Undersea biomedical research最新文献

{"title":"A system for saturating in vitro preparations with high pressure O2, He, H2, and mixtures.","authors":"G Imbert,&nbsp;J S Colton,&nbsp;W Long,&nbsp;Y Grossman,&nbsp;H J Moore","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Saturation of a liquid with gas before perfusing a tissue or cellular preparation under pressure can be achieved by bubbling the gas through the liquid. A container for this purpose that is housed in the pressure chamber with the preparation allows saturation of the liquid under hyperbaric conditions. Sealing the container allows saturation with a gas different from the gas used to compress the pressure chamber. If the pressure within the sealed container is maintained at a slightly higher level, the bubbling gas can also provide the driving force for the liquid to flow to the preparation. Based on this concept, an apparatus was built and tested to pressures of 6.8 MPa. This paper describes the saturator and the associated circuitry used to control bubbling gas pressure relative to the pressure vessel, gas flow through the saturator, and liquid flow to the preparation. A special application in the case of hydrogen gas is described, where this system has added safety advantages.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 1","pages":"49-53"},"PeriodicalIF":0.0,"publicationDate":"1992-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12705058","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}

{"title":"Program and abstracts. Undersea and Hyperbaric Medical Society annual scientific meeting. 23-27 June 1992, Bethesda, Maryland.","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 Suppl ","pages":"1-161"},"PeriodicalIF":0.0,"publicationDate":"1992-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12761765","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}

{"title":"Hyperbaric oxygenation decreases blood flows in normal and septic rats.","authors":"K H Muhvich,&nbsp;M R Piano,&nbsp;R A Myers,&nbsp;J L Ferguson,&nbsp;L Marzella","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The purpose of the study reported here was to characterize the effects of acute exposure to 100% oxygen at a pressure of 202.6 kPa on hemodynamics and organ blood flow in antibiotic-controlled bacterial sepsis. An abscess containing known numbers and strains of live Escherichia coli and Bacteroides fragilis was established in the peritoneal cavity of rats. Sham-operated rats were used as controls. Cardiac output, fractional blood flow distribution, and blood flow were calculated from data obtained using the radiolabeled microsphere technique. Myocardial and renal blood flows were decreased (20-30%) in both experimental groups during hyperbaric oxygen (HBO) exposure. Renal blood flow remained diminished for at least 20 min after rats were removed from the hyperbaric chamber. Adrenal gland perfusion in abscess-containing rats was reduced both during and after HBO exposure. Skeletal muscle blood flow (quadriceps and gastrocnemius muscles) was reduced by one third in both experimental groups 20 min after acute exposure to HBO. The results of this study indicate that changes in organ perfusion induced by HBO are similar in abscess-containing and normal rats. We conclude that HBO does not alter the regulation of blood flow in antibiotic-controlled sepsis.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"19 1","pages":"31-40"},"PeriodicalIF":0.0,"publicationDate":"1992-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12705056","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}

{"title":"Effect of He-O2, O2, and N2O-O2 breathing on injected bubbles in spinal white matter.","authors":"O Hyldegaard,&nbsp;M Møller,&nbsp;J Madsen","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Injected air bubbles in spinal white matter in the rat were studied at 1 bar after decompression from an exposure to air at 3.1 bar (absolute) for 4 h. During air breathing all injected bubbles grew for the first 2 h of the observation period. Thereafter three of nine bubbles began to shrink and one of them disappeared. During breathing of heliox (80:20) bubbles consistently shrank and disappeared from view. If the breathing gas was changed from heliox to N2O-O2 (80:20), while bubbles still had an appreciable size, they started growing again. If the change to N2O-O2 was done after a bubble disappeared from view, it did not reappear. During breathing of 100% oxygen, all bubbles initially grew. Subsequently they all shrank and disappeared at about the same time after gas shift, as during heliox breathing. The effect of heliox treatment on CNS decompression sickness after air dives is discussed.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"18 5-6","pages":"361-71"},"PeriodicalIF":0.0,"publicationDate":"1991-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12908721","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}

{"title":"Daily diving pattern of Korean and Japanese breath-hold divers (ama).","authors":"S K Hong,&nbsp;J Henderson,&nbsp;A Olszowka,&nbsp;W E Hurford,&nbsp;K J Falke,&nbsp;J Qvist,&nbsp;P Radermacher,&nbsp;K Shiraki,&nbsp;M Mohri,&nbsp;H Takeuchi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Daily diving patterns and thoracic skin and sea-water temperatures were recorded during the entire work shift of Korean female unassisted (cachido) and Japanese male unassisted and partly assisted (funado) divers using Underwater Physiological Data Loggers developed in Buffalo and Japan. All 3 groups of divers were studied during the summer of 1989 and 1990. Additional studies were conducted during the winter of 1991 on Korean female divers who, unlike Japanese divers, dive all year round. The water temperature of the diving grounds in summer was 24 degrees C in both Korea and Japan, and 10 degrees C during winter in Korea. Both Korean female and Japanese male cachido divers made 113-138 dives a day and stayed in the water a total of 170-200 min.day-1, of which only 52-63 min were spent diving submerged, and the remaining time at the water surface. These diving patterns were not different between female and male cachido divers. Compared with Japanese male divers, Korean female divers dived to a shallower depth (3.7 vs. 6.9 m) with shorter dive time (29 vs. 37 s) and shorter bottom time (14 vs. 18 s). Velocities of descent (0.72 vs. 0.47 m.s-1) and ascent (0.77 vs. 0.56 m.s-1) were also slower in female divers than in male divers. The diving pattern of Korean female divers was similar in both summer and winter. Although all cachido divers wore wet suits and thus were protected from severe cold stress, thoracic skin temperature decreased during a work shift by 7 degrees C in winter (vs. 1 degree C in summer) in Korean divers. Compared with Japanese male cachido divers, Japanese male funado divers stayed in the diving ground (including time in the boat) longer (201 vs. 305 min.day-1) but performed only 23 dives per day. The average diving depth (9.7 m), duration (69 s), and bottom time for each dive (45 s), however, were significantly greater in funados. The velocity of vertical descent (1.0 m.s-1) was also significantly greater in funados because they descend with a weight (8-12 kg). The rate of ascent was not different.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"18 5-6","pages":"433-43"},"PeriodicalIF":0.0,"publicationDate":"1991-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12909374","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}

{"title":"Assessment of inter-rater agreement on the grading of intravascular bubble signals.","authors":"K D Sawatzky,&nbsp;R Y Nishi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Transcutaneous Doppler ultrasonic bubble detectors are widely used in decompression research. However, interpretation of the complex acoustic signals from the bubble detectors involves a degree of subjectivity, and the comparability of grades assigned by different raters must be assessed. Hypothetical data were used to determine an appropriate method for evaluating the comparability of Doppler raters and to illustrate the limitations of many nonparametric statistics. Two sets of real data were then used to evaluate this procedure, the first from a training exercise carried out by Kisman and Masurel (1978, unpublished) and the second from a test tape that was independently scored by five Defence and Civil Institute of Environmental Medicine Doppler technicians. The results were analyzed by a two-stage approach. First, they were entered into contingency tables and checked for large disagreements, a tendency for one rater to grade higher than the other, and the degree of variability. Second, the results were analyzed with the nonparametric weighted kappa statistic. These studies have led to a practical, efficient method for the evaluation of Doppler raters.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"18 5-6","pages":"373-96"},"PeriodicalIF":0.0,"publicationDate":"1991-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12908722","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}

{"title":"Psychophysiologic changes in sleep during simulated 200-m heliox saturation dives.","authors":"K Ozawa,&nbsp;A Hashimoto,&nbsp;H Oiwa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The standard polysomnogram and questionnaire were measured from 4 subjects during 2 simulated 200-m heliox saturation dives. These measurements were performed for 1 precompression night, bottom nights, 4 or 5 nights during decompression, and 1 postdecompression night. Although the subjects reported a marked decrease in quantity and quality of sleep at the bottom, only a slight degree of sleep disturbance caused by frequent awakenings was found in polysomnograms. Throughout the dive period, latency of each sleep stage, quantity of REM sleep, and the REM-NREM cycle showed no changes, whereas quantity of slow wave sleep remained at a low level. From these results it was inferred that basic sleep mechanisms were not affected under 200-m heliox environment. Unusual physiologic phenomena were observed during the dive period. Intermittent diffuse rhythmic theta activity was found in 1 subject at sleep stage REM during the bottom. Rhythmic contraction of facial muscles, which was similar to bruxism, increased, particularly at sleep stage 2 in all subjects during decompression.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"18 5-6","pages":"397-412"},"PeriodicalIF":0.0,"publicationDate":"1991-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12908724","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}

{"title":"Effects of four drugs on 4-aminopyridine seizures: a comparison with their effects on HPNS.","authors":"B Wardley-Smith,&nbsp;K T Wann","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The effects of two i.v. anesthetics, Saffan and methohexitone (MHX) and two N-methyl-D-aspartate receptor antagonists, MK-801 (Dizocilpine) and 2-aminophosphonoheptanoate (AP7), were tested for activity against the motor excitation (tremor, whole body jerks, and seizures) produced by the K+ channel blocker 4-aminopyridine (4-AP). Saffan increased the dose of 4-AP required for all three endpoints; MHX had no effect on tremor but reduced the 4-AP required to produce jerks and seizures. MK-801 also reduced the 4-AP dose required to produce jerking but did not affect tremor or seizures. In contrast, AP7 increased the amount of 4-AP required to produce all endpoints. The effects of these drugs on 4-AP-induced excitation are similar to their actions on hyperbaric excitation, reported by us previously, and suggest that blockade of K+ channels may contribute to the high pressure nervous syndrome.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"18 5-6","pages":"413-9"},"PeriodicalIF":0.0,"publicationDate":"1991-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12909370","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}

{"title":"Case control study of cerebral perfusion deficits in divers using 99Tcm hexamethylpropylene amine oxime.","authors":"M Hodgson,&nbsp;D J Smith,&nbsp;M A Macleod,&nbsp;A S Houston,&nbsp;T J Francis","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In a preliminary report, Adkisson et al. (Lancet 1989; 2:119-121) used 99Tcm-hexamethylpropylene amine oxime (HMPAO) single photon emission computed tomography (SPECT) to provide evidence for cerebral perfusion deficits in 28 cases of dysbarism. The report caused concern because these deficits were found even in cases in which the clinical manifestations were limited to the spinal cord. To address this issue further, a case-control study of cerebral perfusion using 99Tcm-HMPAO SPECT is reported. Four groups of 10 subjects were studied: a) divers scanned on average 11 days after treatment of neurologic decompression illness, b) divers scanned 3-5 yr after treatment for neurologic decompression illness, c) diver controls, and d) population controls. All groups were matched for age, and the divers were further matched for general diving experience. The scans were randomized and reported blind to history. Despite a trend toward larger numbers of deficits in individuals with decompression illness, the 4 groups were statistically indistinguishable. Furthermore, no correlation was found between the location of the perfusion deficits and the clinical presentation. These results indicate that 99Tcm-HMPAO SPECT scanning requires further evaluation before clinical significance can be ascribed to perfusion deficits found in divers.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"18 5-6","pages":"421-31"},"PeriodicalIF":0.0,"publicationDate":"1991-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12909371","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}

{"title":"Venous gas emboli and complement activation after deep repetitive air diving.","authors":"J Zhang,&nbsp;C E Fife,&nbsp;M S Currie,&nbsp;R E Moon,&nbsp;C A Piantadosi,&nbsp;R D Vann","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Complement activity has been linked to decompression sickness (DCS), but the effects of intravascular bubbles on complement activation are poorly understood. We have investigated intravascular complement activation by measuring red blood cell (RBC)-bound C3d after repetitive air diving in man. Subjects were exposed to a single, 20 min, 170 fsw (feet of sea water) dive, or to 2 such dives with a 6-h surface interval. Doppler monitoring for venous gas emboli was performed postdive. Predive blood samples were studied to determine sensitivity of complement to activation by air bubbles. Other predive and postdive venous samples were evaluated for intravascular complement activation. No cases of DCS occurred in 39 dives. Baseline complement sensitivity appeared normally distributed, thus \"sensitive\" and \"insensitive\" subjects were not clearly distinguishable. RBC-bound C3d did not increase after 1 dive but did increase after the repetitive dive (P less than 0.05). Furthermore, maximum bubble grade was independent of complement activation.</p>","PeriodicalId":76778,"journal":{"name":"Undersea biomedical research","volume":"18 4","pages":"293-302"},"PeriodicalIF":0.0,"publicationDate":"1991-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13047839","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}