Living organisms have homochiral L-amino acids in proteins and homochiral D-mononucleotides in nucleic acids. The chemical evolutionary process to protein homochirality has been discussed for many years. Although many scenarios have been proposed for homochirality in the monomeric compounds, homochirality in amino acids and mononucleotides does not always guarantee homochirality in polypeptides and polynucleotides. Integrated scenarios containing the pathways from monomer to polymer should be proposed because in the pathways oligomers and polymers as well as monomers racemize (or epimerize), degrade, and condense. This research addresses epimerization and degradation of dipeptides under γ-rays irradiation by a cobalt-60 (Co) radiation source. The different rate constants of epimerization between diastereomeric dipeptides in the research suggest that the potential pathway toward homochirality could be much more complex.
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http://dx.doi.org/10.1007/s11084-016-9507-0 | DOI Listing |
J Neurosurg Case Lessons
January 2025
Department of Neurological Surgery, Pauline Braathen Neurological Center, Cleveland Clinic Florida, Weston, Florida.
Background: Radiation-induced sarcoma (RIS) is an exceptionally rare occurrence following radiation therapy, and manifestation usually occurs after a several-year latency period. Herein, the authors report the development of a radiation-induced osteosarcoma of the frontoparietal calvaria following treatment for an oligodendroglioma in an 84-year-old woman.
Observations: The patient had been diagnosed with a grade III anaplastic oligodendroglioma when she was 78 years old.
Carbon fibre reinforced polyetheretherketone (CFR-PEEK) implants have gained interest because of reported biomechanical advantages and radio-lucent properties. The aim of this study was to evaluate the role of CFR-PEEK nails in patients with metastatic bone disease (MBD). We performed a retrospective cohort study evaluating patients with MBD undergoing intramedullary (IM) nailing for prophylaxis or fixation of pathological fractures using CFR- PEEK or titanium implants.
View Article and Find Full Text PDFActa Orthop Belg
December 2024
COVID-19 has extensively affected the health-care organization with varying impact on different medical specialties. Long term ICU admission is associated with a less familiar complication: the formation of heterotopic ossifications (HO). In this case report we would like to emphasize the unrecognized burden of the coronavirus pandemic in patient care from the perspective of the orthopedic surgeon.
View Article and Find Full Text PDFJ Am Podiatr Med Assoc
January 2025
‡Department of Plastic Surgery, Medstar Georgetown University Hospital, Washington, DC.
Background: The formation of heterotopic ossification (HO) is a common complication after transosseous partial foot amputation. Development of HO in weightbearing and/or superficial areas can lead to increased pressures, which increases the likelihood of wound formation and pain. Current treatment modalities for HO of the foot include mechanical off-loading and surgical resection; however, prophylactic measures such as nonsteroidal anti-inflammatory drugs, bisphosphonates, and other medical therapies have been attempted previously with mixed efficacy.
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