Adenovirus expressing p27(Kip1) induces growth arrest of lung cancer cell lines and suppresses the growth of established lung cancer xenografts

p27(Kip1) (p27) is a member of the universal cyclin-dependent kinase inhibitor (CDKI) family and a putative tumor suppressor gene. In several tumors including lung cancer, decreased expression of p27 is associated with poor prognosis. These observations suggest a potential role for p27 as a new gene therapy target. In this study, we constructed adenovirus expressing human p27 (ad-p27) and investigated its antitumor effects on human lung cancer cell lines. Upon transduction of several human lung cancer cells with ad-p27, a high level of p27 expression, with a decrease in cdk2 and an increase in cyclin E were observed. These changes resulted in G1/S arrest. Transduction of human lung cancer cell lines with ad-p27 showed in vitro growth inhibition and a marked suppression of colony formation upon soft agar clonogenic assay. Direct intratumoral injection of ad-p27 induced the growth suppression of established lung tumors in nude mice. From these observations, gene therapy using ad-p27 seems to offer a potential basis for the development of new cancer gene therapy modality and a useful tool to investigate the mechanisms of cell cycle control.

Interferon-alpha treatment of chronic hepatitis C in children with hemophilia

BACKGROUND

In children with hemophilia, hepatitis C virus (HCV) is the major cause of chronic liver disease. In this study, long-term efficacy of interferon-alpha was studied to determine the factors that predict a sustained response to interferon therapy in young children with hemophilia who have chronic hepatitis C.

METHODS

Seventeen Korean children with hemophilia and chronic hepatitis C were treated with 3.7 million units/m2 of interferon-alpha2a three times weekly for 6 months. Liver biopsy, pretreatment serum HCV RNA quantitation with competitive reverse transcription assay, and HCV genotyping with reverse hybridization assay were performed.

RESULTS

Hepatitis C virus genotypes 1a, 1b, and 2a were found in three (18%), five (29%), and six (35%) patients, respectively. Interferon-alpha was well tolerated, and the frequency of bleeding did not increase. Of the 17 patients, 7 (41%) had a sustained response for 3 years after the end of therapy. Patients with a sustained response had lower pretreatment serum HCV RNA levels. One (13%) of eight patients with genotype 1 and five (83%) of six with genotype 2 had a sustained response (P < 0.05).

CONCLUSIONS

Interferon-alpha treatment of chronic hepatitis C in children with hemophilia was safe and effective in producing sustained responses. The pretreatment serum HCV RNA level and viral genotype may be predictive factors for sustained response to interferon therapy.

Cell density regulates prolyl 4-hydroxylase activity independent of mRNA levels

In embryonic avian tendon, cell density regulates collagen production. This control is propagated through the alpha-subunit of prolyl 4-hydroxylase where protein levels were previously shown to rise fivefold with increasing cell density. In contrast, mRNA levels are now shown not to change by both Northern and RNAse protection assays. This lack of increase contrasts with previous reports as does the mRNA length: this is 50% larger as confirmed by sequencing the 3' end. Alternative sites for cell density regulation of the enzyme could rely on its sensitivity to sulfhydryl groups. Using a fluorescent sulfhydryl probe as well as a sulfhydryl inhibitor, one observes a strong cell density response, supporting the hypothesis that cellular redox potential could alter protein stability.

Odontogenic ghost cell carcinoma: a case report with reference to the relation between apoptosis and ghost cells

The neoplastic variant of calcifying odontogenic cyst has various designations, and its malignant counterpart has been reported as aggressive epithelial odontogenic ghost cell tumor or odontogenic ghost cell carcinoma. We present a case of odontogenic ghost cell carcinoma with reference to the relation between the ghost cells and apoptosis. A 33-year-old man complained of a mandibular mass. The mass occupied the entire right side of the mandible with destruction of both buccal and lingual bone. The mass also infiltrated into submandibular and sublingual spaces. Histologically, the mass was composed of a solid proliferation of hyperchromatic and pleomorphic epithelial cells with abnormal mitoses. Islands of ghost cells were frequently admixed with nucleated cells, and there were foci of ameloblastic differentiation. Immunohistochemical stains for cytokeratins, involucrin, and apoptosis-related proteins such as Bcl-2, Bcl-X(L), and Bax were done. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) assay was also performed. The nucleated cells adjacent to the ghost cells expressed cytokeratins and involucrin, but the ghost cells had no reaction. Bcl-2 was negative. Both Bcl-X(L) and Bax were demonstrated in the nucleated cells adjacent to the ghost cells. The ghost cells exhibited Bax protein. Some nucleated cells adjacent to the ghost cells were positive with TUNEL assay. The above results indicate that ghost cells undergo abnormal terminal differentiation as an apoptotic process.

Incidence of presbycusis of Korean populations in Seoul, Kyunggi and Kangwon provinces

Presbycusis, a bilateral sensorineural hearing loss caused by changes in the inner ear, is related to multiple factors such as noise exposure and otologic disease. In institute-based studies, we tried to determine the incidence of presbycusis in Korean populations living in Seoul, Kyunggi and Kangwon provinces by gender and age groups. The subjects were people who had visited health promotion centers. Pure tone audiometry was done over 20 years on 6,028 subjects. In a community-based study, the subjects were elderly residents of Kanghwa-do area. There were no obvious factors that could cause hearing impairment in the subjects. For the pure tone audiometry, hearing threshold was obtained by using the six-dimension method. The incidence of presbycusis for subjects aged 65 years and older was 37.8% and 8.3% for > or = 27 dB HL criterion and > or = 41 dB HL criterion, respectively. The incidence increased with age. A statistically significant difference in the hearing threshold was found between men and women aged 65 years or older. No differences were found between the community-based study and the institute- based studies. There was a high incidence (about 40%) of presbycusis among Koreans aged 65 years or older (for > or = 27 dB HL criterion). With an aging population, we anticipate that this report could be used to provide a basic data for the study of presbycusis.

A gel delivery system for coccidiosis vaccine: uniformity of distribution of oocysts

A patented gel delivery system being used to deliver coccidiosis vaccine to poultry hatchlings is assessed. For effective vaccination, the coccidial oocysts must be uniformly suspended before exposure to birds. The uniformity of distribution within the gel was evaluated by incorporating a culture of chicken gut flora into gel sausages, placing sections of the sausage on culture plates, determining the appearance and distribution of bacterial colonies on culture plates after incubation, and verifying by cell counts. The uniformity of distribution of similarly prepared coccidial oocysts was verified by infecting birds with 40,000 Eimeria tenella oocysts delivered via the gel. Gel-inoculated birds were compared with control birds inoculated PO with 40,000 oocysts suspended in water by using cecal lesion scores. Both the appearance and colony counts of chicken gut flora from the gel were uniform. The standard deviation in the lesion scores for the gel-inoculated group and the water-inoculated groups were 0.51 and 0.69, respectively. The results indicate that a gel delivery system can provide uniform distribution of live organisms and vaccine agents to birds.

Pure trigeminal motor neuropathy: a case report

Pure trigeminal motor neuropathy is a trigeminal motor paralysis unaccompanied by signs of trigeminal sensory or other cranial nerve involvement. We present a case of a 38-year-old man complaining of progressive weakness and wasting of the right masticatory muscles after a bout of mild cold symptoms. No sensory symptoms were present. History, neurologic examination, electrophysiologic studies, and magnetic resonance imaging of the brain led to the diagnosis of pure trigeminal motor neuropathy. The cause may have been an autoimmune reaction to a viral infection.

Mutations in the p53 tumor suppressor gene in tree shrew hepatocellular carcinoma associated with hepatitis B virus infection and intake of aflatoxin B1

Infection with hepadnaviruses and exposure to aflatoxin B1 (AFB1) are considered to be major risk factors in the development of hepatocellular carcinoma (HCC) in humans. A high rate of p53 mutations at codon 249 has been reported in these tumors. The tree shrew (Tupaia belangeri chinensis) is a useful animal model for the development of HCC after human hepatitis B virus (HBV) infection or AFB1 treatment. Therefore, it was of particular interest to determine whether the p53 gene in tree shrew HCCs associated with HBV infection and/or with exposure to AFB1 is affected in the same manner as in human HCCs. We determined the tree shrew p53 wild-type nucleotide sequences by RT-PCR and automatic DNA-sequencing. Tree shrew wild-type p53 sequence showed 91.7 and 93.4% homologies with human p53 nucleotide and amino acids sequences, respectively, while it showed 77.2 and 73.7% homologies in mice. One HCC and normal liver tissue from AFB1 treated and one HCC from AFB1- and HBV-treated tree shrew showed no change in p53 sequences, while three HCCs from AFB1- and HBV-treated tree shrews showed point mutations in p53 sequences. One HCC showed point mutations at codon 275, which is on the DNA-binding domain of p53 gene, which might be a cause of gain-of-function during the development of HCC. As a result, our finding indicates that tree shrews exposed to AFB1 and/or HBV had neither codon 249 mutations nor significant levels of other mutations in the p53 gene, as is the case with humans.

Overexpression of the transforming growth factor-beta-inducible gene betaig-h3 in anterior polar cataracts

PURPOSE

In anterior polar cataracts and the fibrosis that can occur after cataract surgery, lens epithelial cells synthesize abundant extracellular matrix molecules and transdifferentiate into myofibroblast-like cells. Transforming growth factor (TGF)-beta has been implicated as a key player in these cataractous changes. The purpose of this study was to determine whether the TGF-beta-inducible gene h3 (betaig-h3) is expressed in lens epithelial cells from patients with anterior polar cataracts and to test whether betaig-h3 is induced by TGF-beta in cultured lens epithelial cells.

METHODS

Lens epithelial cells attached to the anterior capsules of human cataractous lenses and noncataractous lenses were examined for the expression of betaig-h3 mRNA and protein using reverse transcription-polymerase chain reaction and immunohistochemical analyses. The effect of TGF-beta on betaig-h3 gene expression was also tested in human lens epithelial B-3 cells using Northern and Western blot analyses.

RESULTS

betaig-h3 mRNA was not detected in lens epithelial cells from patients with clear lenses or patients with nuclear cataracts. Significant expression of mRNA for betaig-h3 was observed in lens epithelial cells from patients with anterior polar cataracts. Immunohistochemical analysis using anti-betaig-h3 antiserum indicated that betaig-h3 protein was present within the subcapsular plaques of anterior polar cataracts. Treatment of human lens epithelial B-3 cells with TGF-beta1 led to an increase in betaig-h3 mRNA and the secretion of betaig-h3 protein into the culture medium.

CONCLUSIONS

betaig-h3 may serve as a marker for anterior polar cataracts in addition to previously known proteins, fibronectin, type I collagen, and alpha-smooth muscle actin. The functions of this protein in lens pathology need to be further investigated.

Seedling insensitivity to ozone for three conifer species native to Great Smoky Mountains National Park

Field symptoms typical of ozone injury have been observed on several conifer species in Great Smoky Mountains National Park, and tropospheric ozone levels in the Park can be high, suggesting that ozone may be causing growth impairment of these plants. The objective of this research was to test the ozone sensitivity of selected conifer species under controlled exposure conditions. Seedlings of three species of conifers, Table Mountain pine (Pinus pungens), Virginia pine (Pinus virginiana), and eastern hemlock (Tsuga canadensis), were exposed to various levels of ozone in open-top chambers for one to three seasons in Great Smoky Mountains National Park in Tennessee, USA. A combination of episodic profiles (1988) and modified ambient exposure regimes (1989-92) were used. Episodic profiles simulated an average 7-day period from a monitoring station in the Park. Treatments used in 1988 were: charcoal-filtered (CF), 1.0x ambient, 2.0x ambient, and ambient air-no chamber (AA). In 1989 a 1.5x ambient treatment was added, and in 1990, additional chambers were made available, allowing a 0.5x ambient treatment to be added. Height, diameter, and foliar injury were measured most years. Exposures were 3 years for Table Mountain pine (1988-90), 3 years for hemlock (1989-91), and 1 and 2 years for three different sets of Virginia pine (1990, 1990-91, and 1992). There were no significant (p<0.05) effects of ozone on any biomass fraction for any of the species, except for older needles in Table Mountain and Virginia pine, which decreased with ozone exposure. There were also no changes in biomass allocation patterns among species due to ozone exposure, except for Virginia pine in 1990, which showed an increase in the root:shoot ratio. There was foliar injury (chlorotic mottling) in the higher two treatments (1.0x and 2.0x for Table Mountain and 2.0x for Virginia pine), but high plant-to-plant variability obscured formal statistical significance in many cases. We conclude, at least for growth in the short-term, that seedlings of these three conifer species are insensitive to ambient and elevated levels of ozone, and that current levels of ozone in the Park are probably having minimal impacts on these particular species.

Induction of integrin-associated protein (IAP) mRNA expression during memory consolidation in rat hippocampus

We have previously demonstrated that hippocampal integrin-associated protein (IAP) gene expression is associated with memory formation in a one-way inhibitory avoidance learning in rats. In the present study, we further investigated the role and mechanism of IAP involved in memory consolidation in rats. Because of the minute amount of IAP present in the brain, we have adopted the quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. Our results revealed that hippocampal IAP mRNA expression is approximately fourfold higher in rats showing good memory retention (GM, retention score of 600 s) at 3 h, but not at other time points, after training when compared with the poor memory rats (retention score < 80 s). On the other hand, integrin alphav mRNA level was markedly increased ( approximately twofold), while integrin beta3 mRNA level was decreased ( approximately 50%) at 1 h post-training. Further, separate sets of RT-PCR analysis revealed that IAP5 and IAP6 mRNA expressions, but not that of IAP7, were markedly increased in GM rats 3 h post-training. Moreover, regional distribution studies revealed that different isoforms of the IAP gene are similarly distributed in different brain areas, while IAP7 has been the predominant form present in astrocyte cells. These results together suggest that IAP mRNA expression is indeed induced upon training, rather than that the GM rats have constitutively higher levels of IAP. The unparallel change of IAP and integrin mRNA expressions as far as time-course is concerned suggests that they are possibly involved in different forms and stages of memory processing. Further, IAP5 and IAP6 are more closely associated with memory consolidation, while IAP7 may constitute the major isotype for signal transduction in astrocyte cells.

Rapid, efficient detection and drug susceptibility testing of Mycobacterium tuberculosis in sputum by microscopic observation of broth cultures. The Tuberculosis Working Group in Peru

Inexpensive, rapid, and reliable methods of detecting infection by and drug susceptibility of Mycobacterium tuberculosis (MTB) are crucial to the control of tuberculosis. The novel microscopic observation broth-drug susceptibility assay (MODS) detects early growth of MTB in liquid medium, allowing more timely diagnosis and drug susceptibility testing. Sputum samples from hospitalized patients in Peru were analyzed by using stains, culture, and PCR. Sensitivity of MODS (92%) compared favorably with the most sensitive of the other culture methods (93%). Sputum samples positive for tuberculosis were tested for susceptibility to isoniazid and rifampin with the microwell alamar blue assay (MABA) and MODS. In 89% of cases, there was concordance between MODS and MABA. Of the diagnostic and susceptibility testing methods used, MODS yielded results most rapidly (median, 9.0 and 9.5 days, respectively). MODS is a rapid, inexpensive, sensitive, and specific method for MTB detection and susceptibility testing; it is particularly appropriate for use in developing countries burdened by significant infection rates and increasing numbers of multiple-drug-resistant cases.

Microsurgical anatomy of the perigeniculate ganglion area as seen from a translabyrinthine approach

Detailed anatomic knowledge of the microsurgical anatomy of the perigeniculate ganglion area is essential to probing adjacent to the facial nerve by a translabyrinthine approach. This study was designed to investigate the surgical anatomy of the perigeniculate ganglion area of the facial nerve from a translabyrinthine point of view. We dissected 15 human temporal bones under a microscope, measured the lengths of the tympanic segment and the labyrinthine segment by a middle cranial fossa approach, and measured the angle between the tympanic and labyrinthine segments by a translabyrinthine approach. The distance of the facial nerve from the cochleariform process to the geniculate ganglion was 3.8+/-0.7 mm. The length of the labyrinthine segment of the facial nerve was 4 +/-0.8 mm. The angle between the tympanic and labyrinthine segments from a translabyrinthine point of view was 26 degrees +/-5 degrees. Precise knowledge about the microsurgical anatomy of the perigeniculate ganglion area of the facial nerve from a translabyrinthine viewpoint is imperative for facial nerve decompression by a translabyrinthine approach.

Age-dependent increase in C7-1 gene expression in rat frontal cortex

We have previously reported that a fragment of mRNA, denoted as C7-1, which expression was significantly increased in the frontal cortex of aged rats. In the present study, we have cloned and sequenced the full length cDNA of the C7-1 gene. We have found that the open reading frame of this gene encoded a 463-amino-acid protein, which shared 84% identity in amino acid sequence with a subunit of vacuolar H(+)-ATPase (V-ATPase). Further Northern blot analysis revealed that there was an age-dependent increase in C7-1 gene expression in rat frontal cortex, but not in other brain areas. Moreover, application of C7-1 antisense oligonucleotide to cortical neuronal cultures markedly inhibited cell survival. These results together suggest that C7-1 is a marker for the aging process and that upregulation of C7-1 may be important in maintaining the normal function of V-ATPase during aging.

Evidence for bias in hair testing and procedures to correct bias

A number of in vitro experiments show that different hair samples incorporate differing amounts of drugs under identical conditions. Incorporation of cocaine and morphine tends to be correlated with race, in that the hair of African American females incorporates higher concentrations of cocaine than does the hair of Caucasian males or females. Extrapolation of these data into populations has been fraught with difficulties because the dosages of drugs and their use patterns are unknown. Cosmetic treatments and hygiene alter drug binding, which must be considered in comparing populations because cosmetic treatments are often group dependent. Four reasons are proposed that account for the uptake and retention of drugs by hair and that may differ among groups: (1) permeability and other characteristics of the hair due to genetic influences, (2) cosmetic hair treatments and hair care habits (which may be culturally influenced), (3) drug removal during personal hygiene, and (4) manner and route of drug administration which can affect passive exposure to residual drugs in the environment. The data supporting bias in hair testing are reviewed and methods are proposed that use either the uptake of dyes or the incorporation of drug homologs to reduce bias.

Corticotropin-releasing factor produces a protein synthesis--dependent long-lasting potentiation in dentate gyrus neurons

Corticotropin-releasing factor (CRF) was shown to produce a long-lasting potentiation of synaptic efficacy in dentate gyrus neurons of the rat hippocampus in vivo. This potentiation was shown to share some similarities with tetanization-induced long-term potentiation (LTP). In the present study, we further examined the mechanism underlying CRF-induced long-lasting potentiation in rat hippocampus in vivo. Results indicated that the RNA synthesis inhibitor actinomycin-D, at a concentration that did not change basal synaptic transmission alone (5 microgram), significantly decreased CRF-induced potentiation. Similarly, the protein synthesis inhibitor emetine, at a concentration that did not affect hippocampal synaptic transmission alone (5 microgram), also markedly inhibited CRF-induced potentiation. These results suggest that like the late phase of LTP, CRF-induced long-lasting potentiation also critically depend on protein synthesis. Further, prior maximum excitation of dentate gyrus neurons with tetanization occluded further potentiation of these neurons produced by CRF and vise versa. Moreover, quantitative reverse transcription-polymerase chain reaction analysis revealed that CRF mRNA level in the dentate gyrus was significantly increased 1 h after LTP recording. Together with our previous findings that CRF antagonist dose-dependently diminishes tetanization-induced LTP, these results suggest that both CRF-induced long-lasting potentiation and tetanization-induced LTP require protein synthesis and that CRF neurons are possibly involved in the neural circuits underlying LTP.

Ozone tolerance and antioxidant enzyme activity in soybean cultivars

The current study confirmed earlier conclusions regarding differential ozone (O(3)) tolerances of two soybean cultivars, Essex and Forrest, and evaluated antioxidant enzyme activities of these two varieties based on their performance under environmentally relevant, elevated O(3) conditions. The experiment was conducted in open-top chambers in the field during the 1994 and 1995 growing seasons. Exposure of plants to moderately high O(3) levels (62.9 nl l(-1) air, 2-year seasonal average) caused chlorophyll loss and increased membrane permeability when compared to control plants grown in charcoal filtered air (24.2 nl l(-1) air). The other effects of O(3) treatment were decrease in seed yield, loss of total sulfhydryl groups, reduction of soluble protein content, and increase in guaiacol peroxidase activity in leaves of both cultivars. The O(3)-induced increase in guaiacol peroxidase activity was much smaller in cv. Essex leaflets. Cv. Essex had less leaf oxidative damage and smaller reduction in seed yield than cv. Forrest under elevated O(3) conditions. During ozonation, mature leaflets of the more O(3) tolerant cv. Essex had higher levels of glutathione reductase (30%), ascorbate peroxidase (13%), and superoxide dismutase (45%) activity than did mature leaflets of cv. Forrest. Cu,Zn-superoxide dismutase, which represented 95% of total superoxide dismutase activity in the two cultivars, appeared to be increased by O(3) exposure in the leaflets of O(3) tolerant cv. Essex but not in those of cv. Forrest. Cytosolic ascorbate peroxidase activity was also higher in leaflets of cv. Essex than in cv. Forrest regardless of O(3) level. Stromal ascorbate peroxidase and Mn-superoxide dismutase activity did not appear to be involved in the O(3) tolerance of the two soybean cultivars.

Epidemiology, presentation and management of congenital muscular torticollis

AIM OF STUDY

Congenital muscular torticollis is a condition of debatable aetiology and management. Untreated, cervical function and facial cosmesis may be severely compromised. The aim of this study was to establish the epidemiology, presentation and management of congenital muscular torticollis in Singapore.

PATIENTS

Ninety-one patients with torticollis were seen at the National University Hospital (NUH) from January 1994 to December 1997. Torticollis was first noted at a median age of 2 months with the median age of presentation being 6 months. At presentation, a sternomastoid tumour was noted in 33 patients and 62 patients had facial asymmetry. Thirteen of 22 patients with neonatal records available had mandibular hypoplasia at birth on the side where the sternomastoid was affected. Half of the patients (45) had a right sided lesion, with 46 being left sided. The rates of assisted breech delivery, instrumental deliveries (forceps and vacuum) and Caesarean section were higher in the study group. Nine (59.1%) of 13 patients with vertex presentation, had a lesion on the side of the presenting shoulder. Forty-eight of 72 patients responded well to therapy with improvement; 20 underwent surgery and the median age of presentation of 19.5 months in this group was significantly later than that of 4 months in the group which responded to physiotherapy alone.

CONCLUSION

Birth trauma appears to be the main aetiological factor in congenital muscular torticollis. Patients generally respond well to physiotherapy. This study revealed 2 findings hitherto unreported: (1) mandibular hypoplasia may be an useful early sign of this condition, and (2) the side affected may depend on the side of shoulder delivered first. More studies, however, are required to confirm these findings.

Decreased azithromycin susceptibility of Neisseria gonorrhoeae due to mtrR mutations

Single-dose azithromycin therapy has recently been used in Uruguay for the treatment of uncomplicated gonococcal infections. As part of an active surveillance study to monitor the emergence of antibiotic resistance in gonococcal isolates, we examined the levels of azithromycin susceptibility in 51 consecutive isolates obtained from males with uncomplicated gonococcal urethritis. Isolates with decreased susceptibility to azithromycin (MICs, 0.25 to 0.5 microg/ml) were common, and these isolates often displayed cross-resistance to hydrophobic antimicrobial agents (erythromycin and Triton X-100). Resistance to erythromycin and Triton X-100 is frequently due to overexpression of the mtrCDE-encoded efflux pump mediated by mutations in the mtrR gene, which encodes a transcriptional repressor that modulates expression of the mtrCDE operon. Accordingly, we questioned whether clinical isolates that express decreased azithromycin susceptibility harbor mtrR mutations. Promoter mutations that would decrease the level of expression of mtrR as well as a missense mutation at codon 45 in the mtrR-coding region that would result in a radical amino acid replacement within the DNA-binding motif of MtrR were found in these strains. When these mutations were transferred into azithromycin-susceptible strain FA19 by transformation, the susceptibility of gonococci to azithromycin was decreased by nearly 10-fold. The mtrCDE-encoded efflux pump system was responsible for this property since insertional inactivation of the mtrC gene resulted in enhanced susceptibility of gonococci to azithromycin. We conclude that the mtrCDE-encoded efflux pump can recognize azithromycin and that the emergence of gonococcal strains with decreased susceptibility to azithromycin can, in part, be explained by mtrR mutations.

Impaired memory retention and decreased long-term potentiation in integrin-associated protein-deficient mice

Previously, we have demonstrated that integrin-associated protein (IAP) mRNA level is approximately fourfold higher in rats showing good retention performance (600 sec) than rats showing poor retention performance (< 80 sec) in an inhibitory avoidance learning paradigm. In the present study, we have used the gene-targeted IAP-deficient mice to further investigate the role of IAP involved in memory formation and hippocampal long-term potentiation (LTP) in vivo. Results revealed that there was a significant impairment in memory retention and a significant reduction in the magnitude of LTP in IAP-deficient mice when compared with the wild-type and heterozygote mice, whereas the wild-type and heterozygote animals did not show marked differences on these measures. Furthermore, the impairment in retention performance of IAP-deficient mice was not due to different sensitivities of these animals to the electric shock. When we examined locomotor activity and rotarod treadmill performance, no differences were observed among these three groups of animals either. Western blot analysis confirmed the lack of IAP protein in IAP-deficient mice, whereas IAP expression was similar in both the wild-type and heterozygote controls. These results together demonstrate that IAP plays an important role in the process of memory formation and synaptic plasticity in mice.

Glibenclamide induces apoptosis through inhibition of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels and intracellular Ca(2+) release in HepG2 human hepatoblastoma cells

Glibenclamide, an inhibitor of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels, induced apoptosis in a dose- and time-dependent manner in HepG2 human hepatoblastoma cells. Glibenclamide increased intracellular Ca(2+) concentration, which was significantly inhibited by Ca(2+) release blockers dantrolene and TMB-8. BAPTA/AM, an intracellular Ca(2+) chelator, and the Ca(2+) release blockers significantly inhibited glibenclamide-induced apoptosis. Glibanclamide also increased intracellular Cl(-) concentration, which was significantly blocked by CFTR Cl(-) channel activators levamisole and bromotetramisole. These activators also significantly inhibited both intracellular Ca(2+) release and apoptosis induced by glibenclamide. The expression of CFTR protein in the cells was confirmed by Western blot analysis. These results suggest that glibenclamide induced apoptosis through inhibition of CFTR Cl(-) channels and intracellular Ca(2+) release and that this protein may be a good target for treatment of human hepatomas.