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At least 1,207 records · Page 67Linked to original sources
PubMed1999

Species-dependent variation in the dendritic stratification of apparently homologous retinal ganglion cell mosaics in two neoteleost fishes.

Large retinal ganglion cells of the marine neoteleost Bathymaster derjugini were labeled with horseradish peroxidase and studied in flatmounts. Four types formed regular, independent mosaics, of which three (biplexiform, alpha-a, alpha-c) resembled those in several other teleosts. The fourth (alpha-ab) appeared novel in one significant respect. Whereas we originally described similar cells in another neoteleost, Oreochromis spilurus, as monostratified in sublamina b of the inner plexiform layer, these were very clearly bistratified in a and b. Detailed re-analysis of our Oreochromis flatmounts showed that the difference is of one degree only: many Oreochromis cells do send fine dendrites into a. These observations strengthen the evidence that all four mosaics are homologous across a wide range of fishes, and clear away an obstacle to our earlier proposals that the alpha-a, alpha-ab and alpha-c mosaics of fishes, frogs, and perhaps other nonmammalian jawed vertebrates too, may all be homologous.

Animals↗
PubMed2001

Prostate-specific antigen-enhanced testing and risk stratification for chemoprevention trials.

Prostate-specific antigen (PSA) testing could be used to identify men who are at higher future risk of developing clinical prostate cancer or to diagnose prostate cancer earlier in high-risk groups, such as black men or those with a family history of the disease. These cohorts then could be offered chemopreventive clinical trial participation opportunities. The Physicians' Health Study and other longitudinal studies have shown that even between a PSA level of 1.0 and 4.0 ng/mL, the risk of future prostate cancer is incrementally increased. Department of Defense Studies of young men between 15 and 45 show that normal men have very low PSA values. Using a threshold PSA even as low as 1.5 ng/mL for men in their fifth decade is well beyond the 95th percentile of "normal" PSA. Young black men between 40 and 49 years old have a higher risk of prostate cancer than white men and should be pursued for chemoprevention studies. PSA is not perfect. Benign prostatic hyperplasia and inflammation (and, perhaps, other factors) can confound the use of PSA thresholds to identify men for chemoprevention or early detection. Certain chemopreventive agents may affect PSA physiology without affecting the disease process itself creating a meaningless epiphenomenon. Young black men may not generally be receptive to PSA testing or chemopreventive trials.

Adult↗
PubMed1999

Troponin concentrations for stratification of patients with acute coronary syndromes in relation to therapeutic efficacy of tirofiban. PRISM Study Investigators. Platelet Receptor Inhibition in Ischemic Syndrome Management.

BACKGROUND: A major challenge for physicians is to identify patients with acute coronary syndromes who may benefit from treatment with glycoprotein-IIb/IIIa-receptor antagonists. We investigated whether troponin concentrations can be used to stratify patients for benefit from treatment with tirofiban. METHODS: We enrolled 2222 patients of the Platelet Receptor Inhibition in Ischemic Syndrome Management study with coronary artery disease and who had had chest pain in the previous 24 h. All patients received aspirin and were randomly assigned treatment with tirofiban or heparin. We took baseline measurements of troponin I and troponin T. We recorded death, myocardial infarction, or recurrent ischaemia after 48 h infusion treatment and at 7 days and 30 days. FINDINGS: 629 (28.3%) patients had troponin I concentrations higher than the diagnostic threshold of 1.0 microg/L and 644 (29.0%) troponin T concentrations higher than 0.1 microg/L. 30-day event rates (death, myocardial infarction) were 13.0% for troponin-I-positive patients compared with 4.9% for troponin-I-negative patients (p<0.0001), and 13.7% compared wth 3.5% for troponin T (p<0.001). At 30 days, in troponin-I-positive patients, tirofiban had lowered the risk of death (adjusted hazard ratio 0.25 [95% CI 0.09-0.68], p=0.004) and myocardial infarction (0.37 [0.16-0.84], p=0.01). This benefit was seen in medically managed patients (0.30 [0.10-0.84], p=0.004) and those undergoing revascularisation (0.37 [0.15-0.93] p=0.02) after 48 h infusion treatment. By contrast, no treatment effect was seen for troponin-I-negative patients. Similar benefits were seen for troponin-T-positive patients. INTERPRETATION: Troponin I and troponin T reliably identified high-risk patients with acute coronary syndromes, managed medically and by revascularisation, who would benefit from tirofiban.

Aged↗
PubMed2004

Risk stratification and survival in post myocardial infarction patients: a large prospective and multicenter study in Japan.

BACKGROUND: Recent clinical trials suggest that the mortality in high-risk patients with ischemic heart disease can be significantly reduced with the use of implantable cardioverter-defibrillator (ICD). Given the high cost and invasiveness of the procedure, it is important to apply it to the patients after myocardial infarction (MI) highly susceptible to sudden arrhythmic death. OBJECTIVE: The purpose of this study was to assess clinical predictors of mortality in post-MI patients in Japan. METHODS AND RESULTS: In 495 consecutive MI survivors, 350 (71%) received acute-reperfusion therapy, whereas 145 (29%) did not. Nonsustained ventricular tachycardia (NSVT) was present in 136 patients (28%) in 24-h ambulatory ECGs at 7+/-6 in-hospital days. Left ventricular dysfunction (LVEF< or =35%) was present in 20/347 patients (5.7%) at 13+/-8 days. Forty-eight patients (9.7%) died during the follow-up period (48+/-13 months); 23 from cardiac and 25 from noncardiac causes. Kaplan-Meier survival analyses showed that mortality rates were higher among patients who were > or =70 years old (log-rank test, P<0.0001); had heart failure at admission (Killip scale> or =2, P=0.001); did not receive acute-reperfusion (P=0.004); and had left ventricular dysfunction with LVEF< or =35% (P=0.02). The presence of NSVT was a significant predictor of death (P=0.036) only in the patients who did not receive acute-reperfusion. Multivariate Cox regression analysis revealed that an independent predictor of total mortality was an age> or =70 (odds ratio, 1.06; 95% confidence interval, 1.01-1.11; P<0.00001). CONCLUSIONS: High-risk patients after acute MI can be identified on the basis of age, ventricular dysfunction, heart failure and acute-reperfusion therapy. The presence of NSVT before discharge has a prognostic value only in the patients without acute-reperfusion.

Aged↗
PubMed1999

Risk stratification of sudden cardiac death and malignant ventricular arrhythmias in right ventricular dysplasia-cardiomyopathy.

UNLABELLED: Arrhythmogenic right ventricular dysplasia-cardiomyopathy is in most cases a benign cause of ventricular arrhythmias in young patients. The major reason of mortality is sudden arrhythmic death with an annual rate of 2-3% as the first manifestation of the disease in most cases. Little is known about risk factors of sudden arrhythmic death so far. The purpose of the retrospective study was to classify risk factors from invasive and non-invasive examinations. METHODS: In a cohort of 121 consecutive patients sampled from 1986 to 1998 the value of right ventricular dilatation, left ventricular involvement analysed by angiocardiography or echocardiography and standard ECG parameters such as precordial T wave inversions, right precordial ST elevation, precordial QRS dispersion, left precordial JT interval prolongation and complete right bundle branch block were determined. The whole cohort of patients were divided into two groups with high arrhythmic risk (aborted or non-aborted sudden death, recurrent ventricular tachycardia despite medical treatment, recurrent syncopes) and low risk (frequent ventricular premature beats, non sustained ventricular tachycardia, uneventful course under medical therapy). RESULTS: From angiocardiography or echocardiography in a quantitative approach right ventricular dilatation (p<0.0001) and additional left ventricular abnormalities (p<0.0001) could be identified as major risk factors. From an ECG point of view increased precordial QRS dispersion > or =50 ms (p<0.01) with complete right bundle branch block and right ventricular dilatation in most cases and precordial T wave inversions beyond V3 (p<0.0001) and the phenomenon of left precordial JT interval prolongation (JT dispersion > or =30 ms) in cases of additional left ventricular abnormalities represented non-invasive predictors of recurrent arrhythmic events. Right precordial ST segment elevation could be excluded as risk factor of sudden arrhythmic death. CONCLUSIONS: Right ventricular dilatation with ECG depolarisation abnormalities and additional left ventricular involvement with striking ECG repolarisation abnormalities could be identified as strong risk factors of recurrent arrhythmic events in ARVD with unfavorable prognosis.

Adult↗
PubMed2003

Role of cardiac troponin T in the long-term risk stratification of patients undergoing percutaneous coronary intervention.

AIMS: To investigate the long-term prognostic significance of pre- and post-procedure troponin T (TnT) elevations in patients undergoing percutaneous coronary intervention (PCI). METHODS AND RESULTS: TnT and CK-MB were measured pre- and post-procedure in 212 patients undergoing PCI. Major adverse events (composite of death, myocardial infarction and revascularization) were ascertained 6 years later. Pre-procedural TnT was a significant independent predictor of time to major events (hazard ratio [HR] 1.75, 95% confidence interval [CI] 1.16-2.64) and death or myocardial infarction. Post-procedural TnT elevation above normal was the only independent predictor of the primary end-point at 1 year (HR 2.39, 95% CI 1.09-5.26) but was not significantly related to event-free survival throughout follow-up. Post-PCI elevation of TnT 5x above normal, however, did significantly predict time to events during the entirety of follow-up. By contrast, CK-MB was not an independent predictor in any of the analyses. CONCLUSIONS: Our study confirms the long-term prognostic value of pre-procedural TnT elevation in patients undergoing PCI, and demonstrates the superior predictive ability of a post-procedural increase in TnT 5x normal for long-term adverse events. Whether the prognostic significance of smaller post-procedural TnT elevations extends beyond the intermediate-term awaits further investigation.

Adult↗
PubMed2003

High prevalence of right ventricular involvement in endurance athletes with ventricular arrhythmias. Role of an electrophysiologic study in risk stratification.

BACKGROUND: Electrocardiographic abnormalities and premature ventricular contractions are common in athletes and are generally benign. However, the specific outcome of high-level endurance athletes with frequent and complex ventricular arrhythmias is unclear. Also, information on the predictive accuracy of different investigations in this subgroup is unknown. RESULTS: We report on 46 high-level endurance athletes with ventricular arrhythmias (45 male; median age 31 years) followed-up for a median of 4.7 years. Eighty percent were cyclists. Hypertrophic cardiomyopathy or coronary abnormalities were present in < or =5%. Eighty percent of the arrhythmias had a left bundle branch morphology. Right ventricular (RV) arrhythmogenic involvement (based on a combination of multiple criteria) was manifest in 59% of the athletes, and suggestive in another 30%. Eighteen athletes developed a major arrhythmic event (sudden death in nine, all cyclists). They were significantly younger than those without event (median 23 years vs 38 years; P=0.01). Outcome could not be predicted by presenting symptoms, non-invasive arrhythmia evaluation or morphological findings at baseline. Only the induction of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) during invasive electrophysiological testing was significantly related to outcome (RR 3.4; P=0.02). Focal arrhythmias were associated with a better prognosis than those due to reentry (P=0.02) but the mechanism could be determined in only 22 (48%). CONCLUSIONS: Complex ventricular arrhythmias do not necessarily represent a benign finding in endurance athletes. An electrophysiological study is indicated for risk evaluation, both by defining inducibility and identifying the arrhythmogenic mechanism. Endurance athletes with arrhythmias have a high prevalence of right ventricular structural and/or arrhythmic involvement. Endurance sports seems to be related to the development and/or progression of the underlying arrhythmogenic substrate.

Adolescent↗