Conserving large carnivores: dollars and fence.

Conservationists often advocate for landscape approaches to wildlife management while others argue for physical separation between protected species and human communities, but direct empirical comparisons of these alternatives are scarce. We relate African lion population densities and population trends to contrasting management practices across 42 sites in 11 countries. Lion populations in fenced reserves are significantly closer to their estimated carrying capacities than unfenced populations. Whereas fenced reserves can maintain lions at 80% of their potential densities on annual management budgets of $500 km(-2) , unfenced populations require budgets in excess of $2000 km(-2) to attain half their potential densities. Lions in fenced reserves are primarily limited by density dependence, but lions in unfenced reserves are highly sensitive to human population densities in surrounding communities, and unfenced populations are frequently subjected to density-independent factors. Nearly half the unfenced lion populations may decline to near extinction over the next 20-40 years.

Effect of supplementation of probiotics and phytosterols alone or in combination on serum and hepatic lipid profiles and thyroid hormones of hypercholesterolemic rats.

Probiotic bacteria and phytosterols are natural hypocholesterolemic agents with potential cardiovascular benefits. Accordingly, the present study was conducted to evaluate the effect of supplementation of probiotics and phytosterols alone or in combination on serum and hepatic lipid profiles and thyroid hormones of hypercholesterolemic rats. Mixed probiotics treatment consisted of 8 probiotic strains: 2 strains of each of Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus gasseri, and Lactobacillus reuteri. The rats were fed for 8 wk with the given treatments in addition to a high-fat-high-cholesterol basal diet to induce hypercholesterolemia. Results showed that supplementation significantly reduced serum total cholesterol, low-density-lipoprotein cholesterol (LDL-C), high-density-lipoprotein cholesterol, and triglycerides compared with the controls. The symbiotic treatment was more effective in lowering LDL-C, whereas mixed probiotics treatment more effectively lowered serum total cholesterol and LDL-C than the phytosterol-containing treatment. The phytosterol-containing treatments induced the increased activity of thyroid glands, as evident by elevated levels of serum total thyroxine, total triiodothyronine, and free triiodothyronine. In conclusion, the lipid profile can effectively be reduced to lower the incidence of cardiovascular disease using combinations of Lactobacillus-based probiotics and phytosterols in functional foods.

Alternative method of ultrafiltration after cardiopulmonary bypass.

A revised circuit design for modified ultrafiltration is presented rendering the technique more convenient for use after cardiopulmonary bypass when blood cardioplegia is used. The procedure employs a hollow-fiber ultrafiltration device attached to the cardioplegia circuit. A bubble trap, heat exchanger, and a pressure monitor are incorporated as safety features. The technique has been used in 80 patients (30 pediatric and 50 adult) and has been associated with relevant increases in colloid osmotic pressure and hematocrit.

Lowest hematocrit on bypass and adverse outcomes associated with coronary artery bypass grafting. Northern New England Cardiovascular Disease Study Group.

BACKGROUND: Cardiac surgery patients' hematocrits frequently fall to low levels during cardiopulmonary bypass. METHODS: We investigated the association between nadir hematocrit and in-hospital mortality and other adverse outcomes in a consecutive series of 6,980 patients undergoing isolated coronary artery bypass graft surgery. The lowest hematocrit during cardiopulmonary bypass was recorded for each patient. Patients were divided into categories based on their lowest hematocrit. Women had a lower hematocrit during bypass than men but both sexes are represented in each category. RESULTS: After adjustment for preoperative differences in patient and disease characteristics, the lowest hematocrit during cardiopulmonary bypass was significantly associated with increased risk of in-hospital mortality, intra- or postoperative placement of an intraaortic balloon pump and return to cardiopulmonary bypass after attempted separation. Smaller patients and those with a lower preoperative hematocrit are at higher risk of having a low hematocrit during cardiopulmonary bypass. CONCLUSIONS: Female patients and patients with smaller body surface area may be more hemodiluted than larger patients. Minimizing intraoperative anemia may result in improved outcomes for this subgroup of patients.

Hot years and serious and deadly assault: empirical tests of the heat hypothesis.

Two archival studies examined the relation between year-to-year shifts in temperature and violent and property crime rates in the United States. Study 1 examined the relation between annual average temperature and crime rate in the years 1950-1995. As expected, a positive relation between temperature and serious and deadly assault was observed, even after time series, linear year, poverty, and population age effects were statistically controlled. Property crime was unrelated to annual average temperature. Study 2 examined the relation between the average number of hot days (> or = 90 degrees F) and the size of the usual summer increase in violence for the years 1950-1995. As expected, a positive relation was observed between number of hot days and magnitude of the summer effect, even after time series and linear year effects were statistically controlled. For property crime, the summer effect was unrelated to number of hot days.

Outcomes analysis in cardiac surgery.

Outcomes research is a quantitative assessment of the results of care. Outcomes analysis provides information that benefits the physician, the patient, the institution and the health care purchasers. It provides relevant and timely information for the assessment of the heart centre's performance. Outcomes data have proven to be useful to the attending physicians by providing a basis for clinical decision making. Patients may be appraised of the usual results and the risks of various treatment strategies and make informed decisions on their care. The purchasers of health care will be better informed regarding the costs and effectiveness of the care being delivered. O'Connor et al. have stated that methods of improving care are often discussed but are difficult to achieve due to processes of care being hidden from view. Outcomes research is a comprehensive performance evaluation strategy that may be used to discover the impact of these hidden aspects of care. This technology of the patient's experience is bringing cardiac surgery to a new level of excellence.

Mice and monkeys as assay animals for Clostridium perfringens food poisoning.

Spores and vegetative cells of Clostridium perfringens, in combination with meat or starch paste, sterile culture filtrates, lecithinase, and phosphorylcholine, were administered to mice and rhesus monkeys in an attempt both to evaluate the animals as test agents and, if possible, to elucidate the active factors producing food-poisoning symptoms caused by this organsim. Some of the preparations were administered to the monkeys by stomach tube; others, in gelatin capsules which were treated with formaldehyde so that the release of their contents was delayed and presumably reached the intestines of the animals. Any changes in intestinal passage times and in consistency of stools of the animals were observed, and the counts of C. perfringens in the feces of the monkeys previous and subsequent to treatment were recorded. The results obtained were inconclusive. Diarrhea occurred only relatively infrequently in both species, regardless of the substance fed or the mode of administration. The changes in intestinal passage times were not great, although in the monkeys there appeared to be a slight trend toward reduction as the magnitude of the bacterial load increased. Phosphorylcholine appeared to have little, if any, effect in reducing intestinal passage time of mice or monkeys. No procedures explored in these experiments could be said to be satisfactory as a means of animal assay for food poisoning strains of C. perfringens since typical symptoms did not appear with regularity.

Size makes a difference: use of a low-prime cardiopulmonary bypass circuit and autologous priming in small adults.

Low hematocrit (Hct < 20) during cardiopulmonary bypass (CPB) is associated with higher mortality and other adverse outcomes. More frequently, low Hct is encountered in patients with small body size and women patients. This prompted us to take an aggressive approach in our care of these patients, involving a strategy for predicting patients at risk of low Hct, with the aid of an electronic worksheet that accurately predicts CPB Hct, and two prevention strategies: use of a low-prime CPB circuit (LP) for all adult patients with a body surface area (BSA) < 1.7 m(2) and use of autologous circuit priming (AP), in addition to the low-circuit volume in some patients. The two cohorts of patients in whom these techniques were employed were compared to a group matched for body size where our standard adult circuit (STD) was used. There were 233 patients in the standard group, 139 in the LP group, and 68 in the LP/AP group. The CPB circuit prime volume was 1,710 ml for the STD group and 1,110 ml for the LP group. Use of autologous priming techniques further reduced the prime volume by 545 +/- 139 ml. The incidence of low Hct (<20%) during CPB was thus reduced from 70% to 15% (p = 0.001) when using both techniques together without increasing red blood cell (RBC) transfusions. These changes in perfusion management resulted in a reduction in the incidence of renal complications (STD = 9.4%, LP = 6.5% (ns) and LP/AP = 0%,

Cardiac assist devices.

The two primary goals of mechanical circulatory support are to provide adequate perfusion of the vital organs and to decrease cardiac work. The support of the myocardium is in an effort to cause a reversal of cardiac damage. The recovery process apparently takes place in two stages. Initially, there is a rapid functional recovery of cells in marginally ischemia areas. Then there is a slower process of hypertrophy of normal and recovering myofibers. The process involves the reversal of interstitial and of intercellular myocardial edema in areas of viable myocardium while halting the extension of necrosis into reversibly ischemic areas. It appears that this process is extended from 3 to 5 days, and functional recovery can occur for up to 2 weeks. After a 2-week period, there appears to be little functional recovery of myocardial cells. In autopsy series of nonsurvivors, it appears that most of the patients had suffered from biventricular failure. Biventricular failure appears to be one of the more common complications of the support patient. Right ventricular failure will be attempted to be supported by right ventricular assist devices. The right ventricular assist device, unfortunately, adds a level of complication to the recovery process for the bridge-to-transplant or cardiomyopathy patient. The patients who are involved in support fall into three categories: (1) the bridge-to-transplant patient, (2) the patient recovering from postcardiotomy, and (3) the patient who recovers from an acute myocardial insult. It appears that after 2 weeks the recovery period for all of these groups demonstrates no further functional recovery. The bridge-to-transplant patients usually need to be supported until the transplant occurs. The postcardiotomy patient and the acute myocardial failure patient are the most disappointing support group, since they have a higher morbidity and mortality, and a lower chance of recovery. Salvage rates appear to be in approximately the 25% range in the acute insult category.

Pediatric cardiopulmonary bypass: a review of current practice.

Devices and techniques used for pediatric cardiopulmonary bypass are ever changing. There are frequently reports in the literature about new techniques and new devices. Periodic surveys are helpful because they reveal the actual extent to which these techniques and devices are applied to clinical practice. Advances in research are bringing about a better understanding of the intricate aspects of CPB and the effects of CPB on pediatric patients. There appears to be a trend from widely divergent approaches to CPB for pediatric patients to more uniformity in practice. For example, the use of membrane oxygenation and arterial line filtration has become universal, and there is an increase in the use of all types of safety devices. Techniques reported in the medical literature at the beginning of the decade, such as, the use of modified ultrafiltration, the use of centrifugal cell washers to process packed red blood cells before adding them to the prime, and the use of the antifibrinolytic drug, aprotinin, have become part of practice at a large number of pediatric heart centers. Periodic surveys are useful, as they provide a measurement of current practice. They also provide a historical record of the advances in the field.

Parallel replacement of the oxygenator that is not transferring oxygen: the PRONTO procedure.

We present here a technique to replace a failed oxygenator by inserting a second oxygenator in parallel (PRONTO) within the cardiopulmonary bypass (CPB) circuit. Oxygenator failure is a potential hazard that may result in patient injury or death. Although failures are rare, safety surveys conducted over the last 25 years suggest that the incidence of oxygenator failures is on the rise. This emergency procedure may be easily applied to any standard CPB circuit with a few minor alterations. The technique is simple; it can be carried out rapidly. An important advantage of this technique is that it may be executed without interrupting blood flow to the patient, which may reduce the incidence of patient injury or death.

Procurement for a comprehensive cancer center.

The director of materials management services at M.D. Anderson is a position of endless opportunities, as well as continual challenges. The procurement process provides the opportunity to be an integral part of a team that has made a significant difference to many of the patients in the areas of cancer prevention, education, detection, diagnosis, treatment, cure, and rehabilitation. All involved in health care purchasing derive a personal fulfillment not available to purchasers in other industries. At MDA, however, this goes even one step further, as our department supports a team in the battle against cancer--a battle that affects nearly every household in America today. MDA can state that more than half of all patients treated are considered cured, and that is certainly a great team with which to be associated. But even more exciting are the years to come, as materiel management services supports the M.D. Anderson mission of eliminating cancer and allied diseases as significant health problems throughout the world.

The effect of cardiopulmonary bypass on brain and heart metabolism: a 31P NMR study.

The development of a large animal preparation using 31P nuclear magnetic resonance (NMR) spectroscopy for the study of cerebral and myocardial metabolism during cardiopulmonary bypass (CPB) is reported. The effect of normothermic CPB on myocardial and cerebral metabolism was evaluated. Adolescent sheep were used which have low levels of 2,3-diphosphoglycerate, a compound which can interfere with the calculation of intracellular pH and inorganic phosphate content. CPB was performed using standard procedures modified for the presence of a high magnetic field and limited access to the animal. High quality 31P NMR data were obtained from the brains and hearts of these animals before and during normothermic CPB. These results demonstrate that the initiation of normothermic CPB does not change high energy phosphate levels or intracellular pH. In particular, the decreased myocardial oxygen demand associated with CPB is not associated with improvement in the levels of adenosine triphosphate or phosphocreatine. The measurements of energy metabolism and intracellular pH of the brain and heart during CPB were possible within the constraints of the NMR experiment without compromising the CPB procedure. Combining NMR and CPB techniques permits future studies of cerebral and myocardial metabolism, especially those relating to ischemia.

A model for cardiopulmonary bypass redesign.

INTRODUCTION: A portion of patients undergoing cardiac surgery may develop focal and/or subtle brain injuries secondary to cardiac surgery. There is evidence that, in some cases, these injuries may be related to cardiopulmonary bypass (CPB). Embolism and hypoperfusion are the dominant mechanisms for focal neurologic injuries among coronary artery bypass graft (CABG) surgery patients. Recent studies suggest that these mechanisms may also produce the more prevalent subtle neurological deficits. The aim of our current work is to obtain a thorough understanding of the processes of care associated with the production of embolic activity, cerebral hypoperfusion, and hemodynamic aberrations that often occur during CPB. METHODS: We developed a system for simultaneous recording of physiologic parameters, embolic activity in the CPB circuit and in the cerebral arteries, and near infrared regional cerebral oxyhemoglobin saturation (NIRS) during cardiac surgery. All data were synchronized with a video recording of the surgical procedure. Periods of embolic activity and NIRS were subsequently related to surgical and CPB processes of care through a systematic review of the patient's surgical case video. RESULTS: To date, we have enrolled 47 patients undergoing coronary and/or valvular procedures. We have observed wide variation across patients in detected cerebral embolic counts, NIRS and physiologic parameters. We have identified increased embolic counts in the CPB circuit related to specific processes and events such as the method of venous drainage, the entrainment of air in the venous line, the injection of medications into the CPB circuit and blood sampling from the CPB circuit. A portion of detected changes in NIRS were related to periods of hypotension and positioning of the heart during the construction of distal coronary artery grafts on the posterior coronary artery vessels. SUMMARY: Use of this model provides the surgical team with detailed information regarding the contribution of CPB to the creation of precursors of neurological injury. This system provides meaningful data to guide the surgical team in the redesign of the CPB system and associated techniques.

Paediatric perfusion practice in North America: an update.

In August 1994, an updated survey questionnaire was mailed to each paediatric open-heart surgery programme in North America as a follow-up to the 1989 paediatric survey. The survey requested demographic data, equipment selection criteria and specific perfusion techniques for paediatric patients. The earlier survey revealed a wide range of clinical practice. Data from the recent survey were compared with the 1989 survey to identify current programme demographics and trends in equipment use and techniques. Responses were received from 125 hospitals (110 active programmes and 15 programmes that do not perform paediatric open-heart surgery) for a response rate of 74%. Of the 110 active centres, 77 perform both adult and paediatric cardiac surgery, and 33 perform paediatric surgery exclusively. Forty-three centres reported that they perform paediatric cardiac transplantation, an increase from 35 centres in 1989. Total caseload increased by more than 8% per year from 1988 to 1994. In 1994, 18% of the patients were operated upon during the first month of life (versus 15% in 1989), and 46% were operated on during the first year of life (versus 45% in 1989). While the 1989 survey was characterized by a high degree of heterogeneity in equipment and techniques, the recent survey reveals a trend toward homogeneity among respondents. The use of membrane oxygenation and arterial line filtration has become universal, and there was an increase in the use of all types of safety devices in the cardiopulmonary bypass circuit.

Intra-operative quality assessment of coronary artery bypass grafts.

Early coronary artery bypass graft (CABG) failure is a troubling complication that may result in a wide range of problems, including refractory angina, myocardial infarction, low cardiac output, arrhythmia, and fatal heart failure. Early graft failures are related to poor quality and size of the distal native vascular bed, coagulation abnormalities, or technical problems involving the graft conduits and anastomoses. Unfortunately, graft failure is difficult to detect during surgery by visual assessment, palpation, or conventional monitoring. We evaluated the accuracy and utility of a transit-time, ultrasonic flow measurement system for measurement of CABGs. There were no differences between transit-time measurements and volumetric-time collected samples in an in vitro circuit over a range of flows from 10 to 100ml/min (Bland and Altman Plot, 1.96 SD). Two hundred and ninety-eight CABGs were examined in 125 patients. Graft flow rate was proportional to the target vessel diameter. Nine technical errors were detected and corrected. Flow waveform morphology provided valuable information related to the quality of the anastamosis, which led to the immediate correction of technical problems at the time of surgery.