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Biomedical subjects

M J Miranda

Publications and source records attributed to M J Miranda.

10 recordsLinked to original sources
PubMed2006

[Neuroimaging in preterm infants].

INTRODUCTION: It is today well recognised that preterm infants are at risk of neurodevelopmental impairments later in life. The preterm brain is exposed to different stimuli that may affect its normal development. Develoment. Magnetic resonance imaging (MRI) offers the possibility of monitoring normal brain development and pathology in the preterm brain. The most frequent lesions are germinal matrix/intraventricular haemorrhages, periventricular hemorrhagic infarction and periventricular leukomalacia. Other changes especially in the white matter, less well known from ultrasound studies, can be depicted with MRI. Furthermore, quantitative MRI techniques have demonstrated differences between the normal appearing preterm brain at term-equivalent age and the brain of term-born infants. CONCLUSION: These studies confirm that the immature brain may develop differently in the extra uterine environment. Future studies with these techniques will improve our knowledge of the effects of prematurity on long term brain development.

Brain↗
PubMed2006

[Pressure ulcer management--Evidence-based interventions].

Despite improved awareness and quality of care among health care personnel, pressure ulcers prevalence remains high especially in the inpatient setting. Pressure ulcers are associated with increased morbidity and mortality, affecting the quality of life of patients and their caregivers, and significantly increasing direct and indirect healthcare costs. Early risk assessment for developing a pressure ulcer is essential to decide on the appropriate preventive measures and for initiation of a tailored therapeutic approach. Interventions include strategies to reduce extrinsic and intrinsic risk factors associated with tissue ischemia, optimization of patient's nutritional status, and local wound care. This revision intends to review current evidence-based therapeutic interventions in pressure ulcer care, and support implementation of management protocols in an inpatient ward.

Anti-Bacterial Agents↗
PubMed2002

Visual cortex reactivity in sedated children examined with perfusion MRI (FAIR).

Sleeping and sedated children can respond to visual stimulation with a decrease in blood oxygenation level dependent (BOLD) functional MRI signal response. The contribution of metabolic and hemodynamic parameters to this inverse signal response is incompletely understood. It has been hypothesized that it is caused by a relatively greater increase of oxygen consumption compared to rCBF (regional cerebral blood flow) increase. We studied the rCBF changes during visual stimulation in four sedated children, aged 4-71 months, and four alert adults, with an arterial water spin labeling technique (FAIR) and BOLD fMRI in a 1.5T MR scanner. In the children, FAIR signal decreased by a mean of 0.96% (range 0.77-1.05) of the baseline periods of the non-selective images, while BOLD signal decreased by 2.03% (range 1.99-2.93). In the adults, FAIR and BOLD signal increased by 0.88% (range 0.8-0.99) and 2.63% (range 1.99-2.93), respectively. Thus, in the children, an rCBF increase could not be detected by perfusion MRI, but indications of a FAIR signal decrease were found. An rCBF decrease in the primary visual cortex during stimulation has not been reported previously, but it is a possible explanation for the negative BOLD response. Future studies will have to address if this response pattern is a consequence of age or sleep/sedation.

Adult↗
PubMed2000

Functional magnetic resonance imaging of the normal and abnormal visual system in early life.

Functional magnetic resonance imaging (fMRI) in young children may provide information about the development of the visual cortex, and may have predictive value for later visual performance. The purpose of this study was to evaluate the usefulness of fMRI for examining cerebral processing of vision in very young infants and in infants with brain damage. We examined 15 preterm infants, 12 children suspected of having a cerebral visual impairment and 10 children with a normal visual system, all of whom were either spontaneously asleep or sedated with chloral hydrate. Cortical response to stroboscopic light stimulation could be demonstrated in all technically acceptable data sets from children with a post-menstrual age (PMA) of > 41 weeks, but not in younger infants. Children < 60 weeks PMA showed either a blood oxygenation level-dependent (BOLD) signal increase or decrease, while all older children showed a signal decrease. The activated cortical volumes showed a linear relation to age for healthy children younger than 90 weeks PMA, but were small in children with visual impairment. In two children with unilateral damage to the optic radiations, activation was strongly asymmetrical with greatest activation on the healthy side. In future prospective studies, results from the period from birth to six months of age should be interpreted with caution, as inter-individual variation of cortical development may be confused with functional deficit.

Blindness, Cortical↗
PubMed1998

Visual activation in infants and young children studied by functional magnetic resonance imaging.

The purpose of this study was to determine whether visual stimulation in sleeping infants and young children can be examined by functional magnetic resonance imaging. We studied 17 children, aged 3 d to 48 mo, and three healthy adults. Visual stimulation was performed with 8-Hz flickering light through the sleeping childs' closed eyelids. Functional magnetic resonance imaging was performed with a gradient echoplanar sequence in a l.5-T magnetic resonance scanner. Six subjects were excluded because of movement artifacts; the youngest infant showed no response. In 10 children, we could demonstrate areas of signal decrease during visual stimulation in the occipital cortex (mean decrease 2.21%), contrary to the signal increase observed in the adult controls (mean increase 2.82%). This decrease may be due to a higher proportional increase in oxygen extraction compared with increase in cerebral blood flow during activation. The different response patterns in young children and adults can reflect developmental or behavioral differences. Localization of the activation seemed to be age-dependent. In the older children and the adults, it encompassed the whole length of the calcarine sulcus, whereas it was restricted to the anterior and medial part of the calcarine sulcus in the younger infants. This may reflect a different functional organization of the young child's visual cortex or the on-going retinal development.

Adult↗
PubMed1997

Anophthalmia-microphthalmia-oblique clefting syndrome: confirmation of the Fryns anophthalmia syndrome.

We describe a patient with bilateral extreme microphthalmia with bilateral congenital glaucoma, bilateral medial oblique facial cleft ending in lid colobomas, bilateral stenosis of the choanae, bifid uvula, frontal encephalocele, and premature craniosynostosis. The cause is unknown, but the phenotype resembles the Fryns anophthalmia-plus syndrome, which may be a recessive trait, although intrauterine environmental factors cannot be excluded.

Abnormalities, Multiple↗
PubMed1995

[Non-immunological hydrops fetalis].

Hydrops foetalis is an uncommon condition, occurring in 1/1400-1/4000 of all pregnancies. The possible etiologies to the disease are numerous and up to now the prognosis has been very dull, with a mortality-rate of 40-90%. A successfully treated case story is presented. It is concluded, that it is essential from the very beginning to treat the child aggressively to restore normal respiratory and circulatory function. When this is performed the child will have a good chance of surviving and developing normally.

Female↗
PubMed1995

[Efficacy of repeat coronary dilatation in patients with restenosis of the anterior descending artery].

PURPOSE: To analyze the clinical characteristics, acute and long term results of repeat percutaneous transluminal coronary angioplasty (PTCA) for restenosis of the proximal left anterior descending coronary artery (LDA) METHODS: We studied 113 patients, 79% male, mean age 59 years, 49.5% had stable angina, with single vessel proximal LDA disease undergoing repeat PTCA for a first restenosis from January/88 to December/92. We examined the in hospital outcome (success rate and complications) and long term follow up (angina status, occurrence of myocardial infarction (MI), death and need for repeat PTCA or coronary artery bypass graft (CABG) of this subgroup. RESULTS: Primary success was 96%. Complications included: 1% MI, 1% emergency CABG and 1% procedural death. Follow up data (mean 42 months) was available in 102 (94%) out of 109 patients with successful repeat PTCA: 64 (63%) patients were asymptomatic, 5 (5%) had a MI and 28 (27%) required repeat PTCA or CABG. Actuarial 5 year freedom from death was 94%, freedom from death and MI was 91% and freedom from death, MI and repeat PTCA or CABG was 52%. CONCLUSION: Repeat PTCA is an effective treatment for proximal LAD restenosis with a high success rate, low incidence of procedural complications and provides excellent long term cardiac survival, however repeat revascularization is frequently required.

Actuarial Analysis↗