Heart rate variability during abdominal surgical manipulation under general and epidural anesthesia

Anesthesiologists occasionally encounter bradycardia during abdominal surgery and recognize the phenomenon as a vagal reflex. The presence of bradycardia implies efferent vagal dominance in the autonomic nervous system during this vagal reflex. In this study, we investigated the effect of abdominal surgical manipulation on autonomic nervous activity, using heart rate variability analysis. Abdominal surgical manipulation decreased the heart rate and enhanced not only the high-frequency power (0.15–0.4 Hz) but also the low-frequency power (0.04–0.15 Hz) calculated from the power spectral density of heart rate variability. Our results suggest that both vagal tone and sympathetic tone could be activated during the vagal reflex caused by abdominal surgical manipulation.     

Dexmedetomidine and hydroxyzine synergistically potentiate the hypnotic activity of propofol in mice

Purpose

Investigation into the characteristics of anesthetic interactions may provide clues to anesthesia mechanisms. Dexmedetomidine, an ??₂-adrenergic receptor agonist, has become a popular sedative in intensive care, and hydroxyzine, a histamine receptor antagonist, is well known as a tranquilizing premedication for anesthesia. However, no experimental or pharmacological evaluation has been reported concerning their combination with propofol. Thus, we studied their combined effect with a hypnotic dose of propofol in ddY mice.

Methods

Male adult mice were intravenously administered either dexmedetomidine (30???g/kg) or hydroxyzine (5?mg/kg) with propofol (3.75?C10?mg/kg) to induce hypnosis, defined as a loss of the righting reflex (LRR). Other mice were intravenously administered propofol, dexmedetomidine (300???g/kg), or hydroxyzine (50?mg/kg) alone, and subsequent behavioral changes were observed. The 50% effective dose (ED₅₀) for LRR was calculated, and the duration of LRR was determined.

Results

The hypnotic dose of propofol was 9.95?±?1.04?mg/kg (ED₅₀?±?SEM) without combination. Dexmedetomidine and hydroxyzine reduced the ED₅₀ of propofol to 5.32?±?0.57 and 5.63?±?0.57?mg/kg, respectively. Coadministration of dexmedetomidine significantly extended LRR duration compared with propofol alone, whereas hydroxyzine significantly shortened LRR duration. A maximal dose of dexmedetomidine or hydroxyzine alone did not induce hypnosis.

Conclusions

Dexmedetomidine and hydroxyzine demonstrated no hypnotic action alone; however, their coadministration potentiated the hypnotic activity of propofol. Although reduction in the dose of propofol was similar, only dexmedetomidine prolonged the duration of hypnosis.     

Prognostic significance of loss of a chromosome 17p and p53 gene mutations in blast crisis of chronic myelogenous leukaemia

SUMMARY. In 31 cases of chronic myelogenous leukaemia (CML) we examined the prognostic significance of chromosomal loss of a 17p and p53 mutations at the onset of blast crisis (BC). p53 mutations were closely related to a shortened survival in CMLBC ( P < 0.005 by the logrank test), whereas loss of a 17p by itself was not a poor prognostic indicator. The prognostic significance of loss of a 17p, however, emerged when combined with its predominance in the metaphases analysed. This predominance might easily and rapidly be screened by polymerase chain reaction-based analysis in about half of the cases.     

Docetaxel suppresses invasiveness of head and neck cancer cells in vitro

The combination of docetaxel, cisplatin, and fluorouracil significantly enhances the survival of head and neck cancer patients compared to cisplatin and fluorouracil. We hypothesized that docetaxel may affect invasiveness of the head and neck cancer cells in addition to its tumor‐killing effect. Two different head and neck cancer cell lines (HEp‐2 and Ca9‐22) were treated with docetaxel at IC₁₀ and IC₅₀ concentrations. Cell migration and invasive growth was evaluated by wound healing assay and three‐dimensional (3D) culture of multicellular tumor spheroids, respectively. Expression levels of possible downstream effectors for cell migration/invasiveness were measured by immunoblotting in conditions with or without docetaxel. Docetaxel, but not cisplatin, suppressed filopodia formation compared with no treatment (control) condition. Consistent with this, docetaxel suppressed two‐dimensional (2D) cell migration and 3D cell invasion compared with control or cisplatin. Only docetaxel treated cells exhibited thick tubulin bundle and had lower activity of Cdc42, a member of the Rho family of small GTPases. In conclusion, Docetaxel treatment suppressed migration and invasiveness of head and neck cancer cells in vitro, which is likely to be mediated by regulating Cdc42 activity. (Cancer Sci 2010; 00: 000–000)