Statistical speckle study to characterize scattering media: use of two complementary approaches

Speckle produced by strongly-scattering media contains information about its optical properties. Statistical speckle study allows discrimination between media and enables one to characterize any change. Two approaches of the speckle phenomenon are used in the measurement of speckle produced by monodisperse-polystyrene microspheres in solution and mixtures of them: a stochastic approach based on the fractional Brownian motion and a classical frequential approach based on speckle size measurement. In this paper, we introduce an approach that contains the multi-scale aspect of the speckle; therefore it provides more information on the medium than the speckle dimension. The obtained results show that the stochastic approach allows a better samples discrimination than the classical frequential approach.

Historical review of the genus Dermanyssus Dugès, 1834 (Acari: Mesostigmata: Dermanyssidae)

A synthetic review of the historical systematics of Dermanyssus Dugès, 1834 (Acari: Mesostigmata: Dermanyssidae) is provided. The classification at the specific level in this early genus has not really been clarified during more than a century despite its economic impact, and the history of the genus is complex and includes various stages. Moreover, Dermanyssus currently includes 23 species, whereas the last review took only 18 species into account. Changes in the species status and position in the genus Dermanyssus from 1834 until today are presented. The evolution of the generic definition is explored and compared with other genera of the group. How the discrimination between the different species evolved in the genus is also examined. Some difficulties in the specific definitions are discussed. A current diagnosis of the genus Dermanyssus is given. A table of the species included in this genus since its first description along with their respective current positions, a list of the currently included species in Dermanyssus with their hosts, and a world map presenting their geographic distribution are provided.

The aortic translocation (Nikaidoh) procedure: Midterm results superior to the Rastelli procedure

OBJECTIVE

Midterm follow-up is analyzed after the aortic translocation (Nikaidoh) procedure, an alternative to the Rastelli procedure for ventriculoarterial discordance, ventricular septal defect, and pulmonary stenosis.

METHODS

Nineteen patients underwent a Nikaidoh procedure at a median age of 3.3 years (0.9-9.3 years). The native aortic valve was translocated from the right to the left ventricular outflow tract by full (n = 6) or partial (n = 13) mobilization of the aortic root. Seven patients with partial mobilization had the right coronary artery reimplanted as a button. The conal septum was divided in 13 patients. The right ventricular outflow tract was reconstructed with either a homograft (n = 4) or a right ventricular outflow tract patch (n = 15). The median follow-up was 11.4 years (0.1-23 years), and the median age at follow-up was 17.4 years (1-30 years). Left ventricular outflow tract obstruction and aortic insufficiency were assessed by echocardiography.

RESULTS

One patient died of right coronary arterial ischemia. All remaining patients (95%) survived. The median survival was 13.6 years (longest, 23.0 years). Seven right ventricular outflow tract reoperations were required in 5 patients (6 with obstruction and 1 with pulmonary insufficiency). No reoperations have been performed on the left ventricular outflow tract or aortic valve. No patient had any left ventricular outflow tract obstruction or aortic insufficiency more than mild (mild in 9 patients, trivial in 3 patients, and absent in 6 patients).

CONCLUSIONS

Midterm actuarial survival was 95% after the Nikaidoh procedure. Reintervention for the right ventricular outflow tract is more common when valved conduits are used versus valveless reconstruction; however, the Nikaidoh procedure provides complete freedom from important aortic insufficiency and left ventricular outflow tract obstruction.

Mutation status and clinical outcome of 89 imatinib mesylate-resistant chronic myelogenous leukemia patients: a retrospective analysis from the French intergroup of CML (Fi(phi)-LMC GROUP)

The emergence of ABL point mutations is the most frequent cause for imatinib resistance in chronic myelogenous leukemia (CML) patients and can occur during any phase of the disease; however, their clinical impact remains controversial. In this study, we retrospectively analyzed the predictive impact of 94 BCR-ABL kinase domain mutations (18 T315I, 26 P-loop, 50 in other sites) found in 89 imatinib-resistant CML patients. At imatinib onset, 64% of patients (57/89) were in chronic phase (CP), 24% (21/89) in accelerated phase (AP) and 12% (11/89) in blastic phase (BP). T315I and P-loop mutations were preferentially discovered in accelerated phase of BP CML, and other types of mutations in CP (P=0.003). With a median follow-up of 39.2 months (6.3-67.2), since imatinib initiation, overall survival (OS) was significantly worse for P-loop (28.3 months) and for T315I (12.6 months), and not reached for other mutations (P=0.0004). For CP only, multivariate analysis demonstrated a worse OS for P-loop mutations (P=0.014), and a worse progression-free survival (PFS) for T315I mutations (P=0.014). Therefore, P-loop and T315I mutations selectively impair the outcome of imatinib-resistant CML patients, in contrast to other mutations, which may benefit from dose escalation of imatinib, able to improve or stabilize disease response.

Follow-up of stable chromosomal aberrations in gamma-ray irradiated non-human primates

PURPOSE

The purpose of this study was to examine a new approach to retrospective biological dosimetry, by using a long-term animal model to determine the stability of translocation frequency after in vivo irradiation. While the frequency of dicentrics is known to decrease over time, the persistence of more stable chromosomal aberrations such as translocations could be useful if their stability were definitively proved.

MATERIALS AND METHODS

Four monkeys (Macaca fascicularis) were exposed to two different doses of ionizing radiation: 2 Gy whole body irradiation for two and 4 Gy for two others. Blood samples were obtained at various times after irradiation. Both total and two-way translocations were detected by fluorescence in situ hybridization. Translocations were scored in stable cells, that is, those without dicentrics, rings or fragments. The course of translocation frequency was analysed at four time-points: one hour (H1), 2 months (M2), 10 months (M10) and 31 months (M31) after irradiation.

RESULTS

We observed two separate trends in translocation frequency: Total translocation frequency decreased slightly in animals irradiated with a dose of 2 Gy, while two-way translocation frequency was relatively stable in all irradiated animals.

CONCLUSIONS

We confirmed the long-term stability of translocations and found that it seems to depend on the type of the translocation recorded. Overall translocations were stable for up to 31 months regardless of dose, but two-way translocations were more stable than those that were non-reciprocal, especially in stable cells.

Reliability and validity of the Pediatric Intensity Level of Therapy (PILOT) scale: a measure of the use of intracranial pressure-directed therapies

OBJECTIVE

To test the reliability and validity of the Pediatric Intensity Level of Therapy (PILOT) scale, a novel measure of overall therapeutic effort directed at controlling intracranial pressure (ICP) in the setting of severe (Glasgow Coma Scale of <or= 8) pediatric traumatic brain injury (TBI).

DESIGN

Case-control study via retrospective review of medical records.

SETTING

Tertiary-care, university-based children's hospital intensive care unit.

PATIENTS

Randomly selected patients <or=18 yrs old admitted to the intensive care unit in 2002-2003 with severe TBI (cases: group 1, n = 27), mild-moderate TBI (control: group 2, n = 30), extracranial trauma (control: group 3, n = 29), or nontraumatic illnesses (control: group 4, n = 27).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A 38-point scale was developed to quantify daily ICP-directed therapeutic effort. All currently recommended therapies are represented. Demographic and physiologic data were collected on all patients. A total of 24 of 27 patients with severe TBI received ICP-directed therapy; three did not because of judgments of futility. No control patients received ICP-directed therapy. The PILOT scale score was assessed for the first 7 days posttrauma or postadmission. Interrater reliability was 0.91 (intraclass correlation coefficient) and intrarater reliability was 0.94. The highest PILOT scale scores were in patients with severe TBI (11.7 +/- 5.6 vs. 1.3 +/- 1.7 vs. 2.0 +/- 2.1 vs. 1.9 +/- 1.8 for groups 1, 2, 3 and 4, respectively [mean +/- sd]; p < .001 by analysis of variance/Bonferroni). Patients with severe TBI who received ICP-directed therapy had higher PILOT scale scores (12.6 +/- 5.3 vs. 5.0 +/- 3.0, p = .001) than those who did not. Pearson's correlation coefficients of mean PILOT scale scores with measures of injury severity, outcome, and ICP were as follows: Glasgow Coma Scales score, -0.73 (p < .001); overall Injury Severity Score, 0.37 (p < .001); Injury Severity Score (head component only), 0.53 (p < .001); 6-month Glasgow Outcome Scale, -0.26 (p = .006); ICP burden (hours per day with ICP above treatment threshold), 0.59 (p = .002); and mean ICP, 0.41 (p = .044).

CONCLUSIONS

The PILOT scale score can be obtained retrospectively and has good reliability. It can discriminate patients receiving ICP-directed therapy, even among patients with severe TBI, and correlates with measures of injury severity, outcome, and ICP in an expected way. Thus, it seems to be a valid measure of the use of ICP-directed therapy, although prospective, multiple-center validation is recommended.

Study of the tools available in biological dosimetry to estimate the dose in cases of accidental complex overexposure to ionizing radiation: the Lilo accident

PURPOSE

To compare the efficiency of different cytogenetic tools in estimating the doses received by four people involved in the Lilo accident and to monitor the dose estimate over 4.5 years.

MATERIALS AND METHODS

Several young Georgian frontier guards handled at least one of the 12 Caesium sources found in a former Russian military camp. Overexposure lasted from July 1996 to May 1997. The Institute for Radiological Protection and Nuclear Safety (IRSN) obtained blood samples taken at several intervals post-exposure from the four most highly-exposed people. Dose estimation was performed using dicentric and translocation scoring.

RESULTS

The first dose estimations performed by dicentric scoring gave whole-body doses ranging from 0.4 to 1.3 Gy. Overexposure was complex and several mathematical models were used to take this complexity into account. This could provide information concerning the circumstances of overexposure. Concerning follow-up, the yield of dicentrics decreased by about 50% in the first 4 months following the end of overexposure whereas translocations were stable over the period of analysis.

CONCLUSION

It has been useful to compare cytogenetic results with clinical results. The results presented here reveal good stability of translocations. However the first dose estimation was not attempted until 6 months after the last exposure.

Prevalence of spontaneous closure of the ductus arteriosus in neonates at a birth weight of 1000 grams or less

OBJECTIVE

Ductus arteriosus (DA) closure occurs within 96 hours in >95% of neonates >1500 g in birth weight (BW). The prevalence and postnatal age of spontaneous ductal closure in neonates < or =1000 g in BW (extremely low birth weight [ELBW] neonates) remain unclear, as does the incidence of failure to close with indomethacin. Therefore, we prospectively examined the prevalence, postnatal age, and clinical variables associated with spontaneous DA closure, occurrence of persistent patent DA, and indomethacin failure in ELBW neonates.

METHODS

Neonates delivered at Parkland Memorial Hospital from February 2001 through December 2003 were studied. Those with congenital heart defects or death <10 days postnatally were excluded. Echocardiograms were performed 48 to 72 hours postnatal and every 48 hours until 10 days postnatally.

RESULTS

We studied 122 neonates with BW of 794 +/- 118 (SD) g and estimated gestational age (EGA) of 26 +/- 2 weeks. Spontaneous permanent DA closure occurred in 42 (34%) neonates at 4.3 +/- 2 days postnatally, with 100% closure by 8 days. These neonates were more mature, less likely to have received antenatal steroids or have hyaline membrane disease (HMD; 52% vs 79%), and more likely to be growth restricted (31% vs 5%) and delivered of hypertensive women. Using regression analysis, EGA and absence of antenatal steroids and HMD predicted ductal closure. Ten (8%) neonates with early DA closure reopened and required medical/surgical closure. Eighty neonates had persistent patent DA; 7 were surgically ligated, and 5 remained asymptomatic, with 4 of 5 closing after 10 days postnatally. Sixty-eight (85%) received indomethacin at 6.2 +/- 4 days postnatally; 41% failed therapy and had no distinguishing characteristics.

CONCLUSIONS

Spontaneous permanent DA closure occurs in >34% of ELBW neonates and is predicted by variables related to maturation, for example, EGA and an absence of HMD, whereas indomethacin failure could not be predicated.

Translocation yields in peripheral blood lymphocytes from control populations

PURPOSE

To record the latest information on control levels of translocations in cultured human lymphocytes.

MATERIALS AND METHODS

Control-level data from seven European laboratories that are using fluorescence in situ hybridization (FISH) techniques for retrospective biological dosimetry have been combined in a meta-analysis. After correction for the differing probe combinations used, tests of consistency are performed. The combined data have been used to test for individual variation, systematic variation with age, gender and smoking habits.

RESULTS

There is a strong variation of translocation yield with age but no variation was detectable with gender or smoking habits. After correction for age, homogeneity tests showed that about 10% of individuals were outside the 95% confidence limits as opposed to 5% expected. From a total of 385, there is an excess of about 20 individuals most of whom have an unexpectedly high yield of translocations.

CONCLUSIONS

For retrospective biological dosimetry purposes a generic age-dependent control level can be assumed. No other lifestyle factors such as smoking appear to have a significant effect on translocation yield.

Review of translocations detected by FISH for retrospective biological dosimetry applications

Several European laboratories have combined their research efforts to arrive at a consensus view on using fluorescence in situ hybridisation (FISH) for retrospective dosimetry. The aim of this review is to report these views and to highlight some areas where further work is needed. Translocations in the stable cells should be measured only in the cells that contain the full complement of the painted material. Two-way and one-way translocations should be combined with equal weight. The control level of translocations has a strong dependence on age, which has now been measured and the system has been calibrated. In conclusion, the technique works and a lifetime dose to the bone marrow from low-linear energy transfer radiation of 0.5 Gy above normal background levels can be measured for any individual. The main application is considered to provide an independent verification of lifetime doses to individuals who might form a part of an epidemiological study.

Cytogenetic damage in lymphocytes for the purpose of dose reconstruction: a review of three recent radiation accidents

The analysis of chromosomal aberrations in peripheral blood of radiation accident victims is an established method of biological dosimetry. The dose estimate on the basis of an in vitro calibration curve is straightforward when the radiation exposure is homogeneous and the analysis not delayed. In recent years three radiation accidents occurred, where the irradiation or sampling conditions precluded a simple estimation of the dose. During the Georgian accident soldiers carried in their pockets small sources of 137Cs leading to partial and protracted body exposures. During the Tokai-mura accident, three employees involved in the process of 235U enrichment were exposed to very high doses of gamma rays and neutrons. During the Bialystok accident, five patients with breast cancer undergoing radiotherapy were exposed to a single dose of electrons which reached about 100 Gy. In the present paper the approaches chosen to estimate, by cytogenetic methods, the doses absorbed by the people involved in the accidents are described.

International intercomparison for criticality dosimetry: the case of biological dosimetry

The Institute of Radiation Protection and Nuclear Safety (IRSN) organized a biological dosimetry international intercomparison with the purpose of comparing (i) dicentrics yield produced in human lymphocytes; (ii) the gamma and neutron dose estimate according to the corresponding laboratory calibration curve. The experimental reactor SILENE was used with different configurations: bare source 4 Gy, lead shield 1 and 2 Gy and a 60Co source 2 Gy. An increasing variation of dicentric yield per cell was observed between participants when there were more damages in the samples. Doses were derived from the observed dicentric rates according to the dose-effect relationship provided by each laboratory. Differences in dicentric rate values are more important than those in the corresponding dose values. The doses obtained by the participants were found to be in agreement with the given physical dose within 20%. The evaluation of the respective gamma and neutron dose was achieved only by four laboratories, with some small variations among them.

Criticality accident dosimetry by chromosomal analysis

The technique of measuring the frequency of dicentric chromosomal aberrations in blood lymphocytes was used to estimate doses in a simulated criticality accident. The simulation consisted of three exposures; approximately 5 Gy with a bare source and 1 and 2 Gy with a lead-shielded source. Three laboratories made separate estimates of the doses. These were made by the iterative method of apportioning the observed dicentric frequencies between the gamma and neutron components, taking account of a given gamma/neutron dose ratio, and referring the separated dicentric frequencies to dose-response calibration curves. An alternative method, based on Bayesian ideas, was employed. This was developed for interpreting dicentric frequencies in situations where the gamma/neutron ratio is uncertain. Both methods gave very similar results. One laboratory produced dose estimates close to the eventual exercise reference doses and the other laboratories estimated slightly higher values. The main reason for the higher values was the calibration relationships for fission neutrons.

Results of an inner-city school-based asthma and allergy screening pilot study: a combined approach using written questionnaires and step testing

BACKGROUND

A questionnaire alone may not be an adequate screening tool for asthma.

OBJECTIVE

To determine whether an asthma questionnaire used in combination with an exercise step test is better than a questionnaire alone in screening for asthma in children and to evaluate the validity of a rhinitis questionnaire in determining atopy.

METHODS

The International Study of Asthma and Allergies in Childhood (ISAAC) asthma core questionnaire was used to screen for asthma in 307 inner-city first through third graders. All children who had scores consistent with a diagnosis of asthma underwent step testing, as did a subset of children who had negative overall scores. All children who had inconsistent asthma scores and step test results underwent methacholine challenge testing. The same 307 children underwent rhinitis screening and children who had one or more positive responses on the ISAAC rhinitis questionnaire underwent skin testing as did a subset of children who had all negative responses.

RESULTS

Three hundred of 307 asthma and rhinitis questionnaires were returned. Twenty-eight children (9%) had global asthma scores that were considered to be positive (5 or above). Twenty-four of these children underwent step testing as did 34 randomly selected children who had negative global asthma scores. Thirty-one (91%) of the 34 children who had negative global asthma scores had negative step tests. Similarly, 20 of 24 children (83%) of the children who had positive global asthma scores had negative step tests. Only 4 children who had positive global asthma scores were step test-positive or had reversible airway obstruction at baseline. Using a positive methacholine challenge as the gold standard for establishing bronchial hyperresponsiveness, the global asthma score derived from the eight-item ISAAC asthma questionnaire yielded a sensitivity of 64%, a specificity of 11%, a positive predictive value of 47%, and a negative predictive value of 20%. Comparing the six-item ISAAC rhinitis questionnaire results to the gold standard, skin test reactivity, the questionnaire yielded a sensitivity of 76%, a specificity of 21%, a positive predictive value of 56%, and a negative predictive value of 40%.

CONCLUSIONS

Step testing was not useful as a screening tool for asthma. In addition, the ISAAC asthma questionnaire may not be a good asthma screening tool for inner-city pediatric populations, especially if the form is self-administered. Investigators should first validate both the ISAAC asthma and rhinitis screening questionnaires in the particular population to be studied before widespread asthma and allergy screening efforts are initiated using these tools.

Quantitative HOX expression in chromosomally defined subsets of acute myelogenous leukemia

We used a degenerate RT-PCR screen and subsequent real-time quantitative RT-PCR assays to examine the expression of HOX and TALE-family genes in 34 cases of chromosomally defined AML for which outcome data were available. AMLs with favorable cytogenetic features were associated with low overall HOX gene expression whereas poor prognostic cases had high levels. Characteristically, multiple HOXA family members including HOXA3-HOXA10 were jointly overexpressed in conjunction with HOXB3, HOXB6, MEIS1 and PBX3. Higher levels of expression were also observed in the FAB subtype, AML-M1. Spearmann correlation coefficients indicated that the expression levels for many of these genes were highly inter-related. While we did not detect any significant correlations between HOX expression and complete response rates or age in this limited set of patients, there was a significant correlation between event-free survival and HOXA7 with a trend toward significance for HoxA9, HoxA4 and HoxA5. While patients with elevated HOX expression did worse, there were notable exceptions. Thus, although HOX overexpression and clinical resistance to chemotherapy often coincide, they are not inextricably linked. Our results indicate that quantitative HOX analysis has the potential to add new information to the management of patients with AML, especially where characteristic chromosomal alterations are lacking.