A statistical analysis of murine stem cell suicide techniques

The clinical application of soft agar cloning techniques for granulocyte-macrophage stem cells (CFU-C) has resulted in a number of contradictory reports that may in part be due to an inadequate data base. Growth of murine CFU-C is more reproducible and less variable than that of human CFU-C. We utilized in vivo hydroxyurea suicide of murine marrow CFU-C to address the question of how many experiments are needed to detect a specific difference with a p of less than 0.05. In 66 experiments the mean marrow CFU-C hydroxyurea kill was 23.3%; 6-9 separate experiments were necessary to detaect differences of 25%-30%. In order to be sure that a 25%-30% difference is not present, 15-21 experiments were required. Using a Dec-20 computer, 1000 samples of sample size 3, 4, or 10 were drawn from the 66 experiments; it was found that with 3 experiments and a true value of 23%, the actually observed value was below 10%, 17% of the time, and was over 40% in 10% of the samplings. In a smaller number of experiments similar results were obtained analyzing 3HTdR suicide of pluripotent stem cells and CFU- C. These data could provide a base from which to judge the validity of studies utilizing the CFU-C technique.     

小唾液腺癌治疗新进展

该文旨在对小唾液腺癌的治疗进行回顾。小唾液腺癌可发生在头颈部很多位置,通常表现为黏膜下肿块。影像学检查是对肿瘤发病部位及病变范围内解剖结构的关系进行评估的基础。切取活检或穿吸活检可以决定肿瘤的病理类型和分级。随着分子生物学技术的不断进步,小唾液腺癌的诊断     

Higher order aberrations,refractive error development and myopia control: a review

Evidence from animal and human studies suggests that ocular growth is influenced by visual experience. Reduced retinal image quality and imposed optical defocus result in predictable changes in axial eye growth. Higher order aberrations are optical imperfections of the eye that alter retinal image quality despite optimal correction of spherical defocus and astigmatism. Since higher order aberrations reduce retinal image quality and produce variations in optical vergence across the entrance pupil of the eye, they may provide optical signals that contribute to the regulation and modulation of eye growth and refractive error development. The magnitude and type of higher order aberrations vary with age, refractive error, and during near work and accommodation. Furthermore, distinctive changes in higher order aberrations occur with various myopia control treatments, including atropine, near addition spectacle lenses, orthokeratology and soft multifocal and dual-focus contact lenses. Several plausible mechanisms have been proposed by which higher order aberrations may influence axial eye growth, the development of refractive error, and the treatment effect of myopia control interventions. Future studies of higher order aberrations, particularly during childhood, accommodation, and treatment with myopia control interventions are required to further our understanding of their potential role in refractive error development and eye growth.     

Plasma levels of plasminogen activator inhibitor type 1, beta- thromboglobulin, and fibrinopeptide A before, during, and after treatment of acute myocardial infarction with alteplase

Plasma levels of plasminogen activator inhibitor type-1 (PAI-1), beta- thromboglobulin (beta TG), and fibrinopeptide A (FPA) were followed over 24 hours in 30 patients treated with alteplase for acute myocardial infarction. Samples were taken at baseline (T Oh), after 90 minutes (under alteplase, no heparin, T 1.5h), after 120 minutes (under alteplase and heparin, T 2h), 30 minutes after thrombolytic therapy (T 3.5h), as well as 12 hours (T 12h) and 24 hours (T 24h) after baseline. PAI-1 antigen levels (55 +/- 9 ng/mL at T Oh, mean +/- SEM) decreased to 35 +/- 5 (T 1.5h) and 40 +/- 6 (T 2h) ng/mL under alteplase, before increasing to 84 +/- 22 (T 3.5h), 130 +/- 30 (T 12h), and 64 +/- 7 (T 24h) ng/mL after therapy, P less than .001. A high baseline PAI-1 activity (18 +/- 3 ng/mL) decreased to 2.0 +/- 0.4 (T 1.5h) and 1.7 +/- 0.2 (T 2h) under alteplase and increased to 32 +/- 5 (T 12h) and 19 +/- 3 (T 24h) ng/mL after therapy (P less than .0001). beta TG levels (339 +/- 105 ng/mL at T Oh) decreased to 203 +/- 48 (T 2h), 154 +/- 51 (T 3.5h), 187 +/- 40 (T 12h), and 142 +/- 32 (T 24h) ng/mL under heparin (P less than .01). FPA levels (34 +/- 9 ng/mL at T Oh) increased to 85 +/- 15 ng/mL under alteplase alone (T 1.5h) and normalized under heparin (11 +/- 4, 6 +/- 2, 4 +/- 2, and 3 +/- 1 ng/mL at T 2h, T 3.5h, T 12h, and T 24h, respectively). A high level of FPA at T 3.5h correlated with reocclusion (33 +/- 12 ng/mL, n = 4 v 2.9 +/- 0.5 ng/mL, n = 21, P less than .005). We conclude that plasma levels of PAI- 1 antigen as well as activity markedly increase after alteplase therapy of acute myocardial infarction. The high activity of PAI-1 and decreasing beta TG levels suggest that platelets do not contribute significantly to this phenomenon. The marked increase of FPA levels under recombinant tissue-type plasminogen activator alone and its normalization under heparin emphasize the important role of concomitant anticoagulation in controlling further intravasal fibrin generation under alteplase.     

The growth factor requirements of STRO-1-positive human bone marrow stromal precursors under serum-deprived conditions in vitro

Factors that regulate the growth and development of primitive bone marrow stromal cell precursors are not well defined. We have examined 25 purified recombinant growth factors for their ability to initiate and support clonogenic growth of fibroblast colony-forming cells (CFU- F) from adult human bone marrow. Assays were performed using bone marrow mononuclear cells (BMMNC) enriched in CFU-F by magnetic- activated cell sorting (MACS) using the monoclonal antibody (MoAb) STRO- 1. A serum-deprived assay was developed to avoid components of fetal calf serum (FCS) that may mask or otherwise modify the response of CFU- F to exogenously added factors. L-ascorbate and the glucocorticoid dexamethasone were found to be essential for CFU-F colony development under serum-deprived conditions. Importantly, clonogenic growth of CFU- F in this culture system was absolutely dependent on an exogenous source of growth factor. Platelet-derived growth factor-BB (PDGF) and epidermal growth factor (EGF) demonstrated the greatest ability to support colony growth. Colony formation was dose-dependent, with half- maximal colony numbers at approximately 0.2 ng/mL for either factor and plateau numbers at concentrations in excess of 1.0 ng/mL. Simultaneous addition of PDGF and EGF had no effect on the number of colonies initiated but resulted in dose-dependent increases in mean colony diameter that were significant (P < or = .05) when compared with the effect of either factor alone or with the size of colonies elicited in control cultures by 20% FCS. Fluorescence-activated cell sorting (FACS) of BMMNC using MoAbs to the alpha chain of the PDGF receptor and to the EGF receptor in combination with the Moab STRO-1 demonstrated constitutive expression of both receptors by greater than 90% on CFU-F. Receptors for insulin-like growth factor-1 (IGF-1) and nerve growth factor (NGF) were also detected on STRO-1+ CFU-F, but in vitro both IGF- 1 and NGF did not support colony growth. This report demonstrates the development of a simple, reproducible, and stringent culture system for the growth and assay of stromal precursors under serum-deprived conditions and represents an important prerequisite for future studies of the role of growth factors in the regulation of stromal cell proliferation, differentiation, and development.     

Proliferation of myeloid progenitor cells in human long-term bone marrow cultures is stimulated by interleukin-1 beta

To study the effect of interleukin-1 (IL-1) beta on the proliferation of hematopoietic progenitor cells (HPC) in long-term bone marrow cultures (LTBMC), stromal cell layers were established from normal human bone marrow. Autologous cryopreserved mononuclear phagocyte- and T-lymphocyte-depleted bone marrow cells were reinoculated on the stromal layers in fresh culture medium, with or without the addition of human IL-1 beta (30 U/mL). Once a week, half of the culture supernatant was replaced with fresh culture medium with or without IL-1, and all nonadherent cells were returned to the flasks. At weekly intervals during a period of 5 weeks, one culture was sacrificed to determine the total number of cells and hematopoietic progenitor cells, present in the adherent and the nonadherent cell fractions. In IL-1-stimulated cultures, the number of cells recovered during a period of 5 weeks exceeded the number of cells in unstimulated control cultures by 1.5 times. This difference was attributed to a twofold increase in the number of adherent cells. The number of HPC recovered from IL-1- stimulated cultures was not different from that recovered from controls. The levels of colony-stimulating activity (CSA) in supernatants from IL-1-stimulated cultures were significantly higher than those in supernatants from control cultures. These results indicate that IL-1 enhances the recovery of cells in LTBMC by stimulating the proliferation of HPC with the concurrent release of CSA from stromal cells, without diminishing the number of HPC.