RESUMEN
Accumulating evidence indicates that central blood pressure (CBP) is a better cardiovascular risk predictor than brachial blood pressure (BP). Although more additional benefits of CBP-based treatment above usual hypertension treatment are to be demonstrated, the demand for implementing CBP assessment in general clinical practice is increasing. For this, the measurement procedure must be noninvasive, easy to perform, and cost- and time-efficient. Therefore, oscillometric devices with the possibility to assess CBP seem the best option. Recently, such an oscillometric BP monitor, the Microlife WatchBP Office Central, was developed, which demonstrated its high accuracy in a validation study against invasive BP measurement. Calibration errors of this device are limited because the procedure is automated, standardized, and performed at the same place of and within 30 s from pulse wave assessment. The transformation from the peripheral pulse wave to CBP is done by means of an individual-based pulse wave analysis according to a theory of arterial compliance and wave reflections. In addition, the device has demonstrated to enable a more reliable diagnosis of hypertension by CBP than by peripheral BP, with a lower frequency of over- and underdiagnosis. Altogether, the available clinical evidence suggests that the Microlife WatchBP Office Central fulfills the criteria for general clinical use.
RESUMEN
BACKGROUND: Nasopharyngeal carcinoma (NPC) harbors a higher metastatic potential than other head and neck cancers. In order to seek a possible surrogate marker for early detection of recurrent or metastatic disease, we tested the feasibility of cytokeratin-19 (CK-19)-nested reverse-transcription polymerase chain reaction (RT-PCR) for detecting circulating tumor cells in NPC patients. METHODS: Two tubes of blood were sequentially collected in individual draws from 7 NPC patients and 15 healthy persons. Total ribonucleic acid (RNA) was extracted from blood cells and treated with deoxyribonuclease. The RNA was then subjected to RT and nested PCR with specific CK-19 primers. The reaction products were run on an agarose gel and visualized under UV light. The sequences of the products were determined using an ABI377 automatic sequencer. RESULTS: Among the 7 NPC cases, 4 cases presented CK- 19 expression with 2 in both tubes, 1 in the first tube, and 1 in the second tube. In the control group, 8 of 15 cases also presented CK-19 expression with 6 in both tubes and 2 in the second tube resulting in a 53.3% false-positive rate. Incidentally, an aberrant splicing product lacking exon 4 of CK-19 messenger RNA was discovered. CONCLUSION: Results of the present study indicate that the CK-19-nested RT-PCR is not suitable for detecting circulating tumor cells in NPC patients because of a high false-positive rate in the control group. The reason for the high rate of false-positives may be attributed to pseudogenes, different blood cell separation methods, or illegitimate expression of CK-19 in blood cells.
