[Clinical course of cytomegalovirus infection in renal transplant recipients].

Background: The incidence of cytomegalovirus infection or reactivation is 8 times more frequent in transplant recipients than in the general population.

Aim: To evaluate the prevalence and usefulness of different diagnostic techniques for cytomegalovirus infection in renal transplant recipients.

Patients And Methods: Twenty nine renal transplant recipients were followed for at least five months.

Polymerase chain reaction for Streptococcus pyogenes used to evaluate an optical immunoassay for the detection of group A streptococci in children with pharyngitis.

Background: In evaluations of sensitive rapid tests for group A streptococci such as the optical immunoassay (OIA), some samples are positive by the antigen test but negative by culture. A method is needed for resolving these discrepant results.

Objective: To develop a PCR-based assay to detect group A streptococci and to use it to establish a reference standard for evaluating an OIA for group A streptococcal antigen.

[Hemophilia A: analysis of intron 18 and intron 7 of factor VIII gene and their role in a diagnostic strategy for carrier detection in a Chilean population].

Hemophilia A is an X-linked disorder of coagulation caused by a deficiency of factor VIII. A larger number of different mutations in the VIII gene have been identified. Thus, the detection of female carriers, depends upon the analysis of DNA polymorphisms in and near the factor VIII gene.

[Activated C protein resistance: laboratory study and prevalence of the defect in the Chilean population].

Activated protein C resistance (APCR) or Factor V Leiden has been recently described as the most prevalent hemostatic abnormality associated with venous thrombosis. In patients with familial thrombophilia, the prevalence of APCR is 19-60% and around 20% in sporadic venous thrombosis. APCR is usually measured by the degree of prolongation of Activated Partial Thromboplastin Time (APTT) on patient's plasma, induced by addition of APC in comparison to normal plasma.

[Incidence of congenital cytomegalovirus infection in newborn infants of different socioeconomic strata].

Cytomegalovirus is the main agent of congenital viral infections. The aim of this study was to compare the incidence of congenital cytomegalovirus infections of two groups of newborns of differing socioeconomic status. Cytomegalovirus was isolated from urine or oropharingeal secretions in 218 children born in a private clinic and 471 born in a public hospital.

[Antigenic types of circulating rotavirus in children with acute diarrhea in Santiago de Chile].

Protective immunity against rotavirus infection is directed against antigenic epitopes on the outer capsid proteins VP7 and VP4. The aim of this study was to characterize the VP7 and VP4 antigenic types circulating in different hospital areas of Santiago, Chile, over different time periods. Between April 1993 and April 1994 a total of 1206 stool samples were obtained from children consulting for acute no bloody diarrhea in 5 hospitals representative of the 5 major health areas of Santiago.

[Molecular study of 6 episodes of nosocomial infections produced by methicillin resistant Staphylococcus aureus].

A critical step in any epidemiologic research concerning nosocomial infections is the precise identification of the responsible pathogen. The present work utilized a molecular approach -plasmids identification, restriction length polymorphism DNA analysis, and random amplified polymorphic DNA- for the characterization of 6 nosocomial outbreaks due to 52 strains of methicillin-resistant Staphylococcus aureus (MRSA). In these episodes, the clinic-epidemiologic and phenotypic analysis (antibiotype) pointed to a nosocomial infection.

Enzymatic DNA amplification (PCR) in the diagnosis of extrapulmonary Mycobacterium tuberculosis infection.

A polymerase chain reaction able to amplify Mycobacterium tuberculosis DNA from clinical samples of extra-pulmonary origin is described. The PCR amplified a 294 base pair DNA fragment spanning positions 5'-782 to 3'-1075 of the 65 kDa M. tuberculosis antigen gene.

[Amplification of 2 different gene segments of Mycobacterium tuberculosis and its usefulness in the diagnosis of tuberculosis].

The infection caused by Mycobacterium tuberculosis is highly prevalent in our country and is considered an emergent pathology in developed countries. The amplification of specific gene segments with diagnostics purposes is an alternative to identify fastidious and slow growing infective agents, being Mycobacterium tuberculosis one of them. Two polymerase chain reactions (PCR) directed to the amplification of a 294bp gene segment encoding a portion of a 65KD heat shock protein and 317 bp gene segment of a repetitive DNA segment (IS 6110) of Mycobacterium tuberculosis, have a sensibility of 80 to 91.

In vitro antibacterial activity of trospectomycin (U-63,366F) against anaerobic bacteria and aerobic gram-positive cocci in Chile.

The in vitro activity of trospectomycin sulfate was compared with those of several antimicrobials, against 301 anaerobic bacteria and 613 aerobic Gram-positive cocci. Trospectomycin was about 4- to 32-fold more active than was spectinomycin. Trospectomycin exhibited consistently good activity against all Bacteroides fragilis group isolates, except Bacteroides vulgatus, and against all other anaerobes comparable or higher to that of clindamycin.

[The impact of molecular biology in medicine].

Over 30 years ago the genetic material of most organisms was shown to be deoxyribonucleic acid. A considerable amount of information on the fine structure and function of cells has accumulated during this time and important methodological and conceptual advances have occurred. The molecular biology techniques, restricted for many years to basic biologic research, are now being introduced in several areas of clinical medicine.

In vitro susceptibility to 10 antibiotics of methicillin-resistant (MRSA) Staphylococcus aureus in Chile.

The in vitro activity of 10 antibiotics was determined for 231 strains of methicillin resistant (MRSA) Staphylococcus aureus. Oxacillin was a very good antibiotic to determine methicillin-resistance. Its agreement with methicillin-resistance was in all the strains tested.

Biosynthesis of the neurofilament heavy subunit in Xenopus oocytes microinjected with rat brain poly(A)+ RNA.

In order to study the expression of the major subunit of neurofilaments (NFs), rat brain poly(A)+ RNA was purified by three different procedures and was injected in Xenopus laevis oocytes. This system was able to translate efficiently the 200 kDa NF subunit as shown by a dot-blot immunoassay and by immunoprecipitation of labeled NF polypeptides.

Assembly in an in vitro splicing reaction of a mouse insulin messenger RNA precursor into a 60-40S ribonucleoprotein complex.

An SP6/mouse insulin RNA precursor containing two exons and one intron can be spliced in a partially purified nuclear extract isolated from MOPC-315 mouse myeloma cells. We have detected the putative RNA splicing intermediate (intron-3'exon) in a lariat form, the excised intron in a lariat form, and the mRNA spliced product. The in vitro splicing reaction of gel-purified RNA precursors requires ATP and Mg2+ and was accompanied by the formation of a 60-40S ribonucleoprotein complex.

Partial purification and properties of a pre-mRNA splicing activity.

Precursor RNA substrates for splicing reaction were synthesized in vitro from a plasmid DNA in which the early region 2 gene of adenovirus 2 was fused to an efficient bacteriophage promoter (Salmonella phage 6). Pre-mRNA splicing activity from nuclear extracts of MOPC-315 mouse myeloma cells was partially purified 108-fold by three chromatographic steps. The in vitro splicing reaction catalyzed by the partially purified fractions was efficient (60-80% substrate conversion) and accurate at the nucleotide level.