Simplified urethral score system for predicting complex anterior urethroplasty.

OBJECTIVE: To assess U-score individual values as urethral complex surgery predictors. METHODS: Cross-sectional study including patients who received anterior urethroplasty from 2011 to 2019. U-score (etiology (1-2 points), number of strictures (1-2 points), anatomic location (1-2 points) and length (1-3 points)) was measured individually and globally. Surgical complexity was defined as low (anastomotic, buccal mucosal graft, and augmented anterior urethroplasty), and high complexity (double buccal mucosal graft, flap, and graft/flap combination). U-score components were included as complex surgery predictor and as main variable with individual probability values estimations and comparisons. Risk complex surgery probability groups were established. RESULTS: 654 patients were included. Mean age was 57.2 years. Low complexity surgery was performed in 464 patients (259 anastomotic, 144 graft, 61 augmented anterior urethroplasty) and high complexity was done in 190 (53 double buccal mucosa graft, 27 flap, 110 graft/flap comb.). In multivariate analysis length, number of strictures and location were predictors of complexity. Introducing U-Score as only variable in univariate model predicted an OR 8.52 (95%CI 6.1-11). Simplified U-score grouping set obtained by complex probability was: low risk (4-5 points), medium risk (6 points) and high risk of complexity (7-9 points) Predicted risk of complex surgery probability (95%CI) for low, median and high risk group were 1.6 (0-2.9), 19.1 (13.8-25.9) and 77.9 (61.6-88.7), respectively. CONCLUSIONS: U-score can be used as a tool to predict complex urethral surgery. We present a simplified U-score risk tool to assess individual complex anterior urethroplasty probability.

Safety and efficacy of urethroplasty based on age groups.

OBJECTIVE: To analyze the results and complications after urethroplasty based on patient age groups. As secondary objective, we analyzed the impact of operative complexity on each age group. MATERIAL AND METHODS: This is a retrospective cohort study that include male patients who underwent urethroplasty between January 2011 and December 2018. Data was obtained from the patients' electronic health records. Patients were grouped as follows: <60 years, 60-79 years and >80 years. Variables evaluated were history, comorbidities, previous surgeries and operative complexity. Restenosis-free survival and complications presented in each group were determined according to the Clavien-Dindo classification system. The SPSS® program was used for statistical analysis. RESULTS: A total of 783 patients were included, and the mean follow-up was 19 months. The estimated 2-year restenosis-free survival in the population under 60, 60-79 and over 80 years was 87, 87 and 93.9% (IC 95%), respectively. Univariate analysis showed that the age group was not a predictor of restenosis. Complex surgery is the only predictor of recurrence, increasing the risk by 60% (HR 1.64, 95% CI 1.05-2.56, p = 0.029). There was an overall complication rate of 30.8%, and 62% of these were Clavien ≤ II. We found no association between the frequency of complications and age. CONCLUSIONS: Urethroplasty is safe and effective regardless of age group. There are no statistically significant differences in outcomes and complications shown by the age group comparison. There were no significant differences when analyzing the impact of complex surgeries among the different age groups. The data indicate that age alone should not be taken as an absolute exclusion criterion for patients needing urethral reconstruction.

Safety and efficacy of urethroplasty based on age groups. / Seguridad y eficacia de la uretroplastia según grupos etarios.

OBJECTIVE: To analyze the results and complications after urethroplasty based on patient age groups. As secondary objective, we analyzed the impact of operative complexity on each age group. MATERIAL AND METHODS: This is a retrospective cohort study that include male patients who underwent urethroplasty between January 2011 and December 2018. Data was obtained from the patients' electronic health records. Patients were grouped as follows: < 60 years, 60-79 years and > 80 years. Variables evaluated were history, comorbidities, previous surgeries and operative complexity. Restenosis-free survival and complications presented in each group were determined according to the Clavien-Dindo classification system. The SPSS® program was used for statistical analysis. RESULTS: A total of 783 patients were included, and the mean follow-up was 19 months. The estimated 2-year restenosis-free survival in the population under 60, 60-79 and over 80 years was 87, 87 and 93.9% (IC 95%), respectively. Univariate analysis showed that the age group was not a predictor of restenosis. Complex surgery is the only predictor of recurrence, increasing the risk by 60% (HR 1.64, 95% CI 1.05-2.56, p = 0.029). There was an overall complication rate of 30.8%, and 62% of these were Clavien ≤ II. We found no association between the frequency of complications and age. CONCLUSIONS: Urethroplasty is safe and effective regardless of age group. There are no statistically significant differences in outcomes and complications shown by the age group comparison. There were no significant differences when analyzing the impact of complex surgeries among the different age groups. The data indicate that age alone should not be taken as an absolute exclusion criterion for patients needing urethral reconstruction.

Postoperative urinary extravasation does not impact anterior urethroplasty surgical outcomes: a Latin American large cohort study.

OBJECTIVE: To determine the prevalence of postoperative urinary extravasation (POUE) following anterior urethroplasty, to analyze factors associated with its occurrence, and to study the impact of POUE on surgical success. MATERIALS AND METHODS: Retrospective cohort study including all male patients who have undergone a urethroplasty at our center between 2011 and 2018. Subjects with posterior location stricture, those who did not undergo routine radiographic follow-up, or patients with inadequate follow-up were excluded. Urinary extravasation was defined as presence of evident contrast extravasation on the postoperative voiding cystourethrogram (VCUG). Impact was determined as "need-for-reoperation". Uni- and multivariate analysis were performed to determine clinical and demographic variables associated with occurrence of extravasation and postoperative stricture. RESULTS: A total of 783 men underwent a urethroplasty and 630 fulfilled inclusion criteria. Urinary extravasation prevalence was 12.2%, and there was a "need-for-reoperation" in 1.1% of cases. On uni- and multivariate analysis, greatest stricture length (HR: 1.07 (1-1.2), p = 0.05) and penile urethral location (HR: 2.29 (1.1-4.6), p = 0.021) showed to be POUE predictors. POUE did not show to be a risk factor for postoperative stricture (HR: 1.57, 95% CI (0.8-3), p = 0.173). However, reoperation group  showed to be a risk factor (HR: 6.6, 95% CI 1.4-31, p = 0.019). CONCLUSIONS: Prevalence of POUE was 12.2%. Stricture length and penile urethral strictures were POUE predictors. POUE occurrence with successful conservative management did not appear to have impact on urethroplasty outcomes as it did not predict re-stricture. POUE was reoperation cause in 1.1% of total cases.

Synthesis and application of a N-1' fluorescent biotinyl derivative inducing the specific carboxy-terminal dual labeling of a novel RhoB-selective scFv.

The fluorescent site-specific labeling of protein would provide a new, easy-to-use alternative to biochemical and immunochemical methods. We used an intein-mediated strategy for covalent labeling of the carboxy-terminal amino acid of a RhoB-selective scFv previously isolated from a phage display library (a human synthetic V(H) + V(L) scFv phage library). The scFv fused to the Mxe intein was produced in E. coli and purified and was then labeled with a newly synthesized fluorescent biotinyl cysteine derivative capable of inducing scFv-Mxe intein splicing. In this study, we investigated the splicing and labeling properties of various amino acids in the hinge domain between scFv and Mxe under thiol activation. In this dual labeling system, the fluorescein is used for antibody detection and biotin is used for purification, resulting in a high specific activity for fluorescence. We then checked that the purified biotinylated fluorescent scFv retained its selectivity for RhoB without modification of its affinity.

Impaired B-cell reconstitution in lymphoma patients undergoing allogeneic HSCT: an effect of pretreatment with rituximab?

Allogeneic hematopoietic SCT (HSCT) is increasingly considered an option in refractory or relapsing lymphoma. Today, most patients with B-cell lymphoma are treated with the monoclonal anti-CD20 antibody rituximab before HSCT. We hypothesized that prior therapy with rituximab might alter immune reconstitution after allogeneic transplantation due to in vivo depletion of B cells at the time of graft infusion. We studied B-cell immune reconstitution in 12 patients with lymphoma receiving rituximab 1-12 months before HSCT. Compared to an age- and sex-matched population of patients transplanted for myeloid malignancies, lymphoma patients with rituximab pretreatment showed significantly reduced B-cell counts at time of HSCT at +3, +6 and +12 months; B-cell counts reached values comparable to controls only 24 months after HSCT. In parallel, levels of immunoglobulins were markedly reduced for up to 2 years post transplant in patients with prior rituximab treatment. Two patients suffered from severe late bacterial infections to which the impaired humoral immunity may have contributed. In contrast, T- and NK-cell reconstitution was not different compared to control patients.In conclusion, B-cell reconstitution can be significantly delayed in allogeneic HSCT recipients with prior rituximab treatment. Rituximab appears to have clinical consequences beyond the immediate early post-transplant period.

Pelvic exenteration for gynecologic malignancies: Postoperative complications and oncologic outcomes. / Exenteración pélvica para neoplasias ginecológicas: Complicaciones postoperatorias y resultados oncológicos.

INTRODUCTION AND OBJECTIVE: To evaluate complications, morbidity and oncologic outcomes of pelvic exenteration as treatment for gynecologic malignancies. MATERIALS AND METHODS: Between 2008 and 2015, a total of 35 patients underwent pelvic exenteration, due to recurrence of gynecological cancer. Surgical outcomes, early and late postoperative complications, and recurrence/survival outcomes were assessed. RESULTS: Mean patient age was 53.8 years. Anterior exenteration was done in 20 patients, while 15 were total exenterations. Ileal conduit was done in 24 patients, while 8 received a neobladder and 3 a cutaneous ureterostomy. Postoperative complications were divided in 2groups, early (<30 days) and late complications (>30 days). A total of 25 patients (71.4%) had one or more early complications; 16 (45.7%) had fever due to a urinary tract infection, pyelonephritis or intra-abdominal collection; 2 (5.7%) developed a vesicovaginal fistula; 4 (11.4%) a rectovaginal fistula; 3 (8.5%) acute kidney failure and one (2.85%) uronephrosis. Regarding to late complications, 8patients (22.8%) had fever. Six (17%) presented with uronephrosis, and 5 (14.2%) with ureteral-pouch stricture. Five patients (14.2%) had acute renal insufficiency, 3 (8,6%) rectovaginal fistula and one (2.85%) urinary fistula. Mean follow up time was 20.3 month (2-60). A total of 22patients (62.8%) were free of disease. Another 13 (37.1%) patients relapsed. Only 4 (11.4%) patients died after pelvic exenteration due to underlying disease. CONCLUSION: Pelvic exenteration has a high rate of complications and morbidity, but can be the last curative opportunity in patients with recurrent or persistent gynecologic malignancies. This procedure should be performed by multidisciplinary, experienced teams in a tertiary medical center.

Safety of sofosbuvir-based regimens after liver transplantation: longitudinal assessment of renal function in the prospective ANRS CO23 CUPILT study.

BACKGROUND: In liver transplant recipients with hepatitis C virus recurrence, there is concern about renal safety of sofosbuvir-based regimens. Changes in serum creatinine or in the estimated glomerular filtration rate (eGFR) under treatment are used to look for possible renal toxicity. However, serum creatinine and eGFR are highly variable. AIM: To analyse renal function trajectory with numerous assays of serum creatinine over a long period of time. METHODS: In a multicentre cohort of 139 patients, the eGFR was obtained from serum creatinine using the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation. Slopes of eGFR were defined as a change in eGFR during a period divided by time. Pre-treatment, on-treatment and post-treatment periods were 9 months, 3-9 months and 4.5 months. Interactions between eGFR slopes and the pre-treatment eGFR, use of ribavirin or mycophenolate mofetil, and stage of fibrosis were addressed. On-treatment eGFR slopes were separated in tertiles. Pre- and post-treatment eGFR slopes were compared globally and according to tertiles. RESULTS: The post-treatment eGFR slope was significantly better than pre-treatment eGFR slope (+0.18 (IQR -0.76 to +1.32) vs -0.11 (IQR -1.01 to +0.73) mL/min/1.73 m2 /month, P = 0.03) independently of the pre-treatment eGFR (P = 0.99), ribavirin administration (P = 0.26), mycophenolate mofetil administration (P = 0.51) and stage of fibrosis (F3 and F4 vs lower stages, P = 0.18; F4 vs lower stages, P = 0.08; F4 Child-Pugh B and C vs lower stages, P = 0.38). Tertiles of on-treatment eGFR slopes were -1.71 (IQR -2.54 to -1.48), -0.78 (IQR -1.03 to -0.36) and +0.75 (IQR +0.28 to +1.47) mL/min/1.73 m2 /month. Pre- and post-treatment eGFR slopes were not significantly different according to tertiles (respectively, P = 0.34, 0.08, 0.73). CONCLUSION: The eGFR varies during treatment and gives a confusing picture of the renal safety of sofosbuvir-based regimens. In contrast, longitudinal assessment of the eGFR shows a rising trajectory over longer time, meaning that these therapies are safe for the kidneys in our cohort of liver transplant recipients.

Farnesylated RhoB inhibits radiation-induced mitotic cell death and controls radiation-induced centrosome overduplication.

Our previous results demonstrated that expressing the GTPase ras homolog gene family, member B (RhoB) in radiosensitive NIH3T3 cells increases their survival following 2 Gy irradiation (SF2). We have first demonstrated here that RhoB expression inhibits radiation-induced mitotic cell death. RhoB is present in both a farnesylated and a geranylgeranylated form in vivo. By expressing RhoB mutants encoding for farnesylated (RhoB-F cells), geranylgeranylated or the CAAX deleted form of RhoB, we have then shown that only RhoB-F expression was able to increase the SF2 value by reducing the sensitivity of these cells to radiation-induced mitotic cell death. Moreover, RhoB-F cells showed an increased G2 arrest and an inhibition of centrosome overduplication following irradiation mediated by the Rho-kinase, strongly suggesting that RhoB-F may control centrosome overduplication during the G2 arrest after irradiation. Overall, our results for the first time clearly implicate farnesylated RhoB as a crucial protein in mediating cellular resistance to radiation-induced nonapoptotic cell death.

Geranylgeranyl transferase inhibition stimulates anti-melanoma immune response through MHC Class I and costimulatory molecule expression.

Defective antitumor immune responses are frequent consequences of defects in the expression of major histocompatibility complex (MHC) class I and costimulatory molecules. We demonstrated that statins, inhibitors of HMGCoA reductase, enhance mIFN-gamma induced expression of MHC class I antigens on murine B16F10 melanoma. GGTI-298, a geranylgeranyl transferase I inhibitor, but not FTI-277, a farnesyl transferase inhibitor, mimics this effect of statins. This effect is related to peptide transporter protein TAP1 up-regulation. Simultaneously, GGTI-298 induces the expression of CD80 and CD86 costimulatory molecules. C3 exoenzyme, which selectively inactivates Rho proteins, phenocopies the effects of GGTI-298, indicating a role for Rho proteins in these events. Furthermore, the treatment of B16F10 cells with GGTI-298 or C3 exoenzyme associated with mIFN-gamma induces in vivo tumor growth slowing down in immunocompetent but not in nu/nu syngeneic mice. Both in vivo injections and in vitro restimulation of splenocytes with GGTI-298- and mIFN-gamma-treated B16F10 cells induces an enhancement of specific CD8 T lymphocytes labeled by TRP-2/H-2K(b) tetramers. Finally, these effects are not limited to mouse models since they were also reproduced in two human melanoma cell lines. These observations indicate that protein geranylgeranylation as well as Rho protein are critical for costimulatory and IFN-gamma-dependent MHC class I molecule expression in melanoma.

GGTI-298 induces G0-G1 block and apoptosis whereas FTI-277 causes G2-M enrichment in A549 cells.

The mechanism by which the geranylgeranyltransferase I inhibitor GGTI-298 and the farnesyltransferase inhibitor FTI-277 inhibit human tumor growth is not known. Herein, we demonstrate that in the human lung adenocarcinoma A549 cells, GGTI-298 induced a G1-G0 block whereas FTI-277 induced an enrichment in the G2-M phase of the cell cycle. Although FTI-277, GGTI-298, and compactin inhibited A549 cell growth, only GGTI-298 and compactin induced apoptosis as demonstrated by four criteria: 4',6-diamidine-2-phenylindoledihydrochloride staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, DNA fragmentation assay, and flow cytometry. Furthermore, the involvement of geranylgeranylated proteins in apoptotic pathways was confirmed by demonstrating that geranylgeraniol was able to block the ability of compactin to induce apoptosis. These results suggest that protein geranylgeranylation is critical for the control of programmed cell death and that, in A549 cells, farnesylated and geranylgeranylated proteins are involved in G2-M and G0-G1, respectively.

Radioresistance induced by the high molecular forms of the basic fibroblast growth factor is associated with an increased G2 delay and a hyperphosphorylation of p34CDC2 in HeLa cells.

The basic fibroblast growth factor-(bFGF) mediated signal transduction pathway has been implicated in cellular resistance to ionizing radiation. bFGF is synthesized from the same mRNA in four isoforms resulting from alternative initiations of translation at three CUG start codons (24, 21.5, and 21 kDa) and one AUG start codon (18 kDa). We analyzed the implication of high- and low-molecular forms of bFGF in radioresistance acquisition. For this, we transfected HeLa cells with retroviral vector containing either the CUG-initiated 24-kDa molecular form (HeLa 3A cells), the AUG-initiated 18-kDa molecular bFGF form (HeLa 5A cells), or the vector alone (HeLa PINA cells). A significantly increased radioresistance was obtained only in HeLa 3A cells (Dq = 810 +/- 24 cGy) compared with wild-type cells (Dq = 253 +/- 49 cGy) or HeLa PINA cells (Dq = 256 +/- 29 cGy; P < 0.001). This radioprotective effect was independent of an inhibition of radiation-induced apoptosis but related to an increased G2 duration after irradiation and to an hyperphosphorylation of p34cdc2 kinase. Knowledge of the high-molecular bFGF form-induced radioresistance pathway could offer novel targets for decreasing the radioresistance phenotype of tumors expressing high amounts of bFGF, such as glioblastoma.

Low-density lipoprotein for delivery of an acrylophenone antineoplastic molecule into malignant cells.

In vitro and in vivo data have indicated that tumor cells actively internalize the low-density lipoprotein (LDL) from the circulation. A family of 2-(aminomethyl) acrylophenones (AMA) possesses an in vitro antileukemic activity but is devoid of any in vivo antineoplastic activity, because the compounds are actively captured by proteins in solution in the blood. In order to achieve a selective delivery of these drugs via the LDL pathway, we have incorporated an AMA drug, 2-morpholinomethyl-2',3',4'- trimethoxy acrylophenone hydrochloride (ILE) into LDL particles. ILE spontaneously associated with LDL to produce an LDL-ILE complex containing 200 +/- 100 molecules of drug per LDL particle. The LDL-ILE complex was highly electronegative as detected by electrophoresis. Further, this complex presented an immunologically detected over expression of the ligand-binding domain to the LDL receptor. In spite of these modifications, the LDL receptor processing bound, internalized, and degraded the LDL-ILE complex. Nevertheless, these biological properties were reduced by 32, 20, and 40%, respectively, in comparison to native LDL. Despite its high electronegativity, the LDL-ILE complex was not recognized by the macrophagic scavenger receptor. The LDL-ILE complex showed specific LDL receptor mediated in vitro cytotoxicity as judged from the growth inhibition of neoplastic A549 cells and of normal fibroblasts, but no activity on defective LDL receptor cells. Further, the pharmacological activity of the complex against A549 cells has been demonstrated to be equally potent as that of the free drug (median inhibitory dose, 5 microM). It is suggested that LDL drug targeting of AMA molecules could specifically deliver active molecules to cancer cells, avoiding their entrapment by other blood proteins and their rapid clearance by the reticuloendothelial system.

RhoB loss induces Rac1-dependent mesenchymal cell invasion in lung cells through PP2A inhibition.

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide, which is mainly due to its high risk of metastatic dissemination. One critical point of this process is the ability of cancer cells to detach from the primary tumor and migrate through the extracellular matrix; however, the underlying molecular mechanisms are not yet fully understood. In the present study, we identified the small GTPase RhoB as a key regulator of bronchial cell morphology in a three-dimensional (3D) matrix. RhoB loss, which is frequently observed during lung cancer progression, induced an epithelial-mesenchymal transition (EMT) characterized by an increased proportion of invasive elongated cells in 3D. The process was mediated by Slug induction and E-cadherin repression. In addition, downregulation of RhoB induced Akt1 activation, which in turn activated Rac1 through the guanine-exchange factor Trio to control cell shape rearrangement. Further, we provide evidence that RhoB interacted with and positively regulates phosphatase PP2A through the recruitment of its regulatory subunit B55, which was found to be crucial for Akt dephosphorylation. B55 inhibition completely suppressed RhoB-mediated PP2A regulation. Finally, we show that PP2A inactivation, by targeting either its catalytic or its regulatory B55 subunit, completely reversed RhoB-dependent morphological changes and also fully prevented the ability of RhoB to decrease the invasiveness of bronchial cells. Altogether, these results highlight a novel signaling axis and describe new molecular mechanisms that could explain the tumor suppressor role of RhoB in lung cancer. Therefore, we propose that RhoB could be responsible for early metastatic prevention by inhibiting the EMT-derived invasiveness of lung cells through the control of PP2A activity.

Surgical approach to vesicourethral anastomotic stricture following radical prostatectomy.

INTRODUCTION: Vesicourethral anastomotic stricture following prostatectomy is uncommon but represents a challenge for reconstructive surgery and has a significant impact on quality of life. The aim of this study was to relate our experience in managing vesicourethral anastomotic strictures and present the treatment algorithm used in our institution. PATIENTS AND METHODS: We performed a descriptive, retrospective study in which we assessed the medical records of 45 patients with a diagnosis of vesicourethral anastomotic stricture following radical prostatectomy. The patients were treated in the same healthcare centre between January 2002 and March 2015. Six patients were excluded for meeting the exclusion criteria. The stricture was assessed using cystoscopy and urethrocystography. The patients with patent urethral lumens were initially treated with minimally invasive procedures. Open surgery was indicated for the presence of urethral lumen obliteration or when faced with failure of endoscopic treatment. Urinary continence following the prostatectomy was determinant in selecting the surgical approach (abdominal or perineal). RESULTS: Thirty-nine patients treated for vesicourethral anastomotic stricture were recorded. The mean age was 64.4 years, and the mean follow-up was 40.3 months. Thirty-three patients were initially treated endoscopically. Seventy-five percent progressed free of restenosis following 1 to 4 procedures. Twelve patients underwent open surgery, 6 initially due to obliterative stricture and 6 after endoscopic failure. All patients progressed favourable after a mean follow-up of 29.7 months. CONCLUSIONS: Endoscopic surgery is the initial treatment option for patients with vesicourethral anastomotic strictures with patent urethral lumens. Open reanastomosis is warranted when faced with recalcitrant or initially obliterative strictures and provides good results.

Evidence for qualitative abnormalities in high-density lipoproteins from myeloma patients: the presence of amyloid A protein could explain HDL modifications.

HDL apolipoproteins (apo) from normal subjects and patients with multiple myeloma were studied by isoelectric focusing (IEF) and by two-dimensional gel electrophoresis. Qualitative abnormalities were detected in myeloma HDL apolipoproteins. We observed two new bands not previously described in this disease. As determined by IEF and two-dimensional gel electrophoresis, the relative molecular weight of these two proteins was 12,600, with pI = 6.04 and 6.36, respectively. They correspond to two isoforms of serum amyloid A protein (SAA), as confirmed by western blot assay against specific antiserum to SAA. The high sensitivity of this assay revealed also other SAA isoforms. Our data are consistent with the hypothesis that major apolipoproteins of normal HDL, apo A-I and apo A-II, could be displaced by SAA isoproteins in myeloma HDL. This could lead structural changes in HDL.

Proliferative effect of high density lipoprotein (HDL) and HDL fractions (HDL1,2, HDL3) on virus transformed lymphoblastoid cells.

The growth-promoting activities of plasma lipoproteins (LDL, HDL, HDL1,2, HDL3) and total HDL apolipoproteins on a virus transformed lymphoblastoid cell line in vitro, has been compared. When maintained in lipoprotein-deficient serum-supplemented medium, these cells do not proliferate optimally. The addition of either HDL, HDL1,2 or HDL3 induced optimal cell proliferation as compared to the result observed in fetal calf serum-supplemented medium. The HDL1,2 subfraction was found to be more potent than the HDL3 subfraction in supporting cell growth. Total HDL apolipoproteins were able to support significant cell proliferation. In contrast, LDL did not promote cell growth. In serum-free conditions and in the presence of transferrin, only HDL and HDL subfractions induced cell proliferation. These results suggest that HDL and HDL subfractions could initiate B lymphoblastoid cell growth and that total HDL apolipoproteins could support a part of cell proliferation.

Reversible dissociation of cortisol-transcortin complex by sodium para-chloromercuribenzoate.

Mercurials are considered as sulphydryl group specific reagents and one of them, sodium para-chloromercuribenzoate (PCMB), is currently used for SH titration. It has been shown that cellular steroid receptors are reversibly inactivated by mercurials even when the binding site is occupied by the steroid (Coty, W.A. (1980) J. Biol. Chem. 255, 8035-8037). This is a striking difference with alkylating SH reagents such as iodoacetic acid or N-ethylmaleimide, since these reagents inactivate only steroid-free receptors. In order to explain this discrepancy, we tested, in the present study, the specificity of PCMB on a blood plasma steroid binding protein: human transcortin. This protein presents the advantage, over cellular receptors, of being well characterized and to be available in a pure state. The transcortin-cortisol complex was also reversibly inactivated by PCMB when the reaction was carried out at a high excess of reagent over protein; such conditions are those previously used with steroid receptors. The reversibility was obtained not only with a reducing agent (dithiothreitol) but also with EDTA, which suggests a poor stability of the protein mercurial bond and therefore a nonspecific action. The decrease of activity was the result of a loss of binding sites and Scatchard plot analysis did not reveal any detectable decrease of the affinity constant for cortisol. Transcortin possesses two SH groups per molecule, one of these being buried in native conformation. After blockage of the accessible SH group by aminoethylation, transcortin kept the same activity, but when this aminoethylated transcortin was incubated with PCMB a loss of activity was obtained, although the residual buried SH group was again titrable with Ellman's reagent. Therefore, we can conclude that the action of PCMB on proteins must be interpreted with precaution, since it can induce an inactivation that is SH-independent.

Improved oligonucleotide uptake and stability by a new drug carrier, the SupraMolecular Bio Vector (SMBV).

Antisense oligodeoxynucleotides are potential therapeutic agents, but their development is still limited by both a poor cellular uptake and a high degradation rate in biological media. The strategy that we propose to face these problems is to use small synthetic carriers, around 30 nm diameter, the SupraMolecular Bio Vectors (SMBV). We used positively charged SMBV and settled the ionic incorporation of negatively charged oligonucleotides into these carriers. A minimal leakage of 10% of total incorporated oligonucleotides was then measured during two months. Both protection and uptake of oligonucleotides were then analyzed. On the one hand, we showed that the incorporation of oligonucleotides into the selected SMBV allows to significantly increase, 8 times, their half-life, in cell growth medium. On the other hand, the internalization of the SMBV, into cells, by an endosomal pathway has been characterized. The essential point is that the SMBV uptake elicits the simultaneous oligonucleotide uptake. The oligonucleotide amount that goes through cells within 5 h can be up to 30 times higher than for free oligonucleotides and the fraction of oligonucleotides that is present in the cytosol is increased up to 10 fold after incorporation into the SMBV. This study demonstrates the ability of SMBV to improve oligonucleotide cellular behaviour.