STUDY ON THE ACCUMULATION OF ENRICHED URANIUM UO_2F_2 IN SUBCELLULAR LEVEL BY ELECTRON MICROSCOPIC AUTORADIOGRAPHY

In this paper we try to study the retentive peculiarity of soluble enriched uranium UO2F2 in subcellular level by electron microscopic autoradiography. The early dynamic accumulation of radioactivity in the body showed that enriched uranium UO2F2 was chiefly localized in kidney, especially accumulated in epicyte of kidney near- convoluted tubule. In liver cells, enriched uranium UO2F2 at first deposited in the nucleus and the cytoplasm, then accumulated in mitochondria selectively and lysosome as well. The electron microscopic autoradiographic study showed that the dynamic retention of radioactivity of enriched uranium UO2F2 in skeleton rose steadily throughout the exposure. Enriched uranium UO2F2 chiefly deposited in nucleus and mitochondria of the osteoblast as well as osteoclast.

Effects of compound rehmannia formula on dopamine transporter content in the corpus striatum of Parkinson's disease rats treated with levodopa

Long-term application of levodopa （L-3, 4-dihydroxyphenylalanine, L-DOPA） for Parkinson＇s disease can lead to adverse effects and reduce the amount of dopamine transporter （DAT） in the corpus striatum. The present study attempted to vedfy whether increasing the amount of DAT can reduce the adverse effects of L-DOPA. The specific radioactive uptake value of DAT in the corpus striatum of the lesioned hemisphere was significantly decreased, but was significantly increased following administration of compound rehmannia formula [Radix rehmanniae preparata （prepared rehmannia root）, Concha margantifera usta （nacre）, Radix paeoniae alba （white peony alba）, Radix salviae miltiotThizae （Danshen root）, Scorpio （scorpion）, green tea] for 4 weeks. The changes in DAT 1251-beta-carbomethoxy-3 beta-（4-iodophenyl） tropane autoradiography were consistent with those in radioactivity. The results revealed that the compound rehmannia formula can reduce the adverse effects of L-DOPA in treating Parkinson＇s disease, possibly by increasing the amount of DAT.

The Regulatory Action of Radix Astragali on M-Cholinergic Receptor of the Brain of Senile Rats

The changes in density of M-cholinergic receptors in different areas of senile rats and the regulatory action of Huang Qi (黄芪Radix Astragali, a drug for warming yang and replenishing qi) were observed by autoradiography. The results showed that the gray scale displayed in brain sections was clear and mainly distributed in the cortex, hippocampus and striate body, while that due to nonspecific combination was negligible. The gray scale in the cortex, hippocampus and striate body of the experimental group was markedly lower than that in the young control rats, decreased respectively by 24.87%, 14.12% and 12.76% (all P<0.05); but it was obviously higher than those in the senile control rats, increased respectively by 24.15%, 14.38% and 13.47% (P<0.05). The data indicate that Huang Qi (黄芪Radix Astragali) may up-regulate the decreased density of M-cholinergic receptors in the brain of senile rats.

Quantitative Autoradiographic Study on Receptor Regulation in the Basal Ganglia in Rat Model of Levodopa-induced Motor Complications

In order to study neurotransmitter receptor regulation in the basal ganglia involved in the functional changes underlying levodopa-induced motor complications, quantitative autoradiography was used to observe receptor bindings of dopamine D1 and D2, N-methyl-D-aspartate （NMDA）, amino-3-hydroxy-5-methylisoxazole propionic acid （AMPA） and amino butyric acid （GABA） in the basal ganglia of rats that had unilateral nigrostriatal lesions and had been chronically treated with levodopa until motor complications developed. The rats were randomly assigned to three groups： normal, denervated and treatment-complicated groups. The results showed that response duration to levodopa became progressively shorter and abnormal involuntary movement （AIM） score was progressively increased during the course of levodopa treatment. Chronic treatment augmented D1 receptors more than denervation, and reduced D2 receptors that were also increased by dopamine denervation. Striatal NMDA receptors were substantially up-regulated in the treatment-complicated group. Levodopa treatment did not change receptors of nigral AMPA, pallidal GABA, and subthalamic GABA, which remained the same as that in denervation group. However, chronic treatment reversed the increase of nigral GABA receptors caused by the lesion. It was concluded that a shortening of response duration and AIM mimicked levodopa-induced motor complications of Parkinson＇s patients. These data suggested that up-regulation of dopamine D1 and NMDA receptors in the striatum leads to an imbalance of stimulation through the striatal output pathways, which is associated with levodopa-induced motor complications.

Long-term existence of cerebral hypoxic tissue in a rat model of cerebral ischemia/reperfusion injury

BACKGROUND： Hypoxic tissue surrounding the ischemic core may represent the ischemic penumbra following cerebral infarction. However, some studies have shown that the duration of ischemic tissue is longer than previously believed. OBJECTIVE： To clarify whether cerebral hypoxic tissue could survive long-term and whether it is altered in rats following cerebral infarction; to establish an ischemiaJreperfusion model in which hypoxic tissue exists for extended periods of time. DESIGN, TIME AND SE＇I-I＇ING： A completely randomized grouping and controlled experiment was performed at the Experimental Animal Center of Sun Yat-sen University and Medical Research Center, the Second Affiliated Hospital of Sun Yat-sen University between June and December 2008. MATERIALS： 4,9-diaza-3,3,10,10-tetramethyldodecan-2, 11 -dione dioxime （BnAO） （HL91）, used as the hypoxic marker for autoradiography, was supplied by the Beijing Syncor Star Medicinal, China, and the flesh eluent Na99TcmO4 to mark HL91 was supplied by Guangzhou Medical Isotope Center of the China Institute of Atomic Energy. 2-（2-nitro-1H-imidazole-l-yl）-N-（2,2,3,3,3-pentafluoropropyl） acetamide （EF5） and its antibody ELK3-51, used as a hypoxic marker for immunofluorescence, were supplied by the University of Pennsylvania, USA. METHODS： Male Sprague Dawley rats were randomly divided into four groups： 1.5-hour ischemiaJreperfusion group （1.5 h IR）, 2-hour ischemiaJreperfusion group （2 h IR）, 3-hour ischemiaJreperfusion group （3 h IR）, and permanent ischemia （PI） group, with 21 rats in each group. The middle cerebral artery occlusion model was established using the intraluminal suture method, while reperfusion was performed by removing the suture at each observation time point. However, in the PI group, the suture was left in the artery. MAIN OUTCOME MEASURES： Area and average absorbance of fluorescence, representing hypoxic tissue, were measured by image-analysis. RESULTS： Autoradiography revealed positive hypoxia at days 1 and 14 postoperatively in the 1.5 h IR group. Immunohistochemistry results demonstrated that hypoxic tissue existed in the 1.5 h IR group on days 1, 3, 7, and 14, with decay of the area, but no significant weakening of fluorescent intensity. Hypoxic tissues were not observed at day 7 postoperatively in the 2 h and 3 h IR groups, as well as PI group. CONCLUSION： Similar to human cerebral infarction, hypoxic tissues in rats exist for an extended period of time following cerebral infarction, and diminish over even longer periods. Moreover, the 1.5 h IR rat model was the suitable model for studying long-term hypoxic tissue after cerebral infarction.

AUTORADIOGRAPHIC STUDY OF THE ATTRITION OF MIGRATING SCHISTOSOMULA IN THE SKIN OF MICE II.MICE CHALLENGED WITH NORMAL S.MANSONI CERCARIAE AFTER IMMUNIZATION WITH HIGHLY IRRADIATED CERCARIAE

The migratory pattern and attrition of75Se-labelled S.mansoni challenge cercariae in CF1mice immunized 0,1,3, or 5 times with 12kR-or 48kR-irradiated cercariae were investigatedby compressed organ autoradiography.Mice were percutaneously inoculated with 500-1000 cer-cariae for each immunization and with a known count of approximately 90 cercariae at adifferent site for challenge.The skin,lungs,liver,other organs,and catrcass were processedfor autoradiography.Hepatic and mesenteric perfusions for worm collection were alsosampled from day 19 through 34.In naive tnice,25% of challenge cercariae died in theskin.Skin attrition of challenge cercariae in mice immunized with 12kR-irradiated cercariaewas 43% with 1 immunization,54% with 3,and 58% with 5,whereas in mice immunized with48kR-irradiated cercariae,skin,attrition was48% with 1,63% with 3,and 76% with 5 immunni-zations.In all immunized mice,a high percentage of migrating sehistosomula died in the skinwithin 24 hours of a challenge infection.Utilizing autoradiography,it was found that thesilver foci created by single labelled worms were difficult to differentiate from those of pairedworms.This study documents the induction of acquired resistance against a challenge infectionin the skin by vaccination with highly irradiated cercariae,with the degree of attemtation ofimmunizing cercariae and the number of immunizations being closely related to the attritiotn.rate in the skin.Finally,we discuss the contradictory views concerning the site of attritiotn ofchallenge cercariae.

Absorptive process of ~3H-5-hydroxytryptamine in the intestinal lumen

Absorptive process of ~3H-5-hydroxytryptamine(~3H-5-HT)in the intestinal lumenwas studied by radiochemical method and autoradiography.The results indicated that ~3H-5-HTinjected into the intestinal lumen was rapidly absorbed.The absorptive peak appeared at 1 h af-ter ~3H-5-HT injection.Part of the absorbed ~3H-5-HT might enter the blood circulation,andthe other part was located specifically in the submucous plexus,myenteric plexus and some ep-ithelial cells.Whether these neurones and epithelial cells are 5-HT containing cells or are cellswith specific binding sites awaits further studies.

Autoradiographic Analysis of β-Adrenoceptors in Endomyocardial Biopsy Samples

We have studied the [125I] Pindolol ([125I]-PIN) binding to β-adrenergic receptors on endomyocardial biopsy samples through autoradiographic analysis. Minusculc amount of human endomyocardial tissues Was sectioned and incubated in [125I]-PIN, emulsion-coatcd covcrslips Were attached to the slides and then developed, fixed and staincd after exposure. The grain density was quantified using a computer image analyzer.The autoradiograms demonstrated the sites of cardiac β-receptorbinding with clear grains, and the non-specific binding was below 10%-20%' of the total binding. Linearregression analysis for the plot of specific cpm against specific grains at each concentration of [125I]-PINgave ay value of 0.99. Using this technique, we identified down-regulation of cardiac β-receptors inpatients with dilated cardiomyopathy (DCM) as compared with that of normal human subjects.

Effects of Propranolol on β-Adrenergic Receptor ofExperimental Acute Myocardial Infarction in Rats

By using receptor autoradiography to observe the distribution and density of receptors, the effects of propranolol, a β-blocker, on β-adrenergic receptor of experimental acute myocardial infarction (AMI) were studied. One week after ligation of proximate left anterior descend (LAD) coronary artery, [3H] DHA binding sites were markedly decreased in both infarctregion and non-infarct region. After treatment of propranolol (100μg/kg), the [3H] DHA binding sites were obviously increased in the infarct region, and they were further decreased in the non-infarct region. The ratio of [3H] DHA binding sites of the infarct region to non-infarct region was from 0. 24 at LAD ligation to 0. 87 after propranolol treatment, which was close to 0. 97 of control group (sham operation). The results indicated that the propranolol acted directly on myocardial β-adrenergic through the receptor regulation of the balance of β-receptors between the infarct region and non-infarct region, and improvement of the myocardial consonation and contraction synergism, thereby protecting the heart affected by AMI.

Radio Active Tracingsin Brains of Fetal Mice Conceilled by Dan Mice after with ^(125)I Labelled Toxoplasm a Gondii

I labelled T. gondii parasites were injected via tail vein into 14 day pregnant mouse( Kunming strain). Radioactive tracings of fetal train and pathologic changes were studiet. The results revealed that infection rates in the pregnant mice and in their fetal heads were 30.60% and 71.2% respectively. The ratio of the radioactivity between the fetal heads and the fetal trunks was 1.32-5.95 , being directly proportional to the durations of infection. Autoradiographs of light and electron microscopy indicated that the parasites appeared in the neurogliocytes of the fetal mice as early as 4 8 h post infection, and might be seen in the nucleus 48h after infection with degeneration and rupture of the cells. Numbers of the cranial nerve cells was distinctively reduced at 72h post infection. This study thus provided the experimental pathology evidence for the development of fetal neural malformation and cerebral lesions from T. gondil infected dam mouse.

Protective Effects of Berberine on Cerebral Ischemia in Mice and Rats

We have studied the [125I] Pindolol ([125I]-PIN) binding to β-adrenergic receptors on endomyocardial biopsy samples through autoradiographic analysis. Minusculc amount of human endomyocardial tissues Was sectioned and incubated in [125I]-PIN, emulsion-coatcd covcrslips Were attached to the slides and then developed, fixed and staincd after exposure. The grain density was quantified using a computer image analyzer.The autoradiograms demonstrated the sites of cardiac β-receptorbinding with clear grains, and the non-specific binding was below 10%-20%' of the total binding. Linearregression analysis for the plot of specific cpm against specific grains at each concentration of [125I]-PINgave ay value of 0.99. Using this technique, we identified down-regulation of cardiac β-receptors inpatients with dilated cardiomyopathy (DCM) as compared with that of normal human subjects.

A Dual-radiolabel Marker Quantifies Decrease in HT29 Xenograft Hypoxia Induced by Mild Temperature Hyperthermia

Purpose: In this project, we developed novel methods to quantify changes in tumor hypoxia following a mild tempera-ture hyperthermia (MTH) treatment in rat HT29 human colon adenocarcinoma xenograft. Materials and Methods: An exogenous hypoxia marker (IAZGP) was labeled with two radioisotopes of iodine (131I and 123I, respectively) to form two distinct tracers. The two tracers were injected into HT29-bearing nude rats 4-hour before and immediately following 41.5℃, 45-minute mild hyperthermia treatment. The distributions of the two hypoxia tracers were obtained by performing digital autoradiography on tumor sections, and image processing resulted in quantitative information at 50 μm pixel size. Results: Following the hyperthermia treatment, there was a remarkable decrease in hypoxia tracer binding. The average whole tumor hypoxia tracer targeted fraction in five animals changed from 30.3% ± 9.7% to 13.0% ± 5.3% after the hyperthermia treatment (P = 0.001). Detailed pixelby-pixel analysis of the image data revealed a decline in hypoxia tracer uptake after hyperthermia in most regions. However, there was concomitant emergence of some new regions of hypoxia identified by increased tracer uptake. In the control group, the overall hypoxia tracer targeted fraction remained almost constant, with some hypoxic tracer redistribution (putative acute hypoxia) observed. Conclusion: Reoxygenation occurred in the rat HT29 xenograft following MTH treatment. This was evident with preponderance of decreased hypoxia specific tracer uptake on tumor sections. Our methodology might be a useful tool in hypoxia study.

THE EXPRESSION OF RECEPTORS FOR VASOACTIVE INTESTINAL PEPTIDE AND SECRETIN IN COLON NEOPLASMS

Objective: To investigate the expression of the receptors for vasoactive intestinal peptide (VIP) and secretin in colon cancer. Methods: This study visualized and characterized the receptors for VIP and secretin in the sequence of human tumor-free colon, adenoma, carcinoma, liver metastasis using storage phosphor autoradiography. Results: Receptors for VIP and secretin were demonstrated in tumor-free colon and colon tumors. A decrease in affinity of VIP receptors was shown in the colonic liver metastasis (Kd = 3.30 nmol) when compared with tumor-free colon (Kd = 0.82 nmol). An up-regulation of receptors for secretin was found in colonic liver metastases. Conclusions: VIP and secretin were both expressed on normal colon tissues. Binding of VIP decreased while secretin increased in colonic liver metastasis. A down-regulation of receptors for VIP in colonic liver metastases may helpful to understand the migration of colon cancer.

GRAIN BOUNDARY SEGREGATION OF BORON IN NICKEL AND EFFECT OF MOLYBDENUM ADDITIONS

By means of particle tracking auloradiography it has been found that there exisls a strong tendency of equilibrium grain boundary segregation of B in Ni with binding energy of 18±2 kJ/mol.In Ni-Mo-B alloyshe segregelion is alleviated.For additions of 0.5% and 3% Ma lhe grain boundary binding energies of B de.crease to 14±lkJ/movand l3±1kJ/mol respectively.

THE EFFECTS OF DEPRENYL AND 1-METHYL-4-PHENYL-1, 2, 3, 6-TETRAHYDROPYRIDINE (MPTP) ON 2-DEOXYGLUCOSE UPTAKE IN THE MOUSE BRAIN

~3H-2-deoxyglucose (2-DG) autoradiographic technique was used to study the ef feets of a monoamine-oxidase-B (MAO-B) inhibitor deprenyl and the neurotoxin Ⅰ-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) on 2-DG uptake in the mouse brain. Following MPTP intoxication, 2-DG uptake was increased in the substantia nigra and lo(?)us ceruleus. At the same time, obvious abnormal behavior of the animals was induced. In the mice pretreated with deprenyl, 2-DG uptake was similar to that of control animal. Ab normal behavior. though present, was significantly milder than in mice given MPTP alone. It is concluded that MPTP interferes with the glucose metabolism in the substantia nigra and locus ceruleus and induces remarkable abnormal behavioral syndrome of mice. These deleterious effects can be blocked by pretreatment with deprenyl.

THE CHANGES OF PANCREATIC ACINAR CELL FUNCTION IN ACUTE NECROTIZING PANCREATITIS OF RATS

ObjectiFe To evaluate the changes of pancreatic acinar cell functions in the rats with acutenecrotizing pancreatitis (ANP). methods Seventy SD rats were randomized into two groups: experimental group(n=35) and control group (n=35). To prepare the experimental model, the retrograde injection of 5% sodiumtaurocholate into the pancreatic duct was used for inducing ANP. Radioactive tracing by L -3H-phenylalanineand autoradiography were performed for scoring the differences of changes of amino acid uptake, enzyme-proteinsynthesis and output from acinar cells in rats between both groups. Results No changes were observed in aminoacid uptake and enzyme -protein synthesis in rats with dotted and haemorrhagic necrotizing foci as compared withcontrol group. However, accumulated zymogen granules in the interstitial of acinar cells were seen in theexperimental group. Conclusion It indicates that in experimental ANP rats, the functions of acinar cells in bothamino acid uptake and protein synthesis were essentially normal, but the pathway of enzyme output was affectedinto ectopic secretion through the bottom or lateral cellular membrane of pancreatic acinar cell.

Synthesis of Gemcitabine-(C₄-<i>amide</i>)-[anti-HER2/<i>neu</i>] Utilizing a UV-Photoactivated Gemcitabine Intermediate: Cytotoxic Anti-Neoplastic Activity against Chemotherapeutic-Resistant Mammary Adenocarcinoma SKBr-3

Gemcitabine is a pyrimidine nucleoside analog that becomes triphosphorylated intracellularly where it competitively inhibits cytidine incorporation into DNA strands. Another mechanism-of-action of gemcitabine (diphosphorylated form) involves irreversible inhibition of the enzyme ribonucleotide reductase thereby preventing deoxyribonucleotide synthesis. Functioning as a potent chemotherapeutic gemcitabine promote decreases in neoplastic cell proliferation and apoptosis which is frequently found to be effective for the treatment of several leukemias and a wide spectrum of carcinomas. A brief plasma half-life in part due to rapid deamination and chemotherapeutic-resistance restricts the utility of gemcitabine in clinical oncology. Selective “targeted” delivery of gemcitabine represents a potential molecular strategy for simultaneously prolonging its plasma half-life and minimizing innocient tissues and organ systems exposure to chemotherapy. The molecular design and an organic chemistry based synthesis reaction is described that initially generates a UV-photoactivated gemcitabine intermediate. In a subsequent phase of the synthesis method the UV-photoactivated gemcitabine intermediate is covalently bonded to a monoclonal immunoglobulin yielding an end-product in the form of gemcitabine-(C4-amide)-[anti-HER2/neu]. Analysis by SDS-PAGE/chemiluminescent auto-radiography did not detect evidence of gemcitabine-(C4-amide)-[anti-HER2/neu] polymerization or degradative fragmentation while cell-ELISA demonstrated retained binding-avidity for HER2/neu trophic membrane receptor complexes highly over-expressed by chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3). Compared to chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3), the covalent immunochemotherapeutic, gemcitabine-(C4-amide)-[anti-HER2/neu] is anticipated to exert greater levels of cytotoxic anti-neoplastic potency against other neoplastic cell types like pancreatic carcinoma, small-cell lung carcinoma, neuroblastoma, glioblastoma, oral squamous cell carcinoma, cervical epitheliod carcinoma, or leukemia/lymphoid neoplastic cell types based on their reported sensitivity to gemcitabine and gemcitabine covalent conjugates.

GABA_A-Coupled Cl-/ HCO₃<sup style="margin-left:-10px">-</sup>-ATPase from Plasma Membrane of the Rat Brain: Role of HCO₃<sup style="margin-left:-10px">-</sup>in the Enzyme Activation

This work examines the influence of Cl- (2.5 - 125 mM) and HCO3- (2 - 30 mM) on the Cl-/HCO3- - ATPase complex of the neuronal membrane and this enzyme is a Cl--pump that is coupled to GABAA receptors. The greatest (44%) activating effect on the enzyme is found with HCO3- (20 - 30 mM), while the maximum activity occurs in the presence of a ratio of ~25 mM HCO3- /~5mM Cl-. Blockers of the GABAA receptor, namely bicuculline (10 - 50 μM) and picrotoxin (50 - 100 μM), inhibit this anion activation, whereas the HCO3- -ATPase activity is not sensitive to these ligands. Autoradiographic analysis of the spectrum of the partially purified enzyme phosphorylated with [γ-32P]ATP allowed us to distinguish three major 32P-labeled protein whose molecular weight are about 57, 53, and 48 kDa. In the presence of 5 mM Cl-/25mM HCO3- and 100 μM picrotoxin, the intensity of the phosphorylation of bands significantly decreased, thereby confirming the assumption about coupled of binding sites for anions and GABAA-ergic ligands. It was suggested scheme of Cl--transport through the plasma membrane by utilizing neuronal Cl-/ -HCO3- ATPase in the low (5 mM) Cl- and high (25 mM) HCO3- concentrations. The data demonstrated for the first time that the GABAA-coupled Cl-/ HCO3- -ATPase from rat brain neuronal membranes is maximally activated at a Cl-/HCO3- ratio of 1:5 and it remains stable at high concentrations of substrate and buffer.

Development of ^(18)F-labeled radiotracers for neuroreceptor imaging with positron emission tomography

Positron emission tomography （PET） is an in vivo molecular imaging tool which is widely used in nuclear medicine for early diagnosis and treatment follow-up of many brain diseases. PET uses biomolecules as probes which are labeled with radionuclides of short half-lives, synthesized prior to the imaging studies. These probes are called radiotracers. Fluorine-18 is a radionuclide routinely used in the radiolabeling of neuroreceptor ligands for PET because of its favorable half-life of 109.8 min. The delivery of such radiotracers into the brain provides images of transport, metabolic, and neurotransmission processes on the molecular level. After a short introduction into the principles of PET, this review mainly focuses on the strategy of radiotracer development bridging from basic science to biomedical application. Successful radiotracer design as described here provides molecular probes which not only are useful for imaging of human brain diseases, but also allow molecular neuroreceptor imaging studies in various small-animal models of disease, including genetically- engineered animals. Furthermore, they provide a powerful tool for in vivo pharmacology during the process of pre-clinical drug development to identify new drug targets, to investigate pathophysiology, to discover potential drug candidates, and to evaluate the pharmacokinetics and pharmacodynamics of drugs in vivo.

Synthesis of O-(2-[^(18)F]fluoroethyl)-L-tyrosine and its biological evaluation in B16 melanoma-bearing mice as PET tracer for tumor imaging

O-(2-[18F]fluoroethyl) -L-tyrosine([18F]FET) ,a fluorine-18 labeled analogue of tyrosine,has been syn-thesized and biologically evaluated in tumor-bearing mice. The whole synthesis procedure is com-pleted within 50 min. The radiochemical yield is about 40%(no decay corrected) and radiochemical purity more than 97% after simplified solid phase extraction. [18F]FET shows rapid,high uptake and long retention in the tumor as well as low uptake in the brain. The ratios of tumor-to-muscle(T/M) and tumor-to-blood(T/B) of [18F]FET are similar to those of [18F]FDG,but the ratios of tumor-to-brain(T/Br) are 2-3 times higher than that of [18F]FDG. Autoradiography of [18F]FET demonstrates a remarkable accumulation in melanoma with high contrast. It appears to be a probable competitive candidate for melanoma imaging with PET.