Evaluating the glycophenotype on breast cancer tissues with quantum dots-Cramoll lectin conjugates.

During carcinogenesis, changes in the glycosylation can modulate many biological processes. Thus, the interest in exploring and understanding the roles of carbohydrates as cancer biomarkers has been increasing. Lectins have been applied as useful tools in glycobiology, especially when associated with fluorescent reporters. Therefore, to take advantage of the physicochemical properties of quantum dots (QDs), herein, we conjugated Cramoll, a lectin that recognizes glucose/mannose residues, with those nanoparticles. We applied the conjugates to investigate the glycocode of normal, fibroadenoma (FB), and invasive ductal carcinoma (IDC) human breast tissues. Additionally, we proposed a method to quantitatively evaluate the tissue labeling intensity by a fluorescence microplate assay (FMA). Conjugates showed intense fluorescence and specificity. The lectin activity and secondary structure were also preserved after the conjugation with QDs. Moreover, fluorescence images showed that ductal cells of normal and FB tissues were preferentially labeled by conjugates, whereas both cells and stroma were strongly labeled in IDC. FMA showed in a quantitative, practical, and sensitive way that the level of exposed glucose/mannose residues increased accordingly to the sample malignancy degree. In conclusion, QDs-Cramoll conjugates can be considered effective, specific, and versatile probes to evaluate glycan profiles in normal and transformed tissues, by fluorescence microscopy as well as FMA quantification. Furthermore, FMA showed to be a potential method that can be applied with other fluorescent conjugates.

Magnetic Parkia pendula seed gum as matrix for Concanavalin A lectin immobilization and its application in affinity purification.

The present work aimed to magnetize Parkia pendula seeds gum and use it as a matrix for Concanavalin A covalent immobilization. This composite was applied in affinity purification of glycoconjugates. Parkia pendula seeds were hydrated and the gum provenient from the supernatant was precipitated and washed with ethanol and dried. The gum was magnetized in co-precipitation using solutions of Fe+2 and Fe+3. Matrix activation was accomplished with NaIO4. Magnetized Parkia pendula seeds gum with covalently immobilized Concanavalin A was used as an affinity matrix for the recognition of bovine serum fetuin glycoprotein. Fetuin elution was carried out with a solution of glucose (300mM) and evaluated through SDS-PAGE. The efficiency of lectin immobilization and fetuin purification were 63% and 14%, respectively. These results indicate that the composite produced is a promising magnetic polysaccharide matrix for lectins immobilization. Thus, such system can be applied for affinity purification allowing an easy recovery by magnetic field.

Lectin staining patterns in human gastric mucosae with and without exposure to Helicobacter pylori / Padrões de ligação de lectinas em mucosa gástrica humana com e sem exposição a Helicobacter pylori

The aim of the present study was to evaluate qualitative changes in the glycoconjugate expression in human gastric tissue of positive and negative patients for Helicobacter pylori, through lectins: Wheat Germ Agglutinin (WGA) and Concanavalin A (Con A). The lectins recognized differently the glycoconjugates in the superficial mucous layer at the gastric tissues. The results suggest a significant change in the carbohydrate moieties present on the surface of the gastric cells during infection.

O objetivo do presente estudo foi avaliar as mudanças qualitativas na expressão de glicoconjugados em tecidos gástrico humano de pacientes infectados ou não pelo Helicobacter pylori, através das lectinas: Wheat germ agglutinin (WGA) e Concanavalina A (Con A). As lectinas reconheceram diferentemente os glicoconjugados nas camadas mucosas superficiais do tecido gástrico. Os resultados sugerem mudanças significantes nas porções de carboidratos presentes nas células gástricas durante a infecção.

Treatment of human acute schistosomiasis with oxamniquine induces an increase in interferon-gamma response to Schistosoma mansoni antigens.

Patients with acute schistosomiasis were studied before and after oxamniquine treatment. They had been exposed to cercariae 5 to 9 weeks before, and presented compatible clinical manifestations, eosinophilia, and high levels of total IgE. Interferon-gamma (IFN-gamma) and interleukin-4 were measured by ELISA in whole blood samples under soluble egg antigen or soluble adult worm preparation stimulation. After treatment, the reduction of leukocytosis and eosinophilia were not significant, but total IgE levels decreased significantly, in contrast to IFN-gamma levels that were significantly increased. The oxamniquine treatment of acute schistosomiasis patients is followed by an improvement of a Th1 response in vitro. If this response has a protective aspect is unknown, and some investigations need to be realized.

Treatment of human acute schistosomiasis with oxamniquine induces an increase in interferon-gamma response to Schistosoma mansoni antigens

Patients with acute schistosomiasis were studied before and after oxamniquine treatment. They had been exposed to cercariae 5 to 9 weeks before, and presented compatible clinical manifestations, eosinophilia, and high levels of total IgE. Interferon-gamma (IFN-gamma) and interleukin-4 were measured by ELISA in whole blood samples under soluble egg antigen or soluble adult worm preparation stimulation. After treatment, the reduction of leukocytosis and eosinophilia were not significant, but total IgE levels decreased significantly, in contrast to IFN-gamma levels that were significantly increased. The oxamniquine treatment of acute schistosomiasis patients is followed by an improvement of a Th1 response in vitro. If this response has a protective aspect is unknown, and some investigations need to be realized.

Análise digital de imagens da pele avaliadas pela histoquímica com lectinas: marcador potencial para alterações bioquímicas e diagnóstico diferencial de tumores / Digital image analysis of skin neoplasms evaluated by lectin histochemistry: potential marker to biochemical alterations and tumour differential diagnosis

The present study aims to evaluate, through lectin histochemistry, the alterations in the expression of cell surface carbohydrate between benign and malignant lesions of skin using computer image analysis. Skin fragments were obtained through biopsies and diagnosed as basal cell carcinoma (BCC), epidermoid carcinoma (EpC), trichoepithelioma (TE), keratoacanthoma (KA), seborrheic keratosis (SK) and actinic keratosis (AK). Lectins Con A, WGA, PNA, UEA-I and LTA were used in histochemistry study. Image analysis was carried out in a workstation using OPTIMAS TM software system. PNA strong binding pattern to studied tumours evidenced the high expression of D-galactose residues in the epidermal neoplasms when compared to other sugars recognized by the other lectins. Among benign neoplasms, KA presented a high expression of glucose/mannose, alpha-fucose and D-galactose residues evidenced by the intense staining of Con A (94.7 percent), LTA (84.2 percent) and PNA (89.4 percent), respectively. Malignant tumours showed distinct binding patterns. EpC presented significant binding only by PNA lectin. BCC was differentially stained in comparison to the staining pattern observed in benign lesions such as TE. Qualitative (lectin histochemistry) and quantitative (digital image analysis) data obtained in this study evidenced those lectins are potential markers to biochemical alterations in skin neoplasms.

O presente estudo objetivou avaliar, através da histoquímica com lectinas, as alterações na expressão dos carboidratos da superfície celular entre lesões benignas e malignas da pele usando análise de imagens computadorizadas. Fragmentos de pele foram obtidos através de biópsias e diagnosticados como carcinoma basocelular (CBC), carcinoma epidermóide (EpC), tricoepitelioma (TE), cerato acantoma (KA), ceratose seborreica (CS) e ceratose actínica (CA). As lectinas Con A, WGA, PNA, UEA-I e LTA foram usadas no estudo histoquímico. A análise de imagens foi realizada numa estação de análise usando o sistema OPTIMAS TM de análises. A PNA tem sido largamente utilizada no estudo de tumores, evidenciando a expressão de D-galactose nas neoplasias epidérmicas; esse açúcar apresenta alta expressão quando comparado com os outros reconhecidos pelas demais lectinas. Entre as neoplasias benignas, KA apresentou alta expressão glucose/manose; resíduos de alfa-fucose e D-galactose apresentaram intensa marcação com ConA (94,7%) LTA (84,2%) e PNA (89,4 %), respectivamente. Os tumores malignos mostraram marcações distintas: EpC apresentou marcaçã significativa somente com a lectina PNA; CBC apresentou diferente padrão de marcação quando comparado ao observado nas lesõs benignas assim como no TE. Os resultados qualitativos (análise de imagens) e quantitativos (histoquímica com lectinas) desse estudo evidenciaram que as lectinas têm grande potencial como marcadores de alterações bioquímicas nas neoplasias da pele.

Altered lectin-binding sites in normal colon and ulcerative colitis

O presente trabalho objetivou, através de histoquímica com lectinas e análise digital de imagens, avaliar a expressão de carboidratos em amostras de colo normal e com colite ulcerativa. A partir de fragmentos de mucosa intestinal foram obtidos cortes histológicos (4mm) que foram incubados com lectinas (Con A, WGA, LTA e PNA), e os resultados das marcações foram avaliados através de microscopia óptica e sistema de análise de imagens. Os resultados obtidos revelaram uma intensa marcação para as células inflamatórias, principalmente neutrófilos infiltrados no tecido de reto e sigmóide, bem como células das glândulas intestinais. As lectinas WGA e LTA exibiram padrões distintos de marcação entre o epitélio normal e os casos de colite ulcerativa. As lectinas PNA e Con A falharam em reconhecer os carboidratos celulares nos casos estudados em ambos os grupos. Os resultados obtidos foram confirmados pela análise de imagem. As observações obtidas sugerem que as lectinas WGA e LTA são marcadores promissores para diferenciar o epitélio normal do padrão inflamatório da colite ulcerativa, indicando uma expressão distinta de N-acetilglicosamina e L-fucose nos respectivos casos estudados.

Prevalence of IgG antibodies specific to Toxoplasma gondii among blood donors in Recife, Northeast Brazil

A serological survey of Toxoplasma gondii infection in blood donors was carried out in order to identify seroprevalence in Recife, Brazil. Sera from 160 individuals (119 male and 41 female) were evaluated by using a Toxoplasma IgG-antibody enzyme immunoassay (Denka Seiken Co., LTD., Tokyo, Japan). The seropositive percentual for males (79.0 percent) showed to be higher (p < 0.05) than for females (63.4 percent). This percentage increases with age, ranging from 18.2 percent to 92.6 percent for individuals aging under 20 and 40-50 years old, respectively. For women of childbearing age (18-40 years) it was found a prevalence of 51.6 percent

Infiltrating ductal mammary carcinoma: lectin Histochemistry study

Parkia pendula seed lectin (PpeL) was evaluated as histochemical marker for human infiltrating duct carcinoma. Concanavalin A (Con A) was used as pattern of tissue lectin binding. Tissues were treated with 0,1 por cento trypsin solution and 0,3 por cento methanol-H2. Optic microscopy waas used to evaluate the lectin-binding pattern to tissue. Methyl-a-D-mannoside, at 300nM, was used to inhibit the lectin binding to mammary tissues. The inhibition assay reinforced that Ppel conjugated to peroxidase bound to glucose and/or mannose residues in the membrane surface glycoconjugates. Distinct binding patterns of Ppel, associated to different mammary epithelium dedifferentiation, were comparable to those obtained with Con A. These findings indicate a potencial use of this lectin as histochemical marker in investigations of breast neoplasic alterations

Polyvinyl alcohol-glutaraldehyde as solid-phase in ELISA for schistosomiasis

Preparaçöes antigenicas soluveis de Schistosoma mansoni adulto (SWAP) fixadas covalentemente em discos de polivinil alcool-glutaraldeido foram usadas em teste de ELISA. As melhores condiçöes para o ensaio foram estabelecidas e foi encontrado que uma quantidade mínima de antigeno, em torno de 1,5 ug e necessária. Comparaçäo entre este procedimento e o de ELISA convencional foi estabelecida. Um metodo seguro de imobilizaçäo do antigeno foi alcançado e os baixos preços dos reagentes empregados säo economicamente atraentes...

The use of polyvinyl alcohol glutaraldehyde as solid-phase in ELISA for plague

Discs of polyvinyl alcohol cross-linked with glutaraldehyde were synthesized under acid catalysis (H2SO4). Then, the antigen F1 purified from Yersinia pestis was covalently linked to this modified polymer. Afterwards, an enzyme-linked immunosorbent assay (ELISA) was established for the diagnosis of plague in rabbit and human. The best conditions for the method were achieved by using 1.3µg of F1 prepared in 0.067 M phosphate buffer, pH 7.2, containing 1 M NaCl (PBS); anti-IgG peroxidase conjugate diluted 6,000 times and as a blocking agent 3 per cent w/v skim milk in PBS. The titration of positive rabbit serum according to this procedure detected antibody concentrations up to 1:12,800 times. The present method, the conventional ELISA and passive haemagglutination assay are compared.

The use of ferromagnetic dacron as solid-phase in enzyme immunoassays

Ferromagnetic dacron is proposed as an alternative solid-phase for magnetic enzyme immunoassays. Human serum albumin (HSA) was covalentlyimmobilized onto ferromagnetic dacron and as enzyme immunoassay was developed using anti-HSA rabbit sera. Peroxidase, o-phenylenediamine (OPD) and hydrogen peroxide were used anti-HSA rabbit sera. Peroxidase, o-phenylenediamine (OPD) and hydrogen peroxide were used as the enzymatic label and substrates, respectively. Best results were observed when particles of 63-100 µm (diameter) and 10 µg of immobilized antigen were used. Positive reactions were detected until dilutions of1:51200 of immune sera. Its reproducibility was similar to standard ELISA. Disruption of the immunocomplexes formed and recuperation of the immobilized antigen in other immunoassays also proved to be reliable

Standardization of the dot enzyme-lynked immunosorbent assay (dot-ELISA) for experimental plague

A dot enzyme linked immunosorbent assay (dot-ELISA) was previously developed to detect specific antibodies in rabbits sera immunized against FIA protein obtained from Yersina pestis. This antigen was covalently linked onto the surface of dacron (polyethyleneterephthalate). Here, standard conditions are described for the optimization of this procedure: an amount of 20 ng of FIA protein was fixed onto dacron; anti-rabbit IgG peroxidase conjugate diluted 1:8,000 and 30% non-fat instant milk as blocking substance were used throughout the method. This procedure was compared with that employing nitrocellulose as solid-phase which showed to be more sensitive. However, the method based on dacron did not show false positive reactions against non-immunized rabbits sera at low antigen amount and diluted anti-IgG peroxidase conjugate

The use of dacron plates for DOT enzyme-linked immunosorbent assay (DOT-ELISA)

Dacron (polyethylenetherephthalate) is proposed as a matrix for dot-ELISA procedures, as an alternative to nitrocellulose. Plates of dacron were partially hydrazinolyzed and hydrazide groups introduced were converted to azide groups. The derivative dacron-antigen was covalently linked on to the plates through these azide groups. The derivative dacron-antigen was exaustively washed according to CROOK and antigen was still fixed onto the plates. Protein F1A purified from Yersinia pestis was used as a model. Triration of sera from immunized and non immunized rabbits against this protein was carried out by employing the dot-ELISA method. No significant difference was observed using dacron-antigen and nitrocellulose-antigen preparations. Howwvwe, both procedures showed to have a significant better performance in comparasion with the passive hemagglutination method. The specificity and reproductibility of the dot-ELISA assay using both preparations showed a similar behaviour. Nitrocellulose preparation was stable at 4 graus Centígrados, 28 graus centígrados and -20 graus centígrados for 90 days, whereas the dacron-antigen derivative was stable only when stored at 4 graus centígrados. Dacron-antigen derivative could be re-used when the spot developing was proceeded using 4-chloro-1-naphtol as substrate