Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Nodule development”

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

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

At least 451 records · Page 25Linked to original sources
PubMed1993

Time-dependent modulation of liver lesion development in Opisthorchis-infected Syrian hamster by an antihelminthic drug, praziquantel.

In the North-east of Thailand, repeated antihelminthic therapy has been introduced for control of the opisthorchiasis known to be a major risk factor for cholangiocellular carcinomas. What influence this may have on tumorigenesis, however, remains unclear. The effects of administration of praziquantel, an antihelminthic drug, at different time points subsequent to infection with Opisthorchis viverrini (OV) on 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN)-initiated lesion development in the liver of female Syrian hamsters were therefore investigated. Praziquantel (250 mg/kg body weight, i.p.) was given 4, 12 or 20 weeks after infection of DHPN-treated animals (two 1000 mg/kg i.p. injections at weeks 0 and 2) with 60 OV metacercariae (at week 4). Survivors at week 38 were killed and examined. It was found that whereas praziquantel administration at the earlier two time points was effective at reducing hepatocellular nodule development, the results for cholangiocellular lesions were less pronounced, significant reduction only being evident in hamsters treated 4 weeks after parasite infestation. The findings thus indicate that enhancement of DHPN-initiated bile duct carcinogenesis by opisthorchiasis is both rapid and to a large degree irreversible. Hepatocellular lesion development in this model, on the other hand, appears to correlate more closely with the duration of parasite-associated proliferative stimulus.

Animals↗
PubMed1980

Thyroid nodules and thyroid cancer: surgical aspects.

Patients with thyroid nodules must be treated selectively because these nodules develop far more frequently than does thyroid cancer. A thorough clinical history, family history and history of radiation, as well as an accurate physical examination, are very important in determining whether surgical treatment is indicated. Thyroid function tests, a radioactive isotope scan, a thyroid echogram and fine-needle biopsy are also useful. Although there is considerable debate concerning the amount of thyroid tissue that should be removed at operation, the minimal procedure for a "cold," solid thyroid nodule is a total thyroid lobectomy and isthmectomy. This is the treatment of choice for patients with occult papillary thyroid carcinoma. Partial lobectomy is to be discouraged. Near total or total thyroidectomy should be considered for all other patients with differentiated thyroid cancer. Many factors influence the prognosis of patients with thyroid cancer including age, sex, type of thyroid cancer, invasion, symptoms, lymph node metastasis, metastasis to distant sites, extent of the surgical procedure, and use of radioactive iodine and thyroid hormone. With adequate treatment, the prognosis for differentiated thyroid carcinoma is excellent.

Adolescent↗
PubMed1995

Classification criteria for rheumatoid arthritis.

The development of classification schemes for RA in the last 40 years has followed the increasingly precise understanding of the nature of the clinical disease and the recognition of the different requirements of classification methods in clinic and population settings. In published studies of RA in clinic patients the most widely used criteria sets have been the 1958 ARA (ACR) criteria and its 1961 adaptation (the Rome (active) criteria). These sets classified disease as 'classical', 'definite', 'probable' and 'possible' RA based on criteria comprising clinical, serological, radiological and histological features (the latter were dropped from the Rome criteria set because of their impracticality). More recently, a new criteria set (the 1987 ARA criteria) has been developed using statistical techniques. This set was derived using RA cases and controls attending hospital clinics. It is based on the earlier criteria sets but accommodates the characteristic pattern of joint involvement in RA more precisely. The criteria recognize only the single disease category of 'rheumatoid arthritis'. In validation studies, the 1987 criteria set has been found to have enhanced specificity over earlier schemes in clinic-based studies of RA. The sensitivity may, however, be reduced, in particular in studies of early disease. The application of classification criteria for case recognition in the population and family studies of RA has proved more problematic. In these settings, there is the additional requirement to recognize individuals with remitted and inactive disease as RA cases. The 1966 New York criteria were developed for this specific purpose, however their format proved cumbersome and they have not been widely adopted. The 1987 criteria set is insufficiently sensitive to recognize inactive disease if the criteria are applied exactly as they have been defined. The sensitivity of the 1987 criteria set is, however, substantially enhanced if the criteria are adapted to incorporate features of past disease activity, for example by allowing deformity to substitute for swelling and by incorporating data on the past occurrence of rheumatoid factor and rheumatoid nodules. Developments in the immunology and genetics of RA may in the future provide more accurate tools for classification and may lead to recognition of more precise disease subsets. At present, however, the 1987 ARA criteria provide the most appropriate basis for case recognition in both clinic and population-based studies.

Arthritis, Rheumatoid↗
PubMed1992

Isolation and characterization of an ndvB locus from Rhizobium fredii.

A gene (ndvB) in Rhizobium meliloti that is essential for nodule development in Medicago sativa (alfalfa), specifies synthesis of a large membrane protein. This protein appears to be an intermediate in beta-1,2-glucan synthesis by the microsymbiont. Southern hybridization analysis showed strong homology between an ndvB (chvB) probe and genomic DNA of R. fredii but not from Bradyrhizobium japonicum. A cosmid clone containing the putative ndvB locus was isolated from a Rhizobium fredii gene library. The cosmid clone which complemented R. meliloti ndvB mutants for synthesis of beta-1,2-glucans and effective nodulation of alfalfa was mapped and subcloned. Fragment-specific Tn5 mutagenesis followed by homologous recombination into the R. fredii genome indicated that the region was essential for beta-1,2-glucan synthesis and for formation of an effective symbiosis with Glycine max (soybean).

DNA, Bacterial↗
PubMed1988

Symbiotic loci of Rhizobium meliloti identified by random TnphoA mutagenesis.

We have developed a system for using TnphoA (TnphoA is Tn5 IS50L::phoA), which generates fusions to alkaline phosphatase (C. Manoil and J. Beckwith, Proc. Natl. Acad. Sci. USA 82:8129-8133, 1985), in Rhizobium meliloti. Active fusions expressing alkaline phosphatase can arise only when this transposon inserts in genes encoding secreted or membrane-spanning proteins. By confining our screening to 1,250 TnphoA-generated mutants of R. meliloti that expressed alkaline phosphatase, we efficiently identified 25 symbiotically defective mutants, all of which formed ineffective (Fix-) nodules on alfalfa. Thirteen of the mutants were unable to synthesize an acidic exopolysaccharide (exo::TnphoA) that is required for nodule invasion. Twelve of the mutations created blocked at later stages of nodule development (fix::TnphoA) and were assigned to nine symbiotic loci. One of these appeared to be a previously undescribed locus located on the pRmeSU47a megaplasmid and to encode a membrane protein. Two others were located on the pRmeSU47b megaplasmid: one was a new locus which was induced by luteolin and encoded a membrane protein, and the other was dctA, the structural gene for dicarboxylic acid transport. The remaining six loci were located on the R. meliloti chromosome. One of these was inducible by luteolin and encoded a membrane protein which determined lipopolysaccharide structure. Three additional chromosomal loci also appeared to encode membrane proteins necessary for symbiosis. The remaining two chromosomal loci encoded periplasmic proteins required for symbiosis.

Alkaline Phosphatase↗
PubMed1981

Cell types involved in the expression of foetal aldolases during rat azo-dye hepatocarcinogenesis.

Cellular and subcellular immunolocalization of aldose isozymes and alpha-foetoprotein (AFP) was performed in rat liver during the different stages of carcinogenesis induced by 3'-methyl-4-dimethylaminoazobenzene. During the early stages, double-labelling experiments showed that oval and transitional cells that expressed foetal aldolases did not contain adult aldolase B; this isozyme was only found in small and "normal' hepatocytes. AFP was present in transitional cells and in small hepatocytes. During hyperplastic nodule development, neither foetal aldolases nor AFP were located in hepatocytes. These foetal proteins were still observed in transitional cells. In hepatocellular carcinomas, both foetal proteins (aldolase isozymes and AFP) and adult aldolase B were present in malignant cells. Moreover, during the different stages foetal aldolases were also found in sinusoidal cells. These results indicate that, during azo-dye hepatocarcinogenesis, (a) several cell types synthesize foetal aldolases: oval and transitional cells, hepatoma cells and sinusoidal cells; (b) only hepatoma cells and not hepatocytes located in hyperplastic nodules can express both foetal and adult aldolases. This suggests that in primary, as in transplanted, hepatoma the resurgence of foetal isozymes is the consequence of a disturbance of control gene expression.

Animals↗
PubMed1993

Chromatin changes in cell transformation: progressive unfolding of the higher-order structure during the evolution of rat hepatocyte nodules. A differential scanning calorimetry study.

Using differential scanning calorimetry and complementary ultrastructural observations, we have characterized the status of chromatin during the transformation of rat hepatocytes in the resistant hepatocyte model of Solt and Farber (1976. Nature (Lond.). 263:701-703). Differential scanning calorimetry affords a measure of the degree of condensation of chromatin in situ and has therefore been used in this work for the purpose of establishing the nature of the structural changes associated with the emergence of successive cellular populations. Since the resistant hepatocyte model generates a series of synchronous phenotypic changes, it was possible to determine unambiguously the content of heterochromatin at each step of the process. The higher-order structure undergoes a partial relaxation in early developing nodules, isolated 16 weeks after initiation; the thermal transition at 90 degrees C, which is characteristic of noninteracting core particles, increases with respect to control hepatocytes. Dramatic changes occur in persistent (46-week) nodules. The 90 degrees C endotherm dominates the thermogram, while the transition at 107 degrees C, corresponding to the denaturation of the core particle packaged within the heterochromatic domains, disappears. The complete loss of the higher-order structure at this stage of transformation has been further verified by ultrastructural observations on thin nuclear sections. Ten-nm filaments, having a beaded appearance, are scattered throughout the nucleoplasm and clearly result from the decondensation of 30-nm-thick fibers. This catastrophic relaxation process cannot be related to an effective increase in gene activity. Rather, our observations suggest that during transformation chromatin is in a state of high transcriptional competence associated with the alert of general cellular programs. This view is consistent with the finding that in persistent nodules the DNA is extensively hypomethylated with respect to normal liver.

Animals↗
PubMed1997

Expression of early nodulin genes in alfalfa mycorrhizae indicates that signal transduction pathways used in forming arbuscular mycorrhizae and Rhizobium-induced nodules may be conserved.

Transcripts for two genes expressed early in alfalfa nodule development (MsENOD40 and MsENOD2) are found in mycorrhizal roots, but not in noncolonized roots or in roots infected with the fungal pathogen Rhizoctonia solani. These same two early nodulin genes are expressed in uninoculated roots upon application of the cytokinin 6-benzylaminopurine. Correlated with the expression of the two early nodulin genes, we found that mycorrhizal roots contain higher levels of trans-zeatin riboside than nonmycorrhizal roots. These data suggest that there may be conservation of signal transduction pathways between the two symbioses-nitrogen-fixing nodules and phosphate-acquiring mycorrhizae.

Journal Article↗
PubMed2004

[Malignant pleural mesothelioma: radiotherapy for the prevention of seeding nodules].

INTRODUCTION: Radiotherapy for the prevention of skin nodules appearing at the sites of aspiration, needle biopsies, chest drains or surgical incisions is the only treatment currently recommended for malignant mesothelioma. METHODS: 59 patients suffering from this condition were identified from the database of the Nantes Regional Cancer Centre. 33 received prophylactic irradiation, 25 did not and 1 was excluded. RESULTS: The treated group showed typical demographic and histological features. The delay in initiating radiotherapy ranged from 10 to 123 days and several different treatment regimes were used. In the treated group 7 out of 32 patients developed nodules following radiotherapy with 4 recurrences in the treated and 3 in the untreated areas. The mean interval before recurrence was 9 months (range 3 to 17 months). The recurrence rate was lower in the treated (21%) than in the untreated group (48%;12 out of 25). CONCLUSIONS: The poor results compared with the reference series may be explained by a longer follow-up (mean 12 months), less thorough treatment of all puncture sites and a very long delay before treatment (mean 37 days).

Aged↗
PubMed1981

Differences in Endogenous Levels of Gibberellin-Like Substances in Nodules of Phaseolus lunatus L. Plants Inoculated with Two Rhizobium Strains.

Lima bean plants (Phaseolus lunatus L.) inoculated with Rhizobium sp. strain 127E14, which lacks constitutive nitrate reductase activity, were significantly taller after 4 weeks of age than plants inoculated with strain 127E15, which contains constitutive nitrate reductase activity. Plants inoculated with either strain responded to application of 5 micrograms gibberellic acid per plant with rapid internode elongation; plants inoculated with strain 127E15 became less responsive to gibberellic acid from 3 to 5 weeks of age, while plants inoculated with strain 127E14 did not. The height of plants inoculated with strain 127E14 was reduced by 20% with application of gibberellin biosynthesis inhibitors to the roots, while height of plants inoculated with strain 127E15 was unaffected.Plants inoculated with strain 127E14 developed nodules containing 4 to 50 times greater quantities of extractable gibberellin-like substances than the nodules of plants inoculated with strain 127E15. Plants inoculated with strain 127E14 had nodules containing larger quantities of gibberellin-like substances in both the acidic and basic ethyl acetate fractions, and these differences were observed before the onset of rapid growth responsible for the difference in plant height.The internode elongation in plants infected with strain 127E14, its reversal by gibberellin biosynthesis inhibitors, and the accumulation of large quantities of gibberellin-like substances in nodules infected with strain 127E14 support the hypothesis that root nodules may contribute gibberellins to the host.

Journal Article↗
PubMed1997

Cytologic findings in thyroid nodules after 131I treatment of hyperthyroidism.

Findings in seven cytologic specimens obtained with fine-needle aspiration biopsy were described in three patients in whom thyroid nodules developed after iodine 131 treatment of hyperthyroidism. In two patients, the presence of large bizarre cells with hyperchromatic nuclei, coarse chromatin, and prominent nucleoli suggested the possibility of malignancy, and in particular, anaplastic carcinoma. These bizarre nuclear changes were diffuse in one patient and focal in the other. In the third patient, nuclei with chromatin clearing, grooves, and nuclear pseudoinclusions suggested papillary carcinoma. At follow-up, lesions were benign in all three patients. We conclude that nuclear changes suggestive of either anaplastic carcinoma or papillary carcinoma may be seen in thyroid nodules after 131I treatment. Clues to the benign nature of these nodules include architectural arrangement of cells in cohesive clusters and flat sheets; presence of lymphocytes, histiocytes, colloid, cytoplasmic vacuoles, and Hürthle cells; and a clinical history of treatment with radioactive iodine.

Adult↗
PubMed1999

[Neonatal monoblastic leukemia revealed by transitory specific skin lesions].

BACKGROUND: Specific cutaneous involvement is frequently observed in congenital leukemia and may be the inaugural sign. Lesions may be non-specific and even regress spontaneously, misleading diagnosis and delaying care. CASE REPORT: A infant in good health had diffuse ecchymotic maculae at birth which totally regressed within 10 days. On day 20, a macular rash and three violet nodules developed. The physical examination found enlarged nodes, liver enlargement and poor general status. Blood cell counts and the myelogram led to the diagnosis of type 5 acute myeloblastic leukemia (AML 5). Search for extension revealed cutaneous leukemia and meningeal and renal involvement. DISCUSSION: The predominance of myelocyte forms is specific for neonatal leukemia (AML 5 and 4). Specific skin lesions are frequent (25 to 30 p. 100 of cases) and sometimes precede (7 p. 100) anomalies in peripheral and medullary smears. Skin biopsy with direct smear can provide rapid diagnosis. Classically subcutaneous nodules or bluish macropapulae give the blueberry muffin baby aspect. The polymorphous features and the remarkably fluctuating skin lesions in our case are unusual, especially since the infant did not have spontaneously reversible neonatal leukemia, a rare unpredictable phenomenon described in newborns with a normal phenotype which can mislead therapeutic management.

Age Factors↗
PubMed1977

Novel bacterium infecting an African snail.

Nodules found in the superficial tissues of laboratory-maintained snails (Bulinus jousseaumei) contained a bacterium of two forms. This nonmotile microorganism occurred in intracellular packets as a simple gram-negative rod that appeared to undergo intrapacket transition to a cephalotrichous form. The latter is characterized by a "head" from which emerge long, thick, rigid, flagella-like, helically constituted filamentous organelles with a core and an outer component that is not an extension of the bacterial envelope. Neither form was successfully cultured, but clean snails derived from eggs removed before hatching developed nodules within 1 to 3 months of exposure to infected snails. The infectivity was specific for the host snail, and no transmission occurred to snails of 5 other genera tested. The presence of nodules did not interfere with longevity or reproduction of infected snails. Details of infectivity, transition, and taxonomic position of the bacterium remain to be explored, but it is reported because of unique morphological and ultrastructural features not previously known.

Africa↗
PubMed1990

Expression of glutamine synthetase genes in roots and nodules of Phaseolus vulgaris following changes in the ammonium supply and infection with various Rhizobium mutants.

In this paper we have examined whether the four glutamine synthetase (gln) genes, expressed in roots and nodules of Phaseolus vulgaris are substrate-inducible by ammonium. Manipulation of the ammonium pool in roots, through addition and removal of exogenous ammonium, did not elicit any changes in the abundances of the four mRNAs thus suggesting that the gln genes in roots of this legume are neither substrate-inducible by ammonium nor derepressed during nitrogen starvation. In nodules the effect of the ammonium supply on expression of the gln genes has been examined by growing nodules under argon/oxygen atmospheres, or with a number of Fix- Rhizobium mutants, and following addition of exogenous ammonium. The results of these experiments suggest that the expression of the gln-gamma gene, which is strongly induced during nodule development, is primarily under a developmental control. However nitrogen fixation appears to have a quantitative effect on expression of gln-gamma as the abundance of this mRNA is about 2 to 4-fold higher under nitrogen-fixing conditions. This effect could not be mimicked by addition of exogenous ammonium and moreover is not specific to the gln-gamma gene as mRNA from a leghaemoglobin gene was similarly affected. Taken together these results have failed to find an effect of ammonium on specifically inducing the expression of glutamine synthetase genes in roots and nodules of P. vulgaris.

Ammonia↗
PubMed1991

Acute non-immunological inflammation inhibits natural killer (NK) activity in the lungs and enhances metastatic development.

A non-immunological acute inflammatory reaction, induced in rats by intrapleural injection of calcium pyrophosphate microcrystals, decreased natural killer activity of lung intracapillary leucocytes (LICL), and, to a lesser extent, of spleen cells. NK activity was significantly depressed as early as 2 h after pleurisy induction, maximally suppressed at 72 h (when the inflammation had resolved) and returned to near-normal values by day 10. This decrease in NK activity was demonstrated using YAC-I lymphoma cells and syngeneic fibrohistiocytoma (P77) cells, as targets. The inhibition of NK activity of LICL was accompanied by an impaired destruction of P77 tumour cells injected i.v. 3 days after the onset of pleurisy. This was shown by an increase in the number of radiolabelled tumour cells surviving in the lungs at 24 h and of tumour nodules developed in lung parenchyma at 3 weeks. Suppression of NK activity was not due to a decrease in the proportion of large granular lymphocytes (LGL) in the LICL population. Suppressor macrophages may be involved, at least in part, since a partial restoration of LICL cytotoxicity was obtained after depletion of plastic-adherent cells. The effect of inflammation was reproduced in normal rats by injecting inflammatory serum or PGE2, suggesting a possible role of circulating mediators.

Animals↗
PubMedDate not supplied

Natural progression of Oesophagostomum bifurcum pathology and infection in a rural community of northern Ghana.

An estimated 250,000 people in northern Ghana and Togo are infected with the intestinal helminth parasite Oesophagostomum bifurcum, as detected by stool cultures. Clinical disease caused by O. bifurcum is responsible for about 50 cases per year at the region's central hospital, and presents as painful abdominal masses: inflammatory colonic nodules containing live juvenile stages of the helminth. In individuals living in villages highly endemic with O. bifurcum infection, colonic pathology visible by ultrasound is also highly prevalent. These nodules also contain O. bifurcum juvenile worms but are apparently asymptomatic. Thus, O. bifurcum infection and asymptomatic colonic pathology are highly prevalent within this area, but clinical disease is relatively uncommon. The natural evolution and regression of the colonic pathology in an endemic community in northern Ghana and its distribution within the population is described. Of the 299 individuals in the study group, 28% had colonic pathology at recruitment in the late-rainy season, which decreased with a half-life of 3-4 months during the dry season. Of those negative at recruitment, 28% developed nodules during the year, the majority appearing at the end of the subsequent rainy season. Children tended to have a higher prevalence and intensity of ultrasound-visible pathology compared to adults. Almost half (49%) of the study group had colonic nodules at least once during the year, and 2% of these individuals presented with clinical disease to the local hospital during the mid-rainy season.

Adolescent↗
PubMed1966

Electron microscopy of the infection and subsequent development of soybean nodule cells.

Goodchild, D. J. (Commonwealth Scientific and Industrial Research Organization, Canberra, Australia), and F. J. Bergersen. Electron microscopy of the infection and subsequent development of soybean nodule cells. J. Bacteriol. 92:204-213. 1966-Electron microscopy of thin sections of the developing central tissue cells of young soybean root nodules has shown that infection is initiated by a few infection threads which penetrate cells of the young central tissue. Extension growth of the threads may be a result of pressure developed from the growth of the bacteria within the threads. Release of bacteria from a thread is preceded by the development on an infection thread of a bulge with a cellulose-free membrane-bounded extension; bacteria move from this into the host cells by an endocytotic process and remain enclosed in an infection vacuole which is bounded by a membrane of host-cell origin. Multiplication of the intracellular bacteria takes place within these vacuoles. Until the host cell becomes filled with bacteria, the vacuoles separate into discrete units at each division. Later, division of the bacteria occurs within each vacuole, thus leading to the mature structure of the central tissue cells in which several bacteria are enclosed within each membrane-bounded unit.

Bacteria↗
PubMed1996

Beta-glucan synthesis in Bradyrhizobium japonicum: characterization of a new locus (ndvC) influencing beta-(1-->6) linkages.

Bradyrhizobium japonicum synthesizes periplasmic cyclic beta-(1-->3),beta-(1-->6)-D-glucans during growth in hypoosmotic environments, and evidence is growing that these molecules may have a specific function during plant-microbe interactions in addition to osmoregulation. Site-directed Tn5 mutagenesis of the DNA region upstream of ndvB resulted in identification of a new gene (ndvC) involved in beta-(1--> 3), beta-(1-->6)-glucan synthesis and in nodule development. The predicted translation product was a polypeptide (ca. 62 kDa) with several transmembrane domains. It contained a sequence characteristic of a conserved nucleoside-sugar-binding motif found in many bacterial enzymes and had 51% similarity with a beta-glucanosyltransferase from Candida albicans. B. japonicum carrying a Tn5 insertion in ndvC resulted in synthesis of altered cyclic beta-glucans composed almost entirely of beta-(1--> 3)-glycosyl linkages. The mutant strain was only slightly sensitive to hypoosmotic growth conditions compared with the ndvB mutant, but it was severely impaired in symbiotic interactions with soybean (Glycine max). Nodulation was delayed by 8 to 10 days, and many small nodule-like structures apparently devoid of viable bacteria were formed. This finding suggests that the structure of the beta-glucan molecule is important for a successful symbiotic interaction, and beta-glucans may have a specific function in addition to their role in hypoosmotic adaptation.

Amino Acid Sequence↗