Genotyping of Brazilian Giardia duodenalis human axenic isolates

Giardia duodenalis is a complex species that comprises at least seven distinct genetic groups (A to G), but only genotypes A and B are known to infect humans and a wide variety of other mammals. Regardless of biological, biochemical and antigenic analysis, several isolates maintained in vitro were not genetically typed yet. So, in the present study, five Brazilian axenic isolates obtained from asymptomatic and symptomatic patients were typed in order to determine the major genetic groups to which the isolates belonged. DNA was extracted from axenic trophozoites, fragments of glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi) genes were amplified by PCR and the isolate genotyping was carried out using restriction fragment length polymorphism (RFLP) and DNA sequencing for both genes. The results revealed that all isolates were assigned to genotype A at both analyzed loci. Indeed, DNA sequence analysis classified the four isolates obtained from asymptomatic individuals into subtype AII, while the isolate obtained from the symptomatic patient was typed as subtype AI. Despite of the limited number of isolates assessed, the findings presented herein provide interesting insights on the occurrence of Giardia genotypes in Brazil and hold the perspective for future molecular and epidemiological investigations.(AU)

Produção de biomassa e estrutura do pasto de capim-andropogon em sistema silvipastoril e monocultura / Biomass production and pasture structure of Andropogon grass in a silvopastoral system and in monoculture

A produção de biomassa e as características estruturais do capim-andropogon foram avaliadas nas idades de rebrota de 35, 49 e 63 dias, em três ambientes de um sistema silvipastoril: sob a copa de pau-d'arco, sob a copa de jatobá, em área aberta; local fora da copa de qualquer árvore e em sistema de monocultura. O delineamento experimental foi o de parcelas subdivididas com cinco repetições. As parcelas foram representadas pelos ambientes e as subparcelas, pelas idades de rebrota. A luminosidade sob pau-d'arco, sob jatobá e em área aberta foi de 74, 62 por cento e 82 por cento, respectivamente, das áreas a pleno sol. Houve interação ambiente versus idade de rebrota. O sombreamento sob a copa de pau-d'arco e de jatobá não afetou a produção de matéria seca do capim-andropogon, contudo reduziu a altura do pasto aos 63 dias de rebrota. O percentual de folhas da forragem aos 35 dias de rebrota foi mais elevado na monocultura. Nas outras idades de rebrota, os quatro ambientes não diferiram entre si.(AU)

The biomass production and pasture structure of Andropogon grass were evaluated at 35, 49, and 63 days of regrowth, in three silvopastoral environments: under Pau-d'Arco and Jatobá trees, in open field and in monoculture system. The experiment was designed in split plot with five replications, the plots were the environments and the split plots were the regrowth ages. The luminosities under Pau-d'Arco, Jatobá, and open field were: 74, 62, and 82 percent, respectively, relative to the areas under full sun. There was interaction among environments and ages of regrowth. The shading under the canopy of Pau-d'Arco and Jatobá did not affect the production of dry matter of Andropogon grass; however, reduced the height of the grass at 63 days of regrowth. The percentage of leaves of forage at 35 days of regrowth was higher in monoculture. At other ages of regrowth, the four environments did not differ among themselves.(AU)

Avaliação histológica do biovidro particulado na reparação de defeito experimental em mandíbula de cães / Histological evaluation of particulate bioglass in repair of mandible experimental defects in dogs

Avaliou-se histologicamente o biovidro particulado como substituto ósseo na regeneração de defeitos no osso alveolar da mandíbula, utilizando-se 28 cães adultos, divididos em dois grupos. Foram criados defeitos ósseos na superfície vestibular da mandíbula, entre as raízes mesial e distal do quarto pré-molar direito. No grupo tratado, o defeito foi preenchido com biovidro enquanto no outro, o grupo-controle, o defeito permaneceu sem preenchimento. Aos 8, 14, 21, 42, 60, 90 e 120 dias do pós-operatório, foram coletadas amostras da região da falha óssea de dois animais de cada grupo para a análise histológica sob microscopia de luz. No grupo-controle, observou-se início do processo de reparação óssea aos 14 dias que evoluiu até que, aos 120 dias, não havia mais limite entre as margens do defeito e o novo osso. No grupo tratado, aos oito dias, observou-se a presença de tecido conjuntivo frouxo altamente vascularizado ao redor das partículas de biovidro, até que aos 60 dias o biovidro havia sido totalmente reabsorvido, e o defeito apresentava-se completamente preenchido por osso trabecular. Conclui-se que o biovidro é biocompatível, é osteocondutor e diminui o tempo de reparação do osso alveolar.(AU)

By histological analyses, bioglass was evaluated as a bone substitute in the regeneration of alveolar bone defects in mandibles of 28 dogs, which were distributed in two groups. Defects were made in the vestibular surface of the mandible between the roots of the right fourth premolar tooth. In treated group, defects were filled with bioglass, while it did not receive any treatment in the other, being used as control. For histological analyses, samples including the bone defect area of two animals per group were collected after 8, 14, 21, 42, 60, 90, and 120 days after surgery. In the control group, bone repair began on the day 14th, developing until the day 120th, when no limit between the margins of the defect and the new bone existed. In the treated group, at the day eightieth, loose connective tissue highly vascularized around the bioglass particles was observed and on the day 60th, bioglass had been totally reabsorbed and the defect was completely filled by trabecular bone. It can be concluded that the bioglass is biocompatible and osteoconductive, and shortens the time needed for alveolar bone repair.(AU)

Biocompatibilidade e comportamento de compósitos de hidroxiapatita em falha óssea na ulna de coelhos / Biocompatibility and behavior of hydroxyapatite on bone defect on rabbit's ulna

Avaliaram-se os compósitos de hidroxiapatita sintética e carbono (HAC) e hidroxiapatita sintética, carbono e fosfato biácido de sódio (HACF), ambos na forma sólida, como substituto ósseo em 36 coelhos adultos. Após protocolos anestésico e cirúrgico habituais, retirou-se um fragmento de aproximadamente 2cm de comprimento no terço médio da ulna esquerda. Os animais do grupo 1 receberam, em cada falha provocada, blocos de HAC e HACF, e os do grupo 2 somente HAC. Os do grupo 3 não receberam tratamento. Os animais foram submetidos a avaliações clínicas e radiológicas nos dias 8, 15, 30, 60, 120 e 180 de pós-operatório. Nas mesmas datas, dois animais de cada grupo foram sacrificados e deles colheu-se material para histologia. Observou-se evolução normal da regeneração óssea em todos os animais, sendo mais precoce nos dos grupos que receberam os compósitos. O uso de HAC e HACF na ulna de coelho mostrou-se um método eficiente, não apresentando sinais de infecção e nem evidência de rejeição.(AU)

Composites of synthetic hydroxyapatite and carbon (HAC) and synthetic hydroxyapatite, carbon and sodium biacid phosphate (HACF), both of them in solid form, as substitute in bone regeneration were studied. Thirty-six rabbits divided in three groups were used. After routine anesthetic and surgical procedure, a bone fragment with two-centimeter in length was taken from the middle part of the left ulna. Animals from group 1 received one block of HAC and HACF, from group 2 received only HAC, in the criated bone defect, and animals from group 3 did not receive any treatment. They were submitted to clinical and radiographic examinations at 8, 15, 30, 60, 120 and 180 days after surgery to evaluate bone healing. At the same dates, two animals of each group were enthanised and bone fragments were collected for histological evaluations. The results showed normal evolution of bone regeneration in all groups but faster in animals that received the composites. The use of HAC and HACF showed to be efficient and biocompatible, and not caused rejection.(AU)