The international implications of the Chinese model of development in the Global South: Asian Consensus as a network power

This paper analyzes People's Republic of China (PRC) economic and political ascendance in the 21st century focusing on the evolution of the sui generis economic development model and its significances of the evolution of relationship between China and the developing countries in the peripheral "Global South." The objective of this article is to analyze the relationship between China and the Global South (Africa and South America) in the 21st century, characterized as a new Center-periphery global network power based on trade and investment that we call as "Asian Consensus."

A model of destination competitiveness/sustainability: Brazilian perspectives

This paper reviews the understanding I have gained from several years of research, and from several more years of ongoing discussions with industry leaders regarding the nature of competitiveness among tourism destinations. This understanding has been captured, in summary form, in the model of Destination Competitiveness/Sustainability (Ritchie and Crouch, 2003). This model contains seven (7) components which we have found to play a major role, from a policy perspective, in determining the competitiveness/sustainability of a tourism destination. In addition to the valuable understanding which these seven components provide from a policy perspective, the specific elements of each the major components provide a more useful/practical guidance to those who are responsible for the ongoing management of a DMO (Destination Management Organization). With this overview in mind, this paper will provide a detailed review and explanation of the model that I have developed with colleague, Dr. Geoffrey I. Crouch of Latrobe University in Melbourne, Australia. Based on previous presentations throughout the world, it has proven very helpful to both academics and practitioners who seek to understand the complex nature of tourism destination competitiveness/sustainability.

Studies on mosquitoes (Diptera: Culicidae) and anthropic environment: 6 - Breeding in empty conditions of rice fields in South-Eastern Brazil

Studies on culicid breeding in empty rice fields were carried out during the cultivation cycle from May to November 1993. This period corresponded to stages 1 and 2, when empty conditions prevailed. Breeding occurred in stage 1 and the first part of stage 2, corresponding respectively to fallow uncultivated and ploughing situations. No breeding was found to take place during the second part of stage 2 when transient floods and harrowing occurred. The predominant species were Aedes scapularis, Culex nigripalpus and Cx. mollis. The Pilosus Group of Culex (Melanoconion) was found at lower densities. Some epidemiological considerations are presented.

A theoretical model of the evolution of virulence in sexually transmitted HIV/AIDS

INTRODUCTION: The evolution of virulence in host-parasite relationships has been the subject of several publications. In the case of HIV virulence, some authors suggest that the evolution of HIV virulence correlates with the rate of acquisition of new sexual partners. In contrast some other authors argue that the level of HIV virulence is independent of the sexual activity of the host population. METHODS: Provide a mathematical model for the study of the potential influence of human sexual behaviour on the evolution of virulence of HIV is provided. RESULTS: The results indicated that, when the probability of acquisition of infection is a function both of the sexual activity and of the virulence level of HIV strains, the evolution of HIV virulence correlates positively with the rate of acquisition of new sexual partners. CONCLUSION: It is concluded that in the case of a host population with a low (high) rate of exchange of sexual partners the evolution of HIV virulence is such that the less (more) virulent strain prevails.

Prevention of electrocardiographic and histopathologic alterations in the murine model of Chagas' disease by preinoculation of an attenuated Trypanosoma cruzi strain

The effects of infection with Trypanosoma cruzi on the electrocardiographic tracings of mice were studied in 4.groups of animals: (1) normal; (2) infected with a pathogenic T. cruzi strain (TS COB); (3) immunized with 3 intraperitoneal inocula of 10(6) attenuated T. cruzi epimastigotes (TCC) and (4) immunized-infected, which sequentially received the treatments of groups 3 and 2. Infection and protection were confirmed by xenodiagnosis and histopathology. Isolated alterations such as extrasystolia, 1st degree atrioventricular block, arrhythmia and ST elevation were observed in normal as well as infected mice. However, tracings taken repeatedly on each mouse over a 293 day period revealed a set of alterations which were more frequently seen in infected (14/22) than in normal (4/27) animals (p = 0.00048). These alterations consisted of supraventricular tachycardia, sinus bradycardia and persisting, first degree AV blocks, often associated to pacemaker changes. Inoculation of attenuated T. cruzi (group 3) did not increase these alterations (2/27 mice) but significantly prevented their development after challenge with the pathogenic strain (1/19 versus 14/22 mice, p = 0.000095). Thus, preimmunization reduced not only parasitemia but also a pathogenic consequence of T. cruzi infection. This evidence is relevant for immunoprevention studies against Chagas' disease.

Activity of two different triazoles in a murine model of paracoccidioidomycosis

A new orally absorbable triazole (Schering 39304) with a long serum half-life in man (60 hours), was tried in a murine model of progressive paracoccidioidomycosis and compared with itraconazole, another triazole which has proven effective in this mycosis. Only 15% of the infected, untreated mice survived while 53 to 75% of the animals receiving itraconazole survived. Mice treated with Schering 39304 exhibited higher (86 - 100%) survival rates. Statistically, the 5 mg/kg Sch 39304 was superior to the 50 mg/kg itraconazole dose. Lung cultures showed that 20 mg/kg/day of Sch achieved sterilization of the infectious foci. These results indicate that the new triazole will have a place in the treatment of paracoccidioidomycosis

Gastric acid secretion response in the Cebus apella: a monkey model of chronic Chagas disease

The objective was to study the secretory pattern, both basal and stimulated either by histamine (0.1 mg/kg) or pentagastrin (64 ug/kg) in eighteen Cebus apella monkeys chronically infected with different T. cruzi strains (CA1, n=10; Colombian, n=4 and Tulahuen, n=4) and to describe the morphological findings in the gastrointestinal tract in twelve infected (6 sacrificed and 6 spontaneously dead) and four healthy monkeys. All infected monkeys and 35 healthy ones were evaluated by contrast X-ray examination. No differences were observed in basal acid output between control and infected groups. Animals infected with the Tulahuen and Colombian strains showed significant lower values of peak acid output in response to histamine or pentagastrin (p<0.01 and p<0.05 respectively; "t" test) in comparison to the controls. Barium contrast studies showed enlargement and dilatation of the colon in three infected animals. Histopathological lesions were seen in 75% of the autopsied animals either in colon alone (33%) or both, in colon and esophagus (42%). The normal secretion observed in the CA1 infected group could be due to a lower virulence of the strain, a lower esophagic tropism or the necessity of a longer post-infection time to cause lesions.

Flucytosine + fluconazole association in the treatment of a murine experimental model of cryptococcosis

The efficacy of flucytosine (5-FC) and fluconazole (FLU) association in the treatment of a murine experimental model of cryptococcosis, was evaluated. Seven groups of 10 Balb C mice each, were intraperitoneally inoculated with 10(7) cells of Cryptococcus neoformans. Six groups were allocated to receive 5-FC (300 mg/kg) and FLU (16 mg/ kg), either combined and individually, by daily gavage beginning 5 days after the infection, for 2 and 4 weeks. One group received distilled water and was used as control. The evaluation of treatments was based on: survival time; macroscopic examination of brain, lungs, liver and spleen at autopsy; presence of capsulated yeasts in microscopic examination of wet preparations of these organs and cultures of brain homogenate. 5-FC and FLU, individually or combined, significantly prolonged the survival time of the treated animals with respect to the control group (p<0.01). Animals treated for 4 weeks survived significantly longer than those treated for 2 weeks (p<0.01). No significant differences between the animals treated with 5-FC and FLU combined or separately were observed in the survival time and morphological parameters. The association of 5-FC and FLU does not seem to be more effective than 5-FC or FLU alone, in the treatment of this experimental model of cryptococcosis.

DOSE RESPONSE EFFECT OF Paracoccidioides brasiliensis IN AN EXPERIMENTAL MODEL OF ARTHRITIS

Paracoccidioidomycosis (PCM) is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb) and corresponds to prevalent systemic mycosis in Latin America. The aim of the present work was to evaluate the dose response effect of the fungal yeast phase for the standardization of an experimental model of septic arthritis. The experiments were performed with groups of 14 rats that received doses of 103, 104 or 105 P. brasiliensis (Pb18) cells. The fungi were injected in 50 µL of phosphate-buffered saline (PBS) directly into the knee joints of the animals. The following parameters were analyzed in this work: the formation of swelling in knees infused with yeast cells and the radiological and anatomopathological alterations, besides antibody titer by ELISA. After 15 days of infection, signs of inflammation were evident. At 45 days, some features of damage and necrosis were observed in the articular cartilage. The systemic dissemination of the fungus was observed in 11% of the inoculated animals, and it was concluded that the experimental model is able to mimic articular PCM in humans and that the dose of 105 yeast cells can be used as standard in this model.

Heart hypoplasia in an animal model of congenital diaphragmatic hernia

PURPOSE: In previous papers, we described a new experimental model of congenital diaphragmatic hernia in rabbits, and we also reported noninvasive therapeutic strategies for prevention of the functional and structural immaturity of the lungs associated with this defect. In addition to lung hypoplasia, pulmonary hypertension, biochemical, and structural immaturity of the lungs, the hemodynamics of infants and animals with congenital diaphragmatic hernia are markedly altered. Hence, cardiac hypoplasia has been implicated as a possible cause of death in patients with congenital diaphragmatic hernia, and it is hypothesized to be a probable consequence of fetal mediastinal compression by the herniated viscera. Cardiac hypoplasia has also been reported in lamb and rat models of congenital diaphragmatic hernia. The purpose of the present experiment was to verify the occurrence of heart hypoplasia in our new model of surgically produced congenital diaphragmatic hernia in fetal rabbits. METHODS: Twelve pregnant New Zealand rabbits underwent surgery on gestational day 24 or 25 (normal full gestational time - 31 to 32 days) to create left-sided diaphragmatic hernias in 1 or 2 fetuses per each doe. On gestational day 30, all does again underwent surgery, and the delivered fetuses were weighed and divided into 2 groups: control (non-surgically treated fetuses) (n = 12) and congenital diaphragmatic hernia (n = 9). The hearts were collected, weighed, and submitted for histologic and histomorphometric studies. RESULTS: During necropsy, it was noted that in all congenital diaphragmatic hernia fetuses, the left lobe of the liver herniated throughout the surgically created defect and occupied the left side of the thorax, with the deviation of the heart to the right side, compressing the left lung; consequently, this lung was smaller than the right one. The body weights of the animals were not altered by congenital diaphragmatic hernia, but heart weights were decreased in comparison to control fetuses. The histomorphometric analysis demonstrated that congenital diaphragmatic hernia promoted a significant decrease in the ventricular wall thickness and an increase in the interventricular septum thickness. CONCLUSION: Heart hypoplasia occurs in a rabbit experimental model of congenital diaphragmatic hernia. This model may be utilized for investigations in therapeutic strategies that aim towards the prevention or the treatment of heart hypoplasia caused by congenital diaphragmatic hernia.

Low coronary perfusion pressure is associated with endocardial fibrosis in a rat model of volume overload cardiac hypertrophy

Left ventricular hypertrophy following volume overload is regarded as an example of cardiac remodeling without increased fibrosis accumulation. However, infarction is associated with increased fibrosis within the noninfarcted, hypertrophied myocardium, particularly in the subendocardial regions. It is conceivable to suppose that, as also occurs postinfarction, low coronary driving pressure may also interfere with accumulation of myocardial fibrosis following aortocaval fistula. PURPOSE: To investigate the role of acute hemodynamic changes in subsequent deposition of cardiac fibrosis in response to aortocaval fistula. METHOD: Aortocaval fistula were created in 4 groups of Wistar rats that were followed over 4 and 8 weeks: aortocaval fistula 4 and aortocaval fistula 8 (10 rats each) and their respective controls (sham-operated controls - Sh), Sh4 and Sh8 (8 rats each). Hemodynamic measurements were performed 1 week after surgery. Hypertrophy and fibrosis were quantified by myocyte diameter and collagen volume fraction at the end of follow up. RESULT: Compared with Sh4 and Sh8, pulse pressure, left ventricular end-diastolic pressure, and +dP/dt were higher in aortocaval fistula 4 and aortocaval fistula 8, but -dP/dt was similar. Coronary driving pressure (mm Hg), used as an estimate of perfusion pressure, was lower in aortocaval fistula 8 (52.6 ± 4.1) than in Sh8 (100.8 ± 1.3), but comparable between aortocaval fistula 4 (50.0 ± 8.9) and Sh4 (84.8 ± 2.3). Myocyte diameter was greater in aortocaval fistula 8, whereas interstitial and subendocardial fibrosis were greater in aortocaval fistula 4 and aortocaval fistula 8. Coronary driving pressure correlated inversely and independently with subendocardial fibrosis (r² = .86, P <.001), whereas left ventricular systolic pressure (r² = 0.73, P = .004) and end-diastolic pressure (r² = 0.55, P = 012) correlated positively and independently with interstitial fibrosis. CONCLUSION: Coronary driving pressure falls and ventricular pressures increase early after aortocaval fistula and are associated with subsequent myocardial fibrosis deposition.

Chemical and physical attributes and calcium, magnesium, potassium, and phosphorus in the soil of murundu fields in Brazil

Fields of murundus (FM) are wetlands that provide numerous ecosystem services. The objectives of this study were to evaluate the chemical [organic carbon (OC), P, K+, Ca2+, Mg2+, Al3+ and H+Al] and physical [texture and bulk density (Bd)] soil attributes and calculate the organic matter (OM) and nutrient stock (P, Ca, Mg, and K) in soils of FM located in the Guapore River basin in Mato Grosso. Thirty-six sampling points were selected, and soil samples were collected from two environments: the murundu and plain area surrounding (PAS). At each sampling point, mini trenches of 0.5 × 0.5 × 0.4 m were opened and disturbed and undisturbed soil samples were collected at depths of 0-0.1, 0.1-0.2, and 0.2-0.4 m. In the Principal Component Analysis the variables H+Al (49%) and OM (4%) were associated with the F1 component and sand content (47%) with the F2 component. The FM had lower pH values and higher concentrations of K+, P, and H+Al than PAS at all depths (p < 0.05). Additionally, FM stocked up to 433, 360, 205, and 11 kg ha-1 of Ca, Mg, K, and P, respectively, for up to a depth of 0.2 m. The murundu stored two times more K and three times more P than that in the PAS. Our results show that the FM has high sand content and Bd greater than 1.5 Mg m-3, high acidity, low OC content, and low nutrient concentrations. Thus, special care must be taken to preserve FM such that human intervention does not trigger environmental imbalances.

Experimental Model of Gene Transfection in Healthy Canine Myocardium: Perspectives of Gene Therapy for Ischemic Heart Disease

OBJECTIVE: To assess the transfection of the gene that encodes green fluorescent protein (GFP) through direct intramyocardial injection. METHODS: The pREGFP plasmid vector was used. The EGFP gene was inserted downstream from the constitutive promoter of the Rous sarcoma virus. Five male dogs were used (mean weight 13.5 kg), in which 0.5 mL of saline solution (n=1) or 0.5 mL of plasmid solution containing 0.5 µg of pREGFP/dog (n=4) were injected into the myocardium of the left ventricular lateral wall. The dogs were euthanized 1 week later, and cardiac biopsies were obtained. RESULTS: Fluorescence microscopy showed differences between the cells transfected and not transfected with pREGFP plasmid. Mild fluorescence was observed in the cardiac fibers that received saline solution; however, the myocardial cells transfected with pREGFP had overt EGFP expression. CONCLUSION: Transfection with the EGFP gene in healthy canine myocardium was effective. The reproduction of this efficacy using vascular endothelial growth factor (VEGF) instead of EGFP aims at developing gene therapy for ischemic heart disease.

Electrical Properties of Isolated Cardiomyocytes in a Rat Model of Thiamine Deficiency

In modern society, thiamine deficiency (TD) remains an important medical condition linked to altered cardiac function. There have been contradictory reports about the impact of TD on heart physiology, especially in the context of cardiac excitability. In order to address this particular question, we used a TD rat model and patch-clamp technique to investigate the electrical properties of isolated cardiomyocytes from epicardium and endocardium. Neither cell type showed substantial differences on the action potential waveform and transient outward potassium current. Based on our results we can conclude that TD does not induce major electrical remodeling in isolated cardiac myocytes in either endocardium or epicardium cells.

High-fat Diet Promotes Cardiac Remodeling in an Experimental Model of Obesity

AbstractBackground:Although nutritional, metabolic and cardiovascular abnormalities are commonly seen in experimental studies of obesity, it is uncertain whether these effects result from the treatment or from body adiposity.Objective:To evaluate the influence of treatment and body composition on metabolic and cardiovascular aspects in rats receiving high saturated fat diet.Methods:Sixteen Wistar rats were used, distributed into two groups, the control (C) group, treated with isocaloric diet (2.93 kcal/g) and an obese (OB) group, treated with high-fat diet (3.64 kcal/g). The study period was 20 weeks. Analyses of nutritional behavior, body composition, glycemia, cholesterolemia, lipemia, systolic arterial pressure, echocardiography, and cardiac histology were performed.Results:High-fat diet associates with manifestations of obesity, accompanied by changes in glycemia, cardiomyocyte hypertrophy, and myocardial interstitial fibrosis. After adjusting for adiposity, the metabolic effects were normalized, whereas differences in morphometric changes between groups were maintained.Conclusion:It was concluded that adiposity body composition has a stronger association with metabolic disturbances in obese rodents, whereas the high-fat dietary intervention is found to be more related to cardiac morphological changes in experimental models of diet-induced obesity.