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Biomedical subjects

D Carson

Publications and source records attributed to D Carson.

At least 19 recordsLinked to original sources
PubMed1992

Change in the oestrogen receptor status of breast cancer with age--comparison of two types of assay.

The oestrogen receptor (ER) is considered to be an essential component of the mechanism of response of a breast tumour to endocrine therapy, but ER measurements have proved to have only modest predictive value. In the present study, we have examined ER status by both immunocytochemical assay (ER-ICA) on a fine needle aspirate and by radioligand-binding assay (DCC) on an excised portion of tumour. There was a correlation between the ER level detected by the two assays (Spearman's r = 0.77 for DCC versus ER-ICA staining intensity, r = 0.70 for DCC versus ER-ICA percentage of cells stained, P < 0.0001, n = 137 in each case). Each assay showed an increasing proportion of ER+ve results with increasing patient age. In the case of ER+ve tissues only, while ER concentration by DCC assay increased steadily with age (r = 0.39, P < 0.0001, n = 108), the ER-ICA assay revealed that, staining intensity increased with age (r = 0.26, P = 0.001, n = 149) but the percentage of cells stained did not (r = 0.08, P = NS, n = 149). It is concluded that increasing endocrine responsiveness with advancing age could reflect the increasing proportion of ER+ve tumours with increased levels of ER per cell (as indicated by staining intensity) rather than increasing proportion of ER+ve cells.

Adult↗
PubMed1992

Multiple lentigines, myxoid tumours and endocrine overactivity; four cases of Carney's complex.

Four patients with Carney's complex, one sporadic and three familial, are described. The sporadic case was a young male with centrofacial lentigines, who developed cyclical Cushing's syndrome secondary to bilateral pigmented nodular adrenocortical disease, two separate left atrial myxomas, and buccal mucosal myxomas. The three familial cases, who all had varying degrees of centrofacial/mucosal lentigines and cutaneous myxoid tumours, were a woman with myxoid mammary fibroadenomatosis and a left atrial myxoma, her daughter who developed a prolactin-secreting pituitary adenoma, and her son who had bilateral large-cell calcified Sertoli cell testicular tumours, and an axillary psammomatous melanotic schwannoma.

Adenoma↗
PubMed1990

Occurrence of two germline-related rheumatoid factor idiotypes in rheumatoid arthritis and in non-rheumatoid seropositive individuals.

Human rheumatoid factor (RF) paraproteins express two distinct light chain cross-reactive idiotypes defined by the monoclonal antibodies 17.109 and 6B6.6. These germline gene-related cross-reactive idiotypes are both carried on VK3 light chains and are each present on about one-third of IgM RF paraproteins. We assessed the degree to which these idiotypes are represented in polyclonal RFs. We used rheumatoid arthritis (RA) and non-RA RF-positive sera selected from a large cross-sectional population study (the Mini-Finland Health Survey), and sera from a community-based follow-up study of recent-onset RA patients from Heinola, Finland. In the Mini-Finland Health Survey, elevated levels of the 17.109 RF idiotype were seen in sera of 13% of the RA and 19% of the non-RA group; 6B6.6 RF was seen in 26% of the RA and 28% of the non-RA group. In sera of the Heinola follow-up study, 17.109 RF was seen in 12% initially, but in only 3% at 8 years. Similarly, 6B6.6 RF was detected in 25% initially, but in only 7% at 8 years. Ten sera positive for RF prior to the onset of clinical RA were identified from individuals of a second large population study from Finland (North Karelia project); two of these sera exhibited the 6B6.6 idiotype; none exhibited the 17.109 idiotype. The data are consistent with the concept that these germline gene-related cross-reactive RF idiotypes occur frequently in the polyclonal RF of non-RA as well as RA sera, and that in RA the idiotypes may sometimes be reduced or lost as a consequence of somatic diversification of the RF through somatic mutation, usage of new germline genes, or both.

Arthritis, Rheumatoid↗
PubMed1990

Evidence that secondary rat Schwann cells in culture maintain their differentiated phenotype.

Schwann cells, on receiving the correct signal, will encircle an axon and wrap it with a myelin sheath. To begin examining some of the mechanisms underlying the process of myelination in vitro, we isolated Schwann cells from the sciatic nerves of neonatal rats and generated large cell populations with cholera toxin. The immunological and biochemical properties of these secondary Schwann cells were characterized after five to seven passages in the absence of axonal contact. These cells continued to express antigens found in both myelinating (P0 and 2',3'-cyclic nucleotide phosphohydrolase) and nonmyelinating cells in vivo (A5E3 and glial fibrillary acidic protein) in addition to the markers common to both types of cells (Ran-1, 217c, S-100, and laminin). Biochemical analyses showed that these cells synthesize the very-long-chain fatty acids (22-26 carbon atoms) found in myelin membranes. Moreover, the enzymes required for the synthesis of myelin glycolipids (including sphingosine acyltransferase, UDP-galactose:ceramide galactosyltransferase, and cerebroside sulfotransferase) were still active, and metabolic labeling studies showed that galactocerebroside and sulfatide were synthesized even though the galactocerebroside pool was insufficient to be detected by immunostaining. Secondary Schwann cells also synthesized four species of myelin basic protein and the major structural glycoprotein in myelin, P0. The pathway necessary for glycosylation of P0 protein remained active, and an analysis of the oligosaccharide chain revealed that approximately 70% was processed to a complex form. In summary, we found that secondary Schwann cells still express most of the immunological markers of differentiated cells and continue to synthesize low levels of myelin components. Therefore, Schwann cells do not dedifferentiate in culture, as previously believed.

Animals↗
PubMed1990

Cerebral oedema complicating diabetic ketoacidosis.

Signs of raised intracranial pressure (ICP) developed during treatment of diabetic ketoacidosis in a young child. A CT scan revealed cerebral oedema and direct measurement confirmed elevated ICP. Aggressive treatment was successful in maintaining cerebral perfusion pressure. The child survived with mild handicap in contrast to the poor outcome of previous reports.

Brain Edema↗
PubMed1989

Structural and idiotypic characterization of the L chains of human IgM autoantibodies with different specificities.

We have determined the V region amino acid sequence and/or serologic markers (kIIIb, PSL2, and PSL3) of 24 IgM monoclonal autoantibodies with specificities of anti-gamma-globulin (RF), anti-I (cold agglutinin), anti-low density lipoprotein and anti-intermediate filaments. The data emphasize the overwhelming selection of the HumKv325/VkIIIb L chain for this family of autoantibodies. The few amino acid substitutions found within the VL regions were mainly concentrated in the complementarity-determining region 1. JK and CK genes did not show the same pattern of restriction. There is a good correlation between the amino acid sequence and the presence of the kIIIb marker. The idiotypic marker PSL2 was present in 34 out of 35 kIIIb L chains analyzed (97%) and the PSL3 in 27 (80%). Moreover, the hydrophilicity and antigenic profiles of these L chains corroborate the presence of the epitopes detected by the anti-CRI. These results demonstrate a restricted selection of the Vk genes used by a family of self reacting proteins, and an unusual evolutionary conservation of the idiotypic structure that may be involved in the network regulation.

Agglutinins↗
PubMed1989

Pituitary function studies in a case of mild Hunter's syndrome (MPS IIB).

Pituitary function studies were performed in a patient with mild Hunter's syndrome (mucopolysaccharidosis type IIB, MPS IIB) in order to exclude growth hormone deficiency as a possible contributing cause of his short stature. The results indicated that anterior pituitary function and, in particular, growth hormone secretion was normal. The most likely explanation for the short stature is an osseous growth plate disturbance with infiltration of the epiphyses by mucopolysaccharides.

Adolescent↗
PubMed1987

Alternative measures of diarrhoeal morbidity and their association with social and environmental factors in urban children in The Gambia.

Diarrhoeal morbidity was studied during a 15-week period of the rainy season in 244 children aged 6 to 35 months in an urban Gambian community. The average prevalence of diarrhoea was 12.0% and the mean number of episodes per child varied between 2.4 and 2.9 depending on the definition of an episode. The number of chronic episodes lasting 14 d or more was tripled when 7 rather than one diarrhoea-free days were required to define a new episode. Neither prevalence nor the number of episodes varied significantly with age or sex. There was little association between the social and environmental characteristics of the children and diarrhoeal morbidity. The implications of using differing measures of diarrhoeal morbidity are discussed.

Child, Preschool↗
PubMed1986

Comparative studies to determine the efficiency of 6 methylpurine deoxyriboside to detect cell culture mycoplasmas.

Studies were performed to compare three methods to detect mycoplasmal infection of cell cultures. The methods included microbiological assay by inoculation into broth and onto agar with anaerobic incubation, fluorescent DNA staining by Hoechst 33258, and mycoplasmal mediated cytotoxicity by 6 methylpurine deoxyriboside (6MPDR). Fluorescent DNA staining and 6MPDR assays were performed in an indicator cell culture system. A total of 2589 cell cultures were assayed. Mycoplasmas were detected in 174, an incidence of 6.7%. Species isolated were: Acholeplasma laidlawii, Mycoplasma orale, M. arginini, M. hyorhinis, M. fermentans, M. pirum, and M. pneumoniae. In separate studies, 6MPDR also detected infection with Spiroplasma mirum when this organism was deliberately inoculated into cell cultures. The efficiencies of microbiological testing, fluorescent DNA assays, and 6MPDR were 43.1, 98.8, and 97.1%, respectively.

Bisbenzimidazole↗
PubMed1986

Amino acid sequence of a light chain variable region of a human rheumatoid factor of the Wa idiotypic group, in part predicted by its reactivity with antipeptide antibodies.

Antipeptide antisera were raised to the second and third complementarity-determining regions of the light chain derived from a human monoclonal IgM (Sie) which had antigammaglobulin activity and belonged to the Wa cross-reactive idiotypic group of human rheumatoid factors, two of whose members (Sie, Wo1) had been previously sequenced in our laboratory (Andrews and Capra, Biochemistry 20, 5816-5822, 1981). These antisera were found to react with the light chain of another human monoclonal IgM (Go1) that shared the Wa idiotype while antipeptide antisera made to the third CDR of the Sie heavy chain failed to react. The amino acid sequence of the variable region of the Go1 light chain was found to be highly homologous to the light chain of Sie from which the synthetic peptides were derived, particularly in the framework regions and the second and third CDR. This study illustrates that antipeptide antisera are valuable and specific probes for determining the relationship between molecules which exhibit similar antigen binding or idiotypic specificities and, furthermore, such antisera are able to predict amino acid sequences with surprising precision.

Amino Acid Sequence↗
PubMed1985

Doctors in the witness box.

The aim of this paper is not to show how medical witnesses can play tricks on lawyers but to try to help show how doctors and others can remain in control of their evidence. If the courts are to obtain the best information to make the best decisions then they will not be helped by witnesses unable to say what they mean.

Communication↗