Estudo morfológico e radiológico sobre a comunicação entre a articulação interfalangeana distal e a bolsa do osso navicular em eqüinos (Equus caballus, L., 1758)

Objetivou-se neste estudo verificar radiográfica e morfologicamente a existência de comunicação entre a bolsa do osso navicular (BN) e a articulação interfalangeana distal (AID), estabelecendo sua freqüência, sua forma e identificação das estruturas anatômicas envolvidas no processo. Para tanto, foram utilizados membros torácicos e pélvicos de 16 animais vivos, sendo 8 animais jovens e 8 animais adultos. Contraste iodado era injetado na BN dos membros direitos e na AID dos membros esquerdos. em seguida, realizavam-se radiografias em projeções látero-medial ou médio-lateral, dorsopalmar ou dorsoplantar, para a constatação de possível comunicação entre as estruturas em questão, que, posteriormente, seriam identificadas por meio da técnica de dissecação. Não foram observadas comunicações entre as estruturas em questão ou qualquer outra na porção distal dos membros, porém, em dois membros torácicos, constataram-se variações morfológicas nas extremidades laterais da BN, caracterizadas por projeções que se estendiam até o terço proximal da falange média, sendo mais pronunciada na face lateral que na medial.

Estudo morfológico e radiológico sobre a comunicação entre a articulação interfalangeana distal e a bolsa do osso navicular em peças anatômicas de eqüinos (Equus caballus, L. 1758)

Objetivou-se neste estudo verificar anatômica e radiograficamente a existência de comunicação entre a bolsa do osso navicular (BN) e a articulação interfalangeana distal (AID), estabelecendo sua freqüência e forma e identificando as estruturas anatômicas envolvidas no processo. Desta forma, foram utilizadas 140 peças anatômicas de membros torácicos e pélvicos de eqüinos. Com o auxílio de fluoroscópio, foi injetada uma mistura de contraste iodado, Neoprene látex e corante na BN dos membros direito e na AID dos membros esquerdos, com subseqüentes exposições radiográficas. Constatadas comunicações, identificavam-se as estruturas e os locais envolvidos, mediante técnica de dissecação. Verificou-se, em duas observações, comunicação entre a BN e a AID, após injeção de contraste iodado, látex e corante na bolsa do osso navicular, sendo um no membro torácico direito (MTD) e outro no membro pélvico direito (MPD). Comunicação entre a AID e a bainha do tendão do músculo flexor profundo do dedo (BTMFPD) ocorreu em uma peça, pertencente ao membro torácico esquerdo (MTE). Comunicação entre a BN e a BTMFPD foi observada na peça de um membro torácico direito. Variações morfológicas nas extremidades laterais da BN, constituindo projeções que se estendiam até o terço proximal da falange média, sendo mais pronunciada na face lateral do que na medial, ocorreram em cinco membros. Mediante a administração de contraste iodado, látex e corante na AID, nenhuma comunicação foi observada entre a AID e a BN.

Variations in tree community composition and structure in a fragment of tropical semideciduous forest in southeastern Brazil related to different human disturbance histories

In an area of tropical seasonal semideciduous forest, the soil characteristics, floristic composition, physiognomic structure, and the distribution of three regeneration and three dispersal guilds were studied for four stands within the forest that had documented histories of varying degrees of human disturbance. The aim was to study forest regeneration in areas of preserved forest and secondary forest, with parts of both types of forest experiencing either 'intensive' or 'occasional' cattle trampling. The study was carried out in the Sebastiao Aleixo da Silva Ecological Station, Bauru, São Paulo State, Brazil. Two stands were called 'secondary' because they corresponded to forest tracts that were felled and occupied by crops and pastures in the past and then abandoned to forest regeneration ca. 40 years before this study. The other two stands, called 'preserved', corresponded to areas of the fragment where the forest has been maintained with only minor human impacts. The arboreal component of the tree community (diameter at breast height or dbh greater than or equal to 5 cm) was sampled in 20 plots of 40 m x 40 m, and the subarboreal component (diameter at the base of the stem or dbs < 5 cm and height greater than or equal to 0.5 m) in subplots of 40 m x 2 m. Physiognomic features, such as canopy height and density of climbing plants, were registered all over a 5 m x 5 m gridline laid on the sample plots. Soil bulk samples were collected for chemical and textural analyses. Most detected differences contrasted the secondary to the preserved forest stands. The soils of the secondary stands showed higher proportions of sand and lower levels of mineral nutrients and organic matter than those of the preserved stands, probably due to higher losses by leaching and erosion. Compared to the secondary stands, the preserved ones had higher proportions of tall trees, higher mean canopy height, lower species diversity, higher abundance of autochorous and shade-tolerant climax species, and lower abundance of pioneer and light-demanding climax species. Despite the high proportion of species shared by the preserved and secondary stands (108 out of 139), they differed consistently in terms of density of the most abundant species. on the other hand, the secondary and preserved stands held similar values for tree density and basal area, suggesting that 40 years were enough to restore these features. Effects of cattle trampling on the vegetation were detected for the frequency of trees of anemochorous and zoochorous species, which were higher in the stands under occasional and intensive cattle trampling, respectively. The density of thin climbers was lower in the stands with intensive trampling. (C) 2004 Elsevier B.V. All rights reserved.

AN ANATOMICAL STUDY OF THE LATEROTRIGEMINAL VENOUS SYSTEM

The middle cranial fossa of 100 cadavers were dissected under stereoscopic loupe in order to identify and systematize the venous vessels located along the lateral margin of the trigeminal cave. The author found that at the sensitive root and trigeminal ganglion level a dural venous canal was present in most individuals examined and that the upper side of this canal communicated with the superior petrosal sinus. However, at the level of the lateral border of the intracranial segment of the mandibular nerve, venous lacunae were found to prevail, and these lacunae communicated with several other venous formations in the peritrigeminal region. The author concludes that the venous vascularization of this area constitutes a major risk in surgical interventions made in the middle cranial fossa. In addition, it is a relevant factor in the hemodynamics of the intracranial circulation.

The taxonomy and morphological and anatomical differentiation of populations of Leiothrix crassifolia (Eriocaulaceae)

The morphological and anatomical leaf and scape differentiation of Leiothrix crassifolia is analysed and classified into seven types (I, II, III, IV, V, VI, Vn). The species has a relatively wide distribution in the campo rupestre of Minas Gerais in Brazil. Variation in the isolated populations on different mountain ranges is complex, does not follow a clear geographical pattern, and defies taxonomic classification. L. nubigena and L. obtusifolia are included in L. crassifolia.

Physiological and genomic variations in rice cells recovered from direct immersion and storage in liquid nitrogen

The use of cryoprotectants and slow cooling rates are routine procedures for the cryopreservation of plant cell lines. However, our results with rice (Oryza sativa L,, ev. Taipei 309) show that calli can be cryopreserved by direct immersion and stored in liquid nitrogen without any cryoprotection, the efficiency of recovery using this method, as well as a conventional method was generally increased with a previous abscisic acid (ABA) treatment. Following cryopreservation, calli demonstrated some differences with respect to unfrozen calli of the same lines, Thus, resistance to freezing stress (- 20 degrees C for 2 h) increased significantly in all lines tested, irrespective of their pre-incubation with ABA, Calli that had been directly stored in liquid nitrogen also demonstrated a higher competence for genetic transformation than their unfrozen counterparts, as indicated by the transient gene expression levels obtained after particle bombardment, These differences might lead to further biotechnological applications, A genetic analysis of amplified DNA polymorphisms was performed with three independent lines that had been subjected to four combinations of ABA treatment and direct immersion in liquid nitrogen, At the loci screened with the randomly amplified polymorphic DNA (RAPD) markers tested, the genetic variations among lines and among calli of the same line appear to bd more related to tissue-culture-induced somaclonal variation than to cryoselection.

ANATOMICAL STUDY OF THE OPOSSUM (DIDELPHIS-ALBIVENTRIS) EXTRAOCULAR-MUSCLES

The anatomy of the extraocular muscles was studied in 10 adult opossums (Didelphis albiventris) of both sexes. Eight extraocular muscles were identified: 4 rectus muscles, 2 oblique muscles, the levator palpebrae superioris and the retractor ocular bulbi. The rectus muscles originate very close one to another between the orbital surfaces of the presphenoid and palatine bones. These muscles diverge on the way to their insertion which occurs at about 2 mm from the limbus. The levator palpebrae superioris originates with the dorsal rectus and is positioned dorsally in relation to it. The retractor ocular bulbi forms a cone which embraces the optic nerve and is located internally in relation to the rectus muscles. The dorsal oblique originates on the presphenoid bone and after a tendinous trajectory through a trochlea on the medial wall of the orbit, inserts into the ocular bulb. The only muscle arising from the anterior orbital floor is the ventral oblique. The main nerve supply for these muscles is the oculomotor, except for the dorsal oblique which is innervated by the trochlear nerve, and the lateral rectus which is innervated by the abducens nerve. The retractor ocular bulbi receives branches from the inferior division of the oculomotor nerve and some branches from the abducens nerve.

Morpho-anatomical aspects of Paepalanthus hilairei Koern (Eriocaulaceae) from Serra do Cipo MG

The morphological characteristics of seedlings and the anatomical characteristics of vegetative organs and floral scape of P. hilairei (Eriocaulaceae) were analyzed to investigate the ecological and taxonomic implications for the species. P. hilairei is a perennial plant with an aerial stem and it grows in recently decomposed stony, sandy soils of the Serra do Cipo, in the State of Minas Gerais, Brazil. It is found both on wet and dry soils, exposed to constant winds, high light intensities and extreme daily fluctuations of temperature. The results show that the seeds have operculum and the initial seedling development stages are the same for other Eriocaulaceae. During the germination period, the undifferentiated axis of the embryo becomes apparent. The observation of the development of this axis, shows first, the growth of the leaves and later that of the adventitious root. Attention is focused on the apical stem region which presents sterelis lateral branching with adventitious roots in its base which will develop into paraclades (system of florescences). Both of them rise out of the pericycle and characterize its vegetative growth. The occurrence of a special leaf substomatal chamber may be related to an efficient protection for the gaseous exchange and may be considered an important characteristic of the Eriocaulaceae.

Morphological and anatomical studies of the seedes and seedlings of Eucalyptus citriodora and E. maculata

Morphological and anatomical aspccts of secds and seedlings of Eucalyptus citriodora Hook and E. maculara Hook were studied in detail and faund to be e.xtremely similar. However. the external characteristics of the secd. the secd coat anatomy and sorne features of the scedlings appeared to be very useful in the identificatian of these two economica11y important species.