calibration. DESIGN: Energy expenditure was assessed over one year by four separate episodes of 4-day heart-rate monitoring, a method previously validated against whole-body calorimetry and doubly labelled water. Cardio-respiratory fitness was assessed by four repeated measures of sub-maximum oxygen uptake. At the end of the 12-month period, participants completed a physical activity questionnaire that assessed past-year activity. A simple four-level physical activity index was derived by combining occupational physical activity together with time participating in cycling and other physical exercise (such as keep fit, aerobics, swimming and jogging). SUBJECTS: One hundred and seventy-three randomly selected men and women aged 40 to 65 years. RESULTS: The repeatability of the physical activity index was high (weighted kappa=0.6, ). There were positive associations between the physical activity index from the questionnaire and the objective measures of the ratio of daytime energy expenditure to resting metabolic rate and cardio-respiratory fitness As an indirect test of validity, there was a positive association between the physical activity index and the ratio of energy intake, assessed by 7-day food diaries, to predicted basal metabolic rate. CONCLUSIONS: The summary index of physical activity derived from the questions used in the European Prospective Investigation into Cancer and Nutrition (EPIC) study suggest it is useful for ranking participants in terms of their physical activity in large epidemiological studies. The index is simple and easy to comprehend, which may make it suitable for situations that require a concise, global index of activity.

Adult↗
PubMed2006

An evaluation of the shock index in predicting ruptured ectopic pregnancy.

In order to evaluate the shock index in predicting a ruptured ectopic pregnancy in a Nigerian obstetric population, a prospective observational study of consecutive pregnant women presenting to the emergency room of the University of Nigeria Teaching Hospital, Enugu with complaints of abdominal pain and/or vaginal bleeding in the first trimester of pregnancy over a 23-month period (1 February 2003 to 31 December 2004) was carried out. A total of 152 subjects were studied. Of these, 15 (9.9%) of the women had ruptured ectopic pregnancy while the rest had other causes of bleeding in early pregnancy. The mean shock index for ruptured ectopic pregnancy was significantly different from that for threatened abortion (p < 0.001), incomplete abortion (p = 0.022) and inevitable abortion (p < 0.001) but not from that for unruptured ectopic pregnancy and septic abortion (p > 0.05 for both categories). The areas under the relative operating characteristic (ROC) curves for shock index and heart rate were statistically significant (p < 0.001 for both variables) but those under the curves for systolic blood pressure, diastolic blood pressure and mean arterial blood pressure were not statistically significant (p > 0.05 for the three variables). From the curves, the cut-offs that combined highest sensitivity with lowest false positivity (1-specificity) were 0.935 for the shock index and 99 bpm for heart rate. On univariate logistic regression, the odds ratio (OR) for predicting ruptured ectopic pregnancy was 52.9 (95% CI = 10.9 - 257.3, p < 0.001) for shock index > or =0.935 and 26.4 (95% CI = 6.8 - 102.8, p < 0.001) for heart rate > or =99/min. On multivariate logistic regression using both shock index > or =0.935 and heart rate > or =99/min, only shock index > or =0.935 was statistically significant with an OR of 4.5 (95% CI = 1.8 - 11.6, p = 0.002). We conclude that when faced with the possibility of ruptured ectopic pregnancy, shock index has a high predictive value in the Nigerian population studied and is a useful addition to the currently available diagnostic armamentarium in ruptured ectopic pregnancy.

Adolescent↗
PubMed2001

An assessment of the new "SCORE" index as a predictor of osteoporosis in women.

BACKGROUND: The study was done to determine whether the new SCORE (Simple Calculated Osteoporosis Risk Estimation) index might reduce the utilization of bone mineral density (BMD) measurement. METHODS: 989 consecutive patients who were referred by a range of physicians for BMD assessments at one of two clinics had a SCORE index constructed. Approximately 95% of the subjects were Caucasian. The index is based on only 6 factors: age, previous fractures, rheumatoid arthritis, estrogen use, weight, and race. RESULTS: All but 1 (0.1%) of those with a femoral neck BMD T-score of < -2.5 had an abnormal SCORE index. However, its specificity was relatively low, since two thirds of those individuals also with an abnormal index had a T-score of > -2.5. One percent false negatives were also seen in the lumbar spine. CONCLUSION: The SCORE index correctly predicted those individuals who did not have an osteoporotic T-score. It was of the most value in the < 60 age group. DISCUSSION: The precise role of BMD measurement in the assessment and management of individuals possibly at risk for osteoporosis remains controversial. Our results suggest that the prior use of the SCORE index by the referring physicians to screen the patients sent for BMD measurement would have allowed them to exclude over 20% of the patients referred for assessment, and therefore reduce the need and cost of BMD measurement. The proportion of individuals who had a normal SCORE index, and would have been screened out, was 43% in the under 60 year age group, but in the 65 and over age group it provided no additional information to help with, for example, the National Osteoporosis Foundation (NOF) guidelines.

Absorptiometry, Photon↗
PubMedDate not supplied

Knowledge, awareness, and use of the UV index amongst the West Australian public.

The ultraviolet (UV) index provides an opportunity to warn people about the degree of hazard that exists on a particular day and subsequently lead to the adoption of sun protective behaviors. While the UV index has been promoted in Australia for some time, little research has been conducted into the understanding and use of the index. As such, a random telephone survey of 501 adults was conducted in December 1999 to gather data into the public's understanding and use of the UV index in Perth, Australia. A high awareness of the UV index existed among the respondents, with 90% indicating they had heard of the term UV index. However, only 5% indicated they had noticed the UV index/forecast for that particular day. The results indicate that a campaign to increase awareness of the UV index by the public is not warranted, but that efforts should be focused on developing tools to communicate behavior change messages linked to the UV index levels. The research was conducted with funding from Healthway, Health Promotion Foundation of Western Australia.

Adult↗
PubMed2002

A new surgical-site infection risk index using risk factors identified by multivariate analysis for patients undergoing coronary artery bypass graft surgery.

OBJECTIVES: To develop a new, simple, and practical risk index for patients undergoing coronary artery bypass graft (CABG) surgery, to develop a preoperative risk index that is predictive of surgical-site infection (SSI), and to compare the new risk indices with the National Nosocomial Infections Surveillance (NNIS) System risk index. DESIGN: Potential risk factor and infection data were collected prospectively and analyzed by multivariate analysis. Two new risk indices were constructed and then compared with the NNIS System risk index for predictive power for SSI. SETTING: Alfred Hospital is a 350-bed, university-affiliated, tertiary-care referral center. The cardiothoracic unit performs approximately 650 CABG procedures per year. PATIENTS: All patients undergoing CABG surgery within the cardiothoracic unit at Alfred Hospital between December 1, 1996, and September 29, 2000, were included. RESULTS: Potential risk factor data were complete for 2,345 patients. There were 199 SSIs. Obesity (odds ratio [OR], 1.78; 95% confidence interval [CI95], 1.24 to 2.55), peripheral or cerebrovascular disease (OR, 1.64; CI95, 1.16 to 2.33), insulin-dependent diabetes mellitus (OR, 2.29; CI95, 1.15 to 4.54), and a procedure lasting longer than 5 hours (OR, 1.75; CI95, 1.18 to 2.58) were identified as independent risk factors for SSI. With the use of a different combination of these risk factors, two risk indices were constructed and compared using the Goodman-Kruskal nonparametric correlation coefficient (G). kisk index B had the highest G value (0.3405; CI95, 0.2245 to 0.4565), compared with the NNIS System risk index G value (0.3142; CI95, 0.1462 to 0.4822). The G value for risk index A, constructed from preoperative variables only, was 0.3299 (CI9,, 0.2039 to 0.4559). CONCLUSION: Two new risk indices have been developed. Both indices are as predictive as the NNIS System risk index. One of the new risk indices can also be applied preoperatively.

Adult↗
PubMed2005

Prognostic indexes in follicular lymphoma: a comparison of different prognostic systems.

BACKGROUND: The International Prognostic Index (IPI), initially designed for aggressive lymphomas, is also used in follicular lymphoma (FL) and other indolent lymphomas. Two new prognostic indexes have recently been proposed for FL [the Italian Lymphoma Intergroup (ILI) Index and the Follicular Lymphoma International Prognostic Index (FLIPI)]. PATIENTS AND METHODS: Three indexes, IPI [age >60 years, extranodal involvement two or more sites, elevated lactate dehydrogenase (LDH), Eastern Cooperative Oncology Group performance status > or =2, stage > or =3], ILI (age >60 years, extranodal involvement two or more sites, elevated LDH, male sex, B symptoms, erythrocyte sedimentation rate > or =30 mm first hour) and FLIPI (age >60 years, stage > or =3, elevated LDH, nodal involvement five or more, haemoglobin level < or =12 g/dl) were calculated in 411 patients with FL. RESULTS: Overall concordance between the three indexes was 54%. A total of 126 (31%) patients were included in the high-risk group according to IPI, 131 (32%) according to ILI and 157 (38%) after FLIPI application. Ten-year overall survival rates after applying the prognostic indexes (IPI, ILI and FLIPI) were, respectively: 72%, 71% and 72%, in the low-risk group; 51%, 60% and 49% in the intermediate-risk group; and 24%, 16% and 31% in the high-risk group. CONCLUSIONS: In this series, all three indexes, IPI, ILI and FLIPI, were useful to classify FL patients into differentiated risk groups, although the FLIPI identified a larger proportion of high-risk patients than the IPI and ILI.

Adult↗
PubMed1984

Use of the mental function index in older adults. Reliability, validity, and measurement of change over time.

The Mental Function Index is a weighted combination of scores on three brief tests. The Index was developed to aid in the discrimination of elderly persons with early cases of senile dementia from nondemented elderly individuals. In a previous report (Am J Epidemiol 1981;114:515-27), the authors described preliminary results with the Index in 195 elderly persons in a southern California retirement community. The present study seeks to assess whether similar results can be achieved in samples other than that from which the discriminant function defining the Index was derived. Seven separate studies were done on a total of 210 persons, comprising subjects recruited from a teaching hospital which serves a predominantly lower to lower-middle class population, referrals from the same physicians as in the earlier study, and (for the reliability sample) persons from the upper-middle class community which was the major referral source. It was found that scores on the brief measures correlate 0.86 with those on the three Halstead-Reitan subtests most sensitive to brain damage and to aging. The Index provides a graded measure of disease severity comparable to global neurologic assessment (r = -0.84) and level of social function (r = 0.76). Entry Index is a crude predictor of cognitive status in older adults after several years. Changes in the Index over time parallel those in independent measures of change. The results suggest that the Index will be useful for assessment of disease severity and of longitudinal change, as well as for diagnostic screening, in population studies of senile dementia.

Aged↗
PubMed2001

Indexation of left ventricular mass in adults with a novel approximation for fat-free mass.

BACKGROUND: Indexation to fat-free mass (FFM) seems to be the best option for adjusting left ventricular (LV) mass. However, measurements of FFM are frequently not available. OBJECTIVES: To define the relation of FFM with commonly available anthropometric measures in order to derive an approximation formula of FFM that can be used for valid indexation of LV mass. SUBJECTS AND METHODS: A total of 1,371 subjects from a community survey were examined by echocardiography to measure LV mass and by bioelectrical impedance analyses (BIA) for the determination of FFM. An approximation of FFM was generated in a healthy subgroup of 213 men and 291 women by non-linear regression techniques. RESULTS: Compared with body height, height2.0, height2.7, (the superscripts following weight and height are raised powers used as a more appropriate method for indexing LV mass) or body surface area, FFM measured by BIA in the healthy subgroups was best predicted by gender-specific equations of the form: FFM = 5.1 x height1.14 x weight0.41 for men and FFM = 5.34 x height1.47 x weight0.33 for women. In the healthy reference group, indexation of LV mass for BIA-determined FFM and approximated FFM (FFMa), respectively, equally eliminated gender differences in LV mass and markedly reduced the influence of body mass index without affecting the associations between blood pressure and LV mass. Validation of FFMa in two independent population-based samples, aged 52 to 67 years, of the same source population confirmed that LV mass indexed by FFMa produced results that were highly consistent with those obtained with indexation by BIA-determined FFM. CONCLUSIONS: We propose a novel approximation of FFM based on exponentials of body height and weight. It performed well in the indexation of LV mass in middle-aged men and women of this study. Evaluation of the equation in other populations should be awaited before its use is recommended in situations where direct determination of FFM is not possible.

Adult↗
PubMed2002

Impact of proliferation index on outcome in childhood malignant gliomas: results in a multi-institutional cohort.

OBJECTIVE: Prognoses of pediatric high-grade gliomas are unpredictable, even when clinical and histological factors are taken into account. In preliminary studies with an institutional cohort of pediatric high-grade gliomas, we observed a strong association between outcome and proliferation index, as assessed by immunolabeling with the MIB-1 antibody. To determine whether this marker could provide prognostically useful information independent of tumor histology, we examined the prognostic usefulness of this marker in the multi-institutional cohort of Children's Cancer Group Study 945, the largest group of childhood high-grade gliomas analyzed to date. METHODS: The study group consisted of tumors within this cohort that were classified as high-grade gliomas on central review according to contemporary World Health Organization guidelines and that had sufficient histopathological material to permit proliferation index assessment. Paraffin-embedded sections were cut and processed, microwave antigen enhancement was used, and MIB-1 indices were calculated by percent labeling in approximately 2000 cells (5-10 high-power fields) in the areas with greatest labeling. To ensure that the review diagnostic classification and proliferation labeling index were assigned independently for each tumor, these analyses were performed by two different neuropathologists at separate institutions, and each was blinded to the results of the other. RESULTS: Ninety-eight tumors met eligibility criteria for this study. Among these high-grade gliomas, there was a strong association between MIB-1 labeling and patient outcome: 5-year progression-free survival was 33 +/- 7% in 43 patients whose tumors had MIB-1 indices of less than 18%, 22 +/- 8% in the 27 patients whose tumors had indices between 18 and 36%, and 11 +/- 6% in the 28 patients whose tumors had indices greater than 36% (P = 0.003). As anticipated, a strong association was also observed between histology and MIB-1 labeling index in these cases. Mean labeling indices were 19.4 +/- 2.66 for tumors classified as anaplastic astrocytoma versus 32.1 +/- 3.08 for those classified as glioblastoma multiforme (P = 0.0024). Notwithstanding this correlation, a significant association was noted between labeling index and progression-free survival, even after the analysis had been stratified by histology (P = 0.001). Although histology had an independent association with outcome, the prognostic value of MIB-1 labeling transcended histological subgrouping and was apparent both in tumors classified as anaplastic astrocytoma (P = 0.02) and in those classified as glioblastoma multiforme (P = 0.046). Multivariate regression modeling confirmed the strong independent association between MIB-1 labeling index and outcome. As a group, tumors with labeling indices higher than 36% had an almost uniformly poor outcome, regardless of histology. CONCLUSION: MIB-1 labeling index and histological categorization are each prognostically relevant in childhood high-grade gliomas. MIB-1 labeling index can help to refine the accuracy of histologically based prognostic assessments.

Antigens, Nuclear↗
PubMed1995

Refractive index and osmolality of human tears.

Tear osmolality measurement, as a basic index of lacrimal physiology, is technically difficult. We investigated a simple, digital nanoliter technique of critical angle refractive index measurement. After initial comparison of the techniques with aqueous NaCl (0.5 to 1.4%), 3 successive tear samples were obtained from each of 40 normal, noncontact lens wearing subjects, aged 17 to 63 years, for analysis by nanoliter osmometry and digital refractometry. In addition, tear lactoferrin concentration was estimated with the Lactoplate immunoassay. For the range of NaCl concentrations tested, osmolality and refractive index measurements were highly correlated with concentration, and with each other. For 0.9% NaClaq the mean value of osmolality was 292.0 mOsm/kg and refractive index was 1.33419. For human tears average values were found to be: for osmolality, 303.7 +/- 22.9 mOsm/kg; for refractive index, 1.33698 +/- 0.00110; and for lactoferrin level, 1.64 +/- 0.47 mg/ml. No statistically significant correlation was obtained between either refractive index or lactoferrin level and osmolality, but refractive index and lactoferrin level were significantly correlated (r = 0.64, p < 0.001). The high correlation of refractometry and osmolality for aqueous NaCl indicates comparability of the techniques for this solution, but this does not apply to human tears. Unlike tear osmolality, tear refractive index is dependent to a greater extent upon composition, as is suggested by its correlation with lactoferrin level. Therefore, refractometry is not acceptable as a direct alternative to osmometry in the assessment of lacrimal function.

Adolescent↗
PubMed1998

Assessment of scoliosis correction in relation to flexibility using the fulcrum bending correction index.

STUDY DESIGN: A prospective study on adolescent idiopathic scoliosis to assess a new method of describing frontal plane correction. OBJECTIVE: To assess the difference between using the correction rate and using the new fulcrum bending correction index when describing scoliosis correction. SUMMARY OF BACKGROUND DATA: A description of the outcome of scoliosis surgery based on the correction rate does not take into account the curve's flexibility. METHODS: The fulcrum bending correction index is calculated by dividing the correction rate by the fulcrum flexibility (based on the fulcrum bending radiograph) and is expressed as a percentage. The fulcrum bending correction index was compared with the correction rate in 35 patients with adolescent idiopathic scoliosis undergoing surgical correction. These patients were divided into a stiff and a flexible group based on a fulcrum flexibility of 50% to show the advantage of the fulcrum bending correction index over the correction rate. RESULTS: The difference in correction rate between the flexible (66%) and the stiff group (45%) was significant (P < 0.05). The difference in the fulcrum bending correction index between the flexible (96%) and the stiff group (107%) was not significant (P = 0.2). CONCLUSIONS: The fulcrum bending correction index takes into account the curve flexibility and is therefore better than the correction rate for comparing curve correction and use of instrumentation systems between different series of patients. A fulcrum bending correction index of close to 100% suggests that the instrumentation has taken up all the flexibility revealed by the fulcrum bending radiograph. It is recommended that the fulcrum bending correction index be used in the future as part of the postoperative assessment of frontal plane correction in cases of thoracic scoliosis.

Adolescent↗
PubMed2005

Amniotic fluid index and fetal bladder outlet obstruction. Do we really need more?

PURPOSE: With the constant advances in technology and expertise of prenatal diagnosis, necessity of early counseling in cases of bilateral obstructive uropathy has become of paramount importance. To better evaluate fetal renal function new biochemical (serum and urine) fetal markers have been introduced in the literature. However, they are only available at select centers and always requiring an invasive approach. Furthermore, paucity of normal controls sometimes makes interpretation of results difficult. Owing to this growing interest towards biochemical evaluation of fetal renal function, assessment of amniotic fluid, which is mostly expression of fetal urination, has progressively fallen into disrepute, and studies comparing the amount of amniotic fluid with renal function are scant. MATERIALS AND METHODS: In a 3-year period 28 cases of bilateral obstructive uropathy were seen prenatally at the Artemisia Medical Center. All cases were initially reviewed at 17 to 20 weeks of gestation when a distended fetal bladder with thickened wall and enlarged kidneys were visualized. At the same time ultrasonographic assessment of amniotic fluid was performed by calculating the amniotic fluid index. An amniotic fluid index less than the 25th percentile was considered below average and an index less below the 5th percentile was considered oligohydramnios, whereas an index between 50th and 75th percentiles was considered normal. All cases were subsequently evaluated for renal function up to age 1 year. Impaired renal function was defined as a serum creatinine greater than 1.2 mg/dl before age 1 year. RESULTS: Of the 28 cases 18 had an index of oligohydramnios (group 1) and 10 had a normal index (group 2). No significant variations were observed in amniotic fluid index at repeated consultations throughout pregnancy. Two cases in group 1 and 1 case in group 2 were lost to followup while in the other group 1 cases intrauterine death occurred. Bilateral obstructive uropathy was confirmed in all instances after birth as valves in 18 cases and urethral atresia in 3. Of the 12 surviving group 1 cases there were 3 neonatal deaths from severe lung hypoplasia, and in the remaining 9 cases mean serum creatinine at each evaluation before age 1 year was 1.3 +/- 0.2 mg/dl. All patients in group 2 survived with a mean serum creatinine at each evaluation of 0.6 +/- 0.1 mg/dl (p <0.05). CONCLUSIONS: Despite widespread use of prenatal biochemistry, evaluation of amniotic fluid by the amniotic fluid index remains a reproducible and inexpensive method to predict renal function in cases of bilateral obstructive uropathy of any origin. It retains its validity not only in severe, but also in milder reductions. Conversely, intact amniotic fluid mostly invariably predicts normal renal function at long-term evaluation. For a better understanding of the disease such information is to be promptly conveyed to the prospective parents at each prenatal consultation.

Female↗
PubMed2004

Propagation in and scattering from a matched metamaterial having a zero index of refraction.

Planar metamaterials that exhibit a zero index of refraction have been realized experimentally by several research groups. Their existence stimulated the present investigation, which details the properties of a passive, dispersive metamaterial that is matched to free space and has an index of refraction equal to zero. Thus, unlike previous zero-index investigations, both the permittivity and permeability are zero here at a specified frequency. One-, two-, and three-dimensional source problems are treated analytically. The one- and two-dimensional source problem results are confirmed numerically with finite difference time domain (FDTD) simulations. The FDTD simulator is also used to treat the corresponding one- and two-dimensional scattering problems. It is shown that in both the source and scattering configurations the electromagnetic fields in a matched zero-index medium take on a static character in space, yet remain dynamic in time, in such a manner that the underlying physics remains associated with propagating fields. Zero phase variation at various points in the zero-index medium is demonstrated once steady-state conditions are obtained. These behaviors are used to illustrate why a zero-index metamaterial, such as a zero-index electromagnetic band-gap structured medium, significantly narrows the far-field pattern associated with an antenna located within it. They are also used to show how a matched zero-index slab could be used to transform curved wave fronts into planar ones.

Journal Article↗
PubMed2004

An efficient re-indexing algorithm for color-mapped images.

The efficiency of lossless compression algorithms for fixed-palette images (indexed images) may change if a different indexing scheme is adopted. Many lossless compression algorithms adopt a differential-predictive approach. Hence, if the spatial distribution of the indexes over the image is smooth, greater compression ratios may be obtained. Because of this, finding an indexing scheme that realizes such a smooth distribution is a relevant issue. Obtaining an optimal re-indexing scheme is suspected to be a hard problem and only approximate solutions have been provided in literature. In this paper, we restate the re-indexing problem as a graph optimization problem: an optimal re-indexing corresponds to the heaviest Hamiltonian path in a weighted graph. It follows that any algorithm which finds a good approximate solution to this graph-theoretical problem also provides a good re-indexing. We propose a simple and easy-to-implement approximation algorithm to find such a path. The proposed technique compares favorably with most of the algorithms proposed in literature, both in terms of computational complexity and of compression ratio.

Algorithms↗