158 research outputs found
Comparison of three-dimensional printed patient-specific guides versus freehand approach for radial osteotomies in normal dogs: Ex vivo model.
OBJECTIVE
To compare the accuracy of three-dimensional (3D) printed patient-specific guide (PSG) with a freehand (FH) approach for radial osteotomies in ex vivo normal dogs.
STUDY DESIGN
Experimental study.
ANIMALS
Twenty four ex vivo thoracic limb pairs from normal beagle dogs.
METHODS
Computed tomography (CT) images were collected preoperatively and postoperatively. Three osteotomies tested (n = 8/group) were: (1) uniplanar 30° frontal plane wedge ostectomy, (2) oblique plane (30° frontal, 15° sagittal) wedge ostectomy, and (3) single oblique plane osteotomy (SOO, 30° frontal, 15° sagittal, and 30° external). Limb pairs were randomized to a 3D PSG or FH approach. The resultant osteotomies were compared with virtual target osteotomies by surface shape-matching postoperative to the preoperative radii.
RESULTS
The mean ± standard deviation osteotomy angle deviation for all 3D PSG osteotomies (2.8 ± 2.8°, range 0.11-14.1°) was less than for the FH osteotomies (6.4 ± 6.0°, range 0.03-29.7°). No differences were found for osteotomy location in any group. In total, 84% of 3D PSG osteotomies were within 5° deviance from the target compared to 50% of freehand osteotomies.
CONCLUSION
Three-dimensional PSG improved FH accuracy of osteotomy angle in select planes and the most complex osteotomy orientation in a normal ex vivo radial model.
CLINICAL SIGNIFICANCE
Three-dimensional PSGs provided more consistent accuracy, which was most notable in complex radial osteotomies. Future work is needed to investigate guided osteotomies in dogs with antebrachial bone deformities
Giant cell formation produced by laser microbeam irradiation of chromatin in Chinese hamster cells
A pulsed laser microbeam of wavelength 532 nm was used to produce visible small lesions in the nucleoplasm or in the cytoplasm of V79 Chinese hamster cells. Transmission electron microscopy (TEM) of microirradiated nuclei showed that the lesions were produced within the nucleus and comprised between 0.2 and 0.5% of the total chromatin. Serial sections above and below the lesion site did not reveal any detectable chromatin damage, indicating that a visible lesion was restricted to the focal point of the beam. Whereas cells microirradiated anywhere in the cytoplasm showed normal clonal growth with few exceptions, the cells containing nuclear lesions did not enter mitosis at the time of unirradiated controls. Instead they formed giant cells in a high percentage of cases (72/99). The DNA content of these cells was considerably increased suggesting polyploidization. In some cases, division of giant cells was observed resulting in non-viable daughter cells containing micronuclei. Further evidence that the induction of giant cell formation depends on chromatin damage was obtained by microirradiation of chromosomes in anaphase. Here, giant cell formation was observed in the daughter cell which received microirradiated chromatin, whereas microirradiation of cytoplasm between the moving sets of chromosomes did not affect subsequent divisions of both daughter cells. Our data point out that loss of reproductive integrity and giant cell formation can be induced by damage at many sites of the chromosome complement
Accuracy of pin placement in the canine thoracolumbar spine using a free-hand probing technique versus 3D-printed patient-specific drill guides: An ex-vivo study.
OBJECTIVE
To compare pin placement accuracy, intraoperative technique deviations, and duration of pin placement for pins placed by free-hand probing (FHP) or 3D-printed drill guide (3DPG) technique.
SAMPLE POPULATION
Four greyhound cadavers.
METHODS
Computed tomography (CT) examinations from T6-sacrum were obtained for determination of optimal pin placement and 3DPG creation. Two 3.2/2.4-mm positive profile pins were inserted per vertebra, one left and one right from T7-L7 (FHP [n = 56]; 3DPG [n = 56]) by one surgeon and removed for repeat CT. Duration of pin placement and intraoperative deviations (unanticipated deviations from planned technique) were recorded. Pin tracts were graded by two blinded observers using modified Zdichavsky classification. Descriptive statistics were used.
RESULTS
A total of 54/56 pins placed with 3DPGs were assigned grade I (optimal placement) compared with 49/56 pins using the FHP technique. A total of 2/56 pins placed with 3DPGs and 3/56 pins using the FHP technique were assigned grade IIa (partial medial violation). A total of 4/56 pins placed using the FHP technique were assigned grade IIIa (partial lateral violation). No pins were assigned grade IIb (full medial violation). Intraoperative technique deviations occurred with 6/56 pins placed using the FHP technique and no pins with 3DPGs. Overall, pins were placed faster (mean ± SD 2.6 [1.3] vs. 4.5 [1.8] min) with 3DPGs.
CONCLUSIONS
Both techniques were accurate for placement of spinal fixation pins. The 3DPG technique may decrease intraoperative deviations and duration of pin placement.
CLINICAL RELEVANCE
Both techniques allow accurate pin placement in the canine thoracolumbar spine. The FHP technique requires specific training and has learning curve, whereas 3DPG technique requires specific software and 3D printers
Patients With Generalized Joint Hypermobility Have Thinner Superior Hip Capsules and Greater Hip Internal Rotation on Physical Examination
PURPOSE: To compare preoperative hip range of motion (ROM), hip capsular thickness on magnetic resonance imaging (MRI), and bony morphology on radiographs and computed tomography (CT) between patients with and without joint hypermobility as measured by the Beighton Test score (BTS), with subanalysis based on sex and age.
METHODS: Consecutive patients who underwent hip arthroscopy for a diagnosis of femoroacetabular impingement syndrome with or without dysplasia were retrospectively reviewed. Patient BTS, hip ROM, demographics, surgical data, morphologic measures on radiographs and CT, and MRI findings including hip capsule thickness at various locations were compiled. Multiple statistical tests were performed, including multivariable linear or logistic regression models, while controlling for BTS, age, and sex.
RESULTS: In total, 99 patients were included with a mean age of 29 ± 9.9 years; 62 (62.6%), were female. Forty patients (40.4%) had a BTS ≥4. Female patients (P \u3c .001) and younger patients (26.7 vs 30.9 years, P = .030) were more likely to have a BTS ≥4. Male patients had significantly thicker superior capsules (3.4 mm vs. 2.8 mm, P = .034). BTS was not associated with capsular thickness when controlling for sex. On CT, femoral version (18.9° vs 11.4°, P \u3c .001), and McKibben index (37.8° vs. 28.2°, P \u3c .001) were significantly greater in those with a BTS ≥4. Patients with a BTS ≥4 had more hip internal rotation at 90° of flexion (15.0° vs 10.0°, P \u3c .001), when prone (30.0° vs 20.0°, P = .004), and in extension (10.0° vs. 5.0°, P \u3c .001).
CONCLUSIONS: All female patients, regardless of Beighton score, and all patients with a BTS ≥4 indicated for primary hip arthroscopy for femoroacetabular impingement syndrome with or without dysplasia were more likely to have thinner superior hip capsules on MRI and greater hip internal rotation on exam. Bony morphologic differences exist between sexes and between patients with and without hypermobility, likely contributing to differences in ROM.
LEVEL OF EVIDENCE: III, retrospective cohort study
Health Insurance Reform Saving Millions
<p>Supplemental material, JOP780713_Supplementary_Figures for High dose psilocybin is associated with positive subjective effects in healthy volunteers by Christopher R Nicholas, Kelsey M Henriquez, Michele C Gassman, Karen M Cooper, Daniel Muller, Scott Hetzel, Randall T Brown, Nicholas V Cozzi, Chantelle Thomas and Paul R Hutson in Journal of Psychopharmacology</p
Epigenetics in Society
Would you take a potentially life-saving drug if you knew that your children and grandchildren might suffer the side effects?
Would you change your lifestyle if it meant you could reverse disadvantages built into your genes?
Would you be comfortable if corporations could infer intimate details about your life history without asking?
What if that data could improve your quality of life?
Epigenetics - our epigenome - controls how our genes behave without altering their sequence. Just about everything affects it, from nutrition, drugs, and toxins to child rearing, culture, and society. Many diseases, from obesity to addiction to cancer, can be linked to epigenetic modifications. Furthermore, throughout development and life, from conception to death, the exposures you have will not only affect your own epigenome, but potentially also your child’s, and your grandchild’s. This rapidly expanding field of biological, physiological, sociological, and psychological research could be key to discovering why, and more importantly how, we are the way we are.
Epigenetics has consequences for medicine, pregnancy, childcare, law and how we live on an everyday basis. This book will provide a comprehensive introduction to the mechanisms and real-life consequences of epigenetics, and will arm the reader with the knowledge necessary to make informed decisions about the future of epigenetics in modern society. This is a call for serious consideration about the effects of epigenetics on society.
Epigenetics has been independently peer-reviewed for accuracy by international experts. It is written by students of diverse disciplines, and intended for students and educated lay people.https://scholar.uwindsor.ca/emergingscholarspress/1000/thumbnail.jp
Use of particle tracking to determine optimal release dates and locations for rehabilitated neonate sea turtles
Sea turtles found stranded on beaches are often rehabilitated before being released back into the wild. The location and date of release is largely selected on an informal basis, which may not maximize the chance of survival. As oceanic conditions have a large influence on the movements of neonate sea turtles, this study aimed to identify the best locations and months to release rehabilitated sea turtles that would assist in their transport by ocean currents to the habitat and thermal conditions required for their survival. A particle tracking model, forced by ocean surface velocity fields, was used to simulate the dispersal pathways of millions of passively drifting particles released from different locations in Western Australia. The particles represented rehabilitated, neonate turtles requiring oceanic habitats [green (Chelonia mydas), hawksbill (Eretmochelys imbricata) and loggerheads (Caretta caretta)] and flatback turtles (Natator depressus) which require neritic habitats. The results clearly identified regions and months where ocean currents were more favorable for transport to suitable habitats. Tantabiddi, near Exmouth on the north-west coast, was consistently the best location for release for the oceanic species, with dominant offshore-directed currents and a very narrow continental shelf reducing the time taken for particles to be transported into deep water. In contrast, release locations with more enclosed geography, wide continental shelves, and/or proximity to cooler ocean temperatures were less successful. Our results produced a decision support system for the release of neonate marine turtles in Western Australia and our particle tracking approach has global transferability
Epic Aspects of Retail Encounters: The Iliad of Hollister
Much has been written about myth and the marketplace. Consumer research has added immeasurably to academics’ appreciation of the myths that inhere in fabulous flagship stores and experiential retailing more generally. Studies of consumer mythopoeia, however, have tended to muffle the martial side of retailing, the heroic struggles that some customers undergo in-store. This article argues that the epic offers valuable insights into martial matters, and more. Although epic and myth overlap, they are far from identical. The former is characterized by conventions that can help illuminate consumers’ quests, not least their disturbing journeys through the underworld. These are considered in relation to Hollister (HCo), a phenomenally successful retail chain that’s renowned for its antithetical atmospherics and inky interior design. A qualitative study of Hollister lovers and haters casts light on the epic in action and adds to scholars’ understanding of immersive retailing experiences
Challenges in Diagnosing Paediatric Malaria in Dar es Salaam, Tanzania.
Malaria is a major cause of paediatric morbidity and mortality. As no clinical features clearly differentiate malaria from other febrile illnesses, and malaria diagnosis is challenged by often lacking laboratory equipment and expertise, overdiagnosis and overtreatment is common. Children admitted with fever at the general paediatric wards at Muhimbili National Hospital (MNH), Dar es Salaam, Tanzania from January to June 2009 were recruited consecutively and prospectively. Demographic and clinical features were registered. Routine thick blood smear microscopy at MNH was compared to results of subsequent thin blood smear microscopy, and rapid diagnostics tests (RDTs). Genus-specific PCR of Plasmodium mitochondrial DNA was performed on DNA extracted from whole blood and species-specific PCR was done on positive samples. Among 304 included children, 62.6% had received anti-malarials during the last four weeks prior to admission and 65.1% during the hospital stay. Routine thick blood smears, research blood smears, PCR and RDT detected malaria in 13.2%, 6.6%, 25.0% and 13.5%, respectively. Positive routine microscopy was confirmed in only 43% (17/40), 45% (18/40) and 53% (21/40), by research microscopy, RDTs and PCR, respectively. Eighteen percent (56/304) had positive PCR but negative research microscopy. Reported low parasitaemia on routine microscopy was associated with negative research blood slide and PCR. RDT-positive cases were associated with signs of severe malaria. Palmar pallor, low haemoglobin and low platelet count were significantly associated with positive PCR, research microscopy and RDT. The true morbidity attributable to malaria in the study population remains uncertain due to the discrepancies in results among the diagnostic methods. The current routine microscopy appears to result in overdiagnosis of malaria and, consequently, overuse of anti-malarials. Conversely, children with a false positive malaria diagnosis may die because they do not receive treatment for the true cause of their illness. RDTs appear to have the potential to improve routine diagnostics, but the clinical implication of the many RDT-negative, PCR-positive samples needs to be elucidated.\u
Quantifying the competing influences of lithology and throw rate on bedrock river incision.
No embargo required
- …