Induced precipitation of calcium-oxalate crystals and its prevention in laboratory animals

The association of dietary intake of riboflavin and thiamine with kidney stone: a cross-sectional survey of NHANES 2007-2018

BACKGROUND

Kidney stone disease (KSD) is a common condition that affects 10% population in the United States (US). The relationship between thiamine and riboflavin intake and KSD has not been well-studied. We aimed to investigate the prevalence of KSD and the association between dietary thiamine and riboflavin intake with KSD in the US population.

METHODS

This large-scale, cross-sectional study included subjects from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. KSD and dietary intake were collected from questionnaires and 24-hour recall interviews. Logistic regression and sensitivity analyses were performed to investigate the association.

RESULTS

This study included 26,786 adult participants with a mean age of 50.12 ± 17.61 years old. The prevalence of KSD was 9.62%. After adjusting for all potential covariates, we found that higher riboflavin intake was negatively related to KSD compared with dietary intake of riboflavin < 2 mg/day in the fully-adjusted model (OR = 0.541, 95% CI = 0.368 to 0.795, P = 0.002). After stratifying by gender and age, we found that the impact of riboflavin on KSD still existed in all age subgroups (P < 0.05) but only in males (P = 0.001). No such associations were found between dietary intake of thiamine and KSD in any of the subgroups.

CONCLUSIONS

Our study suggested that a high intake of riboflavin is independently inversely associated with kidney stones, especially in male population. No association was found between dietary intake of thiamine and KSD. Further studies are needed to confirm our results and explore the causal relationships.

Effects of dietary antioxidant supplementation before and after oral acetaminophen challenge in cats

OBJECTIVE

To determine effects of lipoic acid, vitamin E, and cysteine before and after oxidant challenge in cats.

ANIMALS

24 sexually intact adult cats.

PROCEDURE

Cats were allocated into 4 equal groups. For 25 weeks, group A was fed a control dry diet and groups B, C, and D received this diet supplemented with vitamin E (2200 U/kg [dry matter basis {DMB}]) plus cysteine (9.5 g/kg [DMB]), lipoate (150 mg/kg [DMB]), or all 3 antioxidants together, respectively. Weights were measured every 3 days and venous blood obtained every 5 weeks for CBC; serum biochemical analyses; lymphocyte blastogenesis; thiobarbituric acid reactive substances concentration; and concentrations of plasma protein carbonyl, 8-OH d-guanosine, blood glutathione, plasma amino acid, lipoate, and dihydrolipoate. At 15 weeks, all cats received acetaminophen (9 mg/kg, PO, once), clinical effects were observed, and methemoglobin concentrations were measured.

RESULTS

Lymphocyte blastogenesis increased transiently in group C and D cats. After acetaminophen administration, all groups had transient increases in methemoglobin within 4 hours and mild, brief facial edema; group C had decreased glutathione concentration and increased 8-OH d-guanosine concentration versus controls; and protein carbonyl concentration increased least for group B. Plasma lipoate and dihydrolipoate concentrations peaked by week 10 for groups C and D. Conclusions and Clinical Relevance-Lipoate, vitamin E, and cysteine did not have synergistic effects. Lipoate supplementation (150 mg/kg [DMB]) did not act as an antioxidant but appeared to enhance oxidant effects of acetaminophen. Vitamin E plus cysteine had protective effects.

The inhibitory effects of lipoic compounds on mammalian pyruvate dehydrogenase complex and its catalytic components

To examine the stereospecific effects of lipoic compounds on pyruvate metabolism, the effects of R-lipoic acid (R-LA), S-lipoic acid (S-LA) and 1,2-diselenolane-3-pentanoic acid (Se-LA) on the activities of the mammalian pyruvate dehydrogenase complex (PDC) and its catalytic components were investigated. Both S-LA and R-LA markedly inhibited PDC activity; whereas Se-LA displayed inhibition only at higher concentrations. Examination of the effects on the individual catalytic components indicated that Se-LA inhibited the pyruvate dehydrogenase component; whereas R-LA and S-LA inhibited the dihydrolipoamide acetyltransferase component. The three lipoic compounds lowered dihydrolipoamide dehydrogrenase (E3) activity in the forward reaction by about 30 to 45%. The kinetic data of E3 showed that both R-LA and Se-LA are used as substrates by E3 for the reverse reaction. Decarboxylation of [1-14C]pyruvate via PDC by cultured HepG2 cells was not affected by R-LA, but moderately decreased with S-LA and Se-LA. These findings indicate that (i) purified PDC and its catalytic components are affected by lipoic compounds based on their stereoselectivity; and (ii) the oxidation of pyruvate by intact HepG2 cells is not inhibited by R-LA. The later finding with the intact cells is in support of therapeutic role of R-LA as an antioxidant.

A treatment for tardive dyskinesia and some other extrapyramidal symptoms

The effects of the administration of acetazolamide and thiamine (A + T) on the symptoms of tardive dyskinesia (TD) and parkinsonism of 8 elderly and 25 younger chronic hospitalized mental patients were examined in a placebo-controlled, double-blind, counterbalanced two-period cross-over study with initial baselines and intervening washout periods. All patients were maintained on their prestudy psychoactive and anti-Parkinson medications, without alteration, throughout the study. The elderly group received 1.5 g acetazolamide and thiamine per day in three divided doses for 3 weeks. The younger group received 1.5 g thiamine and 2.0 g acetazolamide per day in divided doses for 2 months. Both groups showed a significant decrease in scores on the Abnormal Involuntary Movement Scale (TD) and the Simpson-Angus Neurological Rating Scale (parkinsonism) while on A + T. The A + T effects were unrelated to age, gender, diagnosis, or maintenance medications.