Alteration of radiation-sensitive processes associated with cancer and longevity by dietary 2-mercaptoethanol.

BACKGROUND: Previous results demonstrated dietary 2-mercaptoethanol (2-ME) delayed appearance of cancer in certain murine strains. In addition, it had a benefit not found with other organosulfurs, in that it completely prevented spontaneous development of cancer in BXSB-Yaa + over an entire lifespan. AIMS: These benefits raise the question: What, if any, alteration of radiation-induced tumorigenesis would 2-ME impart that may differ from that of other sulfur antioxidants? This is relevant based on the extensive use of radiation in diagnoses and therapy and 2-ME's superior in vitro and in situ immune enhancement properties. MATERIALS AND METHODS: This was addressed by exposing long-lived, B10.A (4R) mice to sublethal, 5.5 Gy ionizing gamma-rays and then tumor development monitored over a lifetime. STATISTICAL ANALYSIS: Two-tailed P-values were determined using the Fischer's Exact Test. RESULTS: The only tumors detected were mammary and only in animals that were both exposed to radiation and not treated with 2-ME. The 43% incidence differed significantly from the absence of tumors in non-irradiated mice that were or were not exposed to 2-ME and in those irradiated and treated daily with 2-ME, irrespective of whether treatment was started prior to or post irradiation. However, quite unexpectedly, radiation shortened longevity 29% from undefined causes, including cancer, in animals pretreated with 2-ME; longevity was not altered in those not pretreated or if treatment was started post-irradiation. CONCLUSIONS: The findings have relevance for cancer prevention and the controversy relative to ''long term survival/safety'' of currently used antioxidants as free radical scavengers in humans undergoing radiotherapy.

Evidences for the existence of intermolecular disulfide-bonded oligomers in the H3 hemagglutinins expressed in insect cells.

The hemagglutinin (HA) protein as the predominant antigen, executes receptor binding and membrane fusion, which critically influence the virological characteristics of influenza viruses. The literature contained scattered data showing reduction-sensitive HA oligomers when HA proteins were analyzed under non-reducing conditions. However, whether the reduction-sensitive HA oligomers are inter-monomer disulfide-bonded has not been studied. Here, we showed: (1) the detection of ß-mercaptoethanol-sensitive H3 HA oligomers was not affected by the treatment of cells with iodoacetamide prior to cell solubilization; (2) H3 HA oligomers were present on cell surfaces; (3) H3 HA oligomers had higher density than monomers; and (4) mutation of all the five C-terminal cysteines completely abolished the formation of H3 HA oligomers. Furthermore, mutant HAs with mutations of TM cysteines, CT cysteines or all five cysteines had decreased thermal stability but increased fusion activity in comparison with wildtype HA. In conclusion, this study has presented enough evidence for the existence of inter-monomer S-S H3 HA oligomers formed by five C-terminal cysteines, and suggested that all five C-terminal cysteines exerted opposite effects on HA thermal stability and fusion activity.

Dietary supplemented 2-mercaptoethanol prevents spontaneous and delays virally-induced murine mammary tumorigenesis.

There seems to be little doubt that organosulfur compounds have enormous benefits for biological processes, especially those of diseases like cancer. The preliminary results herein define a cancer model in which benefits/mechanisms of multitudes of xenobiotic and nature's organosulfurs could easily be compared. Mice from three strains with a high incidence for naturally occurring tumors were treated daily with 2-mercaptoethanol (2-Me) starting at weaning. The 100% tumor incidence of undefined etiology in untreated BXSB-Yaa (+) males was completely prevented by 2-Me. In contrast, 2-Me treatment of female and male C3H.OL and C3H.OH congenic strains, did not change the 100% tumor incidence due to milk-borne retrovirus, MMTV(S), but did: (1) delay the appearance of tumors by 42%; (2) increase longevity 56%; and (3) increase longevity, post-tumor detection, 95%. The addition of these results to the increasingly impressive anti-cancer benefits of simple xenobiotic organosulfurs raise the question: Can they be adapted for use as a preventive modality for human cancer?

Alteration of GI symptoms in a cow with Johne disease by the dietary organosulfur, 2-mercaptoethanol.

Sub-phenotypes of inflammatory bowel disease (IBD)-Crohn disease, ulcerative colitis and some cases of irritable bowel syndrome-are generally considered a consequence of gastrointestinal inflammation of unknown etiology. Conventional therapy and more recently biologic agents, all with varying degrees of drawbacks, have resulted in improved control of these diseases. However, as the incidence and prevalence continue to rise, needs for prevention, permanent remission and cures remain unmet, plus there still remain needs for improved control of symptoms, such as pain and diarrhea. The case report herein describes a serendipitous, novel means for curtailing these symptoms associated with a bovine gastrointestinal disease that may have applicability for patients with diseases characterized by abdominal-visceral pain and diarrhea.

In vitro neuronal induction of adipose-derived stem cells and their fate after transplantation into injured mouse brain.

The effect of substances known as inducers of neuronal differentiation on cultured human and mouse adipose-derived mesenchymal stem cells (ASCs) and their fate after transplantation into the injured and ischemic mouse brains were studied. ASCs were isolated from the human and mouse adipose tissue. Inducers of neuronal differentiation included ß-mercaptoethanol, glial cell line-derived neurotrophic factor (GNDF), brain-derived neurotrophic factor (BDNF), retinoic acid (RA), 5-azacytidine, as well as their combinations. Three days after the induction, the phenotype of the induced cells was analyzed using immunocytochemistry and real-time PCR assay for differential expression of specific genes. The induction efficiency was evaluated by the increased transcription of neuronal differentiation markers: nestin, ß-III-tubulin (Tub-B), microtubule-associated protein 2 (MAP2), and neuron-specific enolase (ENO2). The expression of marker genes was tested by immunocytochemical analysis. ASC cultivation in the medium with RA or BDNF in combination with 5- azacytidine for a week increased the mRNA and protein levels of nestin, Tub-B, and ENO2. The transplantation of induced mouse ASCs into the mouse brain increased the lifespan of the cells relative to control uninduced cells and promoted their migration from the transplantation site to the recipient cerebral parenchyma. The transplantation of the induced cells into the mouse brain pre-exposed to endothelin- 1 promoted a more active cell migration into the surrounding ischemic brain tissue. Thus, ASC exposure to RA or BDNF in combination with 5-azacytidine elevated the transcription of the neuronal differentiation markers and improved the viability and integration of ASCs grafted into the mouse brain.

Effect of the addition of beta-mercaptoethanol to a thawing solution supplemented with caffeine on the function of frozen-thawed boar sperm and on the fertility of sows after artificial insemination.

We have reported that artificial insemination (AI) with frozen-thawed boar semen supplemented with caffeine increased the number of uterine sperm by inhibiting the migration of polymorphonuclear leukocytes (PMNs) into the uterine lumen, thereby improving the fertility of gilts and sows. The objective of the present study was to examine the effects of the addition of the antioxidant beta-mercaptoethanol (bME) and caffeine to the thawing solution on the function of frozen-thawed sperm, on the phagocytic activity of PMNs for sperm, and on the fertility of sows after AI. When frozen-thawed sperm were cultured in the presence of 25 or 50 µm bME, sperm capacitation and spontaneous acrosome reactions were inhibited (P < 0.01). There was no effect of bME on phagocytic activity of PMNs for sperm in vitro. When hormonally treated (400 IU of equine chorionic gonadotropin + 200 IU of human chorionic gonadotropin) weaned sows experienced a single intrauterine insemination with frozen-thawed sperm (25 × 10(8) sperm per 50 ml dose) 40 h after subsequent hCG administration, pregnancy and farrowing rates were unaffected by the addition of 50 µm bME (pregnancy rate, 20 vs 21% in controls; farrowing rate, 20 vs 21%; n = 15 and 14, respectively). However, litter size tended to be higher than in the presence of 50 µm bME compared to its absence (10.0 ± 1.0 vs 5.7 ± 1.5, respectively; P < 0.07). Thus, the addition of bME to the thawing solution containing caffeine could be of benefit for improving the function of frozen-thawed sperm without influencing the phagocytic activity of PMNs for sperm. Although there were no statistically significant effects of bME on pregnancy or farrowing rates, the litter size tended to be higher in the sows subjected to a fixed-time single AI treatment with synchronized ovulation.

Bismuth-ethanedithiol incorporated in a liposome-loaded tobramycin formulation modulates the alginate levels in mucoid Pseudomonas aeruginosa.

OBJECTIVES: This study examined the antibacterial activity, alginate modulation, and deposition of a tobramycin bismuth-ethanedithiol (Tob-Bi) conventional (free) or vesicle-entrapped (lipo) formulation against two mucoid Pseudomonas aeruginosa clinical isolates. METHODS: The inhibitory, bactericidal and biofilm eradication concentrations (in presence or absence of alginate lyase) were determined. The modulation of alginate was assessed by the carbazole assay and fluorescent-labelling of live alginate-producing biofilms by confocal microscopy. The deposition of the formulations was assessed using the immunogold-labelling technique, transmission electron microscopy, and energy dispersive X-ray spectroscopy (EDS). KEY FINDINGS: The inhibitory and bactericidal concentrations for lipo Tob-Bi compared with free Tob-Bi were reduced in all strains by 2- to 8-fold, and 2- to 32-fold, respectively. The biofilm eradication concentrations for lipo Tob-Bi compared with free Tob-Bi were reduced by 4- to 32-fold in the mucoid strains. The addition of alginate lyase transiently enhanced eradication for one mucoid strain only. The alginate levels were attenuated by more than half, and free Tob-Bi fared better than lipo Tob-Bi determined by the carbazole assay. Under confocal microscopy, alginate lyase reduced alginate levels and detached mucoid biofilms. Free and lipo Tob-Bi did not detach the bacteria from the surface, but attenuated alginate levels. Tobramycin was detected by immunogold-labelling inside the bacterium, but EDS did not detect bismuth deposits. CONCLUSIONS: These findings substantiate a role in which tobramycin, bismuth, and alginate lyase play in eradicating mucoid P. aeruginosa growth and modulate alginate levels.

Porphyrin-magnetite nanoconjugates for biological imaging.

BACKGROUND: The use of silica coated magnetic nanoparticles as contrast agents has resulted in the production of highly stable, non-toxic solutions that can be manipulated via an external magnetic field. As a result, the interaction of these nanocomposites with cells is of vital importance in understanding their behaviour and biocompatibility. Here we report the preparation, characterisation and potential application of new "two-in-one" magnetic fluorescent nanocomposites composed of silica-coated magnetite nanoparticles covalently linked to a porphyrin moiety. METHOD: The experiments were performed by administering porphyrin functionalised silica-coated magnetite nanoparticles to THP-1 cells, a human acute monocytic leukaemia cell line. Cells were cultured in RPMI 1640 medium with 25 mM HEPES supplemented with heat-inactivated foetal bovine serum (FBS). RESULTS: We have synthesised, characterised and analysed in vitro, a new multimodal (magnetic and fluorescent) porphyrin magnetic nanoparticle composite (PMNC). Initial co-incubation experiments performed with THP-1 macrophage cells were promising; however the PMNC photobleached under confocal microscopy study. ß-mercaptoethanol (ß-ME) was employed to counteract this problem and resulted not only in enhanced fluorescence emission, but also allowed for elongated imaging and increased exposure times of the PMNC in a cellular environment. CONCLUSION: Our experiments have demonstrated that ß-ME visibly enhances the emission intensity. No deleterious effects to the cells were witnessed upon co-incubation with ß-ME alone and no increases in background fluorescence were recorded. These results should present an interest for further development of in vitro biological imaging techniques.

Obesity, longevity, quality of life: alteration by dietary 2-mercaptoethanol.

Previous investigations demonstrated that optimization of murine immunological reactivity in tissue culture required a sulfhydryl compound; the most effective being 2-mercaptoethanol (2-Me). Since these reports, 2-Me was found beneficial for both growth/function of other cell-types in vitro, including those of other species, and when fed orally, it impeded and/or reversed some in situ physiological changes associated with aging. More recently, thiol-containing compounds possessing oxidation-reduction potentials weaker than 2-Me were found to impart beneficial effects for many other, including human, diseases. Based on these effects, the research herein addressed the question: What consequences might dietary 2-Me impart on health and disease of mice other than those associated with aging? The main parameters monitored over the lifetime of individual animals exposed to dietary 10⁻³ M 2-Me in their drinking water were: quality of life (obesity and development of recumbent, emaciated and/or cachectic health); longevity; and appearance of tumors. Instead of anticipated toxic attributes, the following unique benefits were found; mean survival of a moderately-lived strain (A/J) was increased 40.8%, high-fat-diet obesity was curtailed in C57BL/10 mice, and a goal of aging intervention protocols, namely preventing loss of quality of life during aging (recumbent, emaciated and/or cachectic) was achieved. Various mechanisms are discussed as they pertain to these findings.

Longevity of SLE-prone mice increased by dietary 2-mercaptoethanol via a mechanism imprinted within the first 28 days of life.

In the preceding report, moderately lived-mice fed dietary 2-mercaptoethanol (2-Me) had their life extended, whereas long-lived mice were found to have the quality of life improved, but not extended, and did not develop high fat-diet obesity. In the present report, alteration of longevity of mice prone to develop spontaneous, systemic lupus erythematosus (SLE) by dietary 2-Me was determined. NZB, NZW, (NZW x NZB) F1-hybrid, BXSB/MpJ, BXSB-Yaa+/J, MRL/MpJ and MRL/MpJ-Faslpr mice received drinking water, without or with 2-Me at concentrations of 10⁻³ or 10⁻² M. Therapeutic benefit was assessed by changes in longevity. The median survival of MRL/MpJ males was increased from 443 to 615 days and those of (NZW x NZB) F1 and NZB males and females were increased approximately 2-fold. The most unexpected finding was that longevity of F1 males was significantly extended irrespective of whether dietary exposure to 2-Me was initiated at 28 days of age, at 50 days of age, or initiated during gestation (and then terminated at weaning--28 days of age). Survival of F1-hybrids in which treatment was initiated in utero or at 28 days of age was not significantly different, whereas if initiation was delayed until 50 days of age, survival was >200 days shorter. Survival of male MRL/MpJ-Fas lpr and BXSB/MpJ (Yaa-), two strains with genetically controlled accelerated SLE, was not altered by 2-Me when started at 50 days. Various alternatives are discussed regarding potential long-lasting mechanisms imprinted early in life. Even though present day treatments of rodent SLE are generally aimed at controlling specific immunological events, with or without survival benefits, or are procedures presently unsuitable for therapeutic use in humans, the findings presented herein seem worthy of clinical evaluation.

Effect of antioxidants during bovine in vitro fertilization procedures on spermatozoa and embryo development.

Increased amounts of reactive oxygen species (ROS) during in vitro fertilization (IVF) may cause cytotoxic damage to gametes, whereas small amounts of ROS favour sperm capacitation. The aim of this study was to investigate the effect of antioxidants [50 microm beta-mercaptoethanol (beta-ME) and 50 microm cysteamine (Cyst)] or a pro-oxidant (5 mm buthionine sulfoximine) on the quality and penetrability of spermatozoa into bovine oocytes and on the subsequent embryo development and quality when added during IVF. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes, and mitochondrial function, was diminished (p < 0.05) after 4-h culture in the presence of antioxidants. Oocyte penetration rates were similar between treatments (p > 0.05), but antioxidants adversely affected the normal pronuclear formation rates (p < 0.05). The incidence of polyspermy was high for beta-ME (p < 0.05). No differences were observed in cleavage rates between treatments (p > 0.05). However, the developmental rate to the blastocyst stage was adversely affected by Cyst treatment (p < 0.05). The quality of embryos that reached the blastocyst stage, evaluated by total, inner cell mass (ICM) and trophectoderm cell numbers and ICM/total cell ratio was unaffected (p > 0.05) by treatments. The results indicate that ROS play a role in the fertilizing capacity in bovine spermatozoa, as well as in the interaction between the spermatozoa and the oocytes. It can be concluded that supplementation with antioxidants during IVF procedures impairs sperm quality, normal pronuclear formation and embryo development to the blastocyst stage.

Viability and growth of buffalo preantral follicles and their corresponding oocytes in vitro: effect of growth factors and beta mercaptoethanol.

The present study was undertaken to isolate buffalo preantral follicles (PFs), to test the viability and sizes of buffalo PFs and to examine the effect of various growth factors (insulin-like growth factor, fibroblast growth factor) and an antioxidant (beta mercaptoethanol) on the in vitro growth, survival and antrum formation rates of buffalo PFs and growth rates of oocytes in cultured PFs. Preantral follicles from slaughtered buffalo ovaries were recovered by a combined mechanical and enzymatic method. The recovery rates of >40-100, 101-200, 201-300, 301-400 and 401-500 microm PFs were 5.1, 3.2, 3.1, 6.3 and 5.1 per ovary, respectively. The corresponding viability rates were 76.1%, 78.1%, 85.2%, 92.5% and 92.6%, respectively. There was a positive correlation (r = 0.73) between oocyte size and the follicular size. However, there was no significant correlation between the size of oocyte and its viability at the time of its retrieval from ovary. Insulin-like growth factor and fibroblast growth factor improved the survival of buffalo PFs and regulated their growth in culture. The growth factors and beta mercaptoethanol in association synergically improved the growth and survival of buffalo PFs.

Liposomal bismuth-ethanedithiol formulation enhances antimicrobial activity of tobramycin.

Pseudomonas aeruginosa and Burkholderia cenocepacia (formally, genomovar III genotype of Burkholderia cepacia complex) have emerged as serious opportunistic resistant pathogens in patients with cystic fibrosis (CF). We have developed a liposomal formulation containing bismuth-ethanedithiol (BiEDT) and tobramycin to overcome bacterial resistance. The stability of liposomal BiEDT-tobramycin (LipoBiEDT-TOB) was studied in phosphate buffered saline (PBS) and human pooled plasma at 4 and 37 degrees C. Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) for free tobramycin and LipoBiEDT-TOB against clinical isolates of P. aeruginosa and B. cenocepacia were determined by the broth dilution method. The toxicity profile and the influence on bacterial adhesion of LipoBiEDT-TOB formulation were determined using a human lung carcinoma cell line (A549). LipoBiEDT-TOB exhibited lower MICs than the conventional antibiotic (0.25mg/L vs. 1024 mg/L) and eradicated this highly resistant bacterial strain of P. aeruginosa (PA-48913) at very low concentrations (4 mg/L vs. 4096 mg/L). LipoBiEDT-TOB was significantly less toxic when compared to the free BiEDT, as evaluated by the MTT and LDH assay. The LipoBiEDT-TOB formulation suppressed bacterial adhesion (B. cenocepacia M13642R) to A549 cells. These data suggest that the novel LipoBiEDT-TOB drug delivery system could be utilized as a new strategy to enhance the efficacy of existing antibiotics against resistant organisms that commonly affect individuals with chronic lung infections.

Cysteamine or beta-mercaptoethanol added to a defined maturation medium improves blastocyst formation of porcine oocytes after intracytoplasmic sperm injection.

The present study was carried out to investigate the effect of adding 100 microM cysteamine (Cys) or 100 microM beta-mercaptoethanol (beta-ME) to a defined maturation medium on in vitro maturation (IVM), and fertilization and developmental competence of in vitro matured porcine oocytes following intracytoplasmic sperm injection (ICSI). The two control media for IVM culture were modified TCM199 containing 10% (v/v) porcine follicular fluid (pFF) or 0.05% (w/v) polyvinyl alcohol (PVA), and Cys or beta-ME was supplemented to the PVA-control medium. There was no significant difference in the proportions of in vitro matured oocytes among the four treatment groups (94.5-98.4%). The percentages of pronuclear formation (51.0-64.2%) after ICSI were also not significantly different among the four groups. The cleavage rate (72.8%) in the oocytes treated with Cys showed no significant difference compared with those of the two control media containing pFF (72.2%) or PVA (61.5%), but was higher (P<0.05) than that in the oocytes treated with beta-ME (56.3%). However, the rates of blastocyst formation of Cys (36.7%), beta-ME (27.1%) and pFF (31.4%) were higher (P<0.05) than that using the control medium containing PVA (15.6%). The mean cell number of blastocysts ranged from 42 to 52 among the four groups, without significant differences. In conclusion, the addition of Cys or beta-ME to a defined maturation medium enhanced blastocyst formation after ICSI, to a level similar to that achieved by adding pFF.

Effects of beta-mercaptoethanol and cycloheximide on survival and DNA damage of bovine embryos stored at 4 degrees C for 72 h.

The objectives of this study were to determine the effects of cycloheximide (CHX) and beta-mercaptoethanol (beta-ME) during storage of in vitro-produced (IVP) bovine blastocysts for 72 h at 4 degrees C on their survival, hatching capacity and DNA damage. In Experiment 1, when blastocysts were stored in a medium supplemented with 25, 50 or 100 microg/mL of CHX, or 25, 50 or 100 microM of beta-ME, the blastocysts stored with 25 microg/mL of CHX had a significantly higher survival rate than that of the blastocysts stored without CHX (79.5% versus 54.2%). In contrast, beta-ME had no apparent effects on the survival and hatching capacity of stored embryos. In Experiment 2, to investigate synergistic effects of CHX and beta-ME during storage of blastocysts on their developmental parameters and DNA damage, they were stored in the medium with CHX (25 microg/mL) and beta-ME (50 microM). The combination of CHX and beta-ME had no significant effects on the survival of blastocysts. The proportion (6.8%) of DNA-fragmented cells in the blastocysts stored with CHX was similar to that (5.4%) in the non-stored blastocysts (positive control) and significantly lower than that (9.7%) in the blastocysts stored without CHX and beta-ME (negative control). However, there were no significant differences among the proportions of dead cells of blastocysts in the storage groups. Therefore, the supplementation of CHX in the storage medium had a beneficial effect on the proportions of survival and DNA-fragmented cells in the stored embryos, whereas the beta-ME alone or in combination with CHX had no positive effects on either of these proportions.

Neuropeptide Y bioavailability is suppressed in the hindlimb of female Sprague-Dawley rats.

We recently reported that male, but not female, rats exhibit basal endogenous neuropeptide Y Y(1)-receptor modulation of hindlimb vasculature. The lack of baseline endo-genous Y(1)-receptor control in females was evident despite the expression of Y(1)-receptors and neuropeptide Y in hindlimb skeletal muscle tissue. The following study addressed the hypothesis that neuropeptide Y bioavailability is blunted in female rats under baseline conditions. It was further hypothesized that enhanced prejunctional autoinhibitory neuropeptide Y Y(2)-receptor expression and/or proteolytic processing of released neuropeptide Y may persist in female rats. Using western blot analysis, it was observed that females had greater overall neuropeptide Y Y(2)-receptor expression in skeletal muscle compared to males (P < 0.05). To address the prevalence/impact of baseline endogenous Y(2)-receptor activation on neuropeptide Y release in hindlimb vasculature, an arterial infusion of BIIE0246 (specific non-peptide Y(2)-receptor antagonist; 170 microg kg(-1)) was carried out on female and male rats. Y(2)-receptor blockade resulted in a decrease in hindlimb vascular conductance in females and males (P < 0.05). However, the BIIE0246-induced decrease in vascular conductance was Y(1)-receptor dependent in females, but not males (P < 0.05). In addition, compared to baseline, BIIE0246 infusion resulted in increased plasma neuropeptide Y concentration in females (P < 0.05), while there was no observable change in males. In a final experiment, systemic inhibition of proteolytic enzymes dipeptidylpeptidase IV (via 500 nM diprotin A) and aminopeptidase P (via 180 nM 2-mercaptoethanol) elicited a Y(1)-receptor-dependent decrease in hindlimb vascular conductance in females (P < 0.05). It was concluded that our previously reported lack of basal endogenous Y(1)-receptor activation in female hindlimb vasculature was (at least partially) due to prejunctional Y(2)-receptor autoinhibition and proteolytic processing of neuropeptide Y.

Implications of beta-mercaptoethanol in relation to folate stability and to determination of folate degradation kinetics during processing: a case study on [6S]-5-methyltetrahydrofolic acid.

The effect of beta-mercaptoethanol (0-2%) addition to thermally and/or pressure-treated samples on [6S]-5-methyltetrahydrofolate was studied. Degradation of [6S]-5-methyltetrahydrofolate during both thermal and pressure treatments was mainly caused by oxidation, and the oxidized folates could be partly/completely reduced by beta-mercaptoethanol. The addition of beta-mercaptoethanol (2%) to the thermally and pressure-treated samples overestimated the "actual" stability of [6S]-5-methyltetrahydrofolate and misled the obtained kinetic information.

Addition of beta-mercaptoethanol or Trolox at the morula/blastocyst stage improves the quality of bovine blastocysts and prevents induction of apoptosis and degeneration by prooxidant agents.

This study was conducted to evaluate the effect of beta-mercaptoethanol (a stimulator of glutathione synthesis) and Trolox (an hydrosoluble analogue of Vitamin E) on bovine embryos cultured from the morula stage (Day 5 post-insemination; pi) under oxidative stress conditions. Culture of embryos with increased doses of Trolox showed a dose-dependent embryotoxicity on Day 8 pi. The use of 400 microM Trolox as well as beta-mercaptoethanol at 100 microM prevented at least partly (P < 0.05) the prooxidant-induced blastocyst degeneration on Day 8. Hatching rates of surviving blastocysts were significantly increased by both antioxidants and beta-mercaptoethanol alone improved their mean cell numbers, which was significant in the ICM (P < 0.05). Analysis of their effect on Day 7 pi showed that both the antioxidants significantly reduced the prooxidant-induced apoptosis and beta-mercaptoethanol diminished the physiological level of apoptosis as well as it stimulated the glutathione synthesis (P < 0.05). In addition, a comparison between in vitro- and in vivo-produced embryos showed that the levels of apoptosis were similar at the same age post-insemination (morulae and blastocysts) but increased steadily with the embryonic age in in vitro ones. In conclusion, beta-mercaptoethanol and Trolox added separately from the morula stage protected embryos against oxidative stress and improved the quality of the resulting blastocysts.

Augmentation by 2-mercaptoethanol of in vitro anti-TNP antibody production induced by butyrate plus IL-2 in murine splenic B cells.

We previously reported that anti-trinitrophenyl (TNP) antibody production in murine splenic B cells stimulated with TNP-lipopolysaccharide in vitro was promoted by sodium butyrate (NaBu) in an IL-2-dependent manner. In the present study, we found that the effect of NaBu plus IL-2 was markedly augmented by 2-mercaptoethanol (2-ME), which showed a slight or null effect on the response of untreated, IL-2-treated or NaBu-treated B cells, as assessed by both anti-TNP plaque-forming cell assay and anti-TNP IgM ELISA. Other thiol compounds such as dithiothreitol, cysteamine and reduced glutathione (GSH) also had this activity. 2-ME enhanced the anti-TNP antibody production induced by other short-chain fatty acids with three to five carbon atoms plus IL-2. The proliferation of B cells was significantly inhibited by NaBu or NaBu plus IL-2, and the proliferation was completely restored by the simultaneous addition of 2-ME. These results demonstrate that 2-ME markedly enhanced anti-TNP antibody production in murine B cells induced by NaBu plus IL-2 and suggest that the effect of 2-ME is at least partly due to its blocking activity of the growth-inhibitory action of NaBu.

A mesoporous silica nanosphere-based carrier system with chemically removable CdS nanoparticle caps for stimuli-responsive controlled release of neurotransmitters and drug molecules.

An MCM-41 type mesoporous silica nanosphere-based (MSN) controlled-release delivery system has been synthesized and characterized using surface-derivatized cadmium sulfide (CdS) nanocrystals as chemically removable caps to encapsulate several pharmaceutical drug molecules and neurotransmitters inside the organically functionalized MSN mesoporous framework. We studied the stimuli-responsive release profiles of vancomycin- and adenosine triphosphate (ATP)-loaded MSN delivery systems by using disulfide bond-reducing molecules, such as dithiothreitol (DTT) and mercaptoethanol (ME), as release triggers. The biocompatibility and delivery efficiency of the MSN system with neuroglial cells (astrocytes) in vitro were demonstrated. In contrast to many current delivery systems, the molecules of interest were encapsulated inside the porous framework of the MSN not by adsorption or sol-gel types of entrapment but by capping the openings of the mesoporous channels with size-defined CdS nanoparticles to physically block the drugs/neurotransmitters of certain sizes from leaching out. We envision that this new MSN system could play a significant role in developing new generations of site-selective, controlled-release delivery nanodevices.