Polybrominated diphenyl ethers and organochloride pesticides in the organic matter of air suspended particles in Mexico valley: A diagnostic to evaluate public policies.

The presence of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) was analysed in air particulate matter ≤ 2.5 µm (PM2.5) and ≤10 µm (PM10) collected in the Metropolitan Zone of Mexico Valley (MZMV), during 2013 and 2014, respectively. Spatial and seasonal distributions of PM and their organic content named solvent extracted organic matter (SEOM) were determined. PM mass concentration and SEOM/PM ratios were compared with previous studies in 2006 in Mexico City. PM2.5 concentration was like found in 2006, however, PM10 decreased ∼43%. The SEOM/PM10 ratio was kept constant, suggesting a decrease in SEOM as well as PM10 emitted from natural sources, probably as a result of changes in the land use due to urban growth. A decrease ∼50% SEOM/PM2.5 ratio was observed in the same period, linked to adequate strategies and public policies applied by the local and federal governments to control the organic matter emitted from anthropogenic sources. Seven out of sixteen OCPs and five out of six PBDEs were found. The most common POPs were endosulfan I, endosulfan II, endosulfan sulfate, BDE-47 and BDE-99, present on >90% of the sampling days. OCPs in PM2.5 and PBDEs in PM10 showed seasonal variability. Higher PBDEs concentration in both particle sizes were observed at east and southeast of the MZMV, where one of the biggest landfills and wastewater treatment plants are located. OCPs in PM10 were mainly emitted from agricultural areas located to the southwest, southeast and east of the MZMV. OCPs in PM2.5 showed a regional contribution from the north and introduced into the valley. OCP degradation products were dominant over native OCPs, indicating no fresh OCP use. POPs comparison with other cities was made. Agreements and commissions created by the Mexican government reduced OCPs emissions, however, more effort must be made to control PBDE emission sources.

Detection of infrared fluorescence of carbon dioxide in R Leonis with SOFIA/EXES.

We report on the detection of hot CO2 in the O-rich AGB star R Leo based on high spectral resolution observations in the range 12.8 - 14.3 µm carried out with the Echelon-cross-Echelle Spectrograph (EXES) mounted on the Stratospheric Observatory for Infrared Astronomy (SOFIA). We have found ≃ 240 CO2 emission lines in several vibrational bands. These detections were possible thanks to a favorable Doppler shift that allowed us to avoid contamination by telluric CO2 features. The highest excitation lines involve levels at an energy of ≃ 7000 K. The detected lines are narrow (average deconvolved width ≃ 2.5 km s-1) and weak (usually ≲ 10% the continuum). A ro-vibrational diagram shows that there are three different populations, warm, hot, and very hot, with rotational temperatures of ≃ 550, 1150, and 1600 K, respectively. From this diagram, we derive a lower limit for the column density of ≃ 2.2 × 1016 cm-2. Further calculations based on a model of the R Leo envelope suggest that the total column density can be as large as 7 × 1017 cm -2 and the abundance with respect to H2 - 2.5 × 10-5. The detected lines are probably formed due to de-excitation of CO2 molecules from high energy vibrational states, which are essentially populated by the strong R Leo continuum at 2.7 and 4.2 µm.

Dendritic Immunotherapy Improvement for an Optimal Control Murine Model.

Therapeutic protocols in immunotherapy are usually proposed following the intuition and experience of the therapist. In order to deduce such protocols mathematical modeling, optimal control and simulations are used instead of the therapist's experience. Clinical efficacy of dendritic cell (DC) vaccines to cancer treatment is still unclear, since dendritic cells face several obstacles in the host environment, such as immunosuppression and poor transference to the lymph nodes reducing the vaccine effect. In view of that, we have created a mathematical murine model to measure the effects of dendritic cell injections admitting such obstacles. In addition, the model considers a therapy given by bolus injections of small duration as opposed to a continual dose. Doses timing defines the therapeutic protocols, which in turn are improved to minimize the tumor mass by an optimal control algorithm. We intend to supplement therapist's experience and intuition in the protocol's implementation. Experimental results made on mice infected with melanoma with and without therapy agree with the model. It is shown that the dendritic cells' percentage that manages to reach the lymph nodes has a crucial impact on the therapy outcome. This suggests that efforts in finding better methods to deliver DC vaccines should be pursued.

Discovery of the youngest sex chromosomes reveals first case of convergent co-option of ancestral autosomes in turtles.

Most turtle species possess temperature-dependent sex determination (TSD), but genotypic sex determination (GSD) has evolved multiple times independently from the TSD ancestral condition. GSD in animals typically involves sex chromosomes, yet the sex chromosome system of only 9 out of 18 known GSD turtles has been characterized. Here, we combine comparative genome hybridization (CGH) and BAC clone fluorescent in situ hybridization (BAC FISH) to identify a macro-chromosome XX/XY system in the GSD wood turtle Glyptemys insculpta (GIN), the youngest known sex chromosomes in chelonians (8-20 My old). Comparative analyses show that GIN-X/Y is homologous to chromosome 4 of Chrysemys picta (CPI) painted turtles, chromosome 5 of Gallus gallus chicken, and thus to the X/Y sex chromosomes of Siebenrockiella crassicollis black marsh turtles. We tentatively assign the gene content of the mapped BACs from CPI chromosome 4 (CPI-4) to GIN-X/Y. Chromosomal rearrangements were detected in G. insculpta sex chromosome pair that co-localize with the male-specific region of GIN-Y and encompass a gene involved in sexual development (Wt1-a putative master gene in TSD turtles). Such inversions may have mediated the divergence of G. insculpta sex chromosome pair and facilitated GSD evolution in this turtle. Our results illuminate the structure, origin, and evolution of sex chromosomes in G. insculpta and reveal the first case of convergent co-option of an autosomal pair as sex chromosomes within chelonians.

An innovative ultrasound assisted extraction micro-scale cell combined with gas chromatography/mass spectrometry in negative chemical ionization to determine persistent organic pollutants in air particulate matter.

New clean technologies are needed to determine concentration of organic pollutants without generating more pollution. A method to extract Persistent Organic Pollutants (POPs) from airborne particulate matter was developed using a novel technology recently patented called ultrasound assisted extraction micro-scale cell (UAE-MSC). This technology extracts, filters, collects the sample, and evaporates the solvent, on-line. No sample transfer is needed. The cell minimizes sample manipulation, solvent consumption, waste generation, time, and energy; fulfilling most of the analytical green chemistry protocol. The methodology was optimized applying a centred 23 factorial experimental design. Optimum conditions were used to validate and determine concentration of 16 organochlorine pesticides (OCls) and 6 polybrominated diphenyl ethers (PBDEs). The best conditions achieved were 2 extractions with 5mL (each) of dichloromethane over 5min (each) at 60°C and 80% ultrasound potency. POPs were determined by gas chromatography/mass spectrometry in negative chemical ionization (GC/MS-NCI). Analytical method validation was carried out on airborne particles spiked with POPs at seven concentration levels between 0.5 and 26.9pgm-3. This procedure was done by triplicate (N=21). Recovery, ranged between 65.5±2.3% and 107.5±3.0% for OCls and between 79.1±6.5% and 105.2±3.8% for PBDEs. Linearity (r2) was ≥0.94 for all compounds. Method detection limits, ranged from 0.5 to 2.7pgm-3, while limits of quantification (LOQ), ranged from 1.7 to 9.0pgm-3. A Bias from -18.6% to 9% for PBDEs was observed in the Standard Reference Material (SRM) 2787. SRM 2787 did not contain OCls. OCls recoveries were equivalent by UAE-MSC and Soxhlet methods UAE-MSC optimized extraction conditions reduced 30 times less solvent and decreased the extraction time from several hours to ten minutes, respect to Soxhlet. UAE-MSC was applied to 15 samples of particles less than 2.5µm (PM2.5) from three seasons (warm dry, rainy, and cold dry) collected in five sites around Mexico City. OCls (4,4'-DDE and endrin aldehyde) concentrations ranged from

Enhancing dendritic cell immunotherapy for melanoma using a simple mathematical model.

BACKGROUND: The immunotherapy using dendritic cells (DCs) against different varieties of cancer is an approach that has been previously explored which induces a specific immune response. This work presents a mathematical model of DCs immunotherapy for melanoma in mice based on work by Experimental Immunotherapy Laboratory of the Medicine Faculty in the Universidad Autonoma de Mexico (UNAM). METHOD: The model is a five delay differential equation (DDEs) which represents a simplified view of the immunotherapy mechanisms. The mathematical model takes into account the interactions between tumor cells, dendritic cells, naive cytotoxic T lymphocytes cells (inactivated cytotoxic cells), effector cells (cytotoxic T activated cytotoxic cells) and transforming growth factor ß cytokine (T G F-ß). The model is validated comparing the computer simulation results with biological trial results of the immunotherapy developed by the research group of UNAM. RESULTS: The results of the growth of tumor cells obtained by the control immunotherapy simulation show a similar amount of tumor cell population than the biological data of the control immunotherapy. Moreover, comparing the increase of tumor cells obtained from the immunotherapy simulation and the biological data of the immunotherapy applied by the UNAM researchers obtained errors of approximately 10 %. This allowed us to use the model as a framework to test hypothetical treatments. The numerical simulations suggest that by using more doses of DCs and changing the infusion time, the tumor growth decays compared with the current immunotherapy. In addition, a local sensitivity analysis is performed; the results show that the delay in time " τ", the maximal growth rate of tumor "r" and the maximal efficiency of tumor cytotoxic cells rate "aT" are the most sensitive model parameters. CONCLUSION: By using this mathematical model it is possible to simulate the growth of the tumor cells with or without immunotherapy using the infusion protocol of the UNAM researchers, to obtain a good approximation of the biological trials data. It is worth mentioning that by manipulating the different parameters of the model the effectiveness of the immunotherapy may increase. This last suggests that different protocols could be implemented by the Immunotherapy Laboratory of UNAM in order to improve their results.

Effects of breeder feeding restriction programs and incubation temperatures on progeny footpad development.

Footpad dermatitis begins early in life, and there is evidence of individual susceptibility. An experiment was conducted to evaluate the carryover effects of breeder feed restriction programs and incubation temperatures (TEM) on progeny footpad development at hatch, and 7 and 22 d. Cobb 500 fast feathering breeders were subjected to 2 dietary feed restriction programs during rearing: skip-a-day (SAD) and every-day feeding (EDF). At 60 wk of age, eggs from each group were collected and incubated according to 2 TEM, standard (S) eggshell temperature (38.1°C) and early-low late-high (LH). This second profile had low (36.9°C) eggshell temperature for the first 3 d, and standard temperature until the last 3 d when eggs were subjected to elevated (38.9°C) eggshell temperature. At hatch, 15 chicks from each treatment combination were sampled to obtain footpads for histological analysis. Seventy-two chicks per treatment were placed in 48 cages (6/cage), and raised to 22 d. At 7 and 22 d, 1 and 2 chickens, respectively, were sampled for footpads. The BW and group feed intake were recorded to obtain BW gain and feed conversion ratio at 7 and 21 d. Histological analysis assessed thickness and total area of stratus corneum (SC), epidermis, and dermis, and total papillae height. Data were analyzed as randomized complete block design in a 2 × 2 factorial arrangement of treatments. There was a negative effect of LH TEM on performance at both ages. An interaction effect on SC area and papillae height was observed at hatch. Additionally, SAD treatment increased thickness and area of footpad dermis. At 7 d, the SC parameters of the SAD progeny were increased. Epidermis thickness was affected by treatment interaction. Furthermore, LH TEM decreased epidermis thickness and dermis area. At 22 d, interaction effects were observed in thickness and area of SC and epidermis. Incubation S TEM increased thickness and area of dermis. It was concluded that breeder feed restriction programs and incubation TEM profiles may have carryover effects on histomorphological traits of footpads.

Herschel detects a massive dust reservoir in supernova 1987A.

We report far-infrared and submillimeter observations of supernova 1987A, the star whose explosion was observed on 23 February 1987 in the Large Magellanic Cloud, a galaxy located 160,000 light years away. The observations reveal the presence of a population of cold dust grains radiating with a temperature of about 17 to 23 kelvin at a rate of about 220 times the luminosity of the Sun. The intensity and spectral energy distribution of the emission suggest a dust mass of about 0.4 to 0.7 times the mass of the Sun. The radiation must originate from the supernova ejecta and requires the efficient precipitation of all refractory material into dust. Our observations imply that supernovae can produce the large dust masses detected in young galaxies at very high redshifts.

Theoretical studies on iron surface coating: adsorption of furan derivatives over Fe(n) clusters (n = 1-4).

In the transition from small molecules to solids, atomic clusters are studied widely not only because they can own unique properties due to the nanosized effect but also because they represent an intermediate stage. A systematic study on the structures and properties of clusters as a function of size could give information on the transition from clusters to bulk and determine at what size a cluster can mimic the bulk solid at least to some extent. The adsorption capability of furan derivatives 2-furfurylamine, 2-furfuryl alcohol and 2-furfuryl mercaptan with different iron-clusters was studied by DFT. The results show that since the compounds possess suitable structural and electronic parameters for the metal adhesion, it is observed that the functional group (NH2, OH and SH) of furan derivatives strongly adsorb over the metal clusters. Moreover, the calculated binding energy supports the existence of a bond between furan derivatives and metal, indicating the transfer of high charge density which in the delocalization region of furan ring to the metal (L(sigma) --> Fe). In the molecular orbital studies by detecting the overlap of HOMO (furan ring and functional group) with LUMO (iron), the binding nature of the compounds is then confirmed.

Protection in specific pathogen free chickens with live avian metapneumovirus and Newcastle disease virus vaccines applied singly or in combination.

This paper describes two experiments. In each experiment, 1-day-old specific pathogen free chicks were divided into three groups. In Experiment 1 - [avian metapneumo virus (aMPV) challenge] - one group served as unvaccinated controls; the second group was vaccinated with live aMPV (subtype B) vaccine only, and the third group received the aMPV vaccine in combination with live Newcastle disease virus (NDV) vaccine (VG/GA strain). Oropharyngeal swabs, tissues and blood samples were collected before and after challenge with a virulent subtype aMPV at 21 days post vaccination. Chicks were monitored for post-challenge clinical signs. Swabs and tissues were examined for the detection of challenge aMPV by virus isolation and by reverse-transcriptase polymerase-chain reaction. Sera were assayed for antibodies against aMPV and NDV. The single and combined vaccinated chicks were all protected against clinical signs and no challenge virus was isolated from either of the vaccinated-challenged groups. In Experiment 2 (NDV challenge), as in Experiment 1, chicks were divided into three groups where one group remained as unvaccinated control and the other two groups were vaccinated as above, except that the second group received live NDV vaccine only, instead of aMPV. At 21 days post vaccination, 15 chicks from each of the three groups were removed to a different site and challenged with a virulent NDV (Texas GB strain). Re-isolation of the challenge virus was not attempted. All chicks in both NDV-vaccinated challenged groups were protected against clinical signs and mortality. These results show that, based on parameters monitored for the respective challenge virus, simultaneous application of live aMPV and NDV vaccines did not affect the efficacy of either vaccine.

Interaction between a live avian pneumovirus vaccine and two different Newcastle disease virus vaccines in broiler chickens with maternal antibodies to Newcastle disease virus.

Broiler chicks with maternal antibodies to Newcastle disease virus (NDV) but none to avian metapneumovirus (APV) were divided into six groups. One group was kept as an unvaccinated control group. Three of the other groups were vaccinated at 1 day old with live APV vaccine or one of two live NDV vaccines (VG/GA or HB1). The remaining two groups received the APV vaccine in combination with either of the two NDV vaccines at 1 day old. At intervals after vaccination for up to 42 days, distribution of the viruses in the tissues was monitored, together with humoral antibody responses. Few NDV isolations were made from any NDV-vaccinated chicks, probably due to the presence of NDV maternal antibodies. In both dual-vaccinated groups, APV persisted longer (up to 21 days post vaccination (d.p.v.)) than in the single vaccinates (up to 14 d.p.v.). After 14 d.p.v., antibody titres against APV in both dual-vaccinated groups remained higher than the single APV vaccinates. For NDV haemagglutination inhibition antibodies, similar titres were found in the single and dual NDV VG/GA vaccinates. However, for chickens dually vaccinated with NDV HB1 and APV, the haemagglutination inhibition titres were significantly higher at 21 and 28 d.p.v. than the single HB1 vaccinates. These differences reflect the fact that NDV haemagglutination inhibition titres may depend on the NDV vaccine used.

Effects of homeopathic medications Eupatorium perfoliatum and Arsenicum album on parasitemia of Plasmodium berghei-infected mice.

Malaria is one of the most important parasitic diseases in the world and a major public health problem because of emerging drug-resistant strains of Plasmodium. A number of synthetic and natural compounds are now being analysed to develop more effective antimalarial drugs. We investigated the effect of homeopathic preparations of Eupatorium perfoliatum and Arsenicum album on parasitemia using a rodent malaria model. We found significant inhibitory effect on parasite multiplication with both medications with a level of 60% for Eupatorium perfoliatum at a 30 CH potency. Arsenicum album 0/6 gave 70% inhibition but this was less stable than Eupatorium perfoliatum. The number of schizonts was higher in animals treated with homeopathic medications. Although the mechanism of action is unknown, these agents would be good candidates as alternative or complementary medications in the treatment of malaria.

Interaction between live avian pneumovirus and Newcastle disease virus vaccines in specific pathogen free chickens.

One-day-old specific pathogen free White Leghorn chicks were vaccinated with live avian pneumovirus (APV) vaccine, live Newcastle disease virus (NDV) vaccine or both. At intervals up to 28 days after vaccination, distribution of the virus in the tissues was studied, together with humoral and mucosal antibody responses in lachrymal fluid and tracheal washes. APV vaccine was detected for almost twice as long in the dual vaccinates as in the single vaccinates. Higher numbers of isolations of ND virus vaccine were obtained from the dual rather than the single vaccinates at 7 days post-vaccination but the reverse occurred at 14 days. APV serum antibodies were significantly lower in the dual rather than the single vaccinates. However, there were similar levels of local APV-specific IgA in the lachrymal fluids of both single and dual APV vaccinates. NDV serum antibody titres in the dual vaccinates were significantly higher than in the singly NDV-vaccinated chickens. It appears that simultaneous vaccination of chicks with live APV and NDV vaccines causes temporary suppression of APV vaccine proliferation and reduces humoral antibody responses to it, although the antibody response to NDV is enhanced.

Protective efficacy of intermediate and intermediate plus infectious bursal disease virus (IBDV) vaccines against very virulent IBDV in commercial broilers.

The evolution of very virulent (vv) infectious bursal disease virus (IBDV) has led to significant economic losses in many poultry-producing areas. Despite vigorous vaccination strategies, IBDV has been difficult to control. The protective efficacy of IBDV vaccines is traditionally evaluated in specific pathogen-free (SPF) chickens. But under field conditions, residual maternal antibody (mAb) levels may interfere with vaccine efficacy. In this study, commercial broilers with various levels of maternally derived antibodies were vaccinated with IBDV vaccines of different virulence (vaccines 1-3, intermediate; vaccine 4, intermediate plus). At an average maternal virus-neutralizing antibody (mAb) level of log2 10.8 (range 7.6-11.6) at day of vaccination, only the intermediate plus vaccine induced IBDV antibodies after 18 days, while the other intermediate vaccines did not. At average mAb levels of log2 6.7 (range 5.6-8.6) at day of vaccination, all vaccines induced circulating antibodies, although the onset of antibody production differed significantly between strains (P < 0.05). While the intermediate plus vaccine induced enzyme-linked immunosorbent assay antibody levels already at 14 days postvaccination (PV), the intermediate vaccines induced significant antibody levels 28 (vaccines 1, 2) and 35 (vaccine 3) days PV. The time of IBDV antibody induction correlated with the onset of bursa lesions. The severity of lesions was comparable between vaccines 1, 3, and 4 (lesion score 4), while vaccine 2 induce only mild lesions of score 1 in 23% of the tested birds. Despite the induction of antibodies, none of the tested vaccines fully protected against challenge with vvIBDV. All challenged birds had either significantly higher bursal lesion scores or a higher IBDV antigen load in the bursa or sometimes both in comparison with nonchallenged birds (P < 0.05). Our study demonstrates that the evaluation of IBDV-vaccine efficacy is difficult in commercial broilers. For the first time, it was shown that the onset of bursa lesions and recovery of IBDV-vaccinated broilers is delayed in the presence of mAb in comparison with SPF chickens but not suppressed as previously assumed. At the time of challenge, vaccinated birds may still have significant bursa lesions and may lack target cells for IBDV-challenge virus. To be able to evaluate vaccine efficacy in commercial broilers, parameters such as intrabursal IBDV-antigen load should also be considered in conjunction with bursa lesion scores.

[Cellular mechanisms regulating neuronal excitability: functional implications and in epilepsy]. / Mecanismos celulares reguladores de la excitabilidad celular: implicaciones funcionales y en epilepsia.

INTRODUCTION AND METHOD: The cellular mechanisms that regulate neuronal excitability and the propagation of electrical signals in the dendrites of pyramidal neurons are incompletely understood and of key functional and pathological importance. The capacity of dendrites to actively propagate action potentials is vital in processes related to memory and learning. The deregulation of dendritic excitability may also contribute to epilepsy. The contributions of ionic conductances that regulate neuronal excitability and dendritic signal propagation have been analyzed using the in vitro hippocampal slice technique and recordings of transmembrane voltage and current of CA1 pyramidal neurons. One of these ionic currents is the slow calcium activated potassium current that generates the slow spike after hyperpolarization. CONCLUSION: The dendritic localization of this current and its role in the control and propagation of electrical signals provide a key subcellular mechanisms for the control of the dendro somatic spread of synaptic signals and spike backpropagation, cellular processes closely linked with learning, memory and epilepsy.

Glutathione-related enzymes in cell cultures from different regions of human epididymis.

Protection of maturing sperm from potential endogenous or exogenous harmful substances during their transit throughout the epididymis is a critical event. The authors studied the activity of gamma-glutamyl transpeptidase (GGT) and glutathione S-transferase (GST), and glutathione (GSH) levels in epithelial cell cultures from human caput, corpus, and cauda epididymides. Tissue was obtained from patients undergoing therapeutic orchidectomy for prostatic cancer. Enzymatic activity was measured in conditioned media and cellular fractions. Androgen influence was also evaluated. Both enzymatic activities were found in cellular homogenates and conditioned media from cultures of all epididymal regions. GGT activity was highest in cultures from cauda epididymis, both in conditioned media and cell fractions, while GST activity did not show regional differences in conditioned media, but exhibited higher activity in cell homogenates from cauda cultures than those obtained from corpus and caput epididymis. GSH level showed no regional difference in cell homogenates and it could not be detected in conditioned media by the method used. Presence of different concentrations of dihydrotestosterone (DHT) had no influence neither on the enzymatic activities nor GSH concentration. The results indicate that GGT and GST are present along the human epididymis and a fraction or isoform of these enzymes might be secreted to the luminal fluid to play a detoxificative role in sperm maturation.

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.

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.

[Induction of polyvalent immunity against Actinobacillus pleuropneumoniae in an experimental rat model]. / Inducción de inmunidad polivalente contra Actinobacillus pleuropneumoniae en un modelo experimental en la rata.

Using an experimental model of passive immunity in the rat, the immunizing effect of live cells of Actinobacillus pleuropneumoniae serotypes 1, 3, 5, 7, 9 and 12 was tested against a challenge with serotype 1. It was observed that serotypes 5, 7 and 9 induced polyvalent immunity. Additionally, agglutinating antibodies to the homologous and heterologous serotype were titrated in the sera of immunized mothers; the results indicated that groups immunized with serotypes 5, 7 and 9 had higher titers against serotype 1.

Erythropoietic action of dexamethasone on the anemia associated with an experimental chronic renal failure.

Partially nephrectomized anemic uremic rats were injected with dexamethasone phosphate (10, 50 and 500 micrograms/kg/day), i.p., and erythropoietin (5 U/day), s.c., for 10 days. A marked and usually significant stimulatory effect on erythropoiesis was seen in all uremic animals treated. Administration of erythropoietin and dexamethasone produced a pronounced increment in hemoglobin, hematocrit and circulating reticulocytes. The increase in red blood cell production was also evident through the generally increased absolute numbers of nucleated erythroid cell precursors per milligram of bone marrow. The highest increases were seen in the erythropoietin treated uremic rats. A dose effect correlation was apparent in uremic rats receiving 3 different doses of dexamethasone. Dexamethasone may stimulate erythropoiesis in our anemic uremic rats through a previous augmentation of erythropoietin production in the residual renal mass. A synergistic permissive effect of dexamethasone increasing the sensitivity of the erythropoietin-responsive cells to erythropoietin in bone marrow is also quite possible.