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Biomedical subjects

D L Patterson

Publications and source records attributed to D L Patterson.

At least 19 recordsLinked to original sources
PubMed2000

Anti-coagulant monitoring service delivery: a comparison of costs of hospital and community outreach clinics.

Anti-coagulated patients are monitored at regular intervals to ensure that their warfarin dosage is appropriate for their target International Normalized Ratio. The traditional setting for this monitoring has been the hospital clinic. Technological advances allow-- and with growing numbers of anti-coagulated patients, are leading to-- greater provision of monitoring clinics outside the hospital, at a more convenient location nearer patients' homes. This paper discusses the differences in organization between a hospital clinic and one set in the community (although provided by the hospital), and compares their costs. The comparison demonstrates the greater average cost per appointment in outreach of pound sterling 13.12 under current arrangements. Estimates are presented of incremental cost per appointment of pound sterling 3.93 and pound sterling 15.88 for a 10% increase in weekly patient numbers put through hospital and outreach clinics, respectively. Cost estimates are also presented for suggested alterations to hospital clinics that may reduce patient inconvenience, and the conditions under which outreach provision might be expanded at comparable cost to hospital provision are also examined.

Aged↗
PubMed1999

Prediction of the international normalized ratio and maintenance dose during the initiation of warfarin therapy.

AIMS: A pharmacokinetic/pharmacodynamic model, with Bayesian parameter estimation, was used to retrospectively predict the daily International Normalized Ratios (INRs) and the maintenance doses during the initiation of warfarin therapy in 74 inpatients. METHODS: INRs and maintenance doses predicted by the model were compared with the actual INRs and the eventual maintenance dose. Cases with drugs or medical conditions interacting with warfarin or receiving concurrent heparin therapy were not excluded. As the study was retrospective, model predictions of the maintenance dose were not those that were administered. Mean prediction error (MPE) and percentage absolute prediction errors (PAPE) were used to assess the model predictions. RESULTS: INR MPE ranged from -0.07 to 0.06 and median PAPE from 10% to 20%. Dose MPE ranged from -0.7 to 0.17 mg and median PAPE from 16.7% to 37.5%. Accurate and precise dose predictions were obtained after 3 or more INR feedback's. CONCLUSIONS: This study shows that the model can accurately predict daily INRs and the maintenance dose in this sample of cases. The model can be incorporated into computer decision-support systems for warfarin therapy and may lead to improvement in the initiation of warfarin therapy.

Adult↗
PubMed1998

Use of a light-addressable potentiometric sensor for the detection of Escherichia coli O157:H7.

We describe the development of an immunoligand assay (ILA) in conjunction with a light-addressable potentiometric sensor (LAPS) for the rapid detection of Escherichia coli O157:H7 cells in buffered saline. The ILA protocol consists of "sandwiching" bacterial analyte between biotinylated and fluoresceinated antibodies, indirect enzyme labeling of the bacteria with urease-labeled anti-fluorescein antibody, and active capture of the immune complex at a biotinylated bovine serum albumin-blocked nitrocellulose filter membrane with streptavidin. Using live E. coli O157:H7, the efficiency of the ILA was compared using various ratios of the biotinylated and fluoresceinated antibodies. Simultaneous addition of equimolar biotinylated and fluoresceinated antibodies effected optimal urease labeling and subsequent active capture of the bacteria in the ILA. Equimolar concentrations of the antibodies were varied to achieve optimal LAPS detection response for the live bacteria. Using ILA with LAPS, a minimum detectable level of ca. 7.1 x 10(2) cells/ml of heat-killed or ca. 2.5 x 10(4) cells/ml of live E. coli O157:H7 bacteria was achieved in Tris-buffered saline in an assay time of ca. 45 or ca. 30 min, respectively.

Biosensing Techniques↗
PubMed1997

Evaluation of a decision support system for initiation and control of oral anticoagulation in a randomised trial.

OBJECTIVE: To determine whether a computerised decision support system for initiation and control of oral anticoagulant treatment improves quality of anticoagulant control achieved by trainee doctors. DESIGN: Randomised controlled trial. SETTING: District general hospital in North London. SUBJECTS: 148 inpatients requiring start of warfarin treatment. INTERVENTIONS: Management by trainee doctors (to achieve therapeutic range of international normalised ratio of 2 to 3) with indirect assistance from computerised decision support system (intervention group) or without such assistance (control group). MAIN OUTCOME MEASURES: Median time to therapeutic range, stable dose, and first pseudoevent (excessive international normalised ratio after therapeutic range has been reached) and person time spent in the therapeutic range. RESULTS: 72 patients were randomised to the intervention group and 76 to control group. Median time to reach international normalised ratio of > or = 2 was not significantly different in the two groups (3 days). Median time to achieve a stable dose was significantly lower in intervention group than in controls (7 days v 9 days, P = 0.01) without excessive overtreatment or undertreatment with anticoagulant. Patients in intervention group spent greater proportion of time in therapeutic range, both as inpatients (59% v 52%) and outpatients (64% v 51%). CONCLUSION: The computerised decision support system was safe and effective and improved the quality of initiation and control of warfarin treatment by trainee doctors.

Administration, Oral↗
PubMed1997

Proinsulin-like molecules and plasminogen activator inhibitor type 1 (PAI-1) activity in diabetic and non-diabetic subjects with and without myocardial infarction.

Elevated plasminogen activator inhibitor type 1 (PAI-1) activity has been shown to correlate with plasma insulin, proinsulin-like molecules, serum triglycerides and insulin sensitivity in both non-insulin dependent diabetic (NIDDM) subjects and subjects with coronary heart disease. We examined the relative roles of these variables in determining PAI-1 activity in four groups of male caucasian subjects: non-diabetic subjects with (n = 38) and without (n = 38) previous myocardial infarction (MI) and NIDDM subjects with (n = 26) and without (n = 30) previous MI. Insulin and proinsulin-like molecules were measured using specific two-site immunometric assays and insulin sensitivity estimated using the Homeostasis Model Assessment (HOMA) model. Subjects were comparable in age and body mass index. In univariate analysis, there were significant correlations of PAI-1 activity with intact and des-31,32-proinsulin and serum triglycerides in non-diabetic subjects with (r = 0.52, P = 0.001; r = 0.58, P < 0.001; r = 0.41, P = 0.010) and without (r = 0.31, P = 0.056; r = 0.46, P = 0.006; r = 0.41, P = 0.011) MI, but not with plasma insulin or insulin sensitivity. In NIDDM subjects, PAI-1 activity correlated significantly with intact and des-31,32-proinsulin and serum triglyceride (r = 0.47, P = 0.015; r = 0.58, P = 0.002; r = 0.44, P = 0.026) only in subjects with MI. In multiple regression analysis, MI was the most important determinant of PAI-1 activity levels (r2 = 0.31, F = 55.6, P < 0.001). In conclusion, concentrations of proinsulin-like molecules and serum triglycerides appear to be stronger determinants of PAI-1 activity than plasma insulin or insulin sensitivity in both NIDDM subjects and non-diabetic subjects with and without MI. However, the relationship of MI with PAI-1 activity is independent of these variables.

Diabetes Mellitus, Type 2↗
PubMed1997

Adolescent mothering: child-grandmother attachment.

This study explored the involvement of maternal grandmothers with children of adolescent mothers and child-grandmother attachment. In a sample of 32 children whose grandmothers were involved in child care, 44% were securely attached to mothers and 72% securely attached to grandmothers. Of the 18 children insecurely attached to mothers, 82.4% were securely attached to grandmothers. A significant relationship existed between attachment security and the time the child was with grandmother, sleeping time excluded. In contrast, time with mother was not related. Based on attachment theory, findings are presented and implications for nursing practice are made.

Adolescent↗
PubMed1997

Comparison of oral anticoagulant control by a nurse-practitioner using a computer decision-support system with that by clinicians.

With increasing work-loads in anticoagulant clinics different methods of service delivery need evaluation. The quality of anticoagulant control achieved by a nurse-practitioner using a computer decision-support system (CDSS) was compared with that achieved by trainee doctors without CDSS. Eighty-one out-patients (group A, therapeutic range 2-3) and 96 out-patients (group B, therapeutic range 3-4.5) were randomized to management by a nurse-practitioner or by trainee doctors (clinicians). Thirty-seven patients in group A and 50 patients in group B were randomized to be managed by the nurse-practitioner. In group A, patients in the nurse-practitioner group spent a longer time in the therapeutic range than those in the clinician group (60.7% compared with 51.6%). Dose suggestion acceptance in the nurse-practitioner group (88%) was higher compared with agreement between the CDSS and the clinicians (60%). In group B, patients in the clinician group spent a slightly longer time in the therapeutic range (70% compared with 67.6%). Acceptance of dose suggestion was lower in the nurse-practitioner group (67%) compared with agreement between the CDSS and the clinicians (73%). In conclusion, the CDSS can improve the quality of control of warfarin therapy by a nurse-practitioner over that by trainee doctors for the therapeutic range 2-3. Similar quality of control is achieved for the therapeutic range 3-4.5. The CDSS may be used by nurse-practitioners to achieve safe and effective anticoagulation in hospital-based or out-reach anticoagulant clinics.

Administration, Oral↗
PubMed1995

Displaying the long-term progression of patients with coronary artery disease.

Cardiac clinicians are often faced with the problem of trying to assimilate details of a patient's long-term history. Case notes are often lengthy, making this process difficult if not impossible in the time available during an outpatient examination. A computer system has been developed to assist with this task. This generates a graphical summary of the principal features of a patient's long-term progression. It gives an overview of how the patient's anginal status has changed, his or her drug treatment and any surgical interventions. The system also allows the clinican to display summaries of diagnostic tests carried out. The system can be used to assist clinical management and speed up outpatient examination. It can also be used to facilitate case conference sessions and has potential for being used in medical education.

Coronary Disease↗
PubMed1995

Anaphylaxis induced by the carboxymethylcellulose component of injectable triamcinolone acetonide suspension (Kenalog).

BACKGROUND: Allergic reactions to various corticosteroids are rare but have been reported previously. OBJECTIVE: We wished to determine the etiology of an anaphylactic reaction in a patient who had received intracutaneous Kenalog (triamcinolone acetonide). METHODS: Skin testing and serologic testing for allergen-specific IgE antibodies was performed for triamcinolone acetonide, its individual components, and three other corticosteroid preparations in both the patient and six other nonallergic persons. RESULTS: The patient had positive skin tests to only the carboxymethylcellulose component of triamcinolone acetonide. He had negative skin test reactions to three other steroid preparations which did not contain carboxymethylcellulose. Specific IgE antibodies to carboxymethylcellulose were also elevated by immunoassay and immunoblotting. Control patients had negative skin tests to triamcinolone acetonide, its components, and three other corticosteroid preparations, and their sera lacked significant specific IgE antibodies to these materials. CONCLUSIONS: Our results indicate that the triamcinolone acetonide component responsible for the patient's reaction was the suspending agent carboxymethylcellulose. We urge physicians to consider component testing when patients experience allergic-type reactions to drugs.

Adult↗
PubMed1995

Determinants of plasminogen activator inhibitor-1 activity in survivors of myocardial infarction.

A significant relationship has been described between plasminogen activator inhibitor-1 (PAI-1) and plasma insulin concentrations. However, most radioimmunoassays (RIA) substantially overestimate plasma insulin concentrations because of cross reaction with proinsulin-like molecules and it has been proposed that proinsulin-like molecules may be important determinants of PAI-1 activity. We measured fasting plasma immunoreactive insulin by conventional RIA, fasting plasma insulin (EIMA) by specific two site immunoenzymometric assay, and intact proinsulin and des-31,32-proinsulin by two site immunoradiometric assay (IRMA) in 74 (50 nondiabetic and 24 diabetic) subjects who had survived a myocardial infarction between 6 and 24 months previously. In univariate analysis, PAI-1 activity correlated with serum triglycerides (rs = 0.43; p < 0.0001), insulin sensitivity (rs = -0.30; p = 0.004), and immunoreactive insulin (rs = 0.45; p < 0.0001). However, the relationship between PAI-1 activity and plasma specific insulin (IEMA) was weaker (rs = 0.24; p = 0.019) than those with intact proinsulin (rs = 0.53; p < 0.0001) and des-31,32-proinsulin (rs = 0.54; p < 0.0001) despite the low concentrations of these proinsulin-like molecules. In multiple regression analysis, only des-31,32-proinsulin (p = 0.001) and serum triglycerides (p = 0.013) were significant determinants of PAI-1 activity. In conclusion, these results suggest that proinsulin-like molecules and serum triglycerides are important determinants of PAI-1 activity in survivors of myocardial infarction.

Aged↗
PubMed1995

Personal aerosol protection devices: caring for victims of exposure.

The increased incidence of violence in our society has led to a concern for personal safety. For self-protection, many individuals are turning to personal aerosol protection devices (PAPDs), which are readily accessible to the general public. The greater use and misuse of these noxious chemicals has led to an increase in injuries associated with exposure. Health care providers need to be aware of the modes of action of PAPDs, the presenting exposure symptoms, first aid measures, and decontamination procedures of the environment and the victim's belongings. This article provides a thorough discussion of PAPDs and will assist the clinician in delivering primary care and health education to victims of PAPD exposures.

Aerosols↗
PubMed1995

Validation of an algorithm for oral anticoagulant dosing and appointment scheduling.

Computer clinical decision-support systems require validation before clinical use. This study compared recommendations on warfarin dosage adjustment and timing of the next appointment made by an algorithm with those made by experienced and inexperienced clinicians. Data abstracted from the records of 125 patients seen regularly in the anticoagulant clinic were used. The algorithm recommended dose changes and next appointment for cases with INRs between 1.8 to 4.2 (therapeutic range 2.0-3.0) and between 2.3 to 5.3 (therapeutic range 3.0-4.5). Beyond these values the algorithm referred the cases to "see doctor'. Compared to experienced clinicians, the algorithm was better at "recognising' difficult patients than inexperienced clinicians (kappa = 0.43 and 0.32 respectively). There was no statistically significant difference between all decision makers in dosage recommendations for the non-difficult cases, but there was much more variation amongst the inexperienced clinicians. The interval recommendations were statistically different between and within the different decision-makers. The inexperienced clinicians tended to give relatively longer intervals for a given dose change. In conclusion, the algorithm performs better than inexperienced clinicians and as well as experienced clinicians for the non-difficult cases.

Algorithms↗
PubMed1994

Severe asthma complicated by bilateral diaphragmatic paralysis attributed to Parsonage-Turner syndrome.

Progressive dyspnea that developed in a 52-year-old woman with a lifelong history of asthma did not respond to high-dose orally administered glucocorticoids. Initially, a diagnosis of allergic bronchopulmonary aspergillosis or hypersensitivity pneumonia was suggested as the cause of the worsening dyspnea. Pulmonary function tests demonstrated severe airway obstruction; substantial improvement was noted after bronchodilator therapy. Maximal inspiratory pressure was decreased, and the diffusing capacity of the lungs was abnormal. Computed tomography of the chest showed no parenchymal or mediastinal abnormalities. During a sniff test, fluoroscopy of her diaphragm disclosed paradoxical motion of both hemidiaphragms during inspiration, consistent with bilateral hemidiaphragmatic paralysis. Parsonage-Turner syndrome was diagnosed. The dose of glucocorticoids was tapered. Follow-up of the patient by telephone contact in March 1994 (9 months after her initial examination at our clinic) revealed that the dyspnea was still severe.

Asthma↗
PubMed1993

"Spontaneous" platelet aggregation in whole blood in diabetic and non diabetic survivors of acute myocardial infarction.

There is increasing evidence that platelet thrombi play an important role in the pathogenesis of acute myocardial infarction (AMI). We compared "spontaneous" platelet aggregation in whole blood in 17 non-diabetic and 12 diabetic subjects on admission with AMI. There was no significant difference in the fall in platelet count between the two groups, expressed as platelets remaining (75.2 +/- 7.9% vs 77.3 +/- 6.9% at 10 min, 66.6 +/- 8.9% vs 68.5 +/- 6.3% at 20 min, 63.5 +/- 8.2% vs 64.9 +/- 6.7% at 30 min and 59.4 +/- 10.3% vs 61.3 +/- 7.6% at 60 min). The rate of "spontaneous" aggregation was increased in subjects with evidence of heart failure on admission compared to those without (59.9 +/- 7.9% vs 66.2 +/- 6.6% at 30 min [p = 0.05] and 55.4 +/- 9.6% vs 63.1 +/- 7.7% at 60 min [p = 0.04]). There was no correlation between the fall in platelet count and admission plasma glucose, glycated haemoglobin or peak aspartate amino-transferase. The subjects studied on admission with AMI had greater rates of "spontaneous" aggregation than 8 subjects studied between 6 and 12 months after acute myocardial infarction (75.9 +/- 7.4% vs 85.8 +/- 5.4% at 10 min; p = 0.001 and 64.3 +/- 7.5% vs 75.0 +/- 7.8% at 30 min; p = 0.006) and compared to normal controls (90.7 +/- 4.4% at 10 min; p < 0.001 and 83.4 +/- 6.5 at 30 min; p < 0.001). This study provides evidence of increased "spontaneous" platelet aggregation in subjects admitted with acute myocardial infarction but no difference between diabetic and non-diabetic subjects was observed.

Aged↗