糖皮质激素抑制缓激肽引起的PC12细胞外钙内流与蛋白激酶C有关

缓激肽（BK）可引起PC12细胞的[Ca2＋]i；升高，该作用不通过电压敏感性钙通道，而是由G蛋白转导，通过内钙释放和外钙内流引起的。BK的作用可受到皮质疏（B）的快速抑制。本研究利用无钙／再加钙方法，把BK对内钙释放和外钙内流作用分开来进行研究。结果发现：（1）B可以抑制BK引起的外钙内流，对内钙释放影响不明显；（2）B－BSA（牛血清白蛋自偶联的皮质疏）对BK所引起外钙内流的抑制作用与游离的B作用类似；（3）PKC激活剂（PMA）可以模拟，而PKC的抑制剂G66976可以逆转B的抑制作用；（4）百日咳毒素（PTX）预处理可以阻断B抑制BK引起的外钙内流。结果提示：B可能作用在膜受体上，通过PTX敏感的G蛋白-PKC途径抑制BK引起的外钙内流。     

Bacterial growth in secretions and on suctioning equipment of orally intubated patients: a pilot study.

BACKGROUND: Contamination of equipment, colonization of the oropharynx, and microaspiration of secretions are causative factors for ventilator-associated pneumonia. Suctioning and airway management practices may influence the development of ventilator-associated pneumonia. OBJECTIVES: To identify pathogens associated with ventilator-associated pneumonia in oral and endotracheal aspirates and to evaluate bacterial growth on oral and endotracheal suctioning equipment. METHODS: Specimens were collected from 20 subjects who were orally intubated for at least 24 hours and required mechanical ventilation. At baseline, oral and sputum specimens were obtained for culturing, and suctioning equipment was changed. Specimens from the mouth, sputum, and equipment for culturing were obtained at 24 hours (n=18) and 48 hours (n=10). RESULTS: After 24 hours, all subjects had potential pathogens in the mouth, and 67% had sputum cultures positive for pathogens. Suctioning devices were colonized with many of the same pathogens that were present in the mouth. Nearly all (94%) of tonsil suction devices were colonized within 24 hours. Most potential pathogens were gram-positive bacteria. Gram-negative bacteria and antibiotic-resistant organisms were also present in several samples. CANCLUSIONS: The presence of pathogens in oral and sputum specimens in most patients supports the notion that microaspiration of secretions occurs. Colonization is a risk factor for ventilator-associated pneumonia. The equipment used for oral and endotracheal suctioning becomes colonized with potential pathogens within 24 hours. It is not known if reusable oral suction equipment contributes to colonization; however, because many bacteria are exogenous to patients' normal flora, equipment may be a source of cross-contamination.     

Perfluorooctylbromide (PFOB) as a vitreous substitute in non-human primates

We evaluated the toxicity of perfluorooctylbromide in the primate eye as a short-term postoperative vitreous substitute. Four eyes of 4 African green monkeys underwent complete vitrectomy and vitreous replacement with 1.5–2.0 ml of PFOB. One additional animal received BSS as a control vitreous substitute in one eye. Animals were examined twice weekly for clarity and consistency of the vitreous replacement substance. Anterior segment and lenses remained clear in all eyes, although in the immediate postoperative period one eye became inflamed and had a culture-negative vitritis. The other eyes showed a minimal anticipated postoperative vitreous inflammation. Emulsification of the PFOB began within 3 days of injection and progressed up to 3 weeks, precluding fundus examination and fluorescein angiography after 2 weeks. Eyes were enucleated and light microscopy performed at 2 days, 10 days, 33 days, and 45 days. No toxic effects to the retinal cells were detectable by histological examination, but perivasculitis of retinal vessels was noted at 45 days. Indirect examination was normal up to 10 days; thereafter, the fundus view was obscured by the emulsified PFOB. Because of cellular migration into the vitreous cavity and retinal perivasculitis, observed histologically, PFOB seems most suitable for intraoperative rather than postoperative use.Supported in part by U.S. Public Health Service grants EY07541 and EY02377 and NEI1F32EY06193-03 from the National Eye Institute, National Institutes of Health, Bethesda, MD, USA.     

In vitro and in vivo antitumor activity of oridonin nanosuspension

The aim of the present study was to evaluate the antitumor activity of an oridonin (ORI) nanosuspension relative to ORI solution both in vitro and in vivo. ORI nanosuspension with a particle size of 897.2 ± 14.2 nm was prepared by the high pressure homogenization method (HPH). MTT assay showed that ORI nanosuspension could significantly enhance the in vitro cytotoxicity against K562 cells compared to the ORI solution, the IC₅₀ value at 36 h was reduced from 12.85 μmol/L for ORI solution to 8.11 μmol/L for ORI nanosuspension. Flow cytometric analysis demonstrated that the ORI nanosuspension also induced a higher apoptotic rate in K562 cells compared to ORI solution. In vivo studies in a mouse model of sarcoma-180 solid tumors demonstrated significantly greater inhibition of tumor growth following treatment with ORI nanosuspension than ORI solution at the same dosage. The mice injected with ORI nanosuspension showed a higher reduction in tumor volume and tumor weight at the dose of 20 mg/kg compared to the ORI solution (P < 0.01), with the tumor inhibition rate increased from 42.49% for ORI solution to 60.23% for the ORI nanosuspension. Taken together, these results suggest that the delivery of ORI in nanosuspension is a promising approach for the treatment of the tumor.     

挤压综合征合并急性肾衰竭病人的护理研究

挤压综合征（crus syndrome，CS）合并急性肾衰竭（acute rehal failure，ARF）是一种外科严重创伤加内科急症的重危病症，病情严重复杂，并发症多，死亡率高，因而治疗和护理尤为重要。我科于2005年10月-2007年5月收治10例挤压综合征合并AFR病人经内、外科联合治疗和阶段化个体化整体护理，效果良好，现将护理介绍如下。     

Plasma volume during heat stress and exercise in women

Summary Five women were studied during exercise and passive heating to determine whether PV dynamics were affected by the menstrual cycle. The exercise bout (80% peak) on a modified cycle ergometer and the passive heat stress were done in a hot environment (T_a=50°C, P_w=1.61kPa) during the follicular and luteal phase. Esophageal temperature (T_es) was measured continuously. Blood samples were drawn after each 0.2° C increase in T_es and was measured at that time. Initial PV was estimated at rest during the follicular phase. PV changes from rest were calculated at each T_es from Hb and Hct. During passive heating, PV decreased by a mean volume of 156 (±80) ml to 2.83 (±0.09)l in the follicular phase. During the luteal phase, there was a larger volume reduction (300±100 ml) during passive heating, and the final PV was lower than in the follicular phase and averaged 2.47±0.181. During exercise, PV decreased 463 (±90) ml to 2.50 (±0.11) l in the follicular and 381 (±70) ml to 2.50 (±0.23) l in the luteal phase. These data indicate that there is a menstrual cycle effect on PV dynamics during passive heating such that more fluid is shifted out of the vasculature during the luteal phase. During severe exercise there is a greater fluid loss during the follicular phase, yet the final PV is not different between phases.     

Zinc homeostasis during lactation in a population with a low zinc intake.

BACKGROUND: There is a major increase in endogenous zinc excretion, specifically via the mammary gland, in early human lactation. Whereas fractional absorption of dietary zinc has been reported to increase in early human lactation, it is not known to what extent adaptive mechanisms may maintain zinc homeostasis, especially when dietary zinc intake is relatively low. OBJECTIVE: The objective of this study was to quantitate major variables of zinc homeostasis during early lactation in subjects from a population whose habitual dietary zinc intake is low. DESIGN: We studied 18 free-living lactating women from a rural community of northeast China whose infants were exclusively breast-fed. The subjects were studied at approximately 2 mo of lactation with use of stable isotopes of zinc and metabolic collection techniques. Milk volume was measured with use of a deuterium enrichment method. RESULTS: The mean (+/-SD) secretion of zinc in milk was 2.01 +/- 0.97 mg/d, the intake of zinc was 7.64 +/- 1.61 mg/d, and the fractional absorption of zinc was 0.53 +/- 0.09, for a total daily zinc absorption of 4.00 +/- 0.71 mg/d. Endogenous zinc excretion in urine and feces was 0.30 +/- 0.10 and 1.66 +/- 0.97 mg/d, respectively. CONCLUSIONS: Zinc balance, including zinc secreted in breast milk, was maintained at approximately 2 mo of lactation in women whose habitual diet was low in zinc. Homeostasis was achieved by high fractional absorption of zinc and intestinal conservation of endogenous fecal zinc.