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Phylogeny and taxonomy of root-inhabiting Cryptosporiopsis species, and C. rhizophila sp. nov., a fungus inhabiting roots of several Ericaceae.

Three Cryptosporiopsis species have thus far been isolated from roots of woody plants. A fourth species, which was recently isolated from roots of Calluna vulgaris, Erica tetralix, Vaccinium vitis-idaea, and V. myrtillus in The Netherlands, is described here as new. Sporulation on the natural substratum has not been observed and the morphological description of this fungus is therefore based on characters expressed on oatmeal and malt extract agars. The phenotypic characters indicated a close relationship with the other root-inhabiting species of Cryptosporiopsis and species of the associated teleomorph genus Pezicula. This relationship was confirmed by phylogenetic analyses using sequence data of the 5.8S nuclear rDNA and flanking internal transcribed spacers. In order to facilitate recognition of this possibly under-recognized category of root inhabitants, a key to the root-inhabiting Cryptosporiopsis species based on characters in vitro is given.

Ascomycota↗

Review on tropical root and tuber crops. II. Physiological disorders in freshly stored roots and tubers.

Tropical root and tubers, including cassava, sweet potato, yams and aroids, have been reported to show an increase in respiratory activity after harvest and injury and subsequent storage in association with their deterioration. This leads to loss of water and carbohydrate. Cassava roots often show discoloration of the tissue with development of pigments in the xylem vessels (vascular streaking or primary/physiological deterioration). This has been established to be enzymatic in nature. Pruning the cassava stem, leaving about a 20- to 30-cm stub prior to harvest, could delay the onset of primary deterioration. Sweet potato roots and yam tubers show a peak respiratory activity immediately or 1 d after harvest. The respiratory rate, however, declines during the subsequent storage period. Yam tubers show a further increase in respiratory activity at the breakage of dormancy occurring at the time of sprouting. Dormancy in yam tubers has been studied in some detail. Different species of yams vary in their dormancy period, a major factor that accounts for the variation in their storage life. Little information is available on the dormancy of sweet potato and aroids. Tropical roots and tubers exhibit "chilling injury" when stored at temperatures below a critical level. The critical cold-storage temperatures range between 10 and 15 degrees C for different tropical root and tuber crops.

Carbohydrates↗

Staining human lymphocytes and onion root cell nuclei with madder root.

We performed staining experiments on cells using natural dyes and different mordants using techniques that are used for wool and silk dyeing. The natural dye sources were madder root, daisy, corn cockle and yellow weed. Ferrous sulfate, copper sulfate, potassium tartrate, urea, potassium aluminum sulfate and potassium dichromate were used as mordants. Distilled water, distilled water plus ethanol, heptane, and distilled water plus methanol were used as solvents. All dye-mordant-solvent combinations were studied at pH 2.4, 3.2 and 4.2. The generic staining procedure was to boil 5-10 onion roots or stimulated human lymphocyte (SHL) preparations in a dye bath on a hot plate. Cells were examined at every half hour. For multicolor staining, madder-dyed lymphocytes were decolorized, then stained with Giemsa. The AgNOR technique was performed following the decolorization of Giemsa stained lymphocytes. Good results were obtained for both onion root cells and lymphocytes that were boiled for 3 h in a dye bath that included 4 g madder root, 4 g ferrous sulfate as mordant in 50 ml of 1:1 (v/v) methanol:distilled water. The pH was adjusted to 4.2 with 6 ml acetic acid. We conclude that madder root has potential as an alternative dye for staining biological materials.

Azure Stains↗

Chilling root temperature causes rapid ultrastructural changes in cortical cells of cucumber (Cucumis sativus L.) root tips.

Examination of root tips from cucumber (Cucumis sativus L.) seedlings grown at 8 degrees C for varying periods ranging from 15 min to 96 h, showed marked changes in the ultrastructure of cortical cells within only 15 min of exposure. Greater parts of the cortex were affected with longer periods of exposure, but the sequence of morphological changes in cell components was similar to that found for the roots exposed for 15 min. The effect of chilling injury included alterations in cell walls, nuclei, ER, mitochondria, plastids, and ribosomes. The extent of alterations varied greatly among cells, moderate to severe alterations to cell components being observable among adjoining cells. The measurements of root pressure using the root pressure probe showed a sudden, steep drop in the root pressure in response to lowering of the temperature of the bathing solution from 25 degrees C to 8 degrees C. These observations are discussed in the light of the information available on the ultrastructural and biochemical characteristics of the effect of cold exposure in chilling-sensitive plants.

Acclimatization↗

Nitrate reductase regulation in tomato roots by exogenous nitrate: a possible role in tolerance to long-term root anoxia.

The mechanism of nitrate reductase (NR) regulation under long-term anoxia in roots of whole plants and the putative role of nitrate in anoxia tolerance have been addressed. NR activity in tomato roots increased significantly after 24 h of anaerobiosis and increased further by 48 h, with a concomitant release of nitrite into the culture medium. Anoxia promoted NR activation through dissociation of the 14-3-3 protein inhibitor and NR dephosphorylation. After 24 h of anoxia, the total amount of NR increased slightly up to 48 h. However, NR-mRNA levels remained constant between 0 h and 24 h of root anoxia and decreased after 48 h. This is probably due to the inhibition of NR degradation and the accumulation of its native form. NR was slightly dephosphorylated in the absence of oxygen and nitrate. Under anoxia, NR dephosphorylation was modulated by nitrate-controlled NR activity. In addition, the presence of nitrate prevents anoxic symptoms on leaves and delays wilting by 48 h during root anoxia. In the absence of nitrate, plants withered within 24 h, as they did with tungstate treatment, an inhibitor of NR activity. Thus, anoxia tolerance of tomato roots could be enhanced by nitrate reduction.

Adaptation, Physiological↗

Defense-related genes expressed in Norway spruce roots after infection with the root rot pathogen Ceratobasidium bicorne (anamorph: Rhizoctonia sp.).

To study the mechanisms of inducible disease resistance in conifers, changes in transcript accumulation in roots of Norway spruce (Picea abies (L.) Karst.) seedlings exposed to the root rot pathogen Ceratobasidium bicorne Erikss. and Ryv. (anamorph: Rhizoctonia sp.) were monitored by differential display (DD). Because C. bicorne attacks root tips, a desiccation treatment was added to exclude genes induced by pathogen-related desiccation stress. The DD analysis was defined by the use of 11 sets of primers, covering about 5% of the transcriptome. A comparison of gene expression in control, desiccation- and pathogen-stressed roots revealed 36 pathogen-induced gene transcripts. Based on database searches, these transcripts were assigned to four groups originating from spruce mRNA (25 transcripts), rRNA (five transcripts), fungal mRNA (two transcripts) and currently unknown cDNAs (four transcripts). Real-time PCR was applied to verify and quantify pathogen-induced changes in transcript accumulation. Of the 18 transcripts tested, nine were verified to be Norway spruce gene transcripts up-regulated from 1.3- to 66-fold in the infected roots. Four germin-like protein isoforms, a peroxidase and a glutathione S-transferase, all implicated in oxidative processes, including the oxidative burst, were predicted from sequence similarity searches. Seven class IV chitinase isoforms implicated in fungal cell wall degradation and a nucleotide binding site-leucine rich repeat (NBS-LRR) disease resistance protein homologue related to pathogen recognition were identified. Several transcript species, such as the NBS-LRR homologue and the germin-like protein homologues, have not previously been identified as pathogen-inducible genes in gymnosperms.

Amino Acid Sequence↗

Transcriptome profiling in root nodules and arbuscular mycorrhiza identifies a collection of novel genes induced during Medicago truncatula root endosymbioses.

Transcriptome profiling based on cDNA array hybridizations and in silico screening was used to identify Medicago truncatula genes induced in both root nodules and arbuscular mycorrhiza (AM). By array hybridizations, we detected several hundred genes that were upregulated in the root nodule and the AM symbiosis, respectively, with a total of 75 genes being induced during both interactions. The second approach based on in silico data mining yielded several hundred additional candidate genes with a predicted symbiosis-enhanced expression. A subset of the genes identified by either expression profiling tool was subjected to quantitative real-time reverse-transcription polymerase chain reaction for a verification of their symbiosis-induced expression. That way, induction in root nodules and AM was confirmed for 26 genes, most of them being reported as symbiosis-induced for the first time. In addition to delivering a number of novel symbiosis-induced genes, our approach identified several genes that were induced in only one of the two root endosymbioses. The spatial expression patterns of two symbiosis-induced genes encoding an annexin and a beta-tubulin were characterized in transgenic roots using promoter-reporter gene fusions.

Annexins↗

Adhesion of a glass-ionomer root canal sealer to the root canal wall.

Glass-ionomer root canal sealer is commonly used because of its chemical bonding and favorable physical characteristics when bonding to dentin. This study was designed to determine the tensile bond strength of a glass-ionomer sealer (Ketac Endo, Espe, Seefeld, Germany) on root canal walls after pretreatment with different conditioners. Flat inner surfaces of root canal specimens were prepared. The specimens were divided into five groups of 10 teeth, and the groups were conditioned with one of the following smear layer removal solutions: 15% EDTA/NaOCl, 10% polyacrylic acid, 35% phosphoric acid, 6% citric acid, and 5.25% NaOCl as a control. Then the exposed root canal areas were coated with Ketac-Endo. Tensile bonding was measured using a universal testing machine until ultimate failure was obtained. The groups that were treated with phosphoric acid and citric acid showed significantly higher bond strengths than the groups that were treated with 15% EDTA and polyacrylic acid (p < 0.05). Bonding to dentin without smear layer removal (NaOCl group) was too low to be measured in the testing apparatus. Scanning electron microscopy confirmed that phosphoric and citric acids were more effective in removing smear layer than EDTA or polyacrylic acid. The result supported the view that pretreatment with phosphoric acid or citric acid should be used in association with glass-ionomer root canal sealer to achieve the most effective removal of the smear layer and to provide better adhesion.

Acid Etching, Dental↗

Isolation and characterization of a novel ribosome-inactivating protein from root cultures of pokeweed and its mechanism of secretion from roots.

Ribosome-inactivating proteins are N-glycosidases that remove a specific adenine from the sarcin/ricin loop of the large rRNA, thus arresting protein synthesis at the translocation step. In the present study, a novel type I ribosome-inactivating protein, termed PAP-H, was purified from Agrobacterium rhizogenes-transformed hairy roots of pokeweed (Phytolacca americana). The protein was purified by anion- and cation-exchange chromatography. PAP-H has a molecular mass of 29.5 kD as detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its isoelectric point was determined to be 7.8. Yeast (Saccharomyces cerevisiae) ribosomes incubated with PAP-H released the 360-nucleotide diagnostic fragment from the 26S rRNA upon aniline treatment, an indication of its ribosome-inactivating activity. Using immunofluorescence microscopy, PAP-H was found to be located in the cell walls of hairy roots and root border cells. PAP-H was determined to be constitutively secreted as part of the root exudates, with its secretion enhanced by a mechanism mediated by ethylene induction. Purified PAP-H did not show in vitro antifungal activity against soil-borne fungi. In contrast, root exudates containing PAP-H as well as additional chitinase, beta-1,3-glucanase, and protease activities did inhibit the growth of soil-borne fungi. We found that PAP-H depurinates fungal ribosomes in vitro and in vivo, suggesting an additive mechanism that enables PAP-H to penetrate fungal cells.

Amino Acid Sequence↗

A novel short-root gene encodes a glucosamine-6-phosphate acetyltransferase required for maintaining normal root cell shape in rice.

Glycosylation is a posttranslational modification occurring in many secreted and membrane-associated proteins in eukaryotes. It plays important roles in both physiological and pathological processes. Most of these protein modifications depend on UDP-N-acetylglucosamine. In this study, a T-DNA insertional rice (Oryza sativa) mutant exhibiting a temperature-sensitive defect in root elongation was isolated. Genetic and molecular analysis indicated that the mutated phenotype was caused by loss of function of a gene encoding a glucosamine-6-P acetyltransferase (designated OsGNA1), which is involved in de novo UDP-N-acetylglucosamine biosynthesis. The aberrant root morphology of the gna1 mutant includes shortening of roots, disruption of microtubules, and shrinkage of cells in the root elongation zone. Our observations support the idea that protein glycosylation plays a key role in cell metabolism, microtubule stabilization, and cell shape in rice roots.

Acetyltransferases↗

Reciprocal leaf and root expression of AtAmt1.1 and root architectural changes in response to nitrogen starvation.

Nitrogen is an essential macronutrient for plant growth and survival. Here, the temporal and spatial sensing of nitrogen starvation is analyzed in Arabidopsis (Arabidopsis thaliana). The promoter for the high-affinity ammonium transporter, AtAmt1.1, is shown to be a valid indicator for nitrogen status in leaves and roots. An AtAmt1.1-Gal4 transgene using three 5x upstream activating sequence-driven reporters (luciferase, green fluorescent protein, and beta-glucuronidase) facilitated in vivo profiling at the whole-plant and cellular levels. The effects of nitrogen supply, light duration, light intensity, and carbon on the expression of the AtAmt1.1 gene in the roots and aerial tissues are reported. Under nitrogen starvation, high expression is observed in the roots and, under nitrogen-sufficient conditions, high expression is observed in the leaves. This reciprocal regulation of AtAmt1.1 was confirmed by quantitative reverse transcription-polymerase chain reaction, which was also used to quantitate expression of the five other Amt genes in Arabidopsis. Although some of these show tissue specificity (roots or leaves), none exhibit reciprocal regulation like the AtAmt1.1-encoded high-affinity transporter. This robust reciprocal expression suggests that Arabidopsis undergoes rapid resource reallocation in plants grown under different nitrogen supply regimens. Ultimately, nitrogen starvation-mediated reallocation results in root architectural restructuring. We describe the precise timing and cellular aspects of this nitrogen limitation response.

Arabidopsis↗

Quadrant root planing versus same-day full-mouth root planing. I. Clinical findings.

OBJECTIVES: The aim of this study was to test the hypothesis that same-day full-mouth scaling and root planing (FM-SRP) resulted in greater clinical improvement compared to quadrant scaling and root planing (Q-SRP) in chronic periodontitis patients over a period of 6 months. MATERIAL AND METHODS: Forty patients were recruited into this study. Subjects were randomised into two groups. The FM-SRP group received full-mouth scaling and root planing completed within the same day, while the Q-SRP group received quadrant root planing at 2-weekly intervals over four consecutive sessions. Whole-mouth clinical measurements were recorded with a manual periodontal probe at baseline (BAS) and at reassessment 1 (R1) (approximately 6 weeks after the completion of therapy), and at reassessment 2 (R2) (6 months after the initiation of therapy). Selected site analyses were performed on the deepest site in each quadrant before and after therapy (R1 and R2) and clinical indices were recorded with an electronic pressure sensitive probe. In addition, during the active phase of treatment clinical data were collected at 2-weekly intervals from the remaining untreated quadrants in the Q-SRP group only. RESULTS: Both therapies resulted in significant improvements in all clinical indices both at R1 and R2. A continuous clinical improvement was seen for both treatment groups during the experimental period, which reached peak levels at 6 months (DeltaPD=1.8 mm, DeltaCAL=1.1 mm, p<0.001; PD: pocket depth; CAL: clinical attachment level). The selected-site analysis revealed no significant differences in any clinical index between the two treatment groups at R2 (DeltaPD=2.8 mm, DeltaRAL=1.1 mm; RAL: relative attachment level). At the selected sites, the analysis of the deep pockets (>7 mm) showed a significantly greater gain in RAL for the FM-SRP group compared to the Q-SRP group at R2 (p<0.05). The results of this analysis however, should be interpreted with care due to the small number of deep pockets. Data from the Q-SRP group provided an insight into how treated and untreated quadrants responded during the initiation of plaque control measures. There were significant reductions in PD, suppuration (SUP), modified gingival index (MGI) and plaque index (PI) in the remaining untreated quadrants in the Q-SRP group during the initial phase of treatment (p<0.05), while minimum changes in RALs and bleeding on probing (BOP) occurred. Nevertheless, the improvement in PD was clearly inferior to that seen after scaling and root planing. CONCLUSION: Following both therapeutic modalities, there were marked clinical improvements at both R1 and R2 (6 months) from baseline. The current study, in contrast to previous findings, failed to show that FM-SRP is a more efficacious periodontal treatment modality compared to Q-SRP. However, both modalities are efficacious and the clinician should select the treatment modality based on practical considerations related to patient preference and clinical workload.

Adult↗

Quadrant root planing versus same-day full-mouth root planing.

OBJECTIVES: The aim of this study was to determine whether same-day full-mouth scaling and root planing (FM-SRP) and quadrant scaling and root planing (Q-SRP) resulted in variations in the systemic humoral immune response dynamics (antibody titres and avidity) during active treatment and 3 and 6 months post-therapy. MATERIALS AND METHODS: Forty patients with chronic periodontitis were recruited into this study. Subjects were randomised into two groups and received either scaling and root planing quadrant by quadrant at 2-weekly intervals (Q-SRP group) or same-day full-mouth scaling and root planing (FM-SRP group). Clinical measurements and serum samples were obtained at baseline and approximately 6 weeks after the last clinical intervention (R1) and 6 months after the initiation of therapy (R2). Furthermore, serum samples were obtained from each patient undergoing therapy (Q-SRP and FM-SRP) at 3 bi-weekly instances so as to determine the short-term effects of each session of scaling and root planing on the dynamics of the humoral immune response. Serum antibody titre was assayed by enzyme-linked immunosorbent assay (ELISA) and antibody avidity was measured by thiocyanate dissociation against five putative periodontal pathogens: Porphyromonas gingivalis; Actinobacillus actinomycetemcomitans; Prevotella intermedia; Treponema denticola and Bacteroides forsythus. RESULTS: Both therapies resulted in similar antibody titre reductions against the majority of the organisms tested and although there was a distinct trend for antibody avidity to increase following therapy, this was not found to be statistically significant, reflecting marked inter-individual variation. In addition, no evidence emerged from this study to support increased antibody titres following the active phases of both treatment approaches due to an inoculation effect. Nevertheless, significant short-term increases in antibody avidity to most test bacteria were noted for both treatment strategies. CONCLUSION: Both therapies were associated with a reduction in antibody titres and an increase in the binding ability or avidity of antibodies, but there was a marked inter-subject variability and statistical significance was reached for only some of the test bacteria. No significant differences in the humoral antibody dynamics were found between the two treatment approaches.

Adult↗

Survival, regeneration and functional recovery of motoneurons in adult rats by reimplantation of ventral root following spinal root avulsion.

We investigated the functional recovery of motoneurons after reimplanting an avulsed ventral root in a rat model of traction injury. The eighth cervical root (C8) was avulsed by controlled traction and immediately reimplanted to the spinal cord. Spinal nerves from neighbouring segments (C5, C6, C7 and T1) were ligated and cut. After 12 or 20 weeks, the survival, regeneration and functional recovery of spinal motoneurons were evaluated by Nissl staining, retrograde labelling of motoneurons, NOS histochemistry, histological examination of muscle and nerve-muscle junction, electromyography and behavioural observation. In the control animals, about 14% or 11% of spinal motoneurons survived 12 or 20 weeks postinjury, respectively. By contrast, in animals with ventral root reimplantation, 62% and 55% of motoneurons survived at 12 or 20 weeks postinjury, respectively. Retrograde labelling and histological examination indicated that about 90% of the surviving motoneurons in the C8 segment regenerated axons into the reimplanted ventral root. Staining the muscles with silver and cholinesterase revealed new motor endplates in the reinnervated muscle. Functionally significant electromyographic responses in flexor digitorum superficialis and flexor carpi radialis were observed in experimental animals; however, the average latency of the motor action potentials was greater than normal control. The grasping test showed functional recovery of finger flexors and median nerve. In conclusion, our results indicate that spinal motoneurons can regenerate axons through reimplanted roots and reinnervate muscles to recover partial function.

Animals↗

Healing of 400 intra-alveolar root fractures. 1. Effect of pre-injury and injury factors such as sex, age, stage of root development, fracture type, location of fracture and severity of dislocation.

This retrospective study consisted of 400 root-fractured, splinted or non-splinted incisors in young individuals aged 7-17 years (mean = 11.5 +/- 2.7 SD) who were treated in the period 1959-1995 at the Department of Pediatric Dentistry, Eastman Dental Institute, Stockholm. Four hundred of these root fractures were diagnosed at the time of injury; and 344 teeth were splinted with either cap-splints, orthodontic appliances, bonded metal wires, proximal bonding with composite resin or bonding with a Kevlar or glass fiber splint. In 56 teeth, no splinting was carried out for various reasons. In the present study, only pre-injury and injury factors were analyzed. In a second study, treatment variables will be analyzed. The average observation period was 3.1 years +/- 2.6 SD. The clinical and radiographic findings showed that 120 teeth out of 400 teeth (30%) had healed by hard tissue fusion of the fragments. Interposition of periodontal ligament (PDL) and bone between fragments was found in 22 teeth (5%), whereas interposition of PDL alone was found in 170 teeth (43%). Finally, non-healing, with pulp necrosis and inflammatory changes between fragments, was seen in 88 teeth (22%). In a univariate and multivariate stratified analysis, a series of clinical factors were analyzed for their relation to the healing outcome with respect to pulp healing vs. pulp necrosis and type of healing (hard tissue vs. interposition of bone and/or PDL or pulp necrosis). Young age, immature root formation and positive pulp sensibility at the time of injury were found to be significantly and positively related to both pulpal healing and hard tissue repair of the fracture. The same applied to concussion or subluxation (i.e. no displacement) of the coronal fragment compared to extrusion or lateral luxation (i.e. displacement). Furthermore, no mobility vs. mobility of the coronal fragment. Healing was progressively worsened with increased millimeter diastasis between fragments. Sex was a significant factor, as girls showed more frequent hard tissue healing than boys. This relationship could possibly be explained by the fact that girls experienced trauma at an earlier age (i.e. with more immature root formation) and their traumas were of a less severe nature. Thus, the pre-injury or injury factors which had the greatest influence upon healing (i.e. whether hard tissue fusion or pulp necrosis) were: age, stage of root development (i.e. the size of the pulpal lumen at the fracture site) and mobility of the coronal fragment, dislocation of the coronal fragment and diastasis between fragments (i.e. rupture or stretching of the pulp at the fracture site).

Adolescent↗

Maxillary second premolar with three roots and three separate root canals--case reports.

Aberrations in root canal systems are a commonly occurring phenomenon. Knowledge of the basic root canal anatomy and its variation is necessary for successful completion of endodontics. Maxillary second premolars usually have one root and one canal. The occurrence of these teeth having three roots and three canals is very rare. Three such cases of maxillary second premolar with three roots and three canals are presented here.

Adult↗

Amelioration of the salt-stressed root growth of rice and normalization of the Na+ distribution between the shoot and root by (S)-alpha-methylbenzyl-2-fluoro-4-methylphenylurea.

Optically active alpha-methylbenzyl phenyl ureas (MBPUs) show diverse plant physiological properties. Experiments were conducted to evaluate the salt-stress response of just-germinated rice seedlings supplemented with the S-enantiomer of MBPUs by assessing the growth and Na+ content. This study indicates that S-MBPUs served as a unique stress reliever for just-germinated young seedlings of rice injured by salinity. NaCl severely affected the root growth of rice seedlings. Concomitant treatment with S-MBPUs effectively ameliorated the growth inhibition of rice by NaCl. Glycine betaine (GB) did not act as a reliever of the NaCl stress. The addition of S-alpha-methylbenzyl 2-fluoro-4-methylphenyl urea (7, denoted as S-FM) to the saline medium ameliorated not only the root growth but also the protein content and dry weight of roots depending upon its concentration. The protein content, Na+ content and growth rate were correlated to each other with a positive relationship. The Na+ distribution ratio (S/R(Na+)) between the shoot and root increased with increasing concentration of NaCl when added alone, viz. with increasing growth reduction. A concomitant treatment with S-FM (7), however, resulted in the S/R(Na+) value becoming smaller with growth amelioration. This indicates that S-FM (7) controlled the translation of Na+ from the roots to shoots. S-FM (7) would have influenced some inherent functions connected with the Na+ behavior in the rice plant, although details of the mechanism for normalization of the S/R(Na+) ratio are still not clear.

Oryza↗

Repair of cervical nerve roots proximal to the root ganglia. An experimental study in sheep.

An experimental model was established to investigate the possibility of repairing cervical nerve roots damaged above the dorsal root ganglion, as occurs in traction injuries of the brachial plexus. In four sheep the C6 root was divided and repaired within the dura using freeze-thawed muscle grafts. Recovery was assessed after eight months by electrophysiology and histology. Action potentials were recorded distal to the grafts in all four sheep, indicating regeneration of motor fibres. Histological examination showed regenerated fibres in the ventral roots below the grafts in all cases. These fibres could be traced distally to the brachial plexus. There was no evidence of recovery of dorsal roots.

Action Potentials↗