Safety and Efficacy of Renuvion Helium Plasma to Improve the Appearance of Loose Skin in the Neck and Submental Region.

BACKGROUND: Minimally invasive procedures that deliver thermal energy to subcutaneous tissue offer a solution when deciding between excisional and noninvasive options to address face and neck aging-related changes. A minimally invasive helium plasma device, Renuvion, was first utilized for subdermal tissue heating to reduce skin laxity under an FDA general clearance for cutting, coagulation, and ablation of soft tissue. OBJECTIVES: The purpose of this study was to demonstrate the safety and effectiveness of the helium plasma device for improving the appearance of loose skin in the neck and submental region. METHODS: Patients undergoing the procedure with the helium plasma device in the neck and submentum were studied. They were seen for 6 months following the procedure. The primary effectiveness endpoint for improvement in lax skin in the treatment area was determined by 2 of 3 blinded photographic reviewers. The primary safety endpoint was the level of pain after treatment. RESULTS: The primary effectiveness endpoint was met; 82.5% demonstrated improvement at Day 180. The primary safety endpoint was met; 96.9% of patients experienced no pain to moderate pain to Day 7. There were no serious adverse events reported related to the study device or procedure. CONCLUSIONS: The data demonstrate benefit to patients by improvement of the appearance of lax skin in the neck and submental region. Outcomes resulted in US Food and Drug Administration 510(k) clearance in July 2022, expanding indications for the device to include subcutaneous dermatological and aesthetic procedures to improve the appearance of loose skin in the neck and submental region.

Air Medical Transport of a 12-Year-Old Girl With Cerebral Gas Embolism Due to Helium Inhalation.

This case report describes the initial care and transport considerations of a pediatric patient who suffered from cerebral gas embolism sustained after inhalation of helium from a pressurized tank. The patient demonstrated neurologic symptoms necessitating hyperbaric oxygen therapy and required fixed wing air transport across a mountain range from a rural community hospital to a tertiary center for the treatment. We review the pathophysiology of cerebral gas embolism and strategies for transporting patients with cerebral gas embolism and other trapped gas.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery.

BACKGROUND: This is the second update of a Cochrane Review first published in 2013 and last updated in 2017. Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum. OBJECTIVES: To assess the safety, benefits, and harms of different gases (e.g. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic abdominal or gynaecological pelvic surgery. SEARCH METHODS: We searched CENTRAL, Ovid MEDLINE, Ovid Embase, four other databases, and three trials registers on 15 October 2021 together with reference checking, citation searching, and contact with study authors to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included 10 RCTs, randomising 583 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (four trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. All the RCTs were single-centre studies. Four RCTs were conducted in the USA; two in Australia; one in China; one in Finland; one in Iran; and one in the Netherlands. The mean age of the participants ranged from 27.6 years to 49.0 years. Four trials randomised participants to nitrous oxide pneumoperitoneum (132 participants) or carbon dioxide pneumoperitoneum (128 participants). None of the trials was at low risk of bias. The evidence is very uncertain about the effects of nitrous oxide pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto odds ratio (OR) 2.62, 95% CI 0.78 to 8.85; 3 studies, 204 participants; very low-certainty evidence), or surgical morbidity (Peto OR 1.01, 95% CI 0.14 to 7.31; 3 studies, 207 participants; very low-certainty evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (4 studies, 260 participants; very low-certainty evidence). Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. The evidence is very uncertain about the effects of helium pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto OR 1.66, 95% CI 0.28 to 9.72; 3 studies, 128 participants; very low-certainty evidence), or surgical morbidity (5 studies, 177 participants; very low-certainty evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (3 studies, 128 participants; very low-certainty evidence). One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at high risk of bias. There were no cardiopulmonary complications, serious adverse events, or deaths observed related to either room air or carbon dioxide pneumoperitoneum.    AUTHORS' CONCLUSIONS: The evidence is very uncertain about the effects of nitrous oxide, helium, and room air pneumoperitoneum compared to carbon dioxide pneumoperitoneum on any of the primary outcomes, including cardiopulmonary complications, surgical morbidity, and serious adverse events. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established, especially in people with high anaesthetic risk.

Efficacy and Safety of Percutaneous Argon-Helium Cryoablation for Hepatocellular Carcinoma Abutting the Diaphragm.

PURPOSE: To evaluate the efficacy and safety of percutaneous argon-helium cryoablation (CA) for hepatocellular carcinoma (HCC) abutting the diaphragm (<5 mm). MATERIALS AND METHODS: A total of 61 consecutive patients (50 men, 11 women; mean age, 56.3 ± 12.1 years old; range, 32-83 years) with 74 HCC tumors (mean size, 3.3 ± 1.7 cm; range, 0.8-7 cm) who were treated with percutaneous argon-helium CA were enrolled in this retrospective study. Adverse events were evaluated according to Common Terminology Criteria for Adverse Events, version 5.0. Local tumor progression (LTP) and overall survival (OS) were analyzed using the Kaplan-Meier method and the log-rank test. The risk factors associated with OS and LTP were evaluated using univariate and multivariate Cox regression analysis. RESULTS: No periprocedural (30-day) deaths occurred. A total of 29 intrathoracic adverse events occurred in 24 of the 61 patients. Major adverse events were reported in 5 patients (pleural effusion requiring catheter drainage in 4 patients and pneumothorax requiring catheter placement in 1 patient). Median follow-up was 18.7 months (range, 2.3-60.0 months). Median time to LTP after CA was 20.9 months (interquartile range [IQR], 14.1-30.6 months). Median times of OS after CA and diagnosis were 27.3 months (IQR, 15.1-45.1 months) and 40.9 months (interquartile range, 24.8-68.6 months), respectively. Independent prognostic factors for OS included tumor location (left lobe vs right lobe; hazard ratio [HR], 2.031; 95% confidence interval [CI], 1.062-3.885; P = .032) and number of intrahepatic tumors (solitary vs multifocal; HR, 2.684; 95% CI, 1.322-5.447; P = .006). Independent prognostic factors for LTP included age (HR, 0.931; 95% CI, 0.900-0.963; P  < .001), guidance modality (ultrasound vs computed tomography and US; HR, 6.156 95% CI, 1.862-20.348; P  =   .003) and origin of liver disease. CONCLUSIONS: Percutaneous argon-helium CA is safe for the treatment of HCC abutting the diaphragm, with acceptable LTP and OS.

Inert gas narcosis in scuba diving, different gases different reactions.

PURPOSE: Underwater divers face several potential neurological hazards when breathing compressed gas mixtures including nitrogen narcosis which can impact diver's safety. Various human studies have clearly demonstrated brain impairment due to nitrogen narcosis in divers at 4 ATA using critical flicker fusion frequency (CFFF) as a cortical performance indicator. However, recently some authors have proposed a probable adaptive phenomenon during repetitive exposure to high nitrogen pressure in rats, where they found a reversal effect on dopamine release. METHODS: Sixty experienced divers breathing Air, Trimix or Heliox, were studied during an open water dive to a depth of 6 ATA with a square profile testing CFFF measurement before (T0), during the dive upon arriving at the bottom (6 ATA) (T1), 20 min of bottom time (T2), and at 5 m (1.5 ATA) (T3). RESULTS: CFFF results showed a slight increase in alertness and arousal during the deep dive regardless of the gas mixture breathed. The percent change in CFFF values at T1 and T2 differed among the three groups being lower in the air group than in the other groups. All CFFF values returned to basal values 5 min before the final ascent at 5 m (T3), but the Trimix measurements were still slightly better than those at T0. CONCLUSIONS: Our results highlight that nitrogen and oxygen alone and in combination can produce neuronal excitability or depression in a dose-related response.

A proof-of-concept trial of HELIOX with different fractions of helium in a human study modeling upper airway obstruction.

BACKGROUND: Helium in oxygen (HELIOX) can relieve airway obstruction and lower the work of breathing because it increases the threshold at which turbulent gas flow is induced. Less turbulent and more laminar flow lowers the work of breathing. According to guidelines, the fraction of Helium in HELIOX should be maximized (e.g. to 79%). Here, we investigate whether HELIOX with less than 60% of Helium is able to relieve the sensation of dyspnea in healthy volunteers. METHODS: 44 volunteers underwent resistive loading breathing different gases (medical air and HELIOX with a fraction of 25%, 50% or 75% helium in oxygen) in a double-blinded crossover design. Subjects rated their degree of dyspnea (primary outcome parameter) and the variability of noninvasively measured systolic blood pressure was assessed. RESULTS: Dyspnea was significantly reduced by HELIOX-containing mixtures with a fraction of helium of 25% or more. Similarly, blood pressure variability was reduced significantly even with helium 25% during respiratory loading with the higher load, whereas with the smaller load an effect could only be obtained with the highest helium fraction of 75%. CONCLUSION: In this clinical trial, HELIOX with less than 60% of helium in oxygen decreased the sensation of dyspnea and blood pressure variability, a surrogate parameter for airway obstruction. Therefore, higher oxygen fractions might be applied without losing the helium-related benefits for the treatment of upper airway obstruction. TRIAL REGISTRATION: Registration with clinical trials (NCT00788788) and EMA (EudraCT number: 2006-005289-37).

Detrimental Effects of Helium Ion Irradiation on Cognitive Performance and Cortical Levels of MAP-2 in B6D2F1 Mice.

The space radiation environment includes helium (4He) ions that may impact brain function. As little is known about the effects of exposures to 4He ions on the brain, we assessed the behavioral and cognitive performance of C57BL/6J × DBA2/J F1 (B6D2F1) mice three months following irradiation with 4He ions (250 MeV/n; linear energy transfer (LET) = 1.6 keV/μm; 0, 21, 42 or 168 cGy). Sham-irradiated mice and mice irradiated with 21 or 168 cGy showed novel object recognition, but mice irradiated with 42 cGy did not. In the passive avoidance test, mice received a slight foot shock in a dark compartment, and latency to re-enter that compartment was assessed 24 h later. Sham-irradiated mice and mice irradiated with 21 or 42 cGy showed a higher latency on Day 2 than Day 1, but the latency to enter the dark compartment in mice irradiated with 168 cGy was comparable on both days. 4He ion irradiation, at 42 and 168 cGy, reduced the levels of the dendritic marker microtubule-associated protein-2 (MAP-2) in the cortex. There was an effect of radiation on apolipoprotein E (apoE) levels in the hippocampus and cortex, with higher apoE levels in mice irradiated at 42 cGy than 168 cGy and a trend towards higher apoE levels in mice irradiated at 21 than 168 cGy. In addition, in the hippocampus, there was a trend towards a negative correlation between MAP-2 and apoE levels. While reduced levels of MAP-2 in the cortex might have contributed to the altered performance in the passive avoidance test, it does not seem sufficient to do so. The higher hippocampal and cortical apoE levels in mice irradiated at 42 than 168 cGy might have served as a compensatory protective response preserving their passive avoidance memory. Thus, there were no alterations in behavioral performance in the open filed or depressive-like behavior in the forced swim test, while cognitive impairments were seen in the object recognition and passive avoidance tests, but not in the contextual or cued fear conditioning tests. Taken together, the results indicate that some aspects of cognitive performance are altered in male mice exposed to 4He ions, but that the response is task-dependent. Furthermore, the sensitive doses can vary within each task in a non-linear fashion. This highlights the importance of assessing the cognitive and behavioral effects of charged particle exposure with a variety of assays and at multiple doses, given the possibility that lower doses may be more damaging due to the absence of induced compensatory mechanisms at higher doses.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery.

BACKGROUND: This is an update of the review published in 2013.Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. People with high anaesthetic risk are more likely to experience cardiopulmonary complications and adverse events, for example hypercapnia and acidosis, which has to be avoided by hyperventilation. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum. OBJECTIVES: To assess the safety, benefits, and harms of different gases (i.e. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic general abdominal or gynaecological pelvic surgery. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 9), Ovid MEDLINE (1950 to September 2016), Ovid Embase (1974 to September 2016), Science Citation Index Expanded (1970 to September 2016), Chinese Biomedical Literature Database (CBM) (1978 to September 2016), ClinicalTrials.gov (September 2016), and World Health Organization International Clinical Trials Registry Platform (September 2016). SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia. DATA COLLECTION AND ANALYSIS: Two review authors identified the trials for inclusion, collected the data, and assessed the risk of bias independently. We performed the meta-analyses using Review Manager 5. We calculated risk ratio (RR) for dichotomous outcomes (or Peto odds ratio for very rare outcomes), and mean difference (MD) or standardised mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI). We used GRADE to rate the quality of evidence, MAIN RESULTS: We included nine RCTs, randomising 519 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (three trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. Three trials randomised participants to nitrous oxide pneumoperitoneum (100 participants) or carbon dioxide pneumoperitoneum (96 participants). None of the trials was at low risk of bias. There was insufficient evidence to determine the effects of nitrous oxide and carbon dioxide on cardiopulmonary complications (RR 2.00, 95% CI 0.38 to 10.43; two studies; 140 participants; very low quality of evidence), or surgical morbidity (RR 1.01, 95% CI 0.18 to 5.71; two studies; 143 participants; very low quality of evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (three studies; 196 participants; very low quality of evidence). We could not combine data from two trials (140 participants) which individually showed lower pain scores (a difference of about one visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain) with nitrous oxide pneumoperitoneum at various time points on the first postoperative day, and this was rated asvery low quality .Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. There was insufficient evidence to determine the effects of helium or carbon dioxide on cardiopulmonary complications (RR 1.46, 95% CI 0.35 to 6.12; three studies; 128 participants; very low quality of evidence) or pain scores (visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain; MD 0.49 cm, 95% CI -0.28 to 1.26; two studies; 108 participants; very low quality of evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (three studies; 128 participants; very low quality of evidence).One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at unclear risk of bias. There were no cardiopulmonary complications or serious adverse events observed related to either room air or carbon dioxide pneumoperitoneum (both outcomes very low quality of evidence). The evidence of lower hospital costs and reduced pain during the first postoperative day with room air pneumoperitoneum compared with carbon dioxide pneumoperitoneum (a difference of about one visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain, was rated as very low quality of evidence. AUTHORS' CONCLUSIONS: The quality of the current evidence is very low. The effects of nitrous oxide and helium pneumoperitoneum compared with carbon dioxide pneumoperitoneum are uncertain. Evidence from one trial of small sample size suggests that room air pneumoperitoneum may decrease hospital costs in people undergoing laparoscopic abdominal surgery. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established.Further trials on this topic are needed, and should compare various gases (i.e. nitrous oxide, helium, argon, nitrogen, and room air) with carbon dioxide under standard pressure pneumoperitoneum with cold gas insufflation for people with high anaesthetic risk. Future trials should include outcomes such as complications, serious adverse events, quality of life, and pain.

The BIANCA model/code of radiation-induced cell death: application to human cells exposed to different radiation types.

This paper presents a biophysical model of radiation-induced cell death, implemented as a Monte Carlo code called BIophysical ANalysis of Cell death and chromosome Aberrations (BIANCA), based on the assumption that some chromosome aberrations (dicentrics, rings, and large deletions, called ''lethal aberrations'') lead to clonogenic inactivation. In turn, chromosome aberrations are assumed to derive from clustered, and thus severe, DNA lesions (called ''cluster lesions,'' or CL) interacting at the micrometer scale; the CL yield and the threshold distance governing CL interaction are the only model parameters. After a pilot study on V79 hamster cells exposed to protons and carbon ions, in the present work the model was extended and applied to AG1522 human cells exposed to photons, He ions, and heavier ions including carbon and neon. The agreement with experimental survival data taken from the literature supported the assumptions. In particular, the inactivation of AG1522 cells was explained by lethal aberrations not only for X-rays, as already reported by others, but also for the aforementioned radiation types. Furthermore, the results are consistent with the hypothesis that the critical initial lesions leading to cell death are DNA cluster lesions having yields in the order of *2 CL Gy-1 cell-1 at low LET and*20 CL Gy-1 cell-1 at high LET, and that the processing of these lesions is modulated by proximity effects at the micrometer scale related to interphase chromatin organization. The model was then applied to calculate the fraction of inactivated cells, as well as the yields of lethal aberrations and cluster lesions, as a function of LET; the results showed a maximum around 130 keV/lm, and such maximum was much higher for cluster lesions and lethal aberrations than for cell inactivation.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery.

BACKGROUND: Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Many other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum. OBJECTIVES: To assess the safety, benefits, and harms of different gases for establishing pneumoperitoneum in patients undergoing laparoscopic abdominal surgery. SEARCH METHODS: We searched The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and Chinese Biomedical Literature Database (CBM) until September 2012. SELECTION CRITERIA: We only included randomized controlled trials comparing different gases for establishing pneumoperitoneum in patients undergoing laparoscopic abdominal surgery under general anaesthesia. DATA COLLECTION AND ANALYSIS: Two review authors identified the trials for inclusion, collected the data, and assessed the risk of bias independently. We performed the meta-analyses using Review Manager 5. We calculated the risk ratio (RR) for dichotomous outcomes and the mean difference (MD) or standardized mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI). MAIN RESULTS: Carbon dioxide pneumoperitoneum versus nitrous oxide pneumoperitoneum Three trials randomized 196 participants (the majority with low anaesthetic risk) to carbon dioxide pneumoperitoneum (n =96) or nitrous oxide pneumoperitoneum (n =100). All of the trials were of high risk of bias. Two trials (n=143) showed lower pain scores in nitrous oxide pneumoperitoneum at various time points on the first post-operative day. One trial (n=53) showed no difference in the pain scores between the groups. There were no significant differences in cardiopulmonary complications, surgical morbidity, or cardiopulmonary changes between the groups. There were no serious adverse events related to either carbon dioxide or nitrous oxide pneumoperitoneum. Carbon dioxide pneumoperitoneum versus helium pneumoperitoneum Four trials randomized 144 participants (the majority with low anaesthetic risk) to carbon dioxide pneumoperitoneum (n =75) or helium pneumoperitoneum (n =69). All of the trials were of high risk of bias. Fewer cardiopulmonary changes were observed with helium pneumoperitoneum than carbon dioxide pneumoperitoneum. There were no significant differences in cardiopulmonary complications, surgical morbidity, or pain scores. There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum. Carbon dioxide pneumoperitoneum versus any other gas pneumoperitoneum There were no randomized controlled trials comparing carbon dioxide pneumoperitoneum to any other gas pneumoperitoneum. AUTHORS' CONCLUSIONS: 1. Nitrous oxide pneumoperitoneum during laparoscopic abdominal surgery appears to decrease post-operative pain in patients with low anaesthetic risk.2. Helium pneumoperitoneum decreases the cardiopulmonary changes associated with laparoscopic abdominal surgery. However, this did not translate into any clinical benefit over carbon dioxide pneumoperitoneum in patients with low anaesthetic risk.3. The safety of nitrous oxide and helium pneumoperitoneum has yet to be established. More randomized controlled trials on this topic are needed. Future trials should include more patients with high anaesthetic risk. Furthermore, such trials need to use adequate methods to reduce the risk of bias.

Neurological oxygen toxicity.

SCUBA diving has several risks associated with it from breathing air under pressure--nitrogen narcosis, barotrauma and decompression sickness (the bends). Trimix SCUBA diving involves regulating mixtures of nitrogen, oxygen and helium in an attempt to overcome the risks of narcosis and decompression sickness during deep dives, but introduces other potential hazards such as hypoxia and oxygen toxicity convulsions. This study reports on a seizure during the ascent phase, its potential causes and management and discusses the hazards posed to the diver and his rescuer by an emergency ascent to the surface.

Human mesenchymal stromal cells maintain their stem cell traits after high-LET particle irradiation - Potential implications for particle radiotherapy and manned space missions.

The influence of high-linear energy transfer (LET) particle radiation on the functionalities of mesenchymal stromal cells (MSCs) is largely unknown. Here, we analyzed the effects of proton (1H), helium (4He), carbon (12C) and oxygen (16O) ions on human bone marrow-MSCs. Cell cycle distribution and apoptosis induction were examined by flow cytometry, and DNA damage was quantified using γH2AX immunofluorescence and Western blots. Relative biological effectiveness values of MSCs amounted to 1.0-1.1 for 1H, 1.7-2.3 for 4He, 2.9-3.4 for 12C and 2.6-3.3 for 16O. Particle radiation did not alter the MSCs' characteristic surface marker pattern, and MSCs maintained their multi-lineage differentiation capabilities. Apoptosis rates ranged low for all radiation modalities. At 24 h after irradiation, particle radiation-induced ATM and CHK2 phosphorylation as well as γH2AX foci numbers returned to baseline levels. The resistance of human MSCs to high-LET irradiation suggests that MSCs remain functional after exposure to moderate doses of particle radiation as seen in normal tissues after particle radiotherapy or during manned space flights. In the future, in vivo models focusing on long-term consequences of particle irradiation on the bone marrow niche and MSCs are needed.

Suicide by asphyxiation due to helium inhalation.

Suicide by asphyxiation using helium is the most widely-promoted method of "self-deliverance" by right-to-die advocates. However, little is known about persons committing such suicides or the circumstances and manner in which they are completed. Prior reports of suicides by asphyxiation involving helium were reviewed and deaths determined by the North Carolina Office of the Chief Medical Examiner to be helium-associated asphyxial suicides occurring between January 1, 2000 and December 31, 2008 were included in a new case series examined in this article. The 10 asphyxial suicides involving helium identified in North Carolina tended to occur almost exclusively in non-Hispanic, white men who were relatively young (M age = 41.1 T 11.6). In 6 of 10 cases, decedents suffered from significant psychiatric dysfunction; in 3 of these 6 cases, psychiatric disorders were present comorbidly with substance abuse. In none of these cases were decedents suffering from terminal illness. Most persons committing suicide with helium were free of terminal illness but suffered from psychiatric and/or substance use disorders.

Cold atmospheric pressure He-plasma jet and plasma ball interactions with the Venus flytrap: Electrophysiology and side effects.

Cold atmospheric pressure radio frequency plasma (CAPP) can play an important role in agriculture, medicine, biophysical and bioelectrochemical applications, disinfection and sterilization, synthesis of different compounds, nitrogen fixation, and treatment of surfaces. Here we found that reactive oxygen and nitrogen species, UV-Vis photons, and high-frequency strong electromagnetic fields with an amplitude of a few kV produced by a cold plasma jet can interact with bio-tissue and damage it if the plasma treatment is long enough. The electrophysiological effects of CAPP treatment of bio-tissue and electrical signals transmission were measured in the Venus flytrap. The plasma ball does not produce any visible side effects on the Venus flytrap, but induces electrical signals in bio-tissue with very high amplitude. Plasma (Kirlian) photography shows the existence of a blue aura around the plasma ball due to a corona discharge. Understanding the mechanisms of interactions between CAPP and bio-tissue and preventing side effects can contribute to the application of plasma technology in medicine and agriculture. The use of cold plasma in medicine and agriculture should be monitored for side effects from strong high-frequency electro-magnetic fields, UV photons, and reactive oxygen and nitrogen species to protect against undesirable consequences.

Helium/oxygen-driven albuterol nebulization in the management of children with status asthmaticus: a randomized, placebo-controlled trial.

OBJECTIVES: We investigated the effect of heliox-powered albuterol therapy on hospital length of stay and clinical status in children with moderate to severe status asthmaticus. DESIGN: Prospective, randomized, placebo-controlled trial. SETTING: Twenty-five-bed pediatric intensive care unit at an academic children's medical center. PATIENTS: Forty-two children (2-21 yrs of age) with moderate to severe status asthmaticus. INTERVENTIONS: Patients were randomized to receive either heliox-powered nebulized albuterol or air/oxygen-powered nebulized albuterol (placebo) until they were transitioned to albuterol delivered by a metered dose inhaler. MEASUREMENTS AND MAIN RESULTS: Clinical asthma scores were recorded on enrollment and every 4 hrs thereafter. Patients in the heliox group (n = 22) and the control group (n = 20) had similar ages (mean +/- sem: 88 +/- 9.9 vs. 98 +/- 11.1 months, respectively; p = .51), time to study enrollment (618 +/- 70.4 vs. 597 +/- 84.1 mins, respectively; p = .72), and clinical asthma scores at study entry (5.9 +/- 0.2 vs. 5.7 +/- 0.3, respectively; p = .72). There were no significant differences between groups in time to eligibility to hospital discharge (66.2 +/- 8.7 vs. 63.4 +/- 8.6 hrs, respectively; p = .61), time to clinical asthma score <3 (22 +/- 2.8 vs. 21.2 +/- 5.3 hrs, respectively; p = .27), or time to eligibility for intensive care unit discharge (34.4 +/- 6.8 vs. 33.3 +/- 8.2 hrs, respectively; p = .64). There were no significant differences in adverse events between groups. CONCLUSIONS: Despite the previously demonstrated effects of heliox on improved aerosol particle delivery into the distal airways, heliox-powered nebulized albuterol therapy for children admitted to the hospital with moderate to severe status asthmaticus does not shorten hospital length of stay or hasten rates of clinical improvement when compared with air/oxygen-powered nebulized albuterol.

Pneumomediastinum after inhalation of helium gas from party balloons.

A previously healthy 16-year-old boy presented to the Emergency Department with a 2-day history of hoarseness, sore throat, and chest tightness. The physical examination was significant for diffuse neck and chest subcutaneous emphysema. A computed tomography (CT) scan of the neck and chest revealed pneumomediastinum after a plain chest X-ray study failed to uncover this finding. The patient reported that 5 days before presentation he forcefully inhaled helium gas directly from multiple party balloons in an attempt to alter his voice. The patient fully recovered over the next 2 days. Spontaneous pneumomediastinum developed in this patient with no underlying lung disease, presumably from air leakage secondary to the excessive elevation of intra-thoracic pressure due to repetitive inhalation of helium gas. Spontaneous pneumomediastinum remains largely underdiagnosed clinically, especially in young, healthy patients.

Observation of two suicides by helium inhalation in a prefilled environment.

In recent years information about suicide with helium has spread rapidly on the Internet, in print, and even on video. Increased awareness of this suicide method means that instead of turning to a physician for aid in dying, some people will terminate their lives with this nonpharmaceutical method. Although there are many case reports of hypoxic suicide by helium inhalation, little is known about the pathophysiology of this type of death. Pathologists should know what hypoxic suicide looks like. Carefully planned, autonomous suicides present possibilities for passive, naturalistic observation of the phenomenon. This article describes a method for direct observation of suicide and reports on 2 hypoxic suicides from inhalation of helium inside a prefilled environment.

Helium suicide - A suffocation or a barotrauma?

Helium is a chemically inert gas present in atmospheric air that is used in various branches of industry and in medicine. In the case of its improper use, various complications may occur, affecting mainly the respiratory tract and, in extreme cases, even result in death. Helium has also been used for committing suicide. Helium suicide is a method that does not leave characteristic macro- and microscopic post-mortem changes. A large amount of information on how to commit suicide with the use of helium can be found on the internet, which contributes to the popularization of this method in the world. In the case of incompetent use of the equipment theoretically dedicated to such suicide, death may occur not because of the suffocation, which is the most common mechanism in such cases, but because of a pressure injury of the respiratory tract, resulting in rapid damage to the alveoli in the rupture mechanism, causing massive bleeding. Helium dissipates quickly in the ambient air, and usually, its presence cannot be detected either in the blood or in the tissues. Thus, even if the material for toxicological tests is handled properly, detection of the presence of helium in a relatively short period of time after death is usually impossible or very difficult. If death due to inert gas inhalation is suspected during an autopsy, samples of biological material can be collected to be tested later by gas chromatography combined with mass spectrometry (GC-MS), but the results of the investigations are usually not helpful from the point of view of a forensic pathologist.

Effects of exposure to 12C and 4He particles on cognitive performance of intact and ovariectomized female rats.

Exposure to the types of radiation encountered outside the magnetic field of the earth can disrupt cognitive performance. Exploratory class missions to other planets will include both male and female astronauts. Because estrogen can function as a neuroprotectant, it is possible that female astronauts may be less affected by exposure to space radiation than male astronauts. To evaluate the effectiveness of estrogen to protect against the disruption of cognitive performance by exposure to space radiation intact and ovariectomized female rats with estradiol or vehicle implants were tested on novel object performance and operant responding on an ascending fixed-ratio reinforcement schedule following exposure to 12C (290 MeV/n) or 4He (300 MeV/n) particles. The results indicated that exposure to carbon or helium particles did not disrupt cognitive performance in the intact rats. Estradiol implants in the ovariectomized subjects exacerbated the disruptive effects of space radiation on operant performance. Although estrogen does not appear to function as a neuroprotectant following exposure to space radiation, the present data suggest that intact females may be less responsive to the deleterious effects of exposure to space radiation on cognitive performance, possibly due to the effects of estrogen on cognitive performance.

Hyperpolarized 3He MR imaging: physiologic monitoring observations and safety considerations in 100 consecutive subjects.

PURPOSE: To evaluate the safety of hyperpolarized helium 3 ((3)He) magnetic resonance (MR) imaging. MATERIALS AND METHODS: Local institutional review board approval and informed consent were obtained. Physiologic monitoring data were obtained before, during, and after hyperpolarized (3)He MR imaging in 100 consecutive subjects (57 men, 43 women; mean age, 52 years +/- 14 [standard deviation]). The subjects inhaled 1-3 L of a gas mixture containing 300-500 mL (3)He and 0-2700 mL N(2) and held their breath for up to 15 seconds during MR imaging. Heart rate and rhythm and oxygen saturation of hemoglobin as measured by pulse oximetry (Spo(2)) were monitored continuously throughout each study. The effects of (3)He MR imaging on vital signs and Spo(2) and the relationship between pulmonary function, number of doses, and clinical classification (healthy volunteers, patients with asthma, heavy smokers, patients undergoing lung volume reduction surgery for severe emphysema, and patients with lung cancer) and the lowest observed Spo(2) were assessed. Any subjective symptoms were noted. RESULTS: Except for a small postimaging decrease in mean heart rate (from 78 beats per minute +/- 13 to 73 beats per minute +/- 11, P < .001), there was no effect on vital signs. A mean transient decrease in Spo(2) of 4% +/- 3 was observed during the first minute after gas inhalation (P < .001) in 77 subjects who inhaled a dose of 1 L for 10 seconds or less, reaching a nadir of less than 90% at least once in 20 subjects and of less than 85% in four subjects. There was no correlation between the lowest Spo(2) and pulmonary function parameters other than baseline Spo(2) (r = 0.36, P = .001). The lowest mean Spo(2) varied by 1% between the first and second and second and third doses (P < .001) and was unrelated to clinical classification (P = .40). Minor subjective symptoms were noted by 10 subjects. No serious adverse events occurred. CONCLUSION: Hyperpolarized (3)He MR imaging can be safely performed in healthy subjects, heavy smokers, and those with severe obstructive airflow limitation, although unpredictable transient desaturation suggests that potential subjects should be carefully screened for comorbidities.