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Radio emission from an ultraluminous x-ray source.

The physical nature of ultraluminous x-ray sources is uncertain. Stellar-mass black holes with beamed radiation and intermediate black holes with isotropic radiation are two plausible explanations. We discovered radio emission from an ultraluminous x-ray source in the dwarf irregular galaxy NGC 5408. The x-ray, radio, and optical fluxes as well as the x-ray spectral shape are consistent with beamed relativistic jet emission from an accreting stellar black hole. If confirmed, this would suggest that the ultraluminous x-ray sources may be stellar-mass rather than intermediate-mass black holes. However, interpretation of the source as a jet-producing intermediate-mass black hole cannot be ruled out at this time.

Journal Article↗

Giant ringlike radio structures around galaxy cluster Abell 3376.

In the current paradigm of cold dark matter cosmology, large-scale structures are assembling through hierarchical clustering of matter. In this process, an important role is played by megaparsec (Mpc)-scale cosmic shock waves, arising in gravity-driven supersonic flows of intergalactic matter onto dark matter-dominated collapsing structures such as pancakes, filaments, and clusters of galaxies. Here, we report Very Large Array telescope observations of giant ( approximately 2 Mpc by 1.6 Mpc), ring-shaped nonthermal radio-emitting structures, found at the outskirts of the rich cluster of galaxies Abell 3376. These structures may trace the elusive shock waves of cosmological large-scale matter flows, which are energetic enough to power them. These radio sources may also be the acceleration sites where magnetic shocks are possibly boosting cosmic-ray particles with energies of up to 10(18) to 10(19) electron volts.

Journal Article↗

Earth-Based Radio Tracking of the Galileo Probe for Jupiter Wind Estimation

Although the Galileo probe was designed to communicate only to the orbiter, the probe radio signal was detected at two Earth-based radio observatories where the signal was a billion times weaker. The measured signal frequency was used to derive a vertical profile of the jovian zonal wind speed. Due to the mission geometry, the Earth-based wind estimates are less sensitive to descent trajectory errors than estimates based on probe-orbiter Doppler measurements. The two estimates of wind profiles agree qualitatively; both show high wind speeds at all depths sampled.

Journal Article↗

Radio-opaque pellets as faecal markers for faecal fat estimation in malabsorption.

Thirty-seven patients undergoing routine investigation for malabsorption were given radio-opaque pellets (ROP) which were compared with polyethylene glycol and chromic oxide as continuous faecal markers. Percentage recovery of all markers showed a wide range. The recovery of all markers was very similar, and radio-opaque pellet-corrected daily faecal fat correlated very closely with PEG-and chromic oxide-corrected fat results. Estimation of ROP is precise, simple, and minimises faecal handling. ROP are suitable for routine use in faecal fat studies and have advantages over markers used at present.

Chromium↗

Tumor ablation with radio-frequency energy.

Tumor ablation by using radio-frequency energy has begun to receive increased attention as an effective minimally invasive approach for the treatment of patients with a variety of primary and secondary malignant neoplasms. To date, these techniques have been used to treat tumors located in the brain, musculoskeletal system, thyroid and parathyroid glands, pancreas, kidney, lung, and breast; however, liver tumor ablation has received the greatest attention and has been the subject of a large number of published reports. In this article, the authors review the technical developments and early laboratory results obtained with radio-frequency ablation techniques, describe some of the early clinical applications of these techniques, and conclude with a discussion of challenges and opportunities for the future.

Animals↗

Radio-contrast enhancement of a urinary tract calculus.

We report the case of a woman who presented with obstruction and urosepsis of her left kidney secondary to small cystine calculi. The calculi could not be seen on initial plain abdominal X-ray. However, following percutaneous nephrostogram the calculi became more radio-dense and visible on later X-rays. Experimental enhancement of calculi has been described before but not in man. We presume that the contrast medium was adsorbed by the calculus to increase the radio-density. Further investigation of this phenomenon could prove useful in the management of complex radiolucent calculi.

Adult↗

Role of radio-guided surgery in recurrent secondary hyperparathyroidism.

BACKGROUND: The aim of this paper is to state the role of radio-guided surgery (RGS) in case of recurrent secondary hyperparathyroidism. METHODS: Two cases of recurrent secondary hyperparathyroidism were treated using RGS. After a preoperative assessment, which included ultrasonography (US), MRI and (99m)Tc-radiolabelled sestamibi scan, a radio-guided neck re-exploration was planned. On the day of surgery the patients underwent a radionuclide injection. After 90 min, surgery began. RESULTS: Dissection was guided by placing the probe in the wound to localize any increased concentration of radioactivity. In the first case the probe identified the gland located deeply in the right tracheo-esophageal groove; in the other case the probe detected a site of increased uptake in the upper mediastinum. Both lesions were dissected and excised; a frozen section confirmed they were parathyroid glands with diffuse hyperplasia. The operative time was less than 60 min in both cases. The patients were discharged on the first postoperative day. A decrease in serum calcium and PTH was observed subsequently. A minimum follow-up of 6 months did not show any recurrence. CONCLUSION: RGS can help in detecting the parathyroid tissue in selected cases of renal hyperparathyroidism and makes operation much easier and more predictable.

Humans↗

Scintigraphy with [111In]octreotide and 201Tl in a Hürthle cell thyroid carcinoma without detectable radio-iodine uptake. Report of a case and review of the literature.

AIM: To describe the visualization of recurrent disease by [111In]octreotide and 201Tl scintigraphy in a patient with Hürthle cell thyroid carcinoma, increased thyroglobulin levels, and a negative radio-iodine total-body scan. METHODS: Scintigraphy with [111In]octreotide and 201Tl was performed, and a local recurrence in the thyroid bed was detected which was excised by surgery. RESULTS: On histology, the tumour proved to be a Hürthle cell carcinoma, and within the tumour somatostatin receptors were detected by RT-PCR. CONCLUSION: Scintigraphy with [111In]octreotide and 201Tl is an alternative imaging method for the detection of residual disease in patients with a differentiated thyroid carcinoma having increased thyroglobulin levels and a negative radio-iodine total-body scan.

Adenoma, Oxyphilic↗

Acute renal failure due to radio-contrast agents.

Over a 2-year period, acute renal failure following radio-contrast studies was observed in 25 patients after intravenous urography in 13, angiography in 10, oral cholecystography in 1, and cholangiography in 1. 20 had impaired renal function prior to the study. Renal failure, oliguric in 16 patients, occurred within 24 h. Serum creatinines reached levels of 5.3-13.3 mg% in 3-10 days. Recovery occurred in 20 patients within 5-37 days. Among the 5 patients in whom renal failure function was not restored, 1 died of progressive underlying renal disease and 4 of other causes while still in acute renal failure. These observations demonstrate the not infrequent occurrence of severe oliguric renal failure following radio-contrast study in patients with preexisting renal disease.

Acute Kidney Injury↗

Anaplastic carcinoma of the thyroid in a patient receiving radio-iodine therapy for amiodarone-induced thyrotoxicosis.

We describe a case of amiodarone-induced thyrotoxicosis following heart valve replacement in a patient with a multinodular goitre. He responded to medical therapy with carbimazole and potassium perchlorate. Subsequent therapy with radio-iodine was followed 30 weeks later by the development of anaplastic thyroid carcinoma. It is possible that amiodarone caused a low uptake of radio-iodine by the thyroid. It is not known whether this possible low dose exposure to ionising radiation played a part in the development of the anaplastic carcinoma.

Amiodarone↗

Hyperthyroidism and radio-iodine therapy in a district general hospital.

A retrospective analysis was performed of 48 patients with hyperthyroidism (41 women aged 35-80, mean 56.6 years; 7 men aged 31-77, mean 52.1 years) treated with a fixed dose of 550 MBq 131I during a 12 month period May 1991-April 1992. Weight loss was common at presentation but 28.57% of women aged 35-49 years weighed over 80 kg compared to 9.98% in a standard UK population P < 0.05. Patients treated with carbimazole (73%) prior to 131I had higher FT3 levels at presentation (14.0 +/- 4.4 pmol/l) compared to those (27%) who were considered not to require such treatment (8.9 +/- 1.4 pmol/l, P < 0.001). Four months following radio-iodine, 67% were hypothyroid, 25% were euthyroid and 8% remained thyrotoxic and were retreated. Another patient became hypothyroid during 1 year of follow-up. Pre-treatment with carbimazole did not protect against the development of hypothyroidism (carbimazole treated 69% hypothyroid at 4 months, untreated 62% hypothyroid at 4 months). Patients with continuing thyrotoxicosis had very high FT3 levels at presentation (18.6, 21.1, 20 and in one patient reported only as > 10 pmol/l). A rationalized programme of follow-up assessments at 2, 3, 4, 8 and 12 months is suggested for patients treated with this dose of radio-iodine.

Adult↗

Radio-imaging in small animals.

As the resolution of radio-imaging systems improves, the prospect of in-vivo imaging of small animals becomes more attractive. Purpose-built positron emission tomography (PET) scanners capable of imaging individual tissues within the rat brain are now in routine experimental use and in-vivo tracer and saturation-kinetic studies are now possible. The study of small animals in this way does have intrinsic problems and constraints associated with it. For example, the animal must be completely immobilized, stable ligand within the radiolabelled preparation may be limiting and anatomical definition may be poor. In spite of this, consistent, semi-quantitative data can be produced and in-vivo radio-imaging can provide a genuine and unique complement to more conventional techniques. Animal numbers can be significantly reduced and the quality of data improved due to reduced inter-animal variation, and longitudinal studies, to monitor disease progression, are feasible. As the resolution of imaging systems improves still further, such studies could be extended to mouse, in addition to rat, models of disease.

Animals↗

Radiologic examination and measurement of the wrist and distal radio-ulnar joint. New aspects.

Following fractures of the distal radius, a relatively high incidence of complications is caused by malalignment in the distal radio-ulnar (DRU) joint; recent anatomic and clinical investigations have shown congruity of that joint to be of significant importance for restoring the function of the wrist. The radius forms a moderately arched bone, which moves around the ulna in pronation and supination. Biomechanically, the ulna may be regarded as the pillar around which the radius moves. In an anatomic investigation of 5 arm specimens, we have shown that the maximum cartilage contact in the DRU joint between the ulnar head and the distal radius occurs in the neutral rotation position. A proposed routine examination method of the wrist and forearm includes a true antero-posterior and a lateral projection of the radius and the ulna, performed with the forearm and wrist in a neutral rotation, a neutral wrist deviation and with the elbow angled 90 degrees. Such an examination implies a standardized and reproducible method. In a radioanatomic investigation, a series of 50 healthy wrists and forearms were examined. A simple measuring technique is presented, applicable to the DRU joint and wrist favouring the ulna as the bone through which a reproducible long axis of the forearm/wrist may be drawn. It is suggested that the length of the radius should be judged relative to the ulna. Ulnar head inclination and radio-ulnar angle are new concepts, being major characteristics of the DRU joint. These angles of the right and left wrist were equal and no difference was found between the sexes. Minor alterations of the distal radius may be revealed when estimating these angles.

Adult↗

Value of the NBT test in the diagnosis of bacterial infection in untreated cancer patients and in those on radio- and/or chemotherapy.

As the first step in the study, the results of the NBT test in 83 patients with various untreated neoplasms, including 20 lymphomas, without bacterial infections and in 35 neoplastic patients with this complications were compared with the results obtained in control groups. No significant differences in the results were found between the groups of neoplastic patients without or with bacterial infections and the controls. To evaluate the NBT test during radio- and/or chemotherapy, especially in neutropenia, 45 patients were NBT-monitored. During the study of 102 episodes of neutropenia 43 infections occurred and 30 were NBT-confirmed. In remaining 13 cases it was impossible to perform the test because of extremely low neutrophil count (below 500/mul). All 20 infections in patients with normal neutrophil count were NBT-positive. These results confirm the usefulness of the test for infection screening in untreated with malignancies, as well as in patients receiving radio- and/or chemotherapy. However, the test can be taken only in patients without severe neutropenia.

Antineoplastic Agents↗

A pathologic study of malignant gliomas operated after radio- and chemotherapy.

Fifteen biopsies of malignant gliomas, treated before surgery by radio- and chemotherapy, have been studied. The aim of the study was to ascertain if the tissue changes, which have already been observed in autopsy samples and are related to the above mentioned treatments, occur also in biopsy samples. Even taking into due account the limitations imposed by the small number of cases, a positive correlation was found between macrophages, vessel degenerations, endothelial proliferations and radiation therapy as well as between monster cell increase and chemotherapy. These findings are consistent with those obtained with autopsy material and demonstrate that tumors after radio- and chemotherapy are more quiescent and contained.

Blood Vessels↗

Ultrasound guided brachial arterial angioplasty during the creation of a radio-cephalic arteriovenous fistula: a case report.

UNLABELLED: To prevent arteriovenous fistula (AVF) early failure, due to radial or brachial artery stenosis, ultrasound guided angioplasty performed while surgically creating the AVF could be an effective procedure. CASE REPORT: A 76-year-old diabetic male patient, on hemodialysis (HD) for 15 months, presented extensive thrombosis of the radio-cephalic AVF at the right arm, which had lasted for about 10 days. Ultrasound examination showed a 40% brachial artery stenosis with eccentric calcified plaque. The stenosis was localized about 1.5 cm before the artery bifurcation. The brachial artery diameter was 0.45 cm before and 0.26 cm at the level of the stenosis, the latter being 0.45 cm long. At the left wrist, under local anesthesia, the radial artery and the cephalic vein were exposed; the radial artery was then longitudinally incised for 7-8 mm in the area selected to create the AVF. A 6 Fr introducer, a metallic guide wire and a catheter for angioplasty were inserted one after the other in the radial artery. When the correct position of the angioplasty catheter in the stenotic area was established by ultrasound examination, the balloon was blown up to 13 atm for 35 sec, reducing the stenosis from 40-20%. Finally, a side-to-side radio-cephalic fistula was created, legating the distal vein. The AVF was used for HD after 3 weeks. The follow-up at 6 months demonstrated fair access performance and it was used without problems. Our satisfactory experience suggests that ultrasound guided angioplasty of brachial artery stenosis, performed simultaneously with surgical AVF creation, is possibly a successful procedure. This technique reduces the risk of early AVF failure and also allows, when required, stent implantation.

Aged↗

Monoclonal anti-epidermal growth factor receptor (ior EGF/r3) antibody pharmacokinetic studies on nude mice I: a radio-receptor analysis applied to drug serum quantification.

Due to its antagonistic properties upon ligand-epidermal growth factor receptor (EGFr) interaction, the monoclonal antibody anti-EGFr ior EGF/r3 is considered a potential therapeutic agent against several epithelium-derived tumours. This paper affords further analysis of the relevant corporal interaction of this monoclonal antibody in terms of its pharmacodynamic properties, using nude mice, following a single bolus intravenous dose administration. The radio-receptor assay allows quantification of the serum ior EGF/r3 level. The dose selection procedure, according to the Kolmogorov-Smirnov test, suggested using doses of 12.5-16 mg kg(-1) for pharmacokinetic assessments. The experimental data were best fitted to a bi-exponential function (r2 = 0.985), through the classical two-compartment open modelling approach. The model selection was corroborated by the AKAIKE information criteria, and also the SCHWARTZ and ESTRIP test were used. The estimated pharmacokinetic parameters (e.g. t 1/2 beta = 34.65 h, Vc = 2.84 mL, Vss = 4.21 mL and CL = 0.09 mL h(-1)) bear out the strategies for the evaluation of the therapeutic application of this drug. Finally, the radio-receptor analysis has provided a rationale for the proposed serum monoclonal antibody ior EGF/r3 quantification to characterize its concentration-time course.

Animals↗

Time accuracy of a radio frequency identification patient tracking system for recording operating room timestamps.

A patient tracking system is a promising tool for managing patient flow and improving efficiency in the operating room. Wireless location systems, using infrared or radio frequency transmitters, can automatically timestamp key events, thereby decreasing the need for manual data input. In this study, we measured the accuracy and precision of automatically documented timestamps compared with manual recording. Each patient scheduled for urgent surgery was given an active radio frequency/infrared transmitter. The prototype software tracked the patient throughout the perioperative process, automatically documenting the timestamps. Both automatic and traditional data entry were compared with the reference data. The absolute value of median error was 64% smaller (P < 0.01), and the average quartile deviation of error was 69% smaller in automatic documentation. The average delay between an activity and the documentation was 80 seconds in automatic documentation and 735 seconds in manual documentation. Both the accuracy and the precision were better in automatic documentation and the data were immediately available. Automatic documentation with the Indoor Positioning System can help in managing patient flow and in increasing transparency with faster availability and better accuracy of data.

Anesthesia Department, Hospital↗