Route Planning Process by the Endangered Black Lion Tamarin in Different Environmental Contexts.

Daily, primates take a variety of decisions to establish why, when, and where to move. However, little is known about the factors influencing and shaping primate daily routes. We investigated the decision-making processes linked to route planning in four groups of black lion tamarins (BLT-Leontopithecus chrysopygus).

Potential role in seed dispersal revealed by experimental trials with captive southern muriquis (Brachyteles arachnoides).

Primates are great fruit consumers and disperse intact seeds from most of the plants they consume, but effective seed dispersal depends, amongst other factors, on handling behavior. Likewise, the treatment in gut and mouth may alter seed fate. Overall, frugivore and folivore-frugivore primates are recognized to provide beneficial gut treatment for Neotropical plant species, but this effect might be overlooked at species-specific levels.

Maternal near miss and death among women with severe hypertensive disorders: a Brazilian multicenter surveillance study.

Background: Hypertensive disorders represent the major cause of maternal morbidity in middle income countries. The main objective of this study was to identify the prevalence and factors associated with severe maternal outcomes in women with severe hypertensive disorders.

Methods: This was a cross-sectional, multicenter study, including 6706 women with severe hypertensive disorder from 27 maternity hospitals in Brazil.

[Influence of season on bone mineral densitometry].

Objective: In places where sun exposure during the winter is limited, bone mineral density (BMD) may present seasonal variations, increasing during the summer and decreasing during the winter period. There have been suggestions that this variation could influence prospective evaluations of BMD studies. The aim of this study was to evaluate if the seasons of the year (summer/winter) are associated to variations in BMD values.

Transcranial Doppler in the diagnosis of cardiac patent foramen ovale.

Right-to-left shunt due to patent foramen ovale is a well-established risk factor for ischemic stroke, especially in young subjects and in patients with cryptogenic stroke. We report a detailed method for the diagnosis of a right-to-left shunt by means of transcranial Doppler as established at a recent consensus conference, and review the literature on the indications for the test.

Detection of right-to-left shunt with ultrasound contrast agent and transcranial Doppler sonography.

An international Consensus Meeting to determine a standard in the examination technique for the detection of right-to-left shunt (RLS) using contrast transcranial Doppler sonography (TCD) led to the following recommendations to standardize the examination procedure: The patient should be prepared with an 18-gauge needle inserted into the cubital vein and should be in the supine position. Insonation of at least one middle cerebral artery (MCA) using TCD is performed. The contrast agent is prepared using 9 ml isotonic saline solution and 1 ml air mixed with a three-way stopcock by exchange of saline/air mixture between the syringes and injected as a bolus.

Morphological and functional characteristics of patent foramen ovale and their embolic implications.

Background And Purpose: Transesophageal echocardiography (TEE) has detected a high prevalence of patent foramen ovale (PFO) in stroke patients, but the clinical implications of the distinctive characteristics of this patency are still a matter of debate.

Methods: We studied 350 patients with acute ischemic stroke or transient ischemic attack (TIA) within 1 week of admission. Of these, 101 (29%) were identified by contrast TEE to have a PFO; 86 patients (25%) were cryptogenic stroke patients, and 163 were excluded because of the presence of a definite or possible arterial or clinical evidence of a source of emboli or small-vessel disease.

Early spontaneous improvement and deterioration of ischemic stroke patients. A serial study with transcranial Doppler ultrasonography.

Background And Purpose: The purpose of our study was to investigate whether emergency transcranial Doppler (TCD) findings and their modifications over the first 48 hours are related to early neurological changes in acute ischemic stroke patients.

Methods: Ninety-three patients underwent CT scan within 5 hours of a first-ever ischemic hemispheric stroke, and TCD serial examinations at 6, 24, and 48 hours after stroke onset. We classified TCD findings as follows: normal; middle cerebral artery (MCA) asymmetry (asymmetry index between affected and contralateral MCAs below -21%); and MCA no-flow (absence of flow signal from the affected MCA in the presence of ipsilateral anterior and posterior cerebral artery signals through the same acoustic window).

Dopamine hypersensitivity in migraine: role of the apomorphine test.

We investigated the effects of apomorphine administration at two different doses (2-10 micrograms/kg, s.c.) in 35 migraineurs in headache-free period and in 20 age-matched healthy control subjects, with and without pretreatment with domperidone.

Correlates of leukoaraiosis and ventricular enlargement on magnetic resonance imaging: a study in normal elderly and cerebrovascular patients.

Several studies have repeatedly demonstrated that leukoaraiosis as well as ventricular enlargement are common findings in normal elderly and in stroke patients, although there is no general consensus on prevalence rate as well as on their clinical correlations. It is also controversial whether white matter changes and ventricular enlargement are reciprocally related. In this study we investigated the prevalence and extent of white matter hyperintensities and the degree of ventricular enlargement on magnetic resonance imaging in 50 normal elderly individuals (mean age 62.

Patent foramen ovale and transcranial Doppler. Comparison of different procedures.

Background And Purpose: The capability of transcranial Doppler sonography (TCD) to detect a patent foramen ovale (PFO) has been established. However, which provocative maneuver and what timing of contrast injection are most effective to induce a right-to-left shunt has not yet been determined.

Methods: We selected 38 cerebrovascular patients (21 men, 17 women) with positive contrast study for PFO on transesophageal echocardiography.

Clinical and prognostic correlates of stroke subtype misdiagnosis within 12 hours from onset.

Background And Purpose: Pure motor hemiparesis and sensorimotor stroke syndromes are not accurate predictors of lacunar infarct when described in the first 12 hours of stroke onset. We evaluate here whether this inaccuracy of clinical diagnosis might have influenced the planning of patient management either in routine practice or in therapeutic trials.

Methods: A consecutive hospital series of 517 first-ever ischemic hemispheric stroke patients presented lacunar or nonlacunar syndromes at the first examination within 12 hours of the event.

High-quality compression of echographic images by neural networks and vector quantisation.

A compression method is presented for medical images based on neural networks and vector quantisation (VQ). The neural net is a perceptron and it is followed by some expressly designed VQ algorithms. The method devotes special attention to the quality of the reconstructed images and to the reduction of artefacts.

Prevalence and outcome of symptomatic carotid lesions in young adults. National Research Council Study Group.

Objective: To estimate the prevalence and outcome of symptomatic internal carotid artery lesions in young adults.

Design: Multicentre hospital based observational study with five year follow up.

Setting: Seven neurological departments in northern and central Italy.

Spontaneous middle cerebral artery reperfusion in ischemic stroke. A follow-up study with transcranial Doppler.

Background And Purpose: The aim of this study was to investigate by means of transcranial Doppler (TCD) ultrasonography how many spontaneous reperfusions of the middle cerebral artery (MCA) occurred during the first week after onset of acute ischemic stroke in the carotid territory.

Methods: TCD examination, computed tomographic scan, and arterial digital angiography were performed in 56 patients with acute ischemic stroke within 6 hours of the onset of symptoms. The TCD examination was repeated within 24 hours, 48 hours, and 7 days after stroke; a further TCD examination was performed within 3 to 9 months in 27 patients.

Transcranial Doppler in spontaneous attacks of migraine.

Background And Purpose: Our aim in this study was to compare headache-free and spontaneous migraine measurements of blood flow velocity and the pulsatility index in the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery.

Methods: Thirty-one patients (nine having experienced migraine with aura and 22 migraine without aura) were studied in headache-free periods and during spontaneous migraine attacks with transcranial Doppler ultrasonography.

Results: During attacks of migraine with aura, blood flow velocities (particularly the diastolic velocity [p = 0.

Transcranial Doppler (TCD) after nitroglycerin in migraine without aura.

Nitroglycerin, a vasodilating agent, was administered sublingually in migraine without aura patients and in healthy volunteers. Systolic, diastolic and time-mean flow velocity and pulsatility index, were measured by transcranial Doppler sonography in the major intracranial arteries before and after nitroglycerin administration. Following nitroglycerin administration, a significant decrease in systolic and time-mean velocity and pulsatility index was observed in migraine patients, whereas in control subjects only time-mean velocity decreased significantly.

Transcranial Doppler in acute hemispheric brain infarction.

We studied cerebrovascular anatomy using intra-arterial digital angiography, and blood flow velocity in the middle cerebral artery (MCA) using transcranial Doppler (TCD) ultrasonography in 42 patients with acute hemispheric ischemic brain infarction. We compared angiography with TCD and the clinical findings within 6 hours of the onset of symptoms. The location and extent of the chronic ischemic brain damage was assessed by CT performed 1 to 3 months after the ictus.

How to assess acute cerebral ischemia.

There are different approaches to the assessment of acute stroke. Its causes, its severity, and/or its final prognosis may be investigated. The traditional approach is anatomoclinical.

Real-time system for robust spectral parameter estimation in Doppler signal analysis.

In assessing the level of stenosis in extracranial Doppler analysis, spectral analysis has until now been used qualitatively, for the most part. Owing to the many variables affecting the measurements (mainly noise level and instrument setting made subjectively by the operator), the reliability of the inferences on the degree of stenosis is not clearly definable. Under such conditions the need arises for algorithms and systems that can estimate spectral parameters with a higher degree of accuracy, to verify whether reliable inferences can indeed by made or if this technique is only a qualitative one.

Echodensitometry: a methodologic approach to the non-invasive diagnosis of carotid atherosclerotic plaques.

The ultrasound image of the fibroatheromatous plaque has to date been unable to reveal the presence or absence of complications as shown by histology, such as thrombosis and intraplaque hemorrhage. We propose a novel densitometric method for determining the composition of the plaque at the echotomography, along with a new classification based on mathematical models drawn from the optical density distribution curve. This approach avails of an extremely high sensitivity.

Comparison of cerebral angiography and transcranial Doppler sonography in acute stroke.

We compared digital intra-arterial angiography and transcranial Doppler sonography in acute cerebral ischemia as part of a wider study on a continuous series of 48 patients with acute focal cerebral ischemia in the carotid territory, observed within 4 hours of the onset of symptoms. The most significant Doppler findings of the middle cerebral artery included no detection of the artery when occlusion of the carotid siphon or the middle cerebral artery at its origin was shown by angiography and reduced flow velocities and asymmetry (symptomatic less than asymptomatic) when the occlusion was located in the terminal tract of the middle cerebral artery mainstem or in numerous terminal branches. Higher flow velocities in the anterior cerebral artery or posterior cerebral artery, mostly in the symptomatic hemisphere, often accompanied middle cerebral artery pathology, probably indicating collateral compensatory pathways.