[Repeated radiation dose effect and DNA repair: Importance of the individual factor and the time interval between the doses]. / Effets de répétitions de doses d'irradiation et réparation de l'ADN : importance du facteur individuel et de l'intervalle de temps entre les doses.

The dose fractionation effect is a recurrent question of radiation biology research that remains unsolved since no model predicts the clinical effect only with the cumulated dose and the radiobiology of irradiated tissues. Such an important question is differentially answered in radioprotection, radiotherapy, radiology or epidemiology. A better understanding of the molecular response to radiation makes possible today a novel approach to identify the parameters that condition the fractionation effect. Particularly, the time between doses appears to be a key factor since it will permit, or not, the repair of certain radiation-induced DNA damages whose repair rates are of the order of seconds, minutes or hours: the fractionation effect will therefore vary according to the functionality of the different repair pathways, whatever for tumor or normal tissues.

[Radiation-induced sarcoma of the head and neck]. / Sarcomes radio-induits de la tête et du cou.

INTRODUCTION: Radiation-induced sarcoma (RIS) of the head and neck is a late and rare complication of cancer treatment by radiation therapy. It occurs mostly within the limits of the irradiated area. Its incidence is increasing and related to an improved survival rate of treated patients. But it does not rule out the use of radiotherapy in the treatment of this cancer. OBSERVATION: We report two cases of sarcoma having appeared in the irradiated area, in patients treated by adjuvant radiotherapy for head and neck neoplasm. DISCUSSION: The prognosis for this sarcoma depends mainly on how early the diagnosis is made and the quality of surgical resection. Adjuvant chemotherapy or radiotherapy can be considered. Ongoing research on the expression of RIS genes could soon lead to new treatments.

Transoral robotic surgery for head and neck cancer: a series of 17 cases.

OBJECTIVES: Transoral robotic surgery (TORS) is an innovative surgical technique indicated for resection of selected head and neck cancers. The authors report their experience and discuss the indications, advantages and disadvantages of this technique. MATERIALS AND METHODS: Seventeen patients were operated by TORS in the Limoges University Hospital ENT department between March 2010 and January 2011. RESULTS: Tumour sites were the aryepiglottic fold (n=3), piriform sinus (n=2), lateral pharyngeal wall (n=3), posterior pharyngeal wall (n=2), base of tongue (n=3), vallecula (n=1), epiglottis (n=2) and arytenoid (n=2). One patient had two primary sites treated by TORS. This series comprised two stage I (11.7%), seven stage II (41.2%), six stage III (35.4%) and two stage IVa tumours (11.7%). Mean TORS set-up and operating times were 20.5 and 39.7 minutes, respectively. No major intraoperative complication was observed. One patient was reoperated on D5 for bleeding. Fifteen patients had clear surgical margins. Swallowing was restored on D2 for nine patients. The mean length of hospital stay was 10 days. Seven patients received adjuvant radiotherapy, seven patients were treated by chemoradiotherapy and three patients were submitted to simple clinical surveillance. CONCLUSION: TORS appears to provide new treatment options for head and neck cancers by extending the indications for endoscopic resection for selected cases of head and neck cancers. It allows effective cancer resection under excellent operating conditions with low morbidity and improved functional recovery. This new treatment modality needs to be evaluated in relation to other open surgery, endoscopic laser and chemoradiotherapy techniques.

A direct anatomical study of additional renal arteries in a Colombian mestizo population.

Traditional anatomy describes each kidney as receiving irrigation from a single renal artery. However, current literature reports great variability in renal blood supply, the number of renal arteries mentioned being the most frequently found variation. Such variation has great implications when surgery is indicated, such as in renal transplants, uroradiological procedures, renovascular hypertension, renal trauma and hydronephrosis. This article pretends to determine the frequency of additional renal arteries and their morphological expression in Colombian population in a cross-sectional study. A total of 196 of renal blocks were analysed from autopsies carried out in the Bucaramanga Institute of Forensic Medicine, Colombia; these renal blocks were processed by the injection- corrosion technique. The average age of the people being studied was 33.8 +/- 15.6 years; 85.4% of them were male and the rest female. An additional renal artery was found in 22.3% of the whole population and two additional ones were found in 2.6% of the same sample. The additional renal artery was most frequently found on the left side. The additional artery arose from the aorta's lateral aspect (52.4%); these additional arteries usually entered the renal parenchyma through the hilum. No difference was established according to gender. Nearly a third of the Colombian population presents one additional renal artery and about 3% of the same population presents two additional renal arteries. Most of them reached the kidney through its hilar region.

Electrophysiology of posterior, NaCl-absorbing gills of Chasmagnathus granulatus: rapid responses to osmotic variations.

In the present study, the influence of short-term osmotic variations on some electrophysiological properties related to NaCl absorption across posterior gills of Chasmagnathus granulatus was investigated. The transepithelial potential difference (V(te)) of isolated and perfused gills increased significantly when hyposmotic saline (699 mosmol l(-1)) was used instead of isosmotic solution (1045 mosmol l(-1)). A reduction of the concentration of Na(+) or Cl(-) at constant osmolarity did not produce any change in V(te). Transepithelial short-circuit current (I(sc)) and conductance (G(te)), measured with split gill lamellae mounted in a modified Ussing chamber, also increased after changing to hyposmotic salines (I(sc): from -89.0+/-40.8 microA cm(-2) to -179.3+/-37.0 microA cm(-2); G(te): from 40.5+/-16.9 mS cm(-2) to 47.3+/-15.8 mS cm(-2)). The observed effects of reduced osmolarity were fast, reversible and gradually dependent on the magnitude of the osmotic variation. The activity of the Na(+)/K(+)-ATPase increased significantly after perfusion with hyposmotic saline, from 18.73+/-6.35 micromol P(i) h(-1) mg(-1) to 41.84+/-14.54 micromol P(i) h(-1) mg(-1). Theophylline maintained part of the elevated V(te) induced by hyposmotic saline, suggesting that an increased cellular cyclic AMP level is involved in the response to reduced osmolarity. In summary, the results indicate that the hemolymph osmolarity regulates active transbranchial NaCl absorption by modulating the activity of the basolateral Na(+)/K(+)-ATPase and by changing a conductive pathway, probably at the apical membrane.