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)

To assess the effects of left ventricular chamber volume on the mechanism of changes in left ventricular developed pressure we performed phosphorous-31 nuclear magnetic resonance spectroscopy, hydrogen-1 nuclear magnetic resonance spectroscopy with a shift reagent, two-dimensional echocardiography, atomic absorption spectrophotometry, microsphere analysis, and surface fluorometry on isovolumic isolated perfused rat hearts with incremental intraventricular balloon volumes, while left ventricular pressure was concurrently monitored. A three-phasic response of developed pressure was noted: 0 to 100 microliters balloon volumes resulted in an increase in developed pressure, whereas developed pressure remained constant at 250 microliters and fell at 400 microliters. Oxygen consumption and [Ca2+]i transients followed the same pattern as developed pressure and coronary flow. Intraventricular volumes of 250 microliters or greater (a volume overload) caused endocardial ischemia, a greater decrease in extracellular versus intracellular water, thinning of the left ventricular free wall, and an increase in chamber size. Mechanical pressure on the tissue, induced by the volume overload, caused ischemia as further evidenced by (1) a negative effect on developed pressure, (2) a decrease in [Ca2+]i transients, (3) a [Ca2+]i overload, (4) a moderate decrease in the phosphorylation potential, and (5) an increase in the oxidation-reduction state (nicotinamide-adenine dinucleotide). The high intracellular calcium associated with volume overload may have been due to both compression and ischemia, which leads to an increased number of cross-bridges in rigor, a high end-diastolic pressure, and an increase in wall stress.
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PMID:Mechanism for depressed cardiac function in left ventricular volume overload. 199 Jul 59

Twelve knees with a range of severity of knee osteoarthritis were assessed by magnetic resonance imaging (MRI) and technetium-99m labelled hydroxymethylene diphosphonate scintigraphy. Five magnetic resonance pulse sequences were evaluated. Proton density (TR = 1000, TE = 26 ms) and STIR (TR = 1500, TI = 100, TE = 30 ms) were chosen for further use. Abnormalities shown by MRI included joint effusions, meniscal disruption, hyaline cartilage thinning, subchondral signal changes, pseudocysts, and heterogeneity of signal from osteophytes. Certain MRI and scintigraphic appearances correlated: (a) 'hyperintense osteophytosis' and ipsilateral 'tramline' scintigraphic uptake, suggesting increased fat content in 'active' osteophytes; (b) subchondral signal change and 'extended' pattern, possibly reflecting inflammation, synovial leak, or fibrovascular repair; (c) patellofemoral joint signal changes and patellar isotope uptake.
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PMID:Magnetic resonance imaging in osteoarthritis of the knee: correlation with radiographic and scintigraphic findings. 199 61

The purpose of this study was to determine the changes in cardiac interstitial fluid (ISF) purine metabolites during 90 min of regional myocardial ischemia. To collect ISF metabolites and measure local coronary blood flow (CBF), cardiac microdialysis probes were implanted into the left anterior descending artery (LAD) and left circumflex artery (LC) perfused myocardium of chloralose-urethane anesthetized dogs (n = 7). Regional ventricular wall thickness was measured in the LAD and LC perfused regions with sonomicrometric crystals, using systolic wall thickening (SWT) as an index of regional ventricular function. Regional myocardial ischemia, produced by occlusion of the LAD, resulted in a decrease in CBF (hydrogen clearance) from 77.3 +/- 12.4 to 10.9 +/- 4.4 ml/min/100 g (P less than 0.05), and systolic wall thinning (control SWT = 15.5 +/- 2.2%; ischemic SWT = -6.8 +/- 1.7%). ISF adenosine was transiently elevated in the ischemic region, obtaining a maximum sixfold increase after 15 min of ischemia. Inosine, hypoxanthine, and to a lesser extent xanthine, composed the majority of metabolites which accumulated in the ISF of the ischemic region, accounting for greater than 95% of the total purine metabolites in the ISF after 20 min of ischemia. Despite the marked increase in ISF inosine, hypoxanthine, and xanthine levels, ISF uric acid levels did not increase in the ischemic region. Although CBF and SWT did not change in the nonischemic LC perfused area, there were small transient increases (two- to fourfold) in ISF adenosine, inosine, and hypoxanthine levels. In summary, these data demonstrate that purine metabolites accumulate rapidly in the ISF during myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interstitial purine metabolites during regional myocardial ischemia. 235 25

Previous study has shown that niridazole (NDZ) is dysmorphogenic to rat embryos between days 10 and 11 under culture conditions including 5% oxygen. Other studies have found that reductive embryonic biotransformation is required but that covalent binding is not a major basis of this embryotoxicity. In research presented here, NDZ exposure of homogenates prepared from day 10 rat embryos resulted in stimulation of oxygen uptake from incubation media. Further studies showed that a large percentage of this increased oxygen uptake was associated with the generation of superoxide anion radical and hydrogen peroxide. These findings led us to hypothesize that redox cycling forms the basis of the in vitro dysmorphogenicity of NDZ. The basic premise of this hypothesis is that as a result of redox cycling, oxygen is depleted from the sensitive tissues of embryos. In order to investigate it, we devised a technique for carefully controlling and monitoring oxygen tensions in embryo cultures. We found that when oxygen concentrations of 4% were established, a highly significant incidence of asymmetric defects resulted. These defects appeared analogous to those induced by NDZ exposure, consisting of asymmetric necrosis of mesenchymal tissue near the cephalic end of the neural tube and thinning of the neuroepithelium on the right. We concluded that the hypoxia induced by redox cycling of NDZ and related nitroheterocycles represents a major embryotoxic principle of action.
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PMID:Studies of embryotoxic mechanisms of niridazole: evidence that oxygen depletion plays a role in dysmorphogenicity. 254 96

Proton NMR imaging of myocardial ischemia without infarction requires the use of paramagnetic contrast agents. Even during the first few hours of infarction, imaging without contrast enhancement reveals only slight natural image contrast. Myocardial infarction, however, is much more readily detected during the first few days and weeks post coronary occlusion; this is due to a marked elevation in T2 during this time period. Chronic infarction, several months after the acute event, does not demonstrate altered signal intensity, but can be detected by visualizing myocardial wall thinning and aneurysm formation. Information regarding high energy phosphate metabolism can be acquired in vivo in ischemic animal preparations; preliminary data has demonstrated that it is possible to acquire similar information noninvasively in man. Development of this technique will eventually permit the study of pharmacological and mechanical interventions aimed at preserving myocardium in the ischemic heart. Exogenous labelling of myocardial tissue with carbon-13 permits the study of the effects of substrates on cellular metabolism. Ultimately, the technique of chemical shift imaging will provide a method of spatially resolving valuable metabolic information in the form of an NMR image. Eventually, with the gradual development of NMR technology, imaging and spectroscopy will become truly important clinical tools in the investigation of ischemic heart disease in man.
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PMID:Evaluation of myocardial ischemia and infarction by nuclear magnetic resonance techniques. 328 14

Nuclear magnetic resonance imaging has emerged in the past few years as a completely noninvasive method for medical imaging of internal organs. Because of the loss of signal intensity by motional nuclei (hydrogen) using most proton imaging techniques, flowing blood within the cardiovascular system generates little or no signal and consequently there is high natural contrast between blood and the walls of blood vessels or cardiac chambers. However, motion during imaging also complicates cardiac imaging because signal is lost from the nuclei in the moving cardiac structures. Consequently electrocardiographic gating of data acquisition is required for nuclear magnetic resonance imaging of the heart. Distinct advantages of nuclear magnetic resonance imaging in relation to other imaging modalities are good contrast between soft tissues and the capability for characterization of specific tissues by estimation of magnetic relaxation times. Early in vitro studies measuring relaxation times of myocardial tissue samples of excised hearts indicate that nuclear magnetic resonance imaging will be capable of discriminating infarcted from normal myocardium. Recent studies using electrocardiographically gated nuclear magnetic resonance imaging of dogs with acute infarction showed the infarct as a region of high intensity on spin-echo images. Initial clinical experience with electrocardiographically gated nuclear magnetic resonance imaging (0.35 tesla) in patients has clearly defined internal cardiac anatomy without the use of contrast media. This technique has demonstrated the consequence of previous myocardial infarction such as regional wall thinning, aneurysm, thrombus and contractile dysfunction, a number of pericardial abnormalities and the morphology of hypertrophic and congestive cardiomyopathies.
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PMID:Assessment of cardiac anatomy using nuclear magnetic resonance imaging. 396 36

Axial magnetic resonance (MR) imaging of the patellofemoral compartment was performed in 75 patients with arthroscopic correlation. Proton density and T2(2500/20/80) weighted images were obtained in all patients. Chondromalacia in stages I and II could not be reliably identified with MR imaging. For the evaluation of stage III and IV chondromalacia, the accuracy of MR was 89%. Focal or diffuse areas of increased or decreased signal alterations of the hyaline cartilage without a contour deformity or cartilaginous thinning do not correlate reliably with arthroscopic staging of chondromalacia. A normal signal intensity is no assurance that softening of the cartilage is not present. The most reliable indicators of chondromalacia are focal contour irregularities of the hyaline cartilage and/or thinning of the hyaline cartilage associated with high signal intensity changes within frank defects or contour irregularities with T2-weighted images. The poor MR-arthroscopic correlation in earlier stages of chondromalacia may be due in part to the subjective basis of the arthroscopic diagnosis. In conclusion, stage I and II chondromalacia of the patellofemoral compartment cannot be reliably evaluated with MR imaging. Stage III and IV chondromalacia is reliably evaluated with MR using the combination of proton density and T2-weighted images.
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PMID:Evaluation of chondromalacia of the patellofemoral compartment with axial magnetic resonance imaging. 837 60

The Ohio State University (OSU) and the Cleveland Clinic Foundation (CCF) developed a 6 x 18 inch low velocity Rheologic Research Tunnel to do flow visualization and other experimental fluid studies, particularly on scaled-up models of cardiovascular devices, such as the CCF's Innovative Ventricular Assist System. The large test section (TS) permits detailed data to be obtained that would be inaccessible with a smaller test prototype. A particular feature of the OSU-CCF program is the use of a non-Newtonian blood analog (NNBA), so the effect of the shear-thinning behavior of blood on the local development of separation, stagnation, and flow patterns can be studied. The TS can simulate a pressure driven slit flow of 6 x 18 in., or the external flow around a vane or blade having an aspect ratio of 1. Maximum pressure is 8.5 psig, while the maximum velocity is 21.7 in/sec. The fluid supply tank has a capacity of 500 gal of NNBA and, with its associated filtration and circulation systems, can be adapted to studies of large transparent models better studied outside the TS. Using 2 pumps, flow rates of 98-610 gal/min can be provided. Instrumentation includes thermistors, a 48 port pressure scanner with pressure transducers, a data acquisition system, and a digital video camera. Dye and hydrogen bubble systems have been developed. Development of such a facility presents problems not encountered in more typical water tables or wind tunnels. These include fundamental issues such as providing a uniform flowfield; practical issues with respect to priming, operating, and obtaining data from the system; and safety considerations. For the very large volume of NNBA, a xanthan gum solution is used, whose shear-thinning behavior depends not only on concentration, but also on age and prior shear history. The lessons learned are presented, permitting others to efficiently develop systems suitable to their testing needs.
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PMID:Development of a 6 x 18 inch rheology tunnel for experimental fluid dynamics investigation. 936 Jan 20

Molecular dynamics trajectories of melittin in an explicit dimyristoyl phosphatidylcholine (DMPC) bilayer are generated to study the details of lipid-protein interactions at the microscopic level. Melittin, a small amphipathic peptide found in bee venom, is known to have a pronounced effect on the lysis of membranes. The peptide is initially set parallel to the membrane-solution interfacial region in an alpha-helical conformation with unprotonated N-terminus. Solid-state nuclear magnetic resonance (NMR) and polarized attenuated total internal reflectance Fourier transform infrared (PATIR-FTIR) properties of melittin are calculated from the trajectory to characterize the orientation of the peptide relative to the bilayer. The residue Lys7 located in the hydrophobic moiety of the helix and residues Lys23, Arg24, Gln25, and Gln26 at the C-terminus hydrophilic form hydrogen bonds with water molecules and with the ester carbonyl groups of the lipids, suggesting their important contribution to the stability of the helix in the bilayer. Lipid acyl chains are closely packed around melittin, contributing to the stable association with the membrane. Calculated density profiles and order parameters of the lipid acyl chains averaged over the molecular dynamics trajectory indicate that melittin has effects on both layers of the membrane. The presence of melittin in the upper layer causes a local thinning of the bilayer that favors the penetration of water through the lower layer. The energetic factors involved in the association of melittin at the membrane surface are characterized using an implicit mean-field model in which the membrane and the surrounding solvent are represented as structureless continuum dielectric material. The results obtained by solving the Poisson-Bolztmann equation numerically are in qualitative agreement with the detailed dynamics. The influence of the protonation state of the N-terminus of melittin is examined. After 600 ps, the N-terminus of melittin is protonated and the trajectory is continued for 400 ps, which leads to an important penetration of water molecules into the bilayer. These observations provide insights into how melittin interacts with membranes and the mechanism by which it enhances their lysis.
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PMID:Molecular dynamics simulation of melittin in a dimyristoylphosphatidylcholine bilayer membrane. 974 4

Pyometra is the accumulation of pus in the uterine cavity, thus stretching its walls and thinning and enlarging the uterus. This change is characteristic of the senium period of life, when the uterus is atrophic with a stenotic cervical canal. It most frequently occurs as a result of secondary infection of the cancerogenic tissue of the uterus and additional stenosation and clogging up of cervical canal by a malignant process. Apart from carcinomas of the body and uterus cervix, pyometra less often can occur in other illnesses such as senile endometritis and senile colpitis. As pyometra most frequently occurs in uterine carcinomas, in detection of this state, we must think of malignancy and direct our examination to this direction. In this paper we present a patient in whom pyometra developed because she carried an intrauterine device for forty years that resulted in chronic endometritis. The main symptoms for which the patient was admitted to hospital were abdominal pain and intensive suppurative vaginal excretion a month after removal of intrauterine device. The diagnosis of pyometra was made by gynaecological and ultrasound examinations, and also on the basis of gynaecological and ultrasound examinations one month after chronic endometritis was confirmed. On the basis of this finding we suspected that chronic endometritis was caused by this state. By cytological, PAP and histopathological examinations of samples obtained by explorative curettage and biopsy of the uterine cervix, malignant changes were eliminated a possible cause. By laboratory analysis and bacteriological examination of the uterine cavity and vaginal excretion, inflammatory changes of the uterine mocous membrane were confirmed as a cause of the pyometra. This conditions was due to carrying the intrauterine device for more decades. The therapy consisted of dilatation of the cervical canal and evacuation of accumulated suppurative contents and irrigation of uterine cavity with 3% solution of hydrogen peroxide and Povidon. Also wide spectrum antibiotics and uterotonics were given. Such treatment contributed to a fast and effectious recovery.
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PMID:[Pyometra as a result of placement of an intrauterine device for 40 years and chronic endometritis]. 1275 Nov 68


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