A new method for estimating species age supports the coexistence of malaria parasites and their Mammalian hosts.

Species in the genus Plasmodium cause malaria in humans and infect a variety of mammals and other vertebrates. Currently, estimated ages for several mammalian Plasmodium parasites differ by as much as one order of magnitude, an inaccuracy that frustrates reliable estimation of evolutionary rates of disease-related traits. We developed a novel statistical approach to dating the relative age of evolutionary lineages, based on Total Least Squares regression. We validated this lineage dating approach by applying it to the genus Drosophila. Using data from the Drosophila 12 Genomes project, our approach accurately reconstructs the age of well-established Drosophila clades, including the speciation event that led to the subgenera Drosophila and Sophophora, and age of the melanogaster species subgroup. We applied this approach to hundreds of loci from seven mammalian Plasmodium species. We demonstrate the existence of a molecular clock specific to individual Plasmodium proteins, and estimate the relative age of mammalian-infecting Plasmodium. These analyses indicate that: 1) the split between the human parasite Plasmodium vivax and P. knowlesi, from Old World monkeys, occurred 6.1 times earlier than that between P. falciparum and P. reichenowi, parasites of humans and chimpanzees, respectively; and 2) mammalian Plasmodium parasites originated 22 times earlier than the split between P. falciparum and P. reichenowi. Calibrating the absolute divergence times for Plasmodium with eukaryotic substitution rates, we show that the split between P. falciparum and P. reichenowi occurred 3.0-5.5 Ma, and that mammalian Plasmodium parasites originated over 64 Ma. Our results indicate that mammalian-infecting Plasmodium evolved contemporaneously with their hosts, with little evidence for parasite host-switching on an evolutionary scale, and provide a solid timeframe within which to place the evolution of new Plasmodium species.

Repeat surgery for coronary artery bypass grafting: the role of the left thoracotomy approach.

OBJECTIVE: Repeat coronary artery bypass surgery has increased risks compared with the first operation, including low cardiac output and injury to patent grafts. The left thoracotomy approach has been advocated specifically in patients with intact grafts of the left internal mammary artery (LIMA) to the left anterior descending coronary artery (LAD) needing lateral wall grafting. We have evaluated this technique in conjunction with an off-pump procedure in all patients. METHODS: There were 55 patients over an 8-year period, and 6 (10.9%) were female. The mean age was 63.2 years (range, 41-82 years), and the age at the time of the previous operation was 51.7 years (range, 31-69 years). Four patients (7.2%) underwent a third operation. Comorbidities were diabetes mellitus (25 patients, 45.5%), renal impairment (8 patients, 14.5%), calcified ascending aorta (9 patients, 16.4%), carotid disease (4 patients, 7.2%), and peripheral vascular disease (11 patients, 20.0%). Fifteen patients (27.2%) had previous coronary stents. Nine patients (16.4%) had a preoperative intra-aortic balloon pump. Predicted mortality (logistic EuroSCORE) was 14.2%. RESULTS: Forty-three patients (78.1%) had intact LIMA-to-LAD grafts. Twenty-two patients (40.0%) required a major posterolateral thoracotomy, and 33 patients (60.0%) had a minor thoracotomy. Thirteen patients (23.6%) had stents placed as a hybrid procedure during the same admission. Thirteen patients (23.6%) additionally underwent anterior wall grafting (LAD to the first marginal area). The LIMA was used in 7 patients where it had not been used before. There were 91 distal grafts (including 4 sequentials). We performed 54 venous grafts and 26 radial artery grafts. Twenty-one patients (38.1%) had 1 distal graft, 32 patients (58.1%) had 2 grafts, and 2 patients (3.6%) had 3 distal grafts performed (mean, 1.6 grafts/patient). The proximal graft site was the proximal descending aorta in 20.0% of the patients, the distal aorta in 67.5%, and the subclavian artery in 12.5%. In 10 patients (18.2%), the distal branches of the right coronary (posterior descendens or right posterolateral) were grafted. No patient required conversion to cardiopulmonary bypass or sternotomy. No patient needed an intra-aortic balloon pump postoperatively. The mean blood loss (24 hours) was 380 mL (range, 125-1100 mL), the mean ventilation time was 4.8 hours (range, 0-12 hours), the mean intensive care unit stay was 2.7 days (range, 2-8 days), and the mean hospital stay was 6.3 days (range, 5-20 days). There was 1 postoperative death (1.8% mortality). One late death occurred on follow-up. Four patients underwent cardiac catheterization for chest pain, and the grafts were shown to be open. CONCLUSION: The procedure is safe, especially in patients with intact LIMA-to-LAD grafts needing lateral and inferior wall revascularization. Multislice computed tomography scanning allows better preoperative planning, especially regarding the site of implantation of the proximal graft, allowing a less invasive incision. The off-pump technique preserves cardiac and pulmonary function. The in-hospital death rate (1.8%) compares very well with the EuroSCORE-predicted mortality (14.2%).

Delayed pericardial effusion following stab wounds to the chest.

INTRODUCTION: Delayed pericardial effusion following penetrating cardiac trauma has not been commonly reported, and the exact incidence remains unknown. It was more common before 1960, when pericardiocentesis was still a popular treatment for stable patients presenting with a stab wound to the heart. MATERIAL AND METHODS: During an 8-year period, 24 patients were diagnosed with delayed pericardial effusions following a recent stab wound over the chest. Nine patients had been initially treated at our trauma unit, and the remaining 15 patients were referred by a peripheral clinic. RESULTS: Diagnosis was confirmed by cardiac ultrasound or echocardiogram. Sixteen patients were adequately treated by subxiphoid drainage. Sternotomy was performed in five patients, left thoracotomy in two and right thoracotomy in one patient. No actively bleeding injuries were found. Three patients had active infection in the pericardial space. Fever, pleural effusions and ascites were common associated findings. Additional procedures performed included laparotomy for acute abdominal pain in two patients (both negative), and simultaneous drainage of a pleural empyema. Two patients with staphylococcal pericardial infections required subsequent pericardiectomy. SUMMARY: The diagnosis of a penetrating cardiac patient may be missed in a stable patient, and patients may present with delayed pericardial effusions and tamponade. Post pericardiotomy syndrome may be the most common cause of delayed pericardial effusion, followed by sepsis. Subxiphoid pericardial window is an adequate form of treatment. Recent literature reveals that occult cardiac injury is not uncommon, thus a case should be made to actively investigate all patients with precordial stab wounds with cardiac ultrasound or echocardiogram.

Pericardial rupture and cardiac herniation after blunt chest trauma.

Pericardial rupture after blunt chest trauma is rare and is associated with a high mortality rate. We describe a patient with traumatic pericardial rupture and cardiac herniation who was successfully treated surgically. Traumatic pericardial rupture is difficult to diagnose preoperatively but should be suspected whenever there is severe blunt chest trauma. If pericardial rupture is not recognized and treated promptly it could be fatal owing to cardiac herniation.