Large-scale chemoenzymatic synthesis of blood group and tumor-associated poly-N-acetyllactosamine antigens

Poly-N-acetyllactosamines (pLNs) are common terminal sugars of many N- and O-linked glycan structures present in glycoproteins and glycolipids. Utilizing various glycosyltransferases, we developed new and efficient chemoenzymatic methods for the synthesis of pLNs in gram-scale. Specifically, the use of sialyltransferases and fucosyltransferases enabled us to synthesize and purify 24 blood group and tumor-associated pLN derivatives with alpha-(2-->3)- and alpha-(2-->6)-linked sialic acid, as well as with alpha-(1-->2)- and alpha-(1-->3)-linked fucose. All synthesized derivatives were linked to a short 2-azidoethyl spacer for further modification.     

Interpreting an Archaean paleoenvironment through 3D imagery of microbialites

While stromatolites, and to a lesser extent thrombolites, have been extensively studied in order to unravel Precambrian (>539 Ma) biological evolution, studies of clastic-dominated microbially induced sedimentary structures (MISS) are relatively scarce. The lack of a consolidated record of clastic microbialites creates questions about how much (and what) information on depositional and taphonomic settings can be gleaned from these fossils. We used μCT scanning, a non-destructive X-ray-based 3D imaging method, to reconstruct morphologies of ancient MISS and mat textures in two previously described coastal Archaean samples from the ~3.48 Ga Dresser Formation, Pilbara, Western Australia. The aim of this study was to test the ability of μCT scanning to visualize and make 3D measurements that can be used to interpret the biotic–environmental interactions. Fossil MISS including mat laminae with carpet-like textures in one sample and mat rip-up chips in the second sample were investigated. Compiled δ¹³C and δ³⁴S analyses of specimens from the Dresser Fm. are consistent with a taxonomically diverse community that could be capable of forming such MISS. 3D measurements of fossil microbial mat chips indicate significant biostabilization and suggest formation in flow velocities >25 cm s⁻¹. Given the stratigraphic location of these chips in a low-flow lagoonal layer, we conclude that these chips formed due to tidal influence, as these assumed velocities are consistent with recent modeling of Archaean tides. The success of μCT scanning in documenting these microbialite features validates this technique both as a first step analysis for rare samples prior to the use of more destructive techniques and as a valuable tool for gaining insight into microbialite taphonomy.     

ROENTGEN THERAPY OF RHEUMATOID SPONDYLITIS

Based on the pathological processes involved in rheumatoid spondylitis, comparison is made between the physical qualities of certain techniques of roentgen therapy. Graphic representation of the isodose curves and the homogeneous distribution of radiation pertaining to the method herein advocated is shown.Results obtained in the treatment of 125 cases illustrative of the evolution of technique experienced at the University of California Hospital are tabulated. The indications, contraindications, and complications of the method are discussed.Practically every patient with rheumatoid spondylitis, regardless of the stage of the disease, was benefited, with the best results having been obtained when the radiation was given in three courses, separated by rest periods, and homogeneously distributed along the spine.     

HOMEOSTATIC ADJUSTMENTS AFTER EXERCISE : I. ACID-BASE EQUILIBRIUM OF THE BLOOD

The rate at which displacement and recovery of the acid-base equilibrium of the blood occur in young adult males subjected to short periods of maximal exertion has been determined. Displacement of acid-base equilibrium produced by severe exercise is along the fixed acid path, similar to the path of displacement produced by ingestion of acidifying agents such as ammonium chloride. Maximum displacement of the acid-base equilibrium is not reached until 7 to 10 minutes after the cessation of exercise. By this time over 50 per cent of the displacement in oxygen consumption, respiratory volume, and blood pressure have disappeared. A much greater metabolic acidosis was produced by exercise than could be induced by the oral administration of ammonium chloride. Recovery from the metabolic acidosis produced by exercise was much more rapid (10 times) than was recovery from the acidosis produced by ammonium chloride. After exercise the pH, returned to normal values more rapidly than did the bicarbonate content of the serum.     

A PHYSICAL THEORY OF ACID ANION DISPLACEMENT AND RECOVERY FOLLOWING EXERCISE

A simple theoretical model has been presented whose behavior duplicates the variation in bicarbonate ion concentration in the blood following exercise. Methods for the evaluation of the constants of rational equations to describe the concentration in muscle cells, in blood plasma, and in removal cells, of the anions produced in exercise have been devised. These methods have been applied to experimental data from 23 experiments, and a close agreement between the observed and theoretically predicted values for blood plasma has been found. From the mathematical analysis of the data values for permeability of acid anions produced in exercise have been estimated as 75 x 10^–5 and 5.9 x 10^–5 cm. per sec. between muscle cell and blood (extracellular fluid) and between blood plasma and removal cells respectively.     

Oxazine Dyes. Iv. Simultaneous Nuclear and Double-Contrast Cytoplasmic Staining from A Single Solution

A dye mixture, consisting of a celestine blue B dispersion (prepared according to Gray et al. 1956), orange G, and acid fuchsin in one solution, simultaneously stains nuclear elements and gives double contrast staining of cytoplasmic elements. Orange G, 0.16 gm, and acid fuchsin, 0.04 gm, dissolved in 100 ml of celestine blue B dispersion and adjusted to pH 0.8 gives, when applied for 1.5 min, results comparable or superior to other “triple contrast” stains on a wide variety of tissues. No differentiation other than that which occurs during dehydration is necessary.