Human fluorescent profile of urine as a simple tool of mining in data from autofluorescence spectroscopy

Influence of vitamins and food on the fluorescence spectrum of human urine

OBJECTIVES

Fluorescence spectroscopy of human urine is a method with the potential to gain importance as a diagnostic tool in the medical field, e.g., for measuring Coproporphyrin III (CPIII) as an indicator of cancer and acute types of porphyria. Food can change human urine's color, which could influence the urine fluorescence spectrum and the detection of CPIII in urine. To determine if there is a noticeable influence on the urine fluorescence spectrum or on the detection of CPIII in urine, 16 vitamin supplements, and three food items were tested. Such investigation may also prevent false interpretation of measured data.

METHODS

Urine samples were collected before and after (overnight, ca. 8 h) intake of each test substance. Samples were investigated by fluorescence spectrum analysis. At excitation wavelengths from 300 to 500 nm and emission wavelengths from 400 to 700 nm excitation-emission-matrices were measured. Data obtained from urine before intake were compared to the data from overnight urine. Furthermore, the investigation of any interference with the CPIII concentration was performed at an excitation wavelength of 407 ± 3 nm and emission wavelengths of 490-800 nm.

RESULTS

Only vitamin B2, but none of the other tested substances, showed noticeable influence on the urine fluorescence spectrum. None of the tested substances showed noticeable interference with the recovery rate of CPIII.

CONCLUSIONS

The correct interpretation of measured data by fluorescence spectroscopy is possible with the exception if vitamin B2 supplementation was performed; thus, the consumption of vitamin B2 supplements before fluorescence testing of the patient's urine should be avoided and/or must be requested. CPIII concentrations could reliably be measured in all cases.

Isolation-free measurement of single urinary extracellular vesicles by imaging flow cytometry

Urinary extracellular vesicles (uEVs) are promising biomarkers for various diseases. However, many tools measuring uEVs rely on time-consuming uEV isolation methods, which could induce sample bias. This study demonstrates the detection of single uEVs without isolation using imaging flow cytometry (IFCM). Unstained urine samples contained auto-fluorescent (A-F) particles when characterized with IFCM. Centrifugation successfully removed A-F particles from the unprocessed urine. Based on the disappearance of A-F particles, a gate was defined to distinguish uEVs from A-F particles. The final readouts of IFCM were verified as single EVs based on detergent treatment and serial dilutions. When developing this protocol to measure urine samples with abnormally high protein levels, 25 mg/mL dithiothreitol (DTT) showed improved uEV recovery over 200 mg/mL DTT. This study provides an isolation-free protocol using IFCM to quantify and phenotype single uEVs, eliminating the hindrance and influence of A-F particles, protein aggregates, and coincidence events.

Urine fluorescence spectroscopy combined with machine learning for screening of hepatocellular carcinoma and liver cirrhosis

In this paper, we investigated the possibility of using urine fluorescence spectroscopy and machine learning method to identify hepatocellular carcinoma (HCC) and liver cirrhosis from healthy people. Urine fluorescence spectra of HCC (n = 62), liver cirrhosis (n = 65) and normal people (n = 60) were recorded at 405 nm excitation using a Fluorescent scan multimode reader. The normalized fluorescence spectra revealed endogenous metabolites differences associated with the disease, mainly the abnormal metabolism of porphyrin derivatives and bilirubin in the urine of patients with HCC and liver cirrhosis compared to normal people. The Support vector machine (SVM) algorithm was used to differentiate the urine fluorescence spectra of the HCC, liver cirrhosis and normal groups, and its overall diagnostic accuracy was 83.42%, the sensitivity for HCC and liver cirrhosis were 93.55% and 73.85%, and the specificity for HCC and liver cirrhosis were 88.00% and 89.34%, respectively. This exploratory work shown that the combination of urine fluorescence spectroscopy and SVM algorithm has great potential for the noninvasive screening of HCC and liver cirrhosis.

Derivative Three-Dimensional Synchronous Fluorescence Analysis of Tear Fluid and Their Processing for the Diagnosis of Glaucoma

Background: Sensitive and rapid diagnosis of the early stages of glaucoma from tear fluid is a great challenge for researchers. Methods: Tear fluid was analyzed using three-dimensional synchronous fluorescence spectroscopy (3D-SFS). Our previously published results briefly describe the main methods which applied the second derivative to a selected synchronous spectrum Δλ = 110 nm in distinguishing between healthy subjects (CTRL) and patients with glaucoma (POAG). Results: In this paper, a novel strategy was used to evaluate three-dimensional spectra from the tear fluid database of our patients. A series of synchronous excitation spectra were processed as a front view and presented as a single curve showcasing the overall fluorescence profile of the tear fluid. The second derivative spectrum provides two parameters that can enhance the distinction between CTRL and POAG tear fluid. Conclusions: Combining different types of 3D-SFS data can offer interesting and useful diagnostic tools and it can be used as input for machine learning and process automation.

A dual-caged resorufin probe for rapid screening of infections resistant to lactam antibiotics

The alarming increase of antimicrobial resistance urges rapid diagnosis and pathogen specific infection management. This work reports a rapid screening assay for pathogenic bacteria resistant to lactam antibiotics. We designed a fluorogenic N-cephalosporin caged 3,7-diesterphenoxazine probe CDA that requires sequential activations to become fluorescent resorufin. A series of studies with recombinant β-lactamases and clinically prevalent pathogens including Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens demonstrated that CDA possessed superior sensitivity in reporting the activity of β-lactamases including cephalosporinases and carbapenemases. After a simple filtration, lactam-resistant bacteria in urine samples could be detected at 103 colony-forming units per milliliter within 2 hours.

[Association of neonatal blood calcium levels with perinatal factors and neonatal urinary calcium levels measured by an intelligent urine test system]

OBJECTIVE

To study the association of neonatal blood calcium levels with perinatal factors and neonatal urinary calcium levels measured by an intelligent urine test system.

METHODS

The medical data of 96 full-term singleton neonates with mild diseases were collected by a cross-sectional survey, who were hospitalized in the Department of Neonatology, The First Affiliated Hospital of Xi'an Jiaotong University, from June to August 2018. Urinary calcium levels measured by an intelligent urine test system, total blood calcium levels, ionized calcium levels, and the mother's calcium and vitamin D supplementation during pregnancy were recorded.

RESULTS

Compared with the group without vitamin D supplementation for the mother (17 neonates), the group with vitamin D supplementation for the mother (79 neonates) had significantly higher levels of total blood calcium and ionized calcium (P < 0.05).The group with both vitamin D and calcium supplementation for the mother (68 neonates) had significantly higher levels of ionized calcium than controls (28 neonate) (P=0.05). There was no significant difference in the levels of total blood calcium and ionized calcium between the group with calcium supplementation for the mother (74 neonates) and the group without calcium supplementation for the mother (22 neonates) (P > 0.05). The hypothermia group (5 neonates) had a significantly lower level of total blood calcium than the normal body temperature group (91 neonates) (P < 0.05). There was a significantly positive correlation between the maternal blood total calcium level and the neonatal blood total calcium and ionized calcium levels (r=0.881 and 0.703 respectively; P < 0.05). The neonatal urinary calcium level measured by the intelligent urine test system was significantly correlated with the blood ionized calcium level (r=0.526, P=0.025).

CONCLUSIONS

Vitamin D supplementation during pregnancy can increase the blood levels of total calcium and ionized calcium in neonates, and calcium supplementation alone cannot increase the blood levels of total calcium or ionized calcium in neonates. Hypothermia in neonates might cause the reduction in blood calcium levels. The urinary calcium level measured by the intelligent urine test system is positively correlated with the blood level of ionized calcium.

Strong Dependence between Tryptophan-Related Fluorescence of Urine and Malignant Melanoma

Urine autofluorescence at 295 nm is significantly higher in patients with malignant melanoma at each clinical stage compared to the healthy group. The largest difference is in the early-stages and without metastases. With increasing stage, the autofluorescence at 295 nm decreases. There is also a significant negative correlation between autofluorescence and Clark classification. Based on our results, it is assumed that the way malignant melanoma grows also affects urinary autofluorescence.