| 4161. |
- Pruneski, J. A., et al.
(författare)
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Natural language processing: using artificial intelligence to understand human language in orthopedics
- 2023
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Ingår i: Knee Surgery Sports Traumatology Arthroscopy. - : Springer Science and Business Media LLC. - 0942-2056 .- 1433-7347. ; 31:4, s. 1203-1211
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Tidskriftsartikel (refereegranskat)abstract
- Natural language processing (NLP) describes the broad field of artificial intelligence by which computers are trained to understand and generate human language. Within healthcare research, NLP is commonly used for variable extraction and classification/cohort identification tasks. While these tools are becoming increasingly popular and available as both open-source and commercial products, there is a paucity of the literature within the orthopedic space describing the key tasks within these powerful pipelines. Curation and navigation of the electronic medical record are becoming increasingly onerous, and it is important for physicians and other healthcare professionals to understand potential methods of harnessing this large data resource. The purpose of this study is to provide an overview of the tasks required to develop an NLP pipeline for orthopedic research and present recent examples of successful implementations.
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| 4162. |
- Pruneski, J. A., et al.
(författare)
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Supervised machine learning and associated algorithms: applications in orthopedic surgery
- 2023
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Ingår i: Knee Surgery Sports Traumatology Arthroscopy. - : Springer Science and Business Media LLC. - 0942-2056 .- 1433-7347. ; 31:4, s. 1196-1202
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Tidskriftsartikel (refereegranskat)abstract
- Supervised learning is the most common form of machine learning utilized in medical research. It is used to predict outcomes of interest or classify positive and/or negative cases with a known ground truth. Supervised learning describes a spectrum of techniques, ranging from traditional regression modeling to more complex tree boosting, which are becoming increasingly prevalent as the focus on "big data" develops. While these tools are becoming increasingly popular and powerful, there is a paucity of literature available that describe the strengths and limitations of these different modeling techniques. Typically, there is no formal training for health care professionals in the use of machine learning models. As machine learning applications throughout medicine increase, it is important that physicians and other health care professionals better understand the processes underlying application of these techniques. The purpose of this study is to provide an overview of commonly used supervised learning techniques with recent case examples within the orthopedic literature. An additional goal is to address disparities in the understanding of these methods to improve communication within and between research teams.
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| 4163. |
- Przkora, René, et al.
(författare)
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Operative treatment of unstable odontoid fractures in the geriatric population
- 2006
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Ingår i: Topics in Spinal Cord Injury Rehabilitation. - 1082-0744 .- 1945-5763. ; 12:2, s. 12-19
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Tidskriftsartikel (refereegranskat)abstract
- Background: Odontoid fractures, often in combination with C1 fractures, are a common fracture of the cervical spine in geriatric patients. The optimal treatment of this fracture in this patient population is often controversial. We report the surgical outcome of unstable type II odontoid fractures in the elderly. Method: 8 patients (median age, 80.5 years; range, 72-93) with unstable type II odontoid fractures according to the Anderson and d'Alonzo classification were included in this prospective study. 2 patients sustained a C1 fracture (1 had an unstable type III fracture according to the Gehweiler classification, and 1 had a stable type III fracture). There were no neurological complications. All patients were classified as ASA class III. 7 patients were treated with anterior odontoid double-screw compression osteosynthesis followed by a firm neck support for 6 weeks. 1 patient with an unstable C1 and C2 fracture was treated with an occipital cervical (C2) fusion in combination with a C1-C2 fusion according to Magerl technique. Follow-up was 18 months. Results: No deaths occurred during the study period. All patients demonstrated fracture healing at followup. Median length of hospital stay was 31.4 days (range, 16-64). Preexisting comorbidities complicated final outcome in 2 patients, both of whom received a temporary tracheostomy for respiratory failure. Conclusion: Type II odontoid fracture healing can occur predictably with anterior double-screw compression osteosynthesis. The outcome in this patient population may be complicated by preexisting medical comorbidities.
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| 4164. |
- Pulkkinen, Hertta, et al.
(författare)
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Cellulose sponge as a scaffold for cartilage tissue engineering.
- 2006
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Ingår i: Bio-medical materials and engineering. - : IOS Press. - 0959-2989 .- 1878-3619. ; 16:4 Suppl, s. S29-S35
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Tidskriftsartikel (refereegranskat)abstract
- One goal of functional tissue engineering is to manufacture scaffolds infiltrated with chondrocytes which are suitable for transplantation into the lesion areas of articular cartilage. Various research strategies are used to fabricate cartilage transplants which would have the correct phenotype, contain enough extracellular matrix components, and have structural and biomechanical properties equivalent to normal articular cartilage. We have investigated the suitability of viscose cellulose sponges as a scaffold for cartilage tissue engineering. The sponges were tested alone, or with recombinant human type II collagen cross-linked inside the material. Scanning electron microscopy and confocal microscopy were used to study the structure of the scaffold during four weeks of cultivation. Cellulose and cellulose/recombinant type II collagen sponges were biocompatible for at least four weeks in cultivation, and gradual filling of the scaffold was observed. However, the constructs remained soft during the observation period, and were devoid of extracellular matrix composition typical for normal articular cartilage.
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| 4165. |
- Pulkkinen, Hertta, et al.
(författare)
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Engineering of cartilage in recombinant human type II collagen gel in nude mouse model in vivo.
- 2010
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584 .- 1522-9653. ; 18:8, s. 1077-1087
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Our goal was to test the recombinant human type II collagen (rhCII) material as a gel-like scaffold for chondrocytes in a nude mouse model in vivo.DESIGN: Isolated bovine chondrocytes (6x10(6)) were seeded into rhCII gels (rhCII-cell) and injected subcutaneously into the backs of nude mice. For comparison, chondrocytes (6x10(6)) in culture medium (Med-cell) and cell-free rhCII gels (rhCII-gel) were similarly injected (n=24 animals, total of three injections/animal). After 6 weeks, the tissue constructs were harvested and analyzed.RESULTS: Chondrocytes with or without rhCII-gel produced white resilient tissue, which in histological sections had chondrocytes in lacunae-like structures. Extracellular matrix stained heavily with toluidine blue stain and had strongly positive collagen type II immunostaining. The tissue did not show any evidence of vascular invasion or mineralization. The cell-free rhCII-gel constructs showed no signs of cartilage tissue formation. Cartilage tissue produced by Med-cell was thin and macroscopically uneven, while the rhCII-cell construct was smooth and rounded piece of neotissue. RhCII-cell constructs were statistically thicker than Med-cell ones. However, no statistical differences were found between the groups in terms of glycosaminoglycan (GAG) content or biomechanical properties.CONCLUSIONS: These results show that rhCII-gel provides good expansion and mechanical support for the formation of cartilage neotissue. RhCII material may allow favorable conditions in the repair of chondral lesions.
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| 4166. |
- Pulkkinen, Hertta, et al.
(författare)
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Recombinant human type II collagen as a material for cartilage tissue engineering.
- 2008
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Ingår i: International Journal of Artificial Organs. - : Wichtig Editore Srl. - 0391-3988 .- 1724-6040. ; 31:11, s. 960-969
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Collagen type II is the major component of cartilage and would be an optimal scaffold material for reconstruction of injured cartilage tissue. In this study, the feasibility of recombinant human type II collagen gel as a 3-dimensional culture system for bovine chondrocytes was evaluated in vitro.METHODS: Bovine chondrocytes (4x106 cells) were seeded within collagen gels and cultivated for up to 4 weeks. The gels were investigated with confocal microscopy, histology, and biochemical assays.RESULTS: Confocal microscopy revealed that the cells maintained their viability during the entire cultivation period. The chondrocytes were evenly distributed inside the gels, and the number of cells and the amount of the extracellular matrix increased during cultivation. The chondrocytes maintained their round phenotype during the 4-week cultivation period. The glycosaminoglycan levels of the tissue increased during the experiment. The relative levels of aggrecan and type II collagen mRNA measured with realtime polymerase chain reaction (PCR) showed an increase at 1 week.CONCLUSION: Our results imply that recombinant human type II collagen is a promising biomaterial for cartilage tissue engineering, allowing homogeneous distribution in the gel and biosynthesis of extracellular matrix components.
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| 4167. |
- Pulkkinen, Hertta, et al.
(författare)
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Repair of osteochondral defects with recombinant human type II collagen gel and autologous chondrocytes in rabbit
- 2013
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier. - 1063-4584 .- 1522-9653. ; 21:3, s. 481-490
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Tidskriftsartikel (refereegranskat)abstract
- SummaryObjectiveRecombinant human type II collagen (rhCII) gels combined with autologous chondrocytes were tested as a scaffold for cartilage repair in rabbits in vivo.MethodAutologous chondrocytes were harvested, expanded and combined with rhCII-gel and further pre-cultivated for 2 weeks prior to transplantation into a 4 mm diameter lesion created into the rabbit's femoral trochlea (n = 8). Rabbits with similar untreated lesions (n = 7) served as a control group.ResultsSix months after the transplantation the repair tissue in both groups filled the lesion site, but in the rhCII-repair the filling was more complete. Both repair groups also had high proteoglycan and type II collagen contents, except in the fibrous superficial layer. However, the integration to the adjacent cartilage was incomplete. The O'Driscoll grading showed no significant differences between the rhCII-repair and spontaneous repair, both representing lower quality than intact cartilage. In the repair tissues the collagen fibers were abnormally organized and oriented. No dramatic changes were detected in the subchondral bone structure. The repair cartilage was mechanically softer than the intact tissue. Spontaneously repaired tissue showed lower values of equilibrium and dynamic modulus than the rhCII-repair. However, the differences in the mechanical properties between all three groups were insignificant.ConclusionWhen rhCII was used to repair cartilage defects, the repair quality was histologically incomplete, but still the rhCII-repairs showed moderate mechanical characteristics and a slight improvement over those in spontaneous repair. Therefore, further studies using rhCII for cartilage repair with emphasis on improving integration and surface protection are required.
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| 4168. |
- Pulliainen, Outi, et al.
(författare)
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Poly-L-D-lactic acid scaffold in the repair of porcine knee cartilage lesions.
- 2007
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Ingår i: Tissue engineering. - : Mary Ann Liebert Inc. - 1076-3279 .- 1557-8690. ; 13:6, s. 1347-55
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Tidskriftsartikel (refereegranskat)abstract
- Articular cartilage injuries cause a major clinical problem because of the negligible repair capacity of cartilage. Autologous chondrocyte transplantation is a surgical method developed to repair cartilage lesions. In the operation, cartilage defect is covered with a periosteal patch and the suspension of cultured autologous chondrocytes is injected into the lesion site. The method can form good repair tissue, but new techniques are needed to make the operation easier and to increase the postoperative biomechanical properties of the repair tissue. In this study, we investigated poly-L,D-lactic acid (PLDLA) scaffolds alone or seeded with autologous chondrocytes in the repair of circular 6-mm cartilage lesions in immature porcine knee joints. Spontaneous repair was used as a reference. Histologic evaluation of the repair tissue showed that spontaneous repair exhibited higher scores than either PLDLA scaffold group (with or without seeded chondrocytes). The scaffold material was most often seen embedded in the subchondral bone underneath the defect area, probably because of the hardness of the PLDLA material. However, some of the cell-seeded and nonseeded scaffolds contained cartilaginous tissue, suggesting that invasion of mesenchymal cells inside nonseeded scaffolds had occurred. Hyaluronan deposited in the scaffold had possibly acted as a chemoattractant for the cell recruitment. In conclusion, the PLDLA scaffold material used in this study was obviously mechanically too hard to be used for cartilage repair in immature animals.
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| 4169. |
- Puntillo, Filomena, et al.
(författare)
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Pathophysiology of musculoskeletal pain : a narrative review
- 2021
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Ingår i: Therapeutic Advances in Musculoskeletal Disease. - : Sage Publications. - 1759-7218 .- 1759-720X. ; 13, s. 1-12
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Forskningsöversikt (refereegranskat)abstract
- Musculoskeletal pain (excluding bone cancer pain) affects more than 30% of the global population and imposes an enormous burden on patients, families, and caregivers related to functional limitation, emotional distress, effects on mood, loss of independence, and reduced quality of life. The pathogenic mechanisms of musculoskeletal pain relate to the differential sensory innervation of bones, joints, and muscles as opposed to skin and involve a number of peripheral and central nervous system cells and mediators. The interplay of neurons and non-neural cells (e.g. glial, mesenchymal, and immune cells) amplifies and sensitizes pain signals in a manner that leads to cortical remodeling. Moreover, sex, age, mood, and social factors, together with beliefs, thoughts, and pain behaviors influence the way in which musculoskeletal pain manifests and is understood and assessed. The aim of this narrative review is to summarize the different pathogenic mechanisms underlying musculoskeletal pain and how these mechanisms interact to promote the transition from acute to chronic pain.
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| 4170. |
- Puustjärvi, Kaija, et al.
(författare)
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Flat bed scanner in the quantitative assay of 35SO4-incorporation by X-ray film autoradiography of intervertebral disc sections.
- 1993
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Ingår i: Histochemistry. - : Springer. - 0301-5564. ; 99:1, s. 67-73
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Tidskriftsartikel (refereegranskat)abstract
- A rapid quantitation of proteoglycan synthesis distribution in intervertebral disc and endplates is described. Tissue blocks of disc (C7-Th1) in the midsagittal plane from ten female beagles were incubated in the presence of 35SO4 and prepared as histological slides. For comparison, sulphate incorporation rates in the C5-C6 discs were assayed by liquid scintillation. Autoradiographic film exposed against the labelled sections was developed and digitized for image analysis using a 256 grey level flat bed table scanner connected to a microcomputer. The film density versus dpm (disintegrations per minute) calibration was performed using a set of 35SO4-labelled glycosaminoglycan standards applied on the same film. Since section thickness, dpm calibration of the film density and the specific activity of sulphate in the medium were known, the incorporations per tissue volume could be calculated. The average incorporation rates of the anterior and posterior annulus fibrosus, nucleus pulposus and vertebral endplates were 5.2 +/- 0.9, 5.2 +/- 0.8, 4.5 +/- 0.6 and 4.1 +/- 0.8 pmol/mm3 per h (+/- SE, n = 10), respectively and closely corresponded to those obtained by liquid scintillation. This method offers a convenient and reproducible way to measure the rate of proteoglycan synthesis in large tissue sections but also in thin cartilaginous tissues such as the vertebral endplate.
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