Objective To study the effect of two-step pretargeting radioimmunotherapy of CD45 McAb and 188Re-Avidin on lymphoma Raji cell line.Methods The CD45 McAb and Avidin were directly labeled with 188Re,and the labeling efficiency and radiochemical purity were measured by the paper chromatography.The specific binding test and competition binding test between 188 Re-CD45 McAb and Raji cells in vitro were also performed.CCK-8 assay was used to determine the inhibition effect on Raji cell proliferation in the pretargeted group,188Re-CD45 McAb,188Re-Avidin and 188ReO4 groups,then the cell survival and proliferation inhibition rate were calculated.Results The specific cell binding rate of 188Re-CD45 McAb with Raji cells was (70.92 ± 1.91) ％,in the competition group,the binging rate of 188Re-CD45 McAb with Raji cells was only (7.96 ± 0.87)％.The Raji cells proliferation was inhibited in all groups with 188Re radiolabel,and the inhibition rate was positively correlated with the radioactivity dose (r=0.907-0.992,P ＜0.05).However,at the same dose,the inhibition effect in the group of two-step pretargeting at each time point were all stronger than those of 188Re-CD45 McAb,188Re-Avidin and 188 ReO4-alone (t =124.76-607.98,P ＜ 0.05).But there was no significantly statistical difference in the inhibitory effect between the groups of 188Re-Avidin and 188ReO4-(P ＞ 0.05).Conclusions It is confirmed that 188Re-CD45 McAb could be specifically bound to Raji cells,and the two-step pretargeting of CD45 McAb and 188Re-Avidin has obvious inhibitory effect on the Raji cell proliferation.

Objective To establish rat models of extrahepatic biliary atresia,and to observe the characteristics of 99Tcm-MIBI hepatobiliary scintigraphy and evaluate its association with the expression Pglycoprotein (P-gp) in intestinal tissues.Methods A total of 12 SD rats were randomly divided into the normal control group (3 rats) and the group of common bile duct ligation (CBDL;9 rats).CBDL was used to establish the rat model of extrahepatic biliary atresia.99Tcm-MIBI hepatobiliary scintigraphy was performed at 2,3 and 4 weeks after ligation in the CBDL group and normal control group with continuous dynamic acquisition (3 min/frame) for 30 min and then delaying imaging at 30 min,1,2 and 3 h.After that,all rats were sacrificed,and the blood samples were taken out for the determination of serum ALT,AST,TBIL,DBIL,IBIL,ALP,γ-GT and TBA,and the tissues of duodenum,jejunum,ileum,colon and cecum were taken out for analyzing the expression level of P-gp by immunohistochemistry.Two-sample t test and one-way analysis of variance were used.Results Compared with the normal control group,the serum levels of ALT,AST,TBIL,DBIL,IBIL,ALP,γ-GT and TBA were significantly increasing at 2,3,4 weeks after ligation in CBDL group (t:-3.04 to-44.54,all P＜0.05).99Tcm-MIBI hepatobiliary imaging showed that there was radioactive accumulation in colon or cecum area,excluding the duodenum,jejunum and ileum area,at 3 h after intravenous injection of 99Tcm-MIBI in CBDL group.The results of immunohistochemistry showed that with the obstruction time prolonged,the expression levels of P-gp in duodenum,jejunum and ileum segments were gradually decreased (F=5.17,9.07,23.52;all P＜0.05),while the expression levels in the colon and cecum segments were not changed obviously (F=2.00,3.17;both P＞0.05).Conclusion 99Tcm-MIBI can be excreted through intestinal mucosa,and this process may be associated with P-gp expression.

Objective To investigate the value of hepatobiliary scintigraphy combined with total bile acid (TBA) and γ-glutamyhransferase(γ-GT) detection in the differential diagnosis of persistent jaundice induced by infantile hepatitis syndrome(IHS) and congenital extrahepatic biliary atresia(EHBA).Methods A retrospective analysis of 60 infants with persistent jaundice undertaking 99Tcm-diethylacetanilide iminodiacetic acid (EHIDA) hepatobiliary scintigraphy was done in Nanfang Hospital by single photon emission computed tomography(SPECT).Meanwhile,these infants' sera were collected and separately detected by AU5431 automatic biochemical assay;the sensitivity,specificity and accuracy of hepatobiliary scintigraphy with TBA and γ-GT were evaluated.Results The sensitivity to 99Tcm-EHIDA hepatobiliary scintigraphy in the diagnosis of IHS and EHBA were 100.00％ (17/17 cases) and 67.57％ (25/37 cases),the specificity was 67.57％ (25/37 cases) and 100.00％ (17/17 cases),and the accuracy was 77.78％ (42/54cases) and 77.78％ (42/54 cases),respectively.The levels of TBA and γ-GT were higher in infants with EHBA than those with IHS(U =209.0,19.5,all P ＜0.05),and ROC curve analysis indicated that TBA in the IHS group and γ-GT in EHBA group had some diagnostic value[area under curve (AUC) =0.736,0.968,respectively].99Tcm-EHIDA hepatobiliary scintigraphy combined with TBA and γ-GT analysis suggested when intestinal non-radioactive imaging was shown,TBA was 98.5 μmol/L and γ-GT was 298 U/L,the sensitivity,specificity and accuracy of diagnosis of EHBA were 100.00.00％ (17/17 cases),100.00％ (37/37 cases) and 100.00％ (54/54 cases) in a serial test.Conclusions Hepatobiliary scintigraphy combined with TBA and γ-GT examination can effectively identify EHBA and IHS earlier,noninvasively and safely,which have important role in further treatment in infants with persistent jaundice.

OBJECTIVETo establish a two-step pretargeting approach to lymphoma radioimmunoimaging in mice using biotinynaled CD45 monoclonal antibody (McAb) and (188)Re-avidin in a tumor-bearing mouse model.

METHODSSix Nod-Scid mice bearing lymphoma cell xenograft were randomized to receive either an intravenous injection of 50 µg/200 µL biotinyled CD45 McAb followed 24 h later by an intraperitoneal injection of 3.7 MBq (50 µg/100 µL) (188)Re-avidin (two-step pretargeting group), or a single intravenous injection of 3.7 MBq (100 µg/100 µL) (188)Re-CD45 McAb (control group). SPECT was performed at 0.5, 1, 6 and 23 h post-injection to characterize (188)Re isotope biodistribution. At 24 h pos-injection, the mice were sacrificed for measurement of radioactivity uptake in the tumor and normal tissues and calculation of the tumor-to-non-tumor (T/NT) ratios.

RESULTSSPECT showed that the two-step pretargeting method resulted in a low radioactivity in the blood pool during the imaging and a concentrated radioactivity in the liver and spleen. The transplanted tumor began to be displayed at 1 h post-injection and was clearly displayed at 1-6 h; the images were clear even at 23 h. With the two-step pretargeting method, the radioactive uptake at 24 h post-injection were (1.34∓0.52)%, (6.77∓2.32)%, and (2.81∓1.25)% in the tumor, kidney and liver, respectively, with low radioactivity levels in other organs and high tumor/blood and tumor/muscle ratios (4.28∓0.82 and 8.00∓0.88, respectively). In the control group, SPECT revealed intense radioactivity in the liver, spleen, and kidneys with obscure display of the tumor; at 20 h, the radioactivity in the blood pool remained high but that in the tumor was low, and the tumor/blood and tumor/muscle ratios at 24 h were only 0.58∓0.06 and 3.21∓0.24, respectively.

CONCLUSIONCompared with (188)Re-CD45 McAb, the two-step pretargeting approach exhibits a good specificity in targeting lymphoma with an increased T/NT ratio in mice and allows early tumor display at 1 h post-injection.

Animals ; Antibodies, Monoclonal ; Avidin ; Disease Models, Animal ; Lymphoma ; diagnosis ; Mice ; Mice, Nude ; Neoplasm Transplantation ; Radioimmunodetection ; Tissue Distribution ; Tomography, Emission-Computed, Single-Photon

Objective To investigate the effect of local injection of phage lyase LysGH 15 into rabbits' knee joint on the systemic inflammation,local infection around knee joint prosthesis and biofilm formation on the prosthesis surface after their knee joint prosthesis implantation surgeries.Methods Models of Staphylococcus aureus infection on rabbits' knee joint prosthesis after prosthesis implantation were built and divided into experimental group for intra-articular injection with lyase and control group for injection with saline into their joint cavity.The phage lysin LysGH15 was synthesized and purified.On the 1st,2nd and 3rd day after the inoculation with Staphylococcus aureus bacteria into the rabbits' knee joint cavity of the prosthesis implanted side,0.5 ml diluted solution of LysGH15 was injected into the knee joint cavity with infection around the prosthesis for the experimental group rabbits and 0.5 ml saline was injected into the corresponding joint cavity for control group rabbits as blank contrast.On the 1st,3rd,7th and 14th day,blood samples were collected from their ear vein to make plasma procalcitonin test for evaluation of rabbits' systemic infection.After the last time for collection of venous blood samples,these rabbits were killed instantly and their knee joints of prosthesis implantation side were dissociated.Tissue around the prosthesis was processed with HE staining to observe and evaluate the local infection and tissue necrosis around the prosthesis.The biofilm formation on the prosthesis surface was evaluated with semi quantitative method after the observation of samples under scanning electron microscope (SEM).Results After the injection of LysGH15 in experimental group,their serum procalcitonin level,which worked as the systemic inflammatory marker,decreased rapidly especially on the 3rd day after lysin injection.Compared with the control group,the infection degree of experimental group significantly decreased.In the experimental group,the infection and necrosis degree of the tissue surrounding the prosthesis were significantly lower in the experimental group than those in the control group.The semi quantitative scores were conducted for these samples and graded to make rank sum test.The difference between the two groups was statistically significant (U=2.4948,P=0.0126).There was a statistically significant difference in the rank sum test between the two groups in the quality of biofilm formation (U=2.2539,P=0.0242).Conclusion Phage lysin LysGH15 can alleviate the rabbits'systemic inflammation caused by Staphylococcus aureus bacteria after their knee joint prosthesis implantation,reduce the extent of damage caused by infection and inflammation to the tissue around the prosthesis,and inhibit the formation of bacterial biofilm on the surface of implanted prosthesis.