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Biomedical subjects

Richard Morris

Publications and source records attributed to Richard Morris.

28 records · Page 2Linked to original sources

Neural connections that compute.

The UK's Foresight Cognitive Systems Project brings together researchers in the life sciences and physical sciences to see where they can learn from one another and to debate, and plan, the future of research in cognitive systems. The project, a part of the UK government's Foresight initiative, sets out to identify potential opportunities for the economy or society from new science and technology. Through a series of research reviews, the project has created 'snap shots' of research in cognitive systems. A major conference in Bristol in September will consider series of research manifestos created by interdisciplinary groups.

Cognition↗

The influence of peripheral vascular disease on the carotid and femoral wall mechanics in subjects with abdominal aortic aneurysm.

AIM: Aortic and carotid stiffness is elevated in patients with abdominal aortic aneurysm (AAA). Peripheral vascular disease (PVD) frequently coexists with AAA and may further impair the arterial wall mechanics and increase the cardiovascular load. We therefore studied the elastic carotid and muscular femoral biomechanical properties and intima-media thickness (IMT) in this group of patients. METHODS: The elastic indices and IMTs of the common carotid and common femoral arteries were determined in 30 patients with AAA (15 with PVD) with a duplex scanner coupled with a wall tracking system. Fasting plasma creatinine level, glucose and lipid concentrations, and their physiologic variables known to influence the arterial wall mechanics were also assessed. RESULTS: Patients with AAA and PVD have significantly stiffer carotid (Petersen's elastic modulus, 2207 +/- 905 mm Hg versus 1268 +/- 432 mm Hg; P =.001; stiffness index, 22.73 +/- 9.63 versus 12.60 +/- 4.24; P =.001] and femoral (Petersen's elastic modulus, 4906 +/- 4057 mm Hg versus 2599 +/- 1169 mm Hg; P =.043; stiffness index, 49.02 +/- 40.04 versus 26.07 +/- 13.22; P =.044) arteries than subjects with AAA alone. Although patients with PVD have thicker carotid and femoral IMTs, no statistical difference was seen between the two groups. The subjects were matched for age, body mass index, heart rate, systolic and diastolic blood pressures, total vascular risk score, plasma creatinine level, and fasting lipid and glucose concentrations. CONCLUSION: Subjects with PVD and AAA have significantly stiffer carotid and femoral arteries, which may indicate increased cardiovascular load and may account for the highest mortality rate seen in these patients in the UK Small Aneurysm Trial. Therefore, treatment of associated cardiovascular risk factors is important and may have to be tailored on an individual basis according to the findings of the arterial wall mechanics.

Aged↗

Hysterectomy: surgical route and complications.

OBJECTIVES: To compare the morbidity associated with abdominal, vaginal and laparoscopic hysterectomies in a group of patients suitable for anyone of these surgical routes. STUDY DESIGN: Retrospective analysis of 1000 consecutive hysterectomies. RESULTS: The 513 patients were deemed to be suitable for hysterectomy by anyone of the three surgical routes. The overall complication rates were 34, 24 and 21% for abdominal, vaginal and laparoscopic hysterectomy, respectively. Multiple regression analysis showed that the morbidity was similar when confounding factors were allowed for, in particular the use of peri-operative antibiotics. CONCLUSIONS: The route of hysterectomy is not a major determining factor of peri-operative complications when other confounding variables are taken into account.

Anti-Bacterial Agents↗

Orexins and feeding: special occasions or everyday occurrence?

Neurons expressing prepro-orexin, the precursor of orexin-A and -B, are found in the lateral hypothalamic area, a region classically implicated in driving feeding. Orexin-A induces feeding transiently when injected centrally, and food intake can be decreased when orexin action is disrupted by immunoneutralization of orexin-A, or by pharmacological blockade of orexin receptors, or by transgenic knockout of orexin. Here, we argue that orexin neurons may act to stimulate feeding in the short term, and that important regulatory signals may be a fall in plasma glucose (stimulatory), countered by satiety signals generated by eating, such as gastric distention (inhibitory).

Animals↗

Impaired carotid and femoral viscoelastic properties and elevated intima-media thickness in peripheral vascular disease.

BACKGROUND: We undertook a study to determine whether peripheral vascular disease of the lower extremity (PVD) per se affects the arterial viscoelastic properties and intima-media thickness (IMT) of the carotid and femoral arteries. METHODS: Thirty-five patients with PVD, 35 age- and gender-matched control subjects were examined with ultrasound scan wall tracking system, with the simultaneous measurement of blood pressure for carotid and femoral IMT and viscoelastic properties. RESULTS: Subjects with PVD have significantly impaired carotid elastic properties including compliance (mean (SD): 6.50 (2.39) vs 9.93 (4.07) %mmHg(-1)x10(-2), P<0.001), Petersen's elastic modulus (1.77 (0.69) vs 1.19 (0.63) mmHg x 10(3), P=0.001) and stiffness index (17.92 (7.21) vs 12.10 (6.17), P=0.001) when compared to non-PVD controls. They also have significantly altered femoral elastic properties including Petersen's elastic modulus (5.94 (4.98) vs 3.64 (3.27) mmHg x 10(3), P=0.025) and stiffness index (58.42 (47.76) vs 36.96 (33.43), P=0.033). The carotid (0.85 (0.35) vs 0.59 (0.23) mm, P<0.001) and femoral (1.05 (0.39) vs 0.69 (0.31) mm, P<0.001) IMTs are also significantly elevated in PVD patients. After adjustment for the presumed cardiovascular load assessed on the basis of a cumulative total vascular risk score, as well as age, systolic and diastolic pressure, the carotid viscoelastic indices and the carotid and femoral IMTs remained highly significant. However, the difference in femoral elastic variables was no longer evident. CONCLUSION: PVD per se affects the femoral and carotid wall mechanics and morphology similarly to other cardiovascular risk factors and events. These parameters may provide further information for cardiovascular risk assessment in addition to the classical risk factors and the Framingham equation. Indeed, some guidelines have suggested that additional factors such as the carotid scan may influence the clinician's decision to intervene with therapy.

Aged↗

The impact of trauma case management on patient outcomes.

BACKGROUND: Previous investigations demonstrate that nursing case management in the acute care setting improves patient outcomes. However, these findings provide limited information specific to trauma patients. METHOD: The effect of trauma case management (TCM) was measured using practice-specific variables such as in-hospital complications, missed injury rates, and length of stay. Other measures included staff satisfaction and use of allied health services. Data from 148 patients with an Injury Severity Score < 16 in the 5 months after the introduction of TCM were compared with 327 patients from the previous 12 months. RESULTS: Results demonstrated a trend toward reduced length of stay overall, more so in the older and more severely injured. TCM greatly improved missed injury detection rates (p < 0.0015) and coordinated allied health use more efficiently (p < 0.0001). Staff surveys exhibited a perceived dramatic improvement in the effectiveness of patient care (p < 0.0001). CONCLUSION: The introduction of TCM improved the efficiency and effectiveness of trauma patient care in our institution.

Adolescent↗

The roles of nitric oxide in dorsal root ganglion neurons.

The functions of nitric oxide (NO) in primary somatosensory neurons are reviewed. During the early development of these neurons the neuronal isoform of nitric oxide synthase (nNOS) is expressed during neurite extension. As their axons extend peripherally and start to take up nerve growth factor (NGF), nNOS starts to disappear from the majority of these neurons. A small number (less than 5%) continue to express nNOS, and for this small population NO may have a role in synaptic transmission. Following peripheral nerve section in adult rats, nNOS is reexpressed in many small peptidergic DRG neurons that have been axotomized. At the same time cGMP synthesis is increased in satellite glia cells. From culture studies, it was established that NGF negatively regulates nNOS synthesis in DRG neurons and that block of NO production leads to neuronal death. Further recent data is reviewed that supports the view that NO has a neuroprotective action preventing loss of DRG neurons and facilitates regeneration.

Animals↗

Does waiting for total hip replacement matter? Prospective cohort study.

OBJECTIVES: To assess the impact on the outcome of total hip replacement of the length of timing spent waiting for surgery. METHODS: One hundred and forty-three orthopaedic and general hospitals provided information about aspects of surgical practice for each total hip replacement conducted between September 1996 and October 1997 for publicly and privately funded operations in five English health regions. These data were linked to patient information about hip-related pain and disability status (measured using the Oxford Hip Score) before operation and at 3 and 12 months after. Data were analysed using multiple regression analysis. RESULTS: Questionnaires were completed by surgeons for 10,410 (78%) patients treated during the recruitment period and by 7151 (54%) patients. Twelve months after total hip replacement, the majority of patients experienced substantial improvements in hip-related pain and disability (as measured by the Oxford Hip Score). Those patients who started with a worse Oxford Hip Score before the operation tended to remain worse after the operation. Worse pre-operative score was associated with an increased length of either outpatient or inpatient wait, and this trend remained after the operation. The relationship between waiting time and outcome remained after adjustment for possible confounding variables. A consistently worse score was observed in public compared with private patients at all three time-points. In addition, in both sectors, those patients who were socially disadvantaged had a worse score than more socially advantaged patients both before and after the operation. CONCLUSIONS: Waiting for surgery is associated with worse outcomes 12 months later. Longer-term outcome needs to be considered to see if this association persists.

Activities of Daily Living↗

Frequency of the WHO metabolic syndrome in European cohorts, and an alternative definition of an insulin resistance syndrome.

BACKGROUND: To describe the frequency, in some European populations, of the World Health Organisation (WHO) defined metabolic syndrome and to compare the frequency of this syndrome with an alternative definition for non-diabetic subjects, called the insulin resistance syndrome proposed by the European Group for the Study of Insulin Resistance (EGIR). METHODS: Investigators of eight European studies contributed, according to a written protocol, the frequencies of abnormalities of these two syndromes, by sex and age class, as well as the overall frequencies of the syndromes and the average number of abnormalities: 8200 men and 9363 women were included. RESULTS: The frequency of both syndromes increased with age and was almost always higher in men than women for a given age. In non-diabetic subjects the frequency of the WHO syndrome varied between 7% and 36% for men 40 to 55 years; for women of the same age, between 5% and 22%. The EGIR syndrome was less frequent than the WHO syndrome (1% to 22% in men, 1% to 14% in women 40-55 years), and in men this was mainly due to the differing definitions of central obesity, as the WHO definition included overall obesity, BMI > or = 30 kg/m(2). CONCLUSIONS: There is great variability in the frequency of the syndrome between different populations, due to the differing frequencies of the abnormalities and no doubt to the differing methodologies of measurement. Prospective studies and advances in the knowledge of physio-pathological mechanisms are required to determine the most appropriate and practical definition of the syndrome.

Cohort Studies↗

INTERHEART.

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Adult↗