Effect of tert-butyl acetate and ethyl butyrate on the dissolution of gallbladder cholesterol stones / 中华肝胆外科杂志

Objective:To compare the effect and biotoxicity of tert-butyl acetate (TBA) and ethyl butyrate (EB) on stone dissolution in vitro.Methods:Ten gallstone samples from patients with multiple gallbladder stones were selected and the cholesterol content was analyzed by HPLC. Stone dissolution tests of TBA and EB were performed on cholesterol gallstone in vitro, and the weight of stone at each time point was recorded, meanwhile, methyl tert-butyl ether (MTBE) was used as the control. The inhibitory effects of MTBE, TBA and EB on proliferation of human normal liver cell line LO2 were analyzed by cell proliferation inhibition assay. Flow cytometry was used to analyze the effects of MTBE, TBA and EB on the early and late apoptosis of LO2 cells, and the changes of reactive oxygen species level in LO2 cells were also analyzed.Results:Of the 10 gallbladder gallstones, 6 were cholesterol gallstones and 4 were non-cholesterol gallstones. Stone dissolution experiment showed that the remaining stones of MTBE, TBA and EB groups were (47.83±3.84)%, (58.12±4.53)% and (75.75±4.61)% 30 minutes later. The remaining stones were (18.38±6.47)%, (33.82±6.22)% and (56.38±3.91)% 90 minutes later. MTBE had the best stone dissolution effect in vitro, the stone dissolution effect of TBA was slightly weaker than MTBE, and the stone dissolution effect of EB was relatively weak in all ( P<0.05). The cell proliferation inhibition experiment showed that the cell viability of the control group, MTBE group and TBA group were (100.00±4.46)%, (96.79±4.32)% and (93.72±3.51)%, respectively, and there were no significant differences among the three groups ( P>0.05). However, the cell viability of EB group (87.57±5.29)% was lower than the above three groups, and the differences were statistically significant ( P<0.001). The early apoptosis and late apoptosis of the control group were (1.67±0.15)% and (1.27±0.06)%, respectively. EB induced early apoptosis (15.90±0.53)% ( P<0.001) and late apoptosis (5.13±0.76)% ( P<0.05). However, MTBE and TBA had no significant effect on cell apoptosis ( P>0.05). Compared with control group, MTBE, TBA and EB all significantly inhibited the level of reactive oxygen species ( P<0.05), and the inhibitory effect of EB was the most obvious. Conclusions:TBA has good stone dissolution effect and biosafety for gallbladder cholesterol stones in vitro, while EB has relatively poor performance. TBA is a potential drug for gallstone dissolution.

Biomedical applications of L-alanine produced by Pediococcus acidilactici BD16 (alaD+).

L-alanine possesses extensive physiological functionality and tremendous pharmacological significance, therefore could be considered as potential ingredient for food, pharmaceutical, and personal care products. However, therapeutic properties of L-alanine still need to be addressed in detail to further strengthen its utilization as a viable ingredient for developing natural therapeutics with minimum side effects. Thus, the present study was aimed to explore the anticipated therapeutic potential of L-alanine, produced microbially using a lactic acid bacterial strain Pediococcus acidilactici BD16 (alaD+) expressing L-alanine dehydrogenase enzyme. The anticipated therapeutic potential of L-alanine was assessed in terms of anti-proliferative, anti-bacterial, and anti-urolithiatic properties. Anti-bacterial assays revealed that L-alanine successfully inhibited growth and in vitro proliferation of important human pathogens including Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, Streptococcus mutans, and Vibrio cholerae in a concentration-dependent manner. Current investigation has also revealed its significant anti-proliferative potential against human lung adenocarcinoma (A549; IC50 7.32 µM) and mammary gland adenocarcinoma (MCF-7; IC50 8.81 µM) cells. The anti-urolithiatic potential of L-alanine was augmented over three different phases, viz., nucleation inhibition, aggregation inhibition, and oxalate depletion. Further, an in vitro cell culture-based kidney stone dissolution model using HEK293-T cells was also established to further strengthen its anti-urolithiatic potential. This is probably the first in vitro cell culture-based model which experimentally validates the immense therapeutic efficacy of L-alanine in treating urolithiasis disease. KEY POINTS: • Assessment of therapeutic potential of L-alanine produced by LAB. • L-alanine exhibited significant anti-proliferative and anti-bacterial activities. • L-alanine as potential anti-urolithiatic agent.

[Dissolution of uric acid stones in the ureter].

INTRODUCTION: Uric acid stones (UA), consisting of uric acid/uric acid dihydrate, occur in 6.1-15.1% of all cases of urolithiasis in industrialized countries. At the same time, the frequency of these stones is directly dependent on age. Thus, the incidence of UA reaches 40% in men over 80 years of age and 27.3% in women over 90 years of age. UA are the only stones that are amenable to dissolution therapy with the use of citrate salts that alkalinize urine pH. A number of authors and European Association of Urology guidelines consider stone dissolution as a first-line therapy in the treatment of patients with UA, both as monotherapy and in combination with surgical procedures. MATERIALS AND METHODS: The results of conservative treatment of 86 patients aged 28 to 78 years with radiolucent ureteral stones ranging in size from 3 to 25 mm and a density of 133 to 728 HU, who underwent 89 courses of stone dissolution therapy from 2011 to 2018, are presented in the article. They had no obstruction or were prestented. There were 52 men (n=55 courses) and 34 women (n=34 courses). RESULTS: In 78 out of 89 clinical cases (87.6%), stone-free status was obtained within 14 to 181 days. Most often the duration of therapy was 30 days. In 11 (12.4%) cases the treatment was considered ineffective. However, only in 4 (4.5%) patients the stone size did not change, while in 7 (7.9%) cases it decreased. The results of the study suggest the high efficiency of citrate therapy in patients with ureteral stones in case of unobstructed urine outflow (including those with stents), which is comparable to surgical treatment.

Medical and Interventional Management of Upper Urinary Tract Uroliths.

Nephroliths are often clinically silent. When non-obstructive and of an amenable stone type, dissolution should be attempted. When problematic, nephrolithotomy can be considered. Depending on stone type, size, and species, extracorporeal shockwave lithotripsy or endoscopic nephrolithotomy are preferred techniques. Obstructive ureterolithiasis should be addressed immediately to preserve kidney function. Because of decreased morbidity and mortality and versatility for all causes, interventional techniques for kidney decompression are preferred by the authors. Proper training and expertise in these interventional techniques should be acquired before performing them on clinical patients for the best possible outcomes.