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Biomedical subjects

R Moore

Publications and source records attributed to R Moore.

At least 361 records · Page 20Linked to original sources
PubMed1985

Graviresponsiveness and abscisic-acid content of roots of carotenoid-deficient mutants of Zea mays L.

The abscisic-acid (ABA) content of roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays was analyzed using gas chromatography-mass spectrometry with an analysis sensitivity of 6 ng ABA g-1 fresh weight (FW). Roots of normal seedlings of the same lines were characterized by the following amounts of ABA (as ng ABA g-1 FW, +/- standard deviation): w-3, 279 +/- 43; vp-5, 237 +/- 26; vp-7, 338 +/- 61. We did not detect any ABA in roots of any of the mutants. Thus, the lack of carotenoids in these mutants correlated positively with the apparent absence of ABA. Primary roots of normal and mutant seedlings were positively gravitropic, with no significant differences in the curvatures of roots of normal as compared with mutant seedlings. These results indicate that ABA 1) is synthesized in maize roots via the carotenoid pathway, and 2) is not necessary for positive gravitropism by primary roots of Z. mays.

Abscisic Acid↗
PubMed1985

Inhibition of gravitropism in primary roots of Zea mays by chloramphenicol.

Primary roots of Zea mays seedlings germinated and grown in 0.1 mM chloramphenicol (CMP) were significantly less graviresponsive than primary roots of seedlings germinated and grown in distilled water. Elongation rates of roots treated with CMP were significantly greater than those grown in distilled water. Caps of control and CMP-treated roots possessed extensive columella tissues comprised of cells containing numerous sedimented amyloplasts. These results indicate that the reduced graviresponsiveness of CMP-treated roots is not due to reduced rates of elongation, the absence of the presumed gravireceptors (i.e., amyloplasts in columella cells), or reduced amounts of columella tissue. These results are consistent with CMP altering the production and/or transport of effectors that mediate gravitropism.

Chloramphenicol↗
PubMed1985

Danish dental education: a cultural perspective.

The effects of Danish cultural traditions on dental education in Denmark are described, as well as the system's current structure and developing issues. Some Danish ideas for future exports of dental education programs and dental personnel are also discussed.

Curriculum↗
PubMed1984

Intestinal sclerosis with pseudo-obstruction in three dogs.

Intestinal sclerosis causing chronic intestinal pseudo-obstruction was diagnosed in 3 dogs. The pseudo-obstruction was characterized by vomiting and weight loss of 2 weeks' to 3 months' duration. A patent intestinal lumen was determined by contrast radiography and verified at surgery. Intestinal biopsy revealed diffuse atrophy, fibrosis, and mononuclear cell infiltration of the tunica muscularis. Each dog was euthanatized because of a progressive, deteriorating clinical course.

Animals↗
PubMed1984

Intramural intestinal hematoma causing obstruction in three dogs.

Intramural hematoma of the intestine caused intestinal obstruction in three dogs. Two dogs were examined because of vomiting and anorexia of several weeks' duration. In one of these, an intramural hematoma of the duodenum was associated with chronic pancreatitis. A cause was not found in the second dog. The third dog, which had clinical and radiographic evidence of gastric dilatation, was found at surgery to have hemoperitoneum associated with a ruptured intramural intestinal hematoma. In 1 dog, the hematoma was evacuated through a serosal incision. In the other 2 dogs, the problem was resolved by resection of the involved segment of intestine, followed by anastomosis. All 3 dogs recovered without complications.

Animals↗
PubMed1984

Malignant soft tissue tumors of nerve sheath origin.

Thirty-one patients with neurogenic sarcomas treated at Roswell Park Memorial Institute (RPMI) during a 10-year period were studied. The mean follow-up is 35.5 months. A specific nerve of origin could not be identified in 61.3% of patients. The most frequent site was the proximal lower extremity (38.7%). The only presenting symptom was enlarging mass in 67.7%. There was association with Von Recklinghausen's disease in 42% of the cases. Survival was significantly worse in tumors with Von Recklinghausen's disease (25.6%) compared to patients with solitary malignant schwannomas (50.9%). Twelve of 18 patients who had adequate surgical treatment initially remain disease-free, whereas only 2 of 11 patients referred following partial excision or recurrence remain disease-free (P less than 0.02). Eleven of 18 patients with grade I or II tumor are disease-free, whereas 2 of 10 patients with grade III tumor are disease-free (P less than 0.05). Resection of the sciatic nerve with wide excision is accompanied with a good functional result.

Adolescent↗
PubMed1984

Graviresponsiveness and the development of columella tissue in primary and lateral roots of Ricinus communis.

Half-tipped primary and lateral roots of Ricinus communis cv Hale bend toward the side of the root on which the intact half-tip remains. Therefore, the minimal graviresponsiveness of lateral roots is not due to the inability of their caps to produce growth effectors (presumably inhibitors). The columella tissues of primary (i.e. graviresponsive) roots are (a) 4.30 times longer, (b) 2.95 times wider, (c) 37.4 times more voluminous, and (d) composed of 17.2 times more cells than those of lateral roots. The onset of positive gravitropism by lateral roots is positively correlated with a (a) 2.99-fold increase in length, (b) 2.63-fold increase in width, (c) 20.7-fold increase in volume of their columella tissues. We propose that the minimal graviresponsiveness of lateral roots is due to the small size of their columella tissues, which results in their caps being unable to (a) establish a concentration gradient of the effector sufficient to induce gravicurvature and (b) produce as much as the effector as caps of graviresponsive roots.

Ricinus communis↗
PubMed1984

Geoperception in primary and lateral roots of Phaseolus vulgaris (Fabaceae). II. Intracellular distribution of organelles in columella cells.

A morphometric analysis of the ultrastructures of columella cells in primary and lateral roots of Phaseolus vulgaris was performed to determine the precise location of cellular components in these cells. Roots were fixed in situ to preserve the in vivo ultrastructure of the cells. All cellular components in columella cells of both types of roots were distributed asymmetrically. The nucleus and vacuome were located primarily in the middle third of both types of columella cells. Dictyosomes, mitochondria, and amyloplasts were most abundant in the lower third of the columella cells in both types of roots. The distribution of amyloplasts was the most asymmetrical of all cellular components examined, with the lower third of the columella cells containing approximately 90% of the relative volume of amyloplasts in both types of roots. The distribution of cellular components in columella cells of primary roots was not significantly different from that of columella cells of lateral roots. These results indicate that differences in georesponsiveness of primary and lateral roots of P. vulgaris are probably due to factors other than the ultrastructures of their individual columella cells.

Cytoplasm↗
PubMed1984

Graviresponsiveness and cap dimensions of primary and secondary roots of Ricinus communis (Euphorbiaceae).

After branching from the primary root, secondary roots of castor bean (Ricinus communis) grow laterally for 15-20 mm, after which they bend downward (i.e., become positively gravitropic). During the first 10 mm of growth, the lengths of caps of secondary roots increase from 120 +/- 26 to 220 +/- 28 micrometers. Although this increase is statistically significant (P < 0.1%), the resulting secondary roots are only minimally graviresponsive. A subsequent doubling of the lengths and widths of the root caps (i.e., to 420 +/- 34 and 450 +/- 41 micrometers, respectively) is positively correlated with the onset of gravicurvature. The graviresponsiveness and dimensions of caps of positively gravitropic secondary roots are not significantly different from those of positively gravitropic primary roots. These results indicate that (i) a statistically significant increase in the length and length : width ratio of a root cap does not necessarily result in the root becoming positively gravitropic, (ii) there may be a minimum cap length and (or) width necessary for graviresponsiveness, and (iii) the degree of graviresponsiveness exhibited by a particular root may be related to the size of its root cap.

Ricinus communis↗
PubMed1984

How roots perceive and respond to gravity.

During their growth and development, plants exhibit several types of tropisms and movements (e.g., epinasty, circumnutation, gravitropism, phototropism). The tropism first exhibited by most plants in the positive gravitropism characteristic of their newly emerged primary roots. Indeed, these roots must quickly "locate" water and minerals in the soil so as to insure survival of the plant. Thus, it is not surprising that the evolutionary process has produced an elegant system for graviperception and gravitropism by plant roots.

Gravitropism↗
PubMed1984

Growth, graviresponsiveness and abscisic-acid content of Zea mays seedlings treated with fluridone.

Ten-d-old seedlings of Zea mays L. cv. Tx 5855 treated with 1-methyl-3-phenyl-5-(3-[trifluoromethyl]phenyl)-4-(1H)-pyridinone (Fluridone) were analyzed for abscisic acid (ABA) content using high-performance liquid chromatography with an analysis sensitivity of 2.5 ng ABA g-1 fresh weight (FW). Seedlings were divided into three portions: leaves, detipped roots, and root tips (terminal 1.5 mm). Control plants (water treatment only; no Fluridone) were characterized by the following amounts of ABA: leaves, 0.114 +/- 0.024 (standard deviation) microgram ABA g-1 FW; detipped roots, 0.260 +/- 0.039 +/- microgram ABA g-1 FW; root tips, no ABA detected. We did not detect any ABA in tissues of Fluridone-treated plants. Primary roots of treated and untreated seedlings were strongly graviresponsive, with no significant differences between the curvatures or the growth rates of primary roots of Fluridone-treated and control seedlings. These results indicate that 1) Fluridone completely inhibits ABA synthesis, and 2) ABA is not necessary for positive gravitropism by primary roots of Zea mays.

Abscisic Acid↗
PubMed1984

Graviresponsiveness and columella cell structure in primary and secondary roots of Ricinus communis.

In order to determine what structural changes are associated with the onset of graviresponsiveness by plant roots, we have monitored the quantitative ultrastructures of columella (i.e., graviperceptive) cells in primary and secondary roots of Ricinus communis. The relative volumes of cellular components in lateral (i.e., minimally graviresponsive) roots were not significantly different from those of primary roots. The relative volumes of cellular components in secondary roots growing laterally were not significantly different from those of graviresponsive secondary roots. Therefore, the onset of graviresponsiveness by secondary roots of R. communis is not correlated with changes in organellar concentrations in columella cells. These results are discussed relative to a model for the differential graviresponsiveness of plant roots.

Ricinus communis↗