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Biomedical subjects

D L Patterson

Publications and source records attributed to D L Patterson.

At least 37 records · Page 2Linked to original sources
PubMed1993

Traumatic rupture of an aortic ulcerative atherosclerotic plaque producing aortic dissection: a complication of interscapular back blows used to dislodge objects from the esophagus.

Penetrating atherosclerotic ulcer of the aorta is a rare entity which usually occurs in the descending thoracic aorta. Herein, we report an unusual case of penetrating aortic ulcer which ruptured into the mediastinum. Interscapular back blows were performed on our patient in an attempt to dislodge an aspirin which she thought was lodged in her esophagus. Unlike previously reported cases of this entity, the penetrating aortic ulcer in our patient was located in the distal thoracic ascending aorta. Diagnosis of penetrating aortic ulcer can be made by utilizing aortography, contiguous dynamic contrast-enhanced computed tomography or magnetic resonance imaging. Treatment consists of adjunctive medical therapy until surgery can be performed.

Aged↗
PubMed1993

Free-radical activity after reperfusion in diabetic and non-diabetic patients with acute myocardial infarction.

1. Oxygen-derived free radicals have been implicated in reperfusion injury after thrombolytic therapy in acute myocardial infarction. To test the hypothesis that diabetic patients may have increased oxidative stress which may lead to increased reperfusion damage and thereby contribute to a poorer outcome in these patients, we measured two indices of free-radical activity, diene conjugate molar ratios as an index of lipid isomerization and thiobarbituric acid-reactive material as an index of lipid peroxidation, in 66 non-diabetic and 26 diabetic patients admitted with acute myocardial infarction who received thrombolytic therapy and in whom reperfusion was assessed using early time to peak creatine kinase-MB isoenzyme release. 2. Baseline diene conjugate molar ratios or thiobarbituric acid-reactivity did not differ significantly between diabetic and non-diabetic patients (1.97 +/- 0.98 versus 2.16 +/- 1.34; not significant and 2.10 +/- 0.60 versus 1.99 +/- 0.73 mumol/l; not significant). In patients with enzymic evidence of reperfusion (i.e. time to peak enzyme release < or = 12 h) diene conjugate molar ratios peaked at 6 h compared with 12h in those with unsuccessful reperfusion (i.e. time to peak enzyme release > 12 h). In patients with unstable angina the maximum increase in the diene conjugate molar ratios was significantly less than in patients with acute myocardial infarction (6.80 +/- 12.3 versus 15.82 +/- 22.55%; P = 0.035). There was a significant fall in thiobarbituric acid-reactivity at 24 h in patients with enzymic evidence of reperfusion (P = 0.017). There were no major differences in these rises and falls between diabetic and non-diabetic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina, Unstable↗
PubMed1993

Relationship between functional status and health-related quality-of-life after myocardial infarction.

Despite increasing use in clinical and economic studies, no gold standard exists for the measurement of health-related quality of life (HRQL). One approach to assessing the validity of an HRQL instrument for a particular disease population is to examine the empirical relationship between HRQL patient scores and other accepted measures of health or functional status. In 185 patients (mean age 60 years, 79% male) at six months after myocardial infarction, we examined the relationship between patient responses to the Nottingham Health Profile (NHP), a generic HRQL instrument, and physician classification of patients by two widely used functional status indicators: the New York Heart Association (NYHA) classification and the Karnofsky Performance Status Scale. Analysis of NHP scores by NYHA strata confirms that lower HRQL is associated with poorer cardiac functional status (P < 0.0001) and this gradient is observed over all six NHP domains. Statistically significant (P < 0.001) associations were observed between patients' NYHA class and NHP domain scores for energy (Spearman r = 0.52), physical mobility (r = 0.45) and pain (r = 0.43). NHP scores for patients in NYHA Class I were similar to male population controls. A similarly consistent relationship was found between NHP and Karnofsky. We conclude that the NHP is able to discriminate between patients with differing levels of cardiac functioning as classified by NYHA and patient functioning as classified by Karnofsky. Demonstration of such discriminative properties is one important component in assessing the construct validity of HRQL measures.

Activities of Daily Living↗
PubMed1993

Plasminogen activator inhibitor: a risk factor for myocardial infarction in diabetic patients.

OBJECTIVE: To determine whether diabetic patients admitted with acute myocardial infarction have impaired fibrinolytic activity due to raised plasminogen activator inhibitor compared with non-diabetic patients. SETTING: A district general hospital. PATIENTS: 90 non-diabetic and 38 diabetic patients admitted with acute myocardial infarction. RESULTS: Both plasminogen activator inhibitor activity and antigen were significantly higher in diabetic than in non-diabetic patients (24.7 (6.8) v 18.5 (6.8) AU/ml; p = 0.0001 and 64.2 (range 13.1 to 328.8) v 38.5 (range 10.9 to 173.7 ng/ml; z = 3.3; p = 0.0008) with a positive correlation between activity and antigen (rs = 0.51; p = 0.0001). In both groups, activity and antigen concentrations were significantly higher than in diabetic and non-diabetic subjects without coronary artery disease (p = 0.002 to 0.0001 for each comparison). Plasminogen activator inhibitor activity correlated significantly with admission plasma glucose (r = 0.32; p = 0.0001), glycated haemoglobin (r = 0.32; p = 0.0001), admission plasma insulin (rs = 0.48; p = 0.001), and Killip grade of heart failure both on admission (rs = 0.27; p = 0.001) and on discharge (rs = 0.22; p = 0.006), but not with cumulative creatine kinase MB isoenzyme release (rs = -0.08). There were similar but weaker correlations between tissue plasminogen activator antigen and admission plasma glucose, glycated haemoglobin, and insulin. In 18 patients (12 non-diabetic and six diabetic) plasminogen activator inhibitor activity was measured between six and 12 months (8.3 (1.6)) after the acute infarct and remained similar to activity on admission (24.8 (1.9) AU/ml (NS) for diabetic and 17.9 (6.9) AU/ml (NS) for non-diabetic patients) and was still significantly higher in diabetic than in non-diabetic patients (p = 0.007). CONCLUSION: These results show that diabetic patients have higher plasminogen activator inhibitor activity than non-diabetic patients both on admission with acute myocardial infarction and at follow up six to 12 months later. Raised plasminogen activator inhibitor activity may predispose diabetic patients to myocardial infarction and may also impair pharmacological and spontaneous reperfusion after acute myocardial infarction thus contributing to the poor outcome in these subjects.

Aged↗
PubMed1993

Enzymatic evidence of impaired reperfusion in diabetic patients after thrombolytic therapy for acute myocardial infarction: a role for plasminogen activator inhibitor?

OBJECTIVE: To compare the activity of plasminogen activator inhibitor (PAI-1) in diabetic and non-diabetic patients admitted with acute myocardial infarction and to determine whether PAI-1 activity influences reperfusion after thrombolytic therapy. DESIGN: Prospective study of patients admitted with acute myocardial infarction. SETTING: District general hospital. MAIN OUTCOME MEASURES: Reperfusion assessed by time to peak release of creatine kinase-MB isoenzyme. RESULTS: Baseline PAI-1 activity and antigen concentrations were significantly higher in diabetic patients (n = 45) than in non-diabetic patients (n = 110) (24.6 (6.9) v 18.6 (7.9) AU/ml (AU = arbitrary units) (p = 0.0001) and 58.8 (13.1-328.8) v 41.0 (10.9-125.4) ng/ml (p = 0.004). Time to peak release of creatine kinase-MB was calculated in 123 (80%) patients. In 98 who received thrombolytic therapy the median time to peak enzyme release was 15.5 h (7.5-24 h) in diabetic patients (n = 26) and 12 h (5-26 h) in non-diabetic patients (n = 72) (p = 0.005). In those with a time to peak release of < or = 12 h, indicating likely successful reperfusion, PAI-1 activity was 17.5 (7.8) AU/ml compared with 22.8 (7.7) AU/ml in those with a time to peak release of > 12 h (p = 0.001). In multiple regression analysis both diabetes (p = 0.0001) and PAI-1 activity at admission (p = 0.029) were independently related to successful reperfusion. In 13 patients with evidence of reinfarction in hospital PAI-1 activity on day 3 was 26.7 (6.4) AU/ml compared with 21.7 (6.3) AU/ml in those without evidence of reinfarction (p = 0.032). CONCLUSION: Both raised PAI-1 activity on admission and diabetes were associated with a reduced likelihood of enzymatic evidence of reperfusion after thrombolytic therapy. Increased PAI-1 activity on day 3 was associated with an increased risk of reinfarction. Diabetic patients had higher PAI-1 activity on admission. This may partly explain their reduced likelihood of reperfusion.

Autoantigens↗
PubMed1993

Plasminogen activator inhibitor activity in diabetic and nondiabetic survivors of myocardial infarction.

Recent studies suggest that plasminogen activator inhibitor (PAI-1) may be a risk factor for recurrent myocardial infarction. We measured PAI-1 activity and antigen and tissue-type plasminogen activator (t-PA) antigen in 35 (20 nondiabetic and 15 diabetic) subjects with no clinical or electrocardiographic evidence of ischemic heart disease and in 74 (50 nondiabetic and 24 diabetic subjects) who had survived a myocardial infarction in the preceding 6-24 months. Levels of PAI-1 activity (18.7 +/- 5.6 versus 12.0 +/- 3.8 arbitrary units [AU] per milliliter, p = 0.001) and t-PA antigen (7.0 +/- 1.9 versus 4.6 +/- 2.0 ng/mL, p = 0.001) were significantly higher in diabetic compared with nondiabetic control subjects. Survivors of myocardial infarction had higher levels of PAI-1 activity and antigen and t-PA antigen than control subjects, and the diabetic survivors had higher levels of PAI-1 activity (25.3 +/- 6.7 versus 20.1 +/- 7.1 AU/mL, p = 0.004) and t-PA antigen (10.6 +/- 4.3 versus 8.4 +/- 3.3 ng/mL, p = 0.03) than the nondiabetic survivors. No difference in PAI-1 antigen levels was found between the diabetic subjects and either the nondiabetic control subjects or survivors of myocardial infarction. After venous occlusion in control subjects, there was a significant increase in PAI-1 antigen (mean 26.7%, range 14.1-58.1% in nondiabetics and mean 25.2%, range 6.2-39.7% in diabetics) and t-PA antigen (mean 78.3%, range 13.6-186.2% for nondiabetic and mean 40.7%, range 17.5-76.2% for diabetic subjects), but in the survivors of myocardial infarction, no significant effect of venous occlusion was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Carmustine toxicity presenting as a lobar infiltrate.

Carmustine is a chemotherapeutic agent frequently employed in the treatment of malignant brain tumors. The side effect of pulmonary fibrosis occurs in 20 to 30 percent of patients receiving this drug. Herein we report a case of presumed carmustine-induced pulmonary fibrosis occurring with an unusual lobar distribution.

Adult↗
PubMed1993

Dose titration of sustained-release recombinant bovine somatotropin in lactating dairy cows.

Lactating dairy cows (n = 264) were used in seven dose titration experiments at four geographic locations in the United States. A sustained-release formulation of recombinant bST was evaluated for a 30-wk treatment period that began 14 wk postpartum. The first series of four experiments evaluated doses of 0, 140, 350, or 700 mg of bST/14 d (series A); the second series evaluated doses of 0, 56, 140, or 350 mg of bST/14 d (series B). Milk yield, DMI, milk composition, body condition, health, and reproductive parameters were measured. Multiparous cows in series A that were administered 700 mg of bST/14 d yielded 3.0 kg/d more milk and 3.5% FCM than control cows. When all seven experiments were combined, multiparous cows that were administered 350 mg of bST/14 d yielded 2.7 and 2.6 kg/d more milk and 3.5% FCM than control cows. Dry matter intake was not significantly affected by bST administration. In series A, an increase in milk yield with no increase in DMI resulted in lower adequacy of dietary NEL and CP to meet maintenance and yield requirements among multiparous cows administered 700 mg of bST/14 d. Primiparous cows that were administered bST in series A and both parity groups in the combined seven experiments were not different from control cows in the adequacy of dietary NEL or CP to meet maintenance and yield requirements. No adverse effects of bST on health parameters were significant, and doses of 350 mg of bST/14 d or less caused no changes in reproductive parameters. Conception rate was decreased by administration of 700 mg of bST/14 d. These data suggest that 350 mg of bST/14 d increased yields of milk and FCM with no adverse effects on DMI, health, or reproduction in dairy cows.

Animals↗
PubMed1992

Lactational response of Jersey cows to bovine somatotropin administered daily or in a sustained-release formulation.

Twenty-four Jersey cows were administered either 0 or 15.5 mg of bST/d or 310 mg of bST/14 d to determine the effect on milk yield, milk composition, feed intake, and body weight. Administration of bST was from wk 14 through 42 postpartum. Cows were housed in a tie-stall barn and fed for ad libitum intake a TMR adjusted to one of two energy protein densities according to milk yield. Milk yield of cows administered bST daily or by sustained-released vehicle increased 27.6 and 24.7%, respectively, over that of control cows; FCM increased by 30.3 and 26.7%. Percentages of fat and protein in milk were unaffected by bST treatment. Dry matter intake of cows administered bST was greater than that of control cows, whether expressed as kilograms per day or as a percentage of body weight. Apparent efficiency of yield increased in cows administered bST. No significant change in body weight occurred; however, cows administered bST had lower body condition scores at 42 wk postpartum. This trial demonstrated comparable effects of bST on lactational performance when administered daily or in a 14-d sustained-release vehicle.

Animals↗
PubMed1991

A data model for intensive care.

The paper describes a model of clinical management data in a typical general intensive care unit, intended as a generic database specification for advanced intensive care computer systems. The data model was developed as part of the INFORM project. The INFORM project is summarised and the relevance of the data model to the objectives of the project are discussed. An object oriented extension to the entity relationship diagram methodology is presented. The methodology is illustrated with reference to some specific aspects of the data model including: the principle clinical entities; classification of patient state related data and the homogeneous patient group system. It is suggested that such a model will contribute to the better understanding of the data in the system, to the better design of future intensive care computer systems and to the setting of standards for medical data.

Decision Support Systems, Management↗
PubMed1991

Angiotensin converting enzyme inhibitors and magnesium conservation in patients with congestive cardiac failure.

OBJECTIVE: To investigate whether angiotensin converting enzyme inhibitors reduce diuretic induced magnesium excretion in patients in congestive cardiac failure. DESIGN: Cohort analytic study. SETTING: A London district general hospital. SUBJECTS: Thirty four patients with chronic congestive cardiac failure caused by ischaemic heart disease or cardiomyopathy selected consecutively from inpatients under the care of two consultant cardiologists. Nineteen patients (group 1) on diuretics alone were compared with 15 patients (group 2) taking diuretics plus either enalapril or captopril. All drug regimens were stable for at least three months before the study. Patients with impaired renal function (plasma creatinine greater than 120 mumol/l) were excluded. INTERVENTIONS: An intravenous loading dose of magnesium sulphate was given to minimise the variability in baseline magnesium state. MAIN OUTCOME MEASURE: Total urine magnesium excretion and creatinine clearance in 24 hour urine collections. RESULTS: Plasma magnesium was similar in the two groups. However, 24 hour urine magnesium excretion was significantly lower in group 2 than in group 1. Furthermore, creatinine clearance was also significantly lower in group 2 and correlated strongly with magnesium excretion. There was no such relation in group 1. There was no difference in fractional clearance of magnesium between groups. CONCLUSION: Angiotensin converting enzyme inhibitors have an important magnesium conserving action, possibly via their effect on glomerular filtration rate.

Aged↗
PubMed1991

Achieving excellence in nursing.

The critical shortage of nurses has placed a heavy burden on managers. Because they are responsible for ensuring that pediatric staff members maintain high professional standards, the promotion excellence within the staff remains imperative; it is essential that managers assist themselves and others to strive for excellence. How do you strive for excellence? A commitment to excellence requires a lifelong commitment to nursing, research, learning, scholarship, and personal balance and well-being. Pursuit of excellence in nursing is difficult, especially in a society marked by its satisfaction with mediocrity. Yet by this pursuit, not only will the nurse benefit, but so will the staff, the children, and maternal-child nursing.

Clinical Competence↗
PubMed1988

Biophysical studies of the cellular elements of the rabbit carotid body.

The carotid body is a major sensor of oxygen partial pressure in the arterial blood, and plays a role in the control of respiration. Despite extensive investigation of the structure, the cellular basis of the transduction mechanism remains poorly understood. We have developed a preparation of freshly dissociated cells from the rabbit carotid body, in which two cell types may be identified using morphological criteria. The preparation allows application of the patch clamp technique to characterize the properties of the cells which have otherwise proved difficult to study in situ. Carotid bodies of rabbits were dissociated using a combination of enzymatic and mechanical procedures. The dissociated preparation obtained consisted of clusters of spherical or ovoid cells of 12-15 microns in diameter and a distinct population of spherical cells of 8-10 microns diameter. Electron microscopic techniques were used to identify the cells present in the preparation. Again two populations of cells could be distinguished. A population of cells 10-12 microns in diameter, often found in clusters, possessed the dense-cored vesicles characteristic of Type I cells, while a population of smaller cells (diameter 5-7 microns) had peripherally condensed nuclear chromatin and fine cytoplasmic surface extensions characteristic of Type II cells. Patch clamp study of the cells showed that they represent two electrophysiologically distinct populations. The larger cells, corresponding to Type I cells, were found to be excitable, generating fast, sodium-dependent action potentials that were recorded both in the cell attached and whole cell recording configurations. The smaller Type II cells did not generate action potentials. Voltage clamp study of Type I cells allowed definition of a range of voltage-gated currents. These included an inactivating, tetrodotoxin-sensitive inward sodium current, a high threshold sustained inward calcium current, and outward potassium currents. A component of the outward current showed a dependence on voltage-gated calcium entry, and was blocked by cobalt or cadmium. Of the calcium-dependent current, a component was sensitive to apamin, and the remaining current was blocked by tetraethylammonium. Type II cells showed only a high threshold outward potassium current. These studies have thus revealed an electrophysiological differentiation that parallels the morphological differentiation of the cells of the carotid body. The Type I cell is essentially neuron-like in its properties, while the Type II cell appears to have properties resembling those of glial elements elsewhere in the nervous system.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗