Potential of Panicum aquanticum Poir. (Poaceae) for the phytoremediation of aquatic environments contaminated by lead

Aquatic environments contaminated by lead (Pb) are a problem in many regions of world. Since Pb has high toxicity, the identification of species for phytoremediation is important for the recovery of these areas. Thus, the phytoremediation potential of Panicum aquaticum Poir. (Poaceae) was evaluated. The anatomical and physiological responses of P. aquaticum were assessed under different concentrations of Pb [0.0, 0.5, 1.0, 2.0, 4.0, and 8.0 mM of Pb(NO₃)₂]. Plant growth, anatomy of roots and leaves, root uptake, root to shoot translocation, and the concentration and accumulation of Pb in organs were analyzed. Regarding leaf anatomy, Pb treatment led to changes in epidermis thickness, stomatal density, stomatal diameter, and sclerenchymal area. Endoderm thickness was increased at the highest concentrations of Pb, which may be related to reduced translocation and shoot accumulation. The roots of P. aquaticum presented increased absorption (2279 μg g^-1 DW^-1 of Pb). In conclusion, P. aquaticum was found to have potential for the phytoremediation of areas contaminated with Pb.

Cadmium tolerance of Typha domingensis Pers. (Typhaceae) as related to growth and leaf morphophysiology

Typha domingensis (cattail) is a native macrophyte known by its capacity to tolerate several heavy metals effects and the potential use for phytoremediation. However, in despite that cadmium (Cd) is one of the most toxic pollutants; its effects in T. domingensis biology remain uninvestigated. Thus, the objective of this study was to study the tolerance of T. domingensis to cadmium contamination by evaluating its growth, Cd uptake, leaf anatomy and gas exchange. The experiment was designed using three cadmium concentrations (0, 10 and 50 µM) and ten replicates for 90 days. The cadmium uptake, growth, gas exchange, chlorophyll content and leaf anatomy were evaluated. Data was submitted to ANOVA and Scott-Knott test for P<0.05. Typha domingensis accumulates Cd proportionally to its concentration on the solution and the content of this metal was higher in roots as compared to shoots. Plants showed no significant modifications on growth parameters such as the biomass production, number of leaves, number of clones and the biomass allocation to organs. The photosynthesis, transpiration and chlorophyll content were not modified by Cd. Most anatomical traits evaluated were not modified by the metal but the stomatal density and the proportion of vascular tissues were reduced under 50 µM of Cd. In despite, the leaf anatomy showed no toxicity evidences for any Cd level. The absence of growth reduction and the stability of anatomical and physiological traits give insight about the Cd tolerance of this species. Therefore, T. domingensis is able to overcome Cd toxicity and shows potential for phytoremediation.

Comparative mathematical modelling of a green approach for bioaccumulation of cobalt from wastewater

Cobalt is an essential element, but its wide use in industry generates important environmental and biological problems. The present study explores theoretical and empirical models of a green process for cobalt {Co²⁺} bioaccumulation from aqueous solutions. Two Gram-positive Bacillus subtilis species, strains CECT 4522 and LMM (the latter a former laboratory isolate from wastewater samples, which was phylogenetically characterized for the present work), were selected among others as the best Co²⁺ accumulation systems. Mathematical models representing kinetic and steady-state conditions for discrete and large amounts of bacterial biomass were expanded. In this way, it was possible to theoretically calculate the amount of Co²⁺ retained on the outer cell wall layer and incorporated inside the cell at any time. Theoretical and empirical hyperbolic-type models were suitable to fit the experimental bioaccumulation data for discrete amounts of bacteria biomass. In addition, kinetic relationships between the amount of Co²⁺ accumulated and the time before (or after) reaching steady state were established for large amounts of bacterial biomass. Other kinetic approaches were also satisfactorily tested. The two Gram-positive bacteria assayed are promising agents for developing heavy metal removal systems from industrial waste.

Anatomical traits related to stress in high density populations of Typha angustifolia L. (Typhaceae)

Some macrophytes species show a high growth potential, colonizing large areas on aquatic environments. Cattail (Typha angustifolia L.) uncontrolled growth causes several problems to human activities and local biodiversity, but this also may lead to competition and further problems for this species itself. Thus, the objective of this study was to investigate anatomical modifications on T. angustifolia plants from different population densities, once it can help to understand its biology. Roots and leaves were collected from natural populations growing under high and low densities. These plant materials were fixed and submitted to usual plant microtechnique procedures. Slides were observed and photographed under light microscopy and images were analyzed in the UTHSCSA-Imagetool software. The experimental design was completely randomized with two treatments and ten replicates, data were submitted to one-way ANOVA and Scott-Knott test at p<0.05. Leaves from low density populations showed higher stomatal density and index. These modifications on stomatal characteristics were more evident on the leaf abaxial surface. Plants from low density populations showed thicker mesophyll and higher proportion of aerenchymal area. Roots from low density populations showed a higher proportion of the vascular cylinder. Whereas, plants from higher density populations showed greater thickness of the endodermis, exodermis, phloem and root cortex. Higher density populations showed a higher proportion of aerenchymal gaps in the root cortex. Therefore, cattail plants from populations growing under high density population show anatomical traits typical of plants under stress, which promotes the development of less functional anatomical modifications to aquatic environments.

Inorganic arsenic speciation by differential pulse anodic stripping voltammetry using thoria nanoparticles-carbon paste electrodes

Two novel thoria (ThO2) nanoparticles-carbon paste electrodes were used to evaluate an anodic stripping voltammetric method for the direct determination of arsenite and total inorganic arsenic (arsenite plus arsenate) in water samples. The effect of Ag((I)), Cu((II)), Hg((II)), Sb((III)) and Se((IV)) ions on the electrochemical response of arsenic was assayed. The developed electroanalytical method offers a rapid procedure with improved analytical characteristics including good repeatability (3.4%) at low As((III)) concentrations, high selectivity, lower detection limit (0.1 μg L(-1)) and high sensitivity (0.54 μA μg(-1) L). The analytical capability of the optimized method was demonstrated by the determination of arsenic in certified reference materials (trace elements in natural water, trace elements in water and coal fly ash).

Low sensitivity of polymerase chain reaction for diagnosis of tuberculous meningitis in southeastern Brazil

Two polymerase chain reaction (PCR) protocols showed low sensitivity (36% and 53% for TB AMPLICOR and MPB64 nested PCR, respectively), when compared with classic microbiological methods (73% and 54% for Ziehl-Neelsen staining and culture, respectively), in the diagnosis of tuberculous meningitis in 91 patients in southeastern Brazil. Only three PCR-positive, microbiologically negative patients were found. Analysis of sequential cerebrospinal fluid samples by nested PCR detected Mycobacterium tuberculosis DNA up to 29 days after the introduction of antituberculosis chemotherapy.

Geographical patterns of allelic diversity in the Plasmodium falciparum malaria-vaccine candidate, merozoite surface protein-2

The polymorphic merozoite surface protein-2 (MSP-2) of Plasmodium falciparum is a major malaria-vaccine candidate. In the present study, PCR and hybridization with allelic-specific probes were used to type the Msp-2 gene from isolates from hypo-endemic Brazil (N = 113), meso-endemic Vietnam (N = 208) and holo-endemic Tanzania (N = 67). The typing methods were designed to group isolates into the dimorphic allelic families FC27 and IC1 and to detect possible between-family recombination events. The analysis was complemented by a comparison of 156 Msp-2 sequences from the GenBank database with 12 additional sequences obtained during the present study. Statistically significant differences were detected in pair-wise comparisons of the distribution of Msp-2 allelic types in Brazil and Vietnam, and in Brazil and Tanzania, but not in Vietnam and Tanzania. The extent of allelic diversity in the Msp-2 gene, as estimated by the total number of different alleles found in a given parasite population and the mean multiplicity of infections, clearly paralleled the levels of malaria endemicity in the study areas. However, no correlation between age and multiplicity of infections was found in the subjects. The patterns of Msp-2 diversity in Brazil appeared to be temporally stable, since no significant difference was observed in the distribution of Msp-2 allelic types among isolates collected, 10--13 years apart, in the same area of Rondônia. Despite the extensive sequence diversity found in Msp-2 alleles, especially in the central repetitive region of the molecule, several instances of identical or nearly identical alleles were found among isolates from different countries and regions, possibly as a result of extensive homoplasy. No recombinant allele was detected by molecular typing in any of the study sites, and the GenBank database included only 12 recombinant sequences (representing 7% of all reported Msp-2 sequences), all of them with an IC1-type 5' end and an FC27-type 3' end. A single, putative, crossover site was characterised for all recombinant alleles. Most of the allelic diversity observed was therefore attributable to variation in the repetitive region of the gene, instead of recombination between alleles of dimorphic families (as commonly found, for example, in the Msp-1 gene). The implications of these findings for studies on the genetic and antigenic diversity of malarial parasites are discussed.

Functional characterization of post-junctional adrenergic receptor subtypes in bovine intra-mammary arteries

We examined the functional role of adrenergic receptor subtypes (ARs) in bovine intra-mammary arteries (IMAs), 1.5-2.5 mm internal diameter. Norepinephrine (NE) and phenylephrine (PE) produced concentration-dependent increases in tone in segments maintained at a previously determined optimal basal tension in vitro. The sensitivity of the tissue to NE and PE, based on -log molar ED50s was 6.87 +/- 0.17 and 7.05 +/- 0.35, respectively. In addition a Schild analysis yielded antagonist affinities for the receptor mediating contractile responses to NE (pA2 value) of 10.46 +/- 0.85 for prazosin and 6.29 +/- 0.18 for yohimbine. These data indicate a dominance of functional alpha 1 (alpha(1)) over alpha 2 (alpha(2))-ARS in this tissue. Based on the inhibitory effects of chloroethylclonidine (CEC) on PE responses and the further reduction in sensitivity when nifedipine was added to the CEC, also in the presence of PE, we conclude that there is more than one alpha(1)-AR subtype, with a predominant role for alpha(1B)-ARs in phenylephrine responses. Stimulation of beta (beta)-ARs, resulted in relatively small reductions in tone (the highest magnitude of response was 25.94 +/- 6.46% of the papaverine maximum at 3 x 10(-6) M isoproterenol); in addition, propranolol did not significantly alter tissue sensitivity to NE. Additional characterization of functional autonomic receptor populations in this circulatory bed will form a basis for future studies on circulatory dynamics in the mammary gland.

Comparison of iodinated contrast media-induced renal vasoconstriction in human, rabbit, dog, and pig arteries

RATIONALE AND OBJECTIVES

Contrast media (CM)-induced renal vasoconstriction is an important factor in the pathogenesis of CM-induced nephrotoxicity. The effects of ionic, high-osmolar CM sodium/meglumine diatrizoate and nonionic, low-osmolar CM iohexol and iopamidol were studied in rabbit, dog, and pig renal arteries and compared with human tissue in an organ bath.

METHODS

Isometric contractions were induced by increasing concentrations of CM and high-osmolar glucose solution.

RESULTS

Contrast media and glucose elicited contractions in human renal arteries of 32% (diatrizoate), 20% (iohexol), 30% (iopamidol), and 22% (glucose). Rabbit and dog renal arteries demonstrated contractions of 30% and 46% (diatrizoate), 15% and 23% (iohexol), 15% and 26% (iopamidol), and 11% and 40% (glucose), respectively, of the control. There was a vasorelaxing effect of all CM tested on pig renal artery.

CONCLUSIONS

Responses in rabbit and dog renal arteries were similar to those in human renal arteries and could serve as models for investigating CM-induced renal vasoconstriction.

Comparative regulation of alpha1-adrenergic receptor mediated contraction in urogenitally derived smooth muscle. Effect of epidermal growth factor

Contractility of smooth muscle within mammalian urogenital organ systems has an established role in physiological/pathophysiological functioning of the component structures. Our aim was to examine the direct effect of epidermal growth factor (EGF) on smooth muscle tone as well as its indirect effects in regulating alpha1-adrenoceptor-mediated contraction of the prostate, the vas deferens and renal arteries. Tissues were mounted isometrically, under controlled conditions, and changes in tension in response to treatment with phenylephrine (PE) with or without pretreatment with EGF were recorded on a physiological recorder via force transducers. In the rabbit prostate, EGF potentiated the magnitude of contraction to PE. The potentiation appeared to be dependent on cyclo-oxygenase products. In the human prostate, EGF potentiated the contractile response to PE. EGF had no effect on the PE-induced contraction of the rabbit renal artery and vas deferens. EGF alone did not alter smooth muscle tone in any of the above-mentioned tissues. The main finding of this study is the difference in the regulation by EGF of the alpha1-adrenoceptor-mediated response in smooth muscle of the prostate, from that by the vas deferens and renal artery. The reasons for this difference in response remain to be elucidated. This study may form the basis for further investigation into receptor transregulation and its relevance to symptomatic benign prostatic hyperplasia (BPH).

Microscopic changes in the retrodiscal tissues of painful temporomandibular joints

PURPOSE

The purpose of this study was to investigate the association between temporomandibular joint (TMJ) pain and histological changes in TMJs with disc displacement.

METHOD

Samples from capsules and posterior disc attachments from 27 TMJ pain patients who underwent surgery were compared with samples from seven asymptomatic persons.

RESULTS

On logistic regression analysis, retrodiscal tissues from the painful joints demonstrated a significantly higher density of fibroblasts, presence of narrowed and obliterated arterial lumens, and a significantly lower distribution of elastic fibers.

CONCLUSION

The results indicate that there is a difference between painful and asymptomatic joints at the microscopic level.

Temporomandibular joint pathosis related to sex, age, and dentition in autopsy material

The purpose of this autopsy study was to test the hypotheses that temporomandibular joint (TMJ) arthrosis is more common in women than in men, increases with age, and is more common in edentulous persons than in those with natural teeth. Two hundred forty-eight TMJs removed at autopsy from 224 fresh cadavers were investigated macroscopically with dissection or cryosectioning. Age was found to be a significant factor in prediction of TMJ arthrosis (p < 0.001) and of disk perforation (p < 0.05). No significant association was found between morphologic changes in the TMJ and the factor of sex for the whole group. Disk displacement and disk perforation were, however, more common in the joints of women than men in the group of persons 80 years of age or older (p < 0.05). There were significant associations (p < 0.001) between arthrosis, disk displacement, disk deformation, and disk perforation. There were no statistically significant differences in the prevalence of morphologic changes in the joints from persons with 10 or more natural teeth in each jaw compared with those from persons without natural teeth. The results of this study showed that TMJ arthrosis is more frequent in older than in younger persons. TMJ disk displacement generally appears necessary for the development of perforations. The findings of this study indicate that sex and dentition are not major factors for the development of TMJ pathosis in elderly individuals.

Morphologic changes in the temporomandibular joint in different age groups. An autopsy investigation

Comparisons among several temporomandibular joint autopsy studies indicate that the frequency of arthrosis and disk displacement is higher in elderly persons. The aim of this study was to investigate type, frequency, and location of morphologic changes in temporomandibular joint autopsy specimens divided into two groups according to age and to determine the differences between the two groups. For this purpose 68 temporomandibular joints were removed from 37 persons at autopsy. Group I (young) consisted of 36 specimens belonging to 19 persons with a mean age of 30 years (range, 16 to 39 years). Group II (elderly) consisted of 32 specimens from persons with a mean age of 68 years (range, 55 to 78 years). Significant differences between the two groups were observed with respect to several of the morphologic changes that were evaluated. The results of this study suggest that the frequency of morphologic changes such as deviation in form, arthrosis, perforations, disk displacement, disk deformation, and adhesions is higher in the temporomandibular joints of elderly persons.

Clinical findings related to morphologic changes in TMJ autopsy specimens

Numerous temporomandibular joint autopsy studies have been presented in the literature for the last two decades, but signs and symptoms of temporomandibular disorders before death were not available. To investigate the clinical significance of morphologic changes in the temporomandibular joint, 19 persons were clinically examined for signs and symptoms of temporomandibular disorders. The temporomandibular joints were subsequently analyzed macroscopically at autopsy and statistically associated with history and clinical findings. The average time between clinical examination and autopsy was 12 months. Signs and symptoms of temporomandibular disorders were not common findings for these persons. Morphologically, 31 of the 34 joints showed different forms of changes such as deviation in form, arthrosis, disk displacement, disk deformation, and adhesions. Crepitation showed a significant association with arthrosis. It was concluded that the association between pain and dysfunction and joint morphology is complex and gross morphologic alterations can be present in the absence of temporomandibular joint pain and dysfunction.

[Myxoma of the right atrium]

The authors report the case of a 31 year-old male with right atrial myxoma whose clinical manifestations included: malaise, dizziness and dyspnea on great exertion. At physical examination, a tricuspid systolic and diastolic murmur of mean intensity was found. The chest radiography and the electrocardiogram signs were of right atrial and ventricular enlargement, and the diagnosis was made with the B-mode echocardiogram. The patient underwent surgical removal of the tumoral mass and diagnostic confirmation was made with the histopathologic study of the 75 x 50 x 40 mm piece. The patient obtained clinical, electrocardiographic and radiologic remission.