(1S,3R)-N-{(3S,10S,12S,13R,17R)-12-Hy-droxy-17-[(R)-5-hy-droxy-pentan-2-yl]-10,13-di-methyl-hexa-deca-hydro-1H-cyclo-penta-[a]phenanthren-3-yl}adamantane-1-carboxamide 0.25-hydrate.

The title compound, C35H57NO3·0.25H2O, was synthesized from de-oxy-cholic acid followed by a protection, a Mitsonobu substitution, a Staudinger reduction, formation of an amide and final reduction in the lateral chain. The compound crystallizes in the P1 space group with four steroid mol-ecules and one water mol-ecule in the triclinic cell unit. The crystal structure features O-H⋯O hydrogen bonding. The crystal studied was refined as a non-merohedral twin.

[Haemorrhagic posterior reversible encephalopathy syndrome and COVID-19]. / Síndrome de encefalopatía posterior reversible hemorrágica y COVID-19.

TITLE: Síndrome de encefalopatía posterior reversible hemorrágica y COVID-19.

A dual-specific Glu-tRNA(Gln) and Asp-tRNA(Asn) amidotransferase is involved in decoding glutamine and asparagine codons in Acidithiobacillus ferrooxidans.

The gatC, gatA and gatB genes encoding the three subunits of glutamyl-tRNA(Gln) amidotransferase from Acidithiobacillus ferrooxidans, an acidophilic bacterium used in bioleaching of minerals, have been cloned and expressed in Escherichia coli. As in Bacillus subtilis the three gat genes are organized in an operon-like structure in A. ferrooxidans. The heterologously overexpressed enzyme converts Glu-tRNA(Gln) to Gln-tRNA(Gln) and Asp-tRNA(Asn) to Asn-tRNA(Asn). Biochemical analysis revealed that neither glutaminyl-tRNA synthetase nor asparaginyl-tRNA synthetase is present in A. ferrooxidans, but that glutamyl-tRNA synthetase and aspartyl-tRNA synthetase enzymes are present in the organism. These data suggest that the transamidation pathway is responsible for the formation of Gln-tRNA and Asn-tRNA in A. ferrooxidans.

Conserved amino acids near the carboxy terminus of bacterial tyrosyl-tRNA synthetase are involved in tRNA and Tyr-AMP binding.

Bacterial tyrosyl-tRNA synthetases occur in two large subfamilies, TyrRS and TyrRZ, that possess about 25% amino acid identity. Their amino-terminal region, the active site domain, is more conserved (>36% identity). The carboxy-terminal segment of these enzymes includes the tRNA binding domain and contains only few conserved residues. Replacement of three of these residues in Acidithiobacillus ferrooxidans TyrRZ revealed that S356 and K395 play roles in tRNA binding, while H306, a residue at the junction of the catalytic and tRNA binding domains, stabilizes the Tyr-AMP:TyrRZ complex. The replacement data suggest that conserved amino acids in A. ferrooxidans TyrRZ and Bacillus stearothermophilus TyrRS play equivalent roles in enzyme function.

Multicenter evaluation of antimicrobial resistance to six broad-spectrum beta-lactams in Colombia: comparison of data from 1997 and 1998 using the Etest method. The Colombian Antimicrobial Resistance Study Group.

The minimum inhibitory concentrations of six broad-spectrum beta-lactam antimicrobial agents were determined in 1998 by use of the Etest versus a total of 823 bacteria in 11 Colombian hospital laboratories. These data were compared with results of a similar study conducted in 1997. The organisms tested included 532 recent clinical isolates of Enterobacteriaceae, 108 Pseudomonas aeruginosa, 94 Acinetobacter species, and 89 oxacillin-susceptible Staphylococcus aureus. Extended-spectrum beta-lactamase production was noted among 27.8 to 33.9% of Escherichia coli isolates and 41.7 to 46.7% of Klebsiella spp. isolates. Hyperproduction of Amp C cephalosporinases was observed with 10.5 to 31.4% of isolates of Enterobacter spp., Serratia spp., and Citrobacter spp. An increase in resistance to all of the beta-lactams was observed among Enterobacteriaceae, Acinetobacter spp. and P. aeruginosa when 1998 results were compared with those obtained in 1997. The overall rank order of activity of the six beta-lactams tested in 1998 versus all clinical isolates was imipenem (93.2% susceptible) > cefoperazone/sulbactam (84.1%) > cefepime (80.9%) > ceftazidime (70.7%) > aztreonam (65.7%) > cefotaxime (65.6%). In contrast, the rank order of these same agents tested against a similar collection of Colombian isolates in 1997 was imipenem (96.6% susceptible) > cefepime (93.6%) > cefoperazone/sulbactam (90.5%) > cefotaxime (74.9%) > aztreonam (74.3%) > ceftazidime (73.2%).

Multicenter evaluation of antimicrobial resistance to six broad-spectrum beta-lactams in Colombia using the Etest method. The Colombian Antimicrobial Resistance Study Group.

The need for comprehensive and quantitative accurate antimicrobial resistance surveillance systems has become acute as a guide to problem recognition and to focus local interventions. A multilaboratory (10 medical centers) Colombia surveillance project was initiated in early 1997 to monitor the potency and spectrum of six (cefepime, cefotaxime, ceftazidime, cefoperazone/sulbactam, aztreonam, and imipenem) broad-spectrum antimicrobial agents tested against 100 organisms per participant center (802 strains). Ten groups of organisms were tested by a reference-quality method (Etest; AB BIODISK, Solna, Sweden) with results validated by concurrent quality control and additional challenge strain analysis. Results from nine qualifying medical centers were tabulated, and 95.7 to 96.8% of quality assurance tests were within expected ranges. Only cefepime (90.1-100.0% susceptible) and imipenem (96.3-100.0%) were active against all Enterobacteriaceae at > 90% of susceptible isolates using the breakpoint concentrations recommended by the National Committee for Clinical Laboratory Standards. Among ceftazidime- (or cefotaxime- or aztreonam-) resistant Enterobacter spp. and Citrobacter freundii, cefepime remained active, but not cefoperazone with sulbactam. Escherichia coli and Klebsiella spp. strains having resistance phenotypes consistent with extended spectrum beta-lactamase production were discovered in approximately 5 to 10% of isolates. All tested drugs except ceftazidime (31.8-57.7% susceptible) were active against > 94% of oxacillin-susceptible staphylococci. Similar rates of resistance (9.1-14.8%) were observed in Pseudomonas aeruginosa for five of six drugs (not cefotaxime; 15.9% of strains were susceptible). Acinetobacter spp. isolates were most susceptible to imipenem (95.8%), cefepime (86.1%), and cefoperazone/sulbactam (83.3%). Overall for the 1997 order of antimicrobial spectrums for these tested compounds was: imipenem (96.6%) > cefepime (93.6%) > cefoperazone/sulbactam (90.5%) > cefotaxime (74.9%) > aztreonam (74.3% for Gram-negative bacilli only) > ceftazidime (73.2%). These data should be used to guide empiric regimens in Colombia, and additionally will provide a resistance statistical baseline to which future studies in this nation can be compared.

Inmunolocalización subcelular de antígeno tumoral mayor, proteína p53 y antígeno nuclear de proliferación celular en células transformadas por el virus SV40 / Subcellar immunolocalization of SV40-large T antigen, p53 and proliferating cell nuclear antigen in SV40-virus transformed cells

La localización intracelular de proteínas involucradas en el control proliferativo puede ser estudiada mediante técnicas de inmunocitoquímica. Con el propósito de establecer la distribución del antígeno tumoral mayor del virus SV40 (agT), proteína p53 (p53) y antígeno nuclear de proliferación celular (PCNA) tanto en el núcleo como en la superficie de células transformadas por el virus SV40 provenientes de una línea de cultivo, se utilizaron técnicas de inmunoperoxidasa tanto a nivel de microscopia de luz y electrónica como técnicas de inmunofluorescencia. Para lograr la optimización de dichas técnicas en nuestro material se evaluaron distintos procedimientos de fijación, dos métodos de permeabilización celular y se efectuaron modificaciones a las técnicas de inmunoperoxidasa e inmunofluorescencia. Los resultados mostraron inmonorreactividad nuclear conservada para los tres antígenos estudiados cuando se utilizaron fijadores alcohólicos. La fijación con aldehídos permitió una buena morfología y óptima inmunorreactividad a nivel de microscopia de luz, pero las células debieron ser sometidas a un tratamiento previo de permeabilización. A nivel de microscopia electrónica se observó pobre morfología con fijadores alcohólicos, la que mejoró notablemente utilizando fijadores a base de aldehídos. Cuando se utilizó glutaraldehídos como fijador no hubo conservación de la inmunorreactividad. El agT de superficie fue demostrado con una técnica de inmunoperoxidasa modificada para ser aplicada a células sin fijar mantenidas en suspensión.

Long-term outcome of Lyme disease in children given early treatment.

Sixty-three patients treated with appropriate antimicrobial therapy between 1985 and 1990 for physician-documented erythema migrans were identified. A telephone interview program 1 to 6 years after the initial episode of Lyme disease revealed that none of the patients had evidence of carditis, arthritis, or neurologic complications attributable to Lyme disease. A new episode of erythema migrans was reported in 7 (11%) of the patients 1 to 4 years after the initial episode.