Under pressure: Effects of instrumentation methods on fur seal pelt function

Tracking marine mammals with electronic devices enables researchers to better understand animal movements and at-sea behavior. For pinnipeds, instruments are typically glued to the animal's hair, either directly to the pelage or via a fabric patch. These instruments are retrieved by cutting the pelage or cutting through the patch. The impact of these modifications to the pelage is presumed to be minimal and short-lived, but this has never been explicitly investigated. This study examined effects of instrument attachment on northern fur seal pelts. To assess thermal consequences of instrumentation, we determined thermal resistance of pelts in water for instruments glued directly to the pelage or with a neoprene base. For each attachment method, we measured the pelt unmodified, with instrument attached, and with instrument removed. Using a hyperbaric chamber, we measured the extent to which water could penetrate the pelt's air layer during diving. Removing the tag by cutting the pelage reduced thermal function of the pelt in water and allowed more air to escape under pressure. In contrast, a neoprene patch better maintained the insulation in water and reduced air loss under pressure. Our results suggest the use of neoprene may reduce negative consequences of instrumentation in fur seals.     

Scuba diving enhances endogenous antioxidant defenses in lymphocytes and neutrophils

The aim was to study the effects of a scuba diving session on the lymphocyte antioxidant system, NO synthesis, the capability to produce reactive oxygen species and the antioxidant response in neutrophils. For that purpose seven male divers performed an immersion at a depth of 40 m for 25 min. The same parameters were measured after an hyperbaric oxygen (HBO) treatment at resting conditions in a hyperbaric chamber. Lymphocyte H₂O₂ production rose after diving and after HBO treatment. Glutathione peroxidase (GPx) and catalase activities increased after diving in lymphocytes, while after HBO exposure only increased GPx activity. Lymphocyte HO-1 mRNA expression increased after diving and after HBO exposure, while iNOS levels and nitrite levels significantly increased after diving. The hyperoxia associated to scuba diving leads to a condition of oxidative stress with increased lymphocyte H₂O₂ production, HO-1 expression, NO synthesis and antioxidant enzyme adaptations in order to avoid oxidative damage.     

Inhibition of growth and decreased survival of B104 rat neuroblastoma cells after exposure to hyperbaric oxygen

Summary The toxic effects of hyperbaric oxygen (HBO) on growth and survival of B104 rat neuroblastoma cells were investigated. Cells in log phase growth were incubated at 37°C with 10 atm O₂ for 1 to 4 h. After exposure to HBO, cells were monitored for their subsequent growth and survival. Two hours of exposure caused a slowing of growth, which returned to normaly by the end of the 7th d of the postexposure period. Exposures to O₂ of 3 h or longer caused a complete cessation of growth for 4 d after the exposure and very litle or no recovery after this period. Increased hydrostatic pressure for 6 h using helium as the inert gas had no effect on growth. A colony formation assay was used to quantitative the degree of cell death induced by HBO. The resulting survival curve was of the exponential type with a broad shoulder between 0 to 2.5 h of exposure to 10 atm O₂. The curve fell off sharply at 2.5 h with an exponential decrease in survival when the exposure to HBO was extended to 4 h. At 2 h about 50% of cells were killed, but at 4 h only 2% survived the treatment. These results show that the depression of the growth rate by HBO is related to the number of cells that are killed by the exposure. This system provides a model in which the molecular and cellular effects of HBO can be investigated. This work was supported by the National Institutes of Health, Bethesda, MD, Grants AM-21423 and CA-14489, and by grants from the W. W. Smith Foundation and the Philadelphia Foundation. The studies presented here are part of a dissertation submitted by G. J. Gendimenico in partial fulfillment of the requirements for the degree of Ph.D. in pharmacology from the University of Pennsylvania.     

氦氧饱和高气压暴露对铜绿假单胞菌PAO1基因表达的诱导调节

研究氦氧饱和高气压暴露对铜绿假单胞菌基因表达谱的系统影响,对急性毒力基因表达的调节。用全基因组DNA芯片分析技术比较菌株暴露前后基因表达谱差异;RT-PCR方法验证部分差异表达基因;用分光光度法在细胞水平验证弹性蛋白酶含量;小鼠染毒法观察暴露组细菌毒力在整体动物水平的变化。基因表达谱分析结果表明,铜绿假单胞菌暴露12 h差异表达基因达243个、72 h差异表达基因为1 168个。72 h差异表达基因中与细菌应激响应、蛋白折叠、转录调节、菌毛和鞭毛合成、毒力因子调节与合成、细菌外膜蛋白和抗原合成的基因大量上调;部分基因的RT-PCR验证结果与芯片结果一致;细胞水平验证结果显示暴露72 h细菌毒力表型增强。因此,氦氧饱和高气压暴露对铜绿假单胞菌基因表达谱有明显影响,对急性侵袭性感染毒力因子基因表达水平有正向诱导调节作用。     

Hyperbaric oxygen therapy treatment for the fixation of implant prosthesis in oncology patients irradiated

doi: 10.1111/j.1741‐2358.2012.00636.x Hyperbaric oxygen therapy treatment for the fixation of implant prosthesis in oncology patients irradiated Objectives: This study aimed to present a clinical report of an irradiated oncologic patient who underwent hyperbaric oxygen therapy to be rehabilitated with implant‐supported prosthesis. Materials and Methods: A 67‐year‐old man was admitted at Oral Oncology Center (FOA‐UNESP) presenting a lesion on the mouth floor. After clinical evaluation, incisional biopsy and histopathological exam, a grade II squamous cell carcinoma was diagnosed. The patient was subjected to surgery to remove the lesion and partial glossectomy. Afterwards, the radiotherapy, in the left/right cervicofacial area of the supraclavicular fossa, was conducted. After 3 years of the surgery, the patient was submitted to hyperbaric oxygen therapy. Then, four implants were installed in patient’s mandible. Five months later, an upper conventional complete denture and lower full‐arch implant‐supported prosthesis were fabricated. Conclusion: The treatment resulted in several benefits such as improving his chewing efficiency, swallowing and speech, less denture trauma on the mucosa and improving his self‐esteem.     

Hyperbaric oxygen therapy suppresses hypoxia and reoxygenation injury to retinal pigment epithelial cells through activating peroxisome proliferator activator receptor-alpha signalling

Retinal ischemia followed by reperfusion (IR) is a common cause of many ocular disorders, such as age-related macular degeneration (AMD), which leads to blindness in the elderly population, and proper therapies remain unavailable. Retinal pigment epithelial (RPE) cell death is a hallmark of AMD. Hyperbaric oxygen (HBO) therapy can improve IR tissue survival by inducing ischemic preconditioning responses. We conducted an in vitro study to examine the effects of HBO preconditioning on oxygen–glucose deprivation (OGD)-induced IR-injured RPE cells. RPE cells were treated with HBO (100% O₂ at 3 atmospheres absolute for 90 min) once a day for three consecutive days before retinal IR onset. Compared with normal cells, the IR-injured RPE cells had lower cell viability, lower peroxisome proliferator activator receptor-alpha (PPAR-α) expression, more severe oxidation status, higher blood-retinal barrier disruption and more elevated apoptosis and autophagy rates. HBO preconditioning increased PPAR-α expression, improved cell viability, decreased oxidative stress, blood-retinal barrier disruption and cellular apoptosis and autophagy. A specific PPAR-α antagonist, GW6471, antagonized all the protective effects of HBO preconditioning in IR-injured RPE cells. Combining these observations, HBO therapy can reverse OGD-induced RPE cell injury by activating PPAR-α signalling.     

高气压对脑循环的影响

对32名男性潜水员和25头家兔进行了下列3项内容的观察:1)不同压力下脑阻抗图(REG)的改变;2)模拟潜水时REG的变化与颅内压(ICP)的关系;3)职业潜水员的工令对脑循环的影响。结果表明,在高气压下,REG的波幅、dz/dt和上升时间/心动周期比值均有不同程度的变化。这些指标的变化可以说明博动性脑血容量减少和血管阻力增加,提示脑血流量减少。这些变化主要是由于高分压氧的作用。     

高压氧与降纤酶综合治疗脑血栓形成42例分析

目的：探讨高压氧与降纤酶结合治疗脑血栓形成的疗效。方法：把124例脑血栓形成患者随机分为A组、B组、C组,A组42例采用高压氧加降纤酶治疗;B组38例采用降纤酶治疗;C组44例采用常见规治疗。并分析和比较3组患者的治疗效果。结果A组治愈率80．36％,同时治疗前后血液流变学检查血浆比粘度、红细胞压积、低切变等差异有非常显著性意义（P＜0．01）;B组治愈率61．3％;C组治愈率52．3％。三组患者治愈率差异有显著意义（P＜0．01）。结论高压氧与降纤酶联合治疗脑血栓形成的效果优于常规组和单纯降纤酶治疗组的治疗效果,并能改善血液粘调度,是治疗脑血栓形成的好方法。     

Autologous bone marrow mononuclear cell infusion and hyperbaric oxygen therapy in type 2 diabetes mellitus: an open-label,randomized controlled clinical trial

Background aimsThe use of bone marrow mononuclear cells (BM-MNCs) has achieved great outcomes in clinical practice. We aim to evaluate the efficacy and safety of autologous BM-MNC infusion and hyperbaric oxygen therapy (HOT) in type 2 diabetes mellitus.MethodsThis single-center, randomized, open-label, controlled clinical trial with a factorial design included two phases. The patients received standard medical therapy in the run-in phase; in the treatment phase, patients with glycated hemoglobin of 7.5–9.5% were randomly assigned into four groups and underwent BM-MNC infusion along with HOT (BM-MNC+HOT group), BM-MNC infusion (BM-MNC group), HOT (HOT group) and standard medical therapy (control group), respectively. The area under the curve of C-peptide was recorded as a primary end point. Our research is registered at ClinicalTrials.gov (NCT00767260).ResultsA total of 80 patients completed the follow-up. At 12 months after treatment, the area under the curve of C-peptide (ng/mL per 180 min) of the BM-MNC+HOT group and the BM-MNC group were significantly improved (34.0% and 43.8% from the baseline, respectively). The changes were both significant compared with that in the control group, but no remarkable change was observed in the HOT group. Treatment-related adverse events were mild, including transient abdominal pain (n = 5) and punctual hemorrhage (n = 3).ConclusionsBM-MNC infusion for type 2 diabetes mellitus improves islet function and metabolic control, with mild adverse effects. HOT does not synergize with BM-MNC infusion.     

综述与专论: 高压氧疗法治疗脑缺血的相关机制

脑缺血是指大脑各部分血液供应不足导致脑组织缺血缺氧,进而导致密集缺血区脑组织出现不可逆的损伤坏死,其高致残率、高死亡率会对患者及其家庭造成严重的伤害。在脑缺血发生后,及时采取一定的治疗措施控制梗死灶的大小,并挽救半暗带中的细胞是脑缺血预后的关键。高压氧疗法是针对脑缺血的一种潜在治疗方法,在近年来得到了越来越广泛的关注和研究,本文旨在综述近年来国内外关于高压氧疗法治疗脑缺血的相关机制及研究进展,为脑缺血患者的治疗和预后提供新思路。