Search results for "VITRO"

Insulin synthesis in chick embryo retinas during development.

1994

Retinas of chick embryos contain insulin (1) and further, are capable of synthesizing it, as demonstrated by incubating retinas at different ages (7th–18th day) with [3H]leucine. The synthesized radioactive insulin was isolated and assayed by means of a HPLC procedure. The synthesis of insulin was found to be highest in the youngest retinas studied (day 7), afterwards it declined with age except for an increment found at 14–15 day. Explants of chick embryo retinas, cultured in vitro, rapidly degraded insulin. Nevertheless, the content of immunoreactive insulin in retinal explants diminished slowly with the age of culture, so that, after 8 days of incubation, it was about 60% of the content …

The effect of tacrine on acetylcholine overflow in the heart

1990

Tacrine, 10(-6) M, enhanced the acetylcholine (ACh) overflow evoked in perfused chicken hearts by field stimulation (5 Hz, 1 min) from 183 to 346 pmol g-1 min-1. Increase to the same level were observed after pretreatment with diisopropylfluorophosphate (DFP) as well as after DFP plus 10(-6) M tacrine. Tacrine, 10(-5) M, caused further enhancement with or without DFP up to 851 pmol g-1 min-1. It was concluded that 10(-6) M tacrine enhanced the ACh overflow by choline esterase inhibition, whereas 10(-5) M tacrine caused, in addition, an increase of neuronal ACh release.

NAD- and NADP-linked dehydrogenases in the sciatic nerve of rats injected with di-isopropylfluorophosphate.

1966

Sinusoidal endothelial liver cells in vitro release endothelin — Augmentation by transforming growth factorβ and Kupffer cell-conditioned media

1991

Endothelin is the most potent vasoconstrictor peptide known today. Using a radioimmunoassay for endothelin, we measured immunoreactive endothelin in culture media of guinea pig sinusoidal endothelial liver cells and human umbilical vein endothelial cells. A time-dependent release of immunoreactive endothelin by confluent sinusoidal endothelial liver cells in culture was found. Sinusoidal endothelial liver cells produced similar amounts of immunoreactive endothelin as umbilical vein endothelial cells, about 900 pg/microgram DNA per 24 h. In the presence of transforming growth factor beta a dose-dependent increase of immunoreactive endothelin release was measured. The maximal increase of 50% …

Cigarette smoke extract activates human bronchial epithelial cells affecting non-neuronal cholinergic system signalling in vitro.

2010

Abstract Aims Acetylcholine (ACh) is synthesized by Choline Acetyl-Transferase (ChAT) that exerts its physiological effects in airway epithelial cells via muscarinic receptor (MR) activation. We evaluate the effect of ACh stimulation on human bronchial epithelial cells (16-HBE) and test whether cigarette smoke extract (CSE) can modify the basal cellular response to ACh affecting the non-neuronal cholinergic system signalling. Main methods ACh stimulated 16-HBE were tested for ACh-binding, Leukotriene B 4 (LTB 4 ) release and ERK1/2 and NFkB pathway activation. Additionally, we investigated all the aforementioned parameters as well as ChAT and MR proteins and mRNA expression and endogenous A…

Islet beta-cell apoptosis triggered in vivo by interleukin-1beta is not related to the inducible nitric oxide synthase pathway: evidence for mitochon…

2003

IL-1beta is recognized as an effector cytokine contributing to islet beta-cell destruction during diabetes. We have previously shown in vitro that IL-1beta induces nitric oxide (NO) and beta-cell damage. Here, we show that IL-1beta administration in vivo to Wistar rats transiently increases manganese superoxide dismutase activity, whereas inducible NO synthase is not detected, and the levels of nitrate+nitrate do not change. Moreover, a significant decrease of mitochondrial aconitase, leading to a rise of hydroperoxides, and islet beta-cell apoptosis, involving caspase-3 and -8, is observed. Analysis of adhesion molecules in beta-cells showed that intercellular adhesion molecule-1 is highly…

Guinea pig Kupffer cells can be activated in vitro to an enhanced superoxide response

1988

Summary In the preceding paper it was shown that Kupffer cells isolated by digestion of the liver and purified by centrifugal elutriation can be activated in vitro by lipopolysaccharide and muramyl dipeptide to an enhanced superoxide response upon zymosan phagocytosis. Lipopolysaccharide and muramyl dipeptide also led to a strongly increased prostaglandin E 2 release during the phagocytosis of zymosan. This activation was accompanied by an increased production of prostaglandin E 2 during the incubation with the stimuli. Prostaglandin E 2 synthesis was inhibited by the cyclooxygenase inhibitor indomethacin, reduced by dexamethasone, but only slightly decreased by the lipoxygenase inhibitor n…

Leukocyte chemotactic activity in cultures of unstimulated human lymphocytes.

2009

We have shown earlier that unstimulated human lymphocytes in in vitro cultures produce migration inhibitory factor into the supernatant. The evidence of spontaneous lymphokine synthesis is strengthened further by this study, which demonstrates leukocyte chemotactic activity in these culture supernatants. The factor has a molecular weight of more than 5000 daltons, it resisted heating for 15 min at 100 degrees C, and showed maximum activity at dilution 1:4-1:8 of the supernatants.

Effects of 1-(halogenalkoxy)alkyl-5-fluorouracil derivatives on cell growth, cell volume and nucleus size of mouse lymphoma cells.

1992

The effects of three 1-(halogenalkoxy)alkyl-5-fluorouracil derivatives on cultured mouse lymphoma cells were studied and compared with those of N-methyl-bis-(2-chloroethyl)amine hydrochloride (Lost). The derivatives exert only little influence on cell proliferation and cell volume. However, all derivatives cause a concentration-dependent nucleus contraction, probably due to DNA cross-linkings. Bromodesoxyuridine modulates the effects of the derivatives on the DNA, leading to swelling of the nucleus, which may be caused by DNA strand-breaks. It is suggested that the derivatives exert synergistic effects with other factors. It is concluded that these studies are suitable for the prescreening …

Lysine triggers apoptosis through a NADPH oxidase-dependent mechanism in human renal tubular cells

2012

Progressive chronic kidney disease (CKD) is common in lysinuric protein intolerance (LPI), a primary inherited aminoaciduria characterized by massive Lysine excretion in urine. However, by which mechanisms Lysine may cause kidney damage to tubule cells is still not understood. This study determined whether Lysine overloading of human proximal tubular cells (HK-2) in culture enhances apoptotic cell loss and its associated mechanisms. Overloading HK-2 with Lysine levels reproducing those observed in urine of patients affected by LPI (10 mM) increased apoptosis (+30%; p < 0.01 vs.C), as well as Bax and Apaf-1 expressions (+30-50% p < 0.05), while downregulated Bcl-2 (-40% p < 0.05). Apoptosis …