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At least 487 records · Page 27Linked to original sources
PubMed2005

[The influence of partial dorsal root rhizotomy on IGF-I expression in spared root ganglion and spinal cord].

OBJECTIVE: To explore the temporospatial changes of IGF-I expression in the spared dorsal root ganglia (DRG, L6) on the operated side and un-operated side, in the spinal lamina II (L3, L5, L6) and Clarke's nucleus (L3) of the adult cats that have undergone partial dorsal rhizotomy, and compare them against those of the normal adult cats so as to unveil the relation between IGF-I and the plasticity of spinal cord. METHODS: Fifteen male adult cats were divided into three groups. The cats of two groups were subjected to unilateral partial dorsal root rhizotomy (L1-L5, L7-S2 DRG were sectioned, but L6 was spared) and were sacrificed at 7 days and 14 days after operation. The bilateral L6 dorsal root ganglia and L3, L5, L6 spinal cord of all groups were made into frozen sections 20 microm thick. Then, the sections were stained by the immunohistochemistry ABC method using IGF-I (1:200, Santa Cruz) antibody. The distribution and the number of IGF-I positive neurons in bilateral spared DRG (L6) on the operated/un-operated side, in spinal lamina I (L3, L5, L6) and in Clarke' nucleus (L3) of each animal were observed and counted. All data were analyzed by one-way ANOVA, SNK-q test and paired-t test. RESULTS: (1) Seven days after partial dorsal root rhizotomy, the number of IGF-I positive neurons in spared DRG on the operated side declined as compared with that of normal group (P<0.05), but it was not significantly different from that of L6 spared DRG on the un-operated side (P>0.05). On the 14th day, the IGF-I expression in neurons of L6 DRG on the operated side was significantly lower than that of normal group and that of L6 spared DRG on the unoperated side (P<0.01), but it was not significantly different from that of the 7th day group (P>0.05). (2) There was no difference in number of IGF-I positive neuron in L3, L5, L6 spinal lamina II between normal group, 7th day post-operation group and 14th day post-operation group (P>0.05). After operation, IGF-I expression in Clarke's nucleus declined on the 7th day (P<0.05) and came back to normal level on the 14th day (P>0.05). CONCLUSION: Partial dorsal root rhizotomy can lead to the change of IGF-I expression in bilateral DRG and Clarke's nucleus, which suggests that IGF-I be related with spinal cord plasticity.

Animals↗
PubMed2005

[Expression of Bax, Bcl-2 and caspase-3 in spared dorsal root ganglion after partial dorsal root rhizotomy].

OBJECTIVE: Investigating the expression of Bax, Bcl-2 and Caspase-3 in dorsal root ganglion after partial dorsal root rhizotomy in spared root. METHODS: Adult cats were used. The study comprised a normal control group (n=5) and three expriment groups (n=5 per group). The unilateral root rhizotomy was performed on the 15 cats of the 3 experiment groups. On the 3rd, 7th and 14th days after partial dorsal rhizotomy, the DRG (L6) of 5 cats per batch were taken and made into frozen sections and were stained under the same condition using specific Bax, Bcl-2 and Caspase-3 antibody by ABC method. The Bax, Bcl-2 and Caspase-3 positive large-, medium- and small-sized neurons in DRG were counted in the 3 experiment groups and in the normal control group. RESULTS: In the intact animals of the normal control group, the Bax, Bcl-2 and Caspase-3 immunoreactants were mainly distributed in medium, small neurons and a few large neurons. The number of Bax positive neurons in spared DRG of the 3rd day group increased apparently as compared with that of the normal control group but decreased apparently in the 14th day group and showed no significant difference when compared versus control (P>0.05). There was no significant difference between the 14th day group and normal control group. Bcl-2 expression in spared DRG displayed no difference among the four groups. The number of Caspase-3 positive neurons in spared DRG of the 3rd day group increased apparently when compared against control (P<0.05), but it was not significantly different from that of the 7th day and 14th day groups (P>0.05). CONCLUSION: Partial dorsal root rhizotomy mainly has an effect on the expressions of Bax, Bcl-2 and Caspase-3 in medium- and small-sized neurons of spared DRG, the peaks of the expressions may appear 3-7 d after the operation.

Animals↗
PubMed1981

A comparison of experimental procedures of investigation of the dorsal root evoked ventral root reflex in the frog.

Effects of the drug methyl-m-aminobenzoate (MS-222 Sandoz) on the dorsal root evoked ventral root responses were studied by electrophysiological methods in the frog spinal cord. A fairly quick and marked depression of the response was observed from which complete recovery was seen within 60 minutes. Larger doses or repeated injection of small amounts of the drug prolonged the recovery and the monosynaptic discharge component of the ventral root reflex often deteriorated irreversibly. - In further experiments, monosynaptic ventral root discharges were demonstrated in spinal cords isolated from the vertebral canal and kept in Ringer solution. The results are discussed in the light of controversial views about the occurrence of monosynaptic ventral root discharge to stimulation of the primary afferents in the amphibian spinal cord.

Aminobenzoates↗
PubMed1997

In vitro evaluation of effects of ultrasonic root-end preparation on resected root surfaces.

This in vitro study investigated structural alterations in resected roots that had root-end preparations made with a conventional microhead handpiece and ultrasonics at two intensity levels. Root ends were examined with fluorescence confocal microscopy. Serial histologic sections to the 2 mm levels and then at the level of 3 mm and 4 mm from the resected surface were examined. Statistical analysis of the confocal data indicated no significant difference between the groups in the number and length of the fractures. Results of the histologic data indicated that root ends prepared by ultrasonics had a statistically greater number of fractures than both the control and the conventionally prepared groups. The latter did not differ significantly from each other.

Apicoectomy↗
PubMed2002

Long-term calcium hydroxide as a root canal dressing may increase risk of root fracture.

It has been proposed (Cvek 1992) that immature teeth are weakened by filling of the root canals with calcium hydroxide dressing and gutta-percha. The aim of the present study was to test the hypothesis that dentin in contact with calcium hydroxide would show a reduction in fracture strength after a certain period of time. Immature mandibular incisors from sheep were extracted and divided into two experimental groups. Group 1: the pulps were extirpated via the apical foramen. The root canals were then filled with calcium hydroxide (Calasept) and sealed with IRM(R) cement, and the teeth were then stored in saline at room temperature for 0.5, 1, 2, 3, 6, 9, or 12 months. Group 2: the pulps were extirpated and the root canals were filled with saline and sealed with IRM(R) cement. The teeth were then stored in saline for 2 months. Intact teeth served as controls and were tested immediately after extraction. All teeth were tested for fracture strength in an Instron testing machine at the indicated observation periods. The results showed a markedly decrease in fracture strength with increasing storage time for group 1 (calcium hydroxide dressing). The results indicate that the fracture strength of calcium hydroxide-filled immature teeth will be halved in about a year due to the root filling. The finding may explain the frequent reported fractures of immature teeth filled with calcium hydroxide for extended periods.

Analysis of Variance↗
PubMed1995

Mandibular canine with two roots and three root canals.

A rare case of root canal retreatment in a lower canine with two roots and three canals is presented. While the presence of two roots and two canals in one root is not uncommon, the finding of three canals in a lower canine appears not to have been reported previously.

Adult↗
PubMed1997

Treatment of a horizontal root fracture by vital root submergence.

Cervical third horizontal root fractures in immature permanent teeth often present complicated and unpredictable treatment options. This case report describes the successful management of a horizontal root fracture in an open apex tooth by vital root submergence and subsequent nonsurgical root canal therapy.

Child↗
PubMed1995

Effect of ND:YAG laser irradiation and root planing on the root surface: structural and thermal effects.

Effects of ND:YAG laser irradiation on untreated and root planed tooth roots were investigated to determine whether a cleaning effect and/or removal of smear layer could be achieved without concomitant microstructural or thermal damage. Sixty (60) healthy extracted teeth were either untreated, irradiated only, root planed only, or irradiated and root planed. Intra-pulpal and surface temperatures were monitored during irradiation, then SEM was performed. Smear layer elimination was achieved without inducing hard tissue microstructural damage at 5W, using pulse durations and intervals of 0.1 s, a fluence of 0.77 J/cm2, and a total energy density of approximately 700 J/cm2. However, these results were not consistent in all samples. At these parameters, intra-pulpal temperature increases of 9 to 22 degrees C and surface temperature increases of 18 to 36 degrees C were recorded. Thus, despite their effectiveness for smear layer removal, these parameters may not be appropriate for clinical use as an adjunct to conventional periodontal therapy.

Body Temperature↗
PubMed1999

Periodontal esthetics and soft-tissue root coverage for treatment of cervical root caries.

As the pace of change accelerates in periodontics and esthetic dentistry, an increasing number of procedures are being developed that require knowledge and treatment from both fields. The synergy developed by combining these two fields of dentistry allows for better esthetic outcomes for our patients. Two of these procedures include esthetic crown lengthening and soft-tissue root coverage. As demonstrated in this article, soft-tissue root coverage can be performed on previously restored roots and as an option for treating root caries.

Anti-Bacterial Agents↗
PubMedDate not supplied

Comparative SEM study on the effect of root conditioning with EDTA or tetracycline Hcl on periodontally involved root surfaces.

This study compared the surface characteristics of periodontally diseased single human teeth extracted after treatment with either EDTA or Tetracycline Hcl. The study was comprised of 30 teeth from 20 patients with advanced periodontal disease. Diseased root surfaces were root planed by hand curette or finishing bur. The teeth were sectioned and solutions of EDTA (pH 7.3) or Tetracycline Hcl (pH 1.8) were applied to the surface with cotton pellets for 3 minutes using light pressure. Specimens were processed and examined by Scanning Electron Microscope. The surfaces of both etched treated sets of specimens differed considerably from specimens treated with root planing alone, regardless of the root planing method. The etched specimens exhibited numerous dentinal tubules exposed by the removal of smear layer.

Acid Etching, Dental↗
PubMed1991

Root growth regulation and gravitropism in maize roots does not require the epidermis.

We have earlier published observations showing that endogenous alterations in growth rate during gravitropism in maize roots (Zea mays L.) are unaffected by the orientation of cuts which remove epidermal and cortical tissue in the growing zone (Björkman and Cleland, 1988, Planta 176, 513-518). We concluded that the epidermis and cortex are not essential for transporting a growth-regulating signal in gravitropism or straight growth, nor for regulating the rate of tissue expansion. This conclusion has been challenged by Yang et al. (1990, Planta 180, 530-536), who contend that a shallow girdle around the entire perimeter of the root blocks gravitropic curvature and that this inhibition is the result of a requirement for epidermal cells to transport the growth-regulating signal. In this paper we demonstrate that the entire epidermis can be removed without blocking gravitropic curvature and show that the position of narrow girdles does not affect the location of curvature. We therefore conclude that the epidermis is not required for transport of a growth-regulating substance from the root cap to the growing zone, nor does it regulate the growth rate of the elongating zone of roots.

Biological Transport↗
PubMed1999

Cervical root stimulation at C5/6 excites C8/T1 roots and minimizes pneumothorax risk.

Needle electrical cervical root stimulation may be performed lateral to the C5/C6 or C7/T1 spinous process interspaces. Pneumothorax has been reported following C7/T1 root stimulation. We evaluated the efficacy of a modified C5/C6 stimulation technique in exciting C8/T1 roots in 15 normal subjects and 36 patients with motor neuron disease (204 procedures). No instances of a 50% or greater amplitude decline occurred. C5/C6 interspace stimulation, therefore, may be used to excite C8/T1 roots while minimizing pneumothorax risk.

Electric Stimulation↗
PubMed2005

Disturbed root development of permanent teeth after pediatric stem cell transplantation. Dental root development after SCT.

BACKGROUND: Deficient dental root development has been reported after conventional pediatric anticancer therapy, but less information is available on stem cell transplantation (SCT) recipients. METHODS: Root-crown (R/C) ratios of fully developed permanent teeth were assessed from panoramic radiographs of 52 SCT recipients, who were treated when they were age < 10 years. Using standard deviation scores (SDSs), the authors compared the R/C ratios to the corresponding tooth and gender-specific values in a healthy population. The percentage of affected R/C ratios per individual was examined in a subgroup of 39 (SG39) patients with advanced tooth development. The effects of total body irradiation (TBI) and SCT age on the R/C ratios were studied in TBI and high-dose chemotherapy (HDC = non-TBI) groups and in 3 age groups (< or = 3.0 years, 3.1-5.0 years, > or = 5.1 years). RESULTS: Per individual, 77% of the fully developed permanent teeth were affected in SG39. At the tooth level, in 77% of the 945 teeth studied (52 patients), the R/C ratios were outside +/-2 SDSs. More teeth were affected in the TBI (85%) than in the non-TBI (55%) group (P < 0.001). The teeth of the patients who were ages 3.1-5.0 years old at SCT presented with the most severe aberrations of the R/C ratio (mean SDS = -4.4) whereas the teeth of the youngest (age < or = 3.0 years) and the oldest (age > or = 5.1 years) patients were equally affected (mean SDSs = -3.1 and -3.0, respectively). CONCLUSIONS: Disturbances of dental root growth always followed pediatric SCT. HDC alone intensely harmed root growth but TBI further increased the adverse effects that were most extensive in the patients 3.1-5.0 years at SCT. These sequelae should be taken into account during the lifelong dental follow-up to minimize the clinical consequences of dental injuries.

Adolescent↗
PubMed2003

Role of Hertwig's epithelial root sheath cells in tooth root development.

During tooth development, after the completion of crown formation, the apical mesenchyme forms the developing periodontium while the inner and outer enamel epithelia fuse below the level of the crown cervical margin to produce a bilayered epithelial sheath termed Hertwig's epithelial root sheath (HERS). The role of HERS cells in root formation is widely accepted; however, the precise function of these cells remains controversial. Functions suggested have ranged from structural (subdivide the dental ectomesenchymal tissues into dental papilla and dental follicle), regulators of timing of root development, inducers of mesenchymal cell differentiation into odontoblasts and cementoblasts, to cementoblast cell precursors. The characterization of the HERS phenotype has been hindered by the small amount of tissue present at a given time during root formation. In this study, we report the establishment of an immortal HERS-derived cell line that can be maintained in culture and then induced to differentiate in vitro. Characterization of the HERS phenotype using reverse transcriptase-polymerase chain reaction and Western blot immunostaining suggests that HERS cells initially synthesize and secrete some enamel-related proteins such as ameloblastin, and then these cells appear to change their morphology and produce a mineralized extracellular matrix resembling acellular cementum. These studies suggest that the acellular and cellular cementum are synthesized by two different types of cells, the first one by HERS-derived cementoblasts and the later by neural crest-derived cementoblasts.

Alkaline Phosphatase↗
PubMedDate not supplied

Efficient method for determining the glycyrrhizin content of fresh and dried roots, and root extracts, of Glycyrrhiza species.

A reliable and efficient method suitable for the selective analysis of the glycyrrhizin content of fresh and dried roots of Glycyrrhiza species and of root extracts is described. The method was optimised for recovery and analysis of glycyrrhizin after conversion to its aglycone, 18 beta-glycyrrhetinic acid. The reversed-phase HPLC system was developed using a sterically protected C8 column that allowed UV detection of the aglycone at 254 mm without interference from co-occurring components. The average recovery through the method was determined at 83%, with a range of 65-99%. Analysis of 150 dried root samples gave levels of glycyrrhizin consistent with earlier reported values. A comparison of post-harvest treatment conditions. showed that the drying of root samples at up to 65 degrees C did not result in any measurable reduction in glycyrrhizin.

Chromatography, High Pressure Liquid↗
PubMed1993

Putative inhibitory extracellular matrix molecules at the dorsal root entry zone of the spinal cord during development and after root and sciatic nerve lesions.

The dorsal root entry zone (DREZ) of the spinal cord is the interface between the central and peripheral nervous systems and is the pathway through which sensory afferents enter the central nervous system during development. However, in the rat, the DREZ becomes a boundary to regenerating sensory axons after Postnatal Days 2-3. The cellular and molecular mechanisms that cause regenerative failure at the DREZ after the critical period for regeneration are unknown. Recent studies demonstrate that two extracellular matrix molecules, Cytotactin/tenascin (CT) and chondroitin 6-sulfate-containing proteoglycans (C-6S-PG) are present in normal boundary regions of the brain and spinal cord during development. In the present study we sought to visualize the expression of these two putative inhibitory molecules in the DREZ of normally developing and adult animals, and also in animals after injury. CT and C-6S-PG spread laterally from the midline to the DREZ by Postnatal Day 3, correlating exactly with the end of the critical period. The staining intensity for these two molecules increases further in the DREZ after root lesions, but not sciatic lesions, at ages when axons cannot regenerate into the spinal cord. Following root lesion CT and C-6S-PG were mostly present in association with reactive glia at the DREZ and in white matter, rather than with reactive glia in grey matter of the dorsal horn, suggesting that astroglia are heterogeneous in their response to root lesion. The coexpression of CT and C-6S-PG may create a molecular barrier which might channel or deflect axons at the DREZ during CNS development and inhibit their growth during regeneration.

Aging↗
PubMed1977

Electron microscopic identification of postsynaptic dorsal root terminals: a possible substrate of dorsal root potentials in the frog spinal cord.

Dorsal root fibers were labeled with cobaltous chloride iontophoresis for electron microscopic investigations. In the base of the dorsal horn, where most of the coarser collaterals of dorsal root fibers terminate, many dorsal root terminals were found in postsynaptic relation to synapsing profiles. According to their morphological characteristics, three kinds of presynaptic terminals could be discerned in these complex synapses: axon terminals with spheric vesicles, axon terminals with flattered vesicles and presynaptic dendrites. These latter terminals contained relatively few flattened vesicles accumulated adjacent to a short synaptic articulation surface, and they were rich in cytoplasmic organelles. The functional significance of these structural specializations in the mediation of dorsal root potentials and recurrent inhibition is discussed.

Animals↗