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Biomedical subjects

C T Brighton

Publications and source records attributed to C T Brighton.

At least 109 records · Page 6Linked to original sources
PubMed1984

Treatment of avascular necrosis of the femoral head by a combination of bone grafting, decompression, and electrical stimulation.

The goal in the treatment of avascular necrosis is to preserve, not replace, the femoral head. Although many methods have been proposed, none has proved completely satisfactory. Electrical stimulation as a supplement to bone grafting and decompression is an attractive approach to this problem because it combines the desirable features of other procedures, each of which has shown a certain degree of effectiveness in stimulating bone growth and repair. Preliminary results indicate that patients treated with decompression and grafting alone and those in whom electrical stimulation was added to these had better results than patients treated by "conservative" means. The effectiveness of the electrical stimulation itself, however, has not yet been established and remains an important area for investigation. Further improvements in delivery systems and techniques are required to develop better methods for the treatment of avascular necrosis.

Bone Transplantation↗
PubMed1984

The growth plate.

The growth plate is an organ composed of cartilage, bone, and fibrous parts whose activities are synchronized to provide for longitudinal growth in the typical long bone. The morphology, function, and metabolism of the growth plate and its component parts are discussed in detail in this article.

Animals↗
PubMed1984

The biology of fracture repair.

Fracture healing or bone regeneration has been described histologically, histochemically, biochemically, physiologically, biophysically, and biomechanically. However, these various descriptive analyses do not answer the following all-important questions: What is the inductor(s) that incites cells to start forming bone at the fracture site? What are the responding cells that serve as progenitor cells for the osteoblasts and chondroblasts that appear in the interfragmentary gap? Do factors exist that are required to maintain the regenerating process to its conclusion? Until answers to these questions are found in the laboratory, we will not know "how" bone heals or regenerates itself.

Animals↗
PubMed1984

Treatment of nonunion of the scaphoid by direct current.

Seventy-one per cent (12 of 17) of scaphoid nonunions previously treated by other methods united when the semi-invasive technique of electrical stimulation was used. Patient acceptance of this electrode technique is high, and morbidity is lower than in patients treated by iliac bone grafting. The treatment of nonunion of the scaphoid by the semi-invasive electrical stimulation technique is a reasonable alternative to bone grafting and provides a salvage procedure when bone grafting or other therapeutic modalities have failed.

Carpal Bones↗
PubMed1984

Early results in the treatment of avascular necrosis of the femoral head with electrical stimulation.

Our goal in the treatment of avascular necrosis is to retard or reverse the progressive changes that normally take place and thus preserve rather than replace the femoral head. "Conservative" or nonoperative management has generally proved unsuccessful, and results with established surgical procedures have been inconsistent and frequently disappointing. A new approach has been described that uses direct-current stimulation in conjunction with bone grafting and decompression. Results were determined clinically and radiographically using a new method of staging and evaluation. The majority of patients who underwent surgery showed significant clinical improvement, especially in regard to pain relief. Some degree of radiologic progression, however, was detected in most cases, even in many with clinical improvement. Electrical stimulation, as used in this study, did not appear to alter the results obtained with decompression and grafting alone. It must be emphasized that this is a preliminary report. More data and longer follow-up will be required before definitive conclusions can be drawn, and we must continue our efforts to improve the management of avascular necrosis.

Adult↗
PubMed1983

In vivo growth plate stimulation in various capacitively coupled electrical fields.

The right proximal tibial growth plates of adolescent New Zealand white rabbits were stimulated with various capacitively coupled electrical fields. Capacitor plates attached to plastic jigs placed over the proximal tibiae were connected to function generators which supplied sine wave signals of 60 kHz frequency and various voltages (2.5, 5, 10, and 20 V peak-to-peak). At 0 h and at 48 h, each animal was labeled with intravenously injected oxytetracycline. For the next 48 h, each right proximal tibial growth plate was stimulated with one of the above electrical signals. At the end of the 48 h of stimulation, the animals were sacrificed, and the tibiae were excised; histological sections of the proximal growth plate in each tibia were made, and the distance the labels moved away from the bone-cartilage junction down into the metaphysis was measured under fluorescent microscopy. Results indicate that the rabbit growth plate can be consistently stimulated to statistically significant accelerated growth in a capacitively coupled electrical field. A dose-response effect was noted, with 5 V peak-to-peak exhibiting maximum growth acceleration. Thus, the application of the proper capacitively coupled electrical field significantly stimulated the rabbit growth plate at voltage and current levels that are safe for human use.

Animals↗
PubMed1983

Electrical osteogenesis by low direct current.

A constant direct current cathode was employed in the medullary canal of the rabbit tibia to investigate electrical osteogenesis at low current levels. Currents of 0.015 or 0.075 microA were delivered to the bone and the biological response was compared with contralateral controls receiving 20 microA. This investigation was performed to determine if electrical osteogenesis occurs at current levels below the previously studied range of 1-100 microA with stainless steel electrodes. New bone formed by 0.015 microA cathodes was statistically comparable with that found around inactive cathodes from an earlier pertinent study. The osteogenic response to 0.075 microA cathodes was significantly elevated above that to inactive ones, thus substantiating electrical osteogenesis for currents below 1 microA. However, it is evident that this does not demonstrate a further stimulatory range but that currents near 0.075 microA probably approach the lower significant limit for electrically induced bone growth with stainless steel electrodes.

Animals↗
PubMed1983

Biosynthesis of a low molecular weight collagen by rabbit growth plate cartilage organ cultures.

Analysis of [14C]-proline labeled proteins synthesized by organ cultures of rabbit growth plate cartilage slices revealed that this tissue synthesized a low molecular weight collagen in addition to Type II, 1 alpha, 2 alpha, and 3 alpha collagens. This collagen appears to be a distinct molecular species on the basis of electrophoretic mobility, hydroxyproline content and cyanogen bromide peptide mapping. In subsequent studies, a non-disulfide-bonded, higher molecular weight form of the same molecule was identified.

Animals↗
PubMed1983

Clinical and roentgenographic evaluation of nonunion of the forearm in relation to treatment with D.C. electrical stimulation.

A total of 50 nonunions of the forearm bones in 42 patients were reviewed. The mean age was 35.6 years, with the majority secondary to motor vehicle accidents. Five of the nine identified infections were due to primary closure of the initial open fracture. The middle third of the forearm was the most common site of the nonunion. The majority (96%) had significant displacement on the original roentgenograms. Open fractures were more apt to develop nonunions. A gap produced a significant therapeutic challenge and we conclude such are best managed with a bone graft. If a compression plate is applied in the presence of comminution, a bone graft is indicated. The overall success rate with 3 months of D.C. electrical stimulation in the absence of a gap or infection was 80.0%. This compares favorably with time-honored bone graft surgery for nonunion.

Adult↗
PubMed1983

Absence of the glycerol phosphate shuttle in the various zones of the growth plate.

UNLABELLED: The various zones of the growth plate of the rib of six-week-old male New Zealand White rabbits were obtained by means of a specially devised guillotine slicing apparatus. Cartilage slices from each zone were assayed enzymatically for activity of glycerol phosphate dehydrogenase by an adaptation of a fluorimetric technique based on the conversion of non-fluorescent resazurin to the highly fluorescent resorufin in the presence of nicotinamide adenine dinucleotide and the enzyme. No glycerol phosphate dehydrogenase activity was detectable in any zone of the growth plate, whereas control liver slices exhibited abundant enzyme activity. Thus the glycerol phosphate shuttle, one pathway whereby reducing equivalents are carried or shuttled from cytoplasmic nicotinamide adenine dinucleotide to the intramitochondrial respiratory chain, is entirely lacking in growth-plate chondrocytes. The lack of this enzyme, and the absence of the glycerol phosphate shuttle, may explain the high rate of lactate accumulation in the presence of ample oxygen concentration (aerobic accumulation) even though the Krebs cycle (tricarboxylic acid cycle) and electron transport are proceeding at normal rates. CLINICAL RELEVANCE: The growth plate is a complex structure whose metabolism is still not well understood. This study demonstrates that, in at least one metabolic pathway, the growth-plate chondrocyte does not resemble other normal cells. Only as we are able to formulate a more complete picture of the metabolism of the normal growth plate will be able to understand, and perhaps correct or prevent, those disease states in which growth-plate metabolism has bone away.

Animals↗
PubMed1982

Experimental hydroxyapatite synovial and articular cartilage calcification: light and electron microscopic studies.

Intraarticular calciphylaxis with cartilage and synovial calcification was produced in rabbits by oral administration of a single dose of dehydrotachysterol followed by an intraarticular injection of ferrous chloride. Synovial membrane apatite deposits were seen in the interstitium, on collagen fibers, and within cell vacuoles. In contrast, long-term administration of dehydrotachysterol alone induced only articular cartilage calcification. Such calcification was limited to the mid and deep zone of cartilage. Most calcium deposits were apatite-like crystals. Acute crystal-associated inflammation was not demonstrated in these specimens with crystals sequestered in synovial or cartilage tissue. Further studies on these models will examine the relation of apatite to joint disease.

Animals↗
PubMed1982

Quantitative zonal analysis of cytoplasmic structures of growth-plate chondrocytes in vivo and in vitro.

The cytoplasmic components of chondrocytes from the various zones of the rat costochondral junction, grown in vitro, were quantitated from electron micrographs using a point-counting technique, and the results were compared statistically with the cytoplasmic components of chondrocytes in the corresponding zones of the junction in vivo. Detectable changes occurred in vitro as early as after six hours of culture. The major changes that occurred in vitro were: an increase in the amount of lipid bodies in chondrocytes in the hypertrophic zone and in the bottom portion of the proliferative zone, failure of the chondrocytes in the bottom portion of the hypertrophic zone to increase in size, retention of intactness of the cell membrane of chondrocytes at the base of the hypertrophic zone, a decrease in the number of mitochondria in chondrocytes in the hypertrophic zone and in the middle and bottom portions of the proliferative zone, and a decrease in the number of holes in the cytoplasm of chondrocytes in the bottom one-half of the hypertrophic zone. In vitro hypertrophic chondrocytes of the growth plate demonstrated cellular changes associated with aging, while in vito the hypertrophic chondrocytes demonstrated changes associated with degeneration. The final result in both cases was cell death.

Aging↗
PubMed1981

Treatment of nonunion of the tibia with constant direct current (1980 Fitts Lecture, A.A.S.T.).

The technique for treating nonunion of the tibia by means of electricity delivered to the site by percutaneously inserted electrodes is described. Of 131 tibial nonunions so treated with constant direct current for 12 weeks, 107 (81.7%) achieved solid bony union. Analysis of the 24 failures in the series indicated that eight of the patients did not receive adequate electricity. Of the 123 patients who did receive adequate electrical treatment (four cathodes each delivering 20 microamperes continuously for 12 weeks), 107 (87%) achieved bony union. The presence of previous osteomyelitis at the fracture site or the presence of previously inserted metallic fixation devices did not effect the end result heal rate. Comparison of the rate of union reported in this study to rates of union reported in the literature for bone graft surgery reveal no statistically significant differences in the results achieved by the two methods. Since the risk/benefit ratio is lower for direct current treatment of nonunion than that associated with conventional bone graft surgery. It is concluded that the electrical treatment of nonunion promises to become the preferred method of treatment for that condition.

Adolescent↗