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Biomedical subjects

R E Ellis

Publications and source records attributed to R E Ellis.

At least 19 recordsLinked to original sources
PubMed1992

Caenorhabditis elegans gene ced-9 protects cells from programmed cell death.

The gene ced-9 of the nematode Caenorhabditis elegans acts to protect cells from programmed cell death. A mutation that abnormally activates ced-9 prevents the cell deaths that occur during normal C. elegans development. Conversely, mutations that inactivate ced-9 cause cells that normally live to undergo programmed cell death; these mutations result in embryonic lethality, indicating that ced-9 function is essential for development. The ced-9 gene functions by negatively regulating the activities of other genes that are required for the process of programmed cell death.

Animals↗
PubMed1992

Dysphagia in cerebral palsy: a comparative study of the Exeter Dysphagia Assessment Technique and a multidisciplinary assessment.

Eighteen children with cerebral palsy in a special school, most of whom had feeding difficulties, were studied to compare the diagnostic value of the Exeter Dysphagia Assessment Technique (EDAT) with an exhaustive clinical assessment undertaken by a multidisciplinary team experienced in the diagnosis and treatment of dysphagia of neurological origin. Four feeding skills were assessed by each method independently, viz. anticipation, intraoral sensory perception, oral-motor efficiency, and pharyngeal triggering. Comparison of the two sets of results showed agreement in at least 78% of the assessed skills. The possible reasons for the few discrepancies are discussed. The noninvasive EDAT equipment was easy to use with the children, who had a range of type and severity of cerebral palsy. The test was undertaken in their familiar surroundings and took 15 to 20 min per child. Interpretation of the results showed that EDAT provided a rapid, reliable diagnostic aid which assisted in the assessment of the degree of feeding impairment within each of the four feeding skills tested.

Adolescent↗
PubMed1992

Negative regulators of programed cell death.

During animal development many cells undergo programed deaths. Recently, genes that suppress the cell-death program have been described in both vertebrates and invertebrates. These genes play a vital role in regulation of the molecules that kill cells, and disruption of this regulatory process can contribute to disease.

Animals↗
PubMed1991

High-resolution magnetic resonance imaging of the interphalangeal joints of the hand.

High-resolution magnetic resonance imaging (MRI) of the interphalangeal joints of the fingers is being employed to study arthritis. To facilitate this research, a clear understanding of the structures visualisable by MRI is necessary. A gradient echo (GE) sequence was developed that produced good contrast between cartilage and other joint structures. These detailed images, with an in-plane resolution of 200 x 100 microns, enable resolution of three cartilage zones which can be interpreted as a superficial layer at the cartilage/cartilage interface, an intermediate layer and calcified cartilage in contact with bone; these correlate well with known anatomy. Further analysis of the images indicates that although a chemical shift artifact causes changes in the images at the field strength used (0.5 T), it does not cause enough distortion to necessitate suppression of the effect. Furthermore, the only detectable susceptibility artifact at these low field strengths was a loss of signal in bone trabeculae at the bone/cartilage interface. There is clearly potential in the study of the articular structures, in particular cartilage, in detail, using high-resolution MRI.

Adult↗
PubMed1991

Genes required for the engulfment of cell corpses during programmed cell death in Caenorhabditis elegans.

After programmed cell death, a cell corpse is engulfed and quickly degraded by a neighboring cell. For degradation to occur, engulfing cells must recognize, phagocytose and digest the corpses of dying cells. Previously, three genes were known to be involved in eliminating cell corpses in the nematode Caenorhabditis elegans: ced-1, ced-2 and nuc-1. We have identified five new genes that play a role in this process: ced-5, ced-6, ced-7, ced-8 and ced-10. Electron microscopic studies reveal that mutations in each of these genes prevent engulfment, indicating that these genes are needed either for the recognition of corpses by other cells or for the initiation of phagocytosis. Based upon our study of double mutants, these genes can be divided into two sets. Animals with mutations in only one of these sets of genes have relatively few unengulfed cell corpses. By contrast, animals with mutations in both sets of genes have many unengulfed corpses. These observations suggest that these two sets of genes are involved in distinct and partially redundant processes that act in the engulfment of cell corpses.

Animals↗
PubMed1991

Two C. elegans genes control the programmed deaths of specific cells in the pharynx.

The genes ces-1 and ces-2 control the decisions of two cells in the nematode Caenorhabditis elegans to undergo programmed cell death. Mutations that cause a gain of ces-1 function or a reduction of ces-2 function prevent these cells, the sisters of the two pharyngeal NSM neurons, from dying. These mutations do not affect most other cell deaths. Genetic studies indicate that ces-1 and ces-2 affect the fates of the NSM sisters by regulating the genes required for all programmed cell deaths to occur.

Animals↗
PubMed1990

The Exeter Dysphagia Assessment Technique.

The Exeter Dysphagia Assessment Technique (EDAT) uses noninvasive equipment to record, simultaneously, "feeding respiratory patterns," the time drink entered the mouth, and associated swallow sounds during feeding. The easily portable equipment enabled patients' swallowing ability to be tested, at the bedside if necessary, using a small amount of fruit-flavored drink. The results appear in chart form. EDAT findings from groups of normal subjects aged 2-90 years were compared with those from patients with dysphagia of neurologic origin and normal subjects under experimental feeding conditions. The results revealed maturation of the feeding respiratory pattern in the teenage years and remarkable consistency thereafter. Differences in the recordings between the normal and abnormal subjects were sufficiently marked to allow the findings to be used in the diagnosis of other patients with dysphagia of doubtful neurologic cause. Interpretation of the charts and recorded timings of the oral and pharyngeal stages of swallowing permitted a more accurate identification of sensory nerve, motor nerve, and functional involvement causing dysphagia of neurologic origin and may be used as a guide to the origin of the sensory deficit.

Adolescent↗
PubMed1990

Demonstration of a geode by magnetic resonance imaging: a new light on the cause of juxta-articular bone cysts in rheumatoid arthritis.

The magnetic resonance imaging (MRI) features of a rheumatoid arthritic geode are presented. Development of such a cyst from before x ray diagnosis to its coalescence with the wrist joint is described. The evidence suggests that these juxta-articular cysts are not merely an intrusion of the synovial cavity into the bone marrow but start as isolated structures beneath the subchondral bone.

Adult↗
PubMed1990

Coordination of sucking, swallowing and breathing in the newborn: its relationship to infant feeding and normal development.

Non-invasive, sensitive equipment was designed to record nasal air flow, the timing and volume of milk flow, intraoral pressure and swallowing in normal full-term newborn babies artificially fed under strictly controlled conditions. Synchronous recordings of these events are presented in chart form. Interpretation of the charts, with the aid of applied anatomy, suggests an hypothesis of the probable sequence of events during an ideal feeding cycle under the test conditions. This emphasises the importance of complete coordination between breathing, sucking and swallowing. The feeding respiratory pattern and its relationship to the other events was different from the non-nutritive respiratory pattern. The complexity of the coordinated patterns, the small bolus size which influenced the respiratory pattern, together with the coordination of all these events when milk was present in the mouth, emphasise the importance of the sensory mechanisms. The discussion considers (1) the relationship between these results, those reported by other workers under other feeding conditions and the author's (WGS) clinical experience, (2) factors which appear to be essential to permit conventional bottle feeding and (3) the importance of the coordination between the muscles of articulation, by which babies obtain their nourishment in relation to normal development and maturation.

Child Development↗
PubMed1989

Respiratory patterns associated with swallowing: Part 1. The normal adult pattern and changes with age.

Simple, non-invasive equipment was designed to record respiratory patterns associated with swallowing food or drink in young and elderly healthy adults, to compare with neurologically impaired patients who complained of dysphagia. The timing of the entry of the test drink from a spoon into the mouth, the swallow event and respiration were recorded electronically and were presented in chart form. The equipment proved to be easy to use and the results were consistent. All 33 subjects showed a well-defined respiratory pattern, with individual minor variations, but different from the pattern of their resting respiration. The direction of respiration during spoon contact was consistent for each individual and the pharyngeal stage of swallowing was almost always followed by a large expiration. Thus the resting respiration is not simply arrested during swallowing, but is substituted by a different, well-controlled pattern.

Adult↗
PubMed1989

Respiratory patterns associated with swallowing: Part 2. Neurologically impaired dysphagic patients.

The co-ordination of respiration and swallowing was recorded electronically in three groups of patients who complained of dysphagia following a stroke, or associated with multiple sclerosis or motor neurone disease. The test used was simple and the equipment easily taken to the patient, in bed if necessary. All the patients showed differences from normal subjects and there were differences between each of the neurologically impaired groups. The technique appears to allow an assessment of the state of oropharyngeal motor and sensory functions separately during swallowing.

Adolescent↗
PubMed1987

The effect of tongue position on division of airflow in the presence of velopharyngeal defects.

Results of studies of nasal to oral airflow ratios are reported using simple and accurate anatomical models to record the effect of differing positions of lips, tongue and soft palate, with particular reference to the effect of the position of the dorsum of the tongue and various sizes of velopharyngeal defect. The resistances to airflow produced by the labial, palatolingual, velopharyngeal and naral valves were found to be interdependent. Variations in tongue position alone could allow the same nasal airflow during a more than three-fold variation in the size of velopharyngeal defects. The degree of nasal escape of air which is responsible for the typical "cleft palate" type of speech cannot be assessed by observation of the size of the velopharyngeal defect alone.

Cleft Palate↗
PubMed1986

The rDNA of C. elegans: sequence and structure.

We have sequenced one complete rDNA tandem repeat from the nematode C. elegans. By comparative analysis we derive secondary structures for the 18s, 5.8s, and 26s rRNA molecules, and comment on other important features of the sequence. We also present the sequence of a junction between the rDNA and non-ribosomal DNA. Finally, we use our data to quantify the evolutionary relationships among several organisms currently studied in developmental biology.

Base Sequence↗