高效液相色谱法测定血浆中洛美沙星浓度及其在人体内药代动力学

建立了人血浆洛美沙星的反相离子对高效液相色谱测定方法。该法简便易行,精密度好,方法回收率95～102%,日内、日间RSD为2.1～7.8%,血药浓度在0.125～5.012 μg/ml范围内呈线性关系,相关系数0.9998,当S/N=2时,最小检测浓度为25 ng/ml。健康志愿者口服400 mg洛美沙星,药代动力学过程符合一室模型,消除相半衰期为5.5 h。     

External (combination) rhinoplasty approach for trans-sphenoidal adenectomy

The external (combination) rhinoplasty approach and the sublabial approach to trans-sphenoidal adenomectomy have been used at this institution for seven years. A summary of experience with the external (combination) rhinoplasty technique in 10 patients is reported; and a comparison is made between this approach and the sublabial approach in 12 patients. Advantages unique to this approach are: the distance to the sphenoid sinus is decreased allowing greater ease of instrumentation, the Hardy speculum may be opened widely to increase exposure, uniquely this allows synchronous cosmetic or reconstructive septorhinoplasty, and this technique is also invaluable for revision surgery--especially when septal cartilage has been removed by a previous sublabial approach. Disadvantages of this technique are the external incision across the columella, which leaves an imperceptible scar of no clinical significance, and postoperative nasal tip edema, which resolves with time.     

Coordination environment of the active-site metal ion of liver alcohol dehydrogenase.

The coordination environment of the catalytically active metal ion of horse liver alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) has been investigated by electron paramagnetic resonance (EPR) methods with use of the active-site-specific Co2+-reconstituted enzyme. The EPR absorption spectrum of the metal-substituted enzyme is characteristic of a rhombically distorted environment. The spectrum of the enzyme--NAD+ complex shows approximate axial symmetry of the metal ion site, indicating that binding of the coenzyme induces a structural alteration in the active-site region. This environment is not significantly altered further by binding of the competitive inhibitor pyrazole. To assign the coordination number of the active-site metal ion, the zero-field splitting was determined on the basis of the temperature dependence of the spin--lattice relaxation of the Co2+ ion. The zero-field splitting energies are approximately 9 cm-1 for the free Co2+-reconstituted enzyme and approximately 46 and approximately 47 cm-1 for the enzyme--NAD+ and enzyme--NAD+--pyrazole complex, respectively. On the basis of studies of structurally defined small molecule complexes, these values are compatible with a tetracoordinate metal ion in the active site of the free enzyme but a pentacoordinate metal ion in the binary enzyme--NAD+ complex and in the ternary enzyme--NAD+--inhibitor complex and, therefore, presumably also in the catalytically active ternary enzyme--NAD+--alcohol complex formed in the course of alcohol oxidation.     

Temporal stability and precision of ventricular defibrillation threshold data.

Over 200 measurements of the minimum damped sinusoidal current and energy for transchest electrical ventricular defibrillation (ventricular defibrillation threshold) were made to determine the stability and precision of threshold data in 15 pentobarbital-anesthetized dogs. Threshold was determined by repeated trials of fibrillation and defibrillation with successive shocks of diminishing current, each 10% less than that of the preceding shock. The lowest shock intensity that defibrillated was defined as threshold. In three groups of five dogs each, threshold was measured at intervals of 60, 15, and 5 min over periods of 8, 5, and 1 h, respectively. Similar results were obtained for all groups. There was no significant change in mean threshold current with time. Owing to a decrease in transchest impedance, threshold delivered energy decreased by 10% during the first hour of testing. The standard deviations for threshold peak current and delivered energy in a given animal were 11% and 22% of their respective mean values. Arterial blood pH, Pco2, and Po2 averaged change of pH, PCO2 and PO2 were not significantly different from zero. The data demonstrate that ventricular defibrillation threshold is a stable physiological parameter that may be measured with reasonable precision.     

Fasting plasma zeaxanthin response to Fructus barbarum L. (wolfberry; Kei Tze) in a food-based human supplementation trial

Age-related macular degeneration (AMD) is a common disorder that causes irreversible loss of central vision. Increased intake of foods containing zeaxanthin may be effective in preventing AMD because the macula accumulates zeaxanthin and lutein, oxygenated carotenoids with antioxidant and blue light-absorbing properties. Lycium barbarum L. is a small red berry known as Fructus lycii and wolfberry in the West, and Kei Tze and Gou Qi Zi in Asia. Wolfberry is rich in zeaxanthin dipalmitate, and is valued in Chinese culture for being good for vision. The aim of this study, which was a single-blinded, placebo-controlled, human intervention trial of parallel design, was to provide data on how fasting plasma zeaxanthin concentration changes as a result of dietary supplementation with whole wolfberries. Fasting blood was collected from healthy, consenting subjects; fourteen subjects took 15 g/d wolfberry (estimated to contain almost 3 mg zeaxanthin) for 28 d. Repeat fasting blood was collected on day 29. Age- and sex-matched controls (n 13) took no wolfberry. Responses in the two groups were compared using the Mann-Whitney test. After supplementation, plasma zeaxanthin increased 2.5-fold: mean values on day 1 and 29 were 0.038 (sem 0.003) and 0.096 (sem 0.009) micromol/l (P<0.01), respectively, for the supplementation group; and 0.038 (sem 0.003) and 0.043 (sem 0.003) micromol/l (P>0.05), respectively, for the control group. This human supplementation trial shows that zeaxanthin in whole wolfberries is bioavailable and that intake of a modest daily amount markedly increases fasting plasma zeaxanthin levels. These new data will support further study of dietary strategies to maintain macular pigment density.     

Retroperitoneal perforation of the duodenum from biliary stent erosion

Endoscopically placed biliary stents have supplanted surgical decompression as the preferred treatment option for patients with obstructive jaundice from advanced pancreatic cancer. An unusual complication of indewelling biliary stents is duodenal perforation into the retroperitoneum. We describe the case of a patient with end-stage pancreatic cancer who presented with an acute abdomen from erosion of a previously placed bile duct stent through the wall of the second portion of the duodenum. Although our patient presented with advanced symptoms, clinical presentations can vary from mild abdominal discomfort and general malaise to overt septic shock. Definitive diagnosis is best made with computed tomography (CT) imaging, which can detect traces of retroperitoneal air and fluid. Treatment options vary from nonoperative management with antibiotics, bowel rest, and parenteral alimentation in the most stable patients to definitive surgery with complete diversion of gastric contents and biliary flow from the affected area in patients with clinical symptoms or radiologic evidence suggesting extensive contamination. Complications of management can include duodenal fistulization, residual retroperitoneal or intrabdominal abscess, and ongoing sepsis. This report highlights the salient issues in the presentation, diagnosis, and modern management of patients with this rare complication of indwelling biliary stents.     

Is Minimal Access Surgery for Cancer Associated with Immunologic Benefits?

Minimal-access surgical techniques have been shown to be beneficial to patients in terms of shorter convalescence, reduced pain, and improved cosmesis. Although systemic immune function is better preserved following laparoscopic procedures when compared with their respective open approaches, CO₂ pneumoperitoneum may significantly affect local (i.e., infra-abdominal) cellular immunity by reducing regional macrophage function. Results to date are conflicting with regard to the impact of closed and open methods on intraabdominal immunity. Impaired cellular immunity after CO₂ pneumoperitoneum may have significant undesirable intra-abdominal effects on tumor surveillance after oncological surgery; however, at present, there is no clinical evidence to support this position. The VATS techniques avoid the use of CO₂ insufflation, which may offer some advantages from the immune function perspective over laparoscopic procedures accomplished with CO₂ pneumoperitoneum. Better preservation of early postoperative cellular immune function and attenuated disturbance in the inflammatory mediators are likely contributing factors to the clinical benefits that follow laparoscopic surgery and VATS. Larger multi-center randomized trials are needed to confirm the potential benefits of minimal-access surgery on patient survival after cancer surgery. Future research should focus on the effects of minimal-access surgery on other mediators (such as MMP-9, IGFBP-3, IL-12, IL-17, and IL-23) that may be important in tumor cell dissemination, deposition, and propagation in the early postoperative period. Furthermore, additional searches for other factors or mediators, heretofore unrecognized, should be carried out. Such studies will, we hope, increase our knowledge and understanding of the impact of surgery on immune and other physiologic functions.