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Biomedical subjects

J C Lincoln

Publications and source records attributed to J C Lincoln.

At least 19 recordsLinked to original sources
PubMed1997

Effects of age and ischemic times on biochemical evidence of myocardial injury after pediatric cardiac operations.

INTRODUCTION: The vulnerability of pediatric myocardium to ischemia is poorly documented in the clinical setting. METHODS: Serial measurements of serum concentrations of myoglobin, the MB isoenzyme of creatine kinase, and cardiac troponins T and I and their respective areas under the curve were obtained, with particular reference to age and ischemic time, in 80 children undergoing cardiac operations. Sixteen (the control group) did not require cardiopulmonary bypass and 64 did. RESULTS: In the control group there were increases (p < 0.01) in myoglobin and creatine kinase MB isoenzyme but no increase in cardiac troponin T or I; by contrast, the group treated with cardiopulmonary bypass had significant increases in all four markers but with differing temporal patterns. Younger age (especially < 12 months) was a highly significant explanatory variable only for the release of cardiac troponins T and I, and ischemic time was a significant explanatory variable for the release of creatine kinase MB isoenzyme, cardiac troponins T and I, but not myoglobin. In comparison with previous studies in adults, creatine kinase MB and cardiac troponin T concentrations were three times greater in children than in adults. CONCLUSIONS: This study supports the specificity of cardiac troponins T and I as markers of myocardial injury after pediatric cardiac operations and defines the importance of age and ischemic time in determining their release. In comparison with previous data in adults, our results raise the possibility that the pediatric heart may be more vulnerable to the effects of ischemia and reperfusion. Cardiac troponins will permit comparison of new myocardial protective strategies or other potentially therapeutic myocardial interventions.

Adult↗
PubMed1996

Vulnerability of paediatric myocardium to cardiac surgery.

OBJECTIVE: Myocardial injury is an important cause of mortality and morbidity after paediatric cardiac surgery. Data obtained from studies in animals imply that juvenile myocardium is more resistant to the effects of ischaemia and reperfusion than adult myocardium but there is little confirmatory evidence in the clinical setting. DESIGN: Prospective observational study of biochemical markers of myocardial injury in a paediatric population undergoing cardiac surgery. SETTING: Tertiary referral centre for paediatric cardiac surgery. PATIENTS: Forty patients undergoing paediatric cardiac surgery of varying complexity including closure of atrial and ventricular septal defects and arterial switch for simple transposition. A control group included patients undergoing thoracotomy for closure of a patent ductus arteriosus or repair of a coarctation. INTERVENTIONS: Serial measurements of myoglobin, the MB isoenzyme of creatine kinase (CK-MB), and the highly specific markers of myocardial damage cardiac troponin T (cTnT) and I (cTnI) were made before and 1, 6, 24, and 48 to 72 hours after operation. RESULTS: There were significant increases in myoglobin and CK-MB, but not cTnT or cTnI, in the control group. There were significant increases in the four biochemical markers in all the cardiac operations but especially in the ventricular septal defect and transposition group. Increases in CK-MB and cTnT were about five times greater than those previously reported in adult patients. CONCLUSIONS: (i) Cardiac troponins are more specific markers of myocardial injury in paediatric cardiac surgery than myoglobin and CK-MB. (ii) Paediatric myocardium seems to be more vulnerable to injury during cardiac surgery than adult myocardium.

Adult↗
PubMed1994

Role of factor XII in thrombin generation and fibrinolysis during cardiopulmonary bypass.

During cardiopulmonary bypass, thrombin is generated, which is thought to be initiated by activation of factor XII on the surface of the bypass equipment. We present a patient with severe factor XII deficiency who underwent cardiac surgery. As much thrombin was formed during cardiopulmonary bypass (measured by the prothrombin activation fragment F1 + 2 and thrombin-antithrombin complexes) as in normal patients, showing that factor XII was not necessary for thrombin generation. Factor X, but not factor IX, was activated (as measured by their activation peptides), and this activation correlated with F1 + 2 and thrombin-antithrombin complexes, suggesting that the tissue-factor/factor-VIIa pathway is the trigger for thrombin formation.

Antithrombin III↗
PubMed1985

Sympathoadrenal function during cardiac operations in infants with the technique of surface cooling, limited cardiopulmonary bypass, and circulatory arrest.

The sympathoadrenal response to surface cooling, limited cardiopulmonary bypass, and deep hypothermic circulatory arrest was investigated in 22 infants undergoing correction of congenital heart defects. Surface cooling to 26 degrees C was associated with a significant rise in plasma epinephrine and norepinephrine levels. Both levels fell during the period of core cooling on bypass, presumably because of hemodilution. Following the period of circulatory arrest there was a rise in both catecholamine levels that correlated nonlinearly with the duration of circulatory arrest. The catecholamine levels remained high after rewarming until the chest was closed. The results suggest that this type of surgical procedure produces severe sympathoadrenal stress. The extremely high values found in the postarrest period in some patients, who had had a long period of arrest (greater than 40 minutes), may indicate hypoxic stress. The biological effect of high circulating plasma catecholamines during hypothermia is difficult to assess. The heart rate response to plasma catecholamine levels tended to diminish on cooling in our patients.

Cardiopulmonary Bypass↗
PubMed1983

Nuclear proteins associated with gene expression in mouse plasmacytoma cell lines.

Nucleoplasmic and non-histone chromatin proteins from two unrelated and four related mouse plasmacytoma cell lines have been analysed by biosynthetic labelling with [35S]-methionine followed by one- and two-dimensional polyacrylamide gel electrophoresis. We have attempted to find a relationship between the patterns of nuclear proteins and gene expression in mutant plasmacytoma cell lines. The majority of nuclear proteins are common to all of the cell lines studied as would be expected if the majority of nuclear proteins are concerned with functions common to all plasma cells. There are, however, both qualitative and quantitative differences in the nuclear protein patterns of mutant and parent cell lines which appear to correlate with differences in gene expression. The turnover of nuclear proteins in two of the cell lines, MOPC 315.40 (IgA producer) and MOPC 315.32 (lambda 2 chain producer) was studied using pulse-chase techniques.

Animals↗
PubMed1983

Sleeve lobectomy (lobectomy and bronchoplasty) for bronchial carcinoma.

We present a series of 90 patients who underwent sleeve lobectomy for malignant bronchial tumors at the Brompton Hospital, London, between 1964 and 1974. The operative mortality was low (1%), and technical complications were infrequent. Bronchial stenosis, which occurred in 6% of patients, was due to recurrence of tumor in 4% and cicatrization in 2%. The majority of patients had squamous cell carcinomas of the upper lobe (76/90). In this group, the 5-year survival was 71% when the hilar lymph nodes were clear of tumor at the time of operation and 17% when the hilar lymph nodes were involved. Because these 5-year survival figures suggest that tumor-free survival is not significantly compromised by this conservative approach, we believe that sleeve lobectomy rather than pneumonectomy should be considered the operation of choice for squamous cell carcinomas of the upper lobe orifice involving the main bronchus.

Adult↗
PubMed1983

Interrupted aortic arch--anatomical features of surgical significance.

Analysis of 26 autopsy specimens with interruption of the aortic arch has led to a clearer understanding of the vital importance of associated cardiovascular abnormalities. In all cases there was an associated patent ductus arteriosus "supporting" the distal systemic circulation. "Proximal" septal defects, 22 ventricular septal defects and 3 aorto-pulmonary windows, were found in all but one specimen. The infundibular component of the ventricular septum was displaced posteriorly and leftward in 9 hearts resulting in significant left ventricular outflow obstruction in 8. In one specimen the infundibular septum was displaced anteriorly giving the effect of a "Fallot type" obstruction to the right ventricular outflow tract. Abnormal ventriculo-arterial connections were found in 7 hearts; 2 with discordant connection, 2 with double outlet, and 3 with single outlet of the heart. In 6 specimens there was an aberrant origin of the right subclavian from the distal aorta passing behind the esophagus to the right side. Various other arterial abnormalities were identified including a truncus arteriosus with separate but "transposed" origins of the pulmonary arteries. In short, in these hearts there were no examples of the rare situation where aortic arch interruption exists in isolation. This study therefore makes it very clear that a detailed understanding of associated anatomical abnormalities must accompany any attempt at surgical correction. Certainly in many of these cases management of the associated lesion will present more of a challenge than the difficult problem of dealing with the interrupted arch itself.

Abnormalities, Multiple↗
PubMed1982

Recognition of imperforate atrioventricular valves by two dimensional echocardiography.

The majority of hearts in which selective right or left atrial angiography shows no direct communication between one atrium and a ventricular chamber are considered to be examples of atresia of the right or left atrioventricular valves. Most patients presenting with the clinical features of tricuspid atresia have an absent right atrioventricular connection, while those with features of mitral atresia and a normal aortic root frequently have an absent left atrioventricular connection. By studying 67 patients using two dimensional echocardiography we have identified 12 in whom there was an imperforate atrioventricular valve and not an absent atrioventricular connection. Thus, in 44 hearts with the angiographic features of tricuspid atresia, 36 had absence of the right atrioventricular connection and six had an imperforate right atrioventricular valve. In the latter, four were examples of atrioventricular concordance and two were univentricular hearts of left ventricular morphology in which the mode of atrioventricular connection was through one perforate and one imperforate valve. Similarly, 17 out of 23 cases of mitral atresia had absence of the left atrioventricular connection. The remaining six had an imperforate left atrioventricular valve which was associated with atrioventricular concordance in two patients and with double inlet univentricular heats in four patients.

Child↗
PubMed1982

Right lung agenesis. A case report.

This report describes a combination of a ventricular septal defect and partial anomalous pulmonary venous drainage in an infant with right lung agenesis. Unilateral agenesis of the lung has been rarely described. Although this condition is compatible with long survival, morbidity and mortality are increased by the associations with other malformations both intra- and extracardiac. In unilateral lung agenesis although there is a compensatory increase in volume of the single lung, there is a reduction in the number of branches of the pulmonary artery and the whole right ventricular output passes through a reduced vascular bed. In isolated unilateral agenesis of the lung, pulmonary hypertension is present in about 19% of cases, while in patients with additional left to right shunt the incidence is 88%. The basic condition of increased pulmonary blood flow (single lung) and the undiagnosed partial anomalous pulmonary venous drainage may explain why the early closure of the ventricular septal defect did not prevent the progressive pulmonary vascular disease. We discuss shortly Tolazoline as pulmonary vasodilator.

Heart Septal Defects, Ventricular↗
PubMed1981

Histamine release from human right atrium.

Histamine release has been detected biologically after exposure of human right atrial biopsy samples to compound 48/80. Human right atrial samples contain large quantities of histamine, 1035 +/- 65 ng/g fresh weight. Exposure of untreated electrically paced atrial strips to compound 84/80, 300 micro/ml, caused an increase in the force of atrial contraction similar to that caused by histamine. Pretreatment of strips with cimetidine, 3.16 x 10(-5) M, prevented the inotropic response to compound 48/80. It is concluded that mast cell degranulation in human atrial tissue can cause sufficient release of histamine to modify the function of the heart.

Heart Atria↗
PubMed1981

The use of tolazoline hydrochloride as a pulmonary vasodilator in potentially fatal episodes of pulmonary vasoconstriction after cardiac surgery in children.

Infants and children with highly reactive pulmonary vasculature may die of an acutely increased pulmonary vascular resistance (PVR) during or after correction of congenital heart defects. Fifteen patients, 11 infants ages 2--12 months (mean 5.3 months) and 4 children ages 2--10 years (mean 5.8 years), were treated with tolazoline to reduce an acutely elevated PVR during or after operation. Five patients had total anomalous pulmonary venous drainage, six had ventricular septal defect and four had truncus arteriosus. Preoperatively, the ratio of systolic pulmonary artery pressure to systemic artery pressure (PAP/SAP) was 0.57--1.54 (mean 0.93), and PVR was 1.8--20 units/m2 (mean 6.2 units/m2). The pulmonary artery pressure was monitored postoperatively by pulmonary artery lines placed at surgery (12 patients) or by balloon flotation catheters (two patients). Acute elevations in PAP/SAP accompanied by clinical deterioration occurred during attempted withdrawal from cardiopulmonary bypass in three patients, during apparently optimal ventilation postoperatively in eight patients, and after withdrawal of ventilatory support in four patients. Administration of tolazoline as a bolus (1--2 mg/kg) followed by infusion of 1--2 mg/kg/hour resulted in a rapid and sustained decrease in PAP/SAP, from 1.00 +/- 0.18 (mean +/- SD) to 0.40 +/- 0.09 (p less than 0.001), and was effective management for all these clinical crises. The use of tolazoline may prevent a fatal outcome from acute elevation of PVR in the perioperative period.

Cardiac Surgical Procedures↗
PubMed1980

Pseudolymphoma of the lung: a rare cause of a solitary nodule. A case report and review of the literature.

Pulmonary pseudolymphoma is a rare lesion; only 30 cases have been previously reported. It presents as a solitary nodule which clinically and roentgenographically can resemble bronchogenic carcinoma. A further case is reported in which preoperative needle aspiration cytology played a role in diagnosis. Although the lesion was originally believed to be benign, a review of the literature has revealed the apparent subsequent development of lymphoma in four cases. The significance of this is discussed, and the need for prolonged follow-up is emphasized, since the prognosis of untreated pseudolymphoma is unknown.

Biopsy, Needle↗
PubMed1978

Continuous monitoring of mixed venous oxygen tension (PvO2) in cardiorespiratory disorders.

The development of a miniature polarographic electrode mounted in the tip of a double-lumen plastic catheter has made possible continuous in-vivo monitoring of oxygen tension. Inexpensive catheters of this type have already proved of value as a means of continuously monitoring arterial oxygen tension in the newborn. In 25 patients with acute respiratory failure we found that these catheters could be safely and easily flow-guided into the pulmonary artery. In this way continuous recordings of mixed venous oxygen tension (PvO2) could be made for a period of several days. In our experience a sustained fall of PvO2 below 40 mm Hg proved to be a reliable indicator of respiratory or cardiac deterioration not always obvious by observation. In the patients described, falls of this order were seen after reductions in inspired oxygen concentration, in acute respiratory failure, in accidental underventilation, and in hypovolaemia and cardiac arrythmias. In some very ill patients routine nursing care involving movement of the patient caused pronounced falls of PvO2. Although electrode drift was an occasional problem, this could be checked by intermittent blood-sampling and recalibration if necessary.

Aged↗
PubMed1978

The binding of 14C-labelled acetylaminofluorene to nuclear proteins and DNA.

The covalent binding of acetylaminofluorene (AAF) to rat liver nuclear protein fractions and DNA has been examined after 2 doses of 14C-labelled carcinogen (100 micronCi intraperitoneally) given at 24-h intervals. Most of the AAF (approx. 80%) was bound to the NHP which had the highest specific activity, relatively small amounts were bound to histones, residual proteins and DNA. After 2 weeks the label was more evenly distributed but little remained bound to the DNA. Pre-feeding rats with phenobarbitone (1 mg/ml in drinking water) reduced binding in all fractions. Pre-feeding rats with sodium sulphate (1 mg/ml in drinking water) also slightly lowered the binding to all fractions. Isoelectric focusing analysis (in polyacrylamide gels) of the NHP showed a complex binding pattern with no one component predominantly labelled, variations in the pattern were found after feeding sulphate and phenobarbitone. Normal histone components in the histone fraction (acid extract) contained only 25% of the labelled carcinogen present.

2-Acetylaminofluorene↗