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At least 577 records · Page 32Linked to original sources
PubMedDate not supplied

Sealing the thoracic duct with ultrasonic coagulating shears.

BACKGROUND/AIMS: Ultrasonic coagulating shears were developed as an endosurgical device that allows cutting of vessels without ligation. In this study, we obtained basic data on the feasibility of dividing and sealing the thoracic duct by using ultrasonic coagulating shears. METHODOLOGY: We obtained the thoracic duct and the left gastric artery from surgical specimens of 27 patients. After one end of each vessel was sealed using ultrasonic coagulating shears, we recorded the bursting pressure. The sealed ends of the vessels were also examined histopathologically. RESULTS: The mean bursting pressure of the thoracic duct was high enough to support the clinical use of this device, and was significantly higher than that of the left gastric artery (p<0.001). Microscopic examination of the sealed vessels showed that degenerated collagen fibers were more homogeneous and covered a significantly larger area in the thoracic duct than in the left gastric artery (p<0.001). CONCLUSIONS: The present study provides a basis for using ultrasonic coagulating shears to seal the thoracic duct and possibly lymph node dissection.

Electrocoagulation↗
PubMedDate not supplied

Seal integrity of hollow-bulb obturators.

Five techniques using various materials were evaluated for their ability to produce a watertight seal between obturator and lid. Leakage was determined by an increase in sample weight above that attributed to sorption and by visualization of water inside the clear acrylic resin samples. A watertight seal was obtained for some samples in each of the test groups. Only the two-flask technique sealed with heat-processed acrylic resin produced a watertight seal in all samples. It was determined that pressure up to 30 psi for 1 hour does not rupture a sealed hollow bulb and immersion under pressure is required to detect leakage of a bulb in a short period of time.

Dental Leakage↗
PubMed1988

Preservation of the spleen using human fibrin seal.

Because of the spleen's role in host defence and the recognition of overwhelming post-splenectomy sepsis, the current aim of treatment for splenic injuries is to preserve the spleen. A number of hemostatic agents have been used in an effort to control bleeding but have not proved satisfactory. The authors report the results of an experiment using a two-component fibrin seal on injured rabbit spleens. In female rabbits a longitudinal laceration of the entire spleen was made. After 2 1/2 minutes of continuous hemorrhaging, the spleens were either not treated (5 rabbits) or treated by splenectomy suture repair or fibrin-seal repair. Hemoglobin values were measured preoperatively and 3 days postoperatively. The greatest number of deaths within 14 days occurred in the untreated group. There was no difference in death rate between the treated groups; similarly, there was no difference in blood loss or fall in hemoglobin values. Fewer adhesions formed in the fibrin-seal group than in the others (p less than 0.02). Histopathological examination revealed a greater fibrinoblastic response in the spleens treated with fibrin seal than in the other groups. The authors believe that fibrin seal is an effective and safe hemostatic agent applicable to splenic parenchymal injuries, and that it promotes wound healing and suppresses adhesion formation.

Animals↗
PubMed1995

Microleakage of "surface-sealing" materials.

PURPOSE: To test several dental materials for their sealing properties by subjecting restored teeth to thermal cycling. MATERIALS AND METHODS: Ten teeth per group were assigned at random to six experimental and six control groups. In the experimental groups a resin composite was surface-sealed with IRM, glass ionomer, amalgam, dentin bonding agent and resin composite, experimental hybrid cement, or zinc oxide and eugenol. These six surface-seal materials were placed in bulk in the control group. After cavity preparation, restoration, cut back and application of the surface-seal material, the teeth were subjected to thermal cycling, imbedded and sectioned. A score of 0-3 was given to the amount of dye leakage observed. RESULTS: Zinc oxide and eugenol demonstrated the most leakage, whereas the resin composite system TPH had the least. The results of this in vitro study render the recommendation of zinc oxide and eugenol as a surface-seal material questionable.

Analysis of Variance↗
PubMed1994

[Corneoscleral wound healing after self-sealing cataract surgery--1. Histological findings in the early postoperative period].

We investigated histologically wound adaptation and healing after self-sealing cataract surgery in rabbits in the early postoperative period. A scleral pocket (4 mm wide, 2 mm long) and an internal corneal flap (2 mm long) were made in one eye in a series of rabbits. After phacoemulsification, a balanced salt solution was injected to self-seal the wound (self-sealing group). After the same procedures were performed in the contralateral eye, a horizontal 9-0 nylon suture was placed in the wound (suture group). On the first day after operation, the adaptation of the wound was better in the suture group than in the self-sealing group. On the fourth day, the scleral wound space was filled with fibroblastic cells and fibrin-like substance, and activated keratocytes had accumulated along the corneal wound. Although inflammatory cells collected around the suture in the suture group, there was no remarkable difference between the two groups on the seventh day. These results indicated that the adaptation of the wound in the early period was different between the self-sealing group and the suture group, and that the difference might result in different peripheral corneal curvature. This might be one of the causes of the postoperative astigmatism in the early stage.

Animals↗
PubMedDate not supplied

Influence of reinforcement design on the loss of marginal seal of provisional fixed partial dentures.

Loss of marginal cement seal, initial fracture, and stiffness of three four-unit provisional restorations were tested. Loss of marginal cement seal was monitored using strain gauges located occlusogingivally at the distal of the second molar abutment and the mesial of the first premolar abutment of a four-unit posterior fixed provisional restoration with two pontics. The provisional restorations were then placed in an Instron testing machine and loaded to initial fracture. Stiffness was calculated from the Instron recordings. The provisional designs were permachrome band-reinforced, wire-reinforced, and a nonreinforced control. Analysis showed: (1) the band-reinforced design withstood a significantly greater load before loss of cement seal (P< or =.05); (2) the band-reinforced design had a significantly higher stiffness (P< or =.05); and (3) there was no difference between the three designs for load at initial fracture. Within the same sample it was found that for both band- and wire-reinforced designs the premolar abutment lost the marginal cement seal at a significantly lower load than the molar (P< or =.05). For the control there was no significant difference for load at marginal cement seal loss between abutments.

Acrylic Resins↗
PubMed1997

Caries progression of white spot lesions sealed with an unfilled resin.

This study evaluated the artificial caries resistance provided to white spot lesions by sealing with an unfilled resin. Twenty extracted molar teeth were coated with an acid-resistant varnish (ARV), except for two 5 mm x 2 mm enamel windows (mesial and distal), and immersed for 5 weeks in an acidified gel brought to a pH of 4.2 with lactic acid. White spot lesions (not frank caries) were created in each window. The teeth were removed from the gel, rinsed and dried. One window was divided into two equal parts; one half was covered with the ARV (Group 1); the other half was not covered (Group 2). The other window was treated with 37% phosphoric acid for 20 sec, rinsed with water for 20 sec, dried and sealed with Prisma Universal Bond 2 Adhesive (Group 3). The teeth were reimmersed in the acidified gel for 40 days until frank caries was induced in Group 2. Specimens were then removed from the gel, rinsed, and sectioned occlusogingivally. Sections were polished to approximately 100 microns, imbibed in water, and analyzed using polarized light microscopy. Depth of demineralization was evaluated in the varnished, sealed and frankly carious areas. The mean (SD) lesion depths were as follows: Group 1 (under ARV) 366 microns (103 microns); Group 2 (frank caries) 746 microns (219 microns); Group 3 (under sealed area) 298 microns (111 microns). ANOVA and Student-Newman-Keuls procedure were used to compare group means. The mean depths of demineralization under the ARV (Group 1) and the unfilled resin sealant (Group 2) were significantly less than for the unprotected enamel (Group 2) (p > 0.0001). Results indicate the potential effectiveness of sealing white spot lesions with an unfilled resin to prevent further demineralization.

Analysis of Variance↗
PubMed1995

Venous structures associated with thermoregulation of phocid seal reproductive organs.

BACKGROUND: Seal reproductive systems are surrounded by thermogenic muscle and insulating blubber, suggesting elevated temperatures at the gonads and uterus. In the limbs of terrestrial mammals, cooled blood returning from superficial veins is mixed proximally with warm blood returning from deep veins. Thus, mixed cool-superficial and warm-deep venous blood from the hind limbs is returned to the central circulation. METHODS: We describe structures observed in salvaged carcasses of harbor (Phoca vitulina), gray (Haliochoerus gryphus), harp (Phoca groendlandica), hooded (Cystophora cristata), and ringed (Phoca hispida) seals. Vessels were identified by dissection of injected and uninjected material. RESULTS: In contrast to terrestrial mammals, phocid seals have anastomoses between the veins of the distal hind limb and the pelvis which allow large volumes of cool blood returning from the skin surface of the flipper to enter the gluteal, pelvic, or pudendo-epigastric veins. This provides a cool-superficial venous return that remains separate from the warm-deep venous return of the femoral veins. The cooled venous blood from the hind flippers supplies venous plexuses lining the inguinal region and the abdominal and pelvic cavities. CONCLUSIONS: Cooled blood may prevent hyperthermic insult to seal reproductive systems.

Abdomen↗
PubMed1976

Visual evoked response (VER) changes during maturation in the Weddell seal.

Visual evoked responses (VER'S) were recorded from the cortex of immature Weddel seals, 3-365 days of age. Results indicated a high degree of maturity at birth evident from the multiphasic array of waveforms and the comparatively short onset latency of the VER. At low intensities, single flashes evoked an immature secondary response. Topographical distribution of VER's were confined largely to the gyrus immediately adjacent to midline, from the posterior aspect near lambda to the vertex. Recordings from CI-744 dosed seals displayed a well-demarcated developmental sequence of VER's, contrary to VER's recorded in flaxedilized seals. Onset latency and waveform configuration changed concomitantly as a function of age. During the postnatal period from birth to weaning, VER changes were related to major behavioral events such as the seal's first encounter with swimming and diving at 2 weeks of age and weaning at 6 weeks of age.

Age Factors↗
PubMed1977

Structural correlates of forelimb function in fur seals and sea lions.

Dissections, manipulation of ligamentary preparations, analysis of limb proportions, and quantitative aspects of forelimb myology are used to correlate forelimb morphology in fur seals and sea lions (sub-family Otariinae) with previously published data as to their locomotor function (English, '76a). Comparisons to structure and function in generalized fissiped carnivores are then used to elucidate locomotor adaptations in fur seals and sea lions. Unique features of forelimb function during swimming in these pinnipeds include the amounts of abduction-adduction and rotary movements used. Modifications of the size, attachments and fasicle architecture of the muscles and the structure and range of possible movement of the joints suggest that in fur seals and sea lions these movements (1) take place about the glenohumeral (shoulder) joints, (2) that the movements are probably finely controlled, and (3) that they contribute to the generation of massive forward thrust via the cooperative activity of muscles capable of generating large amounts of force throughout the range of movement. Recovery movements occur through a similarly large range, and modifications of forelimb anatomy either to minimize or overcome water resistance are noted. The adaptive significance of these modifications is interpreted as allowing fur seals and sea lions to swim at speeds necessary to feed on the fast swimming prey presumably abundant in their adaptive zone.

Animals↗
PubMed1992

The complete mitochondrial DNA sequence of the harbor seal, Phoca vitulina.

The nucleotide sequence of the mitochondrial DNA (mtDNA) of the harbor seal, Phoca vitulina, was determined. The total length of the molecule was 16,826 bp. The organization of the coding regions of the molecule conforms with that of other mammals, but the control region is unusually long. A considerable portion of the control region is made up of short repeats with the motif GTACAC particularly frequent. The two rRNA genes and the 13 peptide-coding genes of the harbor seal, fin whale, cow, human, mouse, and rat were compared and the relationships between the different species assessed. At ordinal level the 12S rRNA gene and 7 out of the 13 peptide-coding genes yielded a congruent topological tree of the mtDNA relationship between the seal, cow, whale, human, and the rodents. In this tree the whale and the cow join first, and this clade is most closely related to the seal.

Amino Acid Sequence↗
PubMed1995

Contaminant levels in harbor seals from the northeastern United States.

The concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzofurans (PCDF), polychlorinated dibenzo-p-dioxins (PCDD), and mercury (Hg) were determined in blubber and liver tissues of harbor seals (Phoca vitulina) collected along the northeast coast of the U.S. Average PCB concentrations in seal blubber (sum of congeners) were 12.0 micrograms/g (wet weight) with a range of 7.30 to 24.3 micrograms/g in 1980 and 6.66 micrograms/g (wet weight) with a range of 2.61 to 11.3 micrograms/g in 1990-1992. Comparisons between blubber data from this study and previous work indicated that the concentration of PCBs along the northeast coast of the U.S. may have decreased over the past twenty years. The average p,p'-DDE concentrations in seal blubber were 10.9 micrograms/g (wet weight) in 1980 with a range of 6.95 to 21.9 micrograms/g and 4.12 micrograms/g (wet weight) with a range of 1.83 to 7.84 micrograms/g in 1990-1992. Only trace amounts of PCDFs and PCDDs were found in a few blubber samples; levels in most tissues were below detection (3-5 pg/g) (wet weight). Trace amounts (< 30 ng/g) of phenanthracene, anthracene, and alkylated MW-178 compounds were found in some seal samples; all other PAH compounds were below the detection level (5-15 ng/g). Toxic equivalents (TEQ) of selected coplanar and mono-ortho PCB congeners and relative toxic equivalents (RTE) (pg total TEQ/microgram total PCB) were calculated, using recently proposed dioxin toxic equivalent factors (Ahlborg et al. 1994). The TEQs ranged from 41 to 315, and the RTEs ranged from 2.25 to 16.3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1989

The eye of the hooded seal, Cystophora cristata, in air and water.

Multiple refractive state measurements were made on a male and female hooded seal (Cystophora cristata) when the eyes were exposed to air and to water. The measures, made by conventional retinoscopy and by photorefraction, show that the seals are moderately hyperopic (2-3 diopters) in water and moderately myopic (2-4 diopters) in air. No significant astigmatism was noted in either medium. The absence of refractive state variation over time suggests that an accommodative mechanism is insignificant or absent, although histological study indicates that the ciliary muscle is well developed. Photokeratoscopy, carried out on two animals with two keratoscopic instruments, show that the cornea is relatively flat (30 mm, or about one-half the diameter of the eye). Furthermore the cornea is only slightly astigmatic (less than 1 diopter). The refractive power of the external corneal surface (in air), calculated from a measurement of corneal refractive index of 1.378, amounts to only 10 or 11 diopters. As in the typical fish eye, hooded seal lenses are spherical or nearly spherical in shape (24-23 mm), and have short focal lengths (30-32 mm). Focal measures for rays at varying distances from the lens center indicate that spherical aberration is well corrected. There is no indication in this seal species, of a previously reported adaptation involving a highly astigmatic cornea which together with a slit pupil can minimize the optical effect of movement from water to air.

Air↗
PubMed1991

Polycyclic aromatic hydrocarbons in harp seals (Phoca groenlandica) from the Northwest Atlantic.

There is virtually no information available on concentrations of polycyclic aromatic hydrocarbons (PAH) in seals from any of the world's oceans. The largest harp seal population in the world is found in Canadian waters of the Northwest Atlantic. Samples of muscle tissue obtained from twenty eight harp seals ranging in age from foetuses to animals 22 years old were analyzed for total PAH and lipid content. Concentrations were determined in terms of crude oil and chrysene equivalents in line with recommendations of the International Oceanographic Commission. Overall, relatively low concentrations were found, the highest values being less than 1 ppm (microgram/g) in terms of chrysene equivalents and 4 ppm (microgram/g) in terms of petroleum hydrocarbon equivalents. The lowest concentrations were observed in fetal tissue. There was no evidence of bioaccumulation with age, the concentrations in juvenile seals (1-5 years) being higher than concentrations in older animals (6-20 years). There was also no correlation between PAH concentration and fat content. There is a possibility that the animals having elevated levels of PAH are from the Gulf of St. Lawrence herd, indicating the importance of obtaining more information on PAH levels in marine mammals and other organisms from this and similar regionally contaminated seas.

Animals↗
PubMed1986

The pineal gland is very large and active in newborn antarctic seals.

The pineal gland of newborn elephant seals and Weddell seals is larger than in adult females. The gland is considerably larger at birth in Weddell seals than in elephant seals. The former experience greater extremes of temperature. Plasma melatonin concentrations in excess of 2000 pg/ml were recorded in the first days of life, compared with 20-50 pg/ml in adults.

Animals↗
PubMed1996

Energetics of lactation in harp seals (Phoca groenlandica) from the Gulf of St. Lawrence, Canada.

This study reports the findings of an integrated, comprehensive analysis of lactation energetics in harp seals conducted using longitudinal measurements of mass, body composition and milk composition from mother-pup pairs in conjunction with water flux measurements in pups. The nursing period of harp seals is a short, intense and relatively efficient period of energy transfer from mothers to pups. The average daily milk intake for pups was 3.65 +/- 0.24 kg which is equivalent to 79.5 MJ of energy. Eighty-one per cent of the energy received in the milk was metabolisable and 66% of the energy was stored by the pups as body tissue. The field metabolic rate of pups was 3.9 +/- 0.4 time basal metabolic rate. The pups were growing at a rate of 2.2 kg per day during the nursing period. The distribution of this mass gain varied in terms of tissue composition, depending on the age of the pups, but over the whole nursing period approximately half of the tissue was stored as fat. Harp seal mothers lost an average of 3.1 kg per day during lactation which was composed of 37% water, 50% fat, 11% protein and 2% ash. Mothers spent half of their time during the lactation period actively diving and only one-third of their time on the surface of the ice. Milk compositional changes followed the normal phocid pattern with increasing fat content and decreasing water content as lactation progressed. The mean mass transfer efficiency was 73%. However, this value cannot be used without qualification because female harp seals in this study fed to varying degrees, consuming an estimated 0-4.8 kg of fish per day. Feeding does not appear to be required in order to achieve the energy requirements for lactation, given the energy stores possessed by females, and some females do fast through the entire period so feeding may be considered opportunistic in nature.

Animals↗
PubMed1992

Positional specificity of gastric hydrolysis of long-chain n-3 polyunsaturated fatty acids of seal milk triglycerides.

Long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) of marine oils are important dietary components for both infants and adults, and are incorporated into milks following maternal dietary intake. However, little is known about the hydrolysis of these PUFA from milk triglycerides (TG) by lipases in suckling young. Seals, like humans, possess gastric lipase; however, the milk lipids of seals and sea lions are almost devoid of the readily hydrolyzable medium-chain fatty acids, and are characterized by a large percentage (10-30%) of n-3 PUFA. Gastric hydrolysis of milk lipids was studied in vivo in suckling pups of three species (the California sea lion, the harp seal and the hooded seal) in order to elucidate the actions and specificity of gastric lipases on milk TG in relation to fatty acid composition and TG structure. Regardless of milk fat content (31-61% fat) or extent of gastric hydrolysis (10-56%), the same fatty acids were preferentially released in all three species, as determined by their relative enrichment in the free fatty acid (FFA) fraction. In addition to 16:1 and 18:0, these were the PUFA of 18 carbons and longer, except for 22:6n-3. Levels of 20:5n-3 were most notably enriched in FFA, at up to five times that found in the TG. Although 22:6n-3 was apparently also released from the TG (reduced in the diglyceride), it was also notably reduced in FFA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

Paucity of class I MHC gene heterogeneity between individuals in the endangered Hawaiian monk seal population.

The Hawaiian monk seal population has experienced precipitous declines in the last 50 years. In this study, we provide evidence that individuals from remaining endangered population exhibit alarming uniformity in class I major histocompatibility (MHC) genes. The peripheral blood leukocyte-derived mRNA of six captive animals rescued from a stranding incident on the French frigate shoals in the Hawaiian archipelago was used to characterize genes in the monk seal class I MHC gene family, from which techniques for genotyping the broader population were designed using degenerate primers designed for the three major established human MHC class I loci (HLA-A, HLA-B, and HLA-C), and by sequencing multiple clones, six unique full-length classical MHC class I gene transcripts were identified among the six animals, three of which were only found in single individuals. Since The low degree of sequence variation between these transcripts and the similarity of genotype between individuals provided preliminary evidence for low class I MHC variability in the population. The sequence information from the class I transcripts from these six animals was used to design several primer sets for examining the extent of MHC variability in the remaining population using a combination of polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE). Several DGGE assays, each one amplifying subtly different class I MHC gene combinations, were designed to compare exons encoding the highly polymorphic domains of the putative peptide-binding region of MHC class I. In combination, these assays failed to show interindividual variability at any of the class I MHC gene loci examined in either the six captive seals or in 80 free-ranging animals ( approximately 6.7% of the estimated population) representing all six major subpopulations of Hawaiian monk seal.

Base Sequence↗