Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stress-strain diagrams of standardizised longitudinal and transversal stripes of the thoracic aorta of 125 male Sprague-Dawley rats aged 9, 15, 24 and 30 months were recorded by an electromechanical instrument. The stripes were subjected to three successive extension-relaxation cycles. The relaxation curves of the third cycle were approximated to the functions y = a + bx and y = cxd (longitudinal stripes) and y = mxf and y = gxh (transversal stripes) respectively. The parameters could be interpreted as measures for structural and functional properties of elastic and collagenous fibers. The age changes of the curve parameters led to the following conclusions concerning age-dependent functional alterations of the aorta: The emphasis can be placed upon the increasing resistance counteracting the extension occuring with great stroke volumes. This may lead to the reduction of the capacity of the air chamber with great stroke volumes. These phenomena seem to be mainly caused by an increase of the pitch of the spiral of the collagenic fiber and the increase of the amount and/or the stability of the collagen. Age-related alterations of the elastin and of the net structure formed by the fibers influence also the distensibility at smaller extensions but seem to be less important. Therefore, the structural alterations of the aorta with age will affect the function in the first place at large stroke volumes and not be very obvious at a basic heart performance.
 ...
PMID:[Tensibility measurements on the rat's aorta III. Analysis of longitudinal and transversal extension as related to age (authors transl)]. 2 73

Cardiac catheterization, angiocardiography and ventricular muscle biopsy were performed in forty patients with idiopathic cardiomyopathy and included 21 cases of hypertrophic cardiomyopathy and 19 cases of congestive cardiomyopathy. 1) Cardiac catheterization revealed normal cardiac index and stroke index in both types, although there was a slight tendency toward decrease in cases of CCM. HCM showed slightly elevated right ventricular end-diastolic pressure and left ventricular end-diastolic pressure with a high incidence of atrial kick. CCM showed an elevated mean pulmonary artery, mean pulmonary wedge and left ventricular end-diastolic pressure. 2) Angiocardiographic findings revealed that in HCM left ventricular end-diastolic volume as well as left ventricular end-systolic volume, ejection fraction, meanVcf and MNSER were within normal range, and left ventricular anterior wall thickness, left ventricular mass and shortening of short axis in systole were increased. In CCM left ventricular end-diastolic volume and end-systolic volume increased, and ejection fraction, meanVcf, MNSER were decreased. The left ventricular anterior wall thickness was normal, and the left ventricular mass was smaller compared to the volume. The shortening of long and short axes in systole was slight. Left ventricular asynergy and mitral regurgitation occurred frequently. Coronary cineangiograms revealed normal patterns in both types. 3) Histological findings revealed hypertrophy of myofibers, degenerative changes, i.e. scarcity of myofibrils, deformity of nucleus and vacuolization of myocardial fibers, and collagen proliferation in both types. 4) No definite relationship was seen between parameters of left ventricular function and the findings of biopsied left ventricular muscle except for increase in wall thickness which might be apparently due to hypertrophy of the myocardial fibers.
 ...
PMID:Angiocardiograms and hemodynamics in idiopathic cardiomyopathy, with reference to histology of biopsied ventricular myocardium. 15 67

Ischemic optic neuropathy and retinal arterial occlusion are 2 forms of arterial occlusive disease affecting the eye. Reports in the literature suggest platelet hyperactivity in acute arterial occlusive diseases affecting other organ systems. Therefore, 14 patients with ischemic optic neuropathy and 17 patients with central or branch retinal artery occlusion were studied to determine whether platelets have a role in the pathogenesis of these vascular occlusive disorders. The results of the following investigations were no different in these patients compared with those in 18 control patients with non-vascular eye diseases: prothrombin times, partial thromboplastin times, plasma fibrinogen, factor V, factor VIII, platelet counts and threshold concentrations of ADP, epinephrine and collagen resulting in secondary platelet aggregation and serotonin release. In contrast, platelet coagulant activities concerned with the early stages of intrinsic coagulation were significantly increased in patients with retinal artery occlusion without hypertension or type IV hyperlipoproteinemia, but generally normal in patients with ischemic optic neuropathy and in patients with retinal artery occlusion associated with hypertension, type IV hyperlipoproteinemia, diabetes mellitus and generalized atherosclerosis. These results are consistent with a platelet contribution to retinal arterial occlusive disease in patients without other known contributing factors such as hypertension, serum lipid abnormalities, diabetes mellitus and generalized atherosclerosis and may have implications regarding prophylaxis.
Stroke
PMID:Platelet coagulant activities in arterial occlusive disease of the eye. 50 1

Chemical characteristics of vascular collagen were studied in stroke-prone spontaneously hypertensive rats (SHRSP) which developed cerebrovascular lesions spontaneously in over 90% of the population. Aminoacid analysis of arterial collagen among SHRSP showed no remarkable difference from stroke-resistant SHR (SHRSR) and normotensive Wistar-Kyoto rats (WK). The uronic acid content of the aorta, which elevated with aging, was increased in SHRSR and especially in SHRSP. The hexose content of collagen was also increased in SHRSP characteristically with a concomitant increase in the ratio of the disaccharide unit (glucosyl-galactosyl-hydroxylysine) to the monosaccharide (galactosyl-hydroxylysine). The relative increase in beta and gamma components was also noted in SHRSP. These structural changes of vascular collagen especially noted in SHRSP may be related to the fragility of arterial wall or to the stroke-proneness.
 ...
PMID:Chemical analysis of vascular collagen in stroke-prone spontaneously hypertensive rats. 51 69

1. The chemical characteristics of the vascular connective tissue components were determined in stroke-prone (SP), stroke-resistant (SR) spontaneously hypertensive (SH) rats and normotensive Wistar-Kyoto (WK) rats. 2. The ratio of hydroxylysine to hydroxylsine plus lysine in the vascular collagen was increased in 6-month-old SP-SH rats and SR-SH rats as compared with WK rats. 3. An age-related increase in uronic acid and hexose content of the aorta was noted in SP-SH, SR-SH and WK rats. However, the increase was more prominent in SH rats, especially SP-SH rats at the stages examined (11 weeks and over 8 months of age). 4. The ratio of galactosyl-hydroxylysine to glucosyl-galactosyl-hydroxylysine in the aortic collagen was decreased in 6-month-old SH rats, especially SP-SH rats as compared with WK rats. 5. A relative increase in beta and gamma components in aortic collagen was noted in 6-month-old SP-SH rats when compared with SR-SH rats. 6. The increased content of uronic acid and hexose and the structural changes of vascular collagen as demonstrated in SP-SH rats might be related to the fragility of the arterial wall and/or to the pathogenesis of stroke-proneness.
 ...
PMID:Biochemical alterations of connective tissue metabolism in the arterial walls of stroke-prone spontaneously hypertensive rats. 54 Apr 54

Recent epidemiologic studies have suggested that cardiac disease in common in diabetics and may often have a noncoronary basis. To examine the status of the left ventricle, 17 adult-onset diabetics of familial type without hypertension or obesity underwent hemodynamic study and were compared to 9 controls of similar age. Of the 17, 12 subjects had no significant occlusive lesions by coronary angiography. From this group eight without heart failure had a modest, but significant, elevation of left ventricular end-diastolic pressure. End-diastolic and stroke volumes were reduced, but ejection fraction and mean rate of fiber shortening were within normal limits. The left ventricular end-diastolic pressure/volume ratio was significantly higher than controls. Afterload increments effected a significant increase of filling pressure compared to normals without a stroke volume response, consistent with a preclinical cardiomyopathy. Four patients with prior heart failure had similar but more extensive abnormalities. None had local dyskinesia by angiography, and lactate production was not observed during pacing-induced tachycardia. Left ventricular biopsy in two patients without ventricular decompensation showed interstitial collagen deposition with relatively normal muscle cells. These findings suggest a myopathic process without ischemia. Postmortem studies were performed in 11 uncomplicated diabetics. Nine were without significant obstructive disease of the proximal coronary arteries, and the majority succumbed with cardiac failure. On left ventricular sections, none had evident luminal narrowing of the intramural vessels. All nine exhibited periodic acid-Schiff-positive material in the interstitium. Collagen accumulation was present in perivascular loci, between myofibers, or as replacement fibrosis. Multiple samples of left ventricle and septum revealed enhanced triglyceride and cholesterol concentrations, as compared to controls. Thus, a diffuse extravascular abnormality may be a basis for cardiomyopathic features in diabetes.
 ...
PMID:Evidence for cardiomyopathy in familial diabetes mellitus. 89 79

Apoproteins from plasma lipoproteins were localized by immunofluorescence techniques in human carotid artery atherosclerotic lesions. These studies were performed in light of the possible importance of these apoproteins in both lipid metabolism and the pathogenesis of atherosclerosis. ApoA-I from high density lipoproteins, apoB from low density lipoproteins, and apoC-III from very low density lipoproteins were localized also as markers for their respective lipoproteins, since the latter cross-react immunologically. The three apoproteins were localized to the same regions of lesions as neutral lipids and, to some extent, fibrinogen. These regions consisted of bands of collagen fibers, usually deeper within the lesion, and the lipid core or atheroma of such advanced lesions. Although the superposition of localization for the three apoproteins and lipid was only 53%, it was suggested that deviation from complete superposition was due to the abrupt changes in lesion structure resulting from the focal nature of the atherosclerotic process. These results suggest that there is a broader specificity than previously implied of the interaction between such lesion components as connective tissue and extracellular lipid accumulations, and apoproteins from plasma lipoproteins. This interaction is believed to result in a net retention within atherosclerotic lesions of human extracranial arteries of these plasma-derived factors, either as free apoproteins or as native lipoproteins.
Stroke
PMID:Localization of apo-lipoproteins in human carotid artery plaques. 117 63

Biphasic collagen-induced platelet aggregation, resembling that induced by epinephrine, was noted in platelet-rich plasma (PRP) of 11 stroke and 1 coronary disease patients. Similar pattern of aggregation was not observed in normal PRP. The occurrence of the biphasic collagen aggregation does not appear to relate to platelet count, smoking habit, medication, or other abnormalities such as hypertension, diabetes, and elevated serum lipid levels. However, platelets of these patients were very sensitive to aggregating agents including epinephrine and adenosine diphosphate. The concentration of collagen that elicited biphasic aggregation in these platelets was too weak to aggregate platelets of normal subjects. We believe that the release threshold of these platelets is reduced to such an extent that minute amounts of collagen, which would be insufficient to induce release from normal platelets, are capable of inducing release from these platelets. Both phases of collagen induced aggregation are probably resulted from the activation of the release mechanism.
 ...
PMID:Characterization and significance of collagen induced biphasic aggregation of human platelets. 119 59

The abuse of anabolic-androgenic steroids by athletes has recently been associated with the development of myocardial infarction and stroke. Because platelets play a pathogenic role in these disorders, the authors hypothesized that androgenic steroid abuse among weight lifters was associated with increased platelet aggregation as measured in vitro. Twenty-eight study participants were recruited. Twelve denied current androgen use. However, 8 of these 12 tested positive for urinary androgens. Nonsignificant trends toward increased platelet counts and increased platelet aggregation to adenosine diphosphate were noted when androgen users were compared to nonusers. However, when stratified by age, older (greater than 22 years) androgen users required lower concentrations of collagen to produce 50% aggregation of test platelets than did younger (less than or equal to 22 years) androgen users (1.47 versus 3.35 micrograms/ml; p = .01). Further subgroup analysis revealed nonsignificant trends toward increased adenosine diphosphate-induced aggregability and nonsignificant trends in the platelet count in older weight lifters. Subsequent studies using collagen threshold aggregometry revealed no age-dependent effect in 17 other men (aged 18 to 46 years) not specifically selected for activity (r = .17). This study suggests an association between androgen use, age, and increased platelet sensitivity to collagen in weight lifters and may be helpful in explaining recent thrombotic disease in androgen users. It additionally calls into question the validity of subjective reporting when assessing androgen use among weight lifters.
 ...
PMID:Androgenic-anabolic steroid abuse and platelet aggregation: a pilot study in weight lifters. 153 13

The molecular states of collagen in the aortas of age-matched stroke-prone spontaneously hypertensive (SHRSP) and normotensive Wistar Kyoto rats (WKY) were studied by analyzing its extractability under defined conditions. The monomeric and oligomeric collagen extractable with 0.5 M acetic acid/6 M urea from aortic homogenates of 9-month-old SHRSP and WKY comprised approx. 0.6 and 2.0%, respectively, of the total collagen. On incubation of the acetic acid/urea-extracted residues with pepsin at 4 degrees C, the levels of the collagen alpha 1(I) and alpha 2(I) chains solubilized from the SHRSP residues were both less than 50% of those from the WKY residues. When the residues were incubated with pepsin at 15 or 25 degrees C, the differences became smaller. When the acetic acid/urea residues were hydrolyzed with cyanogen bromide, nearly identical peptide maps were obtained for SHRSP and WKY. The aortas from 2-month-old SHRSP and WKY contained much larger proportions of acid/urea-extractable collagen than those of the older rats (8.2 and 13% of the respective total collagen). The levels of the alpha 1(I) and alpha 2(I) chains solubilizable from the respective residues by pepsin at 4 degrees C were similar to each other. These results indicate that aortic collagen fibrils in SHRSP are stiffened more prominently than those in WKY.
 ...
PMID:Comparative studies on the extractability of collagen from aortas of stroke-prone spontaneously hypertensive and normotensive rats. 161 Sep 9


1 2 3 4 5 6 7 8 9 10 Next >>