Observation of WWγ Production and Search for Hγ Production in Proton-Proton Collisions at sqrt[s]=13 TeV

The observation of WWγ production in proton-proton collisions at a center-of-mass energy of 13 TeV with an integrated luminosity of 138  fb^{-1} is presented. The observed (expected) significance is 5.6 (5.1) standard deviations. Events are selected by requiring exactly two leptons (one electron and one muon) of opposite charge, moderate missing transverse momentum, and a photon. The measured fiducial cross section for WWγ is 5.9±0.8(stat)±0.8(syst)±0.7(modeling)  fb, in agreement with the next-to-leading order quantum chromodynamics prediction. The analysis is extended with a search for the associated production of the Higgs boson and a photon, which is generated by a coupling of the Higgs boson to light quarks. The result is used to constrain the Higgs boson couplings to light quarks.

New Structures in the J/ψJ/ψ Mass Spectrum in Proton-Proton Collisions at sqrt[s]=13 TeV

A search is reported for near-threshold structures in the J/ψJ/ψ invariant mass spectrum produced in proton-proton collisions at sqrt[s]=13  TeV from data collected by the CMS experiment, corresponding to an integrated luminosity of 135  fb^{-1}. Three structures are found, and a model with quantum interference among these structures provides a good description of the data. A new structure is observed with a local significance above 5 standard deviations at a mass of 6638_{-38}^{+43}(stat)_{-31}^{+16}(syst)  MeV. Another structure with even higher significance is found at a mass of 6847_{-28}^{+44}(stat)_{-20}^{+48}(syst)  MeV, which is consistent with the X(6900) resonance reported by the LHCb experiment and confirmed by the ATLAS experiment. Evidence for another new structure, with a local significance of 4.7 standard deviations, is found at a mass of 7134_{-25}^{+48}(stat)_{-15}^{+41}(syst)  MeV. Results are also reported for a model without interference, which does not fit the data as well and shows mass shifts up to 150 MeV relative to the model with interference.

Search for Scalar Leptoquarks Produced via τ-Lepton-Quark Scattering in pp Collisions at sqrt[s]=13 TeV

The first search for scalar leptoquarks produced in τ-lepton-quark collisions is presented. It is based on a set of proton-proton collision data recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138  fb^{-1}. The reconstructed final state consists of a jet, significant missing transverse momentum, and a τ lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark-τ-quark coupling strength.

Search for Inelastic Dark Matter in Events with Two Displaced Muons and Missing Transverse Momentum in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for dark matter in events with a displaced nonresonant muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138  fb^{-1} of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section σ(pp→A^{'}→χ_{1}χ_{2}) and the decay branching fraction B(χ_{2}→χ_{1}μ^{+}μ^{-}), where A^{'} is a dark photon and χ_{1} and χ_{2} are states in the dark sector with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter.

Probing Small Bjorken-x Nuclear Gluonic Structure via Coherent J/ψ Photoproduction in Ultraperipheral Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

Quasireal photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The coherent J/ψ photoproduction cross section in ultraperipheral lead-lead collisions is measured as a function of photon-nucleus center-of-mass energies per nucleon (W_{γN}^{Pb}) over a wide range of 40 Collapse

Key Words Collapse

MESH Headings Collapse

Grants Collapse

Observation of τ Lepton Pair Production in Ultraperipheral Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

We present an observation of photon-photon production of τ lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of 404  μb^{-1} collected by the CMS experiment at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV. The γγ→τ^{+}τ^{-} process is observed for τ^{+}τ^{-} events with a muon and three charged hadrons in the final state. The measured fiducial cross section is σ(γγ→τ^{+}τ^{-})=4.8±0.6(stat)±0.5(syst)  μb, where the second (third) term corresponds to the statistical (systematic) uncertainty in σ(γγ→τ^{+}τ^{-}) in agreement with leading-order QED predictions. Using σ(γγ→τ^{+}τ^{-}), we estimate a model-dependent value of the anomalous magnetic moment of the τ lepton of a_{τ}=0.001_{-0.089}^{+0.055}.

Measurement of the Dependence of the Hadron Production Fraction Ratios f_{s}/f_{u} and f_{d}/f_{u} on B Meson Kinematic Variables in Proton-Proton Collisions at sqrt[s]=13 TeV

The dependence of the ratio between the B_{s}^{0} and B^{+} hadron production fractions, f_{s}/f_{u}, on the transverse momentum (p_{T}) and rapidity of the B mesons is studied using the decay channels B_{s}^{0}→J/ψϕ and B^{+}→J/ψK^{+}. The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 61.6  fb^{-1}. The f_{s}/f_{u} ratio is observed to depend on the B p_{T} and to be consistent with becoming asymptotically constant at large p_{T}. No rapidity dependence is observed. The ratio of the B^{0} to B^{+} meson production fractions, f_{d}/f_{u}, is also measured, for the first time in proton-proton collisions, using the B^{0}→J/ψK^{*0} decay channel. The result is found to be within 1 standard deviation of unity and independent of p_{T} and rapidity, as expected from isospin invariance.

Search for Exotic Higgs Boson Decays H→AA→4γ with Events Containing Two Merged Diphotons in Proton-Proton Collisions at sqrt[s]=13 TeV

We present the first direct search for exotic Higgs boson decays H→AA, A→γγ in events with two photonlike objects. The hypothetical particle A is a low-mass spin-0 particle decaying promptly to a merged diphoton reconstructed as a single photonlike object. We analyze the data collected by the CMS experiment at sqrt[s]=13  TeV corresponding to an integrated luminosity of 136  fb^{-1}. No excess above the estimated background is found. We set upper limits on the branching fraction B(H→AA→4γ) of (0.9-3.3)×10^{-3} at 95% confidence level for masses of A in the range 0.1-1.2 GeV.

Observation of Same-Sign WW Production from Double Parton Scattering in Proton-Proton Collisions at sqrt[s]=13 TeV

The first observation of the production of W^{±}W^{±} bosons from double parton scattering processes using same-sign electron-muon and dimuon events in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 138  fb^{-1} recorded at a center-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. Multivariate discriminants are used to distinguish the signal process from the main backgrounds. A binned maximum likelihood fit is performed to extract the signal cross section. The measured cross section for production of same-sign W bosons decaying leptonically is 80.7±11.2(stat) _{-8.6}^{+9.5}(syst)±12.1(model)  fb, whereas the measured fiducial cross section is 6.28±0.81(stat)±0.69(syst)±0.37(model)  fb. The observed significance of the signal is 6.2 standard deviations above the background-only hypothesis.

Observation of the Rare Decay of the η Meson to Four Muons

A search for the rare η→μ^{+}μ^{-}μ^{+}μ^{-} double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers during 2017 and 2018 and corresponding to an integrated luminosity of 101  fb^{-1}. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the η→μ^{+}μ^{-} decay as normalization, the branching fraction B(η→μ^{+}μ^{-}μ^{+}μ^{-})=[5.0±0.8(stat)±0.7(syst)±0.7(B_{2μ})]×10^{-9} is measured, where the last term is the uncertainty in the normalization channel branching fraction. This work achieves an improved precision of over 5 orders of magnitude compared to previous results, leading to the first measurement of this branching fraction, which is found to agree with theoretical predictions.

Search for Higgs Boson Decay to a Charm Quark-Antiquark Pair in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for the standard model Higgs boson decaying to a charm quark-antiquark pair, H→cc[over ¯], produced in association with a leptonically decaying V (W or Z) boson is presented. The search is performed with proton-proton collisions at sqrt[s]=13  TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138  fb^{-1}. Novel charm jet identification and analysis methods using machine learning techniques are employed. The analysis is validated by searching for Z→cc[over ¯] in VZ events, leading to its first observation at a hadron collider with a significance of 5.7 standard deviations. The observed (expected) upper limit on σ(VH)B(H→cc[over ¯]) is 0.94 (0.50_{-0.15}^{+0.22})pb at 95% confidence level (C.L.), corresponding to 14 (7.6_{-2.3}^{+3.4}) times the standard model prediction. For the Higgs-charm Yukawa coupling modifier, κ_{c}, the observed (expected) 95% C.L. interval is 1.1<|κ_{c}|<5.5 (|κ_{c}|<3.4), the most stringent constraint to date.

Search for Nonresonant Pair Production of Highly Energetic Higgs Bosons Decaying to Bottom Quarks

A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138  fb^{-1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ_{2V}, excluding κ_{2V}=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.

Search for Higgs Boson and Observation of Z Boson through Their Decay into a Charm Quark-Antiquark Pair in Boosted Topologies in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for the standard model (SM) Higgs boson (H) produced with transverse momentum (p_{T}) greater than 450 GeV and decaying to a charm quark-antiquark (cc[over ¯]) pair is presented. The search is performed using proton-proton collision data collected at sqrt[s]=13  TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138  fb^{-1}. Boosted H→cc[over ¯] decay products are reconstructed as a single large-radius jet and identified using a deep neural network charm tagging technique. The method is validated by measuring the Z→cc[over ¯] decay process, which is observed in association with jets at high p_{T} for the first time with a signal strength of 1.00_{-0.14}^{+0.17}(syst)±0.08(theo)±0.06(stat), defined as the ratio of the observed process rate to the SM expectation. The observed (expected) upper limit on σ(H)B(H→cc[over ¯]) is set at 47 (39) times the SM prediction at 95% confidence level.

Probing Heavy Majorana Neutrinos and the Weinberg Operator through Vector Boson Fusion Processes in Proton-Proton Collisions at sqrt[s]=13 TeV

The first search exploiting the vector boson fusion process to probe heavy Majorana neutrinos and the Weinberg operator at the LHC is presented. The search is performed in the same-sign dimuon final state using a proton-proton collision dataset recorded at sqrt[s]=13  TeV, collected with the CMS detector and corresponding to a total integrated luminosity of 138  fb^{-1}. The results are found to agree with the predictions of the standard model. For heavy Majorana neutrinos, constraints on the squared mixing element between the muon and the heavy neutrino are derived in the heavy neutrino mass range 50 GeV-25 TeV; for masses above 650 GeV these are the most stringent constraints from searches at the LHC to date. A first test of the Weinberg operator at colliders provides an observed upper limit at 95% confidence level on the effective μμ Majorana neutrino mass of 10.8 GeV.

Search for Higgs Boson Pair Production in the Four b Quark Final State in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for pairs of Higgs bosons produced via gluon and vector boson fusion is presented, focusing on the four b quark final state. The data sample consists of proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, and corresponds to an integrated luminosity of 138  fb^{-1}. No deviation from the background-only hypothesis is observed. A 95% confidence level upper limit on the Higgs boson pair production cross section is observed at 3.9 times the standard model prediction for an expected value of 7.8. Constraints are also set on the modifiers of the Higgs field self-coupling, κ_{λ}, and of the coupling of two Higgs bosons to two vector bosons, κ_{2 V}. The observed (expected) allowed intervals at the 95% confidence level are -2.3<κ_{λ}<9.4 (-5.0<κ_{λ}<12.0) and -0.1<κ_{2 V}<2.2 (-0.4<κ_{2 V}<2.5). These are the most stringent observed constraints to date on the HH production cross section and on the κ_{2 V } coupling.

Search for Flavor-Changing Neutral Current Interactions of the Top Quark and Higgs Boson in Final States with Two Photons in Proton-Proton Collisions at sqrt[s]=13 TeV

Proton-proton interactions resulting in final states with two photons are studied in a search for the signature of flavor-changing neutral current interactions of top quarks (t) and Higgs bosons (H). The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 137  fb^{-1}. No significant excess above the background prediction is observed. Upper limits on the branching fractions (B) of the top quark decaying to a Higgs boson and an up (u) or charm (c) quark are derived through a binned fit to the diphoton invariant mass spectrum. The observed (expected) 95% confidence level upper limits are found to be 0.019% (0.031%) for B(t→Hu) and 0.073% (0.051%) for B(t→Hc). These are the strictest upper limits yet determined.

Search for Resonances Decaying to Three W Bosons in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for resonances decaying into a W boson and a radion, where the radion decays into two W bosons, is presented. The data analyzed correspond to an integrated luminosity of 138  fb^{-1} recorded in proton-proton collisions with the CMS detector at sqrt[s]=13  TeV. One isolated charged lepton is required, together with missing transverse momentum and one or two massive large-radius jets, containing the decay products of either two or one W bosons, respectively. No excess over the background estimation is observed. The results are combined with those from a complementary channel with an all-hadronic final state, described in an accompanying paper. Limits are set on parameters of an extended warped extra-dimensional model. These searches are the first of their kind at the LHC.

Probing Charm Quark Dynamics via Multiparticle Correlations in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

Multiparticle azimuthal correlations of prompt D^{0} mesons are measured in Pb-Pb collisions at a nucleon-nucleon center-of-mass energy of sqrt[s_{NN}]=5.02  TeV. For the first time, a four-particle cumulant method is used to extract the second Fourier coefficient of the azimuthal distribution (v_{2}) of D^{0} mesons as a function of event centrality and the D^{0} transverse momentum. The ratios of the four-particle v_{2} values to previously measured two-particle cumulant results provide direct experimental access to event-by-event fluctuations of charm quark azimuthal anisotropies. These ratios are also found to be comparable to those of inclusive charged particles in the event. However, hints of deviations are seen in the most central and peripheral collisions. To investigate the origin of flow fluctuations in the charm sector, these measurements are compared to a model implementing fluctuations of charm quark energy loss via collisional or radiative processes in the quark-gluon plasma. These models cannot quantitatively describe the data over the full transverse momentum and centrality ranges, although the calculations with collisional energy loss provide a better description of the data.

Observation of the B_{c}^{+} Meson in Pb-Pb and pp Collisions at sqrt[s_{NN}]=5.02 TeV and Measurement of its Nuclear Modification Factor

The B_{c}^{+} meson is observed for the first time in heavy ion collisions. Data from the CMS detector are used to study the production of the B_{c}^{+} meson in lead-lead (Pb-Pb) and proton-proton (pp) collisions at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV, via the B_{c}^{+}→(J/ψ→μ^{+}μ^{-})μ^{+}ν_{μ} decay. The B_{c}^{+} nuclear modification factor, derived from the Pb-Pb-to-pp ratio of production cross sections, is measured in two bins of the trimuon transverse momentum and of the Pb-Pb collision centrality. The B_{c}^{+} meson is shown to be less suppressed than quarkonia and most of the open heavy-flavor mesons, suggesting that effects of the hot and dense nuclear matter created in heavy ion collisions contribute to its production. This measurement sets forth a promising new probe of the interplay of suppression and enhancement mechanisms in the production of heavy-flavor mesons in the quark-gluon plasma.

Measurement of the Inclusive and Differential Higgs Boson Production Cross Sections in the Decay Mode to a Pair of τ Leptons in pp Collisions at sqrt[s]=13 TeV

Measurements of the inclusive and differential fiducial cross sections of the Higgs boson are presented, using the τ lepton decay channel. The differential cross sections are measured as functions of the Higgs boson transverse momentum, jet multiplicity, and transverse momentum of the leading jet in the event, if any. The analysis is performed using proton-proton collision data collected with the CMS detector at the LHC at a center-of-mass energy of 13  TeV and corresponding to an integrated luminosity of 138  fb^{-1}. These are the first differential measurements of the Higgs boson cross section in the final state of two τ leptons. In final states with a large jet multiplicity or with a Lorentz-boosted Higgs boson, these measurements constitute a significant improvement over measurements performed in other final states.

Search for Long-Lived Particles Decaying in the CMS End Cap Muon Detectors in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for long-lived particles (LLPs) produced in decays of standard model (SM) Higgs bosons is presented. The data sample consists of 137  fb^{-1} of proton-proton collisions at sqrt[s]=13  TeV, recorded at the LHC in 2016-2018. A novel technique is employed to reconstruct decays of LLPs in the end cap muon detectors. The search is sensitive to a broad range of LLP decay modes and to masses as low as a few GeV. No excess of events above the SM background is observed. The most stringent limits to date on the branching fraction of the Higgs boson to LLPs subsequently decaying to quarks and τ^{+}τ^{-} are found for proper decay lengths greater than 6, 20, and 40 m, for LLP masses of 7, 15, and 40 GeV, respectively.

Self-Limited Formation of Bowl-Shaped Nanopores for Directional DNA Translocation

Solid-state nanopores of on-demand dimensions and shape can facilitate desired sensor functions. However, reproducible fabrication of arrayed nanopores of predefined dimensions remains challenging despite numerous techniques explored. Here, bowl-shaped nanopores combining properties of ultrathin membrane and tapering geometry are manufactured using a self-limiting process developed on the basis of standard silicon technology. The upper opening of the bowl-nanopores is 60-120 nm in diameter, and the bottom orifice reaches sub-5 nm. Current-voltage characteristics of the fabricated bowl-nanopores display insignificant rectification indicating weak ionic selectivity, in accordance to numerical simulations showing minor differences in electric field and ionic velocity upon the reversal of bias voltages. Simulations reveal, concomitantly, high-momentum electroosmotic flow downward along the concave nanopore sidewall. Collisions between the left and right tributaries over the bottom orifice drive the electroosmotic flow both up into the nanopore and down out of the nanopore through the orifice. The resultant asymmetry in electrophoretic-electroosmotic force is considered the cause responsible for the experimentally observed strong directionality in λ-DNA translocation with larger amplitude, longer duration, and higher frequencies for the downward movements from the upper opening than the upward ones from the orifice. Thus, the resourceful silicon nanofabrication technology is shown to enable nanopore designs toward enriching sensor applications.

Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at sqrt[s]=5.02 TeV Using Leptonic Decays

The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302  pb^{-1}. Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as σ_{WW}=37.0_{-5.2}^{+5.5}(stat)_{-2.6}^{+2.7}(syst)  pb, σ_{WZ}=6.4_{-2.1}^{+2.5}(stat)_{-0.3}^{+0.5}(syst)  pb, and σ_{ZZ}=5.3_{-2.1}^{+2.5}(stat)_{-0.4}^{+0.5}(syst)  pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy.

Observation of a New Excited Beauty Strange Baryon Decaying to Ξ_{b}^{-}π^{+}π^{-}

The Ξ_{b}^{-}π^{+}π^{-} invariant mass spectrum is investigated with an event sample of proton-proton collisions at sqrt[s]=13  TeV, collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 140  fb^{-1}. The ground state Ξ_{b}^{-} is reconstructed via its decays to J/ψΞ^{-} and J/ψΛK^{-}. A narrow resonance, labeled Ξ_{b}(6100)^{-}, is observed at a Ξ_{b}^{-}π^{+}π^{-} invariant mass of 6100.3±0.2(stat)±0.1(syst)±0.6(Ξ_{b}^{-})  MeV, where the last uncertainty reflects the precision of the Ξ_{b}^{-} baryon mass. The upper limit on the Ξ_{b}(6100)^{-} natural width is determined to be 1.9  MeV at 95% confidence level. The low Ξ_{b}(6100)^{-} signal yield observed in data does not allow a measurement of the quantum numbers of the new state. However, following analogies with the established excited Ξ_{c} baryon states, the new Ξ_{b}(6100)^{-} resonance and its decay sequence are consistent with the orbitally excited Ξ_{b}^{-} baryon, with spin and parity quantum numbers J^{P}=3/2^{-}.

376 Factors Affecting Female Medical Student Interest in Surgery - A Nationwide Cross-Sectional Survey

Introduction

We aim to elucidate female student interest in Surgery and factors that are deterring students from considering a surgical career. With this information, we can evaluate if there are changes that can be made within medical education.

Method

A cross-sectional online survey was distributed via LimeSurvey to medical students across 33 UK medical schools. Our survey assessed student interest in a surgical career, personal experience on clinical placements, and what attracts or dissuades students from a surgical career.

Results

211 student responses were collected. 57% of students indicated an interest in Surgery. 55% of female and 63% of male students expressed surgical interest. 65.7% of second-year students indicated surgical interest, compared to 54.3% of students in final year; a 17.35% decrease. When asked, 88% of students believe there is disproportionate female to male surgeons.

Conclusions

Although our survey revealed that there is a healthy interest in Surgery, the number of women considering Surgery continues to dwindle throughout training, leading to massive discrepancy. It is paramount that there are both male and female mentors for students to visualise that there are no limitations for women in the field of Surgery.

Primary Amyloidosis

Introduction/Objective

Amyloid light chain (AL) results from the deposition of immunoglobulin light chain fragments, and can lead to dysfunction in multiple organs. Our patient was being investigated for unknown malignancy with high differential for plasma cell neoplasm for severe amyloidosis leading to renal failure, uncontrolled ascites and thickening of the skin. The patient died of progressive liver and renal failure. Our autopsy findings show severe amyloidosis deposition in spleen, heart, kidney and liver with no significant plasma cells in the bone marrow, the findings correlate with a rare condition of primary AL amyloidosis.

Methods

63 years old man with no past medical history presenting with progressive leg swelling with 15 pounds weight loss. He was admitted to another hospital a month ago. Patient was a smoker with a pack in 2-3 days for 38 years, occasional alcohol intake with no history of heavy alcohol use and no drug use. The patient worked as a chef and lived with his wife. Physical examination shows temporal wasting with cachecxia, had difficulty in staying upright and wanting to sleep when presented to the emergency department. Physical examination was significant for decreased breath sound bilaterally, more on left side, central weakness noted given difficultly sitting upright from laying down flat. Also, there were some lymphadenopathy in the jugular digastric region. Laboratory showed an increase elevation in alkaline phosphatase to the 1000s along with elevated LDL to 300s, nephrotic range proteinuria. Chest X-ray showed left pleural effusion and CT chest and abdomen showed slight hepatosplenomegaly with hypoattenuation and focal calcification. Autopsy finding indicated heavy spleen (260 grams) with a stiff and hard texture. Liver weighs in upper limit of normal (1660 grams) with a yellow firm surface. There is significant amyloid deposition in spleen. Also, moderate amyloid deposition was seen in all the organs including liver, kidney, heart and, also in the skin. No definite lesion was seen in the gross, nor cancer cells found in the microscopy examination. Bone marrow examination did not reveal plasma cells, ruling out the possibility of multiple myeloma or plasma cell dyscrasia.

Conclusion

This is a rare case of AL primary amyloidosis with aggressive progression and poor prognosis not associated with plasma cell neoplasm.

Case Report: Coexistence of Adenoid Cystic Carcinoma and Adenoid Basal Carcinoma in the Uterine Cervix

Introduction/Objective

Adenoid cystic carcinoma (ACC) and adenoid basal carcinoma (ABC) are very rare tumors, accounting for less than 1% of all cervical adenocarcinomas. ACC is an aggressive neoplasm and has poor prognosis while ABC has a favorable prognosis. Coexistence of ACC or ABC and squamous intraepithelial lesion/invasive squamous cell carcinoma in the uterine cervix has been reported in the literature; however, coexistence of ACC and ABC in the uterine cervix is very rare.

Methods

Case presentation: Here we present a case of coexistence ACC and ABC in a 66-year-old woman who suffered from heavy bloody vaginal discharge for one year with weight fluctuations. The cervical exam and CT scan showed a friable mass at the uterine cervix, measuring up to 5.5 cm, and cervical mass punch biopsy was performed. Histopathological examination of the specimen revealed an intact nonkeratinizing stratified squamous epithelium overlying proliferation of nests punctuated by small round spaces, resembling cribriform pattern in the stroma. The tumor cells were small and basaloid with hyperchromatic nuclei and scant cytoplasm. Palisading of tumor cells at the peripheral of the tumor nests were observed in some areas. Mitotic figures and necrosis were not seen.

Immunohistochemical stains were performed and showed two distinct patterns of ACC and ABC. ACC tumor cells were positive for CD117, focally positive for CAM5.2 and S100, and negative for p63. ABC tumor cells were positive for p63 and EMA and negative for CD117 and S100. Both ACC and ABC components were positive for p16, Sox 10, BCL-2 and vimentin and negative for CK7, p40, CEA and ER. PAS stain showed positive staining in the basement membrane-like material in ACC component. A final pathologic diagnosis of coexistence of ACC and ABC of the uterine cervix were made.

Conclusion

Literature review revealed that this was an exceedingly rare case of coexistence of ACC and ABC in the uterine cervix. It is extremely important to correctly diagnose ACC and ABC as there is very poor prognosis in the former and good prognosis in the latter.

In-situ characterization of ultrathin nickel silicides using 3D medium-energy ion scattering

Epitaxial ultrathin films are of utmost importance for state-of-the-art nanoelectronic devices, such as MOSFET transistors and non-volatile memories. At the same time, as the film thickness is reduced to a few nanometers, characterization of the materials is becoming challenging for commonly used methods. In this report, we demonstrate an approach for in-situ characterization of phase transitions of ultrathin nickel silicides using 3D medium-energy ion scattering. The technique provides simultaneously depth-resolved composition and real-space crystallography of the silicide films using a single sample and with a non-invasive probe. We show, for 10 nm Ni films on Si, that their composition follows a normal transition sequence, such as Ni-Ni2Si-NiSi. However, the transition process is significantly different for samples with initial Ni thickness of 3 nm. Depth-resolved crystallography shows that the Ni films transform from an as-deposited disordered layer to an epitaxial silicide layer at the temperature of ~290 °C, significantly lower than previously reported. The high depth resolution of the technique permits us to determine the composition of the ultrathin films to be 38% Ni and 62% Si.

Impact of Daptomycin Dose Exposure Alone or in Combination with β-Lactams or Rifampin against Vancomycin-Resistant Enterococci in an In Vitro Biofilm Model

Enterococcus faecium strains are commonly resistant to vancomycin and β-lactams. In addition, E. faecium often causes biofilm-associated infections and these infections are difficult to treat. In this context, we investigated the activity of dosing regimens using daptomycin (DAP) (8, 10, 12, and 14 mg/kg of body weight/day) alone and in combination with ceftaroline (CPT), ampicillin (AMP), ertapenem (ERT), and rifampin (RIF) against 2 clinical strains of biofilm-producing vancomycin-resistant Enterococcus faecium (VREfm), namely, strains S447 and HOU503, in an in vitro biofilm model. HOU503 harbors common LiaS and LiaR substitutions, whereas S447 lacks mutations associated with the LiaFSR pathway. MIC results demonstrated that both strains were susceptible to DAP and resistant to CPT, AMP, ERT, and RIF. The 168-h pharmacokinetic/pharmacodynamic (PK/PD) CDC biofilm reactor models (simulating human antibiotic exposures) were used with titanium and polyurethane coupons to evaluate the efficacy of antibiotic combinations. DAP 12 and 14 achieved bactericidal activity against S447 but lacked such effect against HOU503. Addition of ERT and RIF enhanced DAP activity, allowing DAP 8 and 10 plus ERT or RIF to produce bactericidal activity against both strains at 168 h. While DAP 8 and 10 plus CPT improved killing, they did not reach bactericidal reduction against S447. Combination of AMP, CPT, ERT, or RIF resulted in enhanced and bactericidal activity for DAP against HOU503 at 168 h. Our data provide further support for the use of combinations of DAP with AMP, ERT, CPT, and RIF in infections caused by biofilm producing VREfm. Further research involving DAP combinations against biofilm-producing enterococci is warranted.

Determination of the Efficacy of Preservation of Non-Eye Area Water-Miscible Cosmetic and Toiletry Formulations: Collaborative Study

A collaborative study was conducted to test a method developed to distinguish between adequately and inadequately preserved cosmetic formulations. Nineteen laboratories participated in the study. Samples tested included shampoos, hair conditioners, oil-in-water emulsions, and water-in-oil-emulsions. Triplicate samples of 4 adequately preserved and 4 inadequately preserved cosmetic products were tested by each collaborative laboratory. Results showed that all inadequately preserved shampoo and conditioner samples failed to meet the acceptance criteria for adequately preserved formulations. Of the 51 preserved samples, 49 shampoos and 48 conditioners met the criteria for adequate preservation. All samples of inadequately preserved water-in-oil emulsions and oil-in-water emulsions failed to meet the acceptance criteria, whereas all adequately preserved emulsion formulations met the acceptance criteria.

A virome from ornamental flowers in an Australian rural town

Samples of leaves exhibiting symptoms resembling those caused by virus infection were collected from ornamental street flowers in a rural town in Western Australia. Thirty-seven leaf samples were collected from plants of iris, tulip, lily, daffodil, stock and grape hyacinth. Shotgun sequencing of cDNA derived from leaf samples was done, and analysis showed that about 6% of the sequences obtained were of viral origin. Assembly of virus-like sequences revealed complete or partial genome sequences of 13 virus isolates representing 11 virus species. Eight of the isolates were of potyviruses, one was of a macluravirus, three were of potexviruses, and one was of a bunya-like virus. The complete genome of an isolate originally classified as ornithogalum mosaic virus was genetically divergent and differed in polyprotein cleavage motifs, and we propose that this isolate represents a distinct species. The implications of importing to Australia live plant propagules infected with viruses are discussed.

Abstract PD4-12: Use of 64Cu-DOTA-trastuzumab positron emission tomography (PET) to predict response to ado-trastuzumab emtansine (TDM1)

Background: We have demonstrated that 64Cu-DOTA trastuzumab is an effective PET imaging agent for HER2 positive breast cancer and are now seeking to evaluate the methodology for prediction of response and benefit to ado-trastuzumab emtansine (TDM1) in women with metastatic disease.

Methods: Patients with metastatic breast cancer were eligible if they had biopsy confirmed HER2 + disease, at least 1 site of metastasis 2.0 cm or larger outside the biopsy site, and were to receive TDM1 as therapy. Pretreatment staging included 18F-FDG/PET. Prior to injection of 64Cu-DOTA-trastuzumab, patients received 45 mg of cold trastuzumab to reduce liver uptake. PET-CT scans were obtained at 21-25 h and 47-48 h over fields of view chosen in reference to 18F-FDG scans. TDM1 was administered at a dose of 3.6 mg/kg every 3 weeks. Restaging 18F-FDG/PET was performed every 2 cycles, and response to therapy was determined by PERCIST criteria. The radiolabel uptake was measured in terms of maximum voxel standardized uptake value (SUVmax).

Results: Ten women enrolled on study and are evaluable for response; three continue on TDM1 for 22-40 months and four patients remained on treatment for at least 1 year. The median age was 54.5 years (48-83 years); seven received prior trastuzumab-containing chemotherapy 3 wks to 55 months prior to study entry. HER2 was positive by IHC in 5 and by FISH in 5 (3 were 2+ by IHC; 1 was 1+ and 1 indeterminate). Complete or partial metabolic response was observed in 5 patients. Patients had their average SUVmax on 64Cu-DOTA trastuzumab PET (aSUVmax) assessed in addition to individual assessments on up to 8 lesions on both Day1 and Day2. The mean aSUVmax was (6.3, 8.8) for responding patients and (4.4, 5.2) for non-responder (day1, day2). The difference between responders and non-responders on Day1 aSUVmax was marginally significant (p=0.06), but significant on Day2 (p=0.04). The three highest aSUVmax on both day1 and day2 were three of the four patients with PFS&gt;1 year. Data on the relationship of 64Cu-DOTA trastuzumab PET to IHC and FISH, and individual lesion SUVmax including evidence suggesting a potential threshold effect will be presented.

Conclusions: In women with biopsy confirmed HER2 positive metastatic disease, 64Cu-DOTA-trastuzumab PET imaging is predictive for response to TDM1.

Citation Format: Mortimer JE, Bading JR, Frankel P, Tumyan L, Tran TT, Rockne RC, Shively JE, Gidwaney N, Park J, Colcher DM. Use of 64Cu-DOTA-trastuzumab positron emission tomography (PET) to predict response to ado-trastuzumab emtansine (TDM1) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD4-12.

Efficient enrichment cloning of TAL effector genes from Xanthomonas

Many plant-pathogenic xanthomonads use a type III secretion system to translocate Transcription Activator-Like (TAL) effectors into eukaryotic host cells where they act as transcription factors. Target genes are induced upon binding of a TAL effector to double-stranded DNA in a sequence-specific manner. DNA binding is governed by a highly repetitive protein domain, which consists of an array of nearly identical repeats of ca. 102 base pairs. Many species and pathovars of Xanthomonas, including pathogens of rice, cereals, cassava, citrus and cotton, encode multiple TAL effectors in their genomes. Some of the TAL effectors have been shown to act as key pathogenicity factors, which induce the expression of susceptibility genes to the benefit of the pathogen. However, due to the repetitive character and the presence of multiple gene copies, high-throughput cloning of TAL effector genes remains a challenge. In order to isolate complete TAL effector gene repertoires, we developed an enrichment cloning strategy based on •genome-informed in silico optimization of restriction digestions,•selective restriction digestion of genomic DNA, and•size fractionation of DNA fragments. Our rapid, cheap and powerful method allows efficient cloning of TAL effector genes from xanthomonads, as demonstrated for two rice-pathogenic strains of Xanthomonas oryzae from Africa.

Impact of High-Level Daptomycin Resistance in the Streptococcus mitis Group on Virulence and Survivability during Daptomycin Treatment in Experimental Infective Endocarditis

Among the viridans group streptococci, the Streptococcus mitis group is the most common cause of infective endocarditis. These bacteria have a propensity to be β-lactam resistant, as well as to rapidly develop high-level and durable resistance to daptomycin (DAP). We compared a parental, daptomycin-susceptible (DAPs) S. mitis/S. oralis strain and its daptomycin-resistant (DAPr) variant in a model of experimental endocarditis in terms of (i) their relative fitness in multiple target organs in this model (vegetations, kidneys, spleen) when animals were challenged individually and in a coinfection strategy and (ii) their survivability during therapy with daptomycin-gentamicin (an in vitro combination synergistic against the parental strain). The DAPr variant was initially isolated from the cardiac vegetations of animals with experimental endocarditis caused by the parental DAPs strain following treatment with daptomycin. The parental strain and the DAPr variant were comparably virulent when animals were individually challenged. In contrast, in the coinfection model without daptomycin therapy, at both the 106- and 107-CFU/ml challenge inocula, the parental strain outcompeted the DAPr variant in all target organs, especially the kidneys and spleen. When the animals in the coinfection model of endocarditis were treated with DAP-gentamicin, the DAPs strain was completely eliminated, while the DAPr variant persisted in all target tissues. These data underscore that the acquisition of DAPr in S. mitis/S. oralis does come at an intrinsic fitness cost, although this resistance phenotype is completely protective against therapy with a potentially synergistic DAP regimen.

Obesity is independently associated with infection in hospitalised patients with end-stage liver disease

BACKGROUND

Infection is the most common cause of mortality in end-stage liver disease (ESLD). The impact of obesity on infection risk in ESLD is not established.

AIM

To characterise the impact of obesity on infection risk in ESLD.

METHODS

We evaluated the association between infection and obesity in patients with ESLD. Patients grouped as non-obese, obesity class I-II and obesity class III were studied using the Nationwide Inpatient Sample. Validated diagnostic code based algorithms were utilised to determine weight category and infections, including bacteraemia, skin/soft tissue infection, urinary tract infection (UTI), pneumonia/respiratory infection, Clostridium difficile infection (CDI) and spontaneous bacterial peritonitis (SBP). Risk factors for infection and mortality were assessed using multivariable logistic regression analysis.

RESULTS

Of 115 465 patients identified, 100 957 (87.5%) were non-obese and 14 508 (12.5%) were obese, with 9489 (8.2%) as obesity class I-II and 5019 (4.3%) as obesity class III. 37 117 patients (32.1%) had an infection diagnosis. Infection was most prevalent among obesity class III (44.0%), followed by obesity class I-II (38.9%) and then non-obese (31.9%). In multivariable modelling, class III obesity (OR = 1.41; 95% CI 1.32-1.51; P < 0.001), and class I-II obesity (OR = 1.08; 95% CI 1.01-1.15; P = 0.026) were associated with infection. Compared to non-obese patients, obese individuals had greater prevalence of bacteraemia, UTI, and skin/soft tissue infection as compared to non-obese patients.

CONCLUSIONS

Obesity is newly identified to be independently associated with infection in end-stage liver disease. The distribution of infection sites varies based on weight category.

Abstract P3-10-04: Prevalence of pain and barriers to pain management in breast cancer survivors in Vietnam

Introduction: Breast cancer-related pain significantly affects quality of life and is well-documented in developed countries. However, little is known about the extent of breast cancer-related pain in developing countries. A study at the National Cancer Institute of Vietnam reported that 44% of breast cancer patients experienced moderate to severe pain. However, this study did not include breast cancer survivors, and little is known about the prevalence of pain and its management in this patient population.

Objectives: Determine the prevalence of pain, adequacy of pain management, and barriers to care in breast cancer survivors in Vietnam.

Methods: We administered previously validated and published symptom assessment tools (the BPI and MDASI) to 160 unselected Vietnamese women diagnosed and treated for breast cancer in 2007. Here we present a preliminary description of the results for the first 40 breast cancer survivors enrolled in this study.

Results: The most frequently reported symptoms were pain (62.5%, with 40% reporting the pain as severe), memory loss (50%), numbness/tingling (50%), sleep disturbance (45%), and appetite loss (32.5%). Only 23% reported adequate symptom management, with the costs of treatment and the false belief that no treatments existed for the pain being frequently cited as barriers to care.

Discussion: Cancer-related pain is highly prevalent in breast cancer survivors treated at the largest cancer hospital in Vietnam. The majority of patients report inadequate management of pain, often attributable to costs and false beliefs regarding pain management. Initiatives aimed at patient education and improving accessibility to pain management could significantly improve the quality of life in this patient population.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-10-04.

Impaired neural transmission and synaptic plasticity in superior cervical ganglia from β-amyloid rat model of Alzheimer's disease

Basal synaptic transmission and activity-dependent synaptic plasticity were evaluated in superior cervical sympathetic ganglia (SCG) of amyloid-β rat model of Alzheimer's disease (Aβ rat) using electrophysiological and molecular techniques. Rats were administered Aβ peptides (a mixture of 1:1 Aβ1-40 and Aβ1-42) by chronic intracerebroventricular infusion via 14-day mini-osmotic pumps (300 pmol/day). Control rats received Aβ40-1 (inactive reverse peptide: 300 pmol/day). Ganglionic compound action potentials were recorded before (basal) and after repetitive stimulation. In isolated SCG, ganglionic long-term potentiation (gLTP) was generated by a brief train of stimuli (20Hz for 20s) and ganglionic long-term depression (gLTD) was produced with trains of paired pulses. The input/output (I/O) curves of ganglia from Aβ rats showed a marked downward shift along all stimulus intensities, compared to those of ganglia from control animals, indicating impaired basal synaptic transmission. In addition, repetitive stimulation induced robust gLTP and gLTD in ganglia isolated from control animals, but, the same protocols failed to induce gLTP or gLTD in ganglia from Aβ rats indicating impairment of activity-dependent synaptic plasticity in these animals. Western blotting of SCG homogenate from Aβ rats revealed reduction in the ratio of phosphorylated-/total-CaMKII and in calcineurin protein levels. Although other mechanisms could be involved, these changes in signaling molecules could represent an important molecular mechanism linked to the failure to express synaptic plasticity in Aβ rat ganglia. Results of the current study could explain some of the peripheral nervous system manifestations of Alzheimer's disease.

Tobacco and other factors have a negative impact on quality of life in hepatitis C patients

Hepatitis C virus (HCV) is known to adversely affect general, social, emotional and mental health domains. This study was designed to identify variables that may be associated with these measurable outcomes. We conducted a cross-sectional retrospective review of demographic and clinical data from 800 patients with HCV evaluated between January 1998 and November 2007. Data were collected using a standardized questionnaire filled out by the patients at the first encounter. Variables evaluated included fibrosis stages (i.e. FS0/1/2 vs FS3/4), demographics, comorbid health conditions, tobacco and alcohol use, high-risk social behaviours and laboratory data. Variables assessed were depression, fatigue, problems sleeping and loss of interest in sex. Statistical analysis was performed using univariate and multivariate logistic regression. Depression (29.3%) in our HCV study population was associated with female gender, tobacco use, hyperlipidemia, history of heavy alcohol use and intravenous drug use. Fatigue (44.6%) was associated with end-stage renal disease, past and current tobacco use and current alcohol use. Difficulty sleeping (13.8%) was associated with past and current tobacco use, current alcohol use and diabetes. Loss of interest in sex (7.7%) was associated with current tobacco use, multiple risk factors for HCV and age at time of evaluation. Fibrosis stage (FS) also had a significant positive association with alcohol use (OR 2.61; P = 0.003) and tobacco use (OR 2.00; P = 0.002). Smoking and alcohol use have a significant negative impact on the presence of depression, fatigue, difficulty sleeping and loss of interest in sex in HCV patients. Practitioners should be aware of these associations, particularly tobacco use, which significantly and negatively impacted every variable evaluated.

Acute nicotine treatment prevents REM sleep deprivation-induced learning and memory impairment in rat

Rapid eye movement (REM) sleep deprivation (SD) is implicated in impairment of spatial learning and memory and hippocampal long-term potentiation (LTP). An increase in nicotine consumption among habitual smokers and initiation of tobacco use by nonsmokers was observed during SD. Although nicotine treatment was reported to attenuate the impairment of learning and memory and LTP associated with several mental disorders, the effect of nicotine on SD-induced learning and memory impairment has not been studied. Modified multiple platform paradigm was used to induce SD for 24 or 48 h during which rats were injected with saline or nicotine (1 mg kg(-1) s.c.) twice a day. In the radial arm water maze (RAWM) task, 24- or 48-h SD significantly impaired learning and short-term memory. In addition, extracellular recordings from CA1 and dentate gyrus (DG) regions of the hippocampus in urethane anesthetized rats showed a significant impairment of LTP after 24- and 48-h SD. Treatment of normal rats with nicotine for 24 or 48 h did not enhance spatial learning and memory or affect magnitude of LTP in the CA1 and DG regions. However, concurrent, acute treatment of rats with nicotine significantly attenuated SD-induced impairment of learning and STM and prevented SD-induced impairment of LTP in the CA1 and DG regions. These results show that acute nicotine treatment prevented the deleterious effect of sleep loss on cognitive abilities and synaptic plasticity.

Screening for hepatitis B in chemotherapy patients: survey of current oncology practices

BACKGROUND

Hepatitis B virus (HBV) reactivation occurs in up to 78% of patients receiving cytotoxic chemotherapy for nonhepatic malignancies. Reactivation can lead to hepatic dysfunction, jaundice and fulminant hepatic failure. Current recommendations include screening patients at risk for HBV prior to immunosuppressive therapy and initiating antiviral prophylaxis in patients with chronic HBV.

AIM

To investigate current practice among oncologists regarding HBV screening and antiviral prophylaxis in candidates for chemotherapy.

METHODS

A survey was sent to American Medical Association registered oncologists assessing demographics and HBV screening practices. Statistical analysis was performed using Fisher's exact test.

RESULTS

In all, 265 responses were received. Office-based physicians were less likely to screen for HBV prior to chemotherapy (P < 0.001). Years in practice varied: 51% with <5 years, 29% with 5-15 years and 18% with >15 years, with no difference in screening practices between groups (P = N.S.). Responders screen for HBV as follows: never - 20%, only in the presence of abnormal liver biochemistries - 30%, risk factors or history of hepatitis - 38%. In patients with known HBV, 75% of oncologists refer to specialists, 7% initiate therapy, while 15% do not refer or initiate therapy, most of whom are in an office setting (P = 0.02).

CONCLUSIONS

Twenty per cent of oncologists never screen for HBV prior to initiating chemotherapy. Office-based physicians were less likely to screen, treat or refer to a specialist prior to chemotherapy. Greater education regarding risk of HBV reactivation is needed for clinicians treating patients with immunosuppressive therapies.

Sirolimus-induced hyperlipidaemia in liver transplant recipients is not dose-dependent

BACKGROUND

Sirolimus is a potent immunosuppressive medication that acts by inhibiting T-cell proliferation. It has been used in kidney transplantation because of its lack of nephrotoxicity. It is now being investigated in liver transplantation, but there are concerns about safety and long-term side effects such as dyslipidaemia. Hypertriglyceridaemia is a common adverse event seen with sirolimus use, and often does not respond to dose reduction or anti-lipemic drugs.

METHOD

We report six patients who have developed significant hyperlipidaemia while receiving sirolimus, in spite of therapeutic trough levels.

CONCLUSION

All six patients showed either resolution or improvement in lipid levels with discontinuation of sirolimus.

Conformational analysis of thiopeptides: free energy calculations on the effects of thio-substitutions on the conformational distributions of alanine dipeptides

When the oxygen atom in a peptide bond is replaced by a sulfur atom, the restriction in the available conformational space and the ability of thioamides to confer resistance to enzymatic degradation renders thioamides as potentially useful building blocks for drug design and protein engineering. The solvation free energy differences between conformers of the same dipeptide can be high. Yet, previous conformational studies, basing on the (phi, psi) conformational energy maps of thio-substituted dipeptides, neglected both explicit water interactions and free energy considerations. In this paper, the (phi, psi) conformational free energy maps are obtained by single umbrella sampling in an explicit water environment for both alanine dipeptide and the corresponding thioamide derivatives. The phi and psi angles for the minima in the relative energy maps calculated with dielectric of 80 are similar to the corresponding phi and psi angles in the relative free energy maps for both Ac-Ala-NHMe (Ac: acetyl; Ala: alanine) and Act-Alat-NHMe (Act: thio-acetyl; Alat: thio-alanine). However, some large differences between the relative energy and relative free energy of major minima indicate that the consideration of free energy is important in determination of the relative occupancy of particular minima. Free energy maps for both Ac-Ala-NHMe and Act-Alat-NHMe show that thio-substitution favors conformations where phi < 0 because of the deeper beta and alphaR minima. The changes in the position and relative stability of minima were explained in terms of the destabilization of the regions near phi = -120, 0 and 120, psi = 60, -60, 180, which correspond to the increased steric hindrance due to the bulkier sulfur atom.

[Treatment of perforated gastroduodenal ulcer by simple suture followed by Helicobacter pylori eradication]

AIMS OF THE STUDY

To determine the prevalence of Helicobacter pylori (HP) infection in Vietnam in case of perforated gastro-duodenal ulcer and to evaluate efficiency of medical treatment to obtain eradication of HP and ulcer healing.

PATIENTS AND METHODS

One hundred and eleven patients with perforated gastro-duodenal ulcer underwent surgical suture. HP infection was diagnosed by urease test and pathologic examination of peroperative antral biopsies, and by postoperative detection of HP-specific immunoglobulins G. HP infection was defined by positivity of at least one test. Medical treatment included omeprazole, clarithromycin, and amoxicillin for 7 days followed by omeprazole for 3 weeks for duodenal ulcer and 5 weeks for gastric ulcer. Follow-up endoscopy with biopsies was performed 4 to 6 weeks after treatment cessation.

RESULTS

Among 111 patients, 107 (96%) were infected by HP. The 4 patients non-infected by HP were treated by omeprazole alone and excluded from the study. Ulcer healed in 99 patients (93%). HP eradication was obtained in 102 patients (95%). The 8 patients with a non-healed ulcer and the 5 patients in whom HP eradication was not obtained at the first endoscopic control received additional medical treatment. Ultimately HP eradication and ulcer healing were obtained in all cases.

CONCLUSION

In a country in which prevalence of HP infection is high, acid-reduction surgery is unnecessary in case of perforated gastro-duodenal ulcer treated by simple surgical closure.

Analysis of intracellular didanosine triphosphate at sub-ppb level using LC-MS/MS

An analytical procedure has been developed for the analysis of intracellular didanosine triphosphate (ddATP). An electrospray ionization tandem mass spectrometer (ESI-MS) was interfaced to liquid chromatography (LC) using a mobile phase CH3OH/H2O (25/75) containing 1% formic acid for the analysis of the 5'-triphosphate metabolite of the antiviral didanosine. In this procedure, ddATP was extracted from CEM-T4 cells, isolated using an exchange anion solid phase extraction procedure, enzymatically dephosphorylated and then analyzed by LC-MS/MS within a 1 min run time. The influence of several parameters (electrospray ionization interface, acidic modifiers of the mobile phase) has been studied. A calibration curve was generated and the linear regression analysis yielded a regression coefficient (r(2)) greater than 0.999. Using LC-MS/MS detection in single reaction monitoring mode (SRM), the limit of quantitation of ddA in CEM-T4 cells was 0.02 ng ml(-1). Furthermore, this procedure could be used to perform simultaneous detection of five nucleoside reverse transcriptase inhibitors, such as AZT, 3TC, ddA, ddC and d4T and make LC-MS/MS a method of choice for Therapeutic Drug Monitoring (TDM) in a clinical environment.

Concerted action of the FasL/Fas and perforin/granzyme A and B pathways is mandatory for the development of early viral hepatitis but not for recovery from viral infection

Cytotoxic T lymphocytes (CTL) play a major role in the recovery from primary viral infections and the accompanying tissue injuries. However, it is unclear to what extent the two main cytolytic pathways, perforin-granzyme A and B exocytosis and Fas ligand (FasL)-Fas interaction, contribute to these processes. Here we have employed mouse strains with either spontaneous mutations or targeted gene defects in one or more components of either of the two cytolytic pathways to analyze the molecular basis of viral clearance and induction of hepatitis during lymphocytic choriomeningitis virus infection. Our results reveal that viral clearance is solely dependent on perforin but that virus-induced liver damage only occurs when both the FasL/Fas and the perforin pathways, including granzymes A and B, are simultaneously activated. The finding that development of hepatitis but not viral clearance is dependent on the concomitant activation of FasL-Fas and perforin-granzymes may be helpful in designing novel strategies to prevent hepatic failures during viral infections.

Synthesis, X-ray crystallographic structures of thio substituted N-acetyl N'-methylamide alanine and evaluation of sp sulfur parameters of the CFF91 force field

Acetyl thioalanine N-methyl (Ac-Alat-NHMe) and thioacetyl alanine N-methyl (Act-Ala-NHMe) were synthesized, crystallized and their X-ray diffraction structures determined for the first time. Both molecules adopted beta-sheet conformations and showed similar hydrogen bonding patterns with one molecular surface forming two oxo hydrogen bonds and the other forming two thio hydrogen bonds. The crystal structure data for the two thioamides provided a validation of the thioamide parameters for the newly derived CFF91 force field because the observed crystal (phi, psi) angles were situated in the global minimum regions of the theoretical (phi, psi) map predicted using the parameters. In addition, the parameters were further validated because conformational energy minimization of the crystal structure produced low deviations in unit cell dimensions, bond lengths, bond angles and torsional angles, and a 120-ps molecular dynamics simulation also gave a low deviation for the most probable N-H...S=C bond distance.

Mullerian inhibiting substance regulates NFkappaB signaling and growth of mammary epithelial cells in vivo

Müllerian inhibiting substance (MIS) inhibits breast cancer cell growth in vitro through interference with cell cycle progression and induction of apoptosis, a process associated with NFkappaB activation and up-regulation of one of its important target genes, IEX-1S (Segev, D. L., Ha, T., Tran, T. T., Kenneally, M., Harkin, P., Jung, M., MacLaughlin, D. T., Donahoe, P. K., and Maheswaran, S. (2000) J. Biol. Chem. 275, 28371-28379). Here we demonstrate that MIS activates the NFkappaB signaling cascade, induces IEX-1S mRNA, and inhibits the growth of MCF10A, an immortalized human breast epithelial cell line with characteristics of normal cells. In vivo, an inverse correlation was found to exist between various stages of mammary growth and MIS type II receptor expression. Receptor mRNA significantly diminished during puberty, when the ductal system branches and invades the adipose stroma and during the expansive growth at lactation, but it was up-regulated during involution, a time of regression and apoptosis. Peripartum variations in MIS type II receptor expression correlated with NFkappaB activation and IEX-1S mRNA expression. Administration of MIS to female mice induced NFkappaB DNA binding and IEX-1S mRNA expression in the breast. Furthermore, exposure to MIS in vivo increased apoptosis in the mouse mammary ductal epithelium. Thus, MIS may function as an endogenous hormonal regulator of NFkappaB signaling and growth in the breast.