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PubMed1993

Distal radio-ulnar ligament motion during supination and pronation.

The dorsal and palmar distal radio-ulnar ligaments (DRUL) play an important role in the stability of the distal radio-ulnar joint (DRUJ). Various authorities, however, hold opposite opinions regarding DRUL motion during DRUJ pronation and supination, thus implying opposite techniques for reconstruction of the unstable DRUJ. With the hypothesis that relative displacement would increase in the dorsal DRUL during pronation and would increase in the palmar DRUL during supination, measurements were made of the relative DRUL displacement with a Hall-effect displacement transducer during DRUJ pronation and supination in six fresh cadaver wrists. The hypothesis was confirmed that the dorsal radio-ulnar ligament undergoes relative displacement during pronation, while the palmar radio-ulnar ligament undergoes relative displacement during supination.

Aged↗
PubMed1994

Predicting palmar radio-carpal ligament disruption in fractures of the distal articular surface of the radius involving the palmar cortex.

12 adult cadaver wrists were dissected to identify the regions of origin of the four palmar radio-carpal ligaments. A non-dimensionalized value, called the radio-carpal ligament ratio (RLR), was defined as the width of ligament origin from the radius divided by the length of the capitate. Both values were measured directly from radiographs of the cadaver specimens. The RLRs for the four palmar radio-carpal ligaments were found to be statistically consistent. We applied the RLR concept retrospectively to 20 wrists with intraarticular distal radius fractures requiring open reduction. It was found that those fracture patterns in which the fracture fragment ratios (FFR: widths of the fracture fragments divided by the length of the capitate) were outside the limits of corresponding RLRs had clear intra-operative evidence of palmar radio-carpal ligament disruption, while those with FFRs within the limits of corresponding RLRs were noted to have no ligament disruption.

Adult↗
PubMed2006

Intraoperative, radio-guided sentinel lymph node mapping in 110 nonsmall cell lung cancer patients.

BACKGROUND: Sentinel lymph node identification has been tested in lung cancer patients with conflicting results. The present study was designed to assess the sensitivity, negative predictive value, and accuracy of intraoperative sentinel lymph node mapping by means of a radio-guided method in patients with nonsmall cell lung cancer to find the most appropriate definition of sentinel lymph node and to evaluate the usefulness of different particle sizes of radiocolloid. METHODS: One hundred ten patients with clinically N0 nonsmall cell lung cancer were enrolled in the pilot study of intraoperative sentinel node identification. Four quadrants of the peritumoral tissue were injected with 2 mL of 0.5 mCi technetium-99m suspension. Four radiocolloids of different particle size were used. After complete lymphadenectomy, all resected lymph nodes were examined with hematoxylin-eosin staining. All sentinel nodes negative for metastases by routine staining were searched further for metastatic deposits with both serial sections and immunohistochemistry for cytokeratins. RESULTS: The radio-guided method had a high identification rate, a high sensitivity, and a high negative predictive value (100%, 87%, and 93%, respectively) when immunohistochemistry was considered. When standard hematoxylin and eosin staining was applied, sensitivity and negative predictive value of sentinel lymph node labeling was lower (74% and 89%, respectively). No significant differences were found in either the sensitivity or negative predictive value among the colloid solutions of different particle size used in radio labeling, although smaller particles have shown a tendency to produce better results. CONCLUSIONS: The radio-guided technique provides efficient sentinel lymph node identification in lung cancer. Further studies are warranted to confirm the clinical utility of this strategy.

Adult↗
PubMed2004

Effects of neoadjuvant radio-chemotherapy on 18F-FDG-PET in esophageal carcinoma.

AIM: To investigate whether results of [F-18]-fluorodeoxy-d-glucose (FDG) positron emission tomography (PET) of esophageal cancer (EC) before and after neoadjuvant radio-chemotherapy correlate with histopathology after esophageal resection. METHODS: Twenty consecutive patients with EC without distant metastases were examined twice with 18F-FDG-PET during primary staging and after neoadjuvant radio-chemotherapy. FDG standardised uptake values (SUV) were correlated with the histopathological findings (percentage of viable tumour cells, tumour regression grade 1-5). RESULTS: Regression analysis revealed a slight (not significant) positive correlation between SUV(pre) (R=0.41, p=0.08) and SUV(post) (R=0.37, p=0.11) and the percentage of viable tumour cells in the resectate. Although all patients showed a significant decrease in SUV after radio-chemotherapy (p < 0.01) the percentual decrease of the SUV after therapy (DeltaSUV%) did not significantly differ between the TRG-groups. In 12 of 20 patients (60%), therapy-induced esophagitis was detected in post-therapeutic PET images. CONCLUSION: In EC, a higher pre-therapeutic SUV might be correlated with a higher fraction of vital tumour cells remaining after radio-chemotherapy. Applying the neoadjuvant therapy protocol and the study design used in this examination, there is no correlation between decrease in SUV and histopathology.

Adenocarcinoma↗
PubMed2004

Role of 2'-2' difluorodeoxycytidine (gemcitabine)-induced cell cycle dysregulation in radio-enhancement of human head and neck squamous cell carcinomas.

BACKGROUND AND PURPOSE: To try to get a better insight on the interaction between dFdC and ionizing radiation at the cellular level, we examined in vitro the effect of dFdC on the cell cycle of two human head and neck squamous cell carcinoma cell lines (SQD9 and SCC61). PATIENTS AND METHODS: Experimental conditions yielding radio-enhancement were used. Confluent cells were incubated with dFdC (5 microM) for different incubation times, washed, pulse-labeled with BrdUrd (10 microM), fixed and then processed for flow cytometry analysis. Alternatively, cells preincubated or not with dFdC were irradiated (5Gy) in drug-free medium, incubated at 37 degrees C for various times and then processed for flow cytometry analysis. RESULTS: In both cell lines, dFdC incubated between 1 and 6 h induced a DNA synthesis inhibition with accumulation of cells in the G1-S boundary followed, when DNA reinitiated, by a synchronous progression of cells throughout the cycle. A slightly different kinetics was observed in the two cell lines. A weak correlation between dFdC radio-enhancement and distribution of cells in the cell cycle was observed. It was also observed that for longer dFdC incubation times, DNA synthesis could reinitiate while cells were still incubated with dFdC. This reinitiation could be correlated with a decrease in the intracellular dFdCTP pool to non-inhibitory levels. Finally in both cell lines, dFdC modified neither the importance nor the kinetics of the radiation-induced G1 delay. CONCLUSIONS: This study provides evidence that gemcitabine used at radio-enhancing concentration induces alteration of cell kinetics and cell redistribution throughout the cell cycle. This effect is cell line-dependent. However, the weak correlation between dFdC radio-enhancement and cell cycle distribution suggests that the cell cycle effect does not constitute the most important mechanism of interaction with ionizing radiation. Our study also indicated that in the two cell lines studied, a modulation of the G1-S checkpoint was not implicated in enhancement of radiation response by dFdC.

Carcinoma, Squamous Cell↗
PubMed1999

In vitro cytocompatibility of radio-opacifiers used in ureteral endoprosthesis.

Ureteral endoprostheses are urinary catheters made of polymeric biomaterials made radio-opaque through the addition of X-ray absorbing additives such as barium, bismuth, tantale or tungsten. The aim of this work was to study the in vitro toxicity of solutions of these radio-opacifiers using two cell culture models. Primary-cultures of human urothelial cells (HUC) arising from normal adult urinary tract and permanent urothelial cell line were used. Solutions at different dilutions were placed into the wells containing monolayers of confluent cells. After 24 h incubation period, the solutions were removed and cell viability and cell metabolic activity tests were performed (Neutral Red assay and MTT assay). At a concentration lower than 1 mg l(-1) the different radio-opacifiers used showed no toxicity. From 1 to 3 mg l(-1) one can note a significant dose-dependent decrease of cell metabolic activity of solely HUC for barium chloride. At 3 mg l(-1) one can note a significant deleterious effect on HUC metabolic activity, with bismuth and tantale. For tungsten, there is no deleterious effect, but on the contrary a significant increase in HUC metabolic activity at a 0.5 mg l(-1) concentration. None of the solutions did provoke alterations in HUC viability for concentrations less than 3 mg l(-1). Interestingly, for permanent cell line one can note a solely significant decrease of cell viability at 3 mg l(-1) for tantale. All the other tested salts on permanent cell line were not significantly different from controls for cell viability as well as cell metabolic activity. HUC culture model may be of relevance for the screening of radio-opacifiers intended for ureteral endoprostheses.

Adult↗
PubMed1999

Improvement of the mechanical properties of acrylic bone cements by substitution of the radio-opaque agent.

Acrylic bone cements become radio-opaque by the addition of an inorganic compound, commonly BaSO4 or ZrO2. However, the use of these additives has some negative effects such as loss of mechanical properties, risk of release and bone resorption. The use of the monomer 2,5-diiodo-8-quinolyl methacrylate (IHQM), which shows adequate polymerization and radio-opacity properties, is proposed as a new X-ray opaque, methacrylate iodine-containing agent. The aim of this study is to determine the effect of this new radio-opaque agent on the mechanical properties of acrylic bone cements. The addition of the iodine-containing methacrylate provides a statistically significant increase in the tensile strength, fracture toughness and ductility, with respect to the barium sulphate-containing cement. This effect can be attributed to the fact that the use of a radio-opaque monomer eliminates the porosity associated with the barium sulfate particles, which show no adhesion to the matrix. However, some reinforcing effect must also be attributed to the iodine-containing monomer, since the tensile and fracture toughness values reached are even higher than those shown by the radiolucent cement.

Journal Article↗
PubMed2002

Control of Jupiter's radio emission and aurorae by the solar wind.

Radio emissions from Jupiter provided the first evidence that this giant planet has a strong magnetic field and a large magnetosphere. Jupiter also has polar aurorae, which are similar in many respects to Earth's aurorae. The radio emissions are believed to be generated along the high-latitude magnetic field lines by the same electrons that produce the aurorae, and both the radio emission in the hectometric frequency range and the aurorae vary considerably. The origin of the variability, however, has been poorly understood. Here we report simultaneous observations using the Cassini and Galileo spacecraft of hectometric radio emissions and extreme ultraviolet auroral emissions from Jupiter. Our results show that both of these emissions are triggered by interplanetary shocks propagating outward from the Sun. When such a shock arrives at Jupiter, it seems to cause a major compression and reconfiguration of the magnetosphere, which produces strong electric fields and therefore electron acceleration along the auroral field lines, similar to the processes that occur during geomagnetic storms at the Earth.

Journal Article↗
PubMed2003

Nanosecond radio bursts from strong plasma turbulence in the Crab pulsar.

The Crab pulsar was discovered by the occasional exceptionally bright radio pulses it emits, subsequently dubbed 'giant' pulses. Only two other pulsars are known to emit giant pulses. There is no satisfactory explanation for the occurrence of giant pulses, nor is there a complete theory of the pulsar emission mechanism in general. Competing models for the radio emission mechanism can be distinguished by the temporal structure of their coherent emission. Here we report the discovery of isolated, highly polarized, two-nanosecond subpulses within the giant radio pulses from the Crab pulsar. The plasma structures responsible for these emissions must be smaller than one metre in size, making them by far the smallest objects ever detected and resolved outside the Solar System, and the brightest transient radio sources in the sky. Only one of the current models--the collapse of plasma-turbulent wave packets in the pulsar magnetosphere--can account for the nanopulses we observe.

Journal Article↗
PubMed2005

Detection of a radio counterpart to the 27 December 2004 giant flare from SGR 1806-20.

It was established over a decade ago that the remarkable high-energy transients known as soft gamma-ray repeaters (SGRs) are located in our Galaxy and originate from neutron stars with intense (< or = 10(15)G) magnetic fields-so-called 'magnetars'. On 27 December 2004, a giant flare with a fluence exceeding 0.3 erg cm(-2) was detected from SGR 1806-20. Here we report the detection of a fading radio counterpart to this event. We began a monitoring programme from 0.2 to 250 GHz and obtained a high-resolution 21-cm radio spectrum that traces the intervening interstellar neutral hydrogen clouds. Analysis of the spectrum yields the first direct distance measurement of SGR 1806-20: the source is located at a distance greater than 6.4 kpc and we argue that it is nearer than 9.8 kpc. If correct, our distance estimate lowers the total energy of the explosion and relaxes the demands on theoretical models. The energetics and the rapid decay of the radio source are not compatible with the afterglow model that is usually invoked for gamma-ray bursts. Instead, we suggest that the rapidly decaying radio emission arises from the debris ejected during the explosion.

Journal Article↗
PubMed2005

Detection and imaging of atmospheric radio flashes from cosmic ray air showers.

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10(20) eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within approximately 50 Mpc through interactions with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.

Journal Article↗
PubMed2002

Radio-guided sentinel node detection for gastric cancer.

BACKGROUND: Radio-guided detection of sentinel nodes (SNs) has been used to predict regional metastases in patients with malignant melanoma and breast cancer. However, the validity of the SN hypothesis is still controversial for gastrointestinal cancers including gastric cancer. The aim of this study was to test the feasibility and accuracy of radio-guided mapping of SNs for gastric cancer. METHODS: Some 145 consecutive patients with gastric cancer diagnosed as T1 or T2 and evaluated clinically as N0 were enrolled. Endoscopic injection of technetium-99m-radiolabelled tin colloid was performed before operation and radioactive SNs were identified with a gamma probe. Standard radical gastrectomy with lymphadenectomy was performed in all patients and all resected nodes were evaluated by routine histopathological examination. RESULTS: Using radio-guided methods, SNs were detected in 138 (95.2 per cent) of 145 patients. The SN was positive in 22 of 24 patients with lymph node metastasis. The incidence of metastasis in the SNs (7.8 per cent) was significantly higher than that in the non-SNs (0.3 per cent) (P < 0.01). The diagnostic accuracy according to SN status was 98.6 per cent (136 of 138). CONCLUSION: Radio-guided SN mapping is an accurate diagnostic procedure for detecting lymph node metastasis in patients with early-stage gastric cancer.

Chi-Square Distribution↗
PubMed2005

[Influence of adjuvant radio-chemotherapy for rectal cancer on quality of life].

INTRODUCTION: Modern therapy for rectal cancer is associated with functional disorders. Dysfunction as a consequence of surgery has to be distinguished from disorders caused by postoperative therapy. Therefore we have compared the long-term functional results of patients who received postoperative radio-chemotherapy or no therapy in conjunction with low anterior resection of the rectum. PATIENTS AND METHOD: From 1997 to 2002, a total of 32 patients (16 males and 16 females) after low anterior rectal resection and postoperative radio-chemotherapy or surgical therapy alone was compared using standardized and validated instruments (Short-Form-36-Health-Survey, EORTC QLQ-C30, QLQ-CR 38 and ASCRS fecal incontinence questionnaire) in a matched-pair analysis (age, gender and time of surgery). Mean age was 61.8 (62.1) years and mean follow-up was 4 (3.8) years. RESULTS: Two out of the 40 examined parameters differed significantly. There were no significant differences in Short-Form-36-Health-Survey and EORTC QLQ-C30 scales between both groups. The QLQ-CR38 scale sexual enjoyment differed significantly, whereas future perspectives, sexual functioning, micturition problems, symptoms in the area of the gastrointestinal tract, weight loss, defecation problems, male and female sexual problems did not differ significantly. The scales Lifestyle, Coping/Behavior and Depression/Self-Perception of the ASCRS fecal incontinence questionnaire also did not differ significantly. The difference for embarrassment was significant. DISCUSSION: No differences in quality of life after postoperative radio-chemotherapy or no postoperative therapy in conjunction with low anterior rectal resection can be found. There are, however, tendencies that postoperative radio-chemotherapy has more adverse effects on continence and sexual function than low anterior rectal resection alone.

Antineoplastic Agents↗
PubMed1993

[Radio-opaque structures in the lumen of the maxillary sinus--value of computerized tomography in the diagnosis of maxillary aspergillosis].

11 patients with radio-opaque concrements in the sinus maxillaris underwent a preoperative computerized tomographic examination of the sinus maxillaris and the sinus concrements. 8 patients (72.7%) with the occurrence of radio-opaque concrements presented postoperative a histological and microbiological infection with aspergillus fumigatus. The CT-numbers of radio-opaque concrements in patients with aspergillus were 2802 +/- 302.4 HU (Hounsfield Unit). Concrements of patients without aspergillus infection (n = 3) had lower density (368.6 +/- 149.1 HU; p < 0.001). The root filling materials showed nearly the same CT-numbers in patients with aspergillus infection (2537 +/- 398.5 HU) and in patients without aspergillus infections (2544.3 +/- 460.6 HU). Density of root filling material was at the same level as density of radiopaque concrements in patients with aspergillus infections. According to CT-examinations a direct connection between root filling materials and aspergillus infection was noted. Therefore in patients with radio-opaque concrements computerized tomographic examination helps to determine the kind of sinus infection.

Adult↗
PubMed1999

Radio-induced structural membrane modifications: a potential bioindicator of ionizing radiation exposure?

PURPOSE: This study focused on radio-induced membrane alterations in order to assess some related parameters as potential biological indicators of ionizing radiation effects in cases of accidental overexposure. MATERIALS AND METHODS: Radio-induced membrane alterations were assessed after gamma-irradiation of human blood. Biophysical techniques based on fluorescent probe incorporation into isolated living lymphocytes and erythrocytes membranes were applied. RESULTS: Using the technique of fluorescence polarization, the lipophilic phase of the membrane was shown to be more fluid whereas the lipid-protein interface of the membrane was shown to be more rigid after gamma-irradiation. Fluorescent anisotropy modifications showed dose-time effect relationships after radiation exposure. Ionizing radiation induced a decrease in steady-state anisotropy values but did not affect the probe's lifetime as assessed by fluorescence lifetime distribution technique. These data suggest that the anisotropy variations are representative of the local properties of the fluorescent probe's micro-environment. However, the distribution width showed a decrease pointing towards radiation-induced changes of membrane domain organization, probably due not only to membrane water penetration related to lipoperoxidation, but also to compositional changes and redistribution of membrane components. In contrast, the lack of radiation effect observed using the lateral diffusion index technique may be related to the integrated overview of the radio-induced modifications of the membrane provided by this technique, which pointed out radio-induced damage to the membrane in micro-domains. CONCLUSION: These findings suggest the utility of structural membrane modification measurements as an early bio-indicator of ionizing radiation exposure.

Cell Membrane↗
PubMed2000

Discovery of an Obscured Broad-Line Region in the High-Redshift Radio Galaxy MRC 2025-218.

This Letter presents infrared spectra taken with the newly commissioned near-infrared spectrometer (NIRSPEC) on the Keck II telescope of the high-redshift radio galaxy MRC 2025-218 (z=2.63). These observations represent the deepest infrared spectra of a radio galaxy to date and have allowed for the detection of Hbeta, [O iii] lambdalambda4959, 5007, [O i] lambda6300, Halpha, [N ii] lambdalambda6548, 6583, and [S ii] lambdalambda6716, 6713. The Halpha emission is very broad (FWHM=9300 km s-1) and luminous (2.6x1044 ergs s-1), and it is very comparable to the line widths and strengths of radio-loud quasars at the same redshift. This strongly supports active galactic nucleus unification models linking radio galaxies and quasars, although we discuss some of the outstanding differences. The line [O iii] lambda5007 is extremely strong and has extended emission with large relative velocities toward the nucleus. We also derive that if the extended emission is due to star formation, each knot has a star formation rate comparable to a Lyman-break galaxy at the same redshift.

Journal Article↗
PubMed2000

Radio Galaxy Clustering at z approximately 0.3.

Radio galaxies are uniquely useful as probes of large-scale structure since their uniform identification with giant elliptical galaxies out to high redshift means that the evolution of their bias factor can be predicted. As the initial stage in a project to study large-scale structure with radio galaxies, we have performed a small redshift survey, selecting 29 radio galaxies in the range of 0.19<z<0.45 from a contiguous 40 deg(2) area of sky. We detect significant clustering within this sample. The amplitude of the two-point correlation function that we measure is consistent with no evolution from the local (z<0.1) value. This is as expected in a model in which radio galaxy hosts form at high redshift and thereafter obey a continuity equation, although the signal-to-noise ratio of the detection is too low to rule out other models. Larger surveys out to z approximately 1 should reveal the structures of superclusters at intermediate redshifts and should strongly constrain models for the evolution of large-scale structure.

Journal Article↗
PubMed2004

Radio-guided surgery improves outcome of therapeutic excision in non-palpable invasive breast cancer.

Intratumoral injection of a radiocolloid for lymphatic mapping enables the therapeutic excision of clinically occult breast cancer with the aid of a gamma-ray detection probe. The aim of this study was to determine the success rate of radio-guided tumour excision in addition to a guide wire and to identify factors predicting clear margins. Sixty-five consecutive patients underwent radio-guided tumour excision after intratumoral injection of 99mTc-nanocolloid guided by ultrasound or stereotaxis. A localization wire was inserted after scintigraphy had been performed (group 1). The results were compared with retrospective data from 67 consecutive patients who underwent therapeutic wire-directed excision alone (group 2). Factors predicting clear margins (> or = 1 mm) were determined in a logistic regression model. Adequate margins were obtained in 83% of group 1 and in 64% of group 2 (P = 0.014). The invasive component was incompletely excised in two patients in group 1 and in 14 patients in group 2. Further surgery was performed in four patients in group 1 and in 14 patients in group 2. Factors predictive of clear margins were decreasing pathological tumour diameter (P = 0.035), increasing weight of the specimen (P = 0.046), absence of microcalcifications (P = 0.004) and absence of carcinoma in situ component (P = 0.024). Radio-guided excision was an independent predictor of complete excision of the invasive component (P = 0.012). The application of radio-guided surgery combined with wire localization seems to improve the outcome of therapeutic excision of non-palpable invasive breast cancer compared with wire-directed excision alone.

Breast Neoplasms↗