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Biomedical subjects

C A Rogers

Publications and source records attributed to C A Rogers.

At least 37 records · Page 2Linked to original sources
PubMed2000

Reducing stress responses in the pre-bypass phase of open heart surgery in infants and young children: a comparison of different fentanyl doses.

High-dose opioids are advocated for paediatric cardiac surgery to suppress stress responses but they can produce unwanted side effects. There are no data on the dose-dependent effects of opioids on the stress response on which to base rational opioid administration. We conducted a dose ranging study on 40 children less than 4 yr undergoing elective open heart surgery using one of five fentanyl doses: 2, 25, 50, 100 or 150 micrograms kg-1 before surgery. The standardized anaesthetic also included pancuronium and isoflurane. Blood samples were taken at induction, before incision, after sternotomy, immediately before, and at the end of cardiopulmonary bypass. Patients in the 2 micrograms kg-1 group had significant rises in prebypass glucose (P < 0.01), pre- and post-bypass cortisol (P < 0.01), and pre- and post-bypass norepinephrine (P < 0.01). No significant rise occurred in glucose, cortisol and catecholamines in any of the higher dosage groups. Patients in the 2 micrograms kg-1 group had significantly higher mean systolic blood pressure (P < 0.02) and heart rate (P < 0.04). A balanced anaesthetic containing fentanyl 25-50 micrograms kg-1 is sufficient to obtund haemodynamic and stress responses to the pre-bypass phase of surgery. Higher doses of fentanyl (100 and 150 micrograms kg-1) offer little advantage over 50 micrograms kg-1, and can necessitate intervention to prevent hypotension.

Anesthesia, General↗
PubMed2000

Nocturnal incontinence in women: a hidden problem.

PURPOSE: We determined the prevalence of nocturnal incontinence and its association with other storage symptoms in a community population of women MATERIALS AND METHODS: We mailed the validated self-reporting Bristol female lower urinary tract symptom questionnaire to all 2,641 women 19 years old or older registered at a family physician practice in a major British city and analyzed the results. Main outcome measures were the prevalence of nocturnal incontinence and its correlation with other storage symptoms. RESULTS: A total of 2,075 completed questionnaires (80%) were returned. The overall prevalence of nocturnal incontinence was 5.8%. However, the majority of women had nocturnal incontinence only occasionally and only 1% had it more than a third of the time. The prevalence of nocturnal incontinence increased in a linear fashion with age (chi-square test for linear trend p <0.005). Of the women with nocturnal incontinence 69% considered it troublesome. The odds of nocturnal incontinence were significantly increased when urge and stress incontinence, incontinence with no obvious cause, urgency, straining and nocturia were reported. CONCLUSIONS: Nocturnal incontinence in women is more common than generally supposed and troublesome. The rate of nocturnal incontinence increases with coexisting storage symptoms.

Adult↗
PubMed2000

Outdoor allergens.

Outdoor allergens are an important part of the exposures that lead to allergic disease. Understanding the role of outdoor allergens requires a knowledge of the nature of outdoor allergen-bearing particles, the distributions of their source, and the nature of the aerosols (particle types, sizes, dynamics of concentrations). Primary sources for outdoor allergens include vascular plants (pollen, fern spores, soy dust), and fungi (spores, hyphae). Nonvascular plants, algae, and arthropods contribute small numbers of allergen-bearing particles. Particles are released from sources into the air by wind, rain, mechanical disturbance, or active discharge mechanisms. Once airborne, they follow the physical laws that apply to all airborne particles. Although some outdoor allergens penetrate indoor spaces, exposure occurs mostly outdoors. Even short-term peak outdoor exposures can be important in eliciting acute symptoms. Monitoring of airborne biological particles is usually by particle impaction and microscopic examination. Centrally located monitoring stations give regional-scale measurements for aeroallergen levels. Evidence for the role of outdoor allergens in allergic rhinitis is strong and is rapidly increasing for a role in asthma. Pollen and fungal spore exposures have both been implicated in acute exacerbations of asthma, and sensitivity to some fungal spores predicts the existence of asthma. Synergism and/or antagonism probably occurs with other outdoor air particles and gases. Control involves avoidance of exposure (staying indoors, preventing entry of outdoor aerosols) as well as immunotherapy, which is effective for pollen but of limited effect for spores. Outdoor allergens have been the subject of only limited studies with respect to the epidemiology of asthma. Much remains to be studied with respect to prevalence patterns, exposure and disease relationships, and control.

Air Pollutants↗
PubMed1999

Elevated lead exposure in American woodcock (Scolopax minor) in Eastern Canada.

We investigated the degree and incidence of elevated lead (Pb) accumulation in the American woodcock (Scolopax minor) in eastern Canada by measuring the concentration of Pb in undamaged wing bones of 1,588 birds from Ontario, Quebec, Nova Scotia, and New Brunswick. Overall median bone-Pb concentrations were 21 microgram/g (DW) for adults and 11 microgram/g for young of the year. A high proportion of birds had elevated Pb concentrations, compared with other wild bird species. Fifty-two percent of adults and 29% of young of the year had bone concentrations exceeding 20 microgram/g. Pb concentration varied significantly with age, gender, and geographical region (p </= 0.0001). Mean Pb concentrations were lower for young of the year than for adults and lower for males than for females in both age groups. Atlantic Canada (New Brunswick and Nova Scotia) tended to have the highest frequency of individuals with elevated Pb accumulation. Potential sources of Pb exposure in woodcock include ingestion of spent lead shot from hunting, ingestion of Pb-contaminated soil, and/or ingestion of Pb-contaminated earthworms.

Aging↗
PubMed1999

A simple approach to risk stratification in adult heart transplantation.

OBJECTIVE: While there are numerous reports in the literature of risk factors for graft failure after heart transplantation, simple models for risk stratification are lacking. This study describes a simple method for risk stratification in adult heart transplantation that can be applied when the size of a dataset is insufficient for formal regression modelling. METHODS: Multi-centre prospective cohort study. Fourteen risk factors documented in the literature as increasing post transplant graft failure were used to formulate a model. Risk factors included in the model were recipient age >50 years, pre-operative ventilatory support, pre-operative circulatory support, >1 previous sternotomy, pulmonary vascular resistance >2.5 wood units, male with body surface area >2.5 m2, retransplant, ischaemic time >3.5 h, donor age >45 years, donor inotropic support >10 microg/kg per min dopamine, female donor, ratio donor/recipient body surface area <0.7, donor with diabetes and history of donor drug abuse. Four risk groups were defined depending on the number of risk factors present: Low, none; moderate, 1; high, 2 or 3; very high, 4 or more. Graft survival to 30 days was chosen as the primary outcome. The model was tested on 373 adult transplants performed in the UK between April 1995 and December 1996. RESULTS: Twenty eight transplants were low risk, 82 moderate, 201 high and 62 very high. The 30-day survival (70% CI) for the risk groups was low, 97% (93-100), moderate 95% (92-98), high 87% (84-89) and very high 80% (75-83) (P = 0.02). CONCLUSIONS: This preliminary model enables some stratification of heart transplant procedures according to donor and recipient risk profile. Further work will be directed at refining and validating the model.

Adult↗
PubMed1999

Variations in cardiac transplantation: comparisons between the United Kingdom and the United States.

BACKGROUND: International practice variations have been documented in various health care specialties. This study compares cardiac transplantation in the UK with practice in the US. METHODS: UK data were from an ongoing multi-center prospective study, the UK Cardiothoracic Transplant Audit. The UK population comprised 620 listings and 463 transplants. US data were obtained from UNOS and comprised 3946 listings and 4704 transplants. RESULTS: There was a mean of 14 transplants per center per year in the US compared with 34 in the UK. Notable differences in practice include rarity of listing in the UK of patients > 65 years (0.2% vs 4.1% in US) and patients with previous transplants (UK 0.9%, US 3.2%). Patients listed in the US were more likely to be on ventricular assist devices (odds ratio 8.0, 95% CI 3.0-21.7) or inotropes (odds ratio 4.9, 95% CI 3.7-6.4). Living donor (domino) transplants, although comprising 7% of transplants in the UK, are virtually non-existent in the US (1 domino in 4704 transplants). Heterotopic transplants were more common in the UK (4.4% vs 0.5%). Indications for transplant were similar (except retransplantation). The donor age was > 35 years in 43% of UK donors vs 33% of US donors. CONCLUSION: This study reveals substantial practice differences between the UK and US. Further studies are required to examine the reasons for these practice differences, the influence on transplant outcome, and their ethical and economic implications.

Adult↗
PubMed1999

Comparison of in-vitro pharmacodynamics of once and twice daily ciprofloxacin.

The pharmacodynamics of ciprofloxacin were explored in an in-vitro continuous bacterial culture model of infection, by simulating two oral dosing regimens; 0.5 g 12-hourly (bd) and 1 g 24-hourly (od). Three strains of Escherichia coli (ciprofloxacin MICs 0.03, 0.5 and 2 mg/L); two strains of Pseudomonas aeruginosa (MICs 0.09 and 1.5 mg/L), two strains of Staphylococcus aureus (MICs 0.12 and 1 mg/L) and two strains of Streptococcus pneumoniae (MICs 0.5 and 2 mg/L) were used. Three pharmacodynamic parameters, T > MIC, C(max)/MIC and AUC/MIC (T = time, C(max) = peak serum concentration, AUC = area under the curve), were compared with area under the bacterial-kill curve (AUBKC) (after transformation of the AUBKC) using a simple E(max) or sigmoidal E(max) model. AUBKC was taken to be the main antibacterial effect measure. The models were compared by inspection of residuals and Akaike information criterion. E(max) models adequately described the relationship between AUC/MIC and AUBKC and between C(max)/MIC and AUBKC, but not between T> MIC and AUBKC. All three pharmacodynamic parameters are related to each other but multiple regression analysis indicated that AUC/MIC was the best individual predictor of AUBKC. Despite this, comparison of od and bd regimens indicates some advantage to od in terms of early antibacterial effect. Serum concentration-time curve shape has some importance in determining antibacterial effect. These data indicate that for ciprofloxacin AUC/MIC ratio is not the sole determinant of antibacterial effect.

Anti-Infective Agents↗
PubMed1999

Urinary symptoms and incontinence in women: relationships between occurrence, age, and perceived impact.

BACKGROUND: The prevalence of urinary symptoms that impact on quality-of-life will be important in determining resource allocation in primary care groups. AIM: To determine the prevalence of urinary symptoms and their perceived impact in a community population of women. METHOD: A postal survey using a validated self-completed questionnaire among all women aged over 18 years and registered with one general practice in a major British city. The prevalence rates and perceived impact of a wide range of urinary symptoms and their relationship with age was determined. Data were analysed using the chi-squared test and the chi-squared test for trend. Spearman's rank correlation was used to assess the relationship between symptom severity and perceived impact. RESULTS: The number of completed questionnaires returned was 2075, giving an 80% response rate. Of these, the number of women who reported some degree of incontinence in the previous month was 1414 (69%), although only 578 (30%) indicated that it had social or hygienic impact. Other lower urinary tract symptoms reported included nocturia (19%), poor stream (19%), urgency (61%), and dysuria (23%). The most troublesome symptoms were incontinence for no obvious reason, nocturnal incontinence, and nocturia, with 73%, 69%, and 63% of sufferers, respectively, finding these symptoms troublesome. CONCLUSIONS: Incontinence and other urinary symptoms are more common than previously thought. These symptoms are not always perceived as bothersome or as having a social or hygienic impact, and therefore many women who report urinary leakage do not require treatment. Nocturnal symptoms in women are commoner than might have been supposed and are extremely troublesome to sufferers.

Adult↗
PubMed1997

Is subclinical ovarian failure an autoimmune disease?

Young women with unexplained infertility who exhibit elevated basal serum follicle stimulating hormone (FSH) concentrations (>10 IU/l) have poor outcomes in in-vitro fertilization. A subgroup of these women has regular menses, representing 'subclinical' ovarian failure, which may have an autoimmune basis and could potentially be treated by immunosuppression. To investigate this further, a range of immunological markers was used to assess autoimmune activity in 14 women aged <40 years with elevated FSH compared with 15 infertile women with normal FSH and 10 pre-menopausal, healthy controls. All samples were taken during natural menstrual cycles. Organ-specific antibodies against ovary, endometrium and thyroid, and non-organ-specific antibodies against histones and cardiolipin, were not significantly increased in elevated FSH patients compared with other control groups. Soluble CD23 and soluble intercellular adhesion molecule concentrations were not elevated in the sera of the women tested, and circulating T cell subsets remained unaltered. Significantly, increased concentrations of the complement breakdown product C3a and terminal complement complexes were detected in the elevated FSH group compared with the normal FSH group, although the latter also had significant complement activation compared with laboratory controls. Autoimmunity appears as an infrequent cause of 'subclinical' ovarian failure, but there is evidence of activation of complement in the sera of infertile women.

Adult↗
PubMed1997

Conclusions of the corneal transplant follow up study. Collaborating Surgeons.

AIM: On the basis of finalised data from the Corneal Transplant Follow up Study to identify and quantify factors influencing corneal graft outcome in terms of graft survival, rejection, visual acuity, and astigmatism. METHODS: Multifactorial analysis of 2777 grafts registered by the UK Transplant Support Service from July 1987 to June 1991. RESULTS: Several recipient factors influencing graft survival, rejection, and visual acuity were identified, but no donor factors. Of the operative factors amenable to change, mixed suturing was associated with reduced graft survival, and larger grafts with increased risk of rejection but better visual acuity when surviving. There was increased risk of rejection with poor matching at HLA class I antigens, but mismatched HLA-DR grafts suffered less rejection than those with zero HLA-DR mismatches. Recipient age below 10 years was associated with increased risk of both rejection and graft failure. However, whereas increasing age above 10 years was not associated with differential graft survival, it was significantly associated with decreasing risk of rejection. CONCLUSIONS: While confirming possible benefits of HLA-A and B matching, the expense and delay involved in awaiting matched HLA-DR tissue is unlikely to be justified. Other donor factors are unrelated to graft outcome following screening of tissue by eye banks. The highest rates of graft failure and rejection happen in the early postoperative period, and factors influencing visual outcome are also apparent at this stage.

Adolescent↗
PubMed1996

Cardiac transplantation in childhood cancer survivors in Great Britain.

The aim of this study was to identify patients treated in Great Britain for childhood cancer and subsequently referred for cardiopulmonary transplantation in order to assess diagnosis, cancer treatment, management and outcome. Computerised record linkage between the National Registry of Childhood Tumours and the national transplant database held and maintained by the United Kingdom Transplant Support Service Authority (UKTSSA) was used to identify patients. Verification and clinical details were then obtained from the oncology and transplant centres. 16 patients were identified from the 31992 cases of childhood malignancy diagnosed in Britain since 1970. These comprised 13 heart transplants, 2 heart/lung transplants and 1 patient who died while on the heart transplantation waiting list. All 14 potential heart transplant patients had cardiomyopathy presumed secondary to anthracycline therapy. The original diagnoses were acute myeloblastic leukaemia (3), Wilms' tumour (4), rhabdomyosarcoma (2) and one each of five different solid tumours. Median age at diagnosis was 44 months (range 4-165 months). Median anthracycline dose was 413 mg/m2 (range 240-680 mg/m2). 13 of the 14 potential cardiac transplantation patients were more than 2 years from end of their cancer treatment before requiring transplantation and the transplantation was performed 2-126 months after onset of cardiac failure at a median age of 163 months. Five year actuarial survival from transplantation was 74%. There was no recurrence of the original malignancy in any of these patients. Both heart/lung patients died, 3 and 11 months after the transplant. These heart transplantation data suggest that, in Britain, survival compares favourably with that of patients whose heart transplant was required for other causes of cardiomyopathy. This indicates that patients successfully treated for childhood cancer should not be excluded from transplant programmes.

Adolescent↗
PubMed1996

Effects of inhibition of complement activation using recombinant soluble complement receptor 1 on neutrophil CD11b/CD18 and L-selectin expression and release of interleukin-8 and elastase in simulated cardiopulmonary bypass.

The inflammatory response to cardiopulmonary bypass includes activation of complement and induction of several neutrophil activation pathways. A recombinant soluble form of complement receptor 1 was used as a specific inhibitor of complement activation in simulated cardiopulmonary bypass circuits. Substantial complement activation was observed in these circuits with progressive accumulation of both plasma C3a and terminal complement complex. Soluble complement receptor 1 resulted in a significant reduction in C3a levels (p < 0.01) but did not inhibit terminal complement complex generation. A marked rise in neutrophil CD11b/CD18 expression, simultaneous loss of L-selectin expression, and a progressive accumulation of plasma elastase-alpha 1-antitrypsin occurred and were not affected by soluble complement receptor. However, generation of interleukin-8 in the circuits was inhibited (p < 0.05) by pretreatment with soluble complement receptor. These data suggest that changes in neutrophil activation seen during cardiopulmonary bypass may not be induced directly by anaphylatoxin generation.

CD11 Antigens↗
PubMed1996

Clinical and surgical factors influencing corneal graft survival, visual acuity, and astigmatism. Corneal Transplant Follow-up Study Collaborators.

PURPOSE: To quantify clinical and operative factors that influence corneal graft outcome. METHODS: A multifactorial analysis was done on 2242 corneal grafts registered by the United Kingdom Transplant Service from July 1987 to June 1991. RESULTS: There was an increased risk of graft failure in patients with preoperative diffuse and other noncentral stromal edema, less-common eye diseases, small trephine size, difference in donor and recipient sizes greater than 0.25 mm, and use of mixed continuous and interrupted sutures. Visual acuity 3 months after surgery was poorer in patients who had glaucoma and low visual acuity preoperatively, small trephine size, and combined vitreous surgery. Use of interrupted sutures resulted in higher astigmatism at 3 months. CONCLUSIONS: After allowing for the effects of recipient factors, surgical factors significantly affected corneal graft outcome. No factors that showed significant benefits for graft survival also adversely affected visual performance. Details of medical history, clinical condition, and surgical method failed to predict more than a small proportion of observed variability in visual performance of functioning grafts.

Astigmatism↗
PubMed1996

Expression and function of membrane regulators of complement on rat astrocytes in culture.

Human astrocytes express CD59, decay accelerating factor and membrane cofactor protein to restrict the damaging effect of complement (C) activation on their cell surface. 5I2 antigen (5I2 Ag) is the functional analogue of the latter two proteins in rats. We here demonstrate the surface expression on rat astrocytes of CD59 and 5I2 Ag and use sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting to confirm their identity and to quantify expression. Rat CD59 (MW 20,000) was expressed at 720 x 10(3) molecules per cell and 5I2 Ag (MW 58,000 and 64,000) at 625 x 10(3) molecules per cell. Reverse transcription-polymerase chain reaction using specific oligonucleotide primers demonstrated expression of mRNA for each protein. Twenty-four-hour stimulation with inflammatory cytokines (interferon-gamma, tumour necrosis factor-alpha, interleukins-1 beta, -2 and -6) or phorbol myristate acetate had no significant effect on the level of expression of either protein as determined by Western blotting. Lysis caused by classical pathway activation of C in human or rat serum was enhanced by blocking the function of CD59 and 5I2 Ag on rat astrocytes with monoclonal antibodies.

Animals↗
PubMed1994

Influence of donor and histocompatibility factors on corneal graft outcome.

The Corneal Transplant Follow-up Study has followed 2311 penetrating keratoplasties for up to 450 days after transplant. A total of 207 failures were observed, including 65 classical rejections and 35 endothelial decompensations. At 12 months, graft survival was 89%, and survival free from rejection was 87%. For surviving grafts, risk of failure reduced from 4.8% in the first 75 days and stabilized after 5 months at 1.2% in each 75-day interval. Risk of rejection initially followed a similar pattern, but then increased after 12 months. Multifactorial analyses accounted for differences in recipient characteristics and interrelationships of donor factors. Donor age, sex, cause of death, and method of corneal storage were not found to influence significantly either time to graft failure or time to first rejection. Grafts in prospectively tissue-typed donor-recipient pairs were generally considered before surgery to be at increased risk of either graft failure or rejection. With due allowance, increasing risk of rejection was associated with increasing numbers of mismatches at HLA-A and HLA-B broad antigens. The opposite was true at HLA-DR broad antigens, where increased risk of rejection was observed with no mismatches.

Adult↗