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Biomedical subjects

C D Morgan

Publications and source records attributed to C D Morgan.

At least 73 records · Page 4Linked to original sources
PubMed1992

Thrombolysis in unstable angina. Randomized double-blind trial of t-PA and placebo.

BACKGROUND: Because coronary thrombosis is important in the pathogenesis of unstable angina and correlates with in-hospital cardiac events, we hypothesized that thrombolytic therapy would decrease cardiac events. METHODS AND RESULTS: We randomized 70 patients with unstable angina to tissue-type plasminogen activator (t-PA) (0.49 MU/kg for 1 hour followed by 0.07 MU/kg per hour for 9 hours) or placebo. All patients received full doses of intravenous heparin for 96 hours and aspirin (325 mg beginning at 72 hours). The primary end points of the study were in-hospital death, myocardial infarction, and urgent revascularization. Three secondary end points were also evaluated. Myocardial perfusion was assessed with resting planar thallium scintigraphy 90 minutes after initiation of therapy. Silent ischemia was assessed with 48-hour Holter monitoring for ST shift beginning at time of initiation of drug therapy. Coronary angiography was performed at 18 +/- 6 hours and analyzed quantitatively to assess the stenosis responsible for unstable angina, the presence of intraluminal filling defects consistent with intracoronary thrombus, and stenosis morphology and severity. There was no difference in total in-hospital cardiac events between patients receiving t-PA (5% or 14%) and those receiving placebo (7% or 20%) (p = 0.83). Resting thallium defects were larger in the patients receiving t-PA than in those receiving placebo (130 +/- 118 versus 76 +/- 84 degrees, p less than 0.04), and this difference persisted when corrected for previous infarction. Although the numbers of patients with ST shift were similar, the duration of ST shift was significantly longer in the patients receiving t-PA than with placebo (20 +/- 46 versus 3 +/- 10 minutes, p less than 0.045). The frequency of intracoronary thrombi in patients with stenoses greater than 50% was significantly less in patients treated with t-PA (11 of 22, 52%) as compared with placebo (23 of 25, 92%) (p = 0.002), but there was no significant difference in minimal lesion cross-sectional area (0.49 +/- 0.42 versus 0.57 +/- 1.08 cm2, p = 0.75) or ulceration index (0.79 +/- 0.16 versus 0.77 +/- 0.15, p = 0.71) of the culprit artery. CONCLUSIONS: We conclude that a prolonged infusion of t-PA in unstable angina reduces intracoronary thrombi but does not significantly decrease in-hospital cardiac events. The sample size, however, does not provide sufficient power to rule out a treatment effect. Paradoxically, there appears to be an increase in ST shift and worsening of myocardial perfusion with t-PA compared with therapy with heparin alone.

Aged↗
PubMed1992

Maternal serum screening for fetal Down syndrome in women less than 35 years of age using alpha-fetoprotein, hCG, and unconjugated estriol: a prospective 2-year study.

OBJECTIVE: To evaluate prospectively maternal serum screening with alpha-fetoprotein (AFP), hCG, and unconjugated estriol (uE3) as a screen for fetal Down syndrome. METHODS: Women less than 35 years of age were offered screening between 15-20 weeks' gestation. Screening results calculated by an algorithm to be equal to or greater than 1:274 (the risk of a 35-year-old for fetal Down syndrome at the second trimester) were considered positive. If gestational age was confirmed by ultrasonography, genetic counseling and amniocentesis were offered. RESULTS: In the first 2 years of our program, 9530 women were screened, of which 686 (7.2%) were found to be screen-positive. Ultrasonographic examination explained the abnormal values in 379 (4.0%). The remaining 307 (3.2%) received genetic counseling and 214 (2.2%) elected amniocentesis or CVS. Four cases of fetal Down syndrome and one de novo chromosomal marker were detected. In three additional cases of fetal Down syndrome, triple-analyte screening failed to identify the pregnancies to be at increased risk. None of the seven cases of fetal Down syndrome would have been detected through screening with maternal serum alpha-fetoprotein (MSAFP) and age alone. CONCLUSIONS: Measurement of MSAFP, hCG, and uE3 in women less than 35 years old is an effective screening test for fetal Down syndrome, with a sensitivity of 57% in our study and an amniocentesis rate (false-positive rate) of 3.2%.

Adult↗
PubMed1992

Reverse redistribution on exercise thallium scintigraphy: relationship to coronary patency and ventricular function after myocardial infarction.

OBJECTIVE: To define prevalence, pathophysiology and relation to thrombolytic therapy of reverse redistribution (appearance of a new, or worsening of an existing, scintigraphic defect on 4 h delayed images compared with the stress thallium image). DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Referral centre. PATIENTS: Sixty-three patients with acute myocardial infarction. INTERVENTIONS: Tomographic exercise thallium scintigraphy, radionuclide angiography, and quantitative coronary angiography. MAIN RESULTS: Tomographic exercise thallium scintigraphy performed at day 10 revealed fixed defects in 15 patients, reversible defects in 22 patients and reverse redistribution in 26 patients; no difference in treatment assignment (tissue plasminogen activator versus placebo) was found among the three groups. Left ventricular function was similar in patients with fixed or reversible defects and reverse redistribution; global ejection fraction was 48 +/- 14, 51 +/- 10 and 48 +/- 5%, respectively, and regional infarct ejection fraction was 36 +/- 15, 40 +/- 13 and 37 +/- 18%, respectively. However, nitroglycerin administration resulted in a significantly greater improvement in regional ejection fraction in reverse redistribution patients (5 +/- 4%) than that in patients with fixed defect (2 +/- 5%, P < 0.05) or reversible defects (3 +/- 5%, P < 0.05). The infarct-related artery had a greater cross-sectional area in reverse redistribution patients (1.5 +/- 1.42 mm2) compared with those with reversible defects (0.50 +/- 0.26 mm2, P < 0.05), but was similar to fixed defect patients (1.04 +/- 0.88). CONCLUSIONS: Reverse redistribution on tomographic thallium scintigraphy is a frequent phenomenon (occurring in 40% of patients following acute myocardial infarction) and is independent of thrombolytic therapy. Patients with reverse redistribution have a more widely patent infarct-related artery and similar ventricular function, but significantly greater functional improvement following nitroglycerin administration compared with those with reversible or fixed defects. These data suggest myocardial salvage within the infarct zone in some patients with reverse redistribution.

Animals↗
PubMed1991

Does unexplained second-trimester (15 to 20 weeks' gestation) maternal serum alpha-fetoprotein elevation presage adverse perinatal outcome? Pitfalls and preliminary studies with late second- and third-trimester maternal serum alpha-fetoprotein.

Several reports have suggested that persons with an unexplained maternal serum alpha-fetoprotein elevation at 15 to 20 weeks' gestation are at an increased risk for a variety of other pregnancy complications (e.g., preeclampsia) and adverse perinatal outcomes (e.g., fetal death, low-birth-weight infants). However, ascertainment biases could explain some of these reported findings, and predictive value of unexplained elevated maternal serum alpha-fetoprotein levels in the prediction of pregnancy complications seems limited. If elevated second-trimester levels were truly predictive of pregnancy complications, we reason that third-trimester levels could prove even more useful. We thus studied late second-trimester and early third-trimester (24 to 36 weeks' gestation) maternal serum alpha-fetoprotein levels with the same enzyme immunoassay we use to evaluate routine second-trimester (15 to 20 weeks' gestation) levels. Values rose up to 32 weeks and fell slightly thereafter. Variance was greater than at 15 to 20 weeks but not so great as to preclude clinical usefulness in the third trimester. Of 279 women with a normal (0.4 to 2.49 multiples of the median) maternal serum alpha-fetoprotein value at 15 to 20 weeks' gestation, 270 (96.8%) showed levels in the same range later in gestation; however, none of six singleton pregnancies with unexplained maternal serum alpha-fetoprotein levels greater than 2.50 multiples of the median at 15 to 20 weeks' gestation showed maternal serum alpha-fetoprotein levels in this range at 24 to 36 weeks' gestation. The relationship between second- and third-trimester maternal serum alpha-fetoprotein levels in abnormal pregnancies remains to be elucidated in a large sample. Thus we are conducting not only cohort but also cross-sectional studies. Preliminary findings suggest that women with preterm premature rupture of membranes or with premature labor show elevated late second-trimester and early third-trimester maternal serum alpha-fetoprotein levels; however, larger sample sizes are necessary.

Female↗
PubMed1991

Coronary patency, infarct size and left ventricular function after thrombolytic therapy for acute myocardial infarction: results from the tissue plasminogen activator: Toronto (TPAT) placebo-controlled trial. TPAT Study Group.

Infarct size, left ventricular function and infarct-related coronary artery patency were examined in 108 patients who took part in a previously reported placebo-controlled trial of recombinant tissue-type plasminogen activator (rt-PA) in acute myocardial infarction. Coronary angiography was performed 17 +/- 0.8 h after initiation of treatment in 47 patients (group A) or at 10 days in 61 patients (group B). Both groups underwent radionuclide ventriculography 3.8 +/- 0.8 h and again on day 9 after treatment and quantitative thallium scintigraphy on day 8. In group A, the infarct-related artery was patent in 53%; these patients had a smaller global (15.1 +/- 2.5% vs. 25.7 +/- 4.7%, p = 0.029) and regional (14.7 +/- 2.5% vs. 24.1 +/- 4.7%, p = 0.044) fixed thallium defect than did those with an occluded artery. Infarct regional ejection fraction improved by 10.1 +/- 2.1% between early and late studies when the infarct-related artery was patent and by 4.8 +/- 1.4% if it was occluded (p = 0.048); changes in global and noninfarct regional ejection fraction were similar irrespective of perfusion status. Infarct regional ejection fraction and fixed thallium defect were inversely related only when the infarct-related artery was occluded (r = -0.83, p less than 0.0001). In group B, 10 day patency of the infarct-related artery was 67%; there was no difference in patency by treatment assignment or in left ventricular function or infarct size between patients with and without infarct-related artery patency. There was no evidence of an effect of rt-PA therapy beyond that expressed through coronary patency alone in either group A or group B.

Coronary Vessels↗
PubMed1991

The "all-inside" meniscus repair.

The arthroscopic "all-inside" meniscus suturing technique offers the arthroscopist a way of placing vertically oriented sutures through peripheral posterior horn tears located posterocentral without the risks of nerve, vessel, or posterior capsular entrapment inherent in both the "outside-in" and the "inside-out" arthroscopic methods. This technique introduces new instrumentation that allows the surgeon to both place sutures and tie suture knots intraarticularly under arthroscopic control.

Arthroscopy↗
PubMed1991

Rorschach assessment of purging and nonpurging bulimics.

Research in bulimia has flourished in recent years, and yet minimal attention has been devoted to explorations of the bulimic's basic personality organization. We utilized the Rorschach to differentiate between purging and nonpurging bulimics and controls. There were 15 subjects in each group. The Comprehensive System (Exner, 1986) was used for the scoring of the protocols. Statistically significant differences were not found between the two bulimia groups, but interesting trends were detected in the areas of depression, anger, and self-preoccupation. Results appear to be constrained by the low rate of purging behavior. Comparisons between the combined bulimia groups and the controls resulted in solidly characterizing the bulimics as displaying perceptual inaccuracies, disordered thinking, a vulnerability to interpersonal problems, a damaged self-image, and a pessimistic outlook. The strengths of the study were its use of the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev. [DSM-III-R]; American Psychiatric Association, 1987) nonpatients bulimic subtypes and a control group that was comparable in terms of demographics. Future Rorschach studies with bulimics displaying higher frequencies of binging and purging behaviors are suggested.

Adaptation, Psychological↗
PubMed1991

Survey of cardiac pacing in Canada.

UNLABELLED: The status of cardiac pacing in Canada in 1989 was determined from data provided by 62 of 128 physicians surveyed (48% response) and four major manufacturer/distributors. A questionnaire designed for the IXth World Symposium on Cardiac Pacing was used. DEMOGRAPHICS: There were five implant hospitals per million population, 65% community based and 35% university affiliated; 63% of implanters were surgeons. There were 279 new implants and 46 replacement procedures per million population. INDICATIONS: Sinus node disorders accounted for 44.6% of implants, atrioventricular block 43.2% (fixed 24.4%, intermittent 12.0%, incomplete 6.8%), tachycardias 2.9%, drug-induced bradycardia 3.1%, and other (including automatic implantable cardioverter defibrillators) 6.2%. TECHNOLOGY: Single chamber units were implanted in 78.6% of patients, and dual chamber in 22.7%, and 19.5% of the total were rate-adaptive. Unipolar leads were used in 57.1% of atrial and 53.2% of ventricular insertions; 40.4% of atrial and 5.8% of ventricular leads were active fixation. The pervenous sheath introducer technique was used in 64.9% of lead insertions. PERIOPERATIVE: Major complications occurred in 2.6% of single and 6.8% of dual chamber primary implants, but mortality was less than 0.1%; 8.4% of replacements were unanticipated; there was no known death from malfunction. Mean hospital stay was 2.7 days for primary implants and 1.4 days for replacement/revisions. CONCLUSIONS: Comparison with prior surveys (1979, 1981, 1985) reveals: increased physician response to the survey questionnaire; relatively stable electrocardiographic indications for implant; a modest increase of new implants per million; continued decrease in replacements; an increase in dual chamber and rate-adaptive pacing; and increased use of active fixation and bipolar electrodes in both atrium and ventricle.

Arrhythmias, Cardiac↗
PubMed1989

Tissue plasminogen activator: Toronto (TPAT) placebo-controlled randomized trial in acute myocardial infarction.

The efficacy and safety of recombinant tissue plasminogen activator (rt-PA) administered on a dosing per weight basis was evaluated in a randomized, placebo-controlled, double-blind trial in 115 patients with acute myocardial infarction. The principal outcomes were global and regional left ventricular function in the distribution of the qualifying myocardial infarction, determined 9 days after the onset of symptoms. Global and regional ejection fraction values were significantly better for patients treated with rt-PA than for placebo-treated patients (the differences were 5.8 +/- 2.7% units [p = 0.017] and 7.1 +/- 3.1% units [p = 0.012], respectively). This benefit was also evident from visual assessment of left ventricular segmental wall motion. After adjustment for differences in important prognostic variables at baseline, the estimates of treatment effect were 4.0 +/- 2.4% units (p = 0.048) for global and 4.3 +/- 2.6% units (p = 0.047) for regional ejection fraction. Early patency of the infarct-related vessel was demonstrable in 7 (29%) of 24 placebo-treated patients and 18 (78%) of 23 rt-PA-treated patients, whereas 15 (56%) of 27 patients in the placebo group and 23 (72%) of 32 in the rt-PA group had a patent infarct-related vessel at hospital day 9. There was no significant difference in irreversible or reversible defect size as assessed by thallium scintigraphy on day 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Double-Blind Method↗
PubMed1989

Speech dysfunction of obstructive sleep apnea. A discriminant analysis of its descriptors.

We have previously demonstrated a relationship between abnormal speech and obstructive sleep apnea in a small subject sample. The present study was designed to replicate the previous one with a much larger population, analyze the perceptual characteristics of the speech quality, and determine the degree to which each of three descriptors of speech abnormality contributed to the perception of speech abnormality. Ten graduate students in speech pathology listened in two 1.5 hour sessions to 252 random speech samples presented on a master tape. There were 81 subjects comprised of 27 sleep apnea patients, 27 matched chronic obstructive pulmonary disease control patients, and 27 matched normal control subjects. Rating the speech along an equally-appearing interval scale from 1 to 7, the judges heard abnormal resonance, articulation or phonation in 74 percent of the sleep apnea subjects, 53 percent of the COPD subjects, and 7 percent of the normal subjects (significant difference by chi 2 test at the .01 level of confidence). Discriminant function equations based on these speech descriptors correctly identified 96.3 percent of the normal subjects and 63.0 percent of the sleep apnea subjects. Analysis of abnormal speech resonance, articulation and phonation may identify obstructive sleep apnea or may provide insight into its pathology.

Adult↗
PubMed1989

Catheter drainage of the pericardium: its safety and efficacy.

A retrospective chart review identified 46 consecutive patients who underwent catheter drainage of the pericardium over 3 years. Cardiac tamponade was present in the majority of patients, and the underlying cause was tumour metastasis in 72%. Pericardial catheterization was accomplished by the Seldinger technique using the subxiphoid approach. Catheter insertion was successful in 42 of the 46 patients, and in only 1 was there a serious complication. The mean duration of catheter drainage was 3 days. The pericardial space was successfully drained in all but one patient, who subsequently required surgery. Intrapericardial chemotherapy was administered in 27 patients. There was no instance of catheter-associated sepsis. Supraventricular arrhythmias occurred in 19% of patients, but all were managed medically. There were no late complications attributable to the period of drainage. The authors conclude that catheter drainage of the pericardium is a safe and effective means of providing definitive drainage of the pericardial space.

Cardiac Tamponade↗
PubMed1987

Arthroscopic Bankart suture repair: technique and early results.

Twenty-five recurrent traumatic unidirectional anterior shoulder dislocators were stabilized arthroscopically with a transglenoid absorbable suturing technique. A Bankart lesion was documented and repaired in all cases. Postoperative follow-up averaged 17 months (range 1 year to 30 months). All results were rated excellent. All patients achieved full, painless range of motion (ROM), and no instances of postoperative instability occurred. There were no complications. The details of the operative technique are described.

Adolescent↗