Variable Very-High-Energy Gamma-Ray Emission from the Microquasar LS I +61 303

Microquasars are binary star systems with relativistic radio-emitting jets. They are potential sources of cosmic rays and can be used to elucidate the physics of relativistic jets. We report the detection of variable gamma-ray emission above 100 gigaelectron volts from the microquasar LS I 61 + 303. Six orbital cycles were recorded. Several detections occur at a similar orbital phase, which suggests that the emission is periodic. The strongest gamma-ray emission is not observed when the two stars are closest to one another, implying a strong orbital modulation of the emission or absorption processes.

Chemical composition and physical features of summer aerosol at Terra Nova Bay and Dome C, Antarctica

During the 2002-2003 austral summer field season, aerosol samples were collected at a coastal (Terra Nova Bay--Northern Victoria Land) and an inland site (Dome C--East Antarctic Plateau). The sampling was carried out by stacked filter units made up of two filters at different porosity (5.0 and 0.4 microm at Terra Nova Bay and 3.0 and 0.4 microm at Dome C), able to roughly separate a coarse from a fine fraction. At Dome C, a further investigation on aerosol size distribution was performed by an inertial impactor able to collect aerosol particles on 8 size classes (from 10 to 0.4 microm). Atomic Force Microscopy was applied to the filter collecting the finer fraction in both sites in order to assess the real cut-off value of the filter sandwich apparatus and to reconstruct the volume size distribution. At the employed flow conditions, the real cut-off value was revealed to be about one third with respect to the filter nominal porosity in both stations. The size distribution plots showed a bimodal distribution with a mode centered around 0.22 microm in both the sites and a second broader mode which is centered between 0.3 microm and 1.2 microm diameter at Terra Nova Bay and shifted toward higher values (centred around 1.0 microm diameter) at Dome C. Each filter was analysed for the main and trace ionic components allowing evaluation of the contributions of primary and secondary aerosol sources at the two sites as a function of the particle size class. The coastal site is mainly affected by primary and secondary marine inputs: the sea spray contribution (Na+, Mg2+, Cl- and ssSO4(2-)) is dominant (77% w/w) in the coarse fraction whereas the biogenic source (methanesulfonate and nssSO4(2-)) prevails (67.5% w/w) in the fine fraction. In this fraction a significant contribution (15.5% w/w) is provided by ammonium likely to be related to surrounding penguin colonies. Dome C atmosphere is characterised by fine particles arising from secondary sources and long-range transport processes. The main component in the fine and coarse fractions at Dome C is sulfate whose nssSO4(2-) represents the 99.5% and the 92.3%(w/w) in fine and coarse fraction, respectively. The observed agreement between nssSO4(2-) and methanesulfonate temporal profiles in the fine fraction demonstrates that biogenic emissions dominate the inland background aerosol. Results from the sampling by the 8-stage impactor at Dome C are presented here: chloride and nitrate are mainly deposited on the 10-2.1 microm stages while the highest sulfate concentration was found in the submicrometric fraction which turned out to be the most acidic. Such a distribution is able to prevent nitrate and chloride re-emission as gaseous HCl and HNO3 in the 10-2.1 microm stages, arising from the exchange reaction between chloride and nitrate salts and sulfuric acid. Moreover, the concentration peak observed for nitrate in coarser fractions is probably related also to the formation of hygroscopic NH4NO3 particles and nitrate adsorption on sea salt particles.

Open-shell localized Hartree–Fock method based on the generalized adiabatic connection Kohn–Sham formalism for a self-consistent treatment of excited states

An effective exact-exchange Kohn-Sham approach for the treatment of excited electronic states, the generalized adiabatic connection open-shell localized Hartree-Fock (GAC-OSLHF) method is presented. The GAC-OSLHF method is based on the generalized adiabatic connection Kohn-Sham formalism and therefore capable of treating excited electronic states, which are not the energetically lowest of their symmetry. The method is self-interaction free and allows for a fully self-consistent computation of excited valence as well as Rydberg states. Results for atoms and small- and medium-size molecules are presented and compared to restricted open-shell Hartree-Fock (ROHF) and time-dependent density-functional results as well as to experimental data. While GAC-OSLHF and ROHF results are quite close to each other, the GAC-OSLHF method shows a much better convergence behavior. Moreover, the GAC-OSLHF method as a Kohn-Sham method, in contrast to the ROHF approach, represents a framework which allows also for a treatment of correlation besides an exchange by appropriate functionals. In contrast to the common time-dependent density-functional methods, the GAC-OSLHF approach is capable of treating doubly or multiply excited states and can be easily applied to molecules with an open-shell ground state. On the nodal planes of the energetically highest occupied orbital, the local multiplicative GAC-OSLHF exchange potential asymptotically approaches a different, i.e., nonzero, value than in other regions, an asymptotic behavior which is known from exact Kohn-Sham exchange potentials of ground states of molecules.

The effects of oxygenation on the optical properties of dimethyl-dithienothiophenes: Comparison between experiments and first-principles calculations

Modifications of the optical properties of dimethyl-dithienothiophenes due to the oxygen functionalization of the central sulfur atom are investigated. We have measured the absorption, photoluminescence (PL) and PL excitation spectra, the PL quantum efficiencies, and the PL decay times. These experimental results are interpreted and compared with first-principles time-dependent density-functional theory calculations, which predict, for the considered systems, excitation and emission energies with an accuracy of 0.1 eV. It is found that the oxygenation strongly changes optical and photophysical properties. These effects are related to the modifications of the energetically lowest-unoccupied molecular orbital and the energetically second highest occupied one, which change the relative position of the two lowest singlet and triplet excited states.

Bluetongue surveillance in the Campania Region of Italy using a geographic information system to create risk maps

The aim of the project was the implementation of a geographic information system (GIS) to study areas of the Campania Region that are potentially at risk for bluetongue (BT) infection. As a first step, environmental, meteorological and climatic features were surveyed to evaluate areas where Culicoides could be present. A risk map was developed and five zones with different risk levels were defined. Data from Culicoides trapping were surveyed to evaluate the capability of the risk map to predict presence/absence of vectors. Finally, data from 2002 BT surveillance (outbreaks and serologically positive sentinels [SPS]) were compared to the map. Captures of Culicoides, SPS and BT in areas the map indicated as a medium/high risk level, seem to confirm reliability of the produced map. However, very few C. imicola were captured in these medium/high risk areas.

Alternating gemcitabine and cisplatin with gemcitabine and radiation in stage IV squamous cell carcinoma of the head and neck

BACKGROUND

In order to improve our cisplatin-5-fluorouracil (5-FU)-based alternating chemo-radiotherapy regimen, in 1996 we started an investigational program to explore a modified alternating regimen including gemcitabine given both with radiosensitizing and cytotoxic intent.

MATERIALS AND METHODS

Based on our previous feasibility trial, we conducted a second study testing the feasibility and activity of the following schedule: gemcitabine 800 mg/m(2) on day 1 and cisplatin 20 mg/m(2) on days 2-5 (weeks 1, 4, 7 and 10) alternated with three courses of radiotherapy (RT) (weeks 2-3, 5-6 and 8-9) with conventional fractionation up to 60 Gy. Gemcitabine 300 mg/m(2) was also administered on the Monday of each week of RT.

RESULTS

Forty-seven patients with stage IV (41 patients) unresectable squamous cell carcinoma of the head and neck (SCC-HN) or who had relapsed after surgery (6 patients) were enrolled. None had previously received chemotherapy or radiotherapy. Eight patients (18%) did not complete the treatment. Main grade 3-4 toxicities were as follows: neutropenia (44%); neutropenia with fever (12%); thrombocytopenia (37%); anemia (30% grade 3). One patient died in therapy due to sepsis. Most patients needed hospitalization and tube-feeding or parenteral nutrition. However, 44% of patients had a weight loss >10%. Thirty-four patients had a complete response (72%). Three partial responders were rendered disease-free by surgery (final complete response rate, 79%). At a median follow-up of 38 months actuarial 3-year overall survival, progression-free survival and loco-regional control are 43%, 39% and 64%, respectively. Data of locoregional control favorably compare with those from our database of patients treated with alternating cisplatin-fluorouracil and radiation within controlled clinical trials (64% versus 40%).

CONCLUSIONS

The inclusion of gemcitabine into an alternating regimen seems to improve the results achievable with the original alternating program in stage IV patients. However, due to the high acute toxicity correlated, this intensive regimen should be managed by institutions well trained in multidisciplinary treatments.

Impact of the treating institution on the survival of patients with head and neck cancer treated with concomitant alternating chemotherapy and radiation

The aim of this study was to investigate the possible impact of the treating institution on the survival of patients with advanced squamous cell carcinoma of the head and neck treated with radiotherapy alone or concomitant alternating chemotherapy and radiation. The National Institute for Cancer Research of Genoa (IST) was the coordinator of two multicentre randomised trials comparing an alternating chemotherapy and radiation approach to radiotherapy alone with standard fractionation (HN-8 trial: 157 patients) or accelerated fractionation (HN-9 trial: 136 patients) in patients with advanced squamous-cell carcinoma of the head and neck. A single database of the two studies was created and a univariate analysis was performed. The Cox regression model, adjusted for the effect of other prognostic factors, was used to test the impact of the treating institution on survival. Three-year overall survival was 46% for patients treated with chemotherapy and radiation at the coordinating centre and 27% for those treated with the same approach at the affiliated centres (P=0.0001). No difference was detected between patients treated with radiation alone at the coordinating centre or outside (23% versus 21%: P=0.52). The hazard ratio of death for patients treated at the affiliated centres with concomitant alternating chemotherapy and radiation was 2.15 (95% Confidence Interval (C.I.) 1.45-3.18), while it was 1.003 (95% C.I. 0.65-1.55) for those treated with radiation alone. In our experience, the treating institution had a significant impact only on the prognosis of patients treated with the multidisciplinary approach. This finding has implications, both in terms of clinical research and clinical practice.

Low-dose fractionated total body irradiation (TBI) adversely affects prognosis of patients with leukemia receiving an HLA-matched allogeneic bone marrow transplant from an unrelated donor (UD-BMT)

The optimal total body irradiation (TBI) regimen for unrelated donor bone marrow transplant (UD-BMT) is unknown. In the present study we analyze the outcomes of two different TBI regimens used in our center for patients with leukemia undergoing an UD-BMT. Between January 1994 and August 2001, 99 consecutive UD-BMT patients entered this comparative study. The conditioning regimen consisted of cyclophosphamide, 120 mg/kg followed by TBI on days -3, -2 and -1. Forty-six patients received TBI 12 Gy (2 Gy, twice a day) in six fractions (HF-TBI) and 53 patients received TBI 9.90 Gy (3.30 Gy per day) fractionated over 3 days (F-TBI). End-points were transplanted-related mortality (TRM), leukemia relapse rate (LRR) and overall survival (OS). At median follow-up of 22 months (58 months for HF-TBI and 17 for F-TBI, respectively), 60 patients were alive (32 in HF-TBI sub-group and 28 in F-TBI one). The actuarial 5-year TRM was 31% for HF-TBI and 41% for F-TBI (P = 0.1), whereas the 5-year LRR was 13% for HF-TBI and 31% for F-TBI (P = 0.04). The actuarial 5-year OS was 68% for patients treated with HF-TBI and 51% for those treated with F-TBI (P = 0.02). At multivariate analysis F-TBI schedule emerged as an adverse predictor for OS (P = 0.04) and LRR (P = 0.03). These data indicate that a lower total dose of TBI appears significantly less effective in leukemia eradication and associated with worse overall survival when compared with a higher dose of radiation.

Adjuvant androgen deprivation impacts late rectal toxicity after conformal radiotherapy of prostate carcinoma

To evaluate whether androgen deprivation impacts late rectal toxicity in patients with localised prostate carcinoma treated with three-dimensional conformal radiotherapy. One hundred and eighty-two consecutive patients treated with 3DCRT between 1995 and 1999 at our Institution and with at least 12 months follow-up were analysed. three-dimensional conformal radiotherapy consisted in 70-76 Gy delivered with a conformal 3-field arrangement to the prostate+/-seminal vesicles. As part of treatment, 117 patients (64%) received neo-adjuvant and concomitant androgen deprivation while 88 (48.4%) patients were continued on androgen deprivation at the end of three-dimensional conformal radiotherapy as well. Late rectal toxicity was graded according to the RTOG morbidity scoring scale. Median follow up is 25.8 (range: 12-70.2 months). The 2-year actuarial likelihood of grade 2-4 rectal toxicity was 21.8+/-3.2%. A multivariate analysis identified the use of adjuvant androgen deprivation (P=0.0196) along with the dose to the posterior wall of the rectum on the central axis (P=0.0055) and the grade of acute rectal toxicity (P=0.0172) as independent predictors of grade 2-4 late rectal toxicity. The 2-year estimates of grade 2-4 late rectal toxicity for patients receiving or not adjuvant hormonal treatment were 30.3+/-5.2% and 14.1+/-3.8%, respectively. Rectal tolerance is reduced in presence of adjuvant androgen deprivation.

Gemcitabine, Cisplatin, and Radiation in Advanced, Unresectable Squamous Cell Carcinoma of the Head and Neck

Alternating chemoradiotherapy was shown by our institution to be superior to standard radiation in patients with nonsurgical squamous cell carcinoma of the head and neck (SCC-HN). Gemcitabine has shown in vitro and in vivo radiosensitizing properties, synergistic activity with cisplatin, and cytotoxic activity against SCC-HN. Thus, the authors tested the feasibility and antitumoral activity of a modified alternating chemoradiotherapy program that includes gemcitabine. Fourteen patients with stage IV (nine patients) or relapsed after surgery (five patients) unresectable SCC-HN were enrolled. None had previously received chemotherapy or radiotherapy. The treatment plan consisted of cisplatin, 20 mg/m2/day, days 1 to 5, weeks 1 and 5, and gemcitabine 800 mg/m2, day 5, weeks 1, 2, 3, and 5, 6, 7. Radiation was administered during weeks 2, 3, and 4 and 6, 7, and 8 with conventional fractionation up to 60 Gy. At the end of the combined therapy, patients had to receive two additional courses of cisplatin, 20 mg/m2/day, and fluorouracil, 200 mg/m2/day, for 5 days every 21 days. All the patients are evaluable for toxicity and 11 for response. Main grade III-IV toxicities and frequencies were: neutropenia (79%), neutropenia with fever (50%), thrombocytopenia (57%), anemia (35%), mucositis (100%), and cutaneous toxicity (14%). Ten patients (71%) had a weight loss greater than 10%. All but two patients needed hospitalization and tube feeding or parenteral nutrition. The median relative dose intensity of gemcitabine actually delivered was 83%. Two patients died 1 month after the end of treatment before the final evaluation. One patient died of sepsis during the additional cisplatin and fluorouracil courses before response assessment. Ten patients reached a complete response (intention to treat: 71%), and 1 patient had a partial response (9%). At a median follow-up of 34 months, the actuarial 3-year progression-free survival and overall survival are 41% and 63%, respectively. The estimated 3-year locoregional control is 70%. Considering the expected poor prognosis of the enrolled patients, this combined regimen showed an impressive antitumoral activity, but the severity of acute local and hematologic toxicity correlated makes the exportation of this regimen unproposable. However, the activity observed warrants the exploration of different, less toxic, chemo-radiotherapy programs including gemcitabine.

Alternating chemoradiotherapy versus partly accelerated radiotherapy in locally advanced squamous cell carcinoma of the head and neck: results from a phase III randomized trial

BACKGROUND

The authors previously have found that in patients with locally advanced squamous cell carcinoma of the head and neck (SCC-HN), alternating chemoradiotherapy (ALT) was superior to low-total-dose conventional radiotherapy alone. The purpose of this randomized trial was to compare the same chemoradiotherapy approach with high-total-dose partly accelerated radiotherapy.

METHODS

During 6 years, 136 consecutive patients with previously untreated unfavorable Stage II or Stage III-IV (International Union Against Cancer) SCC of the oral cavity, pharynx, and larynx were enrolled. They were randomly assigned to chemotherapy consisting of 4 cycles of intravenous cisplatin (20 mg/m(2) of body surface area per day for 5 consecutive days) and 5-fluorouracil (200 mg/m(2) per day for 5 consecutive days; weeks 1, 4, 7, and 10) alternated with three 2-week courses of radiotherapy (20 grays [Gy] per course, 2 Gy per day, 5 days per week; ALT, 70 patients) or to partly accelerated radiotherapy with final concomitant boost technique (75 Gy/40 fractions in 6 weeks; partly accelerated radiotherapy [PA-RT], 66 patients).

RESULTS

At the median follow-up of 60 months (range, 30-102 months), no statistical differences were observed in overall survival, progression free survival, or locoregional control between the 2 treatments. Actuarial 3-year overall survival and progression free survival were 37% and 35%, respectively, in the ALT group and 29% and 27%, respectively, in PA-RT group. The median overall survival and progression free survival were 24 and 15 months, respectively, in the ALT arm and 18 and 11 months, respectively, in PA-RT arm. Actuarial 3-year locoregional control rates were 32% in the ALT group and 27% in the PA-RT group. At multivariate analysis, tumor classification was the only factor that emerged as a significant independent variable affecting overall survival. Patients treated in the PA-RT arm experienced higher Grade 3+ (World Health Organization) acute skin and mucosal reactions than patients in the ALT arm. Moreover, local late mucosal and skin toxicities occurred more often in patients treated with PA-RT.

CONCLUSIONS

This trial failed to disclose statistically significant differences in the outcome of patients treated with either ALT or PA-RT. Therefore, definitive conclusions could not be made. However, acute skin effects and late mucosal and skin toxicities above the clavicles appeared to be significantly lower with chemoradiotherapy.

On the delineation of the gross tumor volume and clinical target volume for head and neck squamous cell carcinomas

Gross tumor volume (GTV) and clinical target volume (CTV) delineation on planning computed tomography (pICT) for head and neck squamous cell carcinomas can be troublesome. We highlight the factors which can be crucial for the radiation oncologist in delineating GTV and CTV on pICT and provide some pratical solutions. Regarding GTV, uncertainties are correlated with transfer of information collected by physical examination and diagnostic radiology to pICT. Moreover, reproducibility of delineation can also be highly variable, particularly when diagnostic imaging quality and pICT quality are poor. Once the prescription has been made, clinical target volume identification on pICT is rarely straightforward. Whereas there are some data about the location of major lymph node stations of the neck, there are no reported guidelines on how to draw subclinical extention of primary head and neck tumors on pICT. Such volumes can be derived from those currently included in simulator films or from those addressed by the surgeon. Some examples are provided. A particular situation is represented by the adjuvant setting, when the primary tumor is removed (by surgery) or reduced (by chemotherapy). In conclusion, this paper shows some major problems associated with identification of GTV and CTV on pICT. Apart from selected cases, the use of pICT for target volume delineation (and thus for field shaping) for head and neck squamous cell carcinoma is still to be considered investigational.