Biomedical subjects

E Barratt

Publications and source records attributed to E Barratt.

10 recordsLinked to original sources

PubMed1992

An integrated approach to studying regulation of production of the antibiotic methylenomycin by Streptomyces coelicolor A3(2).

A physiological and molecular biological study was made of the control of methylenomycin biosynthesis by Streptomyces coelicolor A3(2). A simple and reliable assay for this antibiotic was developed. Conditions that permit the synthesis of methylenomycin by S. coelicolor cultures grown in defined medium were elucidated: a readily assimilated carbon and nitrogen source is required. Under these conditions methylenomycin is produced late in the growth phase, at the time of transition from exponential to linear growth. Provided that the phosphate concentration in the medium is kept high, there is synthesis of methylenomycin but not of the other secondary metabolites that this strain can produce. These conditions were used to study the transcription of the methylenomycin gene cluster during the transition from primary to secondary metabolism. The biosynthetic genes of at least one of the mmy transcription units appear to be transcribed before the mmr resistance determinant. The possibility that methylenomycin induces the transcription of mmr is discussed.

Acetates↗

PubMed1991

The diagnosis of intermittent explosive disorder in violent men.

In a study of violent men, 443 symptomatic adult male volunteers were evaluated for presence of intermittent explosive disorder (IED). Investigators first established presence of severe and frequent violent outbursts not readily explainable by another disorder. Seventy-nine violent men were so selected. Of these, 26 had excessive impulsivity, an exclusionary criterion for IED. Twenty-one were excluded because of other, exclusionary mental disorders. Violent behavior of five subjects was deemed proportionate to the provocation. Insufficient data were obtained for an accurate diagnoses of IED in 12 subjects. Fifteen subjects satisfied all criteria for IED, i.e., 18.9 percent of sufficiently violent men without other major psychopathology or 1.49 percent of all 443 men who complained of violence. Epidemiologic and validity aspects of IED are discussed.

Adult↗

PubMed1989

Ultrastructural and histochemical changes in the murine zona pellucida during the final stages of oocyte maturation prior to ovulation.

The ultrastructural morphology of the mouse zona pellucida was studied in preovulatory follicles from the ovaries of immature mice treated with exogenous gonadotrophins. The ovaries were fixed in the presence of cetylpyridinium chloride, which precipitates carbohydrates, so that their loss during fixation and processing is substantially reduced. The semi-thin araldite sections obtained from osmicated material were viewed by conventional light microscopy, while the ultra-thin sections were examined by transmission electron microscopy. A parallel series of semi-thin sections of non-osmicated ovaries was deresined and subsequently stained with periodic acid Schiff (PAS). The morphological appearance of the zona pellucida in preovulatory oocytes changed during the final stages of oocyte maturation. A close correlation was observed between the ultrastructural appearance of the zona pellucida and that observed following PAS staining during the period studied. Real differences were observed in the location, density, and distribution of glycoconjugates within the zona pellucida during the final stages of oocyte maturation prior to and immediately following germinal vesicle breakdown. Similar changes in the zona were observed in adult females autopsied during proestrus and oestrus. The changes in the density and distribution of glycoconjugates are likely to have important consequences for fertilization by affecting sperm-zona binding and sperm-egg interactions.

Animals↗

PubMed1989

The uptake of [3H] glucosamine-labelled glycoconjugates into the perivitelline space of preimplantation mouse embryos.

Autoradiography has been used to follow the synthesis and migration of labelled glycoconjugates into fertilized and unfertilized mouse eggs. Adult female mice were paired individually with males and injected with 100 microCi [3H] glucosamine, either when they were paired with males or at the time a vaginal plug was first detected. The mice were killed at intervals after the injection of label and 5-microns and semi-thin sections of the oviducts were processed for autoradiography. Labelled glycoconjugates passed rapidly into the perivitelline space of fertilized and unfertilized mouse eggs. There was a positive correlation between the density of label within the zona pellucida and the perivitelline space. Labelled glycoconjugates were maintained within the perivitelline space of many developing embryos for at least 48 h despite very low levels of label within the oviduct by this time. Other 2-cell embryos were only lightly labelled. It is suggested that labelled glycoconjugates may be derived from secretions of the cumulus cells which surround the egg at ovulation rather than from oviductal secretions.

Animals↗

PubMed1989

Community psychiatric nurses: their self-perceived roles.

The self-perceived role of 16 community psychiatric nurses (CPNs) were analysed with reference to four conceptual models of psychiatric illness. The roles discussed by the CPNs echoed many of those found in previous research. Overall the CPNs used different models of illness when discussing various aspects of their roles. It is believed that the models of illness preferred by CPNs may be a useful reflection of the role they may have in caring for different client groups.

Attitude of Health Personnel↗

PubMed1979