Warmblood fragile foal syndrome type 1 mutation (PLOD1 c.2032G>A) is not associated with catastrophic breakdown and has a low allele frequency in the Thoroughbred breed.

BACKGROUND: Catastrophic fractures are among the most common cause of fatalities in racehorses. Several factors, including genetics, likely contribute to increased risk for fatal injuries. A variant in the procollagen-lysine, 2-oxoglutarate 5-dioxygenase1 gene (PLOD1 c.2032G>A) was shown to cause Warmblood fragile foal syndrome type 1 (WFFS), a fatal recessive defect of the connective tissue. Screening of multiple horse breeds identified the presence of the WFFS allele in the Thoroughbred. PLOD1 is involved in cross-linking of collagen fibrils and thus could potentially increase the risk of catastrophic breakdown. OBJECTIVES: Estimate the frequency of the WFFS allele (PLOD1 c.2032G>A) and determine if it is a risk factor for catastrophic breakdown in the Thoroughbred. STUDY DESIGN: Case-control genetic study. METHODS: Genomic DNA from hair and/or tissue samples was genotyped for the WFFS allele. Fisher's Exact tests were performed to compare allele and carrier frequencies between the case cohort (catastrophic breakdown, n = 22) and several cohorts with no record of injury (n = 138 raced/trained at same track and season and n = 185 older than 7 years and raced during same season), nonracers (n = 92), and a random sample without consideration for racing history (n = 279). RESULTS: The frequency of the PLOD1 c.2032G>A variant in the Thoroughbred breed is low (1.2%). Seventeen of 716 Thoroughbreds tested were carriers (2.4%) and no WFFS homozygotes were detected. Only one catastrophic breakdown case carried the WFFS allele. No statistically significant difference in allele or carrier frequency was identified between case and control cohorts (P>0.05 in all comparisons performed). MAIN LIMITATIONS: This study evaluated cases from one single track. CONCLUSIONS: This study demonstrated that the PLOD1 c.2032G>A associated with WFFS is present at very low frequency in Thoroughbreds and is not a genetic risk factor for catastrophic breakdown.

Assessing the Acceptability of Science Operations Concepts and the Level of Mission Enhancement of Capabilities for Human Mars Exploration Extravehicular Activity.

The Biologic Analog Science Associated with Lava Terrains (BASALT) research project is investigating tools, techniques, and strategies for conducting Mars scientific exploration extravehicular activity (EVA). This has been accomplished through three science-driven terrestrial field tests (BASALT-1, BASALT-2, and BASALT-3) during which the iterative development, testing, assessment, and refinement of concepts of operations (ConOps) and capabilities were conducted. ConOps are the instantiation of operational design elements that guide the organization and flow of personnel, communication, hardware, software, and data products to enable a mission concept. Capabilities include the hardware, software, data products, and protocols that comprise and enable the ConOps. This paper describes the simulation quality and acceptability of the Mars-forward ConOps evaluated during BASALT-2. It also presents the level of mission enhancement and acceptability of the associated Mars-forward capabilities. Together, these results inform science operations for human planetary exploration.

Developing Intra-EVA Science Support Team Practices for a Human Mission to Mars.

During the BASALT research program, real (nonsimulated) geological and biological science was accomplished through a series of extravehicular activities (EVAs) under simulated Mars mission conditions. These EVAs were supported by a Mission Support Center (MSC) that included an on-site, colocated Science Support Team (SST). The SST was composed of scientists from a variety of disciplines and operations researchers who provided scientific and technical expertise to the crew while each EVA was being conducted (intra-EVA). SST management and organization developed under operational conditions that included Mars-like communication latencies, bandwidth constraints, and EVA plans that were infused with Mars analog field science objectives. This paper focuses on the SST workspace considerations such as science team roles, physical layout, communication interactions, operational techniques, and work support technology. Over the course of BASALT field deployments to Idaho and Hawai'i, the SST team made several changes of note to increase both productivity and efficiency. For example, new roles were added for more effective management of technical discussions, and the layout of the SST workspace evolved multiple times during the deployments. SST members' reflexive adjustments resulted in a layout that prioritized face-to-face discussions over face-to-data displays, highlighting the importance of interpersonal communication during SST decision-making. In tandem with these workspace adjustments, a range of operational techniques were developed to help the SST manage discussions and information flow under time pressure.

Estimated frequency of the canine hyperuricosuria mutation in different dog breeds.

BACKGROUND: Hyperuricosuria is a condition that predisposes dogs to urate urolithiasis. A mutation that causes canine hyperuricosuria was previously identified in 3 unrelated dog breeds. The occurrence of the mutation in additional breeds was not determined. HYPOTHESIS/OBJECTIVES: Identify additional breeds that have the hyperuricosuria mutation and estimate the mutant allele frequency in those breeds. ANIMALS: Three thousand five hundred and thirty dogs from 127 different breeds were screened for the hyperuricosuria mutation. METHODS: DNA samples were genotyped by pyrosequencing and allele-specific polymerase chain reaction methods. RESULTS: Mutant allele frequencies that range from 0.001 to 0.15 were identified in the American Staffordshire Terrier, Australian Shepherd, German Shepherd Dog, Giant Schnauzer, Parson (Jack) Russell Terrier, Labrador Retriever, Large Munsterlander, Pomeranian, South African Boerboel, and Weimaraner breeds. CONCLUSIONS AND CLINICAL IMPORTANCE: The hyperuricosuria mutation has been identified in several unrelated dog breeds. The mutant allele frequencies vary among breeds and can be used to determine an appropriate breeding plan for each breed. A DNA test is available and may be used by breeders to decrease the mutant allele frequency in breeds that carry the mutation. In addition, veterinarians may use the test as a diagnostic tool to identify the cause of urate urolithiasis.

Analysis of genetic variation in 28 dog breed populations with 100 microsatellite markers.

Dog breeds were created by man choosing for select phenotypic traits such as size, shape, coat color, conformation, and behavior. Rigorous phenotypic selection likely resulted in a loss of genetic information. The present study extends previous dog population observations by assessing the genotypic variation within and across 28 breeds representing the seven recognized breed groups of the American Kennel Club (AKC). One hundred autosomal microsatellite markers distributed across the canine genome were used to examine variation within breeds. Resulting breed-specific allele frequencies were then used in an attempt to elucidate phylogeny and genetic distances between breeds. While the set of autosomal microsatellites was useful in describing genetic variation within breeds, establishing the genetic relatedness between breeds was less conclusive. A more accurate determination of breed phylogeny will likely require the use of single-nucleotide polymorphisms (SNPs).

PCR multiplexed microsatellite panels to expedite canine genetic disease linkage analysis.

Modern dog breeds possess large numbers of genetic diseases for which there are currently few candidate genes or diagnostic tests. Linkage of a microsatellite marker to a disease phenotype is often the only available tool to aid in the development of screening tests for disease carriers. Detection of linkage to a specific disease phenotype requires screening of large numbers of markers across known affected and unaffected animals. To establish high throughput genome scanning this study placed 100 canine microsatellite markers, arranged by fragment size and fluorescent dye label, into 12 PCR multiplexed panels. The highest degree of multiplexing was 11 markers per panel while the lowest was five markers per panel; each panel was run in one gel lane on automated DNA sequencers. Selection of the markers was based upon chromosomal or linkage group locations, degree of polymorphism, PCR multiplex compatibility and ease of interpretation. The marker set has an average spacing of 22.25 centiMorgan (cM). Marker polymorphism was evaluated across 28 American Kennel Club (AKC) recognized breeds. The utility of buccal swab vs. blood samples was also validated in this study as all template DNA was derived from swabs obtained and submitted by participating dog breeders and owners. The PCR multiplexed microsatellite panels and sampling method described in this report will provide investigators with a cost effective and expedient means of pursuing linkage studies of specific canine genetic diseases.

Making dollars out of DNA. The first major patent in biotechnology and the commercialization of molecular biology, 1974-1980.

In 1973-1974 Stanley N. Cohen of Stanford and Herbert W. Boyer of the University of California, San Francisco, developed a laboratory process for joining and replicating DNA from different species. In 1974 Stanford and UC applied for a patent on the recombinant DNA process; the U.S. Patent Office granted it in 1980. This essay describes how the patenting procedure was shaped by the concurrent recombinant DNA controversy, tension over the commercialization of academic biology, governmental deliberations over the regulation of genetic engineering research, and national expectations for high technology as a boost to the American economy. The essay concludes with a discussion of the patent as a turning point in the commercialization of molecular biology and a harbinger of the social and ethical issues associated with biotechnology today.

Results of surgery for spinal stenosis adjacent to previous lumbar fusion.

The literature provides little data to guide surgical management of spinal stenosis adjacent to previous lumbar fusion. Thirty-three consecutive patients who had surgical decompression for spinal stenosis at the lumbar segments adjacent to a previous lumbar fusion were studied. The mean interval between fusion and the adjacent segment surgery was 94 months. Of the 33 patients, 26 were followed for 3-14 years (mean: 5 years) after adjacent segment surgery and were clinically evaluated and independently completed an outcome questionnaire. Of the 26 patients, 15 rated their outcome as completely satisfactory, 6 were neutral toward the surgery, and 5 considered their surgery a failure. The surgery was generally effective at improving or relieving lower extremity neurogenic claudication. The strongest independent predictive factor of patient dissatisfaction was ongoing postoperative low back pain (r = 0.7, p = 0.001). A higher back pain score at follow-up was associated with continued narcotic use (p = 0.001) and decreased ability to perform activities of daily living (p = 0.05). Six patients required further lumbar surgery during the follow-up period. This study provides the longest published follow-up data of surgical results for symptomatic spinal stenosis adjacent to a previously asymptomatic lumbar fusion.

Effect of standard total knee arthroplasty surgical dissection on human patellar blood flow in vivo: an investigation using laser Doppler flowmetry.

We examined the in vivo alterations of human patellar bone blood flow that occur with surgical dissection of the extensor mechanism during total knee arthroplasty. A laser doppler probe was used to measure central patellar blood flow at baseline after quadriceps tenotomy, after partial fat pad excision, after lateral release, and after completion of the lateral release with superolateral geniculate sacrifice. The initial quadriceps tenotomy and medial arthrotomy decreased patellar vascularity to 60.4% of baseline. Fat pad resection initiated another 10.4% decline. The lateral release resulted in a patellar vascularity that was 43.6% of baseline. Finally, the loss of superolateral geniculate inflow reduced the patellar flow to 30.61% of baseline.

Translaminar lumbar epidural endoscopy: technique and clinical results.

To provide baseline outcome data for a new lumbar microinvasive diskectomy done with standard arthroscopic instrumentation, we retrospectively reviewed the cases of 190 patients. All patients were assessed by a modified MacNab outcome classification with a minimum of a 2-year follow-up. All complications of this procedure were reported as well. No previous outcome data are available for this procedure, since it has been done primarily at one center, by the same surgeon, using his previously reported techniques. Results were good or excellent in 175 patients and fair or poor in 15. Complications were not severe and were easily remedied. This success rate is comparable to rates reported for other minimally invasive operations on the lumbar spine. This new technique of minimally invasive lumbar spine surgery provides minimal morbidity and a long-term outcome comparable to that of other standard procedures. The added benefits of using standard arthroscopic instrumentation are discussed.

Failed anterior cervical discectomy and arthrodesis. Analysis and treatment of thirty-five patients.

Thirty-five patients were managed operatively after failure of an anterior cervical discectomy and arthrodesis. Failure was classified as the absence of fusion without deformity but with neck pain or radiculopathy, or both; the absence of fusion after anterior or posterior dislodgment of the graft; or kyphosis due to collapse of the graft or to an unrecognized posterior soft-tissue injury. Twenty-three patients had failure of the arthrodesis without deformity (with neck pain only, neck and arm pain, radiculopathy, or myelopathy). Four patients had dislodgment of the graft; in two of them the graft migrated anteriorly after a multilevel Robinson arthrodesis, and in two it migrated posteriorly after a Cloward arthrodesis. Eight patients had a failure because of a kyphotic deformity. Five of them had had a Cloward arthrodesis; one, a discectomy; and two, a Robinson arthrodesis. Six had received allograft bone. Operative treatment of the pseudarthrosis consisted of repeat resection of the disc space in the area of the failed arthrodesis followed by repeat anterior Robinson arthrodesis with decompression of the nerve root if the patient had radiculopathy. It consisted of anterior corpectomy or vertebral-body resection and strut-grafting with reduction of the deformity if the patient had migration of the graft and kyphosis. The reoperations were performed four months to fourteen years (average, thirty-two months) after the initial operation. The duration of follow-up after the second operation averaged forty-four months (range, twenty-four to 216 months). The result was excellent for twenty-nine patients, good for one, fair for four, and poor for one. We concluded that, in patients who have persistent symptoms after an anterior cervical arthrodesis, an excellent result can be achieved with repeat anterior decompression and autogenous bone-grafting.

Translaminar lumbar epidural endoscopy: anatomy, technique, and indications.

This article describes a new technique to achieve access to the epidural space via a direct posterior portal. This minimally invasive technique allows treatment of disc protrusions and extrusions with full visualization and minimal dissection of the paraspinal musculature. Hemostasis, visualization, and triangulation is performed with standard arthroscopic instrumentation. The anatomy of, indications for, and advantages of this techniques are described.

Shared phenotypic expression of osteoblasts and chondrocytes in fracture callus.

Endochondral ossification in fracture healing of rats at 4, 8, 11, 14, and 21 days was analyzed using immunological and molecular probes for markers of the chondrocyte and osteoblast phenotype. These markers were osteocalcin, type I and type II collagen, including the probes homologous to the alternatively spliced forms of alpha 1 type II collagen, type IIA and type IIB. Histologic examination was performed on serial sections of the same tissue blocks to correlate cellular morphology with the immunohistochemical and in situ hybridization findings. At the junction of the cartilaginous and osseous tissue, an overlap of phenotype and morphology was noted. At the 8-day time point, the cells with chondrocyte morphology expressed intracellular message for osteocalcin and type I collagen. Immunohistochemical analysis of these cells also demonstrated intracellular osteocalcin. However, high levels of the type IIA collagen mRNA, which has previously been associated with less differentiated mesenchymal precursor cells, were expressed in both chondrocytes and osteoblasts. At the later time point (21 days) there was a substantial decrease in the number of cells displaying shared phenotypic characteristics. In situ hybridization and immunohistochemistry have permitted identification of an overlapping or shared phenotype in osteoblasts and chondroblasts in fracture callus. The findings raise important questions regarding the possible plasticity of mesenchymal cell phenotypes within the dynamic environment of fracture healing. Additional examination of these issues will further define factors involved in origin, differentiation, and maturation of bone and cartilage cells.

Atrophy of the proximal part of the femur after total hip arthroplasty without cement. A quantitative comparison of cobalt-chromium and titanium femoral stems with use of dual x-ray absorptiometry.

The purpose of this study was to compare the density of periprosthetic bone about titanium and cobalt-chromium stems that had been inserted without cement. The analysis was done, three to four years after a total hip arthroplasty, in a retrospectively matched cohort of thirty patients. Fifteen patients had a stem that was collarless, proximally coated, and made of titanium; the other fifteen had a stem of similar design that was made of cobalt-chromium. The criteria for selection in the study included an excellent clinical and radiographic result and separately calculated modified Harris and Mayo hip scores of more than 94 points. All stems had radiographic evidence of osseous ingrowth. A comparison of the bone-mineral density about the two different types of stem with dual-energy x-ray absorptiometry revealed a significant difference only along the calcar of the femur. There was no significant difference about the remaining, preponderant portion of the proximal part of the femur. Our data suggest that the difference in the modulus of elasticity between the two types of stem had little effect on the loss of bone-mineral density in most of the proximal part of the femur after arthroplasty without cement.

The fate of anterior vertebral bone grafts in patients irradiated for neoplasm.

Perioperative irradiation is often used with anterior decompression and vertebral interbody fusion for the treatment of spinal neoplasms, yet little is known regarding the healing potential of these grafts. This review of 25 patients with neoplasm who had anterior vertebrectomy, bone strut insertion, and perioperative irradiation was performed to look specifically for evidence of radiographic fusion as determined by plain radiographs, tomograms, or computed tomography reconstruction. Four of 25 patients (16%) were judged to have a pseudarthrosis. All four pseudarthrosis patients but only four of 21 fusion patients had 4000 cg or more of irradiation, a statistically significant difference. There was a trend for lumbar lesions to have a higher risk for nonunion. Concomitant posterior stabilization did not necessarily prevent pseudarthrosis. Two iliac strut grafts with a pseudoarthrosis developed late fracture and one went on to collapse into kyphosis. The pseudarthrosis rate of anterior vertebral strut grafts in the face of irradiation for tumor is relatively high, and late graft fracture can occur if pseudarthrosis develops. Probable risk factors include irradiation greater than 4000 cg and lumbar lesions. Posterior stabilization to protect the graft may be warranted in the highest-risk patients.

A collarless cobalt-chrome femoral component in uncemented total hip arthroplasty. Five- to eight-year follow-up.

We implanted 57 uncemented cobalt-chrome porous-coated collarless femoral components into 51 patients (mean age 49 years). At review, five to eight years postoperatively, good or excellent results were recorded in 70% by the Mayo Clinic hip evaluation and in 84% by the Harris hip score. Revision for aseptic loosening of the femoral stem was necessary in only one hip. Thigh pain diminished with time and was present in only two hips at the time of review. Endosteal bone formation was seen at the junction of the smooth and the porous segments of the stem in 94% of hips and in 60% it continued after three years. In 90% of hips, proximal femoral atrophy did not progress after three years. Discontinuous radiolucent lines were seen around 30% of stems, most commonly in zones I, IV and VII. They were not progressive in 94% and their presence did not correlate with the clinical outcome.

Nonradioactive in situ hybridization using digoxigenin-labeled oligonucleotides. Applications to musculoskeletal tissues.

We have optimized a technique for in situ localization of specific mRNAs using digoxigenin-11-dUTP-labeled oligonucleotide probes. DNA probes were synthesized for type I and type II collagen as well as transforming growth factor-beta 1 and 2 (TGF beta 1 and TGF beta 2). Control experiments, such as competitive inhibition, nonsense sequence hybridization, and RNAse digestion all indicated that the technique was highly sensitive and specific. In sections of growth plate, type II collagen mRNA was predominantly expressed in the lower proliferative and upper hypertrophic zone, whereas chondrocytes in articular cartilage stained equally. These techniques then were applied to sections cut from archival pathology specimens of musculoskeletal tissues. Primitive chondrocytes in a chondrosarcoma expressed type I and type II collagen mRNA, but did not stain with the nonsense probe. Sections from an osteosarcoma, an aneurysmal bone cyst, and a neurofibroma also were investigated. The ability to use chemically synthesized oligonucleotide probes, the high resolution, and the short development times possible with this in situ procedure makes this technique appealing for applied research into the gene expression of normal and pathologic cellular events.