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At least 127 records · Page 7Linked to original sources
PubMed2006

Hematology and serum chemistry of harp (Phoca groenlandica) and hooded seals (Cystophora cristata) during the breeding season, in the Gulf of St. Lawrence, Canada.

Standard hematologic and serum chemistry parameters were determined from 28 harp seals (Phoca groenlandica) and 20 hooded seals (Cystophora cristata) sampled from 6 March 2001 to 13 March 2001 during the breeding season. Whole blood was collected immediately postmortem from harp seal mother-pup pairs and from six hooded seal pups, and from live-captured adult hooded seals and three hooded seal pups; blood was analyzed within 24 hr at a local human hospital. A certified veterinary laboratory validated subsamples of whole blood and analyzed all serum chemistry parameters. Significant interlaboratory differences in mean values of packed cell volume (PCV) and mean cell volume (MCV) were found. Significant differences were found between samples from the five seal groups (adult male hooded seals, lactating female hooded seals, unweaned hooded seal pups; lactating female harp seals, and unweaned harp seal pups) for hematology and most serum chemistry parameters. In general, age-class influenced mean values of PCV, hemoglobin (HB), red blood cell (RBC) counts, MCV, mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC), and nucleated red blood cell (NRBC) counts per 100 leucocytes, but most age-related variations were species specific. Harp seal pups had significantly lower mean values of HB, PCV, MCH, and MCHC than did other seal groups, and significantly lower mean RBC counts than did hooded seal pups. Mean NRBC counts per 100 leukocytes were more than three times higher in harp seal pups than in hooded seal pups, but this difference was not statistically significant. Mean MCV were significantly lower in harp and hooded seal pups compared to those of adult harp and hooded seals. Differences in hemograms between pup species were likely because of the precocious development of hooded seal pups, which are weaned within 4 days, compared to 12 days for harp seal pups. Among adult seal groups, male hooded seals had significantly higher mean values of PCV and HB than did female harp and hooded seals, and significantly higher mean RBC counts than did adult female hooded seals. Among adult females, mean values of MCH and MCHC were statistically higher in hooded seals than in harp seals. Adult female harp and hooded seals did not differ significantly in other RBC parameters and mean leukocyte counts. Mean values of glucose, blood urea nitrogen, total bilirubin, alanine aminotransferase (ALT), alkaline phosphatase (ALP), total protein, and albumin showed species-specific variations between adults and pups. Except for ALP, few significant differences in mean enzyme activities of aspartate aminotransferase (AST), ALT, creatine kinase and gamma-glutamyltransferase were found between seal groups. Mean concentrations of electrolytes (calcium, phosphorus, sodium, potassium, chloride, magnesium, and total carbon dioxide) varied with age class, but variations in potassium and magnesium were species specific. Harp seal pups had significantly higher mean phosphorus and potassium levels compared to other seal groups.

Age Factors↗
PubMed1998

Effects of buoyancy on the diving behavior of northern elephant seals.

Marine mammals experience radical seasonal changes in body composition, which would be expected to affect their buoyancy in the water. The aim of this study was to examine the relationship between such changes in buoyancy and diving behavior in northern elephant seals Mirounga angustirostris. This was achieved by modifying the buoyancy of 13 juvenile elephant seals translocated from Año Nuevo State Reserve, CA, USA, and released at various sites in Monterey Bay, CA, USA. The buoyancy of each seal was calculated and was increased or decreased using syntactic foam or lead weights, and their diving behavior was recorded as they returned to Año Nuevo. The seals were divided into three groups: increased buoyancy (B+), reduced buoyancy (B-) and control seals (Bc). Mean descent rates were 0.77+/-0.3 ms-1 for the B+ seals, 0.82+/-0.2 ms-1 for the control seals and 0.87+/-0.3 ms-1 for the B- seals, and were significantly different. Mean ascent rates for the three treatments were 0.82+/-0.3 ms-1 for the B+ seals, 0.86+/-0.3 ms-1 for the control seals and 0.82+/-0.3 ms-1 for the B- seals. All the B+ seals ascended faster than they descended, while four of the five B- seals descended faster than they ascended. There was a significant negative correlation between buoyancy and descent rate, with less buoyant seals descending faster than more buoyant seals. There was, however, no correlation between ascent rate and buoyancy. This suggests that seals may use negative buoyancy to drift passively during descent, but that all seals may swim continuously during ascent. There was a significant correlation between buoyancy and the drift descent rate of C-type drift dives, including upwards drift in the most buoyant seal. Buoyancy was not correlated with diving depth, trip duration, dive duration or surface-interval duration. This study demonstrates that buoyancy plays a significant role in shaping diving behavior in northern elephant seals and that elephant seals may adjust their behavior to suit their buoyancy, rather than adjusting their buoyancy to suit a dive. This study also validated the truncated cones method of calculating body composition in this species by comparing it with body composition determined using tritium dilution.

Adipose Tissue↗
PubMed2006

[Clinical evaluation of three different materials for fissure sealing after 12 months].

AIM: Fissure sealing is a preventive and therapeutic procedure by which the occlusal surface of the fissure system of the teeth is closed with sealing materials for prevention and therapy of initial caries. The fissures of the teeth treated with sealing materials become physiologically clean spots, with no possibility for the developement of caries lesion. The aim of the study was to clinically compare three different fissure sealing materials after one year of use. METHODS: The study included 73 subjects, 29 (39.7%) male, and 44 (60.3%) female, aged 7-21 years. Sealing was carried out on 150 healthy permenant molars with three different sealing materials divided into three groups: Teethmate F1 (Kuraray) in 48 teeth, Helioseal Clear Chroma (Vivadent) in 52 teeth, and Tetric Flow (Vivadent) in 50 teeth. In each subject, at least two different sealing materials were used. On analysis of the degree of retention and occurrence of secondary caries lesion, modified criteria described by Kilpatrick et al. (1996) were used: 0=no loss, 1=loss of 1/3 of the seal, 2=loss of 2/3 of the seal, 3=complete loss of the seal (more than 2/3 of the material). The criteria for evaluation of the occurrence of secondary caries were: 0=no caries, 1=caries. RESULTS: After 12 months, complete retention of the Teethmate F1 material was 77.1%, of Helioseal Clear Chroma 76.9%, and of Tetric Flow 84%. There is no statistically significant difference in retention among the sealing materials after 12 months. Tetric Flow showed a better appearance of retention, although not statistically significant (p=0.287). Out of 150 sealed teeth, at 12 months caries was found in only 3 teeth: 2 in the group sealed with Teethmate F1 and one in the group sealed with Helioseal Clear Chroma. In the group sealed with Tetric Flow, no caries was recorded at 12 months. CONCLUSION: Comparison of the degree of retention showed flowable composite as a sealing material to yield better results than the classic sealing materials, although the difference was not statistically demonstrated. The low incidence of caries in the fissure system between sealed teeth indicated a good preventive action of the sealing materials. Because of the great supply of flowable composites on the market, differing in the content and consistency, and a great number of various enamel-dentin adhesive systems, there is a need of additional long-term research to determine their clinical justifiability.

Adolescent↗
PubMed2004

Accumulation of dietary organochlorines and vitamins in Baltic seals.

We studied the accumulation of polychlorinated biphenyls (PCBs), 1,1,1.trichloro-2,2-bis[p-chlorophenyl]ethane (DDT) and its metabolites, and vitamins A and E in the top levels of the Baltic Sea food web. The investigation focused on the transfer of contaminants and vitamins to the ringed seal (Phoca hispida baltica) and the grey seal (Halichoerus grypus) from their main prey species. The trophic level of the seals was investigated using stable isotopes of nitrogen and the results indicated that both species of Baltic seal feed at approximately the same level. PCBs accumulated to a greater extent in the grey seal than in the ringed seal. Biomagnification factors for DDT compounds were similar for both species of Baltic seal (85-140). Differences in observed DDT levels were due to different prey selection by the two species, while differences in PCB levels indicated a species-specific metabolic system. There was a clearly greater accumulation of DDT compounds than of PCBs in both species of seal. The supply of dietary vitamin A was normally above the recommended level in all the seal populations studied. Low levels of hepatic vitamin A in the Baltic seals could therefore indicate the toxic effects of a high level of persistent organic pollutants on vitamin A dynamics, at least in the ringed seal. In the grey seals, low hepatic vitamin A levels could also be explained by lower levels of dietary vitamin A, compared to the reference grey seals, as it is not known if seals can store unlimited amounts of vitamin A. The greater uptake of vitamin E by Baltic seals, compared to seals in the reference areas, demonstrated by elevated levels of vitamin E in the blubber, could be a response to oxidative stress caused by the high contaminant load. These results further support our previous hypothesis that the toxic effects of environmental contaminants could be causing the observed divergence in vitamin levels between the Baltic seals and the reference seal populations.

Adipose Tissue↗
PubMed1994

Mercury and selenium in arctic and coastal seals off the coast of Norway.

Mercury and selenium concentrations (wet weight) have been determined in samples of liver, kidney and brain of grey seal (Halichoerus grypus), harbour seal (Phoca vitulina), harp seal (Phoca groenlandica) and ringed seal (Phoca hispida) caught along the Norwegian coast, 114 individuals in all. Significant differences have been found in mercury contamination between the 4 species caught in the same coastal area, Jarfjord, located at the north-east of the Norwegian coast close to the Russian border. Very low hepatic mercury levels were found in the arctic species, ringed and harp seals, ranging from 0.20 to 0.67 and 0.04 to 1.0 microg g(-1), respectively, while in the coastal seal species the concentrations were 10 to 40 times higher. The corresponding ranges were 0.7 to 48.3 microg g(-1) in grey seals and 0.2 to 19.0 microg g(-1) in harbour seals. The median values were 13.5 and 0.7 microg g(-1), respectively. The highest levels were found in grey seals, indicating that particularly the stock frequenting the waters of the north-east coast of Norway and north-west coast of Russia had received a substantial mercury exposure. Fifty-five percent of these grey seals from Jarfjord had hepatic mercury levels above 10 microg g(-1) and 21% had levels above 20 microg g(-1). By a one-way analysis of covariance, sex and age were found to explain 28 and 30%, respectively, of the total variability in the mercury concentration in grey seal from Jarfjord. Significant differences in mercury concentrations were also found between stocks of harbour seals caught at different sites along the Norwegian coast, and decreasing concentration from the south to the north-east coast of Norway was revealed. The renal mercury levels in the arctic seals ranged from 0.08 to 0.45 microg g(-1), and about five times higher levels were found in grey seals and harbour seals. The mercury levels in the brain ranged from the detection level (0.01 microg g(-1)) to about 0.1 microg g(-1). The hepatic selenium levels in the arctic seal species ranged from 0.8 to 3.7 microg g(-1). The corresponding ranges in grey seals and harbour seals were 1.0 to 23.3 microg g(-1). The renal selenium levels were lower, and the levels in the brain were below the detection level (0.01 microg g(-1)). The mercury/selenium ratio was close to unity for mercury concentrations greater than 15 microg g(-1), and a nonlinear, concave relationship was found between the ratio of the hepatic mol concentrations of mercury and selenium and the hepatic mol concentrations of mercury.

Journal Article↗