Local tissue electrical parameters predict oral mucositis in HNSCC patients: A diagnostic accuracy double-blind, randomized controlled trial.

Oral Mucositis (OM) is a common adverse effect of head and neck squamous cell carcinoma (HNSCC) treatment. The purpose of this study was to investigate the significance of early changes in tissue electrical parameters (TEPs) in predicting the development of OM in HNSCC patients receiving radiation therapy (RT). The current study combined two study designs. The first was a case-control study. The control group comprised of RT patients who did not receive head and neck RT, and patients with HNSCC who received RT comprised the case group. In the second part of the study, the case group was included in a parallel cohort. A total of 320 patients were assessed for eligibility, and 135 patients were enrolled. Double blinding was performed, and neither the patients nor the care providers knew the measured parameters. The primary outcome was the detection of between-group changes in local TEPs over the follow-up period. The secondary outcome was the appearance of OM grades II, III, or IV and the predictive value of local TEPs in determining the incidence of OM after RT. The variables, impedance module, resistance, reactance, phase angle, and capacitance, were analyzed by the receiver operator curves (ROC). The case and control groups did not differ in demographic and clinical characteristics. Radiation therapy increased the local impedance module, resistance, reactance, and phase angle and reduced the local tissue capacitance in both groups. Evaluation of TEPs in the first week of RT correlated with the development of OM lesions during cancer therapy. ROC analysis showed that local impedance module and resistance presented higher specificity than did other parameters in predicting OM. In conclusion, local tissue electrical parameters measured at the first RT week can be useful tools to predict oral mucositis.

Low-dose chronic lead exposure increases systolic arterial pressure and vascular reactivity of rat aortas.

Chronic lead exposure induces hypertension affecting endothelial function. We investigated whether low-concentration lead exposure alters blood pressure and vascular reactivity, focusing on the roles of NO, oxidative stress, cyclooxygenase-derived vasoconstrictor prostanoids, and the local angiotensin-renin system. Aortic rings from 3-month-old Wistar rats were treated daily with lead acetate (first dose 4mg/100g, subsequent doses 0.05mg/100g, im) or vehicle for 30 days. Treatment increased lead blood levels (12µg/dl), blood pressure, and aortic ring contractile response to phenylephrine (1nM-100mM). Contractile response after L-NAME administration increased in both groups but was higher after lead treatment. Lead effects on Rmax decreased more after apocynin and superoxide dismutase administration compared to control. Indomethacin reduced phenylephrine response more after lead treatment than in controls. The selective COX-2 inhibitor NS398, thromboxane A2/prostaglandin H2 receptor antagonist SQ 29,548, TXA2 synthase inhibitor furegrelate, EP1 receptor antagonist SC 19220, and ACE inhibitor and AT1 receptor antagonist losartan reduced phenylephrine responses only in vessels from lead-treated rats. Basal and stimulated NO release was reduced and local O2(-) liberation increased in the lead-treated group compared to controls. eNOS, iNOS, and AT1 receptor protein expression increased with lead exposure, but COX-2 protein expression decreased. This is the first demonstration that blood Pb(2+) (12µg/dl) concentrations below the WHO-established values increased systolic blood pressure and vascular phenylephrine reactivity. This effect was associated with reduced NO bioavailability, increased reactive oxygen species production, increased participation of COX-derived contractile prostanoids, and increased renin-angiotensin system activity.

Cadmium exposure induces vascular injury due to endothelial oxidative stress: the role of local angiotensin II and COX-2.

Cadmium is an environmental pollutant that is closely linked with cardiovascular diseases, such as atherosclerosis and hypertension. Moreover, cadmium can induce an increase in oxidative stress. One of the main sites affected by oxidative stress is the aorta, which consequently develops atherosclerosis. However, there are few reports demonstrating aortic effects induced by small concentrations of cadmium that are similar to those found in the blood resulting from occupational exposure. Furthermore, several studies have reported on chronic cadmium exposure, and the results of these studies may have been influenced by the secondary effects induced by this metal, such as hypertension. Therefore, we investigated the effects of acute cadmium exposure on the vascular reactivity to phenylephrine of aortic rings isolated from male Wistar rats. Cadmium increased phenylephrine reactivity without changing the vasorelaxation induced by acetylcholine and sodium nitroprusside. Endothelial damage or incubation with L-NAME shifted the phenylephrine concentration-response curves leftward in arteries incubated with or without cadmium, but the curves were shifted to a lesser degree after cadmium incubation. Enalapril, losartan, the nonselective COX inhibitor indomethacin, the TXA(2) synthase inhibitor furegrelate, the selective COX-2 inhibitor NS 398, the TP receptor antagonist SQ 29.548, the EP1 receptor antagonist SC 19.220, superoxide dismutase, and the NADPH oxidase inhibitor apocynin partially reverted the cadmium-induced effects on the reactivity to phenylephrine. Cadmium exposure increased vasoconstrictor activity by reducing NO bioavailability owing to the increased production of ROS by NADPH oxidase. The results of the tested cadmium concentration, which is below the reference values, suggest that acute cadmium exposure may induce vascular injury through endothelial oxidative stress. These data contribute to the evidence indicating that cadmium is a high risk to public health.