Name: evaluation of blood lactate and plasma insulin during high-intensity exercise by antecubital vein catheterization
Uploaded: 2018-05-18T12:30:00
Description: Watch this Scientific Journal Video about Evaluation of Blood Lactate and Plasma Insulin During High-intensity Exercise by Antecubital Vein Catheterization at JoVE.com

The authors would like to acknowledge Dr. P. Karagiannis for reading the paper and Professor T. Hoyo for his technical support.

All methods described here have been approved by the local ethical committee (Doshisha University Ethical Committee: 15033), and were in strict accordance with the standards set by the Declaration of Helsinki. Informed consent was obtained from all participants. Participants were male recreational athletes (age, 20.1 &#177; 1.2 years; weight, 69.7 &#177; 6.2 kg; height, 176.1 &#177; 5.8 cm; body fat 13.6 &#177; 1.5% and VO2max, 52.6 &#177; 6.6 mL/min1/kg1).
1. Es...

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	<li>Wahl, P., Mathes, S., K&#246;hler, K., Achtzehn, S., Bloch, W., Mester, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+active+vs.+passive+recovery+during+Wingate-based+training+on+the+acute+hormonal,+metabolic+and+psychological+response.">Effects of active vs. passive recovery during Wingate-based training on the acute hormonal, metabolic and psychological response.</a> Growth Horm IGF Res. 23 (6), 201-208 (2013).</li><li>Wahl, P., Mathes, S., Achtzehn, S., Bloch, W., Mester, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Active+vs.+passive+recovery+during+high-intensity+training+influences+hormonal+response.">Active vs. passive recovery during high-intensity training influences hormonal response.</a> Int J Sports Med. 35 (7), 583-589 (2014).</li><li>Nalbandian, H. M., Radak, Z., Takeda, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+active+recovery+during+interval+training+on+plasma+catecholamines+and+insulin.">Effects of active recovery during interval training on plasma catecholamines and insulin.</a> J Sports Med Phys Fitness. , (2017).</li><li>Stolen, T., Chamari, K., Castagna, C., Wislff, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiology+of+Soccer.">Physiology of Soccer.</a> Sport Med. 35 (6), 501-536 (2005).</li><li>Bangsbo, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+physiology+of+soccer--with+special+reference+to+intense+intermittent+exercise.">The physiology of soccer--with special reference to intense intermittent exercise.</a> Acta Physiol Scand Suppl. 619, 1-155 (1994).</li><li>MacInnis, M. J., Gibala, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiological+adaptations+to+interval+training+and+the+role+of+exercise+intensity.">Physiological adaptations to interval training and the role of exercise intensity.</a> J Physiol. 595 (9), 2915-2930 (2017).</li><li>Emberts, T., Porcari, J., Dobers-Tein, S., Steffen, J., Foster, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exercise+intensity+and+energy+expenditure+of+a+tabata+workout.">Exercise intensity and energy expenditure of a tabata workout.</a> J Sports Sci Med. 12 (3), 612-613 (2013).</li><li>Smith, J. C., Hill, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contribution+of+energy+systems+during+a+Wingate+power+test.">Contribution of energy systems during a Wingate power test.</a> Br J Sports Med. 25 (4), 196-199 (1991).</li><li>Dotan, R., Bar-Or, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Load+optimization+for+the+Wingate+Anaerobic+Test.">Load optimization for the Wingate Anaerobic Test.</a> Eur J Appl Physiol Occup Physiol. 51 (3), 409-417 (1983).</li><li>Carrasco-Benso, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+adipose+tissue+expresses+intrinsic+circadian+rhythm+in+insulin+sensitivity.">Human adipose tissue expresses intrinsic circadian rhythm in insulin sensitivity.</a> FASEB J. 30 (9), 3117-3123 (2016).</li><li>Hatfield, D. L., Nicoll, J. X., Kraemer, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+Circadian+Rhythm+on+Power,+Force,+and+Hormonal+Response+in+Young+Men.">Effects of Circadian Rhythm on Power, Force, and Hormonal Response in Young Men.</a> J Strength Cond Res. 30 (3), 725-732 (2016).</li></ol>

In this study, the antecubital vein was catheterized, and blood samples were successfully collected during a high interval exercise. As an example of the use of this methodology, blood samples were analyzed for blood lactate and (after plasma separation) for plasma insulin. The main advantage of this method is that it allows the collection of blood samples in short periods of time. At the same time, it does have some limitations. For instance, the limited exercise modalities that allow its use; the number of assistant ne...

The measurement of metabolic and endocrinal markers during physical activity is of relevance to understanding the physiological implications of different exercise modalities. During some exercise modalities (e.g., high-intensity interval exercise (HIIE)), blood metabolites and hormonal levels fluctuate in relatively short time1,2,3.
Many sports (i.e., soccer, basketball, and rugby) consist of short periods of high-intensity exercise separated by low intense exercise and/or passive periods4,5. HIIE presents similarities with the aforementioned sports and is therefore widely used as a training method for athletes6. Moreover, because of its similarity with sports, HIIE has been used as a model to study exercise physiology7. Blood sampling is critical to measure physiological variables, and it is frequently used for research purposes and the evaluation of the physical condition. However, blood sampling during HIIE can be technically difficult because of the short time between sample collections. As a solution to this problem, here we present a method to obtain blood samples by antecubital venous catheterization in short periods of time while subjects perform HIIE.

<table border="0" cellpadding="0" cellspacing="0" width="626">
	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Cycle ergometer</td>
			<td style="width:71px;">Monark</td>
			<td colspan="2" style="width:339px;">MONARK Ergomedic 874 E</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Catheter</td>
			<td style="width:71px;">Terumo</td>
			<td style="width:172px;">SR-FF2032</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Vacutainer</td>
			<td style="width:71px;">Terumo</td>
			<td>PZ-D03</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Tube for catheter</td>
			<td style="width:71px;">Terumo</td>
			<td style="width:172px;">SP-PTW30L02</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Heparin</td>
			<td style="width:71px;">Terumo</td>
			<td>PF-10HF10UA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lactate pro2</td>
			<td style="width:71px;">Arkray</td>
			<td>&#65324;&#65332;-1730</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Insulin ELISA kit</td>
			<td>Abnova</td>
			<td>ELISA Kit KA0921</td>
			<td></td>
		</tr>
	</tbody>
</table>

evaluation of blood lactate and plasma insulin during high-intensity exercise by antecubital vein catheterization

The measurement of metabolic and endocrinal markers during physical activity is of relevance to understanding the physiological implications of different exercise modalities. During some exercise modalities (e.g., high-intensity interval exercise), blood metabolites and hormonal levels change in short periods of time. In the present study, we describe a method to catheterize the antecubital vein, which allows the collection of several blood samples during exercise. Insulin and venous lactate concentrations were measured during high-intensity exercise by the application of the described method. The exercise consisted of three 30 s bouts of high-intensity exercise separated by 4 min of recovery. After the last recovery period, a Wingate test was performed. Blood samples from the antecubital vein were obtained before and after each 30 s bout and before and after the Wingate test. As a result, it was possible to evaluate the plasma insulin and venous blood lactate variations during the exercise.

As representative results, we used this protocol to measure blood lactate and insulin variation in six subjects during a HIIE in a cycle ergometer. Peak power and Average Power for the Wingate test were 732 &#177; 120 and 549 &#177; 84 Watts, respectively. Average Power was used to calculate the power output (494 &#177; 75 Watts) during the 30 s bouts of the HIIE.
Figure 2 shows plasma insulin and b...

Watch this Scientific Journal Video about Evaluation of Blood Lactate and Plasma Insulin During High-intensity Exercise by Antecubital Vein Catheterization at JoVE.com

Evaluation of Blood Lactate and Plasma Insulin During High-intensity Exercise by Antecubital Vein Catheterization

Here we present a protocol to obtain several blood samples from the antecubital vein during high-intensity interval training. This protocol may be useful for the measurement of blood metabolites and endocrinal markers during exercise.

The measurement of metabolic and endocrinal markers during physical activity is of relevance to understanding the physiological implications of different ...

The overall goal of this experiment is to obtain multiple venous blood samples from a single subject during cycle ergometer exercise. This measure can help answer key questions in porous physiology and hormonal and metabolized variation during different exercise modalities. The main advantage of this technique is that multiple blood samples can be obtained, even during exercise.Demonstrating the procedures will be Rie Oosaki who collaborate with our laboratory. To evaluate blood, hormonal, and metabolite dynamics from the antecubital vein during high intensity interval exercise protocol, have the subject first perform a five-minute warmup on the ergometer at low-intensity. After a five minute rest, have the subject perform three 30 second high-intensity exercise intervals at 90 percent intensity at the power average determined from a previously performed Wingate test, separated by four minutes of rest per exercise interval.For blood sample collection, tie a tourniquet around the arm selected for the catheterization and identify the antecubital vein. Sterilize the skin with alcohol and insert the tip of a sterilized cannula into the antecubital vein and in an approximately 15 degree angle to the skin. If the cannulation is successful, a backflash of blood should be observed.After removing the needle, secure the cannula, and place a cotton tissue under the needle. Remove heparin with an empty collection tube and connect a new container for blood collection to the cannula. Aspirate approximately 2.5 ml of blood and close the butterfly, immediately placing the sample on ice.Then, inject heparin the full length of the tube to avoid blood sample coagulation, and have the subject begin the next series of exercise intervals. After the last sample has been collected, carefully remove the cannulation tube and disinfect the skin with more alcohol. Gently press a piece of sterile cotton onto the collection site to minimize bleeding and transfer 1.5 ml of blood from each sample into individual 1.5 ml microcentrifuge tubes on ice.Use the lactate detector, measure the blood lactate of each 1 ml blood sample, and centrifuge twice the 1.5 ml blood sample aliquots. Transfer the supernatants into new mirocentrifuge tubes, and centrifuge the samples again in transfer supernatants to new tubes. Then store the purified plasma samples at minus 80 degree Celsius until plasma insulin analysis by ELISA.In this representative experiment, plasma insulin levels decreased in all six patient peripheral blood samples during the first and third 30 second high intensity interval exercise periods, but increased during the second interval in recovery periods. Plasma lactate, however, decreased during the second and third 30 second high intensity interval exercise periods and increased during the first 30 second interval and recovery periods. While attempting this procedure, it is important to remember to maintain the blood samples at no colder than 40 degrees Celsius.Following this procedure, other methods like Brodgar's Analysis can be performed to answer additional questions about pH level variations during exercise. After watching this video, you should have a good understanding of how to collect consecutive blood samples from the antecubital vein during cycle ergometer exercise.

evaluation-blood-lactate-plasma-insulin-during-high-intensity

Research

JoVE Journal

Immunology and Infection

Depletion of Specific Cell Populations by Complement Depletion

The purification of immune cell populations is often required in order to study their unique functions. In particular, molecular approaches such as real-time PCR and microarray analysis require the isolation of cell populations with high purity. Commonly used purification strategies include fluorescent activated cell sorting (FACS), magnetic bead separation and complement depletion. Of the three strategies, complement depletion offers the advantages of being fast, inexpensive, gentle on the cells and a high cell yield. The complement system is composed of a large number of plasma proteins that when activated initiate a proteolytic cascade culminating in the formation of a membrane-attack complex that forms a pore on a cell surface resulting in cell death1. The classical pathway is activated by IgM and IgG antibodies and was first described as a mechanism for killing bacteria. With the generation of monoclonal antibodies (mAb), the complement cascade can be used to lyse any cell population in an antigen-specific manner. Depletion of cells by the complement cascade is achieved by the addition of complement fixing antigen-specific antibodies and rabbit complement to the starting cell population. The cells are incubated for one hour at 37&deg;C and the lysed cells are subsequently removed by two rounds of washing. MAb with a high efficiency for complement fixation typically deplete 95-100% of the targeted cell population. Depending on the purification strategy for the targeted cell population, complement depletion can be used for cell purification or for the enrichment of cell populations that then can be further purified by a subsequent method.

To effectively study the function of immune cell populations their purification is often required. Complement depletion is a fast and inexpensive technique for the isolation of immune cell populations with high purity.

The purification of immune cell populations is often required in order to study their unique functions.  In particular, molecular approaches such as ...

Isolation of Mouse Peritoneal Cavity Cells

The peritoneal cavity is a membrane-bound and fluid-filled abdominal cavity of mammals, which contains the liver, spleen, most of the gastro-intestinal tract and other viscera. It harbors a number of immune cells including macrophages, B cells and T cells. The presence of a high number of na&iuml;ve macrophages in the peritoneal cavity makes it a preferred site for the collection of na&iuml;ve tissue resident macrophages (1). The peritoneal cavity is also important to the study of B cells because of the presence of a unique peritoneal cavity-resident B cell subset known as B1 cells in addition to conventional B2 cells. B1 cells are subdivided into B1a and B1b cells, which can be distinguished by the surface expression of CD11b and CD5. B1 cells are an important source of natural IgM providing early protection from a variety of pathogens (2-4). These cells are autoreactive in nature (5), but how they are controlled to prevent autoimmunity is still not understood completely. On the contrary, CD5+ B1a cells possess some regulatory properties by virtue of their IL-10 producing capacity (6). Therefore, peritoneal cavity B1 cells are an interesting cell population to study because of their diverse function and many unaddressed questions associated with their development and regulation. The isolation of peritoneal cavity resident immune cells is tricky because of the lack of a defined structure inside the peritoneal cavity. Our protocol will describe a procedure for obtaining viable immune cells from the peritoneal cavity of mice, which then can be used for phenotypic analysis by flow cytometry and for different biochemical and immunological assays.

The peritoneal cavity in mammals contains different immune cell populations crucial for innate immune responses. An efficient isolation method is required for biochemical and functional analyses of these cells. Here we provide a comprehensive method for the isolation of peritoneal cavity cells in the mouse.

The peritoneal cavity is a membrane-bound and fluid-filled abdominal cavity of mammals, which contains the liver, spleen, most of the gastro-intestinal ...

Purification of Specific Cell Population by Fluorescence Activated Cell Sorting (FACS)

Experimental and clinical studies often require highly purified cell populations.  FACS is a technique of choice to purify cell populations of known phenotype.  Other bulk methods of purification include panning, complement depletion and magnetic bead separation.  However, FACS has several advantages over other available methods.  FACS is the preferred method when very high purity of the desired population is required, when the target cell population expresses a very low level of the identifying marker or when cell populations require separation based on differential marker density.  In addition, FACS is the only available purification technique to isolate cells based on internal staining or intracellular protein expression, such as a genetically modified fluorescent protein marker.  FACS allows the purification of individual cells based on size, granularity and fluorescence.  In order to purify cells of interest, they are first stained with fluorescently-tagged monoclonal antibodies (mAb), which recognize specific surface markers on the desired cell population (1).  Negative selection of unstained cells is also possible.  FACS purification requires a flow cytometer with sorting capacity and the appropriate software.  For FACS, cells in suspension are passed as a stream in droplets with each containing a single cell in front of a laser.  The fluorescence detection system detects cells of interest based on predetermined fluorescent parameters of the cells.  The instrument applies a charge to the droplet containing a cell of interest and an electrostatic deflection system facilitates collection of the charged droplets into appropriate collection tubes (2).  The success of staining and thereby sorting depends largely on the selection of the identifying markers and the choice of mAb.  Sorting parameters can be adjusted depending on the requirement of purity and yield.  Although FACS requires specialized equipment and personnel training, it is the method of choice for isolation of highly purified cell populations.

Purification of Specific Cell Population by Fluorescence Activated Cell Sorting FACS

For many scientific studies requiring a biological and chemical analysis of cell populations the cells must be in a high state of purity. Fluorescence activated cell sorting (FACS) is a superior method in which to obtain pure cell populations.

Experimental and clinical studies often require highly purified cell populations.  FACS is a technique of choice to purify cell populations of known ...

Finger-stick Blood Sampling Methodology for the Determination of Exercise-induced Lymphocyte Apoptosis

Exercise is a physiological stimulus capable of inducing apoptosis in immune cells. To date, various limitations have been identified with the measurement of this phenomenon, particularly relating to the amount of time required to isolate and treat a blood sample prior to the assessment of cell death. Because of this, it is difficult to determine whether reported increases in immune cell apoptosis can be contributed to the actual effect of exercise on the system, or are a reflection of the time and processing necessary to eventually obtain this measurement. In this article we demonstrate a rapid and minimally invasive procedure for the analysis of exercise-induced lymphocyte apoptosis. Unlike other techniques, whole blood is added to an antibody panel immediately upon obtaining a sample. Following the incubation period, red blood cells are lysed and samples are ready to be analyzed. The use of a finger-stick sampling procedure reduces the volume of blood required, and minimizes the discomfort to subjects.

Exercise is capable of inducing apoptosis in immune cells. There are various measurement limitations, particularly relating to the amount of time required to isolate and treat a blood sample prior to the assessment. Demonstrated is a rapid and minimally invasive procedure for the analysis of exercise-induced lymphocyte apoptosis.

Exercise is a physiological stimulus capable of inducing apoptosis in immune cells. To date, various limitations have been identified with the measurement ...

Antigens Protected Functional Red Blood Cells By The Membrane Grafting Of Compact Hyperbranched Polyglycerols

Red blood cell (RBC) transfusion is vital for the treatment of a number of acute and chronic medical problems such as thalassemia major and sickle cell anemia 1-3. Due to the presence of multitude of antigens on the RBC surface (~308 known antigens 4), patients in the chronic blood transfusion therapy develop alloantibodies due to the miss match of minor antigens on transfused RBCs 4, 5. Grafting of hydrophilic polymers such as polyethylene glycol (PEG) and hyperbranched polyglycerol (HPG) forms an exclusion layer on RBC membrane that prevents the interaction of antibodies with surface antigens without affecting the passage of small molecules such as oxygen ,glucose, and ions3. At present no method is available for the generation of universal red blood donor cells in part because of the daunting challenge presented by the presence of large number of antigens (protein and carbohydrate based) on the RBC surface and the development of such methods will significantly improve transfusion safety, and dramatically improve the availability and use of RBCs. In this report, the experiments that are used to develop antigen protected functional RBCs by the membrane grafting of HPG and their characterization are presented. HPGs are highly biocompatible compact polymers 6, 7, and are expected to be located within the cell glycocalyx that surrounds the lipid membrane 8, 9 and mask RBC surface antigens10, 11.

The cell membrane modification of red blood cells (RBCs) with hyperbranched polyglycerol (HPG) is presented. Modified RBCs were characterized by aqueous two phase partitioning, osmotic fragility and complement mediated lysis. The camouflage of surface proteins and antigens was evaluated using the flow cytometry and Micro Typing System (MTS) blood phenotyping cards.

Red blood cell (RBC) transfusion is vital for the treatment of a number of acute and chronic medical problems such as thalassemia major and sickle cell ...

Detecting Glycogen in Peripheral Blood Mononuclear Cells with Periodic Acid Schiff Staining

Periodic acid Schiff (PAS) staining is an immunohistochemical technique used on muscle biopsies and as a diagnostic tool for blood samples. Polysaccharides such as glycogen, glycoproteins, and glycolipids stain bright magenta making it easy to enumerate positive and negative cells within the tissue. In muscle cells PAS staining is used to determine the glycogen content in different types of muscle cells, while in blood cell samples PAS staining has been explored as a diagnostic tool for a variety of conditions. Blood contains a proportion of white blood cells that belong to the immune system. The notion that cells of the immune system possess glycogen and use it as an energy source has not been widely explored. Here, we describe an adapted version of the PAS staining protocol that can be applied on peripheral blood mononuclear immune cells from human venous blood. Small cells with PAS-positive granules and larger cells with diffuse PAS staining were observed. Treatment of samples with amylase abrogates these patterns confirming the specificity of the stain. An alternate technique based on enzymatic digestion confirmed the presence and amount of glycogen in the samples. This protocol is useful for hematologists or immunologists studying polysaccharide content in blood-derived lymphocytes.

Periodic acid Schiff staining is a technique that visualizes the polysaccharide content of tissues. This article demonstrates periodic acid Schiff staining protocol adapted for use on peripheral blood mononuclear cells purified from human venous blood. Such samples are enriched for lymphocytes and other white blood cells of the immune system.

Periodic acid Schiff (PAS) staining is an immunohistochemical technique used on muscle biopsies and as a diagnostic tool for blood samples. ...

A RAPID Method for Blood Processing to Increase the Yield of Plasma Peptide Levels in Human Blood

Research in the field of food intake regulation is gaining importance. This often includes the measurement of peptides regulating food intake. For the correct determination of a peptide&#39;s concentration, it should be stable during blood processing. However, this is not the case for several peptides which are quickly degraded by endogenous peptidases. Recently, we developed a blood processing method employing Reduced temperatures, Acidification, Protease inhibition, Isotopic exogenous controls and Dilution (RAPID) for the use in rats. Here, we have established this technique for the use in humans and investigated recovery, molecular form and circulating concentration of food intake regulatory hormones. The RAPID method significantly improved the recovery for 125I-labeled somatostatin-28 (+39%), glucagon-like peptide-1 (+35%), acyl ghrelin and glucagon (+32%), insulin and kisspeptin (+29%), nesfatin-1 (+28%), leptin (+21%) and peptide YY3-36 (+19%) compared to standard processing (EDTA blood on ice, p&#160;&#60;0.001). High performance liquid chromatography showed the elution of endogenous acyl ghrelin at the expected position after RAPID processing, while after standard processing 62% of acyl ghrelin were degraded resulting in an earlier peak likely representing desacyl ghrelin. After RAPID processing the acyl/desacyl ghrelin ratio in blood of normal weight subjects was 1:3 compared to 1:23 following standard processing (p&#160;= 0.03). Also endogenous kisspeptin levels were higher after RAPID compared to standard processing (+99%, p&#160;= 0.02). The RAPID blood processing method can be used in humans, yields higher peptide levels and allows for assessment of the correct molecular form.

The RAPID blood processing method can be used in humans and yields higher peptide levels as well as allows for assessment of the correct molecular form. Therefore, this method will be a valuable tool in peptide research.

Research in the field of food intake regulation is gaining importance. This often includes the measurement of peptides regulating food intake. For the ...

Molecular Diffusion in Plasma Membranes of Primary Lymphocytes Measured by Fluorescence Correlation Spectroscopy

Fluorescence correlation spectroscopy (FCS) is a powerful technique for studying the diffusion of molecules within biological membranes with high spatial and temporal resolution. FCS can quantify the molecular concentration and diffusion coefficient of fluorescently labeled molecules in the cell membrane. This technique has the ability to explore the molecular diffusion characteristics of molecules in the plasma membrane of immune cells in steady state (i.e., without processes affecting the result during the actual measurement time). FCS is suitable for studying the diffusion of proteins that are expressed at levels typical for most endogenous proteins. Here, a straightforward and robust method to determine the diffusion rate of cell membrane proteins on primary lymphocytes is demonstrated. An effective way to perform measurements on antibody-stained live cells and commonly occurring observations after acquisition are described. The recent advancements in the development of photo-stable fluorescent dyes can be utilized by conjugating the antibodies of interest to appropriate dyes that do not bleach extensively during the measurements. Additionally, this allows for the detection of slowly diffusing entities, which is a common feature of proteins expressed in cell membranes. The analysis procedure to extract molecular concentration and diffusion parameters from the generated autocorrelation curves is highlighted. In summary, a basic protocol for FCS measurements is provided; it can be followed by immunologists with an understanding of confocal microscopy but with no other previous experience of techniques for measuring dynamic parameters, such as molecular diffusion rates.

A method to measure protein diffusion in membranes of primary immune cells using fluorescence correlation spectroscopy (FCS) is described. In this paper, the use of antibodies for fluorescent labeling is illustrated.

Fluorescence correlation spectroscopy (FCS) is a powerful technique for studying the diffusion of molecules within biological membranes with high spatial ...

Dextran Enhances the Lentiviral Transduction Efficiency of Murine and Human Primary NK Cells

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining the role of the gene of interest in the development, differentiation, and function of NK cells. Recent advances related to chimeric antigen receptors (CARs) in cancer immunotherapy accentuate the need for an efficient method to deliver exogenous genes to effector lymphocytes. The efficiencies of lentiviral-mediated gene transductions into primary human or mouse NK cells remain significantly low, which is a major limiting factor. Recent advances using cationic polymers, such as polybrene, show an improved gene transduction efficiency in T cells. However, these products failed to improve the transduction efficiencies of NK cells. This work shows that dextran, a branched glucan polysaccharide, significantly improves the transduction efficiency of human and mouse primary NK cells. This highly reproducible transduction methodology provides a competent tool for transducing human primary NK cells, which can vastly improve clinical gene delivery applications and thus NK cell-based cancer immunotherapy.

The goal of this study was to formulate technologies that allow for successful gene transduction in primary natural killer (NK) cells. The dextran-mediated lentiviral transduction of human or mouse primary NK cells results in higher gene expression efficiencies. This method of gene transduction will vastly improve NK cell genetic manipulation.

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining ...

Measuring Deformability and Red Cell Heterogeneity in Blood by Ektacytometry

Decreased red cell deformability is characteristic of several disorders. In some cases, the extent of defective deformability can predict severity of disease or occurrence of serious complications. Ektacytometry uses laser diffraction viscometry to measure the deformability of red blood cells subject to either increasing shear stress or an osmotic gradient at a constant value of applied shear stress. However, direct deformability measurements are difficult to interpret when measuring heterogenous blood that is characterized by the presence of both rigid and deformable red cells. This is due to the inability of rigid cells to properly align in response to shear stress and results in a distorted diffraction pattern marked by an exaggerated decrease in apparent deformability. Measurement of the degree of distortion provides an indicator of the heterogeneity of the erythrocytes in blood. In sickle cell anemia, this is correlated with the percentage of rigid cells, which reflects the hemoglobin concentration and hemoglobin composition of the erythrocytes. In addition to measuring deformability, osmotic gradient ektacytometry provides information about the osmotic fragility and hydration status of erythrocytes. These parameters also reflect the hemoglobin composition of red blood cells from sickle cell patients. Ektacytometry measures deformability in populations of red cells and does not, therefore, provide information on the deformability or mechanical properties of individual erythrocytes. Regardless, the goal of the techniques described herein is to provide a convenient and reliable method for measuring the deformability and cellular heterogeneity of blood. These techniques may be useful for monitoring temporal changes, as well as disease progression and response to therapeutic intervention in several disorders. Sickle cell anemia is one well-characterized example. Other potential disorders where measurements of red cell deformability and/or heterogeneity are of interest include blood storage, diabetes, Plasmodium infection, iron deficiency, and the hemolytic anemias due to membrane defects.

Here we present techniques to measure red cell deformability and cellular heterogeneity by ektacytometry. These techniques are applicable to general investigations of red cell deformability and specific investigations of blood diseases characterized by the presence of both rigid and deformable red cells in circulation, such as sickle cell anemia.

Decreased red cell deformability is characteristic of several disorders. In some cases, the extent of defective deformability can predict severity of ...