RESUMO

In this work, we analyse morpho-physiological modifications presented during the allomorphic growth of the aroid vine Rhodospatha oblongata Poepp throughout its ascent into the forest canopy. We test the hypothesis that morphological modifications in the root, shoot and leaf are followed by a gradual improvement of the xylem vascular system in order to increase water acquisition and transport as body size increases. The characterisation of these structural modifications was based on 30-35 specimens divided into six size classes. The dimensions of shoots, leaves and roots were quantified and qualified. The transition from the terrestrial to the epiphytic phase was followed by a simultaneous increase of leaf number and lamina area, together with increased length and diameter of the petiole. Furthermore, as the plant grows, the shoot internodes become shorter and thicker. However, occurrence of aerial roots is the most important characteristic in the ascending phase. In taller individuals, the increase in number of roots with wider xylem vessels guarantees an increased theoretical xylem hydraulic conductance for this growth phase. Along an acropetal direction of the same shoot, the diameter of xylem vessels increased, while the number of vessels per stele area decreased, in contrast with such allometric models as that of West, Brown and Enquist, showing that xylem vessel number and diameter taper in a reverse manner along the same direction. Such structural changes of R. oblongata allow improved foraging for light and water, facilitating the survival of bigger-sized plants of this vine in the canopy.

Assuntos

RESUMO

Investigaram-se os eventos morfológicos relacionados ao desenvolvimento pré-natal de ovários de 81 embriões e fetos da raça Nelore, coletados em frigoríficos, com idades variando de 26 a 240 dias pós-fecundação. Observou-se formação da crista gonádica e presença de células germinativas em seu interior aos 29 e 34 dias, respectivamente. As oogônias e folículos primordiais, ao contrário dos folículos em crescimento, apresentaram diferenças significativas de diâmetro nos vários períodos estudados. Verificou-se correlação positiva (P<0,05) entre o diâmetro das oogônias e de seus núcleos, bem como entre o diâmetro dos folículos primordiais e em crescimento com seus oócitos e respectivos núcleos. A gônada apresentou-se completamente formada aos 40 dias. Folículos primordiais, em crescimento e antrais surgiram, aproximadamente, aos 95, 140 e 180 dias, respectivamente. Na raça Nelore, a oogênese tem início e duração semelhante à de raças taurinas, mas apresenta como peculiaridade a antecipação do surgimento da foliculogênese.(AU)

The morphologic events related to the prenatal development of the ovaries in 81 Nelore breed embryos and fetuses gathered in a local slaughterhouse, with age range from 26 to 240 days following fecundation were studied. The age of fetuses was estimated from measures taken in the cranium-caudal direction. The sex was identified from macroscopic observations and using Polymerase Chain Reaction (PCR) technique. For histology the gonads were fixed in Bouins fluid for 24 hours and 5 µm thick sections were stained with hematoxylin-eosin. Formation of gonadal ridge and presence of germinal cells were found within it at 29 and 34 days, respectively. Oogonia and primordial follicles, unlike the growing follicles, exhibited significant differences in diameter in the various periods studied. Positive correlation (P<0.05) was found between the diameter of oogonia and their nucleus as well as between primordial and growing follicles with their oocytes and respective nuclei. The gonad was fully formed at 40 days. Primordial follicles, in the growing stage, and antral follicles first appeared, approximately at 95, 140, and 180 days, respectively. Despite the onset and duration of oogenesis being similar to that of taurine breeds, folliculogenesis initiates at an early stages in the Nelore breed.(AU)

Assuntos

RESUMO

Investigaram-se os eventos morfológicos relacionados ao desenvolvimento pré-natal de ovários de 81 embriões e fetos da raça Nelore, coletados em frigoríficos, com idades variando de 26 a 240 dias pós-fecundação. Observou-se formação da crista gonádica e presença de células germinativas em seu interior aos 29 e 34 dias, respectivamente. As oogônias e folículos primordiais, ao contrário dos folículos em crescimento, apresentaram diferenças significativas de diâmetro nos vários períodos estudados. Verificou-se correlação positiva (P<0,05) entre o diâmetro das oogônias e de seus núcleos, bem como entre o diâmetro dos folículos primordiais e em crescimento com seus oócitos e respectivos núcleos. A gônada apresentou-se completamente formada aos 40 dias. Folículos primordiais, em crescimento e antrais surgiram, aproximadamente, aos 95, 140 e 180 dias, respectivamente. Na raça Nelore, a oogênese tem início e duração semelhante à de raças taurinas, mas apresenta como peculiaridade a antecipação do surgimento da foliculogênese.

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RESUMO

Fully developed leaves of Cryptochloa capillata (Swallen) Soderstrom, Raddia brasilienses Bertol and Pharus lappulaceus Aublet (Poaceae: Bambusoideae) were collected at Restinga de Jacarepiá, Environment Proctection Area of Massambaba, county of Rio de Janeiro, State of Rio de Janeiro, Brazil, and studied by optical microscope. Leaf anatomy is described in order to contribute to the Poaceae family study. Anatomic features observed in the three studied species such as: midrib with complex vascular system, mesophyll consisting of tabular lobed chlorophyllous elements and fusoid cells, vascular bundles with double sheath, epidermis made up of long cells, short cells, micro-hairs, prickles and silica bodies correspond to the "bambusoid type" of leaf anatomy

Assuntos

RESUMO

Fully developed leaves of Cryptochloa capillata (Swallen) Soderstrom, Raddia brasilienses Bertol and Pharus lappulaceus Aublet (Poaceae: Bambusoideae) were collected at Restinga de Jacarepiá, Environment Proctection Area of Massambaba, county of Rio de Janeiro, State of Rio de Janeiro, Brazil, and studied by optical microscope. Leaf anatomy is described in order to contribute to the Poaceae family study. Anatomic features observed in the three studied species such as: midrib with complex vascular system, mesophyll consisting of tabular lobed chlorophyllous elements and fusoid cells, vascular bundles with double sheath, epidermis made up of long cells, short cells, micro-hairs, prickles and silica bodies correspond to the "bambusoid type" of leaf anatomy.

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RESUMO

OBJECTIVE: To determine the influence of intrapartum antibiotic therapy on blood and secretion cultures of newborn infants suspected of early-onset sepsis. MATERIAL AND METHODS: From August 1995 through July 1996, 69 sequential newborn infants with early-onset sepsis or septic syndrome were included in the study. All of them were followed for the end point: positivity of blood, urine, CSF, tracheal secretion or umbilical catheter cultures. The sample size was figured out to be 17 for each group, for a significant level of 5%. RESULTS: Seventeen mothers were treated with antibiotic. Ampicillin alone or in association with other drugs was utilized in 70% of them. Urinary tract infection occurred in 9 mothers (53%), ammonites in 6, one mother had both and another one had erysipelas. Thirteen newborn infants had positive cultures in the group whose the mothers had not received antibiotic (n=52), none of the 17 newborn infants delivered by the mothers treated with antibiotic had any positive culture (p=0.0164). The relative risk of positive culture in a septic neonate if the mother is not treated with antibiotic is 12 times higher than if the mother is treated with antibiotic. CONCLUSION: The use of intrapartum antibiotic in newborn infants with early-onset sepsis or septic syndrome may cause a negativity of cultural exams, increasing the difficulty of the diagnosis of early-onset neonatal sepsis.