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United European Gastroenterology Journal Jun 2017The primary objective of this study was to assess proximal disease extension of ulcerative colitis (UC) over time, with disease behaviour pattern and risk factors for...
OBJECTIVE
The primary objective of this study was to assess proximal disease extension of ulcerative colitis (UC) over time, with disease behaviour pattern and risk factors for proximal disease extension and colectomy as secondary aims.
METHODS
All cumulative incident cases diagnosed with UC at the Academic Medical Center between January 1990 and December 2009 were studied. The cumulative risk of colectomy was calculated by Kaplan-Meier analysis. The Cox proportional hazards regression was used to identify risk factors associated with proximal disease extension and colectomy.
RESULTS
In total, 506 UC patients were included with a median age of 33 years (IQR 23-41) at diagnosis. Ninety-five (18.8%) patients underwent colectomy during follow-up. Median follow-up was 10 years (IQR 5-15). Initial disease extent was evaluable in 416 patients, of whom 142 (34.1%) had proctitis, 155 (37.3%) left-sided colitis and 119 (28.6%) pancolitis. Proximal disease extension was observed in 120 (28.8%) patients during follow-up (51 proctitis to left-sided colitis, 39 proctitis to extensive colitis and 30 left-sided to extensive colitis). Disease behaviour was evaluable in 378 patients, of whom 244 (64.6%) had less than one relapse per year. Younger age at diagnosis (HR 0.98, 95% CI 0.96-0.99) and continuous active disease (HR 2.18, 95% CI 1.27-3.73) were independent risk factors for proximal disease extension. The cumulative risk of colectomy did not change over time between patients diagnosed before and after the year 2000 ( = 0.341). Continuous active disease (HR 7.05, 95% CI 4.23-11.77), systemic steroids (HR 3.25, 95% CI 1.37-7.71) and cyclosporine treatment (HR 2.80, 95% CI 1.66-4.72) were independent risk factors for colectomy, whereas proctitis at diagnosis (HR 0.43, 95% CI 0.22-0.86) carried a lower risk.
CONCLUSION
In one-third of UC patients, left-sided disease at diagnosis will extend proximally during 10 years of follow-up. Proximal disease extension was not a risk factor for colectomy, but the risk of colectomy is rather determined by continuous disease activity, and use of systemic steroids and cyclosporine.
PubMed: 28588887
DOI: 10.1177/2050640616679552 -
BMC Ophthalmology Apr 2016To determine the stereoacuity threshold with a 3D laptop equipped with 3D shutter glasses, and to evaluate the effect of different shape and size of test symbols and...
BACKGROUND
To determine the stereoacuity threshold with a 3D laptop equipped with 3D shutter glasses, and to evaluate the effect of different shape and size of test symbols and different type of disparities to stereoacuity.
METHODS
Thirty subjects with a visual acuity in each eye of at least 0 logMAR and a stereoacuity of at least 32 arcsec (as assessed in Fly Stereo Acuity Test) were recruited. Three target symbols-tumbling "E", tumbling "C", and "□"-were displayed, each with six different sizes representing a visual acuity ranging from 0.5 to 0 logMAR when tested at 4.1 m, and with both crossed and uncrossed disparities. Two test systems were designed - fixed distance of 4.1 m and one for variable distance. The former has disparities ranging from 10 to 1000 arcsec. Each subject completed 36 trials to investigate the effect of different symbol sizes and shapes, and disparity types on stereoacuity. In the variable distance system, each subject was tested 12 times for the same purposes, both proximally and distally (the point where the 3D effect just appears and where it just disappears respectively), and the mean value was calculated from the mean proximal and distal distances.
RESULTS
No significant difference was found among the groups in the fixed distance test system (Kruskal-Wallis test; Chi-square = 29.844, P = 0.715). Similarly, no significant difference was found in the variable distance system (Kruskal-Wallis test; proximal: Chi-square = 5.687, P = 0.338; distal: Chi-square = 5.898, P = 0.316; mean: Chi-square = 6.152, P = 0.292).
CONCLUSIONS
Evaluating stereoacuity using this measurement system was convenient and effective. Changes in target shape and size and disparity types had no significant effect on stereoacuity. It would be helpful to choose optimal targets according to different purposes using computer-assisted 3D measurements.
Topics: Adult; Analysis of Variance; Depth Perception; Diagnosis, Computer-Assisted; Eyeglasses; Female; Humans; Imaging, Three-Dimensional; Male; Sensory Thresholds; Vision Tests; Vision, Binocular; Visual Acuity; Young Adult
PubMed: 27112418
DOI: 10.1186/s12886-016-0223-3 -
Biomolecules Jan 2021The function of retinoic acid (RA) during limb development is still debated, as loss and gain of function studies led to opposite conclusions. With regard to limb... (Review)
Review
The function of retinoic acid (RA) during limb development is still debated, as loss and gain of function studies led to opposite conclusions. With regard to limb initiation, genetic studies demonstrated that activation of FGF10 signaling is required for the emergence of limb buds from the trunk, with and RA signaling acting upstream in the forelimb field, whereas and act upstream in the hindlimb field. Early studies in chick embryos suggested that RA as well as and () are required for subsequent proximodistal patterning of both forelimbs and hindlimbs, with RA diffusing from the trunk, functioning to activate specifically in the proximal limb bud mesoderm. However, genetic loss of RA signaling does not result in loss of limb expression and limb patterning is normal, although expression is reduced in trunk somitic mesoderm. More recent studies demonstrated that global genetic loss of results in a somite defect and failure of limb bud initiation. Other new studies reported that conditional genetic loss of in the limb results in proximodistal patterning defects, and distal FGF8 signaling represses to constrain its expression to the proximal limb. In this review, we hypothesize that RA and both function in the trunk to initiate forelimb bud initiation, but that limb expression is activated proximally by a factor other than RA and repressed distally by FGF8 to generate proximodistal patterning.
Topics: Animals; Extremities; Fibroblast Growth Factors; Gene Expression Regulation, Developmental; Myeloid Ecotropic Viral Integration Site 1 Protein; Signal Transduction; Tretinoin
PubMed: 33435477
DOI: 10.3390/biom11010080 -
Journal of Wrist Surgery Dec 2021The authors present a new comprehensive arthroscopic anatomical description of the fibrocartilage complex "TFCC" which is related to the current TFCC functional and...
The authors present a new comprehensive arthroscopic anatomical description of the fibrocartilage complex "TFCC" which is related to the current TFCC functional and pathological knowledge. Our description of the TFCC is based on an arthroscopic view from the 3-4 portal as observed in more than 100 wrist arthroscopies in fresh cadavers and more than 1000 diagnostic and/or therapeutic wrist arthroscopies. TFCC is considered as a 3-D-3-part box-like structure (Reins, Wall and Disc). The first TFCC component ("R") corresponds to 2 strong radio-ulnar ligamentous Reins, one dorsal (DRUL) and one palmar (PRUL). This "V-shaped" RUL reins diverge from the fovea and ulnar styloid to the volar and dorsal edges of the sigmoid notch. It is a main stabilizer of the DRUJ. The second TFCC component ("W") is a continuous, radially concave Peripheral Capsular Wall attached and perpendicular to the RUL reins. It surrounds the ulnar aspect of the ulno-carpal interval while attaching to the RUL reins proximally and to the medial carpus distally. Along with the radiocarpal ligaments, the TFCC peripheral capsular wall contributes to the stability of the carpus with respect to the radius-ulna entity. This is especially true for the thick volar TFCC capsular wall. The third TFCC component ("D") is the disc proper which is a static and dynamic shock absorber intercalated between the ulnar head and the medial proximal row in the coronal/sagittal planes and between the two strands of the RUL in the axial plane. Its pathology is influenced and related to the ulnar variance. This new arthroscopic description of the TFCC provides a comprehensive anatomical, functional ant pathological background for TFCC disorders analysis and treatment. Currently known disorders are included as "R 1,2,3,4", "W 1, 2, 3, 4", and "D 1, 2". Combined TFCC disorders and further new pathology descriptions may be included in this open classification.
PubMed: 34881114
DOI: 10.1055/s-0041-1732416 -
Biochemistry Nov 2022Fusicoccadiene synthase from the fungus (PaFS) is an assembly-line terpene synthase that catalyzes the first two steps in the biosynthesis of Fusiccocin A, a diterpene...
Fusicoccadiene synthase from the fungus (PaFS) is an assembly-line terpene synthase that catalyzes the first two steps in the biosynthesis of Fusiccocin A, a diterpene glycoside. The C-terminal prenyltransferase domain of PaFS catalyzes the condensation of one molecule of C dimethylallyl diphosphate and three molecules of C isopentenyl diphosphate to form C geranylgeranyl diphosphate, which then transits to the cyclase domain for cyclization to form fusicoccadiene. Previous structural studies of PaFS using electron microscopy (EM) revealed a central octameric prenyltransferase core with eight cyclase domains tethered in random distal positions through flexible 70-residue linkers. However, proximal prenyltransferase-cyclase configurations could be captured by covalent cross-linking and observed by cryo-EM and mass spectrometry. Here, we use cryo-EM to show that proximally configured prenyltransferase-cyclase complexes are observable even in the absence of covalent cross-linking; moreover, such complexes can involve multiple cyclase domains. A conserved basic patch on the prenyltransferase domain comprises the primary touchpoint with the cyclase domain. These results support a model for transient prenyltransferase-cyclase association in which the cyclase domains of PaFS are in facile equilibrium between proximal associated and random distal positions relative to the central prenyltransferase octamer. The results of biophysical measurements using small-angle X-ray scattering, analytical ultracentrifugation, dynamic light scattering, and size-exclusion chromatography in-line with multi-angle light scattering are consistent with this model. This model accordingly provides a framework for understanding substrate transit between the prenyltransferase and cyclase domains as well as the cooperativity observed for geranylgeranyl diphosphate cyclization.
Topics: Dimethylallyltranstransferase; Alkyl and Aryl Transferases; Diterpenes
PubMed: 36227241
DOI: 10.1021/acs.biochem.2c00509 -
AJNR. American Journal of Neuroradiology Jun 2019Transverse sinus stenosis can lead to pseudotumor cerebri syndrome by elevating the cerebral venous pressure. The occipital emissary vein is an inconstant emissary vein...
BACKGROUND AND PURPOSE
Transverse sinus stenosis can lead to pseudotumor cerebri syndrome by elevating the cerebral venous pressure. The occipital emissary vein is an inconstant emissary vein that connects the torcular herophili with the suboccipital veins of the external vertebral plexus. This retrospective study compares the prevalence and size of the occipital emissary vein in patients with pseudotumor cerebri syndrome with those in healthy control subjects to determine whether the occipital emissary vein could represent a marker of pseudotumor cerebri syndrome.
MATERIALS AND METHODS
The cranial venous system of 46 adult patients with pseudotumor cerebri syndrome (group 1) was studied on CT venography images and compared with a group of 92 consecutive adult patients without pseudotumor cerebri syndrome who underwent venous assessment with gadolinium-enhanced 3D-T1 MPRAGE sequences (group 2). The presence of an occipital emissary vein was assessed, and its proximal (intraosseous) and distal (extracranial) maximum diameters were measured and compared between the 2 groups. Seventeen patients who underwent transverse sinus stent placement had their occipital emissary vein diameters measured before and after stent placement.
RESULTS
Thirty of 46 (65%) patients in group 1 versus 29/92 (31.5%) patients in group 2 had an occipital emissary vein ( < .001). The average proximal and distal occipital emissary vein maximum diameters were significantly larger in group 1 (2.3 versus 1.6 mm, <.005 and 3.3 versus 2.3 mm, < .001). The average maximum diameters of the occipital emissary vein for patients who underwent transverse sinus stent placement were larger before stent placement than after stent placement: 2.6 versus 1.8 mm proximally ( < .06) and 3.7 versus 2.6 mm distally ( < .005).
CONCLUSIONS
Occipital emissary veins are more frequent and larger in patients with pseudotumor cerebri syndrome than in healthy subjects, a finding consistent with their role as collateral venous pathway in transverse sinus stenosis. A prominent occipital emissary vein is an imaging sign that should raise the suspicion of pseudotumor cerebri syndrome.
Topics: Adult; Cerebral Veins; Cranial Sinuses; Female; Humans; Imaging, Three-Dimensional; Male; Pseudotumor Cerebri; Retrospective Studies
PubMed: 31072972
DOI: 10.3174/ajnr.A6061 -
Clinical Biomechanics (Bristol, Avon) Feb 2020Percutaneous osseointegrated devices for skeletal fixation of prosthetic limbs have the potential to improve clinical outcomes in the transhumeral amputee population....
BACKGROUND
Percutaneous osseointegrated devices for skeletal fixation of prosthetic limbs have the potential to improve clinical outcomes in the transhumeral amputee population. Initial endoprosthesis stability is paramount for long-term osseointegration and safe clinical introduction of this technology. We evaluated an endoprosthetic design featuring a distally porous coated titanium stem with proximal slots for placement of bicortical interlocking screws.
METHODS
Yield load, ultimate failure load, and construct stiffness were measured in 18 pairs of fresh-frozen and thawed cadaver humeri, at distal and proximal amputation levels, without and with screws, under axial pull-out, torsion, and bending loads. Paired statistical comparisons were performed without screws at the two resection levels, and at distal and proximal levels with and without screws.
FINDINGS
Without screws, the location of the amputation influenced the stability only in torsional yield (p = 0.032) and torsional ultimate failure (p = 0.033). Proximally, the torsional yield and the torsional ultimate failure were 44% and 47% of that distally. Screws improved stability. In axial pull-out, screws increased the distal ultimate failure 3.2 times (p = 0.003). In torsion, screws increased the yield at the proximal level 1.9 times (p = 0.035), distal ultimate failure load 3.3 times (p = 0.016) and proximal ultimate failure 6.4 times (p = 0.013). In bending, screws increased ultimate failure at the proximal level 1.6 times (p = 0.026).
INTERPRETATION
Proximal slots and bicortical interlocking screws may find application in percutaneous osseointegrated devices for patients with amputations, especially in the less stable proximal bone of a short residual limb.
Topics: Amputees; Biomechanical Phenomena; Bone Plates; Bone Screws; Female; Humans; Humerus; Male; Mechanical Phenomena; Osseointegration
PubMed: 31862604
DOI: 10.1016/j.clinbiomech.2019.12.005 -
BJU International Jan 2017To describe a new hypothesis for the initial events leading to urinary stones. A biomechanical perspective on Randall's plaque formation through form and function... (Review)
Review
OBJECTIVES
To describe a new hypothesis for the initial events leading to urinary stones. A biomechanical perspective on Randall's plaque formation through form and function relationships is applied to functional units within the kidney, we have termed the 'medullo-papillary complex' - a dynamic relationship between intratubular and interstitial mineral aggregates.
METHODS
A complete MEDLINE search was performed to examine the existing literature on the anatomical and physiological relationships in the renal medulla and papilla. Sectioned human renal medulla with papilla from radical nephrectomy specimens were imaged using a high resolution micro X-ray computed tomography. The location, distribution, and density of mineral aggregates within the medullo-papillary complex were identified.
RESULTS
Mineral aggregates were seen proximally in all specimens within the outer medulla of the medullary complex and were intratubular. Distal interstitial mineralisation at the papillary tip corresponding to Randall's plaque was not seen until a threshold of proximal mineralisation was observed. Mineral density measurements suggest varied chemical compositions between the proximal intratubular (330 mg/cm ) and distal interstitial (270 mg/cm ) deposits. A review of the literature revealed distinct anatomical compartments and gradients across the medullo-papillary complex that supports the empirical observations that proximal mineralisation triggers distal Randall's plaque formation.
CONCLUSION
The early stone event is initiated by intratubular mineralisation of the renal medullary tissue leading to the interstitial mineralisation that is observed as Randall's plaque. We base this novel hypothesis on a multiscale biomechanics perspective involving form and function relationships, and empirical observations. Additional studies are needed to validate this hypothesis.
Topics: Calcinosis; Humans; Kidney Diseases; Kidney Medulla; Minerals; Urinary Calculi
PubMed: 27306864
DOI: 10.1111/bju.13555 -
Arthroscopy Techniques Apr 2020The proximal biceps tendon is a common source of shoulder pain and dysfunction. When patients continue to have pain after exhaustive nonoperative treatment, the long...
The proximal biceps tendon is a common source of shoulder pain and dysfunction. When patients continue to have pain after exhaustive nonoperative treatment, the long head of the biceps tendon can be effectively treated with a tenotomy or tenodesis. Although biceps tenotomy is a less complex and highly reliable treatment, there is the potential for suboptimal outcomes including muscle cramping, fatigue, cosmetic deformity, and supination weakness. Biceps tenodesis eliminates the source of shoulder pain while securing the tendon proximally. Currently, there are multiple techniques for performing a biceps tenodesis (arthroscopic, open suprapectoral, open subpectoral) and myriad fixation methods (bio-tenodesis screw, bone bridge, cortical button, all-suture anchor). Our article presents a technique for a mini-open subpectoral biceps tenodesis using an onlay technique with an all-suture anchor preloaded with needles. This technique allows efficient and proper tendon fixation while minimizing potential complications.
PubMed: 32368463
DOI: 10.1016/j.eats.2019.11.017 -
Journal of Gastrointestinal Surgery :... Oct 2018Acquired aerodigestive fistulae (ADF) are rare, but associated with a high mortality rate. We present our experience of the diagnosis, management and outcomes of...
BACKGROUND
Acquired aerodigestive fistulae (ADF) are rare, but associated with a high mortality rate. We present our experience of the diagnosis, management and outcomes of patients with ADFs treated at a tertiary centre. Utilising our findings, we propose an anatomical classification system, demonstrating how specific features of an ADF may determine management.
METHODS
A clinical database was searched and 48 patients with an ADF were identified. A classification system was developed based on anatomical location of the ADF and differences in clinico-pathological features based on this categorisation were performed, with the chi-squared test used for inferential analyses and Kaplan-Meier curves with log-rank test to assess survival.
RESULTS
Twenty (41.6%) patients developed an ADF secondary to malignancy, with previous radiotherapy (18.7%), post-operative anastomotic dehiscence and endotherapy (14.6% each) representing other causes. Thirty-one patients were managed with tracheal and/or oesophageal stents and eight underwent surgical repair. The classification system demonstrated benign causes of ADF were either proximally or distally sited, whilst a malignant cause resulted in mid-tracheal fistulae (p = 0.001), with the latter associated with poorer survival. ADFs over 20 mm in size were associated with poor survival (p = 0.011), as was the use of previous radiotherapy. Proximal and distal ADFs were associated with improved survival (p = 0.006), as were those patients managed surgically (p = 0.001).
CONCLUSION
By classifying ADFs, we have demonstrated that anatomical location correlates with the size, history of malignancy, previous radiotherapy and aetiology of ADF, which can affect management. The proposed classification system will aid in formulating multi-modality individualised treatment plans.
Topics: Adult; Aged; Anastomosis, Surgical; Female; Humans; Male; Middle Aged; Neoplasms; Postoperative Complications; Radiotherapy; Retrospective Studies; Stents; Survival Rate; Tracheoesophageal Fistula; Young Adult
PubMed: 29943138
DOI: 10.1007/s11605-018-3811-0