Multiple Discs Research Articles

Clinical Analysis of Chemonucleolysis for Treatment of Lumbar Disc Herniation

During last 48 months, in our department 51 patients with single or multiple herniated lumbar discs have received chemonucleolysis. Forty-one of 51 cases have single level herniation and remaining cases have multiple level. Age distribution were from 19 to 59 years old. Over 4 months(longest case: 18 months) follow up revealed as follows: 40 cases(78%) revealed excellent results: 4 cases(7.8%) received discectomy 3-6 months after chemonucleolysis because of recurred symtoms : no anaphylaxis and no major complications were noted.

Special purpose computers for information retrieval

This article reviews patent publications in the field of database processors for information retrieval. Emphasis is laid on associative processors, i.e. processors which reference data by content rather than by memory position or location. High speed is obtained by parallel manipulation of data from many channels of multiple head discs, magnetic bubble or other static memory devices. Very large databases use a combination of such a system and a directory system, i.e. a system comprising in addition to the main file other files containing a dictionary and pointers to the main file. Because of the importance of the associative memories, a survey thereof is also given.

Roles of ectodermal and endodermal epithelial cells in hydra morphogenesis: Analysis of chimeras

AbstractChimeric hydra were constructed from ectoderm of one strain and endoderm of a morphologically different strain. Body size and budding rate were assayed in three pairs of ectoderm/endoderm chimeras, which were chosen on the basis of their differences in size and budding rates. Reciprocal chimeras of one parental pair were the same size as their endodermal parent, while chimeras of another pair were closer to the ectodermal parents in size. Chimeras of the third pair were similar to one another in size, and intermediate in size between the parental strains. The budding rates of the three reciprocal pairs were similar to their ectodermal parents. This suggests that ectoderm exerts more influence than endoderm on budding rate, while both ectoderm and endoderm are capable of influencing the size of a hydra. The morphology of these three pairs of reciprocal chimeras and of a fourth pair of chimeras constructed from normal H. attenuata and a mutant strain which produces multiple basal discs were compared to the parental morphologies. Both ectoderm and endoderm contribute to the morphology of the chimeric strains.

Lumbar disc excision in children and adolescents.

Fifty patients, all of whom were sixteen years old or younger, underwent discectomy for a herniated lumbar disc at the Mayo Clinic between 1950 and 1976. Ninety-four per cent of the patients had had excellent or good initial relief of symptoms after the initial operation. Subsequently, however, twenty-eight of the thirty-seven patients who initially had undergone disc excision only required additional treatment for low-back pain or sciatica. Twelve of them required a second operation, consisting of nine discectomies (six with a concomitant spine fusion), two spine fusions alone, and one re-fusion. Of the thirty-seven patients who initially had had disc excision alone, three had a recurrent disc protrusion and five had a disc protrusion at another level. Of sixteen patients who had had multiple subtotal hemilaminectomies at the initial operation, either for involvement of multiple discs or for exploration, seven required reoperation. In the twelve patients who had had both a disc excision and a lumbar spine fusion as the initial operation, there were no recurrent disc protrusions and only one patient had a protrusion at another level. Follow-up on all patients ranged from five to thirty years (average, nineteen years). Ninety per cent of the patients stated that the condition of the back had little or no effect on their current way of life, despite the presence of continuing back complaints in some. However, we rated the results of the initial discectomy at follow-up as excellent or good in 73.5 per cent and poor in 26.5 per cent of the patients.

Annular tears in the dorsolumbar spine.

As part of a systemic study of the spine between D11 and S1 the distribution and severity of anterior and posterior annular tears has been assessed by charting the tears in sagittal slabs of 117 fresh specimens. No significant sex difference was seen. The number of cases with tears in multiple discs increases with age, but exceptions to this trend occurred in both young and elderly spines. Age adjusted correlation coefficients indicate that anterior and posterior tears at L4 and L5 do not predict tears at other levels. At L3 and above, significant positive correlations occur between multiple disc levels, particularly posteriorly. In patients 50o year old or more the mean anterior tear score rises sharply from L5 to peak at L2 and L1, but, in contrast, the mean posterior tear score falls from L4 to L1 in this age group. The increase in severity of anterior tears corresponds with increased mobility in the L4-L1 disc from 50-70 years. The data are compatible with 2 factors causing tears. One affects L4 and L5 in young adults and is possibly mechanical in nature; the second operates at a later age, promotes widespread disc involvement, and is primarily degenerative in nature. The increased prevalence and severity of anterior tears (and the associated increase in mobility) in the upper lumbar region in the middle aged and elderly may be a pathogenic factor in back pain for this age group.

An economical tonal display for interactive graphics and image analysis data

The use of tonal displays in image analysis and interactive graphics has always dictated the use of expensive refresh memories for the display output device. This has involved the use of high speed digital drums, multiple head discs, and analog storage tubes. Recently, the introduction of very long shift registers has allowed the designer to consider their use for refresh memories. A prototype display using 1024 bit MOS static shift registers has been developed. It has been shown that a reasonable cost versus performance tradeoff can be obtained. The first efforts has resulted in a 128 × 128 × 4 bit (64k) memory; it is now in the process of being expanded to 256 × 256 × 8 bits (512k). This memory is cost competitive with digital disc memories and both cost and performance competitive with storage tube scan converters.

Beam Plug for Radiation Shielding Penetrations

A beam line plug has been designed to fill the cylindrical hole formed by beam lines which pass through radiation shielding walls. The plug consists of multiple steel discs held together along their cylindrical axis by a steel cable forming a flexible snake-like structure. Other disc materials including laminates may be used to solve a variety of radiation shielding problems. When the beam line is to be used, the plug is pneumatically withdrawn into a vertical extension of vacuum line that is connected through a 90° bend to the beam line. Upon release, the plug is reinserted by pneumatic action. The beam plugs being used at the Brookhaven Three-stage MP Tandem Van de Graaff Facility are 7.6 cm diameter and provide 80 cm equivalent thickness of steel to fill penetrations through a 120 cm thick concrete wall. Fast-neutron measurements at the shielding wall surface show that the beam plug is indistinguishable from concrete shielding. A description of the beam plug mechanism, failsafe features, test results, and performance data is presented.

Presence of widened and multiple intercalated discs in the hypertrophied canine heart.

Fresh tissues were taken for light microscopy from the trabeculae carneae at the right ventricular base, apex, left ventricular base, and apex of four normal canine hearts and nine whose pulmonary artery had been banded for 7 to 48 weeks. After banding, the width of the intercalated disc at the right base, 1.34 ± 0.10 µ (mean ± SE), was greater than at the right apex, 1.02 ± 0.09 µ ( P <0.002); both were greater than the normals ( P <0.005 and P <0.001). The intercalated discs were wider than corresponding normals in only three hearts at the left base and six at the left apex. The mean widths of the discs correlated positively with both ventricular wall thickness and weight in the right ventricle but not in the left. Structures characterized by two, three, or four transverse segments of discs lying along the same myofibrils, each two of which are separated by 1 to 10 sarcomeres, have been named multiple intercalated discs. In six of the nine hearts whose pulmonary artery was banded, there were more multiple discs per mm 2 at the right base and right apex than in the corresponding normals ( P <0.02). In five of these, the number of multiple discs per mm 2 was greater at the right base than in the corresponding apex ( P <0.001). There was no significant increase in the number of multiple discs per mm 2 in either the left base or left apex of the experimental animals compared to controls. After banding the pulmonary artery, tension increases in the right ventricle and this stimulates a broadening of the folds of the discs and then triggers a mechanism for the formation of new sarcomeres, perhaps involving multiple intercalated discs.

A New Approach to Color Slow-Motion Video Recording

Since the introduction of slow-motion/stop-action video recorders for use in sports events, several different systems have been conceived to replay a picture instantly at normal speed, different rates of slow motion/stop-action, and reverse. All these systems used multiple discs or combinations of recorders. The recorder/reproducer described here uses just one disc which is addressed by two record/playback heads. One head records and plays back on the top of the disc, and the second records and plays back on the bottom. Starting at the disc's inside edge, field one is recorded on top of the disc; and field two is recorded directly below it on the bottom. The recording process continues across the disc, recording every other track to provide space for interleaving data on the return travel. To allow the operator to return quickly to points of interest for replay, a unique system of 30 tally lamps precisely indicates where the desired data is located on the disc.