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Biomedical subjects

L Aron

Publications and source records attributed to L Aron.

7 recordsLinked to original sources
PubMed1992

Exercise dependent complete left bundle branch block.

Eleven patients with an exercise dependent complete left bundle branch block (CLBBB) were followed-up over a period of 2-13 years (mean 6.5 +/- 3.8). Their ages ranged from 19 to 62 years (mean 48). Four patients complained of chest pain on effort and one of palpitations. All patients underwent a clinical examination, 12 lead ECG, routine blood tests, chest X-ray, a multistage exercise test, echo Doppler, radionuclide ventriculography with TC99 and 48-h Holter monitoring. Ten were submitted to a coronary angiography with left ventriculography. The ECG at rest displayed a normal ECG in seven patients and an incomplete left bundle branch block (ILBBB) in four patients. The onset heart rate (HR) of CLBBB ranged from 95-146 beats.min-1 (mean 123) and the offset HR75-135 (mean 102 beats.min-1). Coronary angiography showed three-vessel disease in two patients and an obstruction of the left anterior descending coronary artery (LAD) in the third. In the other seven patients all the investigations (including coronary angiography) were normal. During the follow-up period the HR at onset of CLBBB decreased from 145 beats.min-1 to 100 beats.min-1 in four patients but no coronary artery disease (CAD) could be proven at coronary angiography. In our series chest pain did not always signify the presence of CAD. We conclude, that in patients with exercise-dependent CLBBB the prognosis is good if no underlying heart disease can be detected. It appears from our limited experience that an exercise-dependent CLBBB at heart rate below 125 beats.min-1 does not by itself constitute a sign of CAD.

Bundle-Branch Block↗
PubMed1992

Production and characterization of monoclonal antibodies to psittacine beak and feather disease virus.

Monoclonal antibodies specific for the virus that causes psittacine beak and feather disease (PBFD) were produced by fusing spleen cells from mice immunized with purified concentrated PBFD virus with mouse myeloma cell line Sp2/0. The resulting hybridomas were tested for reactivity against whole purified virus by an enzyme-linked immunosorbent assay (ELISA) system. Four clones, designated 15H8, 8E3, 11G12, and 2C3, were subcloned by limiting dilution. Isotyping indicated that clone 15H8 was secreting IgG, whereas the remaining clones secreted IgM. The secreted immunoglobulins were characterized by reactivity against purified PBFD virus using immunoblotting procedures, by immunohistochemical staining of virus-induced lesions in infected tissues, and by inhibition of PBFD virus agglutination of cockatoo erythrocytes. Antibodies secreted by clones 15H8 and 8E3 had the strongest activity against purified whole virus. Only immunoglobulin secreted by the clone 15H8 could be used to detect viral antigen in infected tissues. None of the monoclonal antibodies had hemagglutination-inhibition activity.

Animals↗
PubMed1990

Chromosomal DNA, iron-transport systems, outer membrane proteins, and enterotoxin (heat labile) production in Salmonella typhi strains.

We examined a representative collection of Salmonella typhi strains from Chile, Peru, Mexico, India, and England for the presence of several properties. All strains had a conserved pattern of outer membrane proteins, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The electrophoresis profiles of chromosomal DNA digested with EcoRI and PstI restriction enzymes were similar for all the strains. A conserved pattern of hybridization was observed when digested chromosomal DNA was hybridized with DNA probes for the 36-kilodalton porin, enterobactin synthesis, and enterobactin receptor genes. All the strains produced enterobactin but not aerobactin in bioassays. None of the strains produced heat-labile toxin, as measured by an enzyme-linked immunosorbent assay. Colony and Southern hybridizations with DNA probes for aerobactin synthesis and its receptor and heat-labile toxin genes were negative. These results indicate that S. typhi strains from different origins have similar phenotypic and genetic properties and, as has been suggested, constitute a clone.

Bacterial Outer Membrane Proteins↗
PubMed1990

Free association and changing models of mind.

The method of free association, like most major psychoanalytic concepts, was developed in and has been conceptually tied to a one-person, intrapsychic, drive psychology. Psychoanalysts who have retained the classical, drive-structure metapsychology have continued to emphasize the free association method, while those who have shifted to a relational, two-person, interactional or interpersonal point of view have often minimized or abandoned the free association method. This article explores this unfortunate dichotomy and examines the ways in which the free association method, stripped of its unnecessary tie to drive theory and reconceptualized within the context of a two-person psychology, remains a valuable clinical method. Free association, as a method, can be useful to psychoanalysts of all theoretical orientations as a reminder of Freud's most important discoveries, that is, of unconscious mental life, psychic determinism, psychic continuity, and meaning, as well as of the value and priority of careful, restrained, and disciplined listening to patients and of taking our lead from them. The method of free association, with the corresponding assumption of the analyst's evenly hovering attention, provides a fundamental context within which our personalities and theoretical biases, instead of being disruptions or impositions, become active and analyzable aspects of the analytic process.

Countertransference↗
PubMed1987

Cloning, expression and characterization of the 36 KDal Salmonella typhi porin gene in Escherichia coli.

A recombinant plasmid containing the gene for the 36 KDal porin of Salmonella typhi has been identified in a cosmid library of S. typhi propagated in Escherichia coli. The recombinant clone was identified by its ability to endow E. coli with susceptibility to porin specific phages, and by the appearance in the outer membrane of E. coli containing the clone of a new protein of 36 KDal. While the porin confers upon a porinless mutant of E. coli an increased susceptibility to beta-lactam antibiotics, it does not react with serum from patients with typhoid fever in immunoblotting assays.

Bacterial Outer Membrane Proteins↗