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PubMed2006

Factors related to apical root resorption of maxillary incisors in orthodontic patients.

UNLABELLED: THE MAIN OBJECTIVE of the study was to determine the extent of external apical root resorption at the end of orthodontic treatment and to identify the possible pre-treatment and treatment factors that would allow to predict the possible incidence of root resorption before the start of treatment. PATIENTS AND METHODS: Panoramic radiographs of 75 patients that had been treated with full fixed appliances were used to assess apical root resorption in maxillary incisors. The degree of root resorption was measured in millimetres and the scale of Shape was used. RESULTS: The results showed that the resorption in the maxillary incisors is on the average 1.5 mm, the severe resorption was seen in 2.6% of patients. The worst resorption was seen in teeth with abnormal root shape. There were no differences in the severity of root resorption when comparing males and females as well as children and adults. Increased overjet, overbite and extraction therapy were not associated with greater root resorption. Duration of treatment and length of treatment time with rectangular wires were associated with greater root resorption. Patients wearing composite brackets with a metal slot had more resorption than patients wearing metal brackets. CONCLUSION: Pre-treatment risk indicator for root resorption was abnormal root shape. Risk indicators for root resorption that were related to treatment procedures included length of treatment time with rectangular wires, duration of treatment and treatment with composite brackets with a metal slot.

Adolescent↗
PubMed1991

Radiographic observations on root resorption in the primary dentition.

In order to construct standardized charts for root resorption in the primary dentition of Japanese children, we investigated the stages of resorption (1/4, 1/2 and 3/4 of the root) based on the criterion of Fanning, et al. using 11,167 panoramic radiographs (5,759 of boys and 5,408 of girls). The following information was obtained. 1) The root resorption for a tooth on one side was the same as for its counterpart on the other side regardless of differences in sex or arch. 2) The average age for each root resorption stage was lower in girls than in boys regardless of differences in sex or arch. 3) The average age for each root resorption stage was lower in the mandible than in the maxilla for every tooth. 4) In the maxilla, the period between 1/4 to 3/4 resorption of the root was greater in the primary molars than in the primary anterior teeth. However, the opposite was true in the mandible. 5) Although no difference was observed between the maxilla and the mandible in the resorption period for the primary incisors and canines, the resorption time for the primary molars was greater in the maxilla than in the mandible. 6) When the relationship was observed between the resorption stages for each tooth and the calcification stages for the corresponding successional permanent tooth. a) With the exception of the maxillary and mandibular canines, the average age for 1/4 resorption of the primary root corresponded to the period between completion of the permanent crown and initial root formation of the successional permanent tooth. b) With the exception of the maxillary and mandibular canines, and the mandibular second premolars, the average age for 3/4 resorption of the primary root corresponded to the period between 1/4 and 1/2 formation of the root of the successional permanent tooth. From these results, standardized charts were constructed for the resorption of the roots of primary teeth in Japanese children. These standardized charts are useful in daily clinical practice in such areas as endodontic treatment of primary teeth and orthodontics.

Adolescent↗
PubMed1990

[Experimental study on a mechanical root canal enlargement].

It is difficult for us to enlarge a root canal by using hand-instruments in a molar tooth, so we experimented by using mechanical equipment. We examined the human extracted premolar which we had preserved in physiological saline solution by using a speculative root canal enlarging machine. Then we observed the time and condition of enlarging root canal by X-ray. After slicing off, we examined with our eyes and with an electronic microscope. Afterward, we compared hand-instruments with the enlarging machine. As the results of this experiment; 1. Time by hand filing instruments took three or four times to make a root canal enlargement by a speculative enlarging machine. 2. After enlarging a root canal, we made a root canal filling. Observing them by X-ray and ground specimen, we recognized a good result in the root canal enlargement and in the condition of the root canal filling. 3. Observing the figure by electronic microscope, in the case of using a speculative machine, we found that the slicing aspects of dentin which had been enlarged by root canal were thoroughly smoothed in the center part of the root canal, but it was not smoothed in the root apex region. 4. It had a tendency to remain part of the cutting dentin near the apical area both by using hand cutting instruments and by using a speculative machine.

Bicuspid↗
PubMed1989

Shape and number of the roots of the permanent molar teeth.

One hundred ninety-eight mandibular first molars, 198 mandibular second molars, and 122 mandibular third molars, extracted from 99 Indian skulls were examined for the number of dental roots. The number of mandibular molar roots is increased by the appearance of the distolingual root, accessory lingual root, and bifurcation of the mesial root. The bifurcation of the mesial root was investigated in teeth in which it was more than 1/3 and less than 1/3 (apical bifurcation) of the root length. The following results were obtained. The numbers of the roots including apical bifurcation of the mesial root were 2, 3 and 4 in 72.7%, 26.8% and 0.5%, respectively, of the first molars; 1, 2 and 3 in 17.7%, 76.8% and 5.6%, respectively, of the second molars; and 1, 2 and 3 in 16.4%, 77.1% and 5.8%, respectively, of the third molars. The numbers of dental roots excluding apical bifurcation of the mesial root were 2 and 3 in 99.0% and 1.0%, respectively, of the first molars; 1, 2 and 3 in 17.7%, 81.8% and 0.5%, respectively, of the second molars; and 1, 2 and 3 in 16.4%, 77.1% and 5.8%, respectively, of the third molars.

Asian People↗
PubMed1995

Orthodontic tooth movement and root resorption with special reference to force magnitude and duration. A clinical and histological investigation in adolescents.

The purpose of orthodontic treatment is to move teeth as efficiently as possible with least damage to teeth and their supporting tissues. Root resorption may occur as an unwanted side effect and may in some instances jeopardize an otherwise successful treatment. The general aim of this series of clinical investigations was to study the association between applied force, achieved tooth movement and related root resorptions. In 144 adolescents, the maxillary first or second premolar was buccally moved with a fixed orthodontic appliance. The variables studied were duration, magnitude and type of force. Moreover, both the occurrence of orthodontically induced root resorptions and the reparative potential were investigated in histological preparations of the teeth. When a continuous force of a clinically relevant magnitude (50 cN approximately 50 g) was applied, tooth movement increased gradually over time. Root resorptions were recorded in all test teeth but 4 (93%). After 3 weeks a few teeth revealed root resorptions extending half way to the pulp or more in the apical third of the root. No association was found between root resorptions and tooth movement. Doubling the force magnitude (100 cN approximately 100 g) affected neither the tooth movement nor the severity of root resorptions. However, when the force was increased 4 times (200 cN approximately 200 g), tooth movement increased 50% but still with no significant increase in the occurrence or severity of root resorptions. Tooth movement was achieved more efficiently with a continuous force than with an interrupted type of force of the same magnitude (50 cN). Root resorptions, though, did not seem to be affected differently by the two types of forces. Reduction of all types of applied forces was considerable, about 25-30%, already within one week. Repair with secondary cementum was recorded almost 3 times more often after 8 weeks (75%) of retention than after 1 week (28%). Irrespective of magnitude and type of force, large individual variations were observed regarding tooth movements and root resorptions as well as their reparative potential. The possible clinical consequences of the results obtained are discussed with regard to cost-benefit effects, convenience to the patient and risk of complications.

Adolescent↗
PubMed1994

[Classification and surgical treatment of lumbosacral nerve root anomalies].

In this paper 12 cases of lumbosacral nerve-root anomalies proved on operations were reported. Two roots with a common conjoined origin entering the common intervertebral foramen separately were seen in two cases; two roots arising respectively from the lateral and ventral sides of the dural sac at the level of upper margin of the pedicle, in which one ran transversely into the foramen and another obliquely ran downward, in one case; two roots with closely adjacent origins, in which one ran transversely into the foramen at the level of upper margin of the pedicle and another obliquely ran downward, in four cases; a single root with abnormally large whereas the adjacent root with abnormally small, in five cases. We proposed a classification method for the sake of appropriate surgical program, which assorted the anomalies into three types: (I) General volume of nerve roots in the spinal canal or nerve-root canal abnormally increased, either the diameter of a single root increases or two roots entered the common. foramen; (II) The origin and course of two roots were anomalous; (III) Combination of I and II.

Adult↗
PubMed1993

Prevalence of root caries in a Japanese adult population aged 20-59 years.

The purpose of the present study was to investigate the prevalence of root caries in an adult population in Japan. A total of 770 company employees aged 20-59 were examined in 1990. The subjects were all dentate and had 27.2 present teeth on the average. The proportion of gingival recession in this population ranged from 20.1% for the 20-29 year old group to 75.2% for the 50-59 year old group, with an average of 44.0%. In the present study, 3.2% of the subjects showed one or more active root caries. The prevalence of active root caries ranged from 0.4% at age 20-29 to 7.1% at age 50-59. The proportion of persons with active root caries and/or root fillings ranged from 1.3% at age 20-29 to 36.3% at age 50-59. The percentage of subjects with active and/or inactive caries and/or root fillings varied from 3.1% at age 20-29 to 43.4% at age 50-59. The prevalence of active root caries in the subjects at risk (with gingival recession) was 7.4% on the average and ranged from 2.2% at age 20-29 to 9.4% at age 50-59. The percentage of persons with active root caries and/or root fillings in the subjects at risk ranged from 6.7% at age 20-29 to 48.2% at age 50-59. The mean number of teeth with active root lesions was 0.09 per person, and the mean number of teeth with root fillings was 1.25 at age 50-59.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Root surface caries of denture wearers in middle-aged and elderly people.

With an increasing number of elderly people retaining natural dentition, the number of exposed root surfaces and root surface caries is increasing. A total of 100 people, aged from 38 to 86, were examined for exposed root surfaces and root surface caries. Denture wearers and non-denture wearers were examined. The following results were obtained; 1. The percentages of exposed root surfaces were significantly higher (P < 0.05) in the 60's and 70's age groups. Root surface caries showed a tendency to increase until people were in their 60's. 2. Denture wearers had more exposed root surfaces (P < 0.05) and were more likely to have root surface caries than non-denture wearers. Denture wearers showed a tendency to have more severe grades of root surface caries than non-denture wearers. 3. Concerning denture wearers, there were not significant differences in the percentages of exposed root surfaces of buccal and proximal surfaces facing edentulous space. However, proximal surfaces facing edentulous space were more prone to root surface caries than buccal surfaces (P < 0.05).

Adult↗
PubMed2000

Study on removal effects of filling materials and broken files from root canals using pulsed Nd:YAG laser.

OBJECTIVES: The aims of this study were to investigate the capability of removing the filling materials or broken files from root canals with pulsed Nd:YAG laser irradiation at three parameters, and to evaluate the temperature rises on root surfaces and morphological changes of root canal walls in vitro. SUMMARY BACKGROUND DATA: There has been no report on removing the filling materials and broken instruments from root canals with laser irradiation. MATERIALS AND METHODS: Thirty-six extracted human incisors were divided into two groups of 18 each. Eighteen root canals were shaped and obturated with gutta-percha and root canal sealer. In another 18 specimens, 3-mm long fractures of files were performed intentionally during root canal preparation. A pulsed Nd:YAG laser irradiation was performed repeatedly at three parameters of 1, 2, and 3 W to remove the filling materials or file fragments. Temperature rises on root surfaces during laser irradiation were measured by thermography, and the remaining of obturated materials and morphological changes of root canal walls were evaluated by stereoscopy and scanning electron microscopy. RESULTS: In more than 70% of the teeth, the obturated materials were completely removed by laser, and in more than 55% of the teeth, the broken files were successfully removed. Temperature rises ranging from 17 degrees C to 27 degrees C were measured from 6 to 11 repeated times. CONCLUSION: These results demonstrated that a pulsed Nd:YAG laser irradiation has the capability of removing the obturated materials in root canals and is useful for removing the broken files in same if the counter-measure reducing the temperature rise is performed.

Dental Pulp Cavity↗
PubMed1991

Effect of immediate calcium hydroxide treatment and permanent root-filling on periodontal healing in contaminated replanted teeth.

The effect of immediate permanent root-filling and immediate intracanal calcium hydroxide treatment on experimentally contaminated and necrotized periodontal membranes (PDM) in avulsed and subsequently replanted monkey teeth was studied. Almost the entire root surface in the non-endodontically treated control teeth were covered with inflammatory resorption. A significant shift towards ankylosis not associated with root resorption (greater than 80% of the total root surface area) was noted following calcium hydroxide treatment. About two thirds of the root surfaces from the teeth with permanent root fillings showed surface resorptions or ankylosis preceded by root resorption. The root surface area which would have been covered by inflammatory resorption, unless endodontic treatment had been implemented, were instead predominantly covered by either surface resorption (permanent root filling) or ankylosis (calcium hydroxide treatment). Ankylosis compared with surface resorption may in the long term lead to progressive loss of root substance due to replacement resorption. It was concluded that calcium hydroxide may be an excellent initial intracanal treatment in teeth with healthy PDM, but care should be taken not to risk unnecessary development of ankylosis by prolonged treatment of teeth with compromised PDM.

Alveolar Process↗
PubMed1990

Frequent spontaneous deletions of Ri T-DNA in Agrobacterium rhizogenes transformed potato roots and regenerated plants.

The presence of T-DNA was examined by Southern blot analysis in 16 regenerated shoot lines derived from 6 Agrobacterium rhizogenes-transformed root clones of Solanum tuberosum L. cv. Bintje. TR-DNA, present in regenerated shoot lines from 3 out of 6 root clones was correlated with the presence of opines. One root clone produced opines up to 2.5 years of subculture. However, plant regeneration from and prolonged subculturing of this root clone resulted in loss of opine synthesis, caused by deletion of TR-DNA. TL-DNA inserted at 1 to 5 independent loci was found in 14 of the 16 shoot lines. Surprisingly, 1 to 2 additional insertions next to similar insertions of TL-DNA were found in shoot lines from the same root clone (named 'sister' shoot lines) in 2 out of 4 root clones. Nevertheless, this did not result in gross phenotypic variation between sister shoot lines. Another root clone regenerated 1 shoot line with an Ri phenotype, containing 1 insertion of TL-DNA, and 2 shoot lines with a normal Bintje phenotype without TL-DNA. The 5th root clone showed no difference between sister shoot lines and the 6th root clone produced only 1 shoot line. We conclude that during prolonged root culture and during shoot regeneration from root clones deletion of TL- and TR-DNA insertions can occur. The significance of the frequency of deletion of T-DNA of the Ri plasmid is discussed.

Chromosome Deletion↗
PubMed1995

Magnetic resonance imaging findings of the lumbar root pathway in patients over 50 years old.

In patients with degenerative disease of the lumbar spine, stenosis not only in the entrance zone but also in the mid- and exit zones of the nerve root pathway can occur. With the development of magnetic resonance imaging (MRI), it has become easier to assess stenosis of the root pathway, especially in the mid- and exit zones. T1-weighted sagittal images in the lateral facet plane show the state of the exit zone. I studied the incidence of severe exit-zone stenosis of L3-5 roots in 45 patients aged over 50 years 15 in their fifties, 15 in their sixties, and 15 in their seventies) by MRI and assessed the results on the basis of age, intervertebral disc degeneration, and disc height. I also studied the relationship between clinical symptoms and severe stenosis in both entrance and exit zones of the L4 and L5 roots. The incidence of severe exit-zone stenosis at the L3 root was < 20% at all ages. On the other hand, L4 and L5 nerve root stenosis increased with age and severe stenosis affected 70% of L4 roots and 80% of L5 roots in patients in their seventies. The incidence of deformation or disappearance of the dorsal root ganglion (DRG) was 10% or less at L3 and L5 roots, while it was 10% at L4 root.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Aflatoxin-induced alterations in Glycine max, cv. 'Essex' root cell membrane protein content.

Aflatoxins (AFTs) are hepatocarcinogens, mutagens, teratogens and toxins. Isolates of AFTs-producing strains of Aspergillus flavus can grow upon both autoclaved soybeans and to a lesser extent field-grown beans. Besides inhibiting the elongation of excised, in vitro cultured soybean roots, the AFTs can impair the roots' ability to remove [14C]-leucine from a culture medium and to incorporate the amino acid into acid-insoluble, cytoplasmic protein. In this connection, exogenous AFTs once taken-up and compartmentalized by the excised roots can reduce the acid-insoluble protein content of what appears to be a non-enriched plasmalemma fraction. Here, we report a combined biochemical and microscopical attempt to determine whether the protein reduction occurs throughout the excised, in vitro-cultured root and whether the plasmalemma proteins which are affected by AFTs can be both solubilized and characterized. Histochemistry of Carnoy-fixed roots revealed a reduction in Ninhydrin-Schiff-stainability throughout the AFTs-treated root. Transmission electron microscopy of 80 000 X g pellets derived from homogenates of both non-treated (NT) and treated (T) roots provided further evidence to our previously reported marker enzyme analyses for the occurrence of the plasmalemma in the 80 000 X g pellet. Treatment of the latter with the Laemmli SDS procedure released greater than 85% of the protein associated with the pellets obtained from homogenates of either NT or T roots. Gel permeation chromatography on Biogel-100 of released proteins from 80 000 X g pellets of both NT and T roots yielded both void volume and retarded peaks. Both the amplitude and the quantities of protein recovered within the void volume peak were less within the void volume of the t than the NT root. Polyacrylamide tube gel electrophoresis of G-100 void volume peaks of chromatographed, SDS-released proteins from the pellets revealed quantitative but not qualitative differences in Coomassie Blue-gel staining patterns between T and NT roots. These results suggest that the SDS methods which we employed could solubilize the 80 000 X g pellet proteins but that combined gel permeation chromatography and tube gel electrophoresis were not sensitive enough to reveal whether AFTs could alter the types of proteins associated with the 80 000 X g pellet (purported plasmalemma).

Aflatoxins↗
PubMed1997

External and Internal Root Colonization of Maize by TwoPseudomonas Strains: Enumeration by Enzyme-Linked Immunosorbent Assay(ELISA)

Maize root colonization by two fluorescentPseudomonas strains M.3.1. and TR335, isolated respectively frommaize and tomato roots, were studied in hydroponic conditions. Each bacteriumwas inoculated separately, and three different colonization areas werestudied: nutrient solution, rhizoplane, and endorhizosphere. The twoPseudomonas strains established large rhizosphere populations, andrhizoplane colonization of the entire root system was similar for bothstrains. However, strain M.3.1. colonized the endorhizosphere moreefficiently than strain TR335. Seminal root cuttings from the tip to the seedallowed the assessment of colonization of three different root areas (i.e.,root cap and elongation area, root-hair zone, and mature zone). Rhizoplanecolonizations of all these three areas by M.3.1. were significantly the same,whereas strain TR335 colonized the rhizoplane of the root cap and elongationarea more actively than the root-hair zone and mature zone. Population sizeof the strain M.3.1. in the internal tissue of these areas was greater thanthat of strain TR335. Co-inoculations of the two strains indicated astimulation of the population size of strain M.3.1. regardless of root areastudied, whereas population size of strain TR335 remained unchanged. Theseresults demonstrated that external and internal maize root tissues werecolonized to a greater extent by a strain isolated from a maize rhizospherethan by one isolated from another rhizosphere.

Journal Article↗
PubMed1999

Effects of NH(4)(+), NO(3)(-) and HCO(3)(-) on apoplast pH in the outer cortex of root zones of maize, as measured by the fluorescence ratio of fluorescein boronic acid

A fluorimetric ratio technique was elaborated to measure apoplastic pH in the outer root cortex of maize (Zea mays L.) grown hydroponically. A newly synthesized fluorescent probe, fluorescein boronic acid (pK(a) = 5.48), which covalently binds to the cell wall of the outer cell layers, was used. Under conditions of saturating ion concentrations the apoplastic pH was determined along the root axis ranging from 1 to 30 mm behind the root tip. Apoplastic pH was recorded for root segment areas (1 mm(2)), and pH values of high statistical significance were obtained. With an external solution of pH 5, the apoplastic pH was about pH 5.1 in the division zone, between pH 4.8 and 4.9 in the elongation region and about pH 4.9 in the root hair zone. At an external pH of 8.6, the difference between the external pH and the apoplastic pH was considerably more, with a pH of 5.2-5.3 in all root zones. Addition of 1 mM NH(4)(+) caused a small apoplastic pH decrease (0.05 of a pH unit) in all root zones. Apoplastic alkalization upon application of 6 mM NO(3)(-) was highest (0.3 of a pH unit) in the zone where root hairs emerge; in the division and early elongation zones, apoplastic pH increased only transiently. In the presence of 10 mM HCO(3)(-), NO(3)(-) elicited a higher and persistent alkalization (0.06-0.25 of a pH unit) in all root zones. Application of fusicoccin reduced apoplastic pH from 4.85 to 4.75 in the elongation zone, while inhibition of the H(+)-ATPase with vanadate alkalized the apoplast in the root hair zone from pH 5.4 to 5.6. The observed pH differences along the root axis upon differential N supply and application of HCO(3)(-) provide evidence that this new pH technique is a useful tool with which to measure apoplastic pH, and in future may permit measurements at microsites at the cell level by use of microscope imaging.

Journal Article↗
PubMed2006

Immunohistochemical, histochemical and radioassay analysis of nitric oxide synthase immunoreactivity in the lumbar and sacral dorsal root ganglia of the dog.

In this study, immunohistochemistry for neuronal nitric oxide synthase (bNOS-IR), nicotinamide adenine dinucleotide phosphate diaphorase histochemistry (NADPHd) and nitric oxide synthase radioassay were used to study the occurrence, number and distribution pattern of nitric oxide synthesizing neurons in the lumbar (L1-L7) and sacral (S1-S3) dorsal root ganglia of the dog. Nitric oxide synthase immunolabelling was present in a large number of small- (area <1,000 microm(2)) and medium-sized (area 1,000-2,000 microm(2)) as well as in a limited number of large-sized (area >2000 microm(2)) neurons. Although neuronal nitric oxide synthase immunolabelling and histochemical staining provided intense staining of multiple small- and medium-sized neurons in all lumbar and sacral dorsal root ganglia, immuno-labelled or histochemically stained somata exhibited little topographic distribution in individual dorsal root ganglia. Great heterogeneity was noticed in the immunolabelling of medium-sized nitric oxide synthase immunopositive neurons ranging from lightly immuno-labelled somata to heavily immunoreactive ones with completely obscured nuclei. Both staining procedures proved to be highly effective in visualizing intraganglionic fibers of various diameters. In general, the largest fibers revealed at the peripheral end of lumbar and sacral dorsal root ganglia were larger, 6.49-9.35 mum in diameter, while those running centrally and proceeding into the dorsal roots were about 30% reduced, ranging between 5.32 and 8.67 microm in diameter. Peripherally, the occurrence of nitric oxide synthase detected in axonal profiles, and confirmed histochemically, in the specimens of the femoral and sciatic nerves, is the first indication of the presence of nitric oxide synthase in the peripheral processes of somata located in L4-S2 dorsal root ganglia. Large and thin central nitric oxide synthase immunoreactive processes of L1-S3 dorsal root ganglion neurons segregate shortly before entering the spinal cord, the former making a massive medial bundle in the dorsal root accompanied by a slim lateral bundle penetrating Lissauer's tract. Quantitative assessment of the distribution of bNOS-IR and/or NADPHd-stained neurons showed a peculiar pattern in relation to spinal levels. Apparent incongruity was found in the total number of NADPHd-stained versus bNOS-IR neurons, demonstrating a clear prevalence of small bNOS-IR somata in all lumbar ganglia, while medium-sized NADPHd-stained somata clearly prevailed all along the rostrocaudal axis with a peak in L5 ganglion. While the number of small bNOS-IR neurons clearly outnumbered NADPHd-stained and NADPHd-unstained somata in S1-S3 ganglia, an inverse relation appeared comparing the total number of medium-sized NADPHd-stained and NADPHd-unstained somata compared with the number of moderate and intense bNOS-IR neurons. Densitometry of bNOS-IR and NADPHd-stained neurons in lumbar and sacral ganglia revealed two distinct subsets of densitometric profiles, one relating to more often found medium-sized bNOS immuno-labelled and the other, characteristic for moderately bNOS immunoreactive somata of the same cell size. Considerable differences in catalytic nitric oxide synthase activity, determined by conversion of [(3)H]arginine to [(3)H]citrulline were obtained in lumbosacral dorsal root ganglia all along the lumbosacral intumescence, the lowest (0.898+/- 0.2 dpm/min/microg protein) being in the L4 dorsal root ganglion and the highest (4.194+/-0.2 dpm/min/microg protein) in the S2 dorsal root ganglion.

Animals↗
PubMed1983

Echocardiographic assessment of cardiovascular abnormalities in the Marfan syndrome. Comparison with clinical findings and with roentgenographic estimation of aortic root size.

Echocardiographic abnormalities of the mitral valve and aortic root were compared with auscultatory findings and with assessment of aortic root size by chest roentgenography in 61 patients with the Marfan syndrome. Echocardiography was more sensitive than physical examination in detecting valvular and aortic root abnormalities. Although physical examination revealed findings of mitral valve disease and/or of aortic regurgitation in 52 percent of patients (mitral valve disease in 44 percent and aortic regurgitation in 23 percent), echocardiography detected abnormalities of the mitral valve and/or aortic root in 82 percent of patients (mitral valve prolapse in 57 percent and aortic root enlargement in 69 percent). Prevalence of mitral valve prolapse was approximately equal in male and female patients, whereas aortic root enlargement was more frequent in males (83 percent) than in females (50 percent). Echocardiographically detected aortic root enlargement was frequently not apparent on chest x-ray films. Indeed, five patients with markedly increased aortic root diameters (ranging from 6.0 to 7.9 cm) had no evident enlargement of the aortic root on routine chest x-ray films. In all four of those patients who had angiographic and/or pathologic correlations, confirmation of marked aortic root dilatation was obtained. There are limitations to echocardiographic evaluation of the presence and severity of underlying cardiovascular disease in patients with the Marfan syndrome. Mitral valve disease may not be detected, especially in patients with left ventricular dilatation. In addition, due to anteroposterior compression of the left atrium by the enlarged aorta, left atrial size may be underestimated in patients with aortic root enlargement.

Adolescent↗
PubMed1994

Changing root system architecture through inhibition of putrescine and feruloyl putrescine accumulation.

Plant roots provide anchorage and absorb the water and minerals necessary for photosynthesis in the aerial parts of the plant. Since plants are sessile organisms, their root systems must forage for resources in heterogeneous soils through differential branching and elongation [(1988) Funct. Ecol. 2, 345-351; (1991) Plant Roots: The Hidden Half, pp. 3-25, Marcel Dekker, NY]. Adaptation to drought, for instance, can be facilitated by increased root growth and penetration. Root systems thus develop as a function of environmental variables and the needs of the plant [(1988) Funct. Ecol. 2, 345-351; (1986) Bot. Gaz. 147, 137-147; (1991) Plant Roots: The Hidden Half, pp. 309-330, Marcel Dekker, NY]. We show, in a model system consisting of excised tobacco roots, that both alpha-DL-difluoromethylornithine (an inhibitor of putrescine biosynthesis) and the rolA gene (from the root-inducing transferred DNA of Agrobacterium rhizogenes) stimulate overall root growth and cause a conversion in the pattern of root system formation, producing a dominant or 'tap' root. These morphological changes are correlated with a depression in the accumulation of polyamines and their conjugates.

Coumaric Acids↗