[Interim efficacy of a multicenter cohort study for China Net Childhood Lymphoma mature B-cell lymphoma 2017 regimen in the treatment of pediatric High-grade-B cell lymphoma].

Objective: To analyze the mid-term efficacy of the China Net Childhood Lymphoma mature B-cell lymphoma 2017 (CNCL-B-NHL-2017) regimen in treating children with high-grade B-cell lymphoma (HGBL). Methods: Clinical and pathological data of HGBL children aged≤18 years admitted to 16 hospitals of the Chinese Children's Lymphoma Collaborative Group (CNCL) from May 2017 to April 2021 were collected retrospectively. They were divided in to high-grade B-cell lymphoma with double hit/triple hit (HGBL-DH/TH) group and high-grade B-cell lymphoma non-specified (HGBL-NOS) group, according to the 2016 version of the World Health Organization (WHO) Hematopoietic and Lymphoid Tissues Cancer Classification. Both groups of patients were treated with stratified chemotherapy by risk according to the CNCL-B-NHL-2017 scheme. The deadline for follow-up was December 31, 2023. All the patients were examined by chromosome fluorescence in situ hybridization (FISH), and the rearrangement of genes MYC, BCL-2 and BCL-6 was confirmed. The clinical and pathological characteristics of patients at disease onset were analyzed, and the therapeutic effects of patients in different clinical stages and risk groups were compared. Survival analysis was drawn by Kaplan Meier method, the log-rank test was used to compare the differences in the cumulative survival rate between different groups, and multivariate Cox regression model was used to identify the prognostic factors. Results: A total of 62 patients were included, with an onset age [M(Q1, Q3)] of 7 (4, 11) years, including 48 males and 14 females. There were 11 (17.7%) patients in stageⅡ, 33(53.2%)patients in stage Ⅲ and 18(29.1%)patients in stage Ⅳ. FISH testing showed that 4 cases (6.5%) were HGBL-DH and 3 (4.8%) were HGBL-TH. The remaining 55 cases (88.7%) were HGBL-NOS, with 18 cases accompanied by MYC rearrangement. There were 7 cases in the HGBL-DH/TH group and 55 cases in the HGBL-NOS group. Thirteen cases (20.9%) were treated with the B1 regimen, 3 cases (4.8%) with B2 regimen, 37 cases (59.6%) with C1 regimen, and 9 cases (14.7%) with the C2 regimen. Forty-eight cases (77.4%) received rituximab therapy at the same time. Five cases (8.0%) progressed during treatment. The follow-up time [M(Q1, Q3)] was 43.5 (36.1, 53.7) months. The complete remission rate was 91.9% (57/62). The 3 year overall survival rate was 93.5% and event-free survival (EFS) rate was 91.9%. The 3-year overall survival rate in the HGBL-NOS group was higher than that in the HGBL-DH/TH group (96.3% vs 71.4%, P=0.011). The 3-year EFS rate of the HGBL-NOS group was higher than that of the HGBL-DH/TH group (94.5% vs 71.4%, P=0.037). In the HGBL-NOS subgroup, the overall survival rate of children with MYC rearrangement was lower (100% vs 88.9%,P=0.039). Multivariate Cox regression analysis showed that central invasion (HR=6.05, 95%CI: 1.96-38.13, P=0.046) was a risk factor for overall survival. Conclusion: CNCL-B-NHL-2017 regimen shows significant effects in the treatment of pediatric HGBL, with a good prognosis.

[The relationship between male semen parameters and sperm DNA fragment index with the age].

To investigate the relationship between male semen parameters and sperm DNA fragment index with age. Adopt cross-sectional sampling survey design, 3 203 male patients who visited the Department of Reproductive Andrology in the Third Affiliated Hospital of Zhengzhou University from January 2019 to June 2021 were selected as subjects. Age range is 18-57 years, with the median age of 30 years. Through quartile regression analysis, the correlation between age and different male semen parameters and DNA fragment index (DFI) was presented. The study population was divided into ≤30 years old group and >30 years old group, and the correlation between age and semen volume, sperm concentration, total sperm count, progressive motility, total motility, percentage of normal sperm and DFI level were compared and analyzed. The results showed that there were significant differences in progressive motility, total motility and DFI level among different age groups (χ2=-4.608, -4.604, -7.719,P all <0.05), but there was no significant difference in semen volume, sperm concentration, total sperm count and percentage of normal sperm (χ2=-1.712, -1.203, -0.149, -0.175,P all >0.05). In the>30 years old age group, there was a very weak negative correlation between male age and semen volume, progressive motility and total motility (r=-0.137, -0.101 and -0.056, P all <0.05). There was a very weak positive correlation between male age and sperm concentration and sperm DFI level (r=0.061, 0.190, P all <0.05), while there was no correlation between male age and total sperm count and percentage of normal sperm (r=-0.018, -0.016,P all >0.05). In conclusion, with the increase of age, especially after the age of 30, semen volume, progressive motility and total motility decreased, while sperm concentration and DFI level increased, and semen quality decreased.

[A prognostic analysis of cirrhotic esophageal variceal bleeding treated with standardized endoscopic therapy].

Objective: To analyze the clinical effect of standardized endoscopic esophageal variceal ligation alone or in combination with tissue adhesive injection for gastric varices (GV) after the first cirrhotic esophageal variceal bleeding. Methods: A total of 97 patients who underwent a successful endoscopic therapy in our hospital due to the first cirrhotic esophageal variceal bleeding were enrolled, and according to the subsequent therapeutic regimen, they were divided into control group (48 patients) and treatment group (49 patients). The patients in the control group were given conservative treatment alone, and those in the treatment group were given endoscopic therapy regularly. The therapeutic regimen, changes in varices, complications, and death caused by rebleeding were compared between the two groups. The t-test was used for comparison of continuous data between groups, and the chi-square test or Fisher's exact test was used for comparison of categorical data between groups. Results: The treatment group achieved a remission rate of esophageal varices (EV) of 100% and a GV elimination rate of 93.75% after 2-3 times of endoscopic therapy; the EV recurrence, rebleeding, and mortality rates were 2.04%, 0, and 0, respectively, within 1 month, 16.33%, 4.08%, and 0, respectively, within 12 months, and 20.40%, 14.29%, and 4.08%, respectively, within 20 months; the incidence rate of gastric variceal bleeding (GVB) was 0. In the control group, the EV recurrence, rebleeding, and mortality rates were 4.17%, 2.08%, and 2.08%, respectively, within 1 month, 41.67%, 33.33%, and 8.33%, respectively, within 12 months, and 72.92%, 56.25%, and 20.83%, respectively, within 20 months; the incidence rate of GVB was 18.75%. There were significant differences between the two groups in the incidence rate of GVB (χ (2) = 13.605, P = 0.001) and EV long-term recurrence, rebleeding, and mortality rates (12 months: χ (2) = 16.326, P < 0.01; 20 months: χ (2) = 27.144, P < 0.01). Conclusion: Gastroscopy and continuous endoscopic therapy for 2-3 times should be performed regularly after the first cirrhotic esophageal variceal bleeding to alleviate EV, eliminate GV, and reduce rebleeding and mortality rates.

[Mid-term efficacy of China Net Childhood Lymphoma-mature B-cell lymphoma 2017 regimen in the treatment of pediatric Burkitt lymphoma].

Objective: To analyze the clinical characteristics of children with Burkitt lymphoma (BL) and to summarize the mid-term efficacy of China Net Childhood Lymphoma-mature B-cell lymphoma 2017 (CNCL-B-NHL-2017) regimen. Methods: Clinical features of 436 BL patients who were ≤18 years old and treated with the CNCL-B-NHL-2017 regimen from May 2017 to April 2021 were analyzed retrospectively. Clinical characteristics of patients at disease onset were analyzed and the therapeutic effects of patients with different clinical stages and risk groups were compared. Survival analysis was performed by Kaplan-Meier method, and Cox regression was used to identify the prognostic factors. Results: Among 436 patients, there were 368 (84.4%) males and 68 (15.6%) females, the age of disease onset was 6.0 (4.0, 9.0) years old. According to the St. Jude staging system, there were 4 patients (0.9%) with stage Ⅰ, 30 patients (6.9%) with stage Ⅱ, 217 patients (49.8%) with stage Ⅲ, and 185 patients (42.4%) with stage Ⅳ. All patients were stratified into following risk groups: group A (n=1, 0.2%), group B1 (n=46, 10.6%), group B2 (n=19, 4.4%), group C1 (n=285, 65.4%), group C2 (n=85, 19.5%). Sixty-three patients (14.4%) were treated with chemotherapy only and 373 patients (85.6%) were treated with chemotherapy combined with rituximab. Twenty-one patients (4.8%) suffered from progressive disease, 3 patients (0.7%) relapsed, and 13 patients (3.0%) died of treatment-related complications. The follow-up time of all patients was 24.0 (13.0, 35.0) months, the 2-year event free survival (EFS) rate of all patients was (90.9±1.4) %. The 2-year EFS rates of group A, B1, B2, C1 and C2 were 100.0%, 100.0%, (94.7±5.1) %, (90.7±1.7) % and (85.9±4.0) %, respectively. The 2-year EFS rates was higher in group A, B1, and B2 than those in group C1 (χ2=4.16, P=0.041) and group C2 (χ2=7.21, P=0.007). The 2-year EFS rates of the patients treated with chemotherapy alone and those treated with chemotherapy combined with rituximab were (79.3±5.1)% and (92.9±1.4)% (χ2=14.23, P<0.001) respectively. Multivariate analysis showed that stage Ⅳ (including leukemia stage), serum lactate dehydrogenase (LDH)>4-fold normal value, and with residual tumor in the mid-term evaluation were risk factors for poor prognosis (HR=1.38,1.23,8.52,95%CI 1.05-1.82,1.05-1.43,3.96-18.30). Conclusions: The CNCL-B-NHL-2017 regimen show significant effect in the treatment of pediatric BL. The combination of rituximab improve the efficacy further.

An improved nomogram including elastography to predict the histological upgrade of ductal carcinoma in situ of the breast.

OBJECTIVE: About 30% of the breast's ductal carcinoma in situ (DCIS) will be histological upstate according to the postoperative pathology. Sentinel lymph node biopsy (SLNB) is currently recommended on most DCIS excision in order to potentially avoid secondary surgery, which is apparently over-treated for most patients with DCIS. Hence, the decision to perform SLNB before DCIS excision remains controversial. The aim of this study is to establish an improved nomogram including elastography for predicting the risk of the histological upgrade of DCIS preoperatively. PATIENTS AND METHODS: The medical records of 147 patients who were preoperatively diagnosed with DCIS and underwent breast surgery were retrospectively reviewed. They were divided into DCIS group (n=99) and DCIS with invasive components (DCIS-IC) group (n=48) according to the postoperative pathology results. The clinicopathologic and multimode ultrasonic records were analyzed and used to develop the nomogram. The difference in performance between the nomogram with and without acoustic radiation force impulse (ARFI) elastography was compared in this study. RESULTS: Patients with high-grade lesions (OR = 4.762, p = 0.032), positive human epidemal growth factor receptor 2 (HER-2) expression (OR = 3.560, p = 0.007), comedo type of DCIS (OR: 3.163, p = 0.041), larger lesion size (OR = 3.253, p = 0.002), and higher mean SWV value (SWVmean) (OR: 5.083, p < 0.001) were found to be independent factors associated with the histologic upgrade. The discrimination of the nomogram (0.896), including the 5 independent predictors (ARFI elastography included), was higher than that without ARFI elastography (0.788). It could be utilized to predict the probability of the histologic upgrade of DCIS. CONCLUSIONS: The developed nomogram incorporating ARFI elastography is expected to predict the risk of the histologic upgrade of DCIS preoperatively and to provide a reference for the decision making for SLNB. It showed improved performance owing to the elastography.

Clinical pharmacokinetics of tacrolimus after the first oral administration in combination with mycophenolate mofetil and prednisone in Chinese renal transplant recipients.

INTRODUCTION: Data on tacrolimus pharmacokinetics in combination with mycophenolate mofetil and prednisone are scarce in Chinese renal transplantation recipients. The purpose of this study was to detect interpatient pharmacokinetic variability of tacrolimus and to assess the predictability of individual tacrolimus concentrations at various times for the area under the curve (AUC) seeking to find the best sampling time for an abbreviated AUC to predict the total body exposure of tacrolimus after the first oral dose in Chinese renal transplantation recipients. METHODS: Sixteen primary kidney transplant recipients were treated with methylprednisolone and antilymphocyte globulin for 3 days. The first tacrolimus oral dose (0.075 mg/kg) was given at day 3 posttransplant. Mycophenolate mofetil and prednisone were administered orally posttransplant. Blood samples were obtained at 0.5, 1.0, 1.5, 2.0, 3.0, 5.0, 8.0, and 12.0 hours after taking the first oral dose. Tacrolimus blood concentrations were measured by ELISA. Twelve-hour AUC (AUC12) for each patient was calculated using the linear trapezoid rule. Associations between the blood concentration at each sampling time point and the AUC12 were evaluated by Pearson correlation coefficients. Abbreviated sampling equations were derived by multiple, stepwise regression analyses performed using AUC12 as the dependent variables. The variance in the strength of association between predicted AUC (AUC(P)) and AUC12 was reflected by linear regression coefficients of multiple determinations. RESULTS: In 16 patients, AUC12 values were within the range of 44.40 ng x h/mL to 158.01 ng x h/mL (mean = 92.23 +/- 34.97 ng x h/mL). The area of the maximum AUC12 was almost fourfold higher than that of the minimum AUC12. C12 significantly correlated with AUC(12) after the first tarcrolimus oral dose (r = .846, P < .001). C5, C8, and C3 showed better correlations: r = .924, .924, and .911, respectively. From stepwise multiple regression, C5 seemed to be the best predictor of total body exposure to tacrolimus (r = .92, r2 = .85). Alternatively, the concentrations at 5 and 1.5 hours or 5, 1.5, and 3 hours as an abbreviated AUC were as good as a full pharmacokinetic study (r = .97, r2 = .94, and r = .99, r2 = .99, respectively). CONCLUSIONS: Tacrolimus AUC12 show remarkable interindividual variations after the first oral dose in combination with mycophenolate mofetil and prednisone in Chinese renal transplant recipients. Although C12 is a good predictor of efficacy, C5 might be the best predictor of the first AUC12. A two-point sampling method using C5 and C1.5 or three-point sampling method using C5, C1.5, and C3 might be the best abbreviated AUC for a cost-effective tacrolimus monitoring strategy.

Properties of uracil phosphoribosyltransferase from Giardia intestinalis.

Incorporation of pyrimidine ribonucleotides in Giardia intestinalis occurs via uracil phosphoribosyltransferase (UPRTase). The enzyme was purified over 1000-fold to apparent homogeneity from parasite extracts, using Fast Protein Liquid Chromatography, namely Mono Q anion exchange, Mono P chromatofocusing and Superose 12 chromatography. The specific activity of the purified enzyme was 3100 nmol min-1 mg protein-1. The enzyme was found to be a dimer of mol. wt. 76,000. Kinetic analysis, including initial velocity and product inhibition studies, indicated that it obeyed a rapid-random equilibrium mechanism. GTP and dGTP caused a dramatic increase in the activity of the enzyme, though there was no effect on the Michaelis constants. All other nucleotides tested were without effect or were inhibitory. The effect of GTP is similar to that observed for UPRTase from E. coli but not from other eukaryotes.

[Production of transgenic lamb integrated with modified human anti-trypsin gene].

This experiment is to produce the human mAAT(modified anti-trypsin) which cures the emphysema specifically through mammalian galactophore of transgenic goat. 56 goats were selected as donor for superovulation by FSF + LH microinjection in this experiment. The pronucleic embryos were injected with human mAAT gene after fertilization in vivo, and transferred to the donors or receptors directly. The superovulation was better in March and May than in December with the number of ovulation of 19.50, 21.70 and 16.06, and number of fertilized embryos of 4.31, 6.48 and 3.57 per-animal respectively. The pregnant rates were 18.18% and 25% respectively after transferred to donors and receptors with natural estrus. The donors also can be used as the embryo receptor with no remarkable decrease of pregnant rate. 29 lamb were labored. 4 positive transgenic lamb were checked by PCR, PCR-Southern and Southern analysis. The integrated efficiency of foreign DNA was 13.79% with microinjection of high copy number of foreign DNA fragment.

[A facile synthesis of adenosine 3', 5'-cyclic methylphosphonate and methylphosphonothioate].

A facile synthesis of adenosine 3', 5'-cyclic methylphosphonate (1) and 3', 5'-cyclic methylphosphonothioate (2) was accomplished by treatment of 2'-protected adenosine with O,O-bis (1-benzotriazolyl) methylphosphonate or O,O-bis (1-benzotriazolyl) methylphosphonothioate under mild conditions, respectively. The ability of the compounds to inhibit DNA synthesis in mice hepatoma was tested. A pair of diasteromers of 2'-protected (1) was separated and the configuration at the phosphorus atom was identified.

Abnormal endothelial function in ED patients with normal nocturnal penile tumescence and rigidity: is it the role of psychogenic factors?

Underlying endothelial dysfunction (EnD) may present in the early stage of ED or psychogenic ED. We retrospectively evaluated 191 ED patients with effective nocturnal penile tumescence and rigidity (NPTR) recording, including detailed medical and psychosexual history, International Index of Erectile Function-5 and vascular parameter. All patients were allocated into psychogenic and organic groups according to the NPTR test. Brachial artery flow-mediated dilation (FMD) was used to diagnose EnD, and ED patients were classified into two groups: non-EnD (FMD10) and EnD (FMD<10). General and vascular parameters were compared between psychogenic and organic groups, and non-EnD and EnD groups with ED were compared in terms of NPTR parameters. In all, 48.7% and 51.3% patients were diagnosed as psychogenic and organic ED, respectively. 73.1% of the psychogenic patients had EnD and 39.8% organic patients had normal endothelial function. In all parameters, only the FMD value showed significant difference between psychogenic and organic ED groups (8.26±2.57 vs 9.16±2.76, P=0.020). No statistical difference was founded in NPTR parameters between non-EnD and EnD groups (P>0.05). In conclusion, NPTR cannot effectively identify the underlying vasculogenic ED from psychogenic ED. Psychogenic causes may cause or aggravate EnD in these ED patients with normal NPTR.

Aberrant gene expression in deceased transgenic cloned calves.

Several transgenic cloned species have been obtained; however, the efficiency of transgenic cloning remains very low, even lower than cloning. Many experiments have demonstrated abnormal growth and development, and inappropriate gene expression in cloned animals. In this study, we examined the expression of 19 development-related genes in lungs of three normal controls and three aberrant transgenic cloned calves. Results showed in transgenic cloned calves, 84.2% genes had decreased expression levels, however, 5.3% genes had increased levels. This study suggests transgenic cloning and the aberrant expression would cause abnormal growth and development in transgenic cloned calves. To our knowledge, this is the first time that gene expression was examined in transgenic cloned cattle. These findings may have some implications in understanding the low efficiency of the transgenic cloning.

Improved parthenogenetic development of vitrified-warmed bovine oocytes activated with 9% ethanol plus 6-DMAP.

The objective was to compare various activation protocols on developmental potential of vitrified bovine oocytes. Bovine oocytes matured in vitro for 23 h were vitrified with EDFSF30 in open pulled straws. After warming, they were cultured in vitro for 1h, followed by parthenogenetic activation. Vitrified-warmed oocytes had a morphologically normal rate similar to that of controls (nonvitrified oocytes cultured in vitro for 24h; 98.6% vs. 100%, P>0.05). When vitrified-warmed oocytes were first activated with 7% ethanol for 5 min and then incubated in 6-dimethylaminopurin (6-DMAP) for 4h, cleavage and blastocyst rates were 41.2% and 23.2%, respectively, which were lower than those of controls (77.5% and 42.0%, P < 0.05). Subsequently, we varied the ethanol concentration to increase the effectiveness of parthenogenetic activation. When either 5%, 6%, 7%, 8%, 9%, 10%, or 11% ethanol alone (for 5 min) or in combination with 6-DMAP (4h) was used to activate vitrified-warmed oocytes, cleavage rates ranged from 22.3% to 61.1% and blastocyst rates ranged from 1.1% to 30.6%. These rates were optimized when oocytes were treated with 9% ethanol plus 6-DMAP; this was verified in experiments evaluating other activation protocols with 9% ethanol, calcium ionophore A23187, or ionomycin alone, or in combination with DMAP or cycloheximide (CHX). In conclusion, the oocyte activation protocol affected developmental capacity of vitrified bovine oocytes; 9% ethanol (5 min) followed by 6-DMAP (4h) promoted optimal parthenogenetic activation.

Hypotonic activation of volume-sensitive outwardly rectifying anion channels (VSOACs) requires coordinated remodeling of subcortical and perinuclear actin filaments.

Cell volume regulation requires activation of volume-sensitive outwardly rectifying anion channels (VSOACs). The actin cytoskeleton may participate in the activation of VSOACs but the roles of the two major actin pools remain undefined. We hypothesized that structural reorganization of both subcortical and perinuclear actin filaments (F-actin) contributes to the hypotonic activation of VSOACs. Hypotonic stress of pulmonary artery smooth muscle cells (PASMCs) was associated with reorganization of both peripheral and perinuclear F-actin, and with activation of VSOACs. Preincubation with cytochalasin D caused prominent dissociation of perinuclear, but not of subcortical F-actin. Cytochalasin D failed to induce isotonic activation and delayed the hypotonic activation of VSOACs. F-actin stabilization by phalloidin delayed both the hypotonic stress-induced dissociation of membrane-associated actin filaments and the activation kinetics of VSOACs. PKCepsilon, which was proposed to phosphorylate and inhibit VSOACs, colocalized primarily with F-actin and the net kinase activity remained unchanged during hypotonic cell swelling. In conclusion, normal hypotonic activation of VSOACs requires disruption of peripheral F-actin but intact perinuclear F-actin; interference with this pattern of actin reorganization delays the activation kinetics of VSOACs. The cell swelling-induced peripheral actin dissociation may underlie the observed translocation of PKCepsilon, which leads to a net decrease of PKCepsilon inhibitory activity in submembranous sites. Thus, reorganization of actin and PKCepsilon may establish conditions for mechano- and/or signal transduction-mediated activation of VSOACs.

Lupus antibody bivalency is required to enhance prothrombin binding to phospholipid.

Lupus anticoagulants (LA) are a family of autoantibodies that are associated with in vitro anticoagulant activity but a strong predisposition to in vivo thrombosis. They are directed against plasma phospholipid-binding proteins including prothrombin. We have proposed that LA propagates coagulation in flowing blood by facilitating prothrombin interaction with the damaged blood vessel wall. A murine monoclonal anti-prothrombin Ab and three of three LA IgGs enhanced prothrombin binding to 75:25 phosphatidyl choline:phosphatidyl serine vesicles measured by either ultracentrifugation or right-angle light scattering. The assembly of prothrombin and LA IgG on phospholipid vesicles was estimated by surface plasmon resonance. The on rates for prothrombin and LA IgG were approximately the same as the on rate for prothrombin alone. In contrast, the off rates for prothrombin and LA IgG were 2- to 3-fold slower than the off rate for prothrombin. LA IgG bivalency was required for enhanced prothrombin binding to phospholipid vesicles, as Fab of the LA IgGs did not influence prothrombin binding at concentrations up to 40 microM. Modeling of the interactions of prothrombin, LA IgG and phospholipid vesicles indicated that augmentation of prothrombin binding to phospholipid vesicles by LA IgG could be accounted for by the bivalency of the LA IgG and the elevated microenvironmental concentration of prothrombin on the surface of phospholipid vesicles.

Microheterogeneity of beta-2 glycoprotein I: implications for binding to anionic phospholipids.

Considerable interest is currently focused on the interactions of beta-2 glycoprotein I (beta2GPI) and anti-phospholipid antibodies with anionic phospholipids in an attempt to understand the association between these antibodies and clinical diseases such as thrombosis. The interactions of beta2GPI and anionic phospholipids have only been characterized partially, and the physiological role of this glycoprotein remains uncertain. In this study we have explored in detail the physical and phospholipid-binding characteristics of a number of beta2GPI preparations. We have found (i) that perchloric acid-purification methods are damaging to beta2GPI during purification, (ii) that the dissociation constants of the various preparations for phosphatidylserine vary between 0. 1-2 microM and are considerably weaker than previously reported, (iii) that considerable differences in affinity of the various beta2GPI preparations for anionic phospholipids are obtained when comparing anionic phospholipids immobilized to a solid-phase versus phospholipid assembled in unilamellar vesicles, (iv) that the integrity of the fifth domain of beta2GPI is important for binding immobilized anionic phospholipid but not especially important in binding vesicular anionic phospholipid, and (v) that beta2GPI preparations with differing isoelectric species content bind anionic phospholipids differently, suggesting that varying glycosylation and/or protein polymorphisms impact upon phospholipid binding. These results highlight the importance of assessing the determinants of the interaction of beta2GPI with anionic phospholipids assembled in unilamellar vesicles.

Soluble low density lipoprotein receptor-related protein (LRP) circulates in human plasma.

Our studies have identified a soluble molecule in normal human plasma and serum with the characteristics of the alpha-chain of the low density lipoprotein receptor-related protein (LRP). LRP is a large multifunctional receptor mediating the clearance of diverse ligands, including selected lipoproteins, various protease inhibitor complexes, and thrombospondin. A soluble molecule (sLRP) has been isolated from plasma using an affinity matrix coupled with methylamine-activated alpha2-macroglobulin, the ligand uniquely recognized by LRP, and eluted with EDTA. This eluate contains a protein that co-migrates on SDS-polyacrylamide gel electrophoresis with authentic human placental LRP alpha-chain, is recognized by anti-LRP alpha-chain monoclonal antibodies, and binds the 39-kDa receptor-associated protein (RAP) and tissue plasminogen activator-inhibitor complexes. A similar RAP-binding molecule was detected in medium conditioned for 24 h by primary cultures of rat hepatocytes, suggesting that the liver may be the in vivo source of sLRP. In contrast, immunoprecipitation experiments failed to detect the production of sLRP by cultured HepG2 hepatoma and primary human fibroblast cells. Addition of a soluble form of LRP to cultured HepG2 cells resulted in a significant inhibition of capacity of these cells to degrade tPA, a process that has been demonstrated to be mediated by cell surface LRP. Preliminary data indicate that the concentration of sLRP is altered in the plasma of patients with liver disease. Increased levels of sLRP may antagonize the clearance of ligands by cell bound LRP perturbing diverse processes including lipid metabolism, cell migration and extracellular proteinase activity.