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Biomedical subjects

A H Marshall

Publications and source records attributed to A H Marshall.

At least 19 recordsLinked to original sources
PubMed2006

Individual and multi-environment combined analyses identify QTLs for morphogenetic and reproductive development traits in white clover (Trifolium repens L.).

White clover (Trifolium repens L.) is a key component legume of temperate pasture agriculture and an important target for molecular marker-assisted plant breeding. A genetic map of white clover has been used to assess genetic control of agronomically important traits that vary in the F2(I.4RxI.5J) mapping family. Phenotypic analysis was performed for a range of vegetative morphogenesis traits (such as leaf area, internode length, plant height and plant spread) and reproductive morphogenesis and development traits (such as flowering date, floral intensity and seed yield), with both spatial and temporal replication. A multi-environment combined analysis (combined analysis) has been performed for traits assessed across multiple experimental datasets in order to identify consistent genetic effects. Quantitative trait locus (QTLs) were detected for the majority of traits, and the locations and magnitudes of QTL effects were compared between individual and combined analyses. This molecular genetic dissection of agronomic traits in white clover provides the basis for equivalent studies in more complex populations, design of marker-assisted selection strategies and comparative genetics with model legume species. Selection for QTLs derived from the combined analysis will permit robust improvement of phenotypic traits over different environments.

Chromosome Mapping↗
PubMed2005

Cochlear implantation in cochlear otosclerosis.

OBJECTIVES/HYPOTHESIS: The objective was to correlate implant performance in cochlear otosclerosis to 1) matched control samples, 2) severity of otic capsule involvement, 3) prior ipsilateral surgery, and 4) programming issues. STUDY DESIGN: Retrospective case controlled study. METHODS: Study cohort comprised 30 individuals. Diagnosis was based on prior ear surgery (stapedectomy [n = 18] or fenestration [n = 2]) and/or pathognomonic radiological findings. High-resolution computed tomography images of the temporal bones were assessed by two radiologists and graded (range, 0-3) for the extent of otosclerosis. Operative records were reviewed. Performance, programming visits, and the number of electrode deactivations at 6 months and at 1 year after implantation were determined for the individuals with otosclerosis and compared with a group of matched control subjects. A within-group comparison correlating severity of otosclerosis to the above was carried out. RESULTS: Implant performance in individuals with cochlear otosclerosis was not significantly different from those without. Previous surgery on the side of implantation did not alter performance. Programming difficulty as reflected in the number of visits and electrode deactivation for sound quality reasons were comparable. Deactivation for facial nerve stimulation occurred exclusively in otosclerotics with the most severe radiological disease (grade 3) and was only with non-modiolar hugging electrodes (n = 5). There was no observed difference between the radiological extent of otosclerosis and implant performance. CONCLUSION: Individuals with severe otosclerosis considering cochlear implantation can be counseled to expect similar benefit to those without, regardless of whether prior surgery occurred on the side of implantation or of severity of otic capsule involvement. There is a significant risk of facial nerve stimulation in otosclerotics with grade 3 disease.

Case-Control Studies↗
PubMed2004

Restoration of the impacted nasal pyramid using a Kirschner wire.

One of the most challenging types of nasal fracture is when the nasal pyramid, comprising of the upper and lower lateral cartilages and septum including the vomer, is fractured, impacted and has rotated into the face. This paper describes a technique to elevate the nasal complex and hold it forwards using a Kirschner wire.

Adult↗
PubMed2004

Principles of septal correction.

The operation of septoplasty is often given to junior surgeons to perform and dismissed as a simple procedure. This can lead to unsatisfactory results with unnecessary morbidity for the patient and disillusionment for the surgeon. Trainee surgeons feel that the operation of septoplasty is poorly taught. Some common problems encountered during septal surgery are described and a variety of surgical solutions are offered.

Cartilage↗
PubMed2002

Modelling patient duration of stay to facilitate resource management of geriatric hospitals.

A fundamental aspect of health care management is the effective allocation of resources. This is of particular importance in geriatric hospitals where elderly patients tend to have more complex needs. Hospital managers would benefit immensely if they had advance knowledge of patient duration of stay in hospital. Managers could assess the costs of patient care and make allowances for these in their budget. In this paper. we tackle this important problem via a model which predicts the duration of stay distribution of patients in hospital. The approach uses phase-type distributions conditioned on a Bayesian belief network.

Aged↗
PubMed2002

More siblings, less hay fever: more evidence.

The prevalence of allergic rhinitis is increasing. Many authors have noted the prevalence of hay fever is less in children from large families and the 'hygiene hypothesis' has been suggested as an explanation. We looked at the association of sibling number and other variables on the prevalence of hay fever and perennial rhinitis. From 26100 households selected at random, 34362 questionnaires were returned from individuals over 14 years of age; 19.3% had symptoms of hay fever and a further 6.0% had symptoms of perennial rhinitis. A logistic regression analysis showed that for individuals with two or more siblings, the odds of suffering from hay fever are less than the odds for people with no siblings and that these odds decrease as the number of siblings increases. This effect was not found in subjects with perennial rhinitis. This study adds weight to the 'hygiene hypothesis'.

Adolescent↗
PubMed2001

Force distributions in three-dimensional granular assemblies: effects of packing order and interparticle friction.

We present a systematic investigation of the distribution of normal forces at the boundaries of static packings of spheres. A method for the efficient construction of large hexagonal-close-packed crystals is introduced and used to study the effect of spatial ordering on the distribution of forces. Under uniaxial compression we find that the form for the probability distribution of normal forces between particles does not depend strongly on crystallinity or interparticle friction. In all cases the distribution decays exponentially at large forces and shows a plateau or possibly a small peak near the average force but does not tend to zero at small forces.

Journal Article↗
PubMed2001

Developing a Bayesian belief network for the management of geriatric hospital care.

Resource management is an essential feature of hospital management. This is especially true for geriatric services, as older people often have complex medical and social needs. Hospital management should benefit from an explanatory model that provides predictions of duration of stay and destination on discharge. We describe how a Bayesian belief network models the behaviour of geriatric patients using predictive variables: personal details, admission reasons and dependency levels. This approach is illustrated using data on 4,722 patients admitted to geriatric medicine at St. George's Hospital, London; distributions of the patient outcome given typical values of the predictive variables are provided.

Aged↗
PubMed2001

The development of a General Nasal Patient Inventory.

Most available clinical outcome measures for rhinology patients relate to specific nasal disease or general quality of life. Fairley's validated 12-item questionnaire measures general nasal symptoms, but is a 'physician-derived' clinical tool and may not reflect all the problems that rhinology patients experience. Our aims were to develop a patient-orientated questionnaire, representing the concerns of a large number of rhinology patients, called the General Nasal Patient Inventory (GNPI) and compare this with the Fairley nasal questionnaire (FNQ). The GNPI was developed from the open-ended problem lists of 211 rhinology patients, from the 45 most frequent complaints. Both questionnaires were then administered to 153 general rhinology patients and the results compared. The highest-ranking items for each questionnaire were different, but the total scores were highly correlated (r = 0.79, P < 0.0001). Factor analysis showed six factors to account for 75% of FNQ variance and 18 factors for 78% of GNPI variance. The 45-item GNPI, the first patient-derived, comprehensive nasal questionnaire could be a time-saving tool in rhinology clinics and more sensitive to change after intervention than other available measures.

Adolescent↗
PubMed2001

CSF rhinorrhoea: the place of endoscopic sinus surgery.

Cerebrospinal fluid (CSF) rhinorrhoea has been managed by both neurosurgeons and otorhinolaryngologists, with neurosurgeons often choosing an intracranial approach and otorhinolaryngologists an extracranial approach. Recently, transnasal endoscopic techniques have been introduced that significantly reduce the morbidity of surgical repair when compared with previous techniques. The sense of smell was preserved in all patients who underwent an endoscopic repair of their CSF leak where it was present preoperatively. The results of transnasal endoscopic repair now make it the treatment of choice for most anterior cranial and sphenoid CSF leaks, with the exception of defects in posterior wall of the frontal sinus or defects larger than 5 cm. It is vital that a diagnosis of a CSF leak is confirmed by immunofixation of beta 2 transferrin as unilateral rhinorrhoea can masquerade as a CSF leak. We illustrate our experience with 78 patients who were referred with a diagnosis of CSF rhinorrhoea.

Adult↗
PubMed2001

Endoscopic management of basal encephaloceles.

Encephaloceles have been traditionally treated by a transcranial or external approach. The advent of endoscopic sinus surgery has allowed a new intranasal approach for the treatment of basal encephaloceles, minimising patient morbidity. We discuss the classification and presentation of encephaloceles, and present our experience in the repair of six cases. We believe transnasal endoscopic repair is the method of choice in dealing with selected basal encephaloceles.

Adult↗
PubMed2000

Osteomyelitis of the frontal bone secondary to frontal sinusitis.

Osteomyelitis of the frontal bone is becoming an increasingly rare complication of frontal sinusitis. We present seven cases that represent the largest series published in the last 50 years. Three cases were associated with intracranial involvement. Osteomyelitis should enter the differential diagnosis when there is a fluctuant swelling on the scalp, or if there is a discharging fistula. Treatment requires aggressive surgery to remove all sequestra in combination with long-term antibiotic therapy. Intracranial complications should be excluded by imaging and treated simultaneously if present.

Adolescent↗
PubMed1999

An algorithm for the management of CSF rhinorrhoea illustrated by 36 cases.

The diagnosis of cerebrospinal fluid (CSF) rhinorrhoea should be established beyond reasonable doubt before surgical intervention is embarked upon. It is important not to miss the diagnosis in view of the real potential complication of meningitis if it is left untreated. We describe a management algorithm which centers around the selective use of nasal endoscopy, immunofixation of beta2 transferrin, high resolution coronal CT scans, and fluorescein lumbar puncture. This management strategy is illustrated with 36 cases. We have developed a minimally invasive endoscopic technique to repair CSF leaks, and in 30 patients we had a success rate of 93% after one procedure.

Adolescent↗
PubMed1988

Modulation of nuclear proto-oncogene expression and cellular growth in myeloid leukemic cells by human interferon alpha.

To address the mechanisms that regulate expression of specific growth-related nuclear proto-oncogenes, the transcript levels of the c-fos, c-myc, (2'5')-oligoadenylate synthetase, IFN-alpha 1, and IFN-beta 1 genes have been measured in the human leukemic cell lines KG-1, U937, and HL-60 following growth stimulation by serum, induction of differentiation by tumor-promoting agents, and/or treatment of cells with exogenously supplied alpha interferon (rIFN-alpha 2). Production of fos and myc RNA was measured by S1 mapping, using fos DNA probes which identified either primary unspliced transcripts or steady-state-spliced mRNA levels, and using a myc probe which spanned the two major c-myc start sites, P1 and P2. Pretreatment of a quiescent KG-1 cell population with IFN for 18 hours before serum addition decreased the stimulation of both fos and myc RNA production. In HL-60 and U937 cells, IFN pretreatment had no inhibitory effect on serum-induced fos or myc transcription; however, in U937, rIFN-alpha 2 treatment alone stimulated fos mRNA 11-fold. Expression of 2'5'oligoadenylate synthetase was induced in IFN-treated cultures but not in cells stimulated with serum alone. No serum-induced IFN-alpha 1 or IFN-beta 1 gene expression was observed in KG-1 or U937 cells. These results demonstrate that exogenous rIFN-alpha 2 treatment of quiescent KG-1 cells can antagonize the effect of growth factors by altering expression of nuclear proto-oncogenes, but in general growth inhibition is not obligatorily coupled to inhibition of proto-oncogene transcription.

Cell Division↗
PubMed1986

Transcutaneous electrical nerve stimulation following appendicectomy: the placebo effect.

A controlled trial was undertaken to compare the efficacy of transcutaneous electrical nerve stimulation (TENS) with standard intramuscular opiate analgesia in the management of postoperative pain following appendicectomy. Consecutive patients undergoing emergency appendicectomy were randomised into control, sham TENS and active TENS groups. There was a significant decrease in pain severity and analgesic intake in both active and sham TENS groups when compared with the control group (P less than 0.01). No difference was demonstrated in pain severity between active and sham TENS groups but the active TENS group required slightly less analgesia. These results suggest that the major benefit of TENS in the postappendicectomy patient is due to its 'placebo effect' and its use in this situation cannot be recommended.

Adolescent↗
PubMed1976

A critique and case study of nodular sclerosing Hodgkin's disease.

This paper presents a critique of the present concepts of the pathology of nodular sclerosing Hodgkin's disease and particularly of the criteria required for diagnosis for the condition and its separation from other types of Hodgkin's disease. In addition, the natural history and histopathology of the condition have been studied among 104 cases of Hodgkin's disease presenting at The London Hospital, and the significance of the appearance is discussed.

Adult↗