Certain immunologic substances in the serum of patients with myocardial infarction and other cardiovascular diseases

Serum anti-heart hemagglutinins occurred in 29 per cent of patients with myocardial infarction, as compared to 6 per cent of normal control subjects, had a high prevalence in patients with rheumatic heart disease, occurred in 2 of 5 with a cardiomyopathy, and had a very low frequency in individuals who had noncardiac diseases with or without a vascular component.Serum inhibitors of anti-heart hemagglutinations were found in one half of the patients with myocardial infarction and in those having diseases with vascular involvement, e.g., lupus erythematosus, pulmonary embolism, and syphilitic aortitis. The inhibitors found associated with cardiovascular diseases inhibit at either the antigen or antiserum site during the hemagglutination test, whereas the normal sera which display inhibition do so at both sites, suggesting a lack of anti-heart specificity. From these data it appears that, with the sequential use of both the anti-heart hemagglutination technique and the inhibition test, positive results can be obtained in over one half of the patients with myocardial infarction.As diagnostic adjuncts, these tests still offer only limited assistance in the clinical detection of cardiovascular diseases. A positive anti-heart hemagglutination inhibition test alone appears to be related to less specific vascular damage.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33389/1/0000788.pd

Spatial correlation bias in late-Cenozoic erosion histories derived from thermochronology

International audienceThe potential link between erosion rates at the Earth's surface and changes in global climate has intrigued geoscientists for decades1,2 because such a coupling has implications for the influence of silicate weathering3,4 and organic-carbon burial5 on climate and for the role of Quaternary glaciations in landscape evolution1,6. A global increase in late-Cenozoic erosion rates in response to a cooling, more variable climate has been proposed on the basis of worldwide sedimentation rates7. Other studies have indicated, however, that global erosion rates may have remained steady, suggesting that the reported increases in sediment-accumulation rates are due to preservation biases, depositional hiatuses and varying measurement intervals8-10. More recently, a global compilation of thermochronology data has been used to infer a nearly twofold increase in the erosion rate in mountainous landscapes over late-Cenozoic times6. It has been contended that this result is free of the biases that affect sedimentary records11, although others have argued that it contains biases related to how thermochronological data are averaged12 and to erosion hiatuses in glaciated landscapes13. Here we investigate the 30 locations with reported accelerated erosion during the late Cenozoic6. Our analysis shows that in 23 of these locations, the reported increases are a result of a spatial correlation bias—that is, combining data with disparate exhumation histories, thereby converting spatial erosion-rate variations into temporal increases. In four locations, the increases can be explained by changes in tectonic boundary conditions. In three cases, climatically induced accelerations are recorded, driven by localized glacial valley incision. Our findings suggest that thermochronology data currently have insufficient resolution to assess whether late-Cenozoic climate change affected erosion rates on a global scale. We suggest that a synthesis of local findings that include location-specific information may help to further investigate drivers of global erosion rates

Isozyme profiles and protein patterns in specific organ damage

Serum lactic dehydrogenase isozymes have been utilized as a means of detecting specific organ damage in rats. The serum LDH isozyme patterns seen in response to liver or kidney damage are markedly different, thus these patterns were utilized to identify the damaged organ. Liver damage resulted in increased activity of the serum LDH-5 isozyme while kidney damage produced increased activity of LDH-1 and LDH-2. The ip injection of mercuric chloride (HgCl2) resulted in elevated activity of LDH-1 and LDH-2, characteristic of kidney damage, after doses as low as 2 mg/kg. In a time sequence study following the injection of 4 mg HgCl2/kg body weight, there was an early elevation of LDH-5 suggestive of liver damage. This was followed approximately 12 hours after injection by marked increase of LDH-1 and LDH-2 characteristic of kidney damage. An alteration of the serum protein electrophoretic pattern was also noticed in HgCl2 treated animals. This technique of studying serum isozyme patterns may become a valuable tool in the detection of organ damage produced by toxic compounds.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32792/1/0000165.pd

Geochronological evidence for continuous exhumation through the ductile-brittle transition along a crustal-scale low-angle normal fault (Simplon Fault Zone, Central Alps)

Tectonics, vol. 29, pp. TC3002, 25 pp., 2010International audienceMajor low-angle normal faults juxtapose different structural levels of the crust that record both brittle and ductile deformation. Field relationships alone cannot establish whether these different responses to deformation represent (1) parts of a single process of exhumation along the detachment or (2) two separate events, with the later, more discrete brittle detachment exhuming a fossil ductile shear zone from depth. These two general models are critically assessed for the low-angle normal Simplon Fault Zone (SFZ) in the central Alps. The SFZ shows a spatial transition from a broad ductile mylonitic shear zone to a discrete brittle detachment with identical kinematics. The age of the ductile shear zone and ductile-brittle transition is controversial. We present a detailed geochronological study based on fission track, 40Ar/39Ar, and Rb/Sr microsampling dating, coupled with structural, petrological, and chemical analyses that provides tight constraints on SFZ timing. Discontinuous mineral cooling ages over a broad range of temperatures across the fault zone argue for fault activity between 20 and 3 Ma. On the basis of synkinematic white mica in low-temperature shear zones and necks of foliation boudinage, the brittle-ductile transition in the footwall could be dated at ∼14.5–10 Ma. Overall, the data presented here are consistent with a continuous transition from ductile shearing to a more localized zone of brittle deformation within the same geological framework, over a period of ∼15 Ma. The SFZ is therefore an example of a telescoped crustal section within a single major low-angle fault, involving a continuous period of exhumation rather than a two-stage structure

Worldwide acceleration of mountain erosion under a cooling climate

Climate influences the erosion processes acting at the Earth’s surface. However, the effect of cooling during the Late Cenozoic era, including the onset of Pliocene–Pleistocene Northern Hemisphere glaciation (about two to three million years ago), on global erosion rates remains unclear1, 2, 3, 4. The uncertainty arises mainly from a lack of consensus on the use of the sedimentary record as a proxy for erosion3, 4 and the difficulty of isolating the respective contributions of tectonics and climate to erosion5, 6, 7. Here we compile 18,000 bedrock thermochronometric ages from around the world and use a formal inversion procedure8 to estimate temporal and spatial variations in erosion rates. This allows for the quantification of erosion for the source areas that ultimately produce the sediment record on a timescale of millions of years. We find that mountain erosion rates have increased since about six million years ago and most rapidly since two million years ago. The increase of erosion rates is observed at all latitudes, but is most pronounced in glaciated mountain ranges, indicating that glacial processes played an important part. Because mountains represent a considerable fraction of the global production of sediments9, our results imply an increase in sediment flux at a global scale that coincides closely with enhanced cooling during the Pliocene and Pleistocene epochs10, 11