Z Boson Decay into Light and Darkness

We study the Z→γγ[over ¯] process in which the Z boson decays into a photon γ and a massless dark photon γ[over ¯], when the latter couples to standard-model fermions via dipole moments. This is a simple yet nontrivial example of how the Landau-Yang theorem-ruling out the decay of a massive spin-1 particle into two photons-is evaded if the final particles can be distinguished. The striking signature of this process is a resonant monochromatic single photon in the Z-boson center of mass together with missing momentum. LEP experimental bounds allow a branching ratio up to about 10^{-6} for such a decay. In a simplified model of the dark sector, the dark-photon dipole moments arise from one-loop exchange of heavy dark fermions and scalar messengers. The corresponding prediction for the rare Z→γγ[over ¯] decay width can be explored with the large samples of Z bosons foreseen at future colliders.

Saccharomyces cerevisiae-based probiotic as novel anti-fungal and anti-inflammatory agent for therapy of vaginal candidiasis

Previously we demonstrated that the treatment with live Saccharomyces cerevisiae exerts beneficial therapeutic effects against vaginal candidiasis. Here, we address potential mechanisms particularly examining the probiotic capacity to modulate both fungus and host-related factors. We show that the S. cerevisiae-based probiotic markedly affects the expression of virulence traits of Candida albicans such as aspartyl proteinases (SAPs) as well as hyphae-associated proteins Hwp1 and Ece1 in the vaginal cavity. On the host side, the probiotic suppression of the influx of neutrophils caused by the fungus into the vaginas of the mice is likely related to: (1) lower production of interleukin-8; and (2) inhibition of SAPs expression. However, these neutrophils displayed reactive oxygen species hyperproduction and increased killing activity as compared to the neutrophils of placebo-treated mice. There was no evidence of any cytotoxic effect by the probiotic, either when used in vivo on vaginal epithelial cell and organ architecture, or in in vitro in human vaginal epithelium. Inactivated yeast cells did not affect any of the factors above. In summary, the data suggest that the beneficial effect exerted by this S. cerevisiae-based probiotic is the result of its interference with the expression of fungus virulence factors coupled with the modulation of the inflammatory response of the host.

Long-term outcomes of central neck dissection for cN0 papillary thyroid carcinoma

OBJECTIVE

The risk-benefit ratio of central neck dissection (CND) in patients affected by papillary thyroid carcinoma (PTC) without clinical or ultrasonographic (US) evidence of neck lymph node metastasis (cN0) is currently debated. The aim of this study was to evaluate long-term outcome of CND on locoregional recurrence, distant metastasis, survival, and postoperative complications in a large series of patients with cN0-PTC.

STUDY DESIGN

Observational retrospective controlled study.

METHODS

Clinical records of patients (n=610) surgically treated for cN0-PTC at the Otolaryngology Unit of the Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy, from January 1984 to December 2008, were retrospectively reviewed. Study population was divided into three groups according to surgical treatment: Group A, total thyroidectomy (n=205); Group B, total thyroidectomy and elective ipsilateral CND (n=281); Group C, total thyroidectomy and bilateral CND (n=124).

RESULTS

Of a total of 610 patients, 305 (50%) were classified as low-risk, 278 (45.57%) as intermediate-risk, and 27 (4.43%) as high-risk. Response to initial therapy was excellent in 567 patients (92.95%), acceptable in 21 (3.44%), and incomplete in 22 (3.61%), with no significant differences among groups. Locoregional recurrence was detected in 32 (5.2%) out of 610 patients. Distant metastasis was found in 15 patients (2.5%). Statistical analysis showed no significant differences in the rates of locoregional recurrence (p=0.890) or distant metastasis (p=0.538) among groups. Disease-specific mortality and overall survival did not significantly differ among groups (p=0.248 and 0.223, respectively). Rate of permanent hypoparathyroidism was significantly higher in Group C patients compared to those in Groups A and B.

CONCLUSION

CND does not confer any clear advantage in the treatment of low-risk patients, regardless of surgical procedure. Instead, bilateral CND may be effective in limiting disease relapse and/or progression in patients at higher prognostic risk. Our data indicate that elective CND does not confer any clear advantage in terms of locoregional recurrence and long-term survival, as demonstrated by outcomes of the study Groups, regardless of their different prognostic risk. Elective CND allows a more accurate pathologic staging of central neck lymph nodes, despite its increasing the risk of permanent hypoparathyroidism. Intraoperative pathologic staging is a valuable tool to assess the risk of controlateral lymph node metastasis in the central neck compartment and to limit more aggressive surgery only to cases, otherwise understaged, with lymph node metastasis.

Hunting Down Massless Dark Photons in Kaon Physics

If dark photons are massless, they couple to standard-model particles only via higher dimensional operators, while direct (renormalizable) interactions induced by kinetic mixing, which motivates most of the current experimental searches, are absent. We consider the effect of possible flavor-changing magnetic-dipole couplings of massless dark photons in kaon physics. In particular, we study the branching ratio for the process K^{+}→π^{+}π^{0}γ[over ¯] with a simplified-model approach, assuming the chiral quark model to evaluate the hadronic matrix element. Possible effects in the K^{0}-K[over ¯]^{0} mixing are taken into account. We find that branching ratios up to O(10^{-7}) are allowed-depending on the dark-sector masses and couplings. Such large branching ratios for K^{+}→π^{+}π^{0}γ[over ¯] could be of interest for experiments dedicated to rare K^{+} decays like NA62 at CERN, where γ[over ¯] can be detected as a massless invisible system.

Lateral neck recurrence from papillary thyroid carcinoma: Predictive factors and prognostic significance

OBJECTIVES/HYPOTHESIS

The aim of this study was to identify any possible predictive factors of lateral neck recurrence in patients with papillary thyroid carcinoma with no ultrasonographic and/or cytological evidence of lymph node metastasis at time of diagnosis. The influence of lateral neck recurrence on survival was also investigated.

STUDY DESIGN

Observational retrospective study.

METHODS

Retrospective review of clinical records of 610 patients surgically treated for papillary thyroid carcinoma with clinically negative lymph nodes at the Otolaryngology Unit of the Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy, from January 1984 to December 2008.

RESULTS

Lateral neck recurrences were ipsilateral to the primary tumor in all cases and were associated with the occurrence of more aggressive histological variants and central neck metastasis. Lateral neck recurrences were more frequently observed in patients with distant metastases and were associated with a reduced disease-specific survival.

CONCLUSION

Lateral neck compartment ipsilateral to the tumor was the most common site of recurrence, with about half of cases appearing in the first 28 months of follow-up. In patients with papillary thyroid carcinoma, detection of lateral neck metastases prior to first surgery is crucial to surgical planning. Aggressive histological variants and postsurgical evidence of lymph node metastasis from papillary thyroid carcinoma in central neck compartment are associated with a higher risk of lateral neck recurrence. In these patients, a closer postsurgical ultrasound surveillance of the lateral neck compartments seems worthwhile.

LEVEL OF EVIDENCE

4.

Osteomyelitis caused by Aspergillus species: a review of 310 reported cases

Aspergillus osteomyelitis is a rare infection. We reviewed 310 individual cases reported in the literature from 1936 to 2013. The median age of patients was 43 years (range, 0-86 years), and 59% were males. Comorbidities associated with this infection included chronic granulomatous disease (19%), haematological malignancies (11%), transplantation (11%), diabetes (6%), pulmonary disease (4%), steroid therapy (4%), and human immunodeficiency virus infection (4%). Sites of infection included the spine (49%), base of the skull, paranasal sinuses and jaw (18%), ribs (9%), long bones (9%), sternum (5%), and chest wall (4%). The most common infecting species were Aspergillus fumigatus (55%), Aspergillus flavus (12%), and Aspergillus nidulans (7%). Sixty-two per cent of the individual cases were treated with a combination of an antifungal regimen and surgery. Amphotericin B was the antifungal drug most commonly used, followed by itraconazole and voriconazole. Several combination or sequential therapies were also used experimentally. The overall crude mortality rate was 25%.

Daptomycin and rifampin alone and in combination prevent vascular graft biofilm formation and emergence of antibiotic resistance in a subcutaneous rat pouch model of staphylococcal infection

OBJECTIVE

To investigate the efficacy of daptomycin and rifampin either alone or in combination in preventing prosthesis biofilm in a rat model of staphylococcal vascular graft infection.

DESIGN

Prospective, randomised, controlled animal study.

MATERIALS

Graft infections were established in the back subcutaneous tissue of adult male Wistar rats by implantation of Dacron prostheses followed by topical inoculation with 2×10(7) colony forming units of Staphylococcus aureus, strain Smith diffuse.

METHODS

The study included a control group, a contaminated group that did not receive any antibiotic prophylaxis and three contaminated groups that received intra-peritoneal daptomycin, rifampin-soaked graft and daptomycin plus rifampin-soaked graft, respectively. Each group included 15 animals. The infection burden was evaluated by using sonication and quantitative agar culture. Moreover, an in vitro antibiotic susceptibility assay for S. aureus biofilms was performed to elucidate the same activity.

RESULTS

When tested alone, daptomycin and rifampin showed good efficacies. Their combination showed efficacies significantly higher than that of each single compound. The in vitro studies showed that minimum inhibitory concentration and minimum bactericidal concentration values for daptomycin were lower in presence of rifampin. Daptomycin prevented the emergence of rifampin resistance.

CONCLUSION

Daptomycin is an important candidate for prevention of staphylococcal biofilm-related infection and rifampin could serve as an interesting anti-staphylococcal antibiotic enhancer.

In vitro activity of the lipopeptide PAL-Lys-Lys-NH2, alone and in combination with antifungal agents, against clinical isolates of Candida spp

Candida albicans is known to be the organism most often associated with serious fungal infection, but other Candida spp. are emerging as clinical pathogens associated with opportunistic infections. Among antimycotic treatments, increasing attention is currently given to anti-infective drugs based upon naturally occurring peptides, such as the short lipopeptide palmitoyl PAL-Lys-Lys-NH2 (PAL). The aim of this study is to evaluate the activity of this peptide compared to the traditional antifungal agents Fluconazole (FLU), amphotericin B (AMB) and caspofungin (CAS) on Candida spp. 24 clinical isolates of Candida spp. were tested against PAL, FLU, AMB and CAS using in vitro susceptibility tests, time killing and checkerboard assay. All of the drugs studied showed good activity against clinical isolates of candida; in particular CAS and AMB which have MICs value lower than PAL and FLU. Moreover we observed synergistic interactions for PAL/FLU (81.25%), PAL/AMB (75%) and particularly for PAL/CAS (87.5). We think that our results are interesting since synergy between PAL and CAS might be useful in clinic trails to treat invasive fungal infections.

In vitro activity of Tachyplesin III alone and in combination with terbinafine against clinical isolates of dermatophytes

Aim of our study was to investigate the in vitro effects of Tachyplesin III (TP), a potent disulfide-linked peptide, in dermatophytes infections, with respect to or in combination with terbinafine (TERB), against 20 clinical isolates of dermatophytes belonging to four species. A broth microdilution method following the CLSI recommendations (M38-A) was used for testing drugs alone and in combination. TERB MICs were significantly lower than those observed for TP (p<0.001). Testing for antifungal agents in combination was performed for TERB with TP for all the 20 isolates. TERB activity in combination with TP showed indifferent activity for 14 of the 20 isolates (70%); synergic activity for 6 of the 20 isolates (30%); no antagonistic activity was observed. Further experiments were conducted with Microsporum canis 133, Trichophyton rubrum 62 and Trichophyton mentagrophytes 91 for fungal biomass. TP and TERB did not show a significant growth reduction compared to the control against T. mentagrophytes and T. rubrum. A significant difference of growth reduction both for TP and TERB compared to controls was observed for M. canis (p<0.01). In conclusion our study demonstrated that Tachyplesin III has potential activity against dermatophytes. In addition, we observed that the in vitro activity of Tachyplesin III can be enhanced upon combination with terbinafine. Synergy could permit lower doses of the individual antifungal agents to be used more effectively and/or safely.