An interesting concept that has emerged from initial findings is that regeneration and fibrosis are competing events in the vertebrate heart. That is, if there is a capacity for injury-stimulated cardiomyocyte hyperplasia beyond a certain threshold, regenerative mechanisms will overcome scarring. Results consistent with this idea came from experiments with zebrafish possessing a ts mutation in the cell-cycle checkpoint kinase Mps1 (Poss et al., 2002b). As mentioned earlier, mps1 mutants were initially identified based on their defects in caudal fin regeneration. Serendipitously, mps1 mutants also showed defects in cardiac regeneration at a temperature restrictive for the mutation (Poss et al., 2002b). Instead of regenerating muscle in response to ventricular resection injury, mps1 mutants repaired wounds by forming large, collagen-rich scars. Inhibition of Fgf signaling also stunts cardiac regeneration and causes scarring (Lepilina et al., 2006). These results indicate that even vertebrates with high cardiac regenerative capacity have a default scarring mechanism; normally, regeneration somehow restricts this pathway (Fig. 8). The implication is exciting; perhaps by stimulating regeneration in a poorly-regenerative system like the mammalian heart, scarring events characteristic of myocardial infarction would be restricted by new muscle formation. Similarly, deterring cardiac scarring mechanisms would perhaps favor regeneration in mammals.
Nolen, W. A., van de Putte, J. J., Dijken, W. A., Kamp, J. S., Blansjaar, B. A., Kramer, H. J., and Haffmans, J. Treatment strategy in depression. II. MAO inhibitors in depression resistant to cyclic antidepressants: two controlled crossover studies with tranylcypromine versus L-5-hydroxytryptophan and nomifensine. Acta Psychiatr.Scand 1988;78(6):676-683. View abstract.
Cells were incubated for 48 hours with the indicated times with 200 μM H2O2 (A) and the indicated concentrations of H2O2 (B) for 48 hours. The mRNA and protein expressions were examined by RT-PCR and Western blotting, respectively. Data were representative of three independent experiments. The bar graph shows the fold increase in protein or mRNA expression compared with control cells. * Statistically significant differences compared with the control, p<0.05.
Melanotan II first captured the public's imagination when the mainstream media briefly touted it as a Viagra-like panacea for middle-aged men. Norman Levine, a dermatologist who led the team that developed the drug, had first conducted experiments in which he darkened the pigments of frogs by injecting them with a hormone called Alpha MSH. After Melanotan II was modified for human use and put through clinical trials, Levine reported that "one very astute observer who took this drug told us that he was developing spontaneous erections."
When we asked a group of readers to test out 5-HTP to lose weight, they ate unlimited portions of healthy food and still shed up to five pounds in a week. We also talked to women who’d been using 5-HTP long term. Heather Miars started taking 5-HTP for her mood at Dr. Bhatia’s urging. “I was finally able to go off prescription antidepressants and lose 15 pounds!” recalls the 45-year-old mom. Meanwhile, Audra Holmes tried 5-HTP after developing “mood swings so wild, I was giving people whiplash,” she jokes. On 5-HTP, she says: “I didn’t have the highs and lows. I could suddenly get through the day without naps or comfort food!” She shed 50 pounds in 16 weeks. Wish you could have the same kind of success with an easy way to lose weight? As Dr. Oz put it: “5-HTP may be your pre-meal must-have!”
Drug interaction: Impact on effects of alcohol and other drugs: According to several studies in animals, oxytocin inhibits the development of tolerance to various addictive drugs (opiates, cocaine, alcohol), and reduces withdrawal symptoms. MDMA (ecstasy) may increase feelings of love, empathy, and connection to others by stimulating oxytocin activity primarily via activation of serotonin 5-HT1A receptors, if initial studies in animals apply to humans. The anxiolytic Buspar (buspirone) may produce some of its effects via 5-HT1A receptor-induced oxytocin stimulation as well.
To evaluate the indirect effect of Tβ4 peptide on RANKL-induced osteoclastogenesis, mouse BMMs were incubated with RANKL and CM, prepared from HPDLCs treated with H2O2 and different concentrations of Tβ4, and allowed to differentiate into osteoclasts. As shown in Fig 6, Tβ4 peptide dose-dependently decreased the number of osteoclasts and TRAP activity. To determine whether the reduction in osteoclast generation by Tβ4 could be due to effects of Tβ4 peptide on viability of the BMMs, a cytotoxicity assay was performed. The viability of BMMs was not significantly affected by Tβ4 peptide (data not shown).
The matters under subsection 52E (1) of the Therapeutic Goods Act 1989 considered relevant by the delegate included: (a) the risks and benefits of the use of the substance; (b) the purposes for which a substance is to be used and the extent of use of a substance; (c) the toxicity of the substance; (d) the dosage, formulation, labelling, packaging and presentation of a substance; (e) the potential for abuse of a substance; and (f) any other matters that the Secretary considers necessary to protect public health.
Oxytocin secreted from the pituitary gland cannot re-enter the brain because of the blood-brain barrier. Instead, the behavioral effects of oxytocin are thought to reflect release from centrally projecting oxytocin neurons, different from those that project to the pituitary gland. Oxytocin receptors are expressed by neurons in many parts of the brain and spinal cord, including the amygdala, ventromedial hypothalamus, septum and brainstem.
Work with cell cultures and experiments with animals have shown that administration of thymosin β4 can promote migration of cells, formation of blood vessels, maturation of stem cells, survival of various cell types and lowering of the production of pro-inflammatory cytokines. These multiple properties have provided the impetus for a worldwide series of on-going clinical trials of potential effectiveness of thymosin β4 in promoting repair of wounds in skin, cornea and heart.
TB-500 is a synthetic version of the naturally occurring peptide present in virtually all human and animal cells, Thymosin Beta-4. This potent peptide is a member of a ubiquitous family of 16 related molecules with a high conservation of sequence and localization in most tissues and circulating cells in the body. TB-500 not only binds to actin, but also blocks actin polymerization and is the actin-sequestering molecule in eukaryotic cells.
Exogenous Tβ4 can function like a hormone on cells in terms of its ability to modulate their biological behavior. Since one of the primary roles of Tβ4 in cells is the sequestration of actin monomers, and the protein is not secreted, previously indicated that it was unlikely that Tβ4 could have a hormonal function . However, other studies have shown that the intracellular level of Tβ4 or its mRNA can be significantly and rapidly altered by external stimuli and that change in the level of Tβ4 often are correlated with cell differentiation [18, 43]. In the present study, exogenous Tβ4 peptide activate intracellular Tβ4, which results suggested that exogenous Tβ4 spontaneously enter the cytoplasm through rapid internalization, and acts their functions same as endogenous one [8, 18].
Autism. A 1998 study found significantly lower levels of oxytocin in blood plasma of autistic children.7 A 2003 study found a decrease in autism spectrum repetitive behaviors when oxytocin was administered intravenously.8 A 2007 study reported that oxytocin helped autistic adults retain the ability to evaluate the emotional significance of speech intonation.9
Indeed, the findings that progenitor cells of some form exist both in the regenerative zebrafish heart, and in the hearts of less-regenerative mammals supports this idea. Zebrafish have ostensibly found some method to optimize the activity of progenitor cells, perhaps either by maintaining more cells, or by harboring a more cultivating environment for regeneration. Also, both mammalian and nonmammalian hearts contain an epicardial cell layer, yet zebrafish have found some way to activate the epicardium after injury, a process linked with essential neovascularization of regenerating muscle (Lepilina et al., 2006. This result points to the adult mammalian epicardium as a potential cellular source to assist myocardial regeneration or survival. Indeed, mammalian myocardial infarcts typically show poor or insufficient neovascularization, a response that many are trying to improve experimentally. Recent findings have indicated that the G-actin sequestering protein, Thymosin-ß4, may influence the mammalian epicardium. Treatment of adult cardiac explants with Thymosin-ß4 induced the migration of fibroblasts, endothelial and smooth muscle cells as assessed by gene expression and cellular morphology (Smart et al., 2007). In addition, in vivo Thymosin-ß4 treatment could partially restore cardiac survival and function following coronary ligation (Bock-Marquette et al., 2004). Notably, Thymosin-ß4 expression is induced in the injured zebrafish heart, suggesting that fish naturally release this epicardial stimulant on injury (Lien et al., 2006).
“This is a very ancient molecule,” says Sue Carter, a neuroscientist at Indiana University in Bloomington, whose lab pioneered many of the early studies of oxytocin in voles. “It has been used and reused for many purposes across the evolution of modern animals, and almost everybody who's tried to look at an effect of oxytocin on anything like social behaviour has found something.”
5-HTP is sometimes taken by people coming down from MDMA to relieve post-MDMA dysphoria. As 5-HTP is a necessary precursor for the brain to produce more serotonin, and MDMA use depletes a person's natural serotonin levels, it is believed that taking 5-HTP after consuming MDMA will speed up serotonin production. DanceSafe claims that the anecdotal evidence is widespread and that the theory is physiologically reasonable. Backing up this approach is research conducted by Wang, et al. in 2007, which observed that MDMA-induced depletions of 5-HT (serotonin) were restored in rats after administration 5-HTP, and suggested that this approach might be clinically useful in abstinent MDMA users.