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PubMed1997

Monitoring of the biodistribution and biokinetics of dysprosium-165 ferric hydroxide with a shadow-shield whole-body counter.

Radiation synovectomy is indicated when conventional pharmacological treatment of chronic synovitis has proved insufficient. In these cases dysprosium-165 ferric hydroxide (DFH) has been demonstrated to be clinically effective. After application of the agent, blood activity measurements and monitoring of activity distribution by gamma camera imaging over the local lymph nodes and the liver are commonly performed for control of possible leakage. In addition, we have used a shadow-shield whole-body counter with a profile facility to evaluate the biokinetics and biodistribution of 165Dy-DFH. Fifteen intra-articular injections were performed in 13 patients who received a median activity of 6.8 GBq (range 0.5-9.9 GBq) 165Dy-DFH. Activity profiles were obtained with the whole-body counter 2, 4 and 6 h after injection of 165Dy-DFH. The doses to non-target organs were calculated using the software MIRDOSE 3. In 10 of 15 treatments, absence of any leakage could be demonstrated. The effect of scattered rays could be observed in 14 measurements. In three patients small amounts of activity could be detected in the urinary bladder and in three patients activity was detected in the local inguinal lymph nodes, while no leakage could be detected by camera imaging. In these cases the individual doses to the bladder were 15 Gy, 65 mGy and 50 mGy, and those to the lymph nodes, 0.54 Gy, 0.89 Gy and 2.41 Gy. The whole-body counter also enabled the monitoring of activity profiles related to more complex pathological structures. In conclusion, using a whole-body counter activity leakage could be detected with much higher sensitivity than by using a gamma camera. The biodistribution of 165Dy-DFH could be determined, and leakage could be localised and related to organs. These results encourage the use of a whole-body counter to identify the site and extent of activity leakage.

Adult↗
PubMed1996

Radiation dosage from use of the image intensifier in orthopaedic surgery.

The image intensifier is now commonly used in orthopaedic surgery for intraoperative assessment of fracture reduction and implant placement, especially with the increasing trend toward use of closed nailing devices. We conducted a study using lithium fluoride chips to measure the radiation dosage to the surgeon and the operating theatre personnel. Over a 6-month period we measured the cumulative radiation dosage over the eyes (0.83mSv), thyroid (with shield 0.51mSv, without 0.79mSv), waist (with apron 0.48mSv, without 0.86mSv), hands (right 0.7mSv, left 0.14mSv) and feet (0.62 mSv). These values were well within the ICRP safety guidelines. The use of protective lead shielding was effective in reducing radiation dosage to operators. A survey of the operating theatre area using a radiation counter showed that radiation scatter to OT personnel was low. This study hopes to allay the fears that use of the image intensifier is hazardous to OT personnel.

Fluorides↗
PubMed1989

A multi-element proportional counter for radiation protection measurements.

A detector incorporating about 300 individual counting volumes is described, and the results of performance tests are reported. The device can be employed for a direct measurement of the dose equivalent in an unspecified radiation field on the basis of the lineal energy spectrum in 1-micron diameter tissue regions. It is substantially smaller than a conventional tissue equivalent proportional counter yielding the same counting rate and may be useful for measurements in phantoms.

Radiometry↗
PubMed2006

Use of a centrifuge-based automated blood cell counter for radiation dose assessment.

Hematological changes create early-response biomarkers for assessing radiation doses. Existing dose-prediction models are based on serial blood lymphocyte counts after acute whole-body exposure to gamma-radiation. Measurements of lymphocyte-depletion kinetics after possible exposures are useful for triaging patients and managing medical resources. The small-footprint QBC Autoread Plus System provides cost-effective hematological analyses with reproducibility, accuracy, and a broad dynamic range. QBC analysis measures centrifugally packed, whole blood cells in microhematocrit tubes and reports pooled lymphocyte and monocyte counts. Our objective was to modify this procedure to report pure lymphocyte counts for radiation biodosimetry applications. The CD14 antigen is strongly expressed on most human monocytes. Using anti-CD14-coated Dynabeads, we have devised a rapid method for depleting monocytes from whole blood without altering the lymphocyte viability or count. This simple dry procedure provides reliable lymphocyte counts for results that fall within the normal lymphocyte count range (1-4 x 10(9) cells per L) for radiation exposure assessment using lymphocyte-depletion kinetics.

Autoanalysis↗
PubMed2003

Impact of the environment on the mammalian corneal epithelium.

PURPOSE: To evaluate whether the content of ascorbic acid in the corneal epithelium and aqueous humor reflects seasonal fluctuations in parallel with environmental changes. METHODS: Reindeer, cattle, rabbits, and humans were examined, to cover a broad spectrum of overlapping habitats. Ascorbic acid was determined by high-performance liquid chromatography. The thickness of the corneal epithelium was measured, and the number of cells was counted in the tissue sections. RESULTS: Three groups of reindeer eyes were used, two of them collected during summer, the third group during winter. Ascorbate content did not show seasonal variation in either the corneal epithelium or the aqueous humor, whereas epithelial thickness and number of cells decreased significantly from summer to winter. In cattle, ascorbate content, thickness of the epithelium, and number of cells were lower in animals tended indoors compared with those tended outdoors, whereas ascorbate level in the aqueous humor remained similar in both cases. The rabbit showed significantly reduced ascorbate content in the corneal epithelium but not in the aqueous humor in tarsorrhaphy-treated eyes. This procedure did not change epithelial thickness, but the number of cells was slightly increased. The mean epithelial thickness in human corneas successively decreased with increasing latitude and decreasing radiation exposure from the summer season in Oslo to the midnight sun, polar night, conditions in Tromsø, 10 degrees far north, although the differences did not reach statistical significance. CONCLUSIONS: Ambient radiation is needed to sustain high ascorbic acid concentration in the corneal epithelium. Corneal epithelial thickness and number of cells are prone to seasonal fluctuations regulated by ambient radiation. In contrast, ascorbate content of the aqueous humor is uninfluenced by environmental change. It is suggested that seasonal adaptation of mammalian corneal epithelium in response to variation in ambient radiation may be nature's strategy for countering radiation damage to the eye.

Adult↗
PubMed1984

Nuclear reactor accidents--the use of KI as a blocking agent against radioiodine uptake in the thyroid--a review.

This paper is intended for those people who are responsible for the public health and safety in the event of a nuclear reactor accident. The possibilities and consequences of a radioiodine release are examined briefly. The possible side effects of stable iodine, the prognosis for radiation-induced thyroid disease, and the alternative protective measures are put into perspective and assessed for their individual risks and benefits. It is recommended that all appropriate counter-radiation measures be considered in the case of a reactor accident, and that the harmful side effects of the various actions be weighed carefully. Definitive guidelines as to when the use of KI is justified must be decided upon before implementing mass distribution.

Accidents↗
PubMed2002

Protective effect of RH-3 with special reference to radiation induced micronuclei in mouse bone marrow.

Effect of pre-irradiation administration of different doses of RH-3, the herbal preparation of an Indian medicinal plant Hippophae rhamnoides, 30 min before 10 Gy whole body gamma irradiation was studied. Doses between 25 to 35 mg/kg body wt. were found to render > 80 % survival in mice. In order to investigate whether RH-3 protected against radiation induced genotoxicity, mice were administered different doses of RH-3, 30 min before 2 Gy dose and compared with untreated, RH-3 treated and irradiated controls. The bone marrow cells were collected at different time intervals following various treatments and processed for scoring micronuclei (MN). Administration of RH-3 alone did not enhance the MN frequency as compared to the control, and radiation dose of 2 Gy significantly enhanced the MN frequency (3.1 %, P < 0.01). Pre-irradiation treatment with RH-3, however, reduced the radiation induced MN frequency in a drug dose dependent manner suggesting its radioprotective efficacy. The protective effect of RH-3 on radiation induced perturbations in cell cycle progression was studied flowcytometrically in mouse bone marrow cells. RH-3 treatment (30 mg/kg body wt.) enhanced DNA synthesis (S-phase) in unirradiated controls and also countered radiation induced depression of S-phase to facilitate replenishment of cells lost due to radiation injury.

Animals↗
PubMed1992

Whole-body cesium 137 activity up to 4 years after the Chernobyl reactor accident in premature newborns, newborns, infants, and children.

Cesium 137 activity was measured after the Chernobyl incident in a whole-body radiation counter (4-pi-scintillation counter) in 85 premature and mature newborns (group 1), 174 infants and young children up to 2 11/12 years (group 2), and 48 children between 3 and 8 years (group 3) from Bonn (Germany) and surroundings. In 1987 the mean level of radioactivity in group 2, at 3.7 Bq/kg body weight corresponding to a mean radiation exposure of 11 muSv/y, was lower than that of group 1 (5.8 Bq/kg, 17 muSv/y) and 3 (9.4 Bq/kg, 28 muSv/y). Up to 1990 the values of all groups revealed a continuous decrease. The latest measurements showed mean values of 0.5 Bq/kg (1.5 muSv/y) in group 1, 0.6 Bq/kg (1.8 muSv/y) in group 2, and 0.8 Bq/kg (2.4 muSv/y) in group 3. A comparison with present cesium 137 values and determinations of the end of the 1950s and beginning of 1960s, both in adults, showed good agreement. The effective dose-equivalent rates amounted to less than 1% of that from natural radiation exposure. These levels should present no teratogenic risks to the population studied and, while there are theoretical mutagenic risks, the dose is so low that no increase in measurable mutagenic effects should be observed.

Accidents↗
PubMed1978

A new method for the rapid measurement of body composition in critically ill surgical patients.

A rapid, non-invasive method for the measurement of absolute amounts of fat, protein, minerals and water in the body has been developed which is applicable to very ill patients. The patient is weighed and skinfold thickness is measured with calipers. The body contents of potassium, nitrogen, sodium, chlorine, calcium and phosphorus are measured in a whole-body radiation counter after irradiation with fast neutrons. From these values absolute amounts of body fat, protein, minerals and water are calculated. The procedure, which takes about 40 min, is carried out with the patient lying supine on a couch. The errors in the absolute measurement of the components expressed as percentages of body weight are: for fat, 4.5 per cent; for protein, 1.6 per cent; for minerals, 0.8 per cent; and for water, 4.9 per cent. The radiation dose is equivalent to that of a chest radiograph (50 mrem). We have used this technique (a) to determine the tissue composition of the weight lost in 16 patients after excision of the rectum; (b) to establish that the weight gained by 16 patients receiving intravenous nutrition was mainly water; and (c) to show that in 10 patients who received a simple solution of amino acids for 2 weeks after rectal excision body protein was preserved as efficiently as in 10 similar patients who received a full course of intravenous nutrition. This is the first time body weights of living persons have been broken down into terms of fat, protein, minerals and water, and the method should help to solve a number of metabolic and nutritional problems in clinical surgery.

Adipose Tissue↗
PubMed2006

Radioprotective properties of apple polyphenols: an in vitro study.

Present study was undertaken to evaluate the radioprotective ability of total polyphenols extracted from edible portion (epicarp and mesocarp) of apple. Prior administration of apple polyphenols to murine thymocytes significantly countered radiation induced DNA damage (evaluated by alkaline halo assay) and cell death (trypan blue exclusion method) in a dose dependent manner maximally at a concentration of 2 and 0.2 mg/ml respectively. Apple polyphenols in a dose dependent fashion inhibited both radiation or Fenton reaction mediated 2-deoxyribose (2-DR) degradation indicating its ability to scavenge hydroxyl radicals and this activity was found to be unaltered in presence of simulated gastric juice. Similarly apple polyphenols in a dose dependent fashion scavenged DPPH radicals (maximum 69% at 1 mg/ml), superoxide anions (maximum 88% at 2 mg/ml), reduced Fe(3 +) to Fe(2 +) (maximum at 1 mg/ml) and inhibited Fenton reaction mediated lipid peroxidation (maximum 66% at 1.5 mg/ml) further establishing its antioxidative properties. Studies carried out with plasmid DNA revealed the ability of apple polyphenols to inhibit radiation induced single as well as double strand breaks. The results clearly indicate that apple polyphenols have significant potential to protect cellular system from radiation induced damage and ability to scavenge free radicals might be playing an important role in its radioprotective manifestation.

Animals↗
PubMed1987

Electrical pacing of the Roux limb resolves delayed gastric emptying.

This study compares antegrade gastric and Roux-limb electrical pacing in the evaluation and treatment of delayed gastric emptying following vagotomy, antrectomy and Roux-Y enterostomy. Twenty-four male Sprague-Dawley rats (250 g) underwent midline laparotomy, truncal vagotomy, antrectomy, and Roux-Y jejunostomy. Pacemaker leads were implanted 1 cm apart in both the gastric fundus and proximal Roux limb. Pacing was accomplished using a 0.5 mA, 50 msec, 0.33 Hz signal and monitored by an oscilloscope. Animals were fasted for 2 hr and then gavaged with 1.0 cc of 99mTc-labeled egg white. At 1 hr rats were anesthetized. The stomach, Roux limb, small intestine, and colon were doubly ligated and excised without disturbing their contents. The total number of counts per minute per rat was determined in a gamma radiation counter, and percentage gastric emptying (GE) was evaluated. Group I controls (n = 8) retained 76 +/- 15.8% for a GE of 24%. Group II gastric paced rats (n = 8) retained 64.5 +/- 19.2% (GE 35.5%) and Group III Roux-limb paced rats (n = 8) retained 46.8% +/- 13.2 (GE 53.2%) (P less than 0.005 III vs I, P less than 0.05 III vs II). The amount of radioactive meal distal to the Roux limb was also evaluated. Group I had 15.7 +/- 16.1%, Group II (gastric paced) 20.5 +/- 19.0%, and Group III (Roux-limb paced) 37.2 +/- 11.9% (P less than 0.005 III vs I, P less than 0.05 III vs II). These data imply that Roux-en-Y limb dysmotility may contribute to delayed gastric emptying following vagotomy, antrectomy, and Roux-Y enterostomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1999

Comparison of antigen contents in co-cultures by an in situ immunoradiometric assay.

A fast, sensitive and reproducible in situ immunoradiometric assay has been developed to compare relative contents of cellular markers in cultures. This assay is performed directly in the multi-well plate. After methanol fixation, antigens are identified by specific primary antibodies, followed by 125I-protein A. Cell-associated radioactivity is then measured in lysates using a gamma radiation counter and expressed with respect to protein content. By this method, differences in the level of any antigen retained by fixation can be easily quantified. The convenience, dynamic range of linearity and reproducibility of this technique compare favorably with Western blotting. Originally, the assay was designed to monitor the relative abundance of glial or neuronal cells in embryonic cerebral co-cultures upon various experimental conditions, by measuring related changes in glial fibrillary acidic protein (GFAP) or microtubule-associated protein 2 (MAP-2) content. It is proposed as a method of choice to quantify the effects of culture conditions or toxic agents on a specific cell type in mixed populations.

Animals↗
PubMed2004

Shear-stress preconditioning and tissue-engineering-based paradigms for generating arterial substitutes.

In situ tissue engineering using shear-stress preconditioning and adhesive biomolecules is a new approach to autologous tissue engineering. In the present study, novel tissue-engineering grafts (TEGs) were preconditioned within an in vitro pulsatile flow circuit, with and without the addition of fibronectin (FN), to establish whether low-shear-stress conditions promoted endothelial cell (EC) retention and differentiation. TEGs ( n =24) were generated by the contraction and compaction of collagen(I) by porcine aortic smooth-muscle cells (SMCs) on to a compliant polyester graft scaffold. ECs were radiolabelled with [(111)In]indium tropolonate and seeded on to the luminal surface of the TEGs. Following organ culture in a bioreactor (7 days), TEGs were split into four groups ( n =six TEGs per group): Group A acted as controls with TEGs unmodified and seeded with radiolabelled ECs; Group B underwent luminal pre-coating with FN (75 microg/ml) prior to EC seeding; Group C underwent preconditioning within a pulsatile flow circuit at 10-20 microN (1-2 dyn)/cm(2) for 7 days prior to EC seeding, and Group D TEGs were preconditioned for 7 days at 1-2 dyn/cm(2), followed by luminal pre-coating with FN prior to EC seeding. The resistance to physiological shear stress of the seeded ECs was assessed using a gamma-radiation counter within a physiological flow circuit producing an arterial waveform with a mean shear stress of 93.2 microN (9.32 dyn)/cm(2). Environmental scanning electron microscopy (ESEM) was used to determine the distribution and degree of differentiation of the attached Ecs, and tissue-type-plasminogen-activator (tPA) assays provided a measure of function and viability. EC resistance to shear stress at 93.2 microN/cm(2) was significantly enhanced by a period of preconditioning (Group C) at 10-20 microN/cm(2), surface modification with FN (Group B), or both (Group D) when compared with control grafts (Group A). However, TEGs coated with FN whether preconditioned (Group D) or not (Group B) demonstrated the best results for EC retention. ESEM demonstrated near-confluent differentiated flattened ECs in both these cases. EC function was demonstrated by a steady increase in tPA production. Low-shear-stress preconditioning of TEGs enhances EC retention in vitro with an additional advantage demonstrated by pre-treatment with FN prior to endothelialization. These findings may be exploited in the development of tissue-engineered constructs to maintain a confluent endothelial lining.

Adaptation, Physiological↗