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J Illanes

Publications and source records attributed to J Illanes.

10 recordsLinked to original sources
PubMed2001

Antiangiogenic effect of betamethasone on the chick cam stimulated by TA3 tumor supernatant.

Tumor growth is the result of combined cell proliferation overwhelming cell death and neoangiogenesis. This report shows CAM angiogenesis promoted by TA3 tumor supernatant with or without low dosis of betamethasone (Minimal antiangiogenic concentration: beta-MAAC). Methylcellulose discs instilled with 10 microliters of beta-MAAC (0.08 microgram/ml), 10 microliters of tumor supernatant (TA3ts), 5 microliters beta-MAAC + 5 microliters TA3ts, and 10 microliters of PBS as control were implanted in host chick eggs. On day 12, the grafts were removed, photographed and fixed. Sections were stained in parallel, one and three with hematoxylin-eosin, and section two by the Tunel method. The number of vessels was evaluated in a microscopic field of the CAM (2250 micron 2). The results show that beta-MAAC produced a significant inhibition of neovascularization in comparison to that observed in controls (P < 0.0025; Student t-Test). Discs instilled with TA3ts produced an intense stimulation of angiogenesis in contrast, when discs were instilled with 5 microliters of beta-MAAC + 5 microliters of TA3ts the angiogenesis was significantly inhibited (P < 0.001). The results show that effective antiangiogenic doses of betamethasone are in the range of 10(-7) M, (probably a genomic mediated action) and that this effect of low concentration may have clinical applications.

Allantois↗
PubMed2000

Histochemical detection of sugar residues in lizard teeth (Liolaemus gravenhorsti): a lectin-binding study.

The structural diversity of the many oligosaccharide chains of surface glycoconjugates renders them likely candidates for modulators of cell-interactions, cellular movements, differentiation, and cellular recognition. A selection of different lectins was used to investigate the appearance of cellular distribution and changes in sugar residues during tooth development in the polyphyodont lizard, Liolaemus gravenhorsti. Lectins from three groups were used: (1) N-acetylgalactosamine specificity: BS-1, PNA, RCA-120; (2) N-acetylglucosamine specificity: ECA; and (3) fucose specificity: UEA 1 and LTA.. Digital images were processed using Scion Image. Grayscale graphics in each image were obtained. The lectins used showed a strong, wide distribution of the L-fucose and N-acetylgalactosamine at the cell surface and in the cytoplasm of multinucleate odontoclast cell, while mononuclear odontoclast cells showed no binding, suggesting some roles that the residues sugar might play in the resorption of dentine or with multinucleation of odontoclast after the attachment to the dentine surface in this polyphyodont species. Further studies must be planned to determine the specific identities of these glycoconjugates,and to elucidate the roles played by these sugar residues in the complex processes related to odontogenesis in polyphyodont species.

Acetylgalactosamine↗
PubMed1999

Microscopic and histochemical study of odontoclasts in physiologic resorption of teeth of the polyphyodont lizard, Liolaemus gravenhorsti.

Using tartrate-resistant acid phosphatase (TRAP), we examined the cytodifferentiation of odontoclast cells in resorbing areas of dental tissues during the replacement of teeth in a polyphyodont lizard, Liolaemus gravenhorsti. We also report, by means of Lectin-HRP histochemistry, the distribution pattern of some specific sugar residues of TRAPase-positive cells. For detection of TRAPase activity, the azo dye-coupling technique was used. Lectin binding sites were demonstrated by means of specific HRP-lectins. The process of tooth resorption was divided into four stages: 1) preresorption-the wall of the dental pulp is covered with an odontoblast layer, and no TRAP-positive cells are in the dental pulp; 2) early resorption-TRAP-positive multinucleate odontoclasts are present on the dental wall, but the rest of the pulp surface is still covered with an odontoblast layer; 3) later resorption-the entire surface of the pulp chamber is lined with multinucleate odontoclasts; and 4) final resorption-the tooth has been totally resorbed. Odontoclasts are usually detached from the resorbed surface, and show signs of degeneration. Of the six lectins used, PNA, ECA, and UEA-1 bind to multinucleated but not mononuclear cells. All the remaining lectins, BS-1, RCA(120), and LTA showed no binding to any cells of the teeth. The significance of saccharidic moieties such as acetyl-galactosamine, acetyl-glucosamine, and fucose sugar residues is difficult to ascertain. Perhaps these oligosaccharides might be borne on molecules associated with odontoclastic resorption or associated with multinucleation of odontoclasts after attachment to the dentine surface.

Acetylgalactosamine↗
PubMed1999

Ethanol effect on the chick embryo ossification: a macroscopic and microscopic study.

This study attempts to analyze anomalies in avian embryos induced macroscopically and microscopically when exposed to ethanol (EtOH) during the first stages of development. Fertilized chicken eggs were employed in this study. The eggs were incubated at 37.8 degrees C. Some of the eggs were treated on day 0 with EtOH (20%, 40% and 60%) by instillation in the air sac. The control group was instilled with 0.1 ml of NaCl at 0.9%. Other eggs were treated on the 4th post-incubation day, employing the same methodology. The embryos in both groups were removed from the eggs on the 11th incubation day and examined using a dissecting binocular microscope. After macroscopic analysis, the samples obtained were fixed in 10% formol, photographed and processed according to common histological techniques and the Picrosirius method. Embryos treated with EtOH demonstrated a significant weight decrease. Microscopic analysis by means of the Picrosirius method revealed that the intra-membranous ossification process presents less development, and therefore there was less type I collagen in trabecular bone in the embryos post-exposure to EtOH with respect to the control.

Abnormalities, Drug-Induced↗
PubMed1996

Hatching gland cells of trout embryos as the target of positional information.

HGCs were found in the head epidermis, yolk sac and pharynx epithelium of trout embryos. These cells usually appear in clusters, closely related positionally to neighbouring cells. The differentiation and specialization of HGCs seem to be mainly dependent on cell-cell interactions, which provides, in part, the positional information necessary for the cells to differentiate and localize in the appropriate place. The final secretory process is the result of a sequence of events by which the maturation of enzymatic granules occurs. The electron-density of the granules varies according to the proximity of the secretory stage. Exocytosis of the secretory granules were observed. After secretion, each HGC undergoes cellular death by apoptosis (programmed cell death).

Animals↗
PubMed1995

[Experimental induction of abnormalities by the instillation of ethanol in embryonated eggs of chickens (Gallus gallus)].

The teratogenic effect of alcohol on chick embryos has been confirmed by many investigators. However, how this occurs is unknown. The aim of this study was to establish a teratogenic pattern of alcohol effects, on the first stages of development in avians. Fertilized eggs were infused through the air space of the shell on day 0, with ethanol in concentrations of 20%, 40% and 60%. The control group was infused with 0.1 ml of NaCl at 0.9%. At a second stage, the eggs were treated on the 4th day of incubation, using the same method. In both groups the eggs were removed on the 11th day of incubation. The teratological manifestations that appeared more frequently were evisceration, haemorrhagic embryos, oedema, cranial deformities, lack of eyes, and umbilical hernia, showing every embryo a clear reduction in size and body weight.

Abnormalities, Drug-Induced↗
PubMed1986

Odontogenesis and amelogenesis in interacting lizard-quail tissue combinations.

In this study we examined the possible inductive role of the dental papilla from polyphyodont lizard tooth germs. Flank skin sheets of quail ectoderm enzymatically separated from dermal tissue were recombined with lizard tooth papillae and placed on semisolid medium and cultured for 2 days. Subsequently, the recombinants were removed and placed on the chorioallantoic membrane of chick hosts and incubated for 6 days. After this period of 8 days in explant, control tissues differentiated according to their own phenotypes. Lizard dental papilla alone differentiated as fibroblasts. Quail flank skin ectoderm differentiated into epithelial sheets. Intact lizard tooth buds developed into teeth with dentine and incipient enamel. In the best experimental recombinants, advanced and relatively well-constructed teeth were observed, with clear indications of hard tissue deposition in association with quail epithelium. The results show that mesenchyme of the adult lizard dental papilla and embryonic quail ectoderm of heterotopic origin are capable of carrying out the complex sequence of morphogenetic interactions involved in normal odontogenesis.

Amelogenesis↗
PubMed1983

Ultrastructural aspects of dental tissues and their behavior in xenoplastic association (lizard quail).

Ultrastructural characteristics of tooth buds of the polyphyodont adult lizards Liolaemus tenuis and Liolaemus gravenhorsti have been elucidated. Xenoplastic combinations of lizard whole tooth buds and neural crest cells from embryos of the quail Coturnix coturnix japonica have been cultured in vitro. Mesenchymal cells (preodontoblasts) of lizard teeth early develop filopodia that contact the basal lamina. Fragments of quail neural crest isolated by dissection were recombined with isolated lizard tooth buds and cultured for 84 hours in dishes kept in an incubator at 37.8 degrees C in air. Some identifiable quail cells in these recombinants developed a cytoplasmic extension like that of an odontoblastic process. These results suggest that lizard tooth rudiments already determined for tooth development produce some non-species specific transmissible constituents which are capable of inducing quail cranial neural crest cells to express certain dental characteristics (odontoblastogenesis) not expressed in their normal development in vivo.

Animals↗
PubMed1980

In vitro differentiation of tooth buds from embryos and adult lizards (L. gravenhorsti): an ultrastructural comparison.

It is well established that the capacity for teeth to differentiate "in vitro" depends upon: a) the age of the embryonic rudiments at the time of excision and b) the number of cells within each tissue type which are capable of differentiating into organ culture. This paper studies ultrastructural aspects of tooth buds grown in vitro from lizard embryos and compares these characteristics with those observed in dental germs grown in situ in older lizard embryos. Moreover, we report the self-differentiation in vitro dental tissues from adult lizard and compare this phenomenon with the main features of a morphogenetic field. Our results suggest that approximately in the first third of gestation in L. gravenhorsti the dental buds has already acquired the capacity for self-differentiation in vitro. The ultrastructural observations show that there are no significant differences between odontoblasts and ameloblasts in situ and in vitro. The tooth from "adult lizards," isolated by combined microsurgical and enzymatic procedure and cultured in semisolid-liquid medium were also able to differentiate teeth. This phenomenon implies that self-differentiation is not rigidly determined, and that in these animals the tooth tissues represents a continuous morphogenetic field throughout the animal's life. This property is intrinsic, resides in the isolated tooth tissues, and is relatively independent of external factors. In addition, these studies indicate that the chick chorio-allantoic membrane and the semisolid-liquid culture medium supply the majority of the factors required for development of these tissues.

Ameloblasts↗