Correlation between bithermal caloric test results and vestibular evoked myogenic potentials (VEMPs) in normal subjects.

UNLABELLED: Bithermal caloric testing and vestibular evoked myogenic potentials (VEMPs) are both diagnostic tools for the study of the vestibular system. The first tests the horizontal semicircular canal and the second evaluates the saccule and lower vestibular nerve. The results of these two tests can therefore be expected to be correlated. The aim of this study was to compare bithermal caloric test results with VEMP records in normal subjects to verify whether they are correlated. MATERIAL AND METHOD: A prospective study was conducted in 60 healthy subjects (30 men and 30 women) who underwent otoscopy, pure tone audiometry, bithermal caloric testing and VEMPs. From the caloric test, we assessed the presence of possible vestibular hypofunction, whether there was directional preponderance and reflectivity of each ear (all based on both slow phase velocity and nystagmus frequency). The analysed VEMPs variables were: p1 and n1 latency, corrected amplitude, interaural p1 latency difference and p1 interaural amplitude asymmetry. We compared the reflectivity, hypofunction and directional preponderance of the caloric tests with the corrected amplitudes and amplitude asymmetries of the VEMPs. No correlations were found in the different comparisons between bithermal caloric testing results and VEMPs except for a weak correlation (p = 0.039) when comparing preponderance based on the number of nystagmus in the caloric test and amplitude asymmetry with 99 dB tone burst in the VEMPs test. The results indicate that the two diagnostic tests are not comparable, so one of them cannot replace the other, but the use of both increases diagnostic success in some conditions.

Beta-adrenergic receptors in cancer: therapeutic implications.

The beta-adrenergic receptors transduce catecholamine signals to the G protein, which through a cascade of chemical reactions in cells generates highly specific parallel signals. The beta2-adrenergic receptor (ADRB2) is the most involved in the carcinogenic processes. Previous studies have determined the relationship of ADRB2 with various aspects related to cancer. Basically, it seems to be related with cell proliferation and apoptosis, chemotaxis, development of metastasis and tumor growth, and angiogenesis. The purpose of this review is to update the implications of these receptors in the pathogenesis of cancer and study the possible application of agonist drugs and/or antagonists in antitumor therapy.

Measurement of ATP6V1C1 expression in brush cytology samples as a diagnostic and prognostic marker in oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity. Brush cytology has reemerged as a molecular tool for diagnosing this cancer. ATP6V1C1, one of the main genes regulating V-ATPase activity, has been implicated in metastasis and multiple drug resistance. The aim of this study was to measure ATP6V1C1 expression levels in OSCC and to evaluate the value of this test in the diagnosis and prognosis of OSCC. RESULTS: The differences in ATP6V1C1 expression between patients and controls were statistically significant (Mann-Whitney U test = 26, p < 0.001). Receiver operating characteristic (ROC) curve analysis showed an area under the curve of 0.9476, with the following diagnostic indices: sensitivity, 81.25%, specificity, 93.75%; accuracy, 87.50%; positive predictive value, 92.86%; negative predictive value, 83.33%; positive likelihood ratio, 30; and negative likelihood ratio, 0.06. MATERIAL AND METHODS: Patients with OSCC and a control group of healthy individuals were studied. The clinical and demographic variables analyzed included age, sex, smoking, tumor location and tumor stage. Brush cytology samples were obtained using a cytology brush and analyzed by real-time quantitative polymerase chain reaction for ATP6V1C1 expression. CONCLUSIONS: It was confirmed that ATP6V1C1 levels were significantly higher in patients with OSCC than in healthy controls, with expression increasing with higher tumor stage. ROC analysis showed that the measurement of ATP6V1C1 expression levels is a highly sensitive and specific diagnostic method.

Multidrug resistance in oral squamous cell carcinoma: The role of vacuolar ATPases.

Resistance to chemotherapy agents is the main reason for treatment failure in patients with cancer. Multidrug resistance (MDR) is the primary mechanism that leads to the acquisition of the multiresistant phenotype through the overexpression of drug efflux transporters such as the P-glycoprotein (Pgp), encoded by the MDR1 gene, at the plasma membrane. Other molecules that have been implicated in drug resistance include multidrug resistance-associated proteins, glutathione S-transferase-pi, and DNA topoisomerase II. These molecules, however, cannot fully explain MDR in oral squamous cell carcinoma. Vacuolar ATPase (V-ATPase), which is largely responsible for regulating acidity in the microenvironment of solid tumors (and hence interfering with the absorption of chemotherapy drugs), seems to be the most important molecule involved in MDR in such tumors. Specific V-ATPase inhibitors, thus, may be useful, not only as coadjuvants in antitumor treatments but also as a mechanism for controlling resistance to antitumor drugs.