Search for narrow tt resonances in pp collisions at square root of (s)=1.8 TeV

A search for narrow resonances that decay into tt pairs has been performed using 130 pb(-1) of data in the lepton + jets channel collected by the Dphi detector in pp collisions at square root of (s)=1.8 TeV. There is no significant deviation observed from the standard-model predictions at a top-quark mass of 175 GeV/c2. We therefore present upper limits at the 95% confidence level on the product of the production cross section and branching fraction to tt for narrow resonances as a function of the resonance mass MX. These limits are used to exclude the existence of a leptophobic top-color particle with mass MX<560 GeV/c2, using a theoretical cross section for a width GammaX=0.012MX.

Treponema denticola immunoinhibitory protein induces irreversible G1 arrest in activated human lymphocytes

Oral spirochetes may contribute to the pathogenesis of a number of disorders including periodontal and periradicular diseases; however, the mechanism (s) by which these organisms act to cause disease is unknown. We have previously shown that extracts of the oral spirochete, Treponema denticola, contain an immunosuppressive protein (Sip) which impairs human lymphocyte proliferation. The objective of this study was to determine the mechanism by which Sip alters the proliferative response of lymphocytes. Human T-cells were activated by PHA in the presence or absence of Sip and cell cycle progression was assessed by flow cytometry. Cell cycle distribution was based upon DNA, RNA and protein content as well as expression of the activation markers; CD69 and IL-2R. Seventy-two hours following activation with PHA, cells were found in the G0, G1, S and G2/M phases of the cell cycle. In contrast, pretreatment with Sip resulted in a significant reduction of cells in the S and G2/M phases and a concomitant increase in the G1 phase. Sip did not alter the expression of the early activation markers CD69 and CD25R. To determine if G1 arrest resulted in activation of the checkpoint and cell death, we also monitored Sip-treated cells for apoptosis. Indeed, treatment with Sip resulted in both DNA fragmentation and caspase activation after 96 h. Our results indicate that Sip induces G1 arrest in human T-cells and, furthermore, that the arrest is irreversible, culminating in activation of the apoptotic cascade. We propose that if cell cycle arrest occurs in vivo, it may result in local and/or systemic immunosuppression and thereby enhance the pathogenicity of spirochetes and/or that of other opportunistic organisms.

Systemic-to-pulmonary venous shunt in superior vena cava obstruction: depiction on computed tomography venography

PURPOSE

To describe computed tomography (CT) venographic appearances of systemic-to-pulmonary venous shunts with CT venography and three-dimensional reconstruction images from patients with superior vena cava obstruction.

MATERIAL AND METHODS

From January 1994 to April 2002, CT venography was performed in 45 patients with superior vena cava obstruction using a single-detector helical CT scanner (n=38) and four-detector row CT scanner (n=7). Analysis of CT scan data included the cause and degree of venous obstruction, the presence of pleural thickening and enhancement, and the attenuation of pulmonary veins. The causative factor for systemic-to-pulmonary venous shunt was evaluated using the Fisher exact test.

RESULTS

Systemic-to-pulmonary venous shunts were observed in four patients (9%) who had high-attenuated pulmonary veins and pleural enhancement on CT venography. Pleural thickening (P=0.01) and a history of pulmonary tuberculosis (P=0.034) are statistically significant risk factors.

CONCLUSION

CT venography showed strong pleural enhancement and high-attenuated pulmonary veins indicating systemic-to-pulmonary venous shunts. Radiologists should study the earlier enhancement of pulmonary veins in patients with superior vena cava obstruction.

[Immunodiagnosis of endemic mycoses and bronchopulmonary aspergillosis: a multicenter study in Argentina]

In order to contribute to the knowledge of the relative frequency of chronic fungal diseases and assess the performance of diagnostic laboratories in Argentina, a multicenter study was performed with the participation of 25 medical centers located in 12 different provinces and Buenos Aires City. Between 04-01-2000 and 03-30-2001, 965 serum specimens from patients clinically suspected of having histoplasmosis (HP), paracoccidioidomycosis (PCM), coccidioidomycosis (CM) or aspergilosis were analyzed. Agar immunodiffusion tests (IDD) were done locally. All positive and 35% of negative sera were retested in the reference center. Results of laboratories of origin showed 98.8% concordance with those of reference center. Antibodies against any of the etiological agents were detected in 120 specimens from 98 patients. Endemic mycoses (HP, PCM and CM) were diagnosed in 70 patients (71.4%) and aspergilosis in 28 (28.6%). The frequencies of the different mycoses in decreasing order were PCM 47 patients (47.9%), aspergilosis 28 patients (28.6%), HP 13 patients (13.3%) and CM 10 patients (10.2%). The study was carried out on a voluntary basis and some areas of the country were not represented. However, the frequencies were in range with the expected rates in the population under study.

Therapeutic vaccine generated by electrofusion of dendritic cells and tumour cells

Immunotherapy with fusion of dendritic cells (DCs) and tumour cells potentially confers the advantages of DC antigen-presenting functionality and a continuous source of unaltered tumour antigens. However, fusion using chemical or viral fusogens has been inefficient. We have recently developed a high throughput electrofusion technique with which very efficient fusion rates (15-54%) were observed in over 300 experiments, using a variety of murine and human tumour cell lines. The fused cells display a mature DC phenotype and express tumour-associated antigens. In two pre-clinical animal models (B16 melanoma transduced with the LacZ gene and the MCA 205 fibrosarcoma), a single vaccination of mice bearing tumours established in the lung, brain and skin resulted in tumour regression and prolongation of life. However, therapeutic efficacy required the administration of adjuvants such as IL-12 and OX-40R mAbs. Effective immunotherapy also required the delivery of fusion cells directly into lymphoid organs (spleen or lymph nodes). Using five defined human T cell lines derived from melanoma patients, allogeneic DCs of HLA-A2, HLA-DR4 and HLA-DR7 haplotypes fused with MART-1, gp100, tyrosinase and TRP-2 expressing 888 mel melanoma cells were analysed for their ability to stimulate specific cytokine (IFN-gamma and GM-CSF) secretion. DC-888 mel hybrids presented all tumour-associated epitopes to both CD4 and CD8 T cell lines in the context of MHC class II and I molecules, respectively. The therapeutic efficacy of a DC-tumour fusion vaccine is now being evaluated for the treatment of metastatic melanoma.

Unique structural features of a BCL-2 family protein CED-9 and biophysical characterization of CED-9/EGL-1 interactions

The interactions between B-cell lymphoma 2 (BCL-2) family members are known to be mediated through the binding of the BH3 domain of a proapoptotic member to the BH3-binding groove of an antiapoptotic member. We determined the crystal structure of antiapoptotic CED-9, which reveals a unique C-terminal helix altering the common BH3-binding region. A coexpression system to produce CED-9 in complex with proapoptotic EGL-1 enabled us to show that the binding of EGL-1 to CED-9 is extremely stable, raising the melting temperature (T(M)) of CED-9 by 25 degrees C, and that the binding surface of CED-9 extends beyond the BH3-binding region and reaches the BH4 domain. Consistently, the T(M) and a 1H-15N correlation NMR spectrum of CED-9 in complex with EGL-1 are drastically different from those of CED-9 in complex with the EGL-1 BH3 peptide. The data suggest that the recognition between other BCL-2 family members may also involve much wider protein surfaces than is previously thought.

J/psi polarization in 800-GeV p-Cu interactions

We present measurements of the polarization of the J/psi produced in 800-GeV proton interactions with a copper target. Polarization of the J/psi is sensitive to the ccmacr; production and hadronization processes. A longitudinal polarization is observed at large x(F), while at small x(F) the state is produced essentially unpolarized or slightly transversely polarized. No significant variation of the polarization is observed versus p(T).

Dynamic optical manipulation with a higher-order fractional bessel beam generated from a spatial light modulator

Higher-order Bessel beams have been demonstrated to have the ability to trap and rotate low- and high-index particles simultaneously [Phys. Rev. A 66, 063402 (2002)]. The rotation and trapping is caused by the presence of orbital angular momentum arising from its azimuthal phase variation (that changes at integer multiples of 2pi) and the concentric rings of the Bessel mode. We demonstrate for the first time to our knowledge a branch from the family of higher-order Bessel beams that has fractional azimuthal variation at its beam axis. This new family of laser beams has the ability to perform dynamic optical manipulation with dynamic control of a spatial light modulator. Furthermore, we take the opportunity to explore the propagation characteristics of higher-order Bessel beams for which the azimuthal phase changes at noninteger multiples of 2pi.

Adoptive cellular immunotherapy for non-small cell lung cancer: a pilot study

BACKGROUND

Priming with autologous tumor vaccine followed by ex vivo expansion of activated T cells is a feasible experimental strategy. This paper describes the application of this cellular therapy to treat patients with late-stage non-small-cell lung cancer (NSCLC).

METHODS

Twenty-one patients with Stages III and IV NSCLC were treated. Tumor samples were obtained surgically (five patients) or by using aco-axial biopsy needle (16 patients). Each course of vaccination consisted of irradiated tumor cells, mixed with GM-CSF and injected intradermally on Day 1, followed by GM-CSF only on Days 2- 5. The course was repeated 10-14 days later. Lymphocytes were collected 10-14 day after the second course and ex vivo expanded using IL-2 and anti-CD3 Ab. The expansion products were then re-infused into the patients.

RESULTS

Twelve out of 16 biopsies resulted in optimal cell numbers for vaccine preparation. Nineteen out of 21 patients achieved a delayed type hypersensitivity (DTH response after two courses of vaccination. In 18/21 patients, the ex vivo expansion products contained > 1.6 x 10(10) cells. Subset analysis showed 77.0-97.2% T cells with a CD4:CD8 ratio of 0.65-4.0; natural killer cells were 2.0-18.6%. There were no significant toxicities. The median survival of all 21 patients was 18.6 months, with a 1-year survival of 51.6%.

CONCLUSION

Autologous tumor cell-vaccination may be combined with ex vivo expansion of lymphocytes as adoptive cellular immunotherapy for advanced NSCLC. Overall survival in this cohort of poor prognosis patients compared favorably with results reported in the literature.

Transanal endoscopic microsurgery and radical surgery for T1 and T2 rectal cancer

BACKGROUND

Transanal endoscopic microsurgery (TEM) has gained increasing acceptance as a local treatment of early rectal cancer. The purpose of this study was to compare the results of TEM and radical surgery in patients with T1 and T2 rectal cancer.

METHODS

From October 1994 to December 2000, 74 patients with T1 and T2 rectal adenocarcinoma treated with TEM were compared with 100 patients with T1N0M0 and T2N0M0 rectal adenocarcinoma treated with radical surgery. Retrospective analysis was performed regarding to recurrence and survival rate. Neither group received adjuvant chemoradiation. There was no significant difference in age, gender, tumor location, or follow-up period between the two groups. The only difference was in tumor size.

RESULTS

Of the 74 patients in TEM group, 52 were T1 (70.3%) and 22 were T2 (29.7%). Of the 100 patients in radical surgery group, 17 were T1 (17%) and 83 patients were T2 (83%). The 5-year local recurrence rates were 4.1% for T1, 19.5% for T2 after TEM, 0% for T1, and 9.4% for T2 after radical surgery. There was no statistical difference between the TEM and radical surgery groups for T1 rectal cancer ( p = 0.95), but for T2 rectal cancer, the 5-year local recurrence rate was higher after TEM than after radical surgery ( p = 0.04). There were no significant statistical difference between the two groups in terms of the 5-year disease-free survival rate and the survival rate.

CONCLUSIONS

For T1 rectal cancer, there was no difference in recurrence or 5-year survival rate between the TEM and the radical surgery groups. For T2 rectal cancer, there was no statistical difference in the 5-year survival rate between the two groups, but TEM carried higher risk of local recurrence. Therefore, careful selection of the patients is required for TEM, and when proper muscle invasion is proven, the TEM procedure should be supplemented by further treatment, or radical surgery should be performed.

[Malassezia species isolated from skin diseases in a care center in the city of Buenos Aires, Argentina]

The epidemiology of Malassezia genus is poorly understood; geographical and population factors might have influence on the species distribution. The aim of this work was to determine the frequency of Malassezia species involved in skin diseases in a diagnostic center at Buenos Aires City. From 02/01/1999 to 10/31/2001, 456 skin specimens from 447 patients diagnosed as pityriasis versicolor, seborrheic dermatitis, foliculitis and atopic dermatitis, were analyzed by microscopic examination and culture. Malassezia spp was evidenced in 255 skin samples (55.9%) by microscopic analysis but it could be recovered from only 99 (38.8%) specimens. Malassezia species were isolated from 10 (3.9%) scarring lesions that were negative by microscopy. Among 109 isolates, M. sympodialis (58.7%) was the most frequent, followed by M. globosa and M. furfur (18.3% and 9.2%). Unique isolates (0.9%) of M. obtusa, M. slooffiae and M. restricta were recovered. Eleven isolates (10.1%) could not be identified because they had lost viability in the culture. This is the first study on Malassezia species associated to skin diseases in Argentina; further screening including other geographic regions of the country is necessary in order to confirm these results.

Diffusion-weighted MR imaging in intracranial infections

INTRODUCTION

Diffusion-weighted magnetic resonance (MR) imaging (DWMRI) is valuable in the assessment of acute cerebral infarction and may be useful for other diseases of the central nervous system (CNS). In this study, we present the DWMRI appearance of intracranial infection.

MATERIALS AND METHODS

Thirty patients with clinical diagnosis of CNS infection were reviewed. All patients underwent conventional contrast-enhanced MR examination and DWMRI using single-shot echo-planar imaging at b = 1000 s/mm2.

RESULTS

Cerebral abscess, tuberculoma, subdural empyema and epidural abscess were hyperintense on DWMRI. Neurocysticercosis showed hypointense lesions on DWMRI. Four of 5 patients with encephalitis showed DWMRI hyperintensity; the appearance of toxoplasmosis lesions was variable. Patients suffering from meningitis without parenchymal involvement did not exhibit any abnormality of diffusion. One patient with tuberculous meningitis developed abnormality on DWMRI from acute cerebral infarction.

CONCLUSION

DWMRI increased lesion conspicuity and may be useful in assessment of cerebral infection. There were striking differences in the DWMRI appearances caused by different organisms and diseases.

Search for large extra dimensions in the monojet+E(T) channel with the DØ detector

We present a search for large extra dimensions (ED) in pp collisions at a center-of-mass energy of 1.8 TeV using data collected by the DØ detector at the Fermilab Tevatron in 1994-1996. Data corresponding to 78.8+/-3.9 pb(-1) are examined for events with large missing transverse energy, one high-p(T) jet, and no isolated muons. There is no excess observed beyond expectation from the standard model, and we place lower limits on the fundamental Planck scale of 1.0 and 0.6 TeV for 2 and 7 ED, respectively.

Severe gingival hyperplasia in a child with I-cell disease

I-cell disease (mucolipidosis II) is a rare metabolic disorder resulting from the deficiency of a specific lysosomal enzyme, N-acetylglucosamine-1-phosphotransferease. The disease presents as a mental and motor developmental delay with oral manifestations that include severe gingival hyperplasia usually seen before one year of age. The life expectancy of children with this condition is poor, with death usually occurring around the fifth year. A case report of a 3-year-old Pakistani male, with I-cell disease, is presented. The chief dental concerns of the parents were his swollen gums and delayed tooth eruption. Supportive treatment only was initiated. Differential diagnosis for severe gingival overgrowth in young patients should take account of this rare metabolic disorder in addition to hereditary and idiopathic fibromatosis and drug associated gingival overgrowth.

Accuracy of electrical field measurement using the flexible Schottky diode sheet at 433 MHz

In this study, the accuracy of Schottky diode sensors mounted as a two-dimensional array on a flexible 125 micro m thick polyester foil has been studied. The diodes are placed at a distance of 2.5 x 2.5 cm, resulting in a measuring area of 20 x 20 cm. The diodes are placed across the gap between both arms (3 x 5 mm) of a dipole, total length 12 mm. High resistance (1 M Omega/m) carbon transmission lines printed on the sheet are used to connect each electrical (E) field sensor to the read-out electronics and a data-acquisition system. It is demonstrated that the flexible Schottky diode sheet can quantitatively measure E-field distributions at 433 MHz with an overall accuracy of approximately 6% (1 SD). The largest contribution to the inaccuracy is related to the phantom heterogeneity. The absolute sensitivity of this electrical field sensor is 0.71 V/m per V/m of the applied external electromagnetic field. The DC-voltage signal of the diodes shows a more or less square root relation to the RF-power applied to the applicator over a 15-fold range. An important feature of the system is that it provides the ability to perform on-line monitoring of the E-field, i.e. the SAR distribution of 433 MHz applicators. Further, it enables the introduction of fast and easy quality control protocols for superficial hyperthermia applicators.