With a system in turmoil,will there be enough blood?

In a short time Canadians won''t be able to recognize their blood-collection system. With the Red Cross getting out of the blood business and the government and business moving in, what will the changes mean for Canadians and their physicians?     

Induced CD provides evidence for helical solution conformation in cellulosic chains

Evidence for a helical contribution to the conformation of methylcellulose in dilute solution is given by CD measurements. Congo red binds to methylcellulose in dilute aqueous solution and becomes optically active. The shape of the induced CD spectra is as predicted by exciton coupling for a helical arrangement of chromophores. The magnitude of the induced CD changes reversibly with temperature, decreasing upon heating. The dimer analogue of the polymer, prepared by acid methanolysis, does not show this effect. These observations suggest that the induced optical activity reflects the conformational dissymmetry of the polymer. Analogous experiments with the cellulose oligomers (cellotriose through cellohexaose) show that five anhydroglucose units are necessary before asymmetry is induced upon dye binding.     

Pneumatosis cystoides gastrica associated with adenocarcinoma of the stomach

This paper reports the finding of benign foreign-body-type multinucleated giant cells and clumps of adenocarcinoma cells in gastric brushing cytology specimens of a case confirmed by radiology and histology as pneumatosis cystoides gastrica associated with an ulcerated carcinoma. Pneumatosis cystoides gastrica should be included in the differential diagnosis of benign multinucleated giant cells found in gastric cytology smears.     

Picric acid methods greatly overestimate serum creatinine in mice: more accurate results with high-performance liquid chromatography

The creatinine levels of blood and urine from humans, rats, and mice were measured by high-performance liquid chromatography. These were compared to the alkaline picrate analysis of creatinine performed by standard colorimetric, kinetic, and AutoAnalyzer techniques. For human serum and urine the values obtained using the HPLC technique gave good agreement with four out of five alkaline picrate techniques. For black or white mice, the serum creatinine concentration was 8.7 +/- 0.4 microM by HPLC but 44.9 +/- 1.9 microM by the lowest alkaline picrate method. Mouse urine creatinine concentrations were 3.24 +/- 0.19 mM by HPLC and 4.59 +/- 0.39 mM by the nearest alkaline picrate method. Rat serum creatinine concentrations analyzed by HPLC were about half the values obtained by AutoAnalyzer. Mouse and rat samples seemed to have substances which gave nonspecific color and thus interfered with the analysis of creatinine by the alkaline picrate methods. While the alkaline picrate analysis of creatinine was adequate for human samples, it was necessary to use HPLC to accurately measure rodent creatinine. The fractional excretion of creatinine was determined by measuring creatinine in mouse urine and plasma by both the kinetic and HPLC methods and comparing these values to urine and plasma inulin. Using the kinetic method, creatinine was cleared at 43 +/- 3% of the rate of inulin. Using the HPLC method, creatinine was cleared at 170 +/- 11% of the rate of inulin.     

Toward an identification of mechanical parameters initiating periosteal remodeling: a combined experimental and analytic approach

The ability of bone to adapt to its mechanical environment is well recognized, although the specific mechanical parameters initiating or maintaining the adaptive responses have yet to be identified. Recently introduced mathematical models offer the potential to aid in the identification of such parameters, although these models have not been well validated experimentally or clinically. We formulated a complementary experimental/analytic approach, using an animal model with a well-controlled mechanical environment combined with finite element modeling (FEM). We selected the functionally isolated turkey ulna, since the loading could be completely characterized and the periosteal adaptive responses subsequently monitored and quantified after four and eight weeks of loading. Known loads input into a three-dimensional, linearly elastic FEM of the ulna then permitted full-field mechanical characterization of the ulna. The FEM was validated against a normal strain-gaged turkey ulna, loaded in vivo in an identical fashion to the experimental ulnae. Twenty-four candidate mechanical parameters were then compared to the quantified adaptive responses, using statistical techniques. The data supported strain energy density, longitudinal shear stress, and tensile principal stress/strain as the mechanical parameters most likely related to the initiation of the remodeling response. Model predictions can now suggest new experiments, against which the predictions can be supported or falsified.     

Apical hyphal extension in Streptomyces coelicolor A3(2).

Hyphal extension in the filamentous actinomycete Streptomyces coelicolor A3(2) was shown to occur by addition of newly synthesized wall material in an apical extension zone. Incubation of mycelia with tritiated N-acetyl-D-glucosamine (GlcNAc), a precursor of peptidoglycan, resulted in localized incorporation of label at the apex, as indicated by light microscopic and electron microscopic autoradiography. Within the hyphal extension zone there was a sharp decrease in incorporation with increasing distance from the apex. Hyphal tip shape, examined by low-temperature scanning electron microscopy, approximated to a semi-ellipsoid of revolution and was not hemispherical. Tip shape could be represented accurately by polynomial equations of degree less than seven. The surface stress theory was successfully applied to hyphal tip growth, with tip shape related qualitatively to the inverse of surface tension within the wall of the extension zone. Surface tension was assumed to be inversely proportional to the rate of incorporation of tritiated GlcNAc. Treatment of surface-grown hyphae with beta-lactam antibiotics resulted in localized swelling of hyphal tips. Lysozyme caused swelling of tips and of other regions of hyphae, frequently giving a beaded morphology associated with septa.     

Sixteen discrete RNA components in the cytoplasmic ribosome of Euglena gracilis

We have isolated cytoplasmic ribosomes from Euglena gracilis and characterized the RNA components of these particles. We show here that instead of the four rRNAs (17-19 S, 25-28 S, 5.8 S and 5 S) found in typical eukaryotic ribosomes, Euglena cytoplasmic ribosomes contain 16 RNA components. Three of these Euglena rRNAs are the structural equivalents of the 17-19 S, 5.8 S and 5 S rRNAs of other eukaryotes. However, the equivalent of 25-28 S rRNA is found in Euglena as 13 separate RNA species. We demonstrate that together with 5 S and 5.8 S rRNA, these 13 RNAs are all components of the large ribosomal subunit, while a 19 S RNA is the sole RNA component of the small ribosomal subunit. Two of the 13 pieces of 25-28 S rRNA are not tightly bound to the large ribosomal subunit and are released at low (0 to 0.1 mM) magnesium ion concentrations. We present here the complete primary sequences of each of the 14 RNA components (including 5.8 S rRNA) of Euglena large subunit rRNA. Sequence comparisons and secondary structure modeling indicate that these 14 RNAs exist as a non-covalent network that together must perform the functions attributed to the covalently continuous, high molecular weight, large subunit rRNA from other systems.