The Archipelago of Fernando de Noronha: An Intriguing Malformed Toad Hotspot in South America

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Causes of death and cardiovascular complications in adolescents and adults with congenitally malformed hearts: an autopsy study of 102 cases

Objectives: To identify the causes of death and main cardiovascular complications in adolescents and adults with congenitally malformed hearts. Design: Retrospective review of 102 necropsy reports from a tertiary centre obtained over a period of 19 years. Methods: The diagnosis, the operated or non-operated state of the main defect, the cause of death, and main complications were related to the age and gender. Other clinically relevant conditions, and identifiable sequels of previous diseases, were also noted. Results: The ages ranged from 15 to 69 years, with a mean of 31.1 and a median of 28 years, with no difference detected according to the gender. Of the patients, two-thirds had been submitted to at least one cardiac surgery. The mean age of death was significantly higher in non-operated patients (p = 0.003). The most prevalent cause of death in the whole group was related to recent surgery, found in one-third. From them, two-fifths corresponded to reoperations. Among the others, cardiac failure was the main terminal cause in another third, and the second cause was pulmonary thromboembolism in just over one-fifth, presenting a significant association with histopathological signs of pulmonary hypertension (p = 0.011). Infection was the cause of death in 7.8% of the patients, all previously operated. Acute infective endocarditis was present or was the indication for the recent surgery in one-tenth of the patients, this cohort having a mean age of 27.8 years. There was a statistically significant association between the occurrence of endocarditis and defects causing low pulmonary blood flow (p = 0.043). Conclusions: Data derived from necropsies of adults with congenital heart defects can help the multidisciplinary team refine both their diagnosis and treatment.

Role of central nitric oxide in behavioral thermoregulation of toads during hypoxia

Nitric oxide (NO) is thought to play a key role in the development of hypoxia-induced anapyrexia in mammals, acting on the preoptic region of the anterior hypothalamus to activate autonomic heat loss responses. Regarding behavioral thermoregulation, no data exists for NO modulation/mediation of thermoregulatory behavior changes during hypoxia. Therefore, we tested the hypothesis that NO is involved in the preferred body temperature (Tb) reduction in the hypoxic toad Chaunus schneideri (formerly Bufo paracnemis), a primarily behavioral thermoregulator. Toads equipped with a temperature probe were placed in a thermal gradient chamber, and preferred Tb was monitored continuously. We analyzed the effect of intracerebroventricular injections of the nonselective NO synthase inhibitor L-NMMA (200, 400 and 800 microg per animal) or mock cerebrospinal fluid (mCSF, vehicle) on the preferred Tb of toads. No significant difference in preferred Tb was observed after L-NMMA treatments. Another group of toads treated with 2 mg kg(-1) (400 microg per animal) of L-NMMA or mCSF was submitted to hypoxia (3% inspired 02) for 8 h. The vehicle group showed a reduction of preferred Tb, a response that was inhibited by L-NMMA. A 3rd group of hypoxic animals was injected with Ringer or L-NMMA (2 mg kg(-1)) into the lymph sac and both treatments induced no change in the anapyretic response to hypoxia. These results indicate that NO acting on the central nervous system has an excitatory role for the development of hypoxia-induced anapyrexia in toads. (C) 2008 Elsevier Inc. All rights reserved.

Inferring population history from microsatellite and enzyme data in serially introduced cane toads, Bufo marinus

Much progress has been made on inferring population history from molecular data. However, complex demographic scenarios have been considered rarely or have proved intractable. The serial introduction of the South-Central American cane Load Bufo marinas in various Caribbean and Pacific islands involves four major phases: a possible genetic admixture during the first introduction, a bottleneck associated with founding, a transitory, population boom, and finally, a demographic stabilization. A large amount of historical and demographic information is available for those introductions and can be combined profitably with molecular data. We used a Bayesian approach to combine this information With microsatellite (10 loci) and enzyme (22 loci) data and used a rejection algorithm to simultaneously estimate the demographic parameters describing the four major phases of the introduction history,. The general historical trends supported by microsatellites and enzymes were similar. However, there was a stronger support for a larger bottleneck at introductions for microsatellites than enzymes and for a more balanced genetic admixture for enzymes than for microsatellites. Verb, little information was obtained from either marker about the transitory population boom observed after each introduction. Possible explanations for differences in resolution of demographic events and discrepancies between results obtained with microsatellites and enzymes were explored. Limits Of Our model and method for the analysis of nonequilibrium populations were discussed.

A review of the oriental toads of the genus Ansonia Stoliczka.

v.39:no.43(1960)

Secondary sex characters of Chinese frogs and toads.

v.22:no.2(1936)

The frogs and toads of the Chicago area / by Karl P. Schmidt, Asst. Curator of Reptiles and Amphibians.

no.11(1929)

Notes on toads of the genus Pelophryne.

v.39:no.39(1960)

A vertebrate reproductive system involving three ploidy levels : hybrid origin of triploids in a contact zone of diploid and tetraploid green toads (Bufo viridis subgroup)

The rise and consequences of polyploidy in vertebrates, whose origin was associated with genome duplications, may be best studied in natural diploid and polyploid populations. In a diploid/tetraploid (2n/4n) geographic contact zone of Palearctic green toads in northern Kyrgyzstan, we examine 4ns and triploids (3n) of unknown genetic composition and origins. Using mitochondrial and nuclear sequence, and nuclear microsatellite markers in 84 individuals, we show that 4n (Bufo pewzowi) are allopolyploids, with a geographically proximate 2n species (B. turanensis) being their maternal ancestor and their paternal ancestor as yet unidentified. Local 3n forms arise through hybridization. Adult 3n mature males (B. turanensis mtDNA) have 2n mothers and 4n fathers, but seem distinguishable by nuclear profiles from partly aneuploid 3n tadpoles (with B. pewzowi mtDNA). These observations suggest multiple pathways to the formation of triploids in the contact zone, involving both reciprocal origins. To explain the phenomena in the system, we favor a hypothesis where 3n males (with B. turanensis mtDNA) backcross with 4n and 2n females. Together with previous studies of a separately evolved, sexually reproducing 3n lineage, these observations reveal complex reproductive interactions among toads of different ploidy levels and multiple pathways to the evolution of polyploid lineages.