高速逆流色谱在天然产物分离中的应用——紫杉烷类二萜及二萜生物碱的制备分离

高速逆流色谱是一种新发展起来的无载体的液液分配色谱技术。它利用聚四氟乙烯(PTFE)螺旋管的方向性与高速行星式运动相结合,产生一种独特的流体动力学现象,使互不相溶的两相溶液在螺旋管中充分混合,顺序传递,导致样品中各个组分由于分配系数的差别而有效的分离。本文介绍了国产的高速逆流色谱仪及应用该仪器制备分离云南红豆杉中结构相近的三种紫杉烷类二萜及二萜生物碱。     

Hospice Volunteer Programs: A Proposed Agenda

With the expansion of hospice services, volunteers are being increasingly used to provide emotional, spiritual, and tangible support to the terminally ill and their significant others. Unfortunately, little has been published about the experiences of hospice volunteers. In this paper, we (1) propose a timely agenda for the development and refinement of hospice volunteer programs; (2) outline basic program criteria about which there is emerging consensus; (3) delineate pertinent issues in the screening, training, and job performance of hospice volunteers; and (4) indicate how the implementation of formal program regulations and operations and program evaluation may benefit service recipients and institutional providers.     

Human spleen cell generation of factors stimulating human pluripotent stem cell, erythroid, and myeloid progenitor cell growth

Mitogen-stimulated murine spleen cells produce humoral substances capable of supporting murine hematopoiesis and pluripotent stem cell proliferation in vitro. Thus, we evaluated conditioned media generated by human spleen cells (SCM) in the presence or absence of mitogens for factors stimulatory for human pluripotent (CFU-GEMM), erythroid (BFU- E), and myeloid (CFU-GM) precursors. Two and one half percent to 10% SCM stimulated proliferation of all three types of precursor cells from nonadherent buoyant human marrow target cells. Mitogen-stimulated SCM augmented CFU-GM (175% to 225%), whereas CFU-GEMM and BFU-E growth was essentially unchanged. Cell separation procedures used to determine which cells provided these microenvironmental stimuli indicated that nonadherent mononuclear spleen cells provided the bulk of the CSF-GM, whereas adherent cells (95% nonspecific esterase + monocyte- macrophages) and nonadherent cells provided similar proportions of CSF- mix and erythroid burst-promoting activity (BPA). The nonadherent cells generating high levels of CSF-mix, BPA, and CSF-GM were predominantly Leu-1-negative, ie, non-T, cells. In the presence or absence of mitogens, SCM was a more potent source (1.3- to 3.8-fold) than peripheral leukocyte CM of the growth factors for the three progenitor cell types. Specific in situ cytochemical stains for analyzing morphology of myeloid colonies demonstrated that SCM stimulated the proliferation of the same types and proportions of colonies as human placental CM, suggesting that these CMs may contain similar CSF-GMs. These data show the contribution of spleen cell subsets to the generation of hematopoietic growth factors and the responsiveness of these cells to various mitogenic stimuli.     

Twenty-five years' experience with the arterial switch operation

OBJECTIVE: The arterial switch operation was introduced in 1976 to correct transposition of the great arteries and has since replaced atrial palliation. This study examines the long-term outcomes of the arterial switch operation. METHODS: Included in the study were 195 patients who underwent the arterial switch operation from 1977 through June 2000. Patients were evaluated for functional class, pulmonary stenosis, left ventricular function, arrhythmias, aortic sequelae, and coronary disease. RESULTS: Overall perioperative mortality was 15%, but rates dropped in the last 5 years to 4% for complex transposition and 0% for simple transposition. Of 151 survivors, 2 died late; 1 died of persisting pulmonary hypertension and 1 died of ventricular fibrillation after coronary pathologic changes. At last follow-up, a total of 145 patients were in New York Heart Association functional class I and 4 patients were in class II. The most frequent complication was pulmonary stenosis, necessitating 45 reinterventions in 26 patients. Left ventricular dysfunction was noted in 5 patients. Arrhythmias were seen in 5 patients: 2 patients had ventricular fibrillation (1 died and 1 required a defibrillator implantation), 1 had sick sinus syndrome, 1 had atrial flutter, and 1 had a single attack of supraventricular tachycardia. Aortic valve incompetence was absent or trivial in 146 patients, 3 had mild incompetence, 1 had moderate incompetence, and 1 had severe incompetence. Coronary sequelae were found in 5 of the 61 patients who underwent angiography. CONCLUSION: Long-term clinical outcome of the arterial switch operation is good, and perioperative mortality is now low. Morbidity is dominated by pulmonary stenosis and coronary artery disease, with the potential for lethal arrhythmias.     

Silver-nanoparticles increase bactericidal activity and radical oxygen responses against bacterial pathogens in human osteoclasts

Bone infections are difficult to treat and can lead to severe tissue destruction. Acute bone infections are usually caused by Staphylococcus aureus. Osteoclasts, which belong to the monocyte/macrophage lineage, are the key cells in bone infections. They are not well equipped for killing bacteria and may serve as a reservoir for bacterial pathogens. Silver has been known for centuries for its bactericidal activity. Here, we investigated the bactericidal effects of nano-silver particles in bacteria infected human osteoclasts. We found that nano-silver in per se non-toxic concentration enhanced the bactericidal activity in osteoclasts against intracellular Methicillin-resistant, virulent Staphylococcus aureus. The reduced bacterial survival in nano-silver pretreated cells correlated with increased reactive oxygen responses towards the invading pathogens. Overall, these results indicate that nano-silver compounds should be considered as an effective treatment and prevention option for bacterial bone and orthopedic implant infections.