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Biomedical subjects

P O'Grady

Publications and source records attributed to P O'Grady.

At least 19 recordsLinked to original sources

The influence of preclinical anaemia on outcome following total hip replacement.

INTRODUCTION: Preoperative anaemia confers a higher intraoperative and postoperative risk of complications on a patient. Preclinical anaemia is defined as a patient with laboratory indices of anaemia but without any of the symptoms. The patient population who undergo total hip replacement (THR) are elderly and are more likely to fall into this category. Our aim was to assess the effect of preclinical anaemia on a patient's postoperative course. MATERIALS AND METHODS: A prospective analysis of elective THRs performed over a 10-month period was carried out. Preoperative haematological indices were recorded and correlated with postoperative complication rates. RESULTS: A total of 225 elective THRs were included in the study. Patients with preclinical anaemia on admission had a higher incidence of postoperative infection and transfusion (p<0.001) and a longer postoperative inpatient stay. Preoperative iron supplementation in patients with preclinical iron deficiency anaemia resulted in a reduction in transfusion requirements (p=0.00125). CONCLUSIONS: Identification and treatment of patients with preclinical anaemia preoperatively may reduce postoperative infection and transfusion needs and result in a shorter inpatient stay.

Anemia↗

Hurling-related hand injuries.

Hurling is a contact sport, associated with significant morbidity. We have identified specific hand injuries sustained by participants and quantified the functional and financial implications of these injuries. Over a 3-month period, all hand injuries seen in the fracture clinic of our regional trauma unit were studied prospectively. Of the 123 consecutive injuries, 41 (33%) were sustained during hurling matches. Metacarpal (47%) and proximal phalangeal (37%) fractures were the most frequent. Eight hurlers (20%) required surgical intervention. Only four (10%) of the injured players were wearing hand protection. The mean cost of injury to the player was pound 615. We suggest the introduction of the mandatory use of hand protection for hurling.

Adolescent↗

The evolution of HOM-C homeoboxes in the Dipteran family Drosophilidae.

Forty-five new Homeotic Complex (HOM-C) homeobox sequences from six species of Drosophilidae (Drosophila heteroneura, D. adiastola, Zaprionus vittiger, Chymomyza amoena, Scaptodrosophila pattersoni and Hirtodrosophila pictiventris) were obtained using a PCR-cloning method. These new homeoboxes are from the labial, proboscipedia, Deformed, Sex combs reduced, fushi tarazu, Antennapedia, Ultrabithorax, abdominal-A and Abdominal-B genes. Phylogenetic signal in the homeobox sequences was assessed and several aspects of sequence evolution were examined. In particular, codon bias was examined and found to exist between the drosophilid species examined here and Anopheles gambiae outgroup sequences. In addition, different patterns of codon bias were detected in homeoboxes interrupted with introns when compared to homeoboxes that are uninterrupted.

Amino Acid Sequence↗

Shallow genomics, phylogenetics, and evolution in the family Drosophilidae.

The effects of the genomic revolution are beginning to be felt in all disciplines of the biological sciences. Evolutionary biology in general, and phylogenetic systematics in particular, are being revolutionized by these advances. The advent of rapid nucleotide sequencing techniques have provided phylogenetic biologists with the tools required to quickly and efficiently generate large amounts of character information. We use family Drosophilidae as a model system to study phylogenetics and genome evolution by combining high throughput sequencing methods from the field genomics and standard phylogenetic methodology. This paper presents preliminary results from this work. Separate data partitions, based on either gene function or linkage group, are compared to a combined analysis of all the data to assess support on phylogenetic trees.

Animals↗

Omapatrilat in patients with hepatic cirrhosis. Pharmacodynamics and pharmacokinetics.

OBJECTIVE: The pharmacodynamics and pharmacokinetics of omapatrilat, a member of a new class of cardiovascular compounds, the vasopeptidase inhibitors, were evaluated in subjects with hepatic cirrhosis (n = 10) and in healthy subjects (n = 10) matched for age, weight, gender and smoking history. METHODS: All subjects received omapatrilat 25 mg orally once daily for 14 days. Plasma renin and urinary atrial natriuretic peptide (ANP) levels were measured to assess the effect of omapatrilat on cirrhotic subjects. The effect of omapatrilat on blood pressure as well as changes in ANP and plasma renin levels were not altered by hepatic impairment. Pharmacokinetic parameters were determined from plasma omapatrilat concentrations. RESULTS: There were no significant differences between the two subject groups with regard to log-transformed area under the curve or maximum observed plasma concentration. Systemic accumulation was similar in the two groups. CONCLUSION: These results suggest, based on findings in otherwise healthy cirrhotic subjects, that no adjustment of standard dosing regimens is indicated for hypertensive patients with mild to moderate cirrhosis.

Administration, Oral↗

A critical appraisal of the out-patient fracture clinic: is communication really the key?

The most common factor in an adversarial doctor-patient relationship is failed communication. We audited our communication skills, patient satisfaction and assessed patients' capacity for retaining information. 120 consecutive first time patients with one of 5 fracture types were assessed. Patients scored (a) the doctor's communication skills and (b) their overall fracture clinic experience. Patient satisfaction was high, mean 8.2 (range 2-10, SD 1.76) points. There was a statistically significant difference in a patient's knowledge pre and post consultation. Forty-three patients (36%) could recall a specific consequence of the fracture (p<0.005). Forty (31%) and twenty six (22%) patients could recall the name of the Registrar and Consultant respectively. Doctors scored 9.2 (range 7-10, SD 1.23) points for communication skills. Patients are concerned with a fracture's impact on daily activities, often failing to register who treats them and any serious consequences. With doctors being scored so highly, the dilemma remains of how better to deliver the message.

Ambulatory Care↗

Comparison of the pharmacokinetics of fosinoprilat with enalaprilat and lisinopril in patients with congestive heart failure and chronic renal insufficiency.

AIMS: To compare the serum pharmacokinetics of fosinoprilat with enalaprilat and lisinopril after 1 and 10 days of dosing with fosinopril, enalapril and lisinopril. METHODS: Patients with congestive heart failure (CHF, NYHA Class II-IV) and chronic renal insufficiency (creatinine clearance </=30 ml min-1 ) were randomized to receive fosinopril, enalapril or lisinopril in two parallel-group studies. In the first study 24 patients were treated with 10 mg fosinopril (n=12 patients) or 2.5 mg enalapril (n=12) every morning for 10 consecutive days. In the second study 31 patients were treated with 10 mg fosinopril (n=16 patients) or 5 mg lisinopril (n=15) every morning for 10 consecutive days. Samples of blood were collected for determination of pharmacokinetic parameters. The area under the curve (AUC) between the first and last days of treatment and the accumulation index (AI) were the primary outcome measures. RESULTS: All three angiotensin converting enzyme (ACE) inhibitors exhibited a significant increase in AUC between the first and last days of treatment in both studies. The difference between the AI for fosinoprilat (1.41) and enalaprilat (1.96) was statistically significant (95% CI: 1.05, 1.84). Similarly, the difference between the AI for fosinoprilat (1.21) and lisinopril (2.76) was statistically significant (95% CI: 1.85, 2.69). All three ACE inhibitors completely inhibited serum ACE for 24 h. All treatments were well tolerated. CONCLUSIONS: Fosinoprilat exhibits significantly less accumulation than enalaprilat or lisinopril in patients with CHF and renal insufficiency, most probably because fosinoprilat is eliminated by both the kidney and liver, and increased hepatic elimination can compensate for reduced renal clearance in patients with kidney dysfunction.

Adolescent↗

Pharmacokinetics of single-dose oral stavudine in subjects with renal impairment and in subjects requiring hemodialysis.

Two open-label studies assessed the pharmacokinetics of single orally administered doses of 40 mg of stavudine in subjects with renal impairment. In one study (study I), 15 subjects with selected degrees of renal impairment, but not requiring hemodialysis, were stratified into three groups of five subjects each according to creatinine clearance (CL(CR)) normalized by body surface area (ml/min/1.73 m(2)): mild (CL(CR), 60 to 80), moderate (30 to 50), and severe (</=20) renal impairment. Five healthy subjects (CL(CR) >/= 90) were also enrolled. The stavudine area under the curve from 0 h to infinity (AUC(0-infinity)) increased nonlinearly with declining renal function: 1,864, 2,215, 3,609, and 5,928 ng. h/ml for normal renal function and for mild, moderate, and severe renal impairment, respectively (P = 0.0001 between renal impairment groups). The following stavudine dosage recommendations for renal impairment were proposed for subjects weighing >/=60 kg: CL(CR) of >50 ml/min/1.73 m(2), 40 mg every 12 h; CL(CR) of 21 to 50 ml/min/1. 73 m(2), 20 mg every 12 h; and CL(CR) of 10 to 20 ml/min/1.73 m(2), 20 mg every 24 h. For subjects weighing <60 kg, the proposed doses were 30, 15, and 15 mg, respectively, with the same dosing intervals specified above. In a second study (study II), 12 subjects with end-stage renal disease requiring hemodialysis three times a week were enrolled in a randomized, open-label crossover study (dialysis 2 h after dosing and lasting 4 h or dosing without dialysis). There were no statistically significant differences for AUC(0-infinity), AUC(2-6), time to maximum concentration of drug in serum, half-life, or apparent oral clearance when the two treatment dosage regimens were compared. As a result of study II, the recommended dosing rate for subjects requiring hemodialysis was the same as that proposed for those with severe renal impairment not requiring hemodialysis; however, dosing was recommended to follow hemodialysis and to occur at the same time each day.

Administration, Oral↗

An investigation into the role of oxygen free radical scavengers in preventing polymethylmethacrylate-induced necrosis in an osteoblast cell culture.

This study examined the effect of polymethylmethacrylate (PMMA) on osteocytic necrosis and the role of free radical scavengers in minimizing this damage. Bovine osteoblast cells with a characteristic phenotype were seeded at a density of 4x10(4) cells/cm2 and cultured in a DMEM supplemented with 10% fetal calf serum. A transwell insert with 2 cc of PMMA was suspended above the culture, and a time log response curve was established following elusion of free radicals around the osteoblast media. Chemiluminescence was used to determine quantitative free radical release. Using a Student's two-tailed t test there was a significant difference in the amount of hydroxyl radical released at 1-6 hours compared with controls (P=.028). Using histologic markers, there was a significant correlation between the use of PMMA and osteoblast cell necrosis. Transwell plates were coated with varying concentrations of mannitol, a known hydroxyl radical scavenger. A log dose response curve was established. There was a clear statistical association between a 10% mannitol solution and a reduction in the free radical release from PMMA (P=.03). Similarly, using Trypan blue histologic staining, there was a significant reduction in PMMA-induced cell necrosis when 10% mannitol was used as a scavenger (P=.01). A Rockwell superficial hardness test was used to determine whether mannitol had any effect on the surface hardness of the polymer. No statistical difference could be found between those treated with mannitol and controls at a depth of up to 1 mm. These results demonstrate hydroxyl radical is released from the polymerization reaction of PMMA. These radicals cause cell death in an osteoblast culture medium. This has been addressed using a 10% mannitol solution, which reduced cell necrosis.

Cells, Cultured↗

Fosinopril/hydrochlorothiazide: single dose and steady-state pharmacokinetics and pharmacodynamics.

AIMS: Fosinoprilat, the active product of fosinopril, is eliminated by an hepatic pathway in addition to the renal pathway shared by other angiotensin converting enzyme inhibitors (ACEIs). This study aimed to determine whether impaired renal function affects the pharmacokinetics and pharmacodynamics of a combination of fosinopril and hydrochlorothiazide (HCTZ). METHODS: The study had a parallel-group design comparing patients with renal impairment and body-mass-index-matched normal controls. The study was done in a University clinic in 13 patients with renal impairment (mean creatinine clearance 55.7+/-15.6 ml min-1 1.73 m-2 ) and 13 age-, sex-, and body-mass-index-matched normal controls (mean creatinine clearance 102.4+/-8.9 ml min-1 1.73 m-2 ). All patients and normal controls received fosinopril sodium 20 mg and HCTZ 12.5 mg as a daily oral administration on days 1-5. Non-compartmental pharmacokinetic parameters of fosinoprilat and HCTZ were determined from blood and urine samples obtained over 48 h starting on Day 1 (single dose) and Day 5 (steady state): maximum serum concentration (Cmax ), time to maximum serum concentration (tmax ), area under the serum concentration-time curve during the dosing interval (AUC), cumulative urinary excretion (CUE) and the accumulation index (AI; ratio of AUC-day 5/AUC-day 1). Pharmacodynamic parameters were also measured over 24 h on day 1 and over 48 h on day 5: serum ACE activity and arterial blood pressure. RESULTS: Fosinoprilat pharmacokinetic parameters on day 1 in renally impaired vs normal patients: Cmax=387+/-0.19 vs 324+/-0.25 ng ml-1 (P=0.07); tmax=3.5 vs 3.0 h (P=0.58); AUC=3510+/-0.29 vs 2701+/-0.35 ng ml-1 h (P=0. 072); CUE=5.08+/-2.70 vs 7.40+/-2.56% (P=0.009). Fosinoprilat parameters on day 5: Cmax=517+/-0.40 vs 357+/-0.19 ng ml-1 (P=0. 007); tmax=3.0 vs 3.0 h (P >0.99); AUC=4098+/-0.43 vs 2872+/-0.30 ng ml-1 h (P=0.027); CUE=6.81+/-3.53 vs 8.10+/-2.80% (P=0.068). AI=1. 17+/-0.33 vs 1.06+/-0.23 (P=0.29). In both groups ACE inhibition and blood pressure response were similar over 24 h and slightly greater 48 h after last dosing. CONCLUSIONS: In renally impaired subjects fosinopril and HCTZ can be coadministered without undue increases in fosinoprilat concentrations or any clinically significant pharmacodynamic effects. This is probably due to the dual excretory pathways for fosinoprilat.

Adolescent↗

The laminin-nidogen complex is a ligand for a specific splice isoform of the transmembrane protein tyrosine phosphatase LAR.

Leukocyte antigen-related protein (LAR) is a prototype for a family of transmembrane protein tyrosine phosphatases whose extracellular domain is composed of three Ig and several fibronectin type III (FnIII) domains. Complex alternative splicing of the LAR-FnIII domains 4-8 has been observed. The extracellular matrix laminin-nidogen complex was identified as a ligand for the LAR-FnIII domain 5 (Fn5) using a series of GST-LAR-FnIII domain fusion proteins and testing them in in vitro ligand-binding assays. LAR- laminin-nidogen binding was regulated by alternative splicing of a small exon within the LAR-Fn5 so that inclusion of this exon sequence resulted in disruption of the laminin-nidogen-binding activity. Long cellular processes were observed when HeLa cells were plated on laminin-nidogen, but not when plated on a fibronectin surface. Indirect immunofluorescent antibody staining revealed high expression of LAR in a punctate pattern, throughout the length of these cellular processes observed on laminin-nidogen. Antibody-induced cross-linking of LAR inhibited formation of these cellular processes, and inhibition was correlated with changes in cellular actin cytoskeletal structure. Thus, LAR-laminin-nidogen binding may play a role in regulating cell signaling induced by laminin-nidogen, resulting in cell morphological changes.

Alternative Splicing↗

Accumulation of lovastatin, but not pravastatin, in the blood of cyclosporine-treated kidney graft patients after multiple doses.

OBJECTIVES: To study pravastatin and lovastatin pharmacokinetic and pharmacodynamic effects and their interactions with cydosporine (INN, ciclosporin) in kidney transplant patients after single and multiple doses. SUBJECTS AND METHODS: The pharmacokinetic and pharmacodynamic effects of administration of 20 mg/day oral pravastatin and lovastatin for 28 days and their interactions with cyclosporine (2 to 6 mg/kg/day) were studied in a double-blind, double-dummy, randomized, parallel-group multicenter trial in 44 stable kidney graft recipients. RESULTS: The median area under the curve [AUC(0-24)] of pravastatin was 249 microg x hr/L (range, 104 to 1026 microg x hr/L) after a single dose (day 1) and 241 microg x hr/L (114 to 969 microg x hr/L) after multiple doses (day 28) and was fivefold higher than values reported in the absence of cyclosporine. The median AUC(0-24) of lovastatin was 243 microg x hr/L (105 to 858 microg x hr/L) on day 1 and 459 microg x hr/L (140 to 1508 microg x hr/L) on day 28. Besides a significant accumulation during the study period (p < 0.001), the lovastatin AUC(0-24) values were twentyfold higher than values reported without cyclosporine. Coadministration of pravastatin or lovastatin did not alter cyclosporine pharmacokinetics. In this study, 20 mg/day doses of both drugs resulted in a significant improvement of the lipid profile and were well tolerated. CONCLUSIONS: In contrast to lovastatin, pravastatin did not accumulate over the study period, which is probably one of the reasons rhabdomyolysis has been reported in lovastatin-treated but not pravastatin-treated transplant patients receiving cyclosporine immunosuppression.

Adult↗

Testing transposable elements as genetic drive mechanisms using Drosophila P element constructs as a model system.

The use of transposable elements (TEs) as genetic drive mechanisms was explored using Drosophila melanogaster as a model system. Alternative strategies, employing autonomous and nonautonomous P element constructs were compared for their efficiency in driving the ry+ allele into populations homozygous for a ry- allele at the genomic rosy locus. Transformed flies were introduced at 1%, 5%, and 10% starting frequencies to establish a series of populations that were monitored over the course of 40 generations, using both phenotypic and molecular assays. The transposon-borne ry+ marker allele spread rapidly in almost all populations when introduced at 5% and 10% seed frequencies, but 1% introductions frequently failed to become established. A similar initial rapid increase in frequency of the ry+ transposon occurred in several control populations lacking a source of transposase. Constructs carrying ry+ markers also increased to moderate frequencies in the absence of selection on the marker. The results of Southern and in situ hybridization studies indicated a strong inverse relationship between the degree of conservation of construct integrity and transposition frequency. These finding have relevance to possible future applications of transposons as genetic drive mechanisms.

Animals↗

Postgraduate training. Policy paper prepared by the Subcommittee on Postgraduate training: Permanent Working Group of European Junior Hospital Doctors.

The Permanent Working Group of European Junior Hospital Doctors (PWG) represents the interests, in international matters, of trainees from 23 member states. The PWG recognizes the importance of postgraduate training (PGT) in the maintenance of high quality health care delivery, and in this paper presents its current policy on PGT. This replaces its policy previously published in Medical Education 1989, 23, 339-47. The paper examines the context within which PGT occurs, and calls for an urgent review of its provision and funding. Basic principles, such as PGT existing within a continuum of medical education and the application of a quality assurance-based model, underpin the development of later sections on the structure, process and outcomes of PGT. These recommend the establishment of structured training programmes which should incorporate modern educational practice in the provision and monitoring of PGT. Emphasis is placed on the opportunities for training in the clinical setting and the utilization of a range of educational techniques. Evaluation and guidance by and of clinical supervisors and designated trainers is linked with the responsibilities of the trainee, and is placed within the context of a system of accountability, thus closing the quality assurance cycle. It is recommended that the views of the consumers of PGT, the trainees, are more fully considered in the development of training programmes. Finally, the potential for further harmonization is considered, with cautious advances being proposed.

Attitude↗

Flow cytometric analysis of kappa and lambda light chain expression in evaluation of specimens for B-cell neoplasia.

Analysis of light chain expression is one of the most important determinations in flow cytometric immunophenotyping of patient specimens. Numerous technical factors, such as antibody choice and cytophilic antibody artifact, impact a laboratory's ability to perform this test. There have been conflicting reports concerning the efficacy of polyclonal versus monoclonal antibodies, as well as methods of circumventing cytophilic antibodies, indicating that a consensus has not been reached on optimal methods for light chain determination. The authors have investigated methods for light chain analysis in 104 normal donors and 366 patient specimens, comparing different anti-light chain antibodies as well as strategies for analysis of specimens with low numbers of monoclonal B cells, admixed polyclonal B cells, or cytophilic antibodies. The patient specimens were either part of the initial diagnostic evaluation of patients with suspected lymphoma, or were performed for staging or assessment of treatment of patients with known B-cell neoplasia. No monoclonality was detected in control specimens, and there was no significant difference in staining with monoclonal verses polyclonal anti-light chain antibodies. In addition, cytophilic antibody did not obscure results in normal controls. Monoclonality was detected in 106 patient specimens, with 89 showing gross involvement with a predominant monoclonal B-cell process. However, in 43% of the grossly monoclonal specimens, there was failure to detect monoclonality with at least one light chain antibody set, with 8% of these cases showing failure with two anti-light chain sets. This indicates the importance of antibody choice in light chain analysis. Cytophilic antibody artifact in monoclonal specimens was easily overcome by appropriate antibody combinations, obviating the need for cytophilic antibody-shedding by incubation at 37 degrees C in fetal calf serum. In 27 patient specimens with low numbers of B cells or admixed polyclonal B cells, a clonal search based on FSC and CD19 or CD20 expression was performed. In 17 of the 27 cases (63%), a small monoclonal population was detected among admixed polyclonal B cells. The authors conclude that multiple strategies are necessary in flow cytometric analysis for B-cell monoclonality.

Antibodies, Monoclonal↗