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PubMed2005

[Histological location of DMP1, OPN and BSP in cementum formation of mouse].

PURPOSE: To study the distribution of dentin matrix protein 1, osteopontin and bone sialoprotein during cementum formation and cementoblasts differentiation in mouse. METHODS: Thirty six BALB/c postnatal mice were divided into four groups according to the developing stages, nine in each was subdivided into three parts randomly to examine the location of DMP1, OPN and BSP, a tooth developing study model was built and examined using histological methods correspondingly. PV two steps immunohistochemical assay was used to localize the distribution of the three regulatory factors timely and spatially. Repeated measures ANOVA and statistical analysis software of CMIAS were used to analyze the intensity of the dyed images. RESULTS: There was a series expression of the three regulatory proteins. DMP1 was expressed in the dental follicle cells in day 5 of postnatal stages and negatively expressed when the cell began to differentiate; meanwhile, since day 10 and on OPN was positively located in cementoblasts until the root developed completely; but BSP was expressed in the same cell in day 15 to 20, and then decreased to be negative. There were significant differences statistically among the three factors in each stage observed in the study except OPN between day 15 and 25. CONCLUSIONS: There are different locations timely and spatially among the three proteins, it hints that they play important different roles during the differentiation of cementoblasts and formation of cementum.

Animals↗
PubMed2003

Root or crown: a developmental choice orchestrated by the differential regulation of the epithelial stem cell niche in the tooth of two rodent species.

The rodent incisor grows continuously throughout its lifetime. The epithelial stem cell niche is located at the apical end of the tooth and its progeny gives rise to the ameloblasts that form the hard enamel. Previously, mesenchymal FGF10 was shown to support the niche, in conjunction with epithelial Notch signaling. Here we show that in a different continuously growing tooth type, the molar of the sibling vole, a similar regulatory system is in place. Moreover, the identical expression pattern of Bmp4 compared to Fgf10 suggests that BMP4 could also be involved in the regulation of the epithelial stem cell niche. Notch and FGF10 signaling is mainly absent in the mouse molar, which stops growing and develops roots. The regulation of the epithelial stem cell niche seems to be flexible allowing for the existence of different tooth types, such as continuously growing teeth, and high and low crowned molars.

Animals↗
PubMed1984

Dental root agenesis secondary to irradiation therapy in a case of rhabdomyosarcoma of the middle ear.

There have been only a few published reports on the dental-facial effects of radiation therapy and the subsequent oral management of these patients. A case involving a 13-year-old black male patient with a history of rhabdomyosarcoma is presented. The patient received 4,050 rads of radiation to the right middle ear when he was 2 years of age. His residual medical and dental difficulties are apparently complications from the initial therapy. Examination of the oral cavity revealed bimaxillary micrognathia and marked loss of vertical dimension. A Class II facial profile with Class I molar relationship was observed. The mandible was thin and hypoplastic, with a small knife-edge alveolar ridge. The remaining eighteen erupted permanent teeth were very mobile, and root development had ceased after only initial formation. All of the teeth except the first permanent molars were extracted, and immediate partial dentures were inserted at the time of surgery. A discussion of therapeutic considerations follows the case report.

Abnormalities, Radiation-Induced↗
PubMed2004

Localisation of sulphated glycoconjugates during hyaline layer formation in rat molars by ultrastructural cytochemistry.

In order to study the presence of sulphated glycoconjugates in the first mineralised layer juxtaposed to the root dentine (the hyaline layer), we have examined the early stages of molar root development by ultrastructural cytochemistry using Cuprolinic Blue combined with enzymatic pretreatment. Upper molars from 10 to 13 day-old Wistar rats were fixed in 2.5% glutaraldehyde containing 0.05% Cuprolinic Blue in 25 mM sodium acetate, pH 5.6, containing 0.3 M MgCl2. Some specimens were previously treated with heparitinase or chondroitinase ABC. Our results showed sulphated glycoconjugate--Cuprolinic Blue complexes that appeared as electron opaque ribbon-like deposits in the unmineralised hyaline layer. Few complexes were detected adjacent to the dentinal surface. These complexes were removed by heparitinase, indicating that they contained heparan sulphate chains. In contrast, the complexes found in unmineralised cementum and root dentine were removed by chondroitinase, indicating that they contained chondroitin or dermatan sulphate chains. The complexes decreased after the initiation of mineralisation of hyaline layer and root dentine and they were no longer present in stages of fully mineralisation. We conclude that the hyaline layer only contains sulphated glycoconjugates prior to mineralisation, and that they may play a role in the regulation of the mineralisation.

Animals↗
PubMedDate not supplied

Radioprotective effect of novel disubstituted thioureas on pea (Pisum sativum L.) development.

The review presents our research on the influence of novel thiourea compounds on the biological and genetic effect of gamma-rays using in vivo and in vitro systems of pea. Some novel disubstituted thioureas: o-allylthioureidobenzoic acid (ATB); o-phenylthioureidobenzoic acid (PTB); N-allyl-N'-2-pyridylthiourea (A-2-PTU); N-phenyl-N'-2-pyridylthiourea (P-2-PTU) and 1,4-allylthioureidosalicylic acid (ATUS) were examined. Pea (Pisum sativum L.) seeds from five varieties were used. Experiments in vivo and in vitro were carried under laboratory, greenhouse and field conditions. The data revealed the PTB radioprotective effect demonstrated by: reduction of chromosome aberrations by 2 folds; 50% increase of germinating and surviving plants in M1; twice higher frequency of induced mutations in M2 generation relative to irradiation without PTB treatment; decreasing the level of induced radiation suppression leading to favorable effect on the initial stem and root development of pea. ATB radioprotective effect was demonstrated in vitro by: 25-35% stimulation of organogenesis; by 20-50% increase in bud formation; by 25% stimulation of growth. The effect of A-2-PTU and P-2-PTU depended on the irradiation dose. The protective effect of A-2-PTU is more pronounced at lower irradiation dose, while the effect of P-2-PTU is more pronounced at higher irradiation dose. ATUS, opposite to the other compounds, revealed radiosensibilizing effect by: 16-27% increase in lethality caused by gamma-rays leading to lower number of germinating and surviving plants in M1; 50% decrease in the number of induced mutations in M2 generation; limiting the types of induced mutations at the higher irradiation dose. As a result of the experiments useful mutation forms were obtained, characterized with: earliness, lodging and disease resistance; higher productivity.

Gamma Rays↗
PubMed2003

The use of Lepidium sativum in a plant bioassay system for the detection of microcystin-LR.

Toxin-producing cyanobacteria pose a worldwide health threat to humans and animals due to their increasing presence in both drinking and recreational waters. Detection of microcystins in water generally relies on specialised equipment and a delay of several days for transport and analysis. Little work has, however, been done on establishing a simple, cost-effective and sensitive plant bioassay for the detection of microcystin-LR (MCLR) in water at the WHO Tolerable Daily Intake guideline level of 1 microg/l. We investigated the effect of a MCLR extract at 1 and 10 microg/l on the growth of Lepidium sativum over 6 days. Exposure to 10 microg/l MCLR resulted in a significant decrease in root and leaf lengths and fresh weights of seedlings when compared to the controls. These results were consistent with seedlings exposed to pure MCLR at 10 microg/l. Seedlings exposed to 1 microg/l MCLR showed a significant decrease in root development from day 2 to day 6. Glutathione S-transferase and glutathione peroxidase activities were also significantly raised in plants from days 5 and 4, respectively, at both toxin levels investigated.

Animals↗
PubMed2003

Stimulation of hybrid poplar growth in petroleum-contaminated soils through oxygen addition and soil nutrient amendments.

Hybrid poplar trees (Populus deltoides x nigra DN34) were grown in a green-house using hydrocarbon-contaminated soil from a phytoremediation demonstration site in Health, Ohio. Two independent experiments investigated the effect of nutrient addition on poplar growth and the importance of oxygen addition to root development and plant growth. Biomass measurements, poplar height, and leaf color were used as indicators of plant health in the selection of a 10/5/5 NPK fertilizer applied at 1121 kg/ha (112 kg-N, 24.4 kg-P, 46.5 kg-K per ha) to enhance hybrid poplar growth at the Health site. Five passive methods of oxygen delivery were examined, including aeration tubes, gravel addition, and an Oxygen Release Compound (ORC). When ORC was placed in coffee filters above hydrocarbon-contaminated soil, a statistically significant increase of 145% was observed in poplar biomass growth, relative to unamended controls. The ORC in filters also stimulated significant increases in root density. A 15.2-cm interval of soil directly below ORC addition exhibited an increase from 2.6 +/- 1.0 mg/cm3 to 4.8 +/- 1.0 mg/cm3, showing stimulation of root growth in hydrocarbon-stained soil. The positive response of hybrid poplars to oxygen amendments suggests that overcoming oxygen limitation to plants should be considered in phytoremediation projects when soil contamination exerts a high biochemical oxygen demand, such as in former refinery sites.

Biodegradation, Environmental↗
PubMed2005

Field assessment of oxytetracycline exposure to the freshwater macrophytes Egeria densa Planch. and Ceratophyllum demersum L.

In a microcosm study, two aquatic macrophytes, Egeria densa and Ceratophyllum demersum were exposed to nominal concentrations of 0, 5, 20, 50, and 250 microg/L oxytetracycline (n=3), plus 20 microg/L oxytetracycline amended with additional nitrogen (N) and phosphorus (P). Responses were monitored bi-weekly over a six-week exposure period. Both plant species exhibited a significant decline in growth in the 250 microg/L oxytetracycline and the N- and P-amended units. Decreased light penetration resulting from accumulating oxytetracycline by-products appears to be the primary modifier in the growth of these plants. Increased susceptibility to oxytetracycline exposure was noted in some paired plantings (e.g., E. densa root development), relative to individual plants in these treatments, however, no clear explanation for this response is available. Based on the toxicity data generated in this study, we estimate that current concentrations of oxytetracycline in freshwater environments do not pose a direct risk to E. densa and C. demersum.

Anti-Bacterial Agents↗
PubMed1997

Tooth eruption through autogenous and xenogenous bone transplants: a histological and radiographic evaluation in beagle dogs.

The effect of implanting autogenous and xenogenous (Bio-Oss) bone transplants into metabolically active sites within beagle dog mandibles during permanent premolar tooth eruption was examined. Ten 14-week-old beagles were used. Before commencing the radiographic experiments, metal bone markers were placed in the caudal margin of the mandible at the age of 10 weeks. The deciduous first and third molar teeth were extracted and their sockets over the permanent second and fourth premolars were implanted with autogenous particulate enchondral iliac crest bone, autogenous particulate membraneous mandibular body bone, xenogenous bovine anorganic bone mineral spongiosa granules (1-2mm3) (Bio-Oss, Geistlich Pharma, Switzerland) of left empty. The third premolar served as control site. Standardized oblique lateral radiographs were taken once a week. A number of coordinates of defined points and structures were determined by means of a coordinate digitizing system. Animals were killed 4, 10 and 16 weeks after bone transplantation for histological examination of the transplantation sites. All premolars showed no delay in eruption or disruption of crown and root development. On histology, the Bio-Oss particles were not resorbed or integrated in the alveolar bone but were pushed forward into the gingiva. We have demonstrated that there is on difference in the eruption curve of the permanent premolars in the four groups (ANOVA P > 0.5) and that bone transplantation has no inhibitory effect on eruption (ANOVA P > 0.3) and crown development of the underlying permanent premolar but that Bio-Oss does not have the same resorbable or integrating capability as autogenous bone grafts.

Alveolar Process↗
PubMed1992

The isolation and primary culture of putative human root odontoblasts.

The use of procedures adapted from a routinely successful method of culturing bovine bone has led to the first system for the study of dentinogenesis in vitro. Two types of cells have been grown from pulp obtained from the growing root tips of impacted third molars extracted from 14- to 19-years olds: (1) epithelial-like cells that are probably derived from fragments of the epithelial root sheath and (2) odontoblast-like cells. The cultured epithelial-like cells grow out in distinctive rounded plaques while the odontoblast-like cells are tethered to and/or grow on top of the epithelial-like cells. The odontoblast-like cells produce mineralized matrix by 10 days when cultured on a defined mineralization formula containing conditioned medium obtained from fetal bovine bone cell cultures. Growth factors in this conditioned medium are important to cell proliferation and growth and to the synthesis of mineralized matrix. Sequential enzyme digestion in dispase and dispase/collagenase in serum-free Dulbecco's Modified Eagle's Medium is essential to obtaining adequate cell yields from the apical 3-5 mm of the developing root. Reduction of the number of fibroblasts by treating cultures with dispase in Tyrode's solution midway through the initial growth period enhances the purity of these cell cultures.

Adolescent↗
PubMed2000

The rib1 mutant is resistant to indole-3-butyric acid, an endogenous auxin in Arabidopsis.

The presence of indole-3-butyric acid (IBA) as an endogenous auxin in Arabidopsis has been recently demonstrated. However, the in vivo role of IBA remains to be elucidated. We present the characterization of a semi-dominant mutant that is affected in its response to IBA, but shows a wild-type response to indole-3-acetic acid (IAA), the predominant and most studied form of auxin. We have named this mutant rib1 for resistant to IBA. Root elongation assays show that rib1 is specifically resistant to IBA, to the synthetic auxin 2,4-dichlorophenoxyacetic acid, and to auxin transport inhibitors. rib1 does not display increased resistance to IAA, to the synthetic auxin naphthalene acetic acid, or to other classes of plant hormones. rib1 individuals also have other root specific phenotypes including a shortened primary root, an increased number of lateral roots, and a more variable response than wild type to a change in gravitational vector. Adult rib1 plants are morphologically indistinguishable from wild-type plants. These phenotypes suggest that rib1 alters IBA activity in the root, thereby affecting root development and response to environmental stimuli. We propose models in which RIB1 has a function in either IBA transport or response. Our experiments also suggest that IBA does not use the same mechanism to exit cells as does IAA and we propose a model for IBA transport.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2003

Ozone impacts on cotton: towards an integrated mechanism.

Vegetation removes tropospheric ozone (O(3)) mainly through uptake by stomata. O(3) reduces growth, photosynthesis, and carbohydrate allocation. Effects on mesophyll photosynthesis, may reducing carbohydrate source strength and, indirectly, carbohydrate translocation. Alternatively direct translocation, itself, could explain all of these observations. O(3)-reduced root proliferation inhibits exploitation of soil resources and interferes with underground carbon sequestration. Simulations with cotton suggest O(3)-disrupted root development could indirectly reduce shoot photosynthesis. Strong evidence for O(3) impacts on both carbon assimilation and carbon translocation exists, but data determining the primacy of direct or indirect O(3) effects on either or both processes remain inconclusive. Phloem loading may be particularly sensitive to O(3). Further research on metabolic feedback control of carbon assimilation and phloem loading activity as affected by O(3) exposure is required.

Air Pollutants↗
PubMed2006

Loss of At4 function impacts phosphate distribution between the roots and the shoots during phosphate starvation.

Plants display a range of adaptive responses to phosphate (Pi) starvation including an increase in the proportion of Pi allocated to the roots, which enhances lateral root development and consequently Pi acquisition. The mechanisms by which plants sense Pi and signal Pi reallocation are largely unknown. Previously, we cloned At4, a gene predicted to contain multiple short open-reading frames (ORFs), whose expression is strongly induced by Pi starvation. At4 is a member of a small gene family whose members, AtIPS1 and two additional genes reported here, At4.1 and At4.2, share little conservation among the predicted ORFs but high conservation of a 22-nt sequence located in the 3' half of the transcript. Here, we show that under Pi-starvation conditions, At4 is expressed in the vascular tissue and transcript levels are regulated by both cytokinin and ABA. at4, an At4 loss-of-function mutant fails to redistribute Pi to the roots correctly in response to Pi deprivation and At4 shoots continue to accumulate a greater proportion of Pi relative to wild type. Consistent with this, the primary root growth rate in at4 is faster than wild type in low-Pi conditions. The conserved sequence found in all members of the At4 gene family hybridizes to a small RNA present in Pi-starved roots. These data support a role for At4 in the internal allocation of Pi and suggest that the At4 gene is not only subject to Pi-starvation-inducible expression, but that transcript levels may be adjusted at a post-transcriptional level by the activity of an miRNA.

Abscisic Acid↗
PubMed1984

[Development of satellite-neuron relations in the spinal ganglia of the rat].

Cerebrospinal ganglia of 11-, 13-, 15-, 18- and 20-day-old embryos have been studied light- and electron-microscopically. On the 11th day of anlage the ganglia are presented exclusively as neuroblasts: the satellite-cells are formed later from lemmoblasts that install into the ganglion on the 13th-15th days both from the surrounding mesenchyme and from the developing roots and trunklets of the cerebrospinal nerves. In the ganglion they undergo proliferation and further differentiation. On the 15th day simple satellite-neuron interrelationships are formed: one satellite-cell is tightly connected with perikaryons of some neuroblasts and young neurons. On the 18th day around some neurons a double layered capsule is formed from the satellite-cells. Multilayered tunics are formed only on the 10th-15th day after birth. During the process of the capsule formation an unusual reactive character of the satellite-neuron interrelationships is revealed, it is manifested as, performed by the satellite-cells, an active microphagocytosis of the perikaryon cytoplasmic processes and the initial segment of the sensitive neuron main process. In embryogenesis the lemmocyte-axon interrelationships develop earlier than the satellite-neuronal ones.

Animals↗
PubMed1984

Four-year longitudinal study of the periodontal health status of overdenture patients.

Seven patients with a total of 12 roots were treated with overdentures (maxillary, mandibular, or both) and recalled at 6-month intervals for a period of 4 years. A periodontist evaluated the periodontal health status of the abutment roots after complete periodontal therapy, immediately prior to placement of the overdentures, and at all recall visits. The gingival tissues around all the abutments were slightly erythematous and edematous and bled on probing. There were no statistically significant changes in pocket depth or in apparent width of attached gingiva on an intra-arch basis. However, statistically significant changes were found on comparison between the maxillary and mandibular arches. Over the 4-year period 50% of the roots remained immobile, 25% of the roots that were initially mobile exhibited no mobility, and 25% of the roots decreased in mobility. Five of 14 roots in eight patients (35.7% of the abutment roots) developed dental caries. Periodic recalls to reinforce plaque control measures, to provide adjunctive periodontal therapy, and to correct and adjust the prostheses of patients treated with overdentures are important factors in the longterm success of this treatment modality. Biomechanically, treatment of patients with overdentures is a valid practical alternative to complete dentures.

Dental Abutments↗
PubMed2003

Effects of excess copper on growth of wild rice (Zizania palustris) seedlings tested in reconstituted and natural waters.

Dissolved copper was toxic to wild rice (Zizania palustris) seedlings when exposed in water from the seed collection site of Swamp Creek, Crandon, Wisconsin, USA, and in laboratory-prepared artificial or reconstituted water. Seeds for the study were harvested, then held through a portion of dormancy, in Swamp Creek. After 60 days they were shipped to a laboratory, chilled, and tested with copper after germination. The end point of the tests was net gain in wet weight of the seedlings; additionally, a pronounced reduction in root development was observed. Using measured concentrations, the lowest no-observable-effect concentration (NOEC) in our study was 37 microg/liter in Swamp Creek water and the lowest-observable-effect concentration (LOEC) was 59 microg/liter. However, it appeared that there was a point at which concentrations of copper above 400 microg/liter did not result in any measurable effect or exhibit a definitive dose-response. Because the results in Swamp Creek water were more relevant to the possibility of local metals additions and the association of reduced seedling growth by copper was more powerful in this water, we derived an equation to express the relationship between copper concentration and toxicity for Swamp Creek water. As an example, we would expect a 3.0% reduction in seedling growth at 5.0 microg/liter copper. Seedling roots were particularly affected and the resultant plants may be less well anchored and more susceptible to dislodging than plants not exposed to copper. Further refinement of the methodology may be used to address effects of other contaminants impacting rice beds in North America.

Copper↗
PubMed2003

Comparison of 233U and 33P uptake and translocation by the arbuscular mycorrhizal fungus Glomus intraradices in root organ culture conditions.

This study aimed to quantify and compare 233U and 33P uptake and translocation by hyphae of the arbuscular mycorrhizal (AM) fungus Glomus intraradices in root organ culture conditions with transformed carrot (Daucus carota L.) roots as host. Mycorrhizal roots were grown in two-compartment Petri dishes to spatially separate a root compartment (RC) and a hyphal compartment (HC). The HC was labelled with 8.33 Bq 233U ml(-1) and 13.33 Bq 33P ml(-1). After 2 weeks contact between hyphae and the labelled solution, 233U and 33P activities were measured in the RC and in the HC. 233U and 33P were taken up by the extraradical AM mycelium grown in the HC and this uptake represented 4.4% and 16% of the initial isotope supply, respectively. The translocation into roots developing in the RC via hyphae accounted for 5.9% and 72% of the initial isotope supply, respectively. Thus, both uptake and translocation were much higher for 33P than for 233U. This suggests (1) the existence in hyphal tissues of efficient mechanisms limiting the uptake and translocation of non-essential elements such as U, and (2) that the hyphae have a higher sequestration than translocation function for U, and the converse for P.

Daucus carota↗
PubMed2000

Direct evidence for ribonucleolytic activity of a PR-10-like protein from white lupin roots.

An abundant 17 kDa protein which was isolated and characterized from 10-day old healthy root tissue of white lupin (Lupinus albus) proved to have a high sequence similarity to pathogenesis-related proteins found in other species. Subsequently, a corresponding clone (LaPR-10) was identified in a cDNA library prepared from the same tissue that exhibited a high amino acid sequence similarity to a number of the PR-10 family proteins. The clone contains an open reading frame encoding a polypeptide of 158 amino acids, with a predicted molecular mass of 16,905 Da and an isoelectric point of 4.66. Southern blot analysis indicates that LaPR-10 is likely a single-copy gene, or a member of a small gene family. The clone was expressed in Escherichia coli, and its protein product was purified to near homogeneity. Both the native and the recombinant proteins were immunorecognized by antibodies raised against pea PR-10 proteins, and exhibited a ribonucleolytic activity against several RNA preparations, including lupin root total RNA. Characterization of its enzymatic properties indicates that the LaPR-10 protein belongs to the class II ribonucleases. We present evidence that the white lupin 17 kDa protein is constitutively expressed during all stages of root development and, to a lesser extent, in other plant parts. In addition, we demonstrate the presence, in the LaPR-10 amino acid sequence, of a number of motifs that are common to most PR-10 proteins, as well as a RGD motif that is shared only with the alfalfa SRG1 sequence.

Amino Acid Sequence↗