Creation of forest edges has a global impact on forest vertebrates.

Forest edges influence more than half of the world's forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1,673 vertebrate species. We show that the abundances of 85% of species are affected, either positively or negatively, by forest edges. Species that live in the centre of the forest (forest core), that were more likely to be listed as threatened by the International Union for Conservation of Nature (IUCN), reached peak abundances only at sites farther than 200-400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest-core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale.

What is the impact of surgical site infection on graft function in kidney transplant recipients?

The impact of surgical site infections (SSIs) on graft function in kidney transplant recipients is controversial. We conducted a matched case-control study (1:1 ratio) between April 2001 and December 2004 in a Brazilian cohort of kidney transplant recipients. The epidemiological and clinical characteristics of SSIs were described based on chart review. The impact on graft function was assessed by comparing serum creatinine measurements and creatinine clearance up to 18 months after transplantation with analysis of variance model. Among 1939 kidney transplants, 120 patients with 145 SSIs were enrolled. Most wound infections were superficial (73.1%). The mortality rate was 0.8%. No impact on graft function was detected. In conclusion, accurate identification of SSIs may have resulted in shorter hospitalization periods, but they had no impact on graft function up to 18 months post transplantation.

Sensations and reaction times evoked by electrical sinusoidal stimulation.

OBJECTIVE: To determine whether 5 Hz and 2000 Hz sinusoidal electric currents evoke different sensations and to indirectly evaluate which peripheral nerve fibers are stimulated by these different frequencies. METHODS: One hundred and fifty subjects chose three among eight descriptors of sensations evoked by 5 Hz and 2000 Hz currents and the results were submitted to factor analysis. In 20 subjects, reaction times to 5, 250 and 2000 Hz currents were determined at 1.1 x ST and reaction times to 5 Hz currents were also determined at 2 x ST. RESULTS: Responses were grouped in four factors: Factor 1, which loaded mainly in descriptors related to tweezers stimulation, was higher than the other factors during 2000 Hz stimulation at 1.5 x ST. Factor 2, which loaded mainly in descriptors related to needle stimulation, was higher than the other factors during 5 Hz stimulation. Factor 1 increased and Factor 2 decreased with an increase in 5 Hz intensity from 1.5 to 4x ST. Reaction times measured from the fastest responses were significantly different: 0.57 s (0.16 to 1.60), 0.34 s (0.12 to 0.71) and 0.22s (0.08 to 0.35) for 5, 250 and 2000 Hz, respectively, and 0.22s (0.11 to 0.34) for 5 Hz at 2 x ST. CONCLUSIONS: Sinusoidal electrical stimulation of 5 Hz and 2000 Hz evoke different sensations. At juxta-threshold intensities, RT measurements suggest that 2000 Hz stimulates Abeta-fibers, 250 Hz Abeta- or A partial differential-fibers, 5 Hz Abeta-, A partial differential- or C-fibers. The fiber type, which was initially stimulated by the lower frequencies, depended on inter-individual differences.

Quantifying the biodiversity value of tropical primary, secondary, and plantation forests.

Biodiversity loss from deforestation may be partly offset by the expansion of secondary forests and plantation forestry in the tropics. However, our current knowledge of the value of these habitats for biodiversity conservation is limited to very few taxa, and many studies are severely confounded by methodological shortcomings. We examined the conservation value of tropical primary, secondary, and plantation forests for 15 taxonomic groups using a robust and replicated sample design that minimized edge effects. Different taxa varied markedly in their response to patterns of land use in terms of species richness and the percentage of species restricted to primary forest (varying from 5% to 57%), yet almost all between-forest comparisons showed marked differences in community structure and composition. Cross-taxon congruence in response patterns was very weak when evaluated using abundance or species richness data, but much stronger when using metrics based upon community similarity. Our results show that, whereas the biodiversity indicator group concept may hold some validity for several taxa that are frequently sampled (such as birds and fruit-feeding butterflies), it fails for those exhibiting highly idiosyncratic responses to tropical land-use change (including highly vagile species groups such as bats and orchid bees), highlighting the problems associated with quantifying the biodiversity value of anthropogenic habitats. Finally, although we show that areas of native regeneration and exotic tree plantations can provide complementary conservation services, we also provide clear empirical evidence demonstrating the irreplaceable value of primary forests.

Frequency of Werner helicase 1367 polymorphism and age-related morbidity in an elderly Brazilian population.

Werner syndrome (WS) is a premature aging disease caused by a mutation in the WRN gene. The gene was identified in 1996 and its product acts as a DNA helicase and exonuclease. Some specific WRN polymorphic variants were associated with increased risk for cardiovascular diseases. The identification of genetic polymorphisms as risk factors for complex diseases affecting older people can improve their prevention, diagnosis and prognosis. We investigated WRN codon 1367 polymorphism in 383 residents in a district of the city of São Paulo, who were enrolled in an Elderly Brazilian Longitudinal Study. Their mean age was 79.70 +/- 5.32 years, ranging from 67 to 97. This population was composed of 262 females (68.4%) and 121 males (31.6%) of European (89.2%), Japanese (3.3%), Middle Eastern (1.81%), and mixed and/or other origins (5.7%). There are no studies concerning this polymorphism in Brazilian population. These subjects were evaluated clinically every two years. The major health problems and morbidities affecting this cohort were cardiovascular diseases (21.7%), hypertension (83.7%), diabetes (63.3%), obesity (41.23%), dementia (8.0%), depression (20.0%), and neoplasia (10.8%). Their prevalence is similar to some urban elderly Brazilian samples. DNA was isolated from blood cells, amplified by PCR and digested with PmaCI. Allele frequencies were 0.788 for the cysteine and 0.211 for the arginine. Genotype distributions were within that expected for the Hardy-Weinberg equilibrium. Female gender was associated with hypertension and obesity. Logistic regression analysis did not detect significant association between the polymorphism and morbidity. These findings confirm those from Europeans and differ from Japanese population.

Frequency of Werner helicase 1367 polymorphism and age-related morbidity in an elderly Brazilian population

Werner syndrome (WS) is a premature aging disease caused by a mutation in the WRN gene. The gene was identified in 1996 and its product acts as a DNA helicase and exonuclease. Some specific WRN polymorphic variants were associated with increased risk for cardiovascular diseases. The identification of genetic polymorphisms as risk factors for complex diseases affecting older people can improve their prevention, diagnosis and prognosis. We investigated WRN codon 1367 polymorphism in 383 residents in a district of the city of São Paulo, who were enrolled in an Elderly Brazilian Longitudinal Study. Their mean age was 79.70 ± 5.32 years, ranging from 67 to 97. This population was composed of 262 females (68.4 percent) and 121 males (31.6 percent) of European (89.2 percent), Japanese (3.3 percent), Middle Eastern (1.81 percent), and mixed and/or other origins (5.7 percent). There are no studies concerning this polymorphism in Brazilian population. These subjects were evaluated clinically every two years. The major health problems and morbidities affecting this cohort were cardiovascular diseases (21.7 percent), hypertension (83.7 percent), diabetes (63.3 percent), obesity (41.23 percent), dementia (8.0 percent), depression (20.0 percent), and neoplasia (10.8 percent). Their prevalence is similar to some urban elderly Brazilian samples. DNA was isolated from blood cells, amplified by PCR and digested with PmaCI. Allele frequencies were 0.788 for the cysteine and 0.211 for the arginine. Genotype distributions were within that expected for the Hardy-Weinberg equilibrium. Female gender was associated with hypertension and obesity. Logistic regression analysis did not detect significant association between the polymorphism and morbidity. These findings confirm those from Europeans and differ from Japanese population.

Helicobacter pylori and cagA and vacA gene status in children from Brazil with chronic gastritis.

Helicobacter pylori has been shown to be strongly associated with chronic gastritis, gastric and duodenal ulceration, and is a risk factor for gastric carcinoma. Histology, urease, culture, and polymerase chain reaction have been employed as for H. pylori diagnostic methods, pre and post treatment or during follow-up of dyspeptic adult individuals referred for endoscopy. In order to obtain a more-sensitive and specific method for H. pylori detection, we evaluated gastric body and antrum biopsies of 134 consecutive Brazilian consecutive dyspeptic children aged 1-16 years by rapid urease test, histology and polymerase chain reaction using two pairs of oligonucleotides. Our results indicated that polymerase chain reaction with Southern blotting and hybridization with specific chemiluminescent probes increased the number of positive H. pylori patients by 35%. The genotyping of H. pylori strains directly from gastric biopsy using the same nucleic acid methodology revealed that there is no association of chronic gastritis in our infant patients with vacA s1 and the presence of the cagA gene. These data suggest an initial infection of children with normal mucosa and probably others factors than vacA s1 genotype or the presence of the cagA gene are associated with the onset of gastric disease. Altogether, our results reinforce the need for using more sensitive diagnostic methods in order to understand the role of H. pylori in the genesis of gastric disease in children and its progression in adults.

Stunning and myocardial contractile autoregulation studied on the isolated isovolumic blood-perfused dog heart.

AIM: To study, for the first time, the effects of stunning on homeometric and heterometric autoregulation. METHODS AND RESULTS: Ischaemia (15 min)/reperfusion (30 min) was induced in the isovolumic blood-perfused dog heart preparation. Heart rate elevations (n = 9) from 60 to 200 beats min-1, in steps of 20 beats min-1, promoted the same inotropic stimulation in control (C) and stunning (S), indicating that ischaemia/reperfusion does not affect the changes in calcium kinetics elicited by the Bowditch effect. Sudden ventricular dilation (VD) (n = 10) evoked an instantaneous increase in developed pressure (Delta1DP) followed by a continuous slow performance increase (Delta2DP) in C and S. Delta1DP (C: 35 +/- 2.2 mmHg; S: 27 +/- 2.1 mmHg; P = 0.002) and Delta2DP (C: 20 +/- 1.6 mmHg; S: 14 +/- 1.3 mmHg; P = 0.002) decreased proportionally, while Delta2/Delta1DP (C: 0.57 +/- 0.13; S: 0.58 +/- 0.14) and slow response time course (T/2) were unchanged (C: 55 +/- 6.6 s; S: 57 +/- 7.7 s) after ischaemia/reperfusion. The reduction of Delta1DP can be understood as a decline of the myofilaments calcium responsiveness, the main pathophysiological effect of stunning. The reason for the weakening of Delta2DP, due to intracellular calcium gain, was not determined but it was supposed that its complete manifestation could be restricted by cyclic adenosine monophosphate (cAMP) myocardial content reduction. As reported by others, Delta2DP depends on myocardial cAMP, and it has been shown that myocardial cAMP is decreased after ischaemia/reperfusion. CONCLUSIONS: Contractile depression due to stunning has no effect on the inotropic stimulation generated by the Bowditch phenomenon. Immediate and time-dependent enhancements of contraction evoked by sudden VD are proportionally reduced and the slow response time course is unaffected in the stunned myocardium.

CFC index for the diagnosis of cardiofaciocutaneous syndrome.

Controversy exists concerning the delineation of cardiofaciocutaneous syndrome (CFC). Many authors have attempted to establish syndrome traits for CFC, but to date none are pathognomonic or obligatory. We have created a clinical and objective method, called the CFC index, for CFC diagnosis. This method also differentiates CFC from Noonan syndrome and Costello syndrome, CFC's main differential diagnosis. We propose the use of the CFC index for the confirmation of CFC diagnosis and to differentiate CFC from other phenotypically similar genetic conditions, while molecular studies are still in progress.

Sawtooth waves during REM sleep after administration of haloperidol combined with total sleep deprivation in healthy young subjects.

We sought to examine the possible participation of dopaminergic receptors in the phasic events that occur during rapid eye movement (REM) sleep, known as sawtooth waves (STW). These phasic phenomena of REM sleep exhibit a unique morphology and, although they represent a characteristic feature of REM sleep, little is known about the mechanisms which generate them and which are apparently different from rapid eye movements. STW behavior was studied in 10 male volunteers aged 20 to 35 years, who were submitted to polysomnographic monitoring (PSG). On the adaptation night they were submitted to the first PSG and on the second night, to the basal PSG. On the third night the volunteers received placebo or haloperidol and spent the whole night awake. On the fourth night they were submitted to the third PSG. After a 15-day rest period, the volunteers returned to the sleep laboratory and, according to a double-blind crossover randomized design, received haloperidol or placebo and spent the whole night awake, after which they were submitted to the fourth PSG. The volunteers who were given haloperidol combined with sleep deprivation exhibited an elevation of the duration and density of the STW, without significant alterations of the other REM sleep phasic phenomena such as rapid eye movement. These findings suggest that sawtooth waves must have their own generating mechanisms and that the dopaminergic receptors must exert a modulating role since REM sleep deprivation, as well as administration of neuroleptics, produces supersensitivity of dopaminergic receptors.

Sawtooth waves during REM sleep after administration of haloperidol combined with total sleep deprivation in healthy young subjects

We sought to examine the possible participation of dopaminergic receptors in the phasic events that occur during rapid eye movement (REM) sleep, known as sawtooth waves (STW). These phasic phenomena of REM sleep exhibit a unique morphology and, although they represent a characteristic feature of REM sleep, little is known about the mechanisms which generate them and which are apparently different from rapid eye movements. STW behavior was studied in 10 male volunteers aged 20 to 35 years, who were submitted to polysomnographic monitoring (PSG). On the adaptation night they were submitted to the first PSG and on the second night, to the basal PSG. On the third night the volunteers received placebo or haloperidol and spent the whole night awake. On the fourth night they were submitted to the third PSG. After a 15-day rest period, the volunteers returned to the sleep laboratory and, according to a double-blind crossover randomized design, received haloperidol or placebo and spent the whole night awake, after which they were submitted to the fourth PSG. The volunteers who were given haloperidol combined with sleep deprivation exhibited an elevation of the duration and density of the STW, without significant alterations of the other REM sleep phasic phenomena such as rapid eye movement. These findings suggest that sawtooth waves must have their own generating mechanisms and that the dopaminergic receptors must exert a modulating role since REM sleep deprivation, as well as administration of neuroleptics, produces supersensitivity of dopaminergic receptors

Paving the way to the future of Amazonia.

The fate of the Brazilian Amazon is threatened by a new wave of frontier expansion following new infrastructure commitments worth US$40 bn from the federal Government. In a recent paper, alarming rates of deforestation and forest degradation have been predicted, which could be either pessimistic or optimistic depending on the scale of forest disturbance being considered. A more decisive preventative approach is needed to prevent further impoverishment of both the biota and rural population of Amazonia.

Riverine barriers and the geographic distribution of Amazonian species.

Rivers have been suggested to have played an important role in shaping present-day patterns of ecological and genetic variation among Amazonian species and communities. Recent molecular studies have provided mixed support for the hypothesis that large lowland Amazonian rivers have functioned as significant impediments to gene flow among populations of neotropical species. To date, no study has systematically evaluated the impact that riverine barriers might have on structuring whole Amazonian communities. Our analyses of the phylogeography of frogs and small mammals indicate that a putative riverine barrier (the Juruá River) does not relate to present-day patterns of community similarity and species richness. Rather, our results imply a significant impact of the Andean orogenic axis and associated thrust-and-fold lowland dynamics in shaping patterns of biotic diversity along the Juruá. Combined results of this and other studies significantly weaken the postulated role of rivers as major drivers of Amazonian diversification.

Density compensation in neotropical primate communities: evidence from 56 hunted and nonhunted Amazonian forests of varying productivity.

Density compensation is a community-level phenomenon in which increases in the abundance of some species may offset the population decline, extirpation, or absence of other potentially interacting competitors. In this paper we examine the evidence for density compensation in neotropical primate assemblages using data from 56 hunted and nonhunted, but otherwise undisturbed, forest sites of Amazonia and the Guianan shields from which population density estimates are available for all diurnal primate species. We found good evidence of density compensation of the residual assemblage of nonhunted mid-sized species where the large-bodied (ateline) species had been severely reduced in numbers or driven to local extinction by subsistence hunters. Only weak evidence for density compensation, however, was detected in small-bodied species. These conclusions are based on the effects of ordinal measures of hunting pressure on the aggregate primate biomass across different size classes after controlling for the effects of forest type and productivity. These results are interpreted primarily in relation to patterns of niche partitioning between different primate functional groups or ecospecies. This study suggests that while overhunting drastically reduces the average body size in multi-species assemblages of forest vertebrates, depletion of large-bodied species is only partially offset (i.e. undercompensated) by smaller taxa.

Effect of physical exercise on seizure occurrence in a model of temporal lobe epilepsy in rats.

Although the favorable effect of physical fitness on general health is unquestionable, physical exercise and fitness programs in patients with epilepsy are still a matter of controversy. Little objective evidence regarding the effect of exercise on seizure frequency and severity has been reported. One sought to clarify the relationship between exercise and epilepsy in an animal model of temporal lobe epilepsy (the pilocarpine model of epilepsy). To evaluate the effect of an aerobic physical program on seizure frequency, 29 epileptic animals were continuously monitored during 24 h for 135 days after the first spontaneous recurrent seizure (SRS) and divided into three groups. The first group (N = 14) was submitted to an aerobic exercise program (training group). The second group (N = 7) was maintained in the treadmill for the same time as the training group without being submitted to physical exercise (sham group). The third group (N = 8) served as control. The behavioral observation was divided in three periods of 45 days. The first period was used to determine the number of seizures before physical training program. The second period was utilized to determine the number of seizures during the physical training program. The third period was used to analyze the frequency of seizures after the physical training program. The mean frequency of seizures in the control and sham groups increased significantly from period 1 to period 2 and from period 1 to period 3. However, in the training group, the frequency of seizures did not change significantly between the three periods of 45 days of observation. When the same periods of the three groups were analyzed together, a significant reduction in seizure frequency was observed comparing the training group with the control and sham groups during the period of physical training. The data presented in this study suggest that physical exercise is not a seizure-inducing factor in this experimental model of epilepsy.

The course of untreated seizures in the pilocarpine model of epilepsy.

The course of untreated epilepsy is not well established. This study uses a model of chronic limbic epilepsy (pilocarpine model of epilepsy) to determine the pattern of occurrence of seizures in untreated animals. Following pilocarpine administration, 21 rats were monitored continuously with a video system for 135 days after the first spontaneous seizure. Animals showed a great variability in seizure numbers and were divided in two subgroups presenting either a low frequency of seizures (n = 9 animals presenting ten or less seizures in the first 15 days of observation) or a high frequency of seizures (n = 12 animals presenting more than ten seizures during this period). Animals with low number of seizures during the first 15 days of observation showed a significant increase in seizure frequency in the following period of analysis (until 105 days). On the other hand, those with initial high number of seizures showed significant changes in seizure frequency only in the first 2 months. The duration of each spontaneous seizure did not change significantly over time. These findings show that in untreated epilepsy there is a maturation process in the early stages and this accelerating process can be of predictive value for the treatment of epilepsy.

Comparison of the biological activities in venoms from three subspecies of the South American rattlesnake (Crotalus durissus terrificus, C. durissus cascavella and C. durissus collilineatus)

The subspecies of the South American rattlesnake, Crotalus durissus are classified according to their external morphological features and geographical distribution. We have determined some biological activities of C. durissus cascavella, C. durissus collilineatus and C. durissus terrificus venoms. C. durissus terrificus had a significantly higher clotting activity on bovine plasma and fibrinogen, human fibrinogen and rabbit plasma. C. durissus cascavella presented a statistically higher phospholipase A2 (PLA2) activity in regard to C. durissus collilineatus. Their myotoxic and proteolytic activity, median lethal doses, or median platelet aggregating doses (on rabbit and human platelets) could not differentiate the three subspecies examined. However, the electrophoretic profile and the dose-response curve for edematogenic activity for C.d. cascavella venom were different from the others. With regard to the inorganic element content of the venoms, higher levels of Br, Cl and Mg, and a lower level of Zn, were found in C.d. cascavella venom. Crotamine-like activity could not be detected in C.d. cascavella venom. Furthermore, equine antivenom specific for C. durissus terrificus venom cross-reacted equally with the antigens of the three venom pools by ELISA and Western blotting. These results indicate that the venoms from the three studied subspecies of C. durissus were very similar, except for minor differences in paw edema-inducing activity, electrophoretic profile, phospholipase A2 activity, crotamine-like activity and inorganic element contents of C.d. cascavella venom.

Age-associated mosaicism and polyploidy in Down's syndrome.

Age-related increases in the frequencies of cells with chromosome 21 loss and of polyploid cells were documented in short-term peripheral blood lymphocyte cultures from 54 patients with Down's syndrome (DS), ages 0 to 48 years. The polyploid data, together with previous work from this laboratory with non-DS subjects, suggest that this may be a useful indicator of aging in lymphocytes.

Rethinking tropical ecosystem management.

Tropical Environments: The Functioning and Management of Tropical Ecosystems by M. Kellman and R. Tackaberry Routledge, 1997. £60.00 hbk, £18.99 pbk (xix+380 pages) ISBN 0 415 11608 2/0 415 11609 0.