Acute poststreptococcal glomerulonephritis mimicking Henoch-Sch?nlein purpura

Two children with acute glomerulonephritis, cutaneous vasculitis, and abdominal pain are reported. One child also had transient arthralgia and gastrointestinal hemorrhage. Although the clinical presentation mimicked many of the features of Henoch-Sch?nlein purpura, both patients had unusual variants of poststreptococcal glomerulonephritis.     

Growth of clinical isolates of anaerobic bacteria on agar media: effects of media composition, storage conditions, and reduction under anaerobic conditions

The quantitative growth, the colony size, and the rate of growth of 47 clinical anaerobic isolates were compared on five different media, namely Brucella agar, brain heart infusion agar, Columbia agar, Schaedler agar, and tryptic soy agar. There was no significant difference in the quantitative growth of the anaerobes inoculated onto the five media. Although no single medium was superior for the growth of all isolates, 12 of 22 isolates, inoculated onto media stored for 4 weeks or less, grew best on Schaedler agar. The effects of supplementation of the media with reducing agents and reduction of the media before use were also analyzed and were found to be affected by the composition and length of storage of the media, as well as the bacteria tested.     

Selective analysis for adenosine using reversed-phase high-pressure liquid chromatography

A high-pressure liquid chromatographic procedure for the selective determination of adenosine in the presence of other nucleic acid components is reported. Reversed-phase microparticle columns and an isocratic elution mode of dilute potassium dihydrophosphate and anhydrous methanol were used. The analysis is specific for adenosine and is achieved in less than 10 min. An example of the use of this analysis in a biomedical study is reported.     

In vivo determination of RNA structure-function relationships: analysis of the 790 loop in ribosomal RNA

The 790 loop is a conserved hairpin located between positions 786 and 796 of Escherichia coli 16 S rRNA that is required for ribosome function. Using a novel genetic approach, all positions in the loop were simultaneously mutated and functional mutant sequences were selected in vivo. This "instant evolution" experiment revealed that approximately 190 of the 262,144 possible mutant sequences were functional. Analysis of functional mutant sequences allowed discrimination between nucleotides directly involved in protein synthesis and those involved primarily in loop structure. Among the functional mutant sequences, positions 789 and 791 were invariant and extensive covariation was observed among the nucleotides at the base of the loop at positions 787, 788, 794 and 795. NMR and thermodynamic analyses of model 790 hairpins in vitro revealed weak pairing interactions between positions 787 and 795 and between positions 788 and 794 consistent with the in vivo mutational analysis. Functional analysis of site-directed mutants containing all possible nucleotide combinations at positions 787 and 795 in vivo showed that stable base-pairs at these positions prevent subunit association.     

Proteinase activity in the isolates of Trichomonas vaginalis according to their pathogenicity

Ten axenic isolates of Trichomonas vaginalis were subcutaneously injected to the BALB/c mice in order to assess their pathogenicity by means of so-called "mouse assay" method. All the isolates revealed neutral and acid proteinase activities both in their lysates and in culture media, but the specific activities of both proteinases in the severely pathogenic group were significantly higher than the mildly pathogenic group (p < 0.05). In the SDS-PAGE system in which the electrophoretic gels contained 0.4% gelatin as the substrate, five different banding patterns of trichomonal proteinases were detected, and the patterns were closely related with the pathogenicity of the isolates of T. vaginalis. All five bands might be regarded as cysteine proteinases group in the inhibitor assays. The cytotoxicity of the lysates of T. vaginalis to the target Chinese hamster ovarian (CHO) cell line was also significantly different according to the pathogenicity of the isolates, and generally lower in the lysates treated with cysteine proteinase inhibitors than in the control lysates. In summarizing the results, it might be considered that the proteinases of T. vaginalis showing five electrophoretic banding patterns are closely related with the pathogenicity and cytotoxicity of the isolates of T. vaginalis.     

Polarity of axoplasmic microtubules in the olfactory nerve of the frog

Pieces of olfactory nerve of the bullfrog were extracted in a tubulin assembly buffer medium containing detergents. With incubation at 37 degrees C in such medium containing soluble tubulin, ribbons of protofilaments are formed on the surfaces of microtubules, with the ribbons curving in a clockwise or counterclockwise direction. The direction of hooking reflects the polarity of the microtubule. In nerve pieces oriented such that cross sections could be viewed toward the perikarya of the axons, over 90% of the ribbons on microtubules showed a clockwise orientation. When observers were looking toward the axonal terminals, most ribbons on microtubules showed a counterclockwise direction. In single axons in which ribbons appeared on all the contained microtubules, the ribbons showed a single directionality. The evidence suggests that microtubules in axons have a single polarity, probably reflecting their assembly from the perikarya outward through the axoplasm. If bidirectional transport is assumed in these axons, it is not reflected by the polarity of their microtubules, which may mean that the directionality of transport is provided by components other than microtubules.