In vitro morphological characterization of the bursal reticuloepithelial (REp) cells of chicken.

The REp cells of the bursa follicle medulla of chicken were isolated in vitro. Culture of the REp cells was maintained over a period of 10 days and the cells were observed at 3 and 10 days by means of transmission electron microscopy (TEM) and immunofluorescence. The use of an anticytokeratin monoclonal antibody confirmed their epithelial nature. TEM observations showed the presence of desmosomes and tonofilaments, which are characteristic of epithelial cells. Furthermore, to some extent the cells regenerated in vitro the network they form in vivo. Though the growth rate becomes slower with time, the features of the REp cells do not significantly change.     

Apoptotic cell death in the lactating mammary gland is enhanced by a folding variant of α-lactalbumin

Apoptosis is essential to eliminate secretory epithelial cells during the involution of the mammary gland. The environmental regulation of this process is however, poorly understood. This study tested the effect of HAMLET (human -lactalbumin made lethal to tumor cells) on mammary cells. Plastic pellets containing HAMLET were implanted into the fourth inguinal mammary gland of lactating mice for 3 days. Exposure of mammary tissue to HAMLET resulted in morphological changes typical for apoptosis and in a stimulation of caspase-3 activity in alveolar epithelial cells near the HAMLET pellets but not more distant to the pellet or in contralateral glands. The effect was specific for HAMLET and no effects were observed when mammary glands were exposed to native a-lactalbumin or fatty acid alone. HAMLET also induced cell death in vitro in a mouse mammary epithelial cell line. The results suggest that HAMLET can mediate apoptotic cell death in mammary gland tissue.Received 30 January 2004; received after revision 5 March 2004; accepted 16 March 2004     

Neurogenic effects of β-amyloid in the choroid plexus epithelial cells in Alzheimer’s disease

β-amyloid (Aβ) can promote neurogenesis, both in vitro and in vivo, by inducing neural progenitor cells to differentiate into neurons. The choroid plexus in Alzheimer’s disease (AD) is burdened with amyloid deposits and hosts neuronal progenitor cells. However, neurogenesis in this brain tissue is not firmly established. To investigate this issue further, we examined the effect of Aβ on the neuronal differentiation of choroid plexus epithelial cells in several experimental models of AD. Here we show that Aβ regulates neurogenesis in vitro in cultured choroid plexus epithelial cells as well as in vivo in the choroid plexus of APP/Ps1 mice. Treatment with oligomeric Aβ increased proliferation and differentiation of neuronal progenitor cells in cultured choroid plexus epithelial cells, but decreased survival of newly born neurons. These Aβ-induced neurogenic effects were also observed in choroid plexus of APP/PS1 mice, and detected also in autopsy tissue from AD patients. Analysis of signaling pathways revealed that pre-treating the choroid plexus epithelial cells with specific inhibitors of TyrK or MAPK diminished Aβ-induced neuronal proliferation. Taken together, our results support a role of Aβ in proliferation and differentiation in the choroid plexus epithelial cells in Alzheimer’s disease.     

Synthesis of sulfated glycosaminoglycans by the three cell types of the rabbit cornea in culture.

Rabbit corneal cells were cultivated for 21 days and then exposed to Na235SO4, a precursor of sulfated glycosaminoglycans (GAG). All 3 cell types of the cornea, the fibroblasts, the epithelial as well as the endothelial cells, synthesize GAG. The fractionation-patterns of the epithelial and endotherlial GAG are almost identical and differ clearly from the one of fibroblastic GAG.     

Primary culture of dispersed skin epidermal cells of rainbow trout Oncorhynchus mykiss Walbaum

This is the first report on a primary culture of dispersed skin epidermal cells of rainbow trout Oncorhynchus mykiss Walbaum. These primary cells revealed a low seeding efficiency after 3 days (11.6 ± 4.6%), whereas subcultured cells had a higher seeding efficiency at the same time point (75.5 ± 34.0%) and increased in cell number (150 – 200% of seeded cells after 20 to 30 days). The cells were characterized applying histological, immunocytochemical and ultrastructural methods. The culture consisted of undifferentiated keratinocytes. Mucous cells as well as differentiated epithelial cells were absent. To date the cells were cultured for maximally 9 passages and 402 days and therefore provide the possibility for long-term studies. Received 31 March 1998; received after revision 14 July 1998; accepted 14 July 1998     

Clara cell surface of the rat: scanning and transmission electron microscopic study

Summary In normal young rats, groups of Clara cells in the bronchioles showed the formation of many cytoplasmic blebs on their cytoplasmic domes. Detached blebs rested on the bronchiolar epithelial cells. The scanning (SEM) and transmision electron microscope (TEM) studies suggest localized changes of Clare cell surface activities by increased formation of cytoplasmic blebs which may represent the apocrine type of secretion.This project was supported by research grants from NIH HD-10139 and the American Heart Association, Kansas Affiliate. We used the Electron Microscope Research Service Laboratory of the University of Kansas Medical Center.     

肝癌细胞系Hep3B中CD133+细胞亚群的分离及其特性的研究

目的研究CD133在人肝癌细胞系Hep3B中的表达以及CD133+细胞的体外增殖、自我更新及体内成瘤能力,初步探讨肝癌中CD133+细胞亚群的干细胞特性。方法流式细胞仪检测未分选的Hep3B细胞中CD133+细胞表达情况;免疫磁珠分选技术纯化CD133+肿瘤细胞;MTT法检测CD133+细胞体外增殖能力;无血清培养纯化...     

Synthesis of sulfated glycosaminoglycans by the three cell types of the rabbit cornea in culture

Summary Rabbit corneal cells were cultivated for 21 days and then exposed to Na₂ ³⁵SO₄, a precursor of sulfated glycosaminoglycans (GAG). All 3 cell types of the cornea, the fibroblasts, the epithelial as well as the endothelial cells, synthesize GAG. The fractionation-patterns of the epithelial and endothelial GAG are almost identical and differ clearly from the one of fibrolastic GAG.Supported by SNSF, grant No. 3.534.71.     

Production of insulin-like growth factor I (IGF-I) and IGF-binding proteins by rat intestinal stromal cells in vitro

To determine if intestinal stromal cells secrete diffusible factors such as insulin-like growth factors (IGFs) capable of regulating epithelial cell growth in vitro, stromal cells were isolated by enzymatic digestion of rat intestine. Incorporation of [³H]thymidine into DNA and [¹⁴C]leucine into protein of IEC-6 cells, a model intestinal epithelial cell line, was significantly increased (two- to threefold) when the IEC-6 cells were co-cultured with stromal cells, relative to IEC-6 cells grown alone. Medium conditioned by stromal cells stimulated DNA synthesis of IEC-6 cells in a dose-dependent manner. Analysis of the conditioned medium revealed that intestinal stromal cells secreted IGF-I, but little IGF-II, in addition to an M _r 32,000 IGF-binding protein (IGFBP-2) and an IGFBP having M _r∼ 24,000. We conclude that rat intestinal stromal cells secrete one or more diffusible factors, which may include IGF-I and IGFBPs, capable of stimulating proliferation of IEC-6 cells in vitro. Received 25 August 1997; received after revision 7 November 1997; accepted 20 November 1997     

Effect of periodate oxidation of glycoconjugates of lymphocyte membranes on the immune response in vitro]

Mouse spleen cells treated with sodium periodate for 10 min. at 4 degrees C are stimulated to undergo blastogenesis and to incorporate thymidine. The effect of such treatment on the antibody response in vitro induced by Sheep red blood cells has been evaluated. Periodate-induced proliferation is accompanied by a marked inhibition of the immune response to this antigen. At concentrations leading to mitogenesis, no cytotoxic effect of periodate was observed and treated cells survived well on tissue culture. Cell recoveries from samples treated with periodate at the optimal mitogenic dose, were markedly enhanced when harvested at different days after culturing wheras lower antibody forming cells numbers wereconsistently observed during the culture period.     

Influence of beta-aminoproprionitrile (BAPN) on cell growth and elastic fiber formation in cultures of auricular chondrocytes

Auricular chondrocytes isolated from 4-day-old rabbits and grown in vitro for 14 days, proliferated rapidly and produced a conspicuous network of elastic fibers. Beta-aminoproprionitrile (BAPN), which in vivo inhibits cross-linking of elastin, decreased the formation of elastic fibers at a concentration of 10-20 micrograms/ml and prevented formation at 40 micrograms/ml. At a concentration of 5 micrograms/ml only the so-called patches of elastin appeared to be absent. The inhibitory effect of BAPN on cell growth did not exceed 10%, which indicates that BAPN is only slightly harmful to auricular chondrocytes and can safely be used in studies on elastin deposition by these cells in vitro.     

Comparative study of the effect of thymosin and supernatant from epithelial thymic cells on antibody production (author's transl)]

A thymic extract (TE) was prepared from supernatant of mice thymic epithelial cultures according to the purification of thymosin. TE and thymosin stimulated, in vitro, the immune response of mouse against deep red blood cells.     

17 Beta-estradiol-sensitivity of cultured myometrial cells

The estrogen sensitivity of cells cultured from the rat myometrium was studied by growing the cells in the absence or presence of 1 nM 17 beta-estradiol. Following a time lag of approximately 10 days, exposure to estrogen resulted in increased incorporation of radiothymidine by the cells. Estrogen treatment also decreased isoproterenol-dependent and GTP-dependent adenylate cyclase activity, but had no effect on basal activity. These cultured cells have been shown previously to have some properties of uterine smooth muscle. The effects estrogen has in vitro, therefore, may reflect important properties in vivo that account for the mechanism by which the sex steroid decreases the sensitivity of the myometrium to isoproterenol.     

Effect of the type of diet on the distribution of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in rat small intestine

Summary The jejunoileal gradient for the HMG-CoA reductase activity in the microsomal fraction of the epithelial cells of the small intestine of rats given commercial pellets was reserved within a few days after changing the ration to a semipurified diet. The response of the reductase was essentially the same in villus and crypt cells.     

In vivo and in vitro study of the effect of pregnant female serum graft rejection in Salamandra salamandra Lin]

Serum from pregnant female Salamandra salamandra inhibits the cytotoxic reaction from the mother towards its larvae. Such a serum accelerates the allograft rejection reaction. In vitro studies show that a serum from pregnant female inhibits the cytotoxic reaction of host spleen cells towards epithelial cells of the donor of the graft.     

Circadian rhythm of apical Na-channels and Na-transport in rabbit distal colon

Summary In vivo and in vitro studies showed that electrogenic sodium transport in rabbit distal colon is modulated by aldosterone. It varies in a circadian rhythm; the external synchronizer is the light-dark cycle. The site of regulation was found to be in the apical membrane of colonic epithelial cells, in which the number of conducting sodium-channels is increased by aldosterone.     

Circadian rhythm of apical Na-channels and Na-transport in rabbit distal colon

In vivo and in vitro studies showed that electrogenic sodium transport in rabbit distal colon is modulated by aldosterone. It varies in a circadian rhythm; the external synchronizer is the light-dark cycle. The site of regulation was found to be in the apical membrane of colonic epithelial cells, in which the number of conducting sodium-channels is increased by aldosterone.     

Promotion of epithelial keratinization by N-methyl-N'-nitro-N-nitrosoguanidine in rat forestomach in organ culture.

The effect of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on epithelial differentiation of fetal rat forestomach was investigated in organ culture. When forestomach tissues removed from 16.5-day fetuses were treated with 5 microgram and 3 microgram of MNNG per ml for 1 h, epithelial keratinization was observed after 4 and 5 days, respectively, whereas it occurred after 6 days in control cultures. A clear dose-response relationship was found in the promotion of epithelial keratinization by MNNG.     

Oxygen consumption of the rat small intestine during infection with nematospiroides dubius

Summary Qo₂ of jejunal rings did not differ significantly between uninfected rats and rats infected for 7 days withNematospiroides dubius. Qo₂ of isolated jejunal mucosal epithelial cells was significantly greater 7 days after infection than in uninfected controls or at 29–36 days after infection.     

Parvalbumin alters mitochondrial dynamics and affects cell morphology

The Ca²⁺-binding protein parvalbumin (PV) and mitochondria play important roles in Ca²⁺ signaling, buffering and sequestration. Antagonistic regulation of PV and mitochondrial volume is observed in in vitro and in vivo model systems. Changes in mitochondrial morphology, mitochondrial volume and dynamics (fusion, fission, mitophagy) resulting from modulation of PV were investigated in MDCK epithelial cells with stable overexpression/downregulation of PV. Increased PV levels resulted in smaller, roundish cells and shorter mitochondria, the latter phenomenon related to reduced fusion rates and decreased expression of genes involved in mitochondrial fusion. PV-overexpressing cells displayed increased mitophagy, a likely cause for the decreased mitochondrial volumes and the smaller overall cell size. Cells showed lower mobility in vitro, paralleled by reduced protrusions. Constitutive PV down-regulation in PV-overexpressing cells reverted mitochondrial morphology and fractional volume to the state present in control MDCK cells, resulting from increased mitochondrial movement and augmented fusion rates. PV-modulated, bi-directional and reversible mitochondrial dynamics are key to regulation of mitochondrial volume.