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PubMed1988

The existence of specific antibodies to cobalt in hard metal asthma.

Twelve workers with hard metal asthma diagnosed on the basis of peak flow diaries and positive bronchial reactions to cobalt chloride (CoCl2) were studied for sensitization by detection of specific antibodies to radioactive cobalt (57Co), cobalt-conjugated human serum albumin (Co-HSA) and cobalt-conjugated exchange resin (Co-resin). Their IgE titres ranged from 73 to 1500 IU/ml and eight were atopic individuals. Sixty serum samples from asthmatic patients with IgE titres of 14-4300 IU/ml were studied as controls in all tests. Eleven of twelve subject sera that selectively bound to 57Co after incubation with saturated ammonium sulphate (greater than 232 c.p.m., P less than 0.01) were divided into three groups: (1) six sera showing evidence of specific IgE antibodies to Co-HSA (greater than 673 c.p.m., P less than 0.01) without those to Co-resin; (2) one serum giving a positive radio-allergosorbent test (RAST) only to Co-resin (greater than 417 c.p.m., P less than 0.01), and (3) four sera that were negative for two antigenic agents (Co-HSA, Co-resin). These results suggest that the subjects had occupational asthma due to hard metal exposure from cobalt sensitivity. An immuno-allergic mechanism mediated by specific IgE antibodies to cobalt was confirmed to be responsible for the development of hard metal asthma, with the possibility of some role of the reaction without reagins.

Adult↗
PubMed1982

Whole-body retention and tissue distribution of 60Co in rats after oral administration of freshwater fish contaminated with 60Co.

The purpose of this report is to compare the whole-body retention and tissue distribution in rats of 60Co administered by gavage as inorganic 60CoCl2 or in a form incorporated into freshwater fish. Orizias latipes were placed in vessels containing 21. of tap water with radioactive cobalt. Periodically thereafter the fish were sacrificed, homogenized, and administered to rats via a stomach tube. Control groups of rats were given the radionuclide alone or together with a homogenate of nonradioactive fish. The whole-body retention and tissue distribution of the radionuclide were determined with an Armac counter. The results revealed that rats gavaged with 60Co incorporated into the fish retained much more 60Co than control rats. This trend was notable in rats given fish kept in radioactive solution for longer periods. Marked differences in tissue distribution of 60Co were also observed between rats given 60Co incorporated into fish and control rats.

Animals↗
PubMed1995

The effect of cobalt-60 irradiation on bone marrow cellularity and alveolar osteoclasts.

The purpose of this study was to investigate the mechanisms of bone resorption in the rat dentoalveolar complex occurring as a result of orthodontic appliance therapy. Utilizing whole body radioactive cobalt 60 (Co60) irradiation in combination with orthodontic tooth movement, the activation, recruitment, and life span of osteoclasts was studied. Thirty-four adult Fischer 344 rats were irradiated with 10 and 20 Gray of Co60. Twelve days after irradiation, each rat was fitted with an orthodontic appliance; the rats were sacrificed 7, 14, or 21 days after appliance placement. To serve as controls, another group of 12 rats was subjected to orthodontic treatment only. Histologic sections were prepared from decalcified maxillary alveolar process, and osteoclasts were counted. In the control group, osteoclasts were presence in the periodontal membrane for four weeks after appliance placement, and the largest number of osteoclasts was observed in the second week. The smaller total irradiation dose (10 Gray, administered in 5 daily fractions) induced a transient reduction in the bone marrow cell count of more than 90%, followed by a complete rebound. The peak osteoclst number also was increased 110%. In contrast, the higher total dose (20 Gray, administered in 10 daily fractions) resulted in a reduction of 60% in bone marrow cellularity and a decrease in the peak osteoclast number by 40%. Fluctuations in bone marrow cellularity generally corresponded to similar variations in the osteoclast number, but there was an apparent lack of correspondence between bone marrow cell and white blood cell values. The total period of osteoclastic presence in the periodontal membrane following orthodontic activation, normally four weeks in duration, was reduced by one week in the irradiated animals. These findings lead us to speculate that the mechanisms of osteoclast activation and recruitment following orthodontic appliance therapy may involve three consecutive waves of osteoclast maturation. The total duration of osteoclastic bone resorption lasts 4 weeks, but the osteoclast lie span is calculated to be 9 to 10 days (9 days x 3 waves = 27 days). If the results of this study are proved to be reproducible, a scientific basis may have been provided to support the common practice in orthodontics wherein the duration between orthodontic appointments is 4-5 weeks.

Alveolar Process↗
PubMedDate not supplied

[Radionuclides 90Sr and 137Cs in the benthos near the nuclear submarine "Komsomolets"].

We have analyzed the content of radionuclides 90Sr and 137Cs in the benthofauna and deposits near the nuclear submarine "Komsomolets." Analysis was performed on the basis of the materials of the 31st (1993) and 36th (1995) voyages of R/V "Akademik Mstislav Keldysh" in correspondence with the system of monitoring the state of the abiotic and biotic situation near the nuclear submarine "Komsomolets" (Norwegian Sea). Whereas during the 33rd voyage of this vessel (1994) the content of these elements in the benthic animals at stations located close to the submarine somewhat exceeded the background level of radioactivity (Kuznetsov et al., 1996), no such excess was found during the 31st and 36th voyages. Meanwhile, radioactive cobalt (60Co) was found in representatives of three groups of animals during the 31st voyage at two stations located near the submarine.

Animals↗
PubMed1999

55Cobalt (Co) as a PET-tracer in stroke, compared with blood flow, oxygen metabolism, blood volume and gadolinium-MRI.

Several studies have shown the feasibility of divalent cobalt (Co)-isotopes (55Co and 57Co) in imaging of neuronal damage in stroke, multiple sclerosis, cerebral tumors and traumatic brain injury. Little is known how regional Co uptake relates to other pathophysiological changes after stroke. Therefore, we compared 55Co-PET with functional parameters such as regional cerebral blood flow (rCBF) using C(15)O(2), regional oxygen metabolism (rCMRO(2)) using 15O(2), regional cerebral blood volume (rCBV) and post-gadolinium (Gd) T(1)w-MRI to assess the permeability of the blood-brain-barrier (BBB). Sixteen patients (10 female; six male) aged 43 to 84 (mean 69) years with first ever stroke, as shown by CT or MRI, were examined with 55Co-PET and C(15)O(2)-, 15O(2)- and C(15)O-PET in one single session, in a period varying from 0 to 30 days after stroke-onset. Regions of infarction on C(15)O(2)- and 15O(2)-PET (defined by rCMRO(2)<65% or rCBF<45% of the contralateral value) were subsequently superimposed on the 55Co-PET scan. Clinical status was established using the Orgogozo stroke scale, which was assessed both at day 1 and at discharge (at least 6 weeks after day 1). Accumulation of 55Co was seen in eight out of 16 patients, occurring in areas showing a diminished oxygen metabolism, was only partially related to blood flow, and was located mainly outside the extent of the infarction or luxury perfusion as seen on post-Gd T(1)w-MRI. Statistical analysis showed a negative correlation between the Orgogozo score at discharge and the uptake of radioactive cobalt.

Adult↗
PubMed1977

Evidence for amino acids in hydrolysates of compounds formed by ionizing radiations. I. Aqueous solutions of HCN, NH4CN, and NaCN.

Dilute, 02-free aqueous cyanides were exposed to multikilorad doses of a radioactive cobalt source. After the removal of unreacted cyanides and of volatile radiolytic products, the residue was hydrolyzed and the resulting material analyzed for amino acids. The results show the presence of five protein amino acids and five amino acids which do not occur in natural proteins. The amino acids of enantiomeric derivatives separated on an optically active column, appeared to consist of approximately equal amounts of D and L isomers. Radiation-chemical yields of amino acids were determined at various radiation doses. The results obtained support the previous findings that the free-radical initiated process is the source of oligomers which on hydrolysis release the amino acids.

Amino Acids↗
PubMed1980

Orbital carcinoid tumor metastatic from the colon.

Acute exophthalmos and ophthalmoplegia of the left eye developed in a 58-year-old woman convalescing from a right hemicolectomy for a carcinoid tumor of the colon. Roentgenograms of the orbit and computed tomograms showed a large posterior left orbital mass. Lateral orbitotomy and biopsy confirmed the diagnosis of metastatic carcinoid tumor. Irradiation with radioactive cobalt (60Co) resulted in early relief of the ocular symptoms. To the best of our knowledge, this is the second documented case of orbital metastatic carcinoid tumor and the first patient with orbital involvement from a primary carcinoid tumor of the colon. Orbital irradiation for metastatic orbital carcinoid tumor has not been previously reported and should be used for symptomatic relief, because long-term survival is possible in patients with metastatic carcinoid tumors.

Carcinoid Tumor↗
PubMed1981

Testicular seminoma metastatic to the orbit.

Painful exophthalmos, ophthalmoplegia, and visual loss in the right eye developed in a 28-year-old man four months after he underwent a radical orchiectomy and irradiation for a seminoma of the right testicle. Prednisone therapy failed to relieve the symptoms, and an orbital biopsy found a metastatic testicular seminoma. Orbital irradiation with radioactive cobalt reduced the exophthalmos, reversed the ophthalmoplegia, and improved his visual acuity. Previous cases of nonmetastatic exophthalmos in patients who had testicular seminoma have been reported, but, to the best of our knowledge, this is the first report of a patient who had orbital seminoma metastatic from the testis. Successful irradiation of the orbital focus can minimize ocular morbidity and may improve the prognosis.

Adult↗
PubMed1989

Dose estimation by ESR spectroscopy at a fatal radiation accident.

In Norway, 1982, a fatal radiation accident occurred at a radioactive cobalt source used for radiation processing. There was a lack of realistic estimates on the victim's tissue or body doses up to his death. GSF was able to provide the first reliable dose values, upon request from Norwegian colleagues. Dosimetry was performed by ESR spectroscopy of long-lived radiation-induced radicals that could be measured in the heart tablets of the victim. The concentration of the free radicals proved, by proper calibration, to be proportional to dose. Procedures and dose results are reported; comparison is made with data from literature dealing with the same subject and also using TL as well as ESR. For biological relevance, the doses as determined from the tablets are converted into whole-body doses.

Accidents, Occupational↗
PubMed2005

60Co aqueous speciation and pH effect on the adsorption behavior on inorganic materials.

The adsorption of radioactive cobalt from aqueous solution on MgO, MnO(2), TiO(2), SnO, activated carbon and calcined hydrotalcite was studied under static conditions as a function of pH (1, 3, 5, 7, and 10) of the (60)Co solution. It was found that under the experimental conditions, (60)Co was significantly adsorbed on MnO(2), TiO(2) and activated carbon and in smaller quantities on MgO, SnO and calcined hydrotalcite. The adsorption of (60)Co species on MgO, MnO(2), TiO(2) and SnO can be attributed to the direct exchange of ions with a specific group on the adsorbing surface, in accordance with the concept of zero point charge (zpc). The radionuclide content was determined by gamma-spectrometry. The (60)Co chemical species present in aqueous solutions with different pH values were surveyed by using high-voltage electrophoresis. It was also found that (60)Co was present only as a cationic species at pH 1, 3, 5 and 7 and a neutral species at alkaline pH.

Adsorption↗
PubMed1981

Orbital invasion by an intracranial chordoma.

A 26-year-old woman experienced bilateral hearing loss, progressive nasal obstruction, and rhinorrhea. Examination disclosed a retropharyngeal mass. A needle biopsy specimen of the mass showed that it was a chordoma. The patient underwent surgery to remove the mass and received a postoperative course of radioactive cobalt. She did well for 18 months, at which time proptosis gradually developed in her right eye. Although the optic nerve heads and visual fields appeared normal, roentgenograms showed a large lesion involving the anterior and middle cranial fossae and destruction of the right posterior ethmoid sinus and right superior orbital fissure. Shortly after completing a course of methotrexate therapy (total dose, 89 mg), the patient experienced sudden pain and visual loss in her right eye. Surgical decompression of the orbit failed to restore light perception. The following year, her left eye became involved. A transfrontal craniotomy and extradural orbital decompression provided only temporary improvement. Four months later, left lateral rectus muscle palsy developed and her visual acuity decreased to 6/60 (20/200). Radiation therapy (400 rads per week; total dose, 3,200 rads) and treatment with methotrexate, vincristine sulfate, and prednisone did not improve her condition. At the time of her death, six years after the first symptom appeared, the patient was blind in both eyes, almost completely deaf, and suffered from severe dysphagia.

Adult↗
PubMed1999

Osteoclast activation and recruitment after application of orthodontic force.

In this study, whole body radioactive cobalt 60 (Co60) irradiation was used in an orthodontic tooth movement model to investigate osteoclast activation and recruitment in adult rats. Seventy-five rats were divided into three groups and were irradiated with Co60 ranging from 10 to 26 Gray. An orthodontic appliance was fitted to each rat 12 days after initiation of irradiation. Identical appliances were fitted on an additional 25 unirradiated rats. Groups of rats were sacrificed 1 week before and on the day of appliance placement as well as 1, 2, 3, 4, or 5 weeks after appliance placement. Histologic sections from decalcified maxillary processes were prepared and osteoclasts were counted. Results showed that regardless of irradiation dosage, osteoclast number did not decrease during the first 3 weeks of orthodontic treatment; animals receiving lower (ie, 10 Gray) total irradiation actually showed a transient increase in the osteoclast number. In addition, regardless of dose in the irradiated rats, the total time osteoclasts were present in the periodontal membrane after orthodontic activation was reduced from 4 to 3 weeks. These findings lead us to hypothesize that osteoclasts involved in appliance-induced remodeling are initially from precursors in the periodontal membrane. During prolonged periods of orthodontic force application, replacement osteoclasts originate from bone marrow precursors. Although an orthodontic bone resorption cycle lasts 4 weeks, the life span of individual osteoclasts is limited to 9 to 10 days. The clinical significance of this finding remains to be elucidated.

Animals↗
PubMed1988

Electromagnetic energy and food processing.

The use of electromagnetic energy in food processing is reviewed with respect to food safety, nutritional quality, and organoleptic quality. The effects of nonionizing radiation sources such as microwave and radio-frequency energy and ionizing radiation sources, e.g. radioactive cobalt-60 and caesium-137, on the inactivation of microbes and nutrients are compared with those of conventional heating processes both in terms of their kinetic behavior and their mechanisms of interaction with foods. The kinetics of microwave and conventional thermal inactivation are considered for a generalized nth-order model based on time and temperature conditions. However, thermal inactivation effects are often modeled by 1st-order kinetics. Microbial and nutrient inactivation by ionizing sources are considered for a 1st-order model based on radiation dose. Both thermal and radiation resistance concepts are reviewed and some typical values of radiation resistance are given for sensitive vegetative bacterial cells, yeasts, and molds and for resistant bacterial spores and viruses. Nonionizing microwave energy sources are increasingly used in home and industrial food processing and are well-accepted by the American public. But, despite recent Food and Drug Administration approval of low and intermediate ionizing radiation dose levels for grains and other plants products and the fact that irradiated foods are sold in more than 20 countries of the world, public fears in the U.S. about nuclear energy may limit the role of ionizing radiation in food processing and preservation and may also limit the use of nuclear fuels as an alternate source of electrical energy.

Food Handling↗
PubMedDate not supplied

Effects of flunixin meglumine on dogs with experimental gastric dilatation-volvulus.

Gastric dilatation-volvulus (GDV) was created experimentally and maintained for 90 minutes in 16 anesthetized, mixed-breed dogs. After the GDV was corrected, normal saline solution (0.044 mL/kg intravenously [IV]) was administered to eight dogs (controls), and flunixin meglumine (2.2 mg/kg IV) was administered to eight dogs. Microspheres labeled with radioactive cobalt, scandium, tin, or niobium were injected intravenously at baseline (before GDV) and minutes 90, 100, and 270, respectively, to determine tissue blood flows. Plasma endotoxin and prostacyclin were measured at the same intervals. Electrocardiogram, mean arterial pressure, portal pressure, and cardiac output were recorded continuously. Dogs were euthanatized at minute 270 and necropsied. There was no significant difference between treatment groups for any measured variable at any time. Endotoxin levels increased significantly during GDV. Prostacyclin levels were lower in dogs treated with flunixin meglumine than in controls at minutes 210 and 270. Histopathologic findings were similar for all dogs and consistent with those associated with endotoxemia. Flunixin meglumine treatment did not alter cardiac indices or tissue blood flows significantly. However, elevation of prostacyclin was inhibited by flunixin meglumine, which suggested that continued effects of endotoxic damage might be attenuated or inhibited.

Animals↗
PubMed1982

Epithelial second malignant tumours in retinoblastoma survivors. A review and report of a case.

The first case of epidermoid carcinoma of the tongue found in a retinoblastoma survivors is described. The patient, 10-year-old girl, had been treated successfully for bilateral retinoblastoma 9 years earlier. According to the literature, second malignant epithelial tumours are, in contrast to mesenchymal tumours such as osteosarcoma, very rare in retinoblastoma survivors. Initially one eye of the patient was treated with irradiation using Stallard's disk (radioactive cobalt), but we consider that Stallard's disk was unconnected with the genesis of the carcinoma of the tongue.

Adolescent↗
PubMed1977

Scintigraphic studies of uterine and placental growth and placental migration during pregnancy.

Placental scintigraphy with 113mIn (Indium) combined with cervical marking with a shielded 57Co (Cobalt) radioactive source was used to study uterine and placental growth in human pregnancy and placental location and migration in a total of 176 patients. Uterine length measurements can be used for selecting growth retarded fetuses. There was an approximately constant ratio between placenta diameter and uterine length (0.68 +/- 0.03). When the placenta was located on the ventral uterine wall, low implantation occurred in 61%. The corresponding figure for low implantation when the placenta was located on the dorsal uterine wall was 30%. The difference was highly significant. Placental migration was studied in 20 patients. Significant migration occurred in 11 cases. The placental margin closest to the internal cervical os migrated outwards about 3 cm on average.

Female↗
PubMed2005

Gamma knife thalamotomy for movement disorders: evaluation of the thalamic lesion and clinical results.

OBJECT: The authors studied the effects of gamma knife thalamotomy (GKT) on Parkinson disease-related tremor and essential tremor before and after reloading of radioactive cobalt. METHODS: Based on experience in stereotactic thalamotomy aided by depth microrecording, the target was located at the lateral border of the thalamic ventralis intermedius nucleus (VIM). For more precise targeting, the percentage representation of the thalamic VIM in relation to the entire thalamic length is useful. The location of the target was determined on magnetic resonance (MR) imaging and computerized tomography scanning. A maximum dose of 130 Gy was delivered to the target by using a single isocenter with the 4-mm collimator. In more recent cases, a systematic follow-up examination was performed at 3, 6, 12, 18, and 24 months after GKT. Since 1993, the authors have treated 70 patients with PD. Throughout the series the same dosimetric technique has been used. The course after GKT was compared between the 25 cases with PD treated before reloading and the 35 cases treated after reloading. In the majority (80-85%) treated after reloading, tremor and rigidity were reduced around 6 months after GKT. In the cases treated before reloading this effect took approximately 1 year. The thalamic reaction on MR imaging showed the same two lesion types in both series: a restricted and a diffuse. After reloading the restricted lesion was more frequent and the lesion volume was smaller. CONCLUSIONS: The shorter delay in clinical improvement and smaller lesion size may be related to an increased radiation dose.

Aged↗