Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Cervical lymph node metastasis of bladder cancer: a case report and review of literature

AbstractObjective To report an extremely rare case of bladder cancer patient with cervical lymph nodes, abdominal lymph nodes, and bone metastases at the same time.Methods and results The case was investigated by follow-up and immunohistochemistry was used in the pathological part.Result The patient was diagnosed with bladder cancer (high-grade urothelial metastatic epithelial cell carcinoma) by pathology and immunohistochemistry after transurethral resection of bladder tumor (TURBT) and metastatic bladder cancer by pathology and immunohistochemistry after cervical lymph node aspiration due to neck lymph node enlargement 1 year later, and a CT of the chest and abdomen suggested that the patient also had abdominal lymph node and bone metastases.At the 2.5-year regular chemotherapy follow-up, the patient showed that the abdominal lymph node metastasis disappeared, the cervical lymph node fusion shrank, and the bone metastasis still existed.Conclusion 1. Regular postoperative review is particularly important; 2.For patients with UCB who undergo TURBT, a effective regular perfusion program should be performed throughout the postoperative period; 3. For patients with postoperative metastatic symptoms of UCB, Complex treatment has a positive effect on patient prognosis; 4.The presence of enlarged head and neck lymph nodes in patients with bladder cancer should also be considered as metastatic of UCB