[Cochlear implantation and early outcomes in children with incompletely partition type â ¢ 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 phosphorylates α4ß2 nicotinic ACh receptors and promotes recovery from desensitization.

BACKGROUND AND PURPOSE: Nicotinic (ACh) receptor recovery from desensitization is modulated by PKC, but the PKC isozymes and the phosphorylation sites involved have not been identified. We investigated whether PKCε phosphorylation of α4ß2 nAChRs regulates receptor recovery from desensitization. EXPERIMENTAL APPROACH: Receptor recovery from desensitization was investigated by electrophysiological characterization of human α4ß2 nAChRs. Phosphorylation of the α4 nAChR subunit was assessed by immunoblotting of mouse synaptosomes. Hypothermia induced by sazetidine-A and nicotine was measured in Prkce(-/-) and wild-type mice. KEY RESULTS: Inhibiting PKCε impaired the magnitude of α4ß2 nAChR recovery from desensitization. We identified five putative PKCε phosphorylation sites in the large intracellular loop of the α4 subunit, and mutating four sites to alanines also impaired recovery from desensitization. α4 nAChR subunit phosphorylation was reduced in synaptosomes from Prkce(-/-) mice. Sazetidine-A-induced hypothermia, which is mediated by α4ß2 nAChR desensitization, was more severe and prolonged in Prkce(-/-) than in wild-type mice. CONCLUSIONS AND IMPLICATIONS: PKCε phosphorylates the α4 nAChR subunit and regulates recovery from receptor desensitization. This study illustrates the importance of phosphorylation in regulating α4ß2 receptor function, and suggests that reducing phosphorylation prolongs receptor desensitization and decreases the number of receptors available for activation.

AC conductivity of selectively located carbon nanotubes in poly(epsilon-caprolactone)/polylactide blend nanocomposites.

DC and AC electrical conductivity of bionanocomposites based on the immiscible polymer blend poly(epsilon-caprolactone)/polylactide (PCL/PLA, w/w 70/30), loaded with multiwall carbon nanotubes (CNT), were studied in a wide frequency range, 10(-3) < or = f < or = 10(7) Hz from 143 to 313 K. The nanofiller concentration ranged from 0 to 4 wt % and it was shown to be selectively located in the PCL phase. The PCL crystallinity degree was not affected by the presence of CNT. The variation of the DC conductivity allowed the determination of the percolation threshold, p(c) = 0.98 wt %, and the critical exponent t = 2.2 of the scaling law. The linear dependence of log (sigma(DC)) versus p(-1/3) showed the existence of tunneling conduction among CNT not yet in physical contact. The temperature independent results indicated a conventional tunnel effect. The AC conductivity of the nanocomposites followed the predictions of the universal dynamic response and the s exponents were determined at low concentrations. Master curves are presented showing the length and temperature-time superpositions.

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.

[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.

[Analysis of and repair capacity in 247 cancer patients and normal persons by nucleoid sedimentation technique].

The nucleoid sedimentation technique was developed to analyze DNA repair capacity in 108 cancer patients (esophageal cancer 34, lung cancer 24 and ovarian cancer 50) and 139 normal persons. After exposing lymphocytes to UV in radiation at the dose of 2.5 microJ/mm2, the cells were incubated for different periods of time at 37 degrees C for repairing the damaged DNA. The nucleoid sedimentation distance which corresponds to DNA repair capacity was determined. It was found that most normal persons finished the process of DNA repair in II hours while the cancer patients could not do so even 17 hours after incubation. This study showed that decreased DNA repair capacity may be a component of the genetically determined susceptibility to cancer.

[The subcellular distribution and covalent binding of 3H-(+) and 3H-(-) gossypol in the main tissues of rats].

The total and covalently bound radioactivity in various subcellular components in the main tissues of rats was measured 7 and 18 days after a single intraperitoneal and intratesticular injection of 3H-(+) and 3H-(-) gossypol. An increasing tendency of covalently bound radioactivity with time in the myocardial mitochondria and testicular cell membrane and microsomes of rats treated with (+) or (-) gossypol was found, especially in (-) gossypol treated rats. It remains to be clarified whether these are linked to the myocardial toxicity and to the antispermatogenic activity of gossypol.

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.