[Influence of age and gender on plasma norepinephrine changes produced by orthostatic stress]

The aim of this work was to determine the effect of aging and gender on plasma norepinephrine (NE) response to orthostatic stress. Fifty-six men and sixty women non-smokers, sedentary, non-obese, were studied at supine and standing positions. On the basis of the age of the subjects, they were divided into three groups of either men or women. Group A, young, range 17-34 years, Group B, middle-age, range 40-60 years, and Group C: senescent, range 61-91 years. Senescent subjects had the highest absolute supine values of NE and significant differences between women and men were found in groups B Men: 298 +/- 15 pg/mL; Women: 348 +/- 14 pg/mL), and C (M: 386 +/- 29 pg/mL; W: 473 +/- 19 pg/mL), but not between young (M: 246 +/- 21 pg/mL; W: 261 +/- 18 pg/mL). NE increased markedly in response to the orthostatic stress but the relative (percentage) increases were smaller in the older subjects perhaps related to their elevated baseline levels. The highest percent positive variation was observed in group A (M: 85%; W: 82%). The oldest group (C), had the lowest variation (M: 23%; W: 21%). The relative increases in NE responses were not different in men and women. The orthostatic-induced variation in NE was negatively related to aging in both men and women (M: r = -0.654; p < 0.0001; W: r = -0.557; p < 0.0001). It is concluded that orthostatic stress induced rise of blood NE is attenuated by age but does not appear to be dependent on gender.

Automatic classification of HITS into artifacts or solid or gaseous emboli by a wavelet representation combined with dual-gate TCD

BACKGROUND AND PURPOSE

Transcranial Doppler (TCD) can detect high-intensity transient signals (HITS) in the cerebral circulation. HITS may correspond to artifacts or solid or gaseous emboli. The aim of this study was to develop an offline automated Doppler system allowing the classification of HITS.

METHODS

We studied 600 HITS in vivo, including 200 artifacts from normal subjects, 200 solid emboli from patients with symptomatic internal carotid artery stenosis, and 200 gaseous emboli in stroke patients with patent foramen ovale. The study was 2-fold, each part involving 300 HITS (100 of each type). The first 300 HITS (learning set) were used to construct an automated classification algorithm. The remaining 300 HITS (validation set) were used to check the validity of this algorithm. To classify HITS, we combined dual-gate TCD with a wavelet representation and compared it with the current "gold standard," the human experts.

RESULTS

A combination of the peak frequency of HITS and the time delay makes it possible to separate artifacts from emboli. On the validation set, we achieved a sensitivity of 97%, a specificity of 98%, a positive predictive value (PPV) of 99%, and a negative predictive value (NPV) of 94%. To distinguish between solid and gaseous emboli, where positive refers now to the solid emboli, we used the peak frequency, the relative power, and the envelope symmetry of HITS. On the validation set, we achieved a sensitivity of 89%, a specificity of 86%, a conditional PPV of 89%, and a conditional NPV of 89%.

CONCLUSIONS

An automated wavelet representation combined with dual-gate TCD can reliably reject artifacts from emboli. From a clinical standpoint, however, this approach has only a fair accuracy in differentiating between solid and gaseous emboli.

Matrix metalloproteinase expression after human cardioembolic stroke: temporal profile and relation to neurological impairment

BACKGROUND AND PURPOSE

Uncontrolled expression of matrix metalloproteinases (MMPs) can result in tissue injury and inflammation. In animal models of cerebral ischemia, the expression of MMP-2 and MMP-9 was significantly increased. However, their role in human stroke in vivo remains unknown. Therefore, we sought to determine the temporal profile of MMP expression in patients with acute ischemic stroke and to investigate its relationship to stroke severity, location of arterial occlusion, and total infarct volume.

METHODS

Serial MMP-2 and MMP-9 determinations were made in 39 patients with cardioembolic strokes that involved the middle cerebral artery territory by means of enzyme-linked immunosorbent assay. Blood samples, transcranial Doppler recordings, and National Institutes of Health Stroke Scale (NIHSS) scores were obtained at baseline and at 12, 24, and 48 hours after stroke onset. Infarct volume was measured with CT scanning at 48 hours.

RESULTS

No correlation was found between MMP-2 and NIHSS score at any time point, although a close relation appeared between mean MMP-9 and final NIHSS score (r=0.486, P=0.002). MMP-9 value was the only factor associated with the final NIHSS score in the multiple logistic regression model (OR 4.54, 95% CI 1.5 to 13.75). A cut-point of MMP-9 142.18 ng/mL had a positive predictive value of 94.4% to assess a patient's NIHSS (<8 or >/=8) by the end of the study. Final MMP-2 and MMP-9 levels were significantly lower when recanalization occurred (528+/-144.3 versus 681.4+/-239.2 ng/mL, P=0.031 for MMP-2; 110.2+/-100.9 versus 244.8+/-130 ng/mL, P=0.004 for MMP-9). A positive correlation was found between mean MMP-9 and infarct volume (r=0.385, P=0.022).

CONCLUSIONS

MMPs are involved in the acute phase of human ischemic stroke. MMP-9 levels are associated with neurological deficit, middle cerebral artery occlusion, and infarct volume.

[Correlation between the expression of proinflammatory cytokines and matrix metalloproteinases in the acute phase of an ischemic stroke]

INTRODUCTION

Proinflammatory cytokines are the main responsible for the onset of postischemic inflammatory cascade. Recently, the deleterious effect of matrix metalloproteinases (MMPs) in the acute phase of stroke has been described. Animal models suggest a link between both families.

OBJECTIVE

We aimed to investigate possible relations between the MMP overproduction and proinflammatory cytokine expression after human ischemic stroke.

PATIENTS AND METHODS

From all consecutive stroke patients attended during a 10 months period, we selected and prospectively studied those presenting as a cardioembolic stroke involving the MCA territory. MMP 9, MMP 2 and IL 6 were serially measured by means of ELISA at study entry and at 12, 24 and 48 hours after symptoms onset.

RESULTS

A total of 39 patients were studied. A positive correlation was found between mean expression of both MMPs and IL 6 (r= 0.33, p= 0.040 for MMP 2 y r= 0.45, p= 0.004 for MMP 9). From all measured timepoints, the best obtained correlation was that of MMP 9 with IL 6 at 24 hours (r= 0.418, p= 0.010). At 24 h a peak value of IL 6 was observed. Baseline MMP 2 and MMP 9 levels showed a trend to correlate with that peak of IL 6 (r= 0.329, p= 0.061 for MMP 2 y r= 0.325, p= 0.061 for MMP 9).

CONCLUSION

MMP expression correlates with the inflammatory cascade activation after acute cardioembolic stroke.

Consanguinity and congenital heart disease in Saudi Arabia

First-cousin marriage may be a significant risk factor for specific types of congenital heart disease in a consanguineous population. Inbreeding studies suggest an autosomal recessive component in the cause of some congenital heart defects. We studied a large sample of patients with structural congenital heart defects (CHD) identified through the Congenital Heart Disease Registry at King Faisal Specialist Hospital in Riyadh, Saudi Arabia. After exclusions of chromosome abnormalities and non-participation, data were collected on 891 consecutive patients who were registered between January and August, 1998. Data on first-cousin consanguinity and type of CHD diagnosis were collected. A z test of proportions was used to determine the association between consanguinity and subtypes of CHD. Data indicate that the proportion of first cousins in the CHD sample is higher than the proportion in the general population, supporting a hypothesis of autosomal recessive gene involvement in congenital heart disease. When subgroups of CHD were analyzed, first-cousin consanguinity was significantly associated with ventricular septal defect (VSD), atrial septal defect (ASD), atrioventricular septal defect (AVSD), pulmonary stenosis (PS), and pulmonary atresia (PA). There was no relationship between consanguinity and tetralogy of Fallot (TOF), tricuspid atresia (TA), aortic stenosis (AS), co-arctation of the aorta (CoA), and patent ductus arteriosus (PDA). Thus, in a population with a high degree of inbreeding, consanguinity may exacerbate underlying genetic risk factors, particularly in the offspring of first cousins. There may be a recessive component in the causation of some cardiac defects.

Cloning of human preprotachykinin-I promoter and the role of cyclic adenosine 5'-monophosphate response elements in its expression by IL-1 and stem cell factor

Preprotachykinin-I gene (PPT-I) encodes several peptides with organ-specific functions that link the neuroendocrine-immune-hemopoietic axis. We cloned upstream of the initiation site of human PPT-I promoter and identified consensus sequences for two cAMP response elements (CRE). PPT-I is induced by cytokines including those that signal through the cAMP pathway. Therefore, we studied the role of the two CRE in IL-1alpha and stem cell factor (SCF) stimulation of bone marrow stroma because both cytokines induce endogenous PPT-I in these cells and activate the cAMP pathway. Furthermore, bone marrow stroma expresses the transcription factors regulated by the cAMP pathways such as the repressor (ICERIIgamma) and activator (CREMtau). Mutagenesis of the two CRE and/or cotransfection with vectors that express ICERIIgamma or CREMtau indicated that the two CRE have major roles in PPT-I expression. The two CRE are also required for optimal promoter activity by SCF and IL-1alpha. A particular cytokine could concomitantly induce PPT-I and the high affinity G protein-coupled receptor for PPT-I peptides, NK-1R. We showed that SCF, a representative cytokine, induced PPT-I and NK-1R leading to autocrine and/or paracrine cell activation. Because NK-1R activates cAMP through the G protein, the results suggest that the presence of CRE sequences within PPT-I promoter could be important in the regulation of PPT-I expression by cytokines, irrespective of their ability to signal through cAMP. As PPT-I is implicated in hemopoietic regulation, immune responses, breast cancer, and other neural functions, these studies add to the basic biology of these processes and could provide targets for drug development.

[Acute phase response after stroke: differences between ischemic stroke and intracerebral hemorrhage]

BACKGROUND

To evaluate differences in the temporal profile of acute phase response (APR) between ischemic stroke (IS) and intracerebral hemorrhage (ICH).

PATIENTS AND METHOD

We studied APR parameters (< 24 h and 3-5 day) in 88 consecutive patients (43 ICH and 45 IS). The increase/decrease of the parameters between both dates was analyzed.

RESULTS

Leukocyte increase (LI) and fibrinogen increase (FI) is significantly higher in ICH than in IS (p = 0.047 and p = 0.035).

CONCLUSIONS

APR temporal profile is different for ICH and IS.

Differential expression of matrix metalloproteinases in labial salivary glands of patients with primary Sjögren's syndrome

OBJECTIVE

To determine the enzymatic activity and cellular localization of matrix metalloproteinases (MMPs) 2, 3, and 9 in labial salivary glands from patients with different degrees of severity of primary Sjogren's syndrome (primary SS).

METHODS

Gelatinase activity was determined by zymography and quantified by densitometry. The specificity of MMPs was determined using protease inhibitors and chelators, as well as activators of the latent forms of these enzymes. The cellular localization of MMPs was carried out using monoclonal antibodies that recognize their latent and active forms.

RESULTS

Labial glands from control subjects and patients showed gelatinase activity for MMP-2 and MMP-9. Activation studies revealed that both enzymes were predominantly present in their latent forms. The highest levels of MMP-9 activity were detected in patients with severe, active, primary SS (except for patients with severe clinical symptoms for extended periods) and correlated with structural and functional glandular changes. MMP-2 activity was almost the same in patients and controls. MMPs were detected by immunolocalization only in acinar and ductal cells and were homogeneously distributed throughout patients' glands. MMP-2 and MMP-9 expression paralleled their gelatinase activity. MMP-3, detectable only with immunologic methods, was absent in control subjects but abundantly expressed in patients. Importantly, MMP protein levels in acinar and ductal cells were independent of either the presence or the proximity of mononuclear infiltrate cells.

CONCLUSION

MMP-3 and MMP-9 expression, as well as MMP-9 catalytic activity, were increased in tissue samples from SS patients in a manner that correlated with the severity of the disease. Most important, increased MMP activity stemmed from exocrine epithelial cells and was not due to infiltrating lymphocytes. Thus, changes in salivary glands as a consequence of proteolysis may lead to severe glandular destruction.

[The influence of the arterial pressure in the study of cerebrovascular reactivity in carotid obstructions]

INTRODUCTION

Cerebrovascular reactivity (CVR) is the capacity of the cerebral microcirculation to increase cerebral blood flow on vasodilator stimulation. This is reduced in patients with carotid obstruction. The changes in arterial pressure produced whilst carrying out different tests for estimation of the CVR may affect its measurement by transcranial Doppler.

OBJECTIVES

To evaluate the concordance between the different methods for estimation of the CVR by transcranial Doppler in patients with carotid obstruction and to evaluate the importance of monitoring the arterial pressure during CVR tests.

PATIENTS AND METHODS

We evaluated 17 patients with internal carotid artery obstruction confirmed on arteriography. The CVR was determined by three different methods: apnea test. Breath-Holding Index (BHI) and intravenous acetazolamide test.

RESULTS

During the tests of RCV the arterial pressure was monitored. We found that there was a reduction in the average basal rate of flow and of the pulsatile index on the obstructed side, with a statistically significant association in relation to the contralateral side (p < 0.001). There was good concordance between the different tests of CVR, with reduced CVR seen on the obstructed side as compared to the contralateral side (p < 0.001) for the different tests. However, this correlation was not seen in stenosis < 70%. During the apnea test changes in blood pressure occurred, with a tendency to increase in the systolic pressure. However, there were no significant changes in blood pressure during the acetazolamide test.

CONCLUSIONS

There is good concordance in the CVR between the apnea, BHI and acetazolamide tests in carotid obstruction. Changes in arterial pressure occurred during the apnea and BHI tests. However, the acetazolamide test caused no change in arterial pressure.

Luteal progesterone relates to histological endometrial maturation in fertile women

To examine the relationship between endometrial histological maturation and reproductive hormones, we studied 11 fertile women, aged 18-37 yr. All participants had had at least 1 previous pregnancy and cycled regularly, every 25-35 days. Women collected daily, first morning voided urine for measurement of estradiol and progesterone metabolite excretion, estrone conjugates (E1c), and pregnanediol glucuronide (Pdg), respectively, throughout the cycle of study. Hormones were normalized for creatinine. Between 7-9 days after home detection of a LH surge (Sure Step), participants underwent an endometrial biopsy using a small bore (Pipelle) catheter. Tissue was prepared for histological and biochemical analyses. The histological analysis is reported herein. Endometrium was dated by 3 authors (N.S., D.H., and S.P.), all of whom were blinded to the participant's identity or timing of biopsy within her cycle. Final dating was agreed upon based upon the method of Noyes et al. E1c and Pdg were integrated throughout the cycle using the trapezoidal rule, and correlations were sought between deviation from expected histology (based upon urinary hormones and LH surge) and integrated hormone values. E1c varied over a 2-fold range in these normal women, from 1196-2040 ng/cycle. Pdg excretion was much more variable, ranging from 22-119 microg/cycle. No relationship could be found between histological lagging of endometrial maturation and lower excretion of E1c. A moderate correlation was observed (Spearman's r = 0.6; P < 0.05) between degree of histological maturation and integrated Pdg. Of two women with evidence of a disparity between gland and stromal development (glands lagging behind stroma by >2 days), one excreted 24 microg Pdg/cycle, the next to lowest value. We conclude that normal fertile women experience a wide range of hormone concentrations in the face of normal endometrial maturation. Progesterone appears to exert a dose-related effect on endometrial maturation, and the techniques we used, although relatively crude clinical measures, appeared to be sufficient to detect this relationship.

Mitral papillary fibroelastoma as a cause of cardiogenic embolic stroke: report of two cases and review of the literature

Papillary fibroelastoma (PFE) is a rare benign tumour that attaches to the endocardial surface, mostly on cardiac valves. Though usually asymptomatic, it can be the source of several complications. To date, 49 cases have been reported of embolic stroke with a PFE as the probable origin.

CASE REPORTS

(i) a 39-year-old male presented with ischemic embolic stroke; the presence of a PFE was assessed by means of transoesophageal echocardiography and confirmed by pathological findings; (ii) a 32-year-old woman presented with sudden onset of left hemiparesis; a cardiogenic embolic stroke was suspected, and a diagnosis of PFE was made based on echocardiographic and pathological findings. In both cases, surgical excision of the tumours was performed with no recurrences at follow-up. Two mechanisms can explain the formation of emboli in PFE: dislodgement of the tumour leaves or fibrin-platelet aggregation on the endocardial surface of these leaves. Transthoracic echocardiography may lead to the suspicion of a PFE, but transoesophageal echocardiography is required for confirmation. Prompt surgical excision is indicated in most cases. Anticoagulation is only recommended in situations of high surgical risk and during the wait for surgery.

[Diffusion-weighted magnetic resonance in the diagnosis of acute subcortical infarcts]

INTRODUCTION

The diagnostic efficacy of radiological studies in acute subcortical infarcts is limited by the low sensitivity of conventional computerized tomography (CT) and magnetic resonance (MR) in detecting small-sized infarcts, and the difficulty in differentiating acute from chronic lesions. Diffusion-weighted MR (DMR) has shown great sensitivity and specificity in the detection of small vessel ischemic lesions during the acute phase.

OBJECTIVE

To determine the diagnostic value of DMR in the study of patients with subcortical infarcts during the acute phase.

PATIENTS AND METHODS

We made a prospective analysis of 100 consecutive patients with a clinical diagnosis of subcortical infarct. In all cases MR examination was done within the first 10 days (average 3.9 days) following onset, using conventional and diffusion-weighted sequences.

RESULTS

In all cases the DMR showed the presence of ischemic lesions which explained, at least partly, the clinical features of the stroke. In 42 patients (42%) the DMR gave relevant information for diagnosis, as compared with the conventional MR studies, by confirming the presence of an ischemic lesion responsible for the clinical picture. The percentage rose to 50% when the examination was done within the first two days.

CONCLUSIONS

DMR gives useful information in a high percentage of patients with acute subcortical infarcts. This is due to its great sensitivity in the detection of acute lesions of small size, and capacity to distinguish acute from chronic lesions.

[Lack of correlation between plasma homocysteine levels and cerebral microangiopathy in patients wtih transient ischemic attack]

OBJECTIVE

The aim of this study is to evaluate cerebral MRI findings in patients with atherothrombotic transient ischemic attacks (TIA) and its correlation with plasma homocysteine (Hcy) levels.

PATIENTS AND METHODS

A total of 62 consecutive patients with the diagnosis of TIA of atherothrombotic origin were studied. MRI examinations were performed in all patients for the evaluation of the presence of infarct and/or white matter hyperintensities (WMHI). Plasma Hcy levels were determined according to the method described by Smolin and Schneider modified.

RESULTS

Plasma Hcy levels were significantly (p < 0.036) higher in patients with MRI-detected infarcts (9.69 +/- 2.06 mumol/l) compared with patients without infarcts (8.65 +/- 1.7 mumol/l. There was no correlation (p < 0.33) between plasma Hcy levels and the presence or absence of WMHI seen on MRI.

CONCLUSIONS

In TIA patients, plasma Hcy levels were significantly higher in patients with cerebral infarcts, but did not correlate with the presence of WMHI. Our results suggest that mild hyperhomocysteinemia would be associated with large-medium vessel rather than with small vessel disease.

[Consumption of licit and illicit drugs in Chile: results of the 1998 study and comparison with the 1994 and 1996 studies]

The principal results are presented here from the Third National Study of the Consumption of Drugs, which was carried out in Chile by the National Board for Narcotics Control between 1 September 1998 and 15 January 1999. The 1998 study used the same methodological design as the first and second studies, which were done in 1994 and 1996. The 1998 study expanded the sample to 31,665 individuals, who were representative of a population of 6,940,727 people from 12 to 64 years old, both sexes, and five socioeconomic levels and who were residents of urban areas in 62 commune administrative divisions of the 13 regions of the country. Results from the 1998 study are compared with those from 1996 and 1994. The 1998 study shows that 17.5% of Chileans have at some time in their life used one of the three illicit drugs most popular in the country: marijuana (16.8%), coca paste (2.3%), and cocaine hydrochloride (4.0%). The prevalence of use of any of the three drugs, mainly marijuana, during the preceding year was 5.3% and during the preceding month 2.2%. With respect to licit drugs, 28.4% of Chileans have at some time in their lives used antianxiety drugs, 84.4% of them have consumed alcohol, and 71.9% have used tobacco. Most of the people who once used illegal drugs have stopped doing so: 71.6% in the case of marijuana, 64.1% with coca paste, and 66.8% with cocaine hydrochloride. For legal drugs, the percentages were lower: 55.5% for anxiolytics, 16.0% for alcohol, and 34.5% for tobacco. The consumption of licit and illicit drugs was several times greater among men than among women, except for anxiolytics, whose use was three times greater among women. Drug use was more frequent among persons between 19 and 25 years old. Consumption of illegal drugs was more frequent at higher socioeconomic levels, and use of licit drugs was more common in the lower socioeconomic levels. The 50th percentile of the age of initiating drug use was 17 years for alcohol, 15 for tobacco, 30 for antianxiety agents, 17 for marijuana, 20 for coca paste, and 21 for cocaine hydrochloride. Comparing the results of the three studies shows that, after an increase in the use of licit drugs between 1994 and 1996, there was a stabilization in 1998. With illegal drugs there was a modest increase in consumption between 1996 and 1998, following a small reduction between 1994 and 1996.

'Herald hemiparesis' of basilar artery occlusion: early recognition by transcranial Doppler ultrasound

A transient hemiparesis may be ocassionally present at an early stage of the thrombosis of the basilar artery (herald hemiparesis). We report on one of these cases and the valuable role of transcranial Doppler ultrasound (TCD) to the early detection of the stroke-in-evolution. TCD in the emergency room is a good tool to assess a basilar occlusion, searching for direct (absence of signal at the basilar artery) and indirect (reversal flow of the pre-communicating segment the of posterior cerebral artery through the posterior communicating artery) signs. Early recognition and treatment of this condition could avoid the development of the full syndrome of the basilar artery thrombosis.

[Acute pseudobulbar paralysis: the use of diffusion techniques with magnetic resonance]

INTRODUCTION

Acute pseudobulbar palsy produced by bilateral cerebral infarctions is a rare syndrome, which includes among its symptoms mutism, severe dysphagia and diverse sensory-motor signs.

CLINICAL CASES

We report two middle-aged patients who suddenly developed a severe dysarthria and dysphagia, which impeded their ability to speak and to feed themselves, with spasmodic laughing and crying and slight motor deficit ('pure' pseudobulbar palsy). The acute lesions, using conventional and diffusion-weighted magnetic resonance imaging, corresponded partially to the anterior choroidal artery (case 1: acute lesion in the left periventricular white matter and a subacute one in the right semioval centrum; case 2: acute lesions in the right frontal subcortical white matter and in the periventricular white matter adjacent to the left lateral ventricle). The favorable evolution of these patients in contrast to previously described patients with acute pseudobulbar palsy could indicate that the motor deficit is a prognostic factor for this syndrome.

CONCLUSIONS

Diffusion-Weighted magnetic resonance imaging permits differentiation with high precision of the acute lesions in patients who present old ones. Sometimes multiple acute lacunar infarctions (MALI) are found to be responsible of the syndrome. Hypertension and diabetes are the risk factors for the small vessel disease underlying these MALI.

Transcriptional up-regulation of the cyclin D2 gene and acquisition of new cyclin-dependent kinase partners in human T-cell leukemia virus type 1-infected cells

Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent for adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis. Tax(1) is a 40-kDa phosphoprotein, predominantly localized in the nucleus of the host cell, which functions to transactivate both viral and cellular promoters. It seems likely that HTLV-1, through expression of the viral regulatory protein Tax(1), provides some initial alteration in cell metabolism predisposing the development of ATL. Here, we demonstrate that HTLV-1 infection in T-cell lines and patient samples causes overexpression of an early G(1) cyclin, cyclin D2. The transcriptional up-regulation of the cyclin D2 gene is due to activation of Tax on the cyclin D2 gene. More important, we find that overexpression of cyclin D2 is accompanied by acquisition of new partners such as cyclin-dependent kinase 2 (cdk2), cdk4, and cdk6 in infected cells. This is in contrast to uninfected T cells, where cyclin D2 associates only with cdk6. Functional effects of these cyclin-cdk complexes in infected cells are shown by hyperphosphorylation of Rb and histone H1, indicators of active progression into S phase as well as changes in cellular chromatin and transcription machinery. These studies link HTLV-1 infection with changes of cellular cyclin gene expression, hence providing clues to development of T-cell leukemia.

[Determination of Doppler parameters in the study of basal cerebral veins: basal vein of Rosenthal and middle cerebral vein]

INTRODUCTION

To date, little attention has been paid to the study of the venous system by means of transcranial Doppler ultrasound. The objective of our study was to learn how to localize cerebral blood flow and find the normal values of different ultrasonographic parameters.

PATIENTS AND METHODS

We studied 20 healthy persons in whom the arterial system of the circle of Willis had previously been shown to be normal. Transcranial Doppler scan was done with the person lying face upwards, using a transtemporal 2 MHz catheter. In the study we included persons in whom at least one of the two veins could be studied unilaterally.

RESULTS

We studied twelve men and eight women aged between 25 and 78 years. The basal vein of Rosenthal, localized bilaterally in 70% of the cases, was identified as a wave of low pulsation between segments P1 and P2 of the posterior cerebral artery, going away from the catheter at a speed of about 11 cm/second. The middle cerebral vein was found bilaterally in only 35% of the cases as a wave near to the middle cerebral artery but in the opposite direction, at an average velocity of approximately 11.7 cm/second and of low pulsation.

CONCLUSIONS

In spite of the technical problems, which can be solved using contrast agents, it is possible to study the cerebral venous system by means of transcranial Doppler. Our Unit is the first in Spain to show this. We therefore wish to promote the use of transcranial Doppler in cerebral venous disorders.