Palynostratigraphy and sedimentary facies of Middle Miocene fluvial deposits of the Amazonas Basin, Brazil

Palynostratigraphic and sedimentary fades analyses were made on sedimentary deposits from the left bank of the Solimoes River, southwest of Manaus. State of Amazonas, Brazil. These provided the age-elating and subdivision of a post-Cietaceous stratigraphic succession in the Amazonas Basin. The Novo Remanso Formation is subdivided into upper and lower units, and delineated by discontinuous surfaces at its top and bottom. The formation consists primarily of sandstones and minor mudstones and conglomerates, reflecting fluvial channel, point bar and floodplain facies of a fluvial meandering paleosystem. Fairly well-preserved palynoflora was recovered from four palynologically productive samples collected in a local irregular concentration of gray clay deposits, rich in organic material and fossilized wood, at the top of the Nova Remanso Formation upper unit. The palynoflora is dominated by terrestrial spores and pollen grains, an d is characterized by abundant angiosperm pollen grains (Tricolpites, Grimsdalea, Perisyncolporites, Tricolporites and Malvacearumpollis). Trilete spores are almost as abundant as the angiosperm pollen, and are represented mainly by the genera Deltoidospora. Verrutriletes, and Hamulatisporis. Gymnosperm pollen is scarce. The presence of the index species Grimsdalea magnaclavata Germeraad et al. (1968) indicates that these deposits belong to the Middle Miocene homonymous palynozone (Lorente, 1986; Hoorn, 1993; Jaramillo et al., 2011). Sedimentological characteristics (poorly sorted, angular to sub-angular, fine to very-coarse quartz sands facies) are typical of the NOW Remanso Formation upper part. These are associated with a paleoflow to the NE-E and SE-E, and with a a entirely lowland-derived palinofloristic content with no Andean ferns and gymnosperms representatives. All together, this suggests a cratonic origin for this Middle Miocene fluvial paleosystem, which was probably born in the Purus Arch eastern flank and areas surrounding the crystalline. The palynological analysis results presented herein are the first direct and unequivocal evidence of the occurrence of Middle Miocene deposits in the central part of the Amazonas Basin. They also provide new perspectives for intra- and interbasin correlations, as well as paleogeographic and paleoenvironmental interpretations for the later deposition stages in the northern Brazilian sedimentary basins. (C) 2011 Elsevier Ltd. All rights reserved.

Geochemical constraints on blueschist- and amphibolite-facies rocks of the Central Cordillera of Colombia: the Andean Barragan region

Subduction zones are one of the most characteristic features of planet Earth. Convergent plate junctions exert enormous influence on the formation and recycling of continental crust, and they are also responsible for major mineral resources and earthquakes, which are of crucial importance for society. A subduction-related geologic unit containing high-pressure rocks occurs in the Barragan area (Valle del Cauca Department) on the western flank of the Central Cordillera of the Colombian Andes. Blueschists and amphibolites, serpentinized meta-ultramafic rocks, graphite-chlorite-muscovite-quartz schists, protocataclasites, and graphite-chlorite-andalusite-andesine-garnet-muscovite +/- titanite schists are exposed in this region. In spite of the petrotectonic importance of blueschists, the high-pressure metamorphism of the Central Cordillera of Colombia has been rarely studied. New geochemical data indicate that protoliths of the blueschist- and amphibolite-facies rocks possessed normal mid-ocean ridge basalt bulk compositions. Ar-40/Ar-39 geochronology for a metapelite rock associated with the blueschists shows a plateau age of similar to 120 million years. We suggest that high-P/T conditions were present from similar to 150 to 125 Ma, depending on the model of generation and exhumation considered.

Fish Oil Supplementation Reduces Cachexia and Tumor Growth While Improving Renal Function in Tumor-Bearing Rats

The objective of the present work was to study the renal function of healthy and tumor-bearing rats chronically supplemented with fish oil (FO), a source of n-3 polyunsaturated fatty acids. Weanling male rats were divided in two groups, one control (C) and another orally supplemented for 70 days with FO (1 g/kg body weight). After this time, half the animals of each group were injected in the right flank with a suspension of Walker 256 tumor cells (W and WFO). The W group had less proteinemia reflecting cachectic proteolysis, FO reversed this fact. Tumor weight gain was also reduced in WFO. Glomerular filtration rate (GFR) was not different in FO or W compared to C, but was higher in WFO. Renal plasma flow (RPF) was higher in the FO supplemented groups. The W group had lower plasma osmolality than the C group, but FO supplementation resulted in normalization of this parameter. Fractional sodium excretion (FENa+) of FO rats was similar to C. Proximal Na+ reabsorption, evaluated by lithium clearance, was similar among the groups. Urinary thromboxane B-2 (TXB2) excretion was lower in the supplemented groups. The number of macrophages in renal tissue was higher in W compared to C rats, but was lower in WFO rats compared to W rats. In conclusion, FO supplementation resulted in less tumor growth and cachexia, and appeared to be renoprotective, as suggested by higher RPF and GFR.

Topical Treatment Using Amphotericin B and DMSO for an Atypically Located Equine Cutaneous Pythiosis

Background: Cutaneous lesions by Pythium insidiosum infection are commonly observed in horses, especially in those living at flooded environments. Equine pythiosis is characterized by the development of tumoral masses that are frequently located at distal limbs, ventral abdomen, thorax, breast and face. The lesions are usually granulomatous, serosanguineous and ulcerated, most often destroyed by self-mutilation due to the intense pruritus. The proposed treatment includes surgical excision followed by antifungal drugs administration, which can be done systemically or topically. Amphotericin B and dimethyl sulfoxide (DMSO) in association has been successfully used for cutaneous pythiosis topical treatment due to the DMSO property to carry any substance through plasmatic membranes. Case: The present report concerns a 12-year-old mixed breed gelding presenting with self-mutilation of a tumoral mass located at the left flank. The owners reported that the horse had initially presented a small wound that had evolved to a 20-cm in diameter mass in 4 weeks. Tissue samples were collected, processed and stained by the Gomori's methenamine silver (GMS) method. The histopathological analysis revealed Pythium insidiosum hyphae in a granulomatous tissue, especially located at peripheral region, where kunkers were present. Surgical excision of the mass followed by cauterization was indicated as initial treatment, and due to financial reasons, the owners elected only the topical antifungal therapy to control the fungus infection after surgery. Flunixin meglumine was also administrated for five days aiming the control of pain and inflammation. The wound was cleaned with povidone-iodine solution and rinsed with a solution containing, 50 mg, of amphotericin B in 10 mL of sterile water and 10 mL of DMSO. This procedure was carried Out twice a day. The wound healed fast due to an excellent centripetal epithelialization. and the horse was discharged after 64 days showing only 5% of the initial wound area. The owner reported by telephone the complete healing and hair growth 10 days after discharge. Discussion: Despite the atypical location of the tumoral lesion described at the present report, the history and clinical manifestations, especially the intense pruritus, showed similarity with other characteristic reports of equine cutaneous pythiosis. The diagnosis was confirmed by the histopathological examination showing hyphae structures, as described to be evidences of the presence of Pythium insidiosum in the tissue. The surgical procedure was the first step to provide remission of clinical signs, and one day after surgery the pruritus desapeared. After excision of the granulomatous tissue and cauterization, daily topical administration of amphotericin B associated with DMSO was effective in destroying the infectious agent, as observed by the excellent epithelization. A pink granulation tissue grew up providing an ideal surface for epithelial migration and the healing process progressed quickly. Centripetal epithelialization reduced the wound area until 3% of the initial area in 64 days of treatment, when the remaining wound was found almost completely healed and covered with hair. At the present report, the horse presenting pythiosis was only topically treated. The recommended therapy using amphotericin B and DMSO solution was effective, economically viable and low risk, considering that the systemic antifungal therapy usually suggested is expensive and extremely nephrotoxic. The atypical location of the lesion on the left flank shows that any anatomical region can be affected by the fungus, since the conditions for its development were present.

Apoptotic Cells Contribute to Melanoma Progression and This Effect is Partially Mediated by the Platelet-Activating Factor Receptor

There is evidence that the platelet-activating factor receptor (PAFR) is involved in the clearance of apoptotic cells by macrophages, and that this is associated with anti-inflammatory phenotype. Our group has previously shown that coinjection of a large number of apoptotic cells can promote tumor growth from a subtumorigenic dose of melanoma cells. Here, we studied the involvement of the PAFR in the tumor growth promoting effect of apoptotic cells. A sub-tumorigenic dose of melanoma cells (Tm1) was coinjected with apoptotic Tm1 cells, subcutaneously in the flank of C57Bl/6 mice, and the volume was monitored for 30 days. Animals received the PAFR antagonists, WEB2170 or PCA4248 (5 mg/kg body weight) or vehicle, by peritumoral daily injection for 5 days. Results showed that PAFR antagonists significantly inhibited the tumor growth induced by the coinjection of a subtumorigenic dose of melanoma cells together with apoptotic cells. This was accompanied by inhibition of early neutrophil and macrophage infiltration. Addition of (platelet-activating factor) to this system has no significant effect. PAFR antagonists did not affect the promoting effect of carrageenan. We suggest that the recognition of apoptotic cells by phagocytes leads to activation of PAFR pathways, resulting in a microenvironment response favorable to melanoma growth.

Iheringichthys syi (Siluriformes: Pimelodidae), a new pimelodid species from upper Parana basin, Brazil

We describe a new species of pimelodid catfish of the genus Iheringichthys from the upper Parana basin, Brazil Iheringichthys syi n. sp. is distinguished by the comparatively fine serration along the anterior margin of the pectoral-fin spine, an adpressed dorsal-fin remote from the adipose-fin origin, a large eye (23.2-31.2% of head length), narrow interorbital (16.2-23.0% of head length), long snout (42.0-51.0% of head length), long postorbital length (30.6-34.0% of head length), low adipose fin (4.8-7.8% of standard length), eye diameter 97.0-140.0% of interorbital length, and body with numerous, small dots irregularly scattered on flanks, especially marked on anterior half of flank.

The influence of rifting on escarpment migration on high elevation passive continental margins

Using numerical models that couple surface processes, flexural isostasy, faulting and the thermal effects of rifting, we show that fault-bounded escarpments created at rift flanks by mechanical unloading and flexural rebound have little potential to "survive" as retreating escarpments if the lower crust under the rift flank is substantially stretched. In this configuration, a drainage divide that persists through time appears landward of the initial escarpment in a position close to a secondary bulge that is created during the rifting event at a distance that depends on the flexural rigidity of the upper crust. Moreover, the migration of the escarpment to the secondary bulge occurs when the pre-rift topography dips landward, otherwise the evolution of the escarpment is guided by the pre-existing inland drainage divide. To illustrate this new mechanism for the evolution of passive margins, we study the examples of Southeastern Australia and Southeastern Brazil. We propose that a pre-existing inland drainage divide with rift related flank uplift can produce the double drainage divide observed in Southeastern Australia. On the other hand, we conclude that it is possible that the Serra do Mar escarpments on the Southeastern Brazilian margin originated as a secondary flexural bulge during rifting that persisted through time. In both cases, the retreating escarpment scenario is unlikely and the present-day margin morphology can be explained as resulting from rift-related vertical motions alone, without requiring significant post-rift "rejuvenation".

Spontaneous combined rupture of a pelvicalyceal cyst into the collector system and retroperitoneal space during the acquisition of computed tomography scan images: a case report

Abstract Introduction Pelvicalyceal cysts are common findings in autopsies and can manifest with a variety of patterns. These cystic lesions are usually a benign entity with no clinical significance unless they enlarge enough to cause compression of the adjacent collecting system and consequently obstructive uropathy. Few cases of the spontaneous rupture of pelvicalyceal renal cysts have been published and to the best of our knowledge there is no report of a combined rupture to collector system and retroperitoneal space documented during a multiphase computed tomography. Case presentation We report a case of a ‘real-time’ spontaneous rupture of a pelvicalyceal cyst into the collecting system with fistulization into the retroperitoneum. The patient was a 78-year-old Caucasian man with a previous history of renal stones and a large pelvicalyceal renal cyst who was admitted to our Emergency department with acute right flank pain. A multiphase computed tomography was performed and the pre-contrast images demonstrated a right pelvicalyceal renal cyst measuring 12.0 × 6.1cm in the lower pole causing moderate dilation of the upper right renal collection system. In addition, a partially obstructive stone on the left distal ureter with mild left hydronephrosis was noted. The nephrographic phase did not add any new information. The excretory phase (10-minute delay) demonstrated a spontaneous rupture of the cyst into the pelvicalyceal system with posterior fistulization into the retroperitoneal space. Conclusion In this case study we present time-related changes of a rare pelvicalyceal cyst complication, which to the best of our knowledge has fortunately not been previously documented. Analysis of the sequential images and comparison with an earlier scan allowed us to better understand the physiopathological process of the rupture, the clinical presentation and to elaborate hypotheses for its etiopathogenesis.

Iheringichthys syi (Siluriformes: Pimelodidae), a new pimelodid species from upper Paraná basin, Brazil

We describe a new species of pimelodid catfish of the genus Iheringichthys from the upper Paraná basin, Brazil. Iheringichthys syi n. sp. is distinguished by the comparatively fine serration along the anterior margin of the pectoral-fin spine, an adpressed dorsal-fin remote from the adipose-fin origin, a large eye (23.2-31.2% of head length), narrow interorbital (16.2-23.0% of head length), long snout (42.0-51.0% of head length), long postorbital length (30.6-34.0% of head length), low adipose fin (4.8-7.8% of standard length), eye diameter 97.0-140.0% of interorbital length, and body with numerous, small dots irregularly scattered on flanks, especially marked on anterior half of flank.

What drives the seasonality of photosynthesis across the Amazon basin? A cross-site analysis of eddy flux tower measurements from the Brasil flux network

We investigated the seasonal patterns of Amazonian forest photosynthetic activity, and the effects thereon of variations in climate and land-use, by integrating data from a network of ground-based eddy flux towers in Brazil established as part of the ‘Large-Scale Biosphere Atmosphere Experiment in Amazonia’ project. We found that degree of water limitation, as indicated by the seasonality of the ratio of sensible to latent heat flux (Bowen ratio) predicts seasonal patterns of photosynthesis. In equatorial Amazonian forests (5◦ N–5◦ S), water limitation is absent, and photosynthetic fluxes (or gross ecosystem productivity, GEP) exhibit high or increasing levels of photosynthetic activity as the dry season progresses, likely a consequence of allocation to growth of new leaves. In contrast, forests along the southern flank of the Amazon, pastures converted from forest, and mixed forest-grass savanna, exhibit dry-season declines in GEP, consistent with increasing degrees of water limitation. Although previous work showed tropical ecosystem evapotranspiration (ET) is driven by incoming radiation, GEP observations reported here surprisingly show no or negative relationships with photosynthetically active radiation (PAR). Instead, GEP fluxes largely followed the phenology of canopy photosynthetic capacity (Pc), with only deviations from this primary pattern driven by variations in PAR. Estimates of leaf flush at three