Skin-derived human adult stem cells surprisingly share many features with human pancreatic stem cells

Multiple tissue niches in the human body are now recognised to harbour stem cells. Here, we have asked how different adult stem cell populations, isolated from two ontogenetically distinct human organs (skin, pancreas), actually are with respect to a panel of standard markers/characteristics. Here we show that an easily accessible adult human tissue such as skin may serve as a convenient source of adult stem cell-like populations that share markers with stem cells derived from an internal, exocrine organ. Surprisingly, both, human pancreas- and skin-derived stem/progenitor cells demonstrate differentiation patterns across lineage boundaries into cell types of ectoderm (e.g. PGP 9.5+ and GFAP+), mesoderm (e.g. alpha-SMA+) and entoderm (e.g. amylase+ and albumin+). This intriguing differentiation capability warrants systemic follow-up, since it raises the theoretical possibility that an adult human skin-derived progenitor cell population could be envisioned for possible application in cell replacement therapies.     

Comparison of craniofacial features of major human groups

Distance analysis and factor analysis, based on Q-mode correlation coefficients, were applied to 23 craniofacial measurements in 1,802 recent and prehistoric crania from major geographical areas of the Old World. The major findings are as follows: 1) Australians show closer similarities to African populations than to Melanesians. 2) Recent Europeans align with East Asians, and early West Asians resemble Africans. 3) The Asian population complex with regional difference between northern and southern members is manifest. 4) Clinal variations of craniofacial features can be detected in the Afro-European region on the one hand, and Australasian and East Asian region on the other hand. 5) The craniofacial variations of major geographical groups are not necessarily consistent with their geographical distribution pattern. This may be a sign that the evolutionary divergence in craniofacial shape among recent populations of different geographical areas is of a highly limited degree. Taking all of these into account, a single origin for anatomically modern humans is the most parsimonious interpretation of the craniofacial variations presented in this study. © 1996 Wiley-Liss, Inc.     

Toxicity and mutual interactions of cadmium and zinc ions in normal and carcinogen-transformed mouse cells

The toxicity of chloride salts of physiological (zinc, manganese, nickel) and non physiological (cadmium) bivalent metal ions was studied in normal or carcinogen-transformed mouse embryo fibroblast cells. The dose response curves for toxicity to both types of cells exhibited similar shapes. The transformed cells, however, were about twice as sensitive to zinc toxicity as normal cells. When normal and transformed cells were grown together and incubated for several hours with an appropriate concentration of zinc, the malignant cells were selectively killed. Cadmium was much more toxic than the three other metal ions in both types of cells. Its toxic effect was reversed by simultaneous addition of zinc at nontoxic concentrations.Abbrevications CFA colony forming ability - MCA 3-methylcholanthrene     

Stenotrophomonas maltophilia interaction with human epithelial respiratory cells in vitro

Bacteria of Stenotrophomonas maltophilia have been isolated with increasing frequency from the airways of cystic fibrosis (CF) patients, usually following P. aeruginosa infections, but their adherence to human epithelial respiratory cells has never been investigated. In this study, various S. maltophilia strains were seen to adhere to epithelial respiratory cells in vitro, mainly along intercellular junctions. Bacteria could also enter into host cells, as determined by the gentamicin exclusion assay and transmission electron microscopy. Cells co-incubated with P. aeruginosa and S. maltophilia exhibited a significantly decreased adherence of these latter bacteria. No decrease in S. maltophilia adherence was observed when co-infection was carried out with heat-killed P. aeruginosa or when respiratory cells were first incubated with P. aeruginosa, before incubation with S. maltophilia. Our data suggest that P. aeruginosa infections do not account for the increased prevalence of S. maltophilia in CF patient airways, that thermolabile products from P. aeruginosa can control the adherence of S. maltophilia to respiratory cells and also that these two bacteria do not compete for cell receptors.     

Effects of prostacyclin on ultrastructural features of human platelets in vitro

Examining platelets plasma-membrane by freeze-etching (FE)-technique irregularly placed among the “particles”, some larger formations, called by us “protuberances” can be seen. These protuberances may represent the stomata of the open canalicular system (OCS) and the morphological aspect of an exocytotic process. Addition of prostacyclin to platelet rich plasma (PRP) leads to a decrease of the average value of protuberances which is statistically significant in comparison to control platelets.     

Bacopasaponins with cytotoxic activity against human breast cancer cells in vitro

Molecular Biology Reports - Globally, breast cancer is a serious concern that exhibits a persistent rise in its incidence and related mortality even after significant advancement in the field of...     

Rapid chemosensitivity assay with human normal and tumor cells in vitro

Summary Neutral red assay, as an index of cytotoxicity, has been applied to predictive screening of chemotherapeutic agents. Human hepatoma and melanoma tumor cells and normal melanocytes, keratinocytes and fibroblasts were incubated for 2, 24, and 48 h with graded concentrations of cis-platinum (0.1 to 80 μM), doxorubicin (0.01 to 100 μM), and 5-fluorouracil (1 to 1000 μM). Cells were most sensitive after 48 h. Tumor cells, based on 50% toxicity values, were 2–4 times more sensitive than the normal cells, except for cis-platinum, where only melanoma cells, as compared to normal melanocytes, showed a marked difference in cytotoxic response. Methotrexate (1 to 10 μM) toxicity could be reversed in the presence of 100 μM of leucovorin. This sensitive, rapid, and economical assay is suitable for preclinical screening and drug development. This work has been supported, in part, by funds from Schering Corporation, New Jersey, and Chevron Environmental Health Center, Inc., California.     

Rescue of senescent human fibroblasts by hybridization with hamster cells in vitro

Cell hybridization studies were carried out to explore the nature of senescence of diploid human fibroblasts in vitro. A heteroploid line of golden hamster cells was fused with four different strains of senescent human fibroblasts with production of viable hybrids in each case. This suggests that senescence in vitro is a quasidifferentiated state which is amenable to genetic reprogramming.     

Electrochemical treatment of human KB cells in vitro

Electrochemical treatment (ECT) of cancer is a promising new method by which direct current is delivered into tumor tissue to induce tumor regression. The purpose of this study is to evaluate the effectiveness of ECT on human cancer cells and to investigate the factors that affect ECT. The biological mechanisms of ECT in cancer treatment were also explored. Using human KB cells, ECT was found to delay cell growth by using 0.3 coulombs (C)/ml (1.5 C in 5 ml of culture medium; 3 V, 400 μA for 62.5 min). From the results of a colony‐forming assay, it was clearly demonstrated that increasing the ECT dose decreases tumor cell survival. A cytotoxicity study, in which a methylene blue assay was used, determined that, for 2.5 × 10⁵ cells in culture, the ID₅₀ was 0.68 C/ml. For a fixed dose of 0.6 C/ml (3 C in 5 ml), using higher current and shorter treatment time resulted in better cell survival. Time, therefore, is an important factor. When cell concentration was altered, the survival was higher for increased cell concentrations. A thymidine incorporation assay indicated that the amount of [³H]thymidine incorporated into DNA decreased as the ECT dose increased. After treatment with 1 C/ml (5 C in 5 ml; 3 V, 400 μA for 208.4 min), pH at the anode decreased to 4.53 and at the cathode increased to 10.46. These results indicate that ECT is effective for killing human KB cells in vitro and that the toxicity effect is related to charge, current, and treatment time. The effect of pH alteration on cells is one of the mechanisms of ECT. Bioelectromagnetics 20:34–41, 1999.© 1999 Wiley‐Liss, Inc.     

Serial propagation of human endothelial cells in vitro

Human umbilical vein (HUV) endothelial cells were grown for 15 to 21 passages at a split ratio of 1:5 (at least 27 population doublings) on a human fibronectin (HFN) matrix in Medium 199 supplemented with fetal bovine serum (FBS) and endothelial-cell growth factor (ECGF). This system also permitted the growth of HUV endothelial cells at cell densities as low as 1.25 cells/cm2. In addition to delaying the premature senescence of HUV endothelial cells, ECGF also reduced the serum requirement for low-density HUV endothelial-cell growth; 2.5% serum and ECGF yields half-maximum growth as compared to high serum controls. Significant HUV endothelial-cell growth was also observed in medium supplemented with either ovine hypophysectomized (HYPOX) serum, plasma-derived serum (PDS), or HYPOX-PDS in the presence of ECGF, suggesting that neither the pituitary nor the platelet contributes to HUV endothelial-cell growth.     

Surface morphology of trypsinized human cells in vitro

Chang human liver cells were observed by phase contrast and scanning electron microscopy during trypsin treatment of monolayer cultures. The flattened interphase cell was caused to round up into a spherical structure leaving behind long slender cytoplasmic processes, named trypsinization retraction fibrils, which resemble the mitotic retraction fibrils but differ from these by being formed more rapidly (1–2 min). Another type of long microextensions revealed by the enzymatic treatment are the attachment fibrils, which are intercellular cytoplasmic strings under tension. The short microextensions projecting from the surface of the normal interphase cells disappear during the first 5 min of exposure to 0.03% trypsin solution.     

用体外免疫的人淋巴细胞建立抗破伤风类毒素的...

Human tonsil cells in vitro immunized with tetanus toxoid were fused with human-mouse heteromyeloma line RF to generate human-mouse hybridomas. Hybridoma 891112-50 was cloned and 2 subclones (891112-50-3 and -4) were obtained. The secreted antibodies from the subclones were antigen specific, since they did not cross react with three irrelevant antigens (OVA, TCS and F gamma G). The hybridomas were quite stable. After 13 passages in tissue culture flasks, they still retained their antibody secreting ability. From flow cytometry analysis the subclone 50-3 was more stable than the subclone 50-4. The human immunoglobulin contained in supernatant collected during regular passages was equivalent to 69.6 micrograms/ml.