Facial nerve identification with fluorescent dye in rats

PURPOSE The parotidectomy technique still has an elevated paresis and paralysis index, lowering patient life's quality. The correct identification of the facial nerve can prevent nerve damage. Fluorescent dye identifies nerves in experimental studies but only few articles focused its use on facial nerve study in parotidectomies. We aimed to stain the rat facial nerve with fluorescent dye to facilitate visualization and dissection in order to prevent injuries. METHODS Forty adult male Wistar rats were submitted to facial injection of saline solution (Gsf-control group, 10) or fluorescent dye solution (Gdye group, 30) followed by parotidectomy preserving the facial nerve, measuring the time for localization and facility of localization (LocTime and LFN). Nerve function was assessed using the Vibrissae Movements (PMV) and Eyelid Closure Motion (PFP) scores. RESULTS Nerve localization was faster in Gdye group, with 83% Easy LFN rate. The Gdye group presented with low nerve injury degree and better PMV and PFP scores, with high sensitivity and accuracy. CONCLUSIONS This experimental method of facial nerve fluorescence was effective for intraoperative nerve visualization, identification and preservation. The technique may be used in future facial nerve studies, translated to humans, contributing to the optimization of parotid surgery in the near future.

Differentiation of human umblical cord mesenchymal stem cells into Leydig cells in the rat testis interstitium: An experimental study / 中华男科学杂志

<p><b>Objective</b>To explore the feasibility of inducing human umbilical cord mesenchymal stem cells (HUMSCs) to differentiate into Leydig cells in the interstitial tissue of the rat testis.</p><p><b>METHODS</b>HUMSCs were obtained by tissue blocks culture attachment and their purity and multi-lineage differentiation ability were verified by flow cytometry and chondrogenic/adipogenic/osteogenic differentiation. Then the HUMSCs were marked by CM-Dil and transplanted into the interstitial tissue of the rat testis. At 4 and 8 weeks after transplantation, the survival and differentiation status of the HUMSCs were observed by immunofluorescence staining and flow cytometry. The suspension of the rat Leydig cells was obtained at 8 weeks for determining the expression of the Leydig cell marker 3β-HSD in the HUMSCs, the cells labeled with CM-Dil were sorted and cultured, and the medium collected after 3 days of culture for measurement of the testosterone level.</p><p><b>RESULTS</b>The expression of the Leydig cell marker CYPllal was not observed in the HUMSCs at 4 weeks but found at 8 weeks after transplantation and the differentiation rate of 3β-HSD was about 14.5% at 8 weeks. CM-Dil labeled cells survived after sorting and testosterone was detected in the medium.</p><p><b>CONCLUSIONS</b>HUMSCs are likely to differentiate into Leydig cells in the interstitium of the rat testis.</p>

Therapeutic Options in Idiopathic Burning Mouth Syndrome: Literature Review

Introduction Burning mouth syndrome (BMS) is characterized by a burning sensation in the tongue, palate, lips, or gums of no well-defined etiology. The diagnosis and treatment for primary BMS are controversial. No specific laboratory tests or diagnostic criteria are well established, and the diagnosis is made by excluding all other possible disorders. Objective To review the literature on the main treatment options in idiopathic BMS and compare the best results of the main studies in 15 years. Data Synthesis We conducted a literature review on PubMed/MEDLINE, SciELO, and Cochrane-BIREME of work in the past 15 years, and only selected studies comparing different therapeutic options in idiopathic BMS, with preference for randomized and double-blind controlled studies. Final Comments Topical clonazepam showed good short-term results for the relief of pain, although this was not presented as a definitive cure. Similarly, α-lipoic acid showed good results, but there are few randomized controlled studies that showed the longterm results and complete remission of symptoms. On the other hand, cognitive therapy is reported as a good and lasting therapeutic option with the advantage of not having side effects, and it can be combined with pharmacologic therapy. .

Establishment and characterization of dual-color fluorescence nude mouse models of glioma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To establish red-green dual-color fluorescence glioma model in nude mice and to explore its practical values.</p><p><b>METHODS</b>CM-DiI-stained rat glioma C6 cells (C6-CM- DiI cells) expressing red fluorescence were inoculated into the brain of athymic nude mice expressing green fluorescence protein (NC-C57BL/6J-EGFP). Then the whole-body dual-color fluorescence imaging was detected dynamically. Finally whole brains of the tumor-bearing mice were removed and 5 µm thick serial frozen slices were made. Light microscopy, fluorescence microscopy and confocal laser scanning microscopy were performed to observe the transplanted tumor tissue structure and fluorescent cells.</p><p><b>RESULTS</b>Tumor mass with red fluorescence increased gradually under continuous in-vivo fluorescence imaging monitoring. Under the fluorescence microscope, cells with red, green and yellow fluorescence were observed in the frozen sections of transplanted tumor tissue and the mutual structural relationship among them could be defined. The tumor cells migration, implantation and cell fusion between transplanted tumor cells and host cells could be observed. It could be distinguished according to the fluorescence, that blood vessels of tumor-origin displayed red fluorescence, blood vessels of host-origin displayed green fluorescence and mosaic blood vessels appeared yellow fluorescence. It was depicted that host innate astrocytes and oligodendrocytes in the microenvironment at the tumor periphery could be activated and dedifferentiated into nestin-positive cells.</p><p><b>CONCLUSIONS</b>In contrast to traditional animal model, the dual-color fluorescence imaging of nude mouse models of glioma possesses enormous advantages in investigating tumor mass in-vivo fluorescence imaging, tumor cells migration and metastasis, tumor angiogenesis and reactive activation of host innate cells in the microenvironment at tumor periphery, thus, has highly practical application value.</p>

Distribution and accumulation of Cy5.5-labeled thermally cross-linked superparamagnetic iron oxide nanoparticles in the tissues of ICR mice

Free Cy5.5 dye and Cy5.5-labeled thermally cross-linked superparamagnetic iron oxide nanoparticles (TCL-SPION) have been routinely used for in vivo optical imaging. However, there is little information about the distribution and accumulation of free Cy5.5 dye and Cy5.5-labeled TCL-SPION in the tissues of mice. Free Cy5.5 dye (0.1 mg/kg body weight) and Cy5.5-labeled TCL-SPION (15 mg/kg body weight) were intravenously injected into the tail vein of ICR mice. The biodistribution and accumulation of the TCL-SPION and Cy5.5 were observed by ex vivo optical imaging and fluorescence signal generation at various time points over 28 days. Cy5.5 dye fluorescence in various organs was rapidly eliminated from 0.5 to 24 h post-injection. Fluorescence intensity of Cy5.5 dye in the liver, lung, kidney, and stomach was fairly strong at the early time points within 1 day post-injection. Cy5.5-labeled TCL-SPION had the highest fluorescence density in the lung at 0.5 h post-injection and decreased rapidly over time. Fluorescence density in liver and spleen was maintained over 28 days. These results suggest that TCL-SPION can be useful as a carrier of therapeutic reagents to treat diseases by persisting for long periods of time in the body.

Effect of quercetin on apoptosis of PANC-1 cells / 대한외과학회지

PURPOSE: To investigate the chemotherapeutic effect of quercetin against cancer cells, signaling pathway of apoptosis was explored in human pancreatic cells. METHODS: Various anticancer drugs including adriamycin, cisplatin, 5-fluorouracil (5-FU) and gemcitabine were used. Cell viability was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphe-nyltetra zolium bromide assay. Apoptosis was determined by 4'-6-diamidino-2-phenylindole nuclei staining and flow cytometry in PANC-1 cells treated with 50 microg/mL quercetin for 24 hours. Expression of endoplas mic reticulum (ER) stress mediators including, Grp78/Bip, p-PERK, PERK, ATF4, ATF6 and GADD153/CHOP proteins were measured by Western blot analysis. Mitochondrial membrane potential was measured by fluorescence staining with JC-1, rhodamine 123. Quercetin induced the apoptosis of PANC-1, which was characterized as nucleic acid and genomic DNA fragmentation, chromatin condensation, and sub-G0/G1 fraction of cell cycle increase. But not adriamycin, cisplatin, gemcitabine, and 5-FU. PANC-1 cells were markedly sensitive to quercetin. RESULTS: Treatment with quercetin resulted in the increased accumulation of intracellular Ca2+ ion. Treatment with quercetin also increased the expression of Grp78/Bip and GADD153/CHOP protein and induced mitochondrial dysfunction. Quercetin exerted cytotoxicity against human pancreatic cancer cells via ER stress-mediated apoptotic signaling including reactive oxygen species production and mitochondrial dysfunction. CONCLUSION: These data suggest that quercetin may be an important modulator of chemosensitivity of cancer cells against anticancer chemotherapeutic agents.

Establishment of a hydrogel chip for high-throughput detection of Y chromosome microdeletions / 中华男科学杂志

<p><b>OBJECTIVE</b>To establish a high-sensitivity, high-specificity and low-cost hydrogel chip platform for the clinical screening of Y chromosome microdeletions.</p><p><b>METHODS</b>Site-specific extended primers with a common sequence at the 5' end were used for hybridizing with the target. The Cy5-dUTP was incorporated into the products by primer extension, and the products were labeled with fluorescence. Then the extended products were added to the chip for hybridizing with acrylamide-modified common probes immobilized on the chip. After removal of the free Cy5-dUTP by electrophoresis, the signals were obtained by fluorescence scanning. And the detecting conditions of this method were optimized.</p><p><b>RESULTS</b>SY254 of 9 samples was successfully detected with the hydrogel chip. The results showed that 3 were normal and the other 6 with microdeletions (1 female sample as a negative control), which coincided with the results of conventional multiplex PCR-electrophoresis.</p><p><b>CONCLUSION</b>The hydrogel chip platform we established has provided a new technique for the detection of Y chromosome microdeletions, and is beneficial to the diagnosis and treatment of male infertility.</p>

Assessment of Collagen-Induced Arthritis Using Cyanine 5.5 Conjugated with Hydrophobically Modified Glycol Chitosan Nanoparticles: Correlation with 18F-Fluorodeoxyglucose Positron Emission Tomography Data

OBJECTIVE: To evaluate the potential and correlation between near-infrared fluorescence (NIRF) imaging using cyanine 5.5 conjugated with hydrophobically modified glycol chitosan nanoparticles (HGC-Cy5.5) and 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) imaging of collagen-induced arthritis (CIA). MATERIALS AND METHODS: We used 10 CIA and 3 normal mice. Nine days after the injecting collagen twice, microPET imaging was performed 40 minutes after the intravenous injection of 9.3 MBq 18F-FDG in 200 microL PBS. One day later, NIRF imaging was performed two hours after the intravenous injection of HGC-cy5.5 (5 mg/kg). We assessed the correlation between these two modalities in the knees and ankles of CIA mice. RESULTS: The mean standardized uptake values of 18F-FDG for knees and ankles were 1.68 +/- 0.76 and 0.79 +/- 0.71, respectively, for CIA mice; and 0.57 +/- 0.17 and 0.54 +/- 0.20 respectively for control mice. From the NIRF images, the total photon counts per 30 mm2 for knees and ankles were 2.32 +/- 1.54 x 10(5) and 2.75 +/- 1.51 x 10(5), respectively, for CIA mice, and 1.22 +/- 0.27 x 10(5) and 0.88 +/- 0.24 x 10(5), respectively, for control mice. These two modalities showed a moderate correlation for knees (r = 0.604, p = 0.005) and ankles (r = 0.464, p = 0.039). Moreover, both HGC-Cy5.5 (p = 0.002) and 18F-FDG-PET (p = 0.005) imaging also showed statistically significant differences between CIA and normal mice. CONCLUSION: NIRF imaging using HGC-Cy5.5 was moderately correlated with 18F-FDG-PET imaging in the CIA model. As such, HGC-Cy5.5 imaging can be used for the early detection of rheumatoid arthritis.

Near-infrared fluorescent zinc-dipicolylamine: a new molecular imaging probe to monitor the efficiency of chemotherapy / 中南大学学报(医学版)

OBJECTIVE@#To investigate the feasibility of a novel molecular probe of Zn-DPA-PSS794 to monitor the efficiency of doxorubicin to ovarian cancer and compare with Cy5.5-annexin V.@*METHODS@#Efficiency of doxorubicin to OVCAR-8 cells in vitro was measured by MTT assay and flow cytometry. The in vivo studies were performed on an OVCAR-8 xenograft tumor model. Mice were divided into a control group and a treatment group. Each group was divided into 2 subgroups, DPA and annexin V. In the treatment group, the mice were treated with doxorubicin for 2 doses. All mice were performed optical imaging by Zn-DPA-PSS794 or Cy5.5-annexin V, respectively and then sacrificed. The tumor was separated and stained by HE. The expression of caspase-3 protein was measured by Western blot.@*RESULTS@#The IC50 of doxorubicin to OVCAR-8 was 6 μmol/L. The percentage of apoptosis and dead cells was 35% after doxorubicin treatment. In the optical image, photons accumulated in the tumor either by Zn-DPA-PSS794 or Cy 5.5-annexin V in the treatment group. That was negative in the control group. The fluorescence intensity had significant difference between the 2 groups(P<0.001). The nuclei were big and stained with deep color after the cells were stained with HE. The caspase-3 expression was high in the treatment group, while it was low in the control group.@*CONCLUSION@#Zn-DPA-PSS794 as a probe used by optical imaging can monitor the efficiency of doxorubicin to OVCAR-8 xenograft tumor, which is similar to Cy5.5-annexin V.

Use of Peristeum as a Source of Endothelial-like Cells

Development of the research on the application of chlorotoxin in imaging diagnostics and targeted therapies for tumors / 癌症

Precisely locating tumors always proves to be difficult. To find a molecule that can specifically bind to tumor cells is the key. Recently, chlorotoxin (CTX) has been proved to be able to bind to many kinds of tumor cells. The CTX receptor on the cell surface has been demonstrated to be matrix metalloproteinase-2 (MMP-2). Many researchers have combined CTX with other molecules, including 131I, Cy5.5, iron oxide nanoparticles coated by polyethylene glycol (NP-PEG), and so on, and thus synthesized various types of probes that can be detected by gamma-camera, single photon emission computed tomography (SPECT) or magnetic resonance imaging (MRI). With these methods, the binding degree of CTX could be assessed. These studies demonstrated that CTX has a highly specific binding ability, high stability, and security. CTX could also inhibit or kill the tumor cells. A nonviral nanovector has been developed for gene therapy. As a result, it gradually develops into a new method of diagnosis and targeted therapy of tumors. This article reviews the current progress on CTX including the origin, chemical construction, the mechanism of binding with tumor cells, and the application to tumor imaging diagnosis and therapy.

Interactions of bacterial polysaccharides with cationic dyes: Physicochemical studies.

Capsular polysaccharides (SPS) are an integral component of gram-negative bacteria, and also have potential use as vaccine. In this paper, interactions of SPS isolated from Klebsiella strains K20 and K51 with cationic dyes pinacyanol chloride (PCYN) and acridine orange (AO) were studied by absorbance and fluorescence measurements. Both the polysaccharides having glucuronic acid as the potential anionic site induced strong metachromasy (blue shift ~100 nm) in the PCYN. The spectral changes were studied at different polymer/dye molar ratios (P/D = 0-40). A complete reversal of metachromasy was observed upon addition of co-solvents, suggesting the breakaway of dye molecules from the biopolymer matrix. Binding constant, changes in free energy, enthalpy and entropy of the dye polymer complex were also computed from the spectral data at different temperatures to reveal the nature of the interaction. Quenching of fluorescence of AO by the polymers and the incorporated mechanisms were also explored.

Comparison of the effect of Angelica polysaccharide, platelet-derived growth factor and thrombopoietin on megakaryocytopoiesis / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the effect of Angelica polysaccharide (APS), platelet-derived growth factor (PDGF) and thrombopoietin (TPO) on the proliferation and apoptosis of human megakaryocytic cell line M-07e.</p><p><b>METHODS</b>Cell count and the viability testing of M-07e cells (trypan blue exclusion assay) were performed at 24 hours, 48 hours and 72 hours after treatment with APS, PDGF or TPO. Three apoptosis related flow cytometric assays including Annexin V, Caspase-3 and JC-1 were performed to determine apoptotic rate of each group at 72 hours after the treatment.</p><p><b>RESULTS</b>After the incubation, the number of M-07e cells in the APS, PDGF and TPO group increased and the viabilities of the three groups were significantly higher than the control group (P < 0.05). The dead cells in the APS, PDGF and TPO group were (19.41 +/- 7.59)%, (21.38 +/- 7.25)% and (18.77 +/- 8.00)%, respectively by flow cytometry using Annexin V method, which were significantly lower compared to the control group (34.33 +/- 5.46)%. The expression of the activated caspase-3 in the group of APS, PDGF and TPO were (12.27 +/- 5.18)%, (12.39 +/- 6.26)% and (13.75 +/- 8.25)%, the APS and PDGF group decreased significantly compared to the control group (18.92 +/- 6.09)%. The ratio of total cell deaths in the APS, PDGF and TPO group were (23.64 +/- 6.69)%, (28.00 +/- 10.05)% and (27.99 +/- 8.99)%, the ratio in APS group decreased significantly compared to the control group (39.48 +/- 11.86)% by JC-1 method. Differences between APS and PDGF groups and between APS and TPO groups were not statistically significant.</p><p><b>CONCLUSION</b>APS, PDGF and TPO have similar effect in stimulating proliferation and inhibiting serum-free-culture induced apoptosis of M-07e cells.</p>

Apoptosis induced by DNA primase inhibitor 3,3'-diethyl-9-methylthia-carbocyanine iodide in human leukemia HL-60 cells / 药学学报

<p><b>AIM</b>To investigate apoptosis induced by 3,3'-diethyl-9-methylthia-carbocyanine iodide (DMTCCI), an inhibitor of DNA primase found in our previous study, and the mechanism of DMTCCI in human myelogenous leukemia HL-60 cells.</p><p><b>METHODS</b>HL-60 cells were cultured in RPMI-1640 medium and treated with different concentrations of DMTCCI. MTT assay was used to detect growth inhibition. Flow cytometry and DNA ladders were used to detect apoptosis. Western blotting was used to observe the expression of survivin, Bcl-xL, Bad, Bax, Bcl-2, caspase-9, caspase-3, caspase-6, PARP, DFF45 and lamin B protein. Caspase-3 activity was measured by ApoAlert Caspase-3 Assay Kit.</p><p><b>RESULTS</b>DMTCCI inhibited proliferation of human leukemia HL-60 cells with IC50 value of 0.24 micromol x L(-1). The results of flow cytometry and DNA ladders showed that DMTCCI could induce apoptosis of HL-60 cells. The expression levels of protein survivin and Bcl-xL were down-regulated, Bad and Bax were up-regulated, while Bcl-2 protein had no change in response to DMTCCI treatment in HL-60 cells. Treatment of HL-60 cells with DMTCCI induced the proteolytic cleavage of caspase-9, caspase-3, caspase-6, PARP, DFF45 and lamin B protein. Caspase-3 activity apparently increased at 3 h and reached a peak at 12 h after exposure to 1 micromol x L(-1) of DMTCCI in HL-60 cells.</p><p><b>CONCLUSION</b>DMTCCI inhibited proliferation and induced apoptosis of human leukemia HL-60 cells. Bcl-2 family proteins, survivin and caspases family proteins might play a role in the apoptosis process induced by DMTCCI.</p>

Development of a new high-throughput screening model for human high density lipoprotein receptor (CLA-1) agonists / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To develop a new high-throughput screening model for human high-density lipoprotein (HDL) receptor (CD36 and LIMPII analogous-1, CLA-1) agonists using CLA-1-expressing insect cells.</p><p><b>METHODS</b>With the total RNA of human hepatoma cells BEL-7402 as template, the complementary DNA (cDNA) of CLA-1 was amplified by reverse transcription-polymerase chain reaction (RT-PCR). Bac-to-Bac baculovirus expression system was used to express CLA-1 in insect cells. CLA-1 cDNA was cloned downstream of polyhedrin promoter of Autographa californica nuclear polyhedrosis virus (AcNPV) into donor vector pFastBac1 and recombinant pFastBac1-CLA-1 was transformed into E. coli DH10Bac to transpose CLA-1 cDNA to bacmid DNA. Recombinant bacmid-CLA-1 was transfected into Spodoptera frugiperda Sf9 insect cells to produce recombinant baculovirus particles. Recombinant CLA-1 was expressed on the membrane of Sf9 cells infected with the recombinant baculoviruses. A series of parameters of DiI-lipoprotein binding assays of CLA-1-expressing Sf9 cells in 96-well plates were optimized.</p><p><b>RESULTS</b>Western blot analysis and DiI-lipoprotein binding assays confirmed that CLA-1 expressed in insect cells had similar immunoreactivity and ligand binding activity as its native counterpart. A reliable and sensitive in vitro cell-based assay was established to assess the activity of CLA-1 and used to screen agonists from different sample libraries.</p><p><b>CONCLUSION</b>Human HDL receptor CLA-1 was successfully expressed in Sf9 insect cells and a novel high-throughput screening model for CLA-1 agonists was developed. Utilization of this model allows us to identify potent and selective CLA-1 agonists which might possibly be used as therapeutics for atherosclerosis.</p>

Detection of differentially expressed genes in human autosomal dominant polycystic kidney tissue / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect the differentially expressed genes in human polycystic kidney by cDNA microarray.</p><p><b>METHODS</b>The PCR products of 8398 genes were spotted onto a chip in array. Both mRNAs isolated from polycystic kidney tissue and normal kidney tissue were reversely transcribed to cDNAs with the incorporation of fluorescent dUTP (Cy5-dUTP and Cy3-dUTP) for preparing the hybridization probes. The mixed probes were hybridized to the cDNA microarray. Then the cDNA microarray was scanned for the fluorescent signals and the display of differences between the 2 tissues. IGF1 mRNA, one of the up regulated genes was detected by in situ hybridization technique in the two tissues to validate the result from cDNA microarray.</p><p><b>RESULTS</b>The result indicated that the expressions of 263 genes were up regulated while the expressions of 94 genes were down regulated in the polycystic kidney tissue among the 8398 target genes. Bioinformatical analysis of those genes had been performed. The up-regulated genes were mainly the ones of oncogene, cellular skeleton and movement, apoptosis related protein, cell signal transduction protein, and cytokine. The down regulated genes were mainly the ones of anti-oncogene, DNA binding and transcription factors, cell signal transduction protein, and metabolism protein. The IGF1 mRNA expression detected by in situ hybridization was consequently consistent with the cDNA microarray.</p><p><b>CONCLUSION</b>cDNA microarray is an effective and quick method for studying differential expressed genes. Three hundred and fifty-seven differentially expressed genes with different functions were revealed in the polycystic kidney tissue, which may play some roles in the progression of polycystic kidney.</p>

Effect of local background intensities in the normalization of cDNA microarray data with a skewed expression profiles

Normalization of the data of cDNA microarray is an obligatory step during microarray experiments due to the relatively frequent non-specific errors. Generally, normalization of microarray data is based on the null hypothesis and variance model. In the Yang's model (Yang et al., 2001), at least two types of noises are included. The one is additive noise and the other is multiplicative noise. Usually, background is considered as one of additive noise to the signal and the variation between the signal pixels is the representative multiplicative noise. In this study, the relation between the signal (spot intensity minus background intensity) and background was observed and the influence of background on normalization as a representative additive factor was investigated. Although the relation has not been considered as a factor affecting the normalization, it could improve the accuracy of microarray data when the normalization was carried out considering signal/background ratio. The background dependent normalization decreased the number of genes whose expression levels were changed significantly and it could make their distribution more consistent through the whole range of signal intensities. In this study, printing pin dependent normalization was also carried out regarding the printing pin as a representative multiplicative noise. It improved the distribution of spots in the Cy3-Cy5 scatter plot, but its effect was slight. These studies suggest that there are some influences of the signals on the local backgrounds and they must be considered for the normalization of cDNA microarray data.

Spectrophotometric and spectrofluorometric studies on interaction of cationic dyes with bacterial capsular polysaccharide.

Interaction of Klebsiella K14 capsular polysaccharide with cationic dyes pinacyanol chloride, acridine orange and phenosafranin has been studied by spectrophotometric and spectrofluorometric techniques. The polymer containing both glucuronic acid and pyruvic acid in its repeating unit behaved as a unique polyelectrolyte. It induced blue shift of the absorption band of pinacyanol chloride indicating strong metachromasy. Stoichiometry of the polyanion and the dye cations in the polymer-dye compound (1:2) indicated that both glucuronic acid and pyruvic acid acted as potential anionic sites for interaction with the cationic dye molecules. The stoichiometry of anionic site (of polyanion): cationic site (of dye) in the polymer dye compound was calculated as 1:1. Interaction of the polymer with acridine orange and phenosafranin dyes studied by fluorescence measurements demonstrated Stern-Volmer type of quenching. Equivalent weight of the polymer was determined by spectrophotometric and spectrofluorometric titrations. From the present studies chromotropic property of the polymer was established.

Poda selectiva de las proyecciones comisurales del colículo superior de la rata durante el desarrollo posnatal / Selective pruning of commisural projections in the superior colliculus of the rat during posnatal development

En el presente trabajo he estudiado los cambios que ocurren en proyecciones intercoliculares rata durante el desarrollo posnatal de la rata. El uso de la carbocianina DiI ha permitido marcar los axones comisurales del colículo superior. Durante el período postnatal temprano (P-1 a P-5), se observan proyecciones comisurales muy abundantes, que se distribuyen a gran parte del colículo superior contralateral. A partir del día 15 estas proyecciones se van reduciendo para adquirir, alrededor del día 30, el aspecto observado en el adulto. Existe, por lo tanto, un proceso de poda o eliminación selectiva de las proyecciones intercoliculares durante el desarrollo postnatal