The Lucy Thermal Emission Spectrometer (L'TES) Instrument

The Lucy Thermal Emission Spectrometer (L'TES) will provide remote measurements of the thermophysical properties of the Trojan asteroids studied by the Lucy mission. L'TES is build-to-print hardware copy of the OTES instrument flown on OSIRIS-REx. It is a Fourier Transform spectrometer covering the spectral range 5.71-100 μm (1750-100 cm-1) with spectral sampling intervals of 8.64, 17.3, and 34.6 cm-1 and a 7.3-mrad field of view. The L'TES telescope is a 15.2-cm diameter Cassegrain telescope that feeds a flat-plate Michelson moving mirror mounted on a linear voice-coil motor assembly to a single uncooled deuterated l-alanine doped triglycine sulfate (DLATGS) pyroelectric detector. A significant firmware change from OTES is the ability to acquire interferograms of different length and spectral resolution with acquisition times of 0.5, 1, and 2 seconds. A single ∼0.851 μm laser diode is used in a metrology interferometer to provide precise moving mirror control and IR sampling at 772 Hz. The beamsplitter is a 38-mm diameter, 1-mm thick chemical vapor deposited diamond with an antireflection microstructure to minimize surface reflection. An internal calibration cone blackbody target, together with observations of space, provides radiometric calibration. The radiometric precision in a single spectrum is ≤2.2 × 10-8 W cm-2 sr-1 /cm-1 between 300 and 1350 cm-1. The absolute temperature error is <2 K for scene temperatures >75 K. The overall L'TES envelope size is 37.6 × 29.0 × 30.4 cm, and the mass is 6.47 kg. The power consumption is 12.6 W average. L'TES was developed by Arizona State University with AZ Space Technologies developing the electronics. L'TES was integrated, tested, and radiometrically calibrated on the Arizona State University campus in Tempe, AZ. Initial data from space have verified the instrument's radiometric and spatial performance.

Nonalcoholic steatohepatitis diagnosis and treatment from the perspective of patients and primary care physicians: a cross-sectional survey

BACKGROUND

The global prevalence of nonalcoholic steatohepatitis (NASH) is rising. Despite this, NASH is underdiagnosed and does not yet have approved pharmacological treatments. We sought to understand the path to diagnosis, patient interactions with healthcare professionals, treatment regimens, and disease management for patients with NASH.

METHODS

Cross-sectional online surveys of patients with a self-reported diagnosis of NASH and healthcare professionals treating patients with NASH were conducted from 10^th November 2020, to 1st January 2021. This manuscript focuses on responses from 152 patients with NASH and 101 primary care physicians (PCPs).

RESULTS

Patients (n = 152, mean age = 40, SD = 11) and healthcare professionals (n = 226) were located throughout the US. In the most common patient journey, 72% of patients had initial discussions about symptoms with a PCP but only 30% report receiving their NASH diagnosis from a PCP. Almost half of PCPs (47%) were not aware of any clinical practice guidelines for diagnosis and management of NASH. For ongoing management of NASH, PCPs most frequently prescribed lifestyle changes such as exercise (89%), lifestyle changes focused on diet (79%), and/or metformin (57%). Other healthcare professionals rarely referred patients to PCPs for treatment, but when they did, the primary reasons were patients struggling with lifestyle modifications (58%), needing to lose weight (46%), and needing treatment of comorbidities (42%).

CONCLUSIONS

PCPs may benefit from greater awareness of NASH and guidelines for its diagnosis and treatment. Given the absence of pharmacological treatments approved for NASH, PCPs can offer support in obesity management, comorbidity management, and risk stratification for liver disease progression.

Nonalcoholic steatohepatitis medical patient journey from the perspective of hepatologists, gastroenterologists and patients: a cross-sectional survey

Background

Nonalcoholic steatohepatitis (NASH), the inflammatory subtype of nonalcoholic fatty liver disease, is underdiagnosed and expected to become the leading indication for liver transplant in the United States. We aimed to understand the medical journey of patients with NASH and role of hepatologists/gastroenterologists in diagnosing and treating patients with NASH.

Methods

A United States population-based cross-sectional online survey was completed by 226 healthcare professionals (HCPs) who treat patients with NASH and 152 patients with NASH; this study focuses on the patient and 75 hepatologist/gastroenterologist HCP respondents. Tests of differences (chi square, t-tests) between respondent types were performed using SPSS.

Results

Most patients reported receiving their diagnosis of NASH from a hepatologist (37%) or gastroenterologist (26%). Hepatologists/gastroenterologists were more likely than other HCPs to use FibroScan (transient elastography) to diagnose NASH and were more likely to distinguish between NASH with or without fibrosis. Hepatologists/gastroenterologists (68%) and patients (52%) agree that hepatologists/gastroenterologists are the primary coordinators of NASH care. The majority of hepatologists/gastroenterologists (85%) are aware of American Association for the Study of Liver Diseases (AASLD) clinical practice guidance, and 86% of those aware consider them when diagnosing patients with NASH. Hepatologists/gastroenterologists most frequently recommended exercise (86%), diet (70%), and supplements (58%) for ongoing management of NASH. Pharmaceutical medications for comorbidities were prescribed by a minority of hepatologists/gastroenterologists for their patients with NASH. Hepatologists/gastroenterologists cite difficulty (67%) or unwillingness (64%) to adhere to lifestyle changes as primary reasons patients with NASH discontinue NASH treatment.

Conclusions

Hepatologists/gastroenterologists are considered the coordinators of NASH care. While recognizing that patient adherence to lifestyle changes is the basis for successful treatment, important barriers limit successful implementation.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

A review of the benefits and limitations of a primary care-embedded psychiatric consultation service in a medically underserved setting

A significant percentage of patients with psychiatric disorders are exclusively seen for health-care services by primary care physicians. To address the mental health needs of such patients, collaborative models of care were developed including the embedded psychiatry consult model which places a consultant psychiatrist on-site to assist the primary care physician to recognize psychiatric disorders, prescribe psychiatric medication, and develop management strategies. Outcome studies have produced ambiguous and inconsistent findings regarding the impact of this model. This review examines a primary care-embedded psychiatric consultation service in place for nine years in a family medicine residency program. Psychiatric consultants, family physicians, and residents actively involved in the service participated in structured interviews designed to identify the clinical and educational value of the service. The benefits and limitations identified were then categorized into physician, consultant, patient, and systems factors. Among the challenges identified were inconsistent patient appointment-keeping, ambiguity about appropriate referrals, consultant scope-of-practice parameters, and delayed follow-up with consultation recommendations. Improved psychiatric education for primary care physicians also appeared to shift referrals toward more complex patients. The benefits identified included the availability of psychiatric services to underserved and disenfranchised patients, increased primary care physician comfort with medication management, and improved interprofessional communication and education. The integration of the service into the clinic fostered the development of a more psychologically minded practice. While highly valued by respondents, potential benefits of the service were limited by residency-specific factors including consultant availability and the high ratio of primary care physicians to consultants.

In vitro and in vivo efficacy of non-psychoactive cannabidiol in neuroblastoma

BACKGROUND

Neuroblastoma (nbl) is one of the most common solid cancers in children. Prognosis in advanced nbl is still poor despite aggressive multimodality therapy. Furthermore, survivors experience severe long-term multi-organ sequelae. Hence, the identification of new therapeutic strategies is of utmost importance. Cannabinoids and their derivatives have been used for years in folk medicine and later in the field of palliative care. Recently, they were found to show pharmacologic activity in cancer, including cytostatic, apoptotic, and antiangiogenic effects.

METHODS

We investigated, in vitro and in vivo, the anti-nbl effect of the most active compounds in Cannabis, Δ(9)-tetrahydrocannabinol (thc) and cannabidiol (cbd). We set out to experimentally determine the effects of those compounds on viability, invasiveness, cell cycle distribution, and programmed cell death in human nbl SK-N-SH cells.

RESULTS

Both compounds have antitumourigenic activity in vitro and impeded the growth of tumour xenografts in vivo. Of the two cannabinoids tested, cbd was the more active. Treatment with cbd reduced the viability and invasiveness of treated tumour cells in vitro and induced apoptosis (as demonstrated by morphology changes, sub-G1 cell accumulation, and annexin V assay). Moreover, cbd elicited an increase in activated caspase 3 in treated cells and tumour xenografts.

CONCLUSIONS

Our results demonstrate the antitumourigenic action of cbd on nbl cells. Because cbd is a nonpsychoactive cannabinoid that appears to be devoid of side effects, our results support its exploitation as an effective anticancer drug in the management of nbl.

Towards Extreme-Scale Simulations for Low Mach Fluids with Second-Generation Trilinos

Trilinos is an object-oriented software framework for the solution of large-scale, complex multi-physics engineering and scientific problems. While Trilinos was originally designed for scalable solutions of large problems, the fidelity needed by many simulations is significantly greater than what one could have envisioned two decades ago. When problem sizes exceed a billion elements even scalable applications and solver stacks require a complete revision. The second-generation Trilinos employs C++ templates in order to solve arbitrarily large problems. We present a case study of the integration of Trilinos with a low Mach fluids engineering application (SIERRA low Mach module/Nalu). Through the use of improved algorithms and better software engineering practices, we demonstrate good weak scaling for up to a nine billion element large eddy simulation (LES) problem on unstructured meshes with a 27 billion row matrix on 524,288 cores of an IBM Blue Gene/Q platform.

Comprehensive analysis suggests simple processes underlying EEG/ERP - demonstration with the go/no-go paradigm in ADHD

BACKGROUND

Current basic or more advanced methods for analysis of averaged EEG/ERP are based on assumptions on the underlying processes, which are not necessarily precise.

NEW METHOD

In this work we present the findings of a method which obviates such assumptions and aims at a comprehensive analysis of the averaged EEG/ERP signal.

RESULTS

For the sake of demonstration we chose the established go/no-go paradigm in the context of ADHD. Our analysis method characterized two spatiotemporally distinct neurophysiologic processes which underlie the sampled signal: one which may be related to attention and the other which may be more related to perception.

COMPARISON WITH EXISTING METHOD(S)

We show how these processes accord with and provide insight on the waveforms reported in the literature.

CONCLUSIONS

Finally we suggest that application of our method on averaged EEG/ERP data sampled from other paradigms may point at a similarly parsimonious set of underlying neurophysiologic processes which underlie the signal.

Characterization of recovery and neuropsychological consequences of orbitofrontal lesion: A case study

We present a case study of a patient with acquired prefrontal lesion involving mainly ventromedial and orbital structures (VM-PFD). The patient showed behavioral and emotional disturbances one year after the injury. In a follow-up examination seven years later, we evaluated her performance in tasks found theoretically to be sensitive to orbital and medial lesions. In contrast to our hypothesis, her performance was in the normal range. We suggest that a possible explanation for her magnificent recovery may include a high cognitive reserve and the specific characteristics of her injury.

Cavopulmonary assist for the univentricular Fontan circulation: von Kármán viscous impeller pump

OBJECTIVE

In a univentricular Fontan circulation, modest augmentation of existing cavopulmonary pressure head (2-5 mm Hg) would reduce systemic venous pressure, increase ventricular filling, and thus substantially improve circulatory status. An ideal means of providing mechanical cavopulmonary support does not exist. We hypothesized that a viscous impeller pump, based on the von Kármán viscous pump principle, is optimal for this role.

METHODS

A 3-dimensional computational model of the total cavopulmonary connection was created. The impeller was represented as a smooth 2-sided conical actuator disk with rotation in the vena caval axis. Flow was modeled under 3 conditions: (1) passive flow with no disc; (2) passive flow with a nonrotating disk, and (3) induced flow with disc rotation (0-5K rpm). Flow patterns and hydraulic performance were examined for each case. Hydraulic performance for a vaned impeller was assessed by measuring pressure increase and induced flow over 0 to 7K rpm in a laboratory mock loop.

RESULTS

A nonrotating actuator disc stabilized cavopulmonary flow, reducing power loss by 88%. Disk rotation (from baseline dynamic flow of 4.4 L/min) resulted in a pressure increase of 0.03 mm Hg. A further increase in pressure of 5 to 20 mm Hg and 0 to 5 L/min flow was obtained with a vaned impeller at 0 to 7K rpm in a laboratory mock loop.

CONCLUSIONS

A single viscous impeller pump stabilizes and augments cavopulmonary flow in 4 directions, in the desired pressure range, without venous pathway obstruction. A viscous impeller pump applies to the existing staged protocol as a temporary bridge-to-recovery or -transplant in established univentricular Fontan circulations and may enable compressed palliation of single ventricle without the need for intermediary surgical staging or use of a systemic-to-pulmonary arterial shunt.

Elimination of muscle afferent boutons from the cuneate nucleus of the rat medulla during development

There is developmental refinement of the proprioreceptive muscle afferent input to the rat ventral horn. This study explored the extent to which this occurs in the medulla. Muscle afferents were transganglionically labeled from the extensor digitorum communis forelimb muscle with cholera toxin B subunit. Tracer amounts and transport times were adjusted for animal size. Immunohistochemistry revealed tracer localization in the medulla and dorsal root ganglia. Labeled muscle afferent boutons were counted in the cuneate nucleus between postnatal days 7 and 42, during which time a large decrease in the density of labeled boutons was observed qualitatively. Localization of input to dorsolateral parts of the nucleus remained broadly the same at different ages, although disappearance of a marked innervation of ventromedial regions in more caudal sections was observed. Bouton counts were corrected for growth of the medulla with age, and any spread of tracer to adjacent muscles indicated by counts of labeled dorsal root ganglion neurons. There was a statistically significant, approximately 40% reduction in the number of muscle afferent boutons in the cuneate nucleus during this developmental period. Previous studies suggest that perturbations to the corticospinal input during a developmental critical period influence the eventual size of the muscle afferent input to the ventral horn. Corticocuneate fibers invade the nucleus during the same period and may influence reorganization of its muscle afferent input, making it another potential site for aberrant reflex development in cerebral palsy.

Bosutinib (SKI-606) exhibits clinical activity in patients with Philadelphia chromosome positive CML or ALL who failed imatinib

7006

Background: Bosutinib (SKI-606) is an orally available, dual Src/Abl kinase inhibitor. To assess safety and preliminary clinical activity of bosutinib, we conducted a phase 1/2 study in patients (pts) with Philadelphia chromosome positive (Ph+) chronic myelogenous leukemia (CML) or acute lymphocytic leukemia (ALL) who were imatinib resistant/intolerant. Methods: In part 1, 18 pts with imatinib- relapsed/refractory chronic phase (CP) CML received bosutinib 400 mg/day (3 pts), 500 mg/day (3 pts), or 600 mg/day (12 pts). Part 2 was an expanded cohort of 51 pts with all phases of Ph+ CML and ALL dosed at 500 mg daily. Timed blood samples were collected on days 1–3, 15 for PK analysis. Results: Of 69 pts, median age was 59 yrs; 48 were CP; 90% imatinib resistant. Drug-related grade 1/2 adverse events (AEs) occurring in =10% of CP pts: diarrhea (69%), nausea (44%), vomiting (19%), abdominal pain (13%), rash (13%). Grade 3/4 AEs occurring in =5% of CP pts: rash (6%), thrombocytopenia (6%). 17 pts required dose reductions. In evaluable imatinib-resistant CP-CML pts with no prior exposure to other Abl inhibitors, 16/19 (84%) had complete hematologic response (CHR); 4/21 had partial and 7/21 had complete cytogenetic responses for major cytogenetic response (MCyR) rate of 52%. Of 58 pts evaluable for mutations, 13 different imatinib-resistant mutations were found in 32 pts. 12/14 CP pts with non-P-loop mutations and 3/3 with P-loop mutations achieved CHR. 5/11 CP pts with non-P- loop mutations and 1/1 with P-loop mutation achieved MCyR. 4/9 evaluable advanced leukemia pts had CHR, 2 had MCyR. After oral administration, steady state exposure of bosutinib was nearly 2-fold higher than single-dose exposure. Mean elimination half-life was approximately 22–27 hours, supporting a once-daily dosing regimen. Conclusions: Bosutinib was well tolerated in pts with CML, with primarily low-grade gastrointestinal and dermatologic AEs. Bosutinib showed clinical activity in imatinib-resistant pts with cytogenetic responses and CHR across a range of mutations. Durability of response continues to be assessed.

[Table: see text]

Laparoscopic hepatic artery catheterization for regional chemotherapy

BACKGROUND

Metastatic disease isolated to the liver is present at the time of diagnosis in 20-30% of patients with colorectal cancer. Only 10% of patients are eligible for resection. Systemic chemotherapy remains the primary treatment modality for such patients. The morbidity associated with regional chemotherapy is largely a result of the laparotomy required to place a hepatic arterial infusion pump in these debilitated patients. We discuss the main advantages of laparoscopic approach in comparison to both open procedure and percutaneous hepatic artery catheterization.

MATERIAL AND METHODS

From November 1993 to April 2004, 27 patients (16 males, 11 females) underwent laparoscopic placement of a hepatic artery catheter. The mean age was 64.9 years (46 to 82 years). 24 patients (88.8%) had bilobar disease precluding surgical resection of the liver metastases. There were four cases of non-colon cancers, all with liver metastases.

RESULTS

LHAC alone averaged 45-55 minutes. Mean blood loss of 151 cc (20-300 cc). Postoperatively, 16 patients (59.2%) had hepatic intra-arterial chemotherapy in the recovery room as a preplanned protocol. Average hospital stay was 8.4 days (3-25 days). Median follow-up period of 8.1 months. 22 patients with residual hepatic disease, in whom chemotherapy was successfully instituted, showed regression of their metastases, in 18 patients, CEA had improved at their one-month follow-up visit. Three complications: one catheter thrombosis, one partial catheter occlusion and one eroded catheter into the duodenum one year after.

CONCLUSIONS

In experienced hands, laparoscopic hepatic artery catheterization is a safe, feasible and minimally invasive technique for those patients with metachronous liver malignancies.

Investigating the specificity of real-time PCR assays using synthetic oligonucleotides

Potato spindle tuber viroid (PSTVd) causes damaging diseases of solanaceous crops and is a quarantine pathogen in the European Union. Previously a one-tube real-time RT-PCR assay based on TaqMan chemistry was developed and shown to be ideally suited to PSTVd detection. However, since it was impossible to trace infected plant material for every published PSTVd sequence reported, in silico predictions were made about assay specificity based on the positions of nucleotide polymorphisms within the published viroid sequences and the regions of the primers and probe. The predictions could not be verified due to the absence of viroid material. This paper describes work investigating the detection of these sequence variants by designing synthetic oligonucleotides to sequences from the database and testing them with a real-time PCR assay. The results show that all PSTVd sequence variants are detected, and that the closely related Mexican papita viroid is also detected, although with a lower efficiency. The paper gives indications as to what effect nucleotide changes at different positions within primers and probes might do and should aid in the testing of future assays, although it is difficult to draw fixed rules about the possible effect changes may have.

Relationship between Changes in Thymic Emigrants and Cell-Associated HIV-1 Dna in HIV-1-Infected Children Initiating Antiretroviral Therapy

Objectives and methods

To investigate the relationship between cell-associated HIV-1 dynamics and recent thymic T-cell emigrants, HIV-1 DNA and T-cell receptor rearrangement excision circles (TREC, a marker of recent thymic emigrants) were measured in peripheral blood mononuclear cells in 181 samples from 33 HIV-1-infected children followed for 96 weeks after antiretroviral therapy (ART) initiation.

Results

At baseline, HIV-1 DNA was higher in children with higher TREC ( P=0.02) and was not related to age, CD4 or HIV-1 RNA in multivariate analyses ( P>0.3). Overall, TREC increased and HIV-1 DNA decreased significantly after ART initiation, with faster HIV-1 DNA declines in children with higher baseline TREC ( P=0.009). The greatest decreases in HIV-1 DNA occurred in children with the smallest increases in TREC levels during ART ( P=0.002). However, this inverse relationship between changes in HIV-1 DNA and TREC tended to vary according to the phase of HIV-1 RNA decline ( P=0.13); for the same increase in TREC, HIV-1 DNA decline was much smaller during persistent or transient viraemia compared with stable HIV-1 RNA suppression.

Conclusions

Overall, these findings indicate that TREC levels predict HIV-1 DNA response to ART and suggest that immune repopulation by thymic emigrants adversely affects HIV-1 DNA decline in the absence of persistent viral suppression, possibly by providing a cellular source for viral infection and replication.

Preliminary analyses of Hebrew verbal fluency measures

Hebrew language versions of phonemic and semantic fluency were administered to samples of normal control participants and individuals who had been hospitalized for 24 hr following a head injury. For the control sample, verbal fluency tasks were normally distributed and significantly correlated with education. The head injury sample's word generation was significantly lesser than that of the control's and not at all related to educational attainment. The findings provide evidence for the use of Hebrew fluency measures for clinical assessment and the need for collection of normative data across education levels.

Hodgkin's disease with an intrasinusoidal pattern of infiltration. A report of two cases

The histological distinction between Hodgkin's disease (HD) and anaplastic large cell lymphoma (ALCL) may be difficult but is important as the two conditions have different clinical behaviours, prognoses and responses to therapy. Morphological appearances that have been emphasised as favouring the diagnosis of ALCL rather than HD include the identification of neoplastic cells permeating sinusoidal spaces. We document two cases of Hodgkin's disease with classical morphological and immunohistochemical features of nodular-sclerosis subtype (HDNS) but with striking sinusoidal involvement by neoplastic cells. In each case, the CD30 positive/CD15 positive immunophenotype of the neoplastic cells was characteristic of HD without expression of any of the other antigens normally associated with ALCL. HD is generally considered to be a morphological diagnosis and, in those laboratories in which it is not possible to use wide panels of antibodies for the confirmation of the diagnosis, the identification of sinusoidal infiltration by the neoplastic cells in HD may lead to the mistaken impression of ALCL.

Effect of short-term exposure to chlorpyrifos on developmental parameters and biochemical biomarkers in Chironomus riparius Meigen

Chironomus riparius Meigen were exposed to sediment spiked with 0, 0.01, 0.05, and 0.10 mg chlorpyrifos/kg dry sediment for 48 h as late third-instar larvae. Acetylcholinesterase activity, glutathione-S-transferase activity, burrowing behavior, emergence time, and adult dry weight were measured to determine which were the most sensitive biomarkers of exposure and effect for short-term sublethal exposures. There was a significant drop in acetylcholinesterase activity at the two highest concentrations, but no effect on glutathione-S-transferase activity. Behavioral and life history biomarkers were sensitive only to the highest concentration of chlorpyrifos. The association of life history changes (female weight and male emergence times) with a significant inhibition of acetylcholinesterase activity suggests that this can be used as a biomarker of exposure and effect.

Variability in acetylcholinesterase and glutathione S-transferase activities in Chironomus riparius Meigen deployed in situ at uncontaminated field sites

An in situ system was used to expose fourth instar Chironomus riparius Meigen larvae for 48-h at 13 uncontaminated river sites across southeast England. Acetylcholinesterase (AChE) and glutathione S-transferase (GST) activities were measured in individual larvae recovered from these sites. Activities of both biomarkers varied almost twofold across the sites, with statistically significant differences detectable between sites. There were no clear relationships between biomarker activities and physical or chemical characteristics measured at each site. This study shows that biomarker measurements can be used successfully in conjunction with an in situ system. However, the results of statistically significant biomarker results must be treated with caution because natural variability in responses can occur even in the absence of toxicant exposure.

Creating interpretation guidelines for the Hebrew trail making test

The Hebrew language version of the Trail Making Test (TMT; Army Individual Test Battery, 1944) was administered to a group of normal control participants as well as a sample of outpatients approximately 1 year following a head injury. A ratio of TMT-B to TMT-A performance was computed in an effort to establish usable cutting scores for the Hebrew TMT. A ratio of 2.26 was observed to result in 63% sensitivity and 77% specificity for the sample, with positive predictive power of 71% and negative predictive power of 70%. A more stringent cutoff of 3.09 reduced sensitivity (22%) and negative predictive power (44%). In contrast, specificity (97%) and positive predictive power (86%) were greatly improved once the speed of TMT-A performance was also considered. The more conservative cutoff is considered appropriate when a finding is indicative of pathological performance.

Programmed cell death in Escherichia coli: some antibiotics can trigger mazEF lethality

The discovery of toxin-antitoxin gene pairs (also called addiction modules) on extrachromosomal elements of Escherichia coli, and particularly the discovery of homologous modules on the bacterial chromosome, suggest that a potential for programmed cell death may be inherent in bacterial cultures. We have reported on the E. coli mazEF system, a regulatable addiction module located on the bacterial chromosome. MazF is a stable toxin and MazE is a labile antitoxin. Here we show that cell death mediated by the E. coli mazEF module can be triggered by several antibiotics (rifampicin, chloramphenicol, and spectinomycin) that are general inhibitors of transcription and/or translation. These antibiotics inhibit the continuous expression of the labile antitoxin MazE, and as a result, the stable toxin MazF causes cell death. Our results have implications for the possible mode(s) of action of this group of antibiotics.

Molecular and antigenic characterization of a highly evolved derivative of the type 2 oral poliovaccine strain isolated from sewage in Israel

An unusual, highly diverged derivative of the Sabin type 2 oral poliovaccine (OPV) strain was recovered from environmental samples during routine screening for wild polioviruses. Virus was cultivated in L20B cells and then passaged on BGM cells at 40 degrees C (RCT [reproductive capacity at supraoptimal temperature]-positive marker) to select against most OPV strains. All but 1 of 25 RCT-positive OPV-derived environmental isolates were antigenically and genetically (>99.5% VP1 sequence match) similar to the respective Sabin strains. However, isolate PV2/4568-1/ISR98 (referred to below as 4568-1) escaped neutralization with Sabin 2-specific monoclonal antibodies and cross-adsorbed sera, and had multiple nucleotide substitutions (220 of 2,646; 8.3%) in the P1 capsid region. Fourteen of the 44 associated amino acid substitutions in the capsid mapped to neutralizing antigenic sites. Neutralizing titers in the sera of 50 Israeli children 15 years old were significantly lower to 4568-1 (geometric mean titer [GMT], 47) than to Sabin 2 (GMT, 162) or to the prototype wild strain, PV2/MEF-1/EGY42 (GMT, 108). Two key attenuating sites had also reverted in 4568-1 (A(481) to G in the 5' untranslated region and the VP1 amino acid I(143) to T), and the isolate was highly neurovirulent for transgenic mice expressing the poliovirus receptor (PVR-Tg21 mice). The extensive genetic divergence of 4568-1 from the parental Sabin 2 strain suggested that the virus had replicated in one or more people for approximately 6 years. The presence in the environment of a highly evolved, neurovirulent OPV-derived poliovirus in the absence of polio cases has important implications for strategies for the cessation of immunization with OPV following global polio eradication.

The effectiveness of NGO campaigning: lessons from practice

This article looks at the lessons learned in reviewing two long-running international campaigns, one to promote breast-feeding in Ghana, and the other against the use of child labor in the carpet industry in India. In particular, it focuses on understanding the nature of campaigns and what makes them effective. It asserts that campaigns are not linear or mechanistic, but need to be understood as passing through various stages and requiring different kinds of action at different levels and at different times. The variety of work and skills thus required makes it vital that the various organizations involved collaborate with each other. In particular, grassroots mobilization has a role that is often forgotten in bringing about sustained policy change.

Advance directives: older adults with dementia

The benefits and risks for older adults with dementia executing advance directives are discussed. Salient issues related to decision-specific capacity and models for advance planning and end-of-life decisions by cognitively impaired older adults are presented.

Total colectomy versus limited colonic resection for acute lower gastrointestinal bleeding

BACKGROUND

Acute lower gastrointestinal bleeding (ALGB) of the colon can be problematic to diagnose. The purpose of this study was to review our experience with ALGBs and to determine any differences between limited colon resection (LCR) and total/subtotal colon resection (TCR).

METHODS

A retrospective study located 77 patients with ALGB, who required 2 or more units of packed red blood cells prior to surgery, and who were taken to the operating room from 1987 to 1997.

RESULTS

Fifty LCRs and 27 TCRs were performed during this 10-year period. Recurrent bleeding was significantly more common in the LCR group than in the TCR group (18% versus 4%). Morbidity and mortality were not significantly different.

CONCLUSIONS

Owing to the misconception of a higher morbidity with TCR, it has been considered a "last resort" instead of a more expeditious therapy with similar morbidities and mortalities. TCR should be considered more often in the management of these patients.

Genetic variation of three tetrameric tandem repeats in four distinct Israeli ethnic groups

The allele frequency distributions of three STR loci amplified by PCR have been studied in four Israeli communities: Ashkenazi Jews and three non-Ashkenazi groups, namely Moroccan, Yemenite, and Ethiopian Jews. The loci analyzed were CSF1PO, TPOX, and HUMTHO1. The typing was performed in sequencing polyacrylamide gels under denaturing conditions that could separate alleles with differences of a single base. The population data were analyzed with respect to Hardy-Weinberg (H-W) equilibrium and found that all loci meet the H-W expectations. No-ticeable differences were encountered between the four Jewish ethnic groups studied hereby indicating the importance of establishing a local database to be used in human identity testing in these different Israeli Jewish groups.

A new variant of echovirus 4 associated with a large outbreak of aseptic meningitis

BACKGROUND

A large outbreak of aseptic meningitis which began in April 1997 involved hundreds of cases in all geographical regions of Israel and the Palestinian Authority, peaked between June and September, and lasted until December.

OBJECTIVES

We have investigated the virus associated with the outbreak to determine its serotype and molecular type and to establish epidemiological links.

DESIGN

Virus strains isolated from 210 clinical samples were serotyped by neutralization using LBM and WHO antiserum pools and two echovirus 4 (EV4)-specific antisera, and by immunofluorescence using a monoclonal antibody. RNA was extracted and a 435 base long fragment derived from the 5'UTR of the genome was amplified by RT-PCR using common primers, and sequenced. Sequences were compared to echoviruses 4, 6 and 7 prototypes from ATCC, and to other echoviruses sequences from the EMBL/Genbank data base.

RESULTS

The outbreak isolates were identified by the EV4 type-specific antisera and the monoclonal antibody but not with the WHO pools. Very few isolates could be typed by the LBM pools. The EV4 isolates accounted for 68% of all enterovirus isolates in our laboratory in 1997. The age distribution of the patients was: 0-11 month, 11.2%; 1-4 years, 16.1%; 5-9 years, 31.8%; 10-14 years, 9.9%; 15-20 years, 9.5%; 21-44 years, 21.5%; and > 45 years, 0%. Males between 1 and 14 years of age were affected more frequently than females of the same age. The sequences of 25 of 28 EV4 isolates analyzed were closely related to each other (> 95% homology) and the remaining three isolates had < 95% homology to the others and to each other. Interestingly, the outbreak strains were less closely related to the EV4 prototype, than to several other echoviruses. Three closely related subgroups were identified which correlated with geographical distribution but the temporal distribution did not reveal links leading to the source of the outbreak.

CONCLUSION

The outbreak was caused by a variant of EV4 which apparently did not circulate in the area before and thus was capable of causing a widespread infection.

Tolerance induction permits the development of graft-versus-host disease: donor-mediated attack following small bowel transplantation in mixed chimeras

The induction of tolerance to organ allografts would eliminate acute and chronic rejection as well as the need for nonspecific immunosuppression. We have shown that tolerance induced through the creation of mixed allogeneic bone marrow chimeras allows for the long-term engraftment of cardiac and small bowel allografts across strong multiple major histocompatibility barriers. The possibility that tolerance might render the host susceptible to graft-versus-host disease (GVHD) has not been investigated in this or other models of tolerance. To test this possibility chimeras were created by transplantation of T-cell depleted ACI and Lewis bone marrow into lethally irradiated Lewis rats. Chimerism was determined post bone marrow transplant (BMTx) by flow cytometry of lymphocytes from reconstituted animals. ACI/Lew chimeras (ALC), Lewis/ACI F1 (LACF1), and Lewis (LEW) rats all received heterotopic ACI vascularized small bowel grafts. A second group of chimeras received small bowel grafts from ACI rats pretreated with low dose irradiation to eliminate T-cells from the graft. LEW-->LEW small bowel isografts were also performed. Animals were examined for evidence of GVHD by clinical signs and histologic examination of biopsied tissues. GVHD was quantified using the popliteal lymph node enlargement assay. All LACF1 rats developed severe lethal GVHD following ACI small bowel transplant. Bone marrow chimeras, ALC (n = 6), developed fatal GVHD in a similar fashion after receiving a small bowel transplant. LEW-->LEW isografts and chimeras receiving bowel from irradiated ACI rats survived long term without GVHD while ACI-->LEW allogeneic transplants all underwent acute rejection. GVHD or its absence was confirmed histologically. Popliteal lymph node enlargement indices reflected the presence of GVHD in the chimeras (1.87) and LACF1 (5.4) receiving allografts, but not in isografts or chimeras receiving irradiated allogeneic transplants. Analysis of cytokines in the tongues of rats undergoing GVHD showed elaboration of Th1 type proinflammatory cytokines which was not seen in isografted rats or rats receiving preirradiated small bowel. These results demonstrate that tolerance induction through mixed chimerism results in susceptibility to small bowel induced GVHD. Preirradiating the donor bowel prior to SBTx can prevent GVHD.