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Articles by H. J Lee
Total Records ( 20 ) for H. J Lee
  Y. E Chung , M. S Park , Y. N Park , H. J Lee , J. Y Seok , J. S Yu and M. J. Kim
 

OBJECTIVE. The purpose of this article is to show the imaging findings of variant types of hepatocellular carcinoma (HCC) with pathologic correlations.

CONCLUSION. The variant types of HCC may not share its typical imaging characteristics. An understanding of the radiologic findings for variant types of HCC can be helpful in the differential diagnosis of hepatic tumors.

  S. C Park , D. H Lee , H. J Lee and C. Kee
 

Objective  To identify risk factors for normal-tension glaucoma among subgroups of patients.

Methods  In 93 patients with unilateral normal-tension glaucoma, intereye comparison of baseline spherical equivalent, central corneal thickness, untreated intraocular pressure, disc area, and zone β variables was performed among the following 4 subgroups classified according to age and visual field pattern standard deviation of the eye with glaucoma: subgroup 1 (age ≤50 years and visual field pattern standard deviation ≤8 dB), subgroup 2 (≤50 years and >8 dB), subgroup 3 (>50 years and ≤8 dB), and subgroup 4 (>50 years and >8 dB).

Results  Fourteen, 27, 30, and 22 patients were included in subgroups 1, 2, 3, and 4, respectively. The untreated intraocular pressure in subgroup 1 (P = .005), the zone β variables in subgroup 2 (P < .001), and both the untreated intraocular pressure (P = .010 and P = .034, respectively) and the zone β variables (P ≤ .008 and P ≤ .006, respectively) in subgroups 3 and 4 were significantly greater in the eyes with glaucoma than in the normal contralateral eyes (by paired t test or Wilcoxon signed rank test). The other variables showed no significant difference between the eyes in any subgroup.

Conclusion  The zone β variables (and not the untreated intraocular pressure) may represent significant risk factors in young patients having normal-tension glaucoma with moderate to severe visual field loss.

  C. H Lee , J. H Mo , I. J Choi , H. J Lee , B. S Seo , D. Y Kim , P. Y Yun , I. Y Yoon , H Won Lee and J. W. Kim
 

Objectives  To evaluate retrospectively the efficacy of the mandibular advancement device (MAD) in Korean patients with obstructive sleep apnea (OSA) in terms of severity and to evaluate prognostic factors deciding the success of MAD application.

Design  Retrospective analysis.

Setting  Academic tertiary referral center.

Patients  Of 142 patients who underwent MAD application for OSA management, 50 (46 men and 4 women; mean [SD] age, 50.2 [9.8] years) were included from March 2005 through August 2007.

Intervention  Full-overnight polysomnography was performed before and at least 3 months after intraoral MAD application in 50 patients. Questionnaires for sleep quality, Epworth sleepiness scale, and cephalometry were also studied.

Main Outcome Measures  Treatment results were evaluated and prognostic factors deciding success of MAD application were assessed.

Results  The mean (SD) apnea-hypopnea index (AHI) decreased significantly (P < .001) from 36.6 (18.9) to 12.3 (11.4). The success rate, defined by an AHI of lower than 20 and a 50% decrease in AHI, were 74% (37 of 50 patients). Even patients who were not categorized into the success group had a decreased AHI. The success rates of patients with mild, moderate, and severe OSA were 43% (3 of 7), 82% (22 of 27), and 75% (12 of 16), respectively, and a higher success rate in patients with severe OSA showed that MAD could be applied even in patients with severe OSA. The duration of apnea and hypopnea, percentage of patients with snoring, and the Pittsburgh Sleep Quality Index were improved significantly after treatment. Epworth sleepiness scale scores and lowest oxygen saturation did not change significantly. An analysis of prognostic factors did not reveal any significant difference between the success and nonsuccess groups.

Conclusions  The application of MAD significantly improved nocturnal respiratory function and sleep quality in patients with OSA, even in patients with severe OSA. In patients with OSA, MAD can be used as a good alternative treatment modality regardless of severity because it is noninvasive, easy to manufacture, and has good treatment results.

  C. H Lee , J. W Kim , H. J Lee , P. Y Yun , D. Y Kim , B. S Seo , I. Y Yoon and J. H. Mo
 

Objective  To quantitatively evaluate the effects of the mandibular advancement device (MAD) on changes in the upper respiratory tract during sleep using sleep videofluoroscopy (SVF) in patients with obstructive sleep apnea (OSA).

Design  Retrospective analysis.

Setting  Academic tertiary referral center.

Patients  Seventy-six patients (68 men and 8 women) who were treated with the MAD for OSA were included from September 1, 2005, through August 31, 2008.

Intervention  All patients underwent nocturnal polysomnography and SVF before and at least 3 months after receipt of the custom-made MAD. Sleep videofluoroscopy was performed before and after sleep induction and was analyzed during 3 states of awakeness, normoxygenation sleep, and desaturation sleep.

Main Outcome Measures  Changes in the length of the soft palate, retropalatal space, retrolingual space, and angle of mouth opening were evaluated during sleep events with or without the MAD.

Results  Without the MAD, the length of the soft palate and the angle of mouth opening increased during sleep events, especially in desaturation sleep, compared with the awake state. The retropalatal space and retrolingual space became much narrower during sleep compared with the awake state. The MAD had marked effects on the length of the soft palate, retropalatal space, retrolingual space, and angle of mouth opening. The retropalatal space and retrolingual space were widened, and the length of the soft palate was decreased. The MAD kept the mouth closed.

Conclusions  Sleep videofluoroscopy showed dynamic upper airway changes in patients with OSA, and the MAD exerted multiple effects on the size and configuration of the airway. Sleep videofluoroscopy demonstrated the mechanism of action of the MAD in patients with OSA. The MAD increased the retropalatal and retrolingual spaces and decreased the length of the soft palate and the angle of mouth opening, resulting in improvement of OSA.

  H Chang , H. J Lee , J. H Mo , C. H Lee and J. W. Kim
 

Objective  To evaluate the relationship between findings via osteomeatal unit computed tomography (OMU CT) of the olfactory cleft and olfactory function in patients with chronic rhinosinusitis (CRS).

Design  Retrospective review of medical records.

Setting  Referral center.

Participants  Two hundred ten patients with CRS who underwent OMU CT and olfactory function tests were included in this study.

Main Outcome Measures  All the paranasal sinuses were graded via the Lund-Mackay scoring system. The olfactory cleft was graded on a scale of 0 to 4 according to its opacification. Olfactory function was evaluated by the butanol threshold test (BTT) and the 16-odor identification test (OIT).

Results  The radiologic grade of the olfactory cleft was more significantly correlated with olfactory function than the grades of the paranasal sinuses. In patients without allergy, the BTT and OIT scores were inversely correlated with the CT score of the olfactory cleft. However, in patients with allergy, only the BTT score had a negative correlation with the CT score of the olfactory cleft, whereas the OIT score did not. The OIT score showed a significant negative correlation with the opacification of the olfactory cleft in the mild and moderate CRS group only, whereas the BTT score showed a significant negative correlation in all stages of CRS.

Conclusions  The opacification of the olfactory cleft had a negative correlation with the olfactory function scores in patients with CRS. The olfactory cleft findings on OMU CT may give some clues to the olfactory function in patients with CRS.

  B. S Seo , H. J Lee , J. H Mo , C. H Lee , C. S Rhee and J. W. Kim
 

Objective  To analyze the efficacy of treating postviral olfactory loss with glucocorticoids, Ginkgo biloba, and mometasone furoate nasal spray.

Design  Randomized trial.

Setting  Academic research.

Patients  Seventy-one patients who were diagnosed as having postviral olfactory loss.

Main Outcome Measures  All patients underwent olfactory function tests, including the butanol threshold test (BTT) and the cross-cultural smell identification test (CCSIT), and follow-up tests were performed 4 weeks later. In the interim, 28 patients were treated with prednisolone for 2 weeks (monotherapy), and the other 43 patients were treated with prednisolone for 2 weeks plus G biloba for 4 weeks (combination therapy). All patients used mometasone nasal spray twice daily for 4 weeks.

Results  Scores on the BTT and CCSIT significantly increased after treatment in both groups (P < .001 for both). The mean (SD) BTT score changes were 1.4 (2.2) in the monotherapy group and 2.2 (2.9) in the combination therapy group (P = .22). The mean (SD) CCSIT score changes were 0.9 (1.7) in the monotherapy group and 1.9 (2.7) in the combination therapy group (P = .11). On the BTT, the treatment response (defined as a score increase of ≥3) rates were 32% (9 of 28) in the monotherapy group and 37% (16 of 43) in the combination therapy group (P = .66), and the odds ratio was 1.25 (95% confidence interval, 0.46-3.42). On the CCSIT, the treatment response rates were 14% (4 of 28) in the monotherapy group and 33% (14 of 43) in the combination therapy group (P = .08), and the odds ratio was 2.89 (95% confidence interval, 0.84-9.97).

Conclusions  Olfactory function in patients with postviral olfactory loss was significantly improved by both treatment modalities. Although the treatment response was not statistically different between the monotherapy group and the combination therapy group, the addition of G biloba showed a tendency of greater efficacy in the treatment of postviral olfactory loss.

  S. H Hwang , D. J Park , Y. S Jee , M. C Kim , H. H Kim , H. J Lee , H. K Yang and K. U. Lee
 

Objective  To analyze 3-year actual disease-free survival after laparoscopy-assisted gastrectomy for gastric cancer on the assumption that 3-year disease-free survival may represent 5-year overall survival.

Design  Retrospective analysis.

Setting  Department of surgery of a university hospital.

Patients  A total of 197 patients who underwent laparoscopy-assisted gastrectomy for gastric cancer from May 1998 to September 2007 and who were followed up for more than 3 years.

Main Outcome Measures  Feasibility and long-term survival rate with survival analysis by the Kaplan-Meier method.

Results  Subtotal and total gastrectomies were performed in 178 and 19 patients, respectively. The scope of the lymph node dissections were D1 + β (n = 152) and D2 (n = 45). There were 153, 28, 8, 6, 1, and 1 patients in stages Ia, Ib, II, IIIa, IIIb, and IV, respectively. The median follow-up was 45 months (range, 1-113 months), and there were 7 recurrences. Multivariate analysis of disease-specific survival showed that depth of invasion and lymph node metastasis influenced the prognosis independently. The actual 3-year disease-free survival rate for all patients was 96.9%. The 173 patients with early gastric cancer and 24 with advanced gastric cancer showed 98.8% and 79.1% actual 3-year disease-free survival rates, respectively.

Conclusions  Laparoscopy-assisted gastrectomy is acceptable oncologically in early gastric cancer if 3-year disease-free survival represents 5-year overall survival. Laparoscopy-assisted gastrectomy may also play an important role in the treatment of advanced gastric cancer.

  H. J Lee , K. S Kim , J. S Jeong , M. A Cheong and J. C. Shim
  Background

The purpose of this study was to verify which muscle among the adductor pollicis (AP), orbicularis oculi (OO), and corrugator supercilii (CS) is a better predictor of optimal intubating conditions after administration of rocuronium.

Methods

In this prospective trial, 201 patients were randomized into six groups to receive rocuronium at a dose of 0.6 or 1.0 mg kg–1 during propofol–remifentanil–nitrous oxide anaesthesia. The tracheal intubation was performed after maximal neuromuscular block by acceleromyography at the thumb (AP), the eyelid (OO), and the superciliary arch (CS). The onset time, intubating conditions, peak vital signs, and bispectral index were assessed.

Results

The onset time of rocuronium in the OO and CS muscle was significantly shorter than in the AP muscle (P<0.001), but excellent intubating conditions were significantly increased in the AP (87%) and the CS (77%) compared with the OO (32%) after a dose of 0.6 mg kg–1 of rocuronium (P<0.05).

Conclusions

After administration of rocuronium, twitch monitoring at the OO allows a faster intubation but is associated with an unacceptable incidence of inadequate intubating conditions. Excellent intubating conditions are observed most frequently with AP monitoring but with the longest delay before intubation is attempted. Monitoring of the CS allows intubation earlier than that of AP with fewer patients having excellent but no patients having inadequate intubating conditions.

  M. W Suh , H. J Lee , J. S Kim , C. K Chung and S. H. Oh
 

Speechreading is a visual communicative skill for perceiving speech. In this study, we tested the effects of speech experience and deafness on the speechreading neural network in normal hearing controls and in two groups of deaf patients who became deaf either before (prelingual deafness) or after (postlingual deafness) auditory language acquisition. Magnetic signals from the cerebral cortex were recorded using a 306-channel magnetoencephalographic system. During magnetoencephalographic measurements, subjects were asked to perform a speechreading task from video clips of a female speaker either pronouncing syllables (speechreading condition) or showing closed-mouth movement. The sources of the evoked fields were modelled using equivalent current dipoles, the origins of which were fitted to the intracranial space based on magnetic resonance imaging findings. During the speechreading condition, the latency of auditory cortex activation was shorter in the postlingual deafness group than in the normal hearing control group. This parameter negatively correlated with speechreading scores measured clinically. Furthermore, as the duration of deafness increased, the latency of auditory cortex activation decreased exponentially. However, no such correlation was found in the prelingual deafness group which differed significantly from the two other groups in this respect. The latency of auditory cortex activation was significantly longer in the prelingual deafness group than in the two other groups. Thus, auditory experience may be crucial for the development of a normal neural network for speechreading. The pre-existing speechreading network in the postlingual deafness group is made more efficient by speeding up the neural response.

  S Paul , A. M Rimando , H. J Lee , Y Ji , B. S Reddy and N. Suh
 

Oxidative/nitrosative stress and generation of proinflammatory cytokines are hallmarks of inflammation. Because chronic inflammation is implicated in several pathologic conditions in humans, including cancers of the colon, anti-inflammatory compounds may be useful chemopreventive agents against colon cancer. Stilbenes, such as resveratrol, have diverse pharmacologic activities, which include anti-inflammation, cancer prevention, a cholesterol-lowering effect, enhanced insulin sensitivity, and increased life span. We previously showed that pterostilbene (trans-3,5-dimethoxy-4'-hydroxystilbene), a structural analogue of resveratrol, is present in blueberries and that pterostilbene inhibited expression of certain inflammation-related genes in the colon and suppressed aberrant crypt foci formation in rats. Here, we examined molecular mechanisms of the action of pterostilbene in colon cancer. Pterostilbene reduced cell proliferation, down-regulated the expression of c-Myc and cyclin D1, and increased the level of cleaved poly(ADP-ribose) polymerase. A combination of cytokines (tumor necrosis factor-, IFN-, and bacterial endotoxin lipopolysaccharide) induced inflammation-related genes such as inducible nitric oxide synthase and cyclooxygenase-2, which was significantly suppressed by treatment with pterostilbene. We further identified upstream signaling pathways contributing to the anti-inflammatory activity of pterostilbene by investigating multiple signaling pathways, including nuclear factor-B, Janus-activated kinase-signal transducer and activator of transcription, extracellular signal-regulated kinase, p38, c-Jun NH2-terminal kinase, and phosphatidylinositol 3-kinase. Cytokine induction of the p38-activating transcription factor 2 pathway was markedly inhibited by pterostilbene among the different mediators of signaling evaluated. By silencing the expression of the p38 isoform, there was significant reduction in cytokine induction of inducible nitric oxide synthase and cyclooxygenase-2. Our data suggest that the p38 mitogen-activated protein kinase cascade is a key signal transduction pathway for eliciting the anti-inflammatory action of pterostilbene in cultured HT-29 colon cancer cells.

  K. M Lee , K. W Lee , S Byun , S. K Jung , S. K Seo , Y. S Heo , A. M Bode , H. J Lee and Z. Dong
 

Nontoxic small molecules with multitargeting effects are believed to have potential in cancer prevention. Dietary phytochemicals were shown to exhibit cancer-preventive effects attributed to their antioxidant capacities. In this report, we show that the natural compound 5-deoxykaempferol (5-DK) exerts a chemopreventive effect on UVB-induced skin carcinogenesis by targeting multiple signaling molecules. 5-DK suppressed the UVB-induced expression of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor in mouse skin epidermal JB6 P+ cells. Moreover, 5-DK inhibited phosphorylation of MKK3/6, MKK4, and Akt, but had no effect on phosphorylation of Src, extracellular signal–regulated kinases, or ribosomal S6 kinase (RSK). However, 5-DK affected multiple targets by reducing Src, phosphoinositide 3-kinase (PI3K), and RSK2 activities. In particular, pull-down assays revealed that 5-DK specifically bound to and competed with ATP for binding with Src, PI3K, and RSK2. Exposure to 5-DK significantly suppressed UVB-induced tumorigenesis in mouse skin in a dose-dependent manner, and it inhibited the UVB-induced expression of COX-2, proliferating cell nuclear antigen, vascular endothelial growth factor, and matrix metalloproteinase-9. Our data suggest that 5-DK docks at the ATP-binding site of Src, PI3K, and RSK2. For RSK2, the ATP-binding site is located between the N- and C-lobes of the kinase domain. Taken together, our results indicate that 5-DK holds promise for the treatment of UVB-induced skin cancer by targeting Src, PI3K, and RSK2 signaling. Cancer Prev Res; 3(4); 454–65. ©2010 AACR.

  H. O Byun , N. K Han , H. J Lee , K. B Kim , Y. G Ko , G Yoon , Y. S Lee , S. I Hong and J. S. Lee
 

Induction of premature senescence may be a promising strategy for cancer treatment. However, biomarkers for senescent cancer cells are lacking. To identify such biomarkers, we performed comparative proteomic analysis of MCF7 human breast cancer cells undergoing cellular senescence in response to ionizing radiation (IR). IR-induced senescence was associated with up-regulation of cathepsin D (CD) and down-regulation of eukaryotic translation elongation factor 1β2 (eEF1B2), as confirmed by Western blot. The other elongation factor, eukaryotic translation elongation factor 11 (eEF1A1), was also down-regulated. IR-induced senescence was associated with similar changes of CD and eEF1 (eEF1A1 and eEF1B2) levels in the HCT116 colon cancer cell line and the H460 lung cancer cell line. Up-regulation of CD and down-regulation of eEF1 seemed to be specific to senescence, as they were observed during cellular senescence induced by hydrogen peroxide or anticancer drugs (camptothecin, etoposide, or 50 ng doxorubicin) but not during apoptosis induced by Taxol or 10 µg doxorubicin or autophagy induced by tamoxifen. The same alterations in CD and eEF1A1 levels were observed during replicative senescence and Ras oncogene-induced senescence. Transient cell cycle arrest did not alter levels of eEF1 or CD. Chemical inhibition of CD (pepstatin A) and small interfering RNA–mediated knockdown of CD and eEF1 revealed that these factors participate in cell proliferation. Finally, the senescence-associated alteration in CD and eEF1 levels observed in cell lines was also observed in IR-exposed xenografted tumors. These findings show that CD and eEF1 are promising markers for the detection of cellular senescence induced by a variety of treatments. [Cancer Res 2009;69(11):4638–47]

  S Paul , A. J DeCastro , H. J Lee , A. K Smolarek , J. Y So , B Simi , C. X Wang , R Zhou , A. M Rimando and N. Suh
 

Stilbenes are phytochemicals present in grapes, berries, peanuts and red wine. A widely studied stilbene, resveratrol (trans-3,5,4'-trihydroxystilbene), has been shown to exert antioxidant, anti-inflammatory, chemopreventive and antiaging effects in a number of biological systems. We reported earlier that pterostilbene (trans-3,5-dimethoxy-4'-hydroxystilbene), a structurally related stilbene found in blueberries, was effective in reducing the incidence and multiplicity of aberrant crypt foci formation in the colon of rats injected with azoxymethane (AOM). Our present study was to identify the chemopreventive potential of pterostilbene with colonic tumor formation as an end point and further to evaluate the mechanistic action of pterostilbene during colon carcinogenesis. F344 rats were given two AOM injections subcutaneously when they were 7 and 8 weeks old and continuously fed the control or 40 p.p.m. pterostilbene diet for 45 weeks. Overall analyses indicated that pterostilbene reduced colon tumor multiplicity of non-invasive adenocarcinomas, lowered proliferating cell nuclear antigen and downregulated the expression of β-catenin and cyclin D1. Pterostilbene decreased mucosal levels of the proinflammatory cytokines, tumor necrosis factor-, interleukin (IL)-1β and IL-4. Colon tumors from pterostilbene-fed animals showed reduced expression of inflammatory markers as well as nuclear staining for phospho-p65, a key molecule in the nuclear factor-kappaB pathway. In HT-29 cells, pterostilbene reduced the protein levels of β-catenin, cyclin D1 and c-MYC, altered the cellular localization of β-catenin and inhibited the phosphorylation of p65. Our data with pterostilbene in suppressing colon tumorigenesis, cell proliferation as well as key inflammatory markers in vivo and in vitro suggest the potential use of pterostilbene for colon cancer prevention.

  H. J Lee , J Ju , S Paul , J. Y So , A DeCastro , A Smolarek , M. J Lee , C. S Yang , H. L Newmark and N. Suh
 

Purpose: Tocopherols are lipophilic antioxidants present in vegetable oils. Although the antioxidant and anticancer activities of -tocopherol (vitamin E) have been studied for decades, recent intervention studies with -tocopherol have been negative for protection from cancer in humans. The tocopherols consist of four isoforms, which are the , β, , and variants, and recent attention is being given to other isoforms. In the present study, we investigated the inhibitory effect of a tocopherol mixture rich in - and -tocopherols against mammary tumorigenesis.

Experimental Design: Female Sprague Dawley rats were treated with N-methyl-N-nitrosourea (NMU), and then fed diets containing 0.1%, 0.3%, or 0.5% mixed tocopherols rich in - and -tocopherols for 9 weeks. Tumor burden and multiplicity were determined, and the levels of markers of inflammation, proliferation, and apoptosis were evaluated in the serum and in mammary tumors. The regulation of nuclear receptor signaling by tocopherols was studied in mammary tumors and in breast cancer cells.

Results: Dietary administration of 0.1%, 0.3%, or 0.5% mixed tocopherols suppressed mammary tumor growth by 38%, 50%, or 80%, respectively. Tumor multiplicity was also significantly reduced in all three mixed tocopherol groups. Mixed tocopherols increased the expression of p21, p27, caspase-3, and peroxisome proliferator activated receptor-, and inhibited AKT and estrogen signaling in mammary tumors. Our mechanistic study found that - and -tocopherols, but not -tocopherol, activated peroxisome proliferator activated receptor- and antagonized estrogen action in breast cancer.

Conclusion: The results suggest that - and -tocopherols may be effective agents for the prevention of breast cancer.

  J Lee , H. J Lee and C. Lee
 

As the integration scale of a chip increases, on-chip interconnects suffer from the increased area occupied by a large number of bus signals. To reduce the overhead for communication, this paper formulates a new concept of an on-chip communication approach, called phase-based interconnection, with an example protocol, system-on-chip network protocol (SNP). In the phase-based communication, a small number of signals called phase signals are used to distinguish the types of signals transmitted through the main communication channel. To identify transactions transmitted through the channel, the SNP protocol defines the allowed sequence of phases for each transaction. A theoretical framework provides conditions for a phase-based protocol to allow immediate decoding of transactions. Simulation results show that the bandwidth of SNP is greater than that of a de facto standard bus protocol although SNP has wires only about three-fifths of the standard bus protocol. Although the signal-toggling rate is increased because of the multiplexed transmission of various signals through a single communication channel, simulation results show that the increase is not significant for multimedia applications that frequently transmit burst transfers. The phase omission of SNP helps to reduce the transaction failure rate to 65% while the hardware implementation cost for the support of phase omission is negligible.

  H. J Kim , H. J Lee , H Kim , S. W Cho and J. S. Kim
 

Broad applications of zinc finger nuclease (ZFN) technology—which allows targeted genome editing—in research, medicine, and biotechnology are hampered by the lack of a convenient, rapid, and publicly available method for the synthesis of functional ZFNs. Here we describe an efficient and easy-to-practice modular-assembly method using publicly available zinc fingers to make ZFNs that can modify the DNA sequences of predetermined genomic sites in human cells. We synthesized and tested hundreds of ZFNs to target dozens of different sites in the human CCR5 gene—a co-receptor required for HIV infection—and found that many of these nucleases induced site-specific mutations in the CCR5 sequence. Because human cells that harbor CCR5 null mutations are functional and normal, these ZFNs might be used for (1) knocking out CCR5 to produce T-cells that are resistant to HIV infection in AIDS patients or (2) inserting therapeutic genes at "safe sites" in gene therapy applications.

  H. J Lee , E Kim and J. S. Kim
 

We present a novel approach for generating targeted deletions of genomic segments in human and other eukaryotic cells using engineered zinc finger nucleases (ZFNs). We found that ZFNs designed to target two different sites in a human chromosome could introduce two concurrent DNA double-strand breaks (DSBs) in the chromosome and give rise to targeted deletions of the genomic segment between the two sites. Using this method in human cells, we were able to delete predetermined genomic DNA segments in the range of several-hundred base pairs (bp) to 15 mega-bp at frequencies of 10–3 to 10–1. These high frequencies allowed us to isolate clonal populations of cells, in which the target chromosomal segments were deleted, by limiting dilution. Sequence analysis revealed that many of the deletion junctions contained small insertions or deletions and microhomologies, indicative of DNA repair via nonhomologous end-joining. Unlike other genome engineering tools such as recombinases and meganucleases, ZFNs do not require preinsertion of target sites into the genome and allow precise manipulation of endogenous genomic scripts in animal and plant cells. Thus, ZFN-induced genomic deletions should be broadly useful as a novel method in biomedical research, biotechnology, and gene therapy.

  H. J Lee , M Gallagher and P. C. Holland
 

The central amygdala nucleus (CeA) plays a critical role in cognitive processes beyond fear conditioning. For example, intact CeA function is essential for enhancing attention to conditioned stimuli (CSs). Furthermore, this enhanced attention depends on the CeA's connections to the nigrostriatal system. In the current study, we examined the role of the CeA's connections to two midbrain dopamine regions, the substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA), in processing CS information when predictions of reward or nonreward were confirmed or disconfirmed. Initially, two different retrograde tracers were injected into the SNc and the VTA of rats, to label CeA cells. Different groups of rats then received a visual CS either paired or unpaired with food. Finally, Fos induction was assessed after a test session in which rats were exposed to the visual CS alone or paired with food. Colabeling of Fos and the retrograde tracer(s) showed that CeA neurons projecting to the SNc, but not to the VTA, were engaged in processing CS information when the training and testing conditions differed. These results suggest that the CeA–nigral pathway represents prediction error information during appetitive conditioning.

  H. N Hilton , M Kalyuga , M. J Cowley , M. C Alles , H. J Lee , C. E Caldon , K Blazek , W Kaplan , E. A Musgrove , R. J Daly , M. J Naylor , J. D Graham , C. L Clarke and C. J. Ormandy
 

Prolactin and progesterone act together to regulate mammary alveolar development, and both hormones have been implicated in breast cancer initiation and progression. Here we show that Elf5, a prolactin-induced ETS transcription factor that specifies the mammary secretory cell lineage, is also induced by progestins in breast cancer cells via a direct mechanism. To define the transcriptional response to progestin elicited via Elf5, we made an inducible Elf5 short hairpin-RNA knock-down model in T47D breast cancer cells and used it to prevent the progestin-induction of Elf5. Functional analysis of Affymetrix gene expression data using Gene Ontologies and Gene Set Enrichment Analysis showed enhancement of the progestin effects on cell cycle gene expression. Cell proliferation assays showed a more efficacious progestin-induced growth arrest when Elf5 was kept at baseline levels. These results showed that progestin induction of Elf5 expression tempered the antiproliferative effects of progestins in T47D cells, providing a further mechanistic link between prolactin and progestin in the regulation of mammary cell phenotype.

  I C Cheng , H. J Lee and T. C. Wang
 

Sf9, a lepidopteran cell line isolated from the fall armyworm, Spodoptera frugiperda, was shown to be significantly more resistant to growth inhibition and apoptosis induction effects of x-ray irradiation than several human cell lines of different origins. The single-cell electrophoresis technique revealed that Sf9 cells showed lower x-ray irradiation-induced DNA damage as well as better efficiency at repairing these damages. In addition, Sf9 cells were lower in both background and x-ray irradiation-induced intracellular oxidative stress, in which the higher intracellular level of reduced glutathione seemed to play a major role. The significance of oxidative stress in determining the radioresistance of Sf9 cells was confirmed by their being more resistant to hydrogen peroxide while equally susceptible to other non-reactive oxygen species of N-nitroso alkylating agents when compared with a human cell line. Although the Sf9 and human cell lines were equally susceptible to the lethal effects of N-nitroso alkylating agents, the components of DNA damage-induced and the repair enzymes involved significantly differ. This phenomenon is also discussed in this report.

 
 
 
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