Diet of Juvenile Alabama Shad (Alosa alabamae) in Two Northern Gulf of Mexico Drainages

Understanding food-web ecology is valuable to conservation by linking interactions of multiple species together and illustrating the functionality of trophic exchange. Alosa alabamae (Alabama Shad), an anadromous species, reproduces in northern Gulf of Mexico drainages from February through May, and for this study, the Pascagoula and Apalachicola rivers were chosen to sample juvenile Alabama Shad. The age-0 fish mature within these rivers and have the potential to impact the food web of the systems in which maturation occurs. The focus was to determine if diet changes as Alabama Shad mature, and to identify diet differences between drainages. Diets of Alabama Shad (SL) consisted primarily of a dark, almost black material labeled as unidentifiable organics. while larger Alabama Shad. \u3e50 mm SL, fed almost exclusively on insects. Many groups of aquatic and terrestrial insects were found in the stomachs of this species. Alabama Shad diets also differed among drainages, with the Apalachicola River being dominated by terrestrial insects, and the Pascagoula River having both terrestrial and aquatic insects. Diet and trophic placement of Alabama Shad may allow managers to understand the importance of this fish within its natal rivers

Optimal flow rates for integrated cardioplegia

AbstractBackground: Antegrade cardioplegic delivery may be impaired by coronary occlusions, whereas retrograde delivery of cardioplegic solution may be inhomogeneous, leading to an accumulation of lactate and hydrogen ions, the products of anaerobic metabolism. Integrated cardioplegia using continuous retrograde cardioplegia and antegrade infusions into completed vein grafts washes out metabolites accumulated in regions inadequately perfused by retrograde cardioplegia alone. To determine the flow rates required to achieve the greatest washout, we compared a high flow rate (200 ml/min) to a low flow rate (100 ml/min). Methods: Twenty patients scheduled for isolated coronary bypass surgery were prospectively randomized to compare two flow rates for integrated cardioplegic protection using tepid (29° C) blood cardioplegia. Arterial and coronary sinus blood samples were collected to evaluate myocardial metabolism. After antegrade arrest, cardioplegic solution was delivered by coronary sinus perfusion and simultaneous infusions into each completed vein graft at either high or low flow. Results: Increasing from low to high flow increased the washout of lactate and hydrogen ions during the aortic crossclamp period. Two hours after crossclamp removal, ventricular function was better in the high flow group. Conclusions: Tepid retrograde cardioplegia resulted in an accumulation of toxic metabolites. The addition of antegrade vein graft infusions at a flow rate of 100 ml/min resulted in a washout of these metabolites. A flow rate of 200 ml/min further improved this washout and resulted in improved ventricular function. An integrated approach to myocardial protection using a flow rate of 200 ml/min may improve the results of coronary bypass surgery. (J Thorac Cardiovasc Surg 1998;115:226–35

Vitamin E for coronary bypass operations: a prospective, double-blind, randomized trial

Background: Free radical lipid peroxidation contributes to the abnormal metabolism and ventricular function frequently seen after cardiac operations. Antioxidants may improve metabolic and functional recovery. Methods: A prospective, randomized, double-blind clinical trial was conducted to determine the effects of vitamin E (alpha-tocopherol) (n = 14) or a corn oil placebo (n = 14) in patients undergoing elective coronary bypass operations. The RRR-alpha-tocopheryl acetate doubled the alpha-tocopherol levels in the heart. Myocardial metabolism and ventricular function were assessed after the operation. Results: Atrial pacing induced myocardial lactate production in the control patients but lactate consumption in the alpha-tocopherol\u2013treated patients on bypass 25 minutes after crossclamp release. Left ventricular stroke work indices were higher, at similar ventricular volumes, in the alpha-tocopherol\u2013treated group, which indicates improved preload recruitable stroke work, and diastolic compliance was greater 4 hours after the operation. The postoperative creatine kinase cardiac isoenzyme levels were lower in the patients who received alpha-tocopherol. Conclusions: Pretreatment with alpha-tocopherol sufficient to double the myocardial concentrations had a small but significant metabolic and functional effect after elective coronary bypass operations when compared with placebo. These results do not justify pretreatment of low-risk patients, but they do justify an evaluation in high-risk patients.Peer reviewed: YesNRC publication: Ye