Plant size, latitude, and phylogeny explain within-population variability in herbivory.

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sparse data. We collected standardized surveys of herbivory for 503 plant species at 790 sites across 116° of latitude. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth.

Evaluation of coagulation factors and platelet function from an off-line modified ultrafiltration technique for post-cardiopulmonary bypass circuit blood recovery.

Modified ultrafiltration (MUF) is a technique that hemoconcentrates residual CPB circuit blood and the patient at the same time. Hemoconcentration and MUF are Class 1-A recommendations in the anesthesia and surgical blood conservation guidelines. This study evaluated the off-line MUF process of the Hemobag (HB, Global Blood Resources, Somers, CT, USA) to quantitate coagulation factor levels, platelet (PLT) count and function in one facility and cellular growth factor concentrations of the final product that were transfused to the patient in another facility In two cardiac surgery facilities, after decannulation, the extracorporeal circuit (ECC) blood from 22 patients undergoing cardiac surgery was processed with the HB device. In eleven patients from the first facility by the study design, blood samples for coagulation factor levels and PLT aggregation were drawn from the reservoir of the MUF device pre- and post-processing. The samples (n = 11) were sent to a reference laboratory where testing for prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), reptilase time, fibrinogen, clotting factors II, V, VII, VIII, IX, X, ADAMTS-13, protein C, protein S, antithrombin III, von Willebrand Factor (vWF), and platelet (PLT) aggregation were performed. A portion of the final concentrated HB blood samples (n = 5-10) from the second facility by design were evaluated for transforming and platelet-derived cellular growth factor concentrations. On average, approximately 800 - 2000 mls of whole blood were removed from the ECC post-CPB for processing in the HB device. After processing, there was, on the average, approximately 300 - 950 mls of concentrated whole blood salvaged for reinfusion. The PT and INR were significantly lower in the post-processing product compared to the pre-processing samples while the aPTT times were not significantly different. All coagulation factors and natural anti-coagulants were significantly increased in the final product. The PLT number, although increased by 24%, was not statistically significant. While PLT function assays showed a statistically significant decrease in the levels post-processing, there was substantial platelet function in the MUF product. Overall, the decrease in function was in the range of 10% to 15%. Final product PDGF-αß and TGF-ß1 averaged 11,048 and 2,040 pg/ml, respectively. In these two case series, (ECC) circuit blood concentrated using the HB device showed coagulation studies with significantly lower PT and INR and significantly increased levels of all clotting factors. The findings are similar to trends reported in other studies utilizing conventional MUF and the HB. Functioning platelets remain in the final product, with growth factor concentrations similar to some methods employed to create platelet concentrates to enhance coagulation. Based on the ability of the HB off-line MUF procedure to concentrate circuit blood, the clinical utility of the HB device to decrease allogeneic blood product exposure should be evaluated in a prospective randomized clinical trial.

Cell death in human acute myelogenous leukemic cells induced by pyrrolidinedithiocarbamate.

Pyrrolidinedithiocarbamate (PDTC) is a metal chelating compound, which exerts both pro-apoptotic effect and pro-oxidant activity on many cells. Our objective was to investigate whether PDTC was able to interfere with apoptotic process in leukemic and normal bone marrow CD34+ cells. Since hematopoietic growth factors stimulate growth and differentiation and prevent apoptosis, we therefore studied the effect of growth factors pretreatment, such as interleukin-3 and granulocyte-macrophage colony stimulating factor, in human myeloid CD34+ cells to evaluate whether they protect the cells from the apoptotic action of PDTC. We revealed that PDTC exerted an apoptotic effect in leukemic CD34+ cells. This effect was dependent on the ability of this compound to generate the oxidation of cellular glutathion to its disulphide and consequently to induce an intracellular oxidative stress. Hematopoietic growth factors did not protect cells from apoptosis induced by previous treatment with PDTC. The ability of PDTC to induce apoptosis was restricted to acute myelogenous leukaemia CD34+ cells, since normal CD34+cells were insensitive to the pro-oxidant effect of PDTC. These findings imply that normal cells are equipped with mechanisms by which they respond differently to PDTC effects with respect to leukemic cells.

Augmentative and alternative communication to support receptive and expressive communication for people with autism.

In this article the authors discuss the use of augmentative and alternative communication (AAC) as used to enhance comprehension and expression of people with autism. A theoretical model for AAC assessment and intervention planning is presented. Application of the model is illustrated through a case report of a 6-year-old boy with autism who had severe expressive and receptive language impairments.

Circulating serum levels of IL-1ra in patients with relapsing remitting multiple sclerosis are normal during remission phases but significantly increased either during exacerbations or in response to IFN-beta treatment.

Interleukin (IL)-1 receptor antagonist (IL-1ra) is a naturally occurring inhibitor of IL-1 which binds to IL-1 receptors without generating immunologic responses. Evidence has recently been provided that the balance between the production of IL-1 and IL-1ra might influence the course of immunoinflammatory diseases such as inflammatory bowel diseases, rheumatoid arthritis (RA) and Lyme arthritis. To assess whether endogenous IL-1ra may also have a role on the course of multiple sclerosis (MS) we presently studied the fluctuation of the serum levels of IL-1ra in patients with relapsing remitting (RR) MS either during remission or exacerbation. Moreover, to evaluate whether the beneficial effect of IFN-beta on the course of MS might also be mediated by an increased production of IL-1ra, we measured the levels of circulating IL-1ra in MS patients prior to and after 6 months of continuous treatment with natural human IFN-beta (6,000,000 IU three times a week for 6 months). Our results demonstrated that, relative to control subjects, IL-1ra serum levels are "normal' during remitting phases of RR MS but significantly elevated either during exacerbations or in response to IFN-beta treatment.

Pneumonectomy for unremitting hemoptysis in unilateral absence of pulmonary artery.

Unilateral absence of pulmonary artery is a rare malformation that can present as an isolated lesion or may be associated with other congenital heart defects. Clinical presentation is subtle when the lesion occurs alone, and may include hemoptysis, which results from rupture of abundant bronchial submucosal vessels perfused by enlarged systemic collaterals that supply the affected lung. Pneumonectomy is recommended as definitive treatment in such an adult patient.

Normothermic retrograde continuous cardioplegia for myocardial protection during cardiopulmonary bypass. A modified technique.

Normothermic retrograde continuous cardioplegia is a revolutionary development for myocardial preservation in cardiac surgery. Despite excellent reports regarding this technique, the surgical community has expressed concern over technical problems encountered. The method of normothermic retrograde continuous cardioplegia in current use requires both large total crystalloid volumes and large potassium loads to deliver adequate cardioplegia. We have developed a technique that eliminates these problems. The heart is stopped by an initial infusion of normothermic cardioplegic solution through a coronary sinus catheter. The infusate is then converted to normothermic pump blood. Small boluses of potassium chloride are added intermittently to maintain cardiac arrest. We applied this technique to 35 patients undergoing cardiac valve surgery. The average volume of crystalloid cardioplegia required was 125 mL (range, 40 to 155 mL), and the average total potassium load was 52 mEq (range, 2 to 100 mEq). Clinically significant sequelae were noted in 4 patients (11%), and 1 (3%) died of pneumonia on the 28th postoperative day. The method we describe is a safe and effective alternative to the current technique of normothermic retrograde continuous cardioplegia and offers both physiologic and technical advantages to patients undergoing cardiac valve procedures.

Contraindications for percutaneous transluminal coronary angioplasty in treatment of unstable angina pectoris.

In recent years, the indications for percutaneous transluminal coronary angioplasty have expanded to include multivessel disease, unstable angina pectoris, stenosis of coronary bypass grafts, and recent total coronary occlusion. To evaluate our experience in using percutaneous transluminal coronary angioplasty to treat unstable angina, we reviewed the records of the patients who underwent this procedure at our hospital between January 1983 and December 1986. Of the 689 patients who underwent balloon angioplasty during the study period, 454 had stable angina and 235 had unstable angina; of the latter group, 34 (14.5%) required emergency coronary artery bypass grafting after balloon angioplasty failed. This outcome was associated with 2 risk factors: previous myocardial infarction and triple-vessel disease. Our data suggest that, in cases of unstable angina pectoris, percutaneous transluminal coronary angioplasty should be reserved for patients with single-vessel disease and no evidence of previous myocardial infarction. They also lend credence to the conclusion that the disease process in unstable angina is different from that in stable angina, and that therapy should be directed towards reducing platelet aggregation and correcting global ischemia, rather than towards balloon angioplasty of "culprit lesions."

Massive chylopericardium after coronary artery bypass surgery.

Massive isolated chylopericardium is a rare postoperative complication of coronary artery bypass surgery. In the following case, massive chylopericardium developed after a coronary artery bypass procedure in which the left internal mammary artery was used for revascularization. The chylopericardium resulted from direct trauma to the thoracic duct during mobilization of the left internal mammary artery to its origin at the subclavian artery. With adequate drainage, the problem was resolved. In cases in which drainage persists, ligation of the thoracic duct may be necessary.

Blunt rupture of both atrioventricular valves.

Younger patients are surviving extensive damage to the heart and supporting structures, often associated with multiple systems injuries. A 23-year-old patient who sustained blunt trauma to the chest resulting in a pericardial laceration, injury to tricuspid and mitral valves, myocardial contusion, and paresis of the left phrenic nerve is reported. Porcine bioprosthetic valve replacement of both atrioventricular valves was necessary. Prompt diagnosis and aggressive intervention of such injuries can lead to successful repair of complex cardiac trauma.

Myocardial revascularization combined with aortic valve replacement.

We reviewed 50 consecutive patients who had undergone complete myocardial revascularization combined with aortic valve replacement during a 5-year interval ending in June 1983. A cold blood cardioplegia technique, utilizing not only the native circulation but also the vein conduits, was used. All patients had greater than 70% stenoses of the major coronary arterial system. No patient had valve replacement alone, and no patient was refused operation. The mean number of arteries grafted was 2.3. There were two hospital deaths. One patient had evidence of perioperative myocardial infarction. There were two late deaths and one non-fatal myocardial infarction during the follow-up period, which averaged 16 months. The technique of hypothermic blood cardioplegia used provides a uniform distribution for myocardial protection, especially in the hypertrophied ventricle, and is superior to previously employed methods. This study indicates that myocardial revascularization combined with aortic valve replacement should be performed in patients with coexisting aortic valvular and coronary disease.

Traumatic aortic insufficiency after blunt chest trauma.

Traumatic aortic insufficiency is an uncommon result of blunt trauma. The typical clinical features include trauma, followed by pain (and often syncope), a musical aortic diastolic murmur, and progressive cardiac decompensation. Shock is an unusual manifestation of traumatic aortic insufficiency. In this report, a patient is described who experienced shock, a widened mediastinum, and failure to respond to fluid resuscitation after cardiac injury in an automobile accident. Emergency surgery was performed and an intimal tear was repaired. A #25 Carpentier-Edwards bioprosthesis was used to replace the aortic valve, which was avulsed from the commissure of the right and left cusps. Since aortic valve replacement offers an excellent prognosis, it should be done at the first signs of cardiac decompensation.

Revascularization of the circumflex coronary artery in the atrioventricular groove.

Complete myocardial revascularization entails the grafting of all vessels of adequate size demonstrating occlusive arteriosclerotic vascular disease. Revascularization of the circumflex coronary artery in the atrioventricular groove has been a major surgical challenge because of the difficulty of exposing it. We discuss here our operative technique in 12 consecutive patients requiring revascularization of that segment of the circumflex coronary artery. Eleven grafts studied in the postoperative period were found to be patent, and the clinical course of the remaining patient and direct observations, including enzyme studies and periodic stress testing, have not shown any evidence of graft failure.

The direct surgical management of lesions of the high internal carotid artery.

The diagnosis and surgical management of non-penetrating high cervical internal carotid injuries continues to be a major problem. The increased incidence of these lesions is due to the escalation of motor vehicular trauma involving multi-system injuries as seen in our Trauma Unit. Carotid angiographic studies are necessary for diagnosis when there is an index of suspicion at time of injury. There have been varied opinions concerning the best treatment due to the difficulty of direct access to the para-mandibular, para-antantoxial segment of the internal carotid artery. Two cases of post-traumatic aneurysms have been discussed and an innovative surgical technique is demonstrated with excellent results. This technique can be utilized in other lesions of the high carotid artery such as intimal flaw and/or dissection of this vessel. The primary indications for surgical intervention are propagation of emboli originating in the aneurysmal sac and intolerance of head noise to the patients (not seen in our patients).