Biomedical subjects

A R James

Publications and source records attributed to A R James.

5 recordsLinked to original sources

PubMed2001

Androgenesis from Festuca pratensis x Lolium multiflorum amphidiploid cultivars in order to select and stabilize rare gene combinations for grass breeding.

Androgenesis using amphidiploid cultivars of Festuca pratensis x Lolium multiflorum as parents, overcame earlier problems that gave rise to widespread plant sterility amongst androgenic Festulolium populations. Two Festuca pratensis x Lolium multiflorum (2n = 4x = 28) cultivars, Sulino and Felopa, were highly amenable to androgenesis and 10% of plants, including some novel androgenic genotypes, had sufficient fertility to produce progeny and further generations. The genomes of amphidiploid cultivars, which represent the F8 generation, were the result of considerable intergeneric chromosome recombination. Moreover, during cultivar development, natural and breeders' selection pressures had led to the assembly of gene combinations that conferred good growth characters and fertility with the removal of putative deleterious gene combinations. Over 80% of the androgenic plants derived from the amphidiploid F. pratensis x L. multiflorum (2n = 4x = 28) had 14 chromosomes and were likely to be dihaploids with a single genome of Lolium and of Festuca. In contrast, hybrids of F. pratensis x L. multiflorum (2n = 2x = 14) found naturally are invariably sterile. Structural reorganization within the genomes of the androgenic Festulolium plants had restored fertility in genotypes expected to contain the haploid genome of Lolium and Festuca. This provided opportunities for their future incorporation in breeding programmes and the development of fertile diploid Lolium-Festuca hybrids. Amongst the androgenic plants, Festulolium genotypes were recovered that conferred excellent drought resistance or freezing tolerance and were thought to be highly suitable for entry into plant breeding programmes.

Adaptation, Physiological↗

PubMed1994

Effect of hyperinsulinaemia on the function of the pituitary-adrenal axis in healthy man.

OBJECTIVE: Circulating insulin levels in themselves have been reported to influence the counter-regulatory hormone response to hypoglycaemia in man. The effect of insulin on a specific aspect of this response was examined during euglycaemia by stimulating the pituitary-adrenal axis with human corticotrophin-releasing hormone (CRH). SUBJECTS: Eight healthy males. DESIGN: Following an overnight fast, insulin was infused at 15 (low) and 60 (high) mU/kg/h from 0900 h for 180 minutes on separate occasions in random order. On each occasion, blood glucose was clamped at euglycaemia, and 1 microgram/kg (i.v. bolus) human CRH was administered at 120 minutes. MEASUREMENTS: Circulating hormone concentrations were determined by radioimmunoassay. Peak cortisol and ACTH responses were compared for the two study conditions. RESULTS: Mean serum insulin levels were threefold higher during the high compared with the low insulin infusion (mean difference 320 pmol/l, 95% confidence interval (CI) 150-490, P < 0.001). Blood glucose levels during the clamps were comparable (mean difference 0.15 mmol/l, 95% CI 0-0.63). Plasma cortisol levels increased following CRH, although the peak concentration was significantly lower during the high insulin infusion (mean difference 36 nmol/l, CI 0-110, P < 0.02). However, peak ACTH levels were comparable for the two insulin levels (mean difference 8 ng/l (1.8 pmol/l), CI 0-50). CONCLUSIONS: The peak cortisol response to CRH was diminished at the higher circulating insulin levels. This was not dependent upon concurrent hypoglycaemia and did not appear to be mediated at the level of the pituitary gland.

Adrenocorticotropic Hormone↗

PubMed1989

[Not Available].

Explore the source record for details and available documents.

Forensic Medicine↗

PubMed1986

[Not Available].

Explore the source record for details and available documents.

France↗

PubMed1985

Herpes simplex virus encephalitis during childhood: importance of brain biopsy diagnosis.

Twelve consecutive pediatric patients 1 day to 11 years of age with suspected herpes simplex virus (HSV) encephalitis underwent brain biopsy. Five were proved to have HSV encephalitis; seven had subdural empyema, malignant glioma, enteroviral encephalitis, (one each), and presumed viral encephalitis, non-HSV (four). Neither epidemiologic, clinical, nor noninvasive laboratory tests were able to help differentiate the two groups of patients. The EEG was more sensitive than the CT scan in demonstrating focal lesions in early HSV encephalitis. In patients with HSV encephalitis, the mean time from hospital admission to appropriate antiviral chemotherapy was 3 days, and the outcome of HSV encephalitis was uniformly poor. In patients with febrile encephalitis-like syndromes with CSF pleocytosis, focal neurologic signs, or other localizing test results (EEG, CT), anticipatory antiviral chemotherapy and brain biopsy are the only hope to prevent the poor outcome associated with HSV encephalitis, to exclude other treatable conditions, and to avoid multiple types of unnecessary empiric therapies.

Biopsy↗