A review of the CLIP system for the quantitative analysis of two-dimensional electrophoresis gels.

This paper reviews the CLIP image processing system for the complete analysis of two-dimensional electrophoresis images. The analysis problem for two-dimensional gel images can be broken down into three issues: segmentation of individual gel images, alignment and comparison of pairs of gel images, and information storage and retrieval. This paper describes these problems and reviews how the CLIP system handles each of them. Segmentation is the location and isolation of each protein spot on an individual gel image and also the extraction of individual spot data such as position, area and volume. There are three basic stages: background field correction, noise filtering, spot detection and information extraction. Alignment and comparison of gel images involves matching protein spots between two gels. This can be quite difficult because there is not a simple relationship which can transform one gel image onto another. The database issues concern storing all the information which has been obtained from the above operations such that retrieval of this information can be readily performed. The advantage of the CLIP system over others is speed of processing. CLIP series computers use one processor for every pixel of the camera image such that image processing algorithms run in parallel. The main disadvantage is in the cost of these machines. With the declining trend in the cost of parallel processors, these machines will become more and more viable alternatives. This papers reviews the algorithms for the analysis of two-dimensional gels. It is shown that CLIP is flexible enough to perform more than one type of algorithm for a particular operation.

Neural attrition following limb loss and regeneration in juvenile lobsters.

Lobsters have considerable regenerative capacity, being able to regrow an entire, albeit smaller, limb in one intermolt. Whether there is a corresponding downscaling in the hemiganglion and its nerves to the regenerate side compared with its contralateral intact side was examined in juvenile lobsters which had undergone single or multiple (2, 4, and 6) cycles of limb loss and regeneration on the one side. The limbs studied were the enlarged thoracic chelipeds or claws which appeared as paired symmetrical cutter-type claws. The size of the regenerate limb, as indicated by its propus length, was approximately 30% smaller than its intact counterpart. Correspondingly, the total number of axons in the nerves to the regenerate side was smaller than on the intact, contralateral side. Such attrition was also by about 30% in lobsters experiencing a single cycle of limb loss and regeneration, but was considerably greater with multiple cycles. Tissue degeneration was occasionally seen in the nerves to the regenerate side but not in the ganglion. The paired hemiganglia were equivalent in all respects except in the size of the neuropil, which was smaller on the regenerate side compared with the contralateral intact side. Neuropil attrition was most marked with multiple cycles of limb loss and regeneration. Such attrition in nerve and neuropil are most likely due to the reduced number of sensory elements in the newly regenerated, but smaller, limb.

Parallel algorithms for querying data on two-dimensional electrophoresis gels.

This paper describes some parallel processing algorithms for the analysis of two-dimensional electrophoresis images. One of the largest processor arrays in the world, CLIP4, at University College London, was used in the research. The paper concentrates on algorithms using CLIP4 for querying the data produced on the gel images. It is shown that many typical queries that researchers request can be answered without removing the data from the processor array, eliminating slow transfer times due to the input/output bottleneck problem. The production of these data by CLIP4 has already been described in two previous papers in this journal. Improvements to the system for the future are also presented.

Development of bilateral asymmetry in sensory innervation to lobster claws.

Sensory innervation to the paired claws of the lobster. Homarus americanus, was examined during their differentiation from a bilaterally symmetric state to an asymmetric state of a slender cutter and a stout crusher claw. This was done by estimating the total number and size distribution of axons in the second nerve root which provides most (approximately 90%) of the innervation to the claws and has few, bilaterally distributed motor axons. The paired claws which are undifferentiated and resemble each other in the 1st larval stage correspondingly have nerve roots that are bilaterally symmetric. In early juvenile (4th and 5th) stages when claw type is determined, as well as in subsequent (6th, 7th, 8th, 16th) juvenile stages when the claws gradually differentiate into cutter and crusher types, the paired homologous roots are also similar. It is only in adults that asymmetry in sensory innervation is seen with more axons in the crusher root than in its cutter counterpart. The difference in number of axons between the dimorphic claws is related to differences in surface area between the claws. Thus, bilateral asymmetry in sensory innervation is acquired by the continual but differential addition of axons to the paired claws.

Parallel algorithms for the analysis of two-dimensional electrophoresis gels.

This paper describes some parallel processing algorithms for the analysis of two-dimensional electrophoresis images. The machine used for the processing was the CLIP4 Cellular Array Computer at University College, London, one of the largest processor arrays in the world. Included in this paper are an algorithm for centroid detection, Gaussian fitting algorithms, and an algorithm for the extraction of data out of the cellular array machine. It is shown that these parallel algorithms can run at a speed almost completely independent of the number of spots in the gel images.

Computer-assisted analysis of two-dimensional electrophoresis images using an array processor.

The CLIP4 machine has been used to analyze two-dimensional electrophoresis gel images. The architecture of the CLIP4 machine allows high-speed processing of gel images unavailable on conventional machines. The paper gives a brief review of the CLIP system followed by a detailed description of the segmentation and comparison algorithms. The segmentation algorithm makes full use of methods already designed for other gel analysis systems, but optimized for use on the highly parallel CLIP4 machine. The comparison algorithm is a totally new method using, to the full, the parallel efficiency of the CLIP4 computer. The algorithm attempts to match each spot on one gel with a corresponding spot on a second gel, operating simultaneously on all pairs of spots.

The modified bovine heterograft in vascular access for chronic hemodialysis.

The results of 100 modified bovine heterografts constructed in 93 patients for subcutaneous arteriovenous fistulas for chronic hemodialysis have been reviewed. Fifty-seven patients had the bovine heterograft inserted as the primary method of vascular access. Twenty-eight patients had complications consisting of graft thrombosis and stenosis, graft infection, and hemorrhage that required additional surgical procedures. Three patients with diabetes mellitus developed ischemia of the hand. Fourteen patients have died but none of the deaths could be attributable to the use of the bovine heterograft. In our experience the modified bovine heterograft has enjoyed a higher patient acceptance as compared to other methods of vascular access for hemodialysis. The chief advantage of the bovine graft has been the ability to use the graft in any patient as a means of immediate dialysis.