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Biomedical subjects

T J Harris

Publications and source records attributed to T J Harris.

85 records · Page 5Linked to original sources

An assessment by competition hybridization of the sequence homology between the RNAs of the seven serotypes of FMDV.

A comparison has been made of the RNAs of the seven serotypes of foot-and-mouth disease virus (FMDV) by competition hybridization. Homology among the three European serotypes A, O, C and the Asia I serotype was 60 to 70%. Similar homologies were found among the three Southern African Territories serotypes (SAT I, SAT 2, SAT 3), but homology between the two groups was much lower (25 to 40%). Homology between the RNAs of subtypes within serotypes A and O was greater than 70%. Double competition experiments with the Eropean serotypes indicate sharing of nucleotide sequences.

Aphthovirus↗

Comparison of swine vesicular disease virus and Coxsackie B5 virus by serological and RNA hybridization methods.

The relatedness of swine vesicular disease virus (SVDV) and Coxsackie B5 virus has been studied by virus neutralization and immunodiffusion tests and by hybridization of the virus RNAs. Clearly defined differences between the two viruses were found by the three methods. Isolates of SVDV from several countries were very closely related but could be differentiated. Recent isolates of Coxsackie B5 virus also appeared to be similar but clear differences could be detected between these and the prototype (Faulkner) strain of the virus. The SVDV isolates were more closely related to the Faulkner strain than to the recent isolates of Coxsackie B5 virus. Perhaps of more importance, the Faulkner strain was more closely related to SVDV than it was to the recent Coxsackie B5 isolates. The significance of these observations in relation to the recent emergence of swine vesicular disease is discussed.

Animals↗

The location of the ploy(C) tract in the RNA of foot-and-mouth disease virus.

Fragments of foot-and-mouth disease virus RNA of decreasing size, containing the 3' poly(A) sequence have been prepared by alkali treatment and sucrose gradient centrifugation followed by oligo(dT)-cellulose affinity chromatography. Polyacrylamide gel electrophoresis of the ribonuclease T1 resistant oligonucleotides from these polyadenylated fragments has enabled us to locate the position of some of the longer oligonucleotides on the RNA. In particular the poly C tract has been shown to be near the 5' end of the RNA; The possible function of the poly(C) tract is discussed in the light of these findings.

Aphthovirus↗

The synthesis of polyadenylated messenger RNA in herpes simplex type I virus infected BHK cells.

The pattern of polyadenylated messenger RNA (mRNA) synthesis in BHK cell monolayers, infected under defined conditions with herpes simplex type I virus has been investigated by polyacrylamide gel electrophoresis or pulse-labelled RNA isolated by oligo dT-cellulose chromatography. Two classes of mRNA molecules were synthesized in infected cells; these were not detected in uninfected cells. The rate of synthesis of the larger, 18 to 30S RNA class reached a maximum soon after injection and then declined, whereas the rate of synthesis of the 7 to 11 S RNA class did not reach a maximum until much later and did not decline. In the presence of cytosine arabinoside, the rate of mRNA synthesis in infected cells was reduced but the electrophoretic pattern remained the same.

Cell Line↗

Melanoma of the head and neck in Queensland.

The incidence of melanoma in Queensland, 40 cases per 100,000 population, is the highest in the world. In this series of 740 melanomas over a 7-year period at the Royal Brisbane Hospital, 21.75% occurred on the head and neck. Of these, 46.5% arose in Hutchinson's melanotic freckle and 54.8% were histologically superficial, that is, Clark Levels I and II or less than 0.76 mm in thickness, or both. As local recurrence and distant metastasis is infrequent in superficial melanoma, less radical surgical excision of these lesions is advocated than for thicker lesions or those exhibiting a greater depth of invasion, where aggressive excision and even regional node dissection may be required. Anatomical variations in areas such as the nose, eyelid, ear, and scalp influence patterns of spread and necessitate differences in treatment at each site.

Adolescent↗

Sequence of human tissue inhibitor of metalloproteinases and its identity to erythroid-potentiating activity.

Collagen fibres form the stable architecture of connective tissues and their breakdown is a key irreversible step in many pathological conditions. The destruction of collagen is usually initiated by proteinases, the best known of which is the metalloproteinase collagenase (EC 3.4.24). Collagenase and related metalloproteinases are regulated at the level of their synthesis and secretion, through the action of specific stimuli such as hormones and cytokines, and also at the level of their extracellular activity through the action of a specific inhibitor, TIMP (tissue inhibitor of metalloproteinases), which irreversibly forms inactive complexes with metalloproteinases. Although the mechanisms governing the production of TIMP are unknown, immunologically identical forms of this glycoprotein have been detected in a wide variety of human body fluids and cell and tissue culture media. We therefore suggested that under physiological conditions this ubiquitous inhibitor predominates over active metalloproteinases and that tissue destruction may arise when any perturbation of this controlling excess arises. However, further progress towards testing this theory has been hindered by a lack of knowledge about the structure of TIMP and insufficient material for studying it in model systems. Here we describe the structure of TIMP predicted from its complementary DNA, its synthesis in Escherichia coli and transfected animal cells, and the finding that it is identical to a protein recently reported to have erythroid-potentiating activity (EPA).

Amino Acid Sequence↗