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PubMed2004

[The in vitro effect of norcantharidin on proliferation and invasion of human gallbladder carcinoma GBC-SD cells and its mechanism].

OBJECTIVE: To study the effect and mechanism of action of norcantharidin on proliferation and invasion of GBC-SD cells. METHODS: GBC-SD cells of human gallbladder carcinoma were cultured by cell culture technique. The tetrazolium-based colorimetric assay was used to evaluate cell growth. The Matrigel experiment and the crossing-river test were used to examine the invasiveness of GBC-SD cells. Expression of MMP(2), TIMP(2), PCNA and Ki-67 proteins of GBC-SD cells was determined by streptavidin-biotin complex method. RESULTS: Norcantharidin inhibited the growth and proliferation of GBC-SD cells in a dose and time dependent manner, with an IC(50) value of 56.18 micro g/ml at 48 h. The Matrigel experiment showed that norcantharidin began to inhibit the in vitro invasion of GBC-SD cells at the concentration of 5 micro g/ml. At 40 micro g/ml, the invasive action of GBC-SD cells was inhibited completely and their crossing-river time was prolonged significantly. After treatment with norcantharidin, the expression of PCNA, Ki-67, MMP(2) was significantly decreased. With the increase in TIMP(2) expression, the MMP(2) to TIMP(2) ratio was decreased significantly (P < 0.05). CONCLUSION: Norcantharidin inhibits the in vitro proliferation and growth of human gallbladder carcinoma cells at relatively low concentrations by inhibiting PCNA and Ki-67 expression. Its anti-invasive activity may be the results of decrease in MMP(2) to TIMP(2) ratio and reduced cell motility.

Antineoplastic Agents↗

PubMed1990

Inhibition of ribonucleotide reductase and growth of human colon carcinoma HT-29 cells and mouse leukemia L1210 cells by N-hydroxy-N'-aminoguanidine derivatives.

A series of N-hydroxy-N'-aminoguanidine (HAG) derivatives were studied and compared for their effects on ribonucleotide reductase activity in cell-free extracts; on nucleic acid synthesis and the growth of human colon carcinoma HT-29 cells; and on mouse leukemia L1210 cells in culture. The HAG derivatives [RCH=NNHC(=NH)NHOH-tosylate] studied could be grouped as: (1) hydroxybenzylidines; (2) methoxybenzylidines; and (3) nitrobenzylidines substituted at the R position. 2'-Hydroxybenzylidine-HAG, the lead compound, was relatively active in both HT-29 cells and L1210 cells (20 +/- 5 and 13 +/- 4 microM for 50% inhibition of HT-29 and L1210 cell growth respectively). The monohydroxybenzylidene compounds were generally more active than the dihydroxy- and trihydroxybenzylidene-HAG derivatives. The methoxybenzylidene-HAGs were as active as the monohydroxybenzylidene-HAGs. 2'-Hydroxy-4'-methoxybenzylidene-HAG was much more active than 2',4'-dihydroxybenzylidene-HAG. The mononitrobenzylidene-HAGs were more active than the dinitrobenzylidene-HAG compound. In general, L1210 cells were more sensitive to the effects of the HAG compounds than were HT-29 cells. There was good agreement between the concentration of drug required to inhibit the growth of HT-29 cells and that required to inhibit the growth of L1210 cells. There was also good correlation between the ability of HAG derivatives to inhibit ribonucleotide reductase activity and to inhibit tumor cell growth. Some derivatives, such as 2',3',4'- and 3',4',5'-trihydroxybenzylidene-HAG inhibited L1210 cell growth by 50% at lower concentrations (7.8 and 11.9 microM respectively) than the concentrations needed for 50% inhibition of HT-29 cell growth (196 and 234 microM respectively) and ribonucleotide reductase activity (122 and 188 microM respectively). The studies of nucleic acid synthesis in L1210 cells using [3H]cytidine as a precursor showed that 2',3',4'-trihydroxybenzylidine-HAG inhibited DNA synthesis at a lower concentration (29 microM for 50% inhibition) than was needed for the inhibition of RNA synthesis and formation of [3H]deoxycytidine nucleotides in the acid-soluble fraction (320 and 820 microM for 50% inhibition respectively). These results indicate that 2',3',4'-trihydroxybenzylidine-HAG inhibits DNA synthesis in L1210 cells through other mechanisms rather than exclusively through the inhibition of ribonucleotide reductase activity.

Animals↗

PubMedDate not supplied

Tgf-beta1 induced by high glucose is controlled by angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker on cultured human peritoneal mesothelial cells.

BACKGROUND: Loss of peritoneal function is a major complication associated with long-term peritoneal dialysis. Observed changes include loss and degeneration of the mesothelium, submesothelial thickening, alterations in the structure and number of blood vessels, and reduplication of the vascular basement membrane. Exposure to high glucose concentrations in peritoneal dialysis solutions is known to cause injury to cultured human peritoneal mesothelial cells (HPMC) as a result of overexpression of transforming growth factor beta 1 (TGF-beta1). Previous studies have demonstrated that angiotensin II (AII) increases expression of TGF-beta1 in a number of different cell types; although this has not been demonstrated in HPMC. OBJECTIVE: To clarify possible mechanisms involved in peritoneal fibrosis, we investigated whether HPMC expressed AII-forming pathway mRNA and whether increases in AII induced by high glucose contribute to the production of TGF-beta1. We also examined the effects of the angiotensin-converting enzyme inhibitor (ACEI) perindoprilat and the AII receptor blocker (ARB) candesartan on expression of TGF-beta1 and proliferation of HPMC. METHODS: Expression of mRNA for the AII-forming pathway and TGF-beta1 in HPMC was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative RT-PCR. Levels of AII and TGF-beta1 following 48 hours of incubation of the cells in a range of glucose concentrations were measured by enzyme immunoassay and enzyme linked immunosorbent assay respectively. The effect of glucose on cell proliferation was examined using the water-soluble tetrazolium salt WST-1 and [3H]-thymidine uptake. We also investigated the effect of ACEI and ARB on the expression of TGF-beta1 and the proliferation of HPMC incubated at high glucose for 48 hours. RESULTS: AII-forming pathway mRNA was detected in HPMC, with expression of angiotensinogen, angiotensin-converting enzyme (ACE), AII type 1 receptor, and TGF-beta1 mRNA increasing following exposure to glucose according to glucose concentration. High glucose was also shown to increase the production of All and TGF-beta1 and decrease the proliferation of HPMC. In contrast, we found that both the ACEI and the ARB attenuated the increase in TGF-beta1 production and reduced cell proliferation caused by exposure to high glucose. These effects were greater with a combination of the two drugs. CONCLUSION: The present study provides evidence that (1) HPMC express mRNA for the AII-forming pathway; (2) ACEI and ARB inhibit the TGF-beta1 production induced by high glucose; (3) the AII-forming pathwayis one mechanism by which high glucose causes production of TGF-beta1. In addition to having antihypertensive and renal-protective effects, combination therapy with an ACEI and an ARB may also be effective in preventing loss of peritoneal function and decreasing peritoneal fibrosis.

Angiotensin II↗

PubMed2006

Induction of G2/M phase arrest and apoptosis by a novel enediyne derivative, THDB, in chronic myeloid leukemia (HL-60) cells.

(Z)-2-(6-(Thieanisyl-2-yl)hexa-3-en-1,5-diynyl)benzenamine (THDB), an enediyne compound, was identified in our laboratory as a novel antineoplastic agent with broad spectrum of antitumor activities against many human cancer cells. THDB was found to inhibit the growth of HL-60 cells in a time-and dose-dependent manner. Cell cycle analysis showed G2/M phase arrest in HL-60 cells following 48 h exposure to THDB. Analysis of the cell cycle regulatory proteins demonstrated that THDB did not change the steady-state levels of cyclin B1, cyclin E, Cdk1 and Cdc25C, but decreased the protein levels of Cdk2 and cyclin A. THDB also caused a marked increase in apoptosis, as characterized by DNA fragmentation (DNA ladder and sub G1 formation), and poly (ADP-ribose) polymerase (PARP) cleavage, which was associated with activation of caspase-3, caspase-8 and caspase-9. Moreover, the THDB-induced apoptosis was significantly attenuated in the presence of specific inhibitors of caspase-3, -8 and -9. These molecular alterations provide an insight into THDB-caused growth inhibition, G2/M arrest and apoptotic death of HL-60 cells.

Actins↗

PubMed2007

Cytotoxic effect of spermine on retinal pigment epithelial cells.

PURPOSE: A prior study showed inactivation of ornithine-delta-aminotransferase (OAT)-deficient human retinal pigment epithelial (RPE) cells by a specific irreversible inhibitor (5-fluoromethylornithine; 5-FMO) leading to cell death, in an in vitro model of gyrate atrophy (GA) of the choroid and retina. In the present study, the cytotoxicity of metabolites of ornithine, especially spermine, in RPE cells was investigated, to clarify the mechanism of ornithine cytotoxicity in RPE cells. METHODS: RPE cells were incubated with ornithine or compounds involved in ornithine metabolic pathways. The effects on RPE cell viability and proliferative activity were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric and [(3)H]thymidine incorporation assays. Incorporation of spermine into RPE cells was examined by using [(14)C]spermine and dansyl-spermine. To assess spermine-induced RPE cell death, cells were double stained with annexin V and propidium iodide and subjected to flow cytometry. RESULTS: Ornithine, arginine, glutamate, proline, creatine, glycine, and putrescine exhibited no effects on the viability and proliferative activities of RPE cells, whereas spermidine and spermine (10 mM) inhibited [(3)H]thymidine incorporation by 13% and 89%, respectively. The inhibition of [(3)H]thymidine incorporation by spermine was dose dependent and was observed as early as 4 hours after addition. Further, spermine was incorporated and accumulated in the perinuclear region of RPE cells. Apoptotic RPE cell death was induced by spermine in a dose-dependent manner. CONCLUSIONS: The present results demonstrated that excessive spermine is cytotoxic to RPE cells and suggest that metabolites of ornithine, especially spermine, may be involved in the mechanism of RPE degeneration in GA.

Animals↗

PubMed2006

Neuroprotective effect of N-acetylcysteine on neuronal apoptosis induced by a synthetic gingerdione compound: involvement of ERK and p38 phosphorylation.

Besides being used as a spice, ginger has been applied in oriental medicine to ameliorate symptoms such as inflammatory, rheumatic disorders, and gastrointestinal discomforts. The effects of ginger on neuronal cells, however, have not been explored. We investigate the effect of 1-(3,4-dimethoxyphenyl)-3,5-dodecenedione (I(6)), a derivative of gingerdione, on cultured cortical neurons. After a 5-day maturation period in vitro, cortical neurons were treated with I(6) for 24 hr and cell viability was assessed using MTT assay. I(6) induced neuronal death in a concentration-dependent manner. Hoechst 33342, propidium iodide (PI), and TUNEL staining confirmed that the reduced cell viability by I(6) was due to apoptosis. Pre-treatment of cell with N-acetylcysteine (NAC) prevented cell death in a concentration-dependent manner. N-acetylcysteine increased phosphorylated levels of p42 and p44 extracellular signal-regulated kinases (ERKs). In parallel, farnesyltransferase and MEK inhibitors blocked ERK phosphorylation and neuroprotective effect of NAC. Unexpectedly, NAC also increased phosphorylated level of p38 mitogen-activated protein kinase (MAPK) and p38 specific inhibitors dose-dependently attenuated the effect of NAC. Farnesyltransferase and MEK inhibitors completely abolished NAC-induced p38 phosphorylation whereas p38 inhibitor did not influence NAC-induced ERK phosphorylation. These results show that NAC serially activates ERKs and p38 MAPK, and ERKs and p38 work together to mediate the neuroprotective effect of NAC.

Acetylcysteine↗

PubMed2005

Beneficial effect of flavonoid baicalein in cisplatin-induced cell death of human glioma cells.

Flavonoids are a family of polyphenolic compounds found ubiquitously in fruits and vegetables as well as in food products and beverages derived from plants. Baicalein is a flavonoid extracted from the root of Scutellaria baicalensis Georgi, a medicinal plant traditionally used in Oriental medicine. Baicalein exerts either proapoptotic or anti-apoptotic effects in different cell types. The present study was, therefore, undertaken to examine the effect of baicalein on cisplatin-induced apoptosis of human glioma cells. Cisplatin resulted in cell death in a dose- and time-dependent manner and the cell death was attributed to apoptosis. Baicalein prevented loss of cell viability and apoptosis induced by cisplatin in a dose-dependent fashion over the concentrations of 2-10 microM. Exposure of cells to baicalein without cisplatin did not affect cell viability. Western blot analysis demonstrated that cisplatin induced activation of extracellular signal-regulated kinase (ERK), which was not affected by baicalein. Baicalein prevented Bax expression, mitochondrial depolarization, cytochrome c release from mitochondria, and caspase activation induced by cisplatin. Taken together, these findings suggest that baicalein prevents cisplatin-induced apoptosis through inhibition of the mitochondrial depolarization in human glioma cells.

Antineoplastic Agents↗

PubMed2003

Ursolic acid induces apoptosis through caspase-3 activation and cell cycle arrest in HaCat cells.

Ursolic acid (UA) is a pentacyclic triterpene compound isolated from many kinds of medicinal plants and present in human diet. In this study, we investigated the pro-apoptotic effect of UA on HaCat derived keratinocyte cell line. Treatment with UA decreased the viability of HaCat cells in a concentration- and time-dependent manner. In addition, cell cycle analysis revealed that UA treated HaCat cells were blocked predominantly in G1 phase. Moreover, expression of p21WAF1, a cell cycle regulator, was increased by UA, indicating that UA-induced cell cycle arrest could be mediated through p21WAF1. During UA treatment, we also demonstrated that p53 was phosphorylated at serine 392 and translocated to the nucleus. It is well established that p53 achieves its tumor suppressor activity by inducing apoptosis on cells. To define the apoptotic process in our system, we examined effect of UA on caspase activities, and demonstrated caspase-3 activation. In conclusion, our results suggest that UA induces: i) cell cycle arrest concomitantly with the apparition of the apoptotic sub group G1 peak, and ii) cell death through apoptosis, which is mediated by caspase-3.

Apoptosis↗

PubMed2006

Biphosphinic palladacycle complex mediates lysosomal-membrane permeabilization and cell death in K562 leukaemia cells.

The cell death mechanism of cytotoxicity induced by the Biphosphinic Palladacycle Complex (BPC) was studied using a K562 leukaemia cell line. The IC50 values obtained for K562 cells post-72 h of BPC were less than 5.0 microM by using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and trypan blue assays. Using the Acridine Orange vital staining combining fluorescence microscopy it was observed that the complex triggers apoptosis in K562 cells, inducing DNA fragmentation, as analysed through electrophoresis. Lysosomal-membrane permeabilization was also observed in K562 cells post-5 h of BPC, which suggests intralysosomal accumulation by proton-trapping, since its pKa value ranged from 5.1 to 6.5. Caspase-3, and -6 activity induced by BPC in K562 cells was prevented by the cathepsin-B inhibitor [N-(L-3-trans-propylcarbamoyl-oxirane-2-carbonyl)-L-isoleucyl-L-proline] (CA074). These events occurred in the presence of endogenous bcl-2 and bax expression. Acute toxicological studies demonstrated that BPC produces no lesions for liver and kidney fourteen-days after drug administration (100 mg/kg--i.p.). White and red blood cells of BPC-treated mice presented normal morphological characteristics. Taken together, these data suggest a novel lysosomal pathway for BPC-induced apoptosis, in which lysosomes are the primary target and cathepsin B acts as death mediator.

Animals↗

PubMed2006

Fullerene-based amino acid nanoparticle interactions with human epidermal keratinocytes.

The functionalization of C(60) with such complexes as amino acids has the potential to provide greater interaction between the fullerene and the biological environment yielding potential new medical and pharmacological applications. Although scientific research in the past decade has revealed much about the chemical and physical properties of C(60), the biological activities of this compound and its derivatives are still relatively unclear. In an attempt to understand the biological activity of functionalized C(60), human epidermal keratinocytes (HEK) were exposed to fullerene-based amino acid (Baa) solutions ranging in concentrations of 0.4-0.00004 mg/mL in a humidified 5% CO(2) atmosphere at 37 degrees C. MTT cell viability after 48 h significantly decreased (p<0.05) for concentrations of 0.4 and 0.04 mg/mL. In an additional study, human cytokines IL-6, IL-8, TNF-alpha, IL-1beta, and IL-10 were assessed for concentrations ranging from 0.4-0.004 mg/mL. Media was harvested at 1, 4, 8, 12, 24 and 48 h for cytokine analysis. IL-8 concentrations for the 0.04 mg/mL treatment were significantly greater (p<0.05) than all other concentrations at 8, 12, 24, and 48 h. IL-6 and IL-1beta activities were greater at the 24h and 48 h for 0.4 and 0.04 mg/mL. No significant TNF-alpha or IL-10 activity existed at any time points for any of the concentrations. These results indicate that concentrations lower than 0.04 mg/mL initiate less cytokine activity and maintain cell viability. In HEK, Baa concentrations of 0.4 and 0.04 mg/mL decrease cell viability and initiate a pro-inflammatory response.

Amino Acids↗

PubMed2001

N-acetyl-L-cysteine protects SHSY5Y neuroblastoma cells from oxidative stress and cell cytotoxicity: effects on beta-amyloid secretion and tau phosphorylation.

Redox changes within neurones are increasingly being implicated as an important causative agent in brain ageing and neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD) and Alzheimer's disease (AD). Cells have developed a number of defensive mechanisms to maintain intracellular redox homeostasis, including the glutathione (GSH) system and antioxidant enzymes. Here we examine the effects of N-acetyl-L-cysteine (NAC) on beta-amyloid (A beta) secretion and tau phosphorylation in SHSY5Y neuroblastoma cells after exposure to oxidative stress inducing/cytotoxic compounds (H(2)O(2), UV light and toxic A beta peptides). A beta and tau protein are hallmark molecules in the pathology of AD while the stress factors are implicated in the aetiology of AD. The results show that H(2)O(2), UV light, A beta 1-42 and toxic A beta 25-35, but not the inactive A beta 35-25, produce a significant induction of oxidative stress and cell cytotoxicity. The effects are reversed when cells are pre-treated with 30 mM NAC. Cells exposed to H(2)O(2), UV light and A beta 25-35, but not A beta 35-25, secrete significantly higher amounts of A beta 1-40 and A beta 1-42 into the culture medium. NAC pre-treatment increased the release of A beta 1-40 compared with controls and potentiated the release of both A beta 1-40 and A beta 1-42 in A beta 25-35-treated cells. Tau phosphorylation was markedly reduced by H(2)O(2) and UV light but increased by A beta 25-35. NAC strongly lowered phospho-tau levels in the presence or absence of stress treatment.

Acetylcysteine↗

PubMed2005

Suppression of inducible nitric oxide synthase and cyclooxygenase-2 expression in RAW 264.7 macrophages by sesquiterpene lactones.

The molecular mechanism underlying the suppression of lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma)-induced nitric oxide (NO) and prostaglandin (PG) E(2) production was investigated in RAW 264.7 macrophages treated with sesquiterpene lactones, zaluzanin-C and estafiatone, isolated from Ainsliaea. Zaluzanin-C and estafiatone decreased NO production in LPS/IFN-gamma-stimulated RAW 264.7 macrophages with an IC50 of about 6.61 microM and 3.80 microM, respectively. In addition, these compounds inhibited the synthesis of PGE(2) in LPS/IFN-gamma-treated RAW 264.7 macrophages. Furthermore, treatment with zaluzanin-C and estafiatone resulted in a decrease in inducible No Synthase (iNOS) and Cyclooxygenase-2 (COX-2) protein and mRNA expression levels. Zaluzanin-C and estafiatone inhibited nuclear factor-kappaB (NF-kappaB) activation, a transcription factor necessary for iNOS and COX-2 expression in response to LPS/IFN-gamma. This effect was accompanied by parallel reduction of phosphorylation and degradation of inhibitor of kappaB (IkB). In addition, these effects were completely blocked by treatment with cysteine, indicating that the inhibitory effect of zaluzanin-C and estafiatone might be mediated by alkylation of either NF-kappaB itself or an upstream molecule of NF-kappaB. These results demonstrate that the suppression of NF-kappaB activation by zaluzanin-C and estafiatone might be attributed to inhibition of nuclear translocation of NF-kappaB resulting from blockade of the degradation of IkappaB, leading to suppression of the expression of iNOS and COX-2, which play important roles in inflammatory signaling pathways.

Animals↗

PubMed2004

Cytotoxic effects of gingival retraction cords on human gingival fibroblasts in vitro.

The objective of this study was to determine the cytocompatibility of three different extracts of gingival retraction cords and to compare the cytotoxic effect of these materials on human gingival fibroblasts. Gingival retraction cords impregnated with aluminium sulphate (Gingi-Aid), dl-adrenaline HCl (Gingi-Pak) and non-drug-impregnated cord (Gingi-Plain) were eluted with culture medium for 10 min and 24 h. Cytotoxicity was judged using a tetrazolium bromide reduction assay. Our data demonstrated that gingival retraction cords applied alone almost completely inhibited cell viability (P < 0.05). In addition, the results also showed that the eluates from aluminium sulphate-impregnated cord, dl-adrenaline HCl-impregnated cord and non-drug-impregnated cord were cytotoxic to primary human gingival fibroblast cultures (P < 0.05). The cell viability of incubation of gingival fibroblasts containing 10-min eluates of aluminium sulphate, dl-adrenaline HCl and non-drug-impregnated cord was 61, 21 and 70%, respectively. The cell viability of incubation of gingival fibroblasts containing 24 h eluates of aluminium sulphate, dl-adrenaline HCl and non-drug-impregnated cord was 68, 58 and 72%, respectively. It was found that dl-adrenaline HCl-impregnated gingival retraction cord was the most toxic gingival retraction cord among the materials tested in all cultures (P < 0.05). The cytotoxicity decreased in an order of dl-adrenaline HCl-impregnated cord > aluminium sulphate-impregnated cord > non-drug-impregnated cord. The extent or degree of the cytotoxicity depended on the materials tested. Gingival retraction cords have significant potential for gingival toxicity. Careful management of gingiva retraction cords would lower the risk of potential gingival tissue damage during clinical application procedure and thus increase the success of prosthodontic procedures.

Alum Compounds↗

PubMed1997

Antiproliferative effect of curcumin (diferuloylmethane) against human breast tumor cell lines.

Pharmacologically safe compounds that can inhibit the proliferation of tumor cells have potential as anticancer agents. Curcumin, a diferuloylmethane, is a major active component of the food flavor turmeric (Curcuma longa) that exhibits anticarcinogenic properties in vivo. In vitro, it suppressed c-jun/Ap-1 and NF-kappaB activation and type 1 human immunodeficiency virus long-terminal repeat-directed gene expression. We examined the antiproliferative effects of curcumin against several breast tumor cell lines, including hormone-dependent and -independent and multidrug-resistant (MDR) lines. Cell growth inhibition was monitored by [3H]thymidine incorporation, Trypan blue exclusion, crystal violet dye uptake and flow cytometry. All the cell lines tested, including the MDR-positive ones, were highly sensitive to curcumin. The growth inhibitory effect of curcumin was time- and dose-dependent, and correlated with its inhibition of ornithine decarboxylase activity. Curcumin preferentially arrested cells in the G2/S phase of the cell cycle. Curcumin-induced cell death was neither due to apoptosis nor to any significant change in the expression of apoptosis-related genes, including Bcl-2, p53, cyclin B and transglutaminase. Overall our results suggest that curcumin is a potent antiproliferative agent for breast tumor cells and may have potential as an anticancer agent.

Antibiotics, Antineoplastic↗

PubMed2006

Effects of poly-L-arginine on the permeation of hydrophilic compounds through surface ocular tissues.

We investigated whether poly-L-arginine (PLA) could improve permeation of the hydrophilic compounds, FITC-labeled dextran (MW 3800, FD-4) and pyridoxamine, through ocular surface tissues. Samples of cornea, conjunctiva, or conjunctiva/sclera composite from Japanese white rabbits were mounted in Ussing chambers to measure FD-4 and pyridoxamine permeation and transepithelial electric resistance (TEER). The integrity and viability of the conjunctiva were assessed by chronological TEER monitoring and MTT assay, respectively. The permeability coefficient (Papp) of FD-4 in the cornea, conjunctiva, and conjunctiva/sclera composite was increased by the addition of PLA (MW 38 kDa, PLA (50) at 0.1 mg/ml by 6.81-, 9.78-, and 7.91-fold, respectively. The Papp of pyridoxamine was also increased in the presence of PLA (50) by 7.98-, 4.67-, 8.31-fold, respectively. A corresponding reduction in TEER was observed in all tissues. However, the reduced TEER in the case of the conjunctiva had recovered to ca. 70% 120 min after replacing the mucosal fluid with fresh bicarbonated Ringer's solution. MTT assay results indicated that treatment of the conjunctiva with 0.1 mg/ml PLA (50) did not change the production of formazan compared to that without PLA (50), indicating that the conjunctival viability is not significantly affected by PLA (50). Our findings suggest that PLA may be useful in promoting the ocular delivery of hydrophilic drugs without producing significant epithelial damage.

Animals↗

PubMedDate not supplied

[The cytochemical characteristics of neutrophilic leukocytes in the peripheral blood and synovial fluid of patients with rheumatoid arthritis in the course of treatment].

The authors studied the activity of alkaline and acid phosphatase (AP), myeloperoxidase (MP), the level of cationic protein (CP), spontaneous and pyrogenal-induced tests of restoration of nitroblue of tetrazolium (HCT-test) in the blood and synovial fluid (SF) neutrophils in 116 patients with rheumatoid arthritis (RA) in the dynamics of a 3-4-week and subsequent 6-month therapy with chrysanol, salazopyridazine and delagil. In the active phase all the patients exhibited an abrupt increase in the activity of alkaline and acid phosphatase in blood neutrophils, a drop in the level of CP (in 69%), a rise in the activity of MP (in 32%); pyrogenal did not induce any capacity for restoring HCT (in 44%). Indices of alkaline and acid phosphatase in blood and SF neutrophils and also of the induced TCT-test in blood neutrophils correlated with the degree of RA activity. Statistically significant positive cytochemical shifts were noted only after 6 months of treatment: a decrease in alkaline and acid phosphatase activity, a rise in the level of CP, MP and capacity for restoration pf HCT with pyrogenal in blood neutrophils. Increase in the correlation of CP or MP levels by 0.2 or more in blood and SF neutrophils, and also of the normal level of CP in blood neutrophils or its increase not less than by 15% 3-4 weeks after the beginning of therapy evidence good prognostic informativeness with respect to the effectiveness of basic therapy.

Adolescent↗

PubMed2004

Genotoxicity of the isoflavones genistein, daidzein and equol in V79 cells.

Hormonally active chemicals in the human diet, such as man-made estrogenic chemicals or plant-derived compounds (phytoestrogens), have become a matter of public concern. A significant part of human exposure to phytoestrogens is attributable to soy isoflavones. Besides their estrogenic properties, soy isoflavones also exert genotoxic actions. In this paper, the micronucleus (MN) assay in V79 cells was used to study chromosomal genotoxicity. Genistein caused a clear dose-related induction of MN within the range of 5-25 microM; MN rates were declining at higher genistein concentrations. This was probably due to cytotoxicity of genistein since reduced neutral red uptake and MTT formation with an IC(50) of about 75 microM occurred. Daidzein induced a comparatively shallow increase in the number of MN between 25 and 100 microM. In contrast, the daidzein metabolite equol caused an increase in the number of MN up to 25 microM with no further increase at higher concentrations. Additional staining with anti-kinetochore (CREST) antibodies served to determine if the micronuclei contain whole chromosomes or acentric fragments. Genistein induced mostly CREST(-) micronuclei, i.e. MN with chromosomal fragments, thus indicative of a clastogenic mode of action. MN induced by high concentrations of daidzein were partly CREST(+) and CREST(-), whilst equol induced mostly CREST(+) micronuclei indicative of an aneugenic action. These results point to a differential genotoxicity of phytoestrogens.

Animals↗

PubMed2002

The apoptotic effect of HA14-1, a Bcl-2-interacting small molecular compound, requires Bax translocation and is enhanced by PK11195.

HA14-1 is a small molecular compound that was identified based on the structure of Bcl-2. HA14-1 interacts with Bcl-2 and inhibits the antiapoptotic effect of Bcl-2. We investigated the mechanism of HA14-1-induced apoptosis and found that HA14-1 induces translocation of Bax from cytosols to the mitochondria. Cells deficient in Bax were much more resistant to HA14-1-induced apoptosis, suggesting that Bax is required for this process. A pan-caspase inhibitor failed to inhibit the apoptotic effect of HA14-1, indicating that this is through a caspase-independent pathway. To eliminate the effect of cytosolic Bax, we incubated cell-free mitochondria with HA14-1 to study its effect on cytochrome c release. HA14-1 was ineffective in causing cytochrome c release from the purified mitochondria. However, the combination of HA14-1 and PK11195, an antagonist of peripheral benzodiazepine receptor of the mitochondria, enhanced the cytochrome c release by HA14-1. The combination of PK11195 and HA14-1 could therefore serve as a potentially useful approach to enhance apoptosis in cancer.

Animals↗