Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

结节病易误诊,据王洪武等~([1])收集国内18篇关于此病误诊的文献,误诊率高达63.2%,当然有误诊就会有误治,如孙永昌等~([2])报道26例结节病在影像学检查诊断的第一印象中拟诊结核5例,其中就有2例完成规范的抗结核治疗,为此应引起临床对本病诊治的重视。

Sarcoidosis

Articular cartilage was predicted to be one of the first tissues to successfully be regenerated, but this proved incorrect In contrast, bone (but also vasculature and cardiac tissues) has seen numerous successful reparative approaches, despite consisting of multiple cell and tissue types and, thus, possessing more complex design requirements Here, we use bone-regeneration successes to highlight cartilage-regeneration challenges: such as selecting appropriate cell sources and scaffolds, creating biomechanically suitable tissues, and integrating to native tissue We also discuss technologies that can address the hurdles of engineering a tissue possessing mechanical properties that are unmatched in human-made materials and functioning in environments unfavorable to neotissue growth

/pdf/unlike-bone-cartilage-regeneration-remains-elusive-1v15bd07dw.pdf

Unlike Bone, Cartilage Regeneration Remains Elusive

This review analyzes the literature of bone grafts and introduces tissue engineering as a strategy in this field of orthopedic surgery. We evaluated articles concerning bone grafts; analyzed characteristics, advantages, and limitations of the grafts; and provided explanations about bone-tissue engineering technologies. Many bone grafting materials are available to enhance bone healing and regeneration, from bone autografts to graft substitutes; they can be used alone or in combination. Autografts are the gold standard for this purpose, since they provide osteogenic cells, osteoinductive growth factors, and an osteoconductive scaffold, all essential for new bone growth. Autografts carry the limitations of morbidity at the harvesting site and limited availability. Allografts and xenografts carry the risk of disease transmission and rejection. Tissue engineering is a new and developing option that had been introduced to reduce limitations of bone grafts and improve the healing processes of the bone fractures and defects. The combined use of scaffolds, healing promoting factors, together with gene therapy, and, more recently, three-dimensional printing of tissue-engineered constructs may open new insights in the near future.

/pdf/bone-regenerative-medicine-classic-options-novel-strategies-3fz7aanv1p.pdf

Bone regenerative medicine: classic options, novel strategies, and future directions

Ca(2+) is an essential ion in all organisms, where it plays a crucial role in processes ranging from the formation and maintenance of the skeleton to the temporal and spatial regulation of neuronal function. The Ca(2+) balance is maintained by the concerted action of three organ systems, including the gastrointestinal tract, bone, and kidney. An adult ingests on average 1 g Ca(2+) daily from which 0.35 g is absorbed in the small intestine by a mechanism that is controlled primarily by the calciotropic hormones. To maintain the Ca(2+) balance, the kidney must excrete the same amount of Ca(2+) that the small intestine absorbs. This is accomplished by a combination of filtration of Ca(2+) across the glomeruli and subsequent reabsorption of the filtered Ca(2+) along the renal tubules. Bone turnover is a continuous process involving both resorption of existing bone and deposition of new bone. The above-mentioned Ca(2+) fluxes are stimulated by the synergistic actions of active vitamin D (1,25-dihydroxyvitamin D(3)) and parathyroid hormone. Until recently, the mechanism by which Ca(2+) enter the absorptive epithelia was unknown. A major breakthrough in completing the molecular details of these pathways was the identification of the epithelial Ca(2+) channel family consisting of two members: TRPV5 and TRPV6. Functional analysis indicated that these Ca(2+) channels constitute the rate-limiting step in Ca(2+)-transporting epithelia. They form the prime target for hormonal control of the active Ca(2+) flux from the intestinal lumen or urine space to the blood compartment. This review describes the characteristics of epithelial Ca(2+) transport in general and highlights in particular the distinctive features and the physiological relevance of the new epithelial Ca(2+) channels accumulating in a comprehensive model for epithelial Ca(2+) absorption.

https://www.physiology.org/doi/pdf/10.1152/physrev.00003.2004

Calcium Absorption Across Epithelia

Surgical Treatment Options for the Diabetic Charcot Midfoot Deformity

The purpose of the current prospective study was to determine the midterm results of 68 total ankle replacements with the Scandinavian Total Ankle Replacement (S.T.A.R.) prosthesis. The 65 patients (34 women and 31 men; mean age at surgery, 56.1 years [range, 22-85 years]) were assessed clinically and radiologically after 3.7 years (range, 2.4-6.2 years). Thirty-five patients (54%) were totally pain-free. The overall clinical score was graded as excellent or good in 67 ankles. The American Orthopaedic Foot and Ankle Society hindfoot score improved from 24.7 points (range, 3-44 points) preoperatively to 84.3 points (range, 44-100 points) at followup. Three patients (three ankles, 4.4%) had a ballooning bone lysis on the tibial side. Despite prophylaxis, periarticular hypertrophic bone formation was seen in 43 ankles (63%; 42 patients), associated with a decrease of dorsiflexion and plantar flexion. Nine ankles (13%; nine patients) had revision surgery because of problems with the components and 14 ankles (21%; 14 patients) had secondary or additional operations. All revision or secondary surgeries were successful, and no ankle had to be converted to an ankle arthrodesis. The early experience with the S.T.A.R. ankle implant is encouraging, although we have encountered more complications and potential problems than previously reported.

Scandinavian Total Ankle Replacement: A 3.7-year average followup of 65 patients : Total ankle arthroplasty

Tibiotalocalcaneal (TTC) arthrodesis can provide ankle stability and shows promising results as a salvage procedure even in cases with severe bone loss at the ankle. Correct hindfoot and ankle alignment seems important in these cases to achieve adequate hindfoot stability and adequate pain relief. Especially in failed total ankle replacement, failed ankle arthrodesis, or cases of severe bone loss (eg, talectomy), revision surgery is challenging. In this technical tip we describe a new method using an autologous fibula augmentation in combination with an intramedullary hindfoot nail. The equal-sized pieces of the distal fibula are inserted in a circular array into the defect area, providing biomechanical stability and filling of the bony defect. The equal-sized fibula fragments are harvested from the ipsilateral fibula and placed in a vertical pillar technique around the hindfoot nail (Figure 1).

Tibiotalocalcaneal Arthrodesis With an Intramedullary Hindfoot Nail and Pillar Fibula Augmentation: Technical Tip.

According to current experiences, hallux sesamoid non-unions of athletic patients frequently do not respond toconservative therapy. Different surgical approaches havebeen introduced to cure the small, but debilitating, bonefracture. Most commonly, total sesamoid bone excisionis used. Despite good outcome, a constant rate of hallucaldeviations (10%Y20% of cases) is reported. In addition,open surgery with meticulous reconstruction of the flexorhallucis brevis tendon is mandatory to achieve goodresults. The following article describes an alternativemethod with percutaneous screw fixation of sesamoidbone nonunions. The procedure uses a cannulated com-pression screw. Postoperative management encompassesfull weight bearing as tolerated in stiff-sole shoes for6 weeks; no sutures will have to be removed becausewound closure is done with a sterile strip. Gradual returnto full level of activity is allowed after constant reductionof the fracture is documented at the 6-week follow-up.Keywords: sesamoid fracture nonunion, bipartite, screwfixation, athlete, deformity

Victor Valderrabano

Papers

Surgical Treatment Options for the Diabetic Charcot Midfoot Deformity

Scandinavian Total Ankle Replacement: A 3.7-year average followup of 65 patients : Total ankle arthroplasty

Tibiotalocalcaneal Arthrodesis With an Intramedullary Hindfoot Nail and Pillar Fibula Augmentation: Technical Tip.

Percutaneous Fixation of Hallux Sesamoid Fractures

Spacer usage in prosthetic joint infections does not influence infect resolution: Retrospective analysis of 120 joints with two-stage exchange