Population Dynamics Modeling of Arapaima gigas

Pirarucu (Arapaima gigas) has been of the most important natural fishing resources of the Amazon region. Due to its economic importance, and the necessity to preserve the species hand, field research concerning the habits and behavior of the pirarucu has been increasing for the last 20 years. The aim of this paper is to present a mathematical model for the pirarucu population dynamics considering the species peculiarities, particularly the male parental care over the offspring. The solution of the dynamical systems indicates three possible equilibrium points for the population. The first corresponds to extinction; the third corresponds to a stable population close to the environmental carrying capacity. The second corresponds to an unstable equilibrium located between extinction and full use of the carrying capacity. It is shown that lack of males’ parental care closes the gap between the point corresponding to the unstable equilibrium and the point of stable non-trivial equilibrium. If guarding failure reaches a critical point the two points coincide and the population tends irreversibly to extinction. If some event tends to destabilize the population equilibrium, as for instance inadequate parental care, the model responds in such a way as to restore the trajectory towards the stable equilibrium point avoiding the route to extinction. The parameters introduced to solve the system of equations are partially derived from limited but reliable field data collected at the Mamirauá Sustainable Development Reserve (MSDR) in the Brazilian Amazonian Region.

A new combination in Peristethium (Loranthaceae) expands the genus' range into the Amazon-Cerrado ecotone

The genus Peristethium, characterized by determinate inflorescences protected by deciduous bracts, occurs in the northwest of South America, as well as Costa Rica and Panama. The main objective of this paper was to transfer one species to what we believe is its correct generic placement in Peristethium, that likewise implies in a shift of the genus' distribution beyond the Amazon. A new combination, Peristethium reticulatum, is proposed, based on Struthanthus reticulatus, described from Tocantins in 1980. The sexual dimorphism of the inflorescences of P. reticulatum (sessile male flowers and pedicellate female flowers) associated with male inflorescences that are inserted at leafless nodes are unique within the genus. The male flowers have dimorphic stamens, well-developed anthers and a pistiloid, whilst female flowers have robust styles and stigmas, and much reduced staminodes. Peristethium reticulatum and P. polystachyum occurs in the Amazon regions of Brazil, with the former recorded also in the ecotone with the Central Brazilian savannas (Cerrados).

Right coronary artery fistula with congestive heart failure in the neonate. Doppler echocardiographic diagnosis and closure with detachable balloon

We report here a case of coronary artery fistula in a neonate with clinical signs of heart failure. The electrocardiogram showed signs of left ventricular hypertrophy and diffuse alterations in ventricular repolarization. Chest X-ray showed an enlargement of the cardiac silhouette with an increase in pulmonary flow. After echocardiographic diagnosis and angiographic confirmation, closure of the fistulous trajectory was performed with a detachable balloon with an early and late successful outcome.

Safety and efficacy of angioplasty with intracoronary stenting in patients with unstable coronary syndromes. Comparison with stable coronary syndromes

OBJECTIVE: To assess safety and efficacy of coronary angioplasty with stent implantation in unstable coronary syndromes. METHODS: Retrospective analysis of in-hospital and late evolution of 74 patients with unstable coronary syndromes (unstable angina or infarction without elevation of the ST segment) undergoing coronary angioplasty with stent placement. These 74 patients were compared with 31 patients with stable coronary syndromes (stable angina or stable silent ischemia) undergoing the same procedure. RESULTS: No death and no need for revascularization of the culprit artery occurred in the in-hospital phase. The incidences of acute non-Q-wave myocardial infarction were 1.4% and 3.2% (p=0.6) in the unstable and stable coronary syndrome groups, respectively. In the late follow-up (11.2±7.5 months), the incidences of these events combined were 5.7% in the unstable coronary syndrome group and 6.9% (p=0.8) in the stable coronary syndrome group. In the multivariate analysis, the only variable with a tendency to significance as an event predictor was diabetes mellitus (p=0.07; OR=5.2; 95% CI=0.9-29.9). CONCLUSION: The in-hospital and late evolutions of patients with unstable coronary syndrome undergoing angioplasty with intracoronary stent implantation are similar to those of the stable coronary syndrome group, suggesting that this procedure is safe and efficacious when performed in unstable coronary syndrome patients.

Use of transesophageal echocardiography during implantation of aortic endoprosthesis (stent). Initial experience

OBJECTIVE: To report the role played by transesophageal echocardiography during implantation of self-expanding aortic endoprostheses (stent) at a hemodynamics laboratory. METHODS: Thirteen patients underwent stent implantation in the descending thoracic aorta with the aid of transesophageal echocardiography during the entire procedure. Indications for stenting were as follows: 8 aortic dissections, 2 true aneurysms, 2 penetrating atherosclerotic ulcers, and 1 traumatic pseudoaneurysm. RESULTS: No complications resulting from the use of transesophageal echocardiography were observed. In 12 patients, the initial result was considered appropriate, with total or partial resolution of the major lesion confirmed by a posterior examination. In 1 patient, the procedure was suspended after transesophageal echocardiography and angiography showed that the proximal aortic diameter was inappropriate. Transesophageal echocardiography contributed to clarifying relevant points, such as aortic diameter, anatomic detail of the intimal lesion, and location and size of the communicating orifice. In addition, it facilitated placing the stent in the target lesion, reduced the time of exposure to radiation and the use of contrast medium, and provided rapid identification of intercurrent events, possibly reducing the total duration of the procedure. CONCLUSION: The use of transesophageal echocardiography during placement of aortic stents seems appropriate. The actual advantages of the procedure will be defined in a comparative prospective study.

Assessment of Thromboembolism After the Cox-Maze Procedure for Chronic Atrial Fibrillation Secondary to Mitral Valve Lesion

OBJECTIVE: To assess the occurrence of late thromboembolism after surgical repair of chronic atrial fibrillation (AF) simultaneously with repair of mitral valve using the Cox-Maze procedure. METHODS: 69 patients underwent Cox 3 procedure, with no cryoablation simultaneously with mitral valvuloplasty or prosthesis. Mean age was 49.9±13.2 years. Mean follow-up was of 31.7±19 months. Types of lesion were as follows: 33 (48%) stenoses, 23 (33%) insufficiencies, and 13 (19%) double lesions. Procedures were: 64 (93%) valvuloplasties, 3 (4%) biological and 2 (3%) mechanical prosthesis placement. There were 9 (13%) patients with previous systemic embolism and 2 (3%) had left atrial thrombi. RESULTS: Early mortality was 7% and late 1%. 2 patients (3%) were reoperated for mitral placement. At last evaluation, 10 patients (15%), were in AF. The remaining 59 (85%) were either in sinus / atrial rythm (74%) or under pacing (12%). There were no occurrence of early or late, systemic or pulmonary embolism. Permanent anticoagulation was employed in 16 cases, 10 in regular rythm and 6 in AF. The remaining 47 (75%), 2 in AF and 45 in regular rythm, did not receive anticoagulants. CONCLUSIONS: These results are in accordance with others series, where the occurrence of embolism was rare after maze procedure. Permanent systemic anticoagulation seems to be unnecessary in those cases.

Percutaneous Stent Implantation for Treating Multivessel Coronary Disease in Patients with and without Involvement of the Proximal Segment of the Anterior Descending Coronary Artery

OBJECTIVE: To assess coronary stent placement in patients with multivessel coronary disease and involvement of the proximal portion of the anterior descending coronary artery. METHODS: We retrospectively analyzed the in-hospital and late evolution of 189 patients with multivessel coronary disease, who underwent percutaneous coronary stent placement. These patients were divided into 2 groups as follows: group I (GI) - 59 patients with involvement of the proximal segment of the anterior descending coronary artery; and group II (GII) - 130 patients without involvement of the proximal segment of the anterior descending coronary artery. RESULTS: No significant difference was observed in the success rate of the procedure (91.5% versus 97.6%, p=0.86), nor in the occurrence of major adverse cardiac events (5.1% versus 1.5%, p=0.38), nor in the occurrence of major vascular complications (1.7% versus 0%, p=0.69) in the in-hospital phase. In the late follow-up, the incidence of major adverse cardiac events (15.4% versus 13.7%, p=0.73) and the need for new revascularization (13.5% versus 10.3%, p=0.71) were similar for both groups. CONCLUSION: The in-hospital and late evolution of patients with multivessel coronary disease with and without involvement of the proximal segment of the anterior descending coronary artery treated with coronary stent placement did not differ. This suggests that this revascularization method is an effective procedure and a valuable option for treating these types of patients.

Percutaneous implantation of endoprostheses in the carotid arteries

OBJECTIVE: To assess the in-hospital evolution of patients undergoing percutaneous stent placement in the carotid arteries. METHODS: From August 1996 to April 2001, we studied 86 patients with carotid arterial obliterative lesions > 70% who were treated with percutaneous stent placement in the carotid arteries. We assessed the rate of success of the implantation and of the procedure, the types of stents used, mortality rate, and neurological complications. RESULTS: Successful implantation was obtained in 98.9% of the cases, and the procedure was successful in 91.8%. The Wallstent was the most frequently used stent (73 patients - 77%). Cerebral strokes occurred as follows: 3 (3.2%) transient ischemic attacks, 1 (1.1%) minor stroke, and 3 (3.1%) major strokes. One (1.1%) patient died during hospitalization. CONCLUSION: The high rate of success of stent implantation (98.9%) in addition to the low rate of cerebral stroke/death (4.2%) showed the efficiency and safety of percutaneous stent placement in carotid arteries.

Surgical myocardial revascularization without extracorporeal circulation

OBJECTIVE: To assess the immediate postoperative period of patients undergoing myocardial revascularization without extracorporeal circulation with different types of grafts. METHODS: One hundred and twelve patients, 89 (79.5%) of whom were males, were revascularized without extracorporeal circulation. Their ages ranged from 39 to 85 years. The criteria for indicating myocardial revascularization without extracorporeal circulation were as follows: revascularized coronary artery caliber > 1.5 mm, lack of intramyocardial trajectory on coronary angiography, noncalcified coronary arteries, and tolerance of the heart to the different rotation maneuvers. RESULTS: Myocardial revascularization without extracorporeal circulation was performed in 112 patients. Three were converted to extracorporeal circulation, which required a longer hospital stay but did not impact mortality. During the procedure, the following events were observed: atrial fibrillation in 10 patients, ventricular fibrillation in 4, total transient atrioventricular block in 2, ventricular extrasystoles in 58, use of a device to retrieve red blood cells in 53, blood transfusion in 8, and arterial hypotension in 89 patients. Coronary angiography was performed in 20 patients on the seventh postoperative day when the grafts were patent. CONCLUSION: Myocardial revascularization without extracorporeal circulation is a reproducible technique that is an alternative for treating ischemic heart disease.

Increasing the efficiency of utilization of soil and fertilizer phosphorus in the subtropical and tropical agricultural systems C

As a rule, soils of the subtropical and tropical regions, in which rainfall is not limiting, are acidic, and low in phosphorus, and, to a less extent, in other macro and micronutrients as well, such a sulfur, boron and zinc. The establishment of a permanent agricultural prac. tice therefore, demands relatively high usage of liming and phosphatic fertilization, to begin with. Several approaches, not mutually exclusive, could be used in order to increase the efficiency of utilization of soil and fertilizer phosphorus so that, goal of diminishing costs of production is reached. The use of liming materials bringing up pH to 6.0-6.5 causes the conversion of iron and aluminum phosphates to more available calcium phosphates; on the other hand, by raising calcium saturation in the exchange complex, it improves the development and operation if the root system which allows c or a higher utilization of all soil nutrients, including phosphorus, and helps of stand water deficits which may occur. The role of mycorrhizal fungi should be considered as a way of increasing soil and fertilizer P utilization, as well as the limitations thereof. Screening of and breeding for varieties with higher efficiency of uptake and utilization of soil and fertilizer phosphorus leads to a reduction in cost of inputs and to higher benefit/cost ratios. Corrective fertilization using ground rock phosphate helps to saturate the fixation power of the soil thereby reducing, as a consequence, the need for phosphorus in the maintenance fertilization. Maintenance fertilization, in which soluble phos-phatic sources are used, could be improved by several means whose performance has been proved: limimg, granula tion, placement, use of magnesium salts. Last, cost of phosphate fertilization could be further reduced, without impairing yields, through impairing yields, through changes in technology designed to obtain products better adapted to local conditions and to the availability or raw materials and energy sources.

The Adolpho Lutz collection of Tabanidae: (Diptera): I. The described genera and species, condition of the collection, and selection of lectotypes

A study of the Adolpho Lutz Collection of Tabanidae at the Instituto Oswaldo Cruz and of additional Lutz material at the Instituto Butantan in São Paulo is reported. Of the ninety-four species of Tabanidae validly described by Lutz, type material of eighty-four was recognized, either holotypes, allotypes or syntypes. Lectotypes were selected from among syntype series or remaining specimens and all type material was labelled. Of the ten species of which no type material could be found, neotypes were designated in the case of two species, Erephosis nigricans and Erephosis pseudo-aurimaculata. Types of three species, Chrysops ecuadoriensis, Dichelacera salvadorensis and Esenbeckia nigricorpus are believed to have been in Hamburg and destroyed during the last war. Types of two species, Esenbeckia biscutellata and E. dubia, and additional type material of several others are believed to have been in Montevideo. A request for information about them remains unanswered. Types of the remaining three species, Dichelacera intermedia, Dichelacera laceriascia and Esenbeckia distinguenda could not be found, and it is believed that at least the type of the last species was accidentally destroyed. Three specific of subspecific names proposed by Lutz but palaced by others in synonymy have been revalidated, Acanthocera intermedia, Erephosis brevistria and Esenbeckia fenestrata. Generic placement of two names has been changed, Esenbeckia arcuata ricardoae to Proboscoides, and Selasoma giganteum to Stibasoma. Seven specific names proposed by Lutz appear to be synonyms of earlier names, as follows: Bombylopsis juxtaleonina Lutz and Castro, 1936 = B. leonina Lutz, 1909. Bombylopsis pseudoanalis Lutz, 1909 = B. erythronotata (Bigot, 1892). Esenbeckia fuscipennis var. flavescens Lutz, 1909 = Esenbeckia fuscipennis Wied., 1828. Fidena chrysopyga Lutz and Castro, 1936 = F. atra Lutz and Castro, 1936. Laphriomyia longipalpis Lutz and Castro, 1937 = L. mirabilis Lutz, 1911. Stibasoma semiflavum Lutz, 1915 = St. bicolor Bigot, 1892. Tabanus hesperus Lutz, 1912 = Chlorotabanus (Cryptolylus) innotescens (Walker, 1854). Four Lutz names appear to antedate names proposed by others, viz.: Diachlorus angustifrons Kröber, 1930 and D. ochraceus Kröb., 1928 not Macquart, 1850 = Diachlorus fuscistigma Lutz, 1913. Psalidia fairchildi Barretto, 1950 = dicladocera conspicua Lutz and Neiva, 1914. Fidena pseudo-fulvithorax Kröb., 1931 = Erephopsis flavicrinis Lutz, 1909. Esenbeckia lemniscata Enderlein, 1925 = Esenbeckia clari Lutz, 1909. Some comments on Lutz' system of classification are given together with notes on the genotypes and included species of his genera as revaled by his collection and notes.

Wyeomyia luteoventralis Theobald, the type species of the subgenus Dendromyia Theobald (Diptera: Culicidae)

Wyeomyia (Dendromyia) luteoventralis is redescribed from females, males, larvae and pupae collected at the type locality, in Brazil, and compared to the closely related species. At least six species - Wy. luteoventralis, Wy. ypsipola, Wy. testei, Wy. trifurcata, Wy. complosa and Wy. jocosa - appparently, belong to a monophyletic group, the subgenus Dendromyia. All other species previously included in Dendromyia are hereby excluded from this subgenus and retained in genus Wyeomyia without subgeneric placement.

Patterns of tuberculosis in the Americas: how can modern biomedicine inform the ancient past?

Tuberculosis (TB) is an infectious disease that continues to take its toll on human lives. Paleopathological research indicates that it has been a significant cause of death among humans for at least five thousand years. Because of the devastating consequences to human health, social systems, and endangered primate species, TB has been the subject of many and varied research efforts throughout the world, efforts that are amassing an enormous amount of data concerning the causative agent Mycobacterium tuberculosis. Despite sequencing of the M. tuberculosis genome and numerous molecular epidemiological studies, many questions remain regarding the origin, evolution, and future co-evolutionary trajectory of M. tuberculosis and humans. Indeed, the origin of pre-Columbian New World TB has been and remains hotly debated, and resolution of this controversy will likely only come with integration of data and theory from multiple disciplines. In this paper, we discuss the pre-Columbian TB controversy, and then use research from biological and biomedical sciences to help inform paleopathological and archaeological studies of this ubiquitous disease that plagued our ancient forbears.