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Biomedical subjects

M Flynn

Publications and source records attributed to M Flynn.

At least 19 recordsLinked to original sources
PubMed2005

Screen detected sclerosing lymphocytic lobulitis and amyloid of the breast in the same patient--a possible causal link.

Sclerosing lymphocytic lobulitis (SLL) and amyloidosis of the breast are both rare. We report the case of a 59 year old woman who presented with suspicious microcalcifications on routine screening mammography. Wire-guided excision biopsy showed features typical of SLL but also localised amyloid deposits within the specimen. Amyloidosis and SLL may have similar immunological causes. This patient represents the first documented association of these two disorders.

Amyloidosis↗
PubMed2004

Street canyon aerosol pollutant transport measurements.

Current understanding of dispersion in street canyons is largely derived from relatively simple dispersion models. Such models are increasingly used in planning and regulation capacities but are based upon a limited understanding of the transport of substances within a real canyon. In recent years, some efforts have been made to numerically model localised flow in idealised canyons (e.g., J. Appl. Meteorol. 38 (1999) 1576-89) and stepped canyons (Assimakopoulos V. Numerical modelling of dispersion of atmospheric pollution in and above urban canopies. PhD thesis, Imperial College, London, 2001) but field studies in real canyons are rare. To further such an understanding, a measurement campaign has been conducted in an asymmetric street canyon with busy one-way traffic in central Manchester in northern England. The eddy correlation method was used to determine fluxes of size-segregated accumulation mode aerosol. Measurements of aerosol at a static location were made concurrently with measurements on a platform lift giving vertical profiles. Size-segregated measurements of ultrafine and coarse particle concentrations were also made simultaneously at various heights. In addition, a small mobile system was used to make measurements of turbulence at various pavement locations within the canyon. From this data, various features of turbulent transport and dispersion in the canyon will be presented. The concentration and the ventilation fluxes of vehicle-related aerosol pollutants from the canyon will be related to controlling factors. The results will also be compared with citywide ventilation data from a separate measurement campaign conducted above the urban canopy.

Journal Article↗
PubMed2004

Fast-tracking revisited: routine cardiac surgical patients need minimal intensive care.

OBJECTIVE: Following cardiac surgery, patients are transferred from the operating theatre to intensive care. This clinical environment has one nurse per patient and facilities for mechanical ventilation. Patients are kept in this setting until the following day. This practice has been challenged with early extubation of patients. At our institution we have established a fast-track policy including the following features: (1) patient selection; (2) operating list scheduling with fast-track patients first; (3) anaesthetic tailored to early extubation; (4) methodical procedure with warm cardiopulmonary bypass; (5) removal of the arterial line; (6) transfer from intensive care to a separate high dependency unit ('step-down') on the day of operation, where the ratio of nurse to patient is one to three and there are no ventilatory facilities and no invasive monitoring; or (7) to keep these patients on ICU but decrease the nurse to patient ratio. METHOD: The case notes of 572 patients who predominantly had myocardial revascularisation, undergoing this process from July 1996 to July 2000 at our institution were reviewed. RESULTS: Mean EUROSCORE for the study group was 1.42. The 30-day mortality rate for the study group was 0.34%, mean intensive care time was 5 h 52 min, mean time to extubation was 3 h 10 min, mean readmission rate to intensive care was 0.34% and mean hospital stay from day of operation (inclusive) was 5.65 days. This process increased our throughput by 14.6% (compared to standard practices). COMMENT: This study demonstrates that transfer of appropriate patients to a high dependency area from intensive care following cardiac surgery is safe. It allows intensive care beds to be used by more than one patient each day and allows significant cost savings by reducing the nursing ratio per patient.

Adult↗
PubMed2003

Commentary: two seminal contributions of S. A. Roach to the evaluation and control of hazardous substances in air.

S. A. Roach was a pioneer in the assessment and control of hazardous substances in the working environment during the second half of the 20th century. The two papers discussed in this commentary are generally regarded as his most important scientific contributions. The first paper (Roach, 1977) dealt with the determinants of the body burdens of toxic air contaminants. Using simple kinetic models, he showed how levels of toxicants rise and fall in the body according to the patterns of airborne exposures received during relevant time windows. This led to several useful rules of thumb, including the timing of grab samples for 'fast acting' substances, the appropriate duration of air samples relative to the biological half time, how to deal with unusual work schedules, and how to integrate exposure assessment with control. He also offered sage advice regarding the meaning and interpretation of exposure limits, the importance of repeated monitoring, and the extent to which unacceptable levels of exposure might be reduced. In concluding this work, Roach emphasized that the hygienist can fulfill a central role in occupational health simply by intervening to reduce the body burden. The second paper (Roach, 1981) dealt with the design of effective ventilation systems to control worker exposure to toxic airborne contaminants. By developing a series of simple differential equations, Roach evaluated the impact of turbulent diffusion upon industrial ventilation. He emphasized that the stationary contaminant concentration was proportional to the contaminant generation rate and that velocity alone was not a sufficient design criterion to control exposures. Rather, he argued that the equivalent ventilation rate (the ratio of the contaminant generation rate to the steady concentration in the breathing zone) should be the guiding criterion for ventilation design. Throughout both papers, Roach used fundamental principles to tie together exposure assessment and engineering control, and pointed the way to a science for occupational hygiene. The profession can still learn a great deal from these seminal contributions.

Air Pollutants, Occupational↗
PubMed2001

Forced externalization of control in people with diabetes: a qualitative exploratory study.

AIM: The purpose of this study was to explore and describe the patients' perceptions of the Diabetic Disease State and its complications using an ethnographic method. BACKGROUND: Diabetes mellitus is an extensively researched and studied disease, however, relatively little attention has been given to the lived experience of chronic illness. METHODS: A purposive sample of 18 people with diabetes was derived from a diabetes register database. Data were collected by semistructured interviews, which were tape-recorded and transcribed. The transcripts were analysed together with the researchers' observational notes, using open coding procedures to identify main categories. Discussion of the results is made in the theoretical context of the locus of control (LOC) framework. FINDINGS: Three main categories emerged from the data: information-knowledge of illness; the psychological burden of diabetes; rationalizing. A further subcategory, reality avoidance, was identified. The findings showed that these people with diabetes experience and describe complex psychological effects and coping mechanisms in having a chronic illness. CONCLUSIONS: The findings also suggested that participants in this study might have felt that the control of their chronic condition had been externalized to the health care professionals responsible for their care.

Adaptation, Psychological↗
PubMed2001

The aortic Elan stentless aortic valve: excellent hemodynamics and ease of implantation.

The superior performance of stentless aortic valves with improved left ventricular hypertrophy regression and greater effective orifice area is proven. The Aortech Elan stentless valve (AESV) is a glutraldehyde preserved porcine valve with a pericardial reinforced inflow tract and a scalloped outflow to reduce bulk. We present the early results of AESV implantation at our institution. The first 41 consecutive recipients of the AESV at our unit, between November 1999 and December 2000, were studied. Mean preoperative New York Heart Association functional class (NYHA) status was 3.00 +/- 0.1. Patients requiring a bioprosthesis with suitable anatomy routinely received this implant. The AESV was implanted, either with an interrupted or continuous suture to the inflow tract and a continuous suture to the outflow tract. Transthoracic echocardiography was performed at 6 to 9 weeks after surgery, and aortic transvalvular gradients, flow velocities, and effective orifice areas (EOA) were calculated. In the early postoperative period, two patients with coronary artery disease died of low cardiac output. Echocardiography demonstrated competent valves. At follow-up, one patient was shown to have mild to moderate perivalvular leak with minimal symptoms. Two patients with aortic regurgitation secondary to bacterial endocarditis had no evidence of infection at 3 months after surgery. Mean transvalvular gradient was 6.91 +/- 0.87 mm Hg and mean effective orifice area was 1.18 +/- 0.04 cm(2)/m(2) at a mean of 8.4 weeks after surgery. AESV recipients for native aortic endocarditis were free from infection and regurgitation. The Elan stentless aortic valve demonstrates excellent early hemodynamic results, with very low transvalvular gradients, good flow characteristics and low regurgitation incidence. Ease of implantation is evidenced by favorable ischemic times. This valve may offer an option to homograft in acute aortic endocarditis. Long-term results are awaited.

Aged↗
PubMed2000

Remobilization of patients who fail to achieve minimal progenitor thresholds at the first attempt is clinically worthwhile.

A significant proportion of previously treated patients fail to mobilize sufficient stem/progenitor cells to enable high-dose therapy and peripheral blood stem cell transplantation to be performed. In this study, the value of remobilizing such patients has been evaluated in 20 patients who all failed to achieve progenitor yields of 1 x 10(6)/kg CD34+ cells and 1 x 10(5)/kg granulocyte-monocyte colony-forming units (GM-CFCs) at the first attempt. Most patients remained relatively poor mobilizers at the second mobilization, but the yield of CD34+ cells and GM-CFCs on the first apheresis was significantly greater with the second mobilization than the first. A total yield (all aphereses from both mobilizations) of > 1 x 10(6)/kg CD34+ cells and > 1 x 10(5)/kg GM-CFCs was achieved in 14 out of 20 patients. Seven patients have received high-dose therapy with stem cell infusion; neutrophil recovery was rapid in all patients and platelet independence occurred in < 21 d in five out of seven patients. We conclude that remobilization is worth considering in those patients in whom a chemotherapy-free interval of several months is possible.

Blood Component Removal↗
PubMed1999

Lipid reactivity to stress: II. Biological and behavioral influences.

This study examined behavioral and physiological influences on lipid concentrations during acute and chronic stressors. One hundred men (n = 92) and women (n = 8) were tested during a chronic stressor and during 2 acute stressors. During chronic stress, diet, physical activity, exercise, and sleep were examined. During the acute stressors, catecholamines, cortisol, plasma volume, and cardiovascular responses were examined. None of the behavioral influences could explain the lipid response to chronic stress. Responses of the atherogenic lipids to acute stressors were not solely reflecting hemoconcentration of the plasma but were moderately correlated with cardiovascular, epinephrine, and cortisol reactivity. Diastolic blood pressure reactors to the acute stressors had larger lipid responses to the chronic stressor than did nonreactors. Elevations in blood lipids during stress are not artifacts and may be clinically significant.

Acute Disease↗
PubMed1999

Frequency of convergence insufficiency among fifth and sixth graders. The Convergence Insufficiency and Reading Study (CIRS) group.

PURPOSE: To estimate the frequency of convergence insufficiency (CI) and its related clinical characteristics among 9- to 13-year-old children. METHODS: Fifth and sixth graders were screened in school settings at three different study sites. Eligible children with 20/30 or better visual acuity, minimal refractive error, no strabismus, and exophoria at near were evaluated according to a standardized protocol to determine the presence and severity of CI. These children were classified according to the presence and number of the following clinical signs: (1) exophoria at near > or =4delta than far, (2) insufficient fusional convergence, and (3) receded nearpoint of convergence. Also, children were classified as accommodative insufficient (AI) if they failed Hofstetter's minimum amplitude formula or had greater than a + 1.00 D lag on Monocular Estimate Method retinoscopy. RESULTS: Of 684 children screened, 468 (68%) were eligible for further evaluation. Of these, 453 had complete data on CI measurements and were classified as: no CI (nonexophoric at near or exophoric at near and < 4delta difference between near and far) (78.6%); low suspect CI (exophoric at near and one clinical sign: exophoria at near > or =4delta than far) (8.4%); high suspect CI (exophoric at near and two clinical signs) (8.8%); and definite CI (exophoric at near and three clinical signs) (4.2%). CI status varied according to ethnicity and study site (p < 0.0005), but not gender. The frequency of AI increased with the number of CI-related signs. For CI children with three signs, 78.9% were classified as also having AI. CONCLUSIONS: These findings suggest that CI (defined as high suspect and definite) is frequent (13%) among fifth and sixth grade children. In addition, there is a high percentage of CI children with an associated AI.

Accommodation, Ocular↗
PubMed1999

Neonatal and adult rabbit renal brush border membrane vesicle solute reflection coefficients.

The interaction between solute and water in epithelial transport is represented by the solute reflection coefficient. Because the osmotic water transport process changes in the rabbit proximal tubule during maturation, there is a potential for the solute reflection coefficients to also undergo maturational changes. In the present study, we directly examined solute reflection coefficients in neonatal and adult brush border membrane vesicles (BBMV) using the stop-flow light-scattering technique. Reflection coefficients for NaCl, KCl, NaHCO3 and urea were found to be identical in the neonatal and adult BBMV and were not different from 1. Thus, although the water transport pathway undergoes changes in the proximal tubule during maturation, there is no evidence for changes in solute and water interaction. Because the reflection coefficients are not different from 1, there is no evidence for solvent drag in the proximal tubule apical membrane in either the neonatal or adult tubule.

Aging↗
PubMed1999

Maturational changes in rabbit renal brush border membrane vesicle urea permeability.

Urea transport in the proximal tubule is thought to occur by passive diffusion through the lipid bilayers of the cell membranes. The lipid composition of cell membranes changes during maturation and may directly affect urea permeability of proximal tubule membranes. The present study examined the maturation of urea transport in rabbit renal brush border membrane vesicles (BBMV). BBMV from adult and neonatal (9- to 11-d-old) New Zealand white rabbits were loaded with 500 mM urea and mixed with an iso-osmotic mannitol solution using a stop-flow instrument. Vesicle shrinkage, due to efflux of urea, was followed with light scattering and urea permeability was calculated from an exponential fit of the data. Urea permeability was significantly lower in the neonatal BBMV than the adult at 25 degrees C (0.34+/-0.04 x 10(-6) versus 0.56+/-0.03 x 10(-6) cm/sec;p < 0.001, n=7) and 37 degrees C (0.45+/-0.04 x 10(-6) versus 0.66+/-0.03 x 10(-6) cm/sec; p=0.001, n=7). There was no effect of 250 microM phloretin on urea permeability in either adult or neonatal BBMV at either temperature. The activation energy for urea diffusion was higher in the neonatal than the adult BBMV. Because the maturational increase in urea permeability could potentially be due to a sodium-dependent urea transporter in the adult BBMV, the sodium dependence of urea uptake in adult BBMV was examined. There was no difference in urea permeability in the presence or absence of 20 mM NaCl. Permeability of the lipid-soluble molecule, glycerol, was also found to be the same in the neonatal and adult BBMV. Urea transport in the apical membrane of neonatal and adult proximal tubules is not phloretin sensitive, a finding consistent with diffusion of urea via the lipid bilayer. The rate of urea diffusion is lower in neonatal membranes and may be an important factor in overall urea excretion. This may also play a role in developing and maintaining a high medullary urea concentration and thus the ability to concentrate the urine during renal maturation.

Animals↗
PubMed1998

Laparotomy and laparoscopy differentially accelerate experimental flank tumour growth.

BACKGROUND: Surgery depresses host tumoricidal activity and may increase tumour growth. This study compared the effects of laparoscopy with laparotomy on extraperitoneal tumour growth and immune function in a murine model. METHODS: C57BL/6 female mice aged 8-10 weeks had tumours induced in the right flank (n=45) and were randomized to undergo halothane anaesthesia only, laparoscopy or laparotomy. Flank tumour volume was assessed over 10 days. A second group of animals (n=540) were randomized to undergo the same procedures and killed at 24, 48 and 96 h. Splenocytes were harvested for natural killer (NK) cell and lymphokine activated killer (LAK) cell cytotoxicity studies. RESULTS: There was a significant increase in flank tumour growth in the first 48 h after laparotomy and laparoscopy compared with controls (P < 0.01). By 96 h the difference was only significant in the laparotomy group (P< 0.01). Both NK and LAK cell cytotoxicities were suppressed significantly (P < or = 0.03) from 24 h up to 96 h following laparotomy compared with control and laparoscopy groups. There was also a significant suppression in the laparoscopy group compared with controls in the first 48 h after operation (P < or = 0.02). CONCLUSION: Extraperitoneal tumour growth was significantly accelerated after laparotomy and correlated with significantly suppressed NK and LAK cytotoxicity for at least 4 days after operation. Laparoscopy had a shorter, less profound effect on tumour growth and immune function.

Animals↗
PubMed1998

Risperidone for the treatment of behavioral disturbances in dementia: a case series.

The authors describe a series of 22 patients with dementia and behavioral disturbances, including agitation, aggression, delusions, and hallucinations, who were treated with risperidone. Risperidone, in low doses, was well tolerated; 50% of patients experienced significant improvement, although 50% experienced some extrapyramidal symptoms.

Aged↗