Browsing by Author "Pereira, P"
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- Accelerated age-related olfactory decline among type 1 Usher patientsPublication . Ribeiro, JC; Oliveiros, B; Pereira, P; António, N; Hummel, T; Paiva, A; Silva, EUsher Syndrome (USH) is a rare disease with hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. A phenotype heterogeneity is reported. Recent evidence indicates that USH is likely to belong to an emerging class of sensory ciliopathies. Olfaction has recently been implicated in ciliopathies, but the scarce literature about olfaction in USH show conflicting results. We aim to evaluate olfactory impairment as a possible clinical manifestation of USH. Prospective clinical study that included 65 patients with USH and 65 normal age-gender-smoking-habits pair matched subjects. A cross culturally validated version of the Sniffin' Sticks olfaction test was used. Young patients with USH have significantly better olfactory scores than healthy controls. We observe that USH type 1 have a faster ageing olfactory decrease than what happens in healthy subjects, leading to significantly lower olfactory scores in older USH1 patients. Moreover, USH type 1 patients showed significantly higher olfactory scores than USH type 2, what can help distinguishing them. Olfaction represents an attractive tool for USH type classification and pre diagnostic screening due to the low cost and non-invasive nature of the testing. Olfactory dysfunction should be considered among the spectrum of clinical manifestations of Usher syndrome.
- Cholesterol oxides accumulate in human cataractsPublication . Girão, H; Mota, MC; Ramalho, J; Pereira, PHuman lens membranes contain the highest cholesterol content of any known biological membrane. Although cholesterol is prone to oxidation, the presence of its oxidation products in human cataract has not been shown before. This study was designed to investigate the presence of cholesterol oxides in human cataractous lenses. Human clear lenses (n = 48) were obtained from Coimbra University Hospital Eye Bank. Human cataracts (n = 54) were obtained by routine extracapsular surgery. Cholesterol oxides were isolated by solid-phase extraction on a C18 cartridge and quantified as TMS-ether derivatives by gas chromatography. The extraction procedure allows for an efficient recovery of the major cholesterol oxides, while retaining virtually all cholesterol. Exposure of membranes isolated from transparent human lenses to the free radical generator 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH) produced 7 alpha-hydroxycholesterol (6%), 7 beta-hydroxycholesterol (19%), 5 alpha, 6 alpha-epoxycholestanol (1%) and 7-ketocholesterol (74%) as major oxidation products. Cataractous lenses contained quantifiable amounts of 7 beta-hydroxycholesterol (7.3 +/- 0.74 mmol mol-1 cholesterol), 7-ketocholesterol (4.2 +/- 0.32 mmol mol-1 cholesterol), 5 alpha, 6 alpha-epoxycholestanol (0.9 +/- 0.16 mmol mol-1 cholesterol), 20 alpha-hydroxycholesterol (0.6 +/- 0.13 mmol mol-1 cholesterol) and 25-hydroxycholesterol (0.1 +/- 0.02 mmol mol-1 cholesterol), whereas clear lenses contained no detectable amounts of cholesterol oxides. We have shown, for the first time, that oxysterols accumulate in human cataracts. Although the total amount of oxidized cholesterol in cataracts is not likely to be high it may account for much of the membrane damage associated with cataract formation.
- Ultrasound-guided central venous catheterization ---‘‘Syringe-Free’’ approachPublication . Matias, F; Semedo, E; Carreira, C; Pereira, PBackground and objectives Central venous catheterization of the internal jugular vein is a commonly performed invasive procedure associated with a significant morbidity and even mortality. Ultrasound-guided methods have shown to significantly improve the success of the technique and are recommended by various scientific societies, including the American Society of Anesthesiologists. The aim of this report is to describe an innovative ultrasound-guided central line placement of the internal jugular vein. Technique The authors describe an innovative ultrasound-guided central line placement of the internal jugular vein based on an oblique approach – the “Syringe-Free” approach. This technique allows immediate progression of the guide wire in the venous lumen, while maintaining a real-time continuous ultrasound image. Conclusions The described method adds to the traditional oblique technique the possibility of achieving a continuous real-time ultrasound-guided venipuncture and a guide wire insertion that does not need removing the probe from the puncture field, while having a single operator performing the whole procedure.