Functional evaluation in congenital and acquired heart disease

Conclusions Functional evaluation of the cardiovascular system using rapid imaging (spiral echo planar), chemical shift, and velocity mapping is capable of making the diagnosis in congenital and acquired cardiovascular disease which, between them, cause the largest number of deaths of any disease in the western world and massive morbidity and suffering. Furthermore, for the first time in the history of medicine, there is the opportunity to apply preventive measures to eardicate the epidemic of preventable arterial disease. There needs to be a change of emphasis and a switching of resources to apply to the most common diseases rather than to those which are most easily studied. There also needs to be proper training in cardiovascular MR, not so much for imagers as for cardiologists and experts in vascular disease.     

MR high-resolution imaging of arterial intimal hyperplasia at 1.5 T

Intimal hyperplasia is the earliest microscopic change detectable in the arterial wall in the development of arteriosclerosis and atherosclerosis. To enable high-resolution imaging of this, a standard 1.5-T machine was modified using inserted gradient coils of 30 cm internal diameter and surface radio-frequency coils. Six rabbit aorta specimens with injury-induced intimal hyperplasia and two normal rabbit aorta specimens were imaged using a spin-echo sequence of TE 40. Pixel sizes as small as 20 µ×20 µ could be obtained and the area of intimal hyperplasia could be measured at 80 µ×40 µ. The results were compared with those made by a computer-linked microscope. In the injured aortas, there was a low-signal region on magnetic resonance imaging which corresponded to the media of the vessel wall when compared with the histology.T ₁ andT ₂ constants for the media were determined and compared with those of a normal specimen. TheT ₁ constant was shorter for the media of the injured aorta than in the normal. This could be related to the disruption of the internal elastic lamina and migration of muscle cells to the intima which occurs following injury. The popliteal artery of four normal volunteers was imaged and the area of the wall could be measured at a pixel size of 312 µ×160 µ. This suggests thatin vivo studies of intimal hyperplasia arteriosclerosis and atherosclerosis could be made.     

Assessment of regional left ventricular long-axis motion with MR velocity mapping in healthy subjects

We present a case of trichothiodystrophy associated with a hypereosinophilic syndrome. This case had been followed for 30 years. Trichothiodystrophy was characterized by lamellar ichthyosis, hair and nail dystrophies, kyphoscoliosis, congenital luxation of the hip. The hypereosinophilic syndrome was characterized by an itching urticaria-like eruption. Although the patient's general condition had remaining stable for 30 years, during the last year it worsened and the patient suddenly died. The authors discuss about the significance of this association.     

Redundant and selective roles for erythropoietin receptor tyrosines in erythropoiesis in vivo

Cytokine receptors have been shown in cell culture systems to use phosphotyrosine residues as docking sites for certain signal transduction intermediates. Studies using various cellular backgrounds have yielded conflicting information about the importance of such residues. The present studies were undertaken to determine whether or not tyrosine residues within the erythropoietin receptor (EPOR) are essential for biologic activity during hematopoiesis in vivo. A variant of the EPOR was constructed that contains both a substitution (R129C) causing constitutive receptor activation as well as replacement of all eight cytoplasmic tyrosines by phenylalanines (cEPORYF). A comparison between animals exposed to recombinant retroviruses expressing cEPOR and cEPORYF showed that efficient red blood cell (RBC) development in vivo is dependent on the pressence of tyrosine residues in the cytoplasmic domain of the EPOR. In addition, an inefficient EPOR tyrosine independent pathway supporting RBC development was detected. Tyrosine add-back mutants showed that multiple individual tyrosines have the capacity to restore full erythropoietic potential to the EPOR as determined in whole animals. The analysis of primary erythroid progenitors transduced with the various cEPOR tyrosine mutants and tyrosine add-backs showed that only tyrosine 343 (Y1) and tyrosine 479 (Y8) were capable of supporting immature burst-forming unit-erythroid progenitor development. Thus, this receptor is characterized by striking functional redundancy of tyrosines in a biologically relevant context. However, selective tyrosine residues may be uniquely important for early signals supporting erythroid development.     

Inexpensive in situ time-integrating seawater nutrient sampler

An in situ time-integrating seawater sampler in which air escaping from the sample bottle through a capillary regulates flow of seawater into the sampler is described for determination of average plant nutrient concentration during a 10–50 h period. The sampler collected water at a constant rate which was approximately equal to that predicted from the Hagen-Poiseuille equation. The sampler has advantages over those described previously: it is less susceptible to blockage from suspended particulates in seawater, less expensive, and the seawater collection rate should be less temperature-dependent.     

Processes of overall similarity sorting in free classification.

The processes of overall similarity sorting were investigated in 5 free classification experiments. Experiments 1 and 2 demonstrated that increasing time pressure can reduce the likelihood of overall similarity categorization. Experiment 3 showed that a concurrent load also reduced overall similarity sorting. These findings suggest that overall similarity sorting can be a time-consuming analytic process. Such results appear contrary to the idea that overall similarity is a nonanalytic process (e.g., T. B. Ward, 1983) but are in line with F. N. Milton and A. J. Wills's (2004) dimensional summation hypothesis and with the stochastic sampling assumptions of the extended generalized context model (K. Lamberts, 2000). Experiments 4 and 5 demonstrated that the relationship between stimulus presentation time and overall similarity sorting is nonmonotonic, and the shape of the function is consistent with the idea that the three aforementioned processes operate over different parts of the time course. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fatty acid composition of lipids from the contents of rock lobster (Panulirus cygnus) cephalothorax

The contents of rock lobster cephalothorax were analyzed for lipid content and fatty acid composition. They contain a diversity of saturated (35.5±0.5%), monounsaturated (26.3±1.7%), and polyunsaturated fatty acids, n-3 highly unsaturated fatty acids (11.5±0.5%) among them. The possibility of using these products as a supplement to fish and food animals’ diets is discussed.     

Separation and identification of ximenynic acid isomers in the seed oil ofSantalum spicatum R.Br. as their 4,4-dimethyloxazoline derivatives

The seed oil ofSantalum spicatum contains a significant amount of ximenynic acid,trans-11-octadecen-9-ynoic acid, a long-chain acetylenic fatty acid, as a major component (34%). The identity oftrans-ximenynic acid was confirmed after isolation by ultraviolet, infrared, and nuclear magnetic resonance (NMR) (¹H- and¹³C-) spectroscopy and by gas chromatography/mass spectrometry (GC/MS). Thecis isomer of ximenynic acid was also found (<1%) in some samples. Thecis andtrans isomers were characterized by GC/MS comparison of their methyl esters and 4,4-dimethyloxazoline derivatives.