Asad Naeem

Validation of a novel computer-assisted sperm analysis (CASA) system using multitarget-tracking algorithms

OBJECTIVE To determine the accuracy and precision of a novel computer-assisted sperm analysis (CASA) system by comparison with existing recommended manual methods. DESIGN Prospective study using comparative measurements of sperm concentration and motility on latex beads and immotile and motile sperm. SETTING Tertiary referral fertility center with strong academic links. PATIENT(S) Sperm donors and male partners of couples attending for fertility investigations. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Achievement of Accubead target value for high and low concentration suspensions. Repeatability as demonstrated by coefficients of variation and intraclass correlation coefficients. Correlation and limits of agreement between CASA and manual methods. RESULT(S) The CASA measurements of latex beads and sperm concentrations demonstrated a high level of accuracy and repeatability. Repeated Accubead measurements attained the required target value (mean difference from target of 2.61% and 3.71% for high- and low-concentration suspensions, respectively) and were highly reproducible. Limits of agreement analysis suggested that manual and CASA counts compared directly could be deemed to be interchangeable. Manual and CASA motility measurements were highly correlated for grades a, b, and d but could not be deemed to be interchangeable, and manual motility estimates were consistently higher for motile sperm. CONCLUSION(S) The novel CASA system was able to provide semen quality measurements for sperm concentration and motility measurements which were at least as reliable as current manual methods.

High-throughput feature counting and measurement of roots

SUMMARY The original RootTrace tool has proved successful in measuring primary root lengths across time series image data. Biologists have shown interest in using the tool to address further problems, namely counting lateral roots to use as parameters in screening studies, and measuring highly curved roots. To address this, the software has been extended to count emerged lateral roots, and the tracking model extended so that strongly curved and agravitropic roots can be now be recovered. Here, we describe the novel image analysis algorithms and user interface implemented within the RootTrace framework to handle such situations and evaluate the results. AVAILABILITY The software is open source and available from http://sourceforge.net/projects/roottrace.

Recovering the dynamics of root growth and development using novel image acquisition and analysis methods

Roots are highly responsive to environmental signals encountered in the rhizosphere, such as nutrients, mechanical resistance and gravity. As a result, root growth and development is very plastic. If this complex and vital process is to be understood, methods and tools are required to capture the dynamics of root responses. Tools are needed which are high-throughput, supporting large-scale experimental work, and provide accurate, high-resolution, quantitative data. We describe and demonstrate the efficacy of the high-throughput and high-resolution root imaging systems recently developed within the Centre for Plant Integrative Biology (CPIB). This toolset includes (i) robotic imaging hardware to generate time-lapse datasets from standard cameras under infrared illumination and (ii) automated image analysis methods and software to extract quantitative information about root growth and development both from these images and via high-resolution light microscopy. These methods are demonstrated using data gathered during an experimental study of the gravitropic response of Arabidopsis thaliana.

Managing Particle Spread via Hybrid Particle Filter/Kernel Mean Shift Tracking

Particle filtering provides a well-developed and widely adopted approach to visual tracking. For effective tracking in real-world environments the particle set must sample widely enough that it can represent alternative target states in areas of ambiguity. It must not, however, become diffuse, spreading across the image plane rather than clustering around the object(s) of interest. A key issue in the design of particle filter-based trackers is how to manage the spread of the particle set to balance these conflicting requirements. To be computationally efficient, balance must be achieved with as small a particle set as reasonably possible. A number of hybrid particle filter/mean-shift trackers have recently been proposed. We believe that their strength lies in their ability to alternately disperse and cluster particles together, providing both a degree of balance and a reduced particle set. We present a novel hybrid of the annealed particle filter and kernel mean-shift algorithms that emphasises this behaviour. The algorithm has been applied to a wide variety of artificial and real image sequences. The method has performance and efficiency advantages over both pure kernel mean-shift and particle filtering trackers and existing hybrid algorithms

Brief communication: assessment and Validation of nonspermicidal condoms as Specimen collection Sheaths for Semen analysis and assisted conception

The choice of nonspermicidal sheaths for specimen collection for diagnosis and/or fertility treatment is limited. Those that are available tend to be relatively expensive and as a result, offered selectively to patients. This study describes the evaluation of three over-the-counter nonspermicidal condoms as alternatives to specialized specimen collection sheaths. Sheaths were incubated with motile sperm for up to 2 h and the percent Grade A motility, percent progressive motility and progressive velocity assessed using an ‘in-house’ computer-assisted semen analysis system every 30 min. Two of the sheaths tested, Pasante Naturelle (PN) and the Durex Avanti Ultima were shown to be highly toxic to sperm, leading to immobilization of most specimens within 1 h. However the loss of sperm motility when sperm were incubated with the Pasante Unique (PU) condom was no greater than with either the control (rigid 60 ml specimen container) or the Male Factor Pak (MFP), a commercially available specialized semen collection sheath. In conclusion, the PU brand of condom could be used as a cheaper alternative to the specimen collection sheaths currently available. Furthermore, some brands of condom sold as nonspermicidal are in fact toxic to sperm and will immobilize most specimens within 1 h.

Standards in reporting cryopreserved donor sperm characteristics: should they be reported post-thaw or post-wash?

An increase in the reliance on imported donor samples has been the consequence of a continued shortage of UK donors. Disputes can arise between suppliers and purchasers if the sperm quality is not as expected, yet there appears to be no requirement for the standardization of methods for sperm processing or analysis. Following analysis of 102 donor intrauterine insemination cycles, this study demonstrates that the motile sperm concentration is significantly (P < 0.05) reduced after the necessary removal of cryoprotectant before insemination. Suppliers of donor spermatozoa should therefore provide information on standards used for sperm assessment and whether analysis is performed before or after washing in order that purchasers are better informed about the quality of the end product they are committed to buying.