Effectiveness and safety of REBACIN as a non-invasive intervention for persistent high-risk human papillomavirus infection: A real-world prospective multicenter cohort study

BACKGROUND

We previously reported that REBACIN effectively eliminates persistent high-risk human papillomavirus (hrHPV) infection. Here, we conducted a prospective multicenter cohort study to evaluate the safety and effectiveness of REBACIN, taking into account factors such as specific hrHPV subtype and patient's age.

METHODS

According to inclusion/exclusion criteria and participant willingness, 3252 patients were divided into REBACIN group while 249 patients into control group. Patients in REBACIN group received one course treatment of intravaginal administration of REBACIN while no treatment in control group. After drug withdrawal, participants in both groups were followed up.

RESULTS

The clearance rate of persistent hrHPV infection in REBACIN group was 60.64%, compared to 20.08% in control group. Specifically, the clearance rates for single-type infection of HPV16 or HPV18 were 70.62% and 69.23%, respectively, which was higher than that of HPV52 (59.04%) or HPV58 (62.64%). In addition, the single, double, and triple/triple+ infections had a clearance rate of 65.70%, 53.31%, and 38.30%, respectively. Moreover, 1635 patients under 40 years old had a clearance rate of 65.14%, while it was 55.08% for 1447 patients over 40 years old. No serious adverse effects were found.

CONCLUSION

This study confirmed that REBACIN can effectively and safely eliminate persistent hrHPV infection, which the clearance rate of HPV16/18 is higher than that of HPV52/58, the clearance rate of single-type infection is higher than that of multiple-type infections, and the clearance rate in young patients is higher than that in elder patients, providing a guidance for REBACIN application in clearing hrHPV persistent infection in real-world settings.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry Registration Number: ChiCTR1800015617 http://www.chictr.org.cn/showproj.aspx?proj=26529 Date of Registration: 2018-04-11.

REBACIN® inhibits E6/E7 oncogenes in clearance of human papillomavirus infection

Previous studies have demonstrated that REBACIN^® intervention eliminates persistent high-risk human papillomavirus (hrHPV) infection. The initial establishment and subsequent progression of cervical cancer mainly depends on two major oncogenes, E6/E7, and previous studies have proposed E6/E7 oncogenes as a target for therapeutic drug development. The aim of this study was to investigate in vitro and in vivo whether REBACIN^® inhibits E6/E7 oncogenes for elucidating the mechanism of REBACIN^® in the clearance of persistent hrHPV infection. In vitro, after REBACIN^® treatment, the growth of both Ca Ski and HeLa cervical cancer cells containing the E6/E7 oncogenes was prevented. In line with this finding is that E6/E7 expression was inhibited, which can be counteracted by the co-application of anti-REBACIN^® antibody. These studies demonstrated that REBACIN^® can effectively inhibit the growth of cervical cancer cells via targeting HPV E6/E7 expression. To further verify this finding in clinic, 108 volunteer patients with persistent hrHPV infections were randomly divided into REBACIN^®, recombinant human interferon alpha-2b (Immunological drug control), or no-treatment blank control groups, received intravaginal administration of REBACIN^®, interferon or no-treatment every other day for three months, and then followed up for E6/E7 mRNA assay. In REBACIN^® group, 68.57% of patients showed complete clearance of HPV E6/E7 mRNA, which was significantly higher compared to 25.00% in the interferon immunological drug control group and 20.00% in blank control group, confirming that REBACIN^® is potently efficacious on clearing persistent hrHPV infections via inhibition of HPV E6/E7 oncogenes.

Clinical trial registration

http://www.chictr.org.cn/historyversionpuben.aspx?regno=ChiCTR2100045911, identifier ChiCTR2100045911.

Case Report: Noninvasive Clinical Intervention of REBACIN® on Histologic Regression of High Grade Cervical Intraepithelial Neoplasia

High-risk human papillomavirus (hrHPV) persistent infection is the major cause of cervical cancer. Clinical intervention of hrHPV-associated high-grade squamous intraepithelial lesion (HSIL) is critical to prevent cervical cancer, and current treatment is surgery (an invasive therapy). However, some patients refuse to do so for an afraid of potential adverse effects on future fertility or other concerns which creates a critical need for development of non-invasive therapeutic strategies. Here, we report for the first time the cases of non-invasive intervention with REBACIN®, a proprietary antiviral biologics, in clinical treatment of HSIL. From 12,958 visiting patients assessed for eligibility, 18 HSIL-patients with cervical intraepithelial neoplasia-grade 2, positive of both diffused overexpression of p16 and high-risk HPV were enrolled in this non-invasive clinical intervention mainly due to concerns of future fertility. REBACIN® was administered intravaginally every other day for 3 months (one-course) except during menstrual period, and were followed up for 6-36 months for the examination of high-risk HPV DNA, cervical cytology, and histopathology. After one to three course treatments, most cases (16/18) displayed both the regression from HSIL (CIN2) to normal cervical cytology and clearance of high-risk HPV infection. Further studies demonstrated REBACIN® significantly suppressed HPV16 E7 oncoprotein expression in a human cervical cancer cell line, which is consistent with previous finding that REBACIN® inhibits the growth of tumors induced by expression of E6/E7 oncogenes of either HPV16 or HPV18. This report indicates REBACIN® as a novel effective non-invasive clinical intervention for HSIL-patients as well for high-risk HPV persistent infection, providing a new clinical option for the non-invasive treatment of hrHPV-associated high-grade squamous intraepithelial lesion, which is worthy of further research on clinical validation and application.

REBACIN® as a noninvasive clinical intervention for high-risk human papillomavirus persistent infection

The development of highly sensitive HPV-genotyping tests has opened the possibility of treating HPV-infected women before high-grade lesions appear. The lack of efficient intervention for persistent high-risk HPV infection necessitates the need for development of novel therapeutic strategy. Here we demonstrate that REBACIN®, a proprietary antiviral biologics, has shown potent efficacy in the clearance of persistent HPV infections. Two independent parallel clinical studies were investigated, which a total of 199 patients were enrolled and randomly divided into a REBACIN®-test group and a control group without treatment. The viral clearance rates for the REBACIN® groups were 61.5% (24/39) and 62.5% (35/56), respectively, for the two independent parallel studies. In contrast, the nontreatment groups showed self-clearance rates at 20.0% (8/40) and 12.5% (8/64). We further found that REBACIN® was able to significantly repress the expression of HPV E6 and E7 oncogenes in TC-1 and Hela cells. The two viral genes are well known for the development of high-grade premalignancy lesion and cervical cancer. In a mouse model, REBACIN® was indicated to notably suppress E6/E7-induced tumor growth, suggesting E6 and E7 oncogenes as a potential target of REBACIN®. Taken together, our studies shed light into the development of a novel noninvasive therapeutic intervention for clearance of persistent HPV infection with significant efficacy.

[Cochlear implantation and early outcomes in children with incompletely partition type Ⅲ malformation]

Objective:To analyze the early effect of the cochlear implantation (CI) in children with cochlear incompletely partition type Ⅲ malformation (IP-Ⅲ). Method:Ten children with IP-Ⅲ malformation who underwent CI were recruited in this study. The hearing characteristics, preoperative speech performance and surgery were analyzed retrospectively. The aided hearing threshold with CI, the categories of auditory performance (CAP) score, speech intelligibility rating (SIR) score and speech perception were designed to access the benefits of CI. Ten children with normal cochlea were also enrolled as the control group. Demographic information of children in the control group including hearing loss and speech level before implantation, age at implantation, hearing aids using history, duration with CI were matched with those in the IP-Ⅲ group. The hearing threshold, CAP score and SIR score in the IP-Ⅲ group were compared with the control group using the SPSS 20.0 software. Result:The computed tomography of temporal bones showed typical IP-Ⅲ malformation in all patients. The electrode arrays were properly and totally implanted in all children. Cerebrospinal fluid gusher occurred intra-operatively, and no other complications in all patients. The pure tone average (PTA) threshold at the 3rd, 6th, 9th and 12th month after implantation were (40.8±8.5) dB HL, (36.1±9.1) dB HL, (32.5±6.8) dB HL and (33.0±7.3) dB HL, respectively. The PTA thresholds in the IP-Ⅲ group were similar to those in the control group at all tested time points (P>0.05). At the 3rd, 6th, 9th and 12th month after implantation, the CAP scores in the IP-Ⅲ group were lower than those in the control group, but there was no significantly difference (P>0.05). Furthermore, the SIR scores were lower than those in the control group, and there were significantly difference at the 6 th, 9 th and 12 th month after implantation (P<0.05). Conclusion:CI was an effective treatment for children with IP-Ⅲ malformation. Surgery on IP-Ⅲ was challenging, however, seldom complication would occur with excellent surgical skills. Though the CI was benefit for IP-Ⅲ, the development of hearing and speech ability were slower than children with normal cochlea.

PKCε phosphorylation of the sodium channel NaV1.8 increases channel function and produces mechanical hyperalgesia in mice

Mechanical hyperalgesia is a common and potentially disabling complication of many inflammatory and neuropathic conditions. Activation of the enzyme PKCε in primary afferent nociceptors is a major mechanism that underlies mechanical hyperalgesia, but the PKCε substrates involved downstream are not known. Here, we report that in a proteomic screen we identified the NaV1.8 sodium channel, which is selectively expressed in nociceptors, as a PKCε substrate. PKCε-mediated phosphorylation increased NaV1.8 currents, lowered the threshold voltage for activation, and produced a depolarizing shift in inactivation in wild-type - but not in PKCε-null - sensory neurons. PKCε phosphorylated NaV1.8 at S1452, and alanine substitution at this site blocked PKCε modulation of channel properties. Moreover, a specific PKCε activator peptide, ψεRACK, produced mechanical hyperalgesia in wild-type mice but not in Scn10a-/- mice, which lack NaV1.8 channels. These studies demonstrate that NaV1.8 is an important, direct substrate of PKCε that mediates PKCε-dependent mechanical hyperalgesia.

A conserved cysteine residue in the third transmembrane domain is essential for homomeric 5-HT3 receptor function

The cysteine (Cys) residue at position 312 in the third transmembrane domain (M3) is conserved among 5-hydroxytryptamine type 3 (5-HT(3)) receptor subunits and many other subunits of the nicotinic acetylcholine (nACh) related Cys-loop receptor family, including most of the gamma-aminobutyric acid type A (GABA(A)) and glycine receptor subunits. To elucidate a possible role for the Cys-312 in human 5-HT(3)A receptors, we replaced it with alanine and expressed the 5-HT(3)A(C312A) mutant in HEK293 cells. The mutation resulted in an absence of 5-HT-induced whole-cell current without reducing homopentamer formation, surface expression or 5-HT binding. The 5-HT(3)A(C312A) mutant, when co-expressed with the wild-type 5-HT(3)A subunit, did not affect functional expression of receptors, suggesting that the mutant is not dominant negative. Interestingly, co-expression of 5-HT(3)A(C312A) with 5-HT(3)B led to surface expression of heteropentamers that mediated small 5-HT responses. This suggests that the Cys-312 is essential for homomeric but not heteromeric receptor gating. To further investigate the relationship between residue 312 and gating we replaced it with amino acids located at the equivalent position within other Cys-loop subunits that are either capable or incapable of forming functional homopentamers. Replacement of 5-HT(3)A Cys-312 by Gly or Leu (equivalent residues in the nACh receptor delta and gamma subunits) abolished and severely attenuated function, respectively, whereas replacement by Thr or Ser (equivalent residues in nACh receptor alpha7 and GABA(A) subunits) supported robust function. Thus, 5-HT(3)A residue 312 and equivalent polar residues in the M3 of other Cys-loop subunits are essential determinants of homopentameric gating.

Allosteric modulation of metabotropic glutamate receptor 5 affects phosphorylation, internalization, and desensitization of the micro-opioid receptor

Recent evidence suggests that opioid analgesia and tolerance can be modulated by metabotropic glutamate receptors. Therefore, we studied the functional coupling and desensitization of the micro-opioid receptor (MOR) in human embryonic kidney (HEK) 293 cells which co-express metabotropic glutamate receptor 5 (mGluR5). As demonstrated by the D-Ala2,N-MePhe4,Gl-ol5-enkephalin (DAMGO)-induced inhibition of intracellular cAMP level and by binding studies, the co-expression of mGluR5 had no substantial effect on the agonist binding sites and functional coupling of the MOR. However, in MOR/ mGluR5 co-expressing cells, the non-competitive mGluR5 antagonist MPEP (2-methyl-6-(phenyl-ethynyl)-pyridine) decreases the DAMGO-induced MOR phosphorylation, internalization, and desensitization, whereas non-selective competitive mGluR antagonists or agonists had no effects. These findings indicate that an allosteric modulation of mGluR5 can affect the agonist-induced MOR signalling and regulation. As a mechanistic basis for the observed effects we suggested an interaction/heterodimerization of MOR and mGluR5, which is supported by the DAMGO-induced co-internalization of MOR and mGluR5 and by the increase of MPEP binding sites (Bmax) and a change of the binding affinity (K(D)) of mGluR5 receptors after the co-expression of MOR. In addition, co-immunoprecipitation experiments revealed evidence for an interaction between MOR and mGluR5 which is facilitated by MPEP treatment.

mu-opioid receptor-stimulated synthesis of reactive oxygen species is mediated via phospholipase D2

We have recently shown that the activation of the rat mu-opioid receptor (MOPr, also termed MOR1) by the mu-agonist [D-Ala(2), Me Phe(4), Glyol(5)]enkephalin (DAMGO) leads to an increase in phospholipase D2 (PLD2) activity and an induction of receptor endocytosis, whereas the agonist morphine which does not induce opioid receptor endocytosis fails to activate PLD2. We report here that MOPr-mediated activation of PLD2 stimulates production of reactive oxygen molecules via NADH/NADPH oxidase. Oxidative stress was measured with the fluorescent probe dichlorodihydrofluorescein diacetate and the role of PLD2 was assessed by the PLD inhibitor D-erythro-sphingosine (sphinganine) and by PLD2-small interfering RNA transfection. To determine whether NADH/NADPH oxidase contributes to opioid-induced production of reactive oxygen species, mu-agonist-stimulated cells were pre-treated with the flavoprotein inhibitor, diphenylene iodonium, or the specific NADPH oxidase inhibitor, apocynin. Our results demonstrate that receptor-internalizing agonists (like DAMGO, beta-endorphin, methadone, piritramide, fentanyl, sufentanil, and etonitazene) strongly induce NADH/NADPH-mediated ROS synthesis via PLD-dependent signaling pathways, whereas agonists that do not induce MOPr endocytosis and PLD2 activation (like morphine, buprenorphine, hydromorphone, and oxycodone) failed to activate ROS synthesis in transfected human embryonic kidney 293 cells. These findings indicate that the agonist-selective PLD2 activation plays a key role in the regulation of NADH/NADPH-mediated ROS formation by opioids.

Membrane glycoprotein M6A promotes mu-opioid receptor endocytosis and facilitates receptor sorting into the recycling pathway

The interaction of mu-opioid receptor (MOPr) with the neuronal membrane glycoprotein M6a is known to facilitate MOPr endocytosis in human embryonic kidney 293 (HEK293) cells. To further study the role of M6a in the post-endocytotic sorting of MOPr, we investigated the agonist-induced co-internalization of MOPr and M6a and protein targeting after internalization in HEK293 cells that co-expressed HA-tagged MOPr and Myc-tagged M6a. We found that M6a, MOPr, and Rab 11, a marker for recycling endosomes, co-localized in endocytotic vesicles, indicating that MOPr and M6a are primarily targeted to recycling endosomes after endocytosis. Furthermore, co-expression of M6a augmented the post-endocytotic sorting of delta-opioid receptors into the recycling pathway, indicating that M6a might have a more general role in opioid receptor post-endocytotic sorting. The enhanced post-endocytotic sorting of MOPr into the recycling pathway was accompanied by a decrease in agonist-induced receptor down-regulation of M6a in co-expressing cells. We tested the physiological relevance of these findings in primary cultures of cortical neurons and found that co-expression of M6a markedly increased the translocation of MOPrs from the plasma membrane to intracellular vesicles at steady state and significantly enhanced both constitutive and agonist-induced receptor endocytosis. In conclusion, our results strongly indicate that M6a modulates MOPr endocytosis and post-endocytotic sorting and has an important role in receptor regulation.

Role of receptor internalization in the agonist-induced desensitization of cannabinoid type 1 receptors

Agonist-induced internalization of G protein-coupled receptors (GPCRs) is an important mechanism for regulating signaling transduction of functional receptors at the plasma membrane. We demonstrate here that both caveolae/lipid-rafts- and clathrin-coated-pits-mediated pathways were involved in agonist-induced endocytosis of the cannabinoid type 1 receptor (CB1R) in stably transfected human embryonic kidney (HEK) 293 cells and that the internalized receptors were predominantly sorted into recycling pathway for reactivation. The treatment of CB1 receptors with the low endocytotic agonist Delta9-THC induced a faster receptor desensitization and slower resensitization than the high endocytotic agonist WIN 55,212-2. In addition, the blockade of receptor endocytosis or recycling pathway markedly enhanced agonist-induced CB1 receptor desensitization. Furthermore, co-expression of phospholipase D2, an enhancer of receptor endocytosis, reduced CB1 receptor desensitization, whereas co-expression of a phospholipase D2 negative mutant significantly increased the desensitization after WIN 55,212-2 treatment. These findings provide evidences for the importance of receptor endocytosis in counteracting CB1 receptor desensitization by facilitating receptor reactivation. Moreover, in primary cultured neurons, the low endocytotic agonist Delta9-THC or anandamide exhibited a greater desensitization of endogenous CB1 receptors than the high endocytotic agonist WIN 55,212-2, CP 55940 or 2-arachidonoyl glycerol, indicating that cannabinoids with high endocytotic efficacy might cause reduced development of cannabinoid tolerance to some kind cannabinoid-mediated effects.

Pituitary adenylate cyclase-activating polypeptide is up-regulated in cortical pyramidal cells after focal ischemia and protects neurons from mild hypoxic/ischemic damage

The protective effect of pituitary adenylate cyclase-activating polypeptide (PACAP) in stroke models is poorly understood. We studied patterns of PACAP, vasoactive intestinal peptide, and the PACAP-selective receptor PAC1 after middle cerebral artery occlusion and neuroprotection by PACAP in cortical cultures exposed to oxygen/glucose deprivation (OGD). Within hours, focal ischemia caused a massive, NMDA receptor (NMDAR)-dependent up-regulation of PACAP in cortical pyramidal cells. PACAP expression dropped below the control level after 2 days and was normalized after 4 days. Vasoactive intestinal peptide expression was regulated oppositely to that of PACAP. PAC1 mRNA showed ubiquitous expression in neurons and astrocytes with minor changes after ischemia. In cultured cortical neurons PACAP27 strongly activated Erk1/2 at low and p38 MAP kinase at higher nanomolar concentrations via PAC1. In astrocyte cultures, effects of PACAP27 on Erk1/2 and p38 were weak. During OGD, neurons showed severely reduced Erk1/2 activity and dephosphorylation of Erk1/2-regulated Ser112 of pro-apoptotic Bad. PACAP27 stimulation counteracted Erk1/2 inactivation and Bad dephosphorylation during short-term OGD but was ineffective after expanded OGD. Consistently, PACAP27 caused MEK-dependent neuroprotection during mild but not severe hypoxic/ischemic stress. While PACAP27 protected neurons at 1-5 nmol/L, full PAC1 activation by 100 nmol/L PACAP exaggerated hypoxic/ischemic damage. PACAP27 stimulation of astrocytes increased the production of Akt-activating factors and conferred ischemic tolerance to neurons. Thus, ischemia-induced PACAP may act via neuronal and astroglial PAC1. PACAP confers protection to ischemic neurons by maintaining Erk1/2 signaling via neuronal PAC1 and by increasing neuroprotective factor production via astroglial PAC1.

Membrane glycoprotein M6a interacts with the micro-opioid receptor and facilitates receptor endocytosis and recycling

Using a yeast two-hybrid screen, the neuronal membrane glycoprotein M6a, a member of the proteolipid protein family, was identified to be associated with the mu-opioid receptor (MOPr). Bioluminescence resonance energy transfer and co-immunoprecipitation experiments confirmed that M6a interacts agonist-independently with MOPr in human embryonic kidney 293 cells co-expressing MOPr and M6a. Co-expression of MOPr with M6a, but not with M6b or DM20, exists in many brain regions, further supporting a specific interaction between MOPr and M6a. After opioid treatment M6a co-internalizes and then co-recycles with MOPr to cell surface in transfected human embryonic kidney 293 cells. Moreover, the interaction of M6a and MOPr augments constitutive and agonist-dependent internalization as well as the recycling rate of mu-opioid receptors. On the other hand, overexpression of a M6a-negative mutant prevents mu-opioid receptor endocytosis, demonstrating an essential role of M6a in receptor internalization. In addition, we demonstrated the interaction of M6a with a number of other G protein-coupled receptors (GPCRs) such as the delta-opioid receptor, cannabinoid receptor CB1, and somatostatin receptor sst2A, suggesting that M6a might play a general role in the regulation of certain GPCRs. Taken together, these data provide evidence that M6a may act as a scaffolding molecule in the regulation of GPCR endocytosis and intracellular trafficking.

Interaction of the mu-opioid receptor with synaptophysin influences receptor trafficking and signaling

There is increasing evidence that the signal transduction of opioid receptors is modulated by receptor-associated proteins. In the search for proteins regulating mu-opioid receptor (MOPr) endocytosis, synaptophysin was found to bind to the rat micro-opioid receptor in yeast two-hybrid assay. Coimmunoprecipitation experiments and bioluminescence resonance energy transfer assays confirmed that the micro-opioid receptor constitutively interacts with synaptophysin in human embryonic kidney 293 cells overexpressing MOPr and synaptophysin. In this study, we show that overexpression of synaptophysin enhances the micro-opioid receptor endocytosis. One explanation for the observed effects is that synaptophysin recruits dynamin to the plasma membrane, facilitating fission of clathrin-coated vesicles. This suggestion is supported by our finding that overexpression of a synaptophysin truncation mutant, which breaks the interaction between synaptophysin and dynamin, prevents agonist-mediated micro-opioid receptor endocytosis. In addition, the synaptophysin-augmented micro-opioid receptor trafficking leads to attenuated agonist-induced receptor desensitization and faster receptor resensitization. Taken together, our findings strongly suggest that synaptophysin plays an important role in the regulation of micro-opioid receptor trafficking and signaling.

Role of phospholipase D2 in the agonist-induced and constitutive endocytosis of G-protein coupled receptors

We have recently shown that the mu-opioid receptor [MOR1, also termed mu-opioid peptide (MOP) receptor] is associated with the phospholipase D2 (PLD2), a phospholipid-specific phosphodiesterase located in the plasma membrane. We further demonstrated that, in human embryonic kidney (HEK) 293 cells co-expressing MOR1 and PLD2, treatment with (D-Ala2, Me Phe4, Glyol5)enkephalin (DAMGO) led to an increase in PLD2 activity and an induction of receptor endocytosis, whereas morphine, which does not induce opioid receptor endocytosis, failed to activate PLD2. In contrast, a C-terminal splice variant of the mu-opioid receptor (MOR1D, also termed MOP(1D)) exhibited robust endocytosis in response to both DAMGO and morphine treatment. We report here that MOR1D also mediates an agonist-independent (constitutive) PLD2-activation facilitating agonist-induced and constitutive receptor endocytosis. Inhibition of PLD2 activity by over-expression of a dominant negative PLD2 (nPLD2) blocked the constitutive PLD2 activation and impaired the endocytosis of MOR1D receptors. Moreover, we provide evidence that the endocytotic trafficking of the delta-opioid receptor [DOR, also termed delta-opioid peptide (DOP) receptor] and cannabinoid receptor isoform 1 (CB1) is also mediated by a PLD2-dependent pathway. These data indicate the generally important role for PLD2 in the regulation of agonist-dependent and agonist-independent G protein-coupled receptor (GPCR) endocytosis.

[Sodium ferulate alleviates prednisolone induced liver toxicity in mice]

Prednisolone (Pred) 20 mg.kg-1 sc caused an increase in serum glutamicpyruvic transaminase (sGPT) and serum glutathione S-transferase (sGST) activities and an elevation of MDA content in mouse liver homogenate. An increase of membrane fluidity of liver microsomes and mitochondria was also observed. The results indicate that the elevations of sGPT and sGST levels were related to enhancement of lipid peroxidation and membrane fluidity in Pred-treated mice. Pretreatment with sodium ferulate (SF) 100 mg.kg-1 partially alleviated the liver lesions as observed by electron microscope observation. The sGPT and sGST levels and liver homogenate MDA content were reduced, and the membrane fluidity of liver microsomes was recovered. But, the membrane fluidity of liver mitochondria was further elevated. The results demonstrate partial inhibitory effect of sodium ferulate on prednisolone-induced liver toxicity.

Measurement of urinary clusterin as an index of nephrotoxicity

Measurements of tissue immunoassayable clusterin, a protein associated with programmed cell death and tissue reorganization, were performed in rats treated with nephrotoxic doses of gentamicin sulfate. Adult Lewis rats were treated with 100 mg/kg/day of gentamicin sulfate for 12 days. Urine, serum, and tissue levels of clusterin protein were measured, as were urinary N-acetyl beta-glucosaminidase (NAG) and serum creatinine levels. Induction of renal injury by gentamicin was detectable within 4 days by increased levels of urinary N-acetyl beta-glucosaminidase (from 280 +/- 66 (mean +/- SD) to 910 +/- 210 nmol/mg creatinine), and within 9 days of initiating gentamicin treatment by increased serum creatinine (from 0.5 +/- 0.1 to 1.2 +/- 0.4 mg/dl). Paralleling these changes, renal, urinary, and serum levels of clusterin increased 10-, 116-, and 3-fold (P less than 0.05). Treatment with gentamicin sulfate did not increase clusterin levels in the seminal vesicle, ventral prostate, testis, or epididymis. The measurement of urinary or serum clusterin may play a role in the early detection of renal injury.

Rapid decrease of cytochrome P-450IIE1 in primary hepatocyte culture and its maintenance by added 4-methylpyrazole

Studies were conducted to evaluate the possible induction or the maintenance of cytochrome P-450IIE1 in primary hepatocyte cultures by the inducing agent 4-methylpyrazole. Hepatocytes were isolated from control (noninduced) rats and from rats treated in vivo with either pyrazole or 4-methylpyrazole to induce P-450IIE1. The content of P-450IIE1 was determined by Western blots with antipyrazole P-450 IgG, and catalytic activity was assessed by assays of dimethylnitrosamine demethylase activity. The treatment with 4-methylpyrazole in vivo increased the content of P-450IIE1 and dimethylnitrosamine demethylase activity sevenfold and fourfold, respectively. In cultures prepared from noninduced hepatocytes, P-450IIE1 levels fell to values of 76%, 65%, 31% and 1% of freshly isolated hepatocytes after 1, 3, 6 and 9 days in culture. A similar decrease in dimethylnitrosamine demethylase was observed during this time. In cultures prepared from induced hepatocytes, the decline in P-450IIE1 was more rapid as levels fell to 77%, 31%, 3% and 3% of initial values after 1, 3, 6 and 9 days in culture. Again, the fall in dimethylnitrosamine demethylase activity paralleled the decline in content of P-450IIE1 and was more rapid with the induced hepatocytes. With cultures prepared from noninduced or induced hepatocytes, the addition of 4-methylpyrazole in vitro did not increase the content of P-450IIE1 or the activity of dimethylnitrosamine demethylase over the initial values. However, 4-methylpyrazole appeared to stabilize the P-450IIE1 and to decrease its rate of decline in culture. In noninduced cultures, the percent remaining content of P-450IIE1 after 6 days was 31% in the absence of and 52% in the presence of 5 mol/L 4-methylpyrazole. In cultures from 4-methylpyrazole-induced hepatocytes, the percent remaining P-450IIE1 after 3 days was 31% in the absence of inducer and 59% with 4-methylpyrazole added in vitro. Similarly 4-methylpyrazole helped to prevent the rapid decline of dimethylnitrosamine demethylase activity in induced and noninduced cultures. Viability of the induced and noninduced cultures in the absence or presence of added 4-methylpyrazole was similar. Levels of mRNA for P-450IIE1 were similar for livers from control rats and from rats treated in vivo with 4-methylpyrazole. The mRNA levels rapidly declined in induced and noninduced cultures, and this decline, unlike the fall in P-450IIE1 or dimethylnitrosamine demethylase activity, could not be prevented by the addition of 4-methylpyrazole in vitro to the cultures.(ABSTRACT TRUNCATED AT 400 WORDS)

Stereoselective interaction between gossypol and rat plasma

Gossypol, a potential male oral contraceptive, is chiral and chemically reactive. The present study was done to learn more about the stereoselective activity of this drug. The isomers were equipotent in hemolyzing erythrocytes in protein-free buffer while (+) gossypol was a more potent hemolysin than (-) in plasma. Both isomers disappeared from buffer at the same rate while (-) disappeared from plasma much faster than (+). Treating plasma with aspirin or DNFB to react with the free amino groups on the protein, slowed the disappearance of (-) gossypol. We conclude that (-) gossypol binds to free amino groups on protein and this stereoselective protein binding may account for some of the pharmacokinetic or pharmacodynamic difference between the two isomers of gossypol.

Lack of effect of glutathione depletion by L-buthionine-S,R-sulfoximine on gentamicin nephrotoxicity in rats

The mechanism of gentamicin-induced renal proximal tubular cell injury is not known, but generation of reactive oxygen species with subsequent lipid peroxidation has been proposed. In this study, male adult rats were given gentamicin and L-buthionine-S,R-sulfoximine (BSO), a selective glutathione (GSH)-depleting agent, to determine the effects of GSH depletion on acute gentamicin-induced nephrotoxicity. Urinary N-acetyl-beta-glucosaminidase (NAG) excretion increased equally in the groups given gentamicin alone compared to the groups given gentamicin and BSO. BSO treatment alone did not increase NAG excretion. GSH depletion by BSO did not enhance either gentamicin-induced azotemia or the degree of cell necrosis seen by light microscopy. In conclusion, BSO-induced GSH deficiency does not enhance acute gentamicin nephrotoxicity, suggesting that reactive oxygen species are not the major initiating cause of gentamicin-induced acute kidney injury.

[DNA repair capacity, chromosome aberration rate and chromosome fragile sites among members of 7 cancer families]

A nucleoid sedimentation technique was developed and used for analysis of DNA repair capacity in 40 members from 7 cancer families. Chromosome aberration rate (CAR) and chromosome fragile sites (CFS) were assayed simultaneously for comparison. It was shown that 32 members (80%) had a decreased DNA repair capacity and 34 (85%) had increased CAR as well as an apparent increase of CFS. 28 members (70%) showed both decreases of DNA repair capacity and increases of CAR. The importance of these criteria in heritable susceptibility to cancer is discussed.

Determination of gossypol enantiomers in plasma after administration of racemate using high-performance liquid chromatography with precolumn chemical derivatisation

A high-performance liquid chromatographic assay with precolumn chemical derivatisation was developed for the determination of gossypol enantiomers in plasma, after administration of the racemate. Racemic gossypol acetic acid in plasma was extracted into acetonitrile and analysed using a reversed-phase column and a coulometric detector in the redox mode. To separate the enantiomers, 30 microliters of the chiral derivatising reagent, (R)-(-)-2-amino-1-propanol (50 mg/ml) and 15 microliters of 20% (v/v) acetic acid were added to the acetonitrile layer which was then heated at 60 degrees C for 100 min. The mobile phase used to resolve the derivatised enantiomers was 0.2 M phosphate buffer (pH 3.5)-acetonitrile (38:62, v/v). At a flow-rate of 1.5 ml/min, the retention times for derivatised (+)-gossypol and (-)-gossypol were 4.0 and 7.8 min, respectively. Two cancer patients received 10 mg racemic gossypol acetic acid three times a day. In one patient, the racemic, (+)- and (-)-gossypol acetic acid plasma concentrations after 65 days of therapy were 317, 213 and 104 ng/ml, respectively. In the other patient, these values were 362, 210 and 152 ng/ml, respectively, after a week of therapy. This represents, to our knowledge, the first determination of the individual enantiomer levels of gossypol after administration of the racemate.

Pharmacokinetics of (+/-)-, (+)-, and (-)-gossypol in humans and dogs

Pharmacokinetic parameters of (+/-)-, (+)-, and (-)-gossypol were determined in humans and dogs after a single oral or intravenous dose. Mean (+/- SD) oral bioavailability of (+/-)-gossypol in dogs was 30.9% +/- 16.2%. Studies in dogs who received single intravenous injections revealed that the elimination t1/2 and volume of distribution of (+)-gossypol were five and six times those of (-)-gossypol, respectively, whereas total body clearance and the AUC of the two enantiomers were similar. Data from men receiving the compounds orally show that the average peak plasma concentration and the AUC of (+)-gossypol are significantly greater than those of the (-)-isomer. The rate constants of alpha, beta, ka, k21, and k10 for (-)-gossypol are significantly greater than those for (+)-gossypol, indicating higher rates of mass transfer of the (-)-species. In humans the elimination t1/2 of (+)-gossypol was 29 times as that of (-)-gossypol, a difference that is more striking than that found in dogs. The elimination t1/2 of (+/-)-gossypol in humans averages 286 +/- 179 hours.

[Mixed function oxidase isolated from human gastric epithelium in Fujian Province, a high incidence area of stomach cancer, and its role in the metabolism of diethylnitrosamine]

Mixed function oxidase (MFO) was isolated from the mucosa of human stomach in Fujian Province, a high incidence area of stomach cancer. Its activity was analyzed using a modified micromethod. In the non-cancer group, the activity of MFO in high incidence area of stomach cancer was significantly higher than that in low incidence area (P less than 0.001). A significant difference was also observed between stomach cancer and non-cancer groups. But the MFO concentrations between the high and low incidence areas were not different. These results suggest that the high MFO activity in gastric mucosal epithelial cells may cause higher incidence of stomach cancer. MFO isolated from human gastric epithelium is capable of metabolizing directly diethylnitrosamine in vitro.

High-performance liquid chromatography with electrochemical detection of gossypol in human plasma

A sensitive and selective high-performance liquid chromatographic method with electrochemical detection for the determination of gossypol in human plasma is described. Glutathione is used as a protective agent and gossypol dimethyl ether as an internal standard. Acetonitrile-treated protein-free plasma sample is first introduced on to a C18 pre-column for enrichment and clean-up. By using a column-switching technique, gossypol and the internal standard are subjected to further separation on a C8 analytical column, while the major interfering components are eliminated before entering the column. Methanol-0.1 M citrate buffer (pH 3.2) (80:20) is used as the mobile phase. The detector potential on the glassy carbon electrode is maintained at +0.6 V vs. an Ag-AgCl reference electrode. The linearity with human plasma ranged from 5 to 250 ng/ml. The absolute recoveries of gossypol and gossypol dimethyl ether were 91.3 and 97.5%, respectively, with a within-day precision of 2.5% and a day-to-day precision of 3.8%. The limit of detection is 5 ng/ml (signal-to-noise ratio = 3:1). The method is considered to be suitable for the clinical pharmacokinetic studies of gossypol.

Malignant transformation of baby hamster lung fibroblasts induced in vitro by a new nitrosamine compound

A new nitrosamine compound, N-1-methylacetonyl-N-3-methylbutyl-nitrosamine (MAMB-NA), isolated from corn bread inoculated with moulds commonly occurring in Linxian County, a high incidence area for esophageal cancer in North China was tested for its potential carcinogenicity in vitro. Baby hamster lung fibroblasts (BHL) were treated with MAMBNA in tissue culture medium containing liver microsome preparation of Aroclor 1254 treated rat. Cell transformation was assessed by morphological changes, loss of density-dependent inhibition and unlimited growth in vitro, chromosome changes, colony formation on soft agar, growth at low serum concentration, Con A agglutinability and tumor formation after heterotransplantation into immunosuppressed newborn rats. Like the known carcinogens N-methyl-N'-nitro-N-nitroso-guanidine and diethylnitrosamine, MAMBNA was able to cause malignant transformation of cells cultured in vitro.