274 research outputs found
Frozen section evaluation of lymph nodes in Oral squamous cell carcinoma: a retrospective study
The principal indication of performing a frozen section is to obtain a definite immediate diagnosis, on the basis of
which a surgical decision will be made. Immediate diagnosis allows the surgeon to proceed with further therapy
without any delay. A definite immediate diagnosis is said to be dependent on the reliability of frozen sections.
Many authors have carried out frozen section study on soft tissue tumors and lymph node evaluation in different
parts of the body with varying percentages of reliability. However, it appears that lymph node evaluations specifically in oral squamous cell carcinoma cases were not performed, or limited. Hence the present study was undertaken
to determine the reliability of frozen section diagnosis in the lymph nodes of oral squamous cell carcinomas. This
study was performed so that the surgeons would have an intraoperative assessment of the extent of local metastasis
and to determine the adequacy of resection before the wound is closed.
The objectives of the present study are to assess microscopically the frozen section of the palpable and non palpable
lymph nodes of neck for metastasis in patients with squamous cell carcinoma of oral cavity. To compare the micros-
copic features of paraffin embedded lymph node sections with those of frozen sections. To assess the reliability of
frozen section evaluation of cervical lymph nodes in oral squamous cell carcinoma.
The present research work gives 100% accuracy of frozen sections with due care by additional staining to frozen
sections by phloxine methylene blue stain, however cannot be in any way superior to the magnetic resonance imaging, computed tomography, immunoscintigraphy and lymphangioscintigraphy
Antagonistic effects of transforming growth factor-beta on vitamin D3 enhancement of osteocalcin and osteopontin transcription: reduced interactions of vitamin D receptor/retinoid X receptor complexes with vitamin E response elements
Osteocalcin and osteopontin are noncollagenous proteins secreted by
osteoblasts and regulated by a complex interplay of systemic and locally
produced factors, including growth factors and steroid hormones. We
investigated the mechanism by which transforming growth factor-beta (TGF
beta) inhibits 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3)-enhanced expression
of the osteocalcin (OC) and osteopontin (OP) genes. ROS 17/2.8 cells, in
which both genes are expressed, were transfected with reporter constructs
driven by native (i.e. wild-type) rat OC and mouse OP promoters. TGF beta
abrogated the 1,25-(OH)2D3 enhanced transcription of both the OC and OP
genes. The inhibitory TGF beta response for each requires vitamin D
response element (VDRE) sequences, although there are additional
contributions from proximal basal regulatory elements. These
transcriptional effects were further investigated for contribution of the
trans-activating factors, which interact with OC and OP VDREs, involving
the vitamin D receptor (VDR) and retinoid X receptor (RXR). Gel mobility
shift assays show that TGF beta significantly reduces induction of the
heterodimers VDR/RXR complexes in 1,25-(OH)2D3-treated ROS 17/2.8 cells.
However, Western blot and ligand binding analysis reveal that TGF beta
does not affect nuclear availability of the VDR. We also show that
activator protein-1 activity is up-regulated by TGF beta; thus, activator
protein-1 binding sites in the OC promoter may potentially contribute to
inhibitory effects of TGF beta on basal transcription. Our studies
demonstrate that the inhibitory action of TGF beta on the 1,25-(OH)2D3
enhancement of OC and OP transcription in osteoblastic cells results from
modulations of protein-DNA interactions at the OC and OP VDRE, which
cannot be accounted for by changes in VDR protein levels. As OC and OP
participate in bone turnover, our results provide insight into the
contributions of TGF beta and 1,25-(OH)2D3 to VDR-mediated gene regulatory
mechanism operative in bone formation and/or resorption events
Search for Higgs bosons decaying to tautau pairs in ppbar collisions at sqrt(s) = 1.96 TeV
We present a search for the production of neutral Higgs bosons decaying into
tautau pairs in ppbar collisions at a center-of-mass energy of 1.96 TeV. The
data, corresponding to an integrated luminosity of 5.4 fb-1, were collected by
the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the
95% C.L. on the product of production cross section and branching ratio for a
scalar resonance decaying into tautau pairs, and we then interpret these limits
as limits on the production of Higgs bosons in the minimal supersymmetric
standard model (MSSM) and as constraints in the MSSM parameter space.Comment: 7 pages, 5 figures, submitted to PL
Measurement of three-jet differential cross sections d sigma-3jet / d M-3jet in p anti-p collisions at sqrt(s)=1.96 TeV
We present the first measurement of the inclusive three-jet differential
cross section as a function of the invariant mass of the three jets with the
largest transverse momenta in an event in p anti-p collisions at sqrt(s) = 1.96
TeV. The measurement is made in different rapidity regions and for different
jet transverse momentum requirements and is based on a data set corresponding
to an integrated luminosity of 0.7 fb^{-1} collected with the D0 detector at
the Fermilab Tevatron Collider. The results are used to test the three-jet
matrix elements in perturbative QCD calculations at next-to-leading order in
the strong coupling constant. The data allow discrimination between
parametrizations of the parton distribution functions of the proton.Comment: 10 pages, 4 figures, 2 tables, submitted to Phys. Lett. B, corrected
chi2 values for NNPD
Search for pair production of the scalar top quark in muon+tau final states
We present a search for the pair production of scalar top quarks
(), the lightest supersymmetric partners of the top quarks, in
collisions at a center-of-mass energy of 1.96 TeV, using data
corresponding to an integrated luminosity of {7.3 } collected with the
\dzero experiment at the Fermilab Tevatron Collider. Each scalar top quark is
assumed to decay into a quark, a charged lepton, and a scalar neutrino
(). We investigate final states arising from and
. With no significant excess of events observed above the
background expected from the standard model, we set exclusion limits on this
production process in the (,) plane.Comment: Submitted to Phys. Lett.
Measurements of inclusive W+jets production rates as a function of jet transverse momentum in ppbar collisions at sqrt{s}=1.96 TeV
This Letter describes measurements of inclusive W (--> e nu) + n jet cross
sections (n = 1-4), presented as total inclusive cross sections and
differentially in the nth jet transverse momentum. The measurements are made
using data corresponding to an integrated luminosity of 4.2 fb-1 collected by
the D0 detector at the Fermilab Tevatron Collider, and achieve considerably
smaller uncertainties on W +jets production cross sections than previous
measurements. The measurements are compared to next-to-leading order
perturbative QCD (pQCD) calculations in the n =1-3 jet multiplicity bins and to
leading order pQCD calculations in the 4-jet bin. The measurements are
generally in agreement with pQCD predictions, although certain regions of phase
space are identified where the calculations could be improved
Measurement of spin correlation in ttbar production using dilepton final states
We measure the correlation between the spin of the top quark and the spin of
the anti-top quark in (ttbar -> W+ W- b bbar -> l+ nu b l- nubar bbar) final
states produced in ppbar collisions at a center of mass energy sqrt(s)=1.96
TeV, where l is an electron or muon. The data correspond to an integrated
luminosity of 5.4 fb-1 and were collected with the D0 detector at the Fermilab
Tevatron collider. The correlation is extracted from the angles of the two
leptons in the t and tbar rest frames, yielding a correlation strength C=
0.10^{+0.45}_{-0.45}, in agreement with the NLO QCD prediction within two
standard deviations, but also in agreement with the no correlation hypothesis.Comment: 10 pages, 3 figures, submitted to PL
Measurement of the ttbar production cross section using dilepton events in ppbar collisions
We present a measurement of the ttbar production cross section sigma(ttbar)
in ppbar collisions at sqrt{s} = 1.96 TeV using 5.4 fb-1 of integrated
luminosity collected with the D0 detector. We consider final states with at
least two jets and two leptons (ee, emu, mumu), and events with one jet for the
the emu final state as well. The measured cross section is sigma(ttbar)= 7.36
+0.90-0.79 (stat + syst) pb. This result combined with the cross section
measurement in the lepton + jets final state yields sigma(ttbar)=7.56
+0.63-0.56 (stat + syst) pb, which agrees with the standard model expectation.
The relative precision of 8% of this measurement is comparable to the latest
theoretical calculations.Comment: 9 pages, published in Phys. Lett.
Search for single top quarks in the tau+jets channel using 4.8 fb of collision data
We present the first direct search for single top quark production using tau
leptons. The search is based on 4.8 fb of integrated luminosity
collected in collisions at =1.96 TeV with the D0 detector
at the Fermilab Tevatron Collider. We select events with a final state
including an isolated tau lepton, missing transverse energy, two or three jets,
one or two of them tagged. We use a multivariate technique to discriminate
signal from background. The number of events observed in data in this final
state is consistent with the signal plus background expectation. We set in the
tau+jets channel an upper limit on the single top quark cross section of
\TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected
sensitivity for the observation of single top production when combining it with
electron+jets and muon+jets channels already published by the D0 collaboration
with 2.3 fb of data. We measure a combined cross section of
\SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure
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