Biomedical subjects

Katayoun Vahedi

Publications and source records attributed to Katayoun Vahedi.

6 recordsLinked to original sources

PubMed2006

Characteristic features of in vivo skin microvascular reactivity in CADASIL.

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) is caused by mutations in the Notch3 receptor expressed at the surface of vascular smooth muscle cells. The functional consequences of the disease at the peripheral microcirculation level are incompletely elucidated. In this study, we aimed to assess, in vivo, the endothelium-dependent and independent vasodilation of the skin microvasculature in CADASIL patients. Twenty-three affected subjects were compared with 23 gender and age-matched controls. The brachial artery endothelium-dependent and endothelium-independent vasodilation were assessed after forearm cuff occlusion and nitroglycerin administration. Skin vasoreactivity to transcutaneous administration of acetylcholine and sodium nitroprussiate, and after postocclusive hyperemia were measured by Laser Doppler flowmetry. The maximum changes in the diameter of the brachial artery after the cuff release or after nitroglycerin administration did not differ between patients and controls. With iontopheresis, only the peak value of the dose response was found decreased in normocholesterolemic patients after nitroprussiate administration. The postocclusive test revealed a large increase of the time to peak value and whole duration of the hyperemic response in CADASIL patients. The results of this study show that the skin vasoreactivity is altered in CADASIL. Particularly, the kinetics of reactive hyperemia after cuff occlusion is dramatically changed with a lengthened and delayed response. This characteristic pattern may be related to the specific ultrastructural modifications related to Notch3 gene mutations involving smooth muscle cells in the microvasculature.

Adult↗

PubMed2006

Role of COL4A1 in small-vessel disease and hemorrhagic stroke.

Small-vessel diseases of the brain underlie 20 to 30 percent of ischemic strokes and a larger proportion of intracerebral hemorrhages. In this report, we show that a mutation in the mouse Col4a1 gene, encoding procollagen type IV alpha1, predisposes both newborn and adult mice to intracerebral hemorrhage. Surgical delivery of mutant mice alleviated birth-associated trauma and hemorrhage. We identified a COL4A1 mutation in a human family with small-vessel disease. We concluded that mutation of COL4A1 may cause a spectrum of cerebrovascular phenotypes and that persons with COL4A1 mutations may be predisposed to hemorrhage, especially after environmental stress.

Animals↗

PubMed2006

Electrocardiogram in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy patients without any clinical evidence of coronary artery disease: a case-control study.

BACKGROUND AND PURPOSE: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited systemic arteriopathy caused by highly stereotyped mutations in NOTCH3. The clinical expression of CADASIL is confined to the central nervous system with characteristic recurrent subcortical infarcts and vascular dementia. However, cases have been reported with associated circulatory small vessel abnormalities in the retina or the myocardium and with myocardial infarction. Classical cardiovascular risk factors may influence such circulatory abnormalities. Thus, we conducted a case control study to determine the frequency of electrical abnormalities on a 12-lead resting ECG in CADASIL patients without classical atherosclerotic risk factors. METHODS: Twenty-three CADASIL patients (mean age+/-SD; 55.1+/-11 years) free of any classical cardiovascular risk factors except for hypercholesterolemia were recruited from 1 neurology department and compared with 23 sex- and age-matched healthy controls (mean age+/-SD; 54.7+/-9.5 years). A resting supine 12-lead ECG was recorded at inclusion and analyzed later by 2 reviewers. Signs of myocardial infarction or ischemia, conduction, and rhythm disturbances were looked for. RESULTS: We found no ECG sign evoking myocardial infarction or myocardial ischemia. CADASIL patients had, compared with healthy controls, a significantly higher heart rate and a significantly lower Sokolow index, but these values remained in the normal ranges. CONCLUSIONS: In this case-control study, we found no ECG evidence for myocardial infarction or ischemia, conduction disturbances, or arrhythmias in CADASIL patients compared with healthy controls.

Adult↗

PubMed2004

Migraine with aura and brain magnetic resonance imaging abnormalities in patients with CADASIL.

BACKGROUND: Migraine with aura (MA) is one of the clinical hallmarks of CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), a small vessel disease of the brain caused by mutations in the NOTCH3 gene, but its exact mechanisms are unknown. OBJECTIVES: To describe the patterns of MA in CADASIL and to compare brain magnetic resonance signal abnormalities between CADASIL patients with and without MA. DESIGN: Comparison of brain magnetic resonance signal abnormalities between cases and controls. SETTING: Patients with CADASIL seen at Lariboisière Hospital. PATIENTS: Forty-one CADASIL patients with MA and 31 age-matched CADASIL controls without MA. RESULTS: The mean age at onset of MA was significantly younger in women compared with men and occurred a mean of 15 years prior to stroke onset. A majority of patients (56%) reported at least 1 migraine attack with atypical aura. All CADASIL patients either with or without MA had white matter signal abnormalities on T2-weighted imaging. There was no difference in the frequency and distribution of brain signal abnormalities between CADASIL patients with and without MA. CONCLUSIONS: In CADASIL, MA is characterized by an unusually high frequency of attacks of migraine with atypical aura. The distribution and extent of magnetic resonance signal abnormalities did not differ according to migraine phenotype.

Adult↗

PubMed2003

Uncontrollable high-frequency tachypnea in a case of unilateral medial medullary infarct.

BACKGROUND: Medullary infarcts can be associated with breathing disorders that usually consist in central hypoventilation. PATIENT: We describe the case of a 54-year-old man, fully conscious, presenting with an uncontrollable high frequency and shallow tachypnea (95/min) at the onset of a unilateral medial medullary infarct. This disorder disappeared under inspiratory pressure support mechanical ventilation. MEASUREMENTS AND RESULTS: Respiratory drive (respiratory rate, occlusion pressure, and mean inspiratory flow), efferent pathway (transcranial and cervical magnetic stimulation), and afferent pathway (response to CO(2) and to lung inflation) were investigated. The respiratory drive was increased. The phrenic nerve conduction time was normal. The sensitivity of the central pattern generator to lung inflation and to CO(2) was preserved. The territory of the infarct was supplied by the spinal anterior artery. CONCLUSIONS: An extremely rapid and shallow tachypnea due to the increase in respiratory drive can be associated with unilateral medullary infarction.

Cerebral Infarction↗

PubMed2002

Thrombolysis in stroke.

The ability to use an effective treatment constitutes a main concern in the management of acute ischemic stroke. Randomized trials have so far failed to demonstrate any beneficial effect of neuroprotective agents on neurologic outcome after an acute stroke. Thrombolytic agents can achieve early recanalization of an occluded intracerebral artery. The benefit of their use in ischemic stroke has been assessed in several randomized trials involving more than 5,000 patients. Among them, a single randomized trial, the National Institute of Neurological Diseases and Stroke Trial, showed a beneficial effect of thrombolysis on outcome after an acute ischemic stroke with a significant increase in the number of patients with no or minimal disability at 3 months in the group receiving intravenous recombinant tissue plasminogen activator (rt-PA) compared with placebo. However, there was no reduction in mortality and there was, as in all other trials, a significant increase in the risk of symptomatic intracerebral hemorrhage (ICH).

Acute Disease↗