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Biomedical subjects

A Pines

Publications and source records attributed to A Pines.

At least 37 records · Page 2Linked to original sources
PubMed2001

Retrograde embolism and atherosclerosis development in the human thoracic aorta: are the fluid dynamics explanations valid?

The mechanisms of atherosclerosis development in the thoracic aorta is miscellaneous and still only partially understood. The marked variability of the sites of deposition of atherosclerotic plaques in the aorta could not be clarified based solely on the risk-factors theory of atherosclerosis. The sites of deposition of atherosclerotic plaques are considered to be affected by blood-flow patterns that cause areas of altered shear stress on the aortic wall. Close relations between protruding aortic plaques (PAP), stroke and peripheral emboli were established. The analysis of PAP distribution and motion to characterize atherogenesis in the human thoracic aorta and the pathogeneses of embolic events was performed. We concluded that protruding aortic plaques and markers of relative aortic flow instability (occurrences of vortices) are predominantly noticed in the human arch and in the descending aorta, whereas the ascending aorta showed lesser prevalence of atheromatosis. Reversal and rotational blood-flow in the thoracic aorta most likely exist in all patients with systemic emboli and mobile protruding aortic atheromas. Therefore, retrograde cerebral embolism from distal aortic plaques is conceivable.

Adolescent↗
PubMed2001

Hypertension in menopausal women--a special case, for special treatment?

After the menopause the consequences of hypertension in women change. Their risks of myocardial infarction and stroke rise steeply, a rise that has been blamed in part on the loss of estrogen and the onset of menopausal metabolic syndrome, with endothelial dysfunction, hyperlipidemia, insulin resistance and derangement in coagulation. Hypertensive menopausal women have not had optimum treatment. They have poorer prognoses than men of the same age. Their antihypertensive management therefore merits special attention. Hormone replacement, aspirin prophylaxis and lipid-lowering drugs have their place. The antihypertensive drug chosen should not worsen the metabolic syndrome: angiotensin-II converting enzyme (ACE) inhibitors are therefore among the first-line drugs. Few drugs have been specifically aimed at menopausal hypertension and these are reviewed here.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

The combined cough frequency/severity scoring: a new approach to cough evaluation in clinical settings.

Cough assessment is an important component in the clinical evaluation of patients with respiratory and cardiovascular disorders (asthma, chronic obstructive lung disease, congestive heart failure, etc.). A dry bothersome cough is the most common adverse class effect of all angiotensin-converting enzyme inhibitors (ACE-I). The present study was aimed to determine the feasibility of a new combined frequency/severity cough scoring method in patients with ACE-I induced cough before and after their modification with aspirin addition. The study was designed to compare two different regimens of active treatment: intermediate (500 mg) versus low (100 mg) dose aspirin in ACE-I cough suppression (self-matched control data) and comprised 21 patients (14 men, 7 women; mean age 62 +/- 11 years) on ACE-I treatment. ACE-I treatment was discontinued and the dry cough completely disappeared, but returned in all patients within one week (rechallenge period) after ACE-I reintroducing. Severity of cough was defined as follows: 0--no cough at all; 1--occasional hems; 2--mild, isolated cough, without additional symptoms; 3--moderate, paroxysmal cough, without additional symptoms; 4--severe, strenuous cough, accompanied by chest discomfort. In addition to cough severity score, cough frequency score (0-10) was obtained using a visual analog scale: 0 = I never cough; 10 = I cough all day. Low doses of aspirin were ineffective to suppress ACE-I induced cough. In contrast, intermediate doses completely abolished cough in 14 patients and reduced coughing in all but one patient. Cough severity and cough frequency scores decreased, respectively, from 2.6 +/- 1.1 to 0.7 +/- 1.0 (p<0.001) and from 6.9 +/- 2.2 to 2.1 +/- 2.4 (p<0.0001). Overall, the cough frequency score method alone could identify a beneficial modification of cough in 17 (81%) patients and cough severity score method alone in 17 (76%). Using the combined cough frequency/severity scoring, a beneficial modification of cough could be identified in 20 (95%) of patients. The new combined cough frequency/severity scoring is suitable for clinical practice and can improve the identification of dynamic cough modifications during treatment period as compared with the conventional frequency score method. It may have important implications in the evaluation of patients with respiratory and cardiovascular disorders.

Aged↗
PubMed2000

The effect of oophorectomy and estrogen replacement therapy on Doppler derived parameters of aortic flow.

OBJECTIVES: The immediate consequences of surgical castration and estrogen replacement therapy (ERT) on left ventricular systolic performance as assessed by Doppler-derived parameters of aortic flow were examined. METHODS: A follow up study comprising two groups: eight premenopausal women who underwent hysterectomy and bilateral oophorectomy and started ERT 1 week after surgery - the study group, and a control group consisted of eight premenopausal women who did not start ERT following hysterectomy. Doppler echocardiography was performed before surgery, 1 week and 1 month post surgery. RESULTS: In both groups significant increase in heart rate was observed after 1 week, remaining high after 1 month in the control group only. The early post-operative period in all women was characterized by an increase in aortic flow velocity, but was statistically significant in the study group only. After initiation of ERT a significant decrease in peak flow velocity (PFV) and mean acceleration (MA) was recorded. CONCLUSIONS: Changes in estradiol level may be associated with alterations in left ventricular function. The initial and acute effect of estrogen on the heart muscle after surgical castration is towards a decrease in Doppler-derived parameters of aortic flow. Whether these effects represent a depression of left ventricular function, or alternatively, reflect peripheral vasculature reactivity, requires further evaluation.

Adult↗
PubMed2000

Evidence of nonspecific surface interactions between laser-polarized xenon and myoglobin in solution.

The high sensitivity of the magnetic resonance properties of xenon to its local chemical environment and the large (129)Xe NMR signals attainable through optical pumping have motivated the use of xenon as a probe of macromolecular structure and dynamics. In the present work, we report evidence for nonspecific interactions between xenon and the exterior of myoglobin in aqueous solution, in addition to a previously reported internal binding interaction. (129)Xe chemical shift measurements in denatured myoglobin solutions and under native conditions with varying xenon concentrations confirm the presence of nonspecific interactions. Titration data are modeled quantitatively with treatment of the nonspecific interactions as weak binding sites. Using laser-polarized xenon to measure (129)Xe spin-lattice relaxation times (T(1)), we observed a shorter T(1) in the presence of 1 mM denatured apomyoglobin in 6 M deuterated urea (T(1) = 59 +/- 1 s) compared with that in 6 M deuterated urea alone (T(1) = 291 +/- 2 s), suggesting that nonspecific xenon-protein interactions can enhance (129)Xe relaxation. An even shorter T(1) was measured in 1 mM apomyoglobin in D(2)O (T(1) = 15 +/- 0.3 s), compared with that in D(2)O alone (T(1) = 506 +/- 5 s). This difference in relaxation efficiency likely results from couplings between laser-polarized xenon and protons in the binding cavity of apomyoglobin that may permit the transfer of polarization between these nuclei via the nuclear Overhauser effect.

Animals↗
PubMed2000

A Porous Crystalline Molecular Solid Explored by Hyperpolarized Xenon We thank the Italian Ministry of Universities and Scientific Research (PRIN program) for financial support. The research with laser-polarized xenon was supported by the Director, Office of Energy Research, Office of Basic Energy Science, Materials Sciences Division of the U.S. Department of Energy. T.M. thanks the Alexander von Humboldt Foundation for a Feodor Lynen Fellowship.

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Journal Article↗
PubMed2000

Gender paradox in cardiac calcium deposits in middle-aged and elderly patients: mitral annular and coronary calcifications interrelationship.

OBJECTIVES: mitral annular calcification (MAC) occurs mainly in middle-aged and elderly patients and can lead to serious clinical consequences. Male predominance in the prevalence of coronary disease is well-established. Paradoxically, the prevalence of MAC, which is theoretically based on the same etiological mechanisms as coronary atherosclerosis, seems to be predominant in postmenopausal women. The goal of this work was to investigate gender influences on interrelationship between MAC and coronary calcifications (CC) in the same population of middle-aged and elderly patients with increased cardiovascular risk. METHODS: the study comprised 522 patients (284 men and 238 postmenopausal women, aged 52-80 years, mean 65+/-6), who were recruited to the International Nifedipine GITS Study of Intervention as a Goal in Hypertension Treatment (INSIGHT) study in our region. They underwent both fast spiral computed tomography of the heart and echo-Doppler. MAC was defined as advanced when its thickness was > or =5mm; otherwise it was defined as trivial. RESULTS: there were 37 (16%) women and 25 (9%) men with advanced MAC (AMAC), 97 (41%) women and 118 (42%) men with trivial MAC and 104 (44%) women and 141 (50%) men without MAC. The prevalence of any type of CC was significantly higher among men (P=0. 001). In sharp contrast to the distinct male predominance in coronary disease, AMAC was more prevalent among women. In patients without CC prevalence was 9 and 4%, increasing to 16 and 8% in those with nonsevere CC and to 38 and 14% in patients with severe CC, respectively (P=0.001). Multivariate analysis showed that AMAC can predict the presence of severe CC in women and men, with OR of 4.1 and 2.6 (CI 1.2-14.8 and 1.0-10.6) and coronary disease with OR of 2. 5 and 2.5 (CI 0.6-10.6 and 1.0-6.4), respectively. CONCLUSIONS: AMAC signifies a high probability of coronary atherosclerosis in patients of both genders. The inverted gender predominance in the prevalence of annular calcification and CC could be explained by additional etiological (likely osteoporotic) mechanisms of MAC development among postmenopausal women.

Aged↗
PubMed2000

Visualization of gas flow and diffusion in porous media.

The transport of gases in porous materials is a crucial component of many important processes in science and technology. In the present work, we demonstrate how magnetic resonance microscopy with continuous flow laser-polarized noble gases makes it possible to "light up" and thereby visualize, with unprecedented sensitivity and resolution, the dynamics of gases in samples of silica aerogels and zeolite molecular sieve particles. The "polarization-weighted" images of gas transport in aerogel fragments are correlated to the diffusion coefficient of xenon obtained from NMR pulsed-field gradient experiments. The technique provides a unique means of studying the combined effects of flow and diffusion in systems with macroscopic dimensions and microscopic internal pore structure.

Diffusion↗
PubMed2000

Attitudes towards hormone replacement therapy among middle-aged women and men.

OBJECTIVES: To survey the attitudes of middle-aged women and men towards HRT and associated issues. Men were included because of the possible influence of their attitudes on womens decisions to use HRT. METHODS: Two-hundred women and 311 men, (not wife and husbands), between 45 and 55 years of age, from a general population sample, were queried about their attitudes towards menopause and HRT and on their knowledge about side effects of HRT. RESULTS: The men had a more negative attitude towards HRT than the women. Two-thirds of the subjects, mostly women, considered menopause to be a medical issue and not a developmental stage in the life cycle. The most mentioned benefits of HRT were the prevention of osteoporosis and cardiopathy, and the disadvantages were "cancer" and "side effects". The concept of menopause as a medical entity was significantly correlated with a positive attitude towards HRT and whether the responder currently used HRT. CONCLUSIONS: The attitudes of most women and men towards menopause and its psycho-social meaning play a vital role in the decision of whether women should start HRT. Education on HRT should be extended to include men who seem to have a more negative attitude towards HRT and are less informed about its benefits. Our results indicate that a positive attitude to HRT is associated with factual knowledge about its benefits and disadvantages, while a negative attitude is based more on emotional arguments.

Attitude↗
PubMed2000

Long-term mortality rates reflect progressive prognostic benefits of thrombolysis in patients with first acute myocardial infarction.

This community nonrandomized study comprised a consecutive cohort of 1,545 (81% males) < or = 65-year-old patients who survived a first acute myocardial infarction (AMI). The all-cause 4- to 5-year mortality rate was 9% (80% cardiac). Univariate analysis revealed that older age, female gender, hypertension, diabetes, not undergoing thrombolysis, higher Killip class, preinfarction heart disease, peripheral vascular disease (PVD) and chronic obstructive lung disease (COLD) were significantly associated with increased mortality. Multivariate analyses disclosed the latter five parameters as being independent predictors of mortality. Our results show that patients undergoing thrombolysis enjoyed a progressive prognostic benefit over time. The independent contribution of PVD and COLD to long-term mortality is highlighted, in addition to the contribution of thrombolytic therapy, Killip class, and heart disease prior to infarction as being important predictors of long-term mortality in patients with a first AMI.

Female↗
PubMed2000

Fluid dynamics and atherosclerosis development in the human thoracic aorta: a transesophageal echocardiographic evaluation of protruding aortic plaque distribution and motion.

The pathogeneses of atherosclerosis in the thoracic aorta is heterogeneous and still incompletely elucidated. Protruding aortic plaques (PAP), reliable markers of atherosclerosis development and extension, could be easily identified by transesophageal echocardiography (TEE). A close relation between atherosclerosis development in the thoracic aorta, stroke and peripheral emboli were established. The purpose of this study was to use PAP distribution and motion on TEE to characterize atherogenesis in the human thoracic aorta. Out of 569 consecutive patients (age range 18-83 years), 108 were referred for TEE to evaluate recent embolism (Group I). The remaining 461 patients were referred for TEE for reasons unrelated to embolism (Group II). The plaque thickness was measured perpendicularly to the aortic wall. In the subgroup of patients with multiple mobile lesions, multiple vortices were suggested to be present when simultaneous rotations in different directions were found. The presence of a fixed PAP was associated with a statistically significant, albeit moderate, increase in the risk for embolism (adjusted odds ratio 4.1). The presence of mobile lesions was linked to an abrupt augmentation in this risk (adjusted odds ratio 30.1). Among the 35 patients in Group I there were 69 PAP: 8 (12%) in the ascending, 28 (41%) in the arch and 33 (48%) in the descending aorta. A total of 34 mobile lesions was detected: 1 (one patient) in the ascending aorta, 15 (10 patients) in the arch and 18 (11 patients) in the descending aorta. There was no significant difference between the arch and the descending aorta regarding the frequency of the plaques in these regions, whereas the ascending aorta presented the lowest prevalence for atheromatosis. Diastolic retrograde and rotational flows were observed in all patients. There were 16 multiple mobile PAP in 6 patients: in all these cases simultaneous rotations of mobile aortic plaques (MAP) in different directions (highly suggestive for the presence of multiple vortices and significant flow instability) were found in the arch and the descending but not the ascending aorta. Protruding aortic plaques and signs of relative aortic flow instability (presence of vortices) are mainly observed in the human arch and in the descending aorta, whereas the ascending aorta presented the lowest prevalence for atheromatosis. This issue may have significant implications in the study of atherosclerosis development in the human thoracic aorta and the pathogeneses of embolic events.

Adolescent↗
PubMed2000

Emergency room referral to internal medicine wards or to coronary care units of patients with first acute myocardial infarction. Israel Study Group on First Acute Myocardial Infarction.

The objective of the study was to assess factors associated with ward assignment in the emergency room for patients < or = 65 years old with first acute myocardial infarction. We analysed uni- and multivariate predictors for ward assignment (coronary care unit versus internal ward). Eight major centrally located Israeli hospitals provided data during one year. The study population included 1252 patients, of whom 83% were men, 37% were hypertensives, 22% were diabetics, and 14% had previous anginal syndrome. Most patients (83%) were admitted to the coronary care unit. Internal medicine ward assignment was significantly associated with advanced age, history of hypertension or diabetes, a longer time from appearance of symptoms to arrival at the hospital, and myocardial infarction type (non-Q-wave or non-anterior). The likelihood of medical ward referral increased stepwise with the increasing number of a patient's predictive factors: those with > or = 4 factors had a > 30% chance of being assigned to a medical ward compared to a < 10% chance when there were 0-3 risk factors. Exclusion of patients with thrombolysis had no effect on the results. The shortage of cardiac care unit beds apparently leads to emergency room selection acting in detriment of patients with poorest prognoses. Clear guidelines for decision making in the emergency room are needed to resolve this paradoxical situation.

Coronary Care Units↗
PubMed2000

The impact of myocardial viability as determined by rest-redistribution 201Tl single photon emission CT imaging and the choice of therapy on prognosis in patients with left ventricular dysfunction.

While thallium-201 (201Tl) single-photon emission CT (TSPECT) scintigraphy is a commonly used method for determining the viability of the myocardium, its value for predicting outcome is limited. The diagnosis of myocardial viability in patients with ischemic systolic left ventricular dysfunction might indicate which of them will benefit more from surgical revascularization. Forty patients (mean +/- SD aged 64.5 +/- 12 years, 33 males and 7 females) with impaired systolic left ventricular function (ejection fraction < or = 45%) underwent TSPECT examination. Twenty patients were surgically revascularized and 20 were treated medically. The patients were followed-up for a 34 +/- 10-month period and the cardiac long-term prognosis was evaluated. The significant viability percentage (SVP), defined as the percentage of the total number of segments showing a normal uptake of 201Tl redistribution divided by the total number of segments evaluated, was > or =55: this was observed in 18 patients. Among them, the cardiac event-free survival was 100% in the surgical group versus 22% in the medical group. However, in patients with non-SVP, the survival was lower and not significantly different in the two treatment groups. Surgical revascularization is the preferred method of treatment in patients with ischemic systolic left ventricular dysfunction and myocardial viability as defined by TSPECT scintigraphy.

Aged↗
PubMed1999

The acute effects of sublingual estradiol on left ventricular diastolic function in normotensive and hypertensive postmenopausal women.

AIM: limited information is available on estrogen influences on diastole. We aimed to investigate the acute effects of a single dose of sublingual 17beta-estradiol on left ventricular diastolic function in postmenopausal women. METHODS: the study included 28 women aged 55.6 +/- 6 (15 normotensive and 13 hypertensive), who underwent Doppler echocardiography and estradiol plasma levels determination before and 60 min after sublingual administration of 4 mg of 17beta-estradiol. RESULTS: there were no modifications in heart rate. Both systolic and diastolic blood pressure dropped significantly in the hypertensives and remained unchanged in normotensives. Estradiol levels were 1790 +/- 869 pg/ml in the normotensives and 2664 +/- 1490 in the hypertensives (P < 0.05). Peak early velocity, in the population as a whole, increased from 84 +/- 18 to 91 +/- 18 cm/s and the early-to-atrial velocity ratio from 1.1 +/- 0.4 to 1.4 +/- 0.6 (P < 0.0001 for both). Both acceleration and deceleration rates increased significantly (P < 0.0001). These changes were shared by all the patients. In addition, the hypertensive patients, who presented a baseline pattern characterized mainly by a grossly increased peak atrial velocity with reduction in the early-to-atrial velocity ratio, demonstrated a decrease in peak atrial velocity from 92 +/- 12 to 78 +/- 10 cm/s (P < 0.0001), associated with significant reductions in deceleration time (P < 0.0001) and pressure half time (P < 0.005). Therefore, the typical picture of impaired ventricular relaxation was favorably changed after estradiol administration. CONCLUSIONS: the sublingual administration of estradiol induces acute modifications in left ventricular diastolic function in postmenopausal women, with improvement in the age-related left ventricular relaxation pattern, and that these beneficial changes are more pronounced in hypertensive that in normotensive women.

Administration, Sublingual↗
PubMed1999

The acute effects of sublingual 17beta-estradiol on the cardiovascular system.

The beneficial effects of estrogen in postmenopausal women have been well documented. Cardioprotection by estrogen, which is probably the result of several metabolic alterations, appears after 2 or more years of constant use. However, acute administration of estrogen (intravenous or intracoronary) was found to improve cardiac hemodynamics and function through various non-genomic mechanisms. This article reviews data on the consequences of sublingual administration of estrogen, a non-invasive and simple dosing route which is associated with rapid absorption and prompt cardiovascular reactions. It appears that sublingual estradiol at 1 or 2 mg may improve ischemia and exercise performance in women with coronary artery disease, and augment the aortic and brachial blood flow as a result of vasodilation, whereas larger doses (4 mg) may lead to a decrease in myocardial contractility and aortic blood flow, and a slight drop in blood pressure. More data are needed to evaluate the actual clinical significance of sublingual estradiol in healthy women, in situations when endothelial dysfunction is anticipated (diabetes, hypertension) and in women with diagnosed coronary artery disease.

Absorption↗