A morphological and ultrastructural study of the paracloacal (Scent) glands of the marsupial Metachirus nudicaudatus Geoffroy, 1803

Morphological and ultrastructural features of the paracloacal glands of Metachirus nudicaudatus are described. Two pairs of glands, one on the right and the other on the left of the anal canal, are formed, each consisting of a major and a minor portion. Their wall is made up of three layers: a mucosal, a muscular and an external capsule. The inner one is a mucosa the epithelium of which contains holocrine cells characterized by lipid droplets and intermediate filaments. The surrounding vascular lamina propria contains flattened tubular apocrine glands whose epithelial cells contain abundant endoplasmic reticulum, prominent Golgi complexes and numerous secretory granules. The middle layer is formed by skeletal striated muscle and the outer (third layer) consists of dense connective tissue. Each gland originates from a single duct. Transverse sections show that each duct, except in the female major gland, is in fact formed by a duct system. One of these ducts comes from the central cavity, lined by holocrine epithelium, and the others result from the branched tubular glands of the lamina propria.

Secretion of salivary glands of the Brazilian termite Serritermes serrifer Hagen & Bates (Isoptera : Serritermitidae)

The salivary glands of termites are composed of several secretory acini connected by ducts. These glands, in the Brazilian termite Serritermes serrifer, were examined through the electron microscope. The ultrastructure of worker salivary acinus revealed central ductule cells and four different types of cells. Cells of type I contain an abundance of electron-lucid vacuoles of various sizes which fuse to form enormous vacuolar structures that fill up most of the cell. Cells of type II are narrow cells in which the secretion is contained in small clear vacuoles of approximately equal diameter. Both of these cellular types have numerous Golgi bodies and rough endoplasmic reticulum. Type III or parietal cells have an apical plasma membrane deeply infolded and lined by microvilli. This type of cell is located in the acinar periphery and occurs in pairs. Cells of type IV are completely filled with electrondense secretion. The secretory granules can be small in some cells or large and similar to fingerprints in others. This is the first report of the occurrence of these spiral or concentric rings of dense material in the salivary gland of Isoptera.

Ultrastructural alterations of choroid plexuses of lateral ventricles of rats (rattus norvegicus) submitted to experimental chronic alcoholism

Adult male rats (Wistar lineage) were alcoholized with sugar cane liquor diluted at 30° GL during 300 days and sacrificed every 60 days in 5 stages. Samples of choroid plexuses of lateral ventricles were collected and examined at transmission electronic microscope to detect possible ultrastructural alterations and to raise possible pathological correlations. Gradual changes were observed in these animals during all the experiment: dilatation and enlargement of cisternae of Golgi complex, dilatation of RER, presence of digestive vacuoles and a large amount of pinocytic vesicles as well as vesicles with electronlucent content throughout cytoplasm, as well as an enlargement of intercellular space between basolateral interdigitation of the cells and of the connective tissue. The changes observed in the epithelium and connective tissue of choroid plexuses specially in 240 and 300 days of treatment are presumably due to a disturbance in hydroelectrolitic homeostasis, contributing to several morpho-functional disturbs of central nervous system. No changes were observed in the control group animals.

Kinetics of spermatogenesis in the Mongolian gerbil (Meriones unguiculatus)

The Mongolian gerbil (Meriones unguiculatus) is a small rodent native to the arid regions of Mongolia and Northeastern China. The present study provides descriptions of both the cellular associations of the seminiferous-epithelium cycle and relative frequencies of stages in the gerbil. Based on the development of the acrosomic system and the nuclear morphology changes using the PAS-H staining technique, the transformation of spermatids into spermatozoa was divided into 15 steps. The first 12 steps were used to identify 12 stages or cellular associations and the other three steps were spread among the first six stages of the cycle of the seminiferous epithelium. The relative frequencies found for stages I through XII were: 13.15; 8.06; 8.98; 6.48; 5.37; 6.71; 7.36; 7.45; 7.27; 5.83; 11.53 and 11.81, respectively. Stage I had the highest frequency while stage V proved the lowest frequency among the XII stages. The pattern of spermatogenesis is similar to those of rodents used as laboratory animals. The present description is the first for this rodent and provides the foundation for a variety of future studies of the testis in this animal. © 2002 Elsevier Science Ltd. All rights reserved.

The thrombocyte aggregation process in the turtle Phrynopys hilarii (Chelonia). An ultrastructural study

This study investigates the thrombocyte aggregation process in the South American fresh water turtle (Phrynopys hilarii) using electron microscopy. Blood was taken from surgically exposed lateral neck vessels often turtles Phrynopys hilarii during the spring and summer seasons, when the mean temperature is 37°C. Blood samples were fixed with Karnovsky solution for processing by transmission electron microscopy. The turtle thrombocytes were spindle-shaped with lobulated nuclei. Prominent vesicles and canaliculi were found throughout the cytoplasm. The cytoplasm organelles showed an agranular endoplasmatic reticulum, Golgi complex near the centrioles and scattered free ribosomes. These cells are similar to bird thrombocytes but distinct from fish and frog thrombocytes. Blood clotting time was 5 min ± 30 sec measured by the Lee and White method. Structural alterations resulting from the aggregation process occurred after activation. Thrombocytes developed numerous filopodial projections, an increased number of vacuoles and changed from spindle to spherical shape. P. hilarii thrombocytes have different morphologic characteristics compared to other non-mammalian vertebrate cells. These cells can participate in the aggregation process, as observed in birds.

Ultrastructure of the salivary glands of Pachycondyla (=Neoponera) villosa (Fabricius) (Formicidae: Ponerinae): Functional changes during the last larval instar

The cells of secretory region of the salivary glands of Pachycondyla (=Neoponera) villosa at the time of enzyme production presents the basal cellular membranes profusely folded and the intercellular junctional membranes present a few enlarged spaces. The rough endoplasmic reticulum and the Golgi bodies shift from being flat and small vesicular cisternae to enlarged vesicular cisternae according to the cell physiological state and characterize an asynchronic cell cycle. Enzymes are released into the lumen by microapocrine secretion. The stage of silk production is detected after a behavioral act, when the nurse worker separates the mature larva. At this time, the salivary gland cells present only one physiological state (synchronized secretory cycle): this state was characterized by basal cellular membrane poorly folded, intercellular junctions presenting some small spaces, rough endoplasmic reticulum compounded by flat cistenae, enlarged Golgi bodies with fibrous material inside and a few secretory vesicles containing silk, which undergo exocytosis. The silk in the lumen shows 2 forms: tactoid and flocculent material.

Ultra-estrutura de glândulas abdominais tegumentares em Oxaea flavescens (Hymenoptera, Andrenidae, Oxaeinae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The ultrastructure of the guinea pig rete testis

The chambers of the rete testis (RT) of guinea pig are lined by a simple epithelium, whose cells are squamous, cubical and columnar in shape. The epithelial cells with distinct shapes were counted and the quantitative analysis of the number of these cells showed relative predominance of cubical cells. The ultrastructural observations showed predominance of membrane interdigitations among the epithelial cells. These cells present common cytoplasmic organelles. The Golgi complex polarity is typical with observation of electronlucent vesicles on the Golgi cis face closely related to rough endoplasmic reticulum (ER) lamellae, mitochondria and large number of polysomes on the Golgi trans face. These related structures present in Golgi area of RT cells suggest secretory activity which maybe occurs in the RT epithelium. Endocytotic process also occurs in the RT and this function probably concerns the uptake of substances and resorption of seminiferous fluid. Apical cilia present in RT epithelium cells are related with fluid transport and perhaps with chemoreception. Presence of spermatozoa portions enclosed into the cytoplasm of some epithelium cells has been refferred to as spermatophagy. The RT complex is mainly supported by loose connective tissue, with collagen fibres and some Leydig cells. Leydig cells are adjacent to the network channels of the septal part of the RT and apparently are able to secrete inside the RT lumen.

Use of a synthetic lethal screen to identify genes related to TIF51A in Saccharomyces cerevisiae

The putative eukaryotic translation initiation factor 5A (eIF5A) is an essential protein for cell viability and the only cellular protein known to contain the unusual amino acid residue hypusine. eIF5A has been implicated in translation initiation, cell proliferation, nucleocytoplasmic transport, mRNA decay, and actin polarization, but the precise biological function of this protein is not clear. However, eIF5A was recently shown to be directly involved with the translational machinery. A screen for synthetic lethal mutations was carried out with one of the temperature-sensitive alleles of TIF51A (tif51A-3) to identify factors that functionally interact with eIF5A and revealed the essential gene YPT1. This gene encodes a small GTPase, a member of the rab family involved with secretion, acting in the vesicular trafficking between endoplasmatic reticulum and the Golgi. Thus, the synthetic lethality between TIF51A and YPT1 may reveal the connection between translation and the polarized distribution of membrane components, suggesting that these proteins work together in the cell to guarantee proper protein synthesis and secretion necessary for correct bud formation during G1/ S transition. Future studies will investigate the functional interaction between eIF5A and Ypt1 in order to clarify this involvement of eIF5A with vesicular trafficking. ©FUNPEC-RP.

Histochemical and ultrastructural evidence of lipid secretion by the silk gland of the sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae)

The silk gland in Lepidoptera larvae is responsible for the silk production used for shelter or cocoon construction. The secretion of fibroin and sericin by the different silk gland regions are well established. There are few attempts to detect lipid components in the insect silk secretion, although the presence of such element may contribute to the resistance of the shelter to wet environment. This study characterizes the glandular region and detects the presence of lipid components in the secretion of the silk gland of Diatraea saccharalis (Fabricius). The silk gland was submitted to histochemical procedure for lipid detection or conventionally prepared for ultrastructural analyses. Lipid droplets were histochemically detected in both the apical cytoplasm of cell of the anterior region and in the lumen among the microvilli. Ultrastructural analyses of the anterior region showed lipid material, visualized as myelin-like structures within the vesicular Golgi complex and in the apical secretory globules, mixed up with the sericin; similar material was observed into the lumen, adjacent to the microvilli. Lipids were not detected in the cells neither in the lumen of the posterior region. Our results suggest that the silk produced by D. saccharalis has a minor lipid content that is secreted by the anterior region together with the sericin.

The role of fibres and the hypodermis in Compositae melanin secretion

Melanins are dark, insoluble pigments that are resistant to concentrated acids and bleaching by oxidising agents. Phytomelanin (or phytomelan) is present in the seed coat of some Asparagales and in the fruits of some Compositae. In Compositae fruits, melanin is deposited in the schizogenous spaces between the hypodermis and underlying fibrous layer. Phytomelanin in Compositae is poorly understood, and there are only speculations regarding the cells that produce the pigment and the cellular processes involved in the secretion and polymerisation of phytomelanin. This report describes the cellular processes involved in the secretion of phytomelanin in the pericarp of Praxelis diffusa, a species with a structure typical of the family. The ovaries and fruits at different stages were fixed and processed according to the standard methods of studies of light microscopy and transmission electron microscopy. Hypodermal cells have abundant rough endoplasmic reticulum and mitochondria, and the nuclei have chromatin that is less dense than other cells. These characteristics are typical of cells that synthesise protein/amino acids and suggest no carbohydrate secretion. The fibres, however, have a dense cytoplasm rich in the Golgi bodies that are associated with vesicles and smooth endoplasmic reticulum, common characteristics of carbohydrate secretory cells. Our results indicate that the hypodermal cells are not responsible for the secretion of phytomelanin, as previously described in the literature; in contrast, this function is assigned to the adjacent fibres, which have an organisation typical of cells that secrete carbohydrates. © 2012 Elsevier Ltd.

Effect of a hyperbolide mastication apparatus for the treatment of severe sleep bruxism in a child with cerebral palsy: Long-term follow-up

Purpose: Sleep bruxism is common among the various oromotor alterations found in individuals with cerebral palsy (CP). Few studies have investigated the use of the mastication device denominated hyperbola (HB) and none was found describing the use of such a device for the treatment of bruxism in children with CP. The aim of the present study was to evaluate the effect of the HB on electromyographic (EMG) activity in the jaw-closing muscles and the reduction in sleep bruxism in a child with CP using surface EMG analysis before and after nine months of treatment. Methods: A seven-year-old boy with severe spastic CP and sleep bruxism was enrolled in this study. The HB was chosen as the treatment option for sleep bruxism in this case because the child did not accept an occlusal splint. The HB has a hyperbolic shape and is made of soft, non-toxic, odorless, tasteless silicone. There are five different sizes of HB manufactured based on the diversity of tooth sizes. This device produces proprioceptive excitation in the dentoalveolar nerve, spindles and Golgi tendon organs. HB has been employed for the treatment of temporomandibular disorder, abnormal oro-dental development, abnormal occlusion, xerostomy, halitosis and bruxism. HB therapy was performed for 5 min six times a day over a nine-week period. Surface EMG of the mandible at rest and during maximum contraction was performed on the masseter and temporalis muscles bilaterally to evaluate electromyographic activity before and after nine months of HB usage. Results: HB usage led to a visible tendency toward the reorganization of mastication dynamics, achieving a marked balance in electromyographic activity of the jaw-closing muscles and improving the child's quality of life. Conclusion: Based on the findings of the present study, this noninvasive therapy may be useful for individuals with cerebral palsy due to its positive effects and low cost, which allows its use in the public health realm. Further clinical studies with a larger sample size are needed to validate these results and allow the development of a new treatment protocol for patients with spastic cerebral palsy. © 2013 Elsevier Ltd. All rights reserved.

NADPH-diaphorase activity in area 17 of the squirrel monkey visual cortex: neuropil pattern, cell morphology and laminar distribution

We studied the distribution of NADPH-diaphorase activity in the visual cortex of normal adult New World monkeys (Saimiri sciureus) using the malic enzyme "indirect" method. NADPH-diaphorase neuropil activity had a heterogeneous distribution. In coronal sections, it had a clear laminar pattern that was coincident with Nissl-stained layers. In tangential sections, we observed blobs in supragranular layers of V1 and stripes throughout the entire V2. We quantified and compared the tangential distribution of NADPH-diaphorase and cytochrome oxidase blobs in adjacent sections of the supragranular layers of V1. Although their spatial distributions were rather similar, the two enzymes did not always overlap. The histochemical reaction also revealed two different types of stained cells: a slightly stained subpopulation and a subgroup of deeply stained neurons resembling a Golgi impregnation. These neurons were sparsely spined non-pyramidal cells. Their dendritic arbors were very well stained but their axons were not always evident. In the gray matter, heavily stained neurons showed different dendritic arbor morphologies. However, most of the strongly reactive cells lay in the subjacent white matter, where they presented a more homogenous morphology. Our results demonstrate that the pattern of NADPH-diaphorase activity is similar to that previously described in Old World monkeys.

Marcadores imunológicos na exposição mercurial na Região Amazônica

Disfunções imunes podem surgir pela combinação entre susceptibilidade genética e fatores ambientais. Existem evidências, em humanos expostos ao mercúrio (Hg), de alterações da resposta imunológica por auto-anticorpos induzidos por Hg. Este trabalho investigou a ocorrência de auto-imunidade induzida por Hgtotal entre indivíduos ribeirinhos da região do Tapajós (Brasília Legal, São Luiz do Tapajós e Barreiras), expostos ao Hgtotal, e da comunidade ribeirinha da região do Tocantins (Panacauera) não exposta ao Hgtotal. No período de junho de 2004 a dezembro de 2006 foram coletadas 236 pares de amostras de cabelo e sangue, nas quais a concentração de Hgtotal no cabelo foi determinada por espectrofotometria de absorção atômica, e no soro, os auto-anticorpos foram analisados por microscopia de imunofluorescência (IF) usando substrato de células epiteliais humanas (Hep-2). Os mais altos níveis de Hgtotal no cabelo foram os de São Luiz do Tapajós (11,24 ± 2,23 μg/g), seguido por Brasília Legal (10,00 ± 0,99) e Barreiras (8,64 ± 1,13), e os mais baixos foram os de Panacauera (2,98 ± 0,20). Em relação à variável sexo, foi observada associação somente em Brasília Legal, com níveis de Hgtotal mais altos no cabelo dos homens. Cerca de 79,65% ribeirinhos do Tapajós e 31,25% da região do Tocantins apresentaram no soro autoanticorpos induzidos por Hg. Os padrões de auto-anticorpos identificados por IF foram: misto (50,96%), nuclear (31,21%), nucleolar (14,65%) e aparelho mitótico/citoplasmático (3,18%), observando-se maior prevalência dos padrões misto e nuclear nas comunidades expostas (p<0,01). Os auto-anticorpos mais freqüentes foram, por ordem de prevalência: NuMa1, PM/Scl, Ssa-Ro, rRNP/Sm, golgi/Ssa/Ro, PCNA, rRNP, Ku, além de outros auto-anticorpos com especificidade ainda não definida. A intensidade de IF (p< 0,0001) foi mais reativa nos ribeirinhos do Tapajós. Análise por regressão logística múltipla indicou que o risco de apresentar auto-anticorpos foi aproximadamente duas vezes maior nos expostos ao mercúrio com faixa etária acima de 50 anos (p>0,01). Finalmente, estudos adicionais são indispensáveis para confirmar a especificidade destes auto-anticorpos induzidos pela exposição mercurial, bem como elucidar os mecanismos imunotoxicológicos da ação do mercúrio sobre o sistema imune humano.