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PubMed2005

Observation of radio-wave-induced red hydroxyl emission at low altitude in the ionosphere.

We report the discovery of radio-wave-induced red emission of OH Meinel rotation-vibrational bands at 629.79 nm. These are the first measurements of artificial aurora below 100 km. We believe that the 629.79-nm OH emission was due to radio-wave focusing by sporadic ionization clouds near 80-85 km altitude, thus giving a technique to visualize the low-altitude sporadic ionization and providing insight into ionospheric interactions at these low altitudes.

Journal Article↗

PubMed2006

Radio frequency ablation registration, segmentation, and fusion tool.

The radio frequency ablation segmentation tool (RFAST) is a software application developed using the National Institutes of Health's medical image processing analysis and visualization (MIPAV) API for the specific purpose of assisting physicians in the planning of radio frequency ablation (RFA) procedures. The RFAST application sequentially leads the physician through the steps necessary to register, fuse, segment, visualize, and plan the RFA treatment. Three-dimensional volume visualization of the CT dataset with segmented three dimensional (3-D) surface models enables the physician to interactively position the ablation probe to simulate burns and to semimanually simulate sphere packing in an attempt to optimize probe placement. This paper describes software systems contained in RFAST to address the needs of clinicians in planning, evaluating, and simulating RFA treatments of malignant hepatic tissue.

Algorithms↗

PubMed1997

Enhancement of tumor radio-response by irinotecan in human lung tumor xenografts.

We investigated the ability of 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin (CPT-11) to increase tumor radio-response in vivo using human lung tumor xenografts. The xenografts were treated with (1) CPT-11 (10 mg/kg) intraperitoneally on days 1, 5 and 9, (2) single dose radiation (10 Gy/leg) on day 1, or (3) a combination regimen of both treatments in which radiation was given 1 h after the first dose of CPT-11. DNA flow cytometry studies were performed to define the cell cycle changes following treatment for 1 to 12 h with 0, 0.5, 2.0 or 8.0 ng/ml SN-38, the major active metabolite of CPT-11. In both small cell lung cancer (MS-1) and small cell/large cell carcinoma (LX-1) xenografts, combination treatment resulted in significant tumor regression compared with the use of CPT-11 (P = 0.0005, 0.0053) or radiation treatment (P = 0.00221, 0.0035) alone. Neither severe body weight loss nor enhanced skin reaction was observed following the combined treatment. In flow cytometry studies, the proportion of cells in G2/M-phase, the most radio-sensitive phase, increased after 1 h exposure to the lowest dose of SN-38 (0.5 ng/ml). These findings suggest that CPT-11 is a potent radiosensitizing agent, and that its activity is related to the cell cycle. This is the first report to indicate that CPT-11 serves as a radiosensitizer in vivo.

Animals↗

PubMed1990

Determination of IgE-specificities in nasal secretions and sera of allergic subjects by crossed radio-immunoelectrophoresis.

Allergen-specific IgE antibodies have not only been demonstrated in the serum, but also in the nasal secretions of allergic patients by means of the radio-allergosorbent test (RAST). In this preliminary study we adapted the technique of crossed radio-immunoelectrophoresis (CRIE) to nasal secretions in order to obtain further insight into the specificity of locally collected antibodies. Based on RAST results we compared CRIE patterns in serum, nasal secretions in 13 out of 23 grass pollen allergic subjects and two out of three house dust mite allergic subjects. In the nasal secretions the same IgE specificities were found as in the corresponding serum of the individual subject and as in a reference serum pool. These data indicate that the same specificity of IgE antibody can be found in the serum and the target organ. From these data there is no evidence for a local mucosal immune response that differs in specificity from the serum response.

Animals↗

PubMed1992

The radio-opacity of fishbones.

Plain radiographs are often taken to localize fishbones which lodge in the pharynx. In this study a pig's neck was used to determine the radio-opacity of 14 different species of fishbones. Radiographs were taken with bones placed in up to four of the common sites of impaction and assessed on two occasions independently by two previously uninvolved ENT consultants. The visibility of the fishbones was scored. Inter and intra-observer agreement for species and site was determined. There was excellent interobserver agreement at both sessions for species (rs1 = 0.96, P < 0.0001, rs2 = 0.95, P < 0.0001) and site (rs1 = 0.98, P < 0.05, rs2 = 0.95, P congruent to 0.05). Intraobserver agreement for species of fish were similarly significant but not for site. The most opaque bones were cod, haddock, grey mullet and lemon sole. The site most often detected was the laryngopharynx and that most often missed was the tonsil. This study is clinically relevant because it is useful to know which species of fishbone are radio-opaque when clinical examination fails to reveal a foreign body and may clarify the decision to proceed to endoscopy.

Animals↗

PubMed1995

The radio-opacity of fishbones: a cadaveric study.

Lateral neck radiographs performed to localize impacted fishbones have a low sensitivity. The differing radio-opacities of the bones of various fish species may be a reason for this. A cadaver head and neck and the rib bones of 10 species of fish were used in this study. A laryngoscope was used to introduce a fishbone into the vallecula and then into the hypopharynx of the cadaver. A lateral radiograph was taken in each case. Ten control films were taken. The radiographs were independently reviewed by a consultant radiologist and otolaryngologist. The presence and position of any bone seen was noted. There was no inter-observer variation. All species of fishbone were visible. One bone was not seen by either observer. Visualization of fishbones is more dependent on position than their degree of radio-opacity. Routine radiography is recommended.

Animals↗

PubMed2004

Simultaneous radio- and chemotherapy for squamous cell carcinoma of the head and neck in daily clinical practice: 5 years experience in a University Hospital.

Several randomized studies and meta-analyses have shown that simultaneous radio- and chemotherapy prolongs survival in patients with unresectable squamous cell carcinoma of the head and neck as compared with conventional radiotherapy. We assessed the feasibility and effectiveness of simultaneous radiotherapy (35 x 2 Gy) and chemotherapy [cisplatinum 100 mg/m(2) or carboplatin (AUC 6) on days 1, 22 and 43] in daily clinical practice in a cohort of 87 patients treated at our institute between 1998 and 2002. Eighty patients completed radiotherapy according to schedule. Eighty patients received two courses of chemotherapy and 50 patients three courses. Nephrotoxity, bone marrow suppression and ototoxicity were the most frequent side-effects. Median weight loss was 8.5%. Median survival was 15 months and 44% of the patients were alive at 2 years. Patients receiving three courses of chemotherapy had a better survival than patients receiving two or less courses. Treatment with simultaneous radio- and chemotherapy for advanced head and neck cancer is a demanding, but feasible treatment in daily clinical practice. Survival seems to be comparable with the results achieved in patients selected for clinical trials.

Adult↗

PubMed1987

Radio-immunoassay of the functional activity of anti-D (Rh) preparations using a human monoclonal 125I-labelled anti-D.

The prophylactic effect of anti-D in the prevention of maternal immunization to the D antigen of the Rh system depends in the first instance on its ability to bind to fetal Rh-positive red cells. The functional activity of the injected anti-D in this respect is dependent on both the plasma concentration and functional affinity constant of the antibody, and both factors should be taken into account in assessing IgG anti-D preparations for clinical use. A radio-immunoassay utilizing 125-I-labelled human monoclonal anti-D has been developed which measures the amount of antibody bound to red cells after the addition of an aliquot of the test anti-D preparation. The assay is thus a functional test in that it measures the ability of the anti-D to react with the antigen. The functional activity of the test anti-D is compared to that of the international standard, and the concentration is then expressed in terms of microgram-equivalents, that is, its equivalence in functional terms to the stated amount of international standard. The radio-immunoassay was compared to the currently used agglutination assay, and the results were found to give good agreement in 18 out of the 21 samples assayed.

Antibodies, Monoclonal↗

PubMed1977

Urine marking and territoriality in Galago alleni (Waterhouse, 1837--Lorisoidea, Primates)--a field study by radio-telemetry.

A wild population of Galago alleni was controlled by trapping and followed by radio-tracking in the equatorial rainforest of Gaboon during three study periods of 3 months each in 1972, 73 and 75. The disposition of territories and the social organization are described, as well as their evolution through time. A new technique of radio telemetry permitted identification and localization of urine marking in wild galagos. Urine marking took place throughout the territory, with a fourfold increase in frequency in zones where there is a slight overlap with neighbouring territories (female--female or male--male). The function of urine washing (wetting of the soles of the feet with urine) is discussed in relation to five hypotheses proposed by different authors, and th data obtained in the field in Gaboon. We interpret this behaviour as a means of dispersal of urine marks (social signals) in a three-dimensional milieu where displacement by a combination of leaping and running creates numerous pathways.

Animals↗

PubMed1986

Characterization of angiotensin converting enzyme from rat tissue by radio-inhibitor binding studies.

Angiotensin converting enzyme (ACE) derived from rat lung, aorta, epididymus, brain, kidney and plasma was characterized by radio-inhibitor (125I-MK351A) binding studies. Under optimal binding conditions at equilibrium 125I-MK351A bound to ACE was displaced from ACE in a concentration related manner by unlabelled MK351A. MK351A binding site concentration for each tissue and equilibrium dissociation constant (KD) was estimated by Scatchard analysis of binding data. Binding sites/mg protein was greatest in lung and least in brain. The KD for kidney ACE was significantly higher than that of lung, aorta, epididymus or brain ACE (P less than 0.005; t-test, d.f. = 10). 125I-MK351A bound to ACE prepared from lung and kidney was displaced in a concentration dependent manner by SQ20881, SQ14225, MK422, and Ro31-3113-000. Concentration of ACE inhibitor required to displace 50% of bound 125I-MK351A (DD50) was consistently higher for kidney-derived ACE than lung-derived ACE. The differences in radio-inhibitor binding characteristics of ACE from different rat tissues suggests that the enzyme active site may not be identical in all organs.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1991

Neuropeptide Y radio-immunoassay: characterization and application.

1. A sensitive and specific neuropeptide Y (NPY) radio-immunoassay has been developed. This radio-immunoassay does not detect the NPY-related peptides pancreatic polypeptide or peptide YY. NPY extracted from rat plasma using sequential C18 sorbent and affinity chromatography co-eluted with synthetic rat NPY when applied to high pressure liquid chromatography. 2. The procedure of stabilization of platelets followed by high speed centrifugation reduced basal values of NPY by 60%, and this may be consistent with removal of platelets that release NPY. Administration of the cholinesterase inhibitor physostigmine (0.3 mg/kg), intravenously, produced a small but significant increase (39%) from basal concentrations of NPY. 3. NPY concentrations in young (2-3-month-old) Sprague-Dawley and Fisher 944 rats were similar; however, NPY concentrations were significantly increased (55%) in 2-year-old Fisher 944 rats. Similar to plasma concentrations of noradrenaline, NPY levels increase with age.

Aging↗

PubMed2004

Flavopiridol as a radio-sensitizer for esophageal cancer cell lines.

Flavopiridol is a synthetic flavone that has shown an antitumor effect against several cancers. Here, we investigated the in vitro effect of flavopiridol alone and the combined effect of low-dose flavopiridol plus radiation on esophageal squamous cell carcinoma cell lines. Esophageal squamous cell carcinoma cell lines (TE8, TE9 and KE4) were exposed to flavopiridol (0.05-400 nmol/L) for 48 h. Growth inhibition was evaluated by MTT assay, cell cycle distribution was determined by flow cytometry, and cyclin D1, Bcl-2 and Rb protein expression was detected by Western blotting. The effect of 0.05 nmol/L flavopiridol as a radio-sensitizer was determined by clonogenic assay. The IC50 was approximately 110-250 nmol/L. Exposure to 0.05 nmol/L flavopiridol for 48 h increased the G2/M population, while 300 nmol/L increased the G1 population. At a concentration of 300 nmol/L, nuclear fragmentation and chromatin condensation were observed in all three cell lines. Exposure to 300 nmol/L flavopiridol decreased the levels of cyclin D1 and Rb protein in all three cell lines and Bcl-2 protein was also decreased in TE8 and KE4 cells. Moreover, exposure to 0.05 nmol/L flavopiridol slightly decreased the levels of cyclin D1, Rb and Bcl-2 protein in KE4 cells. Flavopiridol treatment (0.05 nmol/L) enhanced the radio-sensitivity in all three cell lines. Low-dose flavopiridol augmented the response of esophageal squamous cell carcinoma cell lines to radiation. Administration of a low dose of flavopiridol could be a potent new therapeutic approach for improving the efficacy of radiotherapy against esophageal cancer.

Antineoplastic Agents↗

PubMedDate not supplied

Bilateral elbow malformation in a cat caused by radio-ulnar synostosis.

A 9-month-old neutered male cat was referred because of left forelimb lameness. Physical examination, laboratory analysis, and radiographic examination of the entire skeleton were performed. The radiographic diagnosis was bilateral radio-ulnar synostosis with secondary elbow malformation. A comparison between clinical and radiographic findings of the cat and those described in children affected by radio-ulnar synostosis is reported. Correlations and differences are discussed.

Animals↗

PubMed1979

Differential radiolabelling of lymphocyte membrane alloantigens and immunoglobulins: variation of H2O2 concentration during lactoperoxidase catalyzed cell surface radio-iodination.

The effect of H2O2 concentration on lactoperoxidase catalyzed cell surface radio-iodination and subsequent isolation of Murine splenic lymphocyte Ia, H-2K and Lyb-3 surface antigens and membrane immunoglobulins was studied. For most membrane polypeptides analyzed 0.3 mM H2O2 proved to be optimal for the recovery of radiolabelled antigens from detergent lysates of labelled cells by immunoprecipitation. Marked variations among surface antigens and membrane immunoglobulin polypeptide chains were observed for the iodination and recovery of these proteins above and below the optimal peroxide concentration. The results suggest that cell surface radio-iodination conditions should be standardized to the requirements of the particular membrane protein being studied. The differential iodination and recovery of discrete membrane components above and below optimal conditions may prove useful in the analysis of surface membrane protein structure and membrane association.

Animals↗

PubMed1978

The development of a radio-stethoscope for use in the horse at rest and during exercise.

The development of a radio-stethoscope for horses is described. The equipment consisted of a sound transducer applied to the skin adjacent to the trachea and a radio transmitter attached to the saddle. The signals emitted were detected by telemetry and recorded on a magnetic tape-recorder. The recorder incorporated a monitor earphone so that sounds could be reproduced at the time of recording. The frequency response obtainable ranged from a few Hz to 4 KHz. This technique provided an objective means of studying the respiratory sounds generated during exercise although absolute values could not be measured.

Animals↗

PubMed2004

How cyclic loading affects the migration of radio-opaque markers attached to tendon grafts using a new method: a study using roentgen stereophotogrammetric analysis (RSA).

An increase in anterior laxity following reconstruction of the anterior cruciate ligament (ACL) can result from lengthening of the graft construct in either the regions of fixation and/or the region of the graft substance between the fixations. RSA could be a useful technique to determine lengthening in these regions if a method can be devised for attaching radio-opaque markers to soft tissue grafts so that marker migration from repeated loading of the graft is limited. Therefore, the objectives of this study were 1) to develop a method for attaching radio-opaque markers to an ACL graft that limits marker migration within the graft, 2) to characterize the error of an RSA system used to study migration, and 3) to determine the maximum amount of migration and the time when it occurs during cyclic loading of ACL grafts. Tendon markers were constructed from a 0.8-mm tantalum ball and a stainless steel suture. Ten double-looped tendon grafts were passed through tibial tunnels drilled in bovine tibias and fixed with a tibial fixation device. Two tendon markers were sewn to one tendon bundle of each graft and the grafts were cyclically loaded for 225,000 cycles from 20 N to 170 N. At specified intervals, simultaneous radiographs were obtained of the tendon markers and a radiographic standard of known length. The bias and imprecision in measuring the length of the radiographic standard were 0.0 and 0.046 mm respectively. Marker migration was computed as the change in distance between the two tendon markers along the axis of the tibial tunnel. Marker migration was greatest after 225,000 cycles with a root mean square (RMS) value of less than 0.2 mm. Because the RMS value indicates the error introduced into measurements of lengthening and because this error is small, the method described for attaching markers to an ACL graft has the potential to be useful for determining lengthening of ACL graft constructs in in vivo studies in humans.

Animals↗

PubMed2005

Migration of radio-opaque markers injected into tendon grafts: a study using roentgen stereophotogrammetric analysis (RSA).

An increase in anterior laxity following reconstruction of the anterior cruciate ligament (ACL) can result from lengthening of the graft construct either at the sites of fixation and/or between the sites of fixation (i.e., graft substance). Roentgen stereophotogrammetric analysis (RSA), which requires that radio-opaque markers be attached to the graft, has been shown to be a useful technique in determining lengthening in these regions. Previous methods have been used for attaching radio-opaque markers to the graft, but they all have limitations particularly for single-loop grafts. Therefore, the objective of this study was to evaluate injecting markers directly into the substance of a tendon as a viable method for measuring lengthening of single-loop graft constructs by determining the maximum amount of migration after cyclic loading. Tantalum spheres of 0.8 mm diameter were used as tendon markers. Ten single-loop tendon grafts were passed through tibial tunnels drilled in calf tibias and fixed with a tibial fixation device. Two tendon markers were inserted in one tendon bundle of each graft and the grafts were cyclically loaded for 225,000 cycles from 20 N to 170 N. At specified intervals, simultaneous radiographs were obtained of the tendon markers. Marker migration was computed as the change in distance between the two tendon markers parallel to the axis of the tibial tunnel. Marker migration had a root mean square (RMS) value of less than 0.1 mm. Because the RMS value indicates the error introduced into measurements of lengthening and because this error is negligible, the method described for attaching markers to single-loop ACL grafts has the potential to be useful for determining lengthening of single-loop ACL graft constructs in in vivo studies in humans.

Animals↗

PubMedDate not supplied

Improvement of precision in spatial localization of radio-opaque markers using the two-film technique.

Radio-opaque markers implanted inside or placed on the skin of patients can be used to detect set-up errors and patient motion. The effects of imaging geometry accuracy for standard radiotherapy equipment on the precision of calculating the positions of radio-opaque spherical markers using two orthogonal radiographic film projections is investigated. Inaccuracies in the imaging geometry are computed from the manually digitized positions of the marker images on each film pair. Actual marker locations are calculated with a precision limited only by the variance in manual digitization by incorporating those imaging geometry inaccuracies into their computation. Results of a phantom study using a grid of markers in a plastic block indicate that submillimeter precision can be obtained for the spatial coordinates of individual markers, and that the precision is not sensitive to the small inaccuracies in imaging geometry present within the mechanical tolerances of modern radiotherapy treatment machines and simulators.

Humans↗