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Using in utero transplantation into fetal sheep, we examined the capability of human bone marrow CD34+ cells fractionated based on Kit protein expression to provide long-term in vivo engraftment. Twelve hundred to 5,000 CD34+ Kit-, CD34+ Kit(low), and CD34+ Kit(high) cells were injected into a total of 14 preimmune fetal sheep recipients using the amniotic bubble technique. Six fetuses were killed in utero 1.5 months after bone marrow cell transplantation. Two fetuses receiving CD34+ Kit(low) cells showed signs of engraftment according to analysis of CD45+ cells in their bone marrow cells and karyotype studies of the colonies grown in methylcellulose culture. In contrast, two fetuses receiving CD34+ Kit(high) cells and two fetuses receiving CD34+ Kit- cells failed to show evidence of significant engraftment. Two fetuses were absorbed. A total of six fetuses receiving different cell populations were allowed to proceed to term, and the newborn sheep were serially examined for the presence of chimerism. Again, only the two sheep receiving CD34+ Kit(low) cells exhibited signs of engraftment upon serial examination. Earlier in studies of murine hematopoiesis, we have shown stage-specific changes in Kit expression by the progenitors. The studies of human cells reported here are in agreement with observations in mice, and indicate that human hematopoietic stem cells are enriched in the Kit(low) population. 相似文献
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Muriuki JK Ngeranwa JN Mwangi J Orinda G Lwembe R Khamadi S 《AIDS research and human retroviruses》2012,28(7):660-666
The isolation and characterization of primary strains of human immunodeficiency virus (HIV) is a vital tool for assessing properties of viruses replicating in HIV-infected subjects. HIV-1 isolation was carried out from 30 HIV-1-infected patients from a Comprehensive Care Clinic (CCC) after informed consent. Virus was successfully isolated from 9 out of the 30 samples investigated. Seven of the isolates were from drug-naive patients while two were from patients on antiretroviral drugs. The isolates were biologically phenotyped through measurement of the syncytium-inducing capacity in MT2 cells. Six of the isolates exhibited syncytia induction (SI) associated with CXCR4 coreceptor usage while three of the isolates were non-syncytia-inducing (NSI) isolates associated with CCR5 coreceptor usage. In addition, the replication capacity of the isolates was further determined in established cell line CD4(+) C8166. Indirect immunofluorescence assay was used to check the antigen expression on the cells as a supplementary test. HIV-1 isolation success was 70% (7/10) and 20% (2/20) in naive and drug-experienced patients, respectively. The majority of the viral isolates obtained (6/9) were of the SI phenotype, though SI virus strains are rare among non-B subtypes. A significant correlation between virus isolation success and viral load was established. Coreceptor use data for heavily treatment-experienced patients with limited treatment options are scanty and this is the group with perhaps the most urgent need of novel antiretroviral agents. 相似文献
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Introduction
An ideal ligature should tighten readily and remain tight. Ligature failure can be a critical complication of invasive procedures in human and veterinary surgical practice. Previous studies have tested various knots but not the constrictor knot.Methods
A new test bench was employed to compare six ligatures using four suture materials. As tension in a ligature is not readily measured, the study employed a surrogate measurement: the force required to slide a ligature along a rod. Benchmark values tested each suture material wrapped around the rod to establish the ratio between this force and the ligature tension for each material. Each ligature was tested first during tightening and then again afterwards. The benchmark ratios were employed to calculate the tensions to evaluate which ligature and which suture material retained tension best.Results
The model provided consistent linear relationships between the tension in the suture and the force required to pull the ligature along the rod. The constrictor knot retained tension in the ligature best (55–107% better than the next best ligature). Among the suture materials, polydioxanone had the greatest ability to retain the tension in a ligature and polyglactin the least.Conclusions
The constrictor knot showed superior characteristics for use as a ligature, and should be introduced into teaching and clinical practice for human and veterinary surgery. The new test bench is recommended for future testing of ligatures as well as objective comparison of suture materials. 相似文献19.
S Pengelly J Reader A Jones K Roper WJ Douie AW Lambert 《Annals of the Royal College of Surgeons of England》2014,96(3):216-218
Introduction
Stomas often have to be sited in emergencies by trainees who may have had little training in this. Emergency stomas and stomas where the site has not been marked preoperatively by a stoma therapist are more prone to complications. These complications may severely affect a patient’s quality of life. Advice in the literature on how to best site stomas is conflicting. We compared two easy anatomical methods of siting stomas to sites chosen by a stoma therapist and looked at how this site was affected by the patients’ body mass index (BMI).Methods
Patients undergoing elective colorectal surgery were seen either pre or postoperatively. Each patient’s BMI was recorded and the positions of three different potential stoma positions (site G: the gold standard, marked by a stoma therapist; site S: marked using a pair of scissors against the umbilicus; site H: halfway between the umbilicus and anterior superior iliac spine) were compared.Results
The two fixed anatomical methods described (method S and method H) both gave poor results. The most common reason for poor siting was the proximity of a skin crease. There was a statistically significant correlation between the patient’s BMI and the laterality of the gold standard site.Conclusions
The two simple anatomical methods described here do not provide a shortcut to effective siting. A more effective method may be calculating the laterality of the site using the patient’s BMI, and then moving up/down to avoid a skin crease and improve the patient’s view for changing the bag. This deserves further study. 相似文献20.
S Dixon AW Blom MR Whitehouse V Wylde 《Annals of the Royal College of Surgeons of England》2014,96(1):61-66