Search PubMed⌕ Search

Biomedical subjects

A Simon

Publications and source records attributed to A Simon.

At least 343 records · Page 19Linked to original sources
PubMed1991

Is awareness of bodily change in emotion related to awareness of other bodily processes?

To what extent is reported attentiveness to bodily responses in emotion predicted by a general disposition to be attentive to one's normal, nonemotive bodily processes? University undergraduates (373 women and 167 men) completed the modified Autonomic Perception Questionnaire (APQ-R; Mandler, Mandler, & Uviller, 1958; Shields, 1984) for one of two target emotions, anger and transient anxiety, and the Body Awareness Questionnaire (BAQ; Shields, Mallory, & Simon, 1989), a measure of attentiveness to nonemotive bodily processes. In addition, the Body subscale, part of a Love Symptom Checklist concerning symptoms of romantic love was completed by 246 of these subjects. We predicted that the two measures of attentiveness to bodily response in emotion would be more strongly related to each other than to the BAQ. Significant low positive correlations between APQ-R and BAQ scores were obtained for each sex for both anger and anxiety. Correlations between the Body subscale and the APQ-R were high, positive, and significant, but correlations with the BAQ were near zero. Hierarchical multiple regression analyses showed that of the three variables entered (subject sex, Body subscale scores, and BAQ scores), the greatest change in explained APQ-R variance was accounted for by the Body subscale scores. This pattern of results was replicated in a second study of 56 women and 42 men. Results are discussed with reference to detected arousal in emotion and beliefs about emotion symptoms.

Adult↗
PubMed1991

Hypercholesterolemia modulates the effects of nitrendipine on blood pressure and platelet function in essential hypertension.

Both marked hypercholesterolemia and severe hypertension have been reported to be associated with an enhanced sensitivity of blood platelets to activating agents. To investigate a possible mutual synergistic effect of moderate hypercholesterolemia and mild hypertension on platelet reactivity, we studied in 29 patients the response to aggregating agents, ADP and collagen, and the intracellular cyclic AMP content and cytosolic Ca2+ concentration that participate, respectively, as inhibitory and stimulatory mediators in platelet responses. When compared to age- and blood pressure-matched patients with normal or slightly elevated plasma cholesterol, the patients with total platelet cholesterol higher than 6.4 mM were characterized by a decreased response to collagen and ADP (14.5 +/- 3.0 vs. 23.8 +/- 2.0 a.u. and 17.7 +/- 4.5 vs. 26.9 +/- 2.7 a.u., respectively), a tendency to a reduced cAMP content both in the basal state and after phosphodiesterase inhibition by Ro-15 2041 (2.83 +/- 0.18 vs. 3.26 +/- 0.22 mumol/10(8) cells and 4.57 +/- 0.29 vs. 5.38 +/- 0.36 mumol/10(8) cells, respectively), and no change in cytosolic Ca2+ concentration (190 +/- 11 vs. 203 +/- 13 nM). After a chronic treatment with nitrendipine (20 mg/day for 6 months), blood pressure, platelet [Ca2+]i and cAMP content decreased in the patients with normal or moderately elevated hypercholesterolemia (p less than 0.001, less than 0.001, and less than 0.05, respectively), but these effects were attenuated or absent in the patients with higher hypercholesterolemia. Plasma lipids and the platelet-aggregating response to ADP and collagen were unchanged by this long-term nitrendipine treatment in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1991

[Intrinsic (isobaric) effect of essential hypertension on visco-elastic properties of the brachial artery].

The purpose of this study was to estimate the effect of hypertension on the visco-elastic properties of the brachial artery in man. Seventy-five subjects including 23 with normal blood pressure (group N, PN = 95 +/- 7 mmHg, P designates the arterial mean pressure, P = DBP + (SBP-DBP)/3) and 52 with essential hypertension (group H, PH = 122 +/- 12 mmHg) participated to this study. We measured the diameter of the brachial artery (D) by the pulsed Doppler method, the brachial-radial pulse wave velocity (PWV) by the mecanographic method, and calculated the arterial compliance (C) by the Bramwell-Hill formula. A nonlinear model was used to calculate compliance and pression at any given pressure, in particular at PN or PH. We obtained the following results: [table; see text] Passive (pressure-induced) effect was obtained by comparing D(PH) to D(PN) and C(PH) to C(PN). Isobaric effect of hypertension was estimated by comparing D(PH) and C(PN) between the N and H groups. We concluded that hypertension actually induces a decrease in compliance. However, arterial diameter is increased in hypertension. The increase in diameter appears as a compensatory effect, without which the reduction in compliance would be more nocive to the circulatory system.

Adult↗
PubMed1991

[Increase of erythrocyte disaggregation shear rate in arterial hypertension].

Aggregation index and critical disaggregation shear rate (which represent the minimum shear rate necessary to break up the aggregates) have been measured for 21 hypertensive and 17 normotensive subjects by a laser technique (erythro-aggregameter SEFAM). A simultaneous measurement of blood viscosity by a Couette viscometer with coaxial cylinders at different shear rate allowed the calculation of critical disaggregation shear stress by the product of critical disaggregation shear rate and blood viscosity. The comparison of the results of normotensive and hypertensive subjects showed a higher aggregation index (22%, p less than 0.0001), critical disaggregation shear rate (19%, p less than 0.002) and critical disaggregation shear stress (29%, p less than 0.004) in hypertensive patients. These alterations might play an important role on development of cardiovascular complication in hypertensive subjects.

Adult↗
PubMed1991

[Comparison of isobaric effects of hypertension and diabetes mellitus on geometric and elastic properties of human arteries].

Hypertensive and diabetic mellitus diseases are known to increase stiffness of the arterial wall. However these alterations probably involve different mechanisms. To this end, we compared the effect of hypertension and diabetes on large artery caliber and elasticity at real pressure conditions and at the same level of pressure. Nine poorly controlled non insulino-dependent diabetic men without hypertension and 9 non-diabetic essential hypertensive men underwent measures of lumen diameter (pulsed Doppler) and segmental compliance (Bramwell and Hill formula; pulse wave velocity) at the brachial artery. Isobaric diameter and compliance were deduced from a non linear model, comparing diameter and pressure on one part, and compliance and pressure on the other. Pulse wave velocity was similarly increased in both diseases (11.5 +/- 1 vs 12.8 +/- 1 m/s; NS; respectively in diabetes and hypertension). Both measured and isobaric diameters were smaller in diabetic patients (4.05 +/- 0.2 vs 5.03 +/- 0.2 mm, p less than 0.1% for the measured diameters respectively in diabetes and hypertension and 4.06 +/- 0.2 vs 5.01 +/- 0.2 mm, p less than 1% for isobaric diameters). The measured and isobaric compliances were not significantly different (2.38 +/- 0.4 vs 2.08 +/- 0.2 cm/mmHg10(-4), NS, for the measured compliance respectively in diabetes and hypertension; 2.28 +/- 0.4 vs 2.4 +/- 0.2, NS for the isobaric compliance). After correction of the effect of mechanical arterial stretch induced by the different blood pressure level of the two groups, significant reduction of diameter in diabetic subjects persisted and isobaric and measured compliances remained unchanged between groups.

Adult↗
PubMed1991

The correlation between sperm cell morphology and fertilization after zona pellucida slitting in subfertile males.

OBJECTIVE: This work was undertaken to evaluate the correlation between sperm cell morphology and fertilization after zona pellucida slitting in subfertile males. DESIGN: Twenty-two couples who failed at least one in vitro fertilization attempt because of lack of oocytes fertilization underwent a zona-slitting micromanipulative procedure. A total of 245 oocytes were retrieved and inseminated by three different modes: 151 oocytes underwent micromanipulation, 2 were damaged, and the remaining 149 inseminated by the husband's sperm (group A). Fifty-five oocytes were not manipulated and inseminated by the husband's sperm (group B), and 39 oocytes were not manipulated and inseminated by a donor sperm (group C). RESULTS: Fertilization rates were 26.8%, 5.5%, and 53.8% in groups A, B, and C, respectively, and differed significantly between group A and group B. The cleavage rates were lower for oocytes fertilized by the husband's sperm (48.6%) than that obtained by donor (90%), suggesting a sperm factor contributing to this phenomenon. The procedure was most efficient in patients with a total motile sperm count after preparation of greater than or equal to 5 million and with either normal sperm morphology or defects localized to the acrosome or tail region only. Sperm with nuclear morphological abnormalities demonstrated a marked reduction in fertilization potential. CONCLUSION: It is concluded that the zona-slitting technique enhances fertilization of severely subfertile sperm, and its efficacy is affected by sperm morphology and a threshold concentration of motile cells.

Animals↗
PubMed1990

Mechanical factors in large artery disease and antihypertensive drugs.

Hypertension may induce early alterations in large arteries by 2 mechanical stresses: one related to intravascular pressure, the other to blood flow dynamics. Distending pressure force acts in a circumferential direction, inducing decreased arterial distensibility. Arterial distensibility can be evaluated in humans by measurement of arterial compliance and pulse-wave velocity. It is well established that in chronic hypertension age and elevated pressure act together to increase arterial rigidity. Blood flow dynamics induce frictional forces in the endothelial surfaces of arteries. These forces, expressed by shear stress, are proportional to the viscosity of the blood and to the velocity gradient at the arterial wall. Measurement of blood viscosity and evaluation of velocity profile in the brachial arteries of hypertensive subjects have shown a reduction in wall shear rate and stress despite the elevation in blood viscosity. Several studies have shown that drug therapy that successfully reduces blood pressure does not necessarily improve arterial compliance. In contrast, few data are available on the effects of antihypertensive medication on arterial wall shear in humans. Arterial compliance and wall shear stress are 2 main therapeutic targets of potential importance in the physiopharmacologic approach to the effects of hypertension on atherogenesis.

Antihypertensive Agents↗
PubMed1990

Ultrastructural evidence for a close relationship between dopamine cell processes and blood capillary walls in Macaca monkey and rat retina.

In the retina, tyrosine-hydroxylase (TH) antiserum specifically labels intrinsic dopamine (DA)-neurons. In order to clarify the relationship between capillaries and DA-processes already observed by light microscopy, we have performed TH-immunocytochemistry on rat and monkey retinas at the electron microscope level. Close contacts were observed between DA-varicosities and the basal lamina of both pericytes and endothelial cells. As in the brain, these anatomical findings suggest that intrinsic DA-neurons could contribute to the regulation of local retinal blood flow and/or permeability.

Animals↗
PubMed1990

Antithrombotic effects of recombinant hirudin in experimental angioplasty and intravascular thrombolysis.

The effect of recombinant desulphatohirudin CGP 39393 (rH) on arterial thrombus formation and especially on thrombotic reocclusion after experimental angioplasty as well as after thrombolysis was investigated in rabbits. In the femoral artery thrombi were induced after endothelial damage of the vessel wall by a balloon catheter and following stasis. After removing the thrombus by angioplasty or after lysing it by streptokinase reocclusion of the artery was observed within a relatively short period of time. Subcutaneous injection of rH reduced the incidence of both primary thrombus formation and reocclusion in dependence on the dose administered. After a dose of rH of 2 mg/kg s.c. arterial thrombus formation was completely prevented and after administering 4 mg/kg s.c. thrombotic reocclusion did also not occur. Comparative studies with heparin showed that similar antithrombotic effects were only achieved at doses of 12 mg heparin/kg s.c. The results obtained suggest a clear potential of rH for prevention of thrombotic reocclusion in clinical states.

Angioplasty, Balloon↗
PubMed1990

Effect of beta adrenoceptors and thyroid hormones on velocity and acceleration of peripheral arterial flow in hyperthyroidism.

Brachial artery flow patterns were studied in 10 hyperthyroid and 10 normal subjects. Mean blood velocity and flow were evaluated by pulsed Doppler, and peak systolic acceleration was calculated by computer-assisted digitization of the instantaneous velocity curve. Compared to control subjects, hyperthyroid patients had higher velocity and flow (p less than 0.01, p less than 0.02) and higher peak systolic acceleration (p less than 0.01). In hyperthyroid patients, measurements were repeated after (1) mechanical exclusion of the hand from brachial circulation, (2) short-term beta-blocker treatment and (3) inducement of the euthyroid state. Exclusion of the hand reduced velocity and flow (p less than 0.001) but did not change peak systolic acceleration. Beta blockade induced disparate changes of velocity and flow but reduced peak systolic acceleration (p less than 0.05). In the euthyroid state, decreased blood velocity (p less than 0.01), flow (p less than 0.02) and acceleration (p less than 0.02) were observed. A hyperkinetic arterial circulation consisting of an increase in both velocity and acceleration is thus observable in hyperthyroidism. Hand exclusion showed that velocity seems to be influenced by peripheral factors while beta blockade suggests that acceleration is dependent of beta 1 adrenoceptors. Comparison between euthyroidism and hyperthyroidism indicates that both mean blood velocity and peak systolic acceleration are influenced by thyroid hormones.

Adrenergic beta-Antagonists↗
PubMed1990

A new geometric procedure for in vivo pulsed Doppler evaluation of velocity distribution inside the diametrical section of large arteries in humans.

A new geometric procedure determination of velocity profiles inside large human arteries, such as the brachial and femoral, has been developed. The procedure requires the use of two crystal element Doppler probes and a highly precise micromanipulator with three degrees of freedom. Precise positioning is needed to obtain the required high degree of parallelism between the vessel axis and the plane containing the two crystal elements. Once the appropriate degree of parallelism is achieved, a controlled translation of the probe, perpendicular to the ultrasonic beam plane, allows velocity waveforms to be recorded at sequential radial positions across the measured artery. Velocity profiles obtained with this geometric procedure depended on the type of artery investigated. The profiles measured with the geometric procedure were more symmetrical than those found using the electronic range-gated time system of reception. While the geometric and electronic methods were almost identical in determining the diameter values of the three arteries measured, the geometric procedure enabled greater accuracy for detailed analysis of velocity profiles in the peripheral large arteries in humans. Although the present methodology is not applicable in clinical practice due to prolonged data acquisition time (approximately 45 s) it is expected that future equipment improvements will reduce this time significantly.

Adult↗
PubMed1990

Relation of risk factors for cardiovascular disease to early atherosclerosis detected by ultrasonography in middle-aged normotensive hypercholesterolemic men. PCV Metra Group.

The relations between carotid arteries and/or abdominal aortic plaque and cardiovascular risk factors were investigated by ultrasonography in 161 untreated hypercholesterolemic normotensive men. Of them, 58 had no plaque (NP group), 34 had carotid but not aortic plaque (CP group), 34 had aortic but not carotid plaque (AP group) and 35 had both carotid and aortic plaques (CAP group). Groups significantly differed for age, smoking, blood pressure, and the ratio of total to HDL cholesterol. Age was higher in CAP group than in NP and CP groups and in AP and CP groups than in NP group. Life long smoking dose was higher in CAP group than in CP, AP, and NP groups. Systolic and diastolic pressures were higher in CAP group than in NP group, systolic pressure was higher in CAP group than in CP group, and diastolic pressure was higher in AP group than in CP and NP groups. The ratio of total to HDL cholesterol was higher in CAP group than in AP, CP, and NP groups. Multiple regression analysis showed that carotid plaque was only related to age, while aortic plaque and the number of sites affected by plaque were correlated to age, smoking and diastolic pressure. These findings suggest that in hypercholesterolemia risk factors other than lipids seem to influence arterial plaque and that risk profile differs according to the plaque location.

Adult↗
PubMed1990

Sclerally directed processes of dopaminergic interplexiform cells reach the outer nuclear layer in rat and monkey retina.

Tyrosine hydroxylase-immunolabeled wholemounts and sections of rat and monkey retina were observed at both the light- and electron-microscopic level. Small processes derived from sclerally directed processes of dopaminergic interplexiform cells were observed ascending to the outer nuclear layer where they were distributed between photoreceptor cells. A role in the regulation of disc shedding and/or melatonin biosynthesis is proposed for dopamine released at this level.

Animals↗
PubMed1990

Dynamic association between artery shear flow condition and platelet cytosolic free Ca2+ concentration in human hypertension.

1. Blood cells and vascular endothelial cells are subjected to a wide range of haemodynamically generated shear stress forces. In vitro, membrane stretching or shear stress have been observed to activate ion channels and cell metabolism and to facilitate erythrocyte and platelet aggregation. 2. The present study was designed to evaluate the participation of shear stresses in the control of apparent platelet cytosolic free Ca2+ concentration in hypertensive patients. 3. Shear conditions and platelet cytosolic free Ca2+ concentration in vitro were studied after a dynamic perturbation induced by 3 months of double-blind treatment with one of two beta-antagonists, carteolol and atenolol. Brachial artery wall shear rate and stress were estimated by means of a pulsed Doppler velocimeter, and blood viscosity was measured by a co-axial viscometer at a shear rate of 96 s-1. Platelet cytosolic free Ca2+ concentration was simultaneously measured by using the Quin-2 fluorescent chelator. The direct effect of atenolol and carteolol on platelet cytosolic free Ca2+ concentration in vitro was also measured after addition of the beta-blockers to platelet-rich plasma. 4. Atenolol and carteolol decreased blood pressure similarly but their effects on shear rate (P less than 0.02), shear stress (P less than 0.01) and platelet cytosolic free Ca2+ concentration (P less than 0.05) differed after 3 months of therapy. In contrast, neither of the drugs significantly altered platelet cytosolic free Ca2+ concentration, in vitro per se. 5. In the overall population, strong positive correlations existed not only between changes in platelet cytosolic free Ca2+ concentration and those in shear rate (r = 0.81, P less than 0.001) and shear stress (r = 0.83, P less than 0.001), but also between their absolute values, suggesting a possible haemodynamic shear-dependent modulation of transmembrane Ca2+ transport.

Arteries↗