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Biomedical subjects

T Bird

Publications and source records attributed to T Bird.

51 records · Page 3Linked to original sources
PubMed1973

Grades of hypothyroidism.

Seventy-nine patients with hypothyroidism and autoimmune thyroid disease were studied, and allotted to one of four categories on the basis of clinical and biochemical features. Firstly, patients with overt hypothyroidism had obvious clinical features of hypothyroidism and abnormal results from routine tests of thyroid function. Secondly, those with mild hypothyroidism, however, had minor and non-specific symptoms, but the routine measurements of circulating thyroid hormone concentration generally lay within the normal range, although they were significantly lower than those seen in subclinical hypothyroidism or in normal subjects. The serum concentration of thyroid-stimulating hormone (TSH) was raised in this group and their symptoms resolve with treatment. Thirdly, patients with subclinical hypothyroidism were asymptomatic, had a raised serum TSH concentration, but all other measurements of thyroid function are indistinguishable from those recorded in people with autoimmune thyroid disease without disturbance of thyroid function and in normal subjects. Lastly, subjects with circulating thyroid antibodies, normal indices of thyroid function, and a normal serum TSH concentration were indistinguishable biochemically from normal subjects.Thus hypothyroidism is a graded phenomenon, the most valuable features for defining the individual grade being the clinical manifestations, the serum TSH concentration, and the presence of circulating antibodies to thyroid tissue.

Autoantibodies↗
PubMed1973

Acute haemolytic anaemia associated with polyagglutinability of red cells.

A 7-week-old albino infant developed acute haemolytic anaemia following an operation for strangulated inguinal hernia. This was considered to be due to polyagglutinability of the red cells, the haemolysis subsiding as the cells returned to normal. The red cell changes were shown to be due to activation of T-antigen, reacting with anti-T in the adult blood transfused to the infant.

Absorption↗
PubMed1973

Evaluation of a tanned red cell technique for thyroid microsomal antibodies.

A haemagglutination test for thyroid microsomal (cytoplasmic) antibodies, using formolized tanned sheep red cells, is described and evaluated. The technique is essentially similar to the thyroglobulin tanned red cell test. It has been shown to be more sensitive and easier to use than the complement-fixation test. A combined screening test to detect both thyroglobulin and microsomal antibodies is described.

Animals↗
PubMed1970

Pathological changes in virus infections of the lower respiratory tract in children.

The pathological changes are described in 22 children with proven or suspected virus infection of the lower respiratory tract. Two main patterns of disease were found: acute bronchiolitis and interstitial pneumonia. Particular viruses were not specifically associated with particular histological changes. The prime importance of the respiratory syncytial virus (RSV) as a cause of disease and death in young infants is again shown. Structural lesions and clinical dysfunction correlate fairly well; in acute bronchiolitis the main lesion is epithelial necrosis when a dense plug is formed in the bronchiolar lumen leading to trapping air and other mechanical interference with ventilation: in interstitial pneumonia there is widespread inflammation and necrosis of lung parenchyma, and severe lesions of the bronchial and bronchiolar mucosa as well. The implications of these structural changes for clinical management are discussed. The possibility of a hypersensitivity reaction in the cot death syndrome is raised, mediated by a serum antibody-antigen-complement reaction.

Adenoviridae↗
PubMedDate not supplied

The effect of supercoiling on the in vitro transcription of the spoIIA operon from Bacillus subtilis.

The spoIIA operon codes for an alternative sigma factor which appears in the early stages of a sigma factor expression cascade during sporulation in Bacillus subtilis. We have used a single round in vitro transcription assay to probe requirements for transcription initiation at the spoIIA promoter. Core RNA polymerase or holoenzyme containing sigma A was reconstituted with sigma H protein and used to transcribe the spoIIA promoter. Formation of heparin resistant transcription initiation complexes required that the spoIIA template be supercoiled. Topoisomers of the spoIIA template were created and transcribed at various temperatures. Changes in the superhelicity of template DNA had a significant influence on the amount of transcription complexes formed at the spoIIA promoter.

Bacillus subtilis↗
PubMedDate not supplied

Control of the initiation of sporulation in Bacillus subtilis by a phosphorelay.

Sporulation in Bacillus subtilis is a developmental process induced as a response to nutritional stress. Activation of sporulation-specific gene transcription is under the control of the spoOA gene product. The SpoOA protein and the SpoOF protein are both homologous to response regulator proteins of two-component regulatory systems which control bacterial responses to a variety of environmental challenges. Response regulators are activated by specific kinases which phosphorylate them. In this study, it was shown that phosphorylation of SpoOA occurs via a phosphotransferase which is the product of the spoOB locus. The phosphodonor in this reaction is the phosphorylated form of SpoOF. It is postulated that SpoOF acts as a secondary messenger that can be phosphorylated by a variety of kinases depending on the particular environmental stress. The series of phosphate transfer reactions in this system is called a phosphorelay. The end product of this series of reactions is SpoOA approximately P which is shown to have greater affinity for the DNA target, the OA box, of SpoOA on the abrB promoter than the unphosphorylated form. SpoOA approximately P, but not SpoOA, was shown to be an activator of transcription of the spoIIA operon which codes for the sporulation-specific sigma factor sigma F. Thus, the initiation of sporulation is dependent on SpoOA approximately P which arises through the phosphorelay and which acts as a transcription factor to repress certain genes, e.g. abrB, and activate others, e.g. spoIIA.

Autoradiography↗