Biomedical subjects
Publications and source records attributed to T K Taylor.
The discovery of antibiotics, total joint replacement and minimally invasive surgery have changed the face of orthopaedic surgery in the last 80 years. Most of these advances have been biomechanical, but the time has come for more fundamental research into tissue biology.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A case of a radiation-induced osteochondroma occurring in the posterior elements of the L3 vertebra in a 29-year-old woman is reported. At age 16 months, the patient was treated for an abdominal neuroblastoma. There were also radiation changes affecting the spine, ribs, and ilium. The lesion was excised "en bloc" and a spinal fusion performed. This is the third reported case of such a lesion occurring in the lumbar spine consequent to radiation therapy. The extremely long, latent period between radiation treatment and diagnosis of secondary tumor should be noted.
Proteoglycans (PGs) were isolated from 4 M GuHCl extracts of young adult ovine Intervertebral disc (IVD) tissues using sequential CsCl density gradient centrifugation, and a combination of gel-permeation and hydrophobic chromatography. A total of six PG sub-populations were identified in both the Annulus fibrosus (AF) and Nucleus pulposus (NP), i.e. two high buoyant density aggregatable PGs, two high buoyant density non-aggregatable PGs and two small, low-intermediate buoyant density, non-aggregatable, DS-rich PG species. These latter PGs were identified as biglycan and decorin on the basis of analyses of their core protein native size, and glycosaminoglycan composition. Additional low-intermediate buoyant density PG species were also evident in the non-aggregatable PG pool, particularly in extracts of NP tissues. These PGs did not bind to the octyl affinity matrix under the experimental conditions employed and thus were readily separated from the DS-PGs by hydrophobic chromatography, their constituent glycosaminoglycans (CS and KS) also differed and were of a smaller size to the CS and KS chains isolated from the large high buoyant density PGs, the small PGs which did not bind to octyl-sepharose may therefore represent distinct PG species in their own right. Differences were evident in the absolute size, and in the distribution of individual PG species in the respective IVD tissues but the NP always contained a larger proportion of high buoyant density non-aggregatable PGs of somewhat smaller size than those isolated from the AF. Decorin and biglycan, however, were generally more abundant in AF tissues.
The polymerase chain reaction (PCR) was used to develop a test for the detection of Mycoplasma mycoides subspecies mycoides SC in the tissues of animals infected with contagious bovine pleuropneumonia (CBPP). Two sets of primers were designed; one set (MC323/MC358) to amplify a approximately 1.5-kbp DNA fragment from all the members of the M. mycoides 'Cluster' and the other set (MM450/MM451) specifically amplified a 574-bp DNA fragment from M. mycoides subspecies. The PCR products could be differentiated further by digestion with the restriction enzyme AsnI. Enzyme digestion of amplification products from M. m. mycoides SC produced 2 fragments, whereas the other 2 M. mycoides subspecies, M. m. mycoides LC and M. m. capri, produced 3 fragments. This test was shown to be very sensitive, being able to detect between 10 and 100 organisms. Cattle were experimentally infected with the Gladysdale strain of M. m. mycoides SC, and samples of serum and mucus were taken periodically, as were postmortem samples of lung, lymph node, pleural fluid, synovial fluid, and tracheal swabs. Complement fixation test on serum samples, culture of postmortem tissues, and histopathologic examination confirmed disease. DNA was extracted from postmortem samples and amplified by PCR using primers MM450 and MM451. Digestion of products using AsnI allowed the specific identification of M. m. mycoides SC. This test could confirm CBPP in 48 hours and was thus capable of giving a more rapid result than the traditional methods of culture, isolation, and identification using biochemical and serological techniques.
A child with spondyloepiphyseal dysplasia congenita was shown to be heterozygous for a mutation of the COL2A1 gene that encodes the alpha 1 (II) chain of type II collagen. The alpha 1 (II) chains extracted from cartilage contained disulfide-bonded dimeric and trimeric alpha 1 (II) chains. Carboxymethylation confirmed that some of the type II collagen chains contained cysteine residues that are not normally present in alpha 1 (II) chains. Cyanogen bromide peptide mapping showed that the abnormal cysteine residue was located in the alpha 1 (II) CB10.5 peptide. Amplification products of the corresponding region of alpha 1 (II) cDNA prepared from cultured dermal fibroblasts were shown by chemical cleavage and single strand conformation polymorphism analyses to contain a sequence anomaly. DNA sequencing showed a transition of C2913T in exon 41 of one allele of the COL2A1 gene resulting in the substitution of arginine 789 by cysteine in the alpha 1 (II) chain. The mutation resulted in the loss of a MaeII cleavage site that was used to confirm that the proband was heterozygous for the mutation and that neither parent showed evidence of the mutation. The type II collagen extracted from cartilage and from chondrocytes cultured in alginate beads showed similar characteristics. Approximately a third of the type II collagen chains were mutant, and the secretion of molecules containing mutant chains was impaired. The thermal stability of the collagen extracted from cartilage was normal. This study confirmed the importance of dominant negative mutations of the COL2A1 gene in producing the spondyloepiphyseal dysplasia congenita phenotype.
Total medial meniscectomy was performed in 12 adult merino sheep. Immediately after surgery, 8 animals received high-molecular-weight hyaluronan (HA) (1 mL, 10 mg/mL) and 4 were given sterile saline (1 mL) intraarticularly. Injections were given for 5 more weeks. In week 3 an exercise program, consisting of walking 24 km/wk, was initiated. This program was continued until the animals were killed at week 26 postmeniscectomy. At necropsy the lateral menisci were removed and divided into three concentric zones--inner, middle, and outer. Powdered aliquots of tissues from each zone were analyzed for collagen and hexuronate contents using colormetric methods. The glycosaminoglycans (GAGs)--chondroitin-O-sulfate (C-O-S), chondroitin-4-sulfate (C-4-S), chondroitin-6-sulfate (C-6-S), and dermatan sulfate (DS)--were determined using a high-performance liquid chromatography method. The lateral menisci from the joints of animals injected with HA showed higher hexuronate and GAG levels than those of controls. This increase was mainly due to C-6-S, which had highest levels in the inner and middle meniscal zones. In addition, dermatan sulfate levels increased significantly in the middle and outer zones of the lateral menisci compared with the same zones of the meniscus from the saline-treated group. Collagen and C-O-S levels were not statistically different from those of controls. These data suggest that intraarticular administration of high-molecular-weight HA immediately after open total medial meniscectomy may help preserve the proteoglycans in the lateral meniscus remaining in the joint.
Delayed presentation of infection is a rare complication of anterior instrumentation and fusion for scoliosis. Three cases that followed the Dwyer procedure are reported. Pain was absent in these patients, but mild constitutional symptoms were present. An elevated erythrocyte sedimentation rate (ESR) is an important indicator of this complication. Two patients developed groin abscesses and sinuses as the hallmark of deep infection. Infection resolved after removal of instrumentation and local debridement.
A review of 35 patients > 60 years of age with odontoid fractures showed that a type II injury (Anderson and D'Alonso) was the most common fracture pattern (82% of cases). On the basis of mechanism of injury and sex incidence, we deduced that osteopenia is a contributory factor in the occurrence of odontoid fractures. A fall in a domestic setting was the cause in 53%. The peg was posteriorly displaced in 88% of type II fractures, and primary union occurred in 23%. The incidence of concomitant spinal cord injury with type II fractures was higher in older patients than it was in those < 60 years of age. The outcome for these patients was largely determined by their neurological status at presentation. Myelopathy as a late complication of nonunion was not observed in nine patients with an average follow-up of 21 months. The data suggest that vigorous attempts to secure both primary union and a sound arthrodesis for non-union are questionable in the elderly except in unusual circumstances.
Explore the source record for details and available documents.
A 5 x 5-mm anterolateral incision was made in the annulus fibrosus (AF) of lumbar discs of 16 sheep; four animals of similar age not operated on were used as controls. The experimental animals were sacrificed 2, 4, 6, 8, 12, and 18 months postoperatively (PO), and the incised and adjacent lumbar discs were collected. Discs were dissected into four zones: AF (zones 1 and 2) and nucleus pulposus (NP) (zones 3 and 4) corresponding to the half of the AF in which the cut was made and its opposite half, and the complementary halves of the NP. Each zone was analyzed for moisture, proteoglycan (PG), collagen, and noncollagenous protein (NCP) content. The PG extractability, aggregation, and hydrodynamic size were also examined. The NP of injured discs showed a significant loss of PGs and collagen 8 months PO, but NCP levels increased. In the incised discs, PG aggregation initially declined but recovered to within control values 6-8 months PO. The NP of discs adjacent to the incised disc also showed time-dependent changes in matrix components that included loss of collagen and PG; however, the AF matrix remained essentially uneffected. Double immunodiffusion studies indicated that a sizeable proportion of the NCPs present in the injured discs (but not the adjacent lumbar discs) were derived from serum.
Contagious bovine pleuropneumonia (CBPP), which is caused by Mycoplasma mycoides subspecies mycoides, is still a serious disease in some parts of the world. There is also a commonly occurring mycoplasma which is sufficiently related to the CBPP organism to bear the same name, even though this organism does not cause CBPP. Thus it is very important to be able to distinguish between these organisms and identify either with certainty. Fragments derived from M mycoides subspecies capri by restriction enzyme digestion of genomic DNA were cloned into the vector M13mp8. One resulting clone CAP-21, with a 1.5 kb insert was used as a probe in Southern hybridisation assays where genomic DNA was digested with the restriction endonuclease TaqI. This probe could differentiate a strain of M mycoides subspecies mycoides which does not cause CBPP. Subsequent tests on 14 other strains from cattle and goats showed that although they were isolated from diverse geographical areas, CAP-21 could clearly differentiate between these two types of M mycoides subspecies mycoides.
Serine proteinase inhibitory proteins (SPIs) were extracted from human disc tissues using 2 M GuHCl and subjected to CsCl density gradient ultracentrifugation. The SPIs recovered in the low buoyant density fractions (rho < or = 1.35 g/ml) were purified by a combination of gel-permeation, ion-exchange, trypsin affinity, and reverse-phase high performance chromatographies. Characterisation of the major disc SPI by polyacrylamide gel electrophoresis, isoelectric focussing, enzyme inhibition and pH stability studies indicated that this small molecular weight (12-14 kDa), highly basic (pI > 9.5), acid-stable but alkaline-labile protein possessed potent inhibitory activity against bovine pancreatic trypsin and chymotrypsin, and human leukocyte elastase and cathepsin G. Two-major and two-minor low molecular weight cationic SPI species were identified by reverse-phase HPLC. The predominant species was identical to a human articular cartilage SPI sharing amino terminal sequence homology with the mucus proteinase inhibitors (MPIs). It also cross-reacted with an antiserum to the MPIs and behaved identically to secretory leucocyte proteinase inhibitor (SLPI) when examined by reverse phase HPLC, and SDS PAGE. A higher molecular weight (54 kDa), anionic (pI approximately 4.6) SPI was also purified and identified as alpha 1-proteinase inhibitor (alpha 1-PI). Quantification of alpha 1-PI and the small molecular weight cationic disc inhibitors indicated that the latter were depleted in morphologically degenerate disc tissues while levels of alpha 1-PI were somewhat higher although a large proportion of the alpha 1-PI was inactive. A depletion of total SPI levels was evident overall in degenerate discs suggesting a functional role for these inhibitory proteins in the maintenance of IVD matrix homeostasis.
A gene probe, CAP-21, which demonstrated interrelationships between the members of the Mycoplasma mycoides cluster was developed. The probe easily differentiated mycoplasmas in this cluster by clear and predictable hybridization patterns in Southern blots and separated the cluster into four groups. Strains of M. mycoides subsp. mycoides which were capable of causing contagious bovine pleuropneumonia composed one group. Strains of M. mycoides subsp. mycoides which did not cause contagious bovine pleuropneumonia together with strains of M. mycoides subsp. capri composed the second group. Mycoplasma capricolum and the F38 mycoplasmas formed a third group, while the bovine group 7 mycoplasmas composed a separate, fourth group. Further support for the above grouping of the cluster was obtained when amplified DNA analogous to the probe from one representative strain of each of the cluster members was sequenced and these data were used to construct a phylogenic tree. Contagious caprine pleuropneumonia is recognized as an important disease, and the etiological agent of this disease is now known to be the F38 mycoplasma. The CAP-21 probe did not differentiate between M. capricolum and the closely related F38 mycoplasma. A second probe, F38-12, which was capable of distinguishing these two mycoplasmas was made.
Explore the source record for details and available documents.
This paper reviews the syndromes which affect the spinal column as a result of Paget's disease. These are back pain, spinal canal stenosis, paraplegia or paraparesis, sarcomatous transformation, intradiscal invasion, and extramedullary haemopoesis.
Explore the source record for details and available documents.