Undersea biomedical research最新文献

Effects of hyperoxia on human endothelial cell proliferation and morphology in vitro. 高氧对体外人内皮细胞增殖和形态的影响。

Undersea biomedical research Pub Date : 1992-11-01

R Bjerkvig, J Thorsen, E Svendsen, H Holmsen, T Thorsen

{"title":"Effects of hyperoxia on human endothelial cell proliferation and morphology in vitro.","authors":"R Bjerkvig, J Thorsen, E Svendsen, H Holmsen, T Thorsen","doi":"","DOIUrl":"","url":null,"abstract":"The effects of hyperoxia on endothelial cells from human umbilical veins were studied in vitro by flow cytometric DNA analysis, cell proliferation, and morphology. Exposure of the cells to PO2 of approximately 400 and 500 mmHg (corresponding to O2 concentrations of 65 and 95%, respectively) caused, after 24 h, an increase in the proportion of S-phase cells from 18 to 33%. This was followed by a dramatic decrease of S-phase cells to about 4% after 48 h of O2 exposure. This decrease was also sustained after 72 h of O2 treatment. Concomitant with the depletion of S-phase cells was an increase from 13 to 21% in the proportion of cells in the G2M phase, indicating that cells were unable to undergo cell division after a 48-h exposure to 65 and 95% O2. Cells exposed to various PO2 levels (124, 248, 400, and 500 mmHg) showed a dose-dependent reduction in cell proliferation leading to a total inhibition of cell growth after exposure to PO2 of 400 and 500 mmHg. Cells exposed to 248 mmHg PO2 exhibited similar growth rates as the control cells during the first 3 days. Thereafter there was a 50% reduction in cell density as compared to the control cells. Light and scanning electron microscopy showed that the hyperoxic cells underwent morphologic changes characterized by cell contraction and swelling. Thus it is shown that exposure to very high PO2 tensions first stimulates the cells to enter the S phase of the cell cycle. Thereafter changes take place leading to a nearly complete reduction of cell proliferation.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 6","pages":"415-26"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12479436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Description and evaluation of a simple method for microbiological studies on otitis externa. 外耳炎微生物学研究的一种简单方法的描述和评价。

Undersea biomedical research Pub Date : 1992-11-01

W L Dibb

{"title":"Description and evaluation of a simple method for microbiological studies on otitis externa.","authors":"W L Dibb","doi":"","DOIUrl":"","url":null,"abstract":"A simple cultural method for identification of the bacteria and yeasts likely to cause external otitis in divers is described. The method employs a commercial dip-slide system (Urotube) in which ear swabs are rolled onto the three agar surfaces, spread by a loop, and then incubated for a period of 18 h or more at 37 degrees C. The method was compared with traditional culture methodology on agar plates. Use of reference strains of bacteria and stored clinical isolates of bacteria and yeasts from ear infections showed stable patterns of growth for each species. Semiquantitative investigation of growth showed that there was a constant relationship between amount of growth on agar plates as compared to the dip-slide. Results were reproducible and were not affected by prolonged incubation. Directly inoculated swabs from normal ear canals and clinically infected ear canals showed identical findings by the traditional culture and Urotube methods. The Urotube method has also been evaluated in practical situations offshore with favorable experience. The Urotube method thus provides a rapid and simple way of identifying the causes of external otitis in divers in isolated areas where laboratory facilities are not readily available. This can have consequences for speed and choice of therapy in isolated environments.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 6","pages":"463-9"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12478670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Americans with Disabilities Act and the injured diver. 《美国残疾人法案》和受伤的潜水员。

Undersea biomedical research Pub Date : 1992-11-01

C G Daugherty

引用次数: 0

Effects of an increased PO2 during recompression therapy for the treatment of experimental cerebral arterial gas embolism. PO2升高对实验性脑动脉气体栓塞再压迫治疗的影响。

Undersea biomedical research Pub Date : 1992-11-01

J J McDermott, A J Dutka, W A Koller, E T Flynn

{"title":"Effects of an increased PO2 during recompression therapy for the treatment of experimental cerebral arterial gas embolism.","authors":"J J McDermott, A J Dutka, W A Koller, E T Flynn","doi":"","DOIUrl":"","url":null,"abstract":"In this study we investigated the efficacy of an initial compression to 6 atm abs on a 53% nitrogen:47% oxygen mixture (PO2 = 2.8 atm abs) before breathing oxygen at 2.8 and 1.9 atm abs for the treatment of feline cerebral arterial gas embolism. Neurophysiologic function was determined by measuring the cortical somatosensory evoked potential (SEP) amplitude in anesthetized ventilated cats. Air was infused into the carotid artery until the SEP amplitude was reduced to less than 10% of baseline values. The animals were randomly separated into 3 groups. The first group (CONTROL) (n = 7) served as control and remained at the surface, breathing air. The second group (NITROX) (n = 10) was compressed to 6 atm abs breathing a 53:47% nitrox mixture for 30 min followed by breathing 100% oxygen at 2.8 and 1.9 atm abs. The third group (HBO) (n = 10) was compressed to 2.8 and 1.9 atm abs breathing 100% oxygen. Air infusion suppressed the SEP amplitude to the same level in all groups. The CONTROL group recovered 27.6 +/- 31.2% (mean +/- standard deviation) of the baseline SEP amplitude, whereas the NITROX group recovered 63.2 +/- 28.2%, and the HBO group recovered 66.0 +/- 19.3%. An analysis of variance with repeated measures revealed that both treatment profiles promote significant (P = 0.03) recovery of the SEP amplitude compared to no treatment. We find no additional benefit, however, by initiating treatment at 6 atm abs, even when additional oxygen is provided.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 6","pages":"403-13"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12479435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Saturation decompression schedules based on a critical tissue supersaturation criterion. 基于临界组织过饱和度标准的饱和减压时间表。

Undersea biomedical research Pub Date : 1992-11-01

S V Rodchenkov, V K Skudin

引用次数: 0

Pneumothorax as a complication of recompression therapy for cerebral arterial gas embolism. 脑动脉气体栓塞再压迫治疗并发气胸。

Undersea biomedical research Pub Date : 1992-11-01

J R Broome, D J Smith

引用次数: 0

Physiologically and subjectively acceptable breathing resistance in divers' breathing gear. 潜水员呼吸装置的生理和主观可接受的呼吸阻力。

Undersea biomedical research Pub Date : 1992-11-01

D E Warkander, W T Norfleet, G K Nagasawa, C E Lundgren

{"title":"Physiologically and subjectively acceptable breathing resistance in divers' breathing gear.","authors":"D E Warkander, W T Norfleet, G K Nagasawa, C E Lundgren","doi":"","DOIUrl":"","url":null,"abstract":"To determine acceptable levels of breathing resistance in divers' gear, 6 subjects were exposed to varying levels of breathing resistance under demanding and realistic conditions. The immersed air-breathing subjects exercised in the prone position at 60% of their maximum oxygen uptake for 25 min in a hyperbaric chamber at 1.45 and 6.8 atm abs (145 and 690 kPa, 4.5 and 57 msw, 15 and 190 fsw). The breathing resistance ranged from minimal to 8-12 cmH2O (0.8-1.2 kPa).liter-1.s at flow rates of 2-3 liter/s. The higher resistance levels interfered with the respiration in terms of end-tidal PCO2 and dyspnea scores. There were considerable individual differences, and changes in one parameter were typically not paralleled by changes in the other. None of maximal voluntary ventilation, forced expiratory volume, expiratory reserve volume, vital capacities, or oxygen uptake was influenced by resistance. We set the maximum allowable end-tidal PCO2 at 60 mmHg and maximum dyspnea score at 1.0 on a scale from 0 (none) to 3 (severe). Based on these criteria we concluded that the external work of breathing should not exceed 1.5-2.0 J/liter in the ventilation range 30 to 75 liter/min BTPS.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 6","pages":"427-45"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12479437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Posterior shoulder dislocation and humeral head necrosis in a recreational scuba diver with diabetes. 休闲潜水伴糖尿病的后肩脱位和肱骨头坏死。

Undersea biomedical research Pub Date : 1992-11-01

D F Gorman, M J Sandow

引用次数: 0

Human brainstem auditory-evoked potentials in deep experimental diving to pressures up to 62.5 bar. 人类脑干听觉诱发电位在深度实验潜水压力高达62.5巴。

Undersea biomedical research Pub Date : 1992-09-01

J Lorenz, G Athanassenas, P Hampe, G Plath, J Wenzel

{"title":"Human brainstem auditory-evoked potentials in deep experimental diving to pressures up to 62.5 bar.","authors":"J Lorenz, G Athanassenas, P Hampe, G Plath, J Wenzel","doi":"","DOIUrl":"","url":null,"abstract":"The neural mechanisms underlying the high pressure neurologic syndrome (HPNS), which limit man's safe advance to extreme diving depths, are still unclear. This work was aimed at a better understanding of HPNS through study of brainstem auditory-evoked potentials (BAEP). BAEP were repeatedly recorded within 2 experimental chamber dives, Titan VIII (2 divers, maximum depth of 560 msw, compression time to bottom 109 h) and Titan XI (3 divers, maximum depth of 615 msw, compression time to bottom 240 h). Prolongation of the IV/V-complex occurred in 2 divers upon reaching 525 msw during Titan VIII compression and was accompanied by vestibular disturbances and amplitude increases of finger tremor. Both categories of changes--clinical signs and IV/V delay--gradually diminished during a 4-day stay at 545 msw, suggesting that they depended on excessive compression rates and insufficient acclimation time. Longer holding times at intermittent depths during Titan XI clearly reduced both HPNS symptoms and magnitude of prolongation of IV/V latencies. Wave I and wave III latency did not significantly change, pointing to a suppression of pontomesencephalic transmission. We infer that pressure suppresses synaptic transmission or triggers an increase of cortical or subcortical efferent inhibitory modulation of upper pontine and midbrain auditory afferents. Postdive controls revealed no persistent changes of BAEP measures in either the Titan VIII or XI divers.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 5","pages":"317-30"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12529199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High pressure effects on reflexes in isolated spinal cords of newborn rats. 高压对新生大鼠脊髓反射的影响。

Undersea biomedical research Pub Date : 1992-09-01

A Tarasiuk, D Schleifstein-Attias, Y Grossman

{"title":"High pressure effects on reflexes in isolated spinal cords of newborn rats.","authors":"A Tarasiuk, D Schleifstein-Attias, Y Grossman","doi":"","DOIUrl":"","url":null,"abstract":"High pressure induces hyperexcitability and convulsions in both intact and decerebrated animals. However, pressure suppresses synaptic transmission in isolated invertebrate preparations. We examined the effect of high pressure on monosynaptic (MSR) and polysynaptic (PSR) reflexes in isolated spinal cords of newborn rats. Reflex activity was recorded extracellularly from the cut ends of the lumbar ventral roots L3-L5 following stimulation of the corresponding dorsal roots. Increasing the stimulus frequency from 0.1 to 2.0 Hz reduced the amplitude of both reflexes by 75%. High pressure (10.1 MPa helium) did not affect this phenomenon. Pressure had no effect on MSR amplitude, but increased PSR amplitude by 30%. For MSR, pressure increased the latency by 25%, duration by 20%, and rise time by 25%. Pressure abolished the moderate (119 +/- 4.5%, mean +/- SEM) posttetanic potentiation observed at 0.1 MPa. For the curve relating MSR amplitude to [Ca2+]o, high pressure produced a slight rightward shift of 0.25 mM without affecting its saturation level. These data suggest that the response of vertebrate central synapses to pressure may be different from previously described invertebrate synapses. Alternatively, if synaptic potentials are reduced at high pressure, other processes that determine excitability must be invoked to account for the relatively stabile reflex response.","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 5","pages":"331-7"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12682727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0