The work was supported by grants from Sigrid Juselius Foundation (SP, MP), Finnish Cultural Foundation (AA, MH), Academy of Finland (SP, MP), Orion Farmos Foundation (MH), Tampere Tuberculosis Foundation (SP, MH and MP) and Jane and Aatos Erkko Foundation (SP and MP). We thank our Italian and French collaborators, Prof. Supuran, and Prof. Winum, for providing carbonic anhydrase inhibitors for safety and toxicity evaluation for anti-TB and anti-cancer drug development purposes. We thank Aulikki Lehmus and Marianne Kuuslahti for the technical assistance. We also thank Leena M&#228;kinen and Hannaleena Piippo for their help with the zebrafish breeding and collection of embryos. We sincerely thank Harlan Barker for critical evaluation of the manuscript and insightful comments.

The zebrafish core facility at Tampere University has an establishment authorization granted by the National Animal Experiment Board (ESAVI/7975/04.10.05/2016). All the experiments using zebrafish embryos were performed according to the Provincial Government of Eastern Finland, Social and Health Department of Tampere Regional Service Unit protocol # LSLH-2007-7254/Ym-23.
1. Setting Up of Overnight Zebrafish Mating Tanks
<ol>
	<li>Place 2-5 adult male zebrafish and 3-5 adult female zebrafish into mating tanks overnight. (Breeding is induced in the morning by automatic dark and light cycle overnight).</li>
	<li>Set up several crosses to obtain enough embryos for assessing the toxicity of more than two chemical compounds. For the evaluation of toxicity, each concentration needs a minimum of 20 embryos23.</li>
	<li>To avoid handling stress to the animals, allow the animals to rest for 2 weeks before using the same individuals for breeding.</li>
</ol>
2. Collection of Embryos and Preparing Plates for Exposure to the Chemical Compounds
<ol>
	<li>Collect the embryos, the next day before noon, using a fine-mesh strainer and transfer them onto a Petri dish containing E3 embryo medium [5.0 mM NaCl, 0.17 mM KCl, 0.33 mM CaCl2, 0.33 mM MgSO4, and 0.1% w/v Methylene Blue].</li>
	<li>Remove debris using a plastic Pasteur pipette (e.g., food and solid waste). Examine each batch of embryos under the stereomicroscope to remove the unfertilized/dead embryos (identified by their opaque appearance).</li>
	<li>Keep the embryos at 28.5 &#176;C in an incubator. Examine the embryos, the next morning, under a stereomicroscope and remove any unhealthy or dead embryos. Also, replace the old E3 medium with fresh E3 medium. 
	NOTE:&#160;Zebrafish embryos are always maintained at 28.5 &#176;C under laboratory conditions.&#160;</li>
	<li>Carefully transfer 1 embryo into each well of a 24-well plate containing enough E3 medium to cover the embryos.</li>
</ol>
3. Preparations of the Stock Solution of Chemical Compounds and Distribution of Diluted Compound into the Wells
<ol>
	<li>Take out the vials containing inhibitor compounds stored at 4 &#176;C. 
	NOTE: Depending on the properties of the compound, these are stored at different temperatures.</li>
	<li>Weigh the compound(s) using an analytical balance that can weigh a few milligrams (mg) of the compound accurately.</li>
	<li>Prepare at least 250 &#956;L (100 mM) of stock solution for each compound in an appropriate solvent (e.g., E3 water or Dimethyl sulfoxide (DMSO), based on the solubility properties of the compounds. 
	NOTE: The above steps can be done a day before the start of the experiment at a convenient time and stored at 4 &#176;C).</li>
	<li>Make serial dilutions of the stock solutions (e. g., 10 &#956;M, 20 &#956;M, 50 &#956;M, 100 &#956;M, 150 &#956;M, 300 &#956;M and 500 &#956;M) using E3 water in 15 mL centrifuge tubes. 
	NOTE: The concentrations and number of serial dilutions vary from one compound to another compound depending on their toxicity levels.</li>
	<li>From the 24 well plate containing embryos, remove E3 water from the wells using a Pasteur pipette and a 1 mL pipette (containing 1 dpf embryos) one row at a time.</li>
	<li>Distribute 1 mL of each diluent in each well (starting from lower and moving to higher concentration) into the wells of 24-well plate.</li>
	<li>Set up a control group from the same batch of embryos and add the corresponding amount of diluent.</li>
	<li>Label 24-well plates with the name and concentration of the compound and keep the plates at 28.5 &#176;C in an incubator.</li>
</ol>
4. Phenotypic Analysis and Imaging of the Embryos Using a Stereomicroscope
<ol>
	<li>Examine the embryos under a stereomicroscope for parameters 24 h after exposure to the chemical compounds.
	<ol>
		<li>Note the parameters such as mortality, hatching, heartbeat, utilization of yolk sack, swim bladder development, movement of the fish, pericardial edema, and shape of the body23.</li>
		<li>Take the larvae exposed to each concentration of the compound and lay them sideways in a small Petri dish containing 3% high molecular weight methyl cellulose using a metal probe. 
		NOTE: The 3% methyl cellulose (high molecular with) is a viscous liquid needed for embedding the fish with a required orientation for microscopic examination. For orienting the fish in this liquid, a metal probe is needed.</li>
		<li>Take the images using stereomicroscope attached to a camera. Save the images in a separate folder each day till the end of the experiment.</li>
		<li>Enter all the observations in a table each day either in an online table or on a printed sheet.</li>
		<li>If the compounds are neurotoxic, the 4 to 5 dpf larvae may show altered swim pattern, make a record of such changes either by capturing a short (30 s to 1 min) video of the larvae exhibiting abnormal movement pattern.</li>
		<li>After 5 days of exposure to the chemical compounds, note the concentration at which half of the embryos die for calculating the half maximal lethal concentration 50 (LC50) of each chemical. 
		NOTE: The LC50 is the concentration at which 50% of the embryos die at the end of 5 days of exposure to a chemical compound. Use a minimum of 20 embryos for testing the toxicity of each concentration of a compound23.</li>
		<li>Construct a curve for mortality of embryos for all the concentrations using a suitable program.</li>
	</ol>
	</li>
</ol>

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No potential conflict of interest was reported by the authors.

In vitro toxicity test using cultured cells can detect survival and morphological studies of the cells providing limited information about the toxicity induced by the test compound. The advantage of toxicity screening of chemical compounds using zebrafish embryos is rapid detection of chemically induced phenotypic changes in a whole animal during embryonic development in a relevant model organism. Approximately 70% of protein-coding human genes have orthologs counterparts in the zebrafish genome<sup class="xref"...

Drug development is an expensive process. Before a single chemical compound is approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) several thousand compounds are screened at a cost of over one billion dollars1. During the preclinical development, the largest part of this cost is required for the animal testing2. To limit the costs, researchers in the field of drug development need alternative models for the safety screening of chemical compounds3. Therefore, in the early phase of the drug development, it would be very beneficial to use a method that can rapidly evaluate the safety and toxicity of the compounds in a suitable model. There are several protocols that have been used for the toxicity screening of chemical compounds involving animal and cell culture models but there is not a single protocol that is validated and is in common use4,5. Existing protocols using zebrafish vary in length and have been used by individual researchers who evaluated the toxicity as per their convenience requirement6,7,8,9,10,11,12.
In the recent past, the zebrafish has emerged as a convenient model for the evaluation of the toxicity of chemical compounds during embryonic development6,7. The zebrafish has many in-built advantages for the evaluation of chemical compounds13. Even large-scale experiments are amenable, as a zebrafish female can lay batches of 200-300 eggs, which develop rapidly ex&#160;vivo, do not need external feeding for up to a week and are transparent. The compounds can be added directly into the water, where they can (depending on the nature of the compound) diffuse through the chorion, and after hatching, through the skin, gills and mouth of larvae. The experiments do not require copious amounts of chemical compounds14 due to the small size of the embryo. Developing zebrafish embryos express most of the proteins required to achieve the normal developmental outcome. Therefore, a zebrafish embryo is a sensitive model to assess whether a potential drug can disturb the function of a protein or signaling molecule that is developmentally significant. The organs of the zebrafish become functional between 2-5 dpf15, and compounds that are toxic during this sensitive period of embryonic development induce phenotypic defects in zebrafish larvae. These phenotypic changes can be readily detected using a simple microscope without invasive techniques11. Zebrafish embryos are widely used in toxicological research due to their much greater biological complexity compared to in vitro drug screening using cell culture models16,17. &#160;As a vertebrate, the genetic and physiologic makeup of zebrafish is comparable to humans and hence toxicities of chemical compounds are similar between zebrafish and humans8,18,19,20,21,22. Zebrafish is, thus, a valuable tool in the early phase of drug discovery for the evaluation of toxicity and safety of the chemical compounds.
In the present article, we provide a detailed description of the method used for evaluating the safety and toxicity of carbonic anhydrase (CA) inhibitor compounds using 1-5-day post fertilization (dpf) zebrafish embryos by a single researcher. The protocol involves exposing zebrafish embryos to different concentrations of chemical inhibitor compounds and studying the mortality and phenotypic changes during the embryonic development. At the end of the exposure to the chemical compounds, the LC50 dose of the chemical is determined. The method allows an individual to carry out efficient screening of 1-5 test compounds and takes about 8-10 h depending on the experience of the person with the method (Figure 1). Each of the steps required to assess the toxicity of the compounds is outlined in Figure 2. The evaluation of toxicity of CA inhibitors requires 8 days, and includes setting up of mating pairs (day 1); collection of embryos from breeding tanks, cleaning and transferring them to 28.5 &#176;C incubator (day 2); distribution of the embryos into the wells of a 24-well plate and addition of diluted CA inhibitor compounds (day 3); phenotypic analysis and imaging of larvae (day 4-8), and determination of LC50 dose (day8). &#160;This method is rapid and efficient, requires a small amount of the chemical compound and only basic facilities of the laboratory.

<table border="0" cellpadding="0" cellspacing="0" style="width:972px;" width="972">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">24-well plates</td>
			<td style="width:185px;">Nunc</td>
			<td style="width:260px;">Thermo Scientific</td>
			<td style="width:185px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Balance (Weighing scale)</td>
			<td style="width:185px;">KERN</td>
			<td style="width:260px;">PLJ3000-2CM</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Balance (Weighing scale)</td>
			<td style="width:185px;">Mettler Toledo</td>
			<td style="width:260px;">AB104-S/PH</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">CaCl2</td>
			<td style="width:185px;">JT.Baker</td>
			<td style="width:260px;">RS421910024</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Disecting Probe</td>
			<td style="width:185px;">Thermo Scientific</td>
			<td>17-467-604&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">DMSO</td>
			<td style="width:185px;">Sigma Aldrich, Germany</td>
			<td style="width:260px;">D4540</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Falcon tubes 15 mL</td>
			<td style="width:185px;">Greiner bio-one</td>
			<td style="width:260px;">188271</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">High molecular weight methylcellulose</td>
			<td style="width:185px;">Sigma Aldrich, Germany</td>
			<td style="width:260px;">M0262&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Incubator for zebrafish larvae</td>
			<td style="width:185px;">Termaks</td>
			<td style="width:260px;">B8000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">KCL</td>
			<td style="width:185px;">Merck</td>
			<td style="width:260px;">1.04936.0500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Methyl Blue</td>
			<td style="width:185px;">Sigma Aldrich, Germany</td>
			<td style="width:260px;">28983-56-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">MgSO4</td>
			<td style="width:185px;">Sigma Aldrich, Germany</td>
			<td style="width:260px;">M7506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Microcentrifuge tubes</td>
			<td style="width:185px;">Starlab</td>
			<td style="width:260px;">S1615-5500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">NaCl</td>
			<td style="width:185px;">VWR Chemicals</td>
			<td style="width:260px;">27810.295</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Paraffin Histoplast IM</td>
			<td style="width:185px;">Thermo Scientific</td>
			<td style="width:260px;">8331</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Pasteur pipette&#160;</td>
			<td style="width:185px;">Sarstedt</td>
			<td style="width:260px;">86.1171</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Petri dish</td>
			<td style="width:185px;">Thermo Scientific</td>
			<td>101R20&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Petri plates</td>
			<td style="width:185px;">Sarstedt</td>
			<td style="width:260px;">82.1473</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Pipette (1 mL and 200 &#956;L)</td>
			<td style="width:185px;">Thermo Scientific</td>
			<td style="width:260px;">4641230N, 4641210N&#160;&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Plates 24-Well</td>
			<td style="width:185px;">Thermo Scientific</td>
			<td style="width:260px;">142485</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Steriomicroscope/Camera</td>
			<td style="width:185px;">Zeiss</td>
			<td style="width:260px;">Stemi 2000-C/Axiocam 105 color</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Vials (1.5 mL)</td>
			<td style="width:185px;">Fisherbrand</td>
			<td style="width:260px;">11569914</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:342px;">Zebrafish AB strains</td>
			<td style="width:185px;">ZIRC&#160;</td>
			<td style="width:260px;">&#160; ZL1&#160;</td>
			<td></td>
		</tr>
	</tbody>
</table>

rapid evaluation of toxicity of chemical compounds using zebrafish embryos

The zebrafish is a widely used vertebrate model organism for the disease and phenotype-based drug discovery. The zebrafish generates many offspring, has transparent embryos and rapid external development. Zebrafish embryos can, therefore, also be used for the rapid evaluation of toxicity of the drugs that are precious and available in small quantities. In the present article, a method for the efficient screening of the toxicity of chemical compounds using 1-5-day post fertilization embryos is described. The embryos are monitored by stereomicroscope to investigate the phenotypic defects caused by the exposure to different concentrations of compounds. Half-maximal lethal concentrations (LC50) of the compounds are also determined. The present study required 3-6 mg of an inhibitor compound, and the whole experiment takes about 8-10 h to be completed by an individual in a laboratory having basic facilities. The current protocol is suitable for testing any compound to identify intolerable toxic or off-target effects of the compound in the early phase of drug discovery and to detect subtle toxic effects that may be missed in the cell culture or other animal models. The method reduces procedural delays and costs of drug development.

The critical part of the evaluation of toxicity is testing different concentrations of one or multiple chemical compounds in a single experiment. In the beginning, select the compounds for evaluation of toxicity, the number of concentrations to test for each compound, and accordingly, make a chart (Figure 3). We used a unique color for each compound to organize the samples (Figure 3). The use of solvent resistant marker and label...

Watch this Scientific Journal Video about Rapid Evaluation of Toxicity of Chemical Compounds Using Zebrafish Embryos at JoVE.com

Rapid Evaluation of Toxicity of Chemical Compounds Using Zebrafish Embryos

Zebrafish embryos are used for evaluating the toxicity of chemical compounds. They develop externally and are sensitive to chemicals, allowing detection of subtle phenotypic changes. The experiment only requires a small amount of compound, which is directly added to the plate containing embryos, making the testing system efficient and cost-effective.

The zebrafish is a widely used vertebrate model organism for the disease and phenotype-based drug discovery. The zebrafish generates many offspring, has ...

rapid-evaluation-toxicity-chemical-compounds-using-zebrafish

Research

JoVE Journal

Medicine

10.5K Views.  Tampere University. Zebrafish embryos are used for evaluating the toxicity of chemical compounds. They develop externally and are sensitive to chemicals, allowing detection of subtle phenotypic changes. The experiment only requires a small amount of compound, which is directly added to the plate containing embryos, making the testing system efficient and cost-effective.

Video: Rapid Evaluation of Toxicity of Chemical Compounds Using Zebrafish Embryos

Induction of Myocardial Infarction in Adult Zebrafish Using Cryoinjury

The mammalian heart is incapable of significant regeneration following an acute injury such as myocardial infarction1. By contrast, urodele amphibians and teleost fish retain a remarkable capacity for cardiac regeneration with little or no scarring throughout life2,3. It is not known why only some non-mammalian vertebrates can recreate a complete organ from remnant tissues4,5. To understand the molecular and cellular differences between regenerative responses in different species, we need to use similar approaches for inducing acute injuries.
In mammals, the most frequently used model to study cardiac repair has been acute ischemia after a ligation of the coronary artery or tissue destruction after cryoinjury6,7. The cardiac regeneration in newts and zebrafish has been predominantly studied after a partial resection of the ventricular apex2,3. Recently, several groups have established the cryoinjury technique in adult zebrafish8-10. This method has a great potential because it allows a comparative discussion of the results obtained from the mammalian and non-mammalian species.
Here, we present a method to induce a reproducible disc-shaped infarct of the zebrafish ventricle by cryoinjury. This injury model is based on rapid freezing-thawing tissue, which results in massive cell death of about 20% of cardiomyocytes of the ventricular wall. First, a small incision was made through the chest with iridectomy scissors to access the heart. The ventricular wall was directly frozen by applying for 23-25 seconds a stainless steel cryoprobe precooled in liquid nitrogen. To stop the freezing of the heart, fish water at room temperature was dropped on the tip of the cryoprobe. The procedure is well tolerated by animals, with a survival rate of 95%.
To characterize the regenerative process, the hearts were collected and fixed at different days after cryoinjury. Subsequently, the specimen were embedded for cryosectioning. The slides with sections were processed for histological analysis, in situ hybridization and immunofluorescence. This undertaking enhances our understanding of the factors that are required for the regenerative plasticity in the zebrafish, and provide new insights into the machinery of cardiac regeneration. A conceptual and molecular understanding of heart regeneration in zebrafish will impact both developmental biology and regenerative medicine.

Zebrafish represents a valuable model to study the mechanisms of heart regeneration in vertebrates. Here, we present a protocol for induction of a heart infarct in adult zebrafish using cryoinjury. This method results in massive cell death within 20% of the ventricular wall, similar to that observed in mammalian infarcts.

The mammalian heart is incapable of significant regeneration following an acute injury such as myocardial infarction1. By contrast, urodele amphibians and ...

Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS

The calcineurin inhibitor tacrolimus is the cornerstone of most immunosuppressive treatment protocols after solid organ transplantation in the United States. Tacrolimus is a narrow therapeutic index drug and as such requires therapeutic drug monitoring and dose adjustment based on its whole blood trough concentrations. To facilitate home therapeutic drug and adherence monitoring, the collection of dried blood spots is an attractive concept. After a finger stick, the patient collects a blood drop on filter paper at home. After the blood is dried, it is mailed to the analytical laboratory where tacrolimus is quantified using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in combination with a simple manual protein precipitation step and online column extraction.
For tacrolimus analysis, a 6-mm disc is punched from the saturated center of the blood spot. The blood spot is homogenized using a bullet blender and then proteins are precipitated with methanol/0.2 M ZnSO4 containing the internal standard D2,13C-tacrolimus. After vortexing and centrifugation, 100 &#181;l of supernatant is injected into an online extraction column and washed with 5 ml/min of 0.1 formic acid/acetonitrile (7:3, v:v) for 1 min. Hereafter, the switching valve is activated and the analytes are back-flushed onto the analytical column (and separated using a 0.1% formic acid/acetonitrile gradient). Tacrolimus is quantified in the positive multi reaction mode (MRM) using a tandem mass spectrometer.
The assay is linear from 1 to 50 ng/ml. Inter-assay variability (3.6%-6.1%) and accuracy (91.7%-101.6%) as assessed over 20 days meet acceptance criteria. Average extraction recovery is 95.5%. There are no relevant carry-over, matrix interferences and matrix effects. Tacrolimus is stable in dried blood spots at RT and at +4 &#176;C for 1 week. Extracted samples in the autosampler are stable at +4 &#176;C for at least 72 hr.

Here we describe a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay to quantify the immunosuppressant tacrolimus in dried blood spots using a simple manual protein precipitation step and online column extraction.

The calcineurin inhibitor tacrolimus is the cornerstone of most immunosuppressive treatment protocols after solid organ transplantation in the United ...

Diffuse Optical Spectroscopy for the Quantitative Assessment of Acute Ionizing Radiation Induced Skin Toxicity Using a Mouse Model

Acute skin toxicities from ionizing radiation (IR) are a common side effect from therapeutic courses of external beam radiation therapy (RT) and negatively impact patient quality of life and long term survival. Advances in the understanding of the biological pathways associated with normal tissue toxicities have allowed for the development of interventional drugs, however, current response studies are limited by a lack of quantitative metrics for assessing the severity of skin reactions. Here we present a diffuse optical spectroscopic (DOS) approach that provides quantitative optical biomarkers of skin response to radiation. We describe the instrumentation design of the DOS system as well as the inversion algorithm for extracting the optical parameters. Finally, to demonstrate clinical utility, we present representative data from a pre-clinical mouse model of radiation induced erythema and compare the results with a commonly employed visual scoring. The described DOS method offers an objective, high through-put evaluation of skin toxicity via functional response that is translatable to the clinical setting.

We present a diffuse optical spectroscopic (DOS) approach that provides quantitative optical biomarkers of skin response to radiation. We describe DOS instrumentation design, optical parameters extraction algorithms and the animal handling procedures required to yield representative data from a pre-clinical mouse model of radiation induced erythema.

Acute skin toxicities from ionizing radiation (IR) are a common side effect from therapeutic courses of external beam radiation therapy (RT) and ...

Solubility of Hydrophobic Compounds in Aqueous Solution Using Combinations of Self-assembling Peptide and Amino Acid

Self-assembling peptides (SAPs) are promising vehicles for the delivery of hydrophobic therapeutics for clinical applications; their amphipathic properties allow them to dissolve hydrophobic compounds in the aqueous environment of the human body. However, self-assembling peptide solutions have poor blood compatibility (e.g., low osmolarity), hindering their clinical application through intravenous administrations. We have recently developed a generalized platform for hydrophobic drug delivery, which combines SAPs with amino acid solutions (SAP-AA) to enhance drug solubility and increase formulation osmolarity to reach the requirements for clinical uses. This formulation strategy was thoroughly tested in the context of three structurally different hydrophobic compounds &#8211; PP2, rottlerin, and curcumin &#8211; in order to demonstrate its versatility. Furthermore, we examined effects of changing formulation components by analyzing 6 different SAPs, 20 naturally existing amino acids at low and high concentrations, and two different co-solvents dimethyl sulfoxide (DMSO) and ethanol. Our strategy proved to be effective in optimizing components for a given hydrophobic drug, and therapeutic function of the formulated inhibitor, PP2, was observed both in vitro and in vivo. This manuscript outlines our generalized formulation method using SAP-AA combinations for hydrophobic compounds, and analysis of solubility as a first step towards potential use of these formulations in more functional studies. We include representative solubility results for formulation of the hydrophobic compound, curcumin, and discuss how our methodology serves as a platform for future biological studies and disease models.

This protocol describes a clinically-applicable means of dissolving hydrophobic compounds in an aqueous environment using combinations of self-assembling peptide and amino acid solutions. Our method resolves a major limitation of hydrophobic therapeutics, which lack safe, efficient means of solubility and delivery methods into clinical settings.

Self-assembling peptides (SAPs) are promising vehicles for the delivery of hydrophobic therapeutics for clinical applications; their amphipathic ...

Using a Chemical Biopsy for Graft Quality Assessment

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated with an increased survival rate and greater quality of patient&#8217;s life when compared to conventional dialysis. Regrettably, transplantology suffers from a lack of reliable methods for organ quality assessment. Standard diagnostic techniques are limited to macroscopic appearance inspection or invasive tissue biopsy, which do not provide comprehensive information about the graft. The proposed protocol aims to introduce solid phase microextraction (SPME) as an ideal analytical method for comprehensive metabolomics and lipidomic analysis of all low molecular compounds present in kidneys allocated for transplantation. The small size of the SPME probe enables performance of a chemical biopsy, which enables extraction of metabolites directly from the organ without any tissue collection. The minimum invasiveness of the method permits execution of multiple analyses over time: directly after organ harvesting, during its preservation, and immediately after revascularization at the recipient&#8217;s body. It is hypothesized that the combination of this novel sampling method with a high-resolution mass spectrometer will allow for discrimination of a set of characteristic compounds that could serve as biological markers of graft quality and indicators of possible development of organ dysfunction.

The protocol presents utilization of the chemical biopsy approach followed by comprehensive metabolomic and lipidomic analysis for quality assessment of kidney grafts allocated for transplantation.

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated ...

Repetitive Blood Sampling from the Subclavian Vein of Conscious Rat

Rats are widely used in pharmacokinetics (PK) and toxicokinetic (TK) studies that need to collect a certain amount of blood at specific time points to detect drug exposure. The rat blood sampling method determines the quality of the plasma and further affects the precision of the test results. The subclavian vein blood collection method described in this protocol collects blood samples repeatedly in the conscious state of animals to meet the needs of PK and TK tests. The skills of restraint handling and appropriate procedure of needle incision ensure the success rate of blood collection. It is easy to operate while ensuring the quality of plasma and at the same time catering to animal welfare. However, this method requires skilled operation, and an improper one may cause animal weakness, pain, lameness, and even mortality. The current method has been used in the testing facility for a 4-week oral toxicity study in Sprague Dawley (SD) rats with TK. The maximum amount of blood collected within 24 h did not exceed 20% of the animal's total blood. The animals' body weight was more than 200 g for males and females. The data showed that the animals' bodyweight increased steadily every week, and the clinical observation was normal after repetitive sample collection.

The present protocol describes a simple and efficient method for collecting blood from the subclavian vein in rats. It enables rapid, timely, and easily identifiable sampling without anesthesia and obtains high-quality blood through repetitive sample collection.

Rats are widely used in pharmacokinetics (PK) and toxicokinetic (TK) studies that need to collect a certain amount of blood at specific time points to ...

Rapid Viscoelastic Characterization of Airway Mucus Using a Benchtop Rheometer

In muco-obstructive lung diseases (e.g., asthma, chronic obstructive pulmonary disease, cystic fibrosis) and other respiratory conditions (e.g., viral/bacterial infections), mucus biophysical properties are altered by goblet cell hypersecretion, airway dehydration, oxidative stress, and the presence of extracellular DNA. Previous studies showed that sputum viscoelasticity correlated with pulmonary function and that treatments affecting sputum rheology (e.g., mucolytics) can result in remarkable clinical benefits. In general, rheological measurements of non-Newtonian fluids employ elaborate, time-consuming approaches (e.g., parallel/cone-plate rheometers and/or microbead particle tracking) that require extensive training to perform the assay and interpret the data. This study tested the reliability, reproducibility, and sensitivity of Rheomuco, a user-friendly benchtop device that is designed to perform rapid measurements using dynamic oscillation with a shear-strain sweep to provide linear viscoelastic moduli (G&#39;, G&#34;, G*, and tan &#948;) and gel point characteristics (&#947;c&#160;and &#963;c) for clinical samples within 5 min. Device performance was validated using different concentrations of a mucus simulant, 8 MDa polyethylene oxide (PEO), and against traditional bulk rheology measurements. A clinical isolate harvested from an intubated patient with status asthmaticus (SA) was then assessed in triplicate measurements and the coefficient of variation between measurements is &#60;10%. Ex vivo use of a potent mucus reducing agent, TCEP, on SA mucus resulted in a five-fold decrease in elastic modulus and a change toward a more &#34;liquid-like&#34; behavior overall (e.g., higher tan &#948;). Together, these results demonstrate that the tested benchtop rheometer can make reliable measures of mucus viscoelasticity in clinical and research settings. In summary, the described protocol could be used to explore the effects of mucoactive drugs (e.g., rhDNase, N-acetyl cysteine) onsite to adapt treatment on a case-by-case basis, or in preclinical studies of novel compounds.

The viscoelastic properties of mucus play a critical role in mucociliary clearance. However, traditional mucus rheological techniques require complex and time-consuming approaches. This study provides a detailed protocol for the use of a benchtop rheometer that can rapidly and reliably perform viscoelastic measurements.

In muco-obstructive lung diseases (e.g., asthma, chronic obstructive pulmonary disease, cystic fibrosis) and other respiratory conditions (e.g., ...

Analysis of Raw and Processed Cyperi Rhizoma Samples Using Liquid Chromatography-Tandem Mass Spectrometry in Rats with Primary Dysmenorrhea

Cyperi rhizoma (CR) is widely used in gynecology and is a general medicine for treating women's diseases in China. Since the analgesic effect of CR is enhanced after processing with vinegar, CR processed with vinegar (CRV) is generally used clinically. However, the mechanism by which the analgesic effect is enhanced by vinegar processing is unclear. In this study, the ultra-high pressure liquid chromatographytandem mass spectrometry (UPLC-MS/MS) technique was used to examine changes in the blood levels of the exogenous constituents and metabolites between CR-treated and CRV-treated rats with dysmenorrhea. The results revealed differing levels of 15 constituents and two metabolites in the blood of these rats. Among them, the levels of (-)-myrtenol and [(1R,2S,3R,4R)-3-hydroxy-1,4,7,7-tetramethylbicyclo[2.2.1]hept-2-yl]acetic acid in the CRV group were considerably higher than in the CR group. CRV reduced the level of 2-series prostanoids and 4-series leukotrienes with proinflammatory, platelet aggregation, and vasoconstriction activities and provided analgesic effects by modulating arachidonic acid and linoleic acid metabolism and the biosynthesis of unsaturated fatty acids. This study revealed that vinegar processing enhances the analgesic effect of CR and contributes to our understanding of the mechanism of action of CRV.

Here, a comparative analysis of raw and processed Cyperi rhizoma (CR) samples is presented using ultra-high performance liquid chromatography-high-resolution tandem mass spectrometry (UPLC-MS/MS) in rats with primary dysmenorrhea. The changes in blood levels of the metabolites and the sample constituents were examined between rats treated with CR and CR processed with vinegar (CRV).

Cyperi rhizoma (CR) is widely used in gynecology and is a general medicine for treating women's diseases in China. Since the analgesic effect of CR is ...

Enhancing Pulmonary Infection Treatment Using M-ROSE

Microbiological Rapid On-Site Evaluation for Pulmonary Infectious Diseases

The prompt initiation of empirical anti-infective therapy is crucial in patients presenting with unexplained pulmonary infection. Although imaging acquisition is relatively straightforward in clinical practice, its lack of specificity often necessitates additional time-consuming tests such as sputum culture, bronchoalveolar-lavage fluid culture, or genetic sequencing to identify the underlying etiology of the disease accurately. Moreover, the limited efficacy of empirical anti-infective treatment may contribute to antibiotic misuse. Recent advancements in interpreting microbial background on rapid on-site evaluation (ROSE) slides have enabled clinicians to promptly obtain samples through bronchoscopy (e.g., alveolar lavage, mucosal brushing, tissue clamp), facilitating bedside staining and interpretation that provides essential microbial background information. Consequently, this establishes a foundation for developing targeted anti-infection treatment and individualized drug therapy plans. With a better understanding of which pathogens are causing infections in real-time, physicians can avoid unnecessary broad-spectrum antibiotics contributing to antibiotic resistance. Establishing a rapid and standardized M-ROSE workflow within respiratory medicine departments or intensive care units will greatly assist physicians in formulating accurate treatment strategies for patients, which holds significant clinical implications.

Author Spotlight: Advancing Pathogen Detection and Disease Assessment in Real-Time Using M-ROSE

The protocol here demonstrates a fast and standardized microbiological rapid on-site evaluation (M-ROSE) workflow, including three steps: slide making, staining, and interpretation. This protocol will help physicians make rapid clinical decisions.