Continuous hyperfractionated accelerated radiotherapy with/without mitomycin C in head and neck cancer

PURPOSE: To evaluate the effect of mitomycin C to an accelerated hyperfractionated radiation therapy. The aim was to test a very short schedule with/without mitomycin C (MMC) with conventional fractionation in histologically verified squamous cell carcinoma of the head and neck region. METHODS AND MATERIALS: From October 1990 to December 1996, 188 patients entered the trial. Tumors originated in the oral cavity in 54, oropharynx in 82, larynx in 20, and hypopharynx in 32 cases, respectively. Patients' stages were predominantly T3 and T4 (158/188, 84%) and most patients had lymph node metastases (144/188, 77%) at diagnosis. Only 22 patients were female, 166 were male, the median age of patients was 57 years (range 34 to 76 years). Patients were randomized to one of the following three treatment options: conventional fractionation (CF) consisting of 70 Gy in 35 fractions over 7 weeks (65 patients) or continuous hyperfractionated accelerated radiation therapy (V-CHART; 62 patients) or continuous hyperfractionated accelerated radiation therapy with 20 mg/sqm MMC on day 5 (V-CHART + MMC; 61 patients). By the accelerated regimens, the total dose of 55.3 Gy was delivered within 17 consecutive days, by 33 fractions. On day 1, a single dose of 2.5 Gy was given, from day 2 to 17 a dose of 1.65 Gy was delivered twice: the interfraction interval was 6 hours or more. RESULTS: Mucositis was very intense after accelerated therapy, most patients experiencing a grade III/IV reaction. The mucosal reaction did not differ whether MMC was administered or not. Patients treated by accelerated fractionation experienced a confluent mucosal reaction 12-14 days following start of therapy and recovered (no reaction) within 6 weeks. The skin reaction was not considered different in the three treatment groups. Those patients treated with additional chemotherapy experienced a grade III/IV hematologic toxicity in 12/61 patients. Initial complete response (CR) was recorded in 43% following CF, 58% after V-CHART, and 67% after V-CHART + MMC, respectively (p < 0.05). Actuarial survival (Kaplan-Meier) was significantly improved in the combined treated patients. Local tumor control was 28%, 32%, and 56% following CF, V-CHART, and V-CHART + MMC, respectively (p < 0.05). CONCLUSION: We conclude that our continuous hyperfractionated accelerated radiation therapy regimen is equal to conventional fractionation, suggesting that by shortening the overall treatment time from 7 weeks to 17 days a reduction in dose from 70 Gy to 55.3 Gy is possible, with maintenance of local tumor control rates. The administration of MMC to the accelerated regimen is tolerable and improves the outcome for patients significantly.     

New epidemiological aspects of dengue

Since the 1940s, the dengue epidemics occur more and more often in the Pacific islands with an increased severity. For example, in New Caledonia, outbreaks of dengue-like diseases have been reported since the end of the last century but the first epidemic due to an identified virus occurred in 1942-1943 and was caused by the DEN-1 type. The next, due to the DEN-2 type, was reported thirty years later, in 1972-1973. After that, three outbreaks burst between 1975 and 1990, caused successively by dengue types 1, 4 and 3 but from 1985, human strains of different types were isolated at the same time. The vector control measures, mainly aerial ULV spraying had a variable efficacy. The most important vector was Aedes aegypti but dengue virus strains were also isolated from other mosquito species (Aedes vigilax, Culex annulirostris, C. bitaeniorhynchus, Coquillettidia xanthogaster); their role in the interhuman transmission of dengue was not demonstrated. In New Caledonia, the development of international travels, an extension of suburbs and an increased insecticide resistance of Ae. aegypti are the obvious causes of the problem but an unknown transmission cycle, involving different hosts and vectors may also be suspected.     

Limitations of quantitative research in the study of structural adjustment

Sociologists and, more recently, critical medical anthropologists have been arguing for a refocusing of the analysis of health and health care towards a perspective which considers the broader global political economy. In the context of the debt crisis and IMF/World Bank-inspired structural adjustment policies, the political economy theoretical perspective is becoming even more relevant in the analysis of health underdevelopment in many 'Third World' countries. This study focuses on the direct and indirect effects of the Jamaican debt crisis and structural adjustment programmes on health care services and health standards. In this paper it is argued that there are methodological problems using quantitative data when studying the effects of structural adjustment. In addition to providing a limited account of the effects, it is argued that the basic problem is a matter of the availability and reliability of the quantitative data in many 'Third World' countries. It is argued that some of these problems could be overcome by the application of qualitative micro-level analysis. This type of methodology is important to ascertain the effects of global processes at the grass roots level and to gain insights into what those working in the health sector are experiencing and what they perceive as the effects, if any, of structural adjustment policies. This has often been missing from the impersonal accounts offered by quantitative research on the subject to date.     

Practical considerations on the use of the Charlson comorbidity index with administrative data bases

To develop a measure of the burden of comorbid disease from the MED-ECHO data base (Québec), the so-called Charlson index was adapted to International Classification of Disease (ICD-9) codes. The resulting comorbidity index was applied to the study of inpatient death in 33,940 patients with ischemic heart disease. Multiple logistic regression was used to relate inpatient death to its predictors, including gender, principal diagnosis, age, and the comorbidity index. Various transformations of the comorbidity score were performed, and their effect on the predictive accuracy was assessed. The comorbidity index was constantly and strongly associated with death. From a statistical viewpoint, the best results were obtained when the index was transformed into four dummy independent variables (the area under the receiver-operating curve is then 0.87). In a validation analysis performed on 1990-1991 MED-ECHO data (36,012 admissions with ischemic heart disease), the comorbidity index has the same statistical properties. We conclude that the Charlson index may be an efficient approach to risk adjustment from administrative data bases, although it should be tested on other conditions.     

Special features of synthesis of a heat-resistant glass-ceramic coating

In order to protect Ni–Cr alloys from high-temperature corrosion, a new heat-resistant glass-ceramic coating was developed with a glass matrix synthesized on the basis of a composite R _x O–Al₂O₃–SiO₂–TiO₂ (R–Li^–, Na⁺, K⁺, Mg²⁺, Ca²⁺, Ba²⁺) system. The special features of the formation of crystalline phases in the glasses in heat treatment and the optimum regime for the formation of a glass ceramic structure are described.Translated from Steklo i Keramika, No. 3, pp. 30–32, March, 1996.     

Far-infrared pump-probe measurement of the lifetime of the 2p−1 shallow donor level in n-GaAs

The low temperature lifetime of electrons excited in the 2p^?1 donor level of n-GaAs has been studied in a far-infrared pump-probe experiment. The measurement has been carried out using a pulsed far-infrared molecular gas laser working at a wavelength of 292µm, with the sample in a magnetic field of 5.1 T, resonant with the 1s_o?2p^?1 transition. Two FIR pulses are sliced from one FIR-laser pulse by means of optical switching techniques using two Q-switched Nd:YAG lasers. The first pulse is used to saturate the transition, while the second pulse probes the return of the population in the excited state towards thermal equilibrium as a function of the time delay after the excitation pulse. The value of 350±50 ns found for the lifetime falls in line with CW saturation results on materials with other doping concentrations.