Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surgical occlusion of the left coronary artery of the rat is a relatively simple, economical technique for producing experimental myocardial infarction (MI). Histologic study of 1- to 21-day-old MI in rats showed that following a mild and brief acute inflammatory response at the margins of the necrotic myocardium, there is chronic inflammation, vascular and collagenous proliferation, and resorption of necrostic tissue which progresses until scar formation is complete, usually by 21 days. From Day 1 to Day 21 the volume of infarcted myocardium decreases from 45.9 +/- 5.9% (mean +/- SEM) to 26.1 +/- 3.2% of the left ventricle and infarct thickness decreases from 1.30 +/- 0.06 mm to 0.47 +/- 0.02 mm. Concomitantly, the percent of the surface area of the left ventricle which is infarcted decreases insignificantly from 55.7 +/- 7.2% to 48.3 +/- 4.2%, indicating that the decrease in volume of the infarcted tissue occurs primarily as a result of thinning of the MI. This study provides qualitative and quantitative information on the natural history of MI in rats, which should be useful as a baseline for future studies.
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PMID:Experimental myocardial infarction in the rat: qualitative and quantitative changes during pathologic evolution. 61 96

We studied lung explants in submersion organ culture to examine the role of the developing fetal alveolar epithelium in the production of lung fluid. Fourteen-day-gestation fetal rat lungs were grown in a collagen gel matrix supplemented with F-12 media and 10% fetal calf serum. In this model, the lung continues to grow, secrete fluid, and become progressively cystic in morphology. There is gradual thinning of the distal epithelial layer, which is lined by alveolar type II cells and their precursors. After 6 to 8 days in culture, we impaled the cyst walls with a microelectrode and continuously recorded the transepithelial potential (psi t). Stable, baseline transepithelial potentials of -1.1 to -6.2 mV (mean +/- SEM = -3.3 +/- 0.11 mV, lumen negative, n = 34) were measured in bicarbonate-buffered Ringer's solution, suggesting active electrolyte transport. When bumetanide, an inhibitor of chloride secretion in other systems, was added to the bathing solution, psi t decreased from a baseline of -3.5 +/- 0.07 mV (mean +/- SEM) to a value of -2.2 +/- 0.07 mV, suggesting chloride transport contributes to the voltage (n = 18, P less than 0.0005). Isoproterenol hyperpolarized psi t from a baseline of -4.3 +/- 1.0 mV to -6.5 +/- 1.0 mV (n = 7, P less than 0.005). 8-(4-Chlorophenylthio) adenosine 3':5'cyclic monophosphate (CPT-cAMP) plus isobutylmethylxanthine (IBMX) similarly hyperpolarized psi t from a baseline of -4.6 +/- 0.4 mV to -7.3 +/- 0.7 mV (n = 11, P less than 0.005). Addition of bumetanide after stimulation with isoproterenol or CPT-cAMP/IBMX depolarized psi t.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Secretion of lung fluid by the developing fetal rat alveolar epithelium in organ culture. 131 92

Rats from the H-Tx strain develop hydrocephalus through a developmental obstruction of the cerebral aqueduct. The progressive ventriculomegally is accompanied by thinning of the cerebral cortex which is already present 10 days after birth. However, a previous study found that the CSF pressure was not significantly raised until 21 days after birth. New experiments have now been performed over a 90 min. period using control and hydrocephalic 10-day-old rats under light pentobarbitone anaesthesia, in order to study the level, time-course and morphology of the resting intraventricular pressure. The mean pressure and its fluctuations were calculated for each minute. Control rats had a mean pressure of 19.3 +/- 1.23 (SEM) mm H2O (n = 9, range: 13.6-24.7) and in hydrocephalic rats, pressure was significantly higher at 23.5 +/- 1.13 mm H2O (n = 9, range: 18.1-28.3). There was no consistent trend with time and no significant difference between groups in pressure fluctuations, but at least two of the hydrocephalic rats showed episodic waves similar to "B"-waves in humans.
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PMID:Cerebrospinal fluid pressure in 10-day-old rats with congenital hydrocephalus. 180 75

Using light, transmission (TEM) and scanning (SEM) electron microscopy, cocaine-induced defects were observed in hamster atria. Compared with controls, the treated atria from neonates show endocardial and myocardial damages as the atrial walls thicken. SEM micrographs show intensive blebbing, damage and incomplete coverage of myocardium by the endocardial endothelium. TEM data demonstrate blebs, thinning, and other endothelial cell injuries and complement the SEM findings. Areas of endothelial sloughing may facilitate the formation of luminal and mural thrombi as noticed in many neonatal atria. Adjacent subendocardial myocardial cells display contraction bands, swellings, and vacuolizations. Local and large areas of damaged myocardial cells are observed in the subendothelial spaces; they contact fibroblasts squeezed or intercalated between the subendocardial spaces and the basal side of damaged endothelial cells. Many of these defects correspond to well-known ischemic changes. One can hypothesize that cocaine-induced defects appear to be linked to membranous alterations, including those associated with the endothelial cells of the endocardium.
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PMID:Transplacental cardiotoxicity of cocaine: atrial damage following treatment in early pregnancy. 194 34

The effects of reperfusion on myocardial infarct healing in the rabbit were analyzed using two morphometric indexes: the ratio of the volume of the organized portion of infarct to the volume of the whole infarct (%O/I), and the ratio of the minimal thickness of the infarct zone to the normal zone thickness (thinning ratio). In the nonreperfused infarcts, %O/I increased from 43.8 +/- 3.1% (mean +/- SEM) at 48 h to 85.7 +/- 2.5% at seven days, which supported the validity of this index. The thinning ratio was 0.50 +/- 0.03 at 48 h and did not change during the following five days. In other groups of rabbits, the coronary artery was temporarily occluded for 30 mins (early reperfusion) or 60 mins (late reperfusion), and the hearts were analyzed at 72 h or seven days. Early reperfusion limited infarct size as a percentage of the area at risk (%I/AAR) by approximately 50%, but late reperfusion did not. In both nonreperfused and reperfused infarcts, %O/I correlated significantly with absolute infarct size. Furthermore, the regression lines of the relationship of infarct size to %O/I of early and late reperfused infarcts shifted towards higher %O/I values compared with that of nonreperfused infarcts at seven days, which suggested accelerated organization. However, such a regression line shift by reperfusion was not detected at 72 h after infarction. The thinning ratio was higher in early reperfused infarcts compared to nonreperfused or late perfused infarcts, and there was a weak inverse correlation between thinning ratio and %I/AAR when the data of reperfused and nonreperfused infarcts were pooled.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of early and later reperfusion on healing speed of experimental myocardial infarct. 204 18

Adult laying domestic ducks (Anas platyrhynchos domesticus) were forced fed lindane (gamma-hexachlorocyclohexane) 20 mg/kg body weight daily, thrice/week and twice/week for 8 weeks. Significant shell thinning (18-21%) was observed in ducks with daily and thrice/week lindane feeding. SEM studies of thinned eggshells revealed reduced and tightly clustered mammillae with apparent decrease in intermammillary spaces and signs of inhibition of calcite formation. Such structural changes of thinned shells were associated with a significant reduction in the level of calcium both of the plasma and of shell gland of the ducks. Simultaneously, density of the pore in the shell and pore area/cm2 of the shell in these birds were drastically reduced, presumably because of total absence of 'large' pores in such shells. Such porosity change is suggestive of reduced conductivity of eggshell implying impaired hatching success. Diethyl stilboestrol post-treatment neutralized all the adverse effects of lindane on duck eggshell, indicating induced estrogen deficiency in such birds by lindane.
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PMID:Effect of lindane on eggshell characteristics and calcium level in the domestic duck. 243 94

To assess the time-course of adaptive responses of the left ventricle to chronic volume overload, dogs were instrumented with a left ventricular (LV) micromanometer and pairs of ultrasonic crystals for the measurement of LV wall thickness (WTh), LV chamber diameter (D), and longitudinal segment length (L). Following a control study, mitral regurgitation (MR) was created by a transventricular section of the chordae tendineae. Heart rate was controlled during each study by atrial pacing. Plasma norepinephrine levels at rest were determined by high-performance liquid chromatography. Eight days (mean) after the onset of MR, enddiastolic (ED) D had increased by 9% from 34.2 +/- 2.4 mm (SEM) (P less than 0.001), with significant thinning of the wall thickness (from 8.2 to 7.7 mm, P less than 0.001). Consequently the calculated cross-sectional area (CSA) of the left ventricular wall remained the same. Peak wall stress (WSt) and EDWSt increased by 20% and 152%, respectively. During the subsequent 4 weeks, EDD progressively increased, averaging 11% above the control at 4 weeks, while EDWTh returned to the control level. Thus, the development of hypertrophy was clearly evidenced by an increase in CSA (by 8% over the control, P less than 0.001). These changes were accompanied by a consistent reduction in both peak WSt and EDWSt. Mean velocity of circumferential fiber shortening (meanVcf) and percentage shortening were significantly augmented following the onset of MR and remained at the same level thereafter, indicating no further use of the Frank-Starling mechanisms during chronic ventricular dilation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adaptations of the left ventricle to chronic volume overload induced by mitral regurgitation in conscious dogs. 293 15

Isolated rat heart preparations were studied to characterise the alterations in high energy phosphates that occur during reversible regional ischaemia and to determine whether pyruvate, as the sole exogenous energy substrate, would attenuate the ischaemia induced depletion of the nucleotide pool when compared with glucose. Using phosphorus-31 magnetic resonance spectroscopy baseline concentrations of adenosine triphosphate, phosphocreatine, inorganic phosphate, and intracellular pH were compared with values during 30 min of left coronary artery occlusion followed by 30 min of reperfusion. These variables were related to changes in developed pressure, coronary flow, and oxygen consumption. In addition, the total nucleotide pool was evaluated by biochemical analysis of myocardial tissue extracts and coronary effluent. The ischaemic region was characterised by a dye staining technique and cross sectional echocardiographic measurements of regional myocardial wall thinning. In both glucose and pyruvate perfused groups, coronary flow and oxygen consumption decreased to 50-60% of control within 1 min of ischaemia and returned to baseline values with reflow. Developed pressure decreased to 50(9) and 74(8)% (mean(SEM] of control after 30 min of ischaemia in glucose and pyruvate perfused groups respectively. Reperfusion resulted in complete recovery of developed pressure in hearts perfused with pyruvate but not in the glucose group. Glucose perfused hearts had a greater decrease in intracellular pH during ischaemia (7.07(0.01) to 6.36(0.1] than pyruvate perfused hearts (7.06(0.02) to 6.83(0.04]. Reperfusion resulted in a rapid return to baseline intracellular pH in both groups. During ischaemia, adenosine triphosphate values decreased to a greater degree in glucose than in pyruvate perfused hearts (57(4) and 79(5)% of baseline respectively). Thirty minutes of reperfusion did not significantly improve adenosine triphosphate concentrations in either group. Phosphocreatine concentrations decreased to 52(7) and 75(6)% of baseline in glucose and pyruvate perfused groups respectively after the ischaemic period. Reperfusion resulted in normalisation of phosphocreatine values in the pyruvate but not in the glucose perfused group. Biochemical analysis of myocardial tissue extracts confirmed the spectroscopy data and showed that pyruvate inhibits the efflux of adenine nucleotide derivatives. Tissue concentrations of adenosine monophosphate were three times greater and adenosine 50% less after 30 min of ischaemia in the pyruvate perfused group.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Substrate regulation of the nucleotide pool during regional ischaemia and reperfusion in an isolated rat heart preparation: a phosphorus-31 magnetic resonance spectroscopy analysis. 316 43

Left ventricular aneurysm (LVA) remains a poorly understood entity, often resulting in congestive failure that is not consistently improved by standard resection with linear closure. Although other surgical approaches have been proposed, current methods to assess their effect on left ventricular function are not adequate. The purpose of the present study was to quantitatively define regional systolic function in patients with LVA and to assess acute changes in regional function after standard repair. Seven patients underwent resection of an anteroapical LVA. Intraoperative two-dimensional echocardiography was performed off cardiopulmonary bypass immediately before and after resection. In all patients, short-axis views at the papillary muscle (apex) level showed anteroseptal paradox and distorted geometry, whereas at the mitral valve (base), symmetric wall motion and geometry were preserved. Videotaped echo images were divided into octants by a floating axis fitted to internal landmarks. Myocardial area and midwall perimeter were obtained for each octant, and wall thickness was calculated at end diastole (ED), isovolumetric systole (IS), and end systole (ES). Wall thickening (delta t) for each segment was calculated as the percent increase in thickness from ED and averaged for all seven patients. At the apex level before resection, isovolumetric thinning occurred in the aneurysm as well as bordering segments, with delta t ranging from -17 +/- 5% (+/- SEM) in the anteroseptal segment to 12 +/- 6% posterolaterally (p less than 0.05). The isovolumetric bulge was followed by late-systolic thickening, however, with delta t ranging from 13 +/- 7% to 27 +/- 8% (NS).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quantitative analysis of regional systolic function with left ventricular aneurysm. 316 93

Regional diastolic wall motion was studied with sonomicrometry in 30 open chest anaesthetised dogs after left anterior descending stenosis or occlusion. Post-systolic shortening and thickening, defined as the magnitude of segment shortening or wall thickening that occurred after end systole, was measured in peripheral and central ischaemic segments. These post-systolic events developed concurrently with impaired systolic shortening or thickening, either immediately after acute coronary occlusion or during progressive stenosis, and persisted with the development of dyskinesis and during reperfusion. The magnitude of these events in dyskinetic segments of 24 dogs was considerable, reaching 50(2)% (mean(SEM)) and 33(3)% of shortening or thickening that was present before coronary occlusion. Post-systolic shortening and thickening were maximum at 100(2) ms after peak negative dP/dt. Significant correlations were found between systolic shortening or thickening before coronary occlusion and post-systolic shortening (r = 0.74, 56 segments) or thickening (r = 0.84, 19 segments) after occlusion, but there was no correlation between post-systolic shortening or thickening and dyskinetic lengthening or thinning. In seven dogs followed for 4 h after coronary occlusion post-systolic shortening fell by 15% in peripheral segments and by 70% in central segments (p less than 0.002). In 17 dogs reperfused after 60 (n = 9) or 90 (n = 8) min of coronary occlusion the maximal recovery of systolic shortening early after reperfusion was significantly related to the magnitude of post-systolic shortening immediately before reperfusion (60 min occlusion r = 0.84, 90 min occlusion r = 0.88). These data show that post-systolic shortening is a marker of potential for early recovery of function of acutely ischaemic myocardium and suggest that it is due, at least in part, to an active process.
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PMID:Post-systolic shortening: a marker of potential for early recovery of acutely ischaemic myocardium in the dog. 344 Feb 62


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