bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular basis of functional voltage‐gated K+ channel diversity in the mammalian myocardium
Authors: Nerbonne Jeanne M.
Published: August 2004

In the mammalian heart, Ca2+‐independent, depolarization‐activated potassium (K+) currents contribute importantly to shaping the waveforms of action potentials, and several distinct types of voltage‐gated K+ currents that subserve this role have been characterized. In most cardiac cells, transient outward currents, Ito,f and/or Ito,s, and several components of delayed reactivation, including IKr, IKs, IKur and IK,slow, are expressed. Nevertheless, there are species, as well as cell‐type and regional, differences in the expression patterns of these currents, and these differences are manifested as variations in action potential waveforms. A large number of voltage‐gated K+ channel pore‐forming (α) and accessory (β, minK, MiRP) subunits have been cloned from or shown to be expressed in heart, and a variety of experimental approaches are being exploited in vitro and in vivo to define the relationship(s) between these subunits and functional voltage‐gated cardiac K+ channels. Considerable progress has been made in defining these relationships recently, and it is now clear that distinct molecular entities underlie the various electrophysiologically distinct repolarizing K+ currents (i.e. Ito,f, Ito,s, IKr, IKs, IKur, IK,slow, etc.) in myocyardial cells.
Carbachol‐induced [Ca2+]i increase, but not activation of protein kinase C, stimulates exocytosis in rat parotid acini
Authors: Yoshimura Keiichi , Murakami Masataka , Segawa Akihisa
Published: August 2004

A column perfusion system was applied to rat parotid acinar cells to clarify the roles of Ca2+ and protein kinase C (PKC) in the mechanisms of carbachol (CCh)‐induced amylase secretion.

CCh evoked a biphasic response of amylase secretion with an initial rapid and large peak that reached maximum at about 10 s followed by a sustained plateau. The time profile and the dose‐response relationship paralleled with those of cytosolic free Ca2+ concentration ([Ca2+]i).

The CCh‐induced sustained response of amylase secretion maintained by Ca2+ influx into cells was ATP dependent, while the initial peak response regulated by Ca2+ released from InsP3‐sensitive stores was relatively ATP independent.

Restoration of extracellular Ca2+ during continuous stimulation with CCh in Ca2+‐free medium evoked a second rapid and large peak of amylase secretion.

Phorbol 12,13‐dibutyrate (PDBu) potentiated the CCh‐induced amylase secretion in both the initial peak and the sustained plateau without enhancing CCh‐induced [Ca2+]i changes.

PKC inhibitors such as Ro 31–8220 inhibited the potentiating effect of PDBu but only slightly reduced amylase secretion induced by CCh alone.

These results suggest that a CCh‐induced rise in [Ca2+]i triggers the final fusion and/or exocytosis of amylase secretion. CCh also has some ability to promote ATP‐dependent priming of secretory granules that, together with Ca2+ influxed into cells, contributes to the CCh‐induced sustained plateau of amylase secretion. PDBu‐induced activation of PKC promotes the priming of secretory granules, thereby enhancing the efficacy for Ca2+ to trigger fusion/exocytosis.
Evidence for control of adenosine metabolism in rat oxidative skeletal muscle by changes in pH
Authors: Cheng B. , Essackjee H. C. , Ballard H. J.
Published: August 2004

We investigated the effects of pH elevation or depression on adenosine output from buffer‐perfused rat gracilis muscle, and kinetic properties of adenosine‐forming enzymes, 5′‐nucleotidase (5′N) and non‐specific phosphatase (PT), and adenosine‐removing enzymes, adenosine kinase (AK) and adenosine deaminase (AD), in homogenates of muscle.

Depression of the perfusion buffer pH from 7.4 to 6.8, by addition of sodium acetate, reduced arterial perfusion pressure from 8.44 ± 1.44 to 7.33 ± 0.58 kPa, and increased adenosine output from 35 ± 5 to 56 ± 6 pmol min−1 (g wet wt muscle)−1 and AMP output from 1.8 ± 0.3 to 9.1 ± 3.9 pmol min−1 (g wet wt muscle)−1.

Elevation of the buffer pH to 7.8, by addition of ammonium chloride, reduced arterial perfusion pressure from 8.74 ± 0.57 to 6.96 ± 1.37 kPa, and increased adenosine output from 25 ± 5 to 47 ± 8 pmol min−1 (g wet wt muscle)−1 and AMP output from 3.7 ± 1.1 to 24.6 ± 6.8 pmol min−1 (g wet wt muscle)−1.

Activity of membrane‐bound 5′N was an order of magnitude higher than that of either cytosolic 5′N or PT: pH depression reduced the Km of 5′N, which increased its capacity to form adenosine by 10–20% for every 0.5 unit decrease in pH within the physiological range. PT was only found in the membrane fraction: its contribution to extracellular adenosine formation increased from about 5% at pH 7.0 to about 15% at pH 8.0.

Cytosolic 5′N had a low activity, which was unaffected by pH; the rate of intracellular adenosine formation was an order of magnitude lower than the rate of adenosine removal by adenosine kinase or adenosine deaminase, which were both exclusively intracellular enzymes.

We conclude that (i) adenosine is formed in the extracellular compartment of rat skeletal muscle, principally by membrane‐bound 5′N, where it is protected from enzymatic breakdown; (ii) adenosine is formed intracellularly at a very low rate, and is unlikely to leave the cell; (iii) enhanced adenosine formation at low pH is driven by an increased extracellular AMP concentration and an increased affinity of membrane‐bound 5′N for AMP; (iv) enhanced adenosine formation at high pH is driven solely by the elevated extracellular AMP concentration, since the catalytic capacity of membrane 5′N is reduced at high pH.
Protein kinase C enhances the rapidly activating delayed rectifier potassium current, IKr, through a reduction in C‐type inactivation in guinea‐pig ventricular myocytes
Authors: Heath B. M. , Terrar D. A.
Published: August 2004

The rapidly activating delayed rectifier potassium current, IKr, was studied in guinea‐pig ventricular myocytes in the presence of thiopentone, which blocks the more slowly activating component of the delayed rectifier potassium current, IKs, and using whole cell perforated patch clamp or switched voltage clamp with sharp electrodes to minimise intracellular dialysis.

Activation of protein kinase A (PKA) by isoprenaline or forskolin caused an increase in IKr tail currents. Following a 300 ms depolarising step to +20 mV, mean tail current amplitude was increased 47 ± 12% by isoprenaline, and 73 ± 13% by forskolin. No increase in IKr was observed when IKr was studied using whole cell ruptured patch clamp and there was no change in the reversal potential of IKr in the presence of isoprenaline.

The rectification of the current sensitive to E4031, a selective IKr blocker, was markedly reduced in the presence of isoprenaline and the region of negative slope was absent. This is consistent with a reduction in the inactivation of IKr and was supported by the finding that IKr, in the presence of isoprenaline, was somewhat less sensitive to block. E4031 (5 μm) blocked only 81 ± 5% of IKr in the presence of isoprenaline compared to 100 ± 0% in control.

The forskolin‐ and isoprenaline‐induced increases in IKr were inhibited by staurosporine and by the selective protein kinase C (PKC) inhibitor bisindolylmaleimide I. Direct activation of PKC by phorbol dibutyrate increased IKr tail currents by 24 ± 5%. Both the isoprenaline‐ and forskolin‐induced increases in IKr were inhibited when calcium entry was reduced by block of ICa with nifedipine or when myocytes were pre‐incubated in BAPTA‐AM.

The selective PKA inhibitor KT5720 prevented the isoprenaline‐induced increase in IKr only when the increase in ICa was also suppressed.

These data show a novel mechanism of regulation of IKr by PKC and this kinase was activated by β‐adrenoceptor stimulation. IKr seems to be enhanced through a reduction in the C‐type inactivation which underlies the rectification of the channel and such a mechanism may occur in other channels with this type of inactivation.
The effect of serum iron concentration on iron secretion into mouse milk
Authors: Zhang Peifang , Sawicki Valerie , Lewis Andy , Hanson Linda , Monks Jenifer , Neville Margaret C.
Published: August 2004

The concentration of iron in mouse milk is approximately 3 times that of the serum. Although there is clear evidence for the presence of the transferrin receptor in the rodent mammary gland, the precise mechanisms of iron transfer into milk are not known.

Milk iron was linearly related to the serum iron:transferrin ratio in lactating mice whose serum iron ranged from 8 to 66 μm.

Increasing the iron binding capacity of the milk by 340 μm by targeting the lactoferrin transgene to the mammary gland did not alter the relation between milk iron and the serum iron:transferrin ratio.

The steady‐state distribution ratio of 125I‐transferrin between plasma and milk was about 0.2, indicating that transcytosed transferrin contributed a maximum of 6% of the milk iron.

Fluorescently labelled transferrin incubated with the in situ gland localized mainly near the basal surface of the mammary alveolar cells.

These experiments provide evidence that the initial and rate‐limiting step in the transfer of iron into milk is binding to a basal transferrin receptor.

A theoretical model of the relation between milk and serum iron suggests that the affinity of apotransferrin for the basal recycling system may be higher than observed in many other cell types.
Quantal currents at single‐site central synapses
Authors: Auger C. , Marty A.
Published: August 2004

The mode of operation of synaptic transmission has been primarily worked out at the vertebrate neuromuscular junction, thus providing a framework for the interpretation of studies at central synapses. However, differences have been found between the two systems, and a coherent model is still lacking for central synapses. Research in this area revolves around several questions. (1) Is the variability of quantal amplitudes determined pre‐ or postsynaptically? (2) What is the occupancy of postsynaptic receptors following the release of a synaptic vesicle? And (3) does multivesicular release occur at single release sites following one presynaptic action potential? To answer these questions, it is essential to investigate synaptic processes at the level of single release sites. This is technically difficult because of the complex morphology and small dimensions of central synapses. Nevertheless significant advances have been made in the past few years.
Polymorphic microsatellite markers for the Florida scrub lizard (Sceloporus woodi)
Authors: ERNST J. A. , BRANCH L. C. , CLARK A. M. , HOKIT D. G.
Published: August 2004

The Florida scrub lizard (Sceloporus woodi) is one of a suite of species restricted to Florida scrub, a threatened ecosystem. We characterized eight microsatellite loci from scrub lizards based on screening of 75–91 individuals per locus. Polymorphism was high (8–20 alleles per locus). Observed and expected heterozygosities ranged from 0.32–0.83 and 0.77–0.91, respectively. These markers will be useful for population‐level analyses and can contribute to a genetic foundation for conservation strategies for this endemic species.
Microsatellite loci for Dawson's burrowing bee (Amegilla dawsoni) and their cross‐utility in other Amegilla species
Authors: BEVERIDGE MAXINE , SIMMONS LEIGH W.
Published: August 2004

Microsatellite loci were isolated from Dawson's burrowing bee, Amegilla dawsoni, a species endemic to Western Australia. Twelve polymorphic loci were found with an observed number of alleles ranging from two to 24 and observed heterozygosities between 0.17 and 0.85. These 12 loci were tested for amplification in three additional species of Amegilla. The loci will be used for sex determination and the examination of mating frequency in this species.
Characterization of microsatellite loci for five members of the minnow family Cyprinidae found in the Sacramento–San Joaquin Delta and its tributaries
Authors: BAERWALD MELINDA R. , MAY BERNIE
Published: August 2004

Two microsatellite‐enriched libraries [(CAGA)n, (TAGA)n] were constructed using pooled DNA from three cyprinid species native to the Sacramento–San Joaquin Delta of California: Sacramento splittail (Pogonichthys macrolepidotus); Sacramento pikeminnow (Ptychocheilus grandis); and tui chub (Siphateles bicolor). Primers were designed for 105 loci and tested for levels of polymorphism in five cyprinid species found in the Delta: Sacramento splittail, Sacramento pikeminnow, tui chub, hitch (Lavinia exilicauda), and Sacramento blackfish (Orthodon microlepidotus). Fifty‐one loci were polymorphic for at least one species and 31 loci were polymorphic for multiple species. The number of polymorphic loci per species ranged from 16 to 26.
Microsatellite DNA markers for the study of horseshoe crab (Limulus polyphemus) population structure
Authors: KING TIM L. , EACKLES MICHAEL S.
Published: August 2004

Twenty‐two microsatellite DNA loci were identified and characterized for horseshoe crabs (Limulus polyphemus) collected from two Atlantic coast and one Gulf of Mexico site. These markers revealed a high degree of genetic diversity (8–35 alleles per locus), heterozygosity (25.0% to 100.0%), and allelic heterogeneity (69.8% of comparisons). Considerable regional differentiation was observed as genetic distances (chord) ranged between 0.25 and 0.45, and all FST values (0.014–0.092) were significant. These preliminary findings are consistent with patterns of regional differentiation observed using allozyme variation and contradictory to findings of limited gene flow reported for sequence variation at the mitochondrial DNA COI region.
Characterization of microsatellite markers for plant‐ants of the genus Crematogaster subgenus Decacrema
Authors: FELDHAAR HEIKE , FIALA BRIGITTE , GADAU JÜRGEN
Published: August 2004

We present primer sequences for five polymorphic microsatellite loci in ants of the genus Crematogaster subgenus Decacrema that live in obligate symbiosis with host plants of the euphorb genus Macaranga. Microsatellite loci were isolated with a highly efficient method of enrichment. The number of alleles ranged from 10 to 18 for Crematogaster morphospecies 2, for which these markers were developed, with an observed heterozygosity ranging from 0.6578 to 0.9474. The markers were designed for the study of the population as well as of the social structure of colonies.
New set of microsatellite loci isolated in apricot
Authors: MESSINA R. , LAIN O. , MARRAZZO M. T. , CIPRIANI G. , TESTOLIN R.
Published: August 2004

We report 99 simple sequence repeats (SSRs) newly isolated from an apricot (Prunus armeniaca L.) genomic library enriched for AG/CT repeats. Twenty SSRs were screened for their polymorphism in 16 apricot cultivars. The number of alleles ranged from two to nine, whereas the expected heterozygosity (HE) ranged from 0.26 to 0.82. The same SSRs showed also an appreciable transportability across different Prunus species, such as peach, nectarine, almond, European plum, Japanese plum, sweet cherry and sour cherry, with 20% of primers giving successful amplifications in all Prunus species assayed. None gave amplification in apple.
Isolation of microsatellite loci in the freshwater goby, Rhinogobius sp. (Gobiidae)
Authors: OHARA K. , TAKAHASHI D. , TAKAGI M.
Published: August 2004

The Rhinogobius species complex (Pisces: Gobiidae) includes great variation in colour, morphology and ecological form. In particular, R. sp. OR (Orange type) exhibits some of the greatest colour variation among the species complex, although the genetic relationships among the variations in this fish remain unclear. Thirteen microsatellite loci were identified from R. sp. OR, and all loci were polymorphic with two to 17 alleles per locus. Observed heterozygosity ranged from 0.1 to 0.9, while the expected heterozygosity ranged from 0.19 to 0.96. Multiplex polymerase chain reaction reaction (PCR) were optimized. All loci except Rhi‐5 conform to Hardy–Weinberg equilibrium (P > 0.05).
Twenty polymorphic microsatellites in two of North Africa's most threatened ungulates: Gazella dorcas and Ammotragus lervia (Bovidae; Artiodactyla)
Authors: BEJA‐PEREIRA ALBANO , ZEYL EVE , OURAGH LAHOUSINE , NAGASH HAMID , FERRAND NUNO , TABERLET PIERRE , LUIKART GORDON
Published: August 2004

During the last century, North African ungulate species have suffered from habitat loss and over‐hunting. Gazella dorcas (Antilopidae subfamily) and Ammotragus lervia (Caprinae subfamily) are among the ungulates that have suffered most. To help to protect these species, conservation programs and population genetics studies are being implemented. Here, we tested 30 published microsatellite primer‐pairs from Bovids (cattle, sheep and goat) on eight individuals from each species. From the 30 loci tested, 20 amplified well and showed moderate allelic richness (3.75 and 4.65 mean number of alleles per species, respectively, for G. dorcas and A. lervia), and moderatly high heterozygosity (0.53 and 0.63 per species, respectively). These 20 polymorphic markers will facilitate conservation and genetic studies in these two species, and promise to be widely useful across divergent ungulate taxa.
Eight highly polymorphic microsatellite loci for the Australian gecko Heteronotia binoei
Authors: STRASBURG JARED L.
Published: August 2004

Eight highly polymorphic dinucleotide microsatellite loci were developed for the Bynoe's gecko, Heteronotia binoei. Across the species as a whole, expected heterozygosities for the loci range from 0.59 to 0.92, with observed numbers of alleles ranging from 13 to 27. All eight loci successfully amplify in each of the three most widespread sexual chromosome races of Heteronotia binoei, and with the exception of one locus in one race all are polymorphic. All eight loci also amplify in hybrid parthenogenetic Bynoe's geckos, in several other sexual chromosome races, and in related Heteronotia species.
A multiplex panel of microsatellite markers for widespread sub‐Saharan rodents of the genus Mastomys
Authors: GALAN M. , VAN HOOFT W. F. , LEGRAND D. , BERTHIER K. , LOISEAU A. , GRANJON L. , COSSON J. F.
Published: August 2004

We isolated and characterized 12 polymorphic microsatellite loci in the sub‐Saharan rodent Mastomys huberti. We tested cross‐species amplification of all these loci in three closely related Mastomys species: M. coucha, M. erythroleucus and M. natalensis. Multiplex panels comprising 11 loci were developed and their application to a set of individuals in each species allowed clear and easy characterization of allele sizes. Statistics from 31 M. huberti coming from one locality in Mali showed no deviation from Hardy–Weinberg equilibrium except for one locus, and no significant linkage disequilibria between loci.
Isolation and characterization of microsatellite loci in Tripterygion delaisi
Authors: CARRERAS‐CARBONELL J. , MACPHERSON E. , PASCUAL M.
Published: August 2004

We isolated 49 microsatellite loci from a genomic library of Tripterygion delaisi×anthosoma enriched for CA and GA repeats. Ten loci were screened in 30 individuals with high numbers of alleles per locus (averaging 15.5 ± 2.86) and observed heterozygosity (averaging 0.765 ± 0.052). No deviations from Hardy–Weinberg expectations were detected. These highly polymorphic markers will be useful in determining the spatial patterns of genetic diversity between and within subspecies of Tripterygion delaisi.
Characterization and isolation of DNA microsatellite primers in the cardinalfish (Apogon doederleini)
Authors: MILLER‐SIMS VANESSA , ATEMA JELLE , KINGSFORD MICHAEL J. , GERLACH GABRIELE
Published: August 2004

Proper management of reef areas depends greatly on understanding the degree of dispersal of each species involved. The larvae of most reef fishes disperse from the natal reef before or soon after hatching and return to the reef environment after a pre‐settlement stage of several days to weeks. We characterized eight polymorphic microsatellite loci for the cardinal fish Apogon doederleini to study the spatial scale of connectivity of populations of different reefs of the Great Barrier Reef, Australia.
Eleven polymorphic microsatellite loci in a coral reef fish, Pterapogon kauderni
Authors: HOFFMAN ERIC A. , ARGUELLO J. ROMAN , KOLM NICLAS , BERGLUND ANDERS , JONES ADAM G.
Published: August 2004

We describe the isolation and characterization of 11 polymorphic tetranucleotide microsatellite loci from a male mouthbrooding coral reef fish, the Banggai cardinalfish Pterapogon kauderni. In a sample of 37 fish from a natural population, polymorphism at these loci ranged from two to 15 alleles, with expected heterozygosities ranging from 0.107 to 0.928, enabling high‐resolution genetic studies of this coral reef fish.
Isolation and characterization of microsatellite loci from Chiasmia assimilis (Warren, 1899) (Lepidoptera: Geometridae)
Authors: WARDILL T. J. , SCOTT K. D. , GRAHAM G. C. , ZALUCKI M. P.
Published: August 2004

Twelve microsatellite loci are presented for the biological control agent Chiasmia assimilis (Warren, 1899). These microsatellite loci were obtained through the construction of an enriched library, overcoming previous reported difficulties with obtaining microsatellites from other Lepidoptera due to the low frequency of microsatellites in their genomes.
Microsatellite loci from the Caribbean Fruit Fly, Anastrepha suspensa (Diptera: Tephritidae)
Authors: FRITZ ANN H. , SCHABLE NANCY
Published: August 2004

The lack of polymorphic genetic markers suitable for genotyping sperm, eggs, and all life stages of the important agricultural pest, Anastrepha suspensa, have prevented detailed genetic studies of its breeding system, reproductive dynamics, and population dynamics. We describe polymerase chain reaction (PCR) primers and reaction conditions for amplifying nine polymorphic microsatellite DNA loci isolated from this species. The PCR primers were tested on four to five individuals each collected from five geographically distant locations in Florida. Heterozygosity values and the number of alleles per locus varied from 0.11 to 0.89, and from two to 12, respectively.
Microsatellites isolated in almond from an AC‐repeat enriched library
Authors: TESTOLIN R. , MESSINA R. , LAIN O. , MARRAZZO M. T. , HUANG W.‐G. , CIPRIANI G.
Published: August 2004

We have isolated 44 SSRs from an AC‐enriched genomic library from almond (Prunus amygdalus Batsch.). Twenty SSRs were screened for their polymorphism in 16 cultivars and for their transportability in seven different Prunus species (peach, nectarine, apricot, European plum, Japanese plum, sweet cherry, sour cherry) and in apple. The expected heterozygosity ranged from 0.62 to 0.89. About 30% of primers gave successful amplification in seven different Prunus species; in two cases amplifications were obtained also in apple.
Isolation of seven polymorphic microsatellite loci, using an enrichment protocol, in the high Andean Asteraceous Chaetanthera pusilla
Authors: TILL‐BOTTRAUD I. , GIRAUD T. , FOURNIER E. , TORRES C. , VAUTRIN D. , SOLIGNAC M. , GENTON B. , ARROYO M. T. K.
Published: August 2004

We report the development of seven microsatellite markers in the high Andean Asteraceae Chaetanthera pusilla. An enrichment protocol was used to isolate microsatellite loci, and polymorphism was explored with samples from two natural populations collected in the high Andes at La Parva and Valle Nevado (Chile). We found a high level of polymorphism, heterozygote deficiency and strong differentiation among populations. Four of the seven loci successfully cross‐amplified in other Chaetanthera species.
Seven polymorphic microsatellite loci for paternity assessment in the mallard (Anas platyrhynchos)
Authors: DENK A. G. , GAUTSCHI B. , CARTER K. , KEMPENAERS B.
Published: August 2004

We describe seven polymorphic microsatellite loci for the mallard (Anas platyrhynchos). The microsatellites presented here are highly polymorphic, with on average 12 alleles in a sample of 15 presumably unrelated individuals. Therefore, they enable detailed parentage analysis in wild mallard populations, and can be used to answer many intriguing questions in behavioural ecology and evolutionary biology.
Characterization of microsatellite multiplexes for population genetic studies of bluehead wrasse (Thalassoma bifasciatum, Pisces: Labridae)
Authors: WILLIAMS D. A. , PURCELL J. , COWEN R. K. , HUGHES C. R.
Published: August 2004

Bluehead wrasse (Thalassoma bifasciatum) are common coral reef fish found throughout the Caribbean. Larval duration in the plankton is relatively long for this species, which raises the possibility of long‐distance transport by ocean currents. Several nongenetic studies suggest, however, that most recruits were spawned locally. Determination of the relative importance of local recruitment vs. immigration for recruitment is needed for the effective management of populations and establishment of marine reserves. We characterized seven new polymorphic microsatellite loci for bluehead wrasse and optimized them into PCR multiplexes with three previously published loci to determine the level of dispersal between populations.
Development and polymorphism of simple sequence repeat DNA markers for the evergreen shrub Ilex leucoclada M.
Authors: TORIMARU T. , TANI N. , TSUMURA Y. , HIRAOKA K. , TOMARU N.
Published: August 2004

We have developed 13 microsatellite loci from an enrichment library of genomic DNA in the evergreen shrub Ilex leucoclada. One hundred and eighty‐nine out of 432 clones were found to contain microsatellite repeats. Primer pairs were designed for 92 of these clones according to their sequence data. Thirteen of these primer pairs revealed polymorphism among 36 individuals sampled from 12 populations. Three to 27 alleles per locus were detected, and the expected heterozygosity ranged from 0.133 to 0.971. Because these 13 microsatellite markers showed high degrees of genetic variation, they should be useful tools for studying population and ecological genetics of I. leucoclada.
Microsatellite loci in the European bee‐eater, Merops apiaster
Authors: DASMAHAPATRA K. K. , LESSELLS C. M. , MATEMAN A. C. , AMOS W.
Published: August 2004

Twelve polymorphic microsatellite markers have been developed for the European bee‐eater, Merops apiaster (Coraciiformes: Meropidae). Screening of eight individuals at these loci showed that the average allelic diversity was 5.8, with a range of two to 11 alleles per locus. The loci reported here will provide insight into the levels of extra‐pair parentage, kin selection and dispersal in this species, which has co‐operative breeding and nests in large colonies.
Metamorphic evolution of the Georgetown Inlier, northeast Queensland, Australia; evidence for an accreted Palaeoproterozoic terrane?
Authors: Boger S. D. , Hansen D.
Published: August 2004

Mineral textures, coupled with thermodynamic modelling in the MnO–Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O (MnNCKFMASH) model system, of mid‐amphibolite facies metapelites from the Georgetown Inlier, northeast Australia, point to the recording of two separate and unrelated metamorphic events. The first occurred contemporaneously with Palaeo‐ to Mesoproterozoic orogenesis and involved heating and burial to temperatures and pressures of approximately 600–650 °C and 6.0–7.0 kbar. Textural evidence for the up‐temperature (and pressure) prograde part of this path is inferred from the inclusion of garnet in biotite and staurolite. The second metamorphic event resulted in a low‐pressure thermal overprint that is equated with the advective addition of heat to the terrane via the emplacement of the Forsayth Batholith (c. 1550 Ma). This event is inferred from subsequent growth of andalusite and randomly orientated fibrolitic sillimanite after garnet, biotite and staurolite. This two stage metamorphic evolution, when coupled with a number of other distinct geological characteristics, suggests that the Georgetown Inlier is dissimilar to the other Australian Palaeoproterozoic terranes with which it is commonly correlated.
Periodic evaluation of the occlusal vertical dimension of maxillary dentures from the wax trial denture through 48 hours after polymerization
Authors: Swords Robert L. , Latta George H. , Wicks Russell A. , Huget Eugene F.
Published: August 2004

Purpose This study measured the effects of commercial resin type on maxillary complete dentures with monoplane teeth by periodically comparing the occlusal vertical dimension of the polymerized dentures with the baseline, wax trial denture fiducial measurements.

Materials and Methods Commercially available compression‐molded, injection‐molded, and fluid poly(methyl methacrylate) resins, as well as one compression‐molded methyl acrylate ester copolymer, were evaluated. Ten dentures were fabricated from each resin using monoplane teeth. The occlusal vertical dimension at the articulator pin was measured at the wax denture stage for each specimen, and changes in occlusal vertical dimension for each denture were evaluated at a simulated laboratory remount, and at 0, 3, 6, 24, and 48 hours after a simulated clinical remount. Repeated measures analysis of variance (α= 0.05) and post hoc one‐way factorial analysis of variance and Scheffe's F‐Tests for each resin group were performed using ranks of raw data.

Results Changes in the maxillary denture mean occlusal vertical dimensions were recognized throughout the evaluation periods compared with the wax‐denture baseline, and time was a significant influence on displacement (p= .0001). Only the compression‐molded poly(methyl methacrylate) dentures exhibited a mean laboratory remount occlusal vertical dimension that was significantly greater than the mean wax denture measurement, and all resin systems exhibited occlusal error that was significantly less than the laboratory remount measurements at 48 hours. At 48 hours, all resin groups exhibited mean occlusal vertical dimension changes that were less than 1 mm compared with the wax denture. Only compression‐molded poly(methyl methacrylate) dentures exhibited a mean 48‐hour clinical remount measurement that was statistically similar to the mean wax denture occlusal vertical dimension.

Conclusions Individual maxillary dentures from all resin types and at all intervals exhibited dimensional change. At the last evaluation period, the compression‐molded poly(methyl methacrylate) showed no change in mean occlusal vertical dimension from baseline, whereas remaining groups exhibited occlusal vertical dimensions significantly less than baseline.
Stresses within porcelain veneers and the composite lute using different preparation designs
Authors: Seymour Kevin G. , Cherukara George P. , Samarawickrama Dayananda Y.D.
Published: August 2004

Purpose The purpose of this study was to investigate compressive and tensile stresses in porcelain and composite at the labial marginal region of porcelain veneer restorations using chamfer, shoulder, or knife‐edge labial margin designs with labial window or incisal overlap incisal preparation designs.

Methods Porcelain veneer models were constructed and loaded with (1) a 200‐N, 45° palatal load to simulate functional loading, and (2) a horizontal labial loading of 200 N to mimic trauma. Maximum tensile and compressive stresses were recorded within the labial marginal region of both porcelain and composite lute.

Results Under the 45° palatal load, stresses within the palatal marginal porcelain were chiefly compressive, and stresses for the knife‐edge designs as much as 42% less than for shoulder designs. Incisal overlap preparations were generally associated with less compressive stress within both porcelain and composite than the window preparation. When a labial load was applied, tensile stresses were as much as 25 times greater for the chamfer and shoulder designs compared with the knife‐edge design. Labial loading also resulted in an increase in tensile stresses within the composite lute, and stresses were again lowest within the knife‐edge margin design.

Conclusions Under the limitations of this study, using the incisal overlap preparation, porcelain veneers with knife‐edge labial margins could better sustain occlusal loading without fracture.
Influence of curing method, sealer, and water storage on the hardness of a soft lining material over time
Authors: Polyzois Gregory L. , Frangou Mary J.
Published: August 2004

Purpose The purpose of this study was to determine the hardness of plasticized acrylic resin soft lining materials over time when curing procedures were modified and when surface sealers were either used or omitted.

Materials and Methods A chairside plasticized acrylic resin material and a heat processed plasticized resin material were made into disks 40 mm in diameter and 10 mm in thickness. Materials were cured by processing at an elevated temperature or at mouth temperature. Five samples were used with each processing method. Half of all samples were treated with a surface sealer, whereas the other samples received no surface treatment. After processing, the samples were immersed in 37°C water for a total time of 1 year. Specimens were tested to determine hardness on a monthly basis. Testing was accomplished using a Shore A durometer.

Results Hardness testing showed differences relative to material and to time after processing. The heat‐processed plasticized resin material showed significantly higher Shore A hardness values than the chairside over the entire experimental period (p < .01). Increased hardness was seen for all materials over time, but this was more pronounced with plasticized acrylic resin in which the hardness increased from 28.4% to 115.8% depending on processing method and surface treatment. Surface treatment showed significant softening only when the samples were cured at simulated mouth temperature (p < .05).

Conclusions Processing method and time after processing have an effect on surface hardness of the tested materials, but neither of these effects is as profound as the initial choice of material.
The effect of amitriptyline on pain intensity and perception of stress in bruxers
Authors: Raigrodski Ariel J. , Mohamed Shawky E. , Gardiner Diana M.
Published: August 2004

Purpose The purpose of this clinical pilot study was to evaluate the effect of a tricyclic antidepressant, amitriptyline, on pain‐intensity level and level of stress in bruxers.

Materials and Methods In a randomized, double‐blind, crossover experimental design, 10 subjects received active (amitriptyline 25 mg/night) and inactive (placebo 25 mg/night) medication, over a period of 4 weeks.

Results The administration of amitriptyline for 4 weeks did not significantly (p > .05) reduce pain intensity. However, it significantly (p < .05) reduced the level of stress perception.

Conclusion The results of this limited study do not support the administration of small doses of amitriptyline over a period of 4 weeks for the management of pain resulting from sleep bruxism. However, the results support the administration of small doses of amitriptyline for the management of the perception of stress levels associated with sleep bruxism.
Accuracy and pourability of gypsum preweighed packages
Authors: Wee Alvin G. , Monaghan Peter , Johnston William M.
Published: August 2004

Purpose The purpose of this study was to determine the amount of gypsum provided by the manufacturers in their preweighed packages and to determine the amount of gypsum dispensed from the packages as a function of the method used.

Materials and Methods One hundred twenty unopened packages from 8 manufacturers were weighed. Ten packages from each manufacturer were opened with the contents completely removed by tapping the packages, and the contents were weighed (thorough method). The other 5 packages from each manufacturer were opened, quickly poured, and the contents weighed (quick method). All packages were then slit open on all sides and completely cleaned. The cleaned packages were then weighed. Calculations were made to determine (1) the amount of gypsum that was “supplied” by the manufacturer and (2) the amount removed from the packages using the “quick” and “thorough” methods. The raw data was normalized to percentage of stated weight. A Welch analysis of variance was used to evaluate the heteroscedastic data at a 95% confidence level. Thereafter, a post hoc Student t test was used to determine if the percentages of stated weight for (1) supplied, (2) thorough, and (3) quick were significantly different from 100%.

Results A statistically significant difference was found for the amount of gypsum supplied by the manufacturers (p < .001) and the amount of material removed from the packages via the 2 different methods used (p < .001). Seven of the 8 manufacturers' preweighed packages were remarkably close to their stated weight for amounts “supplied” and the “thorough” method. High standard deviations from the mean were found for the “quick” method of gypsum removal.

Conclusion Within the limits of this study, results indicate that the use of a “thorough” method to remove gypsum from preweighed packages was important. Ideally, gypsum supplied in preweighed packages should be weighed initially to ensure an optimal water/powder ratio.
Discoloration of a titanium alloy removable partial denture: A clinical report
Authors: Sutton Alan J. , Rogers Paul M.
Published: August 2004

With recent advances in dental technology, titanium is currently used for fabrication of crowns, fixed partial dentures, implant frameworks, and removable partial denture frameworks. The use of titanium‐aluminum‐vanadium (Ti‐6Al‐4V) alloy assumes that it imparts similar anti‐corrosion characteristics to the commercially pure titanium. This clinical report describes a patient who experienced discoloration of a Ti‐6Al‐4V alloy removable partial denture.
Conversion of an implant radiographic template into a surgical template
Authors: Sykaras Nikitas , Woody Ronald D.
Published: August 2004

A method is presented for converting a radiographic template into a surgical template using the information acquired from the analysis of tomograms. Necessary changes of the implant position and angulation are transferred to the indexed and sectioned cast. Realignment of the initial template with the correct position allows its modification into a surgical template.
Laboratory strength of glass ionomer and zinc phosphate cements
Authors: Piwowarczyk Andree , Ottl Peter , Lauer Hans‐Christoph
Published: August 2004

Purpose The present in vitro study examined 3 mechanical properties, namely compressive, flexural, and diametral tensile strength, of various commercially available cements and core materials as a function of time after mixing.

Materials and Methods The examined materials were 2 cermet cements (Ketac Silver [ESPE, Seefeld, Germany] and Chelon Silver [ESPE]), 1 metal‐reinforced glass ionomer cement (Miracle Mix [GC Dental Industrial Corp, Tokyo, Japan]), 2 conventional glass ionomer cements (Ketac Bond [ESPE] and Ketac Cem [ESPE]), 1 standard cure zinc phosphate cement (Harvard Cement [Richter and Hoffmann, Berlin, Germany]), and 1 zinc phosphate cement with the addition of 30% silver amalgam alloy powder (Harvard Cement 70% with Dispersalloy 30% [Richter and Hoffmann/Johnson and Johnson, East Windsor, NJ]). Properties were measured using a universal testing machine at 15 minutes, 1 hour, and 24 hours after first mixing.

Results Compressive strengths varied widely between the 3 times of measurement from 5.8 ± 6.6 MPa for Ketac Cem to 144.3 ± 10.2 MPa for Ketac Silver. Twenty‐four hours after mixing, the Bonferroni test showed significant (p≤ .01) differences between Ketac Silver and all other materials tested. Diametral tensile strengths ranged widely from 4.4 ± 0.9 MPa for Ketac Cem to 11.5 ± 2.2 MPa for Chelon Silver. At 15 minutes, 1 hour, and 24 hours after first mixing, the analysis of variance did not show any significant differences between Ketac Silver, Chelon Silver, and Miracle Mix. The 3‐point flexural strength of Ketac Silver showed, at 15 minutes with 13.5 ± 3.9 MPa and at 24 hours with 27.2 ± 7.4 MPa, the highest values.

Conclusions Setting time influences the mechanical properties of the materials tested in this study. Ketac Silver, a glass ionomer cement reinforced with sintered glass‐silver particles, showed the highest mechanical properties of the examined materials.
Effect of polyaramid fiber reinforcement on the strength of 3 denture base polymethyl methacrylate resins
Authors: Foo Hao , Lindquist Terry J. , Aquilino Steven A. , Schneider Robert L. , Williamson Derrick L. , Boyer Daniel B.
Published: August 2004

Purpose The interactive effects of synthetic polyaramid reinforcement fibers on the transverse strength of intact and repaired heat‐polymerized denture base acrylic resins were investigated.

Materials and Methods Three polymethylmethacrylate (PMMA) polymers were tested: Acron MC (GC International Corp, Scottsdale, AZ), Lucitone 199 (Dentsply International Inc, York, PA), and Microlon (The Hygienic Corp, Akron, OH). With each polymer, there were 2 controls and 4 experimental groups (n = 9 per group). The treatment groups were intact heat‐polymerized PMMA control, PMMA with unreinforced repair, PMMA with polyaramid reinforced repair, intact polyaramid reinforced heat‐polymerized PMMA control, polyaramid reinforced PMMA with unreinforced repair, and polyaramid reinforced PMMA with polyaramid reinforced repair. The transverse fracture strengths of the samples were measured with a 3‐point bending test on a Zwick Universal Testing Machine (Zwick of America, Inc, East Windsor, CT).

Results The highest mean strength at fracture was recorded with intact polyaramid reinforced heat‐polymerized PMMA controls for all resins. Analysis of variance showed significant differences in transverse strength (p < .05) by experimental group, by material, and by interaction of group and material. Tukey HSD (honestly significant difference) Multiple Comparisons Test (α= 0.05) showed that intact polyaramid reinforced heat‐polymerized PMMA controls were significantly stronger than intact heat‐polymerized PMMA controls and all the other treatment groups. Use of polyaramid reinforcement in repair of unreinforced PMMA or polyaramid reinforced PMMA did not result in significantly increased transverse strength.

Conclusions Polyaramid reinforcement significantly increased the transverse strength of intact heat‐polymerized PMMA. Polyaramid fibers did not significantly increase strength to reinforce PMMA repairs.
The effect of dental implant spacing on peri‐implant bone using the rabbit (oryctolagus cuniculus) tibia model
Authors: Hatley C. Lee , Cameron Stephen M. , Cuenin Michael F. , Parker M. Harry , Thompson Stevan H. , Harvey Stephen B.
Published: August 2004

Purpose This study investigated the effects of implant proximity on inter‐implant bone height, density, and osseointegration using digital radiography and histology.

Materials and Methods After a feasibility study, a total of 80 endosteal implants were placed in 20 New Zealand White Rabbit tibias. With the aid of a surgical jig, four 8.5‐mm implants were placed in the medial aspect of the tibial crest at inter‐implant distances of approximately 1, 1.5, and 3 mm. Standardized digital radiographs using a paralleling device were made immediately after placement of implants. Implants were allowed to osseointegrate for 90 days. After this healing period, the animals were sacrificed, and the standardized radiographs were repeated. The tibias were harvested, processed, and invested in epoxy. Sagittal sections were made from each specimen for histologic evaluation. The initial and postmortem digital radiographs were evaluated for inter‐implant distances, vertical bone height changes over time and between implant pairs, and bone density changes over time and between implant pairs using a computer image analysis program and computer statistics program.

Results The actual inter‐implant distances were consistent in a range of 0.2 mm. Bone height increased significantly from presurgical levels at all 3 locations (p < .0005). Repeated measures analysis of variance comparing change in bone height at the 3 implant pair distances showed significant differences among the 3 (p= .002). Paired t tests showed that the amount of bone growth at the 1‐mm separation site was significantly greater than the 1.5‐mm site (p= .026) and the 3‐mm site (p= .001), whereas bone growth at the 1.5‐ and 3‐mm sites did not show significant differences (p= .162). A repeated measures analysis of variance comparing change in bone density showed no significant differences (p > .05) among the 3 inter‐implant distances for either the 8‐mm position (approximately crestal bone height) or the 6‐mm position (approximately 2 mm subcrestal).

Conclusions Within the limits of this study, it seems placing implants closely together does not adversely affect bone height or density. Conversely, it seems that placing implants closer together may increase bone growth.
Effect of package weight on the total amount of die stone used annually in a dental school
Authors: Price Richard B. , Gerrow Jack D. , Bannerman Ronald A.
Published: August 2004

Purpose This study compared the total amount of Type IV dental stone (die stone) used annually by dental students when they were supplied with either 70‐g or 140‐g preweighed packages of die stone.

Materials and Methods In September 1994, all the bulk containers of die stone were removed from the student dental clinic and laboratories and replaced by 70‐g preweighed packages of die stone (Silky‐Rock; Whip Mix, Louisville, KY). At the end of August 1998, all 70‐g packages of die stone were removed from the student dental clinic and laboratories. The average annual number of 70‐g packages of preweighed die stone used by the students from 1994 to 1998 was calculated. From September 1998 to the end of August 1999, only 140‐g preweighed packages of die stone (Silky‐Rock) were supplied to the students. The number of the 140‐g packages of preweighed die stone and total weight used by students during this period were calculated and compared with the average annual number of 70‐g preweighed packages of die stone used during the 1994–1998 period.

Results From September 1994 to August 1998, the students used an annual average of 4060 ± SD 250 of the 70‐g packages (284.2 ± 17.5 kg per annum). From September 1998 to August 1999, the students used 3360 of the 140‐g packages (470.4 kg).

Conclusions Although the students used in total 700 fewer of the 140‐g die stone packages per annum than the annual average number of 70‐g packages, they used 186.2 kg (65.5%) more die stone when supplied with the 140‐g packages.
The dental student as a technician: Preclinical and clinical laboratory programs in fixed prosthodontics
Authors: Petropoulos Vicki C. , Weintraub Annette , Weintraub Gerald S.
Published: August 2004

Purpose A 2‐part survey of United States dental schools was conducted. The first part of the survey was published in 1998 and determined the curricular structure, techniques taught, and materials used in predoctoral fixed prosthodontics courses. The purpose of the second part of the survey was to ascertain the delegation of laboratory procedures in preclinical and clinical fixed prosthodontic programs.

Materials and Methods The survey was mailed to the course directors of predoctoral fixed prosthodontic programs at 53 US dental schools. Of these, 42 schools returned the completed survey, resulting in a response rate of 79%.

Results Results from this survey show that certain laboratory procedures in preclinical and clinical fixed prosthodontics are completed by dental laboratories (either in‐house or commercially available laboratories).

Conclusions For the preclinical programs of fixed prosthodontics, there is more student involvement in the completion of laboratory procedures in the dental schools surveyed. In clinical fixed prosthodontic programs, there is a high emphasis on patient care and less on laboratory techniques that can be delegated to laboratory technicians.