9.4 T static magnetic field ameliorates imatinib mesylate-induced toxicity and depression in mice.

PURPOSE: 9.4 T magnetic resonance imaging (MRI) has been initially tested on healthy human volunteers, but its future application will benefit more from experiments with animal disease models. In the meantime, high static magnetic fields (SMFs) have been shown to improve mice mental health and have anti-tumor potentials. METHODS: We compared the anti-tumor effects of 9.4 T SMF with or without a commonly used chemotherapy drug imatinib mesylate on BALB/c (Nu/Nu) mice bearing gastrointestinal stromal tumor GIST-T1 cells. The body weight, food/water consumption, complete blood count, blood biochemistry, tumor weight, HE and Ki67 stains were examined. Locomotor activity and cognitive functions were also measured by four behavior tests, including open field, elevated plus maze, three-chamber and tail suspension tests. RESULTS: We found that the tumor growth was inhibited up to 62.88% when treated with 9.4 T SMF alone for 200 h. More importantly, 9.4 T SMF combined with 20 mg/kg imatinib mesylate can result in 92.75% tumor suppression, which is close to the anti-tumor effect of high dose (80 mg/kg) imatinib. However, 80 mg/kg imatinib caused severe side effects, including significantly reduced gain of body weight, abnormal liver function and depressive behaviors in mice. In contrast, 9.4 T SMF treatment significantly reduced these side effects, especially for the depressive behaviors. CONCLUSION: Our results demonstrate that 9.4 T SMF not only has anti-tumor effects on its own, but also could improve the anti-tumor effect of imatinib mesylate, reduce its toxicity and improve the mice mental health, which unraveled the great clinical potentials of high SMF in future applications.

The Anti-Depressive Effects of Ultra-High Static Magnetic Field.

BACKGROUND: Ultra-high field magnetic resonance imaging (MRI) has obvious advantages in acquiring high-resolution images. 7 T MRI has been clinically approved and 21.1 T MRI has also been tested on rodents. PURPOSE: To examine the effects of ultra-high field on mice behavior and neuron activity. STUDY TYPE: Prospective, animal model. ANIMAL MODEL: Ninety-eight healthy C57BL/6 mice and 18 depression model mice. FIELD STRENGTH: 11.1-33.0 T SMF (static magnetic field) for 1 hour and 7 T for 8 hours. Gradients were not on and no imaging sequence was used. ASSESSMENT: Open field test, elevated plus maze, three-chambered social test, Morris water maze, tail suspension test, sucrose preference test, blood routine, biochemistry examinations, enzyme-linked immunosorbent assay, immunofluorescent assay. STATISTICAL TESTS: The normality of the data was assessed by Shapiro-Wilk test, followed by Student's t test or the Mann-Whitney U test for statistical significance. The statistical cut-off line is P < 0.05. RESULTS: Compared to the sham group, healthy C57/6 mice spent more time in the center area (35.12 ± 4.034, increased by 47.19%) in open field test and improved novel index (0.6201 ± 0.02522, increased by 16.76%) in three-chambered social test a few weeks after 1 hour 11.1-33.0 T SMF exposure. 7 T SMF exposure for 8 hours alleviated the depression state of depression mice, including less immobile time in tail suspension test (58.32% reduction) and higher sucrose preference (increased by 8.80%). Brain tissue analysis shows that 11.1-33.0 T and 7 T SMFs can increase oxytocin by 164.65% and 36.03%, respectively. Moreover, the c-Fos level in hippocampus region was increased by 14.79%. DATA CONCLUSION: 11.1-33.0 T SMFs exposure for 1 hour or 7 T SMF exposure for 8 hours did not have detrimental effects on healthy or depressed mice. Instead, these ultra-high field SMFs have anti-depressive potentials. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 1.

Safety evaluation of mice exposed to 7.0-33.0 T high-static magnetic fields.

Magnetic resonance imaging (MRI) of 7 T and higher can provide superior image resolution and capability. Clinical tests have been performed in 9.4 T MRI, and 21.1 T small-bore-size MRI has also been tested in rodents. Although the safety issue is a prerequisite for their future medical application, there are very few relevant studies for the safety of static magnetic fields (SMFs) of ≧20 T. The aim of this study was to assess the biological effects of 7.0-33.0 T SMFs in healthy adult mice. This was a prospective study, in which 104 healthy adult C57BL/6 mice were divided into control, sham control, and 7.0-33.0 T SMF-exposed groups.The sham control group and SMF group were handled identically, except for the electric current for producing SMF. A separate control group was placed outside the magnet and their data were used as normal range. After 1 h exposure, all mice were routinely fed for another 2 months while their body weight and food/water consumption were monitored. After 2 months, their complete blood count, blood biochemistry, key organ weight, and histomorphology were examined. All data are normally distributed. Differences between the sham and SMF-exposed groups were evaluated by unpaired t test. Most indicators did not show statistically significant changes or were still within the normal ranges, with only a few exceptions. For example, mono % in Group 2 (11.1 T) is 6.03 ± 1.43% while the normal range is 6.60-9.90% (p < 0.05). The cholesterol level in 33 T group is 3.38 ± 0.36 mmol/L while the normal range is 2.48-3.29 mmol/L (p < 0.05). The high-density lipoprotein cholesterol level in 33 T group is 2.54 ± 0.29 mmol/L while the normal reference range is 1.89-2.43 mmol/L (p < 0.01). Exposure to 7.0-33.0 T for 1 h did not have detrimental effects on normal adult mice. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 1.

The Analgesic Effects of Static Magnetic Fields.

Pain is one of the most common reasons why people seek medical care, which is related to most disease states. Magnetic fields (MFs) can be applied locally to specific parts of human bodies with high penetration and temporal control, which have a long-debated history in folk therapy. The purpose of this review is to collect and analyze experimental data about the analgesic effects of static magnetic fields (SMFs) so that we can have a scientific understanding regarding this topic. We collected 28 studies (25 English and 3 Chinese papers) with proper sham controls that investigated the effects of SMFs on pain relief in humans or mice. We found that 64% of the human studies and all mice studies in the literature showed positive analgesic effects of SMFs, which are related to factors including SMF intensity, treatment time, and pain types. Higher intensity and/or longer treatment time, as well as some specific pain types, may have better pain relief effects. Initial mechanistic studies indicated that membrane receptors, such as capsaicin receptor VR1/TRPV1, opioid receptors, and P2X3 receptors, might be involved. By describing experimental evidence and analysis, we found that SMFs actually hold considerable promise for managing some specific types of pain if proper SMF parameters are used. More studies comprehensively evaluating the parameters of SMF and its corresponding analgesic effects on different pain types, as well as the underlying molecular mechanisms, will be necessary to further validate its therapeutic potential in pain management in the future. Bioelectromagnetics. 00:00-00, 2021. © 2021 Bioelectromagnetics Society.

Circ_0000144 facilitates the progression of thyroid cancer via the miR-217/AKT3 pathway.

BACKGROUND: Thyroid carcinoma (TC) is the most common malignancy of the endocrine system. Circular RNA (circRNA) is vital in the regulation of tumor progression. Circ_0000144 serves as a novel oncogenic circRNA, and miR-217 is reported to inhibit the malignant phenotypes of cancer cells by targeting AKT3 in TC. The present study aimed to explore the regulatory mechanism of circ_0000144 and miR-217 in the progression of TC. METHODS: Circ_0000144 expression in 32 pairs of TC tissues and different TC cell lines (including BCPAP, K1, H7H83, and TPC-1) was detected by employing a quantitative real-time polymerase chain reaction (qRT-PCR). Circ_0000144 small interfering RNA was used to establish loss-of-function models. Cell counting kit-8 (CCK-8), BrdU (5-bromo-2'-deoxyuridine) and transwell assays were utilized to verify the effects of circ_0000144 on TC cell proliferation, migration and invasion, respectively. Bioinformatics, western blotting, a luciferase reporter experiment and qRT-PCR were employed to confirm the relationships among circ_0000144, miR-217 and AKT3. RESULTS: Circ_0000144 expression was remarkably elevated in TC tissues (p < 0.001) and TC cell lines. The elevation of circ_0000144 expression was markedly linked to tumor size (p = 0.015), TNM stage (p = 0.025) and lymph node metastasis (p = 0.017) of the patients. Functional studies showed that knocking down circ_0000144 repressed the malignancy of TC cells. Furthermore, miR-217 was identified as a downstream target of circ_0000144; inhibition of miR-217 could reverse the effects induced by circ_0000144 knockdown. Moreover, circ_0000144 could regulate AKT3 expression by suppressing miR-217 expression. CONCLUSIONS: Circ_0000144 exerts a cancer-promoting effect on TC cells via the miR-217/AKT3 pathway.

[A Treatment Plan Dose Interpolation Algorithm Based on Gradient Feature in Intensity-modulated Radiation Therapy].

The dose data produced by treatment plan system(TPS)in intensity-modulated radiation therapy(IMRT)has many gradient edge points.Considering this feature we proposed a new interpolation algorithm called treatment plan dose interpolation algorithm based on gradient feature in intensity-modulated radiation therapy(TDAGI),which improves the Canny algorithm to detect the gradient edge points and non-edge points by using the gradient information in the dose data plane.For each gradient edge point,the corresponding gradient profile was traced and the profile's sharpness was calculated,and for each non-edge point,the dispersion was calculated.With the sharpness or dispersion,the kernel coefficients of bi-cubic interpolation can be obtained and can be used as the central point to complete the bi-cubic interpolation calculation.Compared with bi-cubic interpolation and bilinear interpolation,the TDAGI algorithm is more accurate.Furthermore,the TDAGI algorithm has the advantage of gradient keeping.Therefore,TDAGI can be used as an alternative method in the dose interpolation of TPS in IMRT.

Magnetic Fields Affect Alcoholic Liver Disease by Liver Cell Oxidative Stress and Proliferation Regulation.

It is well known that alcohol consumption leads to substantially increased free radical levels and health risks, which lacks effective treatment besides alcohol abstinence. Here, we compared different static magnetic field (SMF) settings and found that a downward quasi-uniform SMF of ~0.1 to 0.2 T could effectively alleviate alcohol-induced liver damage and lipid accumulation and improve hepatic function. SMFs of two different directions can reduce the inflammation, reactive oxygen species levels, and oxidative stress in the liver, while the downward SMF had more obvious effects. Moreover, we found that the upward direction SMF of ~0.1 to 0.2 T could inhibit DNA synthesis and regeneration in hepatocytes, which caused detrimental effects on the lifespan of "heavy drinking" mice. In contrast, the downward SMF prolongs survival of "heavy drinking" mice. On one hand, our study shows that ~0.1 to 0.2 T moderate quasi-uniform SMFs with a downward direction have great promises to be developed into a physical method to reduce alcohol-induced liver damage; on the other hand, although the internationally recognized upper limit for SMF public exposure is 0.4 T, people should also pay extra attention to SMF strength, direction, and inhomogeneity that could generate harmful effects on specific severe pathological conditions.

Life on Magnet: Long-Term Exposure of Moderate Static Magnetic Fields on the Lifespan and Healthspan of Mice.

All living organisms on the Earth live and evolve in the presence of the weak geomagnetic field, a quasi-uniform static magnetic field (SMF). In the meantime, although the effects of moderate and high SMFs have been investigated on multiple aspects of a living organism, a long-term SMF exposure of more than 1 year has never been reported. Here, we investigated the influence of a moderate SMF (70-220 mT head-to-toe) long-term continuous exposure (1.7 years) to two different SMF directions on healthy male C57BL/6 mice. We found that not only was the lifespan of the mice prolonged, but their healthspan was also improved. The elevated plus maze test and open field test show that SMFs could significantly improve the exploratory and locomotive activities of the aged mice. The Morris water maze test shows that SMFs could improve their spatial learning ability and spatial memory. Tissue examinations reveal that SMFs have an ameliorative effect on oxidative stress in the brain of aged mice, which was reinforced by the cellular assays, showing that SMFs could protect the PC12 cells from D-gal-induced senescence by increasing superoxide dismutase, catalase, and reducing the malonaldehyde levels. Therefore, our data show that the 1.7-year SMF exposure can improve both the lifespan and healthspan of naturally aged mice due to reduced oxidative stress, which indicates that SMFs have the potential to be used as an adjuvant physical therapy to reduce the ageing-induced health risks to benefit animals, and even humans.

Static Magnetic Fields Protect against Cisplatin-Induced Kidney Toxicity.

Cisplatin is one of the most widely used anti-cancer drugs that can effectively inhibit the growth of multiple types of cancer. However, its clinical application is limited by its severe side effects, especially kidney toxicity, caused by cisplatin-induced oxidative stress, inflammation and kidney cell apoptosis. Here, we found that moderate (a few hundred mT) quasi-uniform static magnetic fields (SMFs) could inhibit cisplatin-induced renal proximal tubular cell death, especially the vertically downward direction SMF. RNA-seq experiments demonstrate that SMFs induced differential gene expressions that are closely associated with oxidative stress, apoptosis, cytokine production, transmembrane transport and DNA repair. In vivo experiments show that SMFs can reduce cisplatin-induced kidney injury in cisplatin-administrated tumor-bearing mice by reducing oxidative stress, inflammation and cell apoptosis. Furthermore, high-dose cisplatin-induced acute nephrotoxicity can be effectively alleviated by SMF treatment of as little as one day, which significantly reduced the reactive oxygen species levels in kidneys and prolonged the mice's survival. Moreover, the concentration of cisplatin in the kidney was significantly attenuated in SMF-treated mice. Therefore, our study demonstrates the effects of moderate SMFs as a novel physical method to reduce oxidative stress, and revealed their future potential to be used against cisplatin-induced kidney toxicity in cancer treatment.

A Static Magnetic Field Improves Iron Metabolism and Prevents High-Fat-Diet/Streptozocin-Induced Diabetes.

Type 2 diabetes (T2D) is a metabolic disorder with high prevalence and severe complications that has recently been indicated to be treatable by a combined static magnetic field (SMF) and electric field. We systematically compared four types of SMFs and found that a downward SMF of ∼100 mT could effectively reduce the development of hyperglycemia, fatty liver, weight gain, and tissue injury in high-fat-diet (HFD)/streptozocin-induced T2D mice, but not the upward SMF. The downward SMF markedly restored the Bacteroidetes population and reversed the iron complex outer membrane receptor gene reduction in the mice gut microbiota, and reduced iron deposition in the pancreas. SMF also reduced the labile iron and reactive oxygen species level in pancreatic Min6 cells in vitro and prevented palmitate-induced Min6 cell number reduction. Therefore, this simple SMF setting could partially prevent HFD-induced T2D development and ameliorate related symptoms, which could provide a low-cost and non-invasive physical method to prevent and/or treat T2D in the future.

Positron Emission Tomography Imaging of Lesions pH Using 11C-Labeled Bicarbonate.

OBJECTIVES: As acid-base imbalance is involved in many pathological processes, the capability to image tissue pH alterations in the clinic could offer new ways to detect disease and respond to treatment. In this study, the authors show that tissue pH can be imaged in vivo with 11C-labeled bicarbonate (H11CO3-) buffer and positron emission tomography (PET). METHODS: H11CO3- was produced by on-column NaOH adsorption. Biodistribution of H11CO3- in normal mice was determined. In addition, uptake studies and inhibition experiments of H11CO3- in the S180 fibrosarcoma-bearing mice and the inflammatory mice were investigated with PET imaging. The tumor and inflammatory interstitial pH was measured by a needle pH microelectrode. RESULTS: PET imaging demonstrated the high uptake of H11CO3- in mice tumor tissues and inflammatory tissues, which showed that the average tumor or inflammatory interstitial pH was significantly lower than the surrounding tissue. Administration of sodium bicarbonate in the drinking water increased the measured tumor pH, while the uptake of H11CO3- in mice model tissues had no change. Similarly, administration with ammonium chloride (NH4Cl) decreased the pH, whereas the unchanged uptake of H11CO3- in mice model tissues was also found. However, after administration of acetazolamide, the low uptake of H11CO3- in mice model tissues was observed. CONCLUSIONS: H11CO3- solution is an endogenous bicarbonate buffer tracer that can be injected into patients without toxicity. H11CO3- PET can be used clinically to image pathological processes that are associated with acid-base imbalance, such as cancer and inflammation.

Cell penetrating peptide of sodium-iodide symporter effect on the I-131 radiotherapy on thyroid cancer.

The aim of the present study was to clarify whether the cell penetrating peptide of sodium-iodide symporter (NIS) has an effect on the I-131 radiotherapy of thyroid cancer. Firstly, we combined the HIV-1 TAT peptide (a cell penetrating peptide, dTAT) and established a nanoparticle vector (dTAT NP) to study the delivery efficiency of this cell-penetrating strategy for tumor-targeted gene delivery. dTAT NP was transfected into cultured TPC-1 cells as a model to study the effects of I-131 radiotherapy on thyroid cancer. Reverse transcription-quantitative polymerase chain reaction and western blotting results showed that the mRNA and protein expression levels of NIS in the transfected TPC-1 cells were substantially higher than in the negative control cells. MTT and flow cytometric analyses demonstrated that the cell growth and apoptosis rates of the TPC-1 cells were significantly inhibited and activated, respectively, by treatment with dTAT NP. The results of DAPI staining showed that treatment with dTAT NP visibly increased the nuclear apoptosis rate of the TPC-1 cells. The effect of dTAT NP on TPC-1 cells was associated with the promotion of caspase-3 and downregulation of the PI3K/Akt signaling pathway. In summary, the present data provide a pre-clinical proof-of-concept for a novel gene delivery system that efficiently delivers NIS to the targeted cancer cells and presents a satisfactory efficacy. This approach may offer an effective strategy for improving thyroid cancer gene therapy.

[Therapeutic effects of strontium-89 against osseous metastases of lung cancer: analysis of 126 cases].

OBJECTIVE: To investigate the therapeutic effects of strontium-89 against osseous metastases of lung cancer. METHODS: A total of 126 patients with osseous metastases of lung cancer received strontium-89 treatment ((89)SrCl(2)) at the dose of 148 MBq given through a single intravenous injection. The analgesic effect was evaluated by the changes in the degree, frequency and scores of the pain, and the therapeutic effect assessed by observing the changes in the number and volume of osseous lesions after therapy and compared between different pathological types of lung cancer by Ka-square test. RESULTS: Within 6 months after the injection, the total pain relief rate was 70.6% (89/126), including 25 (19.8%) cases with pain vanished, suggesting significant alleviation of the pain intensity by the treatment (u=5.361, P<0.01). The frequency of pain was reduced in 78.6% (99/126) of the cases (u=4.589, P<0.01), and the average score of pain decreased significantly from 7.54+/-3.29 to 4.19+/-4.38 (t=6.865, P<0.001). The number and size of lesions decreased by more than 25% in 57 cases, showing a total efficacy rate of 45.2% (57/126). No significant difference was noted in the therapeutic effects among the 4 pathological types of lung cancer (P>0.05). CONCLUSIONS: Strontium-89 is effective for pain relief and tumor focus confinement in osseous metastases of lung cancer. No significant difference has been found in its effect between 4 different pathological types of lung cancer.

[Diagnostic value of 99mTc-MIBI brain SPECT for brain glioma].

OBJECTIVE: To evaluate the value of (99m)Tc-MIBI brain single-photon emission computerized tomography (SPECT) in diagnosis of glioma. METHODS: Fifty-nine patients with glioma, 6 with brain abscess and 9 healthy controls underwent (99m)Tc-MIBI brain SPECT, and the diagnostic indices such as the sensitivity, specificity and accuracy were calculated. The tumor to non-tumor (T/NT) ratios were calculated according to the region of interest (ROI) and compared between the glioma group, healthy control group and brain abscess group by t test. RESULTS: Among the 59 cases of glioma, 51 showed positive results in (99m)Tc-MIBI SPECT, along with one of the healthy controls and 4 of brain abscess patients. The sensitivity, specificity and accuracy of the diagnosis were 86.4%, 66.7% and 82.4%, respectively. The T/NT ratio of brain glioma group was 2.6+/-1.2, significantly higher than that of normal group (t=3.6199, P<0.001) and brain abscess group (t=2.1327, P<0.05). CONCLUSION: (99m)Tc-MIBI brain SPECT is sensitive for diagnosis of brain glioma, and can distinguish malignant from benign lesions effectively.

[Diagnosis of osseous metastases of malignant tumors by bone scanning combined with bone alkaline phosphatase detection].

OBJECTIVE: To assess the diagnostic value of bone alkaline phosphatase (B-AKP) detection in diagnosis of osseous metastases of malignant tumors. METHODS: Bone scanning and B-AKP detection were performed in 106 patients with malignancies. According to the findings in bone imaging and clinical symptoms, the patients were divided into bone metastases group (BM) and non-bone metastases group (NBM), between whom B-AKP was compared by t test. According to the number of osseous lesions on bone imaging, the patients were graded and B-AKP was compared between the 4 grades. Correlation analysis was performed between B-AKP level and the number of osseous lesions. RESULTS: Among the 106 patients, bone scanning found osseous metastases in 68 patients. For diagnosing osseous metastases, the sensitivity, specificity, PPV and NPV of B-AKP detection were 89.7%, 52.6%, 77.2% and 74.0%, respectively. B-AKP was 28.4+/-14.8 microg/L in BM group and 12.8+/-7.6 microg/L in NBM group, showing significant difference (t=6.056, P<0.001). B-AKP was 13.9+/-6.8 microg/L, 17.2+/-9.4 microg/L, 23.8+/-10.4 microg/L and 49.5+/-17.6 microg/L in patients of grade 0, 1, 2, and 3, respectively, showing significant difference by comparisons between the grades (P<0.05) except for that between grades 0 and 1 (t=1.320, P>0.05) and between grades 1 and 2 (t=1.803, P>0.05). B-AKP was 19.6+/-4.2 microg/L in patients with single hot focus and 13.1+/-3.4 microg/L in patients with single cold focus (t=2.570, P<0.05). Correlation analysis showed that there was low-degree correlation between B-AKP level and the number of osseous lesions (r=0.751, P<0.01). CONCLUSIONS: B-AKP level detection and bone imaging yield consistent results. For diagnosis of osseous metastases in patients with malignant tumor, bone scanning is the primary choice but in cases of single hot lesions, B-AKP should be performed to prevent missed diagnosis; for false positive lesions, B-AKP should also be detected to prevent misdiagnosis.

[Lower limb hemodynamic evaluation in patients with diabetic foot using 99mTc-methylene diphosphonate three-phase bone scintigraphy].

OBJECTIVE: To evaluate the efficacy of (99m)Tc-methylene diphosphonate (MDP) bone scintigraphy in diagnosis of diabetic foot. METHODS: (99m)Tc-MDP three-phase bone imaging was performed in 56 patients with diabetic foot and 36 non-diabetic control subjects, each foot was analyzed independently. The radioactive concentration per pixel hence the foot to tibia ratio (R(m/t)) was calculated and the time-radioactivity curve of each region of interest generated. From the curve the perfusion time (Tp) was read and the velocity of uptake rate (V) of the foot calculated. The indices such as R(m/t), Tp and V were compared between the two groups by t test, and the diagnostic indices such as sensitivity, specificity, accuracy, positive prediction value and negative predictive value were compared using u test. RESULTS: In the control group, the Tp, V and R(m/t) were 32.9+/-9.8 s, 2.301+/-0.754 counts/s and 0.85+/-0.29, respectively, which were 36.1+/-15.3 s, 1.574+/-0.341 counts/s and 0.72+/-0.31 respectively in the diabetic group. Tp was not significantly different (t=1.693, P>0.05) between the two groups, as was V (t=8.396, P<0.001) and R(m/t)(t=2.759, P<0.01). When V was used as the index, the sensitivity, specificity, and accuracy were 80.2%, 82.8% and 81.5%, respectively, and those for R(m/t) were 65.2%, 68.8% and 67.3%, respectively. By comparison, the sensitivity (u=2.3274, P<0.05) and specificity (u=2.4068, P<0.05) of V were significantly higher than those of R(m/t). CONCLUSIONS: (99m)Tc-MDP three-phase bone imaging can identify decreased uptake rate and R(m/t) in the diabetic foot, and the former index can be more sensitive and specific to define the hemodynamics in the diabetic foot. This technique may detect hemodynamic abnormity in early stage and greatly assist the diagnoses and treatment.

Radiosensitivity of hepatocarcinoma cell line BEL-7402.

OBJECTIVE: To assess the radiosensitivity of human hepatocarcinoma cell line BEL-7402. METHODS: Human hepatocarcinoma cell line BEL-7402 was cultured in vitro and then subjected to exposure to 6 MV X-ray at the doses ranging from 0 to 10 Gy. The survival rate of the cells following the exposure was assessed by determining the colony-forming units during further cell culture 12 to 14 d after the exposure, and the parameters for the radiosensitivity calculated. RESULTS and CONCLUSION: The parameters of BEL-7402 cells (D0=1.6, Dq=1.3, n=2, 4, SF2=0.63+/-0.05 Gy) demonstrates a high sensitivity of the cells to radiation.

[Repair of tibial defect with tissue-engineered bone graft and radionuclide bone imaging in goats].

OBJECTIVE: To observe the effect of tissue-engineered bone grafts in repairing large tibial defect in goats, and assess the value of radionuclide bone imaging in monitoring the therapeutic effect of this approach. METHODS: Tibial defects measuring 2 cm was artificially made in the left tibia of 27 normal goats that were subsequently divided into 3 groups (9 each) to undergo treatment with tissue-engineered bone grafts, artificial bone grafts or without any grafts (as control group) respectively. The tissue-engineered bone grafts contained bone marrow stroma cells (BMSCs) of the goats and coral hydroxyapatite (CHAP), while the artificial bone grafts were from CHAP only. After the operations, radionuclide bone imaging was used to monitor the therapeutic effects at 2, 4 and 8 postoperative weeks. RESULTS: The 99mTc-MDP uptake of the region of interest (ROI) and the target to non-target ratios (T/NT) of the control group did not indicate any process of revascularization or bone regeneration. An increasing tendency of the revascularization and bone regeneration, in contrast, was observed in goats receiving the artificial bone grafts, a tendency that was far more obvious in the goats with tissue-engineered bone grafts. CONCLUSION: Tissue-engineered bone graft is eligible in repairing large defect in the caprine tibia, and radionuclide bone imaging may accurately monitor the revascularization and bone regeneration after the bone graft implantation.

[Evaluation of therapeutic effects of strontium-89 on osseous metastases of prostate cancer by bone scanning and B-AKP measurement].

OBJECTIVE: To evaluate the therapeutic effects of strontium-89 on osseous metastases of prostate cancer by bone scanning and bone alkaline phosphatase (B-AKP) measurement. METHODS: One week before and within 6 months after strontium-89 therapy, bone scanning and B-AKP measurement were performed in 73 patients with bone metastases of prostate cancer. 1. According to the number of osseous lesions on bone imaging, the patients were divided into Grade 0, 1, 2 and 3, and the numbers of bone lesions before and after therapy were compared by t-test. 2. Tumor to non-tumor ratios(T/NT) before and after treatment were calculated and compared. 3. Changes in B-AKP before and after therapy were compared. RESULTS: 1. Among the 73 patients, bone scanning revealed 618 bone lesions, averaging 8.6 +/- 7.4 before treatment. The number decreased to 349, averaging 3.8 +/- 6.7 after treatment, which showed a significant reduction (t = 4.079, P < 0.01). 2. After therapy, T/NT of bone lesions decreased significantly (t = 7.907, P < 0.01) from 5.36 +/- 4.67 to 3.17 +/- 2.95. 3. B-AKP decreased significantly (t = 3.349, P < 0.002) from (28.4 +/- 14.8) microgram/L to (20.9 +/- 11.7) microgram/L. 4. By bone scanning combined with B-AKP measurement, 5 false positive cases and 6 false negative cases were corrected. CONCLUSION: There is certain complementarity between bone scanning and B-AKP measurement, and they should be used in a combined way to achieve accurate evaluation of the therapeutic effects of strontium-89.

[In vivo and in vitro stability of ¹³¹I-Herceptin and its form of existence in the blood of rabbits].

OBJECTIVE: To evaluate the in vivo and in vitro stability of (131)I-Herceptin and its form of existence in the blood. METHODS: Herceptin was labelled with iodine-131 using the Iodogen method. (131)I-Herceptin was stored at 4 degrees celsius for 3, 24, 48, 72 and 96 h, and the radiochemical purity (RCP) was measured by high performance liquid chromatography (HPLC). Five rabbits received injections of (131)I-Herceptin and at 1, 3, 6, 24, 48, 72, 96 and 120 h after the injection, blood samples were taken to measure the RCP of (131)I-Herceptin in the serum, and the radio count of the serum and blood cells was calculated. RESULTS: The baseline RCP of (131)I-Herceptin was (94.9±2.7)%. The RCP was stable after placement at 4 degrees celsius for not over 72 h (F=15.985, P<0.001), but was significantly lowered to (82.6±2.8)% after preservation for over 72 h (t=9.971, P<0.001). Within the time of 1.0 to 96 h after injection in rabbits, (131)I-Herceptin existed mainly in the serum with a radio count of 81%-87%; 24 h after the injection, the RCP of (131)I-Herceptin in the serum was significantly lowered to (75.4±3.9)% (t=6.564, P<0.001). CONCLUSION: Storage at 4 degrees celsius for no more than 72 h does not obviously affect the activity of (131)I-Herceptin in terms of RCP. After injection in rabbits, (131)I-Herceptin exists mainly in the serum and its radiochemical purity remains stable within 24 h, after which obvious degradation occurs.