Cytogenetic analysis in the spermatogenesis of Triatoma melanosoma (Reduviidae; Heteroptera)

Triatomines are of great concern in public health because they are vectors of Chagas' disease. This study presents an analysis of the species Triatoma melanosoma. The cytogenetic characteristics of triatomines include holocentric chromosomes, post-reductional meiosis in the sex chromosomes and nucleolar fragmentation in the meiotic cycle. The methodology utilized consisted of the techniques of lacto-acetic orcein staining and silver ion impregnation. The organs analyzed were adult testicles. The results enabled to classify the chromosomes by number and size, being three large, eight medium and one small heterochromosome. The three largest chromosomes and the heterochromosomes showed heteropyknotic chromatin in meiosis. The heterochromosomes in 8.05% of the cells in metaphase I behaved as pseudobivalents, contrasting with 91.95% of the cells with individualized sex chromosomes, confirming the achiasmatic nature of these chromosomes. However, the pseudobivalents occurred prominently in metaphase II (78.38%), this fact probably is related to the post-reductional nature of the sex chromosomes. The nucleolus in T. melanosoma persisted until the diplotene phase after which it began to fragment. Nucleolar corpuscles were observed in metaphases I and II and during anaphases I and II, these characteristics being related to the phenomenon of nucleolar persistence. In the initial spermatids, peripheral silver ion impregnation occurred, which could be analogous to the pre-nucleolar corpuscles observed after fragmentation. Thus, this study extends our knowledge of the characteristics of triatomines, in particular, heteropyknotic degree, kinetic activity, formation of sex chromosome achiasmatic pseudobivalency, confirmation of the fragmentation phenomenon, and post-meiotic nucleolar reactivation. ©FUNPEC-RP.

Evaluation of bone ingrowth into porous titanium implant: Histomorphometric analysis in rabbits

A porous material for bone ingrowth with adequate pore structure and appropriate mechanical properties has long been sought as the ideal bone-implant interface. This study aimed to assess in vivo the influence of three types of porous titanium implant on the new bone ingrowth. The implants were produced by means of a powder metallurgy technique with different porosities and pore sizes: Group 1 = 30% and 180 μm; Group 2 = 30% and 300 μm; and Group 3 = 40% and 180 μm. Six rabbits received one implant of each type in the right and left tibiae and were sacrificed 8 weeks after surgery for histological and histomor-phometric analyses. Histological analysis confirmed new bone in contact with the implant, formed in direction of pores. Histomorphometric evaluation demonstrated that the new bone formation was statistically significantly lower in the group G1 than in group G3, (P = 0.023). Based on these results, increased porosity and pore size were concluded to have a positive effect on the amount of bone ingrowth.

A methodological approach to gender analysis in natural disaster assessment: a guide for the Caribbean

Includes bibliography

Harmonic propagation analysis in electric energy distribution systems

An important alteration of the equivalent loads profile has been observed in the electrical energy distribution systems, for the last years. Such fact is due to the significant increment of the electronic processors of electric energy that, in general, behave as nonlinear loads, generating harmonic distortions in the currents and voltages along the electric network. The effects of these nonlinear loads, even if they are concentrated in specific sections of the network, are present along the branch circuits, affecting the behavior of the entire electric network. For the evaluation of this phenomenon it is necessary the analysis of the harmonic currents flow and the understanding of the causes and effects of the consequent voltage harmonic distortions. The usual tools for calculation the harmonic flow consider one-line equivalent networks, balanced and symmetrical systems. Therefore, they are not tools appropriate for analysis of the operation and the influence/interaction of mitigation elements. In this context, this work proposes the development of a computational tool for the analysis of the three-phase harmonic propagation using Norton modified models and considering the real nature of unbalanced electric systems operation. © 2011 IEEE.

Biomedical Ti-Mo Alloys with Surface Machined and Modified by Laser Beam: Biomechanical, Histological, and Histometric Analysis in Rabbits

Purpose: In vivo bone response was assessed by removal torque, hystological and histometrical analysis on a recently developed biomedical Ti-15Mo alloy, after surface modification by laser beam irradiation, installed in the tibia of rabbits. Materials and Methods: A total of 32 wide cylindrical Ti-15Mo dental implants were obtained (10mm × 3.75mm). The implants were divided into two groups: 1) control samples (Machined surface - MS) and 2) implants with their surface modified by Laser beam-irradiation (Test samples - LS). Six implants of each surface were used for removal torque test and 10 of each surface for histological and histometrical analysis. The implants were placed in the tibial metaphyses of rabbits. Results: Average removal torque was 51.5Ncm to MS and >90Ncm to LS. Bone-to-implant-contact percentage was significantly higher for LS implants both in the cortical and marrow regions. Conclusions: The present study demonstrated that laser treated Ti-15Mo alloys are promising materials for biomedical application. © 2011 Wiley Periodicals, Inc.

Impact of diabetes mellitus and metabolic control on bone healing around osseointegrated implants: Removal torque and histomorphometric analysis in rats

Objectives: To evaluate bone healing around dental implants with established osseointegration in experimental diabetes mellitus (DM) and insulin therapy by histomorphometric and removal torque analysis in a rat model. Materials and methods: A total of 80 male Wistar rats received a titanium implant in the tibiae proximal methaphysis. After a healing period of 60 days, the rats were divided into four groups of 20 animals each: a 2-month control group, sacrificed at time (group A), a diabetic group (group D), an insulin group (group I), and a 4-month control group (group C), subdivided half for removal torque and half for histomorphometric analysis. In the D and I groups the DM was induced by a single injection of 40 mg/kg body weight streptozotocin (STZ). Two days after DM induction, group I received subcutaneous doses of insulin twice a day, during 2 months. Groups C and D received only saline. Two months after induction of DM, the animals of groups D, C and I were sacrificed. The plasmatic levels of glucose (GPL) were monitored throughout the experiment. Evaluation of the percentages of bone-to-implant contact and bone area within the limits of the implant threads was done by histomorphometric and mechanical torque analysis. Data were analyzed by anova at significant level of 5%. Results: The GPL were within normal range for groups A, C and I and higher for group D. The means and standard deviations (SD) for histomorphometric bone area showed significant difference between group D (69.34 ± 5.00%) and groups C (78.20 ± 4.88%) and I (79.63 ± 4.97%). Related to bone-to-implant contact there were no significant difference between the groups D (60.81 + 6.83%), C (63.37 + 5.88%) and I (66.97 + 4.13%). The means and SD for removal torque showed that group D (12.91 ± 2.51 Ncm) was statistically lower than group I (17.10 ± 3.06 Ncm) and C (16.95 ± 5.39 Ncm). Conclusions: Diabetes mellitus impaired the bone healing around dental implants with established osseointegration because the results presented a lower percentage of bone area in group D in relation to groups C and I resulting in a lowest torque values for implant removal. Moreover, insulin therapy prevents the occurrence of bone abnormalities found in diabetic animals and osseointegration was not compromised. © 2012 John Wiley & Sons A/S.

Commercially pure titanium implants with surfaces modified by laser beam with and without chemical deposition of apatite. Biomechanical and topographical analysis in rabbits

Objectives: The purpose of this study was to evaluate the surfaces of commercially pure titanium (cp Ti) implants modified by laser beam (LS), without and with hydroxyapatite deposition by the biomimetic method (HAB), without (HAB) and with thermal treatment (HABT), and compare them with implants with surfaces modified by acid treatment (AS) and with machined surfaces (MS), employing topographical and biomechanics analysis. Methods: Forty-five rabbits received 75 implants. After 30, 60, and 90 days, the implants were removed by reverse torque and the surfaces were topographically analyzed. Results: At 30 days, statistically significant difference (P < 0.05) was observed among all the surfaces and the MS, between HAB/HABT and AS and between HAB and LS. At 60 days, the reverse torque of LS, HAB, HABT, and AS differed significantly from MS. At 90 days, difference was observed between HAB and MS. The microtopographic analysis revealed statistical difference between the roughness of LS, HAB, and HABT when compared with AS and MS. Conclusions: It was concluded that the implants LS, HAB, and HABT presented physicochemical and topographical properties superior to those of AS and MS and favored the osseointegration process in the shorter periods. In addition, HAB showed the best results when compared with other surfaces. © 2012 John Wiley & Sons A/S.

Stress analysis in bone tissue around single implants with different diameters and veneering materials: A 3-D finite element study

The aimof this study was to evaluate the stress distribution on bone tissue with a single prosthesis supported by implants of large and conventional diameter and presenting different veneering materials using the 3-D finite elementmethod. Sixteenmodels were fabricated to reproduce a bone block with implants, using two diameters (3.75 × 10 mmand 5.00 × 10 mm), four different veneering materials (composite resin, acrylic resin, porcelain, and NiCr crown), and two loads (axial (200 N) and oblique (100 N)). For data analysis, the maximum principal stress and vonMises criterion were used. For the axial load, the cortical bone in allmodels did not exhibit significant differences, and the trabecular bone presented higher tensile stresswith reduced implant diameter. For the oblique load, the cortical bone presented a significant increase in tensile stress on the same side as the loading for smaller implant diameters. The trabecular bone showed a similar but more discreet trend. There was no difference in bone tissue with different veneering materials. The veneering material did not influence the stress distribution in the supporting tissues of single implant-supported prostheses. The large-diameter implants improved the transference of occlusal loads to bone tissue and decreased stress mainly under oblique loads.Oblique loading was more detrimental to distribution stresses than axial loading. © 2013 Elsevier B.V. All rights reserved.

Needs assessment of economic planning units in gender analysis in selected Caribbean countries

Includes bibliography

Comparative cytogenetic analysis in the species Uroderma magnirostrum and U. bilobatum (cytotype 2n = 42) (Phyllostomidae, Stenodermatinae) in the Brazilian Amazon

The genus Uroderma includes two species: U. magnirostrum and U. bilobatum. These species are characterized by their high degree of karyotypic evolution, diverging from most other species of the subfamily Stenodermatinae, which have a lower degree of chromosomic evolution. The present study reports the first banding patterns of U. magnirostrum (G-, C-banding and Ag-NOR) and U. bilobatum (C-banding and Ag-NOR). The chromosomic data in conventional staining of U. magnirostrum (2n = 36, NF = 62) and U. bilobatum (cytotype 2n = 42, NF = 50) are equivalent to that described in the literature. When compared, chromosomal homeologies are found in both karyotypes, as well as differences, confirming that karyotypic evolution in the Uroderma genus is intense. Fission, fusion, inversion or translocation events are required to explain the karyotypic evolution of this genus. The comparison of karyotype, described here, to one of the species of the genus Artibeus (2n = 30/31), suggests that some chromosomic forms are apomorphic and shared between the two species of Uroderma. This confirms the monophyly of the enus, and that U. magnirostrum presents a more primitive karyotype when compared to U. bilobatum

Karyotypic analysis in species of the genus Dasyprocta (Rodentia: Dasyproctidae) found in Brazilian Amazon

Foram estudados citogeneticamente um total de 30 animais das espécies D. prymnolopha (N=20), D. leporina (N=6), D. fuliginosa (N=1) e Dasyprocta sp. (N=3) (Dasyproctidae, Histricognathi). As preparações cromossômicas foram obtidas do cultivo de sangue periférico, além de medula óssea e baço em D. prymnolopha e D. leporina. O número diplóide foi de 64/65 em todos os exemplares. O cariótipo mostrou similaridade, não sendo detectado, através de coloração convencional de giemsa e de banda G, polimorfismo cromossômico em qualquer uma das espécies estudadas. A distribuição da heterocromatina constitutiva na região pericentromérica de todos os cromossomos foi similar nas quatro espécies. D. prymnolopha, D. leporina e Dasyprocta sp. apresentaram variação no tamanho do bloco heterocromático em um dos homólogos do par A18. D. fuliginosa apresentou a heterocromatina uniformemente distribuída em todos os cromossomos. Não houve variação no padrão das RONs entre as espécies estudadas.

Analogia entre propriedades de alguns polinômios ortogonais em uma e em várias variáveis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Polymorphism analysis in genes of the somatotropic axis in Nellore cattle selected for growth

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

Delimiting the Origin of a B Chromosome by FISH Mapping, Chromosome Painting and DNA Sequence Analysis in Astyanax paranae (Teleostei, Characiformes)

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