Normative noninvasive bladder function measurements in healthy women: A systematic review and meta-analysis

AIM

To conduct an evidence synthesis of normative reference values for bladder function parameters in women.

METHODS

We conducted a systematic review and meta-analysis of studies reporting bladder function parameters obtained from noninvasive tests in healthy women. Seven databases were searched for relevant studies from inception through December 2018, with manual searching of reference lists. We included English language articles that provided quantitative data on urination frequency, voided and postvoid residual volumes, and uroflowmetry results in women without lower urinary tract symptoms. Study selection, data extraction, and quality assessment were undertaken by at least two independent reviewers. Random-effects meta-analytic models were used to derive study-level pooled mean estimates and 95% confidence intervals.

RESULTS

A total of 24 studies (N = 3090 women, age range, 18-91 years) met eligibility criteria. Pooled mean estimates of bladder function parameters were: 6.6 daytime voids (95% confidence interval (95% CI), 6.2, 7.0), 0.4 nighttime voids (95% CI, 0.0, 0.8), 1577 mL for 24-hour voided volume (95% CI 1428,1725); 12 mL for postvoid residual volume (95% CI, 4, 20); and 28 mL/sec for maximum flow rate (95% CI, 27,30). Between-study heterogeneity was high for all outcomes (I²  = 61.1-99.6%), but insufficient data were available to explore reasons for this high heterogeneity (eg, differences by age).

CONCLUSION

Although summary mean estimates of bladder function parameters were calculated, the wide heterogeneity across studies precludes generalization of these estimates to all healthy women. Further research is needed to determine normative reference values within specific groups, such as those defined by age.

Water and other fluids in nephrolithiasis: State of the art and future challenges

Adequate hydration, as to maintain urinary volume over 2 L/day, has long been considered as the cornerstone medical prescription for preventing nephrolithiasis. However, scientific evidence about what kind of water stone formers should drink and about the effects of other beverages on urinary stone risk factors is sometimes unclear. Moreover, the recommendation that water therapy prevents kidney stone recurrence relies on only one randomized controlled trial, even if more epidemiologic and basic science studies seem to support this assumption. Therefore, in this review we analyze current evidence that support water therapy in nephrolithiasis and we highlight the possible effects of different types of water and other beverages on lithogenic risk, giving some practical recommendations for what stone formers should be advised to prevent recurrence.

24-Hour Urine Samples Are More Reproducible Than Spot Urine Samples for Evaluation of Iodine Status in School-Age Children

BACKGROUND

Variation in different urinary measurements for evaluation of iodine status is of concern to clinicians and researchers.

OBJECTIVE

This study evaluated variations between urine iodine concentration (UIC), spot and 24-h urine sample creatinine concentrations, and 24-h urine iodine excretion (24-h UIE) in repeated samples from school-age children.

METHODS

Urine samples (24 h and morning spot) were collected on 2 occasions from 981 children in Ningjin and Lingxian counties, China. Samples from Ningjin were collected in October and November 2013, and samples from Lingxian were collected in April and May 2014. Morning spot urine iodine concentration (MUIC), morning spot urine creatinine, 24-h UIC, and 24-h urine creatinine were measured in all samples. The 24-h UIE was calculated by multiplying the 24-h UIC by the 24-h urine volume.

RESULTS

In Ningjin County, the 24-h UIC and 24-h UIE did not differ between repeated collections [192 and 172 μg/L, respectively, for 24-h UIC (P = 0.08); 123 and 120 μg/L, respectively, for 24-h UIE (P = 0.56)], whereas the MUIC was lower in November 2013 than in October 2013 (170 and 190 μg/L, respectively; P = 0.034). In Lingxian County, no significant differences were observed in 24-h UIC between the repeated collections (230 and 218 μg/L, respectively; P = 0.79), whereas the 24-h UIE and MUIC were higher in the samples collected in May 2014 than in April 2014 [161 and 155 μg/L, respectively, for 24-h UIE (P = 0.002); 244 and 203 μg/L, respectively, for MUIC (P < 0.001)]. When data from both counties were combined, no difference was observed between repeated 24-h UIC (214 compared with 196 μg/L; P = 0.17) and 24-h UIE (143 compared with 143 μg/d; P = 0.06), but MUICs were lower in the first collection than in the second collection (199 and 207 μg/L, respectively; P = 0.002). The κ values were >0.4 for 24-h UIC and mean UIE, whereas relatively low κ values were observed for MUIC and mean UIE.

CONCLUSION

The 24-h UIC was more accurate and reproducible than the MUIC in evaluating iodine status in a large-scale population study of school-age children.

Influence of mesenchymal stem cells on expression of AQP1 and AQP2 in rats with nephropathy induced by adriamycin

This study aims to explore the therapeutic effect of bone marrow mesenchymal stem cells on adriamycin nephrosis, and the potential mechanism. The rat experimental nephropathy model was established by unilateral nephrectomy combined repeated injecting adriamycin (ADR). Thirty adriamycin nephrosis rats were randomly divided into three groups, including ADR (n=10), MSCs transplantation through peripheral veins groups (M-V, n=10), and MSCs transplantation through right renal artery groups (M-A, n=10), and there was another normal control group (N, n=10). This study lasted 8 weeks, 24 hours urine was collected through simple metabolic cage to measure urinary volume and urine protein quantitation in 24 hours. The levels of plasma albumin (ALB), sodium were measured by biochemical analysis. The expressions of AQP1-2 were measured by immuno-histochemistry assay. Kidney medulla ultramicroscopic structure was observed by TEM. The results indicated that the ALB and 24 h urinary volume have significant increased in M-V and M-A group compared to the ADR group (P<0.05). Furthermore, the serum sodium and urine protein quantitation in 24 hours were decreased in M-V and M-A group compared to ADR group (P<0.05). Protein expression of AQP1-2 had been remarkably decreased (P<0.05). It showed degenerative changes of kidney ultra microscopic structures of the ADR rats, while MSCs transplantation could significantly improve the damage. In conclusion, in adriamycin nephropathy rats, MSCs transplantation exerts its therapeutic effects by decrease urinary albumin excretion, increase ALB, decrease sodium and the expression of AQP1-2 in renal tubules.