Electron and recoil ion momentum imaging with a magneto-optically trapped target.

A reaction microscope (ReMi) has been combined with a magneto-optical trap (MOT) for the kinematically complete investigation of atomic break-up processes. With the novel MOTReMi apparatus, the momentum vectors of the fragments of laser-cooled and state-prepared lithium atoms are measured in coincidence and over the full solid angle. The first successful implementation of a MOTReMi could be realized due to an optimized design of the present setup, a nonstandard operation of the MOT, and by employing a switching cycle with alternating measuring and trapping periods. The very low target temperature in the MOT (∼2 mK) allows for an excellent momentum resolution. Optical preparation of the target atoms in the excited Li 2(2)P3/2 state was demonstrated providing an atomic polarization of close to 100%. While first experimental results were reported earlier, in this work, we focus on the technical description of the setup and its performance in commissioning experiments involving target ionization in 266 nm laser pulses and in collisions with projectile ions.

Ion-lithium collision dynamics studied with a laser-cooled in-ring target.

We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the 'MOTReMi,' is a combination of a magneto-optical trap (MOT) and a reaction microscope (ReMi). Operated in an ion-storage ring, the new setup enables us to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In the inaugural experiment on collisions with 1.5 MeV/amu O(8+)-Li the pure ionization of the valence electron as well as the ionization-excitation of the lithium target was investigated.

SU-E-T-474: Monte Carlo Phase Space Production to Model Magnetically Scanned Proton Beams for IMPT.

PURPOSE: Accurate dose predictions in proton beam therapy using magnetically scanned beams are highly dependent on the accurate modeling of the lateral dose profiles. This study was performed to provide proton phase spaces for Monte Carlo simulations, used to accurately simulate doses at distances up to 12 cm from the central axis of the beam. METHODS: Measured lateral dose profiles at various depths in water were compared to Monte Carlo simulations of doses for 90 discreet initial proton energies. Phase spaces were produced using a one dimensional energy distribution, and a combination of several two dimensional spatial and directional distributions. Simulations were performed iteratively using variations in the initial phase space distributions to achieve acceptable agreement between measured and simulated lateral dose profiles, i.e. differences in FWHM < 0.5 mm and dose differences less that 0.1% at distances up to 12.5 cm. RESULTS: 90 phase spaces of proton sources for different initial beam energies were created for use in Monte Carlo simulations of scanned proton beam therapy patient plans. At a depth of 2 cm in water, the simulated and measured FWHM of the lateral dose profiles differed in in-plane direction by an average of 0.05 mm, in cross-plane direction by 0.13 mm. All simulated profiles were within 0.1% of the measured doses at distances between 2cm and 12.5 cm from the central beam axis. CONCLUSIONS: A library of 90 phase space files has been created to accurately simulate magnetically scanned proton beams for IMPT, providing accurate dose distributions up to 12 cm distance from the central beam axis. This project is supported in part by P01CA021239 from the National Cancer Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.

WE-E-BRB-02: Evaluation of Analytical Proton Dose Predictions with a Lung-Like Plastic Phantom.

PURPOSE: Former studies have shown that in homogeneities in the path of therapeutic proton beams can lead to a degradation of the distal edge of the Bragg peak. These studies mostly investigated bone-air interfaces. This study focuses on distal edge degradation caused by finely structured soft tissue - air interfaces, which can be found in lung tissue. METHODS: A randomly filled voxelized lung-like phantom was designed and produced using rapid prototyping methods. The results of transmission measurements on this phantom were used to validate Monte Carlo (MC) calculations, which were then used as gold standard to calculate doses in several lung equivalent geometries (phantoms). The results were compared to the results of analytical dose calculation engines. RESULTS: Transmission measurements showed that the distal falloff width (from 90 % of the peak dose to 10 %) in water increased from 3.32 mm by 117 % to 7.19 mm for an initial proton energy of 140 MeV, and from 5.95 mm to 9.03 mm (52 %) for 200 MeV. The peak dose in the degraded beam was only 70 % (for 140 MeV) and 84 % (for 200 MeV) of the value observed in non-degraded beams. These findings were in contrast to the results obtained with analytical dose computation engines, but are in agreement with MC calculations. CONCLUSIONS: If not predicted correctly, Distal Edge Degradation in lung cancer therapy can lead to severe under-dosage of the target region and unwanted dose in organs at risk distal to the Bragg peak. Therefore clinically used dose calculation algorithms have to be extended to take lateral in homogeneities into account.

Primary cerebral toxoplasmosis: a rare case of ventriculitis and hydrocephalus in AIDS.

We describe the clinical, radiological and neuropathological findings in an adult AIDS patient presenting with ventriculitis and hydrocephalus as the primary manifestations of cerebral toxoplasmosis. Clinical symptoms including fever, headache, changes in mental status and focal neurological deficits were non-specific. Cranial computed tomography showed a subtile ventricular dilatation whereas magnetic resonance imaging disclosed triventricular hydrocephalus due to stenosis of the aqueduct and a periventricular nodular rim of high signal intensity on T2- and proton density-weighted images. This rim also showed a slight enhancement on post-contrast T1-weighted images. Focal intracerebral lesions could not be delineated, neither by neuroimaging nor by pathology. Neuropathological examination showed severe ventriculitis with large ependymal and subependymal necrosis as well as dilatation of the lateral and the third ventricle. The only microorganism demonstrated at histology in the central nervous system was Toxoplasma gondii. We conclude that ventriculitis and hydrocephalus without any focal parenchymal lesion may be the only manifestations of CNS toxoplasmosis. It is important to recognize this unusual form of presentation of cerebral toxoplasmosis in order to perform specific therapy.

Influence of maturation on the alteration of allergenicity of green pea (Pisum sativum L.).

The IgE-binding capacity of different maturation levels of green pea seeds (Pisum sativum L.) of the variety Maxigolt is examined to determine the influence of maturation on the alteration of allergenicity. Different protein extraction methods to get total protein extracts and the protein fractions glutelin, globulin, and albumin from different maturation levels of green pea seeds are applied to SDS-PAGE/silver staining as well as SDS-PAGE/immunoblotting and EAST inhibition experiments using sera of 15 green pea allergic individuals. The SDS-PAGE/silver-staining experiments show the continuous change of protein pattern during maturation. SDS-PAGE/immunoblot and EAST inhibition demonstrate that all levels of green pea seeds show relevant IgE-binding capacity, as do immature seeds. Total IgE-binding capacity rises with the progress of maturation. Although the main allergenic activity is dependent upon the albumin fraction, the glutelin and globulin fractions are also important. The implication of these results is an obvious allergenic potency of all maturation levels, even immature seeds, whereas an increase of allergenicity during maturation could be notched up. The highest allergenic potency is caused by the albumin fraction, but globulin and glutelin fractions also contribute to the allergenicity of green pea.

Chordomas: a histological and immunohistochemical study of cases with and without recurrent tumors.

Chordomas are rare, slow-growing and often recurrent neoplasms being composed of various cell types (physaliferous, epitheloid, chondroid), thus, showing a wide range of histological features. To study the relationship between histological and immunohistochemical pattern and biological behavior according to different cell types, the authors studied 33 specimens of 17 patients with and without recurrent tumors. Additionally, the histological features according to nuclear atypia and mitotic activity of both groups were analyzed and compared with each other. Predominance of one cell type was observed in 19 specimens (10 were composed mainly of physaliferous, 8 of the epitheloid and one of chondroid cell type). In 7 cases, areas of chondroid differentiation were present. MIB proliferation index tended not to be higher in recurrent tumors but in cases with nuclear atypia and nuclear pleomorphism seems to be predictive for recurrency. Immunohistochemically, nearly all cell types (physaliferous, epithelial-like and cells of chondroid differentiation) of both recurrent and non recurrent chordomas stained positive for epithel membrane antigen (EMA), cytokeratins (KL1, AE1/AE3), S100, vimentin and negative for HMB45 and desmin. Positive staining for NSE was observed in 70% of cases, however, the chondroid componente stained negative in every case.

Desynchronising effect of the endothelium on intracellular Ca2+ concentration dynamics in vascular smooth muscle cells of rat mesenteric arteries.

The kinetics of the intracellular Ca2+ concentration ([Ca2+]i) of vascular smooth muscle cells (VSMCs) in rat small mesenteric arteries was investigated by confocal laser scanning microscopy using the fluorescent Ca2+ indicator fluo-3 AM. One micromole noradrenaline (NA) induced randomly distributed transient elevations of [Ca2+]i in several single VSMCs which were weakly temporally coupled. Higher NA concentrations of 3 or 10 microM, however, induced strongly synchronised [Ca2+]i oscillations in VSMCs. In preparations with intact endothelium, the synchronisation of [Ca2+]i signals was attenuated by acetylcholine (ACh) but augmented by the NO synthase antagonist L-NAME, pointing to a desynchronising effect of the endothelium even under basal conditions. In preparations with or without intact endothelium sodium nitroprusside (SNP) as well as the gap-junction uncoupler heptanol reversibly desynchronised the [Ca2+]i transients. The effect of ACh but not that of SNP was influenced by L-NAME. Propagated intracellular [Ca2+]i waves had a velocity of 25 microm/s. The phase shift of [Ca2+]i oscillations between single VSMCs were maximally 2s and independent of the distance of up to 90 microm between individual cells. Therefore, we consider intercellular [Ca2+]i waves to be too slow to account for the synchronisation of [Ca2+]i oscillations. We conclude that the coupling of [Ca2+]i signals in vascular smooth muscle cells is not constant but highly regulated by NA and by endothelium derived NO. Oscillations of vessel contraction at high sympathetic tone may be induced by synchronisation of [Ca2+]i transients of distinct VSMCs whereas endothelium derived NO inhibits vasomotion by desynchronising [Ca2+]i transients of single VSMCs.

Episodes of pragmatic behaviors in parent-child interactions.

Pragmatic behavior, or the socially appropriate use of language, is important to parents of preschool children. In 1994 Becker noted several questions that still remain to be answered, including issues such as developmental changes in the pragmatic teaching of preschoolers and whether there are differences in the parents' goals for pragmatic teaching in private versus public interactions. The present study addressed these issues. 29 parent-child dyads were videotaped for 30 min. Transcripts were coded for episodes of pragmatic behavior that occurred in the dyadic interaction. Analysis indicated that pragmatic behaviors across the age groups largely focused on issues of what to say and how to say it. The teaching and use of pragmatic behaviors in public interactions is relatively important to parents of children between 2 1/2 and 4 years. The spontaneous use of pragmatic behaviors was the most common form of input (78% overall). Pragmatic behaviors were more often prompted with direct, as opposed to indirect, comments. Discussion focuses on a content analysis of the direct versus indirect prompts in the different age groups.

Primary nodular meningeal glioma mimicking metastatic tumor of the cerebellum with diffuse infra- and supratentorial leptomeningeal spread.

A 62-year-old man presented with acute headache, blurred and double vision, nausea, and ataxia. Magnetic resonance imaging showed an enhancing mass on the inferior aspect of the right cerebellar hemisphere as well as a thin, widespread leptomeningeal enhancement and T2-weighted hyperintense lesions in the left occipital lobe and both thalami. Lumbar puncture revealed clusters of anaplastic cells. Therefore, metastatic tumor of unknown origin was suggested. Despite whole brain irradiation and intrathecal chemotherapy the patient deteriorated gradually and died four months later. Post-mortem examination of the brain revealed a nodular, high-grade astrocytic tumor within the subarachnoid space on the lower portion of the right cerebellar hemisphere. Diffuse leptomeningeal spread was noted, but cerebellar parenchyma was not infiltrated.

Telecommuting and health care: a potential for cost reductions and productivity gains.

Health care administrators are striving to maintain positive operating margins while remaining responsive to community needs. As they look for ways to reduce costs and improve productivity, they may consider the benefits associated with telecommuting. Telecommuting refers to the work performed by organizational employees who use computers and telecommunication equipment to work at home or at remote sites one or more days a week. Benefits to the health care industry include release of valuable hospital space, reduced employee turnover, and increased productivity. The time away from the institution may provide administrators with valuable planning time, free from interruptions.

The neuropathology and epidemiology of AIDS. A Berlin experience. A review of 200 cases.

The brains of 200 patients who died with Acquired Immunodeficiency Syndrome (AIDS) from Berlin were examined retrospectively. This study was specifically intended to evaluate and document the prevalence of neuropathologic abnormalities, establishing the frequency of the various types of structural lesions, their combinations, their relative incidence, and the risk factors involved in different age groups. The data were compared and contrasted with the findings reported from other parts of the world and other German cities. It was found that the mean age of this group of patients was 41.4 years old, 75% were homosexual/bisexuals (H/B) and 18.5% were drug abusers (DA). Only 5.5% were women. Brain parenchymal changes, called in this report, HIV-related encephalopathy (HIVRE), characterized by vacuolization or spongy changes and astrocytosis in the subcortical white matter, and occasionally in gray matter, were found in 67 patients (33.5%). Drug abusers had a higher incidence of HIVRE (59.5%) compared with homosexual/bisexuals (28%). This is statistically significant (p < 0.0005). CMV encephalitis was found in 26 patients (13%) (8% of the drug abusers in contrast to 13% in the homosexual/bisexuals group). Primary central nervous system lymphoma (PCNSL) was seen in 28 patients (14%) regardless of the risk factor involved. 20 (13%) of the 150 H/B and 3 (8%) of the 37 DA had CMV encephalitis. Of the 150 H/B, 24 (16%) had PCNSL compared with only 4 of 37 (11%) of the DA. A significant incidence of opportunistic infections, both protozoal and viral was found in all groups. Cerebral toxoplasmosis occurred in 68 patients (34%). Microglial (phagocytic) nodules, probably related to CMV or cerebral Toxoplasmosis, were observed in 40 cases (20%). Diffuse microglial proliferation was noted in 104 patients (52%). Cerebral cryptococcosis was found in three patients. Progressive multifocal leukoencephalopathy was seen in 16 patients (8%). Various combinations of CNS pathological processes were found in 44 of the patients (22%). These include concomitant infections with Toxoplasma gondii and HIVRE in 13 patients; Toxoplasmosis and PCNSL in 8 patients; Toxoplasmosis with CMV and HIVRE in 4 patients; Toxoplasmosis with CMV in 2 patients; Toxoplasmosis with PCNSL and CMV in 2 patients; Toxoplasmosis with PCNSL and HIVRE in 2 patients and Toxoplasmosis with PML and HIVRE in 2 patients; Cerebral CMV with PCNSL and HIVRE in 4 patients; Cerebral CMV with HIVRE in 2 patients; PML with PCNSL in one patient; PML with HIVRE in 2 patients; and PML with PCNSL and HIVRE in one patient. Cerebrovascular lesions were found in 34 patients (17%).(ABSTRACT TRUNCATED AT 400 WORDS)

One-year follow-up of 273 infants with birth weights of 700 to 1100 grams after prophylactic treatment of respiratory distress syndrome with synthetic surfactant or air placebo. American Exosurf Neonatal Study Group I.

A single dose of synthetic surfactant was administered prophylactically to premature neonates with birth weights between 700 and 1100 gm. The effects of this treatment on neurodevelopmental, neurologic, and ophthalmologic outcomes, impairments, and general health status were examined during a follow-up evaluation at 1-year adjusted age. The study was a multicenter, parallel, randomized, double-blind comparison of 446 infants who received either air placebo (n = 222) or synthetic surfactant (n = 224). Follow-up evaluations were completed for 82% of surviving infants in both treatment groups. Neurodevelopmental outcome and growth were equivalent in the infants treated with synthetic surfactant and in the infants given air placebo. Impairments occurred in 38% of the infants treated with air placebo compared with 31% of those given synthetic surfactant; the difference was not statistically significant (relative risk 0.809, 95% confidence interval 0.585, 1.119). The incidence of asthma was significantly higher in the group of infants given air placebo (4% vs 10% for surfactant and air placebo, respectively, relative risk 0.391, 95% confidence intervals 0.157, 0.972). Other outcomes, including retinopathy of prematurity, hospital readmissions, surgery, and evidence of chronic lung disease, were not different. Administration of a single prophylactic dose of synthetic surfactant increases survival in infants with birth weights between 700 and 110 gm without increasing the number or proportion of impaired survivors.

Prospective, randomized comparison of high-frequency oscillation and conventional ventilation in candidates for extracorporeal membrane oxygenation.

OBJECTIVE: To compare the safety and efficacy of high-frequency oscillation (HFO) with conventional ventilation in the treatment of neonates with respiratory failure. DESIGN: We conducted a multicenter, prospective, randomized trial. Patients were stratified according to pulmonary diagnosis and then were randomly selected for conventional ventilation or HFO. A balanced crossover design offered patients who met criteria of treatment failure a trial of the alternative mode of ventilation. SETTING: Four tertiary, level 3 neonatal intensive care units accepting regional referrals for extracorporeal membrane oxygenation. PATIENTS: Neonates were eligible for enrollment if their gestational age was > 34 weeks, their birth weight was > or = 2 kg, they were < 14 days of age, they required fractional inspired oxygen > 0.50 and a mean airway pressure > 0.98 kPa (10 cm H2O) to support adequate oxygenation, and they required a peak inspiratory pressure > 2.9 kPa (30 cm H2O) and a rate > 40 breaths per minute to support adequate ventilation. Exclusion criteria were lethal congenital anomalies, profound shock, need for cardiopulmonary resuscitation, and failure to obtain consent. MAIN RESULTS: Of 79 patients studied, 40 were assigned to conventional ventilation and 39 to HFO. Neonates randomly assigned to HFO required higher peak pressure (3.8 +/- 0.5 vs 3.3 +/- 0.8 kPa, 39 +/- 5 vs 34 +/- 8 cm H2O; p = 0.004) and more often met extracorporeal membrane oxygenation criteria (67% vs 40%; p = 0.03) at study entry than did those given conventional ventilation. Twenty-four patients (60%) assigned to conventional ventilation met treatment failure criteria compared with 17 (44%) of those assigned to HFO (not significant). Of the 24 patients in whom conventional ventilation failed, 15 (63%) responded to HFO; 4 (23%) of the 17 in whom HFO failed responded to conventional ventilation (p = 0.03). There were no differences between the two groups with respect to outcome, need for extracorporeal membrane oxygenation, or complications. CONCLUSIONS: We conclude that HFO is a safe and effective rescue technique in the treatment of neonates with respiratory failure in whom conventional ventilation fails.

Extracerebral toxoplasmosis in AIDS. Histological and immunohistological findings based on 80 autopsy cases.

Despite the great amount of literature concerning toxoplasmic encephalitis in AIDS patients, little is known about extracerebral toxoplasmosis. Therefore we conducted a study of 80 autopsy cases to estimate the frequency of extracerebral toxoplasmosis. A control group of 50 cases was completely negative for all markers applied. In 35 of the 80 AIDS-cases (43.7%), organisms could be detected. In 13 cases (16.2%) there was an extracerebral toxoplasmosis; 4 cases (5%) showed only extracerebral involvement and in 9 cases (11.2%), extracerebral toxoplasmosis occurred in combination with cerebral manifestations. In 22 cases (27.5%), only cerebral toxoplasmosis was found. The following organs were involved: cardiac muscle (15%), lungs (6.2%), liver (5%), pancreas (5%), gastrointestinal tract (6.2%), adrenal glands (5%), lymph nodes (5%) and testis (3.7%). In individual cases further organs, not mentioned above, were involved. Pseudocysts could be demonstrated within necroses and inflammatory foci by conventional staining, whereas trophozoites became apparent only immunohistologically.

The development of children's knowledge structures: events, slots, and taxonomies.

Seventeen preschool (age range 2; 10-3;6), 26 kindergarten (age range 5;5-6;7), and 26 fourth-grade (age range 9;5-10;5) children's knowledge structures were examined with a word association task and a match-to-sample picture task to determine whether or not children used slot-filler categories as a mediating structure between event-based and taxonomic knowledge structures, as proposed by Nelson (1985, 1986). In general, preschool children were able to provide event-based, but not slot-filler or taxonomic, relations; kindergarten children were able to provide event-based or slot-filler relations, but very few taxonomic relations; and fourth-grade children were able to provide all three relations. These findings support Nelson's hypothesis that taxonomic knowledge structures are derived from event-based knowledge structures with the aid of slot-filler categories.

Controlled trial of a single dose of synthetic surfactant at birth in premature infants weighing 500 to 699 grams. The American Exosurf Neonatal Study Group I.

In a multicenter, double-blind, placebo-controlled trial conducted at 23 hospitals in the United States, a single prophylactic 5 ml/kg dose of a synthetic surfactant (Exosurf Neonatal) or air placebo was administered shortly after birth to 215 infants with birth weights of 500 to 699 gm. Despite stratification at entry by birth weight and gender, by chance female infants predominated in the air placebo group and male infants predominated in the surfactant group. Among infants receiving synthetic surfactant, improvements in oxygen requirements were significant at 2 hours after birth (p = 0.014) and persisted for 3 days (p = 0.001); improvements in the alveolar-arterial partial pressure of oxygen gradient were significant at 6 hours after birth (p = 0.01) and persisted for 3 days (p = 0.008). Improvements in mean airway pressure were not significant at 2 or at 6 hours after birth (p = 0.622 and 0.083, respectively), but became significant thereafter and persisted for 3 days (p = 0.002). Pneumothorax was reduced by slightly more than half (25 vs 11; p = 0.014); death from respiratory distress syndrome (RDS) was also reduced (26 vs 15; p = 0.046). Overall neonatal mortality, however, was not significantly reduced (58 vs 46; p = 0.102). Other complications of RDS and prematurity were not altered, except that pulmonary hemorrhage occurred significantly more frequently in infants receiving synthetic surfactant (2 vs 12; p = 0.006). These findings indicate that a single prophylactic dose of synthetic surfactant in infants weighing 500 to 699 gm at birth improves lung function, incidence of air leak, and death from RDS but not overall mortality. The only safety problem identified was an increase in pulmonary hemorrhage.

Social interactions of speech- and language-impaired children.

Social interactions among preschool children were classified into four groups according to language ability: normally developing English, specific language impairment (SLI), speech impairment (SI), and English as a second language (ESL). The children were observed in naturalistic classroom interactions on three occasions. Conversational turns were coded according to initiations and responses, and addressee. The results reveal differences across the groups of children. Normal language peers initiate interactions with each other and have a higher percentage of longer responses; normal language peers were the preferred addressee in peer initiations. In contrast, children with limited communication skills were more likely than their normal language peers to initiate with adults and to shorten their responses or use nonverbal responses. ESL children were the least likely to initiate interactions and were the most likely to be avoided as the recipient of an initiation. The findings are interpreted as evidence that preschool children are sensitive to relative communication skills and make adjustments in their social interactions accordingly. Multiple contributing factors are implicated, including intelligibility, limited linguistic flexibility, limited discourse skills, and self-consciousness about communicative competence.

[Immunohistochemical demonstration of extracerebral toxoplasmosis in AIDS]. / Immunhistologischer Nachweis der extrazerebralen Toxoplasmose bei AIDS.

Tissue slides obtained at autopsy from 80 cases with AIDS were studied immunhistochemically for infection with Toxoplasma gondii. In 35 cases (43.75%) toxoplasmosis could be found: in 22 cases (27.5%) only cerebral, in 9 cases (11.25%) cerebral and extracerebral and in 4 cases (5%) only extracerebral. Necrotizing lesions, due to the parasite could be seen in brain, heart, lungs, pancreas, adrenal glands and testis, only intracellular trophozoites without tissue damage in GIT, liver, lymphnodes, spleen, prostate, kidney and gl. parotis. The trophozoites and pseudocysts could be clearly demonstrated by immunohistochemistry.

[Acute intermittent porphyria--diagnostic difficulties and treatment]. / Ostra przerywana porfiria--trudnosci diagnostyczne i leczenie.

A patient is described in whom acute intermittent porphyria was diagnosed after 6 months of treatment and five stays in hospital during which the cause of her manifestations was not established. Treatment of the patient and principles of treatment of acute attack of intermittent porphyria are described.