Search

Broadcast spawning corals release gametes into the oceans with extraordinarily accurate timing. While the date of spawning is set by the lunar cycle, the hour/minute of spawning is set by the solar cycle. In this report, we describe experiments that test whether the time of spawning is regulated by an entrained biological clock or whether it is directly controlled by the solar cycle. Montastraea franksi samples were collected on the morning of the predicted spawning. Fragments from colonies were kept under three different lighting conditions and spawning monitored. The three conditions were sunset times of 0, 1 or 2 h earlier than normal. Fragments from the same colony spawned differently under these three conditions, with an early sunset causing a corresponding early shift in spawning. These results indicate that spawn timing is not controlled by a circadian rhythm and that it is directly controlled by local solar light cycle.

The demonstration that angiogenic growth factors can stimulate new blood vessel growth and restore perfusion in animal models of myocardial ischemia has led to the development of strategies designed for the local production of angiogenic growth factors in patients who are not candidates for conventional revascularization. The results of recent clinical trials of proangiogenesis gene therapy have been disappointing; however, significant limitations in experimental design, in particular in gene transfer strategies, preclude drawing definitive conclusions. In the REVASC study cardiac gene transfer was optimized by direct intramyocardial delivery of a replication-deficient adenovirus-containing vascular endothelial growth factor (AdVEGF121, 4 x 10(10) particle units (p.u.)). Sixty-seven patients with severe angina due to coronary artery disease and no conventional options for revascularization were randomized to AdVEGF121 gene transfer via mini-thoracotomy or continuation of maximal medical treatment. Exercise time to 1 mm ST-segment depression, the predefined primary end-point analysis, was significantly increased in the AdVEGF121 group compared to control at 26 weeks (P=0.026), but not at 12 weeks. As well, total exercise duration and time to moderate angina at weeks 12 and 26, and in angina symptoms as measured by the Canadian Cardiovascular Society Angina Class and Seattle Angina Questionnaire were all improved by VEGF gene transfer (all P-values at 12 and 26 weeks < or =0.001). However, if anything the results of nuclear perfusion imaging favored the control group, although the AdVEGF121 group achieved higher workloads. Overall there was no significant difference in adverse events between the two groups, despite the fact that procedure-related events were seen only in the thoracotomy group. Therefore, administration of AdVEGF121 by direct intramyocardial injections resulted in objective improvement in exercise-induced ischemia in patients with refractory ischemic heart disease.

Quaintitative, single voxel proton nuclear magnetic resonance (NMR) spectroscopy and histological analysis was performed in eight dogs implanted with the transplantable canine glioma model of Wodinsky (Proc. Am. Assoc. Cancer Res. 10, 99 (1969). Signals from choline, creatine, N-Acetyl Aspartate (NAA) and lactate were converted to molar concentration units and correlated with the quantitative analysis of histologically determined tissue types within the localized volume selected for NMR spectroscopy. In general, compared with normal brain, the lesions were associated with reductions in all metabolite concentrations, with the exception of lactate, which was increased. NAA and creatine decreases were most significantly correlated with the total lesion volume (P < 0.01), suggesting that these compounds are present in normal brain only. Changes in choline levels did not correlate strongly with any particular tissue type. Lactate was found to increase with increasing total lesion volume (P < 0.01), but not with increasing percent tumor, suggesting that it accumulates in abnormal tissue other than the tumor. The spectra reported were similar to those observed in human glioblastomas, with the exception that elevations of choline were not observed. The transplant-able canine gliosarcoma system appears to be a suitable tumor model for evaluation by clinical radiological techniques such as magnetic resonance imaging (MRI) and proton NMR spectroscopy.

Background: Bleeding and transfusion after percutaneous coronary intervention (PCI) are known predictors of mortality. Transradial arterial access reduces bleeding and transfusion related to femoral access complications, although its association with mortality is unknown. Objective: To determine the association of arterial access site (radial or femoral) with transfusion and mortality in unselected PCIs. Design, setting and patients: By data linkage of three prospectively collated provincial registries, 38 872 procedures in 32 822 patients in British Columbia were analysed. The association between access site, transfusion and outcomes was assessed by logistic regression, propensity score matching and probit regression. Main outcome measures: 30-Day and 1-year mortality. Results: 1134 (3.5%) patients had at least one blood transfusion. Transfused patients had a significantly increased 30-day and 1-year mortality, adjusted odds ratio (95% CI) 4.01 (3.08 to 5.22) and 3.58 (2.94 to 4.36), respectively. By probit regression the absolute increase in risk of death at 1 year associated with receiving a transfusion was 6.78%. The number needed to treat was 14.74 (prevention of 15 transfusions required to “avoid” one death). Radial access halved the transfusion rate. After adjustment for all variables, radial access was associated with a significant reduction in 30-day and 1-year mortality, odds ratio = 0.71 (95% CI 0.61 to 0.82) and 0.83 (0.71 to 0.98), respectively (all p Conclusions: In a registry of all comers to PCI, transradial access was associated with a halving of the transfusion rate and a reduction in 30-day and 1-year mortality.

There is limited data on patient preference for same-day discharge PCI. We contacted 953 patients who had same-day discharge radial PCI between 1998 and 2001 and checked whether they were satisfied with same-day discharge and whether they had any complications within 30 days post-PCI (vascular, repeat angiogram/PCI). Complications and health status were also verified by checking hospital records, our province-wide cath lab database and provincial vital statistics, as well as by contacting the referring doctor. A total of 811 patients responded. Of this total, 88.6% of the patients were satisfied with same-day discharge PCI, and 11.4% were not. Patients were significantly more satisfied with same-day discharge when they did not experience vascular complications (83.4% versus 91.5% satisfied with and without vascular complications at 24 hours, and 74.3% versus 90.9% at 30 days, p0.01). Patient preference on same-day discharge was the same regardless of whether they needed a repeat PCI within 30 days (p0.05). Patients for whom early discharge was important were significantly more satisfied with same-day discharge (97.9% versus 79.7% when early discharge was not important, p0.01). Patients who were reluctant to be discharged on the same day of the procedure were significantly less satisfied compared to those who were not (71.9% vs. 96.4% respectively, p0.01). A few patients (8.6%) had difficulty finding transportation home and were significantly less satisfied (70.0% vs. 90.3% when they found transportation easily, p0.01). In conclusion, same-day discharge is preferred by the majority of the patients undergoing radial PCI.

Transradial percutaneous coronary intervention (PCI) is a safe and effective method of percutaneous revascularization. However, there are no data on the efficacy of the transradial approach in left main (LM) PCI. We studied 80 patients (pts) who underwent LM PCI between February 1994 and January 2002, and compared the radial (27 pts) and femoral (53 pts) approaches. Patients were considered free of restenosis if they were free of angina and had a negative treadmill or nuclear imaging study 6 months post-PCI. Mean follow-up time was 27.4+/-23.0 months. Reason for PCI (stable angina, unstable angina, acute myocardial infarction) and lesion location (ostial, mid, distal) were similar in both groups (p0.05), whereas mean ejection fraction was higher in the radial group (56.5+/-11.1% versus 49.2+/-14.7%, respectively; p0.05). Sheath size (7 or 8 French; 44.4% radial versus 77.3% femoral) and amount of heparin used (9,192+/-3,645 IU versus 11,468+/-5,083 IU) were significantly larger in the femoral group (p0.05), and the use of intra-aortic balloon pump was significantly more frequent (3.7% versus 22.6%). Mean fluoroscopy time (21.3+/-12.8 minutes versus 16.7+/-8.5 minutes), amount of contrast used (227+/-92 ml versus 225+/-85 ml), mean procedural time (67.0+/-27.6 minutes versus 73.4+/-32.7 minutes), procedure success (96.3% versus 98.1%), in-hospital major adverse cardiac events (MACE; 7.4% versus 5.6%) and 6-month MACE (14.8% versus 25.5%) were similar in the 2 groups (p0.05). However, major vascular complications occurred only in the femoral group (5.7%). Radial LM PCI is as fast and successful as the femoral approach and results in fewer vascular complications.

A cross-sectional survey was conducted to examine current Canadian practices in the nursing and medical management of femoral arterial sheath removal (SR) after PTCA (percutaneous transluminal coronary angioplasty). The purposes of the study were to (a) investigate the roles of the nurses and physicians in SR, (b) assess the length of time arterial sheaths are left in place and patients kept on bedrest, and (c) describe the routine medical protocols used for pain and anticoagulation therapy. Of the 35 hospitals that perform PTCA in Canada, 30 responded to the survey (response rate of 86%). Nurses had primary responsibility for SR in 13% of the sites and shared responsibility with physicians for SR in a further 10% of the institutions. When nurses were trained to remove sheaths, they assumed responsibility for the adjunctive steps to establish hemostasis. One third of hospitals removed sheaths in 4 hours or less; approximately 75% of them removed sheaths in 6 hours or less after PTCA. Patients are kept on bedrest for 6 hours or less following hemostasis in half, and 8 hours or less at three-quarters of the hospitals. Post-PTCA and pre-SR anticoagulant monitoring was used in almost half of the sites. Premedication for SR varied from no premedication to combinations of three intravenous medications plus local anaesthetic. Survey results showed that in almost one quarter of the Canadian institutions where PTCA is performed, nurses play a role in SR. Results also showed that there is no uniformity in post-PTCA SR across Canada and that further research is needed to identify the optimum approach to managing this common cardiovascular procedure.

To assess the level of use of acetylsalicylic acid (ASA), beta-blockers and thrombolytic therapy--proven efficacious therapies in the management of acute myocardial infarction (AMI)--in contemporary patients admitted with AMI, and to assess the role of contraindications and other patient-specific factors in the use or nonuse of these treatments.The demographics and treatment course of patients admitted with a diagnosis of AMI were reviewed. Specifically targeted therapies were ASA, beta-blockers and thrombolytic therapy. Rates of use were calculated as 'gross utilization' (overall use) and 'adjusted utilization' (accounting for late presentation to hospital, initially equivocal diagnosis or contraindications).Tertiary care hospital in suburban Vancouver, British Columbia.A total of 372 consecutive patients admitted to Royal Columbian Hospital between September 1, 1990 and September 1, 1991.None.Gross utilization of ASA, beta-blockers and thrombolytic therapy was 71, 31 and 21%, respectively. The adjusted utilization rates for early (6 h or less) treatment with ASA was 66%; with early beta-blockers, it was 18% and was 100% for thrombolytic therapy. Adjusted late (more than 6 h, to hospital discharge) use of ASA and beta-blockers was 84 and 57%, respectively.With the exception of thrombolytic therapy, proven efficacious medical therapies for AMI appear underused at the study hospital. Ongoing educational efforts and continuing patterns of practice analyses are needed.

Coronary bypass performed with moderate systemic hypothermia (25 degrees C) and cold-potassium cardioplegia was associated with a fall and subsequent rise in core (pulmonary arterial) temperature. Serial hemodynamic measurements during rewarming and recovery revealed a decrease in cardiac index (CI) without a decrease in the left atrial pressure (LAP) of 17 patients recovering from uneventful coronary bypass surgery. Nuclear ventriculograms performed during rewarming demonstrated a decrease in left ventricular end-diastolic volume index (EDVI, calculated from the thermodilution stroke index divided by the nuclear ejection fraction) without a change in LAP. Volume loading during both mild hypothermia (35 +/- 5[SD]degrees C) and normothermia revealed that myocardial performance (the relation between CI and EDVI) was unchanged, but diastolic compliance (the relation between LAP and EDVI) decreased with rewarming. LAP was a poor indicator of left ventricular preload (EDVI) during rewarming, and volume loading was required to maintain preload and prevent hypoperfusion.

Cold potassium cardioplegia provides adequate protection for coronary bypass operations, but severe coronary stenoses limit cardioplegic delivery to ischemic regions. The traditional technique delivers cardioplegic solution into the aortic root during the performance of distal anastomoses. The proposed alternative technique constructs proximal as well as distal anastomoses during a prolonged cross-clamp period, but permits more uniform cooling. The two techniques were compared in a prospective concurrent trial of 45 patients undergoing elective coronary bypass grafting. The traditional technique was employed in 26 patients (Group A) and the alternative technique in 19 patients (Group B). In both groups, 700 to 1,000 ml of a crystalloid cardioplegic solution was infused into the aortic root after application of the aortic cross-clamp. In Group A (traditional technique), 500 ml was infused into the aortic root after each distal anastomosis. In Group B (alternative technique), cardioplegic solution was administered through the vein graft after each distal anastomosis, and a proximal anastomosis was constructed after distal anastomoses to the most ischemic regions to permit continued cardioplegic delivery to these regions. The cross-clamp period was shorter in Group A than in Group B (44 +/- 15 versus 60 +/- 18 minutes, p less than 0.01), but the mean temperature in the most ischemic region was warmer (Group A, 19 degrees +/- 3 degrees C; Group B, 15 degrees +/- 3 degrees C, p less than 0.05). The postoperative CK-MB was higher in Group A (Group A, 47 +/- 36; Group B, 21 +/- 9 IU/L, p less than 0.01). Cardiac lactate production persisted longer in Group A (Group A, 4 +/- 1; Group B, 1 +/- 1 hours postoperatively, p less than 0.05). Volume loading 4 hours postoperatively produced a similar increase in left atrial pressure and cardiac index in both groups. In response to volume loading, Group A patients produced lactate, but Group B patients extracted lactate (change in cardiac lactate extraction: Group A, -1.7 +/- 2.3; Group B, +2.5 +/- 5.1 mg/dl, p less than 0.05). The construction of proximal as well as distal anastomoses during a prolonged cross-clamp period permits more uniform cooling and immediate reperfusion. This alternative technique resulted in less injury (CK-MB release) and more rapid recovery of myocardial metabolism.

Left ventricular function was compared in 18 normal sedentary controls (mean age 28 years, range 22 - 34 years) and nine endurance-trained athletes (mean age 19 years, range 15 - 25 years) at rest and during supine bicycle exercise. Gated radionuclide angiocardiograms were performed at rest and at each level of graded maximal supine bicycle exercise. Heart rate, blood pressure, left ventricular ejection fraction and the relative changes in left ventricular end-diastolic and end-systolic volumes were assessed. Athletes attained a much greater work load than controls (mean 22.1 kpm/kg body weight vs 13 kpm/Kg body weight). Both groups achieved similar increased in heart rate, blood pressure and ejection fractions. In the controls, the mean end-diastolic volume increased to 124% of that at rest (p less than 0.02) during exercise and the mean end-systolic volume decreased to 81% of the rest level (p less than 0.02). In contrast, the mean end-diastolic volume did not significantly change during exercise in the athletes, and the mean end-systolic volume decreased to 64% of rest (p less than 0.05). Thus, although trained and untrained healthy subjects had similar increases in the left ventricular ejection fraction during exercise, different mechanisms were used to achieve these increases. Untrained subjects increased end-diastolic volumes, whereas trained subjects decreased the end-systolic volumes. The ability of athletes to exercise without increasing preload may be an effect of training amd might have important implications in reducing myocardial oxygen demand during exercise.

Intravenous infusions are required to maintain ventricular preload after uneventful coronary bypass operation. During the early postoperative period, when myocardial metabolic recovery is incomplete, volume loading is intended to stabilize ventricular function and metabolism and to prevent progressive ischemic injury. This study attempts to define the optimal preload for both metabolism and performance. Thirty-seven patients recovering from elective coronary bypass operations and cold potassium cardioplegia underwent volume loading with whole plasma. The initial response (VLA) from a low left atrial pressure (LAP = 7.3 +/- 3.3 mm Hg) was compared with the subsequent response (VLB) from a higher filling pressure (LAP = 10.9 +/- 2.7 mm Hg). Both VLA and VLB produced a similar increase in cardiac index, stroke work index, and end-diastolic volume index (EDVI), and a decrease in ejection fraction (measured by nuclear angiography). Myocardial lactate extraction increased with VLA, but myocardial lactate production resulted with VLB. A careful analysis of these volume loading studies suggested that myocardial performance and compliance were not altered in the early postoperative period. The decrease in ejection fraction with volume loading may have resulted from a combination of increased wall tension and decreased inotropic stimulation. After uneventful coronary bypass surgery, an LAP between 5 and 12 mm Hg corresponded to an EDVI between 30 and 80 ml/m2 and produced adequate cardiac index, stroke work index, and lactate extraction. A lower or higher preload did not improve function and resulted in abnormal metabolism.

Cold potassium cardioplegia provides adequate protection for coronary bypass operations, but severe coronary stenoses limit cardioplegic delivery to ischemic regions. The traditional technique delivers cardioplegic solution into the aortic root during the performance of distal anastomoses. The proposed alternative technique constructs proximal as well as distal anastomoses during a prolonged cross-clamp period, but permits more uniform cooling. The two techniques were compared in a prospective concurrent trial of 45 patients undergoing elective coronary bypass grafting. The traditional technique was employed in 26 patients (Group A) and the alternative technique in 19 patients (Group B). In both groups, 700 to 1,000 ml of a crystalloid cardioplegic solution was infused into the aortic root after application of the aortic cross-clamp. In Group A (traditional technique), 500 ml was infused into the aortic root after each distal anastomosis. In Group B (alternative technique), cardioplegic solution was administered through the vein graft after each distal anastomosis, and a proximal anastomosis was constructed after distal anastomoses to the most ischemic regions to permit continued cardioplegic delivery to these regions. The cross-clamp period was shorter in Group A than in Group B (44 +/- 15 versus 60 +/- 18 minutes, p less than 0.01), but the mean temperature in the most ischemic region was warmer (Group A, 19 degrees +/- 3 degrees C; Group B, 15 degrees +/- 3 degrees C, p less than 0.05). The postoperative CK-MB was higher in Group A (Group A, 47 +/- 36; Group B, 21 +/- 9 IU/L, p less than 0.01). Cardiac lactate production persisted longer in Group A (Group A, 4 +/- 1; Group B, 1 +/- 1 hours postoperatively, p less than 0.05). Volume loading 4 hours postoperatively produced a similar increase in left atrial pressure and cardiac index in both groups. In response to volume loading, Group A patients produced lactate, but Group B patients extracted lactate (change in cardiac lactate extraction: Group A, -1.7 +/- 2.3; Group B, +2.5 +/- 5.1 mg/dl, p less than 0.05). The construction of proximal as well as distal anastomoses during a prolonged cross-clamp period permits more uniform cooling and immediate reperfusion. This alternative technique resulted in less injury (CK-MB release) and more rapid recovery of myocardial metabolism.

Long-term follow-up of aortocoronary bypass has shown good preservation of ventricular function. However, myocardial reserve in the immediate postoperative period may not be optimal. Nineteen patients who underwent elective aortocoronary bypass protected with cold potassium cardioplegia were studied in the early postoperative period at rest and during the stress of atrial and ventricular pacing. Performance was assessed by hemodynamic, metabolic and nuclear angiographic measurements. In the first 2--6 hours after aortic cross clamping, myocardial performance was preserved at rest and there was no evidence of ischemic metabolism. Atrial pacing at a rate of 119 beats/min caused a significant increase in cardiac index (p less than 0.01) without deterioration in hemodynamics, ejection fraction or metabolic status. At the same rate, ventricular pacing did not change the cardiac index and there was a decrease in hemodynamic function. Ejection fraction decreased from 56% to 44% (p less than 0.05) without a change in end-diastolic volume. Lactate, pyruvate and beta hydroxybutyrate extractions were changed to net production. Ventricular performance was preserved at rest immediately after aortocoronary bypass done with multidose cold potassium cardioplegia, with adequate reserve to meet the stress of atrial but not ventricular pacing. We conclude that the therapeutic implications of the type of pacing selected in the immediate postoperative period may be important.