Clinical Evaluation of Efficacy of 99mTC -Ethambutol in Tubercular Lesion Imaging

Purpose. The aim of this work was to develop specific radiopharmaceutical and to evaluate its efficacy in human to detect and locate the tubercular lesion. Materials and Methods. 99mTc-Ethambutol (EMB) was produced by direct labeling method. In vitro and in vivo biological studies and animal experiments were done. Phase I Clinical trial was performed. As per plan, 2 normal human subjects for biodistribution studies and fourteen patients (8 males and 6 females; age range of 25–50, with one patient aged 12 years as an exception) were chosen for clinical trial. Whole body scan and spots were acquired at 1 hour and 4 hour. Angiography, blood pool, and 24-hours spot images of the infected areas were also acquired. Result. Radiolabeling yielded >85% of labeled complex. In vitro and in vivo biological studies and animal experiments indicated 99mTc-EMB as a specific tuberculosis imaging agent. The biodistribution study in normal human subjects suggested stability of 99mTc-EMB, with main excretory pathways being renal and hepatobiliary, which appeared to be similar to the known behavior of unlabeled EMB. No adverse reactions were observed. 99mTc-EMB got localized in pulmonary and bone tubercular lesions. Scintigrams of 99mTc-EMB and 99mTc-Ciprofloxacin were compared at different time intervals. Conclusion. The present study states that developed 99mTc-EMB has high potential to qualify as a specific tuberculosis imaging radiopharmaceutical and is safe for human use

Molecular rationale for the use of PI3K/AKT/mTOR pathway inhibitors in combination with crizotinib in ALK-mutated neuroblastoma

Mutations in the ALK tyrosine kinase receptor gene represent important therapeutic targets in neuroblastoma, yet their clinical translation has been challenging. The ALKF1174L mutation is sensitive to the ALK inhibitor crizotinib only at high doses and mediates acquired resistance to crizotinib in ALK-translocated cancers. We have shown that the combination of crizotinib and an inhibitor of downstream signaling induces a favorable response in transgenic mice bearing ALKF1174L/MYCN-positive neuroblastoma. Here, we investigated the molecular basis of this effect and assessed whether a similar strategy would be effective in ALK-mutated tumors lacking MYCN overexpression. We show that in ALK-mutated, MYCN-amplified neuroblastoma cells, crizotinib alone does not affect mTORC1 activity as indicated by persistent RPS6 phosphorylation. Combined treatment with crizotinib and an ATP-competitive mTOR inhibitor abrogated RPS6 phosphorylation, leading to reduced tumor growth and prolonged survival in ALKF1174L/MYCN-positive models compared to single agent treatment. By contrast, this combination, while inducing mTORC1 downregulation, caused reciprocal upregulation of PI3K activity in ALK-mutated cells expressing wild-type MYCN. Here, an inhibitor with potency against both mTOR and PI3K was more effective in promoting cytotoxicity when combined with crizotinib. Our findings should enable a more precise selection of molecularly targeted agents for patients with ALK-mutated tumors

Linezolid Pharmacokinetics and Its Association with Adverse Drug Reactions in Patients with Drug-Resistant Pulmonary Tuberculosis

We evaluated the relationship between the pharmacokinetic parameters of linezolid (LZD) and development of adverse drug reactions (ADRs) in patients with pulmonary drug-resistant tuberculosis. A prospective cohort of adults with pulmonary multidrug-resistant tuberculosis with additional resistance to fluoroquinolone (MDR-TBFQ+) received treatment with bedaquiline, delamanid, clofazimine, and LZD. Blood samples were collected during weeks 8 and 16 at eight time points over 24 h. The pharmacokinetic parameters of LZD were measured using high-performance liquid chromatography and associated with ADRs. Of the 165 MDR-TBFQ+ patients on treatment, 78 patients developed LZD-associated anemia and 69 developed peripheral neuropathy. Twenty-three patients underwent intense pharmacokinetic testing. Plasma median trough concentration was 2.08 µg/mL and 3.41 µg/mL, (normal 0-24 was 184.5 µg/h/mL and 240.5 µg/h/mL at weeks 8 and 16, respectively, showing a linear relationship between duration of intake and plasma levels. Nineteen patients showed LZD-associated ADRs-nine at week 8, twelve at week 16, and two at both weeks 8 and 16. Thirteen of the nineteen had high plasma trough and peak concentrations of LZD. A strong association between LZD-associated ADRs and plasma LZD levels was noted. Trough concentration alone or combinations of trough with peak levels are potential targets for therapeutic drug monitoring