[Association between hyponatremia and hemodynamic and prognosis in patients with intermediate-risk acute pulmonary embolism]

Objective: To investigate the association between hyponatremia and hemodynamic and prognosis in patients with intermediate-risk acute pulmonary embolism. Methods: We retrospectively recruited 110 intermediate-risk acute pulmonary embolism patients (right ventricular dysfunction was confirmed by echocardiography and CT scan with or without the elevated levels of cardiac injury biomarkers) in the first and the second affiliated hospital of Harbin medical university from January 1,2011 to December 31, 2014. The patients were aged (58.4±14.9) years old.There were 49 males and 61 females.Patients were divided into 2 groups as non-hyponatremia group (plasma sodium>135 mmol/L, 93 cases) and hyponatremia group (plasma sodium≤135 mmol/L, 17 cases). Baseline clinical and hemodynamic parameters were obtained from these patients. All enrolled patients were followed up after discharge. Results: Heart rate ((106.7±21.9) beats per minute vs. (93.4±19.4) beats per minute, P=0.043),N-terminal pro B type natriuretic peptide (NT-proBNP, (5 561±1 593) ng/L vs. (1 738±589) ng/L, P=0.005), mean pulmonary arterial pressure((42.6±12.6)mmHg(1 mmHg=0.133 kPa) vs. (33.9±13.3)mmHg, P=0.046), mean right atria pressure ((20.6±8.1)mmHg vs. (10.2±5.4)mmHg, P=0.014), systolic right atria pressure ((27.3±9.0)mmHg vs. (15.6±6.1)mmHg,P=0.013) and diastolic right atria pressure(6.5(4.3,15.5)mmHg vs. 5.0(2.0,8.0)mmHg,P=0.016) were significantly higher in hyponatremia group than in non-hyponatremia group,and systolic blood pressure was significantly lower in hyponatremia group than in non-hyponatremia group ((113.5±21.9)mmHg vs.(129.5±28.9)mmHg, P=0.048). Pearson correlation analysis showed that hyponatremia was negatively correlated with heart rate (r=-0.262, P=0.043), NT-proBNP (r=-0.227, P=0.048), mean pulmonary arterial hypertension (r=-0.259, P=0.046), mean right ventricular pressure (r=-0.296, P=0.047), mean right atria pressure (r=-0.550, P=0.001), systolic right atria pressure (r=-0.552, P=0.001), and diastolic right atria pressure (r=-0.542, P=0.001). Kaplan-Meier survival analysis showed that the 1-year, 2-year and 3-year cumulative survival rates were 76.5%,70.6%,and 64.7% in the hyponatremia group, and 90.3%,86.0%,and 83.9% in the non-hyponatremia group(log-rank test, P=0.036).Multivariate Cox regression analysis showed that hyponatremia was an independent risk factor of death of intermediate-risk pulmonary embolism patient(HR=4.126, 95%CI 1.982-11.343, P=0.036). Conclusion: Hyponatremia is associated with adverse hemodynamic and reduced survival in patients with intermediate-risk pulmonary embolism.

Multiple ancient horizontal gene transfers and duplications in lepidopteran species

Eukaryotic horizontal gene transfer (HGT) events are increasingly being discovered yet few reports have summarized multiple occurrences in a wide range of species. We systematically investigated HGT events in the order Lepidoptera by employing a series of filters. Bombyx mori, Danaus plexippus and Heliconius melpomene had 13, 12 and 12 HGTs, respectively, from bacteria and fungi. These HGTs contributed a total of 64 predicted genes: 22 to B. mori, 22 to D. plexippus and 20 to H. melpomene. Several new genes were generated by post-transfer duplications. Post-transfer duplication of a suite of functional HGTs has rarely been reported in higher organisms. The distributional patterns of paralogues for certain genes differed in the three species, indicating potential independent duplication or loss events. All of these HGTs had homologues expressed in some other lepidopterans, indicating ancient transfer events. Most HGTs were involved in the metabolism of sugar and amino acids. These HGTs appeared to have experienced amelioration, purifying selection and accelerated evolution to adapt to the background genome of the recipient. The discovery of ancient, massive HGTs and duplications in lepidopterans and their adaptive evolution provides further insights into the evolutionary significance of the events from donors to multicellular host recipients.

Effects of insulinlike growth factor binding proteins on insulinlike growth factor-I biodistribution in tumor-bearing nude mice

This study evaluated the biodistribution and tumor targeting ability of radiolabeled insulinlike growth factor (IGF)-I. Because IGF binding proteins (IGFBPs) play a critical role in modulating IGF activity, the binding properties of 125I-labeled IGF-I to IGFBPs were investigated in vitro and in vivo. Because a large amount of the IGF-I was catabolized in vivo, we also studied the catabolism of IGF-I by tumor cells in vitro.

METHODS

125I-labeled-IGF-I was prepared using the chloramine T method. The biodistribution of 125I-labeled-IGF-I in tumor-bearing nude mice was compared between groups injected with 125I-labeled IGF-I alone or coinjected with unlabeled peptide. In vitro and in vivo chromatography studies were performed to evaluate the binding profile to IGFBPs and the degree of catabolites in serum as well as urine.

RESULTS

Data indicated that the binding of radiolabeled IGF-I to IGFBPs in vitro was dose dependent. However, there was a difference in complex formation between the serum and the heparinized plasma. In heparinized plasma, the radioactivity shifted from a 30- to 50-kDa complex to a 150-kDa complex and to a free ligand, because the binding of heparin with IGFBPs decreased its affinity for IGF-I. In plasma prepared with acid citrate dextrose a binding pattern identical to that of serum was observed. Moreover, there was a binding difference between mouse and rat. The 125I-labeled IGF-I catabolized very quickly when incubated at 37 degrees C but not at all at 4 degrees C. In tumor-bearing nude mice, the uptake of radioactivity in normal tissues decreased quickly, particularly in the kidneys. In mice coinjected with unlabeled carrier, the radioactivity in most normal tissues was lower and the tumor uptake higher than in the mice without carrier.

CONCLUSION

These data confirm that 125I-labeled IGF-I is avidly bound to IGFBPs, both in vitro and in vivo. By partially saturating this binding with unlabeled peptides, a favorable biodistribution was achieved, including faster clearance from normal tissue and higher tumor uptake, which resulted in better tumor-to-nontumor ratios. Nevertheless, the rapid catabolism and release of the radiolabel from tumor tissue result in a suboptimal targeting agent.

Methods to avoid adverse effect of circulating antigen on biodistribution of 125I-labeled antiTac dsFv: preinjection of intact antibody versus clearance of antigen with adivin-biotin system

The presence of circulating antigen may adversely affect the biodistribution of a radiolabeled antibody. The alpha subunit of the interleukin-2 receptor (IL-2Ralpha) is a cell-surface receptor that is overexpressed in various hematologic malignancies and in benign disorders. This receptor is cleaved from the cell surface and can be found in high concentrations in serum. Radiolabeled antiTac antibodies are being evaluated to target this receptor. Previous studies have shown that circulating soluble IL-2Ralpha (slL-2Ralpha) adversely affected the biodistribution of radiolabeled antiTac disulfide-stabilized (ds)Fv. In this study, we compared blocking and clearing sIL-2Ralpha to see which better minimized its interference with the biodistribution of radiolabeled antiTac dsFv.

METHODS

Two models of sIL-2Ralpha were used: one consisted of mice given intravenous sIL-2Ralpha and the other consisted of mice bearing SP2/Tac tumor xenografts (IL-2Ralpha positive), which shed sIL-2Ralpha. We biotinylated humanized antiTac monoclonal antibody (bt-HuTac) and radiolabeled it with 125I. We then compared its biodistribution with that of humanized antiTac monoclonal antibody IgG (HuTac). We examined the biodistribution of an injected dose of 125I-labeled antiTac dsFv after a preinjection of HuTac to block the sIL-2Ralpha epitope and after a preinjection of bt-HuTac, followed by an avidin chase.

RESULT

The 125I-labeled bt-HuTac cleared from the serum at a rate similar to that of HuTac. The avidin chase effectively cleared >92% of circulating 125I-labeled bt-HuTac within 20 min and was also effective in clearing sIL-2Ralpha. In comparison, HuTac prolonged the retention of 125I-labeled sIL-2Ralpha in the circulation, and the avidin chase decreased 125I-labeled sIL-2Ralpha to <18% of control. Although the two-step antigen-clearing system effectively cleared the antigen from the circulation and improved the biodistribution of 125I-labeled dsFv, the HuTac preinjection method had a similar but longer lasting beneficial effect on 125I-labeled dsFv biodistribution.

CONCLUSION

Preinjection of either HuTac or bt-HuTac with avidin chase improved the biodistribution of subsequently administered 125I-labeled antiTac dsFv by preventing the dsFv from binding to the sIL-2Ralpha, but the HuTac blocking method is simpler and longer lasting.

Inhibition of protein kinase C activity promotes heat-induced apoptosis in RIF-1 but not in TR-4 cells

PURPOSE

Inhibition of protein kinase C (PKC) activity has been demonstrated to reduce thermotolerance (TT), presumably by decreasing heat shock protein (HSP) production. Therefore, the interest was in evaluating this relationship further in two isogenic murine tumour cell lines: RIF-1 and its thermoresistant TR-4 selectant.

MATERIALS AND METHODS

TT was induced in RIF-1 and TR-4 cells (45 degrees C for 15 min, then 37 degrees C for 6 h) with or without Ro31-8220, a specific inhibitor of PKC. PKC activity was assayed by determining the catalytic transfer of ATP to a specific substrate peptide. Survival was determined using the clonogenic assay. Apoptosis was quantitated by counting the number of cells demonstrating apoptosis after staining with acridine-orange/ ethidium bromide. Production of the inducible form of HSP70 was assessed using Western blot.

RESULTS

At 2 microM Ro31-8220, >80% of PKC activity was inhibited in both cell lines, which was associated with no cytotoxicity at 37 degrees C. Basal HSP70 level was approximately 10-fold higher in the TR-4 compared with the RIF-1 cells. Upon TT induction, HSP70 level increased significantly in both cell lines, which was suppressed in the presence of Ro31-8220, but the relative amount of HSP70 remained high in the TR-4 cells. At 24 h, heat-induced apoptosis increased from 4 to 38% in RIF-1 cells in the presence of Ro31-8220, which was associated with a 26% reduction in clonogenic survival after thermotolerant heating. In contrast, <1% of TR-4 cells demonstrated apoptosis even with the highest dose of Ro31-8220, and no effect on survival was observed.

CONCLUSION

Inhibition of PKC activity reduces HSP70 induction, which in turn is associated with promotion of heat-induced apoptosis in RIF-1 cells. However, the survival signals in the TR-4 cells are so strong, that even 80% inhibition of PKC activity has minimal impact on heat-induced apoptosis and survival in this thermoresistant cell line.

Evaluation of the in vivo biodistribution of yttrium-labeled isomers of CHX-DTPA-conjugated monoclonal antibodies

We evaluated the in vivo stability and biodistribution of four isomers (CHX-A', CHA-A", CHX-B' and CHX-B") of 2-(p-isothiocyanatobenzyl)-cyclohexyl-diethylenetriaminepentaaceti c acid (CHX-DTPA), a recently developed backbone-substituted derivative of DTPA.

METHODS

The ligands were conjugated to monoclonal antibody B3, a murine IgG1 kappa, and labeled with 88Y at 55.5-66.6 MBq/mg (1.5-1.8 mCi/mg). Nontumor-bearing nude mice were injected intravenously with 55.5-66.6 kBq (1.5-1.8 microCi) of 88Y-labeled B3 conjugates and with 125I-labeled B3 as an internal control. The mice were then killed at 6, 24, 48, 96 and 168 hr postinjection.

RESULTS

At 168 hr, the concentration of 88Y in processed bone of either CHX-A' [4.6% injected dose (ID)/g] or CHX-A" (4.0%ID/g) was less than that of either the CHX-B' (21.9%ID/g) or B" (12.1%ID/g) ligands. The two ligands CHX-B" and CHX-B' were not acceptable for yttrium labeling of antibody because of their high and progressive bone accumulation. The accumulation of 88Y in bone of CHX-B' was five times greater than that of CHX-A' at 168 hr. The CHX-A" cleared from the circulation slightly faster than CHX-A' without releasing the yttrium and showed the lowest uptake by bone of any of the four isomers. The accumulation in the other normal organs was similar for all four isomers of 88Y-CHX-B3 conjugates.

CONCLUSION

Although the CHX-B" and CHX-B' were not acceptable for labeling with yttrium, the CHX-A' and CHX-A" were suitable, indicating that differences in stereochemistry can greatly influence stability of radionuclide in the chelate.

Epitope blocking: positive and negative effects on the biodistribution of 125I-labeled anti-Tac disulfide-stabilized Fv fragment of two antibodies against different epitopes of the circulating antigen

Prior in vivo studies using the 125I-labeled anti-Tac disulfide-stabilized variable region fragment (125I-anti-Tac dsFv) of monoclonal antibody in the presence of the circulating soluble alpha subunit of the interleukin-2 receptor (sIL-2R alpha) have shown formation of complexes which interfere with biodistribution. In this study we evaluated the effects of preinjecting HuTac and 7G7/B6, two immunoglobulin Gs (IgGs) that recognize different epitopes of sIL-2R alpha, on the biodistribution of 125I-anti-Tac dsFv in mice bearing SP2/Tac tumor xenografts, which produce sIL-2R alpha, or on nude mice injected with 500 ng of sIL-2R alpha. We also evaluated the biodistribution in mice of 125I-labeled sIL-2R alpha injected alone or with HuTac and 7G7/B6. Injection of either HuTac or 7G7/B6 resulted in complexes with the sIL-2R alpha in serum. Injection of HuTac before 125I-anti-Tac dsFv, in SP2/Tac tumor-bearing mice, resulted in faster clearance of the dsFv from the blood (7.6% ID/g at 30 min), compared to 23.2% ID/g for the no-antibody control; preinjection of 7G7/B6 prolonged the retention of 125I-anti-Tac dsFv to 35.3% ID/g, with more complexes in serum. In mice pre-injected with 7G7/B6 the concentration of 125I-anti-Tac dsFv in tumor was lower (5.2 +/- 0.3% ID/g) than in mice preinjected with HuTac (7.9 +/- 1.2% ID/g) or in the control group (5.6 +/- 0.7% ID/g). In conclusion, while both IgGs formed complexes with sIL-2R alpha and prolonged its retention, preinjection of 7G7/B6 was detrimental, because the increased circulating sIL-2R alpha still had the epitope recognized by the dsFv available for binding and neutralized the anti-Tac dsFv upon injection, whereas preinjection of HuTac blocked the epitope.

Biodistribution of 125I-labeled des(1-3) insulin-like growth factor I in tumor-bearing nude mice and its in vitro catabolism

Insulin-like growth factor I (IGF-I) is a potent mitogen for many tumor cell lines, and IGF-I receptors are overexpressed in many tumors. Specific IGF-binding proteins (IGFBPs) modulate the interaction of IGF and its receptors. Consequently, radiolabeled IGF-I has been considered for tumor imaging. In the present study, we investigated the biodistribution of 125I-labeled des(1-3)IGF-I, a truncated analogue of IGF-I, in tumor-bearing nude mice. Additional studies included its catabolism by tumor cells in vitro and its binding to serum IGFBPs in vivo in nude mice. We also compared groups that were and were not injected with unlabeled peptide analogue. Our data showed that 125I-labeled des(1-3)IGF-I catabolized very fast, with a rapid appearance of nonprecipitable iodine, when incubated at 37 degrees C, but it was not catabolized at 4 degrees C incubation. 125I-labeled des(1-3)IGF-I was bound to serum-binding proteins, mainly in a complex with a molecular weight of M(r) 150,000. The uptake of radioactivity in normal tissues decreased quickly with time, particularly in the kidneys. In mice receiving higher doses of des(1-3)IGF-I, the radioactivity in all normal tissues was lower than in the mice with no carrier-added des(1-3)IGF-I, except in the stomach and spleen. These data suggest that 125I-labeled des(1-3)IGF-I is rapidly internalized after binding to the IGF receptor and is rapidly catabolized with release of breakdown products. Lower specific activity of 125I-labeled des(1-3)IGF-I resulted in altered biodistribution, including faster blood clearance and higher tumor uptake, by decreasing the formation of complexes with IGFBPs.

Improved biodistribution of 125I-labeled anti-Tac disulfide-stabilized Fv fragment by blocking its binding to the alpha subunit of the interleukin 2 receptor in the circulation with preinjected humanized anti-Tac IgG

Animal studies using radiolabeled anti-Tac disulfide-stabilized Fv (dsFv) monoclonal antibody have shown formation of complexes in serum with the soluble alpha subunit of the interleukin 2 receptor alpha (sIL-2R alpha). In this study, we improved the targeting of 125I-labeled anti-Tac dsFv to receptor-positive tumors in the presence of circulating receptor by preinjecting unlabeled humanized anti-Tac IgG antibody (HuTac IgG). We used mice bearing SP2/Tac tumor xenografts that express the IL-2R alpha. A positive correlation was seen between tumor size and the concentration of circulating receptor. Tumor-bearing mice were injected with 125I-labeled anti-Tac dsFv (400 ng), either alone or 15 min after injection of HuTac IgG. The 125I-labeled anti-Tac dsFv formed high molecular weight complexes with the sIL-2R alpha. The fraction of the dsFv present in the complexes increased as tumor size increased (greater sIL-2R alpha levels). The fractions of dsFv in the complexes were 9.9- to 11.6-fold higher when sIL-2R alpha was not blocked with preinjected HuTac IgG. The administration of a 12-fold molar excess of HuTac IgG over sIL-2R alpha resulted in >80% of the 125I activity present as the dsFv rather than in the complexes. Furthermore, the biodistribution of 125I-labeled anti-Tac dsFv was improved by blocking its binding to sIL-2R alpha by preinjecting HuTac IgG. Specifically, in the preinjected group, at 15 min postinjection, the 125I-labeled anti-Tac dsFv levels in tumor increased to 10.8% compared to 5.6% injected dose per gram in the non-preinjected group. In summary, our studies showed that preinjection of HuTac IgG can block the formation of complexes of circulating sIL-2R alpha and 125I-labeled anti-Tac dsFv. This blockade is associated with faster blood clearance, higher tumor uptake, and greater tumor:nontumor ratios of the radiolabeled antibody fragment.

[Evaluation of renal function using 99mTc-MAG3: comparison with 123I-OIH and 99mTc-DTPA]

The utility of 99mTc-mercaptoacetyltriglycine (MAG3) with studied clinically. In the renography obtained with 99mTc-MAG3, the abdominal aorta and the common iliac arteries were clearly visualized in the vascular phase. Due to less background activity and high target to background ratio, the quality of 99mTc-MAG3 image was superior to that of 123I-OIH or 99mTc-DTPA image. The parameters on the renogram including Tmax, T2/3, and T1/2 were compared. The correlation of Tmax and T2/3 or T1/2 were not significant between 99mTc-MAG3 and 123I-OIH. Another parameter of C20/Cmax, where C20 and Cmax are renal activities at 20 min after injection and at Tmax respectively, showed an excellent correlation between 99mTc-MAG3 and 123I-OIH. Using C20/Cmax, pattern of renogram can be characterized numerically. Concerning about the relation between C20/Cmax and renogram pattern, standard renogram pattern showed the C20/Cmax value of less than 0.4, while hypofunctioning pattern showed more than 0.5. The correlation coefficient between the renal uptake of 99mTc-MAG3 and 123I-OIH was 0.880 with a correlation plot: "Y = 1.16X-0.043", where X and Y represent renal uptake of 99mTc-MAG3 and 123I-OIH, respectively. It can be concluded that 99mTc-MAG3 is useful renal imaging agent as an alternative to 123I-OIH, in order to evaluate the proximal tubular function and calculate ERPF.

[The utility of quantitative 99mTc-GSA liver scintigraphy in the evaluation of hepatic functional reserve: comparison with 99mTc-PMT and 99mTc-Sn colloid]

Using data from 17 patients with liver cirrhosis and 3 patients with fatty liver, we have compared the utility of 3 hepatic imaging agents in the evaluation of hepatic functional reserve. Evaluated here were 99mTc-galactosyl human serum albumin (GSA) which is a new ligand for hepatic binding protein, 99mTc-N-pyridoxyl-5-methyl tryptophan (PMT) of a hepatobiliary agent, and 99mTc-Sn colloid. In each patient, we performed these 3 imaging studies within a week and also examined hepatic function tests (indocyanine green test, hepaplastin test, choline-esterase, etc). In each imaging study, serial images and dynamic data were obtained after the injection of 99mTc-GSA (185 MBq/3 mg), 99mTc-PMT (185 MBq), or 99mTc-Sn colloid (185 MBq). Using the obtained dynamic data, we analyzed the liver kinetics of the 3 agents based on 1 compartment model with 3 parameters (hepatic clearance, hepatic excretion rate, non-specific volume of distribution). From fitting the liver and heart data to this model, three unknown parameters were determined. Patlak plot was also applied in order to estimate liver uptake rate. Both curve fitting and Patlak plot could determine appropriate parameters in every study. In 99mTc-GSA, a nonlinear 3 compartment model was also applied in order to estimate hepatic blood flow, liver receptor density, and affinity of receptor-GSA binding separately. Using the obtained parameters, we analyzed the correlations between the parameters and the results of hepatic function tests. In all of the parameters, those obtained from 99mTc-GSA imaging showed the most significant statistical correlation with the results of hepatic function tests. From the present results, 99mTc-GSA imaging was concluded to be the best for evaluation of hepatic functional reserve.