bluuebunny/crossref_metadata_2025_split huggingface dataset:
Progressive loss of SIRT1 with cell cycle withdrawal
Authors: Sasaki Tsutomu , Maier Bernhard , Bartke Andrzej , Scrable Heidi 
Published: August 2006

SummarySir2 is an NAD+‐dependent deacetylase that regulates lifespan in yeast, worms and flies. The mammalian orthologs of Sir2 include SIRT1 in humans and mice. In this study, we analyzed the level of SIRT1 in human lung fibroblasts (IMR90) and mouse embryonic fibroblasts (MEFs) from mice with normal, accelerated, and delayed aging. SIRT1 protein, but not mRNA, decreased significantly with serial cell passage in both human and murine cells. Mouse SIRT1 decreased rapidly in prematurely senescent (p44 Tg) MEFs, remained high in MEFs with delayed senescence (Igf‐1r–/–), and was inversely correlated with senescence‐activated β‐galactosidase (SA‐βGal) activity. Reacquisition of mitotic capability following spontaneous immortalization of serially passaged wild‐type MEFs restored the level of SIRT1 to that of early passage, highly proliferative MEFs. In mouse and human fibroblasts, we found a significant positive correlation between the levels of SIRT1 and proliferating cell nuclear antigen (PCNA), a DNA processing factor expressed during S‐phase. In the animal, we found that SIRT1 decreased with age in tissues in which mitotic activity also declines, such as the thymus and testis, but not in tissues such as the brain in which there is little change in mitotic activity throughout life. Again, the decreases in SIRT1 were highly correlated with decreases in PCNA. Finally, loss of SIRT1 with age was accelerated in mice with accelerated aging but was not observed in long‐lived growth hormone‐receptor knockout mice. Thus, as mitotic activity ceases in mouse and human cells in the normal environment of the animal or in the culture dish, there is a concomitant decline in the level of SIRT1.
Progesterone‐Modulated Phosphatidylserine Externalization in Apoptosis and Activation of Jurkat Cells
Authors: Mourdjeva Milena , Popova Zlatka , Kyurkchiev Dobroslav , Kontinopoulou Katerina , Altankova Iskra , Kehayov Ivan , Kyurkchiev Stanimir 
Published: August 2006

Problem  During pregnancy the elevated levels of progesterone (Pg) have immunomodulating effects. It is important to follow‐up Pg effects on basic biological processes at cell level as apoptosis and activation which was the aim of this study.Methods of study  Jurkat cells cultured in the presence or absence of Pg were used as a model system. Apoptosis was induced by H2O2 and activation by phorbol myriastate acetate. The induced changes in the phosphatidylserine (PS) externalization and cell surface CD69 expression were followed by fluorescence‐activated cell sorter and immunofluorescence.Results  After the induction of apoptosis PS externalizes in 52.3% of Jurkat cells. Cells cultured with Pg show tendency to a decrease of PS positive cells (42%). The opposite effect is observed in activated cells – PS externalization increase from 33.8% of control cells to 40.1% of Pg‐treated cells.Conclusions  These findings would suggest that by increasing activation and decreasing apoptosis Pg could regulate local immune system during pregnancy.
In vitro evaluation of endodontic debris removal as obtained by rotary instrumentation coupled with ultrasonic irrigation
Authors: Passarinho‐Neto Jarbas Gonçalves , Marchesan Melissa Andréia , Ferreira Rafael Brandão , Silva Ricardo Gariba , Silva‐Sousa Yara Teresinha Correa , Sousa‐Neto Manoel D. 
Published: August 2006

AbstractThe cleaning capacity of rotary Ni‐Ti instrumentation using Profile GT files, coupled with irrigation energised by ultrasound, was evaluated. Thirty‐six human mandibular incisors were instrumented in vitro using the crown‐down technique with the Profile GT system to 1 mm from the anatomical apex to a size 30.04 taper file. The instrumented teeth were then divided randomly into four groups where various final irrigations were used: Group I: 100 ml of 1% NaOCl with a Luer–Lok syringe (control group); Group II, Group III and Group IV: final irrigation with 100 ml of 1% NaOCl energised by ultrasound for 1, 3 and 5 min, respectively. After biomechanical preparation, the apical thirds of the roots were submitted to histological processing and examination. The specimens were analysed at 40× magnification and the images submitted to morphometric analysis with an integration grid. anova showed a statistically significant difference (P < 0.01) between the irrigation techniques. Group I (Luer–Lok syringe) showed the highest percentage of debris (35.81 ± 4.49) and was statistically different from the other groups energised by ultrasound: Group II (27.28 ± 4.49), Group III (24.39 ± 5.72) and Group IV (18.46 ± 5.25). It was concluded that rotary instrumentation using Ni‐Ti files associated with final irrigation of 1% NaOCl energised by ultrasound leads to better debris removal from the apical third of mesio‐distally flattened root canal.
SENSORY BIOPHYSICS OF MARINE MAMMALS
Authors: Watkins William A. , Wartzok Douglas 
Published: August 2006

AbstractThe underwater existence of marine mammals has encouraged a variety of special biophysical adaptations to their environment. Their sensory and communication systems reflect the transmission properties of sea water. For example, vision is keen in spectra that penetrate water best, vocalization is broadband and used at the frequencies that appear to fit their activities best—the differences in sensory use match the intriguing variety of behavior observed for each species. To date most of the observations of animal interactions with their marine environment have dealt with sound. There has been some work on vision and studies are underway to determine animal sensitivities to hydrodynamic pressure, chemical traces and magnetic fields. The species that have been recorded to date are listed and vocalizations are generally compared. Methods for observation of sensory mechanisms are noted along with a discussion of other aspects of marine mammal biophysics including vibrissal sensation and the biophysics of movement in a fluid environment.
GROWTH LAYER GROUPS (GLGs) IN THE TEETH OF AN ADULT BELUKHA WHALE (DELPHINAPTERUS LEUCAS) OF KNOWN AGE: EVIDENCE FOR TWO ANNUAL LAYERS
Authors: Goren Arthur D. , Brodie Paul F. , Spotte Stephen , Ray G. Carleton , Kaufman H. W. , Gwinnett A. John , Sciubba James J. , Buck John D. 
Published: August 2006

AbstractGrowth layer groups (GLGs) were counted in teeth from an adult male belukha whale (Delphinapterus leucas) that had lived for 23 yr in captivity and was estimated to have been 14 mo at capture. As defined here, GLGs are repeating areas of alternating opaque (denser) and translucent (less dense) dentin or cementurn, or nodes at the dentin‐cementum interface. A GLG involves at least one change from opaque to translucent, dense to less dense or ridge to groove, but may be further subdivided by incremental growth layers or laminations. Teeth were prepared by two techniques. Thick sections (longitudinal half sections) were examined with a dissecting microscope under reflected light. Thinner cross and longitudinal sections were x‐rayed and the plates scanned with a microdensitometer. Scanning electron photomicrographs were prepared from thick sections, but SEM proved to be the least useful technique. Counts of GLGs were variable because the laminations were numerous and some surface layers had been lost from wear. Thick‐ and thinner‐section techniques gave comparable results, and approximately 40 GLGs were counted consistently. Although captive environments are less variable than natural ones, our findings are further evidence that belukhas in the wild deposit more than one—and probably two—GLGs per year.
EXTERNAL MORPHOLOGY AND PIGMENTATION OF THE VAQUITA, PHOCOENA SINUS (CETACEA: MAMMALIA)
Authors: Brownell Robert L. , Findley Lloyd T. , Vidal Omar , Robles Alejandro , Silvia Manzanilla N 
Published: August 2006

AbstractThe vaquita, Phocoena sinus, is a porpoise in the family Phocoenidae that lives only in the Gulf of California. The external appearance of P. sinus was unknown until 13 fresh specimens were recently examined. The most obvious morphological feature distinguishing P. sinus from its two congeners is the proportionately higher dorsal fin. The most striking features of the pigmentation pattern are the large black eye patches and the black upper and lower lip patches. In both areas, the pigmentation contrasts sharply with the surrounding light gray coloration. The total lengths of the specimens ranged from 70.3 cm (a neonate) to 143.5 cm (an adult female).
CORNEAL SURFACE PROPERTIES OF TWO MARINE MAMMAL SPECIES1
Authors: Dawson William W. , Schroeder J. Pete , Sharpe Scott N. 
Published: August 2006

AbstractCompared to the anterior surface of the normal human cornea, all Tursiops showed pronounced random, local curvature changes typical of old keratitis and scarring. Comparable but less severe findings apply to Zalophus. These irregularities were superimposed on the mild regular astigmatism of the spoon‐shaped Tursiops cornea (mean central power is 26.8 D, SD = 3.8, N = 82). All Zalophus corneas showed no reliable regular astigmatism (overall mean power is 21.7 D, SD = 4.4, N = 53) but exhibited a flat, circular region about 6.5 mm in diameter along the nasal aspect of the horizontal meridian. Refraction through this cornea1 region showed aerial emmetropia, which accounts for equivalent marine and aerial visual resolution in this species.
THE PHYSIOLOGICAL TRANSITION FROM FASTING TO FEEDING IN WEANED ELEPHANT SEAL PUPS
Authors: Condit Richard S. , Ortiz C. Leo 
Published: August 2006

AbstractWe studied energetics and food utilization in young elephant seals as they were first introduced to solid food following their long post‐weaning fast. Using radioactive tracer techniques, we monitored changes in body composition, protein metabolism, and metabolic rate during fasting and initial feeding. In fasting animals, fat stores supplied nearly all energetic requirements. In feeding animals, 49% of protein ingested was retained as body tissue, allowing protein mass to increase. Body fat was lost at rates comparable to rates in fasting animals and continued to fuel the bulk of metabolism. Weight loss was arrested when animals consumed 786 g/d, or 40 kcal/kg0.75/d, which was far less than their metabolic rates (63–206 kcal/kg0.75/d). Surprisingly, the young seals were able to maintain weight and store protein while energy intake was below metabolic needs. This was possible because animals gained weight as water; they retained wellhydrated proteinaceous tissue while losing poorly‐hydrated adipose tissue.
THE MICROSCOPIC AND IMMUNOHISTOLOGIC ANATOMY OF THE ENDOCRINE PANCREAS OF PYGMY AND DWARF SPERM WHALES (KOGIIDAE)
Authors: Brown Eileen Dellner , Bossart Gregory D. , Reynolds John E. 
Published: August 2006

AbstractHistologic studies of pancreatic tissues of one pygmy sperm whale, Kiogia breviceps, and one dwarf sperm whale, K. simus, demonstrated rather typical exocrine pancreatic anatomy. Peroxidase‐antiperoxidase (PAP) techniques determined that the cell composition of the islets of Langerhans resembled that of other mammals. Within islets, cells secreting insulin (B‐cells) and glucagon (A‐cells), were clearly demonstrated, but, surprisingly, isolated A‐ and B‐cells were also found among pancreatic acinar cells. PAP techniques demonstrated the presence of neuron‐specific enolase within islets, but failed to provide a sufficiently clear reaction to demonstrate the presence of somarostatin‐producing D‐cells. No positive PAP reaction for serotonin occurred.
TRACE METALS AND METHYL MERCURY: ASSOCIATIONS AND TRANSFER IN HARP SEAL (PHOCA GROENLANDICA) MOTHERS AND THEIR PUPS
Authors: Wagemann R. , Stewart R. E. A. , Lockhart W. L. , Stewart B. E. , Povoledo M. 
Published: August 2006

AbstractMilk samples from the stomachs of harp seal pups were analysed for Cu, Zn, Se, Cd and Hg, as were liver, kidney, and muscle from mother‐pup pairs. Tissues were also analysed for MeHg. Milk contained, in addition to essential trace metals, Cd and Hg (57 ng/g and 6.5 ng/g respectively).Pups had mercury in all three tissues. The percent methyl mercury in liver of pups was higher than in liver of mothers. Mercury in muscle was mostly methyl mercury in both mothers and pups. Total mercury in liver of mothers but not pups was correlated positively with selenium. Estimates of ingested mercury by pups indicated they had acquired most of their mercury during gestation.Although mothers had cadmium in liver and kidney, it was not detected in tissues of pups. Cadmium did not transfer across the placenta, while mercury did. Tissue concentrations of Cu and Zn were higher in pups than mothers. The presence of metallothionein in pup tissues was postulated.A strong positive correlation of copper and selenium between mothers and pups indicated transfer of these elements from mother to pup in direct proportion to their concentrations in maternal liver and kidney.
AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985
Authors: Gilbert James R 
Published: August 2006

AbstractThe U.S. Fish and Wildlife Service conducted a survey of the walruses in the pack ice of the Chukchi Sea between 16 September and 2 October 1985, as part of a joint effort with the Soviet Union to estimate the size of the Pacific walrus population. American observers conducted censuses from two aircraft along randomly selected north–south lines over the pack ice. The observers counted walruses within a constant viewing angle that corresponded to a total strip width of 1.38 km at an altitude of 152 m.In nine days of flying, 15,312 walruses were observed, of which 10,140 were on 5,764 km2 of census strips. Few walruses were observed east of 161°W longitude or west of 170°W longitude, hence the census effort was stratified. Walrus concentrations between 161° and 170° shifted slightly westward during the 2‐wk duration of the censuses. The differences among days in observed walrus density were due to changes in the numbers of walruses on the ice within 37 km of the ice edge. The number of observable walruses in pack ice of the eastern Chukchi Sea was estimated to be 62,177 (SD = 19,480), based on censuses conducted on 29 and 30 September and 1 October. At that time there were also at least 15,238 in Bristol Bay, Bering Sea. The Soviets counted 39,572 on the shores of the western Chukchi and Bering seas and estimated 115,531 in pack ice of the western Chukchi Sea. Summing U.S. and Soviet estimates, the total population of Pacific walruses in 1985 was 232,518. This number was comparable with earlier estimates from censuses conducted jointly by the U.S. and the Soviets. However, information on fraction hauled out, segregation, and movements is needed for more precise estimates.
GLUCOSE KINETICS IN NEONATAL ELEPHANT SEALS DURING POSTWEANING APHAGIA
Authors: Keith Edward O. , Ortiz Charles L. 
Published: August 2006

AbstractNorthern elephant seal (Mirounga angustirostris)pups undergo extended periods of terrestrial aphagia after weaning and exhibit a paradoxical fasting hyperglycemia. To investigate the details of glucose metabolism during this period, reversible and irreversible radiotracers were used to determine the body mass of glucose, and rates of glucose turnover, recycling, and oxidation in fasting seal pups. A typical 75 kg pup has a glucose mass of about 4.5 g (60 mg/kg), and a blood glucose concentration of about 174 mg/dl. Blood glucose removal rate was about 30 grams per day (17 mg/kg · h‐1), but less than 2.5% of this glucose was oxidized, contributing less than 1% of the total metabolic rate. About 20% of the glucose pool was removed from the blood per hour, yielding a turnover time in the vascular space of about five hours. Most glucose removed from the blood was returned to the blood by recycling. Such recycling may contribute to mechanisms which prolong survival during fasting, such as high rates of triacyclglycerol turnover, synthesis of new protein pools, low ketone levels, and the Cori cycle which is important during diving.
SEA OTTERS AND BENTHIC PREY COMMUNITIES IN WASHINGTON STATE
Authors: Kvitek Rikk G. , Shull David , Canestro Don , Bowlby Edward C. , Troutman Barry L. 
Published: August 2006

AbstractAn August 1987 benthic survey of otter‐free and otter‐occupied areas along the outer coast of Washington State's Olympic Peninsula confirms that this area has been as profoundly influenced by sea otters as other rocky, nearshore communities studied in California, Canada, and Alaska. Prey density, size, and biomass were found to be negatively correlated with sea otter abundance, suggesting that the re‐introduction of sea otters to this area in 1969–1970 has profoundly affected invertebrate prey abundance and distribution, particularly that of the red sea urchin, Strongylocentrotus franciscanus. Red urchin distribution appears to influence algal groups differently and in a manner consistent with current otter/urchin/kelp theory. Foliose red algal abundance was negatively related to urchin numbers and coralline crusts were positively correlated. Aerial photographs of Macrocystis integrifolia cover at Cape Alava suggest an increase since the introduction of sea otters. Given the present distribution of prey along the Olympic Peninsula coast, we conclude that as the sea otter population continues to grow, range expansion is more likely to occur to the north, which may also lead to possible conflicts with an increasing sea urchin fishery and Native American set net activity.
FLIPPERS AND PINNIPED PHYLOGENY: HAS THE PROBLEM OF CONVERGENCE BEEN OVERRATED?
Authors: Wyss André R. 
Published: August 2006

AbstractThe phylogenetic relationships of the major groups of pinnipeds are of longstanding controversy. According to prevailing paleontological opinion, pinnipeds comprise two distinct lineages of independent terrestrial carnivoran origin, A logical correlate of this view is that an enormous degree of convergence accounts for the striking resemblances of these groups.It has been generally supposed that derived similarities common to pinnipeds are independently acquired adaptations to a highly constraining environment. This has not been adequately substantiated. Moreover, considerable evidence favors a contrary conclusion. Acceptance of convergence necessarily rests on demonstration that taxa possessing characters suspected to be convergent are in fact not mutal nearest allies. In the absence of such phylogenetic information, shared derived characters are indicative of common ancestry irrespective of whether they are deemed “functionally important.” Given meager support for the proposition that pinnipeds are related to different terrestrial lineages, it is currently more judicious to regard the group's origin as monophyletic. In addition to the presumed prevalence of convergence, biogeography, the high degree of morphological divergence of phocids, and the aberrant nature of phocines have improperly contributed to acceptance of independent pinniped origins.
TRENDS IN THE INSHORE RIGHT WHALE POPULATION OFF SOUTH AFRICA, 1969–1987
Authors: Best Peter B. 
Published: August 2006

AbstractResults of annual aerial surveys of the right whale population along the southern coast of South Africa from 1971 to 1987 are analysed. About 91.5% of cows with calves and 82% of unaccompanied adults on the South African coast in spring are found within the standard survey area, with some indications that the range is expanding up the west coast. In the nearshore region, most right whales (90%) are found within 1.85 km, and all cows with calves within 0.93 km, of the coast. Within the standard survey area, specific areas of concentration can be predictably identified, both for cows with calves and unaccompanied adults. Although total counts (and counts expressed per hour flown) have increased overall, by a best estimate of 6.8% (95% CL 4.6, 9.0) per year from 1971 to 1987, some concentration areas for both classes have failed to show an increase over the same time period. Photographic flights since 1979 have permitted the movements of individually identified adult females to be monitored between successive calves. In at least one concentration area for which no overall increase between 1971 and 1987 was apparent (Mossel Bay), a large net emigration rate was found, nearly all of which involved a shift to the main nursery area to the west, off De Hoop. Reasons for the dissimilar dynamics of different concentration areas are not yet known.
RATES AND POTENTIAL CAUSES OF MORTALITY IN NORTH ATLANTIC RIGHT WHALES (EUBALAENA GLACIALIS)
Authors: Kraus Scott D. 
Published: August 2006

AbstractNorth Atlantic right whale mortality rates range from 2% to 17% over the first four years of life. Sources of mortality in this population include ship collisions, entanglements, and natural causes. A combined analysis of stranding data, entanglement records, and photographic information indicates that approximately one third of all right whale mortality is caused by human activities. Anthropogenic sources of right whale mortality may be a significant factor inhibiting growth in the North Atlantic population.
OBTAINING SKIN SAMPLES FROM LIVING SPERM WHALES
Authors: Whitehead Hal , Gordon Jonathan , Mathews Elizabeth A. , Richard Kenny R. 
Published: August 2006

AbstractSamples of sperm whale skin, useful for modern molecular analyses of DNA, can be obtained from living animals either by collecting skin sloughed naturally by the whales, or by using biopsy darts fired from crossbows or compound bows. Sloughed skin was found frequently in warm waters, and particular samples could often be linked to photographs which enabled individuals to be identified. However, sloughed skin seemed less available at higher latitudes. Two types of darts were found to collect skin but collected samples were very small (<4 mm2) and insufficient for repeated DNA fingerprinting analyses. Sperm whales always reacted to darting by “startling” and showing changes of behavior over the next few minutes, but we found no indications of longer‐term effects. In warm water studies, collection of sloughed skin seems to be generally effective, but for samples of sperm whale tissue at high latitudes modifications could probably be made to either of the darts in order to obtain larger‐sized samples.
INFRARED SENSING OF THE UNDER‐SNOW LAIRS OF THE RINGED SEAL
Authors: Kingsley Michael C. S. , Hammill Michael O. , Kelly Brendan P. 
Published: August 2006

AbstractAirborne sensing of emitted infrared (IR) was tested as a means of detecting under‐snow lairs of the ringed seal (Phoca hispida) in study areas in Resolute Passage, N.W.T. Lairs and regularly used large breathing holes could in some cases be detected by emitted IR from altitudes of up to 180 m. Lairs were more easily detected if they had thin roofs, and detectability was higher before sunrise, and under conditions of low wind, low ambient temperature and high cloud cover.