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Biomedical subjects

R Watson

Publications and source records attributed to R Watson.

At least 145 records · Page 8Linked to original sources
PubMed1997

Partitioning of the Golgi apparatus during mitosis in living HeLa cells.

The Golgi apparatus of HeLa cells was fluorescently tagged with a green fluorescent protein (GFP), localized by attachment to the NH2-terminal retention signal of N-acetylglucosaminyltransferase I (NAGT I). The location was confirmed by immunogold and immunofluorescence microscopy using a variety of Golgi markers. The behavior of the fluorescent Golgi marker was observed in fixed and living mitotic cells using confocal microscopy. By metaphase, cells contained a constant number of Golgi fragments dispersed throughout the cytoplasm. Conventional and cryoimmunoelectron microscopy showed that the NAGT I-GFP chimera (NAGFP)-positive fragments were tubulo-vesicular mitotic Golgi clusters. Mitotic conversion of Golgi stacks into mitotic clusters had surprisingly little effect on the polarity of Golgi membrane markers at the level of fluorescence microscopy. In living cells, there was little self-directed movement of the clusters in the period from metaphase to early telophase. In late telophase, the Golgi ribbon began to be reformed by a dynamic process of congregation and tubulation of the newly inherited Golgi fragments. The accuracy of partitioning the NAGFP-tagged Golgi was found to exceed that expected for a stochastic partitioning process. The results provide direct evidence for mitotic clusters as the unit of partitioning and suggest that precise regulation of the number, position, and compartmentation of mitotic membranes is a critical feature for the ordered inheritance of the Golgi apparatus.

Cells, Cultured↗
PubMed1997

B-Myb function can be markedly enhanced by cyclin A-dependent kinase and protein truncation.

Transcription of the B-Myb gene is cell cycle regulated by an E2F-dependent mechanism and its product, B-Myb, is itself a transcription factor required for S-phase entry. Previously, we have shown that B-Myb is specifically phosphorylated during S-phase and that similar modification to a less electrophoretically mobile form could be induced by baculovirus-expressed cyclin A/Cdk2 kinase. We report here that cyclin A-mediated phosphorylation of B-Myb is associated with a marked increase in transactivation function in U-2 OS cells. In contrast to previous studies, transactivation of the luciferase reporter was dependent upon Myb binding sites located upstream of the promoter. Enhancement of B-Myb activation function was also obtained by truncation of the C-terminus just downstream of a domain conserved in evolution. Potentiation of B-Myb activity by phosphorylation was not simply a consequence of overcoming the negative effect of the C-terminus, however, as the truncated protein was to a lesser extent also activated by cyclin A/Cdk2. Whereas wild-type B-Myb transactivation activity could not be potentiated by cyclin A/Cdk2 in NIH3T3 cells, the truncated protein was hyperactive. Finally, we showed that B-Myb synergises with cyclin A to promote U-2 OS cells into S-phase.

3T3 Cells↗
PubMed1997

Feeding difficulty in elderly patients with dementia: confirmatory factor analysis.

The latent structure of feeding difficulty in elderly patients with dementia was investigated using multivariate statistical techniques including exploratory and confirmatory factor analysis. A survey design of 345 elderly patients with the diagnosis of dementia using a questionnaire completed by key workers and primary nurses, was used in local psychogeriatric and continuing care of the elderly facilities. Feeding difficulty and nursing intervention were estimated followed by fitting of latent variable models of feeding difficulty to the data using structural equation modelling. Three models of feeding difficulty in elderly patients with dementia, with 2, 3 and 4 factor structures respectively were compared. All three models showed a good fit to the data as assessed by several standard criteria. The 3 and 4 factor models, however, showed significantly better fit than the 2 factor model. The 4 factor model introduced a latent variable of "oral difficulty" with feeding which merits further investigation. This study demonstrates the possibility of developing reliable and validated scales for the assessment of feeding difficulty in elderly patients with dementia.

Aged↗
PubMed1997

The caring dimensions inventory (CDI): content validity, reliability and scaling.

Caring is an elusive phenomenon but this should not prevent the development and validation of reliable quantitative tools for studying this concept in large samples of nurses. The present paper reports on the content analysis of a questionnaire called the Caring Dimensions Inventory (CDI). The CDI was content validated in terms of existing conceptualizations of caring and research in this area and also in terms of a nursing taxonomy and its representation in popular United Kingdom nursing publications. The CDI was administered to a large sample of nurses working in Scotland and data were obtained from 1430 qualified and student nurses. The internal consistency of the CDI items related to perceptions of caring was established and the scalability of a sub-set of CDI items was demonstrated. The CDI scale was related to the constructs of age and sex of respondents. Possibilities for further analysis and development of the CDI are discussed.

Age Factors↗
PubMed1997

A longitudinal study of feeding difficulty and nursing intervention in elderly patients with dementia.

Structural equation modelling has already been used to study the relationship between feeding difficulty and nursing intervention in elderly people with dementia. Four models were tested and one provided an acceptable fit to the data. However, there were limitations in terms of sample size and the scales used to measure the variables related to feeding difficulty and nursing intervention. In the present study the sample size has been increased and the scaling of variables has been improved and an additional model has been tested. The best fitting model introduces a latent state variable to explain the relationship between feeding difficulty and nursing intervention. In order to study this relationship further several lines of investigation are suggested, including trait validation and state experimentation. These will be explained in the paper.

Aged↗
PubMed1997

Developmental enamel defects in tuberous sclerosis: a clinical genetic marker?

Ten probands with tuberous sclerosis (TS) and 20 first degree relatives were examined for evidence of pitted enamel hypoplasia; 100% of TS patients had pitting, compared to 65% of relatives and 72% of 25 controls. We found that 70% of TS cases had more than 14 pits per person compared with only 5% of relatives and 4% of controls; 85% of relatives and 84% of controls had fewer than six pits per person. Our results confirm that significantly increased numbers of dental enamel pits are found in persons with TS compared to controls. These results suggest that examination for the presence or absence of dental enamel pits is not a useful screening test for first degree relatives to detect otherwise unsuspected subjects with tuberous sclerosis. However, the lack of pits in first degree relatives in our study is probably largely because none of the relatives appeared to carry the TS gene.

Dental Enamel↗
PubMed1997

Anti-Ro(SS-A) antibody positive Sjögren's/lupus erythematosus overlap syndrome.

Unlike anti-Ro(SS-A) antibody positive subacute cutaneous lupus erythematosus (SCLE) patients, anti-Ro(SS-A) antibody positive lupus patients with Sjögren's syndrome (SS/LE) appear to have a more guarded prognosis. Our studies indicate these SS/LE patients have an increased frequency of pulmonary, neurological, and renal disease compared to SCLE patients.

Adolescent↗