Microwave Susceptibility Observation of Interacting Many-Body Andreev States

Electrostatic charging affects the many-body spectrum of Andreev states, yet its influence on their microwave properties has not been elucidated. We developed a circuit quantum electrodynamics probe that, in addition to transition spectroscopy, measures the microwave susceptibility of different states of a semiconductor nanowire weak link with a single dominant (spin-degenerate) Andreev level. We found that the microwave susceptibility does not exhibit a particle-hole symmetry, which we qualitatively explain as an influence of Coulomb interaction. Moreover, our state-selective measurement reveals a large, π-phase shifted contribution to the response common to all many-body states which can be interpreted as arising from a phase-dependent continuum in the superconducting density of states.

Radiolucent foreign bodies presenting as inflammatory bowel disease: the case of an ingested plastic straw disguising as Crohn's

More than 80% of ingested foreign bodies are thought to pass spontaneously in the faeces, with fewer than 1% requiring surgical intervention. 'Missed' gastrointestinal foreign bodies are rare and often due to the lack of an obtainable history in patients with communication difficulties or radiolucent foreign bodies. We present the rare case of a 27-year-old woman with severe learning difficulties and a complex surgical history who presented with a 2-year history of increasing abdominal discomfort due to a 'missed' foreign body. Initially diagnosed as Crohn's disease, this case highlights the value of oral contrast enhancement imaging in patients who do not fit a 'classical' inflammatory bowel disease presentation.

Duodenal volvulus: a rare cause of small bowel obstruction

Small bowel volvulus is a rare but life-threatening emergency. Volvulus of the duodenum is even rarer without the presence of predisposing factors. The clinical presentation is vague, including abdominal pain, nausea and vomiting, prompt diagnosis of volvulus therefore relies heavily on radiographs. The treatment options lie between conservative or surgical management, where the decision is influenced by the patient and their presentation. This case is of a 100-year-old female with an extensive surgical and medical background presenting with signs of small bowel obstruction. With the help of imaging, a rare case of duodenal volvulus was diagnosed but managed conservatively due to the patient's background, age and personal wishes.

1579 Effect of COVID-19 pandemic on the Suspected Colorectal Cancer Pathway at a District General Hospital

Aim

During the initial phase of the COVID-19 pandemic the British Society of Gastroenterology and Joint Advisory Group on GI Endoscopy published guidance to halt all non-emergency endoscopy. As a result, CT was used as the first-line investigation with delayed completion endoscopy. We reviewed the efficacy of this change to determine its influence on future practice.

Method

All patients referred via the suspected colorectal cancer pathway (SCCP) to our district general hospital from 15/04/20-15/05/20 (during the initial COVID-19 lockdown) were included. Retrospective analysis of patient electronic records, radiology and endoscopy was performed. Results were analysed using χ² statistic. Significant incidental pathology was defined as non-colorectal pathology requiring referral to different speciality or further imaging.

Results

115 patients were included for analysis, mean age 68 years. 2/115 (1.7%) were found to have a colorectal malignancy on CT, with no further diagnoses following completion colonoscopy. CT imaging detected significant incidental pathology in 31/115 (27%). Subgroup analysis by presenting complaint showed significant pathology was most likely to be detected in those presenting with weight loss (13/36, 36.1%, p = 0.049) or anaemia (12/31, 38.7% p = 0.084).

Conclusions

CT is a valuable first-line investigation in SCCP patients. In this cohort, no colorectal malignancies were missed on CT that were later detected on endoscopy and 27% of scans detected significant non-colorectal incidental pathology. Weight loss was found to have a statistically significant correlation with incidental pathology. These findings suggest CT as a possible first-line investigation in patients presenting with weight loss, anaemia or in the event of delayed access to endoscopy.

1491 Hemi-Nephroureterectomy For Duplex Kidney in Children - The Resulting Effect on Renal Function

Introduction

Urinary duplication systems occur in approximately 1% of the population, and may present with recurrent UTIs, incontinence, or be incidentally detected on imaging. DMSA (dimercaptosuccinic acid) imaging is used in these patients to assess split renal function. If found significantly reduced in a single moiety, children may be offered hemi-nephroureterectomy (HNU). We analysed the rate of remnant moiety loss following HNU comparing age and affected moiety.

Method

All HNUs performed at our paediatric tertiary centre 2005-2019 were analysed. Children <16yrs, with pre– and post-operative DMSA imaging were included. Renal loss was categorised as: significant (≥50% of pre-existing function), non-significant (≥25% pre-existing function), no renal loss (<25%), and complete loss (post-operative remnant moiety function ≤5%). Subgroup analysis was performed using χ² statistic.

Results

73 patients were included, mean age 2.1yrs. Median pre-operative function of the affected kidney was 42%. 12 patients (16.4%) had significant renal loss, 13 (17.8%) non-significant loss and 6 (8.2%) had complete renal loss. Children <2yrs had significant and complete renal loss more frequently than those aged ≥2yrs (9/35 and 5/35 vs 3/38 and 1/38 respectively, p = 0.069). Patients with upper moiety HNU (UMHNU) had higher rates of significant and complete renal loss than lower moiety HNU patients (12/53=significant, 6/53=complete vs 0/20 significant/complete, p = <0.05).

Conclusions

HNU for duplex kidney is associated with high rates of remnant moiety damage, with ¼ of patients experiencing significant or complete renal loss. Subgroup analysis suggests this risk is higher in children <2yrs or UMHNU. HNU should therefore only be reserved for symptomatic patients failing conservative management.

1582 Radiolucent Foreign Bodies Presenting As IBD- The Case of An Ingested Plastic Straw Disguising as Crohn’s Disease

Ingested foreign bodies (FBs) occur most commonly in children or adults with impaired neurological function. Overall, 80% are thought to pass spontaneously in the faeces, with around 20% requiring endoscopy and less than 1% requiring surgical intervention. ‘Missed’ gastro-intestinal FBs are rare and often due to the lack of an obtainable history in patients with communication difficulties.

We present the unusual case of a 27-year-old female with severe learning difficulties and a complex surgical history who presented with a 2-year history of increasing abdominal discomfort due to a ‘missed’ FB. Four CT scans had misdiagnosed Crohn’s disease and the patient was due to commence immunosuppression when she developed a small bowel perforation. This was managed conservatively and follow-up imaging with a CT with oral contrast detected the FB in the ileum. The patient underwent a laparotomy with resection of a 26cm segment of ileum containing a plastic straw. Post-operatively she recovered uneventfully and is now symptom free with no evidence of IBD on histology.

This case highlights the value of oral contrast enhancement imaging in patients who don’t fit a ‘classical’ inflammatory bowel disease presentation.

Coherent manipulation of an Andreev spin qubit

Two promising architectures for solid-state quantum information processing are based on electron spins electrostatically confined in semiconductor quantum dots and the collective electrodynamic modes of superconducting circuits. Superconducting electrodynamic qubits involve macroscopic numbers of electrons and offer the advantage of larger coupling, whereas semiconductor spin qubits involve individual electrons trapped in microscopic volumes but are more difficult to link. We combined beneficial aspects of both platforms in the Andreev spin qubit: the spin degree of freedom of an electronic quasiparticle trapped in the supercurrent-carrying Andreev levels of a Josephson semiconductor nanowire. We performed coherent spin manipulation by combining single-shot circuit-quantum-electrodynamics readout and spin-flipping Raman transitions and found a spin-flip time T _S = 17 microseconds and a spin coherence time T _2E = 52 nanoseconds. These results herald a regime of supercurrent-mediated coherent spin-photon coupling at the single-quantum level.

505 A Single Center Cohort Observational Study to Assess The Surgical Admissions During COVID-19 And Recommendations For Redeployment Of The Surgical Workforce

Introduction

The redeployment of the surgical workforce to support other frontline specialties was an integral part of the nationwide response to the COVID-19 pandemic. The R number is gradually increasing in different parts of the UK suggesting a second wave is imminent. Aimed to analyze the surgical emergency workload and provide recommendations for future redeployments.

Method

Three separate cohorts of adult emergency admissions; emergency admissions prior to lockdown (23^rd of February to 22^nd of March), 1 month after (23^rd of March to 22^nd of April) and 2 months after (23^rd of April to 22^nd of May). Data was collected regarding patient characteristics, duration of symptoms prior to presentation, clinical outcomes and compared between these groups.

Results

Notable initial decrease in admission per day (4.3 to 2.5) and interventional management (30%) during the 1^st month of lockdown. A marked increase in 24-hour discharge rate (50%). These parameters begun to normalize by the 2^nd month. The rate of overall conservative management gradually increased from 36.7% pre-lockdown to 60.9% at the 2^nd month.

Conclusions

Providing elective work is cancelled, surgical teams could safely tolerate working with 30%-40% of original staffing level, which will need to be gradually increased to 50%-70% after 1 month.

5,6,7,8-Tetrahydro-1,6-naphthyridine Derivatives as Potent HIV-1-Integrase-Allosteric-Site Inhibitors

A series of 5,6,7,8-tetrahydro-1,6-naphthyridine derivatives targeting the allosteric lens-epithelium-derived-growth-factor-p75 (LEDGF/p75)-binding site on HIV-1 integrase, an attractive target for antiviral chemotherapy, was prepared and screened for activity against HIV-1 infection in cell culture. Small molecules that bind within the LEDGF/p75-binding site promote aberrant multimerization of the integrase enzyme and are of significant interest as HIV-1-replication inhibitors. Structure-activity-relationship studies and rat pharmacokinetic studies of lead compounds are presented.

Anti-inflammatory effects of novel barbituric acid derivatives in T lymphocytes

We have used a high throughput small molecule screen, using a fission yeast-based assay, to identify novel phosphodiesterase 7 (PDE7) inhibitors. One of the most effective hit compounds was BC12, a barbituric acid-based molecule that exhibits unusually potent immunosuppressive and immunomodulatory actions on T lymphocyte function, including inhibition of T cell proliferation and IL-2 cytokine production. BC12 treatment confers a >95% inhibition of IL-2 secretion in phytohaemagglutinin (PHA) plus phorbol-12-myristate-13-acetate (PMA) stimulated Jurkat T cells. The effect of BC12 on IL-2 secretion is not due to decreased cell viability; rather, BC12 blocks up-regulation of IL-2 transcription in activated T cells. BC12 also inhibits IL-2 secretion in human peripheral T lymphocytes stimulated in response to CD3/CD28 co-ligation or the combination of PMA and ionomycin, as well as the proliferation of primary murine T cells stimulated with PMA and ionomycin. A BC12 analog that lacks PDE7 inhibitory activity (BC12-4) displays similar biological activity, suggesting that BC12 does not act via PDE7 inhibition. To investigate the mechanism of inhibition of IL-2 production by BC12, we performed microarray analyses using unstimulated and stimulated Jurkat T cells in the presence or absence of BC12 or BC12-4. Our studies show these compounds affect the transcriptional response to stimulation and act via one or more shared targets to produce both anti-inflammatory and pro-stress effects. These results demonstrate potent immunomodulatory activity for BC12 and BC12-4 in T lymphocytes and suggest a potential clinical use as an immunotherapeutic to treat T lymphocyte-mediated diseases.

Shielded Coaxial Optrode Arrays for Neurophysiology

Recent progress in the study of the brain has been greatly facilitated by the development of new tools capable of minimally-invasive, robust coupling to neuronal assemblies. Two prominent examples are the microelectrode array (MEA), which enables electrical signals from large numbers of neurons to be detected and spatiotemporally correlated, and optogenetics, which enables the electrical activity of cells to be controlled with light. In the former case, high spatial density is desirable but, as electrode arrays evolve toward higher density and thus smaller pitch, electrical crosstalk increases. In the latter, finer control over light input is desirable, to enable improved studies of neuroelectronic pathways emanating from specific cell stimulation. Here, we introduce a coaxial electrode architecture that is uniquely suited to address these issues, as it can simultaneously be utilized as an optical waveguide and a shielded electrode in dense arrays. Using optogenetically-transfected cells on a coaxial MEA, we demonstrate the utility of the architecture by recording cellular currents evoked from optical stimulation. We also show the capability for network recording by radiating an area of seven individually-addressed coaxial electrode regions with cultured cells covering a section of the extent.

Adjusting Local Molecular Environment for Giant Ambient Thermal Contraction

A low-energy triggered switch that can generate mechanoresponse has great technological potential. A submolecular moiety, S-dibenzocyclooctadiene (DBCOD) that is composed of a flexible eight-membered ring connecting to a phenyl ring at each end, undergoes a conformational change from twist-boat to chair under a low-energy stimulus such as near infrared irradiation, resulting in thermal contraction of DBCOD-based polymer. Experimental evidence corroborated by theoretical calculations indicates that introducing molecular asymmetry can reduce crystallinity significantly and consequently facilitate the kinetics of the conformational change. It has been demonstrated that the negative thermal expansion (NTE) coefficient of a DBCOD-based polymer system can be adjusted in a range from -1140 to -2350 ppm K^-1 . -2350 ppm K^-1 is ≈10 times better than the value reported by the second best NTE system.

The role of nutrients in B lymphocyte growth and survival responses

B cell activation is an energetically demanding process during which B lymphocytes shift from a resting state to a proliferative, metabolically active state. Little is known about the metabolic reprogramming process or the role extracellular nutrients play in the activation response. We demonstrate that there are distinct requirements for the nutrients L-glutamine and glucose during activation. We show that cells activated in glucose-depleted conditions are still able to undergo growth and signaling events. In contrast, we show that extracellular L-glutamine is essential for all but the earliest activation events, and cells cultured in L-glutamine-deprived conditions are unable to enter the cell cycle. Consistently, we show that extracellular supplementation of the cell-permeable derivative of a-ketoglutarate (a-KG) is able to rescue cell activation in the absence of glutamine. We also show the induction of the high affinity amino acid transporter ASCT2 is required for glutamine uptake following BCR crosslinking. Specifically, we found that halting glutamine uptake or processing by inhibiting ASCT2 or the glutaminolytic enzyme glutaminase causes activation defects that parallel those observed in glutamine deprived conditions, indicating a requirement for glutaminolysis during the very early stages of activation. Finally, we found that a-KG does not contribute to epigenetic remodeling, but is necessary for mTORC1 activation. In turn, mTORC1 activity is required for upregulation of the glucose transporter Glut1 during activation, as well as increased glucose uptake. These findings indicate a distinct metabolic profile that begins with glutamine uptake, and acts through mTORC1 signaling to later promote glucose uptake.

Creutzfeldt-Jakob disease mortality in Canada, 1998 to 2013

BACKGROUND

Human prion diseases, known collectively as Creutzfeldt-Jakob disease (CJD), are fatal, infectious neurodegenerative disorders that occur in all human populations.

OBJECTIVE

To summarize national surveillance data for CJD in Canada between January 1, 1998, and December 31, 2013.

METHODS

Detailed investigations were conducted of individual suspected CJD cases, with collaboration between Canadian health professionals and investigators affiliated with a central CJD surveillance registry operated by the Public Health Agency of Canada. Data were collected on the clinical profile, family history, and results of paraclinical and laboratory investigations, including post-mortem neuropathological examination.

RESULTS

A total of 662 deaths from definite and probable CJD were identified in Canadian residents during the study period, comprising 613 cases of sporadic CJD (92.6%), 43 cases of genetic prion disease (6.5%), 4 cases of iatrogenic CJD (0.6%), and 2 cases of variant CJD disease (0.3%). The overall crude mortality rate for sporadic CJD was 1.18 per million per year [95% confidence interval (CI): 1.08,1.27]. Age-specific rates ranged from 0.05 [95% CI: 0.03,0.08] in persons under 50 years of age to 7.11 [95% CI: 6.20,8.11] in those aged 70 to 79. A significant net upward trend in age-adjusted rates was observed over the study period. Standardized mortality ratios, calculated for 10 individual Canadian provinces with reference to national average mortality rates, did not differ significantly from 1.0.

CONCLUSION

Creutzfeldt-Jakob disease remains rare in Canada, although mortality rates vary by two orders of magnitude between older and younger age groups. The upward trend in age-standardized sporadic CJD mortality rate over the study period can be better accounted for by gradually improving case ascertainment than by a real increase in incidence.

The regulation and role of L-glutamine in B-lymphocyte activation (LYM7P.618)

B lymphocyte activation is a highly energetic event that promotes cell survival and growth. Aberrant activation of B lymphocytes can lead to disease states such as lymphomas or autoimmune diseases. To meet the metabolic demands of activation, B cells increase nutrient uptake to provide energy and intermediates for macromolecule synthesis. We have investigated the role of L-glutamine, which is emerging as a critical immunomodulatory nutrient; however, the precise role of L-glutamine in B cell growth responses is poorly understood. Depletion of extracellular L-glutamine results in impaired cell growth and proliferation in response to B-cell antigen receptor (BCR) ligation, although, early activation events such as induction of CD86 are unaffected. We show that L-glutamine uptake is induced in response to BCR ligation. This corresponds to an increase in the surface expression of the high affinity L-glutamine transporter, ASCT2, indicating its involvement in L-glutamine uptake. Further, inhibition of ASCT2 by the small molecule N-glutaryl-L-phenylalanine p-nitroanilide (GPNA) caused impaired B lymphocyte activation similar to that observed in response to L-glutamine depletion. The addition of L-leucine abated some of the effects of GPNA treatment on B lymphocyte growth responses, indicating mTORC involvement. These data provide new insight on the requirement of L-glutamine in B lymphocyte activation and suggest a possible underlying mechanism of growth regulation by mTORC.

Distribution and fine-scale spatial-genetic structure in British wild cherry (Prunus avium L.)

Insights into the within-population spatial-genetic structure (SGS) of forest tree species, where little is known regarding seed and pollen dispersal patterns, enhance understanding of their ecology and provide information of value in conservation and breeding. This study utilised 13 polymorphic simple sequence repeat loci to investigate the impact of asexual recruitment, management regime and tree size on the development of SGS in wild cherry (Prunus avium L). Only 246 genotypes were identified in the 551 trees sampled, reflecting significant levels of clonal reproduction in both managed and unmanaged populations. Naturally regenerated wild cherry was spatially aggregated under both management regimes. However, in the managed population, sexually derived trees accounted for a greater proportion of the smaller size classes, whereas vegetatively produced trees dominated the smaller size classes in the unmanaged population. High overall SGS values (Sp 0.030-Sp 0.045) were observed when considering only sexually derived genets and kinship coefficients were significant up to the 120 m distance class for both populations. The inclusion of clonal ramets in the analysis significantly increased the overall SGS (Sp 0.089-Sp 0.119) as well as kinship coefficients in the 40-80 m distance classes, illustrating the dramatic impact of vegetative propagation on SGS in this species. Increased spatial aggregation and regeneration appeared to be concomitant with increased SGS in the 40 m distance class in the unmanaged population. Neighbourhood size estimates were relatively small for both populations and kinship coefficients were found to decline with distance under both management regimes, suggesting that common mechanisms may restrict gene dispersal in wild cherry.

Effect of Moisture and Temperature on Disease of Green Foxtail Caused by Drechslera gigantea and Pyricularia setariae

Leaf wetness duration, temperature, intermittent leaf wetness, and delayed leaf wetness were investigated for their influence on disease of green foxtail caused by Drechslera gigantea and Pyricularia setariae to determine the potential of these two fungi as bioherbicide agents in the Canadian prairies. For both fungi, disease severity increased with increasing leaf wetness duration at 15, 20, 25, 30, and 32°C. At 10°C, conidia of both fungi showed minimal germination, regardless of leaf wetness duration; however, an increase in conidial germination, appressoria formation, and disease occurred at 15°C. Conidia of both species showed 80% or greater germination at all temperatures above 15°C, whereas the optimum temperatures for appressoria formation by D. gigantea and P. setariae were 23 and 25°C, respectively. Maximum disease occurred after 48 h of leaf wetness at 32°C for D. gigantea and at 25°C for P. setariae. Disease caused by both fungi decreased when 4 h of continuous leaf wetness was followed by a 20-h dry period, and after an 8-h delay in leaf wetness following inoculation. Both fungi required immediate and prolonged periods of leaf wetness at temperatures of 15°C and above to cause severe disease on green foxtail. The moisture requirements of these fungi may limit their effectiveness as bioherbicide agents in the semi-arid Canadian prairies.

Identification of genes regulated during osteoblastic differentiation by genome-wide expression analysis of mouse calvaria primary osteoblasts in vitro

Although several independent studies of gene expression patterns during osteoblast differentiation in cultures from calvaria and other in vitro models have been reported, only a small portion of the mRNAs expressed in osteoblasts have been characterized. We have previously analyzed the behavior of several known markers in osteoblasts, using Affymetrix GeneChip murine probe arrays (27,000 genes). In the present study we report larger groups of transcripts displaying significant expression modulation during the culture of osteoblasts isolated from mice calvaria. The expression profiles of 601 such regulated genes, classified in distinct functional families, are presented and analyzed here. Although some of these genes have previously been shown to play important roles in bone biology, the large majority of them have never been demonstrated to be regulated during osteoblast differentiation. Despite the fact that the precise involvement of these genes in osteoblast differentiation and function needs to be evaluated, the data presented herein will aid in the identification of genes that play a significant role in osteoblasts. This will provide a better understanding of the regulation of osteoblast differentiation and maturation.

Molecular characterization of antigen-induced lung inflammation in a murine model of asthma

Asthma is one of the foremost contributors to morbidity and mortality in industrialized countries. Our objective was to characterize the acute response to allergen and to identify potentially novel molecular targets for pharmacological intervention in asthma. We therefore designed a study to identify genes whose regulation was altered following ovalbumin (OVA) challenge in the presence and absence of treatment with glucocorticoids in BALB/c mice. RNA was isolated from lungs for gene profiling from 8-week-old sensitized mice, 3 and 18 hours post OVA challenge on days 1, 4, and 7 of aerosol challenge. Taqman (real time RT-PCR) analysis of marker genes indicative of Th2 (IL-4, IL-13), eosinophil (RANTES, eotaxin), Th1/macrophage (IFNgamma) and epithelial cell (MUC5AC) phenotypes were used to characterize responses to allergen challenge. Histological evaluation of lungs from additional challenged animals revealed inflammatory infiltrates on days 4 and 7, but not on day 1 post challenge. We postulate that expression of IL-4, IL-13 and other genes by OVA at day 1 probably reflects activation of resident cells, whereas the fivefold increase in the number of regulated genes at day 7 reflects the contribution of recruited cells. Of the regulated genes, only a subset was counter-regulated by dexamethasone treatment. Although regulated genes included genes in many protein families, herein we report regulation of two proteases whose role in response to OVA challenge has not been characterized. This model will be used to generate disease hypotheses for which may play an important role in initiating disease pathology in this model.

Behavior of osteoblast, adipocyte, and myoblast markers in genome-wide expression analysis of mouse calvaria primary osteoblasts in vitro

Several genes, such as alkaline phosphatase, osteocalcin, and Cbfa1/Osf2, are known to be regulated during osteoblastic differentiation and are commonly used as "osteoblast markers" for in vitro or in vivo studies. The number of these genes is very limited, however, and it is of major interest to identify new genes that are activated or repressed during the process of osteoblast differentiation and bone formation as well as to extend the available information on gene families relevant to this particular differentiation pathway. To identify such genes, we have implemented a genome-wide analysis by determining changes in expression levels of 27,000 genes during in vitro differentiation of primary osteoblasts isolated from mouse calvaria. This study focuses on the description of the analytical and filtering process applied; on the transcriptional analysis of well-established "bone," "adipocyte," and "muscle" pathway markers; and on a description of the regulation profiles for genes recently described in the Skeletal Gene Database. We also demonstrate that new array technologies constitute reliable and powerful tools to monitor the transcription of genes involved in osteoblastic differentiation, allowing a more integrated vision of the biological pathways regulated during osteoblast commitment, differentiation, and function.

Accuracy of the TDx-FLM assay of amniotic fluid: a comparison of vaginal pool samples with amniocentesis

OBJECTIVE

The purpose of this study was to evaluate the use of the TDx-FLM fluorescence polarization assay on vaginal pool fluid in patients with preterm premature rupture of membranes (PPROM).

METHODS

A prospective matched-pairs study was performed at a tertiary care center. For each patient enrolled, amniotic fluid samples were obtained by sterile speculum examination and by amniocentesis within 12 h of each other. Inclusion criteria were the presence of PPROM and a gestational age of 30-36 weeks. The samples were analyzed separately using the TDx-FLM assay in the same laboratory. The results were compared using a paired Student t test.

RESULTS

A total of 16 patients received both amniocentesis and vaginal collection of amniotic fluid. The mean gestational age at amniocentesis was 33.3 weeks (SD 1.9). In every case, the vaginal pool TDx-FLM result was lower than the amniocentesis result. The mean difference in the assays between the two fluid sources was 35% (range 17-63%, p < 0.001). Amniocentesis suggested a mature result in 12 cases (75%), an indeterminate result in two cases (12.5%), and an immature result in two cases (12.5%). Vaginal pool fluid suggested a mature result in four cases (25%), an indeterminate result in nine cases (56%), and an immature result in three cases (19%). Using the cut-off values validated for amniocentesis specimens as a standard for comparison, vaginal pool TDx-FLM assay had 42% sensitivity, 100% specificity, 100% positive predictive value and 36% negative predictive value for predicting lung maturity.

CONCLUSIONS

The TDx-FLM assay on vaginal pool samples of amniotic fluid yielded results that were significantly different from those of amniocentesis samples. At this point, the assay is only clinically useful for vaginal pool samples when a mature result is obtained.

Efficient cloning of full-length cDNAs based on cDNA size fractionation

The ability to generate and obtain full-length (FL) cDNAs is of critical importance to the field of genomics. Most cDNAs in a traditional cDNA library lack the initiating 5' ATG, making it difficult to obtain a FL clone. We report here on an improved protocol for the preparation of FL enriched cDNA libraries. We demonstrate that if good quality RNA is used in the cDNA synthesis, high-quality, FL cDNA can be generated for messages upward of 7 kb. In addition, we demonstrate the utility of size fractionation as a means to produce libraries containing a high percentage of initiating 5' ATG containing clones with insert sizes greater than 4 kb. The method is simple, cost efficient, and can be performed in most laboratories equipped to perform molecular biology. Lastly, the novel methodologies used in the analysis of the cDNA and library should prove useful to others working to create high-quality cDNA libraries.

Finding genes in the C2C12 osteogenic pathway by k-nearest-neighbor classification of expression data

A supervised classification scheme for analyzing microarray expression data, based on the k-nearest-neighbor method coupled to noise-reduction filters, has been used to find genes involved in the osteogenic pathway of the mouse C2C12 cell line studied here as a model for in vivo osteogenesis. The scheme uses as input a training set embodying expert biological knowledge, and provides internal estimates of its own misclassification errors, which furthermore enables systematic optimization of the classifier parameters. On the basis of the C2C12-generated expression data set with 34,130 expression profiles across 2 time courses, each comprised of 6 points, and a training set containing known members of the osteogenic, myoblastic, and adipocytic pathways, 176 new genes in addition to 28 originally in the training set are selected as relevant to osteogenesis. For this selection, the estimated sensitivity is 42% and the posterior false-positive rate (fraction of candidates that are spurious) is 12%. The corresponding sensitivity and false-positive rate for detection of myoblastic genes are 9% and 31%, respectively, and only 4% and approximately 100%, respectively, for adipocytic genes, in accordance with an experimental design that predominantly stimulated the osteogenic pathway. Validation of this selection is provided by examining expression of the genes in an independent biological assay involving mouse calvaria (skull bone) primary cell cultures, in which a large fraction of the 176 genes are seen to be strongly regulated, as well as by case-by-case analysis of the genes on the basis of expert domain knowledge. The methodology should be generalizable to any situation in which enough a priori biological knowledge exists to define a training set.

The genetic structures of a range of Douglas-fir provenance collections after planting in different European countries, assessed with two biochemical marker systems

Genetic diversities of Douglas-fir provenance trials planted on several European sites were compared using both isozyme and terpene markers. A principal coordinate analysis based on similarity coefficients calculated from isozyme data indicated that, with the exception of two populations, differences between populations were small. There were no consistent trends in the variation in allele frequencies between populations. Most populations contained an excess of homozygotes, perhaps due to high selection pressure. Terpene composition was analysed in two resin systems, and showed a decreasing level of population diversity by planting site in the order: Spain-France-England-Scotland-Italy. Thus isozymes, which are generally considered to be neutral markers, indicated a modest degree of genetic drift due to sampling effects, while terpenes showed that some reduction in genetic diversity had occurred due to local selective pressures.

Tobacco cessation skills certification in Arizona: application of a state wide, community based model for diffusion of evidence based practice guidelines

OBJECTIVE

To describe the development and preliminary results from a community based certification model for training in tobacco cessation skills in Arizona.

DESIGN

A programme evaluation using both quantitative pre-post measures and qualitative methods.

SETTING

Arizona's comprehensive tobacco control programme of state funded, community based local projects and their community partners providing tobacco treatment services for geographically, socioeconomically, and ethnically diverse communities.

INTERVENTION

A three tiered model of skills based training emphasising Agency for Health Care Policy and Research guidelines, and utilising a training of trainers approach to build community capacity. Certification roles addressed basic tobacco cessation skills, tobacco cessation specialist, and tobacco treatment services manager.

PARTICIPANTS

Initial target audience was community based local project personnel and their community partners, with later adoption by community organisations unaffiliated with local projects, and the general public. MAIN EVALUATION MEASURES: Process measures: participant satisfaction, knowledge, skills, and self-efficacy.

OUTCOME

participant demographics, community organisations represented, post-training, cessation related activities.

RESULTS

During the model's implementation year, 1075 participants attended certification training, 947 participants received basic skills certificates and 82 received specialist certificates. Pre, post, and three month measures of self efficacy showed significant and durable increases. Analysis of participant characteristics demonstrated broad community representation. At post-training follow up, 80.9% of basic skills trainees had performed at least one brief intervention and 74.8% had made a referral to intensive services. Among cessation specialists, 48.8% were delivering intensive services and 69.5% were teaching basic skills classes.

CONCLUSIONS

Initial experience with Arizona's state wide, community based model for certification of tobacco cessation skills training suggests this model may be a promising method for broad, population based diffusion of evidence based tobacco cessation guidelines.

Synergistic anti-tumor activity of a novel immunomodulator, BCH-1393, in combination with cyclophosphamide

N,N-dimethylaminopurine pentoxycarbonyl D-arginine (BCH-1393) is a novel low molecular weight synthetic immunomodulator that has been shown to significantly stimulate cytotoxic T-lymphocyte responses both in vitro and in vivo (Zacharie B, Gagnon L, Attardo G, Connolly TP, St-Denis Y, Penney CL. Synthesis and activity of 6-substituted purine linker amine immunostimulants. J. Med. Chem. 1997;40:2883-94). Prompted by this evidence, we extended evaluation of BCH-1393 for anticancer activity in syngeneic mouse experimental tumor models. Consistent with previous findings, in vitro assessment of BCH-1393 activity demonstrated a significant increase in the CTL responses in the range of 10(-9)-10(-5) M. Treatment of mice with four consecutive daily intraperitoneal injections at 25 and 50 mg/kg resulted in a significant increase of the relative percentage of blood CD4+, CD8+, NK and monocyte subsets without any evidence of toxicity. In vivo anti-tumor activity of BCH-1393 was evaluated, either alone or in combination with subtherapeutic doses of cyclophosphamide (Cy), against weakly immunogenic mouse breast carcinoma DA-3 and strongly immunogenic colon adenocarcinoma MC38. Daily intraperitoneal injection of BCH-1393 at 50 mg/kg alone was well tolerated but produced a relatively weak anti-tumor effect in both tumor models. However, a significant inhibition of tumor outgrowth and suppression of established tumor growth was observed when BCH-1393 was administered in combination with subtherapeutic doses of Cy. Combination treatment of 50 mg/kg BCH-1393 with 100 mg/kg Cy (given as single intravenous bolus injection) starting 2 days prior to DA-3 tumor cell inoculation prevented tumor outgrowth in 70-80% of treated mice. In the remaining 20-30% of mice that had developed tumors, a nearly complete (90%) tumor growth inhibition was observed at days 22-24 post tumor implant. In the MC38 tumor model, combination treatment of established tumors with BCH-1393 and Cy (CTX) at 50 mg/kg resulted in a significant delay in tumor growth compared to CTX treatment alone. The observed concomitant anti-tumor activity of BCH-1393 with cyclophosphamide warrants further investigation of this immunomodulator as an adjunctive treatment of cancer.

Regret and Responsibility: A Reply to Zeelenberg et al. (1998)

M. Zeelenberg, W. W. van Dijk, and A. S. R. Manstead (1998, Organizational Behavior and Human Decision Processes, 74, 254-272) recently reported an altered replication of our earlier study (T. Connolly, L. D. Ordóñez, & R. Coughlan, 1997, Organizational Behavior and Human Decision Processes, 70, 73-85) concerning the effects of decision agency on regret and outcome evaluation. Our earlier study had found no such effect, but Zeelenberg et al. did. In two new experiments, we have largely confirmed Zeelenberg et al.'s result but have shown that, contrary to most theory, regret (a) can appear even in the absence of decision agency, (b) can be unrelated to outcome evaluations, and (c) may be more influenced by the experience of gains or losses from the status quo than by any decisional responsibility for those changes. Copyright 2000 Academic Press.

Impact of physicians' perceptions of malpractice and adaptive changes on intention to cease obstetrical practice

Physicians who provide obstetrical care in rural areas face exposure to liability action and confront a critical decision--whether to continue to offer these services. This paper draws upon social-psychological and decision theories to investigate this decision. Ninety-four percent of all obstetricians and family and general physicians practicing in the 12 nonmetropolitan counties of one state responded to a mail survey that asked about their intention to continue or discontinue obstetrical practice, two dimensions of subjective risk (perceived likelihood of threats in the malpractice environment and perceived magnitude of negative consequences from being sued), and adaptive changes to protect against malpractice. The results suggest that (a) perceived extent of negative consequences (but not perceived likelihood of malpractice threats) drives intention to leave obstetrics, (b) the professional and reputational impacts of a suit--not the dollar amount of award or settlement--predicts intention to stop practicing obstetrics, and (c) physicians planning to continue providing obstetrical care in the future have made recent practice changes that may further exacerbate access problems.

The treatment perspectives of physicians, citizens, and state legislators

This study addresses the dilemma of physicians to act both as an agent of their patients and as an agent of society. We contrasted the perceptions of physicians, citizens at large, and state legislators about 11 topics related to physician decision making regarding the management of care for seriously ill patients. Significant and interpretable differences were found between physicians and citizens, although there were no differences between these two groups and the state legislators. However, even the obtained differences were fewer and smaller than expected. These results suggest that lay, legislative, and medical viewpoints may be less at odds with each other than the literature would suggest, and reaching an accord on at least some aspects of health policy may not be as difficult as generally is assumed.

p21(cip1) rescues human mesenchymal stem cells from apoptosis induced by low-density culture

Mammalian cells are programmed to undergo programmed cell death in response to a variety of conditions. We demonstrate that human mesenchymal stem cells (hMSCs) undergo programmed cell death upon seeding at low density. Under these conditions, we observed an increased proportion of cells in S-phase and a decreased proportion of cells in G1-phase. This indicated that a change in control of G1-S-phase transition in response to low-density seeding had occurred and, therefore, we measured the level of cyclin-dependent kinase inhibitory proteins governing this transition. Human MSCs cultured at low density exhibited lowered levels of both the p21 and p27 cyclin-dependent kinase inhibitors, and these protein levels appear to be regulated at a post-transcriptional level. Conversely, overexpression of the p21 cell cycle-dependent kinase inhibitor but not that of p27 protected hMSCs from programmed cell death upon culture at low density. Furthermore, p21 and p27 are expressed differentially during endochondrial bone development. The loss of p21 in hypertrophic chondrocytes correlates with the onset of apoptosis during endochondrial ossification. We suggest that p21 and p27 play a central role in skeletal development.

The influence of psychosocial factors on heart transplantation decisions and outcomes

In January 1990, a well-established heart transplant program added a psychosocial evaluation procedure to its medical evaluation of potential transplant recipients. To determine the predictive value of psychosocial evaluation for decisions to list patients for a transplant and for ultimate clinical outcomes, we reviewed records of 191 patients who underwent psychosocial evaluation in the subsequent 3 years. Informal prescreening for obvious psychopathology and other disqualifiers almost certainly restricted the ranges of psychosocial factors observed in the sample. Of 120 patients listed, 61 actually received transplants. Psychosocial factors were little used in deciding whether to list the patients and were not predictive of recipients' medical outcome or compliance, but were moderately predictive of complication rates and difficulty of managing patients after transplantation. Although psychosocial evaluation of prescreened potential transplant recipients has little value in predicting medical outcome, it may be useful for planning and scheduling care after transplantation.

Responses of cells and protoplasts of Coffea arabica genotypes to partially purified culture filtrates produced by Colletotrichum kahawae

Hypocotyl-derived calli of genotypes and segregating populations of Coffea arabica, differing in susceptibility to Colletotrichum kahawae, were used to produce cell suspensions and protoplasts which were exposed to partially purified culture filtrates (PPCFs) prepared from the pathogen. The growth and viability of PPCF-treated cells and protoplasts were measured using packed cell volume, fluorescein diacetate staining and a colorimetric assay involving the tetrazolium salt MTT. Differential responses of cells and protoplasts were influenced by genotype, time of exposure and PPCF concentration. Protoplasts of resistant genotypes responded differentially from more susceptible genotypes as early as 4 h after challenge with the phytotoxin, suggesting that they were more sensitive than cell suspensions to the treatments. Protoplasts exposed to PPCFs from C. kahawae may therefore be used to screen and select genotypes resistant to, or tolerant of, coffee berry disease.

Reduced folate carrier gene (RFC1) expression and anti-folate resistance in transfected and non-selected cell lines

Methotrexate transport deficiency due to decreased reduced folate carrier (RFC) activity has been observed in several cell lines selected for resistance to methotrexate (MTX). Since MTX resistance is multifactorial, however, it is difficult to quantify the relative importance of changes in RFC activity in selected cell lines and even more so to determine the relative contribution of naturally occurring RFC activity in the MTX sensitivity of non-selected cell lines. We examined the role of RFC in MTX resistance by studying a transport-deficient cell line transfected with the gene for human RFC, RFC1, and by correlating relative RFC1 expression with MTX and trimetrexate (TMTX) growth inhibition (GI50) in a panel of cell lines used in the NCI Anticancer Drug Screen. Clones of transport-deficient, MTX-resistant ZR-75-1 human breast cancer cells (MTX(R) ZR-75-1) transfected with RFC1 were 250-fold more sensitive to MTX and 300-fold more resistant to TMTX than control cell clones, showing that restoration of RFC activity has a significant impact on MTX and TMTX cytotoxicity. We also surveyed 40 of the 60 cell lines in the NCI drug screen panel for RFCI RNA levels by a quantitative RT-PCR assay. RFCI RNA levels varied over a range of 15-fold, with only 1 cell line found to be null in expression. Using data from the 6-day drug exposure assay, RFC1 correlated positively with MTX and negatively with TMTX cytotoxicity. As predicted by transfection studies, the calculated difference between MTX and TMTX potency was even more strongly correlated with RFC1 RNA levels of the cell lines. In addition, compounds in the NCI Anticancer Drug Screen database with cytotoxicity profiles which correlated with RFC1 RNA levels or with the calculated difference in MTX-TMTX potency were examined for MTX uptake inhibition and cytotoxicity in the RFC1-transfected MTX(R) ZR-75-1 cell line. Overall, our data demonstrate the importance of RFC1 in MTX resistance both as a transgene and as a constitutively expressed gene in non-selected cell lines.

Ran1 functions to control the Cdc10/Sct1 complex through Puc1

We have undertaken a biochemical analysis of the regulation of the G1/S-phase transition and commitment to the cell cycle in the fission yeast Schizosaccharomyces pombe. The execution of Start requires the activity of the Cdc2 protein kinase and the Sct1/Cdc10 transcription complex. Progression through G1 also requires the Ran1 protein kinase whose inactivation leads to activation of the meiotic pathway under conditions normally inhibitory to this process. We have found that in addition to Cdc2, Sct1/Cdc10 complex formation requires Ran1. We demonstrate that the Puc1 cyclin associates with Ran1 and Cdc10 in vivo and that the Ran1 protein kinase functions to control the association between Puc1 and Cdc10. In addition, we present evidence that the phosphorylation state of Cdc10 is altered upon inactivation of Ran1. These results provide biochemical evidence that demonstrate one mechanism by which the Ran1 protein kinase serves to control cell fate through Cdc10 and Puc1.

The Cdc2 protein kinase controls Cdc10/Sct1 complex formation

In the fission yeast Schizosaccharomyces pombe, the execution of Start requires the activity of the Cdc2 protein kinase and the Cdc10/Sct1 transcription complex. The loss of any of these genes leads to G1 arrest and activation of the mating pathway under appropriate conditions. We have undertaken a genetic and biochemical analysis of these genes and their protein products to elucidate the molecular mechanism that governs the regulation of Start. We demonstrate that serine-196 of Cdc10 is phosphorylated in vivo and provide evidence that suggests that phosphorylation of this residue is required for Cdc10 function. Substitution of serine-196 of Cdc10 with alanine (Cdc10 S196A) leads to inactivation of Cdc10. We show that Cdc10 S196A is incapable of associating with Sct1 to form a heteromeric complex, whereas substitution of this serine with aspartic acid (S196D) restores DNA-binding activity by allowing Cdc10 to associate with Sct1. Furthermore, we demonstrate that Cdc2 activity is required for the formation of the heteromeric Sct1/Cdc10 transcription complex and that the Cdc10 S196D mutation alleviates this requirement. We thus provide biochemical evidence to demonstrate one mechanism by which the Cdc2 protein kinase may regulate Start in the fission yeast cell cycle.

Regret and Responsibility in the Evaluation of Decision Outcomes

The negative affect associated with bad decision outcomes is often thought to involve feelings of remorse or self-blame. For example, studies showing greater regret associated with active than with passive choice are interpreted as the active chooser piling self-recrimination on top the disappointment of a poor outcome. Corresponding rejoicing is postulated for active choice that leads to good outcomes. The five experiments reported here challenge such a view. In each, hypothetical individuals experienced identical gains or losses, some as a result of their own choice, others as a result of an external, arbitrary process. Though evaluations of final outcomes were heavily influenced by the paths by which the outcomes were reached, and by the comparison levels that were evoked, in no case was decision agency a significant influence. In these experiments, then, the "active chooser" effect appears more a matter of change than of choice, of the route taken rather than whether one is the driver or the passenger. Further research will be needed to establish the circumstances under which different salient comparisons are evoked.

Molecular mechanism of antifolate transport-deficiency in a methotrexate-resistant MOLT-3 human leukemia cell line

Ohnuma et al reported a series of methotrexate-resistant MOLT-3 human T-cell acute lymphoblastic leukemia cell lines that showed decreasing methotrexate (MTX) uptake as the sublines acquired increasing MTX resistance (Cancer Res 45:1815, 1985). The alteration of MTX uptake kinetics in these cells, the intermediately resistant MOLT-3/MTX200 and the highly resistant MOLT-3/MTX10,000 cell lines, was attributed to a change in Vmax for methotrexate transport, without an apparent change in affinity of the transporter for MTX. We studied these cell lines to determine whether alteration of transcription or translation of the recently isolated reduced folate carrier gene (RFC1) was the cause of MTX transport deficiency in these cell lines. Reconstitution of RFC activity in MOLT-3/MTX10,000 cells by transduction with a murine RFC retroviral vector reversed MTX resistance and trimetrexate sensitivity. Although RFC1 RNA levels were unchanged in the resistant cell lines, FACS analysis using a polyclonal anti-RFC1 antibody showed no detectable RFC1 protein in the MOLT-3/MTX10,000 cells. Determination of the nucleotide sequence of RFC1 genes from MOLT-3/MTX10,000 cells revealed that this cell line contained 3 RFC1 alleles: a wild-type allele, an allele containing the premature stop codon at codon 40 and a third allele containing another mutation, which resulted in a premature stop codon at codon 25. We examined the relative expression of these alleles by determining the nucleotide sequence of 24 RFC1 cDNA subclones from MOLT-3/MTX10,000 cells and found that only one-third of these clones contained the wild-type sequence. Determination of the genomic sequence of RFC1 in MOLT-3/ MTX200 cells demonstrated that these cells were heterozygous for a mutation at codon 40, but were homozygous for the wild-type sequence at codon 25. Thus, the acquisition of MTX transport-deficiency in MOLT-3/MTX10,000 cells results from inactivating mutations of RFC1 gene alleles.

Statistical modelling in specific case analysis

In spite of the problems associated with the development of a statistical approach in specific case analysis, the potential of two statistical methods, logistic regression and Bayesian belief networks, has been investigated and found encouraging in the context of a database relating to child murders with a sexual connotation. Continual collaboration between statisticians and detectives would be needed in the collection of the data, the choice and construction of the models, and the interpretation of the results.