Skin Lesions in Swine with Decompression Sickness: Clinical Appearance and Pathogenesis.
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SUBMITTER: Qing L
PROVIDER: S-EPMC5524778 | biostudies-other | 2017
REPOSITORIES: biostudies-other
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Project description:Massive bubble formation after diving can lead to decompression sickness (DCS). During dives with hydrogen as a diluent for oxygen, decreasing the body's H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. So we set out to investigate if colonic fermentation leading to endogenous hydrogen production promotes DCS in fasting rats. Four hours before an experimental dive, 93 fasting rats were force-fed, half of them with mannitol and the other half with water. Exhaled hydrogen was measured before and after force-feeding. Following the hyperbaric exposure, we looked for signs of DCS. A higher incidence of DCS was found in rats force-fed with mannitol than in those force-fed with water (80%, [95%CI 56, 94] versus 40%, [95%CI 19, 64], p < 0.01). In rats force-fed with mannitol, metronidazole pretreatment reduced the incidence of DCS (33%, [95%CI 15, 57], p = 0.005) at the same time as it inhibited colonic fermentation (14 ± 35 ppm versus 118 ± 90 ppm, p = 0.0001). Pre-diveingestion of mannitol increased the incidence of DCS in fasting rats when colonic fermentation peaked during the decompression phase. More generally, colonic fermentation in rats on a normal diet could promote DCS through endogenous hydrogen production.
| S-EPMC4745042 | biostudies-literature
Project description:IntroductionMost cases of decompression sickness (DCS) occur soon after surfacing, with 98% within 24 hours. Recompression using hyperbaric chamber should be administrated as soon as feasible in order to decrease bubble size and avoid further tissue injury. Unfortunately, there may be a significant time delay from surfacing to recompression. The time beyond which hyperbaric treatment is non effective is unclear. The aims of the study were first to evaluate the effect of delayed hyperbaric treatment, initiated more than 48 h after surfacing for DCS and second, to evaluate the different treatment protocols.MethodsFrom January 2000 to February 2014, 76 divers had delayed hyperbaric treatment (≥48 h) for DCS in the Sagol center for Hyperbaric medicine and Research, Assaf-Harofeh Medical Center, Israel. Data were collected from their medical records and compared to data of 128 patients treated earlier than 48 h after surfacing at the same hyperbaric institute.ResultsThere was no significant difference, as to any of the baseline characteristics, between the delayed and early treatment groups. With respect to treatment results, at the delayed treatment divers, complete recovery was achieved in 76% of the divers, partial recovery in 17.1% and no improvement in 6.6%. Similar results were achieved when treatment started early, where 78% of the divers had complete recovery, 15.6% partial recovery and 6.2% no recovery. Delayed hyperbaric treatment using US Navy Table 6 protocol trended toward a better clinical outcome yet not statistically significant (OR=2.786, CI95%[0.896-8.66], p=0.07) compared to standard hyperbaric oxygen therapy of 90 minutes at 2 ATA, irrespective of the symptoms severity at presentation.ConclusionsLate recompression for DCS, 48 hours or more after surfacing, has clinical value and when applied can achieve complete recovery in 76% of the divers. It seems that the preferred hyperbaric treatment protocol should be based on US Navy Table 6.
| S-EPMC4408070 | biostudies-literature
Project description:A 53-year-old man, who performed a 44-minute dive to a depth of 21 meters, felt severe abdominal pain with dyspnea after surfacing. An ultrasound study showed a marked snowstorm pattern in the portal vein of the liver and right ventricle, and whole body computed tomography revealed multiple gas bubbles in the right ventricle, inferior vena cava, portal, mesenteric and femoral vein. He was thus diagnosed to have decompression sickness and was therefore transported to another hospital to undergo hyperbaric oxygen therapy. Patients who present with abdominal symptoms after diving should be immediately evaluated by ultrasound and computed tomography.
| S-EPMC7809215 | biostudies-literature
Project description:Decompression sickness (DCS) is a potentially fatal condition usually observed after scuba diving. It involves bubble formation in blood and tissues from dissolved inert gas (usually nitrogen or helium), secondary to decreases in ambient pressure (decompression).To the best of our knowledge, no study has evaluated a DCS-induced transcriptomic signature in humans. In this study, we aim to explore the evolution of leukocyte gene expression in human subjects with DCS compared to closely matched divers after uneventful diving using a hypothesis-free RNA sequencing approach .Recruitment of DCS cases (n = 7) and controls (n = 6) was carried out using specific criteria. For both DCS cases and controls, whole blood was sampled at two time points, T1 - within 8 hours of surfacing from diving and T2 - at 40-44 hours after surfacing. Prior to sampling at T2, subjects were fasted for 10 hours. Specific exclusion criteria included a) age < 18 years b) self-reported consumption of alcohol and/or strenuous physical activity before T2 c) symptoms suggestive of delayed DCS presentation in controls at T2 d) acute life-threatening clinical complications or death within 72 hours of surfacing. All cases received emergency HBO as per United States Navy Treatment Table Six between T1 and T2.For RNA isolation, 2.5mL of whole blood was collected in a PAXgene® Blood RNA Tube (PreAnalytiX, Qiagen/BD) from DCS cases and controls at both T1 and T2. The quality of RNA was evaluated by RNA Integrity Number (RIN) determination using the RNA6000 Nano protocol on an Agilent 2100 Bioanalyzer system (Agilent, USA). The RIN values for samples undergoing transcriptome analysis ranged from 7.8 to 9.3. Depletion of alpha and beta globin mRNA was carried out using the GLOBINclear™ kit (ThermoFisher Scientific). To minimize batch effects, all samples were processed simultaneously by the same investigator. RNA samples were submitted for library generation and sequencing by the Beijing Genomics Institute (BGI-Shenzhen). Briefly, poly(A) mRNA was enriched using poly(T) oligo-attached magnetic beads, followed by fragmentation. First strand cDNA synthesis was carried out using random hexamer N6 primers and reverse transcriptase. Following adaptor ligation to cDNA fragments, PCR amplification and purification, single stranded DNA circles were generated in a final library. DNA nanoballs (DNBs) were subsequently generated by rolling circle replication, which underwent paired end sequencing (100bp) on the BGI DNBseq platform.
2021-05-23 | E-MTAB-10388 | biostudies-arrayexpress
Project description:IntroductionLimited evidence suggests that shorter recompression schedules may be as efficacious as the US Navy Treatment Table 6 (USN TT6) for treatment of milder presentations of decompression sickness (DCS). This study aimed to determine if divers with mild DCS could be effectively treated with a shorter chamber treatment table.MethodsAll patients presenting to the Fremantle Hospital Hyperbaric Medicine Unit with suspected DCS were assessed for inclusion. Participants with mild DCS were randomly allocated to receive recompression in a monoplace chamber via either a modified USN TT6 (TT6m) or a shorter, custom treatment table (FH01). The primary outcome was the number of treatments required until resolution or no further improvement (plateau).ResultsForty-one DCS cases were included, 21 TT6m and 20 FH01. Two patients allocated to FH01 were moved to TT6m mid-treatment due to failure to significantly improve (as per protocol), and two TT6m required extensions. The median total number of treatments till symptom resolution was 1 (IQR 1-1) for FH01 and 2 (IQR 1-2) for TT6m (P = 0.01). More patients in the FH01 arm (17/20, 85%) showed complete symptom resolution after the initial treatment, versus 8/21 (38%) for TT6m (P = 0.003). Both FH01 and TT6m had similar overall outcomes, with 19/20 and 20/21 respectively asymptomatic at the completion of their final treatment (P = 0.97). In all cases where two-week follow-up contact was made, (n = 14 FH01 and n = 12 TT6m), patients reported maintaining full symptom resolution.ConclusionsThe median total number of treatments till symptom resolution was meaningfully fewer with FH01 and the shorter treatment more frequently resulted in complete symptom resolution after the initial treatment. There were similar patient outcomes at treatment completion, and at follow-up. We conclude that FH01 appears superior to TT6m for the treatment of mild decompression sickness.
| S-EPMC9522606 | biostudies-literature
Project description:Massive bubble formation after diving can lead to decompression sickness (DCS), which can result in neurological disorders. We demonstrated that hydrogen production from intestinal fermentation could exacerbate DCS in rats fed with a standard diet. The aim of this study is to identify a fecal metabolomic signature that may result from the effects of a provocative hyperbaric exposure. The fecal metabolome was studied in two groups of rats previously fed with maize or soy in order to account for diet effects. 64 animals, weighing 379.0_20.2 g on the day of the dive, were exposed to the hyperbaric protocol. The rats were separated into two groups: 32 fed with maize (Div MAIZE) and 32 fed with soy (Div SOY). Gut fermentation before the dive was estimated by measuring exhaled hydrogen. Following hyperbaric exposure, we assessed for signs of DCS. Blood was analyzed to assay inflammatory cytokines. Conventional and ChemRICH approaches helped the metabolomic interpretation of the cecal content. The effect of the diet is very marked at the metabolomic level, a little less in the blood tests, without this appearing strictly in the clinic status. Nevertheless, 37 of the 184 metabolites analyzed are linked to clinical status. 35 over-expressed compounds let suggest less intestinal absorption, possibly accompanied by an alteration of the gut microbial community, in DCS. The decrease in another metabolite suggests hepatic impairment. This spectral difference of the ceca metabolomes deserves to be studied in order to check if it corresponds to functional microbial particularities.
| S-EPMC7524739 | biostudies-literature
Project description:Massive bubble formation after diving can lead to decompression sickness (DCS). Gut fermentation at the time of a dive exacerbates DCS due to endogenous hydrogen production. We sought to investigate whether medium-term stimulation of fermentation as a result of polyethylene glycol (PEG)-induced acceleration of bowel transit before diving exacerbates DCS in rats. Seven days before an experimental dry dive, 60 rats were randomly divided in two groups: an experimental group treated with PEG (n = 30) and an untreated control group (n = 30). Exhaled hydrogen was measured before the dive. Following hyperbaric exposure, we assessed for signs of DCS. After anaesthetisation, arterial blood was drawn to assay inflammatory cytokines and markers of oxidative stress. PEG led to a significant increase in exhaled H2 (35 ppm [10-73] compared with control 7 ppm [2-15]; p = 0.001). The probability of death was reduced in PEG-treated rats (PEG: 17% [95% CI 4-41] vs control: 50% [95% CI 26-74]; p = 0.034). In addition, inflammatory markers were reduced, and the antioxidant activity of glutathione peroxidase was significantly increased (529.2 U.l-1 [485.4-569.0] versus 366.4 U.l-1 [317.6-414.8]; p = 0.004). Thus, gut fermentation might have a positive effect on DCS. The antioxidant and neuroprotective properties of the fermentation by-products H2 and butyrate may explain these results.
| S-EPMC6031626 | biostudies-literature
Project description:Automated machine learning approaches to skin lesion diagnosis from images are approaching dermatologist-level performance. However, current machine learning approaches that suggest management decisions rely on predicting the underlying skin condition to infer a management decision without considering the variability of management decisions that may exist within a single condition. We present the first work to explore image-based prediction of clinical management decisions directly without explicitly predicting the diagnosis. In particular, we use clinical and dermoscopic images of skin lesions along with patient metadata from the Interactive Atlas of Dermoscopy dataset (1011 cases; 20 disease labels; 3 management decisions) and demonstrate that predicting management labels directly is more accurate than predicting the diagnosis and then inferring the management decision ([Formula: see text] and [Formula: see text] improvement in overall accuracy and AUROC respectively), statistically significant at [Formula: see text]. Directly predicting management decisions also considerably reduces the over-excision rate as compared to management decisions inferred from diagnosis predictions (24.56% fewer cases wrongly predicted to be excised). Furthermore, we show that training a model to also simultaneously predict the seven-point criteria and the diagnosis of skin lesions yields an even higher accuracy (improvements of [Formula: see text] and [Formula: see text] in overall accuracy and AUROC respectively) of management predictions. Finally, we demonstrate our model's generalizability by evaluating on the publicly available MClass-D dataset and show that our model agrees with the clinical management recommendations of 157 dermatologists as much as they agree amongst each other.
| S-EPMC8032721 | biostudies-literature
Project description:Decompression sickness (DCS) develops due to inert gas bubble formation in bodily tissues and in the circulation, leading to a wide range of potentially serious clinical manifestations. Its pathophysiology remains incompletely understood. In this study, we aim to explore changes in the human leukocyte transcriptome in divers with DCS compared to closely matched unaffected controls after uneventful diving. Cases (n = 7) were divers developing the typical cutis marmorata rash after diving with a confirmed clinical diagnosis of DCS. Controls (n = 6) were healthy divers who surfaced from a ≥25 msw dive without decompression violation or evidence of DCS. Blood was sampled at two separate time points-within 8 h of dive completion and 40-44 h later. Transcriptome analysis by RNA-Sequencing followed by bioinformatic analysis was carried out to identify differentially expressed genes and relate their function to biological pathways. In DCS cases, we identified enrichment of transcripts involved in acute inflammation, activation of innate immunity and free radical scavenging pathways, with specific upregulation of transcripts related to neutrophil function and degranulation. DCS-induced transcriptomic events were reversed at the second time point following exposure to hyperbaric oxygen. The observed changes are consistent with findings from animal models of DCS and highlight a continuum between the responses elicited by uneventful diving and diving complicated by DCS. This study sheds light on the inflammatory pathophysiology of DCS and the associated immune response. Such data may potentially be valuable in the search for novel treatments targeting this disease.
| S-EPMC8222921 | biostudies-literature
Project description:Malignant melanoma and nonmelanoma skin cancers (NMSC), which include basal cell carcinoma and squamous cell carcinoma, account for 40% of all neoplasms in white patients, making these cancers the most common malignancy in the United States. Given the large number of NMSC cases in white patients, there is a correspondingly large body of literature addressing various aspects of epidemiology, pathogenesis, and treatment. The incidence of both malignant melanoma and NMSC is well established and remains significantly lower in patients with skin of color (SoC) when compared with white patients. Although there is a lower incidence of skin cancer in SoC, there is often a poorer prognosis among this group. There is even more limited data focusing on women of color, making an accurate determination of incidence and mortality difficult. This gender disparity causes decreased skin cancer awareness and index of suspicion among patients and providers, hindering appropriate evaluation and care. Therefore, there is a need for an increased understanding of skin cancer in women of color. In the traditional sense, SoC refers to people of African, Asian, Native American, Middle Eastern, and Hispanic backgrounds. Patients in these ethnic groups have richly pigmented skin that is usually categorized as Fitzpatrick types III through VI and thus have notable differences in skin disease and presentation compared with fair-skinned individuals. We present this review of skin cancer in women of color to give a reasonably comprehensive representation of the literature to advance our understanding and knowledge in this unique population.
| S-EPMC8072498 | biostudies-literature