When Public Health Becomes Politicized

Perhaps nothing symbolizes the current polarized political climate in the United States more than the world of public health. Public health schools and health departments are full of “true believers,” people willing to crusade for any program designed to reduce morbidity and mortality. But in the “real world,” proven programs and strategies—such as gun‐control measures, universal vaccination, and improved traffic safety—are routinely thwarted. Why do critics oppose efforts to improve the public's health? History can provide some answers.      

Postextrasystolic U Wave Augmentation, a New Marker of Increased Arrhythmic Risk in Patients Without the Long QT Syndrome

Objectives. We attempted to determine the correlation between the presence of postextrasystolic changes in the STU segment and a history of sustained ventricular arrhythmias.

Background. Postextrasystolic U wave augmentation (a marked increment in U wave amplitude after premature ventricular complexes [PVCs]) is an adverse prognostic sign in the “pause-dependent long QT syndrome.” However, the prevalence of postextrasystolic changes in patients without the long QT syndrome is unknown.

Methods. We compared the configuration of the STU segment of the postextrasystolic beat (the sinus beat after a PVC) with the STU configuration during sinus rhythm in three patient groups: 1) 41 patients with spontaneous ventricular tachycardia/fibrillation (VT/VF) (VT/VF group), 2) 63 patients with heart disease and high grade ventricular arrhythmias (control group), and 3) 29 patients with high grade ventricular arrhythmias but no heart disease (reference group).

Results. Postextrasystolic T wave changes did not correlate with a history of ventricular tachyarrhythmias. However, postextrasystolic U wave changes were more common among the patients with VT/VF than among control subjects (39% vs. 8.7%, p < 0.001). By logistic multiple regression analysis, a low left ventricular ejection fraction (p < 0.001) and postextrasystolic U wave changes (p < 0.005) were independent predictors of ventricular tachyarrhythmias.

Conclusions. Postextrasystolic T wave changes are common and lack predictive value. Postextrasystolic U wave changes may be a specific marker of a tendency to the development of spontaneous ventricular arrhythmias. Prospective studies should be performed to confirm this association.

(J Am Coll Cardiol 1996;28:1746–52)>     

Fluidity theory and neuropsychological impairment in alcoholism.

In order to determine whether the "classic" alcoholic WAIS pattern is the result of right hemisphere damage or the loss of fluid intelligence abilities, right-hemisphere damaged, left-hemisphere damaged, alcoholic, and control groups of 40 subjects each were matched on the variables of age and education. They were administered the WAIS-Revised (WAIS-R) and four sensory and motor measures that were sensitive to lateralized damage but not to fluidity. The alcoholic group showed the "classic" pattern of a lower performance than verbal WAIS IQ. Although the left hand scores on the sensory and motor tests were significantly more impaired than the right hand scores for the right-hemisphere damaged group they were not for the alcoholic group. These results did not support the right hemisphere theory. Rather, as indicated by further analysis, the pattern is most adequately explained by the fluidity theory.     

The influence of vagal afferents on the left ventricular contractile response to intracoronary administration of catecholamines in the conscious dog

We studied the effect of vagal afferents on the left ventricular contractile response (LVdP/dtmax) to administration of sympathomimetic amines into the left circumflex coronary artery in conscious dogs. The positive inotropic effects of bolus administration of epinephrine, norepinephrine, and isoproterenol were greater during bilateral vagal cold block (BVB) that in the control state with the vagi intact (P less than 0.001). The inotropic potentiation observed with BVB was not due to vagal efferent interruption, since parasympathetic efferent block with atropine did not potentiate the inotropic effects of intracoronary epinephrine (P greater than 0.05). BVB also potentiated the inotropic effects of constant intracoronary infusion of epinephrine (P less than 0.01). BVB alone had no significant effect on LVdP/dtmax; dtmax (P less than 0.05). We propose that the potentiation of the inotropic effects during BVB could result from either interruption of a vagal afferent-mediated negative feedback reflex and/or an unmasking of a sympathetic afferent-mediated positive feedback effect induced by BVB. However, the observations that ganglionic blockade also potentiated the contractile effects of epinephrine supports the concept that a negative feedback reflex does attenuate the inotropic effect of catecholamines in the control state. In conclusion, these data suggest that vagal afferents attenuate the positive inotropic effects of intracoronary administration of catecholamines via a cardiocardiac negative feedback reflex which occurs through a vagal afferent inhibition of sympathetic efferent activity back to the left ventricle.     

Mitochondrial abnormalities in ageing macular photoreceptors.

PURPOSE: To evaluate somatic mitochondrial (mt)DNA mutations in the macula during ageing. METHODS: Ten 30-microm cryostat sections from the macula (foveal and perifoveal regions) and peripheral retina of 14 donors (aged 14-94 years) were cut for cytochrome c oxidase cytochemistry. The photoreceptor layer was microdissected and DNA extracted for 4977-bp mtDNA (mtDNA(4977)) quantification using PCR. Dual cytochemistry for cytochrome c oxidase and succinate dehydrogenase allowed the detection of cytochrome c oxidase-deficient cones. RESULTS: Findings showed a progressive accumulation of mtDNA(4977) from ages 14 to 94 years. From ages 14 to 60 years there was an increase from 0.006% to 0.25%, and from ages 60 to 94 years there was a steeper increase from 0.25% to 5.39%. Counts of cones in the dual-reacted preparations showed more cytochrome c oxidase-deficient cones in the foveal region than elsewhere. CONCLUSIONS: The results show that mitochondrial DNA deletions and cytochrome c oxidase-deficient cones accumulate in the ageing retina, particularly in the foveal region. These defects may contribute to the changes in macular function observed in ageing and age-related maculopathy.     

Treatment and outcomes of left bundle-branch block patients with myocardial infarction who present without chest pain. National Registry of Myocardial Infarction 2 Investigators

OBJECTIVES: We sought to determine the importance of chest pain on presentation as a predictor of in-hospital treatment and mortality in myocardial infarction (MI) patients with left bundle-branch block (LBBB). BACKGROUND: Left bundle-branch block patients have a high mortality after MI but are unlikely to receive reperfusion therapy despite evidence from clinical trials demonstrating the efficacy of thrombolytic therapy. Nearly half of MI patients with LBBB present without chest pain. METHODS: We studied the clinical features, treatment and in-hospital survival of 29,585 patients with LBBB enrolled in the National Registry of MI 2 June 1994 through March 1998). Multivariate logistic regression was used to assess the independent effect of chest pain on reperfusion decisions and in-hospital mortality. RESULTS: Left bundle-branch block patients with chest pain were greater than five-fold more likely to receive reperfusion therapy (13.6% vs. 2.6%) than LBBB patients without chest pain; they were also more likely to receive aspirin, beta-adrenergic blocking agents, heparin and nitrates (all p < 0.0001). Unadjusted in-hospital mortality was 18% in patients with chest pain and 27% in patients without chest pain. Adjusting for patient characteristics reduced the odds ratio associated with the absence of chest pain from 1.47 (95% confidence interval: 1.41 to 1.54) to 1.21 (95% confidence interval: 1.12 to 1.30). The remainder of the mortality difference was caused by the undertreatment of patients without chest pain, particularly the low utilization of aspirin and beta-blockers. CONCLUSIONS: Left bundle-branch block patients with MI who present without chest pain are less likely to receive optimal therapy and are at increased risk of death. Prompt recognition and treatment of this high-risk subgroup should improve survival.     

Isolation and culture of rat retinal microvessel endothelial cells using magnetic beads coated with antibodies to PECAM-1

PURPOSE. To isolate retinal endothelial cells (RECs) from Lewis rats using magnetic beads coated with antibodies to rat platelet-endothelial cell adhesion molecule-1 (PECAM-1) and to characterize the cultured RECs. METHODS. Magnetic beads were coated with anti-rat PECAM-1 antibodies. Retinas were obtained from Lewis rat eyes. After the retinas were digested with collagenase, they were incubated with the antibody-coated beads with agitation. RECs that stuck to the beads were collected with a magnetic particle concentrator and cultured in fibronectin coated wells. The characteristics of the RECs were examined by immunohistochemical study utilizing von Willebrand's Factor, acetylated low-density lipoprotein uptake and transmission electron microscopy. RESULTS. The cells isolated using the PECAM-1-coated magnetic-bead technique formed a contact-inhibited cobblestone monolayer that stained positive for von Willebrand's Factor. These cells revealed low-density lipoprotein uptake. Ultrastructurally, the isolated cells exhibited pinocytic vesicles and a high density of intercellular junctions without fenestrations. CONCLUSION. These results indicate that the isolated cells were vascular endothelial cells showing both morphologic and functional characteristics of retinal vascular endothelium. The magnetic-bead technique was useful for isolating high purity RECs that can be cultured to study the physiological, immunological and biochemical role of the endothelium in various ocular diseases.     

Prevalence of glaucoma in a rural East African population

PURPOSE: To determine the prevalence of glaucoma in an adult population in rural central Tanzania. METHODS: Six villages were randomly selected from eligible villages in the Kongwa district, and all residents more than 40 years of age were enumerated and invited to a comprehensive eye examination including presenting visual acuity, refraction, automated 40-point Dicon (San Diego, CA) suprathreshold screening field test, Tono-Pen (Bio-Rad, Inc., Boston, MA) intraocular pressure (IOP) measurement, and standardized examination by an ophthalmologist of anterior segment, optic nerve head, and retina after pupil dilation. Gonioscopy and Glaucoma-Scope (Ophthalmic Imaging Systems, Sacramento, CA) optic disc imaging were performed on those with IOP higher than 23 mm Hg and cup-to-disc ratio (c/d) more than 0.6 and on a 20% random sample of participants. RESULTS: Of 3641 eligible persons, 3268 (90%) underwent ophthalmic examination. The prevalence of glaucoma of all types was 4.16% (95% confidence interval [CI] = 3.5, 4.9%). Primary open-angle glaucoma (OAG) was diagnosed in 3.1% (95% CI = 2.5, 3.8%), primary angle-closure glaucoma (ACG) in 0.59% (95% CI = 0.35, 0.91%), and other forms of glaucoma in 0.49%. The prevalence of glaucoma was found to be sensitive to changes in the diagnostic criteria. CONCLUSIONS: The high prevalence of OAG in this group was similar to that of African-derived persons in the United States but less than in African-Caribbean populations. ACG was more prevalent in east Africans than suggested by anecdotal reports.