Dilute Urine Research Articles

Cannabinoid receptor type 1 activation causes a water diuresis by inducing an acute central diabetes insipidus in mice.

Cannabis and synthetic cannabinoid consumption are increasing worldwide. Cannabis contains numerous phytocannabinoids that act on the G protein-coupled cannabinoid receptor type 1 (CB1R) and cannabinoid receptor type 2 expressed throughout the body, including the kidney. Essentially every organ, including the kidney, produces endocannabinoids, which are endogenous ligands to these receptors. Cannabinoids acutely increase urine output in rodents and humans, thus potentially influencing total body water and electrolyte homeostasis. As the kidney collecting duct (CD) regulates total body water, acid/base, and electrolyte balance through specific functions of principal cells (PCs) and intercalated cells (ICs), we examined the cell-specific immunolocalization of CB1R in the mouse CD. Antibodies against either the C-terminus or N-terminus of CB1R consistently labeled aquaporin 2 (AQP2)-negative cells in the cortical and medullary CD and thus presumably ICs. Given the well-established role of ICs in urinary acidification, we used a clearance approach in mice that were acid loaded with 280 mM NH4Cl for 7 days and nonacid-loaded mice treated with the cannabinoid receptor agonist WIN55,212-2 (WIN) or a vehicle control. Although WIN had no effect on urinary acidification, these WIN-treated mice had less apical + subapical AQP2 expression in PCs compared with controls and developed acute diabetes insipidus associated with the excretion of large volumes of dilute urine. Mice maximally concentrated their urine when WIN and 1-desamino-8-d-arginine vasopressin [desmopressin (DDAVP)] were coadministered, consistent with central rather than nephrogenic diabetes insipidus. Although ICs express CB1R, the physiological role of CB1R in this cell type remains to be determined.NEW & NOTEWORTHY The CB1R agonist WIN55,212-2 induces central diabetes insipidus in mice. This research integrates existing knowledge regarding the diuretic effects of cannabinoids and the influence of CB1R on vasopressin secretion while adding new mechanistic insights about total body water homeostasis. Our findings provide a deeper understanding about the potential clinical impact of cannabinoids on human physiology and may help identify targets for novel therapeutics to treat water and electrolyte disorders such as hyponatremia and volume overload.

Environmental pollutant risk factors for worse COVID-19 related clinical outcomes in predominately hispanic and latino populations

BackgroundPer- and poly-fluorinated compounds (PFAS) and heavy metals constitute two classes of environmental exposures with known immunotoxicant effects. In this pilot study, we aimed to evaluate the impact of exposure to heavy metals and PFAS on COVID-19 severity. We hypothesized that elevated plasma-PFAS concentrations and urinary heavy metal concentrations would be associated with increased odds of ICU admission in COVID-19 hospitalized individuals. MethodsUsing the University of Southern California Clinical Translational Sciences Institute (SC-CTSI) biorepository of hospitalized COVID-19 patients, urinary concentrations of 15 heavy metals and urinary creatinine were measured in n = 101 patients and plasma concentrations of 13 PFAS were measured in n = 126 patients. COVID-19 severity was determined based on whether a patient was admitted to the ICU during hospitalization. Associations of metals and PFAS with ICU admission were assessed using logistic regression models, controlling for age, sex, ethnicity, smoking status, and for metals, urinary dilution. ResultsThe average age of patients was 55 ± 14.2 years. Among SC-CTSI participants with urinary measurement of heavy metals and blood measures of PFAS, 54.5% (n = 61) and 54.8% (n = 80) were admitted to the ICU, respectively. For heavy metals, we observed higher levels of Cd, Cr, and Cu in ICU patients. The strongest associations were with Cadmium (Cd). After accounting for covariates, each 1 SD increase in Cd resulted in a 2.00 (95% CI: 1.10–3.60; p = 0.03) times higher odds of admission to the ICU. When including only Hispanic or Latino participants, the effect estimates between cadmium and ICU admission remained similar. Results for PFAS were less consistent, with perfluorodecanesulfonic acid (PFDS) exhibiting a positive but non-significant association with ICU admission (Odds ratio, 95% CI: 1.50, 0.97–2.20) and perfluorodecanoic acid (PFDA) exhibiting a negative association with ICU admission (0.53, 0.31–0.88). ConclusionsThis study supports the hypothesis that environmental exposures may impact COVID-19 severity.

Kidney collecting-duct-derived vasopressin is not essential for appropriate concentration or dilution of urine.

We previously showed that kidney collecting ducts make vasopressin. However, the physiologic role of collecting-duct-derived vasopressin is uncertain. We hypothesized that collecting-duct-derived vasopressin was required for appropriate concentration of urine. We developed a vasopressin conditional knockout mouse model wherein Cre recombinase expression induces deletion of Avp exon 1 in the distal nephron. We then used age-matched 8 - 12 week old Avp fl/fl;Ksp-Cre(-) (WT) and Avp fl/fl;Ksp-Cre(+) mice for all experiments. We collected urine, serum, and kidney lysates at baseline. We then challenged both WT and KO mice with 24 hour water restriction, water loading, and administration of the vasopressin type 2 receptor (V2R) agonist desmopressin (dDAVP) 1 µg/kg/ip) followed by V2R antagonist OPC-31260 (10 mg/kg/ip). We performed immunofluorescence and immunoblot analysis at baseline and confirmed vasopressin knockout in the collecting duct. We found that urinary osmolality (UOsm), plasma Na+, K+, Cl-, BUN, and copeptin were similar in WT vs KO mice at baseline. Immunoblots of vasopressin regulated proteins Na:K:2Cl cotransporter (NKCC2), Na:Cl cotransporter (NCC) and water channel aquaporin-2 (AQP2) showed no difference in expression or phosphorylation at baseline. Following 24 hour water restriction, WT and KO mice had no differences in UOsm, plasma Na+, K+, Cl-, BUN or copeptin. Additionally, there were no differences in the rate of urinary concentration or dilution as WT and KO mice UOsm was nearly identical after dDAVP and OPC-31260 administration. We conclude that collecting-duct-derived vasopressin is not essential to appropriately concentrate or dilute urine.

Urinary concentrations of phthalate metabolites in relation to preeclampsia and other hypertensive disorders of pregnancy in the environmental influences on child health outcomes (ECHO) program

BackgroundPhthalate exposure may contribute to hypertensive disorders of pregnancy (HDP), including preeclampsia/eclampsia (PE/E), but epidemiologic studies are lacking. ObjectivesTo evaluate associations of pregnancy phthalate exposure with development of PE/E and HDP. MethodsUsing data from 3,430 participants in eight Environmental influences on Child Health Outcomes (ECHO) Program cohorts (enrolled from 1999 to 2019), we quantified concentrations of 13 phthalate metabolites (8 measured in all cohorts, 13 in a subset of four cohorts) in urine samples collected at least once during pregnancy. We operationalized outcomes as PE/E and composite HDP (PE/E and/or gestational hypertension). After correcting phthalate metabolite concentrations for urinary dilution, we evaluated covariate-adjusted associations of individual phthalates with odds of PE/E or composite HDP via generalized estimating equations, and the phthalate mixture via quantile-based g-computation. We also explored effect measure modification by fetal sex using stratified models. Effect estimates are reported as odds ratios (OR) with 95% confidence intervals (95% CIs). ResultsIn adjusted analyses, a doubling of mono-benzyl phthalate (MBzP) and of mono (3-carboxypropyl) phthalate (MCPP) concentrations was associated with higher odds of PE/E as well as composite HDP, with somewhat larger associations for PE/E. For example, a doubling of MCPP was associated with 1.12 times the odds of PE/E (95%CI 1.00, 1.24) and 1.02 times the odds of composite HDP (95%CI 1.00, 1.05). A quartile increase in the phthalate mixture was associated with 1.27 times the odds of PE/E (95%CI 0.94, 1.70). A doubling of mono-carboxy isononyl phthalate (MCiNP) and of mono-carboxy isooctyl phthalate (MCiOP) concentrations were associated with 1.08 (95%CI 1.00, 1.17) and 1.11 (95%CI 1.03, 1.19) times the odds of PE/E. Effect estimates for PE/E were generally larger among pregnancies carrying female fetuses. DiscussionIn this study, multiple phthalates were associated with higher odds of PE/E and HDP. Estimates were precise and some were low in magnitude. Interventions to reduce phthalate exposures during pregnancy may help mitigate risk of these conditions.

Alternative routine for reporting chiral amphetamine test results in assessment of attention-deficit/hyperactivity disorder medication: experiences from 2013 to 2023.

This study evaluated an alternative routine for reporting urinary chiral amphetamine results in assessment of attention-deficit/hyperactivity disorder (ADHD) treatment with amphetamine medications and for detecting side-use of illicit racemic amphetamine. Currently in Sweden, only enantiopure d-amphetamine-based ADHD medications (lisdexamphetamine dimesylate and dexamphetamine sulfate) are approved. It is therefore unsuitable to express the chiral result as the l/d-ratio, as before, because l-amphetamine should not be present provided treatment compliance. A new routine for LC-MS/MS chiral amphetamine testing was therefore introduced in 2020, whereby the relative proportion (%) of l-amphetamine and the total amphetamine and creatinine concentrations are reported. Evaluation of the new routine on 24,354 results from 2013 to 2023 revealed that it was useful to distinguish ADHD medication adherence from illicit drug use as the source for a positive test. The l-amphetamine proportion also reflected the enantiomeric content of the medications used. Overall, most results confirmed adherence to ADHD medication, as the l-amphetamine percentage was <1% in 76% of samples (2023) which is the recommended cutoff with enantiopure d-amphetamine medications. However, in all years, illicit drug use was indicated (>40% l-amphetamine) in 8.3%-14.5% of cases. In conclusion, this study demonstrated the clinical value and utility of a new routine for reporting urinary chiral amphetamine results to differentiate adherence to ADHD medication from illicit drug use. Unlike the l/d-amphetamine ratio, it considers differences in total amphetamine concentration and urine dilution, factors that can affect the interpretation.

Worldwide productivity and research trend of publications concerning SIAD: a bibliometric study.

Syndrome of inappropriate antidiuretic(SIAD) occurs secondary to various diseases, which is characterised by hypotonic hyponatremia and impaired urinary diluting capacity. Research on SIAD in both domestic and international contexts has a long history. This study objectively and comprehensively analyses the research trends, hotspots and development of SIAD research of the past 20 years using the method of bibliometric analysis. The 2003-2022 data in the Web of Science Core Collection database were searched. The Bibliometrix software package, VOSviewer and CiteSpace were used to mine, extract and visualise the retrieved literature, and the generated maps were used in analysing the main topics and trends in the field of SIAD research. A total of 1215 articles published in 623 journals were included in the analysis, with a total of 18,886 citations. Results showed that the research output on SIAD has continuously increased in the past 20 years, and the United States had the highest number of publications and citations. Keywords with the highest burst strength in recent years were the most mentioned keywords, in addition to the search terms 'hyponatremia', 'covid-19', and 'mortality'. Thus, the relationship among SIAD, covid-19 and mortality may become research frontiers and trends. Fifteen milestone articles were identified through co-citation analysis, which mainly focused on the pathophysiology and treatment of SIAD. Based on bibliometric analysis and knowledge mapping, this study summarises development trends in the field of SIAD research, providing references for current and future research into SIAD.

Hyponatremia in the Context of Liver Disease

Hyponatremia in the Context of Liver Disease

Spot urine sodium as a marker of urine dilution and decongestive abilities in acute heart failure

The decongestion ability in response to diuretic treatment plays a crucial role in the treatment of acute heart failure. This effectiveness is evaluated through the assessment of sodium concentration and urine volume, which are also treatment goals themselves. However, the bidirectional interconnection between these factors remains not fully understood. The objective of this study is to provide mechanistic insights into the correlation between spot urine sodium concentrations (UNa+) and urine dilution. This aims to better understand of the decongestive abilities in acute heart failure (AHF). The study was single-center, prospective, conducted on a group of 50 AHF patients. Each participant received a standardized furosemide dose of 1 mg per kg of body weight. Hourly diuresis was measured in the first 6 h of the study, and urine composition was assessed at predefined timepoints. The study group presented the exponential (rather than linear) pattern of relationship between UNa+ and 6-h urine volume, whereas relationship between eGFR and 6-h urine volume was linear (r = 0.61, p < 0.001). The relationship between UNa+ and all other analyzed indices of urine dilution, including the change from baseline in urine creatinine concentration, urine osmolarity, and urine osmolarity corrected for urine sodium, also exhibited an exponential relationship. Patients who were chronically exposed to furosemide demonstrated a significantly lower urine dilution (1.78 [1.18–3.54] vs 11.58 [3.9–17.88]; p < 0.001) in comparison to naïve individuals. In conclusion, it should be noted that in AHF higher UNa+ is associated with disproportionally higher urine dilution, and patients naïve to furosemide have significantly greater ability to dilute urine when compare to chronic furosemide users.

Diabetes Insipidus: Types, Diagnosis and Management

Diabetes insipidus (DI) is an acquired or hereditary water imbalance disorder characterized by polydipsia and polyuria. It is a condition that involves the excretion of dilute urine in large volumes. The illness can strike at any age, with males and females have identical rates of occurrence of the disease. The two main mechanisms responsible for diabetes insipidus are either insufficient release or production of ADH (antidiuretic hormone) from the hypothalamus (central diabetes insipidus) or ADH resistance in which the kidneys are unable to respond to ADH (nephrogenic diabetes insipidus). Another form of DI is transient diabetes insipidus commonly known as gestational diabetes insipidus that occurs in the second/third trimester of pregnancy due to increased levels of placental vasopressinase that occurs progressively during pregnancy and increases metabolic clearance of vasopressin. The fourth type of DI is primary polydipsia, characterized by elevated levels of water intake that physiologically lower vasopressin and may be psychogenic, iatrogenic or dipsogenic. Signs and symptoms of DI often include water electrolyte-imbalance, excessive or severe thirst, frequent and excessive urination, fatigue, dehydration, and weight loss. Diabetes insipidus (DI) should be distinguished from primary polydipsia, and whether it is caused by a central, nephrogenic, or gestational cause. This distinction is critical since incorrect treatment can result in serious repercussions. Diagnosis of DI includes measurement of plasma sodium and osmolality, baseline copeptin, hypertonic saline stimulation and arginine stimulation test. The treatment for DI includes the use of drugs such as desmopressin, thiazide diuretics, indomethacin and amiloride.

Relationship between Human Body Weight and Specific Gravity of Urine

The objective of this study was to compare the relationship between human body weight and specific gravity of urine. Urinalysis test is not a painful procedure and it is used to analyze the abnormalities. The comparison between urine density and water density is done by the help of urine specific gravity. The condition of diabetes insipidus can be reported during concentrated urine causes the thirst and removal of excess amounts of dilute urine. Fresh sample of urine was collected in a container and immediately a dipstick method was applied for a few seconds the stick was dipped to check the color change. Statistical analysis was done by applying the rules of M-Stat by using t-Test for getting results. This project is a questionnaire based study about the specific gravity of urine of patients. Urine samples of the patients were collected and then measured the weight of the patients. Results obtained that there was not any relationship between human body weight and specific gravity of urine. It was concluded that there was no significant relationship observed between human body weight and specific gravity of urine.

Hydrogel: a new material for intravesical drug delivery after bladder cancer surgery.

The standard treatment for non-muscle invasive bladder cancer (NMIBC) is transurethral resection of bladder tumor (TURBT). However, this procedure may miss small lesions or incompletely remove them, resulting in cancer recurrence or progression. As a result, intravesical instillation of chemotherapy or immunotherapy drugs is often used as an adjunctive treatment after TURBT to prevent cancer recurrence. In the traditional method, drugs are instilled into the patient's bladder through a urinary catheter under sterile conditions. However, this treatment exposes the bladder mucosa to the drug directly, leading to potential side effects like chemical cystitis. Furthermore, this treatment has several limitations, including a short drug retention period, susceptibility to urine dilution, low drug permeability, lack of targeted effect, and limited long-term clinical efficacy. Hydrogel, a polymer material with a high-water content, possesses solid elasticity and liquid fluidity, making it compatible with tissues and environmentally friendly. It exhibits great potential in various applications. One emerging use of hydrogels is in intravesical instillation. By employing hydrogels, drug dilution is minimized, and drug absorption, retention, and persistence in the bladder are enhanced due to the mucus-adhesive and flotation properties of hydrogel materials. Furthermore, hydrogels can improve drug permeability and offer targeting capabilities. This article critically examines the current applications and future prospects of hydrogels in the treatment of bladder cancer.

Long-term safety of dietary salt: A 5-year ProspEctive rAndomized bliNded and controlled stUdy in healThy aged cats (PEANUT study).

High-salt diets promote urine dilution and decrease urolithiasis risk. Prospectively evaluate the safety of chronic high dietary salt intake (randomized controlled trial). Twenty research colony neutered, healthy aged cats (11.5 years [10.0-11.6], median [interquartile range]). Healthy cats were randomized to control or high-salt dry diets (sodium: 1.02 ± 0.16 [mean, SD] and 3.26 ± 0.30 g/Mcal metabolizable energy [ME], respectively; chloride: 2.26 ± 0.33 and 5.71 ± 0.28 g/Mcal ME, respectively), fed for up to 60 months. Assessments included CBC, plasma biochemistry, urinalysis, glomerular filtration rate (GFR), blood pressure, renal and cardiac (conventional Doppler and 2-dimensional color tissue Doppler) imaging, annually. Cats that died or were euthanized underwent necropsy. Diet effects over time were evaluated with linear mixed models. Follow-up duration (median [Interquartile range]) was similar between the control (38.7 months [28.6-48.2]) and high-salt group (51.4 months [45.7-59.0]). Diet had no significant effect on changes in GFR, blood pressure, plasma creatinine concentration, end-diastolic left ventricular (LV) wall thicknesses, LV internal diameters, LV systolic function, left atrial size, or systolic and diastolic Doppler variables. One control cat developed hypertension. One high-salt group cat developed persistent azotemia. Serial plasma biochemistry and urine specific gravity suggested early chronic kidney disease in 4 nonazotemic cats (2 per group), consistent with necropsy findings. In healthy aged cats, a commercial veterinary diet containing 3.26 ± 0.30 g/Mcal ME sodium was safe with regard to renal and cardiac function for up to 5 years.

Central Diabetes Insipidus in Children as a Diagnostic Challenge.

Central diabetes insipidus (CDI) is a disorder in the pediatric population resulting from antidiuretic hormone deficiency. The excessive production of dilute urine characterizes it and manifests with polyuria, nocturia, and polydipsia. The diagnostics of CDI is often challenging, especially concerning the underlying condition of the disease. This article highlights the diverse clinical presentation of children with CDI and diagnostic difficulties among patients with polyuria and polydipsia. The article also reviews the etiology, symptoms, diagnostic workup, and management of CDI. We present 4 pediatric patients (aged 3-13.5 years) diagnosed with CDI of different etiology: 1 due to septo-optic dysplasia/optic nerve hypoplasia and 3 due to acquired processes such as Langerhans cell histiocytosis and germ cell tumor in 2 patients. Central diabetes insipidus was the first manifestation of a tumor or granuloma in all presented patients with acquired pathology. The patients sometimes need long-term follow-up to establish the proper final diagnosis.

FRI312 Diplopia And Headache After Treatment With GnRH Agonist

Abstract Disclosure: A.A. Zakkar: None. M. Al Mushref: None. M. Fadanelli: None. Case Report: The Patient is a 46-year-old male with past medical history of hypertension and prostate cancer, currently undergoing treatment with leuprolide acetate injections, who presented to the emergency department with a complaint of worsening headache. He received his second injection 3 days prior to admission and within hours he developed a headache in the frontal area that was continuous and worsening over time, increasing with positional changes of his head. One day after the treatment he developed persistent double vision. The patient reported that he has had worsening vision over the last year and was to see an ophthalmologist but was diagnosed with prostate cancer at the same time so he became more focused on the oncologic care. He also reported poor balance, excessive thirst and increased urination of large volumes of urine every hour with nocturia several times. On exam the vital signs were normal, he was A&amp;Ox4 and in no distress. He had left abducens and oculomotor nerve palsy but an otherwise benign exam. MRI of the brain revealed a sellar mass measuring 2.2 x 1.7 x 2.3 cm consistent with pituitary macroadenoma extending into the suprasellar cistern, compressing the pituitary stalk and the optic chiasm. Patient was evaluated by ophthalmology who noted +2 optic nerve edema of the left eye. Laboratory evaluation revealed low ACTH of 6 pg/mL at 5:30AM along with corresponding cortisol level of only 1.6 mcg/dL. FSH was low and LH undetectable as expected with GnRH agonist therapy. Growth hormone level, IGF-1, l and prolactin levels were all normal. The TSH was 0.50 microunits/mL with a freeT4 of 1.0. Urinalysis revealed dilute urine with specific gravity &amp;lt;1.006. Serum sodium on admission was 137 mmol/L and after overnight fasting was 140 mmol/L. The patient was started on desmopressin 0.1 mg po at bedtime and on intravenous dexamethasone 4 mg q6hrs. He was evaluated by neurosurgery and ENT who recommended trans-sphenoidal resection of the mass. Pathology report of the specimen was consistent with a pituitary adenoma with infarction without hemorrhage. The patient reported an improvement in his left eye vision and lateral rectus palsy. He was transitioned to oral hydrocortisone 20 mg daily and 10 mg every afternoon prior to discharge. On follow up with endocrinology several months later he was found to have persistent adrenal insufficiency and developed central hypothyroidism that required treatment. Conclusion: Patients with an undiagnosed pituitary adenoma are at risk of tumor expansion and mass effect as well as pituitary apoplexy during treatment with GnRH agonists. In our case clinical presentation was consistent with pituitary apoplexy without evidence of pituitary hemorrhage soon after GnRH agonist. A full ophthalmologic exam may be an appropriate screening prior to initiation of such therapy. Presentation: Friday, June 16, 2023

Alteration of the maximal renal water excretion capacity with kidney function and age in human.

The kidney's capability to concentrate and dilute urine is crucial to maintaining body fluid compartments and plasma osmolality. Advanced age and chronic kidney disease (CKD) result in decreased maximal urine concentration. Less is known regarding urine dilution ability. The primary purpose of this study was to determine the relationship between maximal renal water excretion and renal function, age, and gender in humans. This monocentric retrospective study includes patients referred to the Department of Clinical Physiology in Toulouse University Hospital to measure the glomerular filtration rate (mGFR) between April 2013 and February 2018. mGFR was assessed using inulin renal clearance and required ample hydration. We quantified the effects of age, gender and mGFR have on water excretion ability, which was assessed by minimal urinary osmolality (minUosm) and maximal free water clearance (maxCH2O). 666 patients were included (mean age 51 ± 14years, 53% female). Mean mGFR was 82 ± 25mL/min/1.73m2. MinUosm after hydration was higher in patients with renal insufficiency while maxCH2O was markedly lower. Age was also, with a weaker effect, associated with decreased in water excretion, independently of mGFR. MaxCH2O clearance was similar in both genders, whereas minUosm was lower in women, possibly resulting from a lower osmotic load. This study shows a decrease in maximal urinary dilution capacity and free water clearance with CKD and age, without gender difference. These alterations are mild but must be considered when a significant water intake is required or in the case of hyponatremia.

Classifying Hypotonic Hyponatremia by Projected Treatment Effects - A Quantitative 3-Dimensional Framework

The diagnostic algorithms currently used for hypotonic hyponatremia focus primarily on impaired urinary dilution and often neglect the influence of free water intake and solute excretion. We hypothesized that, in each case of hypotonic hyponatremia different pathophysiological mechanisms play a role simultaneously. Using clinical data of the previous observational Co-Med study, we defined each case of hypotonic hyponatremia concurrently in 3 dimensions as follows: (i) high net free water intake (HNFWI), (ii) impaired dilution of the urine (IDU), and (iii) low nonelectrolyte solute excretion (LNESE). For each dimension, a "standard delta sodium" (sdna) was calculated reflecting the expected difference to the serum sodium concentration, that would result from changing a dimension to a specific and equivalent target level. Results from 279 patients were used for this analysis. With target levels of free water intake and urine osmolality at the fifth percentile, and nonelectrolyte solute excretion at the 95th percentile, median (interquartile range) sdna values were 7.1 (4.8-10.2) for HNFWI, 11.8 (7.0-18.6) for IDU and 2.6 (1.6-4.2) mmol/l per 24 hours for LNESE. Sdna results in individual patients were highest with IDU in 68.5%, HNFWI in 30.8% and 0.7% with LNESE. At an sdna-level of at least 4mmol/l per 24 hours, the prevalence of HNFWI was 78.9%, IDU 87.1%, and LNESE 26.5%. 77.5% of patients had 2 or all 3 mechanisms present. Hyponatremia was mostly multifactorial in subgroups according to classic categories of hyponatremia and typical comorbidities as well. Hypotonic hyponatremia can be quantitatively defined by 3 dimensions. Most cases should be considered multifactorial.

Effects of Sample Dilution on Nuclear Magnetic Resonance-Derived Metabolic Profiles of Human Urine.

Traditionally, a relatively big urine volume (e.g., 500 μL) is used in nuclear magnetic resonance (NMR)-based human metabolomics, which is not feasible for studies with limited/precious samples. Although urine may be diluted before conventional high-throughput metabolomics analysis, the comprehensive effect of urine dilution on metabolic profiles is unknown. Here, for the first time, we systematically investigated the effect of urine dilution on 1H NMR metabolic profiles, by evaluating signal detectability, integration, signal-to-noise ratio (SNR), chemical shift (δ) and its variation, and signal overlapping of 47 metabolites in 10 volunteers. We observed significant linear changes along with increased dilution, including decreased integration and SNR, altered δ, decreased intersample variation of δ, and increased separation between overlapped signals, e.g., lactate and threonine, β-d-glucose and an unassigned signal, and histidine and 3-methylhistidine. We further tested the 40% dilution level (i.e., employing 300 μL urine) in an epidemiological study containing 1018 pregnant women from the Tongji-Shuangliu Birth Cohort, showing acceptable detectability and chemical shift variability for most of the 47 metabolites profiled. It indicated that mild (e.g., 40%) dilution of human urine can largely preserve the high-abundance metabolites profiled, reduce intersample chemical shift variations, and increase separations of overlapped signals, which is an improvement of routine sample preparation methods in NMR-based metabolomics and is applicable for studies with limited urine volumes, including large-scale epidemiological studies.

Peptide aptamer-based time-resolved fluoroimmunoassay for CHIKV diagnosis

BackgroundChikungunya virus (CHIKV) and Dengue virus (DENV) have similar clinical symptoms, which often induce misdiagnoses. Therefore, an antigen detection diagnostic system that can clearly identify these two viruses is desirable.MethodsIn this study, we developed a novel peptide with high affinity and specificity to CHIKV, and further constructed peptide aptamer-based TRFIA assay to efficiently detect CHIKV. Peptide aptamer B2 (ITPQSSTTEAEL) and B3 (DTQGSNWI) were obtained through computer-aided design and selected as CHIKV-specific peptide aptamers based on their high binding affinity, strong hydrogen bonding, and RMSD of molecular docking. Then, a sandwich-Time-Resolved Fluoroimmunoassay (TRFIA) was successfully constructed for the detection of the interaction between peptide aptamers and viruses.ResultsWhen using B2 as the detection element, highly specific detection of CHIKV E2 was achieved with detection limits of 8.5 ng/ml in PBS solution. Variation coefficient between inter-assay showed the disturbances received from the detection of clinical fluid specimens (including serum and urine), were also within acceptable limits. The detection limits for 10-fold dilution serum and urine were 57.8 ng/mL and 147.3 ng/mL, respectively. The fluorescent signal intensity exhibited a good linear correlation with E2 protein concentration in the range of 0-1000 ng/mL, indicating the potential for quantitative detection of E2 protein.ConclusionsThese results demonstrate that the construction of peptide aptamers with high affinity and specificity provides an excellent method for rapid diagnostic element screening, and the developed peptide aptamer B2 contributed to better detection of CHIKV viral particles compared to traditional antibodies.

Urinary cadmium and endometriosis prevalence in a US nationally representative sample: results from NHANES 1999-2006.

Is exposure to toxic metal cadmium associated with increased endometriosis prevalence among a nationally representative sample of the US population? Concentrations of urinary cadmium, a long-term biomarker (10-30 years) of cadmium exposure, were associated with an increased prevalence of endometriosis. Cadmium exhibits estrogenic properties and may increase the risk of endometriosis, a gynecologic condition associated with substantial morbidity, for which estrogen has a central pathogenic role. Previous epidemiological studies of cadmium and endometriosis have yielded mixed results, with null, positive, and inverse associations being reported. We conducted a cross-sectional study using data from four cycles of the National Health and Nutrition Examination Survey (NHANES) 1999-2006. The study population comprised participants aged 20-54 years who had an endometriosis diagnosis, available data on urinary cadmium, and a glomerular filtration rate ≥60 ml/min/1.73 m2 (unweighted n = 1647). Urinary cadmium was measured by inductively coupled plasma-mass spectrometry, and we used urinary creatinine concentrations and covariate-adjusted standardization to account for urinary dilution. Self-reported diagnosis of endometriosis was ascertained by interview. We examined the association between quartiles of urinary cadmium and endometriosis using log-binomial regression to estimate adjusted prevalence ratios (aPRs) and 95% CIs. We observed twice the prevalence of endometriosis for participants with cadmium concentrations in the second quartile (versus the first quartile) (aPR 2.0, 95% CI: 1.1, 3.9) and the third quartile (versus the first quartile) (aPR 2.0, 95% CI: 1.1, 3.7). Our data also suggested a 60% increased prevalence of endometriosis with urinary cadmium concentrations in the fourth quartile (versus the first quartile) (aPR 1.6, 95% CI: 0.8, 3.2). In a sensitivity analysis, restricting the study population to premenopausal participants with an intact uterus and at least one ovary (unweighted n = 1298), stronger associations accompanied by wider CIs were observed. We were limited by the ascertainment of urinary cadmium and endometriosis diagnosis at a single time point, given the cross-sectional study design, and we relied on self-report of endometriosis diagnosis. However, urinary cadmium characterizes long-term exposure and findings from validation studies suggest that misclassification of self-reported endometriosis diagnosis may be minimal. This study suggests that cadmium is associated with an increased endometriosis prevalence. Given the substantial morbidity conferred by endometriosis and that the general population is ubiquitously exposed to cadmium, further research is warranted to confirm our findings. This work was supported by the National Institute of Nursing Research (grant R00NR017191 to K.U.) of the National Institutes of Health. The authors report no conflict of interest. N/A.

Exposure to Arsenic and Subclinical Cardiovascular Disease in 9- to 11-Year-Old Children, Syracuse, New York

Studies in adults have demonstrated associations between arsenic exposure and clinical and subclinical cardiovascular disease (CVD). No studies to date have considered potential associations in children. To examine the association between total urinary arsenic levels in children and subclinical indicators of CVD. This cross-sectional study considered 245 children, a subset from the Environmental Exposures and Child Health Outcomes (EECHO) cohort. Children from the Syracuse, New York, metropolitan area were recruited from August 1, 2013, until November 30, 2017, with enrollment throughout the year. Statistical analysis was performed from January 1, 2022, to February 28, 2023. Total urinary arsenic was measured using inductively coupled plasma mass spectrometry. Creatinine concentration was used to adjust for urinary dilution. In addition, potential exposure routes (eg, diet) were measured. Three indicators of subclinical CVD were assessed: carotid-femoral pulse wave velocity, carotid intima media thickness, and echocardiographic measures of cardiac remodeling. The study sample included 245 children aged 9 to 11 years (mean [SD] age, 10.52 [0.93] years; 133 [54.3%] female). The geometric mean of the creatinine-adjusted total arsenic level in the population was 7.76 μg/g creatinine. After adjustment for covariates, elevated total arsenic levels were associated with significantly greater carotid intima media thickness (β = 0.21; 95% CI, 0.08-0.33; P = .001). In addition, echocardiography revealed that elevated total arsenic was significantly higher for children with concentric hypertrophy (indicated by greater left ventricular mass and greater relative wall thickness; geometric mean, 16.77 μg/g creatinine; 95% CI, 9.87-28.79 μg/g) relative to the reference group (geometric mean, 7.39 μg/g creatinine; 95% CI, 6.36-8.58 μg/g). With respect to exposure source, significant geographic clustering of total arsenic was found in 1 urban area of Syracuse, New York. These findings suggest a significant association between arsenic exposure and subclinical CVD in children. Elevated total arsenic levels were found in an area of Syracuse with known elevations of toxic metals from industrial waste, suggesting historical pollution as a possible source. Given the novelty and potential importance of this association, further research is needed to confirm our findings. Any potential effect of urinary arsenic exposure in childhood on actual clinical CVD outcomes in adulthood remains to be determined.