Name: estimation of urinary nanocrystals in humans using calcium fluorophore labeling and nanoparticle tracking analysis
Uploaded: 2021-02-09T15:00:00
Description: Watch this Scientific Journal Video about Estimation of Urinary Nanocrystals in Humans using Calcium Fluorophore Labeling and Nanoparticle Tracking Analysis at JoVE.com

The authors thank all study participants and the UAB CCTS Bionutrition Core and UAB High Resolution Imaging Service Center for their contributions. This work was supported by NIH grants DK106284 and DK123542 (TM), and UL1TR003096 (National Center for Advancing Translational Sciences).

All experiments outlined in this work were approved by the University of Alabama at Birmingham (UAB) Institutional Review Board. Healthy adults (33.6 &#177; 3.3 years old; n=10) were enrolled in the study if they had a normal blood comprehensive metabolic panel, non-tobacco users, non-pregnant, a BMI between 20-30 kg/m2, and free of chronic medical conditions or acute illnesses. Healthy participants signed a written informed consent form prior to the start of the study.
1. Clinical pr...

<ol>
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NTA has been used in the present study to assess nanocrystals in human urine using a calcium binding probe, Fluo-4 AM. There is no standard method available to detect nanocrystals in the urine. Some research groups have detected nanocrystals in the urine and relied on the use of extensive protocols or methods that are limited in their ability to quantify the samples27,28. This study shows a specific and sensitive method for detecting calcium containing nanocrysta...

Urinary crystals form when urine becomes supersaturated with minerals. This can occur in healthy individuals but is more common in individuals with kidney stones1. The presence and accumulation of urinary crystals can increase one&#39;s risk of developing a kidney stone. Specifically, this occurs when crystals bind to Randall&#39;s plaque, nucleate, accumulate, and grow over time2,3,4. Crystalluria precedes kidney stone formation and assessment of crystalluria may have predictive value in kidney stone formers3,5. Specifically, crystalluria has been suggested to be useful to predict the risk of stone recurrence in patients with a history of calcium oxalate containing stones6,7.
Crystals have been reported to negatively impact renal epithelial and circulating immune cell function8,9,10,11,12,13. It has been previously reported that circulating monocytes from calcium oxalate (CaOx) kidney stone formers have suppressed cellular bioenergetics compared to healthy individuals14. In addition, CaOx crystals reduce cellular bioenergetics and disrupt redox homeostasis in monocytes8. Consumption of meals rich in oxalate may cause crystalluria which could lead to renal tubule damage and alter the production and function of urinary macromolecules that are protective against kidney stone formation15,16. Several studies have demonstrated that urinary crystals can vary in shape and size depending on the pH and temperature of the urine17,18,19. Further, urinary proteins have been shown to modulate crystal behavior20. Daudon et al.19, proposed that crystalluria analysis could be helpful in the management of patients with kidney stone disease and in assessing their response to therapies. A few conventional methods currently available to evaluate the presence of crystals include polarized microscopy21,22, electron microscopy23, particle counters3, urine filtration24, evaporation3,5 or centrifugation21. These studies have provided valuable insight to the kidney stone field regarding crystalluria. However, a limitation of these methods has been the inability to visualize and quantify crystals less than 1 &#181;m in size. Crystals of this size may influence the growth of CaOx stones by attaching to Randall&#39;s plaque.
Nanocrystals have been shown to cause extensive injury to renal cells compared to larger microcrystals25. The presence of nanocrystals has been reported in urine using a nanoparticle analyzer26,27. Recent studies have used fluorescently labeled bisphosphate probes (alendronate-fluorescein/alendronate-Cy5) to examine nanocrystals using nanoscale flow cytometry28. The limitation of this dye is that it is not specific and will bind to almost all types of stones except cysteine. Thus, accurately assessing the presence of nanocrystals in individuals may be an effective tool to diagnose crystalluria and/or predict stone risk. The purpose of this study was to detect and quantify calcium containing nanocrystals (&#60;1 &#181;m in size) using nanoparticle tracking analysis (NTA). To achieve this, NTA technology was used in combination with a calcium binding fluorophore, Fluo-4 AM to detect and quantify calcium containing nanocrystals in the urine of healthy adults.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Benchtop Centrifuge</td>
			<td>Jouan Centrifuge</td>
			<td>CR3-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium Oxalate monohydrate</td>
			<td>Synthesized in the lab as previously described29.</td>
			<td> </td>
			<td>Store at RT; Stock 10 mM</td>
		</tr>
		<tr>
			<td>Calcium Phosphate crystals (hydroxyapatite nanopowder)</td>
			<td>Sigma</td>
			<td>677418</td>
			<td>Store at RT; Stock 10 mM</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Fischer Scientific</td>
			<td>AC615095000</td>
			<td>Store at RT; Stock 100%</td>
		</tr>
		<tr>
			<td>Fluo-4 AM*</td>
			<td>AAT Bioquest, Inc.</td>
			<td>20550</td>
			<td>Store at Freezer (-20&#176;C); Stock 5 mM</td>
		</tr>
		<tr>
			<td>Gold Nanoparticles</td>
			<td>Sigma</td>
			<td>742031</td>
			<td>Store at 2-8&#176;C</td>
		</tr>
		<tr>
			<td>NanoSight Instrument</td>
			<td>Malvern Instruments, UK</td>
			<td>NS300</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe pump</td>
			<td>Harvard Apparatus</td>
			<td>98-4730</td>
			<td></td>
		</tr>
		<tr>
			<td>Virkon Disinfectant</td>
			<td>LanXESS Energizing Company, Germany</td>
			<td>LSP</td>
			<td></td>
		</tr>
		<tr>
			<td colspan="4">*Fluorescence dyes are light sensitive; stock and aliquots should be stored in the dark at -20&#176;C.</td>
		</tr>
	</tbody>
</table>

estimation of urinary nanocrystals in humans using calcium fluorophore labeling and nanoparticle tracking analysis

Kidney stones are becoming more prevalent worldwide in adults and children. The most common type of kidney stone is comprised of calcium oxalate (CaOx) crystals. Crystalluria occurs when urine becomes supersaturated with minerals (e.g., calcium, oxalate, phosphate) and precedes kidney stone formation. Standard methods to assess crystalluria in stone formers include microscopy, filtration, and centrifugation. However, these methods primarily detect microcrystals and not nanocrystals. Nanocrystals have been suggested to be more harmful to kidney epithelial cells than microcrystals in vitro. Here, we describe the ability of Nanoparticle Tracking analysis (NTA) to detect human urinary nanocrystals. Healthy adults were fed a controlled oxalate diet prior to drinking an oxalate load to stimulate urinary nanocrystals. Urine was collected for 24 hours before and after the oxalate load. Samples were processed and washed with ethanol to purify samples. Urinary nanocrystals were stained with the calcium binding fluorophore, Fluo-4 AM. After staining, the size and count of nanocrystals were determined using NTA. The findings from this study show NTA can efficiently detect nanocrystalluria in healthy adults. These findings suggest NTA could be a valuable early detection method of nanocrystalluria in patients with kidney stone disease.

The findings from this study show NTA can efficiently detect the mean size and concentration of calcium containing urinary nanocrystals in human urine. This was achieved by using the fluorophore, Fluo-4 AM, and nanoparticle tracking analysis. Fluo-4 AM was able to bind to both CaOx and CaP crystals. As shown in Figure 3A, CaOx crystals were determined to be between 50-270 nm in size and have a mean concentration of 1.26 x 109 particles/mL. CaP crystals were between 30-225 nm in si...

Watch this Scientific Journal Video about Estimation of Urinary Nanocrystals in Humans using Calcium Fluorophore Labeling and Nanoparticle Tracking Analysis at JoVE.com

Estimation of Urinary Nanocrystals in Humans using Calcium Fluorophore Labeling and Nanoparticle Tracking Analysis

The objective of this study was to determine whether nanoparticle tracking analysis (NTA) could detect and quantify urinary calcium containing nanocrystals from healthy adults. The findings from the current study suggest NTA could be a potential tool to estimate urinary nanocrystals during kidney stone disease.

Kidney stones are becoming more prevalent worldwide in adults and children. The most common type of kidney stone is comprised of calcium oxalate (CaOx) ...

This protocol can specifically detect calcium-containing nanocrystals in human urine. This technique could potentially be useful to predict early stages of kidney stone formation as well as other diseases associated with crystal urea. Demonstrating the procedure will be Dr.Parveen Kumar, a researcher IV in my laboratory.Have participants consume a low-oxalate diet for three days and fast overnight. Then collect a 24-hour urine sample from the participants before having them consume an oxalate load. Feed the participants with a smoothie containing fruits and vegetables having an oxalate load of approximately eight millimoles.Have participants collect their urine for 24 hours post-oxalate consumption and return it on the following day. Maintain all urine samples at room temperature prior to processing. Measure and record urine pH and volume of the urine samples.Mix thoroughly and add 50 milliliters of urine into a labeled sterile 50 milliliter conical tube. Centrifuge the sample at 1, 200 times G for 10 minutes at room temperature using a bench-top centrifuge. Discard the supernatant, then wash and resuspend the pellet again with five milliliters of 100%ethanol.Centrifuge the sample at 1, 200 times G for 10 minutes at room temperature using a bench-top centrifuge. Discard the supernatant and resuspend the pellet in one milliliter of 100%ethanol. Store the sample at minus 20 degrees Celsius for later processing or immediately proceed with staining the samples.Dilute 100 nanometer-sized gold nanoparticles in ultrapure water at a ratio of 1:1, 000 and use them for optimizing the settings on the instrument. Dilute the urine samples 20 times in water prior to staining with five millimolar Fluo-4 AM for 30 minutes in the dark and analyze the samples using NTA. Prepare calcium oxalate and calcium phosphate crystals as described in the text manuscript prior to NTA analysis.Turn on the computer and the instrument, then open the software and turn on the camera. Click the capture icon in the top left corner of the window to start the capture mode. Clean the platform by first pumping air into it using a one milliliter syringe until the platform appears clean.Gently add water to the apparatus two to three times and use another one milliliter syringe to remove any air bubbles. Once the platform is clean, add water and check for any contamination on the surface by viewing the camera, then add gold nanoparticles as a control to the sample loading pump injector to set up the instrument. Adjust the camera level on the screen or on the knob to the right side of the instrument until the image starts to display colored pixels, then reduce the camera level.Next, adjust the screen to optimize the image. Left click the mouse button on the video image. Hold the left mouse button and drag the image up and down to get the entire view.Set up the infusion speed and focus the camera so that the gold nanoparticles are visible on the camera screen. Set the infusion speed to high for initial setup to ensure the gold nanoparticles are detected. Once detected, reduce the speed to 50 microliters per minute to visualize gold nanoparticles.Adjust the camera level to visualize the particles. For unstained samples, adjust the screen gain at level five to achieve the camera focus and set the camera level at eight. Once the focus is set, record the sample.After optimization, clean the apparatus again with water before assessing other samples to ensure that the tubing is clean and particles are not present. To analyze stained samples, adjust the camera to the filter position containing the suitable fluorescent filter and load diluted and stained samples onto the sample loading pump injector, reducing the speed to 20 microliters per minute for analysis. Adjust the screen gain to five and camera level to 13.Save the data after each measurement. Calculate the average number of nanoparticles for all five readings for each individual sample and analyze the data using standard deviation or standard error of the mean. Use T-tests for paired analysis.Fluo-4 AM was able to bind to both calcium oxalate crystals, which were between 50 and 270 nanometers in size and had a mean concentration of 1, 260 million particles per milliliter, and calcium phosphate crystals, which were between 30 and 225 nanometers and had a mean concentration of 2, 220 million particles per milliliter. 24-hour urine samples collected before the oxalate load contained some urinary nanocrystals between 110 to 300 nanometers in size. In contrast, there was a significant increase in urinary nanocrystals present in post-oxalate samples.To confirm the reproducibility of the method, samples were measured three times and there was no significant variation in technical replicates. When attempting this protocol, there may be some difficulty with adding samples without bubbles to the machine. To prevent this, add air and water to the machine, and then slowly add samples.Also, make sure to continually monitor your samples and that there are no bubbles present. This new method will be tested in individuals with calcium oxalate kidney stone disease to monitor disease progression and/or to predict kidney stone risk.

estimation-urinary-nanocrystals-humans-using-calcium-fluorophore

Research

JoVE Journal

Medicine

Evaluation of Nanoparticle Uptake in Tumors in Real Time Using Intravital Imaging

Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle uptake in tumors at the microscopic level1,2,3, highlighting the utility of a suitable xenograft model in which to perform detailed uptake analyses. Here, we use high-resolution intravital imaging to evaluate nanoparticle uptake in human tumor xenografts in a modified, shell-less chicken embryo model. The chicken embryo model is particularly well-suited for these in vivo analyses because it supports the growth of human tumors, is relatively inexpensive and does not require anesthetization or surgery 4,5. Tumor cells form fully vascularized xenografts within 7 days when implanted into the chorioallantoic membrane (CAM) 6. The resulting tumors are visualized by non-invasive real-time, high-resolution imaging that can be maintained for up to 72 hours with little impact on either the host or tumor systems. Nanoparticles with a wide range of sizes and formulations administered distal to the tumor can be visualized and quantified as they flow through the bloodstream, extravasate from leaky tumor vasculature, and accumulate at the tumor site. We describe here the analysis of nanoparticles derived from Cowpea mosaic virus (CPMV) decorated with near-infrared fluorescent dyes and/or polyethylene glycol polymers (PEG) 7, 8, 9,10,11. Upon intravenous administration, these viral nanoparticles are rapidly internalized by endothelial cells, resulting in global labeling of the vasculature both outside and within the tumor7,12. PEGylation of the viral nanoparticles increases their plasma half-life, extends their time in the circulation, and ultimately enhances their accumulation in tumors via the enhanced permeability and retention (EPR) effect 7, 10,11. The rate and extent of accumulation of nanoparticles in a tumor is measured over time using image analysis software. This technique provides a method to both visualize and quantify nanoparticle dynamics in human tumors.

We present a novel approach to quantify nanoparticle localization in the vasculature of human xenografted tumors using dynamic, real-time intravital imaging in an avian embryo model.

Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle ...

Labeling Stem Cells with Ferumoxytol, an FDA-Approved Iron Oxide Nanoparticle

Stem cell based therapies offer significant potential for the field of regenerative medicine. However, much remains to be understood regarding the in vivo kinetics of transplanted cells. A non-invasive method to repetitively monitor transplanted stem cells in vivo would allow investigators to directly monitor stem cell transplants and identify successful or unsuccessful engraftment outcomes.
A wide range of stem cells continues to be investigated for countless applications. This protocol focuses on 3 different stem cell populations: human embryonic kidney 293 (HEK293) cells, human mesenchymal stem cells (hMSC) and induced pluripotent stem (iPS) cells. HEK 293 cells are derived from human embryonic kidney cells grown in culture with sheared adenovirus 5 DNA. These cells are widely used in research because they are easily cultured, grow quickly and are easily transfected. hMSCs are found in adult marrow. These cells can be replicated as undifferentiated cells while maintaining multipotency or the potential to differentiate into a limited number of cell fates. hMSCs can differentiate to lineages of mesenchymal tissues, including osteoblasts, adipocytes, chondrocytes, tendon, muscle, and marrow stroma. iPS cells are genetically reprogrammed adult cells that have been modified to express genes and factors similar to defining properties of embryonic stem cells. These cells are pluripotent meaning they have the capacity to differentiate into all cell lineages 1. Both hMSCs and iPS cells have demonstrated tissue regenerative capacity in-vivo.
Magnetic resonance (MR) imaging together with the use of superparamagnetic iron oxide (SPIO) nanoparticle cell labels have proven effective for in vivo tracking of stem cells due to the near microscopic anatomical resolution, a longer blood half-life that permits longitudinal imaging and the high sensitivity for cell detection provided by MR imaging of SPIO nanoparticles 2-4. In addition, MR imaging with the use of SPIOs is clinically translatable. SPIOs are composed of an iron oxide core with a dextran, carboxydextran or starch surface coat that serves to contain the bioreactive iron core from plasma components. These agents create local magnetic field inhomogeneities that lead to a decreased signal on T2-weighted MR images 5. Unfortunately, SPIOs are no longer being manufactured. Second generation, ultrasmall SPIOs (USPIO), however, offer a viable alternative. Ferumoxytol (FerahemeTM) is one USPIO composed of a non-stoichiometric magnetite core surrounded by a polyglucose sorbitol carboxymethylether coat. The colloidal, particle size of ferumoxytol is 17-30 nm as determined by light scattering. The molecular weight is 750 kDa, and the relaxivity constant at 2T MRI field is 58.609 mM-1 sec-1 strength4. Ferumoxytol was recently FDA-approved as an iron supplement for treatment of iron deficiency in patients with renal failure 6. Our group has applied this agent in an &ldquo;off label&rdquo; use for cell labeling applications. Our technique demonstrates efficient labeling of stem cells with ferumoxytol that leads to significant MR signal effects of labeled cells on MR images. This technique may be applied for non-invasive monitoring of stem cell therapies in pre-clinical and clinical settings.

We describe a technique for labeling and tracking stem cells with FDA-approved, superparamagnetic iron oxide (SPIO), ferumoxytol (Feraheme). This cellular imaging technique that utilizes magnetic resonance (MR) imaging for visualization, is readily accessible for long-term monitoring and diagnosis of successful or unsuccessful stem cell engraftments in patients.

Stem cell based therapies offer significant potential for the field of regenerative medicine. However, much remains to be understood regarding the in vivo ...

In vivo 19F MRI for Cell Tracking

In vivo 19F MRI allows quantitative cell tracking without the use of ionizing radiation. It is a noninvasive technique that can be applied to humans. Here, we describe a general protocol for cell labeling, imaging, and image processing. The technique is applicable to various cell types and animal models, although here we focus on a typical mouse model for tracking murine immune cells. The most important issues for cell labeling are described, as these are relevant to all models. Similarly, key imaging parameters are listed, although the details will vary depending on the MRI system and the individual setup. Finally, we include an image processing protocol for quantification. Variations for this, and other parts of the protocol, are assessed in the Discussion section. Based on the detailed procedure described here, the user will need to adapt the protocol for each specific cell type, cell label, animal model, and imaging setup. Note that the protocol can also be adapted for human use, as long as clinical restrictions are met.

In vivo 19F MRI for Cell Tracking

We describe a general protocol for in vivo cell tracking using MRI in a mouse model with ex vivo labeled cells. A typical protocol for cell labeling, image acquisition processing and quantification is included.

In vivo 19F MRI allows quantitative cell tracking without the use of ionizing radiation. It is a noninvasive technique that can be applied to humans. ...

Induction and Assessment of Exertional Skeletal Muscle Damage in Humans

Contraction-induced muscle damage via voluntary eccentric (lengthening) contractions offers an excellent model for studying muscle adaptation and recovery in humans. Herein we discuss the design of an eccentric exercise protocol to induce damage in the quadriceps muscles, marked by changes in strength, soreness, and plasma creatine kinase levels. This method is simple, ethical, and widely applicable since it is performed in human participants and eliminates the interspecies translation of the results. Subjects perform 300 maximal eccentric contractions of the knee extensor muscles at a speed of 120&#176;/sec on an isokinetic dynamometer. The extent of the damage is measurable using relatively non-invasive isokinetic and isometric measures of strength loss, soreness, and plasma creatine kinase levels over several days following the exercise. Therefore, its application can be directed to specific populations in an attempt to identify mechanisms for muscle adaptation and regeneration.

This article describes a safe and reliable method to induce and quantify exertional skeletal muscle damage in human subjects.

Contraction-induced muscle damage via voluntary eccentric (lengthening) contractions offers an excellent model for studying muscle adaptation and recovery ...

A Model to Simulate Clinically Relevant Hypoxia in Humans

In case of apnea, arterial partial pressure of oxygen (pO2) decreases, while partial pressure of carbon dioxide (pCO2) increases. To avoid damage to hypoxia sensitive organs such as the brain, compensatory circulatory mechanisms help to maintain an adequate oxygen supply. This is mainly achieved by increased cerebral blood flow. Intermittent hypoxia is a commonly seen phenomenon in patients with obstructive sleep apnea. Acute airway obstruction can also result in hypoxia and hypercapnia. Until now, no adequate model has been established to simulate these dynamics in humans. Previous investigations focusing on human hypoxia used inhaled hypoxic gas mixtures. However, the resulting hypoxia was combined with hyperventilation and is therefore more representative of high altitude environments than of apnea. Furthermore, the transferability of previously performed animal experiments to humans is limited and the pathophysiological background of apnea induced physiological changes is poorly understood. In this study, healthy human apneic divers were utilized to mimic clinically relevant hypoxia and hypercapnia during apnea. Additionally, pulse-oximetry and Near Infrared Spectroscopy (NIRS) were used to evaluate changes in cerebral and peripheral oxygen saturation before, during, and after apnea.

Hypoxia simulation in humans has usually been performed by inhaling hypoxic gas mixtures. For this study, apneic divers were used to simulate dynamic hypoxia in humans. Additionally, physiological changes in desaturation and re-saturation kinetics were evaluated with non-invasive tools such as Near-Infrared-Spectroscopy (NIRS) and peripheral oxygenation saturation (SpO2).

In case of apnea, arterial partial pressure of oxygen (pO2) decreases, while partial pressure of carbon dioxide (pCO2) increases. To avoid damage to ...

In Vivo Tracking of Edema Development and Microvascular Pathology in a Model of Experimental Cerebral Malaria Using Magnetic Resonance Imaging

Cerebral malaria is a sign of severe malarial disease and is often a harbinger of death. While aggressive management can be life-saving, the detection of cerebral malaria can be difficult. We present an experimental mouse model of cerebral malaria that shares multiple features of the human disease, including edema and microvascular pathology. Using magnetic resonance imaging (MRI), we can detect and track the blood-brain barrier disruption, edema development, and subsequent brain swelling. We describe multiple MRI techniques that can visualize these pertinent pathological changes. Thus, we show that MRI represents a valuable tool to visualize and track pathological changes, such as edema, brain swelling, and microvascular pathology, in vivo.

In Vivo Tracking of Edema Development and Microvascular Pathology in a Model of Experimental Cerebral Malaria Using Magnetic Resonance Imaging

We describe a mouse model of experimental cerebral malaria and show how inflammatory and microvascular pathology can be tracked in vivo using magnetic resonance imaging.

Cerebral malaria is a sign of severe malarial disease and is often a harbinger of death. While aggressive management can be life-saving, the detection of ...

Comparing Bibliometric Analysis Using PubMed, Scopus, and Web of Science Databases

Literature databases (i.e., PubMed, Scopus, and Web of Science) differ in terms of their coverage, focus, and the tool they provide. PubMed focuses mainly on life sciences and biomedical disciplines, whereas Scopus and Web of Science are multidisciplinary. The protocol described in the current study was used to search for publications from Jordanian authors in the years 2013-2017. In this protocol, how to use each database to conduct this type of search is explained in detail. A Scopus search resulted in the highest number of documents (11,444 documents), followed by a Web of Science search (10,943 documents). PubMed resulted in a smaller number of documents due to its narrower scope and coverage (4,363 documents). The results also show a yearly trend in: (1) the number of publications, (2) the disciplines that have the most publications, (3) the countries of collaboration, and (4) the number of open access publications. In contrast, PubMed has a sophisticated keyword optimization service (i.e., Medical Subject Heading, or MeSH), while both Scopus and Web of Science provide search analysis tools that can produce representative figures. Finally, the features of each database are explained in detail and several indices that can be extracted using the search results are provided. This study provides a base for using literature databases for bibliometric analysis.

Literature databases are commonly used to assess publications in a certain subject, discipline, country, or region of the world, a practice known as bibliometric analysis. The current protocol details how to use PubMed, Scopus, and Web of Science databases to do bibliometric analysis.

Literature databases (i.e., PubMed, Scopus, and Web of Science) differ in terms of their coverage, focus, and the tool they provide. PubMed focuses mainly ...

Estimation of Nephron Number in Whole Kidney using the Acid Maceration Method

Nephron endowment refers to the total number of nephrons an individual is born with, as nephrogenesis in humans is completed by 36 weeks of gestation and no new nephrons are formed post-birth. Nephron number refers to the total number of nephrons measured at any point in time post-birth. Both genetic and environmental factors influence both nephron endowment and number. Understanding how specific genes or factors influence the process of nephrogenesis and nephron loss or demise is important as individuals with lower nephron endowment or number are thought to be at a higher risk of developing renal or cardiovascular disease. Understanding how environmental exposures over the course of a person's lifetime affects nephron number will also be vital in determining future disease risk. Thus, the ability to assess whole kidney nephron number quickly and reliably is a basic experimental requirement to better understand mechanisms that contribute to or promote nephrogenesis or nephron loss. Here, we describe the acid maceration method for the estimation of whole kidney nephron number based on the procedure described by Damadian, Shawayri, and Bricker, with slight modifications. The acid maceration method provides fast and reliable estimates of nephron number (as assessed by counting glomeruli) that are within 5% of those determined using more advanced, albeit expensive, methods such as magnetic resonance imaging. Moreover, the acid maceration method is an excellent high-throughput method to assess nephron number in large numbers of samples or experimental conditions.

Estimates of whole kidney nephron number are important clinically and experimentally, as there is an inverse association between nephron number and an enhanced risk of renal and cardiovascular disease.Herein, the use of the acid maceration method, which provides fast and reliable estimates of whole kidney nephron number, is demonstrated.

Nephron endowment refers to the total number of nephrons an individual is born with, as nephrogenesis in humans is completed by 36 weeks of gestation and ...

Ultrasonography of the Adult Male Urinary Tract for Urinary Functional Testing

The incidence of clinical benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) is increasing due to the aging population, resulting in a significant economic and quality of life burden. Transgenic and other mouse models have been developed to recreate various aspects of this multifactorial disease; however, methods to accurately quantitate urinary dysfunction and the effectiveness of new therapeutic options are lacking. Here, we describe a method that can be used to measure bladder volume and detrusor wall thickness, urinary velocity, void volume and void duration, and urethral diameter. This would allow for the evaluation of disease progression and treatment efficacy over time. Mice were anesthetized with isoflurane, and the bladder was visualized by ultrasound. For non-contrast imaging, a 3D image was taken of the bladder to calculate volume and evaluate shape; the bladder wall thickness was measured from this image. For contrast-enhanced imaging, a catheter was placed through the dome of the bladder using a 27-gauge needle connected to a syringe by PE50 tubing. A bolus of 0.5 mL of contrast was infused into the bladder until a urination event occurred. Urethral diameter was determined at the point of the Doppler velocity sample window during the first voiding event. Velocity was measured for each subsequent event yielding a flow rate. In conclusion, high frequency ultrasound proved to be an effective method for assessing bladder and urethral measurements during urinary function in mice. This technique may be useful in the assessment of novel therapies for BPH/LUTS in an experimental setting.

We describe the use of high frequency ultrasound with contrast imaging as a method to measure bladder volume, bladder wall thickness, urine velocity, void volume, void duration, and urethral diameter. This strategy can be used to assess voiding dysfunction and treatment efficacy in various mouse models of lower urinary tract dysfunction (LUTD).

The incidence of clinical benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) is increasing due to the aging population, resulting ...

On-Site Sampling and Extraction of Brain Tumors for Metabolomics and Lipidomics Analysis

Despite the variety of tools available for cancer diagnosis and classification, methods that enable fast and simple characterization of tumors are still in need. In recent years, mass spectrometry has become a method of choice for untargeted profiling of discriminatory compound as potential biomarkers of a disease. Biofluids are generally considered as preferable matrices given their accessibility and easier sample processing while direct tissue profiling provides more selective information about a given cancer. Preparation of tissues for the analysis via traditional methods is much more complex and time-consuming, and, therefore, not suitable for fast on-site analysis. The current work presents a protocol combining sample preparation and extraction of small molecules on-site, immediately after tumor resection. The sampling device, which is of the size of an acupuncture needle, can be inserted directly into the tissue and then transported to the nearby laboratory for instrumental analysis. The results of metabolomics and lipidomics analyses demonstrate the capability of the approach for the establishment of phenotypes of tumors related to the histological origin of the tumor, malignancy, and genetic mutations, as well as for the selection of discriminating compounds or potential biomarkers. The non-destructive nature of the technique permits subsequent performance of routinely used tests e.g., histological tests, on the same samples used for SPME analysis, thus enabling attainment of more comprehensive information to support personalized diagnostics.

The manuscript presents on-site sampling of human brain tumors with solid phase microextraction followed by their biochemical profiling towards the discovery of biomarkers.

Despite the variety of tools available for cancer diagnosis and classification, methods that enable fast and simple characterization of tumors are still ...