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Biomedical subjects

G Lecatsas

Publications and source records attributed to G Lecatsas.

At least 19 recordsLinked to original sources
PubMed1992

Origins of HIV.

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Acquired Immunodeficiency Syndrome↗
PubMed1991

Human T-lymphotropic virus type I-associated myelopathy. A case report.

Tropical spastic paraparesis (TSP) has been reported from various parts of the world for several decades. Recently reports have emerged from Japan and also countries in tropical zones associating endemic TSP with abnormally high titres of antibodies to human T-lymphotropic virus type I (HTLV-I). Data indicate that this lymphotropic retrovirus is neuropathogenic, either by direct invasion or via immunopathological mechanisms. A South African man is described who met the diagnostic criteria of TSP. Both serum and cerebrospinal fluid were antibody-positive for HTLV-I. It is possible that HTLV-I infection may be implicated in the 'myelopathies of undetermined cause' that form a substantial subgroup of spinal cord disease occurring in black South Africans.

Adult↗
PubMed1991

Origin of AIDS.

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Acquired Immunodeficiency Syndrome↗
PubMed1985

Successive urinary papillomavirus excretion, condylomata acuminata and urogenital epithelial malignant disease after renal transplantation.

Of 3 renal allograft recipients who were found to excrete papillomavirus in the urine, 1 has since developed a condyloma, 1 a condyloma and a keratinizing squamous carcinoma and 1 a transitional cell carcinoma. Peroxidase-antiperoxidase staining has confirmed the presence of papillomavirus antigen in the condylomas. The significance of these findings is discussed.

Adult↗
PubMed1985

Bacteriophage D: an IncD group plasmid-specific phage.

The existence of the plasmid incompatibility group D was reaffirmed as a result of compatibility experiments done on plasmids R687, R711b, R778b and R840 which were previously tentatively accepted as constituting the group. The group was further delineated by the isolation of a phage, phage D, which adsorbed specifically to IncD plasmid-encoded pili produced by Escherichia coli K12 strains and strains of Salmonella typhimurium, Proteus morganii and Klebsiella oxytoca harbouring one of these plasmids. Plaque formation, like that of phage pilH alpha, was temperature sensitive in that plaques formed at 26 degrees C but not at 37 degrees C. Plaques were fairly clear, regular in outline and varied from pinpoint to about 1.5 mm in diameter on E. coli hosts where plaques were detected, but on the other hosts the plaques were more turbid and often irregular in outline. The phage did not plate (or propagate) on IncD plasmid-carrying strains of Providencia alcalifaciens, Providencia stuartii or Serratia marcescens. The phage had an isometric hexagonal outline with a diameter of about 27 nm. It contained RNA and resembled two other RNA-containing phages, M and pilH alpha, by being sensitive to chloroform. It adsorbed to the sides of the very distal ends of the shafts of IncD plasmid-coded pili.

Conjugation, Genetic↗
PubMed1985

Characterization of phages derived from strains of Rhodococcus australis and R. equii.

Rhodococcus australis strain CSIR-A201 and R. equii strain CSIR-A655 spontaneously liberated phages A and B, respectively. The phages have different host ranges, but both infect R. rubropertinctus ATCC 14352. phage infection of strains resulted in stable lysogeny. The phages have similar morphologies and belong to the family Styloviridae. The DNA restriction enzyme patterns of the phages differ and do not correspond to those of actinophage phi EC. These temperate phages did not transduce prototrophic or antibiotic resistance markers to appropriate hosts.

Actinomycetales↗
PubMed1979

Properties of R plasmid R772 and the corresponding pilus-specific phage PR772.

R plasmid R772 was isolated from a strain of Proteus mirabilis and is a self-transmissible P-1 incompatibility group plasmid having a molecular weight of about 27 x 10(6). It renders bacterial hosts resistant to kanamycin. Phage PR772 was isolated as a phage dependent on the presence of R772 in bacterial hosts. It is hexagonal-shaped with a diameter of 53 nm, has a thick inner membrane and no tail. Vaguely defined appendages are sometimes apparent at some vertices and the phage possesses double-stranded DNA. The DNA has a guanine plus cytosine molar content of 48%. The phage is sensitive to chloroform and has a buoyant density of 1.26 g cm(-3). These observations suggested that the inner membrane of the phage could contain lipid. Phage PR772 differs in morphology from the double-stranded DNA plasmid-specific phages PR4 and PRR1 which adsorb to tips and sides, respectively, of sex pili coded for by P-1 incompatibility group plasmids. Phage PR772 formed clear plaques which varied in diameter. Serologically, phages PR772 and PR4 are possibly related though very distantly, but the two phages have identical host ranges. Phage PR772 adsorbed by one of its apices to tips of sex pili coded for by plasmid R772 in Escherichia coli. It also formed plaques on Salmonella typhimurium Proteus morganii and Providence strains harbouring this plasmid as well as strains of E. coli carrying plasmids of incompatibility groups N or W. The phage produced areas of partial clearing on lawns of P. mirabilis PM5006 harbouring plasmid R772, the P-1 incompatibility group plasmid RP4, the W group plasmid RSa or the N group plasmid N3, and on lawns of Providence strain P29 carrying plasmid RP4.

Bacteriophages↗