[CT-guided radiofrequency (RF) ablation of osteoid osteoma: clinical long-term results]. / CT-gesteuerte Radiofrequenz (RF)-Ablation von Osteoidosteomen: klinische Langzeitergebnisse.

PURPOSE: To evaluate CT-guided radiofrequency (RF) ablation of osteoid osteoma using internally cooled monopolar RF electrodes for technical success, complications and clinical long-term success. MATERIALS AND METHODS: Between April 1999 and July 2006, 23 patients were treated under general anesthesia with CT-guided RF ablation using an internally cooled monopolar single RF electrode (Cool-tip, Valleylab, TycoHealthcare, Boulder, USA; active tip: 10 mm). For the removal of the nidus, we used either a manual or an automated drill. The technical success was evaluated by a CT scan (MSCT, Siemens Medical Solutions, Forchheim). The clinical long-term success was investigated by questioning patients prior to discharge, and after 6, 12 and 18 months. After 18 months, patients were interviewed on an annual basis. RESULTS: The technical success rate was 100 %. The nidus was located in n = 19 cases at the lower extremity and in n = 4 cases at the upper extremity. Minor complications were observed for n = 2 patients. The mean hospitalization time was 1.5 d (1-2 d). The mean follow-up was 75.9 months (18-120 months) for n = 23 patients. No local recurrence was observed. One patient had intermediate pain one week after RF ablation without recurrent symptoms. CONCLUSION: CT-guided RF ablation using an internally cooled monopolar single RF electrode is an effective and safe minimally invasive method for the treatment of osteoid osteoma with excellent clinical long-term success.

[Diagnosis of fever of unknown origin (FUO). Positron emission tomography/computed tomography (PET-CT)]. / Diagnostik bei Fieber unklarer Genese (FUO) - Positronen-Emissions-Tomographie/Computertomographie(PET-CT).

Nuclear medicine imaging is now well accepted for the localization of septic foci. But in patients the results of infection scintigraphy, radiology and ultrasound remain unsatisfactory in the diagnosis of fever of unknown origin (FUO). In contrast to septic infections, patients with FUO - mostly in elderly patients - tend to have such conditions as occult tumours, atypical pneumonia, hematoblastosis, malignant lymphomas. (18)F(Fluor-18)-Fluordeoxyglucose-PET ((18)F-FDG PET) has made it possible to localize symptomatically occult changes with a high diagnostic accuracy and to achieve differentiation between benign and malignant changes.

Chromosome polymorphism and complements in populations of Girardia species (Platyhelminthes, Tricladida, Paludicola) from southern Brazil

The karyotypes of four species of freshwater triclads of the genus Girardia (Platyhelminthes), i.e. G. schubarti, G. tigrina, G. anderlani, and G. biapertura, from populations of different localities of the Rio Grande do Sul State, in southern Brazil, were analyzed. The karyotype of G. biapertura is presented for the first time. Three basic complements of 4, 8, and 9 chromosomes were found. Diploids, triploids, or mixoploids (2n/3n) specimens were frequently detected in these populations. The basic chromosomal complement of n = 9 was verified in two different species (G. biapertura and G. anderlani), presenting a large acrocentric chromosome which is rare in the family Dugesiidae. An intra and interspecific chromosomal variability was also detected and its evolutionary implications are discussed.

Os cariótipos de quatro espécies de planárias de água doce do gênero Girardia (Platyhelminthes), a saber, G. schubarti, G. tigrina, G. anderlani e G. biapertura, de populações ocorrentes em diferentes locais do estado do Rio Grande do Sul, na região sul do Brasil, foram analisados. O cariótipo de G. biapertura é apresentado pela primeira vez. Foram observados três complementos básicos, de 4, 8 e 9 cromossomos. Espécimes diplóides, triplóides e mixoplóides (2n/3n) foram observados freqüentemente nessas populações. O complemento cromossômico básico de n = 9 foi verificado em duas espécies (G. biapertura e G. anderlani), apresentando um grande cromossomo acrocêntrico que é raro na família Dugesiidae. Também foi observada certa variabilidade cromossômica, tanto intra- como interespecífica, cujas implicações evolutivas são discutidas.

Chromosome polymorphism and complements in populations of Girardia species (Platyhelminthes, Tricladida, Paludicola) from southern Brazil

The karyotypes of four species of freshwater triclads of the genus Girardia (Platyhelminthes), i.e. G. schubarti, G. tigrina, G. anderlani, and G. biapertura, from populations of different localities of the Rio Grande do Sul State, in southern Brazil, were analyzed. The karyotype of G. biapertura is presented for the first time. Three basic complements of 4, 8, and 9 chromosomes were found. Diploids, triploids, or mixoploids (2n/3n) specimens were frequently detected in these populations. The basic chromosomal complement of n = 9 was verified in two different species (G. biapertura and G. anderlani), presenting a large acrocentric chromosome which is rare in the family Dugesiidae. An intra and interspecific chromosomal variability was also detected and its evolutionary implications are discussed.

Os cariótipos de quatro espécies de planárias de água doce do gênero Girardia (Platyhelminthes), a saber, G. schubarti, G. tigrina, G. anderlani e G. biapertura, de populações ocorrentes em diferentes locais do estado do Rio Grande do Sul, na região sul do Brasil, foram analisados. O cariótipo de G. biapertura é apresentado pela primeira vez. Foram observados três complementos básicos, de 4, 8 e 9 cromossomos. Espécimes diplóides, triplóides e mixoplóides (2n/3n) foram observados freqüentemente nessas populações. O complemento cromossômico básico de n = 9 foi verificado em duas espécies (G. biapertura e G. anderlani), apresentando um grande cromossomo acrocêntrico que é raro na família Dugesiidae. Também foi observada certa variabilidade cromossômica, tanto intra- como interespecífica, cujas implicações evolutivas são discutidas.

Chromosome polymorphism and complements in populations of Girardia species (Platyhelminthes, Tricladida, Paludicola) from southern Brazil.

The karyotypes of four species of freshwater triclads of the genus Girardia (Platyhelminthes), i.e. G. schubarti, G. tigrina, G. anderlani, and G. biapertura, from populations of different localities of the Rio Grande do Sul State, in southern Brazil, were analyzed. The karyotype of G. biapertura is presented for the first time. Three basic complements of 4, 8, and 9 chromosomes were found. Diploids, triploids, or mixoploids (2n/3n) specimens were frequently detected in these populations. The basic chromosomal complement of n=9 was verified in two different species (G. biapertura and G. anderlani), presenting a large acrocentric chromosome which is rare in the family Dugesiidae. An intra and interspecific chromosomal variability was also detected and its evolutionary implications are discussed.

Differentiation between malignant and benign solitary pulmonary nodules with proton density weighted and ECG-gated magnetic resonance imaging.

OBJECTIVE: To estimate performance of MRI for differentiating malignant from benign solitary pulmonary nodules (SPN) using morphological characteristics. MATERIAL AND METHODS: MRI in 46 patients with SPN (mean diameter: 19 mm) was carried out on 1.0 Tesla scanner using ECG-gated, gradient echo sequence. Morphological signs of SPN were determined and compared with previously performed helical-CT, where final diagnosis served as reference with 52% frequency of malignancy. Furthermore, three observers evaluated all images. RESULTS: Significant differences between the two groups were found for nodules shape, margin, inhomogeneity and the vessel-sign in MRI, nodules shape, margin, the vessel-sign, and presence of spicules in CT. Using these signs, AUC were 0.746 for MRI and 0.765 for CT. The mean sensitivity, specificity, and accuracy of observers for MRI/CT were 89%/95%, 42%/41%, 66%/68%, respectively. CONCLUSIONS: Despite discrepancies in morphologic appearance, no significant difference of accuracy between MRI and CT was determined. Further investigations are necessary to demonstrate the clinical use in combination with functional parameters, establishing MRI as a comprehensive diagnostic modality for SPN.

[Detection of pulmonary nodules with breath-hold magnetic resonance imaging in comparison with computed tomography]. / Detektion von Lungenrundherden mit der Magnetresonanztomographie in Atemanhaltetechnik im Vergleich zur Spiral-Computertomographie.

PURPOSE: Evaluation of sensitivity and false positive findings of two fast MRI sequences for the detection of pulmonary nodules in comparison with spiral CT by two independent observers. MATERIALS AND METHODS: All 30 enrolled patients had a spiral CT or MSCT as base line study. MRI was performed with a 1.5 T MR scanner (Sonata, Siemens) using a transverse 3D gradient echo sequence (3D-GRE: TR/TE/flip = 2.9 ms/1.1 ms/5 degrees ) and a half-Fourier single-shot fast spin-echo sequence (HASTE: TR/TE/flip = 800/25/150 degrees ) acquired in three planes. A separate analysis for both sequences was carried out prospectively by two independent readers (A and B) with different experience regarding pulmonary MRI. Additionally, a retrospective reading with knowledge of the CT scans was done. Results were calculated for all lesions and for lesions larger than 4 mm. RESULTS: The sensitivities were 73 %, 70 % and 84 % for the 3D-GRE sequence (reader A, reader B, retrospective reading) and 65 %, 68 % and 81 % for the HASTE sequence. For lesions larger than 4 mm, the sensitivities were 93 %, 89 %, 96 % for the 3D-GRE sequence and 85 %, 85 %, 96 % for the HASTE sequence. The rate of false positive findings depended on the reader's experience, but was generally lower for the 3D-GRE sequence with 2 and 16 (reader A and B) false positive nodules compared to 4 and 40 false positive findings for the HASTE sequence. The 3D-GRE sequence was more accurate for both readers (reader A: p = 0.08, reader B: p = 0.00003). CONCLUSION: The sensitivity of MRI for the detection of lung nodules was only acceptable for lesions larger than 4 mm. The 3D-GRE sequence is superior to the HASTE sequence due to the reduced amount of false positive findings with comparable sensitivity.

Uncommon case of a foreign body ingestion with consecutive small-bowel obstruction in a child.

A 12-year-old boy with Lennox syndrome presented with an acute abdomen and a history of progressive abdominal pain and vomiting over 3 weeks. The uncommon finding in this case was a foreign body detected in a lower loop of the jejunum causing radiological and clinical signs of jejunitis/ileitis. The foreign body had to be removed surgically and turned out to be a hard (originally soft) plastic part of a towel rack.

Evaluation of genotoxicity through micronuclei test in workers of car and battery repair garages

In this study, the micronuclei test (MNT) was applied in exfoliated cells of buccal mucosa, in order to evaluate the genotoxic risk associated with occupational exposure of mechanics, storage battery renovation workers, and car painters. For each individual, 3000 exfoliated buccal cells were analyzed. There was a significantly higher frequency of micronucleated cells (MNC) in the exposed workers than in controls. Smoking and drinking habits, age, and working time did not represent significant factors in terms of increasing the production of micronuclei (MN), when the control and the exposed groups were compared. These results allowed to conclude that the studied individuals belong to a risk group and should periodically undergo biological monitoring and proper care

Evaluation of the genotoxic effect of rutin and quercetin by comet assay and micronucleus test.

Flavonoids are phenolic compounds, naturally found in vegetables, tea and red wines. A recent study has demonstrated that the flavonoids rutin and quercetin show a protective role against the deleterious effects of free radicals in cirrhotic rats. Considering this finding and the controversial results concerning the mutagenicity of rutin and quercetin recorded in the literature, the capacity of these flavonoids to cause damage to the DNA was evaluated using the alkaline single-cell gel electrophoresis (SCG) and micronucleus test in the bone marrow of mice. The doses for both compounds were 2 x 2500, 2 x 1250 and 2 x 625 mg/kg. Micronucleus test showed that rutin caused no damage to the DNA of the mice bone marrow cells, and the SCG assay demonstrated an increase of damage only at the dose of 2 x 1250 mg/kg. But when the mice cells of the three quercetin doses were compared with the negative control, significantly higher damage was observed by SCG assay, although not proportional to the dose. The micronucleus test also demonstrated a significant increase of damage, but only at the 2 x 1250 mg/kg dose. Considering the results obtained in this study with very high doses, it is unlikely that the consumption of rutin and quercetin produces any clastogenic effects. Our results also indicated that SCG could profitably be used in drug genotoxicity evaluation protocols.

[CT-guided therapy of osteoid osteoma by drill trepanation of the nidus. Clinical follow-up results]. / CT-gesteuerte Therapie des Osteoidosteoms durch Nidusbohrung: Klinische Langzeitergebnisse.

PURPOSE: Evaluation of technical success and follow-up of patients with osteoid osteoma. MATERIAL AND METHODS: 9 patients (3 w, 6 m) with a mean age of 22.3 years suffering from an osteoid osteoma localized in the femur were treated with a combination therapy based on drill trepanation of the nidus and subsequent installation of 1-2 ml ethanol (96%). The treatment was done under CT-guidance in general anaesthesia. RESULTS: During the follow-up period of 20.6 months (10 to 39 months) one relapse occurred within 3 months. This was treated with the same percutaneous method. CONCLUSIONS: Percutaneous removal of intracortical osteoid osteomas under CT-guidance had success in this study, was technical easy, and a had low relapse rate. In addition the duration of hospitalisation is shorten. Meanwhile other studies have used additive ablation with radiofrequency. A second study has been started in our department using a thermoablative procedure. In a comparison between surgical and radiological methods, the rates of relapse are similar (9% vs. 23% surgically). The CT-guided removal of intracortical osteoid osteomas should be the procedure of first choice.

Genotoxic effects of copper sulphate in freshwater planarian in vivo, studied with the single-cell gel test (comet assay).

The alkaline single-cell gel electrophoresis, or comet assay, was used to evaluate the genotoxic potential of copper sulphate in planarians. Concentration-related increase in DNA damage was induced after 2h and 7 days exposure to CuSO4 dissolved in culture water. To study the influence of copper ions on the persistence of mutagen-induced DNA lesions, planarians were treated with methyl methanesulphonate (MMS), and further incubated in the absence (post-incubation) or presence (post-treatment) of CuSO4. After 2h of post-treatment enhanced persistence of DNA effects in relation to the corresponding post-incubation value was detected, which indicate inhibition of DNA repair by CuSO4. At 4h an increase of DNA migration in relation to the 2h value was observed, which is significant for the post-incubation group. After 24h, DNA damage decreased but was still significantly elevated in relation to the control. From our results, we conclude that planarians are suitable organisms for in vivo detection of copper genotoxicity in the comet assay, and can be used to assess both acute and chronic exposure to this chemical in aquatic ecosystems. The inhibition effect of copper ions on repair of MMS-induced DNA damage suggests that copper could modulate the genotoxic effects associated with complex mixture exposure in the environment.

Evaluation of basal micronucleus frequency and hexavalent chromium effects in fish erythrocytes.

Hexavalent chromium (Cr [VI]) genotoxicity was studied using fish micronucleus analysis in peripheral blood erythrocytes from Pimephales promelas, the fathead minnow. Forty-five- to 60-d-old fish were used to assess the spontaneous level of genotoxic damage. The genotoxic effect of Cr (VI) obtained from potassium dichromate (K2Cr2O7) in tests performed for 7-, 14-, and 21-d exposure periods was estimated. Significant micronucleated erythrocyte (MNE) induction was detected in fish exposed for 7 d to 2.5 mg/L of Cr (VI), and induction decreased after 21 d of exposure. The results suggest a handling effect in fish manipulated compared to those not manipulated, thus demonstrating the importance of including parallel negative controls in experimental design. Basal levels of MNE are reported, providing laboratory values for future assay quality control. The importance of determining the period with the highest expression of the genotoxic effects in this assay system was also confirmed.

Genomic instability in Down syndrome and Fanconi anemia assessed by micronucleus analysis and single-cell gel electrophoresis.

Cytokinesis-block micronucleus (CB-MN) assay and single-cell gel electrophoresis (SCGE) were employed to analyze leukocytes from 14 Fanconi anemia (FA) patients, 30 Down syndrome (DS) patients, and 30 control individuals, to examine the sensitivity of these techniques to detect genomic instability in these 2 diseases. The DS patients presented increased DNA damage as measured by SCGE in relation to controls. The frequencies of micronuclei and dicentric bridges were similar to those of controls. Micronucleus frequency, dicentric bridge frequencies, and DNA damage were higher in FA patients than in controls. The high frequency of micronuclei observed in FA patients seems to be due to clastogenic events, because an increase in the frequency of dicentric bridges was also observed. Micronuclei are expressed mutations and need cell division to appear. The damage detected by SCGE is repairable, and does not require cell division. Under alkaline conditions, SCGE assesses double- and single-strand breaks and alkali-labile sites. The 2 methods are efficient for monitoring mutagenic events in exposed populations or in individuals with genetic instability. While the damage measured by micronucleus analysis is accumulated over a long period of time, DNA damage measured by SCGE reflects recent, unrepaired events.

Assessment of DNA damage in lymphocytes of workers exposed to X-radiation using the micronucleus test and the comet assay.

The mutagenic and carcinogenic effects of genotoxic agents on exposed people have constituted an increasing concern. Therefore, the objective of this work was to assess DNA damage in lymphocytes of workers exposed to X-radiation using the cytokinesis-blocked micronucleus test and the comet assay (single-cell gel electrophoresis), and to compare these two techniques in the monitoring of exposed populations. The cytokinesis-blocked micronucleus test and the comet assay were employed in the monitoring of 22 workers occupationally exposed to X-radiation in a hospital in southern Brazil. The frequency of dicentric bridges was also measured. The results of both assays and the frequency of dicentric bridges revealed a significant increase in genetic effects on the cells of exposed individuals. Age was significantly correlated with micronucleus frequency and damage index in the comet assay. The concomitant analysis of dicentric bridges when determining micronucleus frequency does not require much extra work, and may serve as a reference to the type of mutagenic effect (clastogenic or aneugenic). The combination of the alkaline comet assay with the cytokinesis-blocked micronucleus test appears to be very informative for the monitoring of populations chronically exposed to genotoxic agents.

Genotoxic effects of the alkaloids harman and harmine assessed by comet assay and chromosome aberration test in mammalian cells in vitro.

Harman and harmine are beta-carboline alkaloids which are present in plants widely used in medical practice, in beverages used for religious purposes in Brazil, as well as in tobacco smoke and over cooked food. In view of the controversial results observed in the literature about the mutagenic effects of these alkaloids, we studied their cytotoxic and genotoxic effects in V79 Chinese hamster lung fibroblasts in vitro using single-cell gel assay, Comet assay, either in the presence or in absence of an exogenous metabolic activation system (S9-mix), and by the chromosome aberration test without S9-mix. Harmine was more cytotoxic than harman. Both harman and harmine increased aberrant cell frequency and induced DNA damage by the Comet assay. These results suggest that harman and harmine are genotoxic in V79 cells, probably as a consequence of their ability to induce DNA strand breaks.

Follow-up study of the genetic damage in lymphocytes of pharmacists and nurses handling antineoplastic drugs evaluated by cytokinesis-block micronuclei analysis and single cell gel electrophoresis assay.

A follow-up study was carried out 4 years after an initial evaluation of the micronucleus frequency in 10 healthy individuals who had been occupationally exposed to antineoplastic drugs in a Brazilian hospital. Upon the first evaluation, these 10 exposed individuals were compared with 10 non-exposed individuals matched for age, sex and smoking habits; the results revealed that the frequency of micronucleated lymphocytes in individuals exposed to antineoplastic drugs was significantly higher (P=0.038) than in controls. The frequency of dicentric bridges was also increased, although not significantly (P=0.0545). After the first analysis, the workers handling antineoplastic drugs were advised to modify their work schedule to limit exposure, and the number of workers in the group was increased from 10 to 12 individuals. In the follow-up study, 12 individuals from the same work area were assessed. In addition to micronucleus frequency, alkaline single cell gel electrophoresis was also used to monitor genetic hazard. This exposed group was compared to 12 non-exposed workers from the same hospital, matched for age, sex and smoking habits. In the follow-up study, no statistical difference was found between exposed workers and controls in terms of micronucleus and dicentric bridge frequency with the Mann--Whitney U-test (P=0.129 and 0.373, respectively). However, the mean value of SCGE analysis was significantly higher in the exposed group than in the controls (P=0.0006). Although the micronucleus analysis seems to be less sensitive to assess DNA damage, it detects chromosome aberrations and not just repairable DNA breakage and alkali-labile sites. Combination of the alkaline single cell gel electrophoresis and cytokinesis blocked micronucleus assay appears to be commendable to monitor populations chronically exposed to genotoxic agents.

Effects of chronic exposure to coal in wild rodents (Ctenomys torquatus) evaluated by multiple methods and tissues.

Rio Grande do Sul (RS) coal is low quality and typically obtained by strip mining. In a recent study concerning 2 years of biomonitoring in coal regions, we demonstrated the genotoxicity of coal and related products on blood cells of native rodents, from RS, Brazil. With the goal of studying the variations in the effects of RS coal on different tissues of the same rodent, we utilized, besides the single cell gel (SCG) and micronucleus (MN) assay on blood, histological analyses and SCG assay of bone marrow, spleen, kidney, liver and lung cells, and MN assay of bone marrow and spleen cells. In addition, to identify agents that can potentially influence the results, concentrations of several heavy metals were analyzed in livers and in soil, and the total concentration of hydrocarbons in the soil was determined. Rodents exposed to coal were captured at two different sites, Butiá and Candiota, in RS. Reference animals were obtained from Pelotas, where there is no coal mining. This report provides chemical and biological data from coal regions, indicating the possible association between Zn, Ni, Pb and hydrocarbons in the induction of DNA damage (e.g. single strand-breaks and alkali-labile sites) determined by the alkaline SCG assay in cells from Ctenomys torquatus. The results of the present SCG study indicate that coal and by-products not only induce DNA damage in blood cells, but also in other tissue cells, mainly liver, kidney and lung. Neither the MN assay nor histopathological observations showed significant differences; these analyses may be useful under circumstances where genotoxicity is higher. In conclusion we believe that the in vivo genotoxicity of coal can be biomonitored by the SCG assay, and our studies suggest that wild rodents, such as C. torquatus are useful for monitoring genotoxic damage by both methods, the SCG assay and the MN test.

Genotoxicity biomonitoring in coal regions using wild rodent Ctenomys torquatus by Comet assay and micronucleus test.

Coal is a mixture of a variety of chemicals, especially hydrocarbons, which may give rise to polycyclic aromatic hydrocarbons (PAH). Many PAH compounds produce mutagenic and carcinogenic effects. The quality of mineral coal in Rio Grande do Sul (RS) is low and it is typically obtained by stripping operations; it represents approximately 87% of the Brazil reserves. This report concerns the application of the Comet assay to Ctenomys torquatus to detect the effects of coal, comparing the results with a micronucleus (MN) assay, both using peripheral blood. This study was performed over a 2-year period in an attempt to evaluate seasonal patterns. The wild rodent is fossorial, and its geographic distribution in RS coincides with the distribution of coal reserves. Three localitions were studied: two coal fields, Butiá (in a strip coal mine region) and Candiota (near a strip coal mine), and one control region, Pelotas (no coal). At the end of 2 years, 240 rodents had been analyzed. Our results showed that coal and derivatives induced DNA and chromosomal lesions in rodent cells that were demonstrated by Comet and MN assays. These tests also demonstrated quantitative differences between field exposures (Candiota > Butiá). The Comet assay was more sensitive and also showed a direct relationship between age and damage, and an inverse relationship between temperature and damage index.

Cytogenetic evaluation of aquatic genotoxicity in human cultured lymphocytes.

This paper presents the results of a cytogenetic study to evaluate the quality of Caí river water at the area under the influence of the Petrochemical Complex of the State of Rio Grande do Sul. Cytokinesis-block micronucleus assay (CBMN) was performed on cultured human lymphocytes exposed to stream water samples. The Caí River is an important tributary to the Guaíba basin that includes Porto Alegre, the capital of Rio Grande do Sul. The Caí river water is the source of drinking water after conventional treatment, and is also used for irrigation and primary contact recreation according to Federal regulations. Water samples were collected in the Caí River and some tributaries at four sites for 20 months with a bimonthly frequency, in a total of 11 samplings, from November 1993 to July 1995. It was possible to detect the presence of substances with clastogenic and/or aneugenic potential in vitro human lymphocytes at the different sites analyzed. As to the four sites studied, site B presents nearly half of the total positive results (44%), followed by sites A (28%), D (17%) and C (11%). The CBMN assay in human lymphocytes was a sensitive cytogenetic approach for aquatic environmental studies, and should be better exploited to monitor industrial areas.