The development of internal pressure standards for in-house elastic wave velocity measurements in multi-anvil presses

Ultrasonic systems are powerful tools to determine elastic wave velocities of minerals and materials at high pressure and temperature and have been extensively developed in recent decades. However, accurate measurement of sample length is required to convert travel times into wave velocities, limiting their use to synchrotron facilities or room temperature experiments in laboratories. We have made use of a close collaboration between the Bayerisches Geoinstiut and the P61B end-station beamline (PETRA III - DESY) to install ultrasonic systems and develop a novel dual travel time method for in situ pressure determination without the need for synchrotron radiation. Our method relies on the travel times of elastic waves through a reference material; it requires a thermocouple and is non-intrusive, with the reference material replacing the backing plate of the high-pressure assembly. Pressures obtained from this dual travel time method show excellent agreement with those obtained from x-ray diffraction using synchrotron radiation on standard materials. Our novel method enables in situ pressure determination at varying temperatures during in-house ultrasonic interferometry experiments. This allows us not only to determine the elastic behavior of minerals and materials but also to investigate phase diagrams, solidus, or liquidus conditions at varying pressures and temperatures during in-house experiments. During the installation of the pulse-echo ultrasonic system, we identified critical parameters for obtaining reliable data. While these requirements are well-known to experts, this study presents a comprehensive review of the different characteristics of ultrasonic systems, providing user-friendly guidelines for new users installing and operating such systems in high-pressure and high-temperature conditions.

Adverse Events and Subsequent Management Associated With Eustachian Tube Balloon Dilation

Objective

Eustachian tube balloon dilation is a minimally invasive technique used to improve persistent Eustachian tube dysfunction. Currently, the US Food and Drug Administration (FDA) has approved the use of balloon dilation devices produced by three manufacturers, but little is known about associated adverse events and subsequent management.

Study Design

Case series.

Setting

FDA Manufacturer and User Facility Device Experience (MAUDE) database.

Methods

Reports submitted to the FDA using the MAUDE database searched from January 2000 to July 2022 were analyzed for adverse events and management.

Results

A total of 13 adverse events were found in the database. Subcutaneous emphysema (n = 8) was the most common event. Other less frequent events included patulous Eustachian tube (n = 2), vascular dissection (n = 1), nasopharyngeal mucocele (n = 1), and tinnitus (n = 1). A majority of patients who experienced subcutaneous emphysema received antibiotics (n = 5) and were admitted to the hospital (n = 4). The patient with a carotid dissection 7 days postprocedure presented with a stroke and fully recovered after stent placement. There was limited preprocedure information in the MAUDE database. There were 2 patients who did not fully recover after a complication. Three patients underwent corrective surgical interventions. No one company had more associated adverse events reported.

Conclusion

Subcutaneous emphysema is the most common adverse event after Eustachian tube dilation. Further studies exploring potential balloon dilation adverse events to allow for better patient counseling are warranted.

P-478 Deleterious influence of cyclophosphamide on primordial follicles derives from increased DNA damage and reduced proliferation in xenotransplanted human ovarian tissue

Study question

What are the acute effects of cyclophosphamide (Cp) on primordial follicles (PrFs) in human ovarian tissue?

Summary answer

Administration of Cp damages PrFs via DNA fragmentation and results in reduced proliferation with no increase in PrF activation markers.

What is known already

Alkylating agents are highly gonadotoxic, and in cases where freezing oocytes, embryos, or ovarian tissue is impractical, a better understanding of the underlying damage mechanism could enable development of fertoprotective approaches (1). Studies from different groups suggest conflicting mechanisms of ovarian damage, with either PrF activation (2) or cell damage and apoptosis (3-4) proposed as drivers of PrF depletion. Few studies have examined this question using human tissue. We performed xenografts using ovarian tissue from a 17-month-old girl to ensure a graft with plentiful PrFs to test the acute effect of Cp.

Study design, size, duration

Cross-sectional study.

We utilized a xenotransplantation model in which human ovarian tissue is co-transplanted with endothelial cells (ECs) into immunocompromised mice (NSG) (5). Three weeks after xenotransplantation, time 0, intraperitoneal (IP) injection of (saline/Cp) was followed by an IP injection of ethynyl-deoxyuridine (Edu), at 0 and 24 hours, followed by 5-chloro-2′-deoxyuridine (CldU), at 48 and 72 hours. Grafts were harvested at 96 hours.

Participants/materials, setting, methods

We co-xenotransplanted human ovarian cortical tissue from a 17-month-old girl, cryopreserved for fertility preservation, into immunocompromised mice. After 3 weeks, Cp (75mg/Kg)/saline was administered IP. Mice were then sequentially injected with EdU, followed by CldU (both at 100mg/kg for 2 days) 24 hours apart. Twenty-four hours later, mice were sacrificed and xenografts were harvested and sectioned. Slides were stained for EdU, CldU, VASA, γ-H2AX, FOXO3a, and 4',6-Diamidino-2-Phenylindole-Dilactate (DAPI) and imaged using a confocal microscope.

Main results and the role of chance

We used anti-VASA staining to evaluate oocyte morphology, confirming that chemotherapy was not sterilizing; we counted 76.5% of morphologically normal PrF in the control group (Ctrl) (130/170) and 35.1% (13/37) in the Cp group. In the Ctrl group, 11% stained positively for DNA fragmentation using anti-γ-H2AX, whereas 43% were positive in the Cp group (p = 0.0073). To evaluate activation, we stained for FOXO3a in the oocyte nucleus. No difference was found between the groups: 52.4% (74/144) versus 44.6% (37/83) in Ctrl versus Cp, respectively. Interestingly, when comparing EdU incorporation, the Ctrl group had higher incorporation at 72%, versus the Cp group with 40% of incorporation (p = 0.0485), and no difference was found with CldU incorporation: Ctrl 22% versus 27% in the Cp group, respectively (P = 0.6960).

Limitations, reasons for caution

We measured acute effects, DNA fragmentation, and proliferation, at five days post-Cp administration; however, this falls short of evaluating processes that appear later (fibrosis and neovascularization). Also, the results may partly stem from the patient’s young age. Repeating the experiment using adult-derived tissue might yield different results.

Wider implications of the findings

A better understanding of both the timeline and underlying mechanisms that contribute to chemotherapy-related gonadotoxicity could diminish the damage and depletion of the ovarian reserve (PrF). These results provide evidence that direct damage to PrFs, and not increased activation, contributes to gonadotoxicity in the acute phase following administration of Cp.

Trial registration number

NA

Microbiomics of irrigation with xylitol or Lactococcus lactis in chronic rhinosinusitis

OBJECTIVE

Topical sinonasal rinse therapies may alter the local microbiome and improve disease control in chronic rhinosinusitis (CRS). The objective of this study was to examine microbiome changes in post-surgical CRS patients when rinsing with commercially available products containing xylitol or Lactococcus lactis.

METHODS

A crossover-type protocol with a washout period was designed. Swab samples from anterior ethmoid cavities of CRS patients were collected prospectively at baseline. Subjects were provided packets containing either L. lactis W136 or xylitol in non-blinded fashion and instructed to add it to their rinse bottles daily for 28 days, after which another swab was taken. A saline wash-out period was completed and a third swab taken. A final 28-day regimen of the opposite product was followed by a final swab. DNA extraction and sequencing of the 16S rRNA gene allowed for global microbiome analysis.

RESULTS

We enrolled 25 subjects with CRS and 10 controls resulting in 70 adequate samples. Increased detection of Lactococcus was observed after use of L. lactis. No significant trends in alpha or beta diversity as a result of treatment were observed. SNOT-22 score did not change significantly following treatment with xylitol, L. lactis, or saline.

CONCLUSION

We did not detect any major clinical or microbiome-level effect due to treatment with two topical rinse products. Further research is needed to elucidate their clinical utility and possible probiotic effect.

LEVEL OF EVIDENCE

3.

The effect of methylprednisolone pulse therapy in polymyositis/dermatomyositis

The study aim was to assess the effect of corticosteroid (CS) therapy on the clinical and biological features of dermatomyositis (DM) or polymyositis (PM).