Biomedical subjects

S Desai

Publications and source records attributed to S Desai.

At least 37 records · Page 2Linked to original sources

PubMed2002

Search for leptoquark pairs decaying into nunu+jets in pp collisions at square root[s] = 1.8 TeV.

We present the results of a search for leptoquark (LQ) pairs in (85.2+/-3.7) pb(-1) of pp* collider data collected by the D0 experiment at the Fermilab Tevatron. We observe no evidence for leptoquark production and set a limit on sigma(pp*-->LQLQ-->nunu+jets) as a function of the mass of the leptoquark (m(LQ)). Assuming the decay LQ-->nuq, we exclude scalar leptoquarks for m(LQ) < 98 GeV/c(2), and vector leptoquarks for m(LQ) < 200 GeV/c(2) and coupling which produces the minimum cross section, at a 95% confidence level.

Journal Article↗

PubMed2002

Search for the scalar top quark in pp collisions at square root[s] = 1.8 TeV.

We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of pp events corresponding to 108.3 pb(-1) of data collected with the D0 detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the sneutrino is the lightest supersymmetric particle. For the dominant decays of the lightest stop, t-->b chi+1 and t-->blnu, no evidence for signal is found. We derive cross-section limits as a function of stop ( t ), chargino ( chi+1), and sneutrino ( nu) masses.

Journal Article↗

PubMed2002

Direct search for charged higgs bosons in decays of top quarks.

We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large.

Journal Article↗

PubMed2002

Unrelated donor BMT recipients given pretransplant low-dose antithymocyte globulin have outcomes equivalent to matched sibling BMT: a matched pair analysis.

Fifty-seven patients receiving unrelated donor (UD) BMT were matched for disease and stage with 57 recipients of genotypically matched related donor (MRD) BMT. All UD recipients were matched serologically for A and B and by high resolution for DR and DQ antigens. All patients received CsA and 'short course' methotrexate with folinic acid. Unrelated donor BMT patients also received thymoglobulin 4.5 mg/kg (6 mg/kg if <30 kg) in divided doses over 3 days pretransplant. For UD and RD BMT, respectively, incidence of acute GVHD grade II-IV was 19 +/- 6% vs 36 +/- 8%, grade III-IV 10 +/- 6% vs 18 +/- 7%, chronic GVHD 44 +/- 8% vs 51 +/- 8%, non-relapse mortality 15 +/- 5% vs 8 +/- 4% at 100 days, 28 +/- 8% vs 36 +/- 7% at 3 years. At 3 years, relapse was 45 +/- 7% vs 42 +/- 7%, and disease-free survival 39 +/- 7% vs 37 +/- 7%. None of these differences are significant. Three-year overall survival was identical at 42 +/- 7%. For 29 patients with low/intermediate risk leukemia, disease-free survival was 68 +/- 10% after UD BMT vs 59 +/- 9% for RD BMT recipients (P = NS). Corresponding figures for high risk patients were 14 +/- 7% and 21 +/- 8%, respectively. We conclude that UD BMT recipients matched as above and given pretransplant ATG have similar outcomes to recipients of MRD BMT using conventional drug prophylaxis. Unrelated donor BMT should be considered in any circumstance where MRD BMT is routine.

Antilymphocyte Serum↗

PubMed2002

The venoneuroadipofascial pedicled distally based sural island myofasciocutaneous and muscle flaps: anatomical basis of a new concept.

Reconstruction of soft-tissue defects of the lower third of the leg, the heel and the foot remains a challenge. The distally based sural neurocutaneous flap has been used effectively to resurface these defects. However, the paucity of bulk in this flap makes it inadequate for complex post-traumatic or post-ablative soft-tissue reconstruction. We dissected 20 freshly amputated lower limbs after injecting them with a mixture of lead oxide and gelatin. We found muscular branches of the accompanying artery of the sural nerve to the gastrocnemius muscle in all 20 limbs. This led us to conceptualise the distally based venoneuroadipofascial pedicled island sural myofasciocutaneous and muscle flaps. These flaps are useful for the reconstruction of complex soft-tissue defects of the lower third of the leg, the heel and the foot.

Arteries↗

PubMed2001

Ratio of isolated photon cross sections in pp macro collisions at square root of s = 630 and 1800 GeV.

The inclusive cross section for production of isolated photons has been measured in pp macro collisions at square root of s = 630 GeV with the D0 detector at the Fermilab Tevatron Collider. The photons span a transverse energy (E(T)) range from 7-49 GeV and have pseudorapidity absolute value of eta < 2.5. This measurement is combined with the previous D0 result at square root of s = 1800 GeV to form a ratio of the cross sections. Comparison of next-to-leading-order QCD with the measured cross section at 630 GeV and the ratio of cross sections show satisfactory agreement in most of the E(T) range.

Journal Article↗

PubMed2001

Search for new physics using QUAERO: a general interface to D0 event data.

We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ, and t t macro production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W'-->WZ. Through this interface, we make three data sets collected by the D0 experiment at square root of [s] = 1.8 TeV publicly available.

Journal Article↗

PubMed2001

The role of leukocyte function-associated antigen-1 in animal models of inflammation.

Both preclinical and clinical data have identified leukocyte function-associated antigen-1 (LFA-1) as an important component of inflammatory disease states. We evaluated small molecule inhibitors of this glycoprotein in several animal models in which the inflammatory process is dependent on human or non-human primate LFA-1. (R)-5(4-bromobenzyl)-3(3,5-dichlorophenyl)-1,5-dimethylimidazolidine-2,4-dione, BIRT 377, effectively suppressed the production of human immunoglobulin (IgG) following reconstitution of severe combined immunodeficient (SCID) mice with human peripheral blood mononuclear cells. The BIRT 377 analog, BIX 642, inhibited the cellular infiltrate and increase in skin thickness associated with the delayed-type hypersensitivity reaction in previously immunized squirrel monkeys challenged with antigen. BIX 642 also inhibited the trans-vivo delayed-type hypersensitivity response in the footpads of SCID mice injected with human peripheral blood mononuclear cells and donor-sensitive antigen. These results demonstrate the efficacy of small molecule inhibitors of LFA-1 in preclinical models of inflammation dependent on human or non-human primate LFA-1.

Animals↗

PubMed2001

Direct immunodetection of antigens within the precast polyacrylamide gel.

Detection of specific proteins separated by SDS-PAGE is the basis for studying specific antigens. Immunodetection of antigens is commonly performed using Western blotting technique. In this paper we have shown that it is possible to eliminate Western blotting and to detect the antigens directly within the precast polyacrylamide gels by pretreating the gels with 50% isopropanol followed by distilled water treatment. This method would be valuable for large or difficult to transfer proteins.

2-Propanol↗

PubMed2001

Search for heavy particles decaying into electron-positron pairs in pp collisions.

We present results of searches for technirho (rho(T)), techniomega (omega(T)), and Z' particles, using the decay channels rho(T),omega(T),Z'-->e(+)e(-). The search is based on 124.8 pb(-1) of data collected by the D0 detector at the Fermilab Tevatron during 1992-1996. In the absence of a signal, we set 95% C.L. upper limits on the cross sections for the processes pp-->rho(T),omega(T),Z'-->e(+)e(-) as a function of the mass of the decaying particle. For certain model parameters, we exclude the existence of degenerate rho(T) and omega(T) states with masses below about 200 GeV. We exclude a Z' with mass below 670 GeV, assuming that it has the same couplings to fermions as the Z boson.

Journal Article↗

PubMed2001

Agonist-induced internalization and mitogen-activated protein kinase activation of the human prostaglandin EP4 receptor.

We examined the pathway of prostaglandin E(2) (PGE(2))-induced internalization of the prostaglandin EP4 receptor in HEK 293 cells. Co-expression of dominant negative beta-arrestin (319-418) or dynamin I (K44A) with the EP4 receptor reduced internalization. The activated receptor co-localized with GFP-arrestin 2 and GFP-arrestin 3, confirming the requirement for beta-arrestins in internalization. Inhibition of clathrin-coated vesicle-mediated internalization resulted in inhibition of sequestration, whereas inhibition of caveola-mediated internalization had no effect. PGE(2) stimulation of the EP4 receptor resulted in rapid mitogen-activated protein (MAP) kinase activation. Examination of an internalization-resistant mutant and co-expression of mutant accessory proteins with EP4 revealed that MAP kinase activation proceeds independently of internalization.

Acetic Acid↗

PubMed2001

Solar 8B and hep neutrino measurements from 1258 days of Super-Kamiokande data.

Solar neutrino measurements from 1258 days of data from the Super-Kamiokande detector are presented. The measurements are based on recoil electrons in the energy range 5.0-20.0 MeV. The measured solar neutrino flux is 2.32+/-0.03(stat)+0.08-0.07(syst)x10(6) cm(-2) x s(-1), which is 45.1+/-0.5(stat)+1.6-1.4(syst)% of that predicted by the BP2000 SSM. The day vs night flux asymmetry (Phi(n)-Phi(d))/Phi(average) is 0.033+/-0.022(stat)+0.013-0.012(syst). The recoil electron energy spectrum is consistent with no spectral distortion. For the hep neutrino flux, we set a 90% C.L. upper limit of 40x10(3) cm(-2) x s(-1), which is 4.3 times the BP2000 SSM prediction.

Journal Article↗

PubMed2001

Constraints on neutrino oscillations using 1258 days of Super-Kamiokande solar neutrino data.

We report the result of a search for neutrino oscillations using precise measurements of the recoil electron energy spectrum and zenith angle variations of the solar neutrino flux from 1258 days of neutrino-electron scattering data in Super-Kamiokande. The absence of significant zenith angle variation and spectrum distortion places strong constraints on neutrino mixing and mass difference in a flux-independent way. Using the Super-Kamiokande flux measurement in addition, two allowed regions at large mixing are found.

Journal Article↗

PubMed2001

Pilot study comparing the accuracy of lymphoscintigraphy sentinel lymph node localisation with axillary node dissection in women with operable breast cancer.

AIM: To evaluate the use of lymphoscintigraphy sentinel lymph node mapping with scintillation gamma probe detection and blue dye assisted sentinel lymph node biopsy in patients with invasive breast cancer. To compare the lymph nodes detected lymphosintigraphically and at surgery for invasive breast cancer and the accuracy of sentinel node prediction of axillary status. METHODS: A prospective pilot study was performed on 36 women diagnosed with invasive breast cancer requiring axillary node dissection. Lymphoscintigraphy involving peritumoral injection of 99mTechnetium antimony sulphide or rhenium sulphur colloid was performed prior to surgery. Sentinel lymph node biopsy was then performed using gamma probe and blue dye localisation. RESULTS: Sentinel lymph nodes were identified on lymphoscintigrams in 100% of cases, and sentinel nodes located surgically in 34/36 (94.4%) of patients. All women with positive axillary lymph nodes on axillary dissection were correctly identified on sentinel node biopsy. Eight patients demonstrated internal mammary (IM) node radiocolloid uptake, one returning positive IM histology in the presence of positive axillary sentinel node metastasis. CONCLUSION: A high proportion of sentinel nodes were demonstrated by lymphoscintigraphy and were subsequently removed surgically. When internal mammary nodes are identified surgical removal should be considered. In this small series sentinel lymph node status correctly predicted axillary node status in 100% of patients for whom sentinel nodes were retrieved supporting the concept of sentinel node biopsy only for women with normal sentinel lymph nodes. Evidence from randomised trials that sentinel node based management does not compromise regional control of breast cancer or survival, is awaited.

Adult↗

PubMed2001

Quasi-model-independent search for new high p(T) physics at D0.

We apply a quasi-model-independent strategy ("Sleuth") to search for new high p(T) physics in approximately 100 pb(-1) of pp collisions at square root of (s) = 1.8 TeV collected by the D0 experiment during 1992-1996 at the Fermilab Tevatron. We systematically analyze many exclusive final states and demonstrate sensitivity to a variety of models predicting new phenomena at the electroweak scale. No evidence of new high p(T) physics is observed.

Journal Article↗

PubMed2001

An auroral flare at Jupiter.

Jupiter's aurora is the most powerful in the Solar System. It is powered largely by energy extracted from planetary rotation, although there seems also to be a contribution from the solar wind. This contrasts with Earth's aurora, which is generated through the interaction of the solar wind with the magnetosphere. The major features of Jupiter's aurora (based on far-ultraviolet, near-infrared and visible-wavelength observations) include a main oval that generally corotates with the planet and a region of patchy, diffuse emission inside the oval on Jupiter's dusk side. Here we report the discovery of a rapidly evolving, very bright and localized emission poleward of the northern main oval, in a region connected magnetically to Jupiter's outer magnetosphere. The intensity of the emission increased by a factor of 30 within 70 s, and then decreased on a similar timescale, all captured during a single four-minute exposure. This type of flaring emission has not previously been reported for Jupiter (similar, but smaller, transient events have been observed at Earth), and it may be related directly to changes in the solar wind.

Journal Article↗

PubMed2001

Ratio of jet cross sections at square root of s = 630 GeV and 1800 GeV.

The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.

Journal Article↗

PubMed2001

Adenovirus-mediated transfer of inducible caspases: a novel "death switch" gene therapeutic approach to prostate cancer.

In patients with localized prostate cancer, radical prostatectomy and radiation therapy, although effective in controlling localized disease, are often associated with significant side effects attributable to injury of adjacent tissues. Moreover, patients with metastatic disease eventually fail systemic hormonal or chemotherapy because of the development of progressive, refractory disease. In this study, we evaluated the safety and efficacy of a novel suicide gene therapy that could potentially spare normal tissue while bypassing molecular mechanisms of apoptosis resistance by using chemically inducible effector caspases to trigger apoptosis in prostate cancer cells. Initially, we compared the ability of a panel of inducible Fas signaling intermediates to kill human and murine prostate cancer cell lines. On the basis of the superior killing by downstream caspase-1 and caspase-3, replication-deficient adenoviral vectors expressing conditional caspase-1 (Ad-G/iCasp1) or caspase-3 (Ad-G/iCasp3), regulated by nontoxic, lipid-permeable, chemical inducers of dimerization (CID), were constructed. Upon vector transduction followed by CID administration, aggregation and activation of these recombinant caspases occur, leading to rapid apoptosis. In vitro, both human (LNCaP and PC-3) and murine (TRAMP-C2 and TRAMP-C2G) prostate cancer cell lines were efficiently transduced and killed in a CID-dependent fashion. In vivo, direct injection of Ad-G/iCasp1 into s.c. TRAMP-C2 tumors caused focal but extensive apoptosis without evidence for a bystander effect at the maximal viral dose (i.e., 2.5 x 10(10) viral particles/25 microl) in host animals that also received CID compared with control animals. Treatment with Ad-G/iCasp1 plus CID resulted in a transient, yet significant, reduction both in tumor growth and volume compared with tumors treated with vector but not CID (P < 0.035) or vector-diluent plus CID (P < 0.022), both of which grew more rapidly. These results demonstrate that CID-regulated, caspase-based suicide gene therapy is safe and can inhibit the growth of experimental prostate cancer in vitro and in vivo through potent induction of apoptosis, providing a rationale for further development.

Adenocarcinoma↗