Smartphone paired SIM card-type integrated creatinine biosensor

Medical diagnostic sector is relying on affordable, handheld devices integrating smart biosensing and transducing interfaces that enable clinical analysis with minimal end-user intervention and resource requirements. In response, we propose here, a SIM card-type pH responsive polymer-modified paper-based biosensing device, coupled to a smartphone, for the determination of urinary creatinine. A vertical microfluidic channel was fabricated on a paper strip by wax printing. The hydrophilic area was coated by a poly(methylmethacrylate)/poly(methacrylic acid) random copolymer, PMMA-co-PMAA, and on top of it, creatinine deiminase (CD) was immobilized. Data demonstrated, on the one hand, zero vertical flow of urine through the enzyme-free PMMA-co-PMAA-modified paper strip, i.e., a high selectivity against the components of the matrix, and on the other hand, in the presence of CD, a creatinine -concentration dependent commence of sample's downward flow due to the selective, creatinine-triggered degradation of the copolymer by the enzymatically produced ammonia. This CD/PMMA-co-PMAA paper-based biosensing smart assembly is coupled with three conductive strips, which enable the automatic on/off (sample addition/measurement end) measurement of the copolymer degradation time, through electric resistance measurements. It also features an in-built sample well and wireless communication support through the integration of a Bluetooth® microprocessor incorporated with time and resistance measuring circuits. Using newly synthesized pH responsive PMMA-co-PMAA at different molecular weights and volume fraction ratios offering tunable dissolution properties, the detection range was adjusted over 3-30 mM creatinine to overspread the normal range of creatinine in urine. The device was successfully applied to the determination of urinary creatinine.

Preliminary Evidence for Cannabis and Nicotine Urinary Metabolites as Predictors of Verbal Memory Performance and Learning Among Young Adults

OBJECTIVE

Verbal memory deficits are linked to cannabis use. However, self-reported episodic use does not allow for assessment of variance from other factors (e.g., cannabis potency, route of consumption) that are important for assessing brain-behavior relationships. Further, co-occurring nicotine use may moderate the influence of cannabis on cognition. Here we utilized objective urinary measurements to assess the relationship between metabolites of cannabis, 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THCCOOH), and nicotine (cotinine) on verbal memory in young adults.

METHOD

Adolescents and young adults (n = 103) aged 16-22 completed urinary drug testing and verbal memory assessment (RAVLT). Linear regressions examined the influence of THCCOOH and cotinine quantitative concentrations, and their interaction, on RAVLT scores, controlling for demographics and alcohol. Cannabis intake frequency was also investigated. Secondary analyses examined whether past month or recency of use related to performance, while controlling for THCCOOH and cotinine concentrations.

RESULTS

THCCOOH concentration related to both poorer total learning and long delay recall. Cotinine concentration related to poorer short delay recall. Higher frequency cannabis use status was associated with poorer initial learning and poorer short delay. When comparing to self-report, THCCOOH and cotinine concentrations were negatively related to learning and memory performance, while self-report was not.

CONCLUSIONS

Results confirm the negative relationship between verbal memory and cannabis use, extending findings with objective urinary THCCOOH, and cotinine concentration measurements. No moderating relationship with nicotine was found, though cotinine concentration independently associated with negative short delay performance. Findings support the use of both urinary and self-report metrics as complementary methods in substance use research.

Diaper-embedded urine test device for the screening of urinary tract infections in children: a cohort study

BACKGROUND

There is a need for an easy and sensitive method for screening of urinary tract infections in young children. We set out to test whether a novel diaper-embedded urine test device is feasible and reliable in screening for urinary tract infections.

METHODS

This prospective cohort study consisted of young children examined due to a suspected acute urinary tract infection at the Pediatric Emergency Department of the Oulu University Hospital, Finland. We analyzed the same urine samples using three different methods: 1) a diaper-embedded test device applied to the urine pad within the diaper, 2) a urine sample aspirated from the urine pad for the conventional point-of-care dipstick test, and 3) a urine sample aspirated from the urine pad and analyzed in the laboratory with an automated urine chemistry analyzer. The gold standard for confirming urinary tract infection was quantitative bacterial culture.

RESULTS

Urine samples were available from 565 children. Bacterial culture confirmed urinary tract infection in 143 children. Sensitivity of the positive leukocyte screening of the diaper-embedded urine test device was 93.1% (95% CI: 87.4-96.8) and that of the point-of-care urine dipstick analysis was 95.4% (90.3-98.3) in those with both tests results available (n = 528). The sensitivity of the positive leukocyte test of the diaper-embedded test device was 91.4% (85.4-95.5) and that of the automated analysis was 88.5% (82.0-93.3) in those with both tests available (n = 547). The time to the test result after urination was immediate for the diaper-embedded test, 1-5 min for point-of-care dipstick, and 30-60 min for laboratory-based automated urine chemistry analyzer.

CONCLUSIONS

In this prospective study, the diaper-embedded urine test device was an easy and sensitive screening method for UTIs in young children. The main clinical benefit of the diaper-embedded urine test device was that the screening test result was available immediately after urination.

Detection of allopurinol and oxypurinol in canine urine by HPLC/MS-MS: Focus on veterinary clinical pharmacokinetics

Allopurinol is the most commonly used drug for the treatment of hyperuricemia in people, and in view of the risks of fatal hypersensitivity in patients with renal dysfunction, doses based on the glomerular filtration rate are proposed. In veterinary medicine, allopurinol is used in the treatment of canine leishmaniasis (CanL) caused by Leishmania infantum owing to the drug action of inhibiting the parasite's RNA synthesis. However, renal dysfunction frequently ensues from disease progression in dogs. The purpose of the present study was to standardize and validate a sensitive high-performance liquid chromatography-mass spectrometric (HPLC-MS/MS) method to determine the concentration of allopurinol and its active metabolite oxypurinol in canine urine for clinical pharmacokinetic investigation. Urine samples of eleven (11) dogs with naturally occurring CanL and in the maintenance phase of the treatment with alopurinol were used. For the chromatographic analysis of urine, the mobile phase consisted of a solution of 0.1 % formic acid (88 %) in 10 mM ammonium acetate. Separation of allopurinol and oxypurinol occurred in a flow of 0.8 mL/min on a C8 reverse phase column 5 μm, and acyclovir was the internal standard. The HPLC-MS/MS method was validated by reaching the limits of detection and quantification, reproducibility and linearity. The lower limit of quantification achieved by the method was 10 μg/mL for both allopurinol and oxypurinol. Calibration curves were prepared in blank urine added with allopurinol at concentrations of 10-1000 μg/mL, and oxypurinol at 10-200 μg/mL. Coefficients of variation of less than 15 % between intracurrent and intercurrent accuracy values were observed for both allopurinol and oxypurinol. Urine test samples remained stable after being subjected to freeze-thaw cycles and remaining at room temperature for 4 h. The method proved to be adequate to quantify allopurinol and oxypurinol in urine samples from dogs under treatment.