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Biomedical subjects

J Atkin

Publications and source records attributed to J Atkin.

At least 19 recordsLinked to original sources
PubMed2001

Imprinting status of 11p15 genes in Beckwith-Wiedemann syndrome patients with CDKN1C mutations.

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder characterized by somatic overgrowth, congenital malformations, and predisposition to childhood tumors. Aberrant expression of multiple imprinted genes, including H19, IGF2, KCNQ1OT1, and CDKN1C, has been observed in BWS patients. It has been estimated that mutations in CDKN1C occur in 12-17% of BWS patients. We have screened 10 autosomal dominant pedigrees and 65 sporadic BWS cases by PCR/heteroduplex analysis and DNA sequencing and have identified four mutations, two of which were associated with biallelic IGF2 expression and normal H19 and KCNQ1OT1 imprinting. One patient demonstrated phenotypic expression of paternally transmitted mutation in this maternally expressed gene, a second proband is the child of one of a pair of monozygotic twin females who carry the mutation de novo, and a third patient exhibited unusual skeletal changes more commonly found in other overgrowth syndromes. When considered with other studies published to date, this work reveals the frequency of CDKN1C mutations in BWS to be only 4.9%. This is the first report of an analysis of the imprinting status of genes in the 11p15 region where CDKN1C mutations were associated with loss of IGF2 imprinting and maintenance of H19 and KCNQ1OT1 imprinting.

Amino Acid Sequence↗
PubMed2001

District nurses and home carers 3: project evaluation.

This article, the last in a series of three, discusses the evaluation of a project established to provide a programme of education for social services' home carers that focused on the development of skills relating to care work. This education was delivered by district nurses (DNs) to address a number of problems associated with the provision of personal care identified by the home carers and their DN colleagues. An action research framework was used to improve collaborative working between the staff of the two disciplines. The article outlines some of the key findings from the evaluation of the project in relation to the structure, the process and the outcome of the project. The project evaluation was mainly positive and this success can be partly attributed to the fact that an action research method was used to drive the project.

Clinical Competence↗
PubMed1996

Alterations in glomerular permeability in streptozotocin-induced diabetic rats.

The alteration in glomerular basement membrane permeability associated with microangiopathy in streptozotocin-induced diabetic rats was studied by determining the movement across the glomerular basement membrane of anionic ferritin probes injected into rats at different points in the development of the disease. Visualization of the concentration gradient of anionic ferritin and changes in ultrastructure was accomplished by electron microscopic examination of renal tissue prepared from both control and diabetic rats. In all control rats, the anionic ferritin did not leave the glomerular capillary lumen, nor were there any changes in the normal morphology of the glomerular capillary wall. In the diabetic animals, the concentration of anionic ferritin shifted from the capillary lumen in the abluminal direction. Distinct morphologic changes, such as widening of endothelial intercellular junctions, focal detachment of podocyte foot processes, and extensive thickening of the glomerular basement membrane, were noted in the diabetic rat, and these changes appear to correlate with the observed increase in permselectivity of anionic ferritin across the glomerular capillary wall.

Animals↗
PubMed1991

Electron microscopy of changes in lower extremity muscles in Duchenne muscular dystrophy.

Duchenne muscular dystrophy is a genetic disease with a sex-linked pattern of inheritance. This disease is present at birth, becomes symptomatic during early childhood, leads to inability to walk near the end of the first decade, and usually results in death by the end of the second decade. In this study, the extensor digitorum longus and soleus muscles from genetically dystrophic mice were examined at the electron microscopic level. The authors describe their results and discuss how these findings might provide some insight into one of the mechanisms of fiber necrosis in Duchenne muscular dystrophy.

Animals↗
PubMed1990

Significance of capillary basement membrane changes in diabetes mellitus.

Diabetes mellitus is a disease in which the capillary basement membranes are substantially altered. This diabetic microangiopathy is characterized by a thickening of the basement membrane and changes in its permeability characteristic due to a disturbance in the production and distribution of its functional components. Glucose metabolism and insulin imbalance have been implicated in these basement membrane modifications. The authors describe normal capillary basement membrane architecture and then discuss how pathologic changes caused by diabetes mellitus are related to diabetic foot pathology.

Basement Membrane↗
PubMed1987

Colocalization of prolactin and growth hormone within specific adenohypophyseal cells in male, female, and lactating female rats.

The localization of PRL and GH within adenohypophysial cells has been investigated with immunocytochemical methodology using colloidal gold of different sizes. Classically, using morphological criteria at the light and electron microscope levels, two types of individual cells have been described which, it is believed, exclusively produce either PRL or GH, i.e. mammotrophs and somatotrophs. Since it has been reported that some gonadotrophs may colocalize and secrete both FSH and LH, and that some unidentified cells release both PRL and GH, we designed a study to investigate whether PRL and GH are present only in their respective specific cells or may be colocalized in mammotrophs and somatotrophs or possibly other types of cells within the pars distalis. Using immunocytochemistry at the electron microscope level we were able to label the two hormones with different sizes of colloidal gold bound to a second antibody and visualize them within pituitary cells. Two different primary antibodies to PRL and GH as well as a more purified antibody to GH were used. Pituitaries from cycling and lactating female rats and adult males were processed appropriately for electron microscopic studies. After sectioning, individual grids were treated with either primary antibodies for PRL or GH, or the same grid was treated sequentially with these two antibodies. All primary antibodies were absorbed with the heterologous hormone before usage. The second antibodies were bound to colloidal gold particles of either 10 nm (for GH) or 20 nm (for PRL) diameter, so that selective visualization of the two hormones could be achieved within the same cells. It was observed that mammotrophs immunolabeled only for PRL, and somatotrophs labeled only for GH regardless of the source of the antibody. However, an atypical small granule cell, a possible mammosomatotroph, colabeled consistently for both PRL and GH in all types of animals used and with antibodies from all of above sources. This report gives for the first time morphological evidence for the existence of pituitary cells that colocalize both PRL and GH in the normal rat pituitary gland. The possibility that these bihormonal cells represent stem cells which may give rise to both mammotrophs and somatotrophs under appropriate stimulation or that they may release both hormones under the influence of unspecific stimuli is suggested.

Animals↗
PubMed1976

Serum alpha2-macroglobulin levels in tuberose sclerosis.

The serum levels of alpha2-macroglobulin (alpha2-MG) were determined by radial diffusion if fifty-four cases with tuberose sclerosis and compared with forty-seven institutionalised control subjects of similar age and sex distribution. Although higher levels of alpha2-MG were found in the females of both groups when compared with the males, this increase was not significant. The tuberose sclerosis subjects showed consistently elevated levels of alpha2-MG when compared to the control group for both the males and females separately and combined. With the two sexes combined this elevation was significant at p less than 0.001. The significance of this observation has been discussed both from the point of view of the possible mechanism involved and the use of this estimation in genetical counselling.

Adolescent↗
PubMed1975

Serum and tissue proteins in tuberous sclerosis. I. Serum and red-cell polymorphic systems.

5 serum protein polymorphic systems (haptoglobin, alkaline phosphatase, group-specific (Gc) proteins, beta2-glycoprotein 1 and leucine aminopeptidase) and 6 red-cell polymorphisms (adenosine deaminase, adenylate kinase, phosphoglucomutase, glutamic-pyruvic transaminase, phosphogluconate dehydrogenase and acid phosphatase) have been investigated in 54 subjects with tuberous sclerosis. The frequencies of all systems were compared with those of a control sample drawn from a similar mentally retarded population and abnormal distributions were detected in the haptoglobin and Gc system. Quantitative estimation of the serum levels of the Gc protein failed to detect any inter-group differences. Data on the deviations from the Hardy-Weinberg equlibrium, Haldane's Log ratio test between groups, and gene frequencies of both test and control groups are given. It is suggested that selection by mortality is the possible causation for the abnormal distribution of the Gc phenotypes, but the haptoglobin phenotype distribution requires further investigation with care being taken in the selection of control subjects.

Acid Phosphatase↗
PubMed1975

Hepatitis associated antigen and the ABO locus in Down's syndrome.

The recent observation by Arndt-Hansen et al. (1974) of increased frequency of blood group A over group O in blood donors positive for the hepatitis associated antigen has been investigated in Down's syndrome, in order to establish if this could account for the increased frequency of the antigen in that syndrome. Seventy-one of 227 subjects with Down's syndrome (31.3%) were found to be positive for the antigen by haemagglutination, and comparison of these with the HAA-subjects failed to reveal any differences in the ABO blood groups.

ABO Blood-Group System↗