1,436 research outputs found
Retinal arterioles narrow with increasing duration of anti-retroviral therapy in HIV infection: a novel estimator of vascular risk in HIV?
No full textOBJECTIVES: HIV infection is associated with an increased risk of age-related morbidity mediated by immune dysfunction, atherosclerosis and inflammation. Changes in retinal vessel calibre may reflect cumulative structural damage arising from these mechanisms. The relationship of retinal vessel calibre with clinical and demographic characteristics was investigated in a population of HIV-infected individuals in South Africa. METHODS: Case-control study of 491 adults ≥30 years, composed of 242 HIV-infected adults and 249 age- and gender-matched HIV-negative controls. Retinal vessel calibre was measured using computer-assisted techniques to determine mean arteriolar and venular diameters of each eye. RESULTS: The median age was 40 years (IQR: 35-48 years). Among HIV-infected adults, 87.1% were receiving highly active antiretroviral therapy (HAART) (median duration, 58 months), their median CD4 count was 468 cells/µL, and 84.3% had undetectable plasma viral load. Unadjusted mean retinal arteriolar diameters were 163.67±17.69 µm in cases and 161.34±17.38 µm in controls (p = 0.15). Unadjusted mean venular diameters were 267.77±18.21 µm in cases and 270.81±18.98 µm in controls (p = 0.07). Age modified the effect of retinal arteriolar and venular diameters in relation to HIV status, with a tendency towards narrower retinal diameters in HIV cases but not in controls. Among cases, retinal arteriolar diameters narrowed with increasing duration of HAART, independently of age (167.83 µm 6 years, p-trend = 0.02), and with a HIV viral load >10,000 copies/mL while on HAART (p = 0.05). HIV-related venular changes were not detected. CONCLUSIONS: Narrowing of retinal arteriolar diameters is associated with HAART duration and viral load, and may reflect heightened inflammatory and pro-atherogenic states of the systemic vasculature. Measurement of retinal vascular calibre could be an innovative non-invasive method of estimating vascular risk in HIV-infected individuals
Plasminogen activator inhibitor-1 (PAI-1) activity and retinal vascular calibre in type 2 diabetes
No full textObjective: To describe relationships of retinal vascular calibre with plasminogen activator inhibitor-1 (PAI-1) and other cardiovascular risk factors in people with type 2 diabetes. Methods: Werecruited 112 community-based persons aged 44-83 years with type 2 diabetes, photo-documented retinal status using a digital fundus camera, and measured traditional and novel vascular risk factors. Retinal arteriolar and venular calibre and the arterio-venous ratio (AVR) were determined from fundus photographs using a validated computer-assisted method. Results: In adjusted linear regression models, PAI-1 activity was strongly associated with all measures of retinal vascular calibre: positively with arterioles ( p = 0.005) and AVR ( p = 0.001), and inversely with venules ( p = 0.001). In addition, wider arterioles were independently associated with waist-hip ratio ( p < 0.0001), HDL-C ( p = 0.015), and lower systolic blood pressure ( p = 0.042), whereas narrower venules were associated with older age and a higher albumin excretion rate. Neither arteriolar nor venular calibre was associated with plasma total homocysteine or C-reactive protein concentration. Conclusion: Retinal vascular calibre is independently associated with PAI-1 activity in type 2 diabetes. This finding supports a role for PAI-1 activity in the microvasculature of persons with type 2 diabetes and may explain the link between retinal vascular calibre and cardiovascular disease. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.L. Brazionis, J. Yau, K. Rowley, C. Itsiopoulos, K. O’Dea, T.Y. Wong and A. Jenkinshttp://www.elsevier.com/wps/find/journaldescription.cws_home/505949/description#descriptio
Increased retinal venular calibre in acute infections
No full textPopulation-based studies have demonstrated that increased retinal venular calibre is a risk factor for cardiac disease, cardiac events and stroke. Venular dilatation also occurs with diabetes, obesity, dyslipidemia and autoimmune disease where it is attributed to inflammation. This study examined whether the inflammation associated with infections also affected microvascular calibre. Participants with infections and CRP levels > 100 mg/L were recruited from the medical wards of a teaching hospital and assisted to complete a demographic and vascular risk factor questionnaire, and
to undergo non-mydriatic retinal photography (Canon CR5-45NM, Japan). They were then treated with appropriate antibiotics, and underwent repeat retinal imaging when their CRP levels had fallen to less than 100 mg/L. Retinal images were examined for arteriole and venular calibre using validated semi-automated software based on Knudtson’s modification of the Parr-Hubbard formula (IVAN, U Wisconsin). Differences in inflammatory markers and calibre were examined using the paired t-test for continuous variables. Determinants of calibre were calculated from multiple linear regression analysis.
Forty-one participants with respiratory (27, 66%), urinary (6, 15%), skin (5, 12%), or miscellaneous (3, 7%) infections were studied. After antibiotic treatment, participants’ mean CRP levels fell from 172.9 ± 68.4 mg/L to 42.2 ± 28.2 mg/L (p 100 mg/L that
persisted at review (199.2 ± 59.0 and 159.4 ± 40.7 mg/L, p = 0.055). Their CRAE and CRVE were not different before and after antibiotic treatment (p = 0.96, p = 0.78). Hospital inpatients with severe infections had retinal venular calibre that decreased as their infections resolved and CRP levels fell after antibiotic treatment. The changes in venular calibre with intercurrent infections may confound
retinal vascular assessments of, for example, blood pressure control and cardiac risk
Shift towards large-calibre axons in the long-term observation.
No full textHistological analyses were performed on light microscopic level in the sciatic nerve as demonstrated in representative peripheral nerve cross sections. In contrast to WT controls, untreated CMT1A rats showed a loss of large-calibre axons (orange arrow) combined with a hypomyelination of predominantly large axons (green arrow) and a hypermyelination of predominantly small-calibre axons (blue arrow). A higher number of large-calibre axons appeared after PXT3003 treatment in CMT1A rats, without obvious differences between hypo- and hypermyelinated axons (A). Quantification of myelinated axons confirmed axonal loss in CMT1A controls not being affected by PXT3003 treatment (B; WT controls 9003±114, CMT1A controls 8654±74, CMT PXT3003-3 8727±68); however PXT3003 partially corrected the reduced mean axon diameter (C; WT controls 4.96±0.19, CMT1A controls 3.66±0.09, CMT PXT3003-2 3.97±0.08). More detailed analyses of axon calibre distribution confirmed an obvious loss of large-calibre axons in CMT1A rats, and a shift towards large-calibre axons after PXT3003 treatment (D). Mid- and large-calibre axons were corrected towards the wildtype situation as illustrated in more detail for 3–4μm and 5–6μm axons (E and F; WT controls 11.33±1.48, CMT1A controls 26.50±1.08, CMT PXT3003-3 22.44±1.43 and WT controls 21.83±1.54, CMT1A controls 11.11±1.12, CMT PXT3003-2 15.62±1.13, respectively). (ns = not significant, * = p<0.05, **p<0.01 and *** = p<0.001).</p
Increased retinal venular calibre in acute infections
No full textAbstract Population-based studies have demonstrated that increased retinal venular calibre is a risk factor for cardiac disease, cardiac events and stroke. Venular dilatation also occurs with diabetes, obesity, dyslipidemia and autoimmune disease where it is attributed to inflammation. This study examined whether the inflammation associated with infections also affected microvascular calibre. Participants with infections and CRP levels > 100 mg/L were recruited from the medical wards of a teaching hospital and assisted to complete a demographic and vascular risk factor questionnaire, and to undergo non-mydriatic retinal photography (Canon CR5-45NM, Japan). They were then treated with appropriate antibiotics, and underwent repeat retinal imaging when their CRP levels had fallen to less than 100 mg/L. Retinal images were examined for arteriole and venular calibre using validated semi-automated software based on Knudtson’s modification of the Parr-Hubbard formula (IVAN, U Wisconsin). Differences in inflammatory markers and calibre were examined using the paired t-test for continuous variables. Determinants of calibre were calculated from multiple linear regression analysis. Forty-one participants with respiratory (27, 66%), urinary (6, 15%), skin (5, 12%), or miscellaneous (3, 7%) infections were studied. After antibiotic treatment, participants’ mean CRP levels fell from 172.9 ± 68.4 mg/L to 42.2 ± 28.2 mg/L (p 100 mg/L that persisted at review (199.2 ± 59.0 and 159.4 ± 40.7 mg/L, p = 0.055). Their CRAE and CRVE were not different before and after antibiotic treatment (p = 0.96, p = 0.78). Hospital inpatients with severe infections had retinal venular calibre that decreased as their infections resolved and CRP levels fell after antibiotic treatment. The changes in venular calibre with intercurrent infections may confound retinal vascular assessments of, for example, blood pressure control and cardiac risk
Brockman syncline 4 - Primary crushing facility
No full textThis report presents the research and work completed by the author during completion of a 16 week Internship as part requirement of the completion of a Bachelor of Engineering with Murdoch University. Incorporating the project work surrounding the design and implementation phase of a green-field project for a client in the iron ore industry. The name of the project/plant being constructed is Brockman Syncline No.4 and the tasks associated with the project undertaken relates to Instrumentation and Control. This report provides background to the project and an overview of the area of focus whist providing more in-depth research in the particular area to provide the reader with a sound background and knowledge into the operation of the equipment in the plant. Other aspects of the project and associated tasks are also presented including the allocation of the IO in the distributed IO system implementation and also the testing practices for testing of PLC code written by other engineers in the team. Whilst the tasks undertaken throughout the internship are broad they are linked by the work being completed simultaneously by the other members of the team
Venous calibre reduction after intermittent pneumatic compression
No full textObjective: To evaluate the effect of intermittent pneumatic compression (IPC) on venous calibre.
Methods: A total of 28 subjects were divided into three groups: 15 with venous insufficiency (Var), six with lymphoedema (Lym) and seven healthy (Hlt) subjects. One of each patient's lower limbs were treated with IPC. Both limbs were assessed by a duplex scanner, before and after the treatment, and the calibres were then compared.
Results: A significant decrease in the venous calibre was observed only on the treated limbs. The veins affected were: in the Lym group, the lesser saphena (P < 0.05); in the Var group, the greater saphena at its cross (P < 0.01), the lesser saphena (P < 0.02) and the superficial femoral vein (P < 0.05).
Conclusion: A 40 mmHg IPC was sufficient to enhance some venous tonus, especially in subjects with venous insufficiency, for 15-30 min after the 30 min of treatment. (c) 2005 Royal Society of Medicine Press
Plasminogen activator inhibitor-1 (PAI-1) activity and retinal vascular calibre in type 2 diabetes
No full textObjective: To describe relationships of retinal vascular calibre with plasminogen activator inhibitor-1 (PAI-1) and other cardiovascular risk factors in people with type 2 diabetes. Methods: Werecruited 112 community-based persons aged 44–83 years with type 2 diabetes, photo-documented retinal status using a digital fundus camera, and measured traditional and novel vascular risk factors. Retinal arteriolar and venular calibre and the arterio–venous ratio (AVR) were determined from fundus photographs using a validated computer-assisted method. Results: In adjusted linear regression models, PAI-1 activity was strongly associated with all measures of retinal vascular calibre: positively with arterioles ( p = 0.005) and AVR ( p = 0.001), and inversely with venules ( p = 0.001). In addition, wider arterioles were independently associated with waist-hip ratio ( p < 0.0001), HDL-C ( p = 0.015), and lower systolic blood pressure ( p = 0.042), whereas narrower venules were associated with older age and a higher albumin excretion rate. Neither arteriolar nor venular calibre was associated with plasma total homocysteine or C-reactive protein concentration. Conclusion: Retinal vascular calibre is independently associated with PAI-1 activity in type 2 diabetes. This finding supports a role for PAI-1 activity in the microvasculature of persons with type 2 diabetes and may explain the link between retinal vascular calibre and cardiovascular disease. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.
Relationships between airway hyperresponsiveness, inflammation, and calibre in asthma
No full textPrevious studies have focused upon the relationship between airway inflammation and hyperresponsiveness with different conclusions. We re-examined the relationship between airway inflammation (FENO), hyperresponsiveness to methacholine (AHR), and calibre (FEV1 % predicted) in mild-to-moderate asthmatics.We searched our database for asthmatics who had attended our research department. FEV1 % predicted, FENO, and methacholine PC20 were collected. Patients were divided into groups based upon AHR as follows: severe (< 0.5 mg/ml, group A), moderate (> 0.5-2 mg/ml, group B), and mild (> 2-8 mg/ml, group C), and upon FENO: low (< 25 ppb, group D), medium (25-50 ppb, group E), and high (> 50 ppb, group F).In 208 asthmatics, when stratified by AHR, there was an 8.5% difference in FEV1 % predicted (95% CI 2.6-14.4%; P = 0.002) and a 29% difference in FENO between groups A and C (95% CI 2-48%; P = 0.034). When stratified by FENO, there was a 1.29 doubling dilution difference in methacholine PC20 (95% CI 0.26-2.33; P = 0.009) between groups D and F. There was no difference between FEV1 % predicted when grouped by FENO. Multivariate regression analysis with covariates, including inhaled corticosteroids, supported our findings from categorical analysis.We found no relationship between airway inflammation and calibre, whilst showing significant relationships between AHR and airway calibre and AHR and airway inflammation. Whilst relationships exist, the lack of complete concordance highlights the important role each contributes to the assessment of the asthmatic individual.</p
Modelamiento de la relación calibre, humedad y contenido de aceite en palta HASS (Persea americana) de descarte por bajo calibre para la elaboración de pulpa
No full textEl descarte de palta Hass debido al bajo calibre genera grandes pérdidas
económicas a las empresas dedicadas a su cultivo y exportación. Dependiendo
de su contenido de aceite, estos frutos pueden ser destinados a la extracción de
aceite (mayor 15%) o a la producción de pulpa. La determinación del %CA en
pulpa de palta resulta un procedimiento caro y largo, por lo que es necesario
establecer una relacion entre parámetro y medidas como la humedad y el calibre
que son más económicas, fáciles y rápidas. El objetivo de este estudio fue
establecer un modelo matemático que relacione el calibre, la humedad y el
contenido de aceite en palta HASS de descarte por bajo calibre, para su uso como
parámetro de selección para su destino en la elaboración de pulpa o extracción
de aceite.
El estudio determinó que existe una relación entre el calibre, la humedad y el
contenido de aceite en la palta Hass, descrita por la ecuación:
%CA=5.907+0.187(Cal)+0.039(Cal)2-9.661(%H)-0.053(%H)2+0.069(Cal)(%H).
Utilizando el modelo, se determinó que las paltas de bajo calibre son aptas para
su uso en la elaboración de pulpa ya que ésta equivale a un 79% de su peso y
posee un %CA entre 7 y 15%, que es el ideal para la producción de pulpa.
Finalmente, en la optimización del proceso de escalado de pulpa de palta de
descarte, se determinó que E5 (75°C/ 10 minutos) fue el mejor tratamiento, dado
que no alteró significativamente los sabores originales de la fruta, logró inhibir la
PPO por lo que el color, pH y acidez se mantuvieron constantes por más tiempo,
en comparación.Tesi
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