Linking environmental factors with reflex action mortality predictors, physiological stress, and post-release movement behaviour to evaluate the response of white sturgeon (Acipenser transmontanus Richardson, 1836) to catch-and-release angling

White sturgeon are the largest freshwater fish in North America and are the focus of an intense catch-and-release (C&R) fishery; the effects are largely unknown. We assessed the effect of fight and handling time, water temperature, river discharge rate, and fish size on physiological and reflex impairment responses of wild white sturgeon to angling. Sixty of these fish were tagged with acoustic transmitters to assess survival and post-release behaviour. Survival was high (100%). Water temperature and discharge influenced post-capture blood physiology. Specifically, lactate, chloride, and cortisol concentrations were elevated in individuals fought longer, and captured at higher water temperatures and river discharge. Cortisol was affected by fish size, with lower concentrations found in larger individuals. Only lactate and chloride were positively related to reflex impairment scores. Post-release movements were correlated with physiological state, fight characteristics and the environment. Specifically, higher blood lactate and chloride and those with longer fight times moved shorter distances after release. Contrastingly, higher levels of circulating glucose and potassium, as well as larger fish captured during periods of high discharge moved longer distances. Sturgeon tended to move shorter distances and at slower rates when reflex impairment was high, although reflex impairment in general did not explain a significant proportion of the variance in any movement metric. Our results show intriguing variance in the physiological and behavioural response of individual white sturgeon to C&R angling, with some degree of environmental dependence, and highlights the importance of understanding drivers of such variation when managing fisheries.

Thiamine Levels in Muscle and Eggs of Adult Pacific Salmon from the Fraser River, British Columbia

Multiple species and stocks of Pacific salmon Oncorhynchus spp. have experienced large declines in the number of returning adults over a wide region of the Pacific Northwest due to poor marine survival (low smolt-to-adult survival rates). One possible explanation for reduced survival is thiamine deficiency. Thiamine (vitamin B₁ ) is an essential vitamin with an integral role in many metabolic processes, and thiamine deficiency is an important cause of salmonid mortality in the Baltic Sea and in the Laurentian Great Lakes. To assess this possibility, we (1) compared muscle thiamine content over time in a holding experiment using Fraser River (British Columbia) Sockeye Salmon O. nerka to establish whether adults that died during the holding period had lower thiamine levels than survivors, (2) measured infectious loads of multiple pathogens in held fish, and (3) measured egg thiamine content from four species of Pacific salmon collected on Fraser River spawning grounds. Chinook Salmon O. tshawytscha had the lowest egg thiamine, followed by Sockeye Salmon; however, egg thiamine concentrations were above levels known to cause overt fry mortality. Thiamine vitamers in the muscle of Fraser River adult Sockeye Salmon shifted over a 13-d holding period, with a precipitous decline in thiamine pyrophosphate (the active form of thiamine used in enzyme reactions) in surviving fish. Survivors also carried lower loads of Flavobacterium psychrophilum than fish that died during in the holding period. Although there is no evidence of thiamine deficiency in the adults studied, questions remain about possible thiamine metabolism-fish pathogen relationships that influence survival.

Survival Rates of Out-Migrating Yearling Chinook Salmon in the Lower Columbia River and Plume after Exposure to Gas-Supersaturated Water

In 2011, unusually high flows caused total dissolved gas (TDG) levels in the Columbia River, USA, to escalate well above the 120% regulatory limit that was imposed to prevent harmful impacts to aquatic organisms. After observing gas bubble trauma (GBT) in dead yearling Chinook Salmon Oncorhynchus tshawytscha (smolts) held in tanks, we compared estimated survival rates of acoustic-tagged in-river-migrating (IR) and transported (TR) smolts that were released below Bonneville Dam prior to and during the period of elevated TDG (>120%). The log odds of estimated daily survival in the lower river and plume was significantly lower for IR smolts that were released during elevated TDG (maximum possible exposure = 134%) than for IR smolts released when TDG was less than 120%. The TR smolts that were released 10-13 km below Bonneville Dam during elevated TDG had lower maximum possible exposure levels (126% TDG), and the log odds of estimated daily survival in the lower river and plume did not differ from that of TR smolts released when TDG was less than 120%. Direct mortality due to GBT is probably reduced in natural settings relative to laboratory experiments because smolts can move to deeper water, where pressure keeps gasses in solution, and can migrate downstream of the spillway, where TDG levels decrease as the river returns to equilibrium with the atmosphere. However, initially nonlethal GBT may reduce survival rates by increasing smolt susceptibility to predation and infection. Although our findings are limited by the observational nature of the study, our analysis is the first direct assessment of gas supersaturation's potential influence on survival of free-ranging smolts in the river and coastal ocean below a large dam. Experiments using simultaneous releases of control and gas-exposed groups are warranted and should consider the possibility that the chronic effects of TDG exposure on survival are important and persist into the early marine period. Received October 5, 2015; accepted August 18, 2016 Published online October 24, 2016.

Tracking wild sockeye salmon smolts to the ocean reveals distinct regions of nocturnal movement and high mortality

Few estimates of migration rates or descriptions of behavior or survival exist for wild populations of out-migrating Pacific salmon smolts from natal freshwater rearing areas to the ocean. Using acoustic transmitters and fixed receiver arrays across four years (2010-2013), we tracked the migration of > 1850 wild sockeye salmon (Oncorhynchus nerka) smolts from Chilko Lake, British Columbia, to the coastal Pacific Ocean (> 1000 km distance). Cumulative survival to the ocean ranged 3-10% among years, although this may be slightly underestimated due to technical limitations at the final receiver array. Distinct spatial patterns in both behavior and survival were observed through all years. In small, clear, upper-river reaches, downstream migration largely occurred at night at speeds up to 50 km/d and coincided with poor survival. Among years, only 57-78% of smolts survived the first 80 km. Parallel laboratory experiments revealed excellent short-term survival and unhindered swimming performance of dummy-tagged smolts, suggesting that predators rather than tagging effects were responsible for the initial high mortality of acoustic-tagged smolts. Migration speeds increased in the Fraser River mainstem (~220 km/d in some years), diel movement patterns ceased, and smolt survival generally exceeded 90% in this segment. Marine movement rates and survival were variable across years, with among-year segment-specific survival being the most variable and lowest (19-61%) during the final (and longest, 240 km) marine migration segment. Osmoregulatory preparedness was not expected to influence marine survival, as smolts could maintain normal levels of plasma chloride when experimentally exposed to saltwater (30 ppt) immediately upon commencing their migration from Chilko Lake. Transportation of smolts downstream generally increased survival to the farthest marine array. The act of tagging may have affected smolts in the marine environment in some years as dummy-tagged fish had poorer survival than control fish when transitioned to saltwater in laboratory-based experiments. Current fisheries models for forecasting the number of adult sockeye returning to spawn have been inaccurate in recent years and generally do not incorporate juvenile or smolt survival information. Our results highlight significant potential for early migration conditions to influence adult recruitment.

Tracking wild sockeye salmon smolts to the ocean reveals distinct regions of nocturnal movement and high mortality

Few estimates of migration rates or descriptions of behavior or survival exist for wild populations of out-migrating Pacific salmon smolts from natal freshwater rearing areas to the ocean. Using acoustic transmitters and fixed receiver arrays across four years (2010-2013), we tracked the migration of > 1850 wild sockeye salmon (Oncorhynchus nerka) smolts from Chilko Lake, British Columbia, to the coastal Pacific Ocean (> 1000 km distance). Cumulative survival to the ocean ranged 3-10% among years, although this may be slightly underestimated due to technical limitations at the final receiver array. Distinct spatial patterns in both behavior and survival were observed through all years. In small, clear, upper-river reaches, downstream migration largely occurred at night at speeds up to 50 km/d and coincided with poor survival. Among years, only 57-78% of smolts survived the first 80 km. Parallel laboratory experiments revealed excellent short-term survival and unhindered swimming performance of dummy-tagged smolts, suggesting that predators rather than tagging effects were responsible for the initial high mortality of acoustic-tagged smolts. Migration speeds increased in the Fraser River mainstem (~220 km/d in some years), diel movement patterns ceased, and smolt survival generally exceeded 90% in this segment. Marine movement rates and survival were variable across years, with among-year segment-specific survival being the most variable and lowest (19-61%) during the final (and longest, 240 km) marine migration segment. Osmoregulatory preparedness was not expected to influence marine survival, as smolts could maintain normal levels of plasma chloride when experimentally exposed to saltwater (30 ppt) immediately upon commencing their migration from Chilko Lake. Transportation of smolts downstream generally increased survival to the farthest marine array. The act of tagging may have affected smolts in the marine environment in some years as dummy-tagged fish had poorer survival than control fish when transitioned to saltwater in laboratory-based experiments. Current fisheries models for forecasting the number of adult sockeye returning to spawn have been inaccurate in recent years and generally do not incorporate juvenile or smolt survival information. Our results highlight significant potential for early migration conditions to influence adult recruitment.

Variability in Migration Routes Influences Early Marine Survival of Juvenile Salmon Smolts

Variability in animal migratory behavior is expected to influence fitness, but few empirical examples demonstrating this relationship exist. The initial marine phase in the migration of juvenile salmon smolts has been identified as a potentially critical life history stage to overall population productivity, yet how fine-scale migration routes may influence survival are unknown. Large-scale acoustic telemetry studies have estimated survival rates of outmigrant Pacific salmon smolts through the Strait of Georgia (SOG) along the British Columbian coastline to the Pacific Ocean, but these data have not been used to identify and characterize fine-scale movements. Data collected on over 850 sockeye salmon (Oncorhynchus nerka) and steelhead (Oncorhynchus mykiss) smolts detected at an array in the Strait of Georgia in 2004–2008 and 2010–2013 were analyzed to characterize migration routes and link movements to subsequent survival at an array 250 km further along the marine migration pathway. Both species exhibited disproportionate use of the most eastern route in the Strait of Georgia (Malaspina Strait). While many smolts moved across the northern Strait of Georgia acoustic array with no indication of long-term milling or large-scale east-to-west movements, large proportions (20–40% of sockeye and 30–50% of steelhead) exhibited a different behavior, apparently moving in a westward or counterclockwise pattern. Variability in migratory behavior for both species was linked to subsequent survival through the Strait of Georgia. Survival for both species was influenced by initial east-to-west location, and sockeye were further influenced by migration timing and duration of time spent near the northern Strait of Georgia array. Westward movements result in a net transport of smolts from Malaspina Strait to the Strait of Georgia, particularly for steelhead. Counterclockwise movements may be due to the currents in this area during the time of outmigration, and the higher proportion of steelhead smolts exhibiting this counterclockwise behavior may reflect a greater exposure to wind-altered currents for the more surface-oriented steelhead. Our results provide an empirical example of how movements can affect migration survival, for which examples remain rare in movement ecology, confirming that variability in movements themselves are an important part of the migratory process.

Immune response genes and pathogen presence predict migration survival in wild salmon smolts

We present the first data to link physiological responses and pathogen presence with subsequent fate during migration of wild salmonid smolts. We tagged and non-lethally sampled gill tissue from sockeye salmon (Oncorhynchus nerka) smolts as they left their nursery lake (Chilko Lake, BC, Canada) to compare gene expression profiles and freshwater pathogen loads with migration success over the first ~1150 km of their migration to the North Pacific Ocean using acoustic telemetry. Fifteen per cent of smolts were never detected again after release, and these fish had gene expression profiles consistent with an immune response to one or more viral pathogens compared with fish that survived their freshwater migration. Among the significantly upregulated genes of the fish that were never detected postrelease were MX (interferon-induced GTP-binding protein Mx) and STAT1 (signal transducer and activator of transcription 1-alpha/beta), which are characteristic of a type I interferon response to viral pathogens. The most commonly detected pathogen in the smolts leaving the nursery lake was infectious haematopoietic necrosis virus (IHNV). Collectively, these data show that some of the fish assumed to have died after leaving the nursery lake appeared to be responding to one or more viral pathogens and had elevated stress levels that could have contributed to some of the mortality shortly after release. We present the first evidence that changes in gene expression may be predictive of some of the freshwater migration mortality in wild salmonid smolts.

The effect of hatchery release strategy on marine migratory behaviour and apparent survival of Seymour River steelhead smolts (Oncorhynchus mykiss)

Early marine migratory behaviour and apparent survival of hatchery-reared Seymour River steelhead (Oncorhynchus mykiss) smolts was examined over a four year period (2006–2009) to assess the impact of various management strategies on improving early marine survival. Acoustically tagged smolts were released to measure their survival using estuary and coastal marine receivers forming components of the Pacific Ocean Shelf Tracking (POST) array. Early marine survival was statistically indistinguishable between releases of summer run and winter run steelhead races, night and day releases, and groups released 10 days apart. In 2009, the survival of summer run steelhead released into the river was again trialed against groups released directly into the ocean at a distance from the river mouth. Apparent survival was improved significantly for the ocean released groups. The health and physiological status of the various release groups were monitored in years 2007–2009, and results indicate that the fish were in good health, with no clinical signs of disease at the time of release. The possibility of a disease event contributing to early marine mortality was further examined in 2009 by vaccinating half of the released fish against common fish diseases (vibriosis, furunculosis). The results suggest that marine survival may be enhanced using this approach, although not to the extent observed when the smolts were transported away from the river mouth before release. In summary, direct experimental testing of different release strategies using the POST array to measure ocean survival accelerated the scientific process by allowing rapid collection of data which enabled the rejection of several existing theories and allowed tentative identification of several new alternative approaches that might improve early marine survival of Seymour River steelhead.

Spatio-temporal migration patterns of Pacific salmon smolts in rivers and coastal marine waters

Background

Migrations allow animals to find food resources, rearing habitats, or mates, but often impose considerable predation risk. Several behavioural strategies may reduce this risk, including faster travel speed and taking routes with shorter total distance. Descriptions of the natural range of variation in migration strategies among individuals and populations is necessary before the ecological consequences of such variation can be established.

Methodology/Principal Findings

Movements of tagged juvenile coho, steelhead, sockeye, and Chinook salmon were quantified using a large-scale acoustic tracking array in southern British Columbia, Canada. Smolts from 13 watersheds (49 watershed/species/year combinations) were tagged between 2004–2008 and combined into a mixed-effects model analysis of travel speed. During the downstream migration, steelhead were slower on average than other species, possibly related to freshwater residualization. During the migration through the Strait of Georgia, coho were slower than steelhead and sockeye, likely related to some degree of inshore summer residency. Hatchery-reared smolts were slower than wild smolts during the downstream migration, but after ocean entry, average speeds were similar. In small rivers, downstream travel speed increased with body length, but in the larger Fraser River and during the coastal migration, average speed was independent of body length. Smolts leaving rivers located towards the northern end of the Strait of Georgia ecosystem migrated strictly northwards after ocean entry, but those from rivers towards the southern end displayed split-route migration patterns within populations, with some moving southward.

Conclusions/Significance

Our results reveal a tremendous diversity of behavioural migration strategies used by juvenile salmon, across species, rearing histories, and habitats, as well as within individual populations. During the downstream migration, factors that had strong effects on travel speeds included species, wild or hatchery-rearing history, watershed size and, in smaller rivers, body length. During the coastal migration, travel speeds were only strongly affected by species differences.

An investigation into the poor survival of an endangered Coho salmon population

To investigate reasons for the decline of an endangered population of coho salmon (O. kisutch), 190 smolts were acoustically tagged during three consecutive years and their movements and survival were estimated using the Pacific Ocean Shelf Tracking project (POST) array. Median travel times of the Thompson River coho salmon smolts to the lower Fraser River sub-array were 16, 12 and 10 days during 2004, 2005 and 2006, respectively. Few smolts were recorded on marine arrays. Freshwater survival rates of the tagged smolts during their downstream migration were 0.0-5.6% (0.0-9.0% s.e.) in 2004, 7.0% (6.2% s.e.) in 2005, and 50.9% (18.6% s.e.) in 2006. Overall smolt-to-adult return rates exhibited a similar pattern, which suggests that low freshwater survival rates of out-migrating smolts may be a primary reason for the poor conservation status of this endangered coho salmon population.

Mechanisms influencing the timing and success of reproductive migration in a capital breeding semelparous fish species, the sockeye salmon

Two populations of homing sockeye salmon (Oncorhynchus nerka; Adams and Chilko) were intercepted in the marine approaches around the northern and southern ends of Vancouver Island (British Columbia, Canada) en route to a natal river. More than 500 salmon were nonlethally biopsied for blood plasma, gill filament tips, and gross somatic energy (GSE) and were released with either acoustic or radio transmitters. At the time of capture, GSE, body length, and circulating testosterone ([T]) differed between populations, differences that reflected known life-history variations. Within-population analyses showed that in Adams sockeye salmon, plasma glucose ([glu]), lactate ([lactate]), and ion concentrations were higher in the northern approach than in the southern approach, suggesting that the former was more stressful. GSE, [T], and gill Na(+),K(+)-ATPase activities also differed between the two locales, and each varied significantly with Julian date, suggesting seasonality. Despite these relative geographic differences, the timing of river entry and the ability to reach spawning areas were strongly correlated with energetic, reproductive, and osmoregulatory state. Salmon that delayed river entry and reached spawning areas had relatively high GSE and low [T] and gill ATPase. In contrast, salmon that entered the river directly but that ultimately failed to reach spawning areas had lower GSE and higher [T] and gill ATPase, and they also swam at significantly faster rates (failed fish approximately 20.0 km d(-1) vs. successful fish approximately 15.5 km d(-1)). Physiologically, salmon that did not enter the river at all but that presumably died in the marine environment exhibited high stress (plasma [glu] and [lactate]) and ionoregulatory measures (plasma [Na(+)], [Cl(-)], osmolality).

Survival of migrating salmon smolts in large rivers with and without dams

The mortality of salmon smolts during their migration out of freshwater and into the ocean has been difficult to measure. In the Columbia River, which has an extensive network of hydroelectric dams, the decline in abundance of adult salmon returning from the ocean since the late 1970s has been ascribed in large measure to the presence of the dams, although the completion of the hydropower system occurred at the same time as large-scale shifts in ocean climate, as measured by climate indices such as the Pacific Decadal Oscillation. We measured the survival of salmon smolts during their migration to sea using elements of the large-scale acoustic telemetry system, the Pacific Ocean Shelf Tracking (POST) array. Survival measurements using acoustic tags were comparable to those obtained independently using the Passive Integrated Transponder (PIT) tag system, which is operational at Columbia and Snake River dams. Because the technology underlying the POST array works in both freshwater and the ocean, it is therefore possible to extend the measurement of survival to large rivers lacking dams, such as the Fraser, and to also extend the measurement of survival to the lower Columbia River and estuary, where there are no dams. Of particular note, survival during the downstream migration of at least some endangered Columbia and Snake River Chinook and steelhead stocks appears to be as high or higher than that of the same species migrating out of the Fraser River in Canada, which lacks dams. Equally surprising, smolt survival during migration through the hydrosystem, when scaled by either the time or distance migrated, is higher than in the lower Columbia River and estuary where dams are absent. Our results raise important questions regarding the factors that are preventing the recovery of salmon stocks in the Columbia and the future health of stocks in the Fraser River.

Miniature electronic technologies now allow researchers to track a salmon's migration from its birthplace in a river's headwaters in the Rocky Mountains to the North Pacific, opening a window on the mysteries of migration and survival. Surprisingly, outward migrating salmon (smolts) have similar survival during migration down dammed and undammed rivers, challenging widely held notions about factors affecting salmon abundance. Elements of the large-scale POST (Pacific Ocean Shelf Tracking) acoustic telemetry array revealed the migrations. Although salmon smolt survival to the Pacific Ocean was comparable in both the dammed Columbia and undammed Fraser rivers, it was higher in the Columbia once distance or travel time was taken into account—and higher within the hydropower system than below the dammed section. There is not yet enough evidence to determine whether (1) the Fraser has a problem that reduces salmon survival to that of a heavily dammed river or (2) factors other than dams play a larger, unsuspected role in salmon survival. Wherever future research leads on those questions, the new fish tagging technology has demonstrated itself as a useful tool for obtaining objective scientific data with important value in a number of public policy arenas.

Electronic tagging of two species of salmon smolts reveals similar survival rates during migration down the dammed Columbia and undammed Fraser Rivers, challenging popular notions about factors affecting salmon abundance.

Computer software for pharmacy oncology services

A computer program designed to manage the informational, clinical, and data requirements for a pharmacy oncology service is described. Specialized pharmacy oncology software was developed at Rhode Island Hospital and implemented in a multihospital, integrated health system. The software performs various safety functions, supplies on-screen access to pertinent drug and patient information, manages data, and assists in the product formulation process. The programmed safeguards can be modified to meet changing requirements. The system has been in use for more than seven years and has helped detect prescribing errors and prevent preparation and administration errors. A pharmacy oncology computer program streamlines pharmacists' work and helps prevent errors in antineoplastic drug therapy.

Plasma volume and estimated liver plasma flow during hyperbaric and hyperoxic exposures in awake dogs

Five different experiments were conducted to determine if estimated liver plasma flow and/or plasma volume were changed as a result of exposure to 2.8 atmospheres absolute (ATA) while breathing 100% oxygen or 6 ATA while breathing compressed air. The experiments were designed to separate the relative roles of the ambient pressure, the partial pressure of oxygen, the time of high oxygen exposure or some combination of these factors on any observed changes. We found that time was not a factor in the changes seen. Hyperbaria resulted in a decrease in estimated liver plasma flow at all pressures greater than 1 ATA. There was an apparent increase in plasma volume at 1.3 ATA and a return towards 1 ATA values at higher pressures. Hyperoxia resulted in a decrease in estimated liver plasma flow at 975 mm Hg but not at 912 mm Hg. The flow was then increased again at 2128 mm Hg. Plasma volume decreased significantly at 912 mm Hg returned to baseline (152 mm Hg) values at 975 mm Hg and then decreased again at 1054 and 2128 mm Hg PO2.

Two methods for estimating body surface area in adult amputees

Two methods for estimating body surface area (BSA) in adult amputees were developed. BSA in sq m was determined in 42 healthy, nonamputee men and women by summing the surface areas of individual body parts obtained using geometric measurements (BSAmeas) and by an equation using height and weight (BSAcalc). Linear regression analysis was used to determine correlations between BSAmeas and BSAcalc and between BSAmeas and surface-area measurements of individual body parts (SApart). The percentages of total BSA contributed by individual body parts in each subject were determined by the ratio of SApart to BSAmeas, and these percentages were compared with the corresponding percentages for body parts using the "Rule of Nines." BSAcalc and BSAmeas were significantly correlated, as were SApart and BSAmeas. Regression analysis of SApart versus BSAmeas yielded an equation for each measured body part that allowed calculation of SApart without direct measurement. SApart expressed as a percentage of total BSA differed from the percentage of BSA used in the "Rule of Nines" by a mean of 12.4-32% depending on the body part. Two methods of estimating BSA in amputees were proposed based on deduction of the surface area of the amputated part (calculated from the regression equation for SApart or as a percentage of total BSA) from total BSAcalc in adult amputees. The two methods developed in this study for estimating BSA may be useful in determining drug dosages in adult amputees and may provide more accurate information in burn therapy. Further studies are needed to validate the clinical application of these methods.

Hemodynamic effects of 10% dextrose and of dextran 70 on hemorrhagic shock during exposure to hyperbaric air and hyperbaric hyperoxia

Six groups of six conditioned dogs each were instrumented with an electromagnetic flow-meter transducer around the pulmonary artery, and indwelling silastic cannulae in the pulmonary artery, the left ventricle, the ascending aorta, and the right atrium. After allowing a minimum of 5 d for recovery, the dogs were studied under normobaric conditions, breathing air, at 2.8 atmospheres absolute (ATA), breathing 100% oxygen (PO2 2128 mm Hg) and at 6 ATA breathing air (PO2 960 mm Hg). Baseline recordings were made at 1 ATA and repeated after arrival at depth. The dogs were hemorrhaged until the mean aortic pressure fell to 40 mm Hg. Mean aortic pressure was maintained between 40-50 mm Hg for 30 min. This required a rather constant 40 +/- 4.5 ml X kg-1 body weight of total blood removed. Three groups, one at each depth perturbation, were then given Dextran 70, the other three groups 10% dextrose. Fluids were administered at a constant rate until the mean aortic pressure rose to within 90% of its original 1 ATA baseline value. At this point, the infusion was stopped and the total amount of fluid administered was recorded. Hemodynamic parameters were measured or calculated for eight different time periods during each experiment. The amount of Dextran 70 required did not change with hyperbaric exposure but only half as much 10% dextrose was required at depth. Dextran 70 held the cardiovascular parameters constant for 30 min following administration but after 10% dextrose, cardiac output tended to decrease at 15 and 30 min posttreatment. There were no significant differences in the cardiovascular effects of hemorrhage between or among the dogs exposed to the three different environmental conditions.

Pharmacokinetics of pentobarbital under hyperbaric and hyperbaric hyperoxic conditions in the dog

High hydrostatic pressure has been shown to reverse the anesthetic effects of barbiturates. However, attempts to distinguish between two possible causes of this reversal, changes in drug disposition or changes in drug-receptor interaction, have not been reported. This study examined the possible effects of hyperbaria and hyperbaric hyperoxia on the distribution and clearance of pentobarbital in the dog. The drug was administered to six mixed-breed dogs as a 30 mg/kg i.v. bolus at 1 ATA breathing air, 6 ATA breathing air, and 2.8 ATA breathing 100% oxygen, with serial blood sampling for 12 h. Pharmacokinetic and statistical analyses showed no significant effects of hyperbaria or hyperbaric hyperoxia on the total plasma clearance, volume of distribution or elimination half-life. If pressure reversal of barbiturate anesthesia occurs at these pressures, changes in the disposition of the drug are not the causative factors.

Hemodynamic effects of lactated Ringer's solution on hemorrhagic shock during exposure to hyperbaric air and hyperbaric hyperoxia

Three groups of six dogs each were instrumented with an electromagnetic flow-meter around the pulmonary artery, and indwelling silastic cannulas in the pulmonary artery, the left ventricle, the ascending aorta and the right atrium. After allowing 5-7 d for recovery the dogs were studied under normobaric conditions, breathing air, at 2.8 atmospheres absolute (ATA) breathing 100% oxygen (PO2 approximately equal to 2128 mm Hg) and at 6 ATA breathing air (PO2 approximately equal to 960 mm Hg). Baseline recordings were made at 1 ATA and repeated after arrival at depth. The dogs were hemorrhaged until the mean aortic pressure fell to 40 mm Hg. Mean aortic pressure was maintained between 40-50 mm Hg for 30 min. Enough lactated Ringer's solution was then infused to stabilize the aortic pressure to within 90% of its original 1 ATA baseline value. Hemodynamic parameters were measured or calculated at eight different times. There were statistically significant differences in some of the measured parameters due to the effects of hemorrhage but no differences between the three groups attributable to either of the hyperbaric conditions or the effects of lactated Ringer's solution.

Salicylate pharmacokinetics in the dog at 6 ATA in air and at 2.8 ATA in 100% oxygen

Hyperbaric air and hyperbaric hyperoxia, which have been shown to decrease both liver plasma flow and plasma volume in dogs, may potentially affect the disposition of drugs whose distribution and/or elimination are dependent upon those actions. This study examined the effects of those conditions on the disposition of salicylic acid, using the dog as a model. The drug was administered to six mixed-breed dogs as a 10 mg sodium salicylate/kg i.v. bolus at 1 ATA breathing air (control), at 2.8 ATA breathing 100% O2, and at 6 ATA breathing air, followed by serial blood sampling for 8 h. Statistical analysis showed a significant increase (p less than 0.05) in salicylate clearance at 2.8 ATA compared to control with a subsequent, although not statistically significant, increase in elimination half-life. There were no significant differences between the values observed at 6 ATA and either control or 2.8 ATA. As 100% O2 at 2.8 ATA is used during hyperbaric oxygen medical therapy and during decompression, this change in disposition of this commonly used agent may have implications in man. Studies in man must be conducted, however, to determine if the same conclusions apply.

Hemodynamic effects of Dextran 40 on hemorrhagic shock during hyperbaria and hyperbaric hyperoxia

Three groups of six dogs each were instrumented with an electromagnetic flow-meter around the pulmonary artery, and indwelling silastic cannulas in the pulmonary artery, the left ventricle, the ascending aorta and the right atrium. After 7-10 d, dogs were studied under normobaric conditions, breathing air, at 2.8 atmospheres absolute (ATA) breathing 100% oxygen (PO2 approximately equal to 2128 mm Hg), and at 6 ATA breathing air (PO2 approximately equal to 960 mm Hg). Baseline recordings were made at 1 ATA and repeated after arrival at depth. The dogs were hemorrhaged until the mean aortic pressure fell to 40 mm Hg. Pressure was maintained between 40-50 mm Hg for 30 min. Enough Dextran 40 was then infused to stabilize the aortic pressure to within 90% of its original 1 ATA baseline value. Hemodynamic parameters were measured or calculated at eight different times. More than twice the amount of Dextran 40 was required at depth than at 1 ATA. There were statistically significant differences due to the effects of hemorrhage but no differences between the three groups attributable to either of the hyperbaric conditions or the effects of Dextran 40.

The "trap door" anterior capsulectomy technique for extracapsular cataract extraction with posterior chamber intraocular lens implantation in the capsular bag

A technique for performing the anterior capsulectomy in extracapsular cataract extraction is described. The "trap door" anterior capsulectomy facilitates removal of 12 o'clock cortex by retracting the superior iris. Also, the anterior capsular flap acts as a lens glide during insertion of the IOL, and as a guide for the haptic during placement of the superior loop in the superior fornix of the capsular bag.

Therapeutic effects of hyperbaric oxygen and dimethyl sulfoxide following spinal cord transections in rats

Thirty adult, male, Long-Evans hooded rats underwent spinal cord transections at the T5 vertebral level. Following surgery, animals were separated into three groups: Group I received only normal postoperative care; Group II received daily hyperbaric oxygen (HBO) treatments for 47-54 consecutive days; Group III received the same HBO treatment as Group II in addition to subcutaneous injections of dimethyl sulfoxide (DMSO) for 10 consecutive days. All animals were killed 60-70 days postlesion. The lesioned area of spinal cord was removed and prepared for light and electron microscopy. Group I animals showed typical scar reduction of cavitations, increased scarring, and more nerve fibers within the lesion. Three animals in this group exhibited coordinated hindlimb movement, with one animal showing weight-bearing ability. The lesion sit in group III animals revealed a reduction in collagen formation and a further increase in the number of nerve fibers. Six animals in Group III showed coordinated hindlimb movements; among these two displayed weight-bearing ability and sensory return.

Complex saccharide metabolism in cystic fibrosis fibroblasts

There are several reports of secretory and other abnormalities present in cultured fibroblasts from patients with cystic fibrosis (CF). We have, therefore, investigated aspects of complex saccharide synthesis and secretion by such cells compared with fibroblasts derived from heterozygous (HZ) parents and from normal (N) children. The main glycosaminoglycans produced by skin fibroblasts during in vitro culture were hyaluronic acid, heparan sulfates, and dermatan sulfate-like materials. Using double-label experiments with D-[3H]- or [14c]glucosamine and analyzing the products by ion exchange chromatography, it was shown for five CF, two HZ, and four N lines that these polysaccharides were secreted into the medium in approximately similar proportions to each other. Moreover, experiments in which three CF, nine HZ, and three N lines were grown in log phase for up to 5 days in the presence of [35S]sulfate and [3H]glucosamine indicate that, during such a period, CF fibroblasts do not secrete complex carbohydrates at rates significantly different from N or HZ cells. Neither do such cells shown an abnormal intracellular accumulation of complex carbohydrates. The latter observation was further confirmed by preparing whole cell autoradiographs during growth of six CF, two HZ, and three N lines in the presence of D-[3H]glucosamine and, subsequently, after addition of unlabeled medium.