Effect of glycine on the induction of orotic aciduria and urinary bladder tumorigenesis in the rat

Biological differences underlying sex and gender disparities in bladder cancer: current synopsis and future directions

Sex and gender disparities in bladder cancer have long been a subject of interest to the cancer research community, wherein men have a 4 times higher incidence rate than women, and female patients often present with higher-grade disease and experience worse outcomes. Despite the known differences in disease incidence and clinical outcomes between male and female bladder cancer patients, clinical management remains the same. In this review, we critically analyze studies that report on the biological differences between men and women and evaluate how these differences contribute to sex and gender disparities in bladder cancer. Distinct characteristics of the male and female immune systems, differences in circulating hormone levels and hormone receptor expression, and different genetic and epigenetic alterations are major biological factors that all likely contribute to disparate incidence rates and outcomes for male and female bladder cancer patients. Future preclinical and clinical studies in this area should employ experimental approaches that account for and consider sex and gender disparities in bladder cancer, thereby facilitating the development of precision medicine for the effective treatment of bladder cancer in all patients.

Gold nanoparticles capped with L-glycine, L-cystine, and L-tyrosine: toxicity profiling and antioxidant potential

Biomolecules-based surface modifications of nanomaterials may yield effective and biocompatible nanoconjugates. This study was designed to evaluate gold nanoconjugates (AuNCs) for their altered antioxidant potential. Gold nanoparticles (AuNPs) and their conjugates gave SPR peaks in the ranges of 512-525 nm, with red or blueshift for different conjugates. Cys-AuNCs demonstrated enhanced (p < 0.05) and Gly-AuNCs (p > 0.05) displayed reduced DPPH activity. Gly-AuNCs and Tyr-AuNCs displayed enhanced ferric-reducing power and hydrogen peroxide scavenging activity, respectively. Cadmium-intoxicated mice were exposed to gold nanomaterials, and the level of various endogenous parameters, i.e., CAT, GST, SOD, GSH, and MTs, was evaluated. GSH and MTs in liver tissues of the cadmium-exposed group (G2) were elevated (p < 0.05), while other groups showed nonsignificance deviations than the control group. It is concluded that these nanoconjugates might provide effective nanomaterials for biomedical applications. However, more detailed studies for their safety profiling are needed before their practical applications.

Histopathological evaluation of amino acid capped silver nanoconjugates in albino mice

Various molecules may modify the surface chemistry of commonly used nanomaterials (NMs), resulting in the synthesis of novel and safer NMs. The current study was delineated to evaluate the in vivo toxicity profiling of the silver nanoconjugates (AgNCs) conjugated with different amino acids. The L-glycine capped-AgNCs exhibited toxicity and caused tissue damage, while L-cystine- and L-tyrosine-capped AgNCs showed protective effects against cadmium-induced toxicity. L-cystine-capped AgNCs performed well as compared to other amino-acid AgNCs. The level of serum creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase and blood urea increased (p < 0.05) in G2, G3 and G5 in comparison to G1 (control group), while an increase in bilirubin for G2 was statistically non-significant (p > 0.05). The ALT and AST elevated (p < 0.05) in G4; however, other serological parameters in G4 and G6 did not show any noticeable change in their values. Histological analysis showed disturbed and deformed cellular structures in liver and kidney tissues of G2, G3 and G5. However, G4 and G6 samples demonstrated minute changes in comparison to G1. It is concluded that L-cystine- and L-tyrosine-capped AgNCs exhibited protective effects and should be tested further for developing safer nanoconjugates for biomedical uses.

Stable Gastric Pentadecapeptide BPC 157 Heals Established Vesicovaginal Fistula and Counteracts Stone Formation in Rats

With the stable gastric pentadecapeptide BPC 157 therapy known to heal various both external and internal rat fistulas, we attempt to approach vesicovaginal fistula, continuous urine leaking through vagina, bladder stones, and a possible therapy solution among rats with well-formed 2 week-fistulas (vaginal/vesical 4 mm large defects) started with delayed therapy. Subsequent control fistula course (the subsequent 1, 2, 4, and 6 weeks) since beginning revealed the failed healing, fistula leaking, adhesions, urinary leaking through vagina, failed epithelization, collagenization, granulation tissue and neovascularization, increased inflammation, and necrosis. Thereby, the later intervals revealed the persistent inability to sustain even minimal volume, vesical, and vaginal defects and stone formation at the end of the experiment (fistula-time day 56). BPC 157 therapy (10 µg/kg, 10 ng/kg, intraperitoneally once time daily or perorally in drinking water until sacrifice) was initiated with a considerable delay (at 2 weeks after fistula formation). Already within 1 week therapy, all BPC 157 regimens stopped urinary leaking through vagina, reversed the otherwise resistant poor healing course to the increased epithelization, collagenization, granulation tissue and neovascularization, decreased inflammation, and decreased necrosis. Thereby, at later intervals, all BPC 157 rats exhibited a five times larger volume that can be sustained before leaking as in healthy, vesical, and vaginal defects completely closed and no stone formation. Thus, macro/microscopic and functional recovery, and counteracted stone formation. Concluding, BPC 157 therapy’s beneficial effects resulted in healing and no stone formation, with µg- and ng-regimens, either given daily perorally in drinking water or intraperitoneally.

The nature of human hazards associated with excessive intake of amino acids

In recent years there has been a large increase in the consumption of individual amino acids as dietary supplements. This has resulted not only from the use of certain amino acids as flavoring agents, but other amino acids are taken for perceived health benefit, for enhancement of physical performance, as well as for psychological effects. Two reviews of the scientific literature exist that mainly deal with effects in animals, and three major reports consider the safety of amino acids for human consumption. This article is a brief summary of the available evidence regarding the safety of individual amino acids when taken in excess relative to the amounts absorbed from dietary protein.

The effects of various inhibitors on the regulation of orotic acid excretion in sparse-fur mutant mice (spf/Y) deficient in ornithine transcarbamylase

Experiments were conducted to determine whether the excessive orotic aciduria, induced in sparse-fur male mice (spf/Y) deficient in ornithine transcarbamylase (OTC), may be regulated by some inhibitors, such as acivicin (0.014 mmol/100 g body weight, i.p.), N-(phosphonoacetyl)-L-aspartate (PALA, 2.5 mg/100 g body weight, i.p.), adenine (3 g/kg diet) and cycloheximide (0.35 mmol/kg body weight, i.p.). We also administered ornithine (1 mmol/100 g body weight, i.p.), a substrate of the urea cycle, to alleviate the metabolic deficiency of arginine in spf/Y mice which may also be responsible for excessive orotic aciduria. The orotic aciduria remained insensitive to acivicin, indicating mitochondria as the source of carbamyl phosphate. However, orotate excretion was significantly decreased by PALA (P < 0.01), due to its effect on the aspartate transcarbamylase activity. The ingestion of adenine resulted in an increase (P < 0.05) of urinary orotate, suggesting the blockage of the utilization of orotate for nucleotide biosynthesis. Ornithine administration led to a reduction (P < 0.01) of the excretion of orotate induced by the OTC deficiency in these mice, indicating that one of the regulatory steps in its synthesis may be the availability of ornithine. There were no changes in urinary orotate excretion in spf/Y mice when treated with cycloheximide. On the other hand, pretreatment with cycloheximide in an artificial model of OTC deficiency (Swiss-ICR normal mice on an arginine-deficient diet treated thereafter with norvaline, an inhibitor of OTC), caused a significant decrease in urinary orotate. These results suggest that spf/Y mice are unique in that the increased synthesis of orotate is not sensitive to cycloheximide. Perhaps this may reflect an adaptive phenomenon developed by the mutant mice to handle excess mitochondrial carbamyl phosphate and orotic acid.

A data-derived safety (uncertainty) factor for the intense sweetener, saccharin

An increased incidence of bladder cancer is found when male rats are fed high dietary concentrations of sodium saccharin (3% or more) from birth. This toxicity has been used as the basis for the development of a data-derived safety factor. Such an effect would attract an extra factor (10-fold) for nature of toxicity and in the absence of other data would result in a high overall safety factor. However the extensive mechanistic database on sodium saccharin allows an assessment of the potential relevance of the effect for humans. In addition the effect is only seen under specific conditions in rats, i.e. largely with the sodium salt and with a commercial rat diet. The effect is not related to the concentration of saccharin in the rat urine or bladder so that toxicokinetic considerations are simplified. The extensive animal database allows the determination of data-derived factors for inter-species differences in both toxicokinetics and toxicodynamics. Based on this analysis an overall safety factor of 50 (which includes the factor of 10 for severity of effect) would appear appropriate at the present time. This factor, and the ADI which would result from its application, are consistent with the absence of an association between the consumption of artificial sweeteners and bladder cancer in humans.

Endogenous mutagens derived from amino acids

L-Cysteine, glutathione and the therapeutically used L-cysteine precursor, N-acetyl-L-cysteine, induced strong mutagenic effects in Salmonella typhimurium (reversion of the his- strains TA97, TA92 and TA104), when tested in the presence of subcellular kidney preparations. The tyrosine metabolites, levodopa (an ortho-hydroquinone) and homogentisic acid (a para-hydroquinone) reverted various his- strains as well. This mutagenicity did not require the presence of mammalian enzymes, and was relatively weak. The induction of gene mutations was also studied in mammalian cells (V79 Chinese hamster cells), using acquisition of resistance toward 6-thioguanine as the marker. L-Cysteine and N-acetyl-L-cysteine were found to be inactive, levodopa was weakly mutagenic, and homogentisic acid was strongly mutagenic (enhancing the mutation frequency 135-fold above background at an exposure concentration of 50 microM). This finding is striking as the urinary concentration of homogentisic acid is about 1000 times higher in patients with a genetic defect in homogentisic acid 1,2-dioxygenase (alkaptonuria). Genotoxic and carcinogenic effects of other amino acids and metabolites, reported in the literature, are discussed as well.