Biomedical subjects

S J Barrett

Publications and source records attributed to S J Barrett.

5 recordsLinked to original sources

PubMed2000

Cloning, sequencing and analysis of the pucC genes from Rubrivivax gelatinosus strain 151 and Rhodopseudomonas acidophila strain 10050.

The pucC genes of Rubrivivax gelatinosus strain 151 and Rhodopseudomonas acidophila strain 10050 have been identified, cloned and sequenced. In Rubrivivax gelatinosus the arrangement of the pucC gene with regard to the pucBA genes was shown to differ from that found in other species of photosynthetic bacteria. The Rhodopseudomonas acidophila pucC was found downstream of four new pucBA gene pairs, bringing the sequenced pucBA pairs to a total of eight in this strain. The predicted PucC protein sequences were compared to those of PucC from other species and showed high similarity. Similarity was also seen to more distantly related proteins LhaA and orf428 of Rhodobacter capsulatus, orf G115 of Rhodospirillum rubrum and 'orf428' from Synechocystis sp. PCC6803. An analysis of the predicted secondary structure of these proteins is given, and their structural similarity to proteins in the Major Facilitator Superfamily is discussed with regard to their possible function.

Journal Article↗

PubMed1999

Plantar fasciitis and other causes of heel pain.

The most common cause of heel pain is plantar fasciitis. It is usually caused by a biomechanical imbalance resulting in tension along the plantar fascia. The diagnosis is typically based on the history and the finding of localized tenderness. Treatment consists of medial arch support, anti-inflammatory medications, ice massage and stretching. Corticosteroid injections and casting may also be tried. Surgical fasciotomy should be reserved for use in patients in whom conservative measures have failed despite correction of biomechanical abnormalities. Heel pain may also have a neurologic, traumatic or systemic origin.

Diagnosis, Differential↗

PubMed1997

Regulated expression vectors demonstrate cell-type-specific sensitivity to human immunodeficiency virus type 1 Nef-induced cytostasis.

The nef gene product of both human and simian immunodeficiency viruses is critically important for virus replication and disease progression in vivo. However, the precise biological function of Nef remains poorly characterized in vitro, with previous reports suggesting that Nef might be either cytotoxic or cytostatic. As a result of difficulties encountered by several groups in establishing cell lines constitutively expressing Nef, we have developed two inducible systems resulting in stable Nef expression in various mammalian cell lines. Tetracycline-regulated Nef expression was achieved in HeLa cells but could not be established in human T cell lines. Jurkat E6-1 T cell and RAW264.7 murine macrophage cell lines expressing a regulated nef gene were generated using a system in which Nef expression was controlled by a mutated version of the heavy metal-inducible human metallothionein IIA promoter. Induction of high levels of Nef expression in HeLa-Nef and Jurkat-Nef cells resulted in a moderate (2-fold) and a dramatic (10-fold) retardation of cell growth respectively, supporting the contention that Nef may be a cytotoxic or cytostatic factor. This property was also observed at low basal levels of Nef expression in RAW264.7-Nef macrophage clones (5-fold reduction in growth) and was associated with an altered morphological phenotype suggesting that different cell types may be more susceptible to the cytostatic activity of Nef. The regulated Nef-expression systems provide tools for investigating the molecular basis of Nef function, including Nef-mediated cytopathogenicity, CD4 down-regulation and enhancement of virus infectivity.

Animals↗

PubMed1996

A new species of Neisseria from the dental plaque of the domestic cow, Neisseria dentiae sp. nov.

A new species of the genus Neisseria is proposed, Neisseria dentiae sp. nov. The organism is found in dental plaque of domestic cows. It resembles N. animalis, N. canis and N. iguanae phenotypically but is distinguished from the first two by being positive for acidification of gluconate, D-glucose and usually D-fructose, and from the third by lack of predominant tetrad arrangement, lack of distinct alpha-haemolysis and by growing on nutrient agar and usually acidifying D-fructose. It is suggested that it may have significance for dental microbiology because members of the genus rapidly utilize oxygen and this may contribute to the anaerobic microenvironment found in dental plaque.

Animals↗

PubMed1994

A numerical phenotypic taxonomic study of the genus Neisseria.

A numerical phenotypic taxonomic study of 315 strains of Neisseria and some allied bacteria examined for 155 phenotypic tests showed 31 groups, most of which were reasonably distinct. These fell into four major areas. Areas A, B and C contained species of Neisseria, whereas area D contained the organisms known as 'false neisserias' together with Branhamella, Moraxella and Kingella species. Area A contained N. gonorrhoeae (which showed two subgroups), N. meningitidis (with two subgroups, and N. cinerea closely associated), N. polysaccharea, N. elongata subsp, glycolytica and N. lactamica. Area B contained mainly organisms from the human nasopharynx, and the nine groups were not very distinct: only three, N. mucosa, N. perflava and N. sicca could be recognized by the presence of type strains, and there was little relationship between taxonomic position and species epithets. Area C contained several groups from animals, N. animalis, N. canis and two phenons that may be justified as new species of Neisseria, one from lizards and the other from dental plaque of herbivores. Area C also contained N. elongata, N. subflava (with N. flavescens), type strain of Morococcus cerebrosis and the CDC groups M-5 (N. weaveri) and EF-4. Area D contained Branhamella catarrhalis, a combined group which consists of strains of the 'false neisserias' N. caviae and N. cuniculi, the 'false neisseria' N. ovis, and a group of Moraxella strains. A small group representing Kingella kingae is included in area D. Mean test error was 1.7%.

Models, Biological↗