Perinatal risk factors as predictors of developmental functioning

This study examined the relationship between perinatal risk factors and developmental functioning for a referred population of 216 children. A canonical correlation analysis indicated that 31% of the variability in developmental information could be predicted from perinatal events. The results were interpreted as lending support to a multivariate link between perinatal complications and developmental functioning for referred children.

Effect of prophylactic antiarrhythmic therapy on time to implantable cardioverter-defibrillator discharge in patients with ventricular tachyarrhythmias

Implantable cardioverter-defibrillators (ICDs) are being used increasingly for treatment of malignant ventricular tachyarrhythmias. However, ICD discharge is associated with significant morbidity. Antiarrhythmic therapy could reduce the frequency of ICD discharge, but its effect is uncertain. Thus, the effect of antiarrhythmic therapy was evaluated in a randomized trial. Thirty-four patients (32 men and 2 women, average age 60 years) who received an ICD for sustained ventricular tachycardia or fibrillation were entered in the trial and randomized to the best "drug" therapy (group 1; n = 17) or no therapy (group 2; n = 17). After the first ICD discharge, patients were to be crossed over to the alternative treatment arm. Twenty-nine patients had coronary artery disease. The induced arrhythmia was ventricular tachycardia in 33 patients and ventricular fibrillation in 1. Ejection fraction averaged 39%. The 2 groups were well balanced, without differences in demographic variables. In group 1, class I therapy was given to 9 patients and class III to 9. Beta blockade was used in a similar number of patients in groups 1 and 2 (n = 8 and 6, respectively). Time to the first shock or the end of follow-up averaged 143 days (range 1 to 609). During follow-up, 21 patients had a first ICD discharge event (11 in group 1, and 10 in group 2; p = 0.72). Event-free survival in each group was assessed by the Kaplan-Meier method, using the intention-to-treat approach. Overall median time to the first event was 134 days. Time to the first event did not differ between groups (p = 0.66; log-rank test).(ABSTRACT TRUNCATED AT 250 WORDS)

A pilot trial of recombinant desulfatohirudin compared with heparin in conjunction with tissue-type plasminogen activator and aspirin for acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) 5 trial

OBJECTIVES

The purpose of this study was to assess the value of recombinant desulfatohirudin (hirudin) as adjunctive therapy to thrombolysis in acute myocardial infarction.

BACKGROUND

Failure to achieve initial reperfusion and reocclusion of the infarct-related artery remain major limitations of thrombolytic therapy despite aggressive regimens of heparin and aspirin. Hirudin, a direct thrombin inhibitor, has been shown in experimental models to enhance thrombolysis and reduce reocclusion.

METHODS

The Thrombolysis in Myocardial Infarction (TIMI) 5 trial was a randomized, dose-ranging, pilot trial of hirudin versus heparin, given with front-loaded tissue-type plasminogen activator and aspirin to 246 patients with acute myocardial infarction. Patients received either intravenous heparin or hirudin at one of four ascending doses for 5 days. Patients underwent coronary angiography at 90 min and at 18 to 36 h, unless rescue angioplasty was performed.

RESULTS

The primary end point, TIMI grade 3 flow in the infarct-related artery at 90 min and 18 to 36 h without death or reinfarction before the 18- to 36-h catheterization was achieved in 97 (61.8%) of 157 evaluable hirudin-treated patients compared with 39 (49.4%) of 79 evaluable heparin-treated patients (p = 0.07). All four doses of hirudin led to similar findings in the angiographic and clinical end points. At 90 min, TIMI grade 3 flow was present in 105 (64.8%) of 162 hirudin-treated patients compared with 48 (57.1%) of 84 heparin-treated patients (p = NS). Infarct-related artery patency (TIMI grade 2 or 3 flow) was similar in the two groups (82.1% and 78.6%, respectively). At 18 to 36 h, 129 (97.8%) of 132 hirudin-treated patients had a patent infarct-related artery compared with 58 (89.2%) of 65 heparin-treated patients (p = 0.01). Reocclusion by 18 to 36 h occurred in 2 (1.6%) of 123 hirudin-treated patients versus 4 (6.7%) of 60 heparin-treated patients (p = 0.07). Death or reinfarction occurred during the hospital period in 11 (6.8%) of 162 hirudin-treated patients compared with 14 (16.7%) of 84 heparin-treated patients (p = 0.02). Major spontaneous hemorrhage occurred in 1.2% of hirudin-treated patients versus 4.7% of heparin-treated patients (p = 0.09), and major hemorrhage at an instrumented site occurred in 16.3% and 18.6%, respectively (p = NS).

CONCLUSIONS

Hirudin is a promising agent compared with heparin as adjunctive therapy with thrombolysis for acute myocardial infarction, and its evaluation in larger trials is warranted.

Neuropsychological significance of IQ summary scores

A canonical correlation between summary intelligence scores and neuropsychological tests for 423 learning-disabled children was performed. Results showed a significant relationship between WISC-R global intelligence scores and tests of the Halstead-Reitan's Neuropsychological Battery for Older Children (HRNB-C), Rc = .53, p < .001. While measures were found to share commonality, both were found to provide unique information. The clinical implications of these findings were discussed.

Apolipoprotein polymorphisms fail to define risk of coronary artery disease. Results of a prospective, angiographically controlled study

BACKGROUND

Because genetic factors are believed to contribute to the etiology of coronary artery disease (CAD), it has been suggested that DNA polymorphisms at candidate loci might identify individuals at high risk for developing disease. In this regard, apolipoprotein genes represent extremely promising loci because levels of apolipoproteins and their associated lipoproteins represent a major risk factor for CAD, and rare dysfunctional mutations in these genes result in a significant risk for CAD. To date, although some reports indicate that DNA polymorphisms at these loci are associated with increased risk of CAD, other reports have failed to find such associations.

METHODS AND RESULTS

To resolve the question of whether genetic polymorphisms at apolipoprotein loci can be used to identify individuals at increased risk for CAD, we evaluated the distribution of apolipoprotein genetic polymorphisms in a large series of subjects (n = 848) undergoing coronary angiography. Blinded assessment of angiograms was used to discriminate between patients with CAD (> or = 60% stenosis of any major branch, n = 444) and control subjects without disease (< or = 10% stenosis, n = 404). A total of 12 polymorphisms were evaluated at the following loci: apolipoprotein (apo) A-I/C-III/A-IV (five restriction site polymorphisms--Msp I, Pst I, Sst I, Pvu IIa, Pvu IIb), apo B (three restriction site polymorphisms--Xba I, EcoRI, Msp I, plus an insertion/deletion polymorphism), apo A-II (Msp I polymorphism), apo C-II (Taq I polymorphism), and apo E (protein isoforms revealed by DNA analysis). All subjects were of Northern European (primarily Angloscandinavian) descent, and, within each sex, patients and control subjects were of comparable age. All 12 loci were in Hardy-Weinberg equilibrium, with no indication of population heterogeneity. As expected, patients were distinguished from control subjects by their lipid profiles and a higher frequency of known risk factors for CAD. However, analysis by log-linear models indicated that there were no significant associations between apolipoprotein polymorphisms and the risk of CAD (P = .10 to .90). The lack of association was maintained irrespective of whether the analysis was carried out for the entire sample or the contrast was made more stringent by comparing patients most likely to have a genetic component to their disease (ie, young patients with early-onset CAD) with the control subjects least likely to have genetic susceptibility (ie, older control subjects who had ample time to develop CAD).

CONCLUSIONS

Despite the fundamental role of apolipoprotein genes in lipid metabolism, we find no evidence that common genetic polymorphisms of the major apolipoprotein loci have a significant influence on the risk of developing angiographically defined CAD in this representative population. Therefore, at this time we find no support for the hypothesis that mass screening for genetic polymorphisms at candidate loci can reduce the burden of CAD by identifying a substantial proportion of high-risk individuals. Instead, it appears more appropriate to direct attention toward modifying high-risk behaviors to alleviate the consequences of traditional environmental risk factors.

Blood cholinesterase in rats fed an insect resistance apple clone containing a natural cholinesterase inhibitor

A crab apple clone (Malus brevipes 1021), highly resistant to the apple maggot, is being used in breeding programs developing commercial apple cultivars. This study has discovered that this crab apple contains a natural cholinesterase (ChE) inhibitor that caused a 17.5% in vitro inhibition of rat blood ChE activity. This crab apple also showed a relatively high total (titratable) acidity of 1.28%. The commercial, nonresistant, apple cultivar McIntosh was capable of causing a 7.9% inhibition of blood ChE in vitro. The total acidity in McIntosh was 0.45%. A 4-wk feeding study compared 2 groups of 5-wk-old Fischer 344 male rats fed diets containing 45% of either M. brevipes or McIntosh freeze-dried apples to a third (control) group of rats fed a semipurified diet. In vivo blood ChE activities were similar in all groups of rats, as well as hemoglobin, hematocrit, and red blood cell counts. The liver mixed-function oxidase activity through aminopyrine N-demethylase in the rats fed the apple diets was higher than the controls, but p-nitroanisole O-demethylase activity was induced only in the animals fed the maggot-resistant crab apple. Lowered growth with concomitant lowered food intake, in the otherwise healthy rats fed the maggot-resistant crab apple diet, was attributed to the less palatable, highly acidic fruit. This study indicates that the natural ChE inhibitor in the insect-resistant apple M. brevipes is apparently detoxified upon ingestion.

Relation of reperfusion success with anistreplase or alteplase in acute myocardial infarction to body weight. The TEAM-3 investigators

Adjustment in dose based on body size is not recommended currently for thrombolytic regimens, except for a reduction in alteplase (recombinant tissue-type plasminogen activator [rt-PA]) dose for safety reasons in patients with low body weight. It is unresolved how to dose thrombolytic agents in very heavy patients. The study objective was to assess whether patency of the infarct-related artery at 1 day after therapy with anistreplase (anisoylated plasminogen streptokinase activator complex [APSAC]) or rt-PA is adversely affected by increased body weight. Data were analyzed from a double-blind, randomized, comparative study of APSAC (30 U/5 min) versus rt-PA (100 mg/3 hours, adjusted downward for body weight < 65 kg), together with heparin and aspirin, in patients with acute myocardial infarction presenting within 4 hours of symptom onset. Coronary patency, determined at 1 day, was assessed in a blinded fashion, and patency success was correlated with body weight, divided into quintiles. In patients treated with APSAC, coronary patency rates were similar in those in the upper quintile of body weight (> 94 kg; n = 22) and in the low-normal weight group (n = 126) (86 and 90%, respectively, for perfusion grade 2/3 [p = 0.64]; and 82 and 74%, respectively, for grade 3 [p = 0.42]). In contrast, for the rt-PA group, heavy patients (n = 34) achieved significantly lower patency rates (74 vs 89% for grade 2/3 [p = 0.02]; and 59 vs 77% for grade 3 [p = 0.03]). The dose of heparin administered, adjusted to maintain a therapeutic partial thromboplastin time until the 1-day (mean 28 hours) angiogram, was greater in the heavy than in the low-normal weight group (mean +/- SE 39,680 +/- 4,818 vs 30,027 +/- 1,177 U; p = 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

Mortality following ventricular arrhythmia suppression by encainide, flecainide, and moricizine after myocardial infarction. The original design concept of the Cardiac Arrhythmia Suppression Trial (CAST)

OBJECTIVE

To test the hypothesis that in survivors of myocardial infarction, the suppression of ventricular premature depolarizations improves survival free of cardiac arrest and arrhythmic death.

DESIGN

International, prospective, multicenter, randomized, placebo-controlled trial.

SETTING

University and community hospitals.

PATIENTS

A total of 3549 patients with myocardial infarction and left ventricular dysfunction.

INTERVENTION

Administration of encainide, flecainide, moricizine, or placebo to suppress ventricular premature depolarizations.

MAIN OUTCOME MEASURES

Overall survival and survival free of cardiac arrest or arrhythmic death were compared in patients randomized to long-term, active antiarrhythmic drug therapy vs corresponding placebo, using the stratified log rank statistic.

RESULTS

At 1 year from the time of randomization to blinded therapy, 95% of placebo-treated patients vs 90% of active drug-treated patients remained alive (P = .0006). Similarly, at 1 year, 96% of placebo-treated patients vs 93% of active drug-treated patients remained free of cardiac arrest or arrhythmic death (P = .003).

CONCLUSIONS

The suppression of asymptomatic or mildly symptomatic ventricular arrhythmias after myocardial infarction does not improve survival and can increase mortality. Treatment strategies designed solely to suppress these arrhythmias should no longer be followed.

S-cone function in patients with retinitis pigmentosa

PURPOSE

To determine whether short-wavelength-sensitive (S-) cones are more severely damaged in patients with retinitis pigmentosa than long-wavelength-sensitive (L-) and middle-wavelength-sensitive (M-) cones. To determine whether there are differences in the amount of S-cone damage in patients with dominant versus nondominant inheritance patterns. To accomplish these goals with methods that provide information not furnished by previous studies with two-color increment thresholds.

METHODS

Acuity mediated by the S-cones was measured in 56 patients with retinitis pigmentosa, and the electroretinogram (ERG) generated by the S-cones was measured in 11 of these patients. Mixed L- and M-cone acuity, mixed L- and M-cone ERGs, and clinical full-field rod and cone ERGs were obtained for all patients. Data for both dominant and nondominant patient groups were compared with data from age-matched normal subjects.

RESULTS

Only the nondominant group had reduced S-cone acuity, and 43% of patients in this group had selective reduction of S-cone acuity. In this particular sample the dominant and nondominant groups were comparable in clinical full-field ERG parameters and mixed L- and M-cone acuity, so the difference in S-cone acuities is not due to the dominant group having less advanced retinal degeneration. All 11 patients tested had reduced S-cone ERGs, 6 with significantly greater loss in the S-cone ERG than in the mixed L- and M-cone ERG.

CONCLUSIONS

These data provide evidence that retinitis pigmentosa can produce greater loss of S-cones than L- and M-cones, and that this selective loss is primarily seen in patients with nondominant forms of retinitis pigmentosa.

Phenotype and serine esterase production of human cardiac allograft-infiltrating lymphocytes

Human cardiac allograft-infiltrating lymphocytes were studied by in vitro expansion in interleukin-2. Of 28 graft-infiltrating lymphocyte cultures from 17 recipients, 17 were comprised predominantly of CD4+ T cells and 10 predominantly CD8+ T cells; one culture had equal numbers of CD4+ and CD8+ cells. The mean percentages (+/- SE) of T-cell subsets for all cultures were as follows: CD4+, 49% +/- 29%; CD8+, 42% +/- 31%. No correlation was observed between the culture phenotype and histologic findings, length of time from transplantation, or number (or class) of mismatched HLA antigens. N-alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester serine esterase (BLT-SE) is an enzyme associated with intracellular cytotoxic T-cell granules and with target-cell destruction. Sixteen cultures were tested for BLT-SE activity and had significantly increased enzyme activity as compared to untreated peripheral blood mononuclear cells from healthy control subjects (p < 0.002), or interleukin-2-treated control cells (p < 0.05). A low percentage (0.4% +/- 0.2%) of cells in the graft-infiltrating lymphocyte cultures expressed the phenotypic marker NKH-1, suggesting that the source of BLT-SE in these cultures was not natural killer or lymphokine-activated T cells. Elevated BLT-SE was observed in five of ten cultures containing predominantly CD4+ cells and five of six cultures containing predominantly CD8+ T cells. Mixed phenotype graft-infiltrating lymphocyte cultures depleted of either CD4+ or CD8+ T cells retained BLT-SE activity. Thus both CD4+ and CD8+ graft-derived T cells can produce this enzyme although much greater variability in enzyme production was seen for CD4+ T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Pattern-reversal electroretinographic follow-up of laser photocoagulation for subfoveal neovascular lesions in age-related macular degeneration

Pattern-reversal electroretinograms were used as an objective measure of macular integrity in a subset of 42 patients who were randomly assigned at enrollment in the Macular Photocoagulation Study to receive laser photocoagulation or no treatment for a subfoveal neovascular lesion. Pattern-reversal electroretinograms were obtained before randomization, three months and six months after randomization, and at six-month intervals randomization, and at six-month intervals thereafter. Responses were obtained to phase-alternating checkerboards of varying check size. Extrapolation of the best-fit regression line relating log-check size to amplitude was used to determine retinal acuity. At each follow-up period, including three months after laser photocoagulation, treated eyes showed less loss in pattern-reversal electroretinographic acuity than untreated eyes. The decline in pattern-reversal electroretinographic acuity in untreated eyes corresponded to the rapid growth in the area of the subfoveal neovascular lesion. The more gradual decline in treated eyes was consistent with an increase in the area of the treatment scar caused by spreading atrophy.

Effect of cigarette smoking on coronary patency after thrombolytic therapy for myocardial infarction. TEAM-2 Investigators. Second Multicenter Thrombolytic Trials of Eminase in Acute Myocardial Infarction

Smokers have been reported to have an improved short-term prognosis after myocardial infarction when compared with nonsmokers. This study examines the effect of smoking status on infarct-related artery patency, a determinant of outcome, following thrombolytic therapy for acute myocardial infarction (AMI). To evaluate patency outcome by smoking status, the database of the Second Thrombolytic Trial of Eminase in Acute Myocardial Infarction was reviewed, and baseline characteristics were compared with infarct-related artery patency early (90 to 240 minutes) after thrombolysis in smokers versus nonsmokers. Smokers were younger (mean age 53 vs 59 years, p = 0.0001), more likely to be men (86 vs 73%, p = 0.008), normotensive (74 vs 58%, p = 0.004), to have an inferior infarction (66 vs 51%, p = 0.007), and tended to have higher hematocrits and fibrinogen levels than nonsmokers. Smokers had a significantly greater chance of achieving complete perfusion (Thrombolysis in Myocardial Infarction trial grade 3) (66 vs 51% p = 0.007) than nonsmokers, although the combination of grades 2 and 3 did not differ. After correcting for imbalances in baseline and angiographic variables, multivariate logistic regression identified smoking (odds ratio 1.8, p = 0.01) and infarct location (odds ratio 1.7, p = 0.03) as independent predictors of achieving grade 3 flow. The independent predictive component of smoking for achieving grade 3 patency after thrombolysis suggests the hypothesis that more active thrombogenic mechanisms may be operative in smokers, leading to a larger thrombus component that is more susceptible to lytic therapy.

Accelerated rejection of murine cardiac allografts by murine cytomegalovirus-infected recipients. Lack of haplotype specificity

Clinical studies have revealed a correlation between cytomegalovirus (CMV) infection and acute allograft rejection. Likewise, for a murine model we observed that C3H (H-2k) recipients infected with murine CMV (MCMV) rejected BALB/c (H-2d) cardiac allografts earlier than uninfected recipients (6.9 +/- 0.1 d compared with 8.1 +/- 0.6 d; P < 0.001). It has been hypothesized that MCMV epitopes crossreact with alloantigens and in this manner induce rejection. However, we also demonstrated that MCMV caused accelerated rejection in the reverse combination (C3H heart engrafted to BALB/c recipient; 7.2 +/- 0.3 and 9.4 +/- 0.4 d for infected and control animals, respectively; P < 0.001) and accelerated rejection of grafts of a third, unrelated haplotype (C57Bl/6; H-2b; 8.0 +/- 0.7 d compared with 10.1 +/- 0.6 for infected and control C3H recipients, respectively; P < 0.03). Ultraviolet (UV) inactivation of MCMV before administration to the graft recipient abrogated the ability to induce rapid rejection. Activated T lymphocytes were present in grafts from infected recipients 2 d before control recipients (P < 0.02) and, at the time of graft rejection, were almost exclusively CD8+ for both infected and control recipients. Thus, MCMV accelerated rejection appears not to result from crossreaction between MCMV epitopes and MHC products. The failure of UV-inactivated virus to accelerate rejection and the high proportion of CD8+ T cells recovered from all rejected grafts suggest that the class I pathway of antigen presentation may be important in the induction of early rejection.

TIMI perfusion grade 3 but not grade 2 results in improved outcome after thrombolysis for myocardial infarction. Ventriculographic, enzymatic, and electrocardiographic evidence from the TEAM-3 Study

BACKGROUND

Coronary patency has been used as a measure of thrombolysis success after acute myocardial infarction. The Thrombolysis in Myocardial Infarction (TIMI) Study Group perfusion grades have gained wide acceptance, with grades 0 (no distal flow) and 1 perfusion (minimal flow) being designated as thrombolysis failures and grades 2 (partial perfusion) and 3 (complete perfusion) as thrombolysis successes. However, the significance of the individual TIMI grades on clinical outcome has not been adequately assessed.

METHODS AND RESULTS

To evaluate the functional significance of TIMI perfusion grades, we compared 1-day coronary patency status with ventriculographic, enzymatic, and ECG indexes of acute myocardial infarction in 298 patients treated with anistreplase or alteplase within 4 hours of myocardial infarction symptom onset. Radionuclide ejection fraction was determined at 1 week and at 1 month. Perfusion grades for the entire study population were distributed as 12% (n = 37) grades 0/1, 13% (n = 40) grade 2, and 74% (n = 221) grade 3. Patency profile did not differ between the two thrombolytic regimens. Further coronary interventions were performed after the 1-day patency determination in 43% of patients (43%, 48%, 42%, respectively, in grades 0/1, 2, and 3 patients). The outcome of grade 2 patients did not differ from grades 0/1 patients in ejection fraction, enzyme peaks, ECG markers, or morbidity index. In contrast, grade 3 patients, compared with grades 0-2 patients, showed 1) a greater global ejection fraction at 1 week (54% versus 49%, p = 0.006) and at 1 month (54% versus 49%, p = 0.01), 2) a greater infarct zone ejection fraction at 1 week (41% versus 33%, p = 0.003) and at 1 month (42% versus 32%, p = 0.003), 3) smaller enzyme peaks, significant for lactate dehydrogenase, and shorter times to enzyme peaks, significant for all four enzymes, 4) a smaller QRS score at discharge and at 1 month, and 5) a trend toward a lower morbidity index.

CONCLUSIONS

Grade 3 flow predicts significantly better outcomes than lesser grades of flow and represents an important measure of reperfusion success.

Antiarrhythmic and pharmacokinetic evaluation of intravenous recainam in patients with frequent ventricular premature complexes and unsustained ventricular tachycardia

The pharmacokinetics, antiarrhythmic activity and safety of intravenously administered recainam were evaluated in 15 men and 3 women. All patients had frequent (> 30/hour) ventricular premature complexes (VPCs) and unsustained ventricular tachycardia. Recainam was administered at a loading dose of 4.5 mg/kg/hour over 40 minutes, followed by a maintenance infusion of 0.9 mg/kg/hour for 23 hours and 20 minutes. Sixteen patients had satisfactory efficacy data. The mean frequency of total VPCs decreased by 92.6% and the mean frequency of runs decreased by 99.9% during the maintenance infusion. Suppressions of > or = 70% of total VPCs and > or = 90% of runs were maintained over the 23-hour, 20-minute maintenance infusion period in 16 of the 18 patients. During the maintenance infusion, hourly group plasma recainam concentrations ranged from mean +/- SD 2.6 +/- 0.7 to 3.4 +/- 0.9 micrograms/ml. Patients were observed for 24 hours after termination of the infusion. Periodic blood samples were obtained during and after termination of the infusion to determine recainam concentration. Urine specimens were collected over scheduled intervals to determine urinary excretion of recainam. A 2-compartment pharmacokinetic model was used to analyze the data. The following pharmacokinetic parameters were obtained: terminal elimination half-life, 5.0 +/- 0.8 hours; systemic clearance, 0.27 +/- 0.08 liter/hour/kg; and central and steady-state volume of distribution, 0.32 +/- 0.11 and 1.4 +/- 0.4 liter/kg, respectively. Adverse experiences were reported in 4 of the 18 patients, possibly drug-related in 2; none was considered severe or required discontinuation of recainam.(ABSTRACT TRUNCATED AT 250 WORDS)

An overview of the patency and stroke rates following thrombolysis with streptokinase, alteplase, and anistreplase used to treat an acute myocardial infarction

The results of an overview of early (90-240 min) and late (24 hours or more) patency and of stroke rates for each of the three commercially available thrombolytic agents, streptokinase, alteplase, and anistreplase are presented. Studies included in this analysis are all those published between 1985 and March 1992 and focus on the licensed dosage regimens of each agent. The rates of early and late patency for streptokinase were 64.7% and 80.8%; for alteplase, 66.6% and 73.7%; and for anistreplase, 72.1% and 84.5%. The rates of total and hemorrhagic stroke for streptokinase were 0.69% and 0.17%; for alteplase, 1.27% and 0.50%; and for anistreplase 0.91% and 0.38%. These results provided evidence that the rates of early and late patency appeared to be greatest for anistreplase and that the rates of stroke are within "acceptable" ranges for all three thrombolytic agents with streptokinase affording the lowest rate.

Mechanism of benefit of combination thrombolytic therapy for acute myocardial infarction: a quantitative angiographic and hematologic study

OBJECTIVES

The goal of this study was to lend insight into the mechanisms responsible for the beneficial effects of combination thrombolytic therapy.

BACKGROUND

Combination thrombolytic therapy for acute myocardial infarction has been associated with less reocclusion and fewer in-hospital clinical events than has monotherapy.

METHODS

Infarct-related quantitative coronary dimensions and hemostatic protein levels were evaluated in 287 patients with acute myocardial infarction during the early (90-min) and convalescent (7-day) phases after administration of recombinant tissue-type plasminogen activator (rt-PA), urokinase or combination rt-PA and urokinase.

RESULTS

Minimal lumen diameter was similar in the 90-min and 7-day phases after treatment with rt-PA, urokinase and combination rt-PA and urokinase (0.72 +/- 0.45 mm, 0.62 +/- 0.53 mm and 0.75 +/- 0.58 mm, respectively, at 90 min, p = 0.16; and 1.05 +/- 0.56 mm, 1.12 +/- 0.72 mm and 0.94 +/- 0.54 mm, respectively, at 7 days, p = 0.22). In-hospital clinical event and reocclusion rates were less frequent in patients receiving combination therapy than in those receiving monotherapy (25% vs. 38% and 32% for rt-PA and urokinase, respectively, p = 0.084; and 3% vs. 13% and 9% for rt-PA and urokinase, respectively, p = 0.03), but these events were unrelated to early or late coronary dimensions. Patients receiving combination therapy or urokinase monotherapy had significantly higher peak fibrin degradation products (1,307 +/- 860 and 1,285 +/- 898 micrograms/ml vs. 435 +/- 717 micrograms/ml, respectively, p < 0.0001) and lower nadir fibrinogen levels (0.85 +/- 1.00 and 0.75 +/- 0.53 g/liter vs. 1.90 +/- 0.86 g/liter, respectively, p < 0.0001) than did those receiving rt-PA monotherapy. Peak fibrinogen degradation products indirectly correlated (p = 0.004) and baseline (p = 0.026) and nadir (p = 0.089) fibrinogen levels directly correlated with reocclusion.

CONCLUSIONS

Lower in-hospital clinical event and reocclusion rates observed with combination thrombolytic therapy may relate to systemic hematologic factors rather than to the residual lumen obstruction after thrombolysis.

Standardized full-field electroretinography. Normal values and their variation with age

Full-field electroretinograms were obtained in 269 normal subjects with the International Standardization Protocol endorsed by the International Society for Clinical Electrophysiology of Vision and the National Retinitis Pigmentosa Foundation Inc. Log rod and cone amplitudes decreased exponentially with age in adults; amplitudes declined to one half those in the young adult level (ages 15 to 24 years) by ages 69 and 70 years for rod and cone responses, respectively. B-wave implicit times increased with age for all responses. Lower limits of normal peak-to-peak amplitude and upper limits of normal b-wave implicit time (P < .05) were determined for each decade from birth to age 79 years. Naka-Rushton functions relating rod peak-to-peak amplitude to retinal illuminance were determined in 50 normal subjects. A significant decline in the log maximum asymptotic amplitude with age accounted for most of the amplitude decline in the standard protocol rod response. The average value of log k, the semisaturation constant, was only 0.1 log unit higher at age 70 years than at age 20 years, consistent with previous studies showing little decrease in photopigment optical density with age.

Changes in norepinephrine output following light therapy for fall/winter seasonal depression

Recurrent fall/winter depressions that remit during spring and summer have been called Seasonal Affective Disorders (SAD) (Wehr and Rosenthal 1989). The pathophysiology of SAD, its relationship to nonseasonal affective disorders, and the mechanism of action of light therapy, which is effective in treating SAD, remain to be elucidated (Depue et al 1989; Jacobsen et al 1987; James et al 1986; Joseph-Vanderpool et al 1991; Skwerer et al 1988, Terman et al 1989). Norepinephrine (NE) may play a role in the mechanisms of action of many antidepressant treatments (Schildkraut 1965) that alter NE metabolism (Schildkraut et al 1964 and 1965) and decrease the urinary output of NE and its metabolites, i.e., "whole-body NE turnover" (WBNET) (Golden et al 1988; Potter et al 1988). The present study explored whether light therapy also reduces the urinary output of NE and its metabolites.

Anistreplase versus alteplase in acute myocardial infarction: comparative effects on left ventricular function, morbidity and 1-day coronary artery patency. The TEAM-3 Investigators

OBJECTIVES

This double-blind, randomized, multicenter trial was designed to compare the effects of treatment with anistreplase (APSAC) and alteplase (rt-PA) on convalescent left ventricular function, morbidity and coronary artery patency at 1 day in patients with acute myocardial infarction.

BACKGROUND

Anistreplase (APSAC) is a new, easily administered thrombolytic agent recently approved for treatment of acute myocardial infarction. Alteplase (rt-PA) is a rapidly acting, relatively fibrin-specific thrombolytic agent that is currently the most widely used agent in the United States.

METHODS

Study entry requirements were age less than or equal to 75 years, symptom duration less than or equal to 4 h, ST segment elevation and no contraindications. The two study drugs, APSAC, 30 U/2 to 5 min, and rt-PA, 100 mg/3 h, were each given with aspirin (160 mg/day) and intravenous heparin. Prespecified end points were convalescent left ventricular function (rest/exercise), clinical morbidity and coronary artery patency at 1 day. A total of 325 patients were entered, stratified into groups with anterior (37%) or inferior or other (63%) acute myocardial infarction, randomized to receive APSAC or rt-PA and followed up for 1 month.

RESULTS

At entry, patient characteristics in the two groups were balanced. Convalescent ejection fraction at the predischarge study averaged 51.3% in the APSAC group and 54.2% in the rt-PA group (p less than 0.05); at 1 month, ejection fraction averaged 50.2% versus 54.8%, respectively (p less than 0.01). In contrast, ejection fraction showed similar augmentation with exercise at 1 month after APSAC (+4.3% points) and rt-PA (+4.6% points), and exercise times were comparable. Coronary artery patency at 1 day was high and similar in both groups (APSAC 89%, rt-PA 86%). Mortality (APSAC 6.2%, rt-PA 7.9%) and the incidence of other serious clinical events, including stroke, ventricular tachycardia, ventricular fibrillation, heart failure within 1 month, recurrent ischemia and reinfarction were comparable in the two groups; and mechanical interventions were applied with equal frequency. A combined clinical morbidity index was determined and showed a comparable overall outcome for the two treatments.

CONCLUSIONS

Convalescent rest ejection fraction was high after both therapies but higher after rt-PA; other clinical outcomes, including exercise function, morbidity index, and 1-day coronary artery patency, were favorable and comparable after APSAC and rt-PA.

Inhibition of benzo[a]pyrene-induced bone marrow micronuclei formation by diallyl thioethers in mice

Diallyl thioethers (DATEs), naturally occurring compounds present in garlic, were investigated for their putative ability to inhibit benzo[a]pyrene-induced genotoxicity in ICR and C3H strains of mice. The mouse bone marrow micronucleus assay was used as an indicator of in vivo genotoxicity. A dose of 0.67 mmol total DATEs/kg body weight inhibited formation of micronucleated polychromatic erythrocytes (MPCEs) by 24%, and 0.33 mmol DATEs inhibited formation of MPCEs by 45%. Possibly the toxicity of DATEs accounted for less inhibition with the higher dose. Formation of MPCEs were inhibited only slightly by DATEs in C3H mice. These results indicate that the mouse bone marrow micronucleus assay can be used to identify organosulfur components of garlic that inhibit genotoxicity.