PubMed Health⌕ Search

Biomedical subjects

E Watson

Publications and source records attributed to E Watson.

At least 19 recordsLinked to original sources
PubMed1992

High-performance anion-exchange chromatography of asparagine-linked oligosaccharides.

Oligosaccharides released enzymatically by N-glycanase from fetuin, alpha-acid glycoprotein, human chorionic gonadotropin, platelet-derived growth factor, and kallikrein were chromatographed on a polymeric pellicular anion-exchange column at pH values of 5 and 13. Separations occurred into groups of peaks containing the same number of sialic acids with an additional separation dependent upon the nature of the antennary structure present. High pH conditions were required for the optimum separation of fetuin oligosaccharides, while low pH conditions significantly improved resolution of oligosaccharides obtained from the other glycoproteins. The analytical separation of oligosaccharides under conditions of low pH has important implications in the development of chromatographic mapping and identification techniques for N-linked oligosaccharides present on recombinant proteins.

Animals↗
PubMed1992

Multiple peak formation from reversed-phase liquid chromatography of recombinant human platelet-derived growth factor.

Reversed-phase liquid chromatography of recombinant platelet-derived growth factor (PDGF) results in the appearance of at least four distinguishable peaks. The relative areas of these peaks are, in part, dependent upon the gradient time and the temperature. Isolation and reinjection of each peak gave chromatographic profiles comparable to that obtained from unfractionated PDGF. Increasing the temperature above 60 degrees C resulted in a single peak that, when isolated and reinjected at ambient temperature, produced a chromatogram comparable to PDGF which had not been exposed to elevated temperature. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that all four peaks had the same molecular mass as PDGF and were active as determined by a PDGF mitogenic bioassay. These results indicate that multiple conformations of PDGF are present and we postulate that their appearance may be a result of isomeric structures arising from the presence of Pro-Pro bonds within the primary structure of the protein.

Amino Acid Sequence↗
PubMed1992

Interactions between CD4+ T-cells and rat Schwann cells in vitro. 1. Antigen presentation by Lewis rat Schwann cells to P2-specific CD4+ T-cell lines.

Interactions between CD4+ P2-specific T-cell lines and Schwann cells were examined in vitro by scanning electron microscopy (SEM) and T-cell proliferation studies. CD4+ T-cell lines clustered around and attached to Schwann cells which expressed Major histocompatibility complex (MHC) class II molecules. Only those P2-specific T-cell lines capable of inducing experimental allergic neuritis (EAN) when injected into adult Lewis rats clustered around the Schwann cells. T-cell lines responsive to P2 but not able to induce EAN did not cluster around Schwann cells. The addition of exogenous P2 protein inhibited in a dose-dependent way clustering and proliferation of the P2-specific T-cell lines. Cytoplasmic P2 was detected in Schwann cells by immunofluorescent labelling and the results of proliferation assays in this study suggest that endogenous P2 protein was processed by the Schwann cells and presented to T-cell lines in association with MHC class II molecules. The clustering and proliferation of class II-restricted CD4+ P2-specific T-cell lines in the presence of Schwann cells provides evidence for a role for Schwann cells as facultative antigen presenting cells, processing and presenting 'self' endogenous antigen to CD4+ T-cell lines capable of inducing EAN.

Animals↗
PubMed1990

Human oral epithelial cell culture I. Improved conditions for reproducible culture in serum-free medium.

Gingival tissue from healthy adult human donors was used as a source of epithelial cells for culture. An overnight incubation of this tissue with dispase facilitated the mechanical separation of the surface epithelium from the underlying fibrous connective tissue. This step minimized culture contamination with fibroblasts. The epithelium was then trypsinized to prepare a single cell suspension. The cell pellets were collected by centrifugation and resuspended in keratinocyte growth medium, incubated at 37 degrees C and 5% CO2 in a humid atmosphere. Primary cultures grew in small islands that coalesced at confluency. Immunohistochemistry demonstrated uniform staining of the cells with antibodies to keratins of stratified squamous epithelium. Ultrastructurally, the cells contained distinct intermediate filaments. When cells were grown in media with low calcium (0.15 mM), cell-to-cell contacts were via interlacing papillary projections with no desmosomes. However, when cells were grown under physiologic calcium (1.2 mM), desmosomes were prominent and well developed. Cells were maintained in culture for over 100 d (7 passages).

Adult↗
PubMed1989

Community attitudes to cystic fibrosis carrier testing in England: a pilot study.

Inexpensive and accurate carrier testing for cystic fibrosis (CF) will be possible in the near future. There are no existing studies on the attitudes of English persons in the community to carrier testing for CF or any other recessive disorder. We have conducted a trial study of 166 persons at two schools, two doctors' surgeries, and a family planning clinic. Only a minority had clear pre-existing knowledge of cystic fibrosis and its genetic nature. However, over 80 per cent of those questioned expressed interest in knowing their carrier status. Although it is well known that uptake can only be assessed when a service is in place, and while further studies are required to confirm that testing will be of interest to couples of reproductive age with no previous knowledge of CF, the data strongly suggest that there will be interest in community-wide testing for CF carrier status when such a test becomes available in the United Kingdom.

Attitude to Health↗
PubMed1989

Macroscopic, microscopic and ultrastructural findings in experimental haemarthrosis of rhesus monkeys.

The effects of a single episode of massive haemarthrosis in rhesus monkeys were studied morphologically. Autologous whole blood was injected into a femorotibial joint of 16 anaesthetized monkeys, equally divided into four groups and killed 7 days, 2, 3 and 6 months post injection (PI). Synovial membrane and articular cartilage were examined for macroscopic, microscopic and ultrastructural changes. Haemarthrosis was only evident in one monkey by 7 days PI. Slight yellow-brown discoloration of synovium and cartilage was evident in groups killed early after injection. Histologically, a hyperplastic and inflammatory reaction was present in the synovium at 7 days PI. Ultrastructural examination of synoviocytes in this group revealed numerous cytoplasmic vacuoles and prominent microplicae compatible with increased phagocytic activity. Erythrophagocytosis by synoviocytes was observed by light microscopy and confirmed by transmission EM. Results of scanning EM suggested that red cells might also pass through the synovial intima. Transmission EM also revealed mild degenerative changes in superficial chondrocytes. Rhesus monkeys reacted morphologically to haemarthrosis in the same way as dogs and rabbits, with mild morphological changes that resolved by 2 months PI.

Animals↗
PubMed1989

Screening infants for hearing loss.

A computerised child health register was used to study the coverage, referral rate, and false positive rate of the eight month hearing distraction test in a cohort of 1990 births to residents of one district during an eight month period. Coverage by the age of 9 months was under 60% and varied with ethnic group and immunisation record. The true problem rate among those referred was 48%. None of the three children in the cohort who had a sensorineural hearing loss was picked up by screening, although it did identify children with conductive loss. The findings question the value of the distraction test as currently used, and underline the usefulness of computerisation, even if limited to child registration, in the evaluation of screening tests.

Adolescent↗
PubMed1989

The health visitor's visit.

A study was undertaken to see how closely 100 clients' views of the purpose of the health visitor's home visit were in accord with the professionals' views. It was found that overall clients' views of the purposes of the health visitor's visit were in general agreement with the professionals' view. However the satisfaction with the visit felt by professionals and client did not depend on the closeness of agreement of their views on the reasons for the visit.

Community Health Nursing↗
PubMed1988

High-performance size-exclusion chromatography of recombinant derived proteins and aggregated species.

The chromatographic behavior of some recombinant derived proteins and aggregated species was studied using high-performance size-exclusion chromatography (HPSEC). At neutral pH values, monomeric proteins exhibited non-ideal behavior while aggregated species were not eluted. As the pH was lowered below 5, both aggregated and monomeric species were eluted, with the amount of aggregated species increasing with decrease in pH. Final elution conditions selected for the simultaneous chromatography of monomeric and aggregated proteins were 0.1 M orthophosphoric acid, pH 2.5. The utility of the system was evaluated by determining the rates of protein degradation at elevated temperatures and comparing the results with those obtained using standard bioassay procedures. The rate of formation of aggregated species was also determined by HPSEC and corresponded to the rate of degradation of monomeric protein. The use of HPSEC with low pH eluent provides a rapid means for estimating protein stability under accelerated temperature conditions as well as for determining the existence and formation of aggregated species.

Chromatography, Gel↗
PubMed1987

Expectancy, redefinition and reported pain.

Three groups of subjects were administered a redefinition strategy which asked them to focus on sensations during noxious stimulation. Those in one group were informed that the strategy would reduce pain (positive expectancy), those in a second were informed that it would augment pain (negative expectancy), and those in a third were given no information on expectancy. Subjects in a fourth group received neither redefinition nor instructions on expectancy. The four groups did not differ either in expectancy of pain reduction or in reduction of reported pain. Subjects in all groups expected more pain than they reported, and expectations for pain reduction showed only a small correlation with degree of reported pain reduction. In all groups, men reported less pain than women.

Adult↗
PubMed1986

First-trimester prenatal diagnosis of cystic fibrosis with linked DNA probes.

Linkage analysis with cloned gene probes has shown that the mutation causing cystic fibrosis is located in the middle of the long arm of chromosome 7. First-trimester diagnosis of cystic fibrosis is reported in four informative families and second-trimester diagnosis in one family with fetal DNA prepared from chorionic villi, hybridised with the tightly linked DNA probes, pJ3.11 and met. Risk calculations show that the expected false-negative and false-positive rates are approximately 2% and 6%, respectively, for typical nuclear families with one affected living child. Existing probes are sufficiently informative to allow full diagnosis in about two-thirds of couples presenting with at least one affected child. In half of the remainder, the inheritance of one parental mutant chromosome can be deduced.

Biopsy↗