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Biomedical subjects

V Demarin

Publications and source records attributed to V Demarin.

At least 19 recordsLinked to original sources

Aortic arch dissection presenting with hemodynamic spectrum of aortic regurgitation on transcranial Doppler.

The diagnosis of aortic dissection is frequently missed at the time of hospital admittance. Neurological presentations are rare, and neuro-sonography is rarely used. We describe a patient with atypical clinical presentation of aortic arch dissection in whom neuro-sonological investigations showed a "cathedral like" haemodynamic spectrum of aortic regurgitation, directing the investigation towards the diagnosis.

Aortic Dissection↗

Teaching of neuroepidemiology in Europe: time for action.

Many epidemiological and clinical studies in Europe, especially in Eastern Europe and countries in transition, are of poor methodological quality because of lack of background knowledge in clinical epidemiology methods and study designs. The only way to improve the quality of epidemiological studies is to provide adequate undergraduate and/or postgraduate education for the health professionals and allied health professions. To facilitate this process, the European Federation of Neurological Societies (EFNS) Task Force on teaching of clinical epidemiology in Europe was set up in October 2000. Based on analyses of the current teaching and research activities in neuroepidemiology in Europe, this paper describes the Task Force recommendations aimed to improve these activities.

Education, Medical↗

Treatment of Alzheimer's disease with stabilized oral nicotinamide adenine dinucleotide: a randomized, double-blind study.

This study was designed to evaluate the effect of stabilized oral reduced nicotinamide adenine dinucleotide (NADH) on cognitive functioning in patients with Alzheimer's disease (AD). NADH is a coenzyme that plays a key role in cellular energy production and stimulates dopamine production. In previous trials NADH has been shown to improve cognitive functioning in patients with Parkinson's disease, depression and AD. The present trial was a randomized, placebo-controlled, matched-pairs, double-blind, 6-month clinical study. Patients with probable AD (n = 26) were randomized to receive either stabilized oral NADH (10 mg/day) or placebo. Twelve pairs of subjects were matched for age and baseline total score on the Mattis Dementia Rating Scale (MDRS) and the Mini Mental State Examination. After 6 months of treatment, subjects treated with NADH showed no evidence of progressive cognitive deterioration and had significantly higher total scores on the MDRS compared with subjects treated with placebo (p < 0.05). Analysis of MDRS subscales revealed significantly better performance by NADH subjects on measures of verbal fluency (p = 0.019), visual-constructional ability (p = 0.038) and a trend (p = 0.08) to better performance on a measure of abstract verbal reasoning. There were no differences between groups in measures of attention, memory, or in clinician ratings of dementia severity (Clinical Dementia Rating). Consistent with earlier studies, the present findings support NADH as a treatment for AD.

Administration, Oral↗

Acute stroke treatment in Europe: a questionnaire-based survey on behalf of the EFNS Task Force on acute neurological stroke care.

In 1997 the EFNS Task Force on Acute Neurological Stroke Care published its recommendations for acute stroke care (Brainin et al., 1997), which, in 1999, was followed by a stroke care inventory (Brainin et al., 2000) assessing the development of acute stroke care. In 2000 all 33 members of the EFNS Stroke Scientist Panel were asked to complete a questionnaire on the treatment of acute stroke in their country as of 2000. Data were based either on national surveys or a personal estimate of national practice, together with data from the personal practice of the panel member. Data from 22 countries were received. One of the principal findings is the lack of systematic evidence about practice in a significant number of European countries. Results illustrate that neurologists have a leading role in implementing acute stroke treatment guidelines and in adopting new therapeutic methods in most countries, but there is a wide variation in the application of different therapeutic procedures.

Advisory Committees↗

Presynaptic vesicles, exocytosis, membrane fusion and basic physical forces.

The theoretical hypothesis is presented trying to explain the vesicle release from presynaptic nerve ending and membrane fusion. This theoretical concept implies only essential physical forces such as electrostatic force and surface tension force. Transmembrane resting potential of approximately -70 to -80 mV means that the intracellular fluid is electronegative in comparison with extracellular one. In this concept it is supposed that the inner and outer lipid layer of the membrane also have different electrostatic charges. Presynaptic vesicles are made from cell membrane by endocytic process through which the vesicle loses the contact with cell membrane. Also, during the endocytic process, the inner lipid layer of the cell membrane becomes the outer lipid layer of presynaptic vesicle and vice versa. During the resting phase, equally charged lipid layers of presynaptic vesicle and cell membrane repel each other, but during the action potential, differently charged lipid layers strongly attract each other, bringing the presynaptic vesicle and cell membrane in close contact. Immediately thereafter, the surface tension forces open the pore and fuse both membranes trying to minimize the area of the contact between water fluids (extra and intracellular fluid) and lipid fluids (lipid membrane bilayer). Since only fundamental physical forces are involved in this process, it could be very fast, effective and almost inexhaustible. Similar mechanisms could be responsible for all exocytic processes and all membrane fusion processes in the cells.

Action Potentials↗

Polymorphism of apoprotein E (APOE), methylenetetrahydrofolate reductase (MTHFR) and paraoxonase (PON1) genes in patients with cerebrovascular disease.

Although controversial, data on the genetic polymorphism of apoprotein E (APOE), methylenetetrahydrofolate (MTHFR) and paraoxonase (PON1) genes implicate their role in the development of cerebrovascular disease. The aim of this study was to assess the association of polymorphism of APOE, MTHFR and PON1 genes in 56 stroke and 36 carotid stenosis patients, and in 124 control subjects by PCR-restriction fragment length polymorphism analysis. In the stroke group a significantly different MTHFR genotype distribution (p=0.004, odds ratio for T/T of 17.571), but no significant difference in APOE and PON1 allele and genotype distribution compared to the control was found. The carotid stenosis group exhibited a significantly different APOE allele and genotype distribution (p=0.023, odds ratio APOEepsilon3epsilon4 of 4.24), but no significant difference in the MTHFR and PON1 allele and genotype distribution from the control group. The preliminary results obtained in this study revealed an association of the MTHFR and APOE gene polymorphism with cerebrovascular disease, suggesting a significant risk for stroke in subjects who are homozygous for the T allele and for carotid stenosis in subjects having APOEepsilon3epsilon4 genotype. Additional studies in larger patient groups are needed to confirm these observations.

Adult↗

Carotid artery intima thickness and flow velocity after discontinuation of hormone replacement therapy in postmenopausal women: follow-up study.

AIM: To investigate the effect of discontinuation of hormone replacement therapy on the intima thickness and blood flow velocity of the common carotid artery. METHODS: The thickness of the left common carotid artery intima and maximal systolic blood velocity were measured by real-time and Doppler ultrasonography in 75 healthy postmenopausal women starting sequential combined hormone replacement therapy. The measurements were performed at the start and after 6 and 12 months of the therapy. Thirty two women decided to discontinue the therapy after 6 months, whereas 43 continued. RESULTS: In the group that continued with the hormone replacement therapy, a significant decrease was recorded in the mean baseline values for carotid artery intima thickness and flow velocity at 6 months (0.35+0.11 vs 0.54+0.19 mm and 0.73+0.16 vs 0.87+0.19 m/s, respectively, p?0.001) and 12 months of follow-up (0.36+0.1 mm and 0.72+0.15 m/s vs baseline, respectively, p?0.001). In women who discontinued the therapy, there were significant deviations from the baseline values in the intima thickness (0.36+0.11 vs. 0.59+0.09 mm, p=0.010) and flow velocity (0.75+0.14 vs. 0.85+0.16 m/s, p?0.001) at 6 but not at 12 months of the follow-up (0.55+0.12 mm, and 0.85+0.17 m/s vs baseline; p=0.148 and p=0.965, respectively). CONCLUSION: Decreased flow velocity and reduced intima thickness were directly related to blood vessel wall dilatation after estrogen component of hormone replacement therapy. Discontinuation of the hormone replacement therapy returned the flow velocity and intima thickness to their baseline values.

Aged↗

Transcranial Doppler sonography for post-traumatic stress disorder.

Transcranial Doppler sonography (TCD) was used to examine the mean speed of blood circulation in 50 patients suffering from post-traumatic stress disorder (PTSD). The sonography was repeated 6 months after successful psychiatric treatment. Doppler sonography of Willis's circle blood vessels and vertebrobasilar flow was performed on healthy controls as well. All of the subjects in both groups were 20 to 43 years old and had not suffered from other diseases. Vasospasm of Willis's circle blood vessels was discovered in 62% of PTSD patients, which decreased to 22% after treatment. In the control group, it occurred in 8% of subjects. TCD examination of vertebrobasilar system blood vessels did not identify significant differences in blood circulation mean speed between controls and PTSD patients, regardless of whether they had or had not been treated. This research proved the value of TCD in discovering Willis's circle blood vessel vasospasm in PTSD patients, which suggests the inclusion of TCD in diagnosing PTSD. The value of TCD was affirmed in controlling treatment success, because after 6 months of psychiatric treatment, there were significantly fewer patients with Willis's circle blood vessel vasospasm.

Adult↗

Transcranial Doppler in smoking relapse prevention strategy.

Nicotine dependence is a progressive, chronic, relapsing disorder. Nicotine is the principal and most potent psychopharmacologically active component of tobacco smoke. Through activation of nicotine receptors in the central nervous system, nicotine can lead to tolerance and dependence. Cessation of smoking is followed by severe pathophysiologic withdrawal and by long-term craving. TCD measurement of cerebral blood flow velocity (BFV) and nicotine dependence degree measured by Fragestrom questionnaire was analyzed in relation to smoking relapse. This study includes 47 participants (25 females and 22 males) included in Breathe Free Plan To Stop Smoking in Non Smoking School in Zagreb. 12 month following the end of treatment participants were divided in three groups: continued abstinence, interrupted abstinence and non abstinence. High nicotine dependence combined with TCD pathological finding significantly discriminated successes and failures, suggesting that smokers with pathological TCD need specific therapeutic approach with more social support, individualized coping skills and cognitive restructuring. Measuring cerebral flow velocity by transcranial Doppler in smokers showed the practical validity in prediction of smoking relapse.

Adaptation, Psychological↗

Vertebral artery hypoplasia--sex-specific frequencies in 36 parent-offspring pairs.

The major interest in vertebral artery (VA) hypoplasia comes from its possible connection to migraines with aura as well as from the fact that it is one of the risk factors for a stroke. Therefore, the aim of this preliminary study was to investigate the mode of inheritance of VA hypoplasia. Initially, color Doppler of VA was performed in 64 first- and second-degree relatives of 33 probands, and the presence of VA hypoplasia was confirmed according to the already established criteria. Since a higher prevalence of VA hypoplasia (15.6%) in probands'relatives in comparison with 2.34% in the general population of Croatia was indicative of a strong familial predisposition for this condition, an analysis of family data by means of Pearson's chi-square statistics has been performed. In this analysis, the observed sex-specific frequencies of 36 parent-offspring pairs composed only of affected parent and his/her (affected or non-affected) offspring are compared to the frequencies as expected under eight proposed models. For both--autosomal and X-linked monogenetic inheritance--four hypotheses have been chosen, assuming that the individuals having the affected allele (in combination with a healthy one) have 100%, 50%, 40% and 0% chances of developing VA hypoplasia. Out of eight tested models only two--completely dominant and completely recessive X-linked models--were rejected. But, from the six non-rejected models, goodness-of-fit statistics showed that the hypothesis of X-linked inheritance of VA hypoplasia with the "healthy" allele being stronger (60% effect on phenotype)--almost perfectly fit the data (chi2 = 2.0023; df = 7; p = 0.9597). Further research encompassing a more enlarged family sample is needed to confirm the present findings.

Female↗

Acute neurological stroke care in Europe: results of the European Stroke Care Inventory.

Following the 1997 Recommendations of the EFNS Task Force on Acute Neurological Stroke Care (European Journal of Neurology, 1997: 4:435-441) a European Inventory was undertaken to assess the development of acute stroke care in the EFNS member countries and to give an estimate of the needs based on 1997 data. All 30 members of the EFNS Stroke Scientist Panel were asked to complete a questionnaire on acute stroke epidemiology as well as acute stroke care in their country. Data were based either on national surveys, hospital statistics, or estimates given on the basis of extrapolation of regional studies, or other defined sources. Specialist estimates were also taken into account where no other data source was available. Data from 22 countries were received and referred to almost one million strokes occurring per year in a population of over 500 million. Most epidemiological data confirmed an east-west gap known from previous studies. These included rates that, in eastern countries, were higher for incidence, stroke as a leading cause of death, and 30-day case-fatality, and rates that were lower for overall hospitalization or availability of CT scanning. East-west differences were not seen for the total number of acute stroke units or the number of acute stroke units set up within neurological hospital departments, nor for most other quality indicators of acute stroke care with the exception of technological standards in some countries. The higher rates for 30-day case-fatality in eastern Europe (mostly above 20%) compared with western Europe (mostly below 20%) are probably caused by a case mix with more severe ischemic strokes and a higher percentage of cerebral haemorrhages admitted for acute care in eastern Europe. This is probably due to the higher prevalence of the most common risk factors for stroke in these countries which tend to result in more severe strokes. This, therefore, underlines the need for stroke prevention programmes especially in eastern Europe. This epidemiological east-west gap is not reflected by most quality indicators for acute stroke care, e.g. total number of acute stroke units available within each country. Most eastern European countries have a well-developed neurological care system for acute stroke but still have urgent technological and socioeconomical needs. The leading role of clinical neurology in acute stroke care is visible in most but not all European countries.

Aged↗

Haemodynamic changes in patients with whiplash injury measured by transcranial Doppler sonography (TCD).

The daily increasing number of cervical whiplash injuries presents ever-greater requirement for vertebrobasilar diagnostics. A cervical spine injury, which is quite frequent injury, may occur during a fall, or industrial, traffic, sport or war injury. Transcranial Doppler (TCD) sonography with Transcan 3-D EME device and 2 MHz probe was used for the assessment of vertebrobasilar circulation in patients with a whiplash injury of the cervical spine, that occurred mostly in car accident. This study includes 47 patients with clinically verified cervical spine trauma with x-ray evidence of no bone lesion. The patients were examined by TCD within a month, and then six months following the accident. The obtained values were compared to normal blood flow velocities and correlated with the severity of clinical picture. During the first month after the injury, statistically significant disturbances in the vertebrobasilar circulation were recorded, such as the increase in mean blood flow velocities in AVL (68%), AVR (62%) and BA (51%) (mostly as spasam). Six months later, normal findings were obtained in about 50% of the vessels, whereas in rest of the patients vasospasam persisted in one, two or all examined blood vessels. TCD of the vertebrobasilar circulation was found to be a very useful method in the diagnostics and follow-up of patients with a whiplash injury.

Adult↗

Value of color-Doppler imaging in diagnosis of intrabulbar and intraorbital tumors.

Patients with intrabulbar and intraorbital tumours have been investigated by colour Doppler imaging. In the first group there were 20 patients with malignant melanoma of the uvea and in the second group there were 19 patients with cavernous hemangioma. The third group was a control group represented by 20 healthy individuals. In the group of patients with uveal melanoma it has been established that every patient, except one, has a blood flow inside of tumour tissue. Internal blood flow of intraorbital hemangioma was slower than inside the melanoma and the resistance index was lower. Comparison of blood flow in all patients has shown that there is no statistically significant difference between ophthalmic artery, central retinal artery and posterior ciliary arteries except in maximal blood flow in central retinal artery and posterior ciliary arteries.

Blood Flow Velocity↗

Color Doppler flow imaging (CDFI) of the vertebral arteries--the normal appearance, normal values and the proposal for the standards.

In order to assess mean diameters and blood flow velocities (BFV), Color Doppler Flow Imaging (CDFI) of vertebral arteries (VA) was performed. Five hundred and ninety six persons without carotid disease or symptoms related to vertebrobasilar system were analyzed by CDFI of VA. Mean right VA diameter was 3.37 +/- 0.6 mm and left 3.55 +/- 0.61 mm. Women had thinner VA (p < 0.05). Left VA was wider (p < 0.05). Mean right BFV was 48.31 +/- 14.09 cm/s and left 48.93 +/- 13.94 cm/s. Females had higher BFV (p < 0.05). BFV didn't very with age (p > 0.05). The VA hypoplasia was present in 2.34%, asymmetry in 15% (left VA dominant in 64%). Visualisation of V1 and V2 segment was possible in 100% and of the origin in 81.7% on the right, and 80.7% on the left side. CDFI is a reliable method for evaluation of VA. Left VA was wider. Women had thinner VA. Hypoplasia was present in 2.34% and asymmetry in 15%.

Adolescent↗

Influence of prolonged stress on risk factors for cerebrovascular disease.

The main purpose of this study was to analyze the influence of psychological and socio-economic factors on the frequency and characteristics of risk factors for cerebrovascular disease (CVD) among Croatians. A group of 120 war sufferers with signs of post-traumatic stress disorder and adaptation disturbances have been studied, and compared with a control group of 120 persons with no traumatic war experience. The risk factors for CVD were registered using epidemiological, clinical and functional measures, and level of the risk. In a displaced persons group a significant higher rates (p < 0.05) of arterial hypertension (AH), hyperlipidemia and obesity are found, with particularly higher rates of occurrence of AH and hyperlipidemia in younger individuals. Alcoholism was more frequent in the control group. Total risk for stroke was higher in the exposed group. The authors conclude that there is a need for undertaking intensive preventive measures in the risk population exposed to chronic stress and negative socioeconomic life conditions.

Adult↗