Comparing Urine Specimen Collection Methods for Urinalysis and Culture Agreement: A Paired Sample Design.

OBJECTIVES: The primary aim of this study was to determine if results from clean catch urine specimens agree with results from catheterized specimens in a urogynecology patient population. The secondary aim was to identify clinical scenarios in which catheterized specimens are preferred over clean catch specimens. METHODS: Both a midstream clean catch and a catheterized specimen were obtained for each participant. Dipstick urinalysis was performed. If either specimen was positive for nitrites, leukocyte esterase, or blood then both were sent for urine culture.Kappa statistics were calculated to measure agreement between the paired specimen data for the total sample and for stratified samples. We agreed to accept clean catch results as preferable to catheterized results if the κ statistic was 0.7 or greater. RESULTS: Three hundred forty-two participants were enrolled. For all participants, the agreement between the paired samples was strong for nitrite (κ = 0.884), moderate for blood and colony count (both κ = 0.656), weak for culture species (κ = 0.566), and minimal for leukocyte esterase (κ = 0.382). When data were stratified for menopause, vaginal estrogen use, body mass index, and prolapse, there were no clinical scenarios in which the κ values were consistently greater than our accepted value of 0.7. CONCLUSIONS: Our data indicate that catheterized urine specimens should be used in the evaluation of urinary tract infection or microscopic hematuria in the typical patient presenting to a urogynecology office who is often menopausal, overweight, and may have prolapse.

Sex-Dependent Effects of Nephron Ift88 Disruption on BP, Renal Function, and Cystogenesis.

BACKGROUND: Primary cilia regulation of renal function and BP in health and disease is incompletely understood. This study investigated the effect of nephron ciliary loss on renal physiology, BP, and ensuing cystogenesis. METHODS: Mice underwent doxycycline (DOX)-inducible nephron-specific knockout (KO) of the Ift88 gene at 2 months of age using a Cre-LoxP strategy. BP, kidney function, and renal pathology were studied 2 and 9 months after DOX (Ift88 KO) or vehicle (control). RESULTS: At 2 months post-DOX, male, but not female, Ift88 KO, compared with sex-matched control, mice had reduced BP, enhanced salt-induced natriuresis, increased urinary nitrite and nitrate (NOx) excretion, and increased kidney NOS3 levels, which localized to the outer medulla; the reductions in BP in male mice were prevented by L-NAME. At 9 months post-DOX, male, but not female, Ift88 KO mice had polycystic kidneys, elevated BP, and reduced urinary NOx excretion. No differences were observed in plasma renin concentration, plasma aldosterone, urine vasopressin, or urine PGE2 between Ift88 KO and control mice at 2 or 9 months post-DOX. CONCLUSIONS: Nephron cilia disruption in male, but not female, mice (1) reduces BP prior to cyst formation, (2) increases NOx production that may account for the lower BP prior to cyst formation, and (3) induces polycystic kidneys that are associated with hypertension and reduced renal NO production.

Preoperative urine nitrite versus urine culture for predicting postoperative fever following flexible ureteroscopic lithotripsy: a propensity score matching analysis.

PURPOSE: Multiple studies have reported that preoperative positive urine culture is an independent risk factor for postoperative fever (POF) after ureteroscopy (URS). Urine nitrite is associated urinary tract infections (UTIs). However, none of studies has explored the role of urine nitrite in the prediction of POF after flexible URS (fURS). METHODS: Patients who underwent fURS by the same surgeon between 2009 and 2019 were screened. Sensitivity and specificity of urine culture and urine nitrite were calculated. Propensity score (PS) matching was performed to get a baseline-balanced retrospective cohort to avoid potential bias. Receiver operating characteristic-area under the curve (ROC-AUC) calculated was used to determine the predictive power of models. Decision curve analysis (DCA) was plotted to obtain the clinical benefit of the models. RESULTS: Poseoperative fever (POF) is defined as the temperature of the patient higher than 38 ℃ within 72 h after operation, with no sign of infection in other systems. 31(2.8%) of 1095 cases had POF after fURL. Urine nitrite had a better specificity than urine culture for POF diagnosis (P < 0.001). After the PS matching, a well-balanced cohort of 24 POF group and 96 no-POF group was produced. The mean AUC from the bootstrap resampling method for urine nitrite model (AUC: 0.8736; 95% CI: 0.8731-0.8743) was significantly increased than that of the urine culture model (AUC: 0.8385; 95% CI: 0.8378-0.8392). The application of two kinds of POF predicting models could bring clinical net benefit when the probability is < 35%. However, urine nitrite model showed a better clinical net benefit acquirement compared to the urine culture model. CONCLUSION: Preoperative positive urine nitrite may play a pivotal role in the prediction of POF after fURS and needs to be validated by future evidence.

Pre-exposure to mechanical ventilation and endotoxemia increases Pseudomonas aeruginosa growth in lung tissue during experimental porcine pneumonia.

BACKGROUND: Immune system suppression during critical care contributes to the risk of acquired bacterial infections with Pseudomonas (P.) aeruginosa. Repeated exposure to endotoxin can attenuate systemic inflammatory cytokine responses. Mechanical ventilation affects the systemic inflammatory response to various stimuli. AIM: To study the effect of pre-exposure to mechanical ventilation with and without endotoxin-induced systemic inflammation on P. aeruginosa growth and wet-to-dry weight measurements on lung tissue and plasma and bronchoalveolar lavage levels of tumor necrosis factor alpha, interleukins 6 and 10. METHODS: Two groups of pigs were exposed to mechanical ventilation for 24 hours before bacterial inoculation and six h of experimental pneumonia (total experimental time 30 h): A30h+Etx (n = 6, endotoxin 0.063 µg x kg-1 x h-1) and B30h (n = 6, saline). A third group, C6h (n = 8), started the experiment at the bacterial inoculation unexposed to endotoxin or mechanical ventilation (total experimental time 6 h). Bacterial inoculation was performed by tracheal instillation of 1x1011 colony-forming units of P. aeruginosa. Bacterial cultures and wet-to-dry weight ratio analyses were done on lung tissue samples postmortem. Separate group comparisons were done between A30h+Etx vs.B30h (Inflammation) and B30h vs. C6h (Ventilation Time) during the bacterial phase of 6 h. RESULTS: P. aeruginosa growth was highest in A30h+Etx, and lowest in C6h (Inflammation and Ventilation Time both p<0.05). Lung wet-to-dry weight ratios were highest in A30h+Etx and lowest in B30h (Inflammation p<0.01, Ventilation Time p<0.05). C6h had the highest TNF-α levels in plasma (Ventilation Time p<0.01). No differences in bronchoalveolar lavage variables between the groups were observed. CONCLUSIONS: Mechanical ventilation and systemic inflammation before the onset of pneumonia increase the growth of P. aeruginosa in lung tissue. The attenuated growth of P. aeruginosa in the non-pre-exposed animals (C6h) was associated with a higher systemic TNF-α production elicited from the bacterial challenge.

Sensing of electrolytes in urine using a miniaturized paper-based device.

Analyzing electrolytes in urine, such as sodium, potassium, calcium, chloride, and nitrite, has significant diagnostic value in detecting various conditions, such as kidney disorder, urinary stone disease, urinary tract infection, and cystic fibrosis. Ideally, by regularly monitoring these ions with the convenience of dipsticks and portable tools, such as cellphones, informed decision making is possible to control the consumption of these ions. Here, we report a paper-based sensor for measuring the concentration of sodium, potassium, calcium, chloride, and nitrite in urine, accurately quantified using a smartphone-enabled platform. By testing the device with both Tris buffer and artificial urine containing a wide range of electrolyte concentrations, we demonstrate that the proposed device can be used for detecting potassium, calcium, chloride, and nitrite within the whole physiological range of concentrations, and for binary quantification of sodium concentration.

Renomedullary Interstitial Cell Endothelin A Receptors Regulate BP and Renal Function.

BACKGROUND: The physiologic role of renomedullary interstitial cells, which are uniquely and abundantly found in the renal inner medulla, is largely unknown. Endothelin A receptors regulate multiple aspects of renomedullary interstitial cell function in vitro. METHODS: To assess the effect of targeting renomedullary interstitial cell endothelin A receptors in vivo, we generated a mouse knockout model with inducible disruption of renomedullary interstitial cell endothelin A receptors at 3 months of age. RESULTS: BP and renal function were similar between endothelin A receptor knockout and control mice during normal and reduced sodium or water intake. In contrast, on a high-salt diet, compared with control mice, the knockout mice had reduced BP; increased urinary sodium, potassium, water, and endothelin-1 excretion; increased urinary nitrite/nitrate excretion associated with increased noncollecting duct nitric oxide synthase-1 expression; increased PGE2 excretion associated with increased collecting duct cyclooxygenase-1 expression; and reduced inner medullary epithelial sodium channel expression. Water-loaded endothelin A receptor knockout mice, compared with control mice, had markedly enhanced urine volume and reduced urine osmolality associated with increased urinary endothelin-1 and PGE2 excretion, increased cyclooxygenase-2 protein expression, and decreased inner medullary aquaporin-2 protein content. No evidence of endothelin-1-induced renomedullary interstitial cell contraction was observed. CONCLUSIONS: Disruption of renomedullary interstitial cell endothelin A receptors reduces BP and increases salt and water excretion associated with enhanced production of intrinsic renal natriuretic and diuretic factors. These studies indicate that renomedullary interstitial cells can modulate BP and renal function under physiologic conditions.

Preoperative positive urine nitrite and albumin-globulin ratio are independent risk factors for predicting postoperative fever after retrograde Intrarenal surgery based on a retrospective cohort.

BACKGROUND: To determine risk factors for postoperative fever (POF) after retrograding intrarenal surgery (RIRS) and a nomogram for prediction of POF in patients undertaking RIRS has been developed based on the risk factors found. METHODS: This is a retrospective designed-study. A continuous cohort from a single-center database that consisted of 1095 cases undertaking RIRS with complete preoperative medical records from January 2009 to December 2018 was obtained. Independent risk factors were identified according to the multi-variate logistics regression and a further nomogram was developed. The performance of the nomogram was evaluated through three aspects including net clinical benefit, calibration, and discrimination. RESULTS: A total of 31(2.8%) cases had POF after the RIRS. Risk factors included time in RIRS ≥30mins (only the flexible scope use period) (OR: 2.16, 95%CI; 1.01-4.62, P = 0.047), preoperative positive urine culture (OR: 2.55, 95%CI; 1.01-6.42, P = 0.047), preoperative positive urine nitrite (OR: 9.09, 95%CI; 2.99-27.64, P < 0.001), Albumin/globulin ratio (AGR) (OR: 0.14, 95%CI; 0.03-0.74, P = 0.020) were further included in the nomogram to predict the POF probability for individuals. The Hosmer-Lemeshow test showed a goodness-of-fit. The calibration curve demonstrated good agreement between observation and prediction. Decision curve analysis (DCA) demonstrated it was clinical use in RIRS. CONCLUSIONS: The preoperative urine nitrite, AGR, RIRS time, and preoperative urine culture are found to be independent risk factors associated with POF after RIRS. Then we have developed a nomogram taking these factors into account that accurately predicted POF after RIRS.

New participant stratification and combination of urinary biomarkers and confounders could improve diagnostic accuracy for overactive bladder.

Overactive bladder (OAB) is a highly prevalent symptom complex characterised by symptoms of urinary urgency, increased frequency, nocturia, with or without urge incontinence; in the absence of proven infection or other obvious pathology. The underlying pathophysiology of idiopathic OAB is not clearly known and the existence of several phenotypes has been proposed. Current diagnostic approaches are based on discordant measures, suffer from subjectivity and are incapable of detecting the proposed OAB phenotypes. In this study, cluster analysis was used as an objective approach for phenotyping participants based on their OAB characteristic symptoms and led to the identification of a low OAB symptomatic score group (cluster 1) and a high OAB symptomatic score group (cluster 2). Furthermore, the ability of several potential OAB urinary biomarkers including ATP, ACh, nitrite, MCP-1 and IL-5 and participants' confounders, age and gender, in predicting the identified high OAB symptomatic score group was assessed. A combination of urinary ATP and IL-5 plus age and gender was shown to have clinically acceptable and improved diagnostic accuracy compared to urodynamically-observed detrusor overactivity. Therefore, this study provides the foundation for the development of novel non-invasive diagnostic tools for OAB phenotypes that may lead to personalised treatment.

Squamous epithelial cell presence reduces accuracy of urinalysis for prediction of positive urine cultures.

BACKGROUND: Diagnostic value of urinalysis specimens contaminated with squamous epithelial cells (SEC) from the genital surfaces is assumed to be limited compared to clean-catch samples. However, no studies have quantified the change in predictive value in the presence of SECs for individual urinalysis markers. METHODS: In a retrospective, single center cohort study, we analyzed all urine cultures sent from the ED over a 26-month period with corresponding urinalysis results. Cultures were classified as positive with growth of >104 colony forming units of pathogenic bacteria, negative if no growth, or contaminated for all other results. UA specimens were classified as contaminated or clean based on SEC presence. Accuracy of urinalysis markers for prediction of positive cultures was calculated as an area under the curve (AUC) and was compared between contaminated and clean UA specimens. RESULTS: 6490 paired UA and urine cultures were analyzed, consisting of 3949 clean and 2541 contaminated samples. SEC presence was less common with male gender, older age, and smaller BMI. Urine cultures were 19.2% positive overall, and SECs were more common in contaminated cultures. AUCs for individual markers ranged from 0.557 to 0.796, with pyuria, bacteriuria, and leukocyte esterase having higher AUC in clean samples over contaminated. CONCLUSION: Analysis of AUC for individual urinalysis markers showed reduced diagnostic accuracy in the presence of SECs. SEC presence also reflected much higher rates of contaminated cultures. These results support the reduced reliance on contaminated UA specimens for ruling in UTI in ED patients.

Current practice on the management of pre-operative urine dipstick results in women undergoing gynaecological surgery in Wales.

A survey was circulated to consultant gynaecologists across Wales, to evaluate the management of pre-operative urine dipstick results. Questions were based on NICE guideline 171, regarding the management of urinary incontinence in women. Six respondents never checked their patient's urine dipstick results. Of the remaining 37 respondents, 70% always check and 30% sometimes check. Overall, 37.1% cancelled surgery when a urine dipstick was positive for either nitrite or leukocyte-esterase (LE). A significantly larger proportion cancelled surgery when symptomatic for urinary tract infection (p< 0.001), and when nitrite and LE positive compared to only LE positive (p< 0.05). This survey provides evidence that gynaecological operations are potentially being cancelled unnecessarily based on a screening test with limited sensitivity and specificity. Further research is needed into the outcomes of gynaecological surgery in women symptomatic of urinary tract infection to provide guidance on the use of pre-operative urinalysis and the management of test results. Impact statement What is already known on this subject? The strongest risk factor for postoperative urinary tract infections (UTIs) is a pre-operative recurrent UTI (Nygaard et al. 2011 ). This is the reason behind the urine dipstick being part of the pre-operative checklist for gynaecological surgery. Traditionally, a suspected UTI would mean postphoning surgery whilst treating the UTI. It is known that the sensitivity of the nitrite test and leukocyte-esterase test when used alone is low and cannot rule out UTI in most patients (Mambatta et al. 2015 ). Urine culture is therefore suggested for all patients with a suspected UTI (John et al. 2006 ). To our knowledge, there are no data available on whether we should be postphoning gynaecological surgery based on a urine dipstick result. What the results of this study add? Overall, 37.1% of respondents cancelled surgery when a pre-operative urine dipstick was positive for either nitrite or leukocyte-esterase. This provides evidence of variation in the practice of using the urine dipstick in women undergoing gynaecological surgery in Wales. These cancellations are potentially unnecessarily. Furthermore, 14% of respondents did not use a urine dipstick and the majority did not act on an abnormal results, implying clinicians have a low confidence in the test as a screening tool. What the implications are of these findings for clinical practice and/or further research? We propose removing the urine dipstick as a pre-operative screening test. Asymptomatic bacteriuria is common in women and routine screening for UTI pre-operatively will therefore inevitably lead to unnecessary intervention (i.e. cancellation). Further research is needed into the outcomes of gynaecological surgery in women symptomatic of UTI to be able to provide guidance on the use of pre-operative urinalysis and management of the test results.

Consumption of Nitrate-Rich Beetroot Juice with or without Vitamin C Supplementation Increases the Excretion of Urinary Nitrate, Nitrite, and N-nitroso Compounds in Humans.

Consumption of nitrate-rich beetroot juice (BRJ) by athletes induces a number of beneficial physiological health effects, which are linked to the formation of nitric oxide (NO) from nitrate. However, following a secondary pathway, NO may also lead to the formation of N-nitroso compounds (NOCs), which are known to be carcinogenic in 39 animal species. The extent of the formation of NOCs is modulated by various other dietary factors, such as vitamin C. The present study investigates the endogenous formation of NOCs after BRJ intake and the impact of vitamin C on urinary NOC excretion. In a randomized, controlled trial, 29 healthy recreationally active volunteers ingested BRJ with or without additional vitamin C supplements for one week. A significant increase of urinary apparent total N-nitroso Compounds (ATNC) was found after one dose (5 to 47 nmol/mmol: p < 0.0001) and a further increase was found after seven consecutive doses of BRJ (104 nmol/mmol: p < 0.0001). Vitamin C supplementation inhibited ATNC increase after one dose (16 compared to 72 nmol/mmol, p < 0.01), but not after seven daily doses. This is the first study that shows that BRJ supplementation leads to an increase in formation of potentially carcinogenic NOCs. In order to protect athlete's health, it is therefore important to be cautious with chronic use of BRJ to enhance sports performances.

Pharmacological preconditioning with inhaled nitric oxide (NO): Organ-specific differences in the lifetime of blood and tissue NO metabolites.

BACKGROUND: Endogenous nitric oxide (NO) may contribute to ischemic and anesthetic preconditioning while exogenous NO protects against ischemia-reperfusion (I/R) injury in the heart and other organs. Why those beneficial effects observed in animal models do not always translate into clinical effectiveness remains unclear. To mitigate reperfusion damage a source of NO is required. NO inhalation is known to increase tissue NO metabolites, but little information exists about the lifetime of these species. We therefore sought to investigate the fate of major NO metabolite classes following NO inhalation in mice in vivo. METHODS: C57BL/6J mice were exposed to 80 ppm NO for 1 h. NO metabolites were measured in blood (plasma and erythrocytes) and tissues (heart, liver, lung, kidney and brain) immediately after NO exposure and up to 48 h thereafter. Concentrations of S-nitrosothiols, N-nitrosamines and NO-heme products as well as nitrite and nitrate were quantified by gas-phase chemiluminescence and ion chromatography. In separate experiments, mice breathed 80 ppm NO for 1 h prior to cardiac I/R injury (induced by coronary arterial ligation for 1 h, followed by recovery). After sacrifice, the size of the myocardial infarction (MI) and the area at risk (AAR) were measured. RESULTS: After NO inhalation, elevated nitroso/nitrosyl levels returned to baseline over the next 24 h, with distinct multi-phasic decay profiles in each compartment. S/N-nitroso compounds and NO-hemoglobin in blood decreased exponentially, but remained above baseline for up to 30min, whereas nitrate was elevated for up to 3hrs after discontinuing NO breathing. Hepatic S/N-nitroso species concentrations remained steady for 30min before dropping exponentially. Nitrate only rose in blood, liver and kidney; nitrite tended to be lower in all organs immediately after NO inhalation but fluctuated considerably in concentration thereafter. NO inhalation before myocardial ischemia decreased the ratio of MI/AAR by 30% vs controls (p = 0.002); only cardiac S-nitrosothiols and NO-hemes were elevated at time of reperfusion onset. CONCLUSIONS: Metabolites in blood do not reflect NO metabolite status of any organ. Although NO is rapidly inactivated by hemoglobin-mediated oxidation in the circulation, long-lived tissue metabolites may account for the myocardial preconditioning effects of inhaled NO. NO inhalation may afford similar protection in other organs.

Prediction of Bacteriuria Based on Clinical or Laboratory Parameters in Patients with Indwelling Ureteral Stents Before Ureterorenoscopy Should Not Substitute for Urine Cultures.

OBJECTIVES: Urine cultures before secondary ureterorenoscopy (URS) are recommended to exclude bacteriuria, but results are often pending on the day of surgery. We sought to develop predictive models that reliably indicate the absence of bacteriuria in patients with indwelling ureteral stents based on readily available data. PATIENTS AND METHODS: Records of patients undergoing secondary URS between 2014 and 2017 were assessed retrospectively. Patient characteristics, automated urinary sediment analysis, blood analyses, and results of urine cultures were analyzed using descriptive statistics, receiver operating characteristic curves, logistic regression, and model selection. RESULTS: Of 462 patients, 101 (21.9%) had positive urine cultures. Urinary leucocytes, nitrite and pH, patient age and sex, and blood C-reactive protein (CRP) levels were associated with bacteriuria in logistic regression (p < 0.05), but did not sharply separate patients with and without bacteriuria. A multiple logistic regression model considering all six parameters and their interactions indicated a low probability of bacteriuria (8%) for 74% of the patients. Alternatively, recursive partitioning indicated low probability of bacteriuria (8%) if four criteria are simultaneously fulfilled (54% of the patients): Male, negative nitrite, urine leucocytes ≤1174/µL, and blood CRP ≤13 mg/L. CONCLUSIONS: Bacteriuria in patients with indwelling ureteral stents before URS can hardly be predicted based on single clinical or laboratory parameters. Although the combination of relevant predictors allows for exclusion of urinary tract infection with relatively high confidence in most patients, the residual diagnostic uncertainty calls for optimized organizational measures to assure availability of urine cultures before surgery.

Disparity of nitrate and nitrite in vivo in cancer villages as compared to other areas in Huai River Basin, China.

Saliva and Urine samples were collected for the study on how nitrate and nitrite concentration in human body may be related to the corresponding health risk in a high cancer incidence area. The study area includes three known cancer villages in Huai River basin, China. The results of analyzing collected sample show that there are higher levels of nitrate and nitrite concentration in human saliva and urine sample collected in the study area as compared to those collected in other areas. In addition, levels of nitrate and nitrite concentration in saliva and urine sample change significantly with the ages of sampled population. NO3-concentrations in saliva and urine sample are the most outstanding among the middle-aged and elderly populations. It means that the middle-aged and elderly populations have relatively high vivo nitrate reductive transformation rates and they also have higher N-nitroso compounds synthesis risks in the studied cancer villages.

Performance of the dipstick screening test as a predictor of negative urine culture / Desempenho da fita de urina como resultado presuntivo para cultura de urina negativa

ABSTRACT Objective To investigate whether the urine dipstick screening test can be used to predict urine culture results. Methods A retrospective study conducted between January and December 2014 based on data from 8,587 patients with a medical order for urine dipstick test, urine sediment analysis and urine culture. Sensitivity, specificity, positive and negative predictive values were determined and ROC curve analysis was performed. Results The percentage of positive cultures was 17.5%. Nitrite had 28% sensitivity and 99% specificity, with positive and negative predictive values of 89% and 87%, respectively. Leukocyte esterase had 79% sensitivity and 84% specificity, with positive and negative predictive values of 51% and 95%, respectively. The combination of positive nitrite or positive leukocyte esterase tests had 85% sensitivity and 84% specificity, with positive and negative predictive values of 53% and 96%, respectively. Positive urinary sediment (more than ten leukocytes per microliter) had 92% sensitivity and 71% specificity, with positive and negative predictive values of 40% and 98%, respectively. The combination of nitrite positive test and positive urinary sediment had 82% sensitivity and 99% specificity, with positive and negative predictive values of 91% and 98%, respectively. The combination of nitrite or leukocyte esterase positive tests and positive urinary sediment had the highest sensitivity (94%) and specificity (84%), with positive and negative predictive values of 58% and 99%, respectively. Based on ROC curve analysis, the best indicator of positive urine culture was the combination of positives leukocyte esterase or nitrite tests and positive urinary sediment, followed by positives leukocyte and nitrite tests, positive urinary sediment alone, positive leukocyte esterase test alone, positive nitrite test alone and finally association of positives nitrite and urinary sediment (AUC: 0.845, 0.844, 0.817, 0.814, 0.635 and 0.626, respectively). Conclusion A negative urine culture can be predicted by negative dipstick test results. Therefore, this test may be a reliable predictor of negative urine culture.

RESUMO Objetivo Verificar se a triagem de urina por fitas reativas é capaz de predizer a cultura de urina. Métodos Estudo retrospectivo realizado entre janeiro e dezembro de 2014 com 8.587 pacientes, com solicitação médica de triagem de urina (fita), sedimento urinário e cultura de urina. Foram analisados sensibilidade, especificidade, valor preditivo positivo, valor preditivo negativo e curva ROC. Resultados Foram positivas 17,5% das culturas. O nitrito apresentou sensibilidade de 28% e especificidade de 99%. O valor preditivo positivo foi de 89% e o valor preditivo negativo de 87%. Esterase apresentou sensibilidade de 79% e especificidade de 84%. Valor preditivo positivo e valor preditivo negativo foram de 51% e 95%, respectivamente. A combinação de nitrito ou esterase positivos apresentou sensibilidade de 85% e especificidade de 84%. Valor preditivo positivo e valor preditivo negativo foram, respectivamente, 53% e 96%. O sedimento positivo (mais de dez leucócitos por microlitro) apresentou sensibilidade de 92% e especificidade de 71%. O valor preditivo positivo foi 40% e o negativo, 98%. A combinação de nitrito e sedimento urinário positivos apresentou sensibilidade de 82% e especificidade de 99%. Os valores preditivos positivo e negativo foram 91% e 98%, respectivamente. Para o nitrito ou esterase positivos mais os leucócitos positivos, a sensibilidade foi de 94% e a especificidade de 84%. O valor preditivo positivo foi de 58% e o negativo foi de 99%. Com base na curva ROC, o melhor indicador de urocultura positiva foi a associação entre a esterase ou nitrito positivos na fita mais os leucócitos positivos no sedimento, seguido por nitrito e esterase positivos, sedimento urinário positivo isolado, esterase positiva isolada, nitrito positivo isolado e, finalmente, pela associação entre nitrito e sedimento urinário positivos (AUC: 0,845, 0,844, 0,817, 0,814, 0,635 e 0,626, respectivamente). Conclusão Uma urocultura negativa pode ser prevista com resultados negativos na fita. Portanto, este teste pode ser um preditor confiável de urocultura negativa.

Predictors for uroseptic shock in patients who undergo minimally invasive percutaneous nephrolithotomy.

To identify risk factors that can predict which patient is likely to progress from systemic inflammatory response syndrome (SIRS) to uroseptic shock after minimally invasive percutaneous nephrolithotomy (MPCNL) for the upper urinary tract stones. We retrospectively reviewed 156 patients who suffered infectious complications after MPCNL from March 2014 to February 2016. Perioperative risk factors that could potentially contribute to uroseptic shock were compared to those of patients with only SIRS. 135 of the 156 patients developed to SIRS only, the remaining 21 patients progressed to uroseptic shock. The rate of positive preoperative urine nitrite was significantly higher (p < 0.001), stone diameter was larger (p = 0.015) and operative time was longer (p < 0.001) in uroseptic shock group. Multivariable logistic analysis showed that preoperative urine nitrite (OR 10.570, p = 0.025), stone size (OR 11.512, p = 0.009) and postoperative blood leukopenia (OR 0.009, p < 0.001) were independently related to uroseptic shock. Moreover, ROC curve analysis showed that white blood count threshold within the first 3 h of uroseptic shock was 2.98 × 109/L. The sensitivity and specificity of leukocyte count in predicting uroseptic shock were 90.5 and 92.6%, respectively. Preoperative urine nitrite, stone size and postoperative leukocyte count are statistically linked to uroseptic shock after MPCNL. Leukopenia of less than 2.98 × 109/L within 3 h after MPCNL can be a predictor for uroseptic shock. For patients who have high risk factors for developing uroseptic shock, the white blood count should be measured within 3 h after MPCNL.

Elevated urinary levels of carcinogenic N-nitrosamines in patients with urinary tract infections measured by isotope dilution online SPE LC-MS/MS.

N-nitrosamines (NAms) are well-documented for their carcinogenic potential. Human exposure to NAms may arise from the daily environment and endogenous formation via the reaction of secondary amines with nitrites or from bacteria infection. We describe the use of isotope dilution online solid-phase extraction (SPE) LC-MS/MS to quantify nine NAms in human urine. This method was validated and further applied to healthy subjects and patients with urinary tract infection (UTI). N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR) and N-nitrosomorpholine (NMOR) were analyzed with an APCI source, while N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosodi-n-propylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA) were quantified with an ESI source, due to their effect on the sensitivity and chromatography. NDMA was the most abundant N-nitrosamine, while NDPhA was firstly identified in human. UTI patients had three to twelve-fold higher concentrations for NDMA, NPIP, NDEA, NMOR and NDBA in urine than healthy subjects, and the NAms were significantly decreased after antibiotics treatment. NDMA concentrations were also significantly correlated with the pH value, leukocyte esterase activity or nitrite in urines of UTI patients. Our findings by online SPE LC-MS/MS method evidenced that UTI patients experienced various NAms exposures, especially the potent carcinogen NDMA, which was likely induced by bacteria infection.

Urinary levels of N-nitroso compounds in relation to risk of gastric cancer: findings from the shanghai cohort study.

BACKGROUND: N-Nitroso compounds are thought to play a significant role in the development of gastric cancer. Epidemiological data, however, are sparse in examining the associations between biomarkers of exposure to N-nitroso compounds and the risk of gastric cancer. METHODS: A nested case-control study within a prospective cohort of 18,244 middle-aged and older men in Shanghai, China, was conducted to examine the association between urinary level of N-nitroso compounds and risk of gastric cancer. Information on demographics, usual dietary intake, and use of alcohol and tobacco was collected through in-person interviews at enrollment. Urinary levels of nitrate, nitrite, N-nitroso-2-methylthiazolidine-4-carboxylic acid (NMTCA), N-nitrosoproline (NPRO), N-nitrososarcosine (NSAR), N-nitrosothiazolidine-4-carboxylic acid (NTCA), as well as serum H. pylori antibodies were quantified in 191 gastric cancer cases and 569 individually matched controls. Logistic regression method was used to assess the association between urinary levels of N-nitroso compounds and risk of gastric cancer. RESULTS: Compared with controls, gastric cancer patients had overall comparable levels of urinary nitrate, nitrite, and N-nitroso compounds. Among individuals seronegative for antibodies to H. pylori, elevated levels of urinary nitrate were associated with increased risk of gastric cancer. The multivariate-adjusted odds ratios for the second and third tertiles of nitrate were 3.27 (95% confidence interval = 0.76-14.04) and 4.82 (95% confidence interval = 1.05-22.17), respectively, compared with the lowest tertile (P for trend = 0.042). There was no statistically significant association between urinary levels of nitrite or N-nitroso compounds and risk of gastric cancer. Urinary NMTCA level was significantly associated with consumption of alcohol and preserved meat and fish food items. CONCLUSION: The present study demonstrates that exposure to nitrate, a precursor of N-nitroso compounds, may increase the risk of gastric cancer among individuals without a history of H. pylori infection.

Effectiveness of an association of a cranberry dry extract, D-mannose, and the two microorganisms Lactobacillus plantarum LP01 and Lactobacillus paracasei LPC09 in women affected by cystitis: a pilot study.

BACKGROUND: Urinary tract infections (UTIs) are the most common bacterial infection in women. Most UTIs are acute uncomplicated cystitis caused by Escherichia coli (86%). This study was undertaken to assess the effectiveness of an association of a cranberry dry extract, D-mannose, a gelling complex composed of the exopolysaccharides produced by Streptococcus thermophilus ST10 (DSM 25246) and tara gum, as well as the 2 microorganisms Lactobacillus plantarum LP01 (LMG P-21021) and Lactobacillus paracasei LPC09 (DSM 24243) in women affected by acute uncomplicated cystitis. MATERIALS AND METHODS: Thirty-three premenopausal, nonpregnant women diagnosed with acute uncomplicated cystitis were enrolled in a pilot prospective study and completed the treatment protocol. Subjects were instructed to take 2 doses per day during the first month, and then to continue with 1 sachet per day until the sixtieth day. Nitrites and leukocyte esterase on urine dipstick testing were used as indicators of cystitis, with analysis performed at enrollment, after 30 and 60 days, and after 1 month of follow-up. Typical UTI symptoms, namely dysuria, frequent voiding of small volumes, urinary urgency, suprapubic pain, and gross hematuria were scored 0 to 3 and evaluated at each visit. RESULTS: Positive results for the presence of nitrites and leukocyte esterase were found in 14 and 20 subjects after 30 days and in 9 and 14 women after 60 days, respectively (P<0.001). At the end of the follow-up period, positive results for nitrites and leukocyte esterase were recorded in only 4 and 3 of 24 and 19 subjects (16.7%, P=0.103; 15.8%, P=0.325, respectively), with negative results after 60 days. Typical symptoms of cystitis, specifically dysuria, frequent voiding, urgency, and suprapubic pain were significantly improved as well. No significant differences were recorded in the incidence and severity of hematuria at any visit. CONCLUSION: The long-term ability of an association of cranberry, D-mannose, an innovative gelling complex, and the 2 microorganisms tested to significantly improve the uncomfortable symptoms reported by women with acute cystitis has been suggested.