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PubMed1991

A chromosomal study of workers with long-term exposure to radio-frequency radiation.

OBJECTIVE: To examine whether an increased level of chromosome damage occurs in the stimulated lymphocytes of radio-linemen after long-term but intermittent exposure to radio-frequency radiation (RFR) during the course of their work. DESIGN AND PARTICIPANTS: Chromosome studies were performed on blood samples from 38 radio-linemen matched by age with 38 controls, all of whom were employed by Telecom Australia. The radio-linemen had all worked with RFR in the range 400 kHz-20 GHz with exposures at or below the Australian occupational limits, and the controls were members of the clerical staff who had no exposure to RFR. Two hundred metaphases from each subject were studied and chromosome damage was scored by an observer who was blind to the status of the subjects. RESULTS: The ratio of the rate of aberrant cells in the radio-linemen group to that in the control group was 1.0 (95% confidence interval, 0.8-1.3). There were no statistically significant differences in the types of aberrations that were scored. CONCLUSION: Exposure to RFR at or below the described limits did not appear to cause any increase in chromosomal damage in circulating lymphocytes.

Chromosome Aberrations↗
PubMed1999

Reaching adolescents: a role for radio.

The radio is a powerful means to reach adolescents and to address their concerns, particularly those that are not being addressed by their families or by the school curriculum. Proving this point is a radio program, "Sandhikhan" (Bengali for adolescence), which aired on national radio covering adolescent health issues, particularly reproductive health. The program's impact was the subject of a WBVHA survey among adolescent radio listeners in West Bengal. About 79% (369 individual listeners) of the respondents rated the radio program very good, with only a negligible 1% describing it as unnecessary. Only 21% of respondents listened to the program alone, with the majority listening in the company of friends, mothers, sisters, brothers, fathers, and other relatives. This suggested a wider group of listeners in addition to the program's primary target audience. Clearly, findings pointed to the effectiveness of teaching adolescent health on the air and the role that was played by WBVHA in developing healthy attitudes and habits among its young audience. The findings of the survey will provide the basis for producing educational materials on reproductive health for students as well as teachers.

Adolescent↗
PubMed2006

Youth exposure to alcohol advertising on radio--United States, June-August 2004.

In the United States, more underage youth drink alcohol than smoke tobacco or use illicit drugs. Excessive alcohol consumption leads to many adverse health and social consequences and results in approximately 4,500 deaths among underage youth each year. Recent studies have emphasized the contribution of alcohol marketing to underage drinking and have demonstrated that a substantial proportion of alcohol advertising appears in media for which the audience composition is youth-oriented (i.e., composed disproportionately of persons aged 12-20 years). To determine the proportion of radio advertisements that occurred on radio programs with audiences composed disproportionately of underage youth and the proportion of total youth exposure to alcohol advertising that occurs as a result of such advertising, researchers at the Center on Alcohol Marketing and Youth (Health Policy Institute, Georgetown University, District of Columbia) evaluated the placement of individual radio advertisements for the most advertised U.S. alcohol brands and the composition of audiences in the largest 104 markets in the United States. This report summarizes the results of that study, which indicate that alcohol advertising is common on radio programs which have disproportionately large youth audiences and that this advertising accounts for a substantial proportion of all alcohol radio advertising heard by underage youth. These results further indicate that 1) the current voluntary standards limiting alcohol marketing to youth should be enforced and ultimately strengthened, and 2) ongoing monitoring of youth exposure to alcohol advertising should continue.

Adolescent↗
PubMed2006

Midair collisions in U.S. civil aviation 2000-2004: the roles of radio communications and altitude.

BACKGROUND: Midair collisions are destructive to aircraft and often fatal to occupants, with the additional possibility of death and destruction on the ground. We sought to determine the characteristics of civil aviation mid-air collisions in U.S. airspace with focus on the altitudes at which the collisions took place and radio communications prior to the collisions. METHODS: Accident reports published by the National Transportation and Safety Board for the period 2000-2004 were analyzed using descriptive statistics. Additional information was extracted from the narrative report of each accident. RESULTS: During the 5-yr period, 48 collisions in U.S. civil aviation occurred with 78 fatalities and 7 persons severely injured. There were 46 aircraft destroyed and 37 substantially damaged. In 14 cases no radio communication was reported. In 19 cases there appeared regular radio communication with a tower or other aircraft. CONCLUSIONS: Midair collisions resulted in fewer severe injuries at lower altitudes. Visibility and weather were not contributing factors. Radio communication is recommended to assist aircraft where practical, but pilots need to be made aware of the limitations of radio communication for the avoidance of midair collisions.

Accidents, Aviation↗
PubMed1997

A review of the use of radio-isotopes in medicine and medical research in Australia (1947-73).

Recent reports in the Australian media have claimed that after the Second World War 'hundreds of (Australians) were injected with radioactive materials in medical experiments that continued in Australian hospitals until the 1960s'. These claims prompted a review of archival records of the Australian Radiation Laboratory (ARL) that are held by the Australian Archives pertaining to the medical uses of radio-isotopes during the period 1947-73. The material examined indicates that the procurement, distribution, and therapeutic and diagnostic uses of radio-isotopes were stringently controlled by the Radio-isotopes Standing committee (RSC) until 1973, when the responsibility of regulation of medical uses of radio-isotopes passed to the Therapeutic Goods Administration. On the basis of available information it appears that the claims made by the media that many Australians were subjected to unconscionable medical experiments are unjustified. A full report has been released by the Commonwealth Minister for Human Services and Health. The following is an abridged version of that report, detailing some of the more contentious uses of radio-isotopes for medical purposes in Australia during the period 1947-73.

Advisory Committees↗
PubMed1998

Evaluation "in-car" countermeasures to sleepiness: cold air and radio.

The efficacy of putative "in-car" countermeasures to driver sleepiness is unknown. Sixteen young adult drivers within the normal range for the Epworth Sleepiness Scale (ESS), had their sleep restricted to 5 hours the night before, and drove an interactive car simulator in the afternoon for 2.5 hours, under monotonous conditions. After 30 minutes of driving they were exposed to: (1) cold air to the face (AIR) from the vehicle's air conditioning vents, (2) listening to the vehicle's radio/tape (RADIO) according to subjects' choice, or (3) NIL treatment. The active treatments typified those experienced under real driving conditions. Drifting over lane markings were "incidents." EEGs were recorded and spectrally analyzed in the alpha and theta range. Subjects responded to the Karolinska Sleepiness Scale (KSS) every 200 seconds. Overall, RADIO and AIR had no significant effects on incidents, although there was a trend for RADIO to reduce incidents, particularly during the first 30 minutes, when AIR also had some effect. KSS scores were significantly lower for RADIO for most of the drive, whereas AIR had only transient and non-significant effects. The EEG showed no significant effects of the active treatments. Compared with other countermeasures such as caffeine and a brief nap, which we have previously shown to be more effective (using the same equipment and protocols), AIR and RADIO are at best only temporary expedients to reduce driver sleepiness, perhaps enabling drivers to find a suitable place to stop, take a break and avail themselves of caffeine and a nap.

Accidents, Traffic↗
PubMed1989

Influence of animal host and tumor implantation site on radio-antibody uptake in the GW-39 human colonic cancer xenograft.

The magnitude and kinetics of tumor uptake of a monoclonal antibody (MAb) directed against carcinoembryonic antigen (CEA) in the GW-39 human colorectal cancer xenograft differ according to the animal used (nude mouse or hamster) and the site of implantation of the tumor within the animal (cheek pouch, leg muscle, subcutaneous or liver). Several physiological factors have been evaluated in an attempt to explain these differences in radio-antibody accumulation. The following observations have been made: (1) The animal host with the slower blood clearance of radio-antibody and the higher non-tumor tissue uptake has the higher tumor uptake; (2) the xenografts with a higher blood-flow rate, vascular volume and/or vascular permeability have a higher specific radio-antibody targeting; (3) the smaller, more viable tumors take up more radio-antibody per gram than the larger tumors; and (4) tumors with higher specific antigen content accrete more radio-antibody. These results are discussed in terms of the feasibility of clinical tumor imaging and therapy with radiolabelled antibodies.

Animals↗
PubMed1996

Early chemotherapy and concurrent radio-chemotherapy in high grade glioma.

PURPOSE: The poor results from treatment of high grade glioma prompted us to explore new protocols involving concurrent radio-chemotherapy. Our primary objective was to evaluate the feasibility of very early postoperative chemotherapy with BCNU, concurrent radio-chemotherapy with carboplatin and teniposide, and post-radiotherapy BCNU. Our secondary objectives were to evaluate time to progression, and overall survival. PATIENTS AND METHODS: We treated 24 newly diagnosed patients (pts) with BCNU 150 mg/m2 seven days after surgery. Thirty days later, we started radiotherapy, 1.8 to 2 Gy/day for 5 days a week on limited fields up to 60 Gy, and concurrent chemotherapy with carboplatin 250 mg/m2 on days 1, 22, and 43, and teniposide 50 mg/m2 on days 1, 2, 3, 22, 23, 24, 43, 44 and 45. Two cycles of 150 mg/m2 BCNU were then given at 30 and 70 days, respectively, after the end of the radio-chemotherapy course. Therapy was then suspended, but if disease progression was evident, treatment was resumed with drugs that had not been previously employed. Surgical reintervention was not routinely considered. RESULTS: Following radio-chemotherapy treatment in the 24 pts evaluable for response, we observed partial remissions in 8 cases (33%) and stable disease in 12 (50%). Actuarial estimates of progression free survival (PFS) were 33 weeks, with 56 wks for anaplastic astrocytoma and 31 weeks for glioblastoma. Median survival time (MST) of all pts was 58 weeks; 51 weeks for glioblastoma and was not reached for anaplastic astrocytoma. This regimen was feasible. Of 144 planned cycles, 139 were delivered, and among these only in 13 and 9 cycles the doses were reduced by 75 and 50%, respectively. We did not observe any gastrointestinal toxicity. Grade 2 hematological toxicity occurred in 25% of pts. grade 3 in 4% and neurological toxicity in 3% of the pts during BCNU delivery, probably due to a sharp increase in intracranial pressure. CONCLUSION: Early chemotherapy, concurrent chemo-radiotherapy and brief post-radio-therapy chemotherapy are feasible and well tolerated. The objective response and disease stabilization rates appear similar to previous experiences.

Adult↗
PubMed1983

Role of radio-aerosol and perfusion lung imaging in early detection of chronic obstructive lung disease.

The efficacy of radio-aerosol and perfusion lung imaging in the early detection of chronic obstructive lung disease was evaluated in 38 subjects. The subjects included 5 non-smokers, 21 smokers with minimal or no respiratory symptoms and 12 patients with chronic obstructive lung disease. Each subject consented to a respiratory questionnaire, detailed physical examination, chest X-ray examinations, detailed pulmonary function tests and 99mTc-radio aerosol-inhalation lung imaging. Perfusion lung imaging with 99mTc-labelled macroaggregated albumin was performed in 22 subjects. A significant correlation (P less than 0.001) was observed between the degree of abnormalities on radio-aerosol imaging and pulmonary function tests (PFTs) including forced expiratory volume in 1 s, maximum mid-expiratory flow rate and mean transit time analysis. Abnormal radio-aerosol patterns and deranged PFTs were observed in 21 subjects each. Of 21 subjects with abnormal radioaerosol pattern 8 had normal PFTs. Of 21 subjects with abnormal PFTs 8 had normal aerosol images. Aerosol lung images and PFTs were abnormal more frequently than perfusion lung images. The results suggest that radio-aerosol lung imaging is as sensitive an indicator as PFTs for early detection of chronic obstructive lung disease and can be usefully combined with PFTs for early detection of alteration in pulmonary physiology in smokers.

Adolescent↗
PubMed2006

The range of optimal concentration and mechanisms of paclitaxel in radio-enhancement in gastrointestinal cancer cell lines.

AIM: This study was performed to investigate the range of optimal concentration and mechanisms of paclitaxel (PXL) radio-enhancement in gastrointestinal cancer cell lines HT29 and MKN45. METHODS: Cell growth inhibition by PXL pretreatment at various concentrations (0-10 microM) followed by irradiation was investigated using a modified MTT assay. To investigate the mechanisms of the observed radio-enhancement, flow cytometry was conducted to define the cell cycle distributions. Furthermore, the alterations in expression of a DNA repair molecule [excision repair cross-complementation group1 (ERCC1)] and an angiogenesis factor [vascular endothelial growth factor (VEGF)] induced by PXL were investigated. RESULTS: Cytotoxic concentrations of PXL (0.1-10 microM) that cause accumulation of cells in the G2/M phase have strong radio-enhancing effects and inhibit total cell growth. The maximal non-cytotoxic concentration of PXL (0.01 microM) also had a radio-enhancing effect. The expression of the genes of ERCC1 and VEGF induced by radiation was suppressed by PXL pretreatment. The protein secretion of VEGF induced by radiation was suppressed at cytotoxic doses of PXL, and the induced protein secretion of ERCC1 was also suppressed even at maximal non-cytotoxic doses of PXL. CONCLUSION: The range of optimal concentration for PXL pretreatment was 0.01-0.1 microM in these cells. Two major mechanisms of radio-enhancement are suggested: (1) PXL induces G2/M arrest leading to increased DNA damage after radiation, which results in mitotic death, and (2) PXL suppresses the expression of radiation-induced DNA repair molecules and angiogenesis factors, resulting in inhibition of cell growth and cell death.

Adenocarcinoma↗
PubMed2003

Laparoscopic application of radio frequency energy enables in situ renal tumor ablation and partial nephrectomy.

PURPOSE: To our knowledge we present the initial series of renal mass in situ laparoscopic radio frequency ablation. We also discuss the indications for and results of subsequent laparoscopic partial nephrectomy. MATERIALS AND METHODS: Laparoscopic radio frequency ablation was performed in 13 patients with a mean age of 59 years (range 18 to 81) and a total of 17 small enhancing renal masses. In 5 patients the tumor was subsequently excised completely, whereas in 7 it was left in situ after treatment. In 1 patient with 5 lesions only the largest lesion was excised, while the other 4 were left in situ. RESULTS: Mean tumor size was 1.96 cm. (range 0.9 to 3.6). Tumors that remained in situ tended to be endophytic and located in the mid pole. Pathological analysis revealed renal cell carcinoma in 10 patients, angiomyolipoma in 2 and oncocytoma in the patient with multiple lesions. None of the 8 patients with renal cell carcinoma who had at least 6 weeks of followup (mean 9.8 months, range 1.5 to 22) had any evidence of persistent tumor enhancement on surveillance computerized tomography or any other evidence of disease progression. There was 1 focal positive margin in a patient who underwent radio frequency ablation and excision of renal cell carcinoma but the patient remained disease-free 1 year after treatment. CONCLUSIONS: Early experience with laparoscopic radio frequency ablation in situ or combined with partial nephrectomy shows that it appears to be a safe method of managing small enhancing renal masses. Radio frequency assisted laparoscopic partial nephrectomy is reserved for easily accessible exophytic tumors, while strict surveillance is required for lesions remaining in situ after ablation. Additional followup is required to assess long-term effectiveness.

Adolescent↗
PubMed2002

Phase II trial of radio frequency ablation of renal cancer: evaluation of the kill zone.

PURPOSE: We report on the pathological evaluation of renal tumors after intraoperative radio frequency ablation performed immediately before surgical nephrectomy. MATERIALS AND METHODS: Ten patients with renal tumors were enrolled in a prospective, Institutional Review Board approved phase II trial of radio frequency ablation. Following surgical exposure of the kidney a single 12-minute radio frequency ablation of the tumor was performed using the Radionics Cool-tip RF Radio Frequency Ablation System (Radionics, Burlington, Massachusetts). The tumor was then excised via radical or partial nephrectomy. Gross and histological evaluations of the tumor were performed, including evaluation with nicotinamide adenine dinucleotide vital staining. RESULTS: All 10 tumors were confirmed histologically to be renal cell carcinoma. Mean tumor size was 3.2 cm. (range 1.4 to 8.0). Of the 10 tumors 8 were completely ablated with a mean treatment margin of 6.75 mm. (range 2 to 13). Of the 2 tumors that were incompletely treated 1 never attained a temperature sufficient for tissue destruction and the other measured 8 cm., far exceeding the expected ablation volume of treatment protocol. CONCLUSIONS: This study represents the initial report of the histological outcome of saline cooled radio frequency ablation of renal tumors. Our data indicate that it can completely destroy renal cancers while transmitting minimal collateral damage to surrounding renal parenchyma. Further investigation is required to determine long-term oncological outcome.

Adult↗
PubMed2002

Incomplete renal tumor destruction using radio frequency interstitial ablation.

PURPOSE: We evaluate the efficacy of temperature based radio frequency ablation as a potential treatment modality for small (less than 3.5 cm.) renal tumors. MATERIALS AND METHODS: We treated 15 patients with a total of 20 tumors with radio frequency ablation through an open surgical approach immediately before partial nephrectomy. All tumors were biopsied before radio frequency ablation treatment. Tumors were heated to 90 to 110C for 6 to 16 minutes (mean 9.1). Tumor ablation was monitored by direct vision and ultrasound. Partial nephrectomy was performed in standard fashion. All specimens were stained with hematoxylin and eosin, and 5 specimens were stained for nicotinamide adenine dinucleotide (NADH) diaphorase activity. RESULTS: Tumors ranged from 1.5 to 3.5 cm. (mean 2.4) in greatest dimension. All 20 specimens had evidence of morphologically unchanged tumor and normal renal parenchyma on standard hematoxylin and eosin staining. Of the 5 specimens 4 stained positively for NADH in areas confirmed to be tumor in hematoxylin and eosin stained neighboring sections. There was 1 intraoperative renal pelvic thermal injury requiring pyeloplasty and 2 postoperative caliceal leaks requiring stent placement. CONCLUSIONS: In our series radio frequency therapy did not result in total tumor destruction when specimens were examined with hematoxylin and eosin or NADH staining. We believe that radio frequency interstitial tumor ablation of renal cell carcinoma without subsequent tissue resection should continue to be an investigational treatment modality for those who would otherwise undergo partial or radical nephrectomy.

Biopsy↗
PubMed2001

Enhancement of the therapeutic outcome of radio-immunotherapy by combination with whole-body mild hyperthermia.

To enhance the effect of radio-immunotherapy for solid cancers, whole-body mild hyperthermia was added, and its effects on the pharmacokinetics of radiolabelled antibody, outcome of radio-immunotherapy, and radiosensitivity of the tumour were investigated. Nude mice bearing human colon cancer xenografts were heated to 40 degrees C for 3 or 6 h. After heating, mice received intravenous (i.v.) injections of [131I]-labelled anti-carcinoembryonic antigen (CEA) monoclonal antibody. Although 6-h heating did not alter the biodistribution of the radiolabelled antibody, and alone did not show any therapeutic effect on tumour growth, when combined with radio-immunotherapy, the therapeutic effect on tumour growth was significantly enhanced. Three-hour heating also significantly enhanced the effect of radio-immunotherapy. Colony formation assay showed that the radiosensitivity of the tumour was significantly enhanced after heating, which was achieved by a reduction of the hypoxic fraction of the tumour. In conclusion, the addition of whole-body mild hyperthermia significantly enhanced the therapeutic effect of radio-immunotherapy by increasing the radiosensitivity of the tumour.

Animals↗
PubMed2001

Non-detection at Venus of high-frequency radio signals characteristic of terrestrial lightning.

The detection of impulsive low-frequency (10 to 80 kHz) radio signals, and separate very-low-frequency (approximately 100 Hz) radio 'whistler' signals provided the first evidence for lightning in the atmosphere of Venus. Later, a small number of impulsive high-frequency (100 kHz to 5.6 MHz) radio signals, possibly due to lightning, were also detected. The existence of lightning at Venus has, however, remained controversial. Here we report the results of a search for high-frequency (0.125 to 16 MHz) radio signals during two close fly-bys of Venus by the Cassini spacecraft. Such signals are characteristic of terrestrial lightning, and are commonly heard on AM (amplitude-modulated) radios during thunderstorms. Although the instrument easily detected signals from terrestrial lightning during a later fly-by of Earth (at a global flash rate estimated to be 70 s(-1), which is consistent with the rate expected for terrestrial lightning), no similar signals were detected from Venus. If lightning exists in the venusian atmosphere, it is either extremely rare, or very different from terrestrial lightning.

Journal Article↗
PubMed2001

Discovery of radio emission from the brown dwarf LP944-20.

Brown dwarfs are not massive enough to sustain thermonuclear fusion of hydrogen at their centres, but are distinguished from gas-giant planets by their ability to burn deuterium. Brown dwarfs older than approximately 10 Myr are expected to possess short-lived magnetic fields and to emit radio and X-rays only very weakly from their coronae. An X-ray flare was recently detected on the brown dwarf LP944-20, whereas previous searches for optical activity (and one X-ray search) yielded negative results. Here we report the discovery of quiescent and flaring radio emission from LP944-20, with luminosities several orders of magnitude larger than predicted by the empirical relation between the X-ray and radio luminosities that has been found for many types of stars. Interpreting the radio data within the context of synchrotron emission, we show that LP944-20 has an unusually weak magnetic field in comparison to active M-dwarf stars, which might explain the previous null optical and X-ray results, as well as the strength of the radio emissions compared to those at X-ray wavelengths.

Journal Article↗
PubMed2006

Transient radio bursts from rotating neutron stars.

The radio sky is relatively unexplored for transient signals, although the potential of radio-transient searches is high. This was demonstrated recently by the discovery of a previously unknown type of source, varying on timescales of minutes to hours. Here we report a search for radio sources that vary on much shorter timescales. We found eleven objects characterized by single, dispersed bursts having durations between 2 and 30 ms. The average time intervals between bursts range from 4 min to 3 h with radio emission typically detectable for <1 s per day. From an analysis of the burst arrival times, we have identified periodicities in the range 0.4-7 s for ten of the eleven sources, suggesting origins in rotating neutron stars. Despite the small number of sources detected at present, their ephemeral nature implies a total Galactic population significantly exceeding that of the regularly pulsing radio pulsars. Five of the ten sources have periods >4 s, and the rate of change of the pulse period has been measured for three of them; for one source, we have inferred a high magnetic field strength of 5 x 10(13) G. This suggests that the new population is related to other classes of isolated neutron stars observed at X-ray and gamma-ray wavelengths.

Journal Article↗
PubMedDate not supplied

Sensitivity of radiographic evaluation of radio-ulnar incongruence in the dog in vitro.

OBJECTIVE: To determine the sensitivity and specificity of radiographic evaluation of radio-ulnar incongruence in canine elbow joints in vitro. STUDY DESIGN: Radiographic evaluation of induced radio-ulnar incongruence in canine cadaveric forelimbs by radiologists blinded to study design. SAMPLE POPULATION: Six cadaveric canine left forelimbs. METHODS: Extended lateral, 90 degrees flexed lateral, and cranio-caudal projections were taken of the elbow joint of six cadaveric canine forelimbs. A four-pin, type I external skeletal fixator (ESF) with a linear motor side bar was attached to the medial aspect of the radius, and a 2-cm segment of bone was removed from the mid-diaphysis. A 3.5-mm cortical bone screw placed from the medial to lateral styloid processes prevented relative movement between the distal radius and ulna during radial shortening. The ESF was used to progressively shorten the radius in increments of 0.5 mm to a total of 4 mm. The three radiographic projections were repeated after each incremental change of length. After the study, each elbow joint was disarticulated to confirm the presence of a step defect. The original radiographs and three copies were randomized and then evaluated by four radiologists blinded to the study design. Radiologists were asked to evaluate whether the joint was normal or abnormal and if there was evidence of radio-ulnar incongruence. The ability of each radiologist to correctly identify congruent elbows (specificity) and incongruent elbows (sensitivity) was calculated. RESULTS: The median specificity was 86% using the lateral projection and 82% using the cranio-caudal projection. The median sensitivities using the lateral and cranio-caudal radiographic projections were 78% and 79%, respectively. The degree of radial shortening required for individual radiologists to achieve a sensitivity of 90% ranged from 1.5 mm to greater than 4 mm. CLINICAL RELEVANCE: Standard radiographic evaluation for radio-ulnar incongruence in the dog may be associated with relatively poor sensitivity and specificity. Invasive surgical procedures and screening programs that rely on radiographic diagnosis of radio-ulnar incongruence should be discouraged until a more reliable method of diagnosis of this type of elbow joint incongruence is available.

Animals↗