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PubMed1994

Polyclonal and monoclonal thyroid nodules coexist within human multinodular goiters.

Although somatic mutations have been identified in a subset of thyroid nodules, the pathogenesis of nodules in multinodular goiters remains unclear. Clonal analysis indicates whether a nodule arises from the polyclonal proliferation of a group of cells or forms a clone from a genetically altered cell. Individual thyroid nodules have been shown to be of polyclonal or monoclonal origin. In this study we examined the clonality of several different nodules in patients with multinodular goiters. Clonality was established using the X-chromosomal probe M27 beta, which detects a multiallelic polymorphism at the locus DXS255 in 90% of females. Twenty-five nodules from 9 multinodular goiters were analyzed; 9 nodules were polyclonal, and 16 were monoclonal. Three goiters contained only polyclonal nodules, whereas 3 contained only monoclonal nodules. Polyclonal and monoclonal nodules coexisted in 3 goiters. In 2 goiters, the monoclonal nodules were shown to derive from different progenitor cells. We conclude that polyclonal and monoclonal nodules may coexist in multinodular goiters and that monoclonal nodules can originate from different cells. The coexistence of polyclonal and monoclonal nodules suggests that different pathogenic mechanisms occur simultaneously or that monoclonal nodules emerge secondarily from a polyclonal population due to a growth advantage from a genetically altered cell.

Adult↗

PubMed2005

Transthoracic endosonography for the intraoperative localization of lung nodules.

BACKGROUND: Transthoracic ultrasonography has been advocated for the localization of lung nodules during video-assisted thoracoscopic surgery (VATS) for nonperipheral nodules. METHODS: Video-assisted thoracoscopic surgery for lung nodules was performed in 54 consecutive patients. Preoperative computed tomography (CT) diagnosed 65 lesions. Positron emission tomography (PET) identified 2 lesions not revealed by CT. All nodules were judged whether visible and/or palpable. Diameter and distance of the nodule from the anterior, lateral, and posterior chest wall were measured on CT scan and served in a discriminant analysis to predict which nodule would be neither visible nor palpable. The deflectable multifrequency (7.5 to 10 MHz) endosonography probe was used to identify the nonvisible and nonpalpable nodules. RESULTS: Resected nodules were 69; 67 diagnosed preoperatively, and 2 intraoperatively by ultrasonography. At VATS exploration 16 of 65 (25%) of the CT diagnosed nodules were nonvisible and nonpalpable. The discriminant analysis failed to predict correctly whether nodules would be visible and/or palpable in 33% because of surrounding severe emphysema, proximity to a fissure, or to the hylum. The endosonography identified 15 out of 16 of the nonvisible and nonpalpable nodules, thus conversion to thoracotomy was necessary for one nodule. The combination of video, palpatory, and endosonographic inspections had 98% sensitivity and 100% specificity in localizing the nodules. CONCLUSIONS: Intraoperative transthoracic ultrasonography is useful to guide VATS resection of lung nodules. It is a bedside tool, not requiring planning and coordination with the interventional radiology suite, thus you use it if you need it. It has no related morbidity, and may also have a role in revealing lesions occult at preoperative work-up.

Carcinoma, Non-Small-Cell Lung↗

PubMed2002

Long-term follow-up of thyroid nodule growth.

Benign thyroid nodules are common in iodine deficient countries. Although many recent studies have addressed the molecular basis and short-term outcome of treatment in nodular thyroid disease, data on the long-term follow-up of thyroid nodule growth are widely lacking. The aim of the present study was to evaluate the long-term behaviour of benign thyroid nodules growth. We followed 109 consecutive patients seen at yearly intervals in our Outpatient Clinic for at least 3 years (range 3-12 years, mean 4.9 +/- 2.6 years) presenting with 139 benign nodules in uni- or multinodular goiters. The size of the nodules and thyroid glands was analysed retrospectively. The study included a spectrum of benign thyroid nodules, 86 functioning and 53 non-functioning. 27 patients were treated with levothyroxine, 8 with iodide and 16 with a combination of both. 58 patients were not treated mainly because of thyroid functional autonomy. Patients with overt hyperthyroidism or suspected malignancy by fine-needle aspiration were excluded from the study. The nodules and glands were assessed by ultrasonography at yearly intervals and documented by photoprints. Relevant growth was defined as an increase in nodule volume of at least 30%. For statistical analyses, Cox Proportional Hazard Model and life-table analyses according to Kaplan-Meier were performed. Most thyroid nodules grew slowly but continuously during follow-up. After about 3 years, half of the nodules had increased their volume by at least 30%. Growth of the nodules was significantly faster than of the corresponding thyroid glands (p < 0.0001). Age and sex of the patients and size or function of the nodules at initial presentation were not significantly related to their growth. Suppression of TSH did not affect growth of the nodules irrespective of the source of thyroid hormones, endogenous or by administration of levothyroxine. In conclusion, benign thyroid nodules have a slow intrinsic growth potential, which is apparently higher than that of the non-nodular tissue. In this study, not only nodular but even non-nodular goiter growth continues in the majority of patients. Exogeneous factors, including therapy with levothyroxine and/or iodide, appear to have little effect on the growth behaviour.

Adolescent↗

PubMed2005

Interobserver variation for ultrasound determination of thyroid nodule volumes.

Thyroid ultrasound is used in the routine clinical assessment and the follow-up of thyroid disorders. The follow- up of patients with thyroid nodules is mostly based on thyroid nodule volume determinations performed by different observers. However, for the judgment of treatment effects there is uncertainty about the interobserver variation of thyroid nodule volume measurements by ultrasound because there are no prospective blinded studies available comparing the interobserver variation in thyroid nodule volume measurement. The aim of our study was therefore to determine the variation of thyroid nodule volume determinations for different observers. We conducted a prospective blinded trial. Our study population consisted of 42 probands (8 men, 34 women) with an uniform distribution of thyroid nodule sizes (25 uninodular and 17 multinodular thyroid glands). We compared the results of 3 ultrasonographers with certified experience in thyroid ultrasound. The interobserver variation for the determination of thyroid nodule volume (n = 38) was 48.96% for the ellipsoid method and 48.64% for the planimetric method. The interobserver variation for determining thyroid volume (n = 40) was 23.69% for the ellipsoid method and 17.82% for the planimetric method. A regression analysis revealed that the probability for the identification of the same nodule in nodular thyroids by all sonographers is 90%, if the nodule is at least 15mm in greatest diameter. Future investigations should not describe changes in nodule volume less than 50% as therapy effects because only volume changes of at least 49% or more can be interpreted as nodule shrinkage or growth. Reporting of nodule volume modification 50% or more and lack of information for ultrasound procedures introduce a bias in studies evaluating the effects of nodule treatments. The clinical interpretation of a shrinking/growing thyroid nodule based on volume determinations by ultrasound is not well established because it is difficult to reproduce a two-dimensional image plane for follow-up studies.

Adult↗

PubMed2002

Large-needle aspiration biopsy for the preoperative selection of follicular adenoma diagnosed by fine-needle aspiration as a microfollicular nodule or suspected cancer.

The preoperative fine-needle aspiration (FNA) cytologic diagnoses of microfollicular nodule and suspected cancer include nodules that yield histologic results of typically benign lesions, nodular hyperplasia and follicular adenomas, and differentiated thyroid cancer postoperatively. We reviewed the clinical and pathologic data for patients with palpable thyroid nodules with these two cytologic diagnoses; nodules were also examined by large-needle aspiration biopsy (LNAB) to assess whether the distinction achieved by LNAB in pure microfollicular or mixed microfollicular-macrofollicular nodules could be used preoperatively to better predict the diagnosis of follicular adenoma. One hundred fourteen nodules of this type were excised. Postoperative results were grouped in nodular hyperplasia (90 nodules), follicular adenoma (8), and differentiated carcinoma (16). The prevalence of the follicular adenoma and thyroid carcinoma postoperative findings was 33% among the microfollicular nodules and 5.9% among the microfollicular-macrofollicular nodules at preoperative LNAB, (p = 0.0004). Within the postoperatively benign nodules, the prevalence of follicular adenoma was 14.3% among the microfollicular nodules and 2% among the microfollicular-macrofollicular nodules at LNAB (p = 0.028). These data indicate that histologic examination of the LNAB specimen can be used to identify those thyroid nodules diagnosed by FNA as microfollicular nodules or suspected cancer, which are most likely to be follicular adenomas postoperatively.

Adenoma↗

PubMed2006

Accuracy of the CT numbers of simulated lung nodules imaged with multi-detector CT scanners.

A study was performed to determine the accuracies and reproducibilities of the CT numbers of simulated lung nodules imaged with multi-detector CT scanners. The nodules were simulated by spherical balls of three diameters (4.8, 9.5, and 16 mm) and two compositions (50 and 100 mg/cc CaCO3 in water-equivalent plastic). All were scanned in a liquid-water-filled container at the center of a water-equivalent-plastic phantom and in air cavities within the same phantom using GE multi-detector CT scanners. The nodules were also scanned within simulated lung regions in an anthropomorphic thorax section phantom that was bolused on both sides with water-equivalent slabs. Results were compared for three scanning protocols--the protocol for the National Lung Screening Trial (NLST), the protocol for the Lung Tissue Research Consortium (LTRC) study, and a high resolution (small pitch, thin slice and small scan interval) higher dose "gold standard" protocol. Scans were repeated three times with each protocol to assess reproducibility. The CT numbers of the nodules in water were found to be nearly independent of nodule size. However, the presence and the size of an air cavity surrounding a nodule had a significant effect (e.g., the CT number of a 50 mg/cc nodule was 64 HU in water, 37 HU in a 1.8 cm diameter air cavity, and 19 HU in a 4.4 cm diameter air cavity). This variability of CT number with size of air cavity may affect the results of the LTRC study in which patients are scanned at both full inspiration and full expiration. The CT numbers of the 9.5 and 16 mm diameter nodules within the anthropomorphic phantom were highly reproducible (average standard deviations of 2 HU or less) for all protocols. On the other hand, both accuracy and reproducibility were significantly degraded for the 4.8 mm diameter nodules, especially for the NLST (2.5 mm thickness, 2 mm slice interval) technique. Use of thinner slice (1.25 mm) and slice interval (1.25 mm) scans that can be reconstructed retrospectively from the multi-detector helical CT projection data of the standard NLST protocol yield CT numbers for the 4.8 mm diameter nodules that are more accurate and reproducible than those of the standard NLST technique. In general, the CT numbers of the nodules were found to be lower at positions near the centers of the lungs and near the spine, which is probably due to increased beam hardening in those regions. Also, larger nodules were found to have higher CT numbers than smaller nodules, consistent with results obtained on early single slice GE CT scanners. Until manufacturers develop quantitative CT scanners with improved x-ray beam hardening and scatter corrections, it is recommended that reference phantoms be employed to more accurately assess the calcium contents of patient lung nodules in screening and tissue characterization studies and in eventual computer-aided detection and diagnosis applications.

Algorithms↗

PubMed1999

Pulmonary nodules resected at video-assisted thoracoscopic surgery: etiology in 426 patients.

PURPOSE: To determine the etiology of pulmonary nodules resected at video-assisted thoracoscopic surgery (VATS) and establish the probabilities that single or multiple nodules resected at VATS represent malignancy in patients with or patients without known cancer. MATERIALS AND METHODS: Pathology reports from VATS performed between January 1995 and July 1997 were searched for data on gross specimens revealing pulmonary nodules 3 cm or smaller. Findings were correlated with clinical and histologic data. RESULTS: In 254 patients with one nodule resected at VATS, the nodules were malignant in 108 patients with and in 32 patients without known cancer (P < .03). Among 172 patients with multiple nodules resected, at least one nodule was malignant in 85 patients with and in 20 patients without known cancer (P > .05). Nodules larger than 1 cm were more likely to be malignant than were smaller nodules (P < .002). In patients with known malignancy, nodules smaller than 0.5 cm were more likely to be benign, whereas nodules larger than 0.5 cm but smaller than 1 cm were more likely to be malignant (P < .001). CONCLUSION: A single pulmonary nodule resected at VATS was more likely to be malignant in patients with known cancer. Nodules larger than 1 cm but smaller than 3 cm resected at VATS were more likely to be malignant. Nodules smaller than 0.5 cm were more likely to be benign.

Humans↗

PubMed2002

Assessment of nondiagnostic ultrasound-guided fine needle aspirations of thyroid nodules.

Thyroid nodules are common. Evaluation of patients with thyroid nodules typically includes fine needle aspiration biopsy (FNA), an approach that has proven to be accurate for the detection of thyroid cancer. Although the majority of biopsies are adequate for a cytological diagnosis, up to 20% will be insufficient or nondiagnostic. Current opinion suggests that such aspirates should be repeated, although no systematic study has investigated the usefulness of this approach, especially when ultrasound guidance is used to direct the initial FNA. We sought to define the predictors and optimal follow-up strategy for initial nondiagnostic ultrasound-guided FNAs of thyroid nodules. Data were collected for all patients at the Brigham and Women's Hospital Thyroid Nodule Clinic between 1995-2000 who underwent ultrasound-guided FNA of a thyroid nodule. All patients with nondiagnostic cytology were advised to return for a repeat ultrasound-guided FNA. Patient age, gender, nodule size, cystic content, solitary vs. multinodular thyroid, and nodule location were documented and evaluated as possible predictors of a nondiagnostic biopsy in a multivariable model. The rate of diagnostic cytology obtained on repeat ultrasound-guided FNA was calculated. A total of 1128 patients with 1458 nodules were biopsied over a 6-yr period. A total of 1269 aspirations (950 patients) were diagnostic, and 189 (178 patients) were nondiagnostic. The cystic content of each nodule was the only significant independent predictor of nondiagnostic cytology (P < 0.001). The fraction of specimens with initial nondiagnostic cytology increased with greater cystic content (P < 0.001 for trend). A diagnostic ultrasound-guided FNA was obtained on the first repeat biopsy in 63% of nodules and was inversely related to increasing cystic content of each nodule (P = 0.03). One hundred and nineteen patients with 127 nodules returned for follow-up as advised, and malignancy was documented in 5%. Despite ultrasound-guided FNA, there remains a significant risk of initial nondiagnostic cytology, largely predicted by the cystic content of each nodule. Repeat aspiration is often successful and should be the standard approach to such nodules, given their risk of malignancy.

Adult↗

PubMed2006

Software volumetric evaluation of doubling times for differentiating benign versus malignant pulmonary nodules.

OBJECTIVE: The purpose of our study was to evaluate the reliability of software-calculated doubling times for discerning malignant versus benign nodules. MATERIALS AND METHODS: CT lung analysis volumetric software was used to retrospectively calculate the doubling times of 63 solid noncalcified nodules by comparing nodule volumes on baseline and follow-up CT scans obtained a median of 3.7 months apart. A final diagnosis based on validated criteria was available for all 63 nodules. All CT examinations were performed with 1.25-mm-thick slices on a four-detector unit. Taking 500 days as the upper value for malignancies, we evaluated whether the software-calculated doubling times could be used to distinguish malignant from benign solid nodules. We also examined whether the relative volume variation of benign nodules correlated with initial nodule size, interscan interval, or differences in contrast administration or exposure parameters between baseline and follow-up CT. RESULTS: There were 52 benign and 11 malignant nodules. Benign nodules had a median doubling time of 947 days and a mean relative volume variation of -4.4% (range, -50% to 38%). Malignant nodules had a median doubling time of 117 days and a mean relative volume variation of 102% (22-462%). The sensitivity, specificity, and negative and positive predictive values of the volumetric software for diagnosing malignancy were 91% (95% confidence interval [CI], 0.59-1.00), 90% (95% CI, 0.79-0.97), 98% (95% CI, 0.89-1.00), and 67% (95% CI, 0.38-0.88), respectively. No correlation was found between the relative volume variation of benign nodules and their initial size, the interscan interval, or differences in contrast administration or exposure parameters between the two CT examinations. CONCLUSION: Software-calculated pulmonary nodule doubling times of more than 500 days have a 98% negative predictive value for the diagnosis of solid malignant pulmonary nodules. This method may be useful for diagnosing malignant pulmonary nodules on follow-up CT.

Adult↗

PubMed2003

Can color Doppler sonography aid in the prediction of malignancy of thyroid nodules?

OBJECTIVE: To determine whether color Doppler interrogation of a thyroid nodule can aid in the prediction of malignancy. METHODS: We obtained color Doppler images of thyroid nodules undergoing sonographically guided fine-needle aspiration. The color Doppler appearance of each nodule was graded from 0 for no visible flow through 4 for extensive internal flow. The size, sonographic appearance, results of fine-needle aspiration, and surgical pathologic findings, if available, were recorded for each nodule. RESULTS: There were 254 nodules sampled, of which 32 were malignant (all confirmed at surgery) and 177 were benign. Fourteen (43.8%) of the 32 malignant nodules were color type 4, compared with only 26 (14.7%) of the 177 benign nodules (P = .0004, Fisher exact test). Thirteen (40.1%) of the 32 malignant nodules were solid, as were 18 (10.2%) of the 177 benign nodules (P = .006, Fisher exact test). Among solid nodules, the prevalence of malignancy was greater when the nodule was hypervascular (13 [41.9%] of 31) than when the color type was less than 4 (11 [14.7%] of 77; P = .004, Fisher exact test). CONCLUSIONS: Solid hypervascular thyroid nodules have a high likelihood of malignancy (nearly 42% in our series). The color characteristics of a thyroid nodule, however, cannot be used to exclude malignancy, because 14% of solid nonhypervascular nodules were malignant.

Biopsy, Needle↗

PubMed2000

[Treatment of solitary toxic thyroid nodules with the use of percutaneous ethanol injections].

Twenty women aged 18-76 years (mean 42 +/- 23 years) with solitary benign toxic thyroid nodule were treated with intranodular percutaneous 96%-ethanol injection, performed under ultrasound guidance. 1 ml of ethanol was instilled per 1 cm3 of nodule tissue. 2-5 (mean 3.1) sessions were conducted every month. The early follow-up evaluation of the results (the evaluation of nodule size by means of clinical and ultrasound examination) was performed in 6 months, and the long-term one in 2 years after last injection. A morphological evaluation was conducted according to the following scale: 1--nodule disappearance, 2--cicatricial nodule (solid structure and less than 0.5 cm in diameter), 3--nodule smaller by [symbol: see text] 50% of its initial dimensions, 4--nodule smaller by < 50% of its initial dimensions. A functional evaluation was carried out according to the following scale: I--permanent euthyroidism, II--permanent decrease of hyperthyroidism, III--no functional effect. A final follow-up evaluation revealed: nodule disappearance in 2 (10%) patients (Group 1), cicatricial nodule in 8 (40%) patients (Group 2), nodules smaller by [symbol: see text] 50% of its initial dimensions in 2 (10%) patients (Group 3) and nodules smaller by < 50% of initial dimensions in 8 (40%) patients (Group 4). The results in Group 1 and 2 were defined as good (50%), in Group 3 as satisfactory (10%) and in Group 4 as bad; and I--permanent euthyroidism in 16 (80%) patients, II--permanent decrease of hyperthyroidism in 1 (5%) patient, III--no functional effect in 3 (15%) patients. 2 patients in whom new nodules appeared and 1 patient with bad morphological and no functional treatment effects were operated on. A histological examination revealed haemorrhagic necrosis surrounded by fibrous tissue in removed nodules. The following complications were observed: 1) pain during and after the injection in 15 (75%) patients, 2) subfebrile body temperature in 3 (15%) patients and fever up to 39 degrees C on the 1-st day after the injection in 1 (5%) patient, 3) local ecchymosis in 1 (5%) patient, 4) temporary dysphonia in 1 (5%) patient. It seems that percutaneous ethanol injection treatment can be an useful treatment method of solitary benign toxic thyroid nodules in patients who do not give their consent to surgical or 131I treatment or with contraindications to an operation or radioiodine therapy.

Adolescent↗

PubMed1993

Decreased expression of cytochrome P450 mRNAs and related steroid hydroxylation activities in hepatic hyperplastic nodules in male F344 rats.

To explore the mechanism(s) underlying the relationship between expression of cytochrome P450 (CYP) enzymes and growth of hepatic hyperplastic nodules, mRNA of CYP1A1, 1A2, 2B1, 2B2, 2C6, 2C11, and 3A1, and CYP enzyme-mediated hydroxylation of testosterone (T), 17 beta-estradiol (E), and corticosterone (C) were determined in a group of selected large nodules from livers of male F344 rats given the modified Solt-Farber resistance protocol and compared with control and surrounding tissue. Slot-blot analysis with specific oligonucleotides showed little or no mRNA of CYP2B1, 2B2, and 2C6 in nodules, surrounding tissue, and control liver without PB treatment. Constitutive expression of CYP1A2, 2C11, and 3A1 in nodules was from 2 to 10 times less in nodules than in control liver. BP treatment increased mRNA of CYP2B1, 2B2, 2C6, 2C11, and 3A1 in control and surrounding tissue substantially, but was 3 to 11 times less in the nodules than in the control liver. Messenger RNA of CYP1A1 was not detected in either nodules or control livers independent of PB treatment. HPLC determination demonstrated a general pattern of a decrease in CYP enzyme-mediated hydroxylation of T, E, and C in the nodules relative to the surrounding tissue and control liver. The differences between nodules and control liver were usually 3 to 10-fold for the 12 metabolites detected although smaller decreases were observed for a few metabolites in some nodules. PB increased the rate of hydroxylation for 11 of the 12 metabolites and resulted in 2 additional metabolites of both T and E in control liver and some nodules. However, the general pattern of lower hydroxylation activities in the nodules relative to the surrounding tissue remained the same as that in the non-PB group. These observations are consistent with the hypothesis that intracellular kinetics of endogenous CYP enzyme substrates may differ in some nodules, relative to the surrounding tissue, as a result of decreased expression of CYP genes. This difference in CYP expression pattern in turn may contribute to the selective growth and progression to cancer of certain nodules, as many endogenous CYP enzyme substrates are modulators of DNA and RNA synthesis and cellular growth and differentiation.

Animals↗

PubMed2004

[Clinical evaluation of a software for automated localization of lung nodules at follow-up CT examinations].

PURPOSE: To evaluate a software algorithm for automated localization of pulmonary nodules at follow-up CT examinations of the chest and to determine factors influencing the rate of correctly matched nodules. MATERIALS AND METHODS: The "real-time automatic matching" (RAM) algorithm (Siemens LungCare trade mark software) was applied to 22 follow-up multirow-detector CT (MDCT) examinations in 11 patients (Siemens Somatom VolumeZoom, tube voltage 120 kVp; effective tube current 20 mAs (n = 18) or 100 mAs (n = 4); 4 x 1 mm detector configuration, 1.25 mm slice thickness; 0.8 mm reconstruction increment; standard lung kernel B50f) with a total of 190 lung nodules (mean diameter 6.7 +/- 3.5 mm, range 2 - 17 mm). The following nodule features were recorded: diameter, edge definition (well- or ill-defined), location (upper, middle or lower third; central or peripheral; right or left lung) and inspiration level (considered identical if the difference of diaphragm-apex distance between baseline and follow-up examination was < 5 %, otherwise it was considered different). A nodule was regarded as correctly localized if the marking box drawn by the software was visible on at least one slice together with the nodule and the center of the nodule was located inside the marking box. chi(2)-test was used to describe influence of nodule features on detection rate. Influence of nodule size was assessed using Mann-Whitney-U-Test. RESULTS: RAM correctly located 164 of 190 of all lung nodules (86.3 %). Detection rate did not depend on nodule location (left vs. right lung: p = 0.48; upper vs. middle vs. lower third: p = 0.96; peripheral vs. central: p = 0.47) or diameter (p = 0.30). Influence of inspiration level was highly significant (p < 0.001): nodules were detected in 100 % (146/146) for identical inspiration levels and in 40.9 % (18/44) for different inspiration levels. The observation of a significant better localization of ill-defined nodules (p = 0.028) corresponds to a statistical artifact due to the inhomogeneous distributions of this specific feature in our data. CONCLUSION: RAM is a valuable tool for follow-up of lung nodules at CT. Only very different inspiration levels influenced detection rate.

Algorithms↗

PubMed2006

Nuclear DNA endoreduplication and expression of the mitotic inhibitor Ccs52 associated to determinate and lupinoid nodule organogenesis.

Lotus japonicus determinate nodules differ greatly from indeterminate nodules in their organogenesis and morphological characteristics, whereas Lupinus albus lupinoid nodules share features of determinate and indeterminate nodules. The mitotic inhibitor Ccs52A is essential for endoreduplication and ploidy-dependent cell enlargement during symbiotic cell differentiation in Medicago truncatula indeterminate nodules. ccs52A homolog genes were isolated from lupin and lotus nodules; the deduced Ccs52A proteins showed high sequence similarity with other Cdh-1-type activators of the anaphase-promoting complex and were grouped with A-type Ccs52 proteins from different plants. In lupin, ccs52A expression was restricted to the earlier stages of nodule development, whereas ccs52A transcripts accumulated in lotus nodule primordia and, to a lesser extent, in mature nodules. Nodule development in Lupinus albus involved a progressive increase in nuclear and cellular size and ploidy level; similarly, Lotus japonicus nodules contained polyploid nuclei and enlarged cells in the infected zone. Nevertheless, in situ hybridization experiments showed the highest ccs52A expression in the inner cortex cells of the lupin nodule primordium, probably associated to the increased size of these cells in mature nodules. In view of our results, Ccs52A-mediated endoreduplication appears to be a universal mechanism required for nodule cell differentiation during the establishment of nitrogen-fixing symbioses.

Amino Acid Sequence↗

PubMed2002

Synchronous hepatocellular carcinoma and cholangiocarcinoma arising in two different dysplastic nodules.

We present the first reported case of explant cirrhotic liver that had synchronous cholangiocarcinoma and hepatocellular carcinoma arising in two different high-grade dysplastic nodules. The patient was a 55-year-old woman who had hepatitis B virus-associated liver cirrhosis for 3 years. The moderately differentiated cholangiocarcinoma occurred in high-grade dysplastic nodule with a 1.7-fold cell density compared with that of cirrhotic nodule. The hepatocellular carcinoma arose in a nodule-in-nodule pattern within a peripherally low-grade and centrally high-grade dysplastic nodule and had a 2.7-fold cell density compared with that of cirrhotic nodule. By immunohistochemistry, the tumor cells of the cholangiocarcinoma as well as bile ductular cells in dysplastic nodule were diffusely positive for cytokeratin 7, whereas hepatocellular carcinoma cells and dysplastic hepatocytes were negative for cytokeratin 7. The c-kit-positive hepatic progenitor cells were singly scattered between hepatocytes, and their number was highest in cirrhotic nodule and decreased in dysplastic nodule, whereas they were absent in cholangiocarcinoma and hepatocellular carcinoma arising in dysplastic nodules. Proliferation indices were progressively increased in cirrhotic nodule, dysplastic nodule, and cholangiocarcinoma or hepatocellular carcinoma, sequentially. These observations indicate that cholangiocarcinoma as well as hepatocellular carcinoma can develop in dysplastic nodule and that hepatic progenitor cells might play a role in the early stage of cholangiocarcinogenesis and hepatocarcinogenesis.

Bile Duct Neoplasms↗

PubMed1992

Observation of the Oxygen Diffusion Barrier in Soybean (Glycine max) Nodules with Magnetic Resonance Microscopy.

The effects of selected gas perfusion treatments on the spinlattice relaxation times (T(1)) of the soybean (Glycine max) nodule cortex and inner nodule tissue were studied with (1)H high resolution magnetic resonance microscopy. Three gas treatments were used: (a) perfusion with O(2) followed by N(2); (b) O(2) followed by O(2); and (c) air followed by N(2). Soybean plants with intact attached nodules were placed into the bore of a superconducting magnet and a selected root with nodules was perfused with the gas of interest. Magnetic resonance images were acquired with repetition times from 50 to 3200 ms. The method of partial saturation was used to calculate T(1) times on selected regions of the image. Calculated images based on T(1) showed longer T(1) values in the cortex than in the inner nodule during all of the gas perfusions. When nodules were perfused with O(2)-O(2), there was no significant change in the T(1) of the nodule between the two gas treatments. When the nodule was perfused with O(2)-N(2) or air-N(2), however, the T(1) of both the cortex and inner nodule increased. In these experiments, the increase in T(1) of the cortex was 2- to 3-fold greater than the increase observed in the inner nodule. A similar change in T(1) was found in detached live nodules, but there was no change in T(1) with selective gas perfusion of detached dead nodules. These observations suggest that cortical cells respond differently to selected gas perfusion than the inner nodule, with the boundary of T(1) change sharply delineated at the interface of the inner nodule and the inner cortex.

Journal Article↗

PubMed1993

Soybean (Glycine max) Nodule Physical Traits Associated with Permeability Responses to Oxygen.

Nodule permeability (P) controls the amount of O2 entering the nodule and is an important determinant of N2 fixation. Modulation of water volume in the intercellular spaces of the nodule cortex was hypothesized to change the effective thickness of a diffusion barrier and account for changes in P. This hypothesis was examined by evaluating physical traits of nodules that may affect P. The first test of the hypothesis was to determine whether alterations in P may result in changing both the density and the air space content of nodules as the water content of intercellular spaces was varied. Density of nodules exposed to 21 kPa O2 increased as the time following detachment from the plant increased from 5 to 60 min. Nodules from soybean (Glycine max [L.] Merr.) plants shaded for 48 h had a lower fractional air space content than nodules from control plants. Nodule detachment and prolonged shading decreased P, and the increase in density and decrease in fractional air space content associated with decreased P in these treatments supports the proposed hypothesis. The second test of the hypothesis was to determine whether nodules released water easily in response to water potential gradients. The intrinsic capacitance of nodules determined by pressure-volume analysis was 0.29 MPa-1 and indicated that the tissue can release relatively large amounts of water from the symplast with only small changes in total nodule water potential. Estimates of the bulk modulus of elasticity ranged from 0.91 to 2.60 MPa and indicated a high degree of elasticity. It was concluded that the physical properties of nodules were consistent with P modulation by the release and uptake of intercellular water in the nodule cortex.

Journal Article↗

PubMed1982

Synthesis and accumulation of nitrite in soybean nodules supplied with nitrate.

Nodulated soybean plants (Glycine max [L.] Merr) were grown in sand culture without combined N or with a continuous supply of nitrate in nutrient solution. Moderate nitrate concentration (30 milligrams N per liter) had little effect on nodule weight/plant while high nitrate concentration (100 milligrams N per liter) depressed nodule weight/plant by 70 to 80% with harvests 30 to 60 days after planting and initiation of nitrate treatments.The effect of nitrate supply on ammonium, amino, and ureide nitrogen concentrations in nodules was small and inconsistent. In contrast, nitrate and nitrite concentrations in nodules were directly proportional to nitrate supply and inversely proportional to nodule weight/plant. Correlations between nitrate or nitrite concentration in nodules and nodule weight/plant were highly significant.Cytosol from soybean nodules was found to contain NADH-dependent nitrate reductase activity (typical activity was 0.1 micromole per milligram protein x hour). A Rhizobium japonicum mutant (derived from strain 61A76) lacking nitrate reductase was employed to show that the cytosol enzyme activity is of host origin. Growth of nodules formed by the mutant lacking nitrate reductase was inhibited by nitrate. These nodules did contain nitrite although concentrations of nitrite (about 0.3 microgram N per gram fresh weight) were low relative to nitrite concentrations (about 1.5 microgram N per gram fresh weight) in nodules formed by R. japonicum strain 61A76. The overall results support the idea that the depression of legume nodule growth by nitrate is directly related to the metabolism of nitrate in nodules.

Journal Article↗