RESUMO
The gold standard method for diagnosis of tuberculosis is the isolation of Mycobacterium tuberculosis through culture, but there is a probability of cross-contamination in simultaneous cultures of samples causing false-positives. This can result in delayed treatment of the underlying disease and drug side effects. In this paper, we reviewed studies on falsepositive cultures of M. tuberculosis . Rate of occurrence, effective factors, and extent of false-positives were analyzed. Ways to identify and reduce the false-positives and management of them are critical for all laboratories. In most cases, falsepositive is occurring in cases with only one positive culture but negative direct smear. The three most crucial factors in this regard are inappropriate technician function, contamination of reagents, and aerosol production. Thus, to reduce false-positives, good laboratory practice, as well as use of whole-genome sequencing or genotyping of all positive culture samples with a robust, extra pure method and rapid response, are essential for minimizing the rate of false-positives. Indeed, molecular approaches and epidemiological surveillance can provide a valuable tool besides culture to identify possible false positives.
RESUMO
Aim: The present study was conducted to survey the potential cytotoxic influence of freeze-dried aqueous extract of its fruits on gastrointestinal cell lines, namely AGS [human gastric carcinoma] and KYSE30 [human esophageal squamous cell carcinoma]
Background: Rosemary [Rosmarinus officinalis] is a wild medicinal plant shown to have anticancer activity. Carnosic and rosmarinic acids are compounds, obtained from it through several extraction methods
Methods: The aqueous extract of the fruits of R.officinalis was freeze-dried, and KYSE30 and AGS cancer cell lines were treated with crude extract. Cytotoxic effect of the extracts on the cell lines was examined using 3-[4, 5-Dimethylthiazol-2-yl]-2, 5- diphenyltetrazolium bromide [MTT] and neutral red assay. Apoptotic cells were detected with ethidium bromide/acridine orange [EB/AO]. Cell-cycle distributions were evaluated by flow cytometry
Results: IC50 values were 4.1, 1.8 and 1.3 mg/mL for AGS cell lines after 24, 48 and 72 hours by MTT assay, respectively, and 4.4, 2.1 and 1.1 mg/mL by neutral red assay, respectively. IC50 values for KYSE30 cell lines were 600, 180 and 150 mg/mL after 24, 48 and 72 hours by MTT assay, and 860, 270 and 230 mg/mL by neutral red. EB/AO staining increased in apoptotic cells. After 24 h of treatment at different concentrations, significant increases and decreases in population were shown at G2/M and G1 phases, respectively
Conclusion: The aqueous extract of the fruits of R.officinalis was freeze-dried, and KYSE30 and AGS cancer cell lines were treated with crude extract. Cytotoxic effect of the extracts on the cell lines was examined using 3-[4, 5-Dimethylthiazol-2-yl]-2, 5- diphenyltetrazolium bromide [MTT] and neutral red assay. Apoptotic cells were detected with ethidium bromide/acridine orange [EB/AO]. Cell-cycle distributions were evaluated by flow cytometry