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Jens Peter Stenvang

Bio: Jens Peter Stenvang is an academic researcher. The author has contributed to research in topics: Sperm & Hemocytometer. The author has an hindex of 2, co-authored 2 publications receiving 101 citations.

Papers
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Journal ArticleDOI
TL;DR: A new flow cytometric method has been developed to rapidly determine sperm concentration and viability in semen from bulls and boars, and it was found that this system was two and four times more accurate than the spectrophotometer and the electronic cell counter, respectively.
Abstract: A new flow cytometric method has been developed to rapidly determine sperm concentration and viability in semen from bulls and boars. Sperm viability was determined on the basis of staining with SYBR-14 and propidium iodide (PI), and this allowed detection of live (membrane-intact) sperm, dying (moribund) sperm, as well as dead cells. Fluorescent microspheres (beads) were used to determine sperm concentration. The use of SYBR-14 at 50 nM and PI at 12 μM in combination with the FACSCount diluent in the counting tubes resulted in a uniform staining after 2.5–5 minutes at room temperature. Reagent staining was reproducible enough to allow subsequent semiautomated analysis of data using Attractors software. In experiment 1, this method was used to analyze semen from boars, rams, rats, rabbits, humans, and turkeys. In experiment 2, Attractors analysis was performed by the FACSCount AF flow cytometer, and sperm concentration determination with this system was compared with results obtained by a spectrophotometer and an electronic cell counter, which is routinely used by bull artificial insemination centers. When compared to microscopic counting in a hemocytometer, the FACSCount AF flow cytometer was two and four times more accurate than the spectrophotometer and the electronic cell counter, respectively. In addition, the FACSCount AF flow cytometer determined both sperm concentration (coefficient of variation 3.3%) and sperm viability (coefficient of variation 0.7%) with high precision.

74 citations

Patent
06 Mar 2000
TL;DR: In this article, a method for simultaneous determination of the total concentration of sperm cells and the proportion of live sperm cells in a semen sample is provided, which can distinguish between live, dead and/or dying sperm cells by detection of the fluorescent response from the sperm cells.
Abstract: A method for the simultaneous determination of the total concentration of sperm cells and the proportion of live sperm cells in a semen sample is provided. By selective staining of live, dead and/or dying sperm cells, for example using one or more fluorochromes, the detection means can distinguish between live, dead and/or dying sperm cells, for example by detection of the fluorescent response from the sperm cells. The selective staining may be performed at room temperature and in concentrations below standard concentrations. The determination may be performed by selective counting of cells of each fluorescent quality for example by using a flow cytometer having internal concentration standard means. Furthermore, the likelihood of fertilizing a female animal with an insemination dose, taken from a semen sample having a known total concentration of sperm cells and a known proportion of live sperm cells, is predicted on the basis of the thus determined total concentration of sperm cells and the proportion of live sperm cells.

34 citations


Cited by
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Patent
29 Mar 2004
TL;DR: In this article, a multi-channel system for classifying particles in a mixture of particles according to one or more characteristics including a common source of electromagnetic radiation for producing a beam of radiation and a beam splitter for producing multiple beams of radiation for each interrogation location associated with each flow channel of the system.
Abstract: A multi-channel system for classifying particles in a mixture of particles according to one or more characteristics including a common source of electromagnetic radiation for producing a beam of electromagnetic radiation and a beam splitter for producing multiple beams of electromagnetic radiation for directing multiple beams of electromagnetic radiation to each interrogation location associated with each flow channel of the multi-channel system.

218 citations

Journal ArticleDOI
TL;DR: The present and future capabilities of flow cytometry for the diagnostics of potential fertility and for the development of current reproductive technologies such as sperm freezing, sperm selection and sperm sorting are critically evaluated.
Abstract: Flow cytometry is now a recognized methodology within animal spermatology, and has moved from being a research tool to become routine in the assessment of animal semen destined to breeding. The availability of 'bench-top' flow cytometers and of newer and versatile markers for cell structure and function had allowed the instrumentation to measure more sperm parameters, from viability to reactiveness when exposed to exogenous stimuli, and to increase our capabilities to sort spermatozoa for potential fertilizing capacity, or chromosomal sex. The present review summarizes the state of the art regarding flow cytometry applied to animal andrology, albeit keeping an open comparative intent. It critically evaluates the present and future capabilities of flow cytometry for the diagnostics of potential fertility and for the development of current reproductive technologies such as sperm freezing, sperm selection and sperm sorting. The flow cytometry methods will probably further revolutionize our understanding of the sperm physiology and their functionality, and will undoubtedly extend its application in isolating many uncharacterized features of spermatozoa. However, continuous follow-up of the methods is a necessity owing to technical developments and the complexity of mapping spermatozoa.

143 citations

Journal ArticleDOI
TL;DR: This unit presents methods based on dye exclusion, esterase activity, and mitochondrial membrane potential, as well as protocols for determining the pre‐fixation viability of fixed cells either before or after fixation with amine‐reactive dyes suitable for a range of excitation wavelengths.
Abstract: Cell viability may be judged by morphological changes or by changes in membrane permeability and/or physiological state inferred from the exclusion of certain dyes or the uptake and retention of others. This unit presents methods based on dye exclusion, esterase activity, and mitochondrial membrane potential, as well as protocols for determining the pre-fixation viability of fixed cells either before or after fixation with amine-reactive dyes suitable for a range of excitation wavelengths. Membrane-impermeable dead cell and live cell dyes as well as dye-exclusion procedures for microscopy are also included.

134 citations

Journal ArticleDOI
TL;DR: The SCSA cytogram patterns were consistent for different ejaculates within boars and storage of extended boar semen at 18 degrees C for 72 h significantly decreased the integrity of sperm DNA.

105 citations

Journal ArticleDOI
TL;DR: It is concluded that duplicate counts by at least two technicians is recommended to achieve high precision but, that particular caution should be exerted with regard to the precision and accuracy of the used counting device.

94 citations