Renal involvement following near-drowning in the sea

1. The metabolic changes in rats following introduction of sea water directly into the stomach were studied. The results were compared with those of a human case report of acute renal failure following swallowing of sea water. 2. In both rats and man, acute renal failure appeared within the first 24 hr. A slight improvement was found five days later. 3. There was an acute hypocalcemia. This was supposedly due to the large magnesium content of the sea water. 4. It is probable that water entering the alimentary canal, dry drowning, affects the kidneys by the initial flow of water to the intestines. This results in hemo-concentration and reduced kidney function. The abnormality is a transient one and could be due to a partial anoxia due to shrinking of the erythrocytes. 5. It is concluded that an apparently uneventful swallowing of sea water can turn into secondary drowning with transient acute renal failure.     

Analytical and numerical analyses of the micromechanics of soft fibrous connective tissues

State of the art research and treatment of biological tissues require accurate and efficient methods for describing their mechanical properties. Indeed, micromechanics-motivated approaches provide a systematic method for elevating relevant data from the microscopic level to the macroscopic one. In this work, the mechanical responses of hyperelastic tissues with one and two families of collagen fibers are analyzed by application of a new variational estimate accounting for their histology and the behaviors of their constituents. The resulting close-form expressions are used to determine the overall response of the wall of a healthy human coronary artery. To demonstrate the accuracy of the proposed method, these predictions are compared with corresponding 3D finite element simulations of a periodic unit cell of the tissue with two families of fibers. Throughout, the analytical predictions for the highly nonlinear and anisotropic tissue are in agreement with the numerical simulations.     

The divalent cation requirement of Dead Sea halobacteria

Pleomorphic Halobacterium strains isolated from the Dead Sea (H. volcanii, H. marismortui) require high concentrations of divalent cations (75 mM Mg²⁺) for growth. When suspended in medium containing less than 50 mM Mg²⁺ cells lose their native shape within minutes and become spherical. This occurs even at elevated sodium chloride concentrations. Concomitant with the morphological changes, a high mlecular weight component which is positive in Coomassie Brilliant Blue and in periodate Schiff stain is released into the surrounding medium. At divalent cation concentrations lower than 100 mM magnesium cells were shown to lose their viability and their ability to incorporate amino acids. The potency of different divalent cations or their combinations to enable growth and stabilize morphology and viability was studied. It is suggested that different mechanisms underlie the divalent cation requirement of the different functions.     

Comparative metabolic diversity in two solar salterns

The purpose of this study was to compare the metabolic diversity of the whole microbial community in an oligotrophic saltern (Eilat, Israel) and in a saltern with a more enriched source water (Newark, California). Between 1993 and 1998 water samples were taken from selected locations within the solar salterns of the Cargill Solar Salt Plant, Newark, California, and the Israel Salt Co. in Eilat, Israel. To examine the whole community metabolic diversity, we used the 96-well BIOLOG GN^{{ TM}} plates which contain 95 different carbon sources and a control well. Plates from samples containing greater than 15% salt were excluded from the final analyses because of a lack of reproducibility when multiple plates were inoculated with the same sample. The data were analyzed by simple matching coefficient and principal component analysis. Both methods gave similar results. Two major clusters were formed. These could be subdivided into 10 sub-clusters with only three samples from the Newark saltern in December 1997 joining at the 95% similarity level. Most of the inlet and lower salinity samples from the Cargill samples comprised one large subcluster. Several carbon sources were used by 85% of the microbial community from the California samples, while 85% of the Eilat samples had no commonly used carbon sources. These results suggest that ponds in different geographic locations may have communities with different microbial populations despite the similarities in salt content and processing for salt production.     

Raman Spectroscopy of Microbial Pigments

Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions.