Evaluation of a Balloon Implant for Simultaneous Magnetic Nanoparticle Hyperthermia and High-Dose-Rate Brachytherapy of Brain Tumor Resection Cavities

Previous work has reported the design of a novel thermobrachytherapy (TBT) balloon implant to deliver magnetic nanoparticle (MNP) hyperthermia and high-dose-rate (HDR) brachytherapy simultaneously after brain tumor resection, thereby maximizing their synergistic effect. This paper presents an evaluation of the robustness of the balloon device, compatibility of its heat and radiation delivery components, as well as thermal and radiation dosimetry of the TBT balloon. TBT balloon devices with 1 and 3 cm diameter were evaluated when placed in an external magnetic field with a maximal strength of 8.1 kA/m at 133 kHz. The MNP solution (nanofluid) in the balloon absorbs energy, thereby generating heat, while an HDR source travels to the center of the balloon via a catheter to deliver the radiation dose. A 3D-printed human skull model was filled with brain-tissue-equivalent gel for in-phantom heating and radiation measurements around four 3 cm balloons. For the in vivo experiments, a 1 cm diameter balloon was surgically implanted in the brains of three living pigs (40-50 kg). The durability and robustness of TBT balloon implants, as well as the compatibility of their heat and radiation delivery components, were demonstrated in laboratory studies. The presence of the nanofluid, magnetic field, and heating up to 77 °C did not affect the radiation dose significantly. Thermal mapping and 2D infrared images demonstrated spherically symmetric heating in phantom as well as in brain tissue. In vivo pig experiments showed the ability to heat well-perfused brain tissue to hyperthermic levels (≥40 °C) at a 5 mm distance from the 60 °C balloon surface.

Neonatal Thrombocytopenia as a Presenting Finding in de novo Pyruvate Kinase Deficiency

Thrombocytopenia is a common laboratory abnormality encountered in critically ill neonates. The broad differential for thrombocytopenia, and its association with potentially severe neonatal pathology, often presents a diagnostic dilemma prompting extensive evaluation. Hemolysis due to red cell enzymopathies is a rare cause of neonatal thrombocytopenia that is typically brief and self-limiting. Here, we present a case of thrombocytopenia, refractory to transfusion, associated with anemia and hyperbilirubinemia in a neonate with pyruvate kinase deficiency (PKD) arising from compound heterozygous PKLR mutations. The nature of the thrombocytopenia in this patient created considerable diagnostic uncertainty, which was ultimately resolved by whole-exome sequencing. This case emphasizes that inherited red cell defects, such as PKD, are important to consider in cases of neonatal thrombocytopenia.

Beam-pointing verification using x-ray pinhole cameras on the 60-beam OMEGA laser

On the OMEGA laser system, the beam-pointing accuracy is verified by irradiating a 4 mm diameter Au-coated spherical target with ∼23 kJ of laser energy. Up to ten x-ray pinhole cameras record the x-ray emission from all 60-beam spots. A new set of algorithms has been developed to improve the accuracy of the pointing evaluation. An updated edge-finding procedure allows one to infer the center of the sphere with subpixel accuracy. A new approach was introduced to back-propagate the pixel locations on the 2D image to the 3D surface of the sphere. A fast Fourier transform-based de-noising method significantly improves the signal-to-noise of the data. Based on the beam-pointing analysis, hard-sphere calculations of the laser-drive illumination uniformity on the target surface and the decomposition of the illumination distribution into lower order modes (1-10) are evaluated.

3D Simulations Capture the Persistent Low-Mode Asymmetries Evident in Laser-Direct-Drive Implosions on OMEGA

Spherical implosions in inertial confinement fusion are inherently sensitive to perturbations that may arise from experimental constraints and errors. Control and mitigation of low-mode (long wavelength) perturbations is a key milestone to improving implosion performances. We present the first 3D radiation-hydrodynamic simulations of directly driven inertial confinement fusion implosions with an inline package for polarized crossed-beam energy transfer. Simulations match bang times, yields (separately accounting for laser-induced high modes and fuel age), hot spot flow velocities and direction, for which polarized crossed-beam energy transfer contributes to the systematic flow orientation evident in the OMEGA implosion database. Current levels of beam mispointing, imbalance, target offset, and asymmetry from polarized crossed-beam energy transfer degrade yields by more than 40%. The effectiveness of two mitigation strategies for low modes is explored.

INNV-03. DEVELOPMENT OF A NOVEL DUAL-MODALITY BALLOON IMPLANT FOR SIMULTANEOUS HIGH-DOSE-RATE BRACHYTHERAPY AND MAGNETIC NANOPARTICLE HYPERTHERMIA OF BRAIN TUMOR RESECTION CAVITIES

PURPOSE

To develop a novel thermobrachytherapy (TBT) balloon implant that delivers hyperthermia and radiation simultaneously, with three specific aims: 1) to fabricate a prototype TBT balloon device; 2) to verify compatibility of all heating and radiation delivery components and evaluate heat and radiation dosimetry in full size skull/brain phantom models; and 3) to characterize in vivo heating patterns in pig brain.

METHODS

Five 3cm diameter TBT balloons were fabricated. Each balloon has two layers: an inner layer to be filled with saline to expand the resection cavity, and an outer layer to be filled with magnetic nanoparticle (MNP) solution to absorb energy from an external magnetic field hence generate heat. The balloon shaft houses 4 ports to fill inner and outer layers, insert a high-dose-rate brachytherapy source into the balloon center, and a fiber optic sensor into the outer layer to monitor and control balloon temperature. A 3D-printed skull phantom was filled with brain tissue-equivalent gel for in-phantom measurements of heating around a TBT balloon. Optically stimulated luminescent dosimeters and Gafchromic film were used to measure radiation dose; while motorized temperature probes placed in catheters were inserted in surrounding gel for thermal mapping. For in vivo experiments, a 1cm balloon was specifically fabricated for pigs 40-50 kg.

RESULTS

The presence of MNP, magnetic field, and 43-55°C heating did not affect radiation dose significantly. Thermal mapping demonstrated spherically symmetric heating in both phantom and in vivo brain tissue, where a higher concentration of MNP and stronger magnetic field of 1.6-4.5 kA/m at 133 kHz was used to achieve temperatures of 55°C in the much smaller balloon.

CONCLUSION

Novel dual-modality balloons have been fabricated and tested successfully in the lab and in vivo, hence providing crucial information to validate thermal modeling for combined heat and radiation treatment of brain tumor resection cavities.

Optical characterization of the on-target OMEGA focal spot at high energy using the full-beam in-tank diagnostic

The full-beam in-tank (FBIT) diagnostic has been deployed to directly measure the target-plane beam fluence profile, when operated at high energy, of the OMEGA Laser System at the University of Rochester's Laboratory for Laser Energetics. This paper presents the results of early measurements taken with this diagnostic and discusses an improvement that has overcome performance limitations discovered during the initial testing. The diagnostic gives new insight into the ability of the OMEGA Laser System to provide uniform fluence profiles that are consistent across all 60 beams in the laser. The ultimate goal of the FBIT diagnostic is to allow accurate assessment of the fluence uniformity on a spherical target in 60-beam implosion experiments.

Inferred UV fluence focal-spot profiles from soft x-ray pinhole-camera measurements on OMEGA

A method was developed with laser-irradiated Au planar foils to characterize the focal spot of UV laser beams on a target at full energy from soft x-ray emission. A pinhole camera with a back-thinned charge-coupled device detector and filtration with thin Be and Al foil filters provides images of the x-ray emission at photon energies <2 keV. This method requires a careful measurement of the relationship between the applied UV fluence and the x-ray signal, which can be described by a power-law dependence. The measured exponent γ ∼ 2 provides a dynamic range of ∼25 for the inferred UV fluence. UV fluence profiles of selected beams were measured for 100-ps and 1-ns laser pulses and were compared to directly measured profiles from an UV equivalent-target-plane diagnostic. The inferred spot size and super-Gaussian order from the x-ray technique agree within several percent with the values measured with the direct UV measurements.

Power balancing the multibeam OMEGA laser

Multibeam lasers often require an output beam balance that specifies the degree of simultaneity of the laser output energy, instantaneous power, or instantaneous irradiance (power per unit area). This work describes the general problem of balancing a multibeam laser. Specific techniques used to balance the output power of the 60-beam pulsed OMEGA Laser System are discussed along with a measured reduction of beam-to-beam imbalance. In particular, the square-pulse distortion induced by a simple saturating amplifier operating with its output at some fraction of its saturation fluence is derived, and a method to exchange gain between saturated amplifiers in a single beam that have different saturation fluences to adjust balance is described.

Gene Therapy in Patients with Transfusion-Dependent β-Thalassemia

BACKGROUND

Donor availability and transplantation-related risks limit the broad use of allogeneic hematopoietic-cell transplantation in patients with transfusion-dependent β-thalassemia. After previously establishing that lentiviral transfer of a marked β-globin (β^A-T87Q) gene could substitute for long-term red-cell transfusions in a patient with β-thalassemia, we wanted to evaluate the safety and efficacy of such gene therapy in patients with transfusion-dependent β-thalassemia.

METHODS

In two phase 1-2 studies, we obtained mobilized autologous CD34+ cells from 22 patients (12 to 35 years of age) with transfusion-dependent β-thalassemia and transduced the cells ex vivo with LentiGlobin BB305 vector, which encodes adult hemoglobin (HbA) with a T87Q amino acid substitution (HbA^T87Q). The cells were then reinfused after the patients had undergone myeloablative busulfan conditioning. We subsequently monitored adverse events, vector integration, and levels of replication-competent lentivirus. Efficacy assessments included levels of total hemoglobin and HbA^T87Q, transfusion requirements, and average vector copy number.

RESULTS

At a median of 26 months (range, 15 to 42) after infusion of the gene-modified cells, all but 1 of the 13 patients who had a non-β⁰/β⁰ genotype had stopped receiving red-cell transfusions; the levels of HbA^T87Q ranged from 3.4 to 10.0 g per deciliter, and the levels of total hemoglobin ranged from 8.2 to 13.7 g per deciliter. Correction of biologic markers of dyserythropoiesis was achieved in evaluated patients with hemoglobin levels near normal ranges. In 9 patients with a β⁰/β⁰ genotype or two copies of the IVS1-110 mutation, the median annualized transfusion volume was decreased by 73%, and red-cell transfusions were discontinued in 3 patients. Treatment-related adverse events were typical of those associated with autologous stem-cell transplantation. No clonal dominance related to vector integration was observed.

CONCLUSIONS

Gene therapy with autologous CD34+ cells transduced with the BB305 vector reduced or eliminated the need for long-term red-cell transfusions in 22 patients with severe β-thalassemia without serious adverse events related to the drug product. (Funded by Bluebird Bio and others; HGB-204 and HGB-205 ClinicalTrials.gov numbers, NCT01745120 and NCT02151526 .).

The influence of enteral obestatin administration to suckling rats on intestinal contractility

This study investigated the effect of enteral administration of obestatin on the contractility of whole-thickness preparations of duodenum and middle jejunum, as well as on the morphology of the enteric nervous system (ENS). Suckling rats were assigned to 3 groups (n=12) treated with: C-saline solution; LO-obestatin (125nmol/kgb.wt); HO-obestatin (250nmol/kgb.wt). Saline solution or obestatin were administered twice daily, from the 14th to the 21st day of life. Sections were studied in an organ bath, for isometric recording in the presence of acetylocholine (ACh), atropine (ATR) and tetradotoxin (TTX). Thickness of intestinal muscularis layer, the number of interstitial cells of Cajal (ICC) were measured in the paraffin sections. The immunodetection of Muscarinic Acetylocholine Receptor 2 (M2 receptor) was performed in the intestinal segments. In both intestinal segments HO treatment decreased the amplitude of spontaneous contraction compared to that observed in the C group. In the middle jejunum, the LO treatment also decreased the amplitude. TTX and ATR had no effect on amplitude of spontaneous contraction in the jejunum of LO and HO-treated animals. Compared to the C group, duodenal sections from HO animals and middle jejunum sections from LO and HO groups displayed a lower amplitude in response to ACh and EFS evoked contraction. An increase in the thickness of the muscularis layer was observed in the duodenum of LO and HO groups whereas the number ICC did not change significantly after treatment with obestatin. Moreover, the enteral administration of obestatin did not effect significantly on the cytoplasmic expression of M2 receptor in the jejunum. Our study demonstrated that enteral administration of obestatin to suckling rats influences small intestine contractility in the segment specific manner.

A picosecond beam-timing system for the OMEGA laser

A timing system is demonstrated for the OMEGA Laser System that guarantees all 60 beams will arrive on target simultaneously with a root mean square variability of 4 ps. The system relies on placing a scattering sphere at the target position to couple the ultraviolet light from each beam into a single photodetector.

Intracranial aneurysms in sickle cell anemia: clinical and imaging findings

BACKGROUND

Cerebral aneurysm formation is one of the cerebrovascular complications of sickle cell disease.

OBJECTIVE

To report the clinical and imaging findings of intracerebral aneurysms and their treatment in pediatric and adult patients with sickle cell disease.

METHODS

Review of clinical data via chart abstraction and radiologic features at the University of Pennsylvania and Children's Hospital of Philadelphia from 2000 to 2014 and review of the literature since 1942.

RESULTS

Nineteen patients with aneurysms (2.7%) were found in 709 imaged patients, including 1.2% of imaged children and 10.8% of adults. A total of 44 aneurysms were detected (52.6% with multiple aneurysms, overall 2.3 per patient), 35 (79.5%) in the anterior circulation and 9 in the posterior circulation (20.4%). Thirty-eight unruptured aneurysms ranging in size from 2 to 6 mm and six ruptured aneurysms ranging in size from 3 to 9 mm in diameter were found. Of the patients with ruptured aneurysms, two were treated by stent-assisted coiling, two by clipping, and one patient with coiling. In the group without a rupture, one patient was treated by coil embolization and one patient with a peripheral middle cerebral artery aneurysm was treated by aneurysmectomy. Three pediatric patients with a previously normal MR angiogram demonstrated new aneurysm formation during the study.

CONCLUSIONS

Adult patients with sickle cell disease have a high prevalence of aneurysm formation. Both pediatric and adult patients with sickle cell disease tend to develop multiple aneurysms with frequent involvement of atypical locations, in both anterior and posterior circulations.

Abstract 17: Development of High Risk TCD in Sickle Cell Disease

Background: The Stroke Prevention Trial in Sickle Cell Anemia (STOP) and Optimizing Primary Stroke Prevention in Sickle Cell Anemia (STOP 2) established routine transcranial Doppler ultrasound (TCD) as standard of care. Some information on conversion from low to high risk was derived from the STOP/2 studies but information is needed from “real world” practice to improve TCD screening guidelines.

Subjects and Methods: During STOP and STOP2, 3,837 children, ages 2 to 16 y with SCD-SS or SCD-SBeta-0-thalassemia, underwent screening TCD. The POST-STOP study was designed to follow-up all children who participated in one or both of these trials. 19 of the 26 original study sites participated in POST-STOP, contributing a total of 3,541 (92%) of STOP/STOP2 subjects. Data abstractors visited the clinical sites to extract TCD, neuroimaging and neurological outcome information.

Results: Of the 3,541 subjects, follow-up data were available for 2834 (80%). The mean age at the last TCD STOP/2study was 9.5 years, the mean age at last follow-up in POST-STOP was 19.6 years and the mean duration of follow-up after exiting STOP/STOP2 was 9.2 years. STOP TCD risk stratification was used: normal < 170 cm/sec; conditional 170-199 cm/sec; abnormal >200 cm/sec. Subjects were classified by their highest risk TCD in STOP/STOP 2. The population was divided on this basis into normal (1813 --64%), conditional (478 --17%), abnormal (357-- 13%) or inadequate (186 --7%). Among the 478 with conditional TCD studies in STOP/STOP2, the mean age at last follow-up in POST-STOP was 19.2 years (range 4.9-33.1) and follow-up TCD was obtained on 252 (53%) from 11 months to 16 years after STOP/2 (median 10.4) . Forty three of these had an abnormal TCD (mean age at abnormal was 8.5 years from 3 months to 8.4 years after STOP/2 (median 1.97 years).

Conclusions:

1) We could find evidence of follow up TCD for about of half of these children indicating that more needs to be done to insure regular and consistent surveillance of these children who have some elevated risk.

2) Conversions to abnormal TCD were documented. Treatment decisions as well as stroke outcomes for all the 479 with conditional TCD will be derived from adjudication of the complete data set (in progress).

Abstract T P369: Increased Prevalence of Potential Right-to-Left Shunting in Children with Sickle Cell Anemia and Stroke

Children with sickle cell anemia (SCA; HbSS and HgbSβ 0 thalassemia) suffer stroke at a rate 220x higher than other children, but are typically less extensively investigated for modifiable risk factors. In patients without SCA, “paradoxical embolization” via intracardiac or intrapulmonary "right-to-left" shunting is a recognized stroke risk factor. Hypercoagulable states and increased right heart pressures predispose to paradoxical embolization and both occur in SCA. We hypothesized that children with SCA and overt stroke have an increased prevalence of potential right-to-left shunting compared to controls.

We performed contrasted transthoracic echocardiograms (conventional 2D, color Doppler, and 4 contrast injections with agitated saline, including 2 during Valsalva) on children (ages 2-19y) with SCA and history of overt stroke, and a control group of children with neither SCA nor stroke, at 14 institutions in the US and UK. Potential right-to-left shunting was defined as any potential shunt detected by any method, including “late bubbles” (contrast appearing in the left heart >5 cardiac cycles following injection). Echocardiograms were reviewed locally and centrally, with adjudication of conflicts.

We enrolled 153 children with SCA and stroke and 129 controls. There were no significant differences in age or gender between the groups. The prevalence of potential right-to-left shunting was significantly higher in the SCA and stroke group (43.1% vs. 20.0% in controls (p<0.001). There was no significant difference in intracardiac shunting (22.9% vs. 16.2%, p=0.157) but there was a higher proportion with intrapulmonary shunting (“late bubbles” only) in the SCA and stroke group (27.5% vs. 5.5% in controls, p<0.001).

Our findings suggest that intracardiac and intrapulmonary shunting could be an independent, potentially modifiable risk factor for stroke or stroke recurrence in children with SCA. Additional therapeutic interventions in patients at risk of stroke or stroke recurrence via paradoxical embolization, including antiplatelet agents or shunt closure, should be evaluated in children with SCA.

250 mJ, self-adaptive, diode-side-pumped Nd:YAG slab laser

A scheme of self-adaptive, closed-loop, diode-side-pumped Nd:YAG slab laser was presented. As a result of four-wave mixing of standing waves intersecting at a small angle in a closed-loop cavity, the self-adaptive process of beam cleaning leading to fundamental mode operation despite severe asymmetry of the inversion profile and thermal-optical distortion was achieved. The output beam was extracted from the cavity as the first- order diffraction beam on the dynamic gain gratings created in an active medium. The near-diffraction-limited (parameter M(2)<1.4, divergence of 1 mrad) output beam of 250 mJ energy and the optical slope efficiency of 30% at a repetition rate of up to 25 Hz in a free-running regime were demonstrated.

Increasing hydrodynamic efficiency by reducing cross-beam energy transfer in direct-drive-implosion experiments

A series of experiments to determine the optimum laser-beam radius by balancing the reduction of cross-beam energy transfer (CBET) with increased illumination nonuniformities shows that the hydrodynamic efficiency is increased by ∼35%, which leads to a factor of 2.6 increase in the neutron yield when the laser-spot size is reduced by 20%. Over this range, the absorption is measured to increase by 15%, resulting in a 17% increase in the implosion velocity and a 10% earlier bang time. When reducing the ratio of laser-spot size to a target radius below 0.8, the rms amplitudes of the nonuniformities imposed by the smaller laser spots are measured at a convergence ratio of 2.5 to exceed 8  μm and the neutron yield saturates despite increasing absorbed energy, implosion velocity, and decreasing bang time. The results agree well with hydrodynamic simulations that include both nonlocal and CBET models.

Iron chelation adherence to deferoxamine and deferasirox in thalassemia

The Thalassemia Clinical Research Network collected adherence information from 79 patients on deferoxamine and 186 on deferasirox from 2007 to 2009. Chelation adherence was defined as percent of doses administered in the last 4 weeks (patient report) out of those prescribed(chart review). Chelation history since 2002 was available for 97 patients currently on deferoxamine and 217 on deferasirox, with crude estimates of adherence from chart review. Self-reported adherence to both deferoxamine and deferasirox were quite high, with slightly higher adherence to the oral chelator (97 vs. 92%). Ninety percent of patients on deferasirox reported at least 90% adherence, compared with 75% of patients on deferoxamine. Adherence to both chelators was highest in children, followed by adolescents and older adults.Predictors of lower deferoxamine adherence were smoking in the past year, problems sticking themselves (adults only), problems wearing their pump, and fewer transfusions in the past year. Predictors of lower deferasirox adherence were bodily pain and depression. Switching chelators resulted in increased adherence, regardless of the direction of the switch, although switching from deferoxamine to deferasirox was far more common. As adherence to deferoxamine is higher than previously reported, it appears beneficial for patients to have a choice in chelators.

Relationship between chronic transfusion therapy and body composition in subjects with thalassemia

OBJECTIVE

To measure body composition in patients with thalassemia and explore its relationship to abnormal growth and bone mass.

STUDY DESIGN

We conducted a cross-sectional, multicenter study. Fat, lean, and bone mineral density (BMD) were assessed with dual-energy x-ray absorptiometry. Medical history, food frequency, and physical activity questionnaires were conducted in 257 transfused patients with thalassemia (age, 23.7+/-11 years [mean+/-SD]; 51% male) compared with 113 non-transfused patients (21.3+/-13 years; 44% male).

RESULTS

Subjects with thalassemia were leaner compared with healthy American subjects from National Health and Nutrition Examination Survey III data. Transfused subjects had a higher percentage of body fat compared with non-transfused subjects after controlling for age, sex, and ethnicity; 11.8% of non-transfused pediatric subjects were considered underweight, significantly lower than National Health and Nutrition Examination Survey data (P=.03). Hemoglobin level was positively related to lean mass (P=.008). Body fat and lean mass were positive predictors for both height and BMD z-scores after adjustment for transfusion status, age, sex, ethnicity, calcium intake, and physical activity (all P<.001).

CONCLUSION

Although most adult patients with thalassemia had healthy body composition with rare obesity, young non-transfused patients appear at risk for being underweight. Optimizing physical activity and appropriate use of transfusion therapy may improve growth and bone health in these patients who are at-risk for being underweight.

A focal-spot diagnostic for on-shot characterization of high-energy petawatt lasers

An on-shot focal-spot diagnostic for characterizing high-energy, petawatt-class laser systems is presented. Accurate measurements at full energy are demonstrated using high-resolution wavefront sensing in combination with techniques to calibrate on-shot measurements with low-power sample beams. Results are shown for full-energy activation shots of the OMEGA EP Laser System.

Relative response of patients with myelodysplastic syndromes and other transfusion-dependent anaemias to deferasirox (ICL670): a 1-yr prospective study

OBJECTIVES/METHODS

This 1-yr prospective phase II trial evaluated the efficacy of deferasirox in regularly transfused patients aged 3-81 yrs with myelodysplastic syndromes (MDS; n = 47), Diamond-Blackfan anaemia (DBA; n = 30), other rare anaemias (n = 22) or beta-thalassaemia (n = 85). Dosage was determined by baseline liver iron concentration (LIC).

RESULTS

In patients with baseline LIC > or = 7 mg Fe/g dry weight, deferasirox initiated at 20 or 30 mg/kg/d produced statistically significant decreases in LIC (P < 0.001); these decreases were greatest in MDS and least in DBA. As chelation efficiency and iron excretion did not differ significantly between disease groups, the differences in LIC changes are consistent with mean transfusional iron intake (least in MDS: 0.28 +/- 0.14 mg/kg/d; greatest in DBA: 0.4 +/- 0.11 mg/kg/d). Overall, LIC changes were dependent on dose (P < 0.001) and transfusional iron intake (P < 0.01), but not statistically different between disease groups. Changes in serum ferritin and LIC were correlated irrespective of disease group (r = 0.59), supporting the potential use of serum ferritin for monitoring deferasirox therapy. Deferasirox had a safety profile compatible with long-term use. There were no disease-specific safety/tolerability effects: the most common adverse events were gastrointestinal disturbances, skin rash and non-progressive serum creatinine increases.

CONCLUSIONS

Deferasirox is effective for reducing iron burden with a defined, clinically manageable safety profile in patients with various transfusion-dependent anaemias. There were no disease-specific adverse events. Once differences in transfusional iron intake are accounted for, dose-dependent changes in LIC or serum ferritin are similar in MDS and other disease groups.

Angle-corrected imaging transcranial doppler sonography versus imaging and nonimaging transcranial doppler sonography in children with sickle cell disease

BACKGROUND AND PURPOSE

Nonimaging transcranial Doppler sonography (TCD) and imaging TCD (TCDI) are used for determination of the risk of stroke in children with sickle cell disease (SCD). The purpose was to compare angle-corrected, uncorrected TCDI, and TCD blood flow velocities in children with SCD.

MATERIALS AND METHODS

A total of 37 children (mean age, 7.8 +/- 3.0 years) without intracranial arterial narrowing determined with MR angiography, were studied with use of TCD and TCDI at the same session. Depth of insonation and TCDI mean velocities with and without correction for the angle of insonation in the terminal internal carotid artery (ICA) and middle (MCA), anterior (ACA), and posterior (PCA) cerebral arteries were compared with TCD velocities with use of a paired t test.

RESULTS

Two arteries were not found on TCDI compared with 15 not found on TCD. Average angle of insonation in the MCA, ACA, ICA, and PCA was 31 degrees , 44 degrees , 25 degrees , and 29 degrees , respectively. TCDI and TCD mean depth of insonation for all arteries did not differ significantly; however, individual differences varied substantially. TCDI velocities were significantly lower than TCD velocities, respectively, for the right and left sides (mean +/- SD): MCA, 106 +/- 22 cm/s and 111 +/- 33 cm/s versus 130 +/- 19 cm/s and 134 +/- 26 cm/s; ICA, 90 +/- 14 cm/s and 98 +/- 27 cm/s versus 117 +/- 18 cm/s and 119 +/- 23 cm/s; ACA, 74 +/- 24 cm/s and 88 +/- 25 cm/s versus 105 +/- 23 cm/s and 105 +/- 31 cm/s; and PCA, 84 +/- 27 cm/s and 82 +/- 21 cm/s versus 95 +/- 23 cm/s and 94 +/- 20 cm/s. TCD and angle-corrected TCDI velocities were not statistically different except for higher angle-corrected TCDI values in the left ACA and right PCA.

CONCLUSION

TCD velocities are significantly higher than TCDI velocities but are not different from the angle-corrected TCDI velocities. TCDI identifies the major intracranial arteries more effectively than TCD.

Prevalence of fractures among the Thalassemia syndromes in North America

Historically, fractures are cited as a frequent problem in patients with Thalassemia prior to optimization of transfusion and chelation regimens. The aim of this study was to determine the prevalence of fractures in a contemporary sample of North American patients with Thalassemia. The North American Thalassemia Clinical Research Network (TCRN) database registry was used to gather historical data on 702 patients with common alpha and beta-Thalassemia diagnoses including Thalassemia Major (TM), Intermedia (TI), E/Beta, homozygous alpha Thalassemia (AT), Hemoglobin H disease (HbH) and HbH with Constant Spring (HbH/CS), who consented to a medical record chart review. Bone mineral density (BMD) measurements by DXA were available for review in a subgroup of patients (n = 312). The overall fracture prevalence among all Thalassemia syndromes was 12.1%, equally distributed between females (11.5%) and males (12.7%). Fractures occurred more frequently in TM (16.6%) and TI (12.2%) compared to E/Beta (7.4%) and alpha (2.3%). Prevalence increased with age (2.5% ages 0-10 years, 7.4% ages 11-19 years, 23.2% ages >20 years) and with use of sex hormone replacement therapy (SHRT) (P < 0.01). On average, BMD Z and T scores were 0.85 SD lower among patients with a history of fractures (mean Z/T score -2.78 vs. -1.93, 95% CI for the difference -0.49 to -1.22 SD, P = 0.02). Presence of other endocrinopathies (i.e. hypothyroidism, hypoparathyroidism and diabetes mellitus), anthropometric parameters, heart disease or hepatitis C were not significant independent predictors of fractures. These data indicate that fractures remain a frequent complication among the aging patients with both TM and TI beta-Thalassemia. However, the fracture prevalence has improved compared to published reports from the 1960s to 1970s. In addition, children with Thalassemia appear to have low fracture rates compared to the general population.

Epidemiology of human parvovirus B19 in children with sickle cell disease

Human parvovirus (HPV) B19 causes significant morbidity and mortality in children with sickle cell disease (SCD), but little data are published about the epidemiology of HPV B19 infection and its associated complications in this patient population. In this study, prevalence and incidence rates of HPV B19 were determined in 633 patients with SCD followed at The Children's Hospital of Philadelphia between November 1996 and December 2001. Thirty percent (30%) were HPV B19 immunoglobulin G (IgG) positive at first testing, and the 70% without evidence of past HPV B19 infection were tested annually. One hundred ten patients developed evidence of HPV B19 infection for an incidence rate of 11.3 per 100 patient years. Sixty-eight episodes of HPV B19-induced transient red cell aplasia occurred with the following clinical events: fever (89.7%), pain (61.8%), acute splenic sequestration (19.1%), and acute chest syndrome (11.8%). Pain, fever, and acute splenic sequestration were more frequent events with acute HPV B19 infections compared with acute events in uninfected patients. The results of this epidemiologic study, the largest and most comprehensive to date, justify the development of HPV B19 prevention strategies to diminish the frequent and often severe complications associated with HPV B19 infections in patients with SCD.

Auxin herbicides induce H(2)O(2) overproduction and tissue damage in cleavers (Galium aparine L.)

The phytotoxic effects of auxin herbicides, including the quinoline carboxylic acids quinmerac and quinclorac, the benzoic acid dicamba and the pyridine carboxylic acid picloram, were studied in relation to changes in phytohormonal ethylene and abscisic acid (ABA) levels and the production of H(2)O(2) in cleavers (Galium aparine). When plants were root-treated with 10 microM quinmerac, ethylene synthesis was stimulated in the shoot tissue, accompanied by increases in immunoreactive levels of ABA and its precursor xanthoxal. It has been demonstrated that auxin herbicide-stimulated ethylene triggers ABA biosynthesis. The time-course and dose-response of ABA accumulation closely correlated with reductions in stomatal aperture and CO(2) assimilation and increased levels of hydrogen peroxide (H(2)O(2)), deoxyribonuclease (DNase) activity and chlorophyll loss. The latter parameters were used as sensitive indicators for the progression of tissue damage. On a shoot dry weight basis, DNase activity and H(2)O(2) levels increased up to 3-fold, relative to the control. Corresponding effects were obtained using auxin herbicides from the other chemical classes or when ABA was applied exogenously. It is hypothesized, that auxin herbicides stimulate H(2)O(2) generation which contributes to the induction of cell death in Galium leaves. This overproduction of H(2)O(2) could be triggered by the decline of photosynthetic activity, due to ABA-mediated stomatal closure.

High-level expression of angiogenic factors is associated with advanced tumor stage in human neuroblastomas

Angiogenesis is essential for tumor growth and metastasis and depends on the production of angiogenic factors by tumor cells. Neuroblastoma (NB) is a common pediatric tumor of neural crest origin, which is biologically and clinically heterogeneous. Increased tumor vascular index correlates with poor outcome of NB. To determine which angiogenic factors contribute to NB angiogenesis and thereby support tumor progression, we examined the expression of eight angiogenic factors [vascular endothelial growth factor (VEGF), VEGF-B, VEGF-C, basic fibroblast growth factor, angiopoietin (Ang)-1, Ang-2, transforming growth factor alpha, and platelet-derived growth factor (PDGF)] by semiquantitative RT-PCR in 37 NB primary tumors and in 22 NB cell lines. We also analyzed the relationship between angiogenic factor expression and clinicopathological factors as well as patient survival. All eight angiogenic factors examined were expressed at various levels in NB cell lines and tumors, suggesting their involvement in NB angiogenesis. The expression levels of most angiogenic factors were correlated with each other, suggesting their synergy in regulating the angiogenic process. Significantly higher expression levels of VEGF, VEGF-B, VEGF-C, basic fibroblast growth factor, Ang-2, transforming growth factor alpha, and PDGF-A (P < 0.0001-0.026) were found in advanced-stage tumors (stages 3 and 4) compared with low-stage tumors (stages 1, 2, and 4S). Expression of PDGF-A was significantly associated with patient survival (P = 0.04). The redundancy in angiogenic factor expression suggests that inhibition of VEGF bioactivity alone might not be a sufficient approach for antiangiogenic therapy of human NB.

Risk for speech disorder associated with early recurrent otitis media with effusion: two retrospective studies

The goals of this two-part series on children with histories of early recurrent otitis media with effusion (OME) were to assess the risk for speech disorder with and without hearing loss and to develop a preliminary descriptive-explanatory model for the findings. Recently available speech analysis programs, lifespan reference data, and statistical techniques were implemented with three cohorts of children with OME and their controls originally assessed in the 1980s: 35 typically developing 3-year-old children followed since infancy in a university-affiliated pediatrics clinic, 50 typically developing children of Native American background followed since infancy in a tribal health clinic, and (in the second paper) 70 children followed prospectively from 2 months of age to 3 years of age and older. Dependent variables included information from a suite of 10 metrics of speech production (Shriberg, Austin, Lewis, McSweeny, & Wilson, 1997a, 1 997b). Constraints on available sociodemographic and hearing status information limit generalizations from the comparative findings for each database, particularly data from the two retrospective studies. The present paper reports findings from risk analysis of conversational speech data from the first two cohorts, each of which included retrospective study of children for whom data on hearing loss were not available. Early recurrent OME was not associated with increased risk for speech disorder in the pediatrics sample but was associated with approximately 4.6 (CI = 1.10-20.20) increased risk for subclinical or clinical speech disorder in the children of Native American background. Discussion underscores the appropriateness of multifactorial risk models for this subtype of child speech disorder.

Perioperative brachytherapy as an additional therapeutic option in patients with renal cell carcinoma (RCC), either inoperable or after completed percutaneous radiotherapy

Between January 1992 and December 1997 60 patients with different tumors were treated with perioperative high dose rate brachytherapy with Iridium 192 in afterloading technique (HDR), total dosis 20-30 Gy. Three of the patients had RCC. These patients are presented in detail. In elected patients in whom other forms of treatment are not available or have failed, the method offers an additional therapeutic option and can achieve excellent results.

Bronchoscopic aspects of renal cell carcinoma (RCC)

A symposium on RCC in July 1998 in Tübingen was where we to reviewed our patients with endobronchial metastatic RCC treated by bronchoscopy since 1981. 24 of 26 consecutive cases are the subject of the present study. Tumor history, X-ray findings, endobronchial appearance, treatment and the pathogenetic mechanisms of this special form of metastatic spread are demonstrated and discussed. In 5 patients > 10 years relapsed between nephrectomy and bronchoscopic tumor therapy. A thrombuslike tumor growth and bleeding were striking bronchoscopic features. In X-ray besides atelectasis, hilar or mediastinal masses were seen half of the patients, in 50% without parenchymal lung nodes, suggesting lymphogenic spread. In several patients bronchial recanalisation could be successfully repeated over long periods. Abnormal X-ray, haemoptysis or dyspnoa in patients with RCC demands bronchoscopy. In case of bronchial tumor obstruction bronchoscopic treatment offers excellent palliation.

Developmental apraxia of speech: II. Toward a diagnostic marker

This second paper in a series on developmental apraxia of speech (DAS) (Shriberg, Aram, & Kwiatkowski, 1997a) reports findings from two studies. Study I compares speech and prosody-voice profiles of a group of 14 children with suspected DAS to profiles of 73 children with speech delay (SD). Results suggest that the only linguistic domain that differentiates some children with suspected DAS from those with SD is inappropriate stress. Study II cross-validates these findings, using retrospective data from a sample of 20 children with suspected DAS evaluated in a university phonology clinic over a 10-year period. Discussion considers methodological and conceptual issues in the measurement of linguistic stress. Theoretical issues and implications for research and clinical practice are deferred for synthesis of the present findings with those from a multi-site cross-validation project (Shriberg, Aram, & Kwiatkowski, 1997b).

Developmental apraxia of speech: I. Descriptive and theoretical perspectives

Developmental apraxia of speech (DAS) is a putative diagnostic category for children whose speech errors presumedly (a) differ from the errors of children with developmental speech delay (SD) and (b) resemble the errors of adults with acquired apraxia of speech. The studies reported in this series (Shriberg, Aram, & Kwiatkowski, 1997a, 1997b) concern both premises, with primary focus on the first--that children with DAS can be differentiated from children with SD on the basis of one or more reliable differences in their speech error profiles. Immediate goals are to identify a diagnostic marker for DAS and to consider implications for research and clinical practice. A long-term goal is to identify the phenotype marker for DAS, on the assumption that it may be a genetically transmitted disorder. This first paper reviews relevant descriptive and theoretical perspectives. Findings from a local ascertainment study support the clinical functionality of the term suspected DAS.

Developmental apraxia of speech: III. A subtype marked by inappropriate stress

Two prior studies in this series (Shriberg, Aram, & Kwiatkowski, 1997a, 1997b) address the premise that children with developmental apraxia of speech (DAS) can be differentiated from children with speech delay (SD) on the basis of one or more reliable differences in their speech. The first study compared segmental and prosody-voice profiles of a group of 14 children with suspected DAS to profiles of 73 children with SD. Results suggest that the only linguistic domain that differentiates some children with suspected DAS from those with SD is inappropriate stress. The second study cross-validated these findings, using retrospective data from a sample of 20 children with suspected DAS evaluated in a university phonology clinic over a 10-year period. The present study is of particular interest because it cross-validates the prior stress findings, using conversational speech samples from 19 children with suspected DAS provided by five DAS researchers at geographically diverse diagnostic facilities in North America. Summed across the three studies, 52% of 48 eligible samples from 53 children with suspected DAS had inappropriate stress, compared to 10% of 71 eligible samples from 73 age-matched children with speech delay of unknown origin. Discussion first focuses on the implications of stress findings for theories of the origin and nature of DAS. Perspectives in psycholinguistics, neurolinguistics, and developmental biolinguistics lead to five working hypotheses pending validation in ongoing studies: (a) inappropriate stress is a diagnostic marker for at least one subtype of DAS, (b) the psycholinguistic loci of inappropriate stress in this subtype of DAS are in phonological representational processes, (c) the proximal origin of this subtype of DAS is a neurogenically specific deficit, (d) the distal origin of this form of DAS is an inherited genetic polymorphism, and (e) significant differences between acquired apraxia of speech in adults and findings for this subtype of DAS call into question the inference that it is an apractic, motor speech disorder. Concluding discussion considers implications of these findings for research in DAS and for clinical practice.

Developmental phonological disorders. II. Short-term speech-sound normalization

A companion paper (Shriberg & Kwiatkowski, 1994) provides a descriptive profile of three samples of children (n = 178) with developmental phonological disorders. The present paper describes a conceptual framework for short-term and long-term speech-sound normalization research and reports 1-year normalization outcomes for 54 of the children described in the companion paper. Although certain individual speech variables were significantly associated with normalization, there were no speech, prosody-voice, or risk-factor variables that discriminated children who achieved short-term speech-sound normalization in 1 year. Findings are discussed in relation to a two-factor framework to study and predict speech-sound normalization in developmental phonological disorders (Kwiatkowski & Shriberg, 1993; Shriberg, Kwiatkowski, & Gruber, 1992).

Developmental phonological disorders. I: A clinical profile

Detailed information on the speech, language, prosody, and voice characteristics of children with developmental phonological disorders is central to diverse research questions. The present study provides a clinical profile of 178 children with developmental phonological disorders. It includes information from prior reports (Shriberg & Kwiatkowski, 1982a; Shriberg, Kwiatkowski, Best, Hengst, & Terselic-Weber, 1986) and from several new measures on a sample of 64 children. The speech, prosody-voice, and causal-correlates profiles for the most recent sample are consistent with prior findings, providing a descriptive profile for forthcoming subgroup research and companion studies addressing short-term (Shriberg, Kwiatkowski, & Gruber, 1994) and long-term (Shriberg, Gruber, & Kwiatkowski, 1994) speech-sound normalization.

Developmental phonological disorders. III: Long-term speech-sound normalization

Prior articles in this series provide a descriptive profile of 178 children with developmental phonological disorders (Shriberg & Kwiatkowski, 1994) and predictive correlates of short-term speech-sound normalization in 54 children (Shriberg, Kwiatkowski, & Gruber, 1994). The present article reports findings from a study of 10 children with developmental phonological disorders whose progress was followed at least once yearly for 7 years. Analyses characterize the sequence, rates, and error patterns of long-term speech-sound normalization in relation to developmental perspectives on the nature of children's phonological disorders. Findings are interpreted to support the hypothesis of a critical period for speech-sound development, with long-term normalization of significant speech delay reaching a chronological age boundary at approximately 8.5 years.

Tabletop versus microcomputer-assisted speech management: response evocation phase

This is the third in a series of studies on the use of microcomputers with speech-delayed children. Two repeated-measures designs (n = 15) and five case studies were completed to compare tabletop management at early and late stages of the response development phase with two comparable, computer-assisted drill-and-practice activities. Discrimination of correct articulatory responses was mediated by the clinician in all modes, rather than by speech recognition hardware, but all contingent reinforcement in the computer modes was presented by animation graphics. The two computer modes were identical except for the addition of fantasy involvement in one of the modes. Findings indicated that the three modes of intervention were equally effective, efficient, and engaging. Subject-level analyses suggested that microcomputer software has excellent potential to engage children in drill-and-practice for late-phase response evocation, when the target sound is stimulable, but limited usefulness with young children at early-phase response evocation, when specific articulatory behaviors need to be cued. Discussion considers learning, child, and hardware/software factors in microcomputer-assisted speech management.

Tabletop versus microcomputer-assisted speech management: stabilization phase

Few controlled data are available on the efficacy of microcomputers for speech management with children. The focus of this second report in a study series using microcomputers with speech-delayed children (Shriberg, Kwiatkowski, & Snyder, 1986) is on the response stabilization stage of speech management. Two repeated-measures designs were conducted with two samples of preschool children (n = 18) to compare tabletop management with comparable computer-assisted activities. Findings indicate that response stabilization tasks in the two intervention modes were equally effective, efficient, and engaging. Additional analyses suggest that the two modes engage the children in different ways, however, and that children may have individual needs for mode-specific features.

A follow-up study of children with phonologic disorders of unknown origin

Recent emphasis on early intervention programming for children with speech delays of unknown origin has yielded considerable literature on alternative forms of assessment and management. Less is known about the long-term special educational needs of such children. This study reviews the exceptional educational needs histories of 36 children who had received preschool speech services at a phonology clinic. Findings indicate that a high percentage of children continued to have speech and language and other special educational needs as they neared middle school and beyond. Many children eventually required special class placements. Discussion focuses on issues in classification, prediction, and management. On the bases of both original and follow-up data in this and other studies, the term phonological disorder appears to be appropriate for approximately 75%-80% of children referred early for speech disorders of unknown origin.

Regulation of plant morphology by growth retardants: effects on phytohormone levels in soybean seedlings determined by immunoassay

The effects of the growth retardants tetcyclacis, a norbornenodiazetine, and LAB 150 978, a dioxanylalkenyl triazole, on seedling growth and endogenous levels of phytohormone-like substances in Glycine max L. cv Maple Arrow were studied. The levels of phytohormone-like substances in the root and in the various shoot tissues were analyzed by immunoassay. After seed treatment with both compounds, shoot growth was reduced more intensively than root growth. Both compounds decreased, on a fresh weight basis, the amount of various immunoreactive gibberellins when compared with the levels in control plants, especially in the shoot tip. Likewise, the growth retardants lowered the levels of abscisic acid-like material, particularly in the primary leaf, the epicotyl and the root. In contrast, the levels of trans-zeatin-riboside and dihydrozeatin-riboside-type cytokinins were considerably elevated by the growth retardants, mainly in the primary leaf, epicotyl, and hypocotyl. On the other hand the level of isopentenyladenosine-like material was less influenced. In general, the immunoreactive 3-indoleacetic acid content in the different plant parts was changed only slightly. It is assumed that besides their effect on gibberellin content both compounds interfere directly or indirectly with the regulation of the endogenous levels of abscisic acid and cytokinins. This might be seen as an additional mode of action of growth retardants explaining some side effects on developmental processes of treated plants, e.g. delayed senescence and enhanced chlorophyll concentration in the leaves.

Articulation testing by microcomputer

The picture naming articulation test, one of the most widely used speech assessment procedures, provides an excellent paradigm to study the potential of microcomputers with young, speech involved children. The stimulus-response format of the articulation test is structurally similar to assessment and management procedures crossing the spectrum of speech disorders. Findings from three studies comparing booklet-presented pictures to microcomputer-presented graphics indicate that microcomputers have certain control advantages in motivating children's repeated trials. However, spontaneous articulation testing by microcomputer may take more time than booklet testing if the graphics are less readily identifiable and due to associated novelty effects. Discussion of findings includes suggestions for enhancing the client-clinician-computer interface as this discipline experiences the entry of microcomputers into the speech-language clinic.

Characteristics of children with phonologic disorders of unknown origin

Descriptive data are presented from three studies of children referred for assessment of a developmental speech disorder of unknown origin. Group findings indicate that these children have involvements in mechanism, cognitive, and psychosocial areas that warrant attention in theoretical explication of and early intervention for their communication deficits. The reliability, learnability, and efficiency of a diagnostic classification system that attempts to provide characteristic speech profiles for diagnostic subtypes is also considered.

Continuous speech sampling for phonologic analyses of speech-delayed children

Five conditions for sampling the continuous speech of speech-delayed children were defined and compared. Conditions differed on variables associated with examiner behavior and stimulus materials. All sampling conditions were administered in randomized order by two examiners who each tested 6 children. The obtained speech samples were compared for productivity, intelligibility, representativeness, and reactivity. The general findings of few significant differences associated with sampling conditions support the validity of continuous speech sampling for phonologic analyses of speech-delayed children. Protocols for the five conditions are provided, and guidelines for efficient speech sampling are suggested.