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Biomedical subjects

M E Samar

Publications and source records attributed to M E Samar.

At least 19 recordsLinked to original sources
PubMed2001

[Ultrastructural behavior of interstitial cells innervation during the differentiation of the chick embryo ovary cultured with 17-beta-estradiol].

In a previous work we demonstrated the relationship between nerve fibers and nerve endings and interstitial cells (estrogen-producing cells) from the atrophic right ovary and the medulla in the left functioning ovary during embryogenesis in the chick, in ovo. Besides, the local production of neurotrophins by steroidogenic cells is probably involved in the control of ovarian innervation. The objective of the present study was to analyze ultrastructurally the innervation during the differentiation of chick ovary cultured with 17-beta-estradiol. Explants of right and left ovaries from seven to nineteen days in ovo development were cultured separately for 4 days in MEM (controls) or in the presence of 17-beta-estradiol (problems). In controls the electron microscopic examination of the innervation explants from chick embryo ovaries revealed that the interstitial cells are well innervated. Nerve fibres and nerve endings were observed in close contact with steroid-producing cells, a similar pattern of innervation that those of the fifteen days ovaries in ovo development. Problems cultured from seven days showed nerve fibres and nerve endings at difference to controls. These results in vitro suggest that innervation of the ovaries is controlled by indirect mechanism via the hypothalamic-pituitary system and local production factors. More experiments are necessary to confirm this results.

Animals↗
PubMed2000

Avian minor salivary glands: an ultrastructural study of the secretory granules in mucous and seromucous cells.

Ultrastructural descriptions in birds are scarce thus, in this study we have characterized the secretory granules of mucous and seromucous cells from the palatine and lingual salivary glands of birds with different diets. The samples were taken from the tongue and palatine mucosa of chicken (Gallus gallus), quail (Coturnix coturnix), chimango (Milvago chimango) and white heron (Egretta thula). The samples were processed for observation by transmission electron microscopy (TEM) employing 4% Karnovsky solution for fixation. The most noteworthy finding was the heterogeneous ultrastructural appearance of the secretory granules. Differences in substructure were found between the four species, between the palatine and lingual glands in the same species and even within the same acinus and the same cell. At variance with other authors, these differences cannot be attributed to the type of fixative solution used taking into account that all the samples were processed in the same way. Previous histochemical studies have shown the presence of sulfated and non sulfated glycoconjugates in these glands which can be associated to the maturation of the granules. These granules are probably representative of peculiar storage of the secretory products that would give rise to a heterogeneous and complex ultrastructural pattern of granules in the mucosa and seromucosa cells of these avian species.

Animals↗
PubMed1999

Histochemical study of magellanic penguin (Spheniscus magellanicus) minor salivary glands during postnatal growth.

The histological and histochemical features of the minor salivary glands during postnatal development have been generally associated with the type of food ingested. However, recent studies support the fact that these salivary glands develop independently of the diet; in fact, minor salivary glands have similar morphological and histochemical characteristics in adult individuals of species with different diet regimens. Thus, the aim of this study was to characterize the developmental morphology of the penguin minor salivary glands and to contrast them with minor salivary glands of other species. The tongue, palatine, and mouth cavity (bottom) minor salivary glands of newborn, 1- to 20-day-old, and adult magellanic penguins were studied with hematoxylin-eosin, periodic acid-Schiff, alcian blue, toluidine blue, and lectin histochemistry. Minor salivary glands were present at all ages, although they were only moderately developed in animals less than 15 days old. After this age, glands were abundant in all age groups; in addition, cells from the glandular epithelium were functionally mature and secreted mucins. Nevertheless, in newborn to 15-day-old penguins, mucins were located only at the apical cytoplasm of mucous cells. In all ages, mucous cells displayed periodic acid-Schiff-positive, alcianophilic, and metachromatic reactions; among mucous cells, other orthochromatic cells appeared interspersed. From 15 days on, histochemical reactions became more intense until adulthood, and the cytoplasm of secretory cells was filled with glycoproteins and sulfomucins. Moreover, lectins bound to different oligosaccharides in mucous cells, depending on the stage of maturation of the glands. In conclusion, penguin minor salivary glands are already present at birth, and show progressive and quantitative increases in mucous secretion during postnatal development. These changes are necessary not only for nutrient ingestion, but also for nonimmune protection of the buccal cavity.

Age Factors↗
PubMed1997

Structural and cytochemical modifications in the lingual glands of the newborn chicken irradiated with He-Ne laser.

Despite the increasing and successful use of laser in Medicine and Odontology, the possible iatrogenic and otherwise deleterious side effects of this radiation remain mostly unknown. In previous studies, it was shown that both the embryonic and the post-hatched chicken constitute reliable experimental models for this type of studies. Hence, the purpose of the present work was to analyze the structural and cytochemical alterations of the lingual glands of the newborn chicken irradiated with low energy He-Ne laser. This laser produced regressive structural changes of the glands towards the embryonic stage as well as hyperplasia of the reserve glandular basal cells. Furthermore, a decrease in the glycoprotein content and a rise in the sulphated glycosaminoglycans were also found. These results corroborate the pathogenic effects of the He-Ne- laser on the experimental model employed and, at the same time, emphasize the importance of considering, regarding clinical applications, possible previous neoplastic alterations as well as adverse reactions which might appear once laser therapy has been installed.

Animals↗
PubMed1996

[Design of a thermic detection system applied to chick embryonated eggs irradiated with infrared rays].

Infrared radiations are widely used in medical therapeutics. It has been argued that the doses and the periods of time employed in experimental animals are higher than those used in clinic. Thus, we considered of interest to analyse aspects of dosimetry and thermic effects of infrared rays with current methods in medical practice, using the in ovo chick embryo as a model of easy control. To this end we designed a system to measure temperatures and their acquisitions and software for its handling. The system consists of: a) thermic points: thermocuples or termistores adaptable to the experimental requirements and calibrated with a greater precision within a range of ten degrees around the incubation temperature; b) acquirer circuit of thermic data (hardware): it generates a time base that varies with the thermic sensor. Software: the PC XT or AT detects changes in the time base by means of a programs' in a Turbo Pascal; c) storage and analysis of data allows, through a menu (expansibles) the scale selection, time of program data to be acquired, storage and recovery of the diskette information and graphic impression; d) chick's embryonated eggs. This system allows to measure temperature distribution in small physical spaces with little disturbance of the system to be measured in irradiated bodies, to analyse variations of the temperatures in time and to secure a greater confidence and automatism to obtain the required data.

Animals↗
PubMed1995

[Morphological evaluation of intercellular junctions in the ovary of chick embryos: action of steroid and gonadotropic hormones in vitro].

Variations of the intercellular junctions of the germ and epithelial cells of the ovarian epithelium produced by gonadotropic and esteroid hormones were determined on ovaries of the chick embryo at 7 days of development. Explants of right and left ovaries were cultured without (control) or with hormones eddition (experimental) for 4 days. Cultures were processed for their ultrastructural study. In both control ovaries the union complexes were similar to those identified in ovo. Under the action of 17 beta-estradiol, an increase and a greater development of adherens junctions was observed in the left ovary; in the right ovary, adherens junctions diminished by action of 17 beta-estradiol. The response of the left ovary to progesterone and testosterone was similar to that seen with the estrogen. No changes were observed in the right gonad. A disminution of intercellular junctions was produced in both ovaries under the action of FSH. The changes produced by LH and hCG were similar to those find in the left ovary with the estrogen, consisting of an increase of the union complexes, mainly of the adherens type. These results indicate that steroid and gonadotropic hormones act by modifying intercellular junctions and would participate in the processes of growth and atrophy that occur in the ovaries of the chick embryo.

Animals↗
PubMed1993

Embryogeny of human labial glands: a structural, ultrastructural and cytochemical study.

A histochemical study of labial glands was performed to compare the different stages of differentiation with those of lingual glands previously studied. Labial glands of 8 to 32 week old human fetuses were analyzed with Hematoxylin/eosine, PAS, Cason, Alcian blue, Toluidine blue, methenamine/silver, TEM and Ruthenium red techniques. At 8-10 weeks various differentiation phases of cell cords originated in the epithelium of the labial mucosa were observed. Acinar buds had PAS positive, alcianophilic and metachromatic material in the lumen of 14 week labial glands. The excretory ducts featured similar characteristics. At 24 weeks groups of mucous and seromucous acini were identified and the mucosubstances increased in the 32 week old fetuses. These results show that the labial glands are histophysiologically differentiated at an earlier stage of development (14 weeks) as compared to lingual glands (20 weeks). However, mucosubstance production would begin during the early phases of embryogenesis for both labial and lingual glands.

Cell Differentiation↗
PubMed1993

Prenatal development of human palatine glands: a structural and cytochemical study.

The histogenesis of the salivary glands was structurally and cytochemically studied in human embryos and fetuses during the period of 8 to 32 weeks of intrauterine life. Glandular buds appeared at about 12 weeks of embryonic development. The rounded distal ends of the epithelial cords and neighbouring mesenchyma showed small and abundant PAS positive and alcianophilic granules. At age 14 weeks the secretory end pieces and the duct system were seen at different morphologic and structural stages of a differentiation. Mucous acini with scanty mixed acini predominated and serous acini appeared occasionally. From 20 to 24 weeks the mucous acini stained with toluidine blue featured different degrees of metachromasia even in the case of cells of the same acinus. In the ducts it was also possible to identify metachromatic cells intermingled with basophilic cells in the epithelial coat. These findings suggest that the palatine glands present typical histophysiological material from 14 to 20 weeks. The presence of PAS positive, alcianophilic and metachromatic secretory substance in the acinar lumen and the luminal content of ducts suggests that mucin secretion begins during intrauterine life.

Embryonic and Fetal Development↗
PubMed1992

Effects of He-Ne laser irradiation on chick embryo mesonephros.

A study on the effects of He-Ne laser irradiation on glomeruli and renal tubules of the chick embryo mesonephros at 7 days of in ovo development was made. To this purpose, He-Ne laser irradiation (potency: 5 mW, wavelength: 632.8 nm) was beamed for 5 minutes through a window opened in the egg shell, and the eggs were maintained aseptically for 24 h in an incubator. Mesonephros were dissected out and processed for hematoxylin/eosin, periodic acid-Schiff, and Alcian blue at pH 2.5 and 1.0, toluidine Blue at pH 3.8. In controls, the glomeruli were formed by coiled capillaries with a homogeneous basement membrane, the proximal tubules presented a high cubic epithelium with acidophilic cytoplasm and a developed brush border. Distal and collecting segments were lined by cubic epithelium. An alcianophilic and PAS-positive reaction stood out at the membrane coats of the proximal tubules and tubular and glomerular basement membranes. No glomerular alterations were observed during the experiment. However, there was a marked enlargement of the tubular interstitium, with edema and lymphohistiocytic inflammatory infiltration. Some tubular cells desquamated to the lumen. Other cells presented a raveled apical surface. Some nuclei were dispersed out, and mixing with chromatin, formed diminutive granules. Pyknotic nuclei were seen occasionally. Epithelial necrosis and cytoplasmic debris in the lumen were also noted. For mucins, some zones showed brush border coats of the proximal tubules as discontinuous.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Structural changes induced by He-Ne laser on the chick embryo ovary.

UNLABELLED: The morpho-histochemical alterations that occur in the chicken ovary at 7 days of incubation after irradiation with He-Ne laser of a potency of 5 mw and at a wavelength of 632.8 nm were studied. The embryos were irradiated for 5 minutes through a window opened in the eggshell and aseptically maintained in incubator for 24 hours. The gonads were dissected out and processed for the following techniques: H/E, PAS, alcian blue, and toluidine blue. CONTROLS: The ovaries were formed by a germinative or superficial epithelium, with germ and epithelial cells, and by primary sex cords compressed between them, although separated by a reduced stroma. The cords contained germ cells The surface coat of the germinative epithelium presented a thin layer of PAS positive, alcianophilic at pH 25 and orthochromatic material. Basement membranes and intercord extracellular substance were also PAS positive. PROBLEMS: Disorganization of the tissue structure was well manifest in irradiated gonads, accompanied by negativization of the histochemical reactions. A lymphocytic infiltration was also found. No structural alterations were observed in germ or epithelial cells. It is concluded that laser radiations would act producing decrease of the mucosubstances associated to the plasma membrane and basement membrane. They would also provoke the appearance of an inflammatory mononuclear infiltration.

Animals↗
PubMed1991

Evolution of germinal epithelium in the chick ovary during embryogenesis.

In previous works we showed a probable relationship between plasma membrane and its differentiations in ovary epithelium with maturation of the left ovary in chick embryo. To elucidate this aspect a cytochemical and ultrastructural study of the germinal epithelium from 7 to 19 days-old chick embryos was performed. Cytochemical and ultracytochemical techniques for mucosubstances localization and transmission electron microscopy were used. At 7 days the epithelium of right and left ovary showed epithelial cells with microvilli and junctional complexes. Irregular folds and projections appeared in the germ cells. Both cell types possessed a coat with a light reaction in the right gonad and more intense in the left one when they were stained with Alcian blue, PAS or Ruthenium Red. From 11 to 19 days, in the left ovary epithelium the layers of cells were increased and presented discontinuous basement membranes and absence of cell projections. On the contrary, in basal and germ cells these structures were increased. The mucosubstances increased from the 15th day. At this time the right ovary showed a simple epithelium with cells without projections. The germ cells disappeared in this ovary and a marked decrement of mucosubstances was observed. These results indicate that it exists a direct relationship between cellular morphogenesis and the mucosubstances of membranes. These substances may play a special role in the cellular migration of the left ovary since they were not detected in the right gonad which suffers regression and embryonic atrophy.

Animals↗
PubMed1991

Cytochemical variations of human von Ebner's glands.

Human von Ebner's glands were analyzed during fetal and childhood development, and adultness, with the purpose of observing possible age-related cytochemical changes. Tongues from 8-38 weeks-old fetuses, samples of the lingual V from newborns, 8 to 14 years-old children and adults aged 20 years and older were used. H/E, and techniques for mucosubstances (PAS, PAS/amylase, PAS/sialidase, methenamine-silver, Alcian blue at pH 2.5 and 1.0, and Toluidine blue at pH 3.8) were employed. Between 16 and 20 weeks acini and ducts in the process of formation were identified, being the parenchyma completely developed at 24 weeks. The morphology of glands from newborns consisted of basophilic and periodate-negative serous acini. In infants secretory cells contained PAS positive apical granules that were sensitive to sialidase, periodate-reactive and slightly metachromatic. These characteristics were increased with age. Besides, in adults, the apical cytoplasm of the adenomerous and the luminal content were also alcianophilic. The cytochemical variations observed indicates that human von. Ebner's glands are composed of cells of the seromucous type that contain sialomucins and sulphomucins.

Adult↗
PubMed1991

Interstitial cells of the ovaries of the chick embryo: ultrastructural aspects of their innervation.

In a previous work we demonstrated that germ and epithelial cells of the atrophic right ovary and of the medulla in the left functioning ovary undergo regression while interstitial cells are preserved. The objective of the present study was to analyze the relationship between nerve fibers and nerve endings and interstitial cells from both ovaries during embryogenesis in the chick. To this purpose, left and right ovaries from embryos of 7 to 19 days of development were processed for ultrastructural study and ultracytochemical determination of acid phosphatase. At 7 days, isolated interstitial cells were found in the central region of both ovaries, containing SER, Golgi apparatus, mitochondria with tubular cristae and abundant lipidic vacuoles. Nerve fibers and nerve endings were scarce. From the 11th day, interstitial cells were found grouped in the right ovary and in the medulla of the left one, and were related to nerve bundles surrounded by Schwann cells. The nerve ending, in close contact with the membrane of interstitial cells, contained mitochondria, microtubules and small and big vesicles, some with an electro-dense content. This relationship between interstitial cells and nerve endings and fibers was more frequent from the 15th day. The activity of acid phosphatase localized in germ and epithelial cells presented a more intense reaction in the right ovary and in the medulla of the left ovary at 15 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗