Purified talc powder

BACKGROUND: Patients with suspected malignant pleural effusions (MPE) are often in need of both a confirmatory diagnosis and symptom control. Therapeutic options include talc pleurodesis via chest drain, poudrage during medical thoracoscopy, or alternatively an indwelling pleural catheter (IPC). Combining the diagnostic and therapeutic efficacy of medical thoracoscopy and poudrage with the ambulatory benefits of an IPC has not been studied within a randomised controlled trial. The aim of the TACTIC trial was to determine whether this approach resulted in a reduced length of hospital stay and improvements in dyspnoea. METHODS: This unblinded, phase 3, randomised controlled trial was undertaken in 11 UK hospitals. Patients with MPE and confirmed malignancy (during medical thoracoscopy or beforehand) received talc poudrage and were randomly assigned by a centralised web-based system to an IPC at the time of medical thoracoscopy or usual care (ie, medical thoracoscopy, poudrage, and admission with large bore tube). Co-primary outcomes were time in hospital (including initial admission for trial procedure and any subsequent readmissions over 4 weeks post procedure) and average breathlessness assessed with visual analogue scale dyspnoea scores, measuring severity of dyspnoea from 0 mm to 100 mm, over a 4-week period. All randomised patients in whom an outcome was available were included in the analysis on a modified intention-to-treat basis. TACTIC was registered with ISRCTN on Aug 8, 2021 (ISRCTN11058680). FINDINGS: Participants were recruited from between Dec 15, 2021, and Jan 3, 2024. 124 participants were randomised: 62 to the intervention and 62 to standard care. Leading diagnoses were pleural mesothelioma (46%), lung cancer (28%), and breast cancer (10%). Co-primary outcome data were available for 102 patients for total length of hospital stay (52 in intervention group vs 50 in standard care group) and 108 patients for breathlessness (57 vs 51). Median time in hospital was 1 day (IQR 1-3, 95% CI 1-2) in the intervention group versus 2 days (IQR 1-3, 95% CI 1-2) in standard care group (p=0·26). Median visual analogue scale dyspnoea scores did not differ between groups: 14·0 mm (IQR 8·8-32·4) in the intervention group versus 19·6 mm (8·1-38·7) in standard care group (p=0·26). Participants in the intervention group required fewer additional invasive pleural procedures by 12 weeks (two [3%] of 60 vs 19 [34%] of 56, p<0·0001) Trial related adverse events rates were similar in both groups (46 [74%] of 62 vs 44 [71%] of 62, p=0·84). Three related serious adverse events were recorded, all occurring in the intervention group. INTERPRETATION: The combination of medical thoracoscopy, poudrage, and IPC did not result in shorter hospital stay but was safe and resulted in similar dyspnoea control compared with standard care. For patients with symptomatic MPE undergoing medical thoracoscopy for pleurodesis who prioritise minimising the length of hospital stay or the need for further invasive pleural procedures, the addition of an IPC alongside poudrage might help to achieve this goal. FUNDING: National Institute of Health Research, Research for Patient Benefit.

Abstract licence: CC BY

Long noncoding RNAs (lncRNAs) have emerged as new regulatory molecules implicated in diverse biological processes, including therapeutic resistance. However, the mechanisms underlying lncRNA-mediated temozolomide (TMZ) resistance in glioblastoma (GBM) remain largely unknown. To illustrate the role of lncRNA in TMZ resistance, we induce TMZ-resistant GBM cells, perform a lncRNA microarray of the parental and TMZ-resistant cells, and find an unreported lncRNA in GBM, lnc-TALC (temozolomide-associated lncRNA in glioblastoma recurrence), correlated with TMZ resistance via competitively binding miR-20b-3p to facilitate c-Met expression. A phosphorylated AKT/FOXO3 axis regulated lnc-TALC expression in TMZ-resistant GBM cells. Furthermore, lnc-TALC increased MGMT expression by mediating the acetylation of H3K9, H3K27 and H3K36 in MGMT promoter regions through the c-Met/Stat3/p300 axis. In clinical patients, lnc-TALC is required for TMZ resistance and GBM recurrence. Our results reveal that lnc-TALC in GBM could serve as a therapeutic target to overcome TMZ resistance, enhancing the clinical benefits of TMZ chemotherapy.

Abstract licence: CC BY

Talc is a naturally hydrophobic gangue mineral in most sulfide ores. However, talc has vast applications in the cosmetics, paper, and paint industries due to its high chemical stability, and its demand continues to grow. Since flotation is the most effective beneficiation technique for upgrading sulfides, the high hydrophobicity of talc has made its selective separation challenging. This paper explored the different properties of talc and the different factors that affect its flotation separation performance as a proven versatile beneficiation technique. Surface properties, zeta potential measurements, contact angles, and other factors affecting the talc flotation efficiency were discussed in detail. It was observed that the surface face/edge ratio (particle size) has a direct relationship with the level of talc hydrophobicity. Talc surfaces are negatively charged in a wide pH range (pH 2–12). Different depressants have already been studied; however, most of them showed low selectivity. The addition of ions such as Ca2+ could enhance talc depression. Pretreatment methods such as ultrasonic and thermal treatments were reported to decrease the talc floatability. It was demonstrated that the development of new selective depressants or pretreatment options for talc flotation requires attention in future investigations to improve its selective separation.

Abstract licence: CC BY

The fused filament fabrication (FFF) process is characterized by fast local temperature decrease. Such characteristic usually leads to lower crystallinity degree in final printed parts when semi-crystalline polymers are used. By melt-compounding poly(lactic acid) (PLA) with its nucleating agent Talc, filaments of PLA/Talc composite were produced and used in FFF. Through investigations in static/dynamic mechanical and thermal properties, and morphology, the influence of Talc on the PLA based composite in FFF are revealed: after melt compounding with Talc, PLA matrix can crystallize considerably during fast cooling in FFF; as a consequence, final parts exhibited higher degree of crystallinity than the case of neat PLA; furthermore, melt crystallization process releases heat, promoting coalescence between adjacent layers, and ultimately contributes to higher parts stiffness and better mechanical integrity. This paper presents a first example in which in-situ melt crystallization is recovered for semi-crystalline polymers during FFF via composition modification. With this example, an increase in crystallinity from 3.6% to 12% can lead to 15% increase in flexural modulus for FFF printed parts. Research results also provide insights in material property reinforcement, heat treatment on finished parts, and explorations in other semi-crystalline materials in FFF.

Abstract licence: CC BY-NC-ND