Demystifying the Role of Radiation Dose Bath in Brain Injury Using Machine Learning

PURPOSE/OBJECTIVE(S)

It is well known that high-dose radiation results in brain injury, the long-term effects of low-dose radiation, however, is uncertain. The purpose of this study was to investigate the role of low-dose bath on MRI changes, on both clinical and micro-architectural levels, using machine learning and computational methods.

MATERIALS/METHODS

Six hundreds and fifty-six temporal lobe and 45 whole brain DVHs from patients treated for nasopharyngeal cancer (NPC) with IMRT or proton were included in this study. Temporal lobe injury (TLI) was defined as development of new T1 enhancement on MRI with or without surrounding T2 edema. Patients were divided randomly into train (50%) and test (50%) sets. Accuracy and AUC were used to evaluate the model performance. Minimum redundancy maximum relevance (MRMR) or SHAP algorithms was employed for feature selection. Support vector machine or random forest was used for classification. Automated cortical region segmentation using FreeSurfer v6 was performed in 33 patients with a minimum follow-up of 4 years. Architectural and biological MRI changes were determined in 34 different brain regions for each individual patient.

RESULTS

The top-ranked temporal lobe features predicting TLI were V66/V38 for IMRT patients and V10 for proton patients with an AUC of 0.95 and 0.74, respectively. For whole brain, the top features were V16 and V13 with an AUC of 0.70. The rates of TLI at 5 years for V10-20(whole brain) ≥ 180cc and V10-20(whole brain) < 180 were 39.5% and 6.2%, respectively (HR = 5.5, 95% CI 1.4-22.0, p = 0.02). There were global changes in gray matter thickness, with most pronounced changes occurred in parietal lobe (-4.79%, p = 0.007) and occipital lobe (-5.68%, p = 0.03). Similarly, there were diffuse changes in white matter and subcortical volume. After radiation, the frontal lobe increased by 17.5% (p = 0.04), lateral ventricle 41% (p = 0.03), and choroid plexus 34.3% (p = 0.03).

CONCLUSION

Low-dose radiation bath is associated with increased risk of temporal lobe injury and global disruption in brain architecture in NPC survivors.

A descriptive evaluation of resident prescription writing errors and self-perceived learning needs in dermatology

Prescribing errors in medical practice are common, and may be preventable in a significant proportion of cases. The literature on dermatological prescription errors is scarce. We sought to determine the rate and causes of resident prescribing errors in an outpatient dermatology practice, and surveyed residents' self-perceived prescription writing learning needs. All prescription errors were tabulated at the Ricky Kanee Schachter Dermatology Clinic (Women's College Hospital) from November 2019 to January 2020. There was an overall prescribing error rate of 1.58% (23/1457), with no significant difference between topical and systemic drugs (1.85% and 0.86%, respectively; P = 0.20) or between written prescriptions and those created by the electronic medical record (1.66% and 1.29%, respectively; P = 0.84). The survey response rate was 26.2% (22/82), with respondents reporting their overall confidence in dermatology prescription writing as (mean ± SD) 7.14 ± 1.75 out of 10. While the resident prescribing error rate was relatively low, multiple errors were avoidable, and residents agree that targeted dermatology-specific training in prescription writing is needed.

Long-Read RNA Sequencing Identifies Alternative Splice Variants in Hepatocellular Carcinoma and Tumor-Specific Isoforms

Alternative splicing (AS) allows generation of cell type-specific mRNA transcripts and contributes to hallmarks of cancer. Genome-wide analysis for AS in human hepatocellular carcinoma (HCC), however, is limited. We sought to obtain a comprehensive AS landscape in HCC and define tumor-associated variants. Single-molecule real-time long-read RNA sequencing was performed on patient-derived HCC cells, and presence of splice junctions was defined by SpliceMap-LSC-IDP algorithm. We obtained an all-inclusive map of annotated AS variants and further discovered 362 alternative spliced variants that are not previously reported in any database (neither RefSeq nor GENCODE). They were mostly derived from intron retention and early termination codon with an in-frame open reading frame in 81.5%. We corroborated many of these predicted unannotated and annotated variants to be tumor specific in an independent cohort of primary HCC tumors and matching nontumoral liver. Using the combined Sanger sequencing and TaqMan junction assays, unique and common expressions of spliced variants including enzyme regulators (ARHGEF2, SERPINH1), chromatin modifiers (DEK, CDK9, RBBP7), RNA-binding proteins (SRSF3, RBM27, MATR3, YBX1), and receptors (ADRM1, CD44v8-10, vitamin D receptor, ROR1) were determined in HCC tumors. We further focused functional investigations on ARHGEF2 variants (v1 and v3) that arise from the common amplified site chr.1q22 of HCC. Their biological significance underscores two major cancer hallmarks, namely cancer stemness and epithelial-to-mesenchymal transition-mediated cell invasion and migration, although v3 is consistently more potent than v1. Conclusion: Alternative isoforms and tumor-specific isoforms that arise from aberrant splicing are common during the liver tumorigenesis. Our results highlight insights gained from the analysis of AS in HCC.

The effects of global warming on allergic diseases

Global warming is a public health emergency. Substantial scientific evidence indicates an unequivocal rising trend in global surface temperature that has caused higher atmospheric levels of moisture retention leading to more frequent extreme weather conditions, shrinking ice volume, and gradually rising sea levels. The concomitant rise in the prevalence of allergic diseases is closely related to these environmental changes because warm and moist environments favour the proliferation of common allergens such as pollens, dust mites, molds, and fungi. Global warming also stresses ecosystems, further accelerating critical biodiversity loss. Excessive carbon dioxide, together with the warming of seawater, promotes ocean acidification and oxygen depletion. This results in a progressive decline of phytoplankton and fish growth that in turn promotes the formation of larger oceanic dead zones, disrupting the food chain and biodiversity. Poor environmental biodiversity and a reduction in the microbiome spectrum are risk factors for allergic diseases in human populations. While climate change and the existence of an allergy epidemic are closely linked according to robust international research, efforts to mitigate these have encountered strong resistance because of vested economic and political concerns in different countries. International collaboration to establish legally binding regulations should be mandatory for forest protection and energy saving. Lifestyle and behavioural changes should also be advocated at the individual level by focusing on low carbon living; avoiding food wastage; and implementing the 4Rs: reduce, reuse, recycle, and replace principles. These lifestyle measures are entirely consistent with the current recommendations for allergy prevention. Efforts to mitigate climate change, preserve biodiversity, and prevent chronic diseases are interdependent disciplines.

EBV-encoded miRNAs target ATM-mediated response in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a highly invasive epithelial malignancy that is prevalent in southern China and Southeast Asia. It is consistently associated with latent Epstein-Barr virus (EBV) infection. In NPC, miR-BARTs, the EBV-encoded miRNAs derived from BamH1-A rightward transcripts, are abundantly expressed and contribute to cancer development by targeting various cellular and viral genes. In this study, we establish a comprehensive transcriptional profile of EBV-encoded miRNAs in a panel of NPC patient-derived xenografts and an EBV-positive NPC cell line by small RNA sequencing. Among the 40 miR-BARTs, predominant expression of 22 miRNAs was consistently detected in these tumors. Among the abundantly expressed EBV-miRNAs, BART5-5p, BART7-3p, BART9-3p, and BART14-3p could negatively regulate the expression of a key DNA double-strand break (DSB) repair gene, ataxia telangiectasia mutated (ATM), by binding to multiple sites on its 3'-UTR. Notably, the expression of these four miR-BARTs represented more than 10% of all EBV-encoded miRNAs in tumor cells, while downregulation of ATM expression was commonly detected in all of our tested sequenced samples. In addition, downregulation of ATM was also observed in primary NPC tissues in both qRT-PCR (16 NP and 45 NPC cases) and immunohistochemical staining (35 NP and 46 NPC cases) analysis. Modulation of ATM expression by BART5-5p, BART7-3p, BART9-3p, and BART14-3p was demonstrated in the transient transfection assays. These findings suggest that EBV uses miRNA machinery as a key mechanism to control the ATM signaling pathway in NPC cells. By suppressing these endogenous miR-BARTs in EBV-positive NPC cells, we further demonstrated the novel function of miR-BARTs in inhibiting Zta-induced lytic reactivation. These findings imply that the four viral miRNAs work co-operatively to modulate ATM activity in response to DNA damage and to maintain viral latency, contributing to the tumorigenesis of NPC. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

An evidence-based approach to red blood cell transfusions in asymptomatically anaemic patients

INTRODUCTION

Surgeons and physicians encounter blood transfusions on a daily basis but a robust evidence-based strategy on indications and timing of transfusion in asymptomatic anaemic patients is yet to be determined. For judicious use of blood products, the risks inherent to packed red blood cells, the patient's co-morbidities and haemoglobin (Hb)/haematocrit levels should be considered. This review critiques and summarises the latest available evidence on the indications for transfusions in healthy and cardiac disease patients as well as the timing of transfusions relative to surgery.

METHODS

An electronic literature search of the MEDLINE(®), Google Scholar™ and Trip databases was conducted for articles published in English between January 2006 and January 2015. Studies discussing timing and indications of transfusion in medical and surgical patients were retrieved. Bibliographies of studies were checked for other pertinent articles that were missed by the initial search.

FINDINGS

Six level 1 studies (randomised controlled trials or systematic reviews) and six professional society guidelines were included in this review. In healthy patients without cardiac disease, a restrictive transfusion trigger of Hb 70-80g/l is safe and appropriate whereas in cardiac patients, the trigger is Hb 80-100g/l. The literature on timing of transfusions relative to surgery is limited. For the studies available, preoperative transfusions were associated with a decreased incidence of subsequent transfusions and timing of transfusions did not affect the rates of colorectal cancer recurrence.

Epigenetic silencing of GDF1 disrupts SMAD signaling to reinforce gastric cancer development

Accumulating evidence reveals the effectiveness of epigenetic therapy in gastric cancer. However, the molecular mechanisms and targets underlying such therapeutic responses remain elusive. Herein, we report an aberrant yet therapeutically rectifiable epigenetic signaling in gastric carcinogenesis. Administration of DNA-demethylating drug 5-aza-2'-deoxycytidine (5-aza-dC) reduced gastric cancer incidence by ~74% (P < 0.05) in N-nitroso-N-methylurea-treated mice. Through genome-wide methylation scanning, novel promoter hypermethylation-silenced and drug-targeted genes were identified in the resected murine stomach tumors and tissues. We uncovered that growth/differentiation factor 1 (Gdf1), a member of the transforming growth factor-β superfamily, was silenced by promoter hypermethylation in control tumor-bearing mice, but became reactivated in 5-aza-dC-treated mice (P < 0.05). In parallel, the downregulated SMAD2/3 phosphorylation in gastric cancer was revived by 5-aza-dC in vivo. Such hypermethylation-dependent silencing and 5-aza-dC-mediated reactivation of GDF1-SMAD2/3 activity was conserved in human gastric cancer cells (P < 0.05). Subsequent functional characterization further revealed the antiproliferative activity of GDF1, which was exerted through activation of SMAD2/3/4-mediated signaling, transcriptional controls on p15, p21 and c-Myc cell-cycle regulators and phosphorylation of retinoblastoma protein. Clinically, hypermethylation and loss of GDF1 was significantly associated with reduced phosphorylated-SMAD2/3 and poor survival in stomach cancer patients (P < 0.05). Taken together, we demonstrated a causal relationship between DNA methylation and a tumor-suppressive pathway in gastric cancer. Epigenetic silencing of GDF1 abrogates the growth-inhibitory SMAD signaling and renders proliferation advantage to gastric epithelial cells during carcinogenesis. This study lends support to epigenetic therapy for gastric cancer chemoprevention and identifies a potential biomarker for prognosis.

Reorganization of vascular care in Canada

The management of vascular disease requires knowledge of clinical assessment, pharmacotherapeutics, endovascular procedures and vascular surgery. In Canada, interventional cardiology, vascular surgery, interventional radiology and neurosurgery specialists may be involved in the care of patients with vascular disease, and they all claim to have expertise and an advantage in treating specific patients. The present article identifies the sources of the potential 'turf war' in vascular medicine, and proposes some possible solutions through reorganization of vascular care, with particular reference to the modern era of Canadian medicine.

Transgenic animals: current and alternative strategies

Transgenic animal technology is one of the most fascinating technologies developed in the last two decades. It allows us to address questions in life sciences that no other methods have achieved. The impact on biomedical and biological research, as well as commercial interests are overwhelming. The questions accompanying this fast growing technology and its diversified applications attract the attention from a variety of entities. Still, one of the most fundamental problems remaining is the search for an efficient and reliable gene delivery system for creating transgenic animals. The traditional method of pronuclear microinjection has displayed great variability in success among species. While an acceptable efficiency in the production of transgenic mice has been attained, the relative low efficiency (<1%) in creating transgenic livestock has become one of the barriers for its application. In the past decades, improvements in producing transgenic livestock have made a slow progression, however, the recent advancement in cloning technology and the ability to create transgenic livestock in a highly efficient manner, have opened the gate to a new era in transgenic technology. Discoveries of new gene delivery systems have created an enthusiastic atmosphere that has made this technology so unique. This review focuses on gene delivery strategies as well as various approaches that may assist the advancement of transgenic efficiency in large animals.

Inclusive double-pomeron exchange at the fermilab tevatron p p collider

We report results from a study of events with a double-Pomeron exchange topology produced in p p collisions at sqrt[s]=1800 GeV. The events are characterized by a leading antiproton and a large rapidity gap on the outgoing proton side. We find that the differential production cross section agrees in shape with predictions based on Regge theory and factorization, and that the ratio of double-Pomeron exchange to single diffractive production rates is relatively unsuppressed as compared to the O(10) suppression factor previously measured in single diffractive production.

Search for Kaluza-Klein graviton emission in pp collisions at square root[s] = 1.8 TeV using the missing energy signature

We report on a search for direct Kaluza-Klein graviton production in a data sample of 84 pb(-1) of ppmacr; collisions at sqrt[s]=1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and one or two high energy jets. We compare the data with the predictions from a (3+1+n)-dimensional Kaluza-Klein scenario in which gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for n=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71 TeV, respectively.

Search for pair production of scalar top quarks in R-parity violating decay modes in pp collisions at square root of s=1.8 TeV

We present the results of a search for pair production of scalar top quarks (t(1)) in an R-parity violating supersymmetry scenario in 106 pb(-1) of pp collisions at square root of s=1.8 TeV collected by the Collider Detector at Fermilab. In this mode each t(1) decays into a tau lepton and a b quark. We search for events with two tau's, one decaying leptonically (e or mu) and one decaying hadronically, and two jets. No candidate events pass our final selection criteria. We set a 95% confidence level lower limit on the t(1) mass at 122 GeV/c(2) for Br(t(1)-->tau b)=1.

Search for lepton flavor violating decays of a heavy neutral particle in p(-)p collisions at sqrt[s]=1.8 TeV

We report on a search for a high mass, narrow width particle that decays directly to emu, etau, or microtau. We use approximately 110 pb(-1) of data collected with the Collider Detector at Fermilab from 1992 to 1995. No evidence of lepton flavor violating decays is found. Limits are set on the production and decay of sneutrinos with R-parity violating interactions.

Central pseudorapidity gaps in events with a leading antiproton at the fermilab tevatron pp collider

We report a measurement of the fraction of events with a large pseudorapidity gap deltaeta within the pseudorapidity region available to the proton dissociation products X in p+p-->p+X. For a final state p of fractional momentum loss xi(p) and 4-momentum transfer squared t(p) within 0.06<xi(p)<0.09 and |t(p)|<1.0 [0.2] GeV2 at sqrt[s]=1800 [630] GeV, the fraction of events with deltaeta>3 is found to be 0.246+/-0.001 (stat)+/-0.042 (syst) [0.184+/-0.001 (stat)+/-0.043 (syst)]. Our results are compared with gap fractions measured in minimum bias pp collisions and with theoretical expectations.

Search for the supersymmetric partner of the top quark in dilepton events from pp collisions at square root of s=1.8 TeV

We have searched for pair production of the supersymmetric partner of the top quark (stop) in 107 pb(-1) of pp collisions at square root of s=1.8 TeV collected by the Collider Detector at Fermilab (CDF). Each stop is assumed to decay into a lepton, bottom quark, and supersymmetric neutrino. Such a scenario would give rise to events with two leptons, two hadronic jets, and a substantial imbalance of transverse energy. No evidence of such a stop signal has been found. We exclude stop masses in the region (80</=m(t)</=135 GeV/c(2)) in the mass plane of stop versus sneutrino.

Search for associated production of Upsilon and vector boson in pp collisions at sqrt[s]=1.8 TeV

We present a search for associated production of the Upsilon(1S) and a vector boson in 83 pb(-1) of ppmacr; collisions at sqrt[s]=1.8 TeV collected by the CDF experiment in 1994-1995. We find no evidence of the searched signal in the data, and set upper limits to the production cross sections.

Search for long-lived charged massive particles in pp collisions at square root s = 1.8 TeV

We report a search for the production of long-lived charged massive particles in a data sample of 90 pb(-1) of square root[s]=1.8 TeV pp collisions recorded by the Collider Detector at Fermilab. The search uses the muonlike penetration and anomalously high ionization energy loss signature expected for such a particle to discriminate it from backgrounds. The data are found to agree with background expectations, and cross section limits of O(1) pb are derived using two reference models, a stable quark and a stable scalar lepton.

Anti-inflammatory effects of high-dose montelukast in an animal model of acute asthma

BACKGROUND

Asthmatic inflammation is mediated by a network of cytokines, chemokines and adhesion molecules. Corticosteroids are the only effective agents available to control asthmatic inflammation. We investigated the effect of high-dose montelukast (MK), a selective cysteinyl leukotriene receptor 1 antagonist, on mediators of airway inflammation.

OBJECTIVE

The aim of this study was to determine the effect of a 3-day course of high-dose MK on mediators of airway inflammation induced by a single allergen challenge in sensitized mice.

METHODS

Ovalbumin (OVA)-sensitized BALB/c mice were treated with 25 mg/kg of MK or saline intravenously for 3 days. On the third day, a single inhalation challenge with OVA was given. Cellular infiltration was assessed in the bronchoalveolar lavage (BAL) and in the lung. Expression of IL-4, IL-5, IL-13 and eotaxin in the BAL, and the lung was determined. Serum IL-5 and total IgE was measured. IL-5 and eotaxin mRNA expression in the lung was determined. Finally, eotaxin and VACM-1 expression in the lung was assessed by immunohistochemistry.

RESULTS

MK reduced the number of eosinophils in the BAL by > 90%. There was also significant reduction in IL-5 in the BAL, lung and the serum, and IL-5 mRNA expression in the lung. IL-4 level in the lung and BAL, and IL-13 level in the lung also significantly decreased. Serum IgE level and lung VCAM-1 expression was also significantly lower in treated animals, but eotaxin protein and mRNA expression in the lung remained unchanged.

CONCLUSION

MK exerts its anti-inflammatory effect through the suppression of T helper type-2 (Th2) cytokines. The use of high-dose MK as an anti-inflammatory agent in acute asthma should be further explored.

Search for a W' boson decaying to a top and bottom quark pair in 1.8 TeV pp collisions

We report the results of a search for a W' boson produced in pp; collisions at a center-of-mass energy of 1.8 TeV using a 106 pb(-1) data sample recorded by the Collider Detector at Fermilab. We observe no significant excess of events above background for a W' boson decaying to a top and bottom quark pair. In a model where this boson would mediate interactions involving a massive right-handed neutrino (nu(R)) and have standard model strength couplings, we use these data to exclude a W' boson with mass between 225 and 536 GeV/c(2) at 95% confidence level for M(W')>>M(nu(R)) and between 225 and 566 GeV/c(2) at 95% confidence level for M(W')<M(nu(R)).

Limits on extra dimensions and new particle production in the exclusive photon and missing energy signature in pp collisions at square root [s]=1.8 TeV

The exclusive gammaE(T) signal has a small standard model cross section and is thus a channel sensitive to new physics. This signature is predicted by models with a superlight gravitino or with large extra spatial dimensions. We search for such signals at the Collider Detector at Fermilab, using 87 pb(-1) of data at square root [s]=1.8 TeV, and extract 95% C.L. limits on these processes. A limit of 221 GeV is set on the scale |F|(1/2) in supersymmetric models. For 4, 6, and 8 extra dimensions, model-dependent limits on the fundamental mass scale M(D) of 0.55, 0.58, and 0.60 TeV, respectively, are found. We also specify a "pseudo-model-independent" method of comparing the results to theoretical predictions.

Search for new physics in photon-lepton events in pp collisions at sqrt[s] = 1.8 TeV

We present the results of a search in pp collisions at sqrt[s] = 1.8 TeV for anomalous production of events containing a photon and a lepton (e or mu), both with large transverse energy, using 86 pb(-1) of data collected with the Collider Detector at Fermilab during the 1994-1995 collider run at the Fermilab Tevatron. The presence of large missing transverse energy (E(T)), additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large E(T), for which the observed total is 16 events and the expected mean total is 7.6+/-0.7 events.

Upsilon production and polarization in p p macro collisions at square root of s = 1.8 TeV

We report on measurements of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) differential cross sections (d(2)sigma/dp(T)dy)(/y/<0.4), as well as on the Upsilon(1S) polarization in p p macro collisions at square root of s = 1.8 TeV using a sample of 77+/-3 pb(-1) collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay Upsilon-->mu(+)mu(-). The measured angular distribution of the muons in the Upsilon(1S) rest frame is consistent with unpolarized meson production.

Diffractive dijet production at sqrt[s] = 630 and 1800 GeV at the Fermilab Tevatron

We report a measurement of the diffractive structure function F(D)(jj) of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in pp collisions at sqrt[s] = 630 GeV at the Fermilab Tevatron. The ratio of F(D)(jj) at sqrt[s] = 630 GeV to F(D)(jj) obtained from a similar measurement at sqrt[s] = 1800 GeV is compared with expectations from QCD factorization and other theoretical predictions. We also report a measurement of the xi ( x-Pomeron) and beta ( x of parton in Pomeron) dependence of F(D)(jj) at sqrt[s] = 1800 GeV. In the region 0.035<xi<0.095, /t/<1 GeV2, and beta<0.5, F(D)(jj)(beta,xi) is found to be of the form beta(-1.0+/-0.1)xi(-0.9+/-0.1), which obeys beta-xi factorization.

Search for new heavy particles in the WZ0 final state in pp collisions at square root[s] = 1.8 TeV

We present the first general search for new heavy particles, X, which decay via X --> WZ0 --> e(nu)+jj as a function of M(X) and Gamma(X) in pp collisions at square root[s] = 1.8 TeV. No evidence is found for production of X in 110 pb(-1) of data collected by the Collider Detector at Fermilab. General cross section limits are set at the 95% C.L. as a function of mass and width of the new particle. The results are further interpreted as mass limits on the production of new heavy charged vector bosons which decay via W' --> WZ0 in an extended gauge model as a function of the width, Gamma(W'), and mixing factor between the W' and the standard model W bosons.

Study of B0 --> J/psiK(*)0pi(+)pi(-) decays with the collider detector at Fermilab

We report a study of the decays B0 --> J/psiK(*)0pi(+)pi(-), which involve the creation of a uu or dd quark pair in addition to a b -->c(cs) decay. The data sample consists of 110 pb(-1) of pp collisions at square root[s] = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching fractions to be B(B0 --> J/psiK(*0)pi(+)pi(-)) = (6.6 +/- 1.9 +/- 1.1)x10(-4) and B(B0 --> J/psiK0pi(+)pi(-)) = (10.3 +/- 3.3 +/- 1.5)x10(-4). Evidence is seen for contributions from psi(2S)K(*)0, J/psiK0rho(0), J/psiK(*+)pi(-), and J/psiK1(1270).

Search for gluinos and scalar quarks in pp collisions at square root[s] = 1.8 TeV using the missing energy plus multijets signature

We have performed a search for gluinos (g) and scalar quarks (q) in a data sample of 84 pb(-1) of pp collisions at square root[s] = 1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and three or more jets, a characteristic signature in R-parity-conserving supersymmetric models. The analysis has been performed "blind," in that the inspection of the signal region is made only after the predictions from standard model backgrounds have been calculated. Comparing the data with predictions of constrained supersymmetric models, we exclude gluino masses below 195 GeV/c2 (95% C.L.), independent of the squark mass. For the case m(q) approximately m(g), gluino masses below 300 GeV/c2 are excluded.

Measurement of the strong coupling constant from inclusive jet production at the Tevatron pp collider

We report a measurement of the strong coupling constant, alpha(s)(MZ), extracted from inclusive jet production in pp collisions at square root[s] = 1800 GeV. The QCD prediction for the evolution of alpha(s) with jet transverse energy ET is tested over the range 40<ET<450 GeV using ET for the renormalization scale. The data show good agreement with QCD in the region below 250 GeV. The value of alpha(s) at the mass of the Z0 boson averaged over the range 40<ET<250 GeV is found to be alpha(s)(MZ) = 0.1178+/-0.0001(stat)+0.0081(-0.0095)(expt. syst). The associated theoretical uncertainties are mainly due to the choice of renormalization scale ((+6%)(-4%)) and input parton distribution functions (5%).

Search for gluinos and squarks using like-sign dileptons in pp macro collisions at square root of s = 1.8 TeV

We present results of the first search for like-sign dilepton ( e(+/-)e(+/-), e(+/-)mu(+/-), mu(+/-)mu(+/-)) events associated with multijets and large missing energy using 106 pb(-1) of data in pp macro collisions at square root of s = 1.8 TeV collected during 1992-1995 by the CDF experiment. Finding no events that pass our selection, we examine pair production of gluinos (tilde g) and squarks (tilde q) in a constrained framework of the minimal supersymmetric standard model. At tan beta = 2 and mu = -800 GeV/c(2), we set 95% confidence level limits of M(tilde g)>221 GeV/c(2) for M(tilde g) approximately M(tilde q), and M(tilde q)>168 GeV/c(2) for M(tilde q)>>M(tilde g), both with small variation as a function of mu.

Observation of diffractive J/psi production at the Fermilab Tevatron

We report the first observation of diffractive J/psi(--> mu+mu-) production in pp collisions at root square[s] = 1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum p(mu)T>2 GeV/c within the pseudorapidity region /eta/ < 1.0, the ratio of diffractive to total J/psi production rates is found to be R(J/psi) = [1.45 +/- 0.25]%. The ratio R(J/psi)(x) is presented as a function of x-Bjorken. By combining it with our previously measured corresponding ratio R(jj)(x) for diffractive dijet production, we extract a value of 0.59 +/- 0.15 for the gluon fraction of the diffractive structure function of the proton.

Search for quark-lepton compositeness and a heavy W' Boson using the enu channel in p p macro collisions at square root of [s] = 1.8 TeV

We present searches for quark-lepton compositeness and a heavy W' boson at high electron-neutrino transverse mass. We use approximately 110 pb(-1) of data collected in p p macro collisions at square root of [s] = 1.8 TeV by the CDF Collaboration during 1992-1995. The data are consistent with standard model expectations. Limits are set on the quark-lepton compositeness scale Lambda, the ratio of partial cross sections sigma(W'-->enu)/sigma(W-->enu), and the mass of a W' boson with standard model couplings. We exclude Lambda<2.81 TeV and a W' boson with mass below 754 GeV/c(2) at the 95% confidence level. Combining with our previously published limit obtained using the muon channel, we exclude a W' boson with mass below 786 GeV/c(2) at the 95% confidence level.

Different treatment outcomes of two intruded permanent incisors--a case report

Intrusive luxation involves the displacement of the tooth apically into the alveolar socket. This type of injury represents a very complex wound, involving disruption of the marginal gingival seal, alveolar bone, periodontal ligament fibers, cementum and the neuro-vascular supply to the pulp, which results in severely compromised healing and possible complications. The case presented is a report of a 60-year-old lady who fell and intruded her two maxillary central incisors. The healing outcomes of the two central incisors were markedly different from each other even though they sustained similar injuries.

Charged-particle multiplicity pp collisions at square root of (s) = 1.8 TeV

We report on a measurement of the mean charged-particle multiplicity of jets in dijet events with dijet masses in the range 80-630 GeV/c(2), produced at the Tevatron in pp collisions with square root (s) = 1.8 TeV and recorded by the Collider Detector at Fermilab. The data are fit to perturbative-QCD calculations carried out in the framework of the modified leading log approximation and the hypothesis of local parton-hadron duality. The fit yields values for two parameters in that framework: the ratio of parton multiplicities in gluon and quark jets, r identical withN(g-jet)(partons)/N(q-jet)(partons) = 1.7+/-0.3, and the ratio of the number of charged hadrons to the number of partons in a jet, K(charged)(LPHD) identical with N(charged)(hadrons)/N(partons) = 0.57+/-0.11.

Transgenic pigs produced using in vitro matured oocytes infected with a retroviral vector

Here we report the production of transgenic pigs that express enhanced green fluorescent protein (eGFP). Porcine oocytes were matured in vitro in a serum-free, chemically defined maturation medium, subsequently infected with a replication deficient pseudotyped retrovirus, fertilized and cultured in vitro before being transferred to a recipient female. Two litters were born from these embryo transfers; one pig from each litter was identified as transgenic and both expressed eGFP. From a tool in basic research to direct applications in production agriculture, domestic livestock capable of expressing foreign genes have many scientific applications.

Defining the role of abciximab for acute coronary syndromes: lessons from CADILLAC, ADMIRAL, GUSTO IV, GUSTO V, and TARGET

Acute coronary syndromes (ACS), including those associated with or without ST-segment elevation, share a common pathophysiology mediated by activated platelets and thrombin. It is becoming increasingly appreciated that reperfusion therapies using primary mechanical or pharmacologic strategies result in suboptimal reperfusion at the myocardial tissue level. Complete reperfusion of the coronary microvasculature has recently been shown to be an important predictor for survival following myocardial infarction. Abciximab has well-established clinical benefits in numerous interventional trials. Through its anti-platelet and anti-thrombotic activities, abciximab reduces thrombus formation and hence minimizes risk of thrombotic microvascular embolization and improves tissue-level reperfusion. Several recent landmark trials have evaluated the clinical efficacy of adjunctive abciximab during mechanical or pharmacologic reperfusion therapy in the setting of ACS. This article provides an update of the role of abciximab in the treatment for ACS based on the results of these clinical trials.

Double diffraction dissociation at the Fermilab Tevatron collider

We present results from a measurement of double diffraction dissociation in pp collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width Deltaeta(0)>3 (overlapping eta = 0) is found to be 4.43+/-0.02(stat)+/-1.18(syst) mb [ 3.42+/-0.01(stat)+/-1.09(syst) mb] at square root of (s) = 1800[630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.

Measurement of d sigma/dM and forward-backward charge asymmetry for high-mass Drell-Yan e(+)e(-) pairs from pp macro collisions at square root of s = 1.8 TeV

We report on a measurement of the mass dependence of the forward-backward charge asymmetry, A(FB), and production cross section d sigma/dM for e(+)e(-) pairs with mass M(ee)>40 GeV/c(2). The data sample consists of 108 pb(-1) of pp macro collisions at square root of s = 1.8 TeV taken by the Collider Detector at Fermilab during 1992-1995. The measured asymmetry and d sigma/dM are compared with the predictions of the standard model and a model with an extra Z' gauge boson.

Measurement of the top quark p(T) distribution

We have measured the p(T) distribution of top quarks that are pair produced in pp collisions at sqrt[s] = 1.8 TeV using a sample of tt decays in which we observe a single high- p(T) charged lepton, a neutrino, and four or more jets. We use a likelihood technique that corrects for the experimental bias introduced due to event reconstruction and detector resolution effects. The observed distribution is consistent with the standard model prediction. We use these data to place limits on the production of high- p(T) top quarks suggested in some models of anomalous top quark pair production.

In-stent restenosis: update on intracoronary radiotherapy

Stents eliminate vessel recoil and remodeling, two of the three major causes of restenosis after balloon angioplasty, but they promote the third cause, neointimal proliferation. Intracoronary radiotherapy at the time of successful repeat balloon angioplasty is proving effective in treating in-stent restenosis and lowering rates of recurrence. Current techniques and their safety and efficacy are discussed.

Natural recovery in a community-based sample of alcoholics: study design and descriptive data

The majority of alcoholics who recover do so without the benefit of treatment, yet little is known about these individuals and the factors associated with their success. A better understanding is needed of the self-initiated and maintained change processes ("natural recovery") associated with such recoveries. In the current study, initiated in 1997, we followed up alcoholics identified in four previous community surveys and conducted a brief physical examination and an in-depth interview assessing factors thought to be associated with "natural recovery" or entry into treatment. Here we present the study model, describe our sample of 83 "naturally recovered" and 138 "hazardous problem drinkers," and report factors associated with "natural recovery." During the period when their drinking was at its most problematic, those who naturally recovered had discussed their alcohol-use associated problems with fewer network members and had been advised to stop drinking or to drink less by fewer network members. In addition to older age, "natural recovery" was associated with marriage, lower levels of avoidant coping, higher self-esteem, social networks with members who drank less, and a history of less frequent drug use and lower frequencies of intoxication. Rates of "natural recovery'' may be increased by encouraging the development of these attributes in hazardous problem drinkers who do not already have them.

Unprotected left main coronary artery stenting for cardiac allograft vasculopathy

Cardiac allograft vasculopathy is the leading cause of death after the first year of transplantation. Treatment outcomes with medication, balloon angioplasty, bypass surgery, and retransplantation have been disappointing. We present our initial experience with stenting of the left main coronary artery in the setting of allograft vasculopathy.

The role of postradiotherapy neck dissection in supraglottic carcinoma

PURPOSE

To evaluate our policy of performing neck dissection based on regional response after definitive radiotherapy in patients with supraglottic carcinoma and to identify the prognostic factors in this group of patients.

METHODS AND MATERIALS

Between 1970 and 1995, 121 patients with node-positive squamous cell carcinoma of the supraglottic larynx were treated with definitive radiotherapy. Sixty-nine percent of patients presented with 1997 AJCC Stage IV disease. The N-stage distribution was N1, 49; N2, 62; and N3, 10. The median size of the lymph nodes was 3 cm (range, 0.5-8 cm). Forty-five patients received once-a-day treatment with a median total dose of 65 Gy (range, 58.0-70.8 Gy) in 1.8-2.0 Gy per fraction over 48 days, and 76 patients received split-course accelerated hyperfractionation with a median total dose of 67.2 Gy (range, 63.2-73.6 Gy) in 1.6 Gy twice a day over 43 days. Patients whose lymph nodes were not clinically detectable at 4-6 weeks after the completion of radiotherapy (complete response) were followed without any neck dissection. Patients with persistent neck adenopathy (partial response) underwent neck dissection whenever possible. Mean follow-up of the living patients was 6.5 years.

RESULTS

Regional response was related to the size of lymph nodes at presentation. Eighty-seven percent of patients with nodal size of 3 cm or less had a complete response, whereas 43% of patients with nodal size greater than 3 cm had a partial response. The rate of regional control at 3 years for all patients in the study was 66%. The 3-year ultimate regional control rate after salvage neck dissection was 75%. A relapse in both the primary and regional sites was the most common pattern of relapse, accounting for 39% of all the failures. Local failure was associated with subsequent regional relapse with a relative risk of 4.3. For patients with complete response in whom postradiotherapy neck dissection was withheld, the regional control rates were 75% and 86% for N1 and N2, respectively. The rate of isolated regional relapse in this group of patients was 7.5%. In multivariate analysis, significant favorable factors predictive for regional control were female gender, accelerated hyperfractionation, and complete response; whereas factors predictive for overall survival were Karnofsky Performance Scale score and regional response. The rate of Radiation Therapy Oncology Group (RTOG) Grade 2 or 3 neck fibrosis was 17% and 23% for patients with and without postradiotherapy neck dissection, respectively.

CONCLUSION

Isolated regional relapse is not common in patients with supraglottic carcinoma when a complete response is achieved at 4-6 weeks after definitive radiotherapy and postradiotherapy neck dissection is not performed. Female gender, accelerated hyperfractionation, and complete response are favorable predictors of regional control.

Search for neutral supersymmetric Higgs bosons in pp collisions at sqrt[s] = 1.8TeV

We present the results of a search for neutral Higgs bosons produced in association with b quarks in pp-->bb(phi)-->bbb final states with 91+/-7 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV recorded by the Collider Detector at Fermilab. We find no evidence of such a signal and the data are interpreted in the context of the neutral Higgs sector of the minimal supersymmetric extension of the standard model. With basic parameter choices for the supersymmetric scale and the stop-quark mixing, we derive 95% C.L. lower mass limits for neutral Higgs bosons for tan(beta) values in excess of 35.

Production of chi(c1) and chi(c2) in pp collisions at sqrt[S] = 1.8 TeV

We have measured the ratio of prompt production rates of the charmonium states chi(c1) and chi(c2) in 110 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV. The photon from their decay into J/psi(gamma) is reconstructed through conversion into e+e- pairs. The energy resolution this technique provides makes the resolution of the two states possible. We find the ratio of production cross sections sigma(chi(c2))/sigma(chi(c1)) = 0.96+/-0.27(stat)+/-0.11(syst) for events with pT(J/psi) > 4.0 GeV/c, /eta(J/psi)/ < 0.6, and pT(gamma) > 1.0 GeV/c.

First measurement of the ratio B(t --> Wb)/B(t --> Wq) and associated limit on the Cabibbo-Kobayashi-Maskawa element /V(tb)/

We present the first measurement of the ratio of branching fractions R identical withB(t-->Wb)/B(t-->Wq) from p_p collisions at sqrt[s] = 1.8 TeV. The data set corresponds to 109 pb(-1) of data recorded by the Collider Detector at Fermilab during the 1992-95 Tevatron run. We measure R = 0.94(+0.31)(-0.24)(stat+syst) or R>0.61 (0.56) at 90% (95)% C.L., in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element /V(tb)/ under the assumption of three generations and unitarity.

Lay knowledge of physical education teachers about the emergency management of dental trauma in Hong Kong

The purpose of this study was to investigate the knowledge of a group of physical education (PE) teachers about the emergency management of dental trauma in Hong Kong. A postal questionnaire was sent to PE teachers in 100 randomly selected secondary schools in Hong Kong. A total of 166 teachers from 65 schools responded. Results show that a majority of the respondents have received formal teaching training (98.8%). While all but one teacher had received formal first aid training, only eight of them recalled that they had received advice on the management of dental trauma. Concerning the management of tooth fracture, 118 respondents (71.1%) gave an appropriate answer. In contrast, only 29 teachers (17.5%) were able to indicate the appropriate management for an avulsed tooth. Over 60% (102) of the respondents indicated it was "very urgent" to seek professional assistance if a permanent tooth has been avulsed, but they had little knowledge of the correct procedures for replanting or transporting avulsed teeth. Only 15 respondents (9%) pointed out that milk was the medium of choice for transporting avulsed teeth. Finally, over 90% (157) of respondents indicated that they had never received advice on the emergency procedures for the management of dental avulsion. The present study showed that the level of lay knowledge of management of dental injuries in a selection of PE teachers in Hong Kong is inadequate and educational campaigns are necessary to improve their emergency management of dental injuries.