Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “root”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1998

The isolation of Actinomyces naeslundii from sound root surfaces and root carious lesions.

The isolation of Actinomyces naeslundii from sound, exposed root surfaces (n = 56) and soft and leathery root carious lesions (n = 71) was investigated. Root carious lesions were sampled after the removal of overlying plaque. Supragingival plaque or carious dentine was sampled using a sterile excavator, the samples were disaggregated and cultured on both selective and non-selective media. A. naeslundii isolates were identified to the genospecies using specific antisera. Significantly greater numbers and proportions of A. naeslundii genospecies 2 than A. naeslundii genospecies 1 were isolated from all sites sampled. There was no significant difference between the numbers and proportions of the two genospecies isolated from leathery and soft lesions. The relationship between the presence of A. naeslundii genospecies and aciduric and acidogenic organisms was investigated. Those sound exposed root surfaces from which A. naeslundii genospecies 1 and/or 2 were isolated yielded significantly lower numbers of lactobacilli and yeasts than the surfaces from which A. naeslundii were not isolated. This difference was also found in leathery lesions but not soft root carious lesions. The microflora of soft root carious lesions was found to comprise primarily gram-positive pleomorphic rods which formed 70+/-7.8% of the flora, while in plaque from exposed root surfaces and in infected dentine from leathery lesions the gram-positive pleomorphic rods represented only 35% of the flora.

Actinomyces↗
PubMed1978

The effectiveness of in vivo root planing in removing bacterial endotoxin from the roots of periodontally involved teeth.

In this study, scaling alone resulted in endotoxin values considerably greater than the values for healthy root surfaces. However, the root-planed Samples contained only about 1 ng more of endotoxin than did the healthy root surfaces. This small difference can be accounted for by the presence of small flecks of calculus left after root planing. Considering that out of a total sample size of 48 surfaces there was only 1 ng difference in the amount of endotoxin between planed teeth and uninvolved teeth, the basic conclusion must be that root planing, as performed in this study, was able to render diseased root surfaces approximately as free of detectable endotoxin as were uninvolved, healthy root surfaces of unerupted teeth.

Adult↗
PubMed2006

H wave and spinal root potentials in neuromonitoring of S1 root function during evacuation of herniated disc: preliminary results.

AIM: To determine the changes in the tibial H reflex and spinal nerve root potentials (SRPs) of the S1 root during posterior discectomy and the effects of surgical manipulation. METHODS: Tibial H reflex responses (M and H waves) were intermittently recorded from the soleus muscle by surface electrodes during different stages of surgery in 5 patients with S1 radiculopathy. All patients had Achilles reflex preserved bilateraly and no paresis on manual strength testing preoperatively. SRPs were additionally obtained by direct epidural recordings from the surgically exposed S1 root in 2 of them. RESULTS: The variations in the amplitude of H wave were minor and reversible upon the cessation of surgical manipulation of the root, but the H reflex was not lost either temporarily or permanently in any of the patients. Prolongation of H wave latency by up to 18% at the end of surgery in comparison with preoperative value was noticed in 4 patients. However, there was increased degree of desynchronization of the SRP in some phases of the spinal root manipulation, such as root mobilization before the disc incision and retraction during the disc evacuation. H waves and SRPs were continuously present during the surgery. Ankle jerks were preserved postoperatively in all 5 patients. CONCLUSION: Unremarkable variations in H wave latency may be followed by increased SRP desynchronization. Monitoring of the epidurally recorded SRPs seems to be more sensitive to surgical manipulations of the spinal nerve root than the tibial H reflex recordings from the soleus muscle.

Adult↗
PubMed1989

[The question of root resorption. Is the risk of root resorption related to the typology of the face?].

The mechanisms involved in root resorption are of the same nature than those leading to bone resorption. The state of calcification and the local conditions in the microenvironment are responsible for the different responses of alveolar bone and root with regard to calcified matrix resorption. Root resorption is commonly observed in association with impacted cuspids, acute chronical trauma, inflammatory or idiopathic conditions. Root resorption is more frequent in females and is independent on facial typology or orthodontic technique. Critical conditions to root integrity are often associated with heavy forces and periodontal ligament disruption. Root anatomy may also be a predisposing factor to resorption. Systematic radiological examination is the only way to control the onset of a root resorption process in orthodontic therapy.

Cephalometry↗
PubMed1996

Involvement of plasma membrane redox system in the generation of trans-root electrical potential difference in excised maize root.

Possible involvement of the plasma membrane bound redox system in the generation of the trans-root electrical potential difference (TRP) arising across 8 day old maize (Zea mays L. hybrid ZPSC704) roots was studied. Excised roots were exposed to artificial impermeable electron acceptors (potassium hexacyanoferrate III and potassium hexachloroiridate IV) in external solution, and TRP response, oxygen consumption rate, proton efflux and reduction of the electron acceptors were analyzed. The effect of hexacyanoferrate III (HCF III) was tested at three concentrations (0.1; 0.5 and 1.0 mmol/l), and hexachloroiridate IV (HCI IV) in the concentration range 10(-7)-5.10(-4) mol/l. Both electron acceptors depolarized the trans-root potential, an order of magnitude lower concentrations of hexachloroiridate producing a much more rapid depolarization of greater magnitude. The roots had a higher capacity to reduce 0.1 mmol/l hexachloroiridate than 1 mmol/l hexacyanoferrate. Also, an increased level of acidification induced by HCI IV than HCF III could be observed. The rate of oxygen consumption showed an increase of about 20% in both cases. These results prove that electron transplasma membrane transport process(es) contribute to the total trans-root electrical potential difference across an excised maize root.

Cell Membrane↗
PubMed2006

Surgical root restoration after external inflammatory root resorption: A case report.

External inflammatory root resorption after a jaw fracture is rare. This report describes a case of extensive external root resorption in the middle third of the root of a mandibular right canine after a mandibular fracture involving the tooth socket. Because of delayed treatment and damage to the root caused by a surgical screw, root canal treatment was performed followed by surgical intervention. The resorptive defect was debrided and part of the root was rebuilt with conventionally setting restorative glass ionomer cement. Postoperative follow-up revealed complete healing.

Adult↗
PubMed1990

Electronic determination of root canal length by newly developed measuring device. Influences of the diameter of apical foramen, the size of K-file and the root canal irrigants.

A new electronic root canal measuring device called "ENDEX" which is able to determine the root canal length under moistened conditions using a relative value of different alternative electric currents is discussed in this study. This study is designed to investigate the efficiencies of the new device, in vitro, with respect to change in the root canal environment; namely the influence of the size of K-file, the diameter of the apical foramen and the various root canal irrigants. According to the present study, it was confirmed that the location of the apical foramen was clearly detected under moistened root canal with saline solution using any size of K-file. The locations of the tip of K-files were 0.5 mm inside the apical foramen when the relative value displayed 0.3 Volt, so that the apical constriction could not disturb during root canal measurement. One of the big problem with prior electrical measurement devices was not being able to determine the canal length under moistened conditions. However with this improved device, intracanal irrigants, such as saline, 5% NaOC1, 14% EDTA and 3% H2O2 did not interfere in detecting apical foramen irregardless of the size of K-file and the size of the apical foramen.

Dental Pulp Cavity↗
PubMed1984

The ratio of dorsal root ganglion cells to dorsal root axons in sacral segments of the cat.

Processes of dorsal root ganglion cells are depicted as being unbranched until they reach the spinal cord or periphery. This is an important concept because, for example, branching of these processes might be a basis for referred pain. Recently several studies indicate that axons of rat dorsal root ganglion cells branch in or near the ganglion. The present study extends this work by showing that there are approximately 1.4 dorsal root axons for each dorsal root ganglion cell in sacral segments of the adult cat, and these data are interpreted as indicating that many dorsal root axons in this animal also branch. Thus this study provides further evidence to indicate that a revision of our ideas about the organization of primary sensory cells is desirable. In addition, this study provides data to indicate that the numbers of both dorsal root ganglion cells and dorsal root axons differ on the right as compared to the left side of the same segment.

Animals↗
PubMed2004

Replacement of the aortic root for acute prosthetic valve endocarditis: prosthetic composite versus aortic allograft root replacement.

OBJECTIVE: Aortic root replacement for prosthetic aortic valve endocarditis with accompanying destruction of the aortic root is a well-established surgical intervention. However, there is still no consensus whether prosthetic material or allogeneic material should be used. Here we report on our experience with prosthetic composite and aortic allograft root replacement in such patients during a 10-year interval. METHODS: From 1991 through 2001, 29 patients with prosthetic aortic valve endocarditis combined with aortic root destruction underwent reoperation at our institution. Sixteen patients received aortic root replacement with a cryopreserved aortic root allograft (group A) and 13 with a prosthetic composite graft (group B). The interval between the initial operation and reoperation was 29 months (range, 5-168 months) in group A and 55 months (range, 7-248 months) in group B. RESULTS: Hospital mortality was 18.5% (n = 5 patients, 3 in group A and 2 in group B). Median follow-up was 21 months (range, 1-48 months) for group A and 34 months (range, 1-152 months) for group B (P >.2). Survival at 1 and 5 years was 81% +/- 10% and 81% +/- 10% in group A and 85% +/- 10% and 85% +/- 10% in group B, respectively. No patient underwent reoperation for recurrent prosthetic aortic valve endocarditis. CONCLUSIONS: Our results indicate that excellent long-term results can be achieved regardless of the material used for aortic root replacement in patients with prosthetic aortic valve endocarditis.

Acute Disease↗
PubMed2006

Patient's age and extent of coronal and root destruction predict root canal treatment subsequent to after a full-cast crown.

DESIGN: A case-control study was carried out at the University of North Carolina School of Dentistry in the US. PARTICIPANT SELECTION: Dental charts from the university's dental clinical were audited for patients who had a single-cast crown between 1 January 1998 and 31 December 2002. Cases were defined as individuals who underwent root canal treatment at some time after the insertion of a single-cast crown up to 1 July 2004. The control group consisted of people who did not have root canal treatment after the insertion of a full-cast crown. DATA ANALYSIS: A list of 24 clinical factors was compared between groups (Table 1). Multiple logistic regression analysis was used to determine which preoperative nonprocedural factors were predictive of root canal treatment subsequent to a full-cast crown. RESULTS: A total of 6612 single-cast crowns (cast metal or porcelain fused to metal) were inserted during the 5-year period of interest. Of these, 5743 crowns, identified from 3357 patients' records (ie, the study subjects), were determined not to have undergone root-canal treatment prior to full-cast crown restorative treatment. Ninety-two subjects were initially determined to be eligible cases; ninety-two subjects were also therefore randomly selected from the remaining 3265 subjects to make up the control group. Twenty-six of the cases and 21 members of the control group were excluded because of incomplete records. The final case and control groups comprised 66 and 71 subjects respectively. Only subjects' age at the time of restorative treatment and their post-cementation tooth sensitivity was statistically significantly different between the two groups (P<0.05). Multiple logistic regression determined the statistically significant (P<0.05 ) predictors of case status: these were a patient's age and also the subgroup to which they were allocated according to the extent of pre-operative coronal and root destruction, on the basis of the restorative core size (more than three restored surfaces; Table 2). CONCLUSION: The age of a patient and the extent of coronal and root destruction can be used to predict the future need for root canal treatment on teeth for which a single-cast crown is planned.

Journal Article↗
PubMed1967

Effect of Root Temperature on Cytokinin Activity in Root Exudate of Vitis vinifera L.

Root exudates of plants of Vitis vinifera L. cv. Thompson Seedless, grown in nutrient cultures with root temperatures maintained at either 20 degrees or 30 degrees and with shoots at a common air temperature, were assayed for cytokinin activity. After chromatography of freeze-dried sap on paper with n-butanol/acetic acid/water (4:1:1). activity was detected with a soybean callus assay. For both root temperatures, major activity appeared between R(F) 0.6 and R(F) 0.8, at about the same concentration in each case. The major difference between the 2 samples was the presence of activity at R(F) 0.1 to 0.2 in the 20 degrees sample and its absence in the 30 degrees sample.The higher root temperature resulted in increased shoot and root elongation, increased dry matter accumulation by both shoots and roots, and also altered the morphological appearance of the roots.

Journal Article↗
PubMed1976

Effects of kinetin and root tip removal on exudation and potassium (rubidium) transport in roots of honey locust.

Exudation, (86)Rb transport, and water permeability were examined in excised roots of honey locust (Gleditsia triacanthos L.) treated by removing the tip 2 mm (tip-cut 2 mm) or tip 8 mm of the root, or by adding kinetin, or by both treatments. Tip removal increased the rate of exudation. Kinetin, 5 x 10(-6)m, inhibited exudation and Rb transport in tip-cut 2-mm roots; the inhibition was reversible. Kinetin inhibition of exudation was initially associated with lower K(Rb) transport and later with decreases in both ion transport and water permeability. Exudation was also inhibited at 10(-10) to 10(-7)m kinetin. Exudation from roots with intact tips was not altered by kinetin until after about 24 hours. Light during the exudation period had no significant (95%) influence on rate of exudation during the first 24 hours whether root tips were cut or kinetin applied.The results suggest the involvement of the root tip in regulating exudation in other parts of the root. This regulation might occur through cytokinin control of water permeability and the rate of ion transport.

Journal Article↗
PubMed1978

Regions of differential cell elongation and mitosis, and root meristem morphology in different tissues of geotropically stimulated maize root apices.

We examined cell length, mitosis, and root meristem "cuticle" in different tissues of geostimulated, red light-exposed primary roots of corn (Zea Mays, Wisconsin hybrid 64A x 22R). The examination was done at 15-minute intervals for a period of 240 minutes. Differences in cell elongation between the upper and lower sides were most prominent between 1.5 and 2.5 mm from the root meristem; the outer cortex had the greatest elongation growth, and the upper cells showed a significant increase in length compared to the lower. A differential mitosis was also found, with the lower tissue being greater. We infer that the mitotic activity is indicative of cell division, and this division occurs strictly in the first 1.5 mm of the root meristem. The combined effect of differential cell elongation and cell division results in the localization of the geotropic curvature in the 1.5- to 2.5-mm region from the root meristem. Mitosis that occurs primarily in the cortex and stele were asynchronous; the peak of cortical division preceded that of the stele. Both peaks occurred before the peak of geotropism. A densely stained layer separates the cap from the root meristem. This layer is thinner at the apex of the root meristem. The area of the thin region increased with time and peaked at 180 minutes after geostimulation, which was coincidental with the peak of the geotropic response.

Journal Article↗
PubMed1978

Metabolism of 2,4-dichlorophenoxyacetic Acid in soybean root callus and differentiated soybean root cultures as a function of concentration and tissue age.

The metabolism of [1-(14)C]2,4-dichlorophenoxyacetic acid (2,4-D) in soybean (Glycine max [L.] Merrill var. Amsoy) root callus and in differentiated soybean root cultures was investigated as a function of pesticide concentration and age of tissue. The chronological age of the tissue was found to be correlated with the mitotic index which reached a peak at 2 weeks and then declined. The metabolism of 2,4-D changed with age of the root callus tissue. The amount of free 2,4-D found in 3-week-old root callus tissue rapidly increased as the concentration of 2,4-D in the medium was increased from 10(-6) to 10(-5) molar, whereas the low level of aqueous (glycosides) and ether soluble metabolites (2,4-D amino acid conjugates) increased slowly. With 9-week-old root callus tissue, the amount of free 2,4-D remained at a relatively low, constant level (saturation level) as the concentration of 2,4-D in the medium increased. Under these conditions the aqueous metabolites increased only slightly but the ether fraction (2,4-D amino acid conjugates) rapidly increased. Thus, the older root callus tissue appeared to regulate the level of free 2,4-D at about 4 nanomoles per gram by converting any excess 2,4-D into amino acid conjugates.In 3-week-old, differentiated root cultures the metabolism of 2,4-D closely paralleled the metabolism found in the older 9-week-old callus tissue. The saturation level of free 2,4-D found in this tissue was only about 1 to 2 nanomoles per gram.

Journal Article↗
PubMed1981

Nitrate Reduction in Roots as Affected by the Presence of Potassium and by Flux of Nitrate through the Roots.

Dark-grown, detopped corn seedlings (cv. Pioneer 3369A) were exposed to treatment solutions containing Ca(NO(3))(2), NaNO(3), or KNO(3); KNO(3) plus 50 or 100 millimolar sorbitol; and KNO(3) at root temperatures of 30, 22, or 16 C. In all experiments, the accelerated phase of NO(3) (-) transport had previously been induced by prior exposure to NO(3) (-) for 10 hours. The experimental system allowed direct measurements of net NO(3) (-) uptake and translocation, and calculation of NO(3) (-) reduction in the root. The presence of K(+) resulted in small increases in NO(3) (-) uptake, but appreciably stimulated NO(3) (-) translocation out of the root. Enhanced translocation was associated with a marked decrease in the proportion of absorbed NO(3) (-) that was reduced in the root. When translocation was slowed by osmoticum or by low root temperatures, a greater proportion of absorbed NO(3) (-) was reduced in the presence of K(+). Results support the proposition that NO(3) (-) reduction in the root is reciprocally related to the rate of NO(3) (-) transport through the root symplasm.

Journal Article↗
PubMed1983

Potassium Transport in Corn Roots : II. The Significance of the Root Periphery.

The relative transport capabilities of the cells of the root periphery and cortex were investigated using a variety of experimental techniques. Brief (30 seconds to 1 minute) exposures with the penetrating sulfhydryl reagent, N-ethyl maleimide (NEM), and the impermeant reagent, p-chloromercuribenzene sulfonic acid (PCMBS), dramatically reduced (86)Rb(+) (0.2 millimolar RbCl) uptake into 2 centimeter corn (Zea mays [A632 x (C3640 x Oh43)]) root segments. Autoradiographic localization studies with [(3)H]NEM and [(203)Hg]PCMBS demonstrated that, during short term exposures with either reagent, sulfhydryl binding occurred almost exclusively in the cells of the root periphery.Corn root cortical protoplasts were isolated, and exhibited significant K(+)((86)Rb(+)) influx. The kinetics for K(+) uptake were studied; the influx isotherms were smooth, nonsaturating curves that approached linearity at higher K(+)(Rb(+)) concentrations (above 1 millimolar K(+)). These kinetics were identical in shape to the complex kinetics previously observed for K(+) uptake in corn roots (Kochian, Lucas 1982 Plant Physiol 70: 1723-1731), and could be resolved into a saturable and a first order kinetic component.The existence of a hypodermal apoplastic barrier was investigated. The apoplastic, cell wall binding dye, Calcofluor White M2R, appeared to be excluded from the cortex by the hypodermis. However, experiments with damaged roots indicated that this result may be an artifact resulting from the binding of dye to the epidermal cell walls. Furthermore, [(203)Hg] PCMBS autoradiography demonstrated that the hypodermis was not a barrier to apoplastic movement of PCMBS.These results suggest that although cortical cells possess the capacity to absorb ions, K(+) influx at low concentrations is limited to the root periphery. Cortical cell uptake appears to be repressed under these conditions. At higher concentrations, cortical cells may function to absorb K(+). Such a model may involve regulation of cortical cell ion transport capacity.

Journal Article↗
PubMed1991

Water Transport across Maize Roots : Simultaneous Measurement of Flows at the Cell and Root Level by Double Pressure Probe Technique.

A double pressure probe technique was used to measure simultaneously water flows and hydraulic parameters of individual cells and of excised roots of young seedlings of maize (Zea mays L.) in osmotic experiments. By following initial flows of water at the cell and root level and by estimating the profiles of driving forces (water potentials) across the root, the hydraulic conductivity of individual cell layers was evaluated. Since the hydraulic conductivity of the cell-to-cell path was determined separately, the hydraulic conductivity of the cell wall material could be evaluated as well (Lp(cw) = 0.3 to 6.10(-9) per meter per second per megapascal). Although, for radial water flow across the cortex and rhizodermis, the apoplasmic path was predominant, the contribution of the hydraulic conductance of the cell-to-cell path to the overall conductance increased significantly from the first layer of the cortex toward the inner layers from 2% to 23%. This change was mainly due to an increase of the hydraulic conductivity of the cell membranes which was Lp = 1.9.10(-7) per meter per second per megapascal in the first layer and Lp = 14 to 9.10(-7) per meter per second per megapascal in the inner layers of the cortex. The hydraulic conductivity of entire roots depended on whether hydrostatic or osmotic forces were used to induce water flows. Hydrostatic Lp(r) was 1.2 to 2.3.10(-7) per meter per second per megapascal and osmotic Lp(r) = 1.6 to 2.8.10(-8) per meter per second per megapascal. The apparent reflection coefficients of root cells (sigma(s)) of nonpermeating solutes (KCI, PEG 6000) decreased from values close to unity in the rhizodermis to about 0.7 to 0.8 in the cortex. In all cases, however, sigma(s) was significantly larger than the reflection coefficient of entire roots (sigma(sr)). For KCI and PEG 6000, sigma(sr) was 0.53 and 0.64, respectively. The results are discussed in terms of a composite membrane model of the root.

Journal Article↗