Prognosis in giant-cell arteritis.

In a study to assess the natural history of giant-cell arteritis, 90 patients with proved disease were followed up from the time of diagnosis. Early mortality was low and most commonly due to vertebral arteritis, but cerebral infarction did not appear to be a late complication. High maintenance dose steroids and visual loss were associated significantly with a shortened life span (p=0.0003 and p=0.0024). One-third of the patients developed chronic relapsing disease, but serious late complications were not encountered. After the initial attack has been controlled steroid dosage should be reduced to the minimum needed to alleviate symptoms.     

On the three-dimensional structure and catalytic mechanism of triose phosphate isomerase

Triose phosphate isomerase is a dimeric enzyme of molecular mass 56 000 which catalyses the interconversion of dihydroxyacetone phosphate (DHAP) and D-glyceraldehyde-3-phosphate. The crystal structure of the enzyme from chicken muscle has been determined at a resolution of 2.5 A, and an independent determination of the structure of the yeast enzyme has just been completed at 3 A resolution. The conformation of the polypeptide chain is essentially identical in the two structures, and consists of an inner cylinder of eight strands of parallel beta-pleated sheet, with mostly helical segments connecting each strand. The active site is a pocket containing glutamic acid 165, which is believed to act as a base in the reaction. Crystallographic studies of the binding of DHAP to both the chicken and the yeast enzymes reveal a common mode of binding and suggest a mechanisms for catalysis involving polarization of the substrate carbonyl group.     

Correlations among leaf CO2-exchange rates,areas and enzyme activities among soybean cultivars

Soybean (Glycine max (L.) Merr.) genotypes varying in area per nodal unit (usually a trifoliolate) and maturity class were grown in plots at the University of Illinois experimental farm. Leaf CO₂-exchange rates per unit area (CER) were measured under sunlight on intact plants. In addition to previously reported correlations with specific leaf weight and chlorophyll, CER was positively correlated with ribulose bisphosphate carboxylase (RuBPcase) activity, specific activity, and soluble protein, and was negatively correlated with area per leaf unit. The CER: chlorophyll correlation was destroyed by high CER values in 2 chlorophyll-deficient lines. CER values for 27 of the 35 lines tested fell within the range of those for isolines of cultivar Clark varying in leaf characteristics. The CER values were highest for fully expanded leaves during rapid pod fill. These results suggested that photoperiod (maturity) genes and genes for leaf area growth interact with genes controlling photosynthetic CO₂-exchange to produce the major differences in CER values among soybean genotypes.     

Analysis of urine sediments after kidney transplantation

We applied multiparameter flow cytometry for the first time to the classification of cells and particles of urine sediments after kidney transplantation. After fluorescent staining with acridine orange, cells and particles were checked for their size and their peak intensity of green and red fluorescences, known to be related to the amounts of intracellular DNA and intracellular RNA, respectively. Urine sediments were tested daily during a period of up to three weeks. Occurrence and disappearance of certain classes of cells and particles were found to be similar among different patients during normal healing. The results from patients without rejection of the graft are suggested as baseline data, differences from which should be detectable with high sensitivity due to the large number of cells being examined.     

Evolution of the Hong Kong influenza A sub-type. Structural relationships between the haemagglutinin from A/duck/Ukraine/1/63 (Hav 7) and the Hong Kong (H3) haemagglutinins.

The relationship between the haemagglutinin from the influenza virus A/duck/Ukraine/1/63 (Hav 7) and the human Hong Kong variants (H3) has been investigated. Amino-acid-sequence analysis shows that the Hav 7 haemagglutinin closely resembles the 1968 human H3 haemagglutinin in structure. However, the number of amino-acid-sequence differences (23) suggest that the Hong Kong haemagglutinin gene did not come directly from A/duck/Ukraine/1/63 but from a virus derived from it by antigenic drift during the period 1963-1968.     

A Simplified Method for Staining Mast Cells with Astra Blue

The copper phthalocyanin dye astra blue has been used to stain differentially mast cells of the intestine; however, the procedure has not been used widely because of the difficulty in preparing and using the dye solution. Described here is a simple, reliable, and consistent method for selectively staining mast cells using a dye solution that may be prepared in any laboratory without the aid of sophisticated pH metering equipment. Astra blue is mixed with an alcoholic solution containing MgCl₂ · 6H₂O and the pH indicator pararosaniline hydrochloride. Concentrated hydrochloric acid is added dropwise, changing the dye mixture from purple to violet and then to blue. In this low range the weakly ionizing ethanol provides a more stable hydrogen ion concentration than the corresponding aqueous solutions used previously. Alcoholic acid fuchsin is a convenient counterstain, and this simple procedure then provides good contrast between the blue staining mast cell granules and the red tissue background.