Phenotypic and Functional Analysis of HL-60 Cells Used in Opsonophagocytic-Killing Assay for Streptococcus pneumoniae

Differentiated HL-60 is an effector cell widely used for the opsonophagocytic-killing assay (OPKA) to measure efficacy of pneumococcal vaccines. We investigated the correlation between phenotypic expression of immunoreceptors and phagocytic ability of HL-60 cells differentiated with N,N-dimethylformamide (DMF), all-trans retinoic acid (ATRA), or 1alpha, 25-dihydroxyvitamin D3 (VitD3) for 5 days. Phenotypic change was examined by flow cytometry with specific antibodies to CD11c, CD14, CD18, CD32, and CD64. Apoptosis was determined by flow cytometry using 7-aminoactinomycin D. Function was evaluated by a standard OPKA against serotype 19F and chemiluminescence-based respiratory burst assay. The expression of CD11c and CD14 gradually increased upon exposure to all three agents, while CD14 expression increased abruptly after VitD3. The expression of CD18, CD32, and CD64 increased during differentiation with all three agents. Apoptosis remained less than 10% until day 3 but increased after differentiation by DMF or ATRA. Differentiation with ATRA or VitD3 increased the respiratory burst after day 4. DMF differentiation showed a high OPKA titer at day 1 which sustained thereafter while ATRA or VitD3-differentiated cells gradually increased. Pearson analysis between the phenotypic changes and OPKA titers suggests that CD11c might be a useful differentiation marker for HL-60 cells for use in pneumococcal OPKA.

Phenotypic and Functional Analysis of HL-60 Cells Used in Opsonophagocytic-Killing Assay for Streptococcus pneumoniae

Differentiated HL-60 is an effector cell widely used for the opsonophagocytic-killing assay (OPKA) to measure efficacy of pneumococcal vaccines. We investigated the correlation between phenotypic expression of immunoreceptors and phagocytic ability of HL-60 cells differentiated with N,N-dimethylformamide (DMF), all-trans retinoic acid (ATRA), or 1alpha, 25-dihydroxyvitamin D3 (VitD3) for 5 days. Phenotypic change was examined by flow cytometry with specific antibodies to CD11c, CD14, CD18, CD32, and CD64. Apoptosis was determined by flow cytometry using 7-aminoactinomycin D. Function was evaluated by a standard OPKA against serotype 19F and chemiluminescence-based respiratory burst assay. The expression of CD11c and CD14 gradually increased upon exposure to all three agents, while CD14 expression increased abruptly after VitD3. The expression of CD18, CD32, and CD64 increased during differentiation with all three agents. Apoptosis remained less than 10% until day 3 but increased after differentiation by DMF or ATRA. Differentiation with ATRA or VitD3 increased the respiratory burst after day 4. DMF differentiation showed a high OPKA titer at day 1 which sustained thereafter while ATRA or VitD3-differentiated cells gradually increased. Pearson analysis between the phenotypic changes and OPKA titers suggests that CD11c might be a useful differentiation marker for HL-60 cells for use in pneumococcal OPKA.

Evaluation of the antimicrobial activity of various concentrations of Tulsi (Ocimum sanctum) extract against Streptococcus mutans: An in vitro study.

Aim: To determine if Tulsi (Ocimum sanctum) extract has an antimicrobial activity against Streptococcus mutans and to determine which concentration of Tulsi (Ocimum sanctum) extract among the 15 concentrations investigated has the maximum antimicrobial activity. Setting and Design: Experimental design, in vitro study, Lab setting. Materials and Methods: Ethanolic extract of Tulsi was prepared by the cold extraction method. The extract was then diluted with an inert solvent, dimethyl formamide, to obtain 15 different concentrations (0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7% 8%, 9%, 10%) of the extract. 0.2% chlorhexidine was used as a positive control and dimethyl formamide was used as a negative control. The extract, along with the controls, was then subjected to microbiological investigation to determine which concentration among the 15 different concentrations of the extract gave a wider inhibition zone against Streptococcus mutans. The zones of inhibition were measured in millimeters using a vernier caliper. Results: At the 4% concentration of Tulsi extract, a zone of inhibition of 22 mm was obtained. This was the widest zone of inhibition observed among all the 15 different concentrations of Tulsi that were investigated. Conclusion: Tulsi extract demonstrated an antimicrobial property against Streptococcus mutans.

Hepatotoxicidade da dimetilformamida / Hepatotoxicity of dimethylformamide

A dimetilformamida é uma substância amplamente utilizada nos dias atuais, apresentando um amplo espectro de aplicações na indústria moderna. Este estudo busca abordar seus efeitos toxicofarmacológicos especificamente sobre o fígado, sua relação com os riscos ocupacionais, as medidas de proteção à saude do trabalhador e as opções terapêuticas atuais.