Role of crush smear cytology in the diagnosis of gastrointestinal malignancy.

Crush smear cytology, commonly used for central nervous system lesions was reported to be useful in the diagnosis of GI malignancies. This study was designed to see the accuracy of crush smear cytology in detection of gastrointestinal malignancy in relation to histopathological examination. First 4 or 5 bits of pinch biopsy specimens from each of the consecutive patients having endoscopic findings suggestive of carcinoma of gastro-intestinal tract were examined by conventional paraffin embedding and H-E staining by a cytologist. Crush smears stained with Papanicolaou's stain were prepared with the last bit of specimen and were examined by another cytologist. The diagnostic accuracy was examined by correlating with clinical and histological data. Out of 100 cases of suspected oesophageal malignancies, 99 were diagnosed as carcinoma by histopathology and 84 (sensitivity 83.83%, accuracy 83%, K - 0.14) cases were positive for malignancy by crush smear cytology. Out of 60 cases of gastric lesion, 54 and 44 cases were proved to be malignant by histopathology (sensitivity 76%, accuracy 73.3%, K - 0.2) and crush smear cytology respectively. Fifty four of the 57 cases of colonic lesions were proved to be malignant by histopathology and 50 (sensitivity 91%, accuracy 89.5%, K - 0.34) were malignant by crush smear cytology. Combining two methods the accuracy was 100%, 95% and 96.5% in detecting oesophageal, gastric and colonic malignancies respectively. Concordance rate of both the methods in diagnosing oesophageal, gastric and colonic lesions were 883.83%, 73.3% and 89.5% respectively. Crush smear cytology is a cheap, easy and rapidly performing technique. The diagnostic yield is very high when the technique is combined with histopathology. It may be used as a useful adjunct to conventional histopathology.

Complexes with truncated RNAs from the large domain of Archaeoglobus fulgidus signal recognition particle.

Protein SRP19 is an important component of the signal recognition particle (SRP) as it promotes assembly of protein SRP54 with SRP RNA and recognizes a tetranucleotide loop. Structural features and RNA binding activities of SRP19 of the hyperthermophilic archaeon Archaeoglobus fulgidus were investigated. An updated alignment of SRP19 sequences predicted three conserved regions and two alpha-helices. With Af-SRP RNA the Af-SRP54 protein assembled into an A. fulgidus SRP which remained intact for many hours. Stable complexes were formed between Af-SRP19 and truncated SRP RNAs, including a 36-residue fragment representing helix 6 of A. fulgidus SRP RNA.

Assembly of archaeal signal recognition particle from recombinant components.

Signal recognition particle (SRP) takes part in protein targeting and secretion in all organisms. Searches for components of archaeal SRP in primary databases and completed genomes indicated that archaea possess only homologs of SRP RNA, and proteins SRP19 and SRP54. A recombinant SRP was assembled from cloned, expressed and purified components of the hyperthermophilic archaeon Archaeoglobus fulgidus. Recombinant Af-SRP54 associated with the signal peptide of bovine pre-prolactin translated in vitro. As in mammalian SRP, Af-SRP54 binding to Af-SRP RNA required protein Af-SRP19, although notable amounts bound in absence of Af-SRP19. Archaeoglobus fulgidus SRP proteins also bound to full-length SRP RNA of the archaeon Methanococcus jannaschii, to eukaryotic human SRP RNA, and to truncated versions which corresponded to the large domain of SRP. Dependence on SRP19 was most pronounced with components from the same species. Reconstitutions with heterologous components revealed a significant potential of human SRP proteins to bind to archaeal SRP RNAs. Surprisingly, M.jannaschii SRP RNA bound to human SRP54M quantitatively in the absence of SRP19. This is the first report of reconstitution of an archaeal SRP from recombinantly expressed purified components. The results highlight structural and functional conservation of SRP assembly between archaea and eucarya.

Biochemical preparation of L-ribose and L-arabinose from ribitol: a new approach.

L-ribose and L-arabinose were prepared biochemically from ribitol via a two-step reaction, by which the complete oxidation of ribitol to L-ribulose (approximately 98%) was achieved by the reaction of washed cells of Acetobacter aceti IFO 3281. The produced L-ribulose was then used as a substrate for the production of L-ribose and L-arabinose. The isomerization of L-ribulose to L-ribose and L-arabinose was carried out using L-ribose isomerase (L-RI) of Acinetobacter sp. strain DL-28 and L-arabinose isomerase (L-AI) of Mycobacterium smegmatis, respectively. At equilibrium, the ratio of L-ribose: L-ribulose was 70:30 and that of L-arabinose: L-ribulose was 90: 10. After a simple purification treatment, both pentoses could be crystallized without the use of column chromatography. The crystals were confirmed as L-ribose and L-arabinose by High-performance liquid chromatography (HPLC), Infrared (IR), Nuclear magnetic resonance (NMR) and optical rotation measurements.

Preparation of L-talose and D-gulose from L-tagatose and D-sorbose, respectively, using immobilized L-rhamnose isomerase.

L-rhamnose isomerase of Pseudomonas sp. LL172 immobilized on BCW 2603 Chitopearl beads was used to produce L-talose and D-gulose. At equilibrium, the production yields of L-talose and D-gulose were determined to be 12 and 10% from L-tagatose and D-sorbose, respectively. The crystallized products were confirmed by HPLC, IR and NMR spectra, and optical rotation measurement analyses.

Production of D-lyxose from D-glucose by microbial and enzymatic reactions.

D-arabitol was first prepared from D-glucose using Candida famata R28. The reaction gave 5.0% D-arabitol from 10.0% D-glucose. D-arabitol was then almost completely converted to D-xylulose using Acetobacter aceti IFO 3281. Finally, D-lyxose was prepared from D-xylulose enzymatically using L-ribose isomerase from toluene-treated cells of Acinetobacter sp. strain DL-28. The isomerization reaction progressed steadily and the concentration of D-xylulose increased from 1.0 to 10.0%. About 70% of D-xylulose was converted to D-lyxose in all cases. Separation of residual D-xylulose from the reaction mixture is very difficult to achieve by column chromatography, but D-xylulose could be selectively degraded easily using Saccharomyces cerevisiae IFO 0841. The product was crystallized and was confirmed to be D-lyxose by HPLC, 13C-NMR spectra, IR spectra analysis, and optical rotation measurement.

Study of hemagglutinating property of enteroinvasive Escherichia coli from various geographical locations.

Thirty-four strains of enteroinvasive Escherichia coli (EIEC) were examined for their ability to agglutinate erythrocytes from different animal species. All strains cultured in Casamino acid-yeast extract medium in the presence of 1 mM CaCl2 at 37 C for 16-22 hr induced maximal expression of hemagglutination (HA) of broad spectrum erythrocytes. The strongest HA was observed with guinea-pig erythrocytes followed by human (O type), rat, mouse, rabbit and sheep erythrocytes. All the strains failed to agglutinate chicken erythrocytes. HA was resistant to D-mannose, D-glucose, D-galactose, L-fucose, and D-fructose. Also HA was resistant to ethylene diamine tetraacetic acid (EDTA) and Na metaperiodic acid, an oxidizing agent. However, it was heat labile and completely inhibited by proteolytic enzymes such as proteinase K and trypsin, suggesting that the possible hemagglutinin of EIEC associated with the cell surface is a proteinaceous substance.