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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A two-dimensional framework can be used for considering the characteristics of left ventricular ejection in terms of the appropriateness of the matching between afterload and the level of inotropic state, as modulated by the preload reserve. An afterload mismatch (reduced velocity and extent of shortening) can be induced acutely in the normal heart under controlled conditions if the preload is not allowed to compensate for an increased afterload, or if the limit of preload (Frank-Starling) reserve has been reached. In the intact circulation the normal heart is sensitive to some degree to acute changes in afterload, perhaps due to impaired venous return; but under basal resting conditions the ejection phase measures (such as the ejection fraction and the mean velocity of circumferential fiber shortening or VCF, corrected for heart size) encompass a relatively narrow range. This finding, and the lack of change in ejection phase measures after the normal heart has adapted to a chronic pressure or volume overload, provides justification for the use of ejection phase indices for detecting depressed inotropic state under basal conditions. When there is mild depression of myocardial inotropic state, with or without accompanying mechanical overload, enhanced preload may allow full compensation, but acute pressure loading may allow early detection of a less than normal preload reserve. When the inotropic state is substantially reduced, however, a mismatch between afterload and contractility (a reduction in mean VCF) will become evident even in the basal state (venous return being presumed to be adequate under these conditions). The concept of afterload mismatch with limited preload reserve provides an explanation for the value of ejection phase indices compared to isovolunic phase measures in assessing the basal level of inotropic state: the former may be more reliable because they are sensitive to afterload. The effects and implications of therapeutic afterload reduction as modulated by the preload also are understood within this framework.
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PMID:Afterload mismatch and preload reserve: a conceptual framework for the analysis of ventricular function. 12 34

Previous studies of the effect of angiotensin on myocardial contractility have yielded conflicting results. Possible reasons for the observed disparities include differences in techniques for measuring contractility, in species (dog, cat, and man), in myocardial state (normal or diseased), in preparation observed (heart-lung, isolated heart, papillary muscle, atrial myocardium, intact heart), and in dosage schedule. Moreover, there are no reported studies in the intact human heart, normal or diseased, in which contractility measurements are based on velocity-force relations. To resolve the conflict, left ventricular myocardial contractility was measured using the same expressions for the force-velocity relationship in all subjects. Studies were performed in five normal human subjects, six patients with cardiomyopathy, eight normal mongrel dogs, and six dogs with ischemic myocardial scarring, before and during angiotensin infusions in dosages producing 15--20-mm Hg increases of aortic diastolic pressure. Contractile element velocity at peak, dP/dt (Vce) and the Frank-Levinson contractility index (CyIx), which normalizes Vce for diastolic fiber length, decreased during angiotensin infusion in all groups. The mean decreases (11 to 19) per cent in Vce, 15 to 23 per cent in CyIx, SEM's 4-5 per cent) were significant (P values ranging from smaller than 0.05 to smaller 0.005) in the normal hearts of dogs and man and in the scarred canine hearts, in which preangiotensin Vce and CyIx were normal. In the cardiomyopathy group, in which contractility was depressed before angiotensin, the drug elicited a further decrease in Vce (mean fall 17 plus or minus 7 per cent, P smaller than 0.1) and CyIx (26 plus or minus 8 per cent, P smaller than 0.02). We conclude that, in the intact organism, with a normal myocardium or a diffuse or segmental myocardial disease, the administration of angiotensin results in a depression of contractility.
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PMID:The effect of angiotensin on myocardial contractility. 23 32

The action of 21 purine compounds on the twitch response of the electrically stimulated guinea pig isolated ileum has been investigated. Adenosine and related compounds produced a dose-dependent depression of the response. Adenosine was the most potent and 2'-deoxyadenosine had one hundredth the potency of adenosine. Adenine, hypoxanthine, inosine, IMP, ITP, xanthine, xanthosine, XMP, XTP, guanine, GMP and GTP were ineffective at concentrations less than 1 mM. Adenosine (30 microgram) reduced the electrically induced ACh output from the ileal strips. The dose--depression curve for adenosine (0.1--30 microgram) was shifted to the right in the presence of xanthine derivatives and of these, theophylline was the most potent inhibitor of adenosine. On the other hand, dipyridamole (0.1--1 microgram) and hexobendine (0.1--1 microgram) shifted the curve to the left. They markedly inhibited 3H-adenosine uptake into the ileum. Theophylline (0.1 mM), dipyridamole (0.3 microgram) and hexobendine (0.3 microgram) did not affect tetrodotoxin-, adrenaline-, strychnine- and morphine-induced inhibition of the twitch response. The present investigations have revealed that adenosine and related compounds reduce ACh release from the intramural cholinergic nerves in the guinea pig ileum possibly in a specific manner (or through a specific receptor site) different from that of other inhibitors such as morphine.
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PMID:Effects of purine compounds on cholinergic nerves. Specificity of adenosine and related compounds on acetylcholine release in electircally stimulated guinea pig ileum. 63 57

The characteristics of left ventricular ejection (velocity and extent of wall shortening) can be analysed in relation to the appropriateness of the matching between afterload and the level of inotropic state (contractility), as modified by the preload (Frank-Starling) reserve. In the normal left ventricle if the preload is not allowed to compensate for an acute increase in afterload, or if the limit of preload reserve is reached, velocity (V CF) and stroke volume will diminish; that is an afterload mismatch occurs. This acute mismatch can be corrected by administration of a positive inotropic agent. In normal conscious animals and in man the ejection phase measures in the basal state (such as ejection fraction, and VCF corrected for heart size) encompass a relatively narrow range, and when the normal heart adapts successfully to a chronic pressure or volume overload such measures remain normal per unit of muscle. These findings provide the basis for their use in detecting a depressed basal level of inotropic state, even in the presence of certain valvular lesions. When there is mild depression of the basal inotropic state, enhanced preload and dilatation can allow full compensation of VCF, but acute pressure loading can allow detection of the the reduced preload reserve by inducing a substantial fall in stroke volume and VCF. When the basal inotropic state is greatly reduced, a mismatch between afterload and contractility, expressed as reduced VCF or ejection function, will become evident in the basal state even if the afterload is normal. Any increase in aortic pressure will then cause a sharp reduction in stroke volume or VCF. Also, under these circumstances therapeutic afterload reduction with agents such as nitroprusside can increase velocity and extent of wall shortening, and the cardiac output, providing the preload is maintained. The concept of afterload mismatch with limited preload reserve provides a framework for understanding the behavior of the normal or depressed ventrile and how it can operate on a "descending limb" of function. It helps to explain why measures of the ejecting phase (which are sensitive to afterload) appear to be more reliable than isovolumic phase indices (which are relatively insensitive to afterload) for detecting depressed basal inotropic state. Finally, the concept allows for interpretation of the responses observed in the clinical setting to acute and chronic increases and decreases in loading conditions on the left ventricle.
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PMID:The concept of afterload mismatch and its implications in the clinical assessment of cardiac contractility. 96 66

Of ten healthy women, 43 to 61 years of age, four exhibited 1 mm. or more of upsloping ST-segment depression after maximal exercise, using the Bruce multistage treadmill protocol; the other six did not. Cardiac output (direct Fick) was not different in the two groups, wither at rest or during exercise. The women with ST-positive responses were older (56 vs. 51 years) and heavier (relative weights 109 per cent vs. 102 per cent), and their resting mean systemic pressures were higher. Their systemic and pulmonary mean arterial pressures during the last five minutes of upright exercise were significantly higher (P less than 0.001) than those in the ST-negative group. Although the ratio of systemic to pulmonary mean arterial pressures was higher at rest, it progressively fell during exercise in the ST-positive group. Polarcardiographic display of the Frank ECG during the first 3 minutes of recovery after maximal exercise showed significant differences between the ST and T of the two groups. At initial recovery, MS-phi greatly exceeded 10.6 mV. which is sensitive PCG ischemic exercise criterion in the ST-positive group. Although the number of observations is limited, it is concluded that greater hemodynamic stress imposed on the subendocardium by elevated pressures, rather than by any significant functional evidence of restriction in coronary blood flow, probably explains much of the postexertional ST-segment depression after maximal exercise.
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PMID:Elevated arterial pressure and postexertional ST-segment depression in middle-aged women. 98 33

A heart model in dogs was developed to evaluate quantitatively the extent to which left ventricular chamber size could be reduced and yet retain residual mechanical function to perform adequately as a pump. In 9 animals placed on right heart bypass perfusion to control systemic flows; left ventricular performance was estimated from high-fidelity left ventricular pressure and aortic flowmeter recordings and from lateral plane left ventricular angiograms. Studies were made during unrestricted left ventricular filling at varying cardiac outputs and with inflation of a balloon in the left ventricular cavity at a physiological cardiac output. As compared with control data (cardiac output 1.4 L. per minute), balloon inflation to 18.7 ml. caused an increase in total left ventricular end-diastolic volume (from 35.4 to 44.3 ml., p less than 0.001) and left atrial pressure (from 7.8 to 21.2 mm. Hg; p less than 0.001); it also caused a reduction in left ventricular stroke work (from 12.5 to 8.1 Gm.-M., P LESS THAN 0.005) ANd max. dp/dt (from 2,487 to 1,320 mm. Hg per second, p less than 0.05). Importantly, left ventricular stroke volume was unchanged. When compared with preload augmentation (with the balloon deflated), the magnitude of depression of cardiac performance caused by balloon inflation was more fully appreciated (left ventricular stroke work, max. dp/dt, and ejection fraction reduced 69, 61, and 45 per cent, respectively). Even so, with appropriate compensations, principally by the Frank-Starling mechanism, up to 42 per cent of the left ventricular cavity volume could be functionally eliminated with retention of adequate mechanical performance. Such data may have implications regarding the extent of resections possible in patients undergoing surgery for left ventricular aneurysm.
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PMID:Functional reductions in left ventricular volume. Minimum chamber size consonant with effective hemodynamic performance. 124 44

Although the endogenous subtype in depression has long been thought to have prognostic significance, to date no long-term maintenance treatment trial has examined the relative risk of recurrence in patients meeting criteria for this subtype. Following our analysis of the primary hypotheses regarding the relationship between treatment assignment and outcome [Frank et al. (1990) Arch. Gen. Psychiatry 47, 1093-1099], we now examine psychobiologic and maintenance treatment correlates for these recurrent unipolar patients grouped according to melancholic, endogenous but not melancholic, and non-endogenous subtype at index presentation. No differences were observed among the three groups in overall survival time; however, in the 52 patients who received psychotherapy without active medication during the maintenance phase, length of survival was inversely related to endogeneity. Interestingly, no differences were found among the three groups in EEG sleep parameters when studied either at baseline or following recovery.
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PMID:Maintenance treatment and psychobiologic correlates of endogenous subtypes. 152 73

In patients with coronary artery disease, radionuclide investigations have documented a high incidence of mental stress-induced myocardial ischemia in the absence of significant electrocardiographic changes and/or angina. To investigate the causes of the low electrocardiographic sensitivity, we recorded body surface maps during mental arithmetic in 22 normal volunteers and 37 postinfarction patients with residual exercise ischemia. Myocardial perfusion was studied with thallium-201 or technetium-99 (SESTAMIBI) planar scans. In 14 patients, body surface maps were also recorded during atrial pacing at the heart rate values achieved during mental stress. While taking the body surface maps, the area from J point to 80 msec after this point (ST-80) was analyzed by integral maps, difference maps, and departure maps (the difference between each patient's difference map and the mean difference map for normal subjects). The body surface mapping criteria for ischemia were a new negative area on the integral maps, a negative potential of more than 2 SD from mean normal values on the difference maps, and a negative departure index of more than 2. Scintigraphy showed asymptomatic myocardial hypoperfusion in 33 patients. Eight patients had significant ST segment depression. The ST-80 integral and difference maps identified 17 ischemic patients. Twenty-four patients presented abnormal departure maps. One patient presented ST depression and abnormal body surface maps without reversible tracer defect. In 14 of 14 patients, atrial pacing did not reproduce the body surface map abnormalities. The analyses of the other electrocardiographic variables showed that in patients with mental stress-induced perfusion defects, only changes of T apex-T offset (aT-eT) interval in Frank leads and changes of maximum negative potential value of aT-eT integral maps significantly differed from those of normal subjects. Our results confirm the low electrocardiographic sensitivity for detecting mental stress-induced myocardial hypoperfusion in postinfarction patients. ST analysis in the body surface map increases the information content of the electrocardiographic signal. T wave analysis appears to offer fewer diagnostic advantages.
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PMID:Electrocardiographic markers of ischemia during mental stress testing in postinfarction patients. Role of body surface mapping. 182 36

Direct radioimmune assay (RIA) have been developed for detection of antibodies associated wild platelet membrane. Platelets from 12 patients with idiopathic thrombocytopenic purpura (ITP) and 27 patients with chronic lymphocytic leukemia (CLL) (platelet count (100,000 in 1 microliters) have been tested. Antibodies on platelets surface have been detected in all 12 patients with ITP and in 21 patients with CLL. In 6 CLL patients the number of immunoglobulins associated with platelets surface does not increase control level. It is possible, that in some CLL patients development of thrombocytopenia is mediated not only by platelet associated antibodies but by other mechanisms, one of which can be linked with the depression of megakaryocytes growth in bone marrow. Direct RIA for measurement of antibodies on platelet surface detect antiplatelet antibodies with higher frequency than indirect enzyme-linked-immunosorbent-assay (ELISA), developed earlier for assessment of antiplatelet antibodies in serum. Increase of platelet count in CLL patients after steroid and cytostatic treatment correlated with the decrease of platelet surface associated antibodies.
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PMID:[Determination of antiplatelet antibodies on the surface of platelets by direct radioimmune method in patients with different types of immune thrombocytopenia]. 189 96

During the months of April and May of 1985, 3218 individuals were studied, in the city of Valencia, Carabobo State, Venezuela, there were chosen at random out of the population whose ages ranged between 15 years and over. A two parts questionnaire was made consisting on the Self-rating Depression Scale by Zung, and the study of socioeconomic factors of the individuals. Frank depression was found in 36.8% of individuals and 55% tendency towards depression, with a mean depression index of 0.48 and a standard deviation of 0.12. The groups that showed the largest prevalence of frank depression were: females 40.4%, ages ranging between 65 years and over 46.2%, widowhood 70.7%, illiterates 65.8%, crippled 50%, and those with low grade of satisfaction with their actual occupation 55.2%. These data suggest the high frequency of Depressive Syndrome in the studied population, and also the strong relationship existing between this syndrome and socioeconomic factors implicated.
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PMID:[Prevalence of depression syndrome and its relationship with socioeconomic factors in a population of Valencia City, Carabobo state, Venezuela]. 215 46


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