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Biomedical subjects

Andrew Smith

Publications and source records attributed to Andrew Smith.

At least 109 records · Page 6Linked to original sources
PubMed2003

Caffeine and central noradrenaline: effects on mood, cognitive performance, eye movements and cardiovascular function.

There have been numerous studies on the effects of caffeine on behaviour and cardiovascular function. It is now important to clarify the mechanisms that underlie such effects, and the main objective of the present study was to investigate whether changes in central noradrenaline underlie some of the behavioural and cardiovascular effects of caffeine. This was examined using a clonidine challenge paradigm. Twenty-four healthy volunteers were assigned to one of four conditions: (i) clonidine/caffeine; (ii) clonidine/placebo; (iii) placebo/caffeine: (iv) placebo/placebo. Baseline measurements of mood, cognitive performance, saccadic eye movements and cardiovascular function were recorded. Subsequently, volunteers were given either clonidine (200 microg) or placebo and consumed coffee containing caffeine (1.5 mg/kg) or placebo. The test battery was then repeated 30 min, 150 min and 270 min later. A second cup of coffee (with the same amount of caffeine as the first) was consumed 120 min after the first cup. The results showed that clonidine reduced alertness, impaired many aspects of performance and slowed saccadic eye movements; caffeine removed many of these impairments. Both clonidine and caffeine influenced blood pressure (clonidine reduced it, caffeine raised it) but the effects appeared to be independent, suggesting that separate mechanisms were involved. In addition, there were some behavioural effects of caffeine that were independent of the clonidine effect (e.g. effects on speed of encoding of new information) and these may reflect other neurotransmitter systems (e.g cholinergic effects). Overall, the results suggest that caffeine counteracts reductions in the turnover of central noradrenaline. This mechanism may underlie the beneficial effects of caffeine seen in low alertness states.

Adolescent↗
PubMed2003

Ethics and ethnography: an experiential account.

In this article, the authors discuss an ethical dilemma faced by the first author during the fieldwork of an ethnographic study of expertise in anesthesia. The example, written from the perspective of the first author, addresses a number of ethical issues commonly faced, namely, the researcher-researched relationship, anonymity and confidentiality, privacy, and exploitation. She deliberates on the influences that guided her decision and in doing so highlights some of the elements that combine to shape the data. The authors argue that this process of shaping the data is a symbiotic one in which the researcher and the community being studied construct the data together.

Anecdotes as Topic↗
PubMed2003

CJD and the dentist.

The last 10 years have seen the emergence of a new disease termed variant CJD. This disease is thought to be initiated by abnormal prion proteins. This article reviews the different clinical manifestations of human prion diseases and provides some background information on the biological nature of this unique infectious agent. Prion proteins present a challenge to infection control because of their relative resistance to the conventional sterilization process. This article highlights the issues involved and discusses current guidelines for management of patients with human transmissible encephalopathies.

Creutzfeldt-Jakob Syndrome↗
PubMed2003

A contemporary validation of the Reeder Stress Inventory.

OBJECTIVES: To examine the construct validity of the RSI in a contemporary cohort. DESIGN: A cross-sectional investigation of 1,717 employed individuals who responded to the second stage of a study of occupational stress. METHODS: Scores on the RSI are compared to smoking and drinking habits, social class, and two measures of health (number of days sick leave, and number of visits to a GP during the previous year). The RSI was compared to three questionnaires measuring concepts related to stress: the 12-item General Health Questionnaire (GHQ-12), the Hospital Anxiety and Depression Scale (HADS), and the Karasek Job Strain Questionnaire. RESULTS: Higher levels of stress, as measured by the RSI, were associated with smoking a greater number of cigarettes, and, if the respondent drank alcohol, greater consumption of alcoholic drinks. High levels of stress were also associated with having taken more days sick leave, having made more frequent visits to a GP, and, somewhat unexpectedly, with being a teetotaller, and with holding a non-manual occupation. Of the questionnaire measures, the strongest association was between the RSI and HADS anxiety subscale, consistent with an overlap between the concepts of stress and anxiety. CONCLUSIONS: This study supports the construct validity of the RSI in a sample of employed individuals.

Adult↗
PubMed2003

Automated pneumococcal MLST using liquid-handling robotics and a capillary DNA sequencer.

Multilocus sequence typing (MLST) is used by the Scottish Meningococcus and Pneumococcus Reference Laboratory (SMPRL) as a routine method for the characterization of certain bacterial pathogens. The SMPRL recently started performing MLST on strains of Streptococcus pneumoniae, and here we describe a fully automated method for MLST using a 96-well-format liquid-handling robot and a 96-capillary automated DNA sequencer.

Automation↗
PubMed2003

CJD and the dentist.

Explore the source record for details and available documents.

Creutzfeldt-Jakob Syndrome↗
PubMed2002

Signaling through integrin LFA-1 leads to filamentous actin polymerization and remodeling, resulting in enhanced T cell adhesion.

The integrins can activate signaling pathways, but the final downstream outcome of these pathways is often unclear. This study analyzes the consequences of signaling events initiated by the interaction of the leukocyte integrin LFA-1 with its ligand, dimeric ICAM-1. We show that the active form of LFA-1 regulates its own function on primary human T cells by directing the remodeling of the F-actin cytoskeleton to strengthen T cell adhesion to ICAM-1. Confocal microscopy revealed that both F-actin bundling and overall levels of F-actin are increased in the ICAM-1-adhering T cells. This increase in F-actin levels and change in F-actin distribution was quantitated for large numbers of T cells using the technique of laser scanning cytometry and was found to be significant. The study went on to show that clustering of conformationally altered LFA-1 is essential for the changes in F-actin, and a model is proposed in which clustered, high-avidity T cell LFA-1, interacting with multivalent ICAM-1, causes LFA-1 signaling, which results in F-actin polymerization and higher-order F-actin bundling. The findings demonstrate that LFA-1 acts not only as an adhesion receptor but also as a signaling receptor by actively initiating the F-actin reorganization that is essential for many T cell-dependent processes.

Actin Cytoskeleton↗
PubMed2002

Meniscofemoral ligaments--structural and material properties.

The meniscofemoral ligaments (MFLs) of 28 human cadaveric knees were studied to determine their incidence, structural and material properties. Using the Race-Amis casting method for measurement, the mean cross-sectional area for the anterior MFL (aMFL) was 14.7 mm(2) (+/-14.8mm(2)) whilst that of the posterior MFL (pMFL) was 20.9 mm(2) (+/-11.6mm(2)). The ligaments were isolated and tensile tested in a materials testing machine. The mean loads to failure were 300.5 N (+/-155.0 N) for the aMFL and 302.5 N (+/-157.9 N) for the pMFL, with elastic moduli of 281 (+/-239 MPa) and 227 MPa (+/-128 MPa), respectively. These significant anatomical and material properties suggest a function for the MFL in the biomechanics of the knee, and should be borne in mind when considering hypotheses on MFL function. Such hypotheses include roles for the ligaments in knee stability and guiding meniscal motion.

Aged↗
PubMed2002

Coronary revascularization: a procedure in transition from on-pump to off-pump? The role of glucose-insulin-potassium revisited in a randomized, placebo-controlled study.

OBJECTIVE: To investigate an optimized glucose-insulin-potassium (GIK) solution regimen as an alternate myocardial protective strategy in off-pump coronary artery bypass graft (OP-CAB) surgery and as a supplement to conventional coronary artery bypass graft (CABG) surgery using cardiopulmonary bypass (CPB). DESIGN: Prospective, randomized, placebo-controlled. SETTING: Single institution, cardiothoracic specialty hospital. PARTICIPANTS: Forty-four patients scheduled for elective multivessel coronary artery surgery using either conventional CPB (n = 22) or OP-CAB techniques (n = 22). INTERVENTIONS: Preischemic, ischemic, and postischemic administration of GIK solution was carried out, optimally dosed to ensure nonesterified fatty acid (NEFA) suppression, and supplemented with magnesium, a glycolytic enzymatic cofactor. MEASUREMENTS AND MAIN RESULTS: GIK solution therapy reduced plasma NEFA levels (p < 0.001) in OP-CAB surgery and CPB groups but failed to affect the incidence of non-Q wave perioperative myocardial infarction, incidence of postoperative atrial fibrillation, incidence of postoperative infection, reduction in creatinine clearance, or duration of postoperative intensive care unit or hospital length of stay. After adjusting for GIK solution therapy, OP-CAB surgery resulted in significantly less ischemic injury (troponin I >15 microg/L, 19.0% v 91.3%; p = 0.0001) and reduced postoperative infections (14.3% v 43.5%; p = 0.049). CONCLUSION: GIK solution therapy achieved NEFA suppression and an insignificant trend toward reduced biochemical parameters of ischemic injury in OP-CAB surgery and CPB groups, but no major clinical benefit (perioperative myocardial infarction, intensive care unit length of stay, or hospital length of stay) was shown after elective CABG surgery in low-risk patients. Compared with CPB, OP-CAB surgery significantly reduced ischemic injury and postoperative infections.

Aged↗
PubMed2002

Effects of late loss of arterial inflow on free flap survival.

Greater than 80 percent of free flap thromboses have been shown to occur within the first three postoperative days, warranting immediate re-exploration and restoration of adequate vessel patency. The infrequency of thromboses beyond this period is reflected in the lack of reported cases in the literature and the absence of accepted guidelines for the treatment of such delayed complications. A single study reported free flap survival in vessel thromboses only when encountered after postoperative day (POD) 7 in a pig model. Since 1990, over 800 free tissue transfers have been done at the University of Rochester. A total of ten cases of late (defined as after POD 7) arterial inflow loss were identified and examined. A retrospective chart review recorded patient demographics, site of tissue defect, free tissue transferred, major co-morbidities, preoperative XRT, timing of arterial inflow loss, nature of inflow loss, and flap survival. The mean POD of arterial inflow loss was 53 days (range: 8 to 166). The mean age of patients was 58 years. No major co-morbidities correlated with late arterial inflow loss. Loss of inflow occurred as anastomotic rupture (5), occlusion of recipient bypass graft in lower extremity cases (3), primary donor arterial thrombosis (1), and pedicle avulsion during re-exploration for seroma (1). Five flaps survived, one sustained partial necrosis, and four were completely lost. Of the five surviving flaps, three were inset into healthy recipient sites. One was utilized on a dysvascular lower extremity, and another was used in an irradiated neck defect. Of the four failed flaps, all were placed in recipient beds compromised by radiation, ischemia, or scarring. Two exemplary case reports are presented. The timing of late loss of arterial inflow does not appear to be the primary determinant of free tissue survival. The condition and quality of the recipient site plays a large role in survival of these flaps. Ischemic, irradiated, and scarred beds are inadequate in providing late flap neovascularization, compared to healthy recipient sites. When encountering late loss of arterial inflow in flaps placed on such compromised beds, the microsurgeon should not anticipate survival based on surrounding vessel ingrowth. More aggressive salvage attempts may be warranted.

Adult↗
PubMed2002

The rate of increase in the numbers of primary sporadic basal cell carcinomas during follow up is associated with age at first presentation.

Basal cell carcinoma (BCC) patients demonstrate marked variation in tumour numbers and site. Previous studies also show an association between age at first BCC presentation and development of BCC on the trunk. In this study we have investigated the association between age at first presentation and the rate of development of truncal and non-truncal tumours in 747 patients with BCC. We used negative binomial regression analysis to show that increasing age at first presentation was associated with an increased rate of BCC development (rate ratio 1.01/year, 95% CI 1.01-1.02, P < 0.001). In particular, development of tumours was greater in cases aged 60.0-69.9, 70.0-79.9 and 80.0-89.9 years than in those 40.0-49.9 years (P = 0.05, 0.01 and 0.039, respectively). While few cases aged over 70 years of age first present with a truncal BCC, the numbers of BCC/year were greater than in those with a head/neck BCC. The data suggest different genetic factors mediate the appearance of BCC in patients of different ages particularly those aged above and below 60 years.

Adult↗
PubMed2002

What's new in ophthalmic anaesthesia?

PURPOSE OF REVIEW: There have been many changes in ophthalmic anaesthesia in the past few years. This review charts recent trends in practice. RECENT FINDINGS: Topical anaesthesia is gaining widespread use for ophthalmic surgery, but readers need to be aware that definitions vary widely; some 'topical' techniques also include intracameral injections and adjunctive sedation. There is now evidence on the relative effectiveness of different types of local anaesthesia from large systematic reviews. Furthermore, the notion is emerging that the traditional distinction between peribulbar and retrobulbar blocks may not be as clear-cut as previously thought. A new area of investigation is the effect of local blocks on pulsatile ocular blood flow. However, the risk of ocular ischaemia has yet to be quantified. Local anaesthesia has also been tried for posterior segment surgery with apparently successful results. The management of patients taking anticoagulants and anti-platelet agents has been examined, and it appears that there are risks not only in continuing therapy but also in stopping it peri-operatively. The decision thus has to be taken on the balance of risks. SUMMARY: There have been significant further gains in our understanding of local anaesthetic eye blocks and the management of patients undergoing such procedures.

Journal Article↗
PubMed2002

The combined use of pollen and soil analyses in a search and subsequent murder investigation.

This case report shows how soil analyses (particularly petrology) can be used in conjunction with pollen in order to refine or strengthen an association. Soil samples from a car believed to have been used by the suspect in a missing persons case was subjected to soil and pollen analyses. The soil characteristics and petrology were used to redefine the search area using geology and soils maps, the pollen and vegetative remains were used to target woodlands with a particular species mix. As a result two bodies were located and the environmental evidence was used in the subsequent trial. In this case the history of the vehicle was well known and the wheel arches and footwells provided reliable soil traps. The advantage of combining the techniques is that soil evidence (both mineralogy and other inclusions) provides a geological/soils match while the pollen provides independent evidence of vegetation type providing a combination that may be rare or unique.

Journal Article↗