A Swedish model of prelicensure general practice residency.
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General Practice, Dental↗
Biomedical subjects
R Moore
Publications and source records attributed to R Moore.
Adrenal adenocarcinomas: histologic grading and survival.
Thirty-eight patients with adrenal adenocarcinoma were reviewed. Two of 23 males and 8 of 15 females had a functioning tumor (P less than 0.005). The most striking finding in this review was the variation in survival according to histologic grade. The median survival from histologic diagnosis was for grade I tumors 54 months, for grade II tumors 26 months, for grade III tumors 1 month. The difference in survival between patients with grade I or II tumors and those with grade III tumors was significant (P less than 0.001). The majority of the patients with grade III tumors were admitted with clinical evidence of disseminated disease and died within 1 month. Among the patients with well-differentiated tumors, five who received surgical treatment of their recurrence had a median survival of 51 months, whereas seven patients who received no surgical treatment had median survival of 20 months following first recurrence (0.05 less than P less than 0.10).
Adenocarcinoma↗
Nonviral infectious agents and marmoset (Saguinus oedipus) colitis.
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Animal Diseases↗
Characterization of spontaneous colitis in cotton-top tamarins (Saguinus oedipus) and its response to sulfasalazine.
Chronic colitis in the cotton-top tamarin (CTT) has been characterized by obtaining distal colonic biopsy specimens, hematocrits, serum albumins, and stools for bacteriologic and parasitic examination in nondebilitated living CTTs. The species specificity of the histologic features of colitis observed in the CTT was assessed by obtaining distal colonic biopsy specimens from 10 animals of other primate species for histologic examination. Histologic evidence of active colitis was found in 50% of adult CTTs but was absent in all non-CTT species studied. Forty-two stool samples obtained from 18 CTTs yielded only one isolate (Campylobacter). In addition to active colitis, CTT rectal mucosa also often had subtle irregularities in mucosal structure that were not present in nonrelated primate species and might represent chronic colitis. Metaplasia was not observed. The therapeutic effects of oral sulfasalazine (50 mg/kg X day) on CTT colitis were assessed in a randomized 10-wk placebo controlled crossover study. This study demonstrated significant improvement in disease activity as judged histologically (p less than 0.05) and significant increases in animal weight (p less than 0.01) and serum albumin (p less than 0.01) during sulfasalazine therapy when compared with saline control. Sulfasalazine therapy can ameliorate the effects of this disease and offers promise in maintaining experimental colonies of this endangered species for future studies.
Animals↗
Colonic mucin composition in primates. Selective alterations associated with spontaneous colitis in the cotton-top tamarin.
Heterogeneity of colonic mucin glycoprotein was examined in rectal mucosal biopsy specimens from a variety of primate species (Saguinus oedipus, n = 18; Macaca mulatta, n = 2; Macaca fascicularis, n = 2; Aotus trivirgatus, n = 2; Saimiri sciureus, n = 2; and Callithrix jacchus, n = 2). After initial separation of radiolabeled mucin and nonmucin glycoproteins solubilized from mucosal biopsy specimens, at least five labeled mucin components were found in monkey rectal mucosa in contrast to the six mucin fractions observed in the human colon. Although primates consistently lacked the earliest eluting component present in human colonic mucin, other mucin components cochromatographed with comparable fractions previously identified in human colonic biopsy specimens. The relative proportions of each fraction were consistent throughout all species except the cotton-top tamarin (S. oedipus), an animal that develops a chronic colitis. The cotton-top tamarin was found to have a markedly reduced amount of one mucin component (IV) in a manner analogous to the reduction in a human mucin fraction previously noted in patients with ulcerative colitis. Sequential evaluation of mucin profiles in cotton-top tamarins (n = 12) treated with sulfasalazine (50 mg/kg X day) or placebo in a 10-wk double-blind crossover study demonstrated the persistence of the selective reduction in tamarin species IV unrelated to disease activity. In contrast, the relative amount of tamarin mucin III was greater in association with increased disease activity than that observed in association with reduced disease activity (46% +/- 11% total mucin vs. 19% +/- 7% total mucin posttreatment).
Animals↗
The relationship between faecal endotoxin and faecal microflora of the C57BL mouse.
We studied the effect of oral selective antibiotic decontamination (SD) on the faecal endotoxin content and microflora in individual C57BL mice. Suppression of the coliform count was associated with an initial rise in faecal endotoxin concentration from 0.1 to 3.1 mg/g wet faeces during the first week of SD, which fell to 0.04 mg/g during the second week of treatment. Cessation of SD resulted in an immediate sharp increase in coliform count followed by its decline and gradual recovery to pre-treatment counts. Faecal endotoxin levels followed a parallel course. SD did not effect significantly the counts of lactobacilli, bacteroides and enterococci. It appears that the coliform population is responsible for the overall level of faecal endotoxin, and that during the initial period of SD endotoxin levels are elevated, an effect which may be mediated by antibiotic-enhanced release of endotoxin.
Amphotericin B↗
Growth and graviresponsiveness of primary roots of Zea mays seedlings deficient in abscisic acid and gibberellic acid.
The objective of this research was to determine if gibberellic acid (GA) and/or abscisic acid (ABA) are necessary for graviresponsiveness by primary roots of Zea mays. To accomplish this objective we measured the growth and graviresponsiveness of primary roots of seedlings in which the synthesis of ABA and GA was inhibited collectively and individually by genetic and chemical means. Roots of seedlings treated with Fluridone (an inhibitor of ABA biosynthesis) and Ancymidol (an inhibitor of GA biosynthesis) were characterized by slower growth rates but not significantly different gravicultures as compared to untreated controls. Gravicurvatures of primary roots of d-5 mutants (having undetectable levels of GA) and vp-9 mutants (having undectable levels of ABA) were not significantly different from those of wild-type seedlings. Roots of seedlings in which the biosynthesis of ABA and GA was collectively inhibited were characterized by gravicurvatures not significantly different for those of controls. These results (1) indicate that drastic reductions in the amount of ABA and GA in Z. mays seedlings do not significantly alter root graviresponsiveness, (2) suggest that neither ABA nor GA is necessary for root gravicurvature, and (3) indicate that root gravicurvature is not necessarily proportional to root elongation.
Abscisic Acid↗
A morphometric analysis of the redistribution of organelles in columella cells in primary roots of normal seedlings and agravitropic mutants of Hordeum vulgare.
The redistribution of organelles in columella cells of horizontally-oriented roots of Hordeum vulgare was quantified in order to determine what structural changes in graviperceptive (i.e., columella) cells are associated with the onset of the root gravicurvature. The sedimentation of amyloplasts is the only major change in cellular structure that correlates positively with the onset of root gravicurvature, which begins within 15 min after re-orientation. There is no consistent contact between sedimented amyloplasts and any other organelles. Nuclei are restricted to the proximal ends of columella cells in vertically-oriented roots, and remain there throughout gravicurvature after roots are oriented horizontally. Root gravicurvature does not involve significant changes in (1) the volume of columella cells, (2) the relative or absolute volumes of organelles in columella cells, or (3) the distribution of endoplasmic reticulum (ER). The size, number and sedimentation rates of amyloplasts in columella cells of non-graviresponsive roots of mutant seedlings are not significantly different from those of graviresponsive roots of normal seedlings. Similarly, there is no significant difference in (1) cellular volume, (2) distribution or surface area of ER, (3) patterns or rates of organelle redistribution in horizontally-oriented roots, (4) relative or absolute volumes of organelles in columella cells of graviresponsive and non-graviresponsive roots. These results suggest that the lack of graviresponsiveness by roots of mutant seedlings is probably not due to either (1) structural differences in columella cells, or (2) differences in patterns or rates of organelle redistribution as compared to that characteristic of graviresponsive roots. Thus, the basis of non-graviresponsiveness in this mutant is probably different from other agravitropic mutants so far studied.
Endoplasmic Reticulum↗
Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L.
The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.
Abscisic Acid↗
The involvement of glucose-6-phosphatase in mucilage secretion by root cap cells of Zea mays.
In order to determine the involvement of glucose-6-phosphatase in mucilage secretion by root cap cells, we have cytochemically localized the enzyme in columella and peripheral cells of root caps of Zea mays. Glucose-6-phosphatase is associated with the plasmalemma and cell wall of columella cells. As columella cells differentiate into peripheral cells and begin to produce and secrete mucilage, glucose-6-phosphatase staining intensifies and becomes associated with the mucilage and, to a lesser extent, the cell wall. Cells being sloughed from the cap are characterized by glucose-6-phosphatase staining being associated with the vacuole and plasmalemma. These changes in enzyme localization during cellular differentiation in root caps suggest that glucose-6-phosphatase is involved in the production and/or secretion of mucilage by peripheral cells of Z. mays.
Cell Differentiation↗
Changes in the distribution of plastids and endoplasmic reticulum during cellular differentiation in root caps of Zea mays.
In calyptrogen cells of Zea mays, proplastids are distributed randomly throughout the cell, and the endoplasmic reticulum (ER) is distributed parallel to the cell walls. The differentiation of calyptrogen cells into columella statocytes is characterized by the following sequential events: (1) formation of ER complexes at the distal and proximal ends of the cell, (2) differentiation of proplastids into amyloplasts, (3) sedimentation of amyloplasts onto the distal ER complex, (4) breakdown of the distal ER complex and sedimentation of amyloplasts to the bottom of the cell, and (5) formation of sheets of ER parallel to the longitudinal cell walls. Columella statocytes located in the centre of the cap each possess 4530 +/- 780 micrometers2 of ER surface area, an increase of 670 per cent over that of calyptrogen cells. The differentiation of peripheral cells correlates positively with (1) the ER becoming arranged in concentric sheets, (2) amyloplasts and ER becoming randomly distributed, and (3) a 280 per cent increase in ER surface area over that of columella statocytes. These results are discussed relative to graviperception and mucilage secretion, which are functions of columella and peripheral cells, respectively.
Cell Differentiation↗
Root graviresponsiveness and columella cell structure in carotenoid-deficient seedlings of Zea mays.
Root graviresponsiveness in normal and carotenoid-deficient mutant seedlings of Zea mays was not significantly different. Columella cells in roots of mutant seedlings were characterized by fewer, smaller, and a reduced relative volume of plastids as compared to columella cells of normal seedlings. Plastids in columella cells of mutant seedlings possessed reduced amounts of starch. Although approximately 10 per cent of the columella cells in mutant seedlings lacked starch, their plastids were located at the bottom of the cell. These results suggest that (i) carotenoids are not necessary for root gravitropism, (ii) graviresponsiveness is not necessarily proportional to the size, number, or relative volume of plastids in columella cells, and (iii) sedimentation of plastids in columella cells may not result directly from their increased density due to starch content. Plastids in columella cells of normal and mutant seedlings were associated with bands of microtubule-like structures, suggesting that these structures may be involved in 'positioning' plastids in the cell.
Carotenoids↗
Calcium movement, graviresponsiveness and the structure of columella cells and columella tissues in roots of Allium cepa L.
Roots of Allium cepa L. cv. Yellow are differentially responsive to gravity. Long (e.g. 40 mm) roots are strongly graviresponsive, while short (c.g. 4 mm) roots are minimally responsive to gravity. Although columella cells of graviresponsive roots are larger than those of nongraviresponsive roots, they partition their volumes to cellular organelles similarly. The movement of amyloplasts and nuclei in columella cells of horizontally-oriented roots correlates positively with the onset of gravicurvature. Furthermore, there is no significant difference in the rates of organellar redistribution when graviresponsive and nongraviresponsive roots are oriented horizontally. The more pronounced graviresponsiveness of longer roots correlates positively with (1) their caps being 9-6 times more voluminous, (2) their columella tissues being 42 times more voluminous, (3) their caps having 15 times more columella cells, and (4) their columella tissues having relative volumes 4.4 times larger than those of shorter, nongraviresponsive roots. Graviresponsive roots that are oriented horizontally are characterized by a strongly polar movement of 45Ca2+ across the root tip from the upper to the lower side, while similarly oriented nongraviresponsive roots exhibit only a minimal polar transport of 45Ca2+. These results indicate that the differential graviresponsiveness of roots of A. cepa is probably not due to either (1) ultrastructural differences in their columella cells, (2) differences in the rates of organellar redistribution when roots are oriented horizontally. Rather, these results indicate the graviresponsiveness may require an extensive columella tissue, which, in turn, may be necessary for polar movement of 45Ca2+ across the root tip.
Biological Transport↗
Geoperception in primary and lateral roots of Phaseolus vulgaris (Fabaceae). III. A model to explain the differential georesponsiveness of primary and lateral roots.
Half-tipped primary and lateral roots of Phaseolus vulgaris bend toward the side of the root on which the intact half tip remains. Therefore, tips of lateral and primary roots produce growth effectors capable of inducing gravicurvature. The asymmetrical placement of a tip of a lateral root onto a detipped primary root results in the root bending toward the side of the root onto which the tip was placed. That is, the lesser graviresponsiveness of lateral roots as compared with primary roots is not due to the inability of their caps to produce growth inhibitors. The more pronounced graviresponsiveness of primary roots is positively correlated with the presence of columella tissues that are 3.8 times longer, 1.7 times wider, and 10.5 times more voluminous than the columellas of lateral roots. We propose that the lack of graviresponsiveness exhibited by lateral roots is due to the fact that they (i) produce smaller amounts of the inhibitor than primary (i.e., strongly graviresponsive) roots and (ii) are unable to redistribute the inhibitor so as to be able to create a concentration gradient sufficient to induce a pronounced gravitropic response.
Fabaceae↗
Dentist unemployment--a Scandinavian reality.
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Adult↗
Dental education in Sweden: cultural perspective, structure, and issues.
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Culture↗
A morphometric analysis of cellular differentiation in caps of primary and lateral roots of Helianthus annuus.
In order to determine if patterns of cell differentiation are similar in primary and lateral roots, I performed a morphometric analysis of the ultrastructure of calyptrogen, columella, and peripheral cells in primary and lateral roots of Helianthus annuus. Each cell type is characterized by a unique ultrastructure, and the ultrastructural changes characteristic of cellular differentiation in root caps are organelle specific. No major structural differences exist in the structures of the composite cell types, or in patterns of cell differentiation in caps of primary vs. lateral roots.
Cell Differentiation↗
Movement of calcium across tips of primary and lateral roots of Phaseolus vulgaris.
Calcium (Ca) movement across tips of primary and lateral roots of Phaseolus vulgaris was determined by applying 45Ca2+ to one side of the root and collecting radioactivity in an agar receiver block on the opposite side of the root. The ratios of cpm in receiver blocks on the bottom of primary roots : cpm in receiver blocks on the top of the primary roots were 1.87 and 2.47 after 1 and 2 hr, respectively. This polar transport of Ca across tips of primary roots correlated positively with a graviculture of 43 degrees after 2 hr. The ratio of cpm in receiver blocks on the bottom of lateral roots : cpm in receiver blocks on the top of lateral roots was 1.20 after 2 hr. The decreased polar movement of Ca across tips of lateral roots correlated positively with lateral roots being nongraviresponsive. These data 1) support the suggestion that gravistimulation induces polar movement Ca toward the lower side of tips of primary roots, and 2) suggest that the reduced polar movement of Ca across tips of lateral roots may be involved in uncoupling gravistimulation from gravicurvature in lateral roots.
Biological Transport↗