Author
Rahul Rathi
Bio: Rahul Rathi is an academic researcher from Utrecht University. The author has contributed to research in topics: Sperm motility & Acrosome. The author has an hindex of 1, co-authored 1 publications receiving 283 citations.
Papers
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TL;DR: It was found that merocyanine 540 detects capacitation-related changes much earlier than CTC does, and that flow cytometry for evaluation of capacitation and AR was a quicker and more accurate technique than fluorescence microscopy.
Abstract: The primary aim of this study was to establish a flow cytometric technique for determining the capacitation status of stallion spermatozoa. To this end, a flow cytometric technique that demonstrates changes in plasma membrane fluidity; namely, merocyanine 540 staining, was compared with the more conventional Ca2+-dependent fluorescence microscopic technique, chlortetracycline (CTC) staining, for assessing capacitation status. In addition, the effect of bicarbonate/CO2 on the progress of capacitation and the acrosome reaction (AR) and on temporal changes in sperm motility, with particular regard to hyperactivation, was analyzed. For the study, fresh semen was washed and then incubated for 5 h in bicarbonate-containing or bicarbonate-free medium, with or without Ca2+ ionophore to induce the AR, and at intervals during incubation aliquots were taken and analyzed for capacitation and acrosome status. The AR was assessed using both the CTC and fluorescein isothiocyanate-peanut agglutinin (FITC-PNA) st...
298 citations
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TL;DR: The integrity of sperm DNA can be measured at three different levels by assessing the degree of DNA-protamine condensation, the incidence of breaks and nicks in the DNA and the frequency of fragmentation of the nuclei into sub-haploid apoptotic bodies.
316 citations
TL;DR: Flow cytometry is a tool that may be used in the future to monitor many new potential markers of sperm function and in conjunction with the flow cytometer, permit the evaluation of a large number of spermatozoa.
274 citations
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
TL;DR: Flow-cytometric analysis of sperm with appropriate probes offers considerable promise for the prediction of stallion fertility because it allows the objective, rapid and simultaneous analysis of a number of properties in a large number of sperm.
Abstract: Pregnancy rates in managed horse populations depend on the innate fertility of the mares and stallions involved and on the quality of breeding management. Of course, because a single stallion usually mates many mares, stallion fertility is a critical factor in the overall success of a breeding program. Unfortunately, accurate evaluation of stallion fertility per se requires a large number of normal mares to be mated and is necessarily retrospective. Rather, the ideal is to predict fertility in advance of the stallion's breeding career, and this is currently attempted by way of a thorough physical examination and a routine analysis of semen quality. However, while such a 'breeding soundness examination' identifies stallions that clearly lack the capacity for adequate fertility, it is of limited use for predicting the level of fertility and fails to identify some seriously sub-fertile animals. Similarly, while various sperm function tests (e.g., sperm head morphometry, the hypoosmotic swelling test, glass wool-sephadex filtration, progesterone receptor exposure) have been shown to correlate fairly well with fertility in the field, most examine only a single or a narrow range of the attributes that a sperm must possess if it is to fertilize an oocyte in vivo, and are thus more useful for identifying specific causes of sub-fertility than for predicting the level of fertility. On the other hand, combining the results of the various sperm function tests does improve the reliability of fertility estimation and current research is therefore concentrated on identifying a range of tests that covers as many important sperm attributes as possible but that can be performed rapidly and cheaply. In this respect, flow-cytometry has proven to be an ideal tool because it allows the objective, rapid and simultaneous analysis of a number of properties in a large number of sperm. Moreover, stains are available for an increasing range of sperm characteristics including viability, capacitation and acrosome status, mitochondrial activity and chromatin integrity. Flow-cytometric analysis of sperm with appropriate probes thus offers considerable promise for the prediction of stallion fertility.
214 citations
TL;DR: It is discovered that bicarbonate induces a rapid collapse of phospholipid transverse asymmetry, exposing phosphatidylethanolamine andosphatidylserine at the outer surface of the lipid bilayer, in conflict with earlier surmises that cholesterol loss precedes activation of the cyclic AMP-protein kinase A axis.
198 citations