[Single file endodontic treatment: a new era?].

Root canal shaping is one of the key stages of endodontic treatment, when performed properly, it is a predictive factor for the outcome of the treatment. It is critical for an adequate disinfection, which is more effective at the completion of a proper shaping procedure. The introduction of NiTi instruments into endodontic greatly improved the root canal shaping and decreased the time required for a full mechanical preparation. Over the last 2 decades, numerous attempts have been made to further improve the procedure with a wide range of rotary NiTi endodontic file systems. All these systems require several subsequent files. Recently, three different concepts of single-file systems have been introduced: 1. The single file reciprocating working motion: it consists of a reciprocating counterclockwise and a clockwise motion. This reciprocal motion reduces torsional loads thus, allows safer instrumentation with less working time. 2. Single-file instrumentation using full 360 degrees rotational movement to be used in a full clockwise rotation. Some of these files also have an Anti Breakage Control (ABC) which protects from catastrophic procedural malfunction by unwinding of these file before breakage. 3. The Self-Adjusting File (SAF) which is a thin-walled, pointed cylinder, hollow nickel-titanium endodontic file that is elastically compressible into a root canal that has been previously negotiated using a #20 hand file and can widened inside it, facilitating removal of debris and dentin from the canal wall. The file conforms to the canal shape and permits irrigant flow through the file. The SAF works in a combined vibrating and partial rotational motions, and circumferentially simultaneously enlarging and irrigating the canal. The objectives of these new approaches is to reduce the working time and cost and improve safety of the shaping procedure, and suggest to have a lower procedural errors incidents. Few studies, conducted in the recent years, using these new instruments demonstrated an excellent shaping and centering ability of these new systems. They produce smooth tapered canal preparations with reproducible results, even when performed by less experienced practitioners. As mentioned above, these new techniques appeared to be promising, but further fundamental clinical and laboratory studies are needed to confirm their abilities.

Telescope alignment from sparsely sampled wavefront measurements over pupil subapertures.

We present a simple formalism that has proven useful in on-axis alignment of two-element telescopes when wavefront information is available from only a limited region (here two noncontiguous subapertures) of the pupil. Misalignments cause predictable full-aperture aberrations, which in turn cause predictable tip/tilt modes in the subapertures. For the most useful case in which secondary mirror tilts are independently constrained by optical monitoring, the four subaperture tip/tilt modes provide enough information to solve for the state of misalignment uniquely. A practically important and intuitively appealing simplification of this inversion occurs if the tip/tilts of the two subapertures are first transformed into a new basis consisting of differential and common-mode tilts in each of the x and y directions. Then the matrices interpreting subaperture modes as full-aperture aberrations and those in turn as mechanical misalignments become diagonal, so the mechanical adjustment required to align each degree of freedom is just a constant sensitivity multiplying one of the measured differential or common-mode tilt basis modes. Knowing that this simplification occurs allows rapid empirical calibration of sensitivities in the lab and then deterministic alignment, simply and transparently, with no need for ray tracing to model the optical effects of the adjustments at each step of the alignment.

Achieving low cleft palate fistula rates: surgical results and techniques.

OBJECTIVES: To prospectively evaluate and reduce fistula rate after primary cleft palate repair in an academic setting. METHODS: After noting an institutional palate fistula rate of 35.8%, when a majority of palatoplasties were performed using the Furlow double-opposing Z-plasty, the decision was made to re-evaluate the surgical techniques used for palate repair. As part of our re-evaluation, Furlow and von Langenbeck repairs were limited to clefts less than 8 mm in width. Wider clefts were repaired early in the series with Veau-Wardill-Kilner and later with Bardach two-flap palatoplasties. Half of each palate repair was performed by the residents. SETTING: Multidisciplinary follow-up was obtained at the University of North Carolina Craniofacial Center. RESULTS: A palate fistula was noted in 2 (1.6%) out of 126 cleft palate repairs (both fistulas were located at the anterior hard palate). A split uvula was identified in 2 of 59 patients where the status of the uvula was reported (3.4%). CONCLUSION: This study summarizes one of the lowest overall fistula rates reported in the literature. In a tertiary-care academic setting, plastic surgery residents can actively contribute to palatoplasty with a very low fistula rate. Technical keys to achieving low fistula rate include skeletonization of the vascular pedicle for medialization of the mucoperiosteal flaps, aggressive posterior repositioning of the levator muscle, and meticulous two-layer mattress-suture closure. We recommend Furlow repair for narrower clefts (less than 8 mm wide at the posterior border of the hard palate) and the Bardach two-flap palatoplasty for wider clefts.

Phylogeographic history of the New Zealand stick insect Niveaphasma annulata (Phasmatodea) estimated from mitochondrial and nuclear loci.

We have assessed the utility of a single-copy nuclear locus and mitochondrial DNA (mtDNA) in a phylogeographic study of the New Zealand stick insect Niveaphasma annulata (Hutton). We amplified sequences from the mitochondrial cytochrome oxidase subunit I (COI) gene and the single-copy nuclear gene elongation factor-1alpha (EF1alpha) from 97 individuals. Allelic phase at the EF1alpha locus was determined using Denaturing Gradient Gel Electrophoresis. Phylogenetic analyses showed broad congruence between the geographic distribution of three major COI clades and EF1alpha alleles, which suggested that the phylogenetic patterns reflect population history rather than lineage sorting. However, the geographic boundaries of these clades were not always in exact agreement between the two loci. Our data indicate that Niveaphasma annulata was most likely separated into a number of refugia during Pleistocene glacial advances. Subsequent to glacial retreat these refugial populations have expanded and now form a number of zones of secondary contact. We contrast these patterns with those observed from other New Zealand taxa. Our study offers compelling evidence for the use of nuclear genes alongside mtDNA for future phylogeographic studies.

High yield expression of biologically active recombinant full length human tuftelin protein in baculovirus-infected insect cells.

Tuftelin is an acidic protein expressed at very early stages of mouse odontogenesis. It was suggested to play a role during epithelial-mesenchymal interactions, and later, when enamel formation commences, to be involved in enamel mineralization. Tuftelin was also detected in several normal soft tissues of different origins and some of their corresponding cancerous tissues. Tuftelin is expressed in low quantities, and undergoes degradation in the enamel extracellular matrix. To investigate the structure and function of tuftelin, the full length recombinant human tuftelin protein was produced. The full length human tuftelin cDNA was cloned using Gateway recombination into the Bac-to-Bac system compatible transfer vector pDest10. This vector adds a hexahistidine tag to the N-terminus of the expressed protein, enabling one-step affinity purification on nickel column. The recombinant human tuftelin protein was transposed into the bacmid and expressed in Spodoptera frugiperda (Sf9) insect cells. The yield of the purified, his-tagged recombinant full length human Tuftelin (rHTuft+) was 5-8 mg/L culture. rHTuft+ was characterized by SDS-PAGE, Western blot, ESI-TOF spectrometry, restriction mapping and MS/MS sequencing. The availability of the purified, full length recombinant human tuftelin protein opened up the possibility to investigate novel functions of tuftelin. Application of rHTuft+ agarose beads onto embryonic mouse mandibular explants caused changes in the surrounding epithelial cells, including morphology, orientation and spatial organization. Further studies using DiI labeling, revealed that rHTuft+, placed on the tooth germ region, brought about recruitment of adjacent embryonic mesenchymal cells. These findings support the hypothesis that tuftelin plays an important role during embryogenesis.

PartCrafter: find, generate and analyze BioParts.

The field of Synthetic Biology is both practically and philosophically reliant on the idea of BioParts-concrete DNA sequences meant to represent discrete functionalities. While there are a number of software tools which allow users to design complex DNA sequences by stitching together BioParts or genetic features into genetic devices, there is a lack of tools assisting Synthetic Biologists in finding BioParts and in generating new ones. In practice, researchers often find BioParts in an ad hoc way. We present PartCrafter, a tool which extracts and aggregates genomic feature data in order to facilitate the search for new BioParts with specific functionalities. PartCrafter can also turn a genomic feature into a BioPart by packaging it according to any manufacturing standard, codon optimizing it for a new host, and removing forbidden sites. PartCrafter is available at partcrafter.com.

Phylogeography of two New Zealand lizards: McCann's skink (Oligosoma maccanni) and the brown skink (O. zelandicum).

The New Zealand skink fauna has proven to be an ideal taxonomic group in which to examine the impact of climatic and geological processes on the evolution of the New Zealand biota since the Pliocene. Here we examine the phylogeography of McCann's skink (Oligosoma maccanni) in order to gain insight into the relative contribution of Pliocene and Pleistocene processes on patterns of genetic structure in the South Island biota, and investigate the phylogeography of the brown skink (O. zelandicum) to examine whether Cook Strait landbridges facilitated geneflow between the North and South Islands in the late-Pleistocene. We obtained mitochondrial DNA sequence data (ND2 and ND4; 1282bp) from across the range of both species. We examined the phylogeographic patterns evident in each species using Neighbour-Joining, Maximum Likelihood and Bayesian methods. We found substantial phylogeographic structure within O. maccanni, with seven distinct clades identified. Divergences among clades are estimated to have occurred during the Pliocene. Populations in the Otago/Southland region (south of the Waitaki River valley) formed a well-supported lineage within O. maccanni. A substantial genetic break was evident between populations in east and west Otago, either side of the Nevis-Cardrona fault system, while north-south genetic breaks were evident within the Canterbury region. Within-clade divergences in O. maccanni appear to have occurred during the mid- to late-Pleistocene. Shimodaira-Hasegawa topology tests indicated that the 'Garston' skink is not genetically distinct from O. maccanni. There was only relatively minor phylogeographic structure within O. zelandicum, with divergences among populations occurring during the mid- to late-Pleistocene. Our genetic data supports a single colonisation of the North Island by O. zelandicum from the South Island, with the estimated timing of this event (0.46mya) consistent with the initial formation of Cook Strait.

The human tuftelin gene: cloning and characterization.

Tuftelin has been suggested to play an important role during the development and mineralization of enamel. We isolated the full-length human tuftelin cDNA using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (5' RACE and 3' RACE) methods. Sequence analysis of the tuftelin cDNA revealed an open reading frame of 1170 bp encoding a 390 amino acid protein with a molecular mass of 44.3 kDa and an isoelectric point of 5.7. The human tuftelin protein shares 89 and 88% amino acid sequence identity with the bovine and mouse tuftelin, respectively. It contains a coiled-coil region, recently reported to be involved with tuftelin self-assembly and with the interaction of tuftelin with TIP39 (a novel tuftelin interacting protein). Detailed DNA analysis of the cloned genomic DNA revealed that the human tuftelin gene contains 13 exons and is larger than 26 kb. Two alternatively spliced tuftelin mRNA transcripts have now been identified in the human tooth bud, one lacking exon 2, and the other lacking exon 2 and exon 3. Primer extension analysis, corroborated by RT-PCR and DNA sequencing, revealed multiple transcription initiation sites. The cloned 1.6 kb promoter region contained several GC boxes and several transcription factor binding sites such as those for activator protein 1 and stimulatory protein 1. Our blast search of the human and mouse expressed sequence tag data bases, as well as our RT-PCR and DNA sequencing results, and a previous study using Northern blot analysis revealed that tuftelin cDNA sequences are also expressed in normal and cancerous non-mineralizing soft tissues, suggesting that tuftelin has a universal function. We have now identified and characterized different alternatively spliced mouse tuftelin mRNAs in several non-mineralizing tissues. These results provide an important baseline for future understanding of the biological role of tuftelin.

Ion-molecule reactions and collision-activated dissociation of C4H 4 (+.) isomers: A case study in the use of the MS (3) capabilities of a pentaquadrupole mass spectrometer.

Isomeric C4H 4 (+.) radical cations vinylacetylene (a), butatriene (b), methylene cyclopropene (c), and the nonaromatic cyclobutadiene (d), generated, respectively, from the neutral precursors 3-butyn-1-ol (1), 1,4-dichloro-2-butyne (2), benzene (3), and 7,8-benzotricyclo [4.2.2.0(2,5)]deca-3,7,9-triene (4), undergo diagnostically different ion-molecule reactions with allene, isoprene, furan, and thiophene. It is speculated that adducts are generated by [2 + 2] cycloadditions with the first reagent and [4 + 2] Dials-Alder cycloadditions with isoprene, furan, and thiophene. The initially formed cycloaddition adducts fragment rapidly, isomerize, or undergo further addition of neutral reagent to yield a complex set of products. With a pentaquadrupole mass spectrometer, MS(3) experiments that employ three stages of ion mass analysis are used to help elucidate the ion-molecule reactions and to distinguish the isomeric C(4)H 4 (+.) ions. Among these experiments, the reaction intermediate spectrum reveals the nature of the intermediates connecting the reactant to a selected product while the sequential product spectrum provides mechanistic and structural information on the adducts and other ion-molecule products. The unique combination of ion-molecule reactions with collision-activated dissociation employed here provides valuable information on the chemistry of ionized cyclobutadiene, including its proclivity to undergo [2 + 2] and [4 + 2] cyc1oadditions.

Polar [4+2(+)] diels-alder cycloaddition to nitrilium and immonium ions in the gas phase: Applications of multiple stage mass spectrometry in a pentaquadrupole instrument.

Multiple stage MS(2) and MS(3) mass spectrometric experiments, performed using a pentaquadrupole instrument, are employed to explore the gas-phase ion-molecule chemistry of several nitrilium [R-C≡N(+)-H (1), R-C≡N(+)-CH3 (2), and H-C≡N(+)-C2H5 (3)] as well as immonium ions RR(1)C=N(+)R(2)R(3) (4) with the neutral diene isoprene. Polar [4+2(+)] Diels-Alder cycloaddition is observed for nitrilium ions when the energy gap between the lowest unoccupied molecular orbital (LUMO) of the ion and the highest occupied molecular orbital (HOMO) of the isoprene is small and the competing proton transfer reaction is endothermic. Thus, C-protonated methyl isonitrile H-C≡N(+)-CH3 (2a) and its higher homolog H-C≡N(+)-C2H5 (3a) form abundant [4+2(+)] cycloadducts with isoprene, but several protonated nitriles 1 do not; instead they show exothermic proton transfer as the main ion-molecule reaction. Replacement of the methyne hydrogen in 2a by a methyl, ethyl, or phenyl group (2b-d) raises the LUMO-HOMO gap, which greatly decreases the total yield of ion-molecule products and precludes cycloaddition. On the other hand, the electron-withdrawing acetyl and bromine substituents in 2e and 2f substantially lower the LUMO energy of the ions and cycloaddition reaction occurs readily. The simplest member of the immonium ion series, CH2=NH 2 (+) (4a), reacts readily by cycloaddition, whereas alkyl substitution on either the carbon or nitrogen (4b-f) dramatically lowers the overall reactivity, which substantially decreases or even precludes cycloaddition. In strong contrast, the N-phenyl (4g) and N-acetyl (4h) ions and the N-vinyl-substituted immonium ion, N-protonated 2-aza-butadiene (4i), react extensively with isoprene, mainly by [4+2(+)] cycloaddition. However, the isomeric C-vinyl-substituted ion (4j) displays only modest reactivity in both the proton-transfer and the cycloaddition channels.Collision-induced dissociation (CID) of the cycloadducts performed by on-line MS(3) experiments demonstrates that they are covalently bound and supports their assignments as cycloaddition products. Retro Diels-Alder fragmentation is a major process for cycloadducts of both the immonium and the nitrilium ions, but other fragmentation processes also are observed. The cycloadduct of 4a with butadiene displays CID fragmentation identical to that of the authentic ion produced by protonation of 1,2,3,6-tetrahydropyridine, which thus strengthens the [4+2(+)] cycloaddition proposal. AM1 calculations also support the formation of the [4+2(+)] cycloadducts, which are shown in several cases to be much more stable than the products of simple addition, that is, the ring-open isomers.

Confinement and dynamics of laser-produced plasma expanding across a transverse magnetic field.

The dynamics and confinement of laser-created plumes expanding across a transverse magnetic field have been investigated. 1.06 microm, 8 ns pulses from a neodymium-doped yttrium aluminum garnet laser were used to create an aluminum plasma which was allowed to expand across a 0.64 T magnetic field. Fast photography, emission spectroscopy, and time of flight spectroscopy were used as diagnostic tools. Changes in plume structure and dynamics, enhanced emission and ionization, and velocity enhancement were observed in the presence of the magnetic field. Photographic studies showed that the plume is not fully stopped and diffuses across the field. The temperature of the plume was found to increase due to Joule heating and adiabatic compression. The time of flight studies showed that all of the species are slowed down significantly. A multiple peak temporal distribution was observed for neutral species.

Microbiological status of Australian sheep meat.

Two studies were undertaken to determine the microbiological status of sheep carcass meat and frozen, bulk-packed sheep meat produced in Australia. Samples were collected from 470 sheep carcasses and 415 cartons of frozen sheep trimmings over a period of approximately 12 months. Samples were collected from plants processing sheep carcasses for domestic or export markets. On carcasses, where bacterial counts were obtained, the mean of the log10 aerobic plate count (APC) was 3.92/cm2, the geometric mean of the most probable number (MPN) per square centimeter of Escherichia coli (biotype I) was 23, and the geometric mean of the coliform count was 38 MPN per cm2. A high percentage (75%) of samples was positive for E. coli (biotype I), 81% were positive for coliforms, 5.74% were positive for Salmonella spp., and 1.29% were positive for Campylobacter. Bacterial counts were higher on carcasses chilled over a weekend than on carcasses chilled for 24 h. The total number of bacteria on carcasses processed for domestic markets was similar to that on carcasses processed for export markets. E. coli O157 was not isolated from any of the 465 samples tested. Of the frozen export samples that tested positive, the mean of the log10 APC was 3.47/g, the geometric mean of the E. coli (biotype I) count was 9 MPN per g, and the geometric mean of the coliform count was 19 MPN per g. Of the frozen export samples tested, 48% were positive for E. coli (biotype I), 58% were positive for coliforms, and 6.5% were positive for Salmonella spp. E. coli O157 was recovered from 1 of 343 frozen sheep meat samples tested (0.29%). Bacterial counts were higher on samples of domestic product than on samples of export product. Results from both surveys are compared with data from similar studies conducted in other countries.

Microbiological quality of Australian beef carcass meat and frozen bulk packed beef.

Two studies were undertaken to determine the microbiological of beef carcass meat and frozen boneless bulk packed beef produced in Australia. Samples were collected from 1,063 beef carcasses and from 929 cartons of frozen boneless bulk packed beef over a period of approximately 12 months. Samples were collected from works processing beef carcasses for the Australian domestic market and from works targeting export markets. On carcasses processed for export markets, where bacterial counts were obtained, the log10 mean of the APC (aerobic plate count) was 3.13 CFU/cm2, the geometric mean of the coliform count was 19 MPN/cm2, and the geometric mean of Escherichia coli was 13 MPN/cm2. A small percentage (0.59%) of export samples were found positive for Listeria monocytogenes, 0.16% were positive of r coagulase-positive for Campylobacter jejuni/coli, 0.22% were positive for Salmonella spp., and 29% were positive for coagulase-positive Staphylococcus spp. Bacterial numbers were lower on carcasses processed for export markets and higher carcasses chilled for more than 24 h. Escherichia coli O157 was recovered from 4 of 893 export carcasses tested (0.45%). Of the export frozen boneless bulk packed beef samples that tested positive, the log10 mean of the APC was 2.5 CFU/g, the geometric mean of the coliform count was 15 MPN/g, and the geometric mean number of e. coli was 15 MPN/g. Three of 787 export frozen samples (0.38%) tested positive for Salmonella spp., E. coli O157 was not isolated from any of the 685 export frozen samples tested for this bacteria. Export samples tested for this bacteria. Export samples on average had lower APCs than domestic samples. Results from both surveys are compared with data from similar studies in other countries.

Biodegradation of Inion fast-absorbing biodegradable plates and screws.

Biodegradable plates and screws are recommended for use in surgery of the craniofacial skeleton of children. To be effective and not interfere with growth of the child's skull, the plates must biodegrade sufficiently to release the holding power of the plate and screw within 1 year. It is also essential that excessive foreign body reaction and cyst formation does not occur when the plates and screws biodegrade. The purpose of this experimental study was to evaluate the rate of biodegradation of Inion CPS Baby biodegradable plates and screws under different clinical circumstances in the rabbit craniofacial skeleton and evaluate their efficacy for use in pediatric craniofacial surgery. Foreign body reaction would be evaluated. Inion baby plates and screws were tested in a rabbit model. Plates were applied to the frontal bone, over a bony defect of the parietal bone, to a nasal bone fracture, and inserted in the subcutaneous space over the occipital bone in thirty 6-week-old rabbits. Six rabbits were euthanized at 9, 12, 15, and 18 months' postoperative time point and examined for residual plates and screws. Bone from each surgical site was excised, fixed by immersion in 10% neutral-buffered formalin, decalcified in Immunocal solution, and examined by 7-microm paraffin sections stained with hematoxylin and eosin. At 9 months, the plates and screws had effectively biodegraded and no longer had holding power on the bones. Fragmentation of the implant material was noted. Residual implant material was still present on gross and histologic examination in rabbits at 9, 12, 15, and 18 months. Residue of a screw was still palpable in 1 rabbit at 18 months. There was no evidence of cyst formation in any of the examined specimens. Macrophages and giant cells were present in most of the specimens at 9, 12, 15, and 18 months. Findings from the current study revealed a relative short resorption time (9 mo) and normal inflammatory sequelae in an adult rabbit model. These findings suggest that these plates may be used safely in fixing the pediatric craniofacial skeleton.

Effect of focal spot size on in-band 13.5 nm extreme ultraviolet emission from laser-produced Sn plasma.

The effect of focal spot size on in-band 13.5 nm extreme ultraviolet (EUV) emission from laser-produced Sn plasmas was investigated for an EUV lithography light source. Almost constant in-band conversion efficiency from laser to 13.5 nm EUV light was noted with focal spot sizes from 60 to 500 microm. This effect may be explained by the opacity of Sn plasmas. Optical interferometry showed that the EUV emission must pass through a longer plasma with higher density when the focal spot is large, and strong reabsorption of EUV light was confirmed by a dip located at 13.5 nm in the spectrum.

Extreme-ultraviolet spectral purity and magnetic ion debris mitigation by use of low-density tin targets.

We investigate the extreme-ultraviolet (EUV) emission from targets that contain tin as an impurity and the advantages of using these targets for ion debris mitigation by use of a magnetic field. The EUV spectral features were characterized by a transmission grating spectrograph. The in-band EUV emission energy was measured with a calorimeter of absolute calibration. The ion flux coming from the plume was measured with a Faraday cup. Our studies indicate that 0.5% Sn density is necessary to obtain a conversion efficiency very close to that of full-density Sn. The use of Sn-doped low-Z targets provides a narrower unresolved transition array and facilitates better control of energetic ions in the presence of a moderate magnetic field of 0.64 T.

Serotonin 5-HT(2) receptor activation induces a long-lasting amplification of spinal reflex actions in the rat.

1. C-fibre activation induces a long-term potentiation (LTP) in the spinal flexion reflex in mammals, presumably to provide enhanced reflexive protection of damaged tissue from further injury. Descending monoaminergic pathways are thought to depress sensory input but may also amplify spinal reflexes; the mechanisms of this modulation within the spinal cord remain to be elucidated. 2. We used electrical stimulation of primary afferents and recordings of motor output, in the rat lumbar spinal cord maintained in vitro, to demonstrate that serotonin is capable of inducing a long-lasting increase in reflex strength at all ages examined (postnatal days 2-12). 3. Pharmacological analyses indicated an essential requirement for activation of 5-HT(2C) receptors while 5-HT(1A/1B), 5-HT(7) and 5-HT(2A) receptor activation was not required. In addition, primary afferent-evoked synaptic potentials recorded in a subpopulation of laminae III-VI spinal neurons were similarly facilitated by 5-HT. Thus, serotonin receptor-evoked facilitatory actions are complex, and may involve alterations in neuronal properties at both motoneuronal and pre-motoneuronal levels. 4. This study provides the first demonstration of a descending transmitter producing a long-lasting amplification in reflex strength, accomplished by activating a specific serotonin receptor subtype. It is suggested that brain modulatory systems regulate reflex pathways to function within an appropriate range of sensori-motor gain, facilitating reflexes in behavioural situations requiring increased sensory responsiveness.

The head arterial glucose level is not the reference site for generation of the portal signal in conscious dogs.

Experiments were performed on twelve 42-h-fasted, conscious dogs to determine whether the head arterial glucose level is used as a reference standard for comparison with the portal glucose level in bringing about the stimulatory effect of portal glucose delivery on net hepatic glucose uptake (NHGU). Each experiment consisted of an 80-min equilibration, a 40-min control, and two 90-min test periods. After the control period, somatostatin was given along with insulin (7.2 pmol. kg(-1). min(-1); 3.5-fold increase) and glucagon (0.6 ng. kg(-1). min(-1); basal) intraportally. Glucose was infused intraportally (22.2 micromol. kg(-1). min(-1)) and peripherally as needed to double the hepatic glucose load. In one test period, glucose was infused into both vertebral and carotid arteries (HEAD(G); 22.2 +/- 0.8 micromol. kg(-1). min(-1)); in the other test period, saline was infused into the head arteries (HEAD(S)). One-half of the dogs received HEAD(G) first. When all dogs are considered, the blood arterial-portal glucose gradients (-0.52 +/- 0.07 vs. -0.49 +/- 0.03 mM) and the hepatic glucose loads (339 +/- 14 vs. 334 +/- 20 micromol. kg(-1). min(-1)) were similar in HEAD(G) and HEAD(S). NHGU was 24.1 +/- 3.8 and 25.1 +/- 4.6 micromol. kg(-1). min(-1), and nonhepatic glucose uptake was 46.1 +/- 4.2 and 48.8 +/- 7.0 micromol. kg(-1). min(-1) in HEAD(G) and HEAD(S), respectively. The head arterial glucose level is not the reference standard used for comparison with the portal glucose level in the generation of the portal signal.

The human tuftelin gene and the expression of tuftelin in mineralizing and nonmineralizing tissues.

Tuftelin has been suggested to play an important role during the development and mineralization of enamel, but its precise function is still unclear. This article reviews major milestones in the discovery, structural characterization, expression, localization, and conservation of tuftelin in different vertebrate species. It focuses on the structure of the human tuftelin gene, which has recently been deciphered [12]. It describes the exon-intron organization, sizes and structure, the promoter structure, and the newly discovered alternatively spliced human tooth-bud tuftelin mRNA transcripts. It also examines information on the structural motifs in the human-derived tuftelin protein and how they relate to tuftelin from other species. It reviews our recent results on the transcription of tuftelin mRNA and protein expression in several nonmineralizing soft tissues, using reverse-transcription polymerase chain reaction (RT-PCR) followed by DNA cloning and sequencing, indirect immunohistochemistry, immunohistochemistry combined with confocal microscopy, and in situ hybridization. These results and earlier Northern blot results show that tuftelin, in addition to being expressed in the developing and mineralizing tooth, is also expressed in several nonmineralizing soft tissues, suggesting that tuftelin has a universal function and/or a multifunctional role.