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Pathophysiology : the Official Journal... Dec 2022Previous studies suggest that the endothelial glycocalyx adds to vascular resistance, inhibits thrombosis, and is critical for regulating homogeneous blood flow and...
PURPOSE
Previous studies suggest that the endothelial glycocalyx adds to vascular resistance, inhibits thrombosis, and is critical for regulating homogeneous blood flow and ensuring uniform red blood cell (RBC) distribution. However, these functions and consequences of the glycocalyx have not been examined in the retina. We hypothesize that the endothelial glycocalyx is a critical regulator of retinal hemodynamics and perfusion and decreases the propensity for retinal thrombus formation.
METHODS
Hyaluronidase and heparinase, which are endothelial glycocalyx-degrading enzymes, were infused into mice. Fluorescein isothiocyanate-dextran (2000 kDa) was injected to measure lumen diameter, while RBC velocity and distribution were measured using fluorescently labeled RBCs. The diameters and velocities were used to calculate retinal blood flow and shear rates. Mean circulation time was calculated by measuring the difference between arteriolar and venular mean transit times. Rose Bengal dye was infused, followed by illumination with a green light to induce thrombosis.
RESULTS
The acute infusion of hyaluronidase and heparinase led to significant increases in both arteriolar (7%) and venular (16%) diameters in the retina, with a tendency towards increased arteriolar velocity. In addition, the degradation caused a significant decrease in the venular shear rate (14%). The enzyme infusion resulted in substantial increases in total retinal blood flow (26%) and retinal microhematocrit but no changes in the mean circulation time through the retina. We also observed an enhanced propensity for retinal thrombus formation with the removal of the glycocalyx.
CONCLUSIONS
Our data suggest that acute degradation of the glycocalyx can cause significant changes in retinal hemodynamics, with increases in vessel diameter, blood flow, microhematocrit, pro-thrombotic conditions, and decreases in venular shear rate.
PubMed: 36548208
DOI: 10.3390/pathophysiology29040052 -
International Ophthalmology Feb 2022To compare pupillary responses in patients with Coronavirus disease-2019 (COVID-19) during active infection and at 3rd months post-infection.
AIM
To compare pupillary responses in patients with Coronavirus disease-2019 (COVID-19) during active infection and at 3rd months post-infection.
METHODS
This study included 58 COVID-19 cases (mean age 47.23 ± 1.1 years). The scotopic, mesopic and photopic diameters were noted. Pupil diameters were noted at the 0, 1st, 2nd, 4th, 6th, 8th, and 10th seconds in reflex pupil dilation after the termination of a light. The average dilation speed was calculated at the 1st, 2nd, 4th, 6th, 8th, and 10th seconds. Pupil responses measured during COVID-19 infection and 3 months later were compared.
RESULTS
The mean scotopic and mesopic pupil diameter value of during COVID-19 infection was found lower than the 3rd month post-infection. (p = 0.001, p = 0.023; respectively). No statistically significant difference was found in the mean photopic pupil diameter and the mean pupil diameter at 0 s between measurements (p > 0.05, p = 0.734; respectively). The mean pupil diameter was significantly lower during COVID-19 infection at the 1st, 2nd, 4th, 6th, 8th and 10th seconds (p < 0.01, for each). The average dilation speed measurements at every second measured were lower in during COVID-19 infection than the 3rd months later (p = 0.001; p < 0.01 for each).
CONCLUSIONS
Pupil responses were found significantly different in COVID-19 cases when compared with the measurements taken three months later.
Topics: COVID-19; Color Vision; Humans; Middle Aged; Pupil; SARS-CoV-2
PubMed: 34613562
DOI: 10.1007/s10792-021-02053-z -
PloS One 2022Diameter is currently the only screening and diagnostic criterion for asymptomatic aneurysms. Therefore, aortic and lower-extremity arterial diameter has diagnostic,...
OBJECTIVE
Diameter is currently the only screening and diagnostic criterion for asymptomatic aneurysms. Therefore, aortic and lower-extremity arterial diameter has diagnostic, therapeutic, and prognostic importance. We aimed to determine aortic and lower-extremity arterial reference diameters in a general population and compare them according to age, sex, and other characteristics.
METHODS
We evaluated consecutive 3,692 patients who underwent computed tomography as part of a general health checkup from 2015-2019 in a single tertiary center. Aortic and lower-extremity arterial diameters and the most important factor related to arterial diameters were evaluated.
RESULTS
The mean diameter of the abdominal aorta was 17.490 ± 2.110 mm, while that of the common iliac artery was 10.851 ± 1.689 mm. The mean diameter of the abdominal aorta was 18.377 ± 1.766 mm in men and 15.884 ± 1.694 mm in women. Significant intersex differences were observed for all mean diameters and lengths. Multilinear regression analysis showed that age, sex, and body surface area impacted mean diameters of all measured sites except aorta and common iliac artery length. Between male and female patients matched for body surface area, there were significant intersex differences for all measured sites, except for common iliac artery length.
CONCLUSIONS
The mean diameter of the abdominal aorta in this healthy cohort was 17.490 ± 2.110 mm overall, 18.377 ± 1.766 mm in men, and 15.884 ± 1.694 mm in women. Arterial diameter increased with male sex, older age, and increased body surface area, and aortic diameters were larger in men than in women with the same body surface area.
Topics: Aorta, Abdominal; Aortic Aneurysm, Abdominal; Body Surface Area; Cohort Studies; Female; Humans; Iliac Artery; Male; Tomography, X-Ray Computed
PubMed: 35511926
DOI: 10.1371/journal.pone.0268077 -
European Journal of Radiology Open 2020To determine the role of Contrast enhanced MRI (CEMRI) in the evaluation of Cavernous sinus thrombosis (CST).
PURPOSE
To determine the role of Contrast enhanced MRI (CEMRI) in the evaluation of Cavernous sinus thrombosis (CST).
METHOD
The study included 7 patients with an imaging diagnosis of cavernous sinus thrombosis. A retrospective analysis of Contrast enhanced MRI of 9 affected cavernous sinuses and a control group of 7 patients (14 cavernous sinuses) was conducted. Various qualitative and quantitative parameters were then compared.
RESULTS
In the patient group, the mean Cavernous sinus (CS) diameter, Cavernous Internal Carotid Artery (ICA) diameter and Superior Ophthalmic Vein (SOV) diameter were 9.14 ± 0.56 mm, 3.5 mm ± 0.9 mm and 3.8 mm ± 1.79 mm respectively. While in the control group, the mean CS diameter, ICA diameter and SOV dimeter were 6.58 ± 0.54 mm, 4.6 mm ± 0.44 mm and 1.1 mm ± 0.11 mm respectively. The differences in the CS size, ICA and SOV diameters was statistically significant. (p < 0.05). Cut off points of ≥ 10 mm for CS diameter, ≥ 2.9 mm for SOV dilation, and ≤ 4.2 mm for ICA flow void diameter were estimated using receiver operating characteristic curves. Various other qualitative parameters, like bulging lateral walls of the sinus, heterogenous signal intensity with filling defects on post contrast images, abnormal dural enhancement along the lateral wall of the sinus and orbital apex involvement were more frequently observed in the CST group, in comparison to the control group.
CONCLUSIONS
CEMRI plays an invaluable role not only in the diagnosis of cavernous sinus thrombosis, but also in evaluating the extent of disease and its associated complications. The quantitative and qualitative parameters described here, provide more objectivity and accuracy in diagnosis of CST, thus, aiding prompt diagnosis and early treatment.
PubMed: 32154332
DOI: 10.1016/j.ejro.2020.100226 -
Plant, Cell & Environment Jun 2017Variation in xylem vessel diameter is one of the most important parameters when evaluating plant water relations. This review provides a synthesis of the... (Review)
Review
Variation in xylem vessel diameter is one of the most important parameters when evaluating plant water relations. This review provides a synthesis of the ecophysiological implications of variation in lumen diameter together with a summary of our current understanding of vessel development and its endogenous regulation. We analyzed inter-specific variation of the mean hydraulic vessel diameter (D ) across biomes, intra-specific variation of D under natural and controlled conditions, and intra-plant variation. We found that the D measured in young branches tends to stay below 30 µm in regions experiencing winter frost, whereas it is highly variable in the tropical rainforest. Within a plant, the widest vessels are often found in the trunk and in large roots; smaller diameters have been reported for leaves and small lateral roots. D varies in response to environmental factors and is not only a function of plant size. Despite the wealth of data on vessel diameter variation, the regulation of diameter is poorly understood. Polar auxin transport through the vascular cambium is a key regulator linking foliar and xylem development. Limited evidence suggests that auxin transport is also a determinant of vessel diameter. The role of auxin in cell expansion and in establishing longitudinal continuity during secondary growth deserve further study.
Topics: Indoleacetic Acids; Magnoliopsida; Plant Development; Species Specificity; Xylem
PubMed: 27304704
DOI: 10.1111/pce.12777 -
Journal of Personalized Medicine May 2022To investigate the association between Aorta (Ao), pulmonary artery (PA) diameters and the PA/Ao ratio with right (RV) and left ventricle (LV) volumetric properties in...
To investigate the association between Aorta (Ao), pulmonary artery (PA) diameters and the PA/Ao ratio with right (RV) and left ventricle (LV) volumetric properties in subjects free of cardiovascular diseases. In the KORA-MRI study, 339 subjects (mean age 56.3 ± 9.1 years; 43.7% female) underwent whole-body 3T-MRI. Ao and PA were measured on DIXON sequences. Cvi42 quantified cardiac functional parameters from a SSFP sequence. The relationship between ascending (AAo), and descending aorta (DAo), as well as PA diameters, and RV and LV function were assessed using linear regression models adjusted for age, sex, and cardiovascular risk factors. AAo and DAo diameter were associated with LV end-diastolic volume (β = 4.52, = 0.015; ß = 7.1, ≤ 0.001), LV end-systolic volume (β = 2.37, = 0.031; ß = 3.66, = 0.002), while DAo associated with RV end-diastolic volume (β = 6.45, = 0.006) and RV end-systolic volume (β = 3.9, = 0.011). PA diameter was associated with LV end-diastolic volume (β = 4.81, = 0.003). Interestingly, the PA/Ao ratio was only associated with RV end-diastolic and end-systolic volume (β = 4.48, = 0.029; ß = 2.82, = 0.037). Furthermore, we found different relationships between men and women. Ao and PA diameter were associated with LV and RV volumetric parameters in subjects free of cardiovascular diseases suggesting that ventricular volumetric performance directly relates to vascular diameter properties.
PubMed: 35743674
DOI: 10.3390/jpm12060889 -
Interactive Cardiovascular and Thoracic... Mar 2022Normal pulmonary artery (PA) diameter remains blurred and the definitions of PA aneurysm are heterogenous. We aimed to assess PA diameters, identify a threshold for...
OBJECTIVES
Normal pulmonary artery (PA) diameter remains blurred and the definitions of PA aneurysm are heterogenous. We aimed to assess PA diameters, identify a threshold for normal diameters, define PA aneurysms, possible predictors of PA size and evaluate the correlation with mid-ascending aortic diameters.
METHODS
Between April 2018 and August 2019, 497 consecutive patients who underwent whole-body computed tomographic angiography were reviewed. Clinical and imaging data were collected from our institutional database. Precise three-dimensional centreline measurements were taken. Linear regression analysis was performed to detect parameters associated with PA diameter. A two-stage model was created to identify potential predictors and the resulting statistically significant interactions were tested. Data were grouped and PA, standard deviation, and upper normal limits were calculated.
RESULTS
Among 497 patients with an average age of 51.4 (20.2) (74.6% males), the mean PA diameter measured 32.0 (4.6) mm [female: 31.2 (4.7) mm vs male: 32.2 (4.5) mm; P = 0.032]. The mean PA length, left PA and right PA diameters were similar between male and female patients. We found a significant correlation (r = 0.352; P < 0.001) between the PAs and mid-ascending aortic diameters. Body surface area (P = 0.032, β = 4.52 [0.40; 8.64] 95% CI) was the only significant influencing variable for PA diameter.
CONCLUSIONS
The normal mean PA diameter in a reference cohort is 32.0 (4.6) mm. Body surface area is the only influencing variable of PA diameter. The normal diameters measured and corresponding upper limits of normal revealed that a PA aneurysm should not be considered below a threshold of 45 mm.
Topics: Angiography; Computed Tomography Angiography; Female; Humans; Lung; Male; Middle Aged; Pulmonary Artery; Tomography, X-Ray Computed
PubMed: 34791257
DOI: 10.1093/icvts/ivab308 -
Journal of Clinical Medicine May 2022We aimed to determine whether retinal vessel diameters and retinal oxygen saturation in newly diagnosed patients with multiple sclerosis (pwMS) are different from those...
We aimed to determine whether retinal vessel diameters and retinal oxygen saturation in newly diagnosed patients with multiple sclerosis (pwMS) are different from those of a healthy population. Retinal blood vessel diameters were measured using imaging with a spectrophotometric non-invasive retinal oximeter. Twenty-three newly diagnosed untreated relapsing-remitting MS (RRMS) patients (mean age: 32.2 ± 7.5 years, age range = 18-50 years, 56.5% female) were measured and compared to 23 age- and sex-matched healthy controls (HCs) (mean age: 34.8 ± 8.1 years). Patients with Optic Neuritis were excluded. Retinal venular diameter (143.8 µm versus 157.8 µm: mean; = 0.0013) and retinal arteriolar diameter (112.6 µm versus 120.6 µm: mean; = 0.0089) were smaller in pwMS when compared with HCs, respectively. There was no significant difference in the oxygen saturation in retinal venules and arterioles in pwMS (mean: 60.0% and 93.7%; = 0.5980) compared to HCs (mean: 59.3% and 91.5%; = 0.8934), respectively. There was a significant difference in the median low contrast visual acuity (2.5% contrast) between the pwMS and the HC groups ( = 0.0143) Retinal arteriolar and venular diameter may have potential as objective biomarkers for MS.
PubMed: 35683496
DOI: 10.3390/jcm11113109 -
SAGE Open Medicine 2022Activities that require increased load bearing are known to cause bony hypertrophy. This phenomenon has been documented in the dominant arm of athletes in sports...
OBJECTIVE
Activities that require increased load bearing are known to cause bony hypertrophy. This phenomenon has been documented in the dominant arm of athletes in sports requiring significant utilization of a single limb. The literature addressing this effect in rodeo athletes, however, is minimal. Studies evaluating rodeo athletes are primarily focused on acute injury management rather than chronic symptoms resulting from changes in bone and soft tissue. We designed a study to evaluate bony hypertrophy in athletes without acute injury.
METHOD
Rodeo bareback riders presented with frequent pain in their grip arm, no radiographic evidence of injury, and clinical signs of peripheral nerve compression. Anteroposterior and lateral X-rays taken for initial evaluation in 17 bareback rodeo athletes were retrospectively reviewed. The diameter of bilateral ulnas was measured at its longitudinal midpoint. Ratio of Ulnar Diameters (grip arm/free arm) and Percentage Diameter Difference were calculated. An independent samples -test was used to assess differences in diameters of grip and non-grip arms.
RESULT
The mean ulnar diameter was 18.4 ± 3.5 in the grip arm and 16.6 ± 3.5 in the non-grip arm ( < 0.001). The mean ratio of grip to free arm ulnar diameter was 1.42 ± 0.21 (range = 1.05-1.92). The mean diameter percent difference measured 42.3% (range = 4.7%-92.0%), and the grip arm was observed to have a greater ulnar diameter compared to the non-grip arm.
CONCLUSION
There are significant anatomic differences in the grip arm of bareback rodeo athletes compared to the contralateral arm. In cases of persistent pain in the grip arm and no evidence of acute injury, these differences may be relevant to pain symptoms and should be considered as part of the assessment and treatment algorithm.
PubMed: 35223028
DOI: 10.1177/20503121221077831 -
Investigative Ophthalmology & Visual... May 2022Infantile nystagmus syndrome (INS) causes altered visual development and can be associated with abnormal retinal structure, to which vascular development of the retina...
PURPOSE
Infantile nystagmus syndrome (INS) causes altered visual development and can be associated with abnormal retinal structure, to which vascular development of the retina is closely related. Abnormal retinal vasculature has previously been noted in albinism but not idiopathic infantile nystagmus. We compared the number and diameter of retinal vessels in participants with albinism (PWA) and idiopathic infantile nystagmus (PWIIN) with controls.
METHODS
Fundus photography data from 24 PWA, 10 PWIIN, and 34 controls was analyzed using Automated Retinal Image Analyzer (ARIA) software on a field of analysis centered on the optic disc, the annulus of which extended between 4.2 mm and 8.4 mm in diameter.
RESULTS
Compared with controls, the mean number of arterial branches was reduced by 24% in PWA (15.5 vs. 20.3, P < 0.001), and venous branches were reduced in both PWA (29%; 12.9 vs. 18.2, P < 0.001) and PWIIN (17%; 15.1 vs. 18.2, P = 0.024). PWA demonstrated 7% thinner "primary" (before branching) arteries (mean diameter: 75.39 µm vs. 80.88 µm, P = 0.043), and 13% thicker (after branching) "secondary" veins (66.72 µm vs. 59.01 µm in controls, P = 0.009).
CONCLUSIONS
PWA and PWIIN demonstrated reduced retinal vessel counts and arterial diameters compared with controls. These changes in the superficial retinal vascular network may be secondary to underdevelopment of the neuronal network, which guides vascular development and is also known to be disrupted in INS.
Topics: Albinism; Genetic Diseases, X-Linked; Humans; Nystagmus, Congenital; Nystagmus, Pathologic; Optic Disk; Retinal Vessels
PubMed: 35616929
DOI: 10.1167/iovs.63.5.33