Description of Particle Size, Distribution, and Behavior of Talc Preparations Commercially Available Within the United States

Video-assisted thoracoscopic surgery pleurectomy: a suitable alternative for treating malignant pleural effusions

Background

Malignant pleural effusions (MPEs) are common manifestations of metastatic cancers and are associated with a dismal prognosis. Talc pleurodesis has been proven to be effective in the management of MPEs, however, class-action lawsuits linking talc to ovarian adenocarcinoma have rendered it unavailable at many institutions. As a result, surgeons have resorted to less effective chemical pleurodesis as an alternative to indwelling pleural drainage catheters. Given the absence of talc, we explored the effectiveness of video-assisted thoracoscopic surgery (VATS) partial pleurectomy (VPP) for treating MPEs.

Methods

We performed a retrospective review of patients with MPEs managed after talc became unavailable at our institution. Between 2016 and 2018, we identified five patients who refused pleural drainage catheters and underwent VPP. Symptoms at presentation included fatigue, dyspnea, and pleuritic chest pain. All had unilateral MPEs (left n=3, right n=2). VPP included removal of parietal surfaces of the pleura other than the pleura overlying the subclavian vessels, the mediastinum, and the lung viscera.

Results

There were no significant perioperative adverse events and post-operative pain was well controlled. Chest tubes were removed between post-operative day (POD) 3 and 7. Follow-up time ranged from four to 36 weeks. All patients had symptomatic relief and radiographic evidence of improved MPEs. No patients required re-interventions. One patient expired six months after surgery while the remaining four were alive at last follow-up.

Conclusions

VPP offers an effective alternative to chemical pleurodesis for managing MPEs in patients who prefer to avoid pleural drainage catheters.

Analytic comparison of talc in commercially available baby powder and in pelvic tissues resected from ovarian carcinoma patients

OBJECTIVE

Measure the size and shape of talc particles in talcum powder and compare this data to the size and shape of talc particles found in surgically resected tissues from patients with ovarian carcinoma.

METHODS

Using polarized light microscopy (PLM) and scanning electron microscopy (SEM), we measured the size and shape of talc particles in samples of talc-containing baby powder (TCBP) and surgically resected pelvic tissues (hysterectomies) from talc-exposed patients with ovarian carcinoma.

RESULTS

The most frequent class of particles in TCBP can be unequivocally identified as talc, using both polarized light microscopy and scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX). The talc particles found in resected tissues from ovarian carcinoma patients are similar in size and shape to the most abundant morphological class of particles in TCBP.

CONCLUSIONS

This finding, combined with previous epidemiological literature and tissue-based analytical studies, provides further evidence that the small, isodiametric particles that dominate TCBP can migrate from the perineum and become lodged in distal structures in the female reproductive tract, where they may lead to an increased risk of developing ovarian carcinoma.

Jet-paddling jellies: swimming performance in the Rhizostomeae jellyfish Catostylus mosaicus

Jellyfish are a successful and diverse class of animals that swim via jet propulsion, with swimming performance and propulsive efficiency being related to the animal's feeding ecology and body morphology. The Rhizostomeae jellyfish lack tentacles but possess four oral lobes and eight trailing arms at the centre of their bell, giving them a body morphology quite unlike that of other free-swimming medusae. The implications of this body morphology on the mechanisms by which thrust is produced are unknown. Here, we determined the wake structure and propulsive efficiency in the blue-blubber jellyfish Catostylus mosaicus (order: Rhizostomeae). The animal is propelled during both bell contraction and bell relaxation by different thrust-generating mechanisms. During bell contraction, a jet of fluid is expelled from the subumbrellar cavity, which results from the interaction between the counter-rotating stopping (from the preceding contraction cycle) and starting vortices, creating a vortex superstructure and propulsion. This species is also able to utilise passive energy recapture, which increases the animal's swimming velocity towards the end of the bell expansion phase when the bell diameter is constant. The thrust produced during this phase is the result of the flexible bell margin manoeuvring the stopping vortex into the subumbrellar cavity during bell relaxation, enhancing its circulation, and creating a region of high pressure on the inner surface of the bell and, consequently, thrust. These mechanisms of thrust generation result in C. mosaicus having a relatively high propulsive efficiency compared with other swimmers, indicating that economical locomotion could be a contributing factor in the ecological success of these medusan swimmers.