BCAS2 promotes prostate cancer cells proliferation by enhancing AR mRNA transcription and protein stability

BACKGROUND

We showed previously that breast carcinoma amplified sequence 2 (BCAS2) functions as a negative regulator of p53. We also found that BCAS2 is a potential AR-associated protein. AR is essential for the growth and survival of prostate carcinoma. Therefore we characterised the correlation between BCAS2 and AR.

METHODS

Protein interactions were examined by GST pull-down assay and co-immunoprecipitation. Clinical prostate cancer (PCa) specimens were evaluated by immunohistochemical assay. AR transcriptional activity and LNCaP cell growth were assessed by luciferase assay and MTT assay, respectively.

RESULTS

BCAS2 expression was significantly increased in PCa. BCAS2 stabilised AR protein through both hormone-dependent and -independent manners. There are at least two mechanisms for BCAS2-mediated AR protein upregulation: One is p53-dependent. The p53 is suppressed by BCAS2 that results in increasing AR mRNA and protein expression. The other is via p53-independent inhibition of proteasome degradation. As BCAS2 can form a complex with AR and HSP90, it may function with HSP90 to stabilise AR protein from being degraded by proteasome.

CONCLUSIONS

In this study, we show that BCAS2 is a novel AR-interacting protein and characterise the correlation between BCAS2 and PCa. Thus we propose that BCAS2 could be a diagnostic marker and therapeutic target for PCa.

Abstract OT1-4-04: A phase II randomized, open-label, neoadjuvant study of LCL161, an oral antagonist of inhibitor of apoptosis proteins, in combination with paclitaxel in patients with triple-negative breast cancer

Background: Inhibitor of apoptosis proteins (IAPs) negatively regulate cell death through a variety of mechanisms. LCL161 is an oral small-molecule antagonist of IAPs that has demonstrated single-agent activity and synergy with paclitaxel in breast cancer tumor models. In preclinical studies, a gene expression signature has been shown to enrich for response to LCL161. The recommended dose of LCL161 1800 mg once weekly has demonstrated preliminary antitumor activity with paclitaxel in an ongoing Phase Ib study in patients with breast cancer.

Trial design: This is a Phase II, randomized, open-label study of neoadjuvant paclitaxel with or without LCL161 in women with operable, newly diagnosed triple-negative breast cancer (NCT01617668). Key inclusion criteria include women with histologically confirmed diagnosis of triple-negative breast cancer; clinical stages T2, N0–N2, M0; candidates for mastectomy or breast-conserving surgery; ECOG performance status ≤1; known status of the LCL161-predictive gene expression signature (positive and negative gene signature is a stratification factor); and adequate bone marrow and organ function. Key exclusion criteria are: bilateral or inflammatory breast cancer; locally recurrent breast cancer; patients currently receiving systemic therapy for any other malignancy, or having received systemic therapy for a malignancy in the preceding 3 months; impaired gastrointestinal function that may affect the absorption of LCL161; or uncontrolled cardiac disease.

Patients are randomized 1:1 to receive paclitaxel IV (80 mg/m2 weekly) with or without oral LCL161 (1800 mg once weekly) for 12 weeks (corresponding to 4 treatment cycles). Each treatment arm is stratified 1:1 based on gene expression signature status (positive or negative).

Endpoints: The primary endpoint is pathologic complete response (pCR), defined as the absence of invasive disease in the breast after 12 weeks of therapy, analyzed separately in the gene expression signature positive and negative groups. The key secondary endpoint is the pCR rate following treatment with LCL161 and paclitaxel in gene expression signature-positive or -negative tumors. Other secondary endpoints include: pCR rate in breast after 12 weeks of therapy in the full study population, and in patients with gene expression signature-positive and -negative tumors treated with paclitaxel alone; pCR rate in breast, regional nodes and axilla; biomarker evaluation including caspase 3 activation in tumor; safety; and pharmacokinetics of LCL161.

Statistical methods: pCR analysis will be performed according to treatment group and gene expression signature status. An absolute increase of at least 7.5% in pCR rate of the experimental arm over the control arm will be considered as evidence of clinically relevant efficacy.

Target accrual: Approximately 200 patients will be randomized into this study. Recruitment is ongoing across America, Europe, and Asia.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT1-4-04.

Abstract P3-06-02: Genetic polymorphisms from genome-wide association study associated with the metabolic and cell proliferation pathways affect the time to distant metastases of hormone receptor-positive and Her2-negative early breast cancer

Background: Single nucleotide polymorphisms (SNPs) identified from genome-wide association study (GWAS) have been found to be associated with breast cancer risk. We hypothesized that candidate genes and genes derived from GWAS involving in the Estrone/Estradiol (E2)/Tamoxifen biosynthesis may influence the adjuvant hormonal therapy effect and the survival. In this study, we sought to investigate whether these SNPs are associated with prognosis of hormone receptor (HR)-positive breast cancer patients, especially in HER2-negative patients.

Patients and methods: We selected breast cancer susceptibility SNPs identified by GWAS, SNPs in tamoxifen metabolizing related genes, and SNPs in estrogen receptor genes and estrogen metabolism genes, and genotyped for variations of above genes, including ALDH3A1, CYP2C19, COMT, CYP19, MAP3K1, FGFR2, TNRC9, HCN1, ERCC4, CYP3A5, UGT1A1, ER, ABCG2, CYP2B6, CYP2D6, 5p12 in 171 hormone receptor-positive, and Her2-negative early breast cancer patients (127 with negative lymph node [LN], and 44 with 1–3 positive LN). All patients received adjuvant hormonal therapy. The associations were examined between SNPs and distance disease-free survival (DDFS), and overall survival (OS) by using the log-rank test and Cox's proportional hazard model. Furthermore, we combined clinicopathologic features and SNPs into the risk score analysis to further validate above identified genetic markers.

Results: We found that SNPs of CYP2B6 (rs3211371), FGFR2 (rs2981582), and MAP3K1 (rs889312) were significantly associated with DDFS and OS. Furthermore, in lymph node-negative patients, CYP2B6 (rs3211371), FGFR2 (rs2981582), MAP3K1 (rs889312) and 5p12 (rs10941679 and rs4415084) were significantly associated with DDFS and OS, while CYP3A5 (rs776746) was significantly associated with OS but not DDFS. We further assessed the associations of disease prognosis with the number of high-risk genotypes in CYP3A5, FGFR2, and MAP3K1, and showed significant dose-response relationships between the number of high-risk alleles at these 3 loci and DDFS (P = 0.005 for trend) and OS (P = 0.0008 for trend). When combining the clinicopathologic features and SNPs into the risk score analysis, patients were divided into 3 subgroups (subgroup 1, risk score<-1.438, n=43 [LN-positive, n=7]; subgroup 2, risk score between −1.438 and 1.708, n=85 [LN-positive, n=26]; subgroup 3, risk score>1.708, n=43 [LN-positive, n=11]). We found that around 20 % of subgroup 3 patients had early development of distant metastases (DM) in the upfront 3 years (the trend of DM appeared to persist at least 10 years), and subgroup 2 patients had higher risk of DM after 5 years, whereas subgroup 1 patients had no development of DM even after 12 years.

Conclusion: Our results indicate that in addition to drug metabolic genes, genes related to cell proliferation, anti-apoptosis, and signaling transduction, for example, CYP3A5, CYP2B6, FGFR2, and MAP3K1 genes were associated with DDFS and OS in HR-positive/Her2-negative breast cancer patients. These findings provide additional insight that the genetic variants, or host factors, may affect the prognosis of breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-02.

Abstract OT1-1-17: LUX-Breast 2: Phase II, open-label study of oral afatinib in HER2-overexpressing metastatic breast cancer (MBC) patients (pts) who progressed on prior trastuzumab and/or lapatinib*

Background: Management of HER2-overexpressing MBC has improved over the past decade. However, pts still develop resistance to currently available HER2-targeted therapies and novel effective treatments are increasingly required as dual targeted combinations are given in early treatment lines already. Current therapies focus on targeting HER2 and do not inhibit all relevant ErbB Family dimers. Afatinib is an oral, irreversible ErbB Family Blocker that inhibits signaling through activated EGFR (ErbB1), HER2 (ErbB2) and ErbB4 receptors and transphosphorylation of ErbB3. Preclinical studies have demonstrated efficacy in trastuzumab-sensitive, and trastuzumab-resistant human BC xenograft models dependent on ErbB signaling. Efficacy of afatinib in a trastuzumab-resistant SUM190 xenograft model has been shown to be increased by addition of intravenous (i.v.) vinorelbine. Afatinib monotherapy has shown promising clinical benefit in 46% of HER2-overexpressing MBC pts who progressed on prior trastuzumab, with 10% of pts achieving a partial response.1

Methods: This open-label Phase II trial (NCT01271725) investigates efficacy and safety of afatinib alone (40 mg/day) followed by afatinib ‘beyond progression’ in combination with chemotherapy in 120 pts with HER2-overexpressing MBC, who progressed on prior neoadjuvant and/or adjuvant trastuzumab and/or lapatinib. Pts who progress on afatinib monotherapy receive afatinib + either weekly paclitaxel 80 mg/m2 or vinorelbine i.v. 25 mg/m2. Eligible pts have confirmed HER2-overexpressing BC, Stage IV disease measurable by RECIST 1.1, progressed on trastuzumab and/or lapatinib therapy in either neoadjuvant and/or adjuvant setting, are eligible for retreatment with paclitaxel (i.e. should not have been pretreated with paclitaxel within the past 12 months), or are eligible for treatment with vinorelbine (i.e. should not have been pretreated with vinorelbine). Exclusion criteria include inadequate cardiac, renal, hepatic and hematological function, pre-existing gastrointestinal dysfunction, rapidly progressing visceral MBC, interstitial lung disease, and active brain metastases. The primary endpoint is objective response (OR) and secondary endpoints include best overall response, duration of OR, progression-free survival (PFS) and safety. PFS and safety will be assessed separately for afatinib mono- and combination therapy. An early stopping rule was deployed to minimize the number of pts treated should afatinib be ineffective; once 20 evaluable pts (according to RECIST 1.1) completed at least two courses of afatinib (or progressed during the first course), a meeting was held to evaluate the objective tumor response rate and to decide whether to proceed with the trial or stop due to futility. If at least one unconfirmed OR had been witnessed from all available information at the time, then the trial was to continue to full accrual. This early stopping rule for futility has been passed and the trial will continue to full accrual. Pt enrollment began in May 2011 in ∼40 sites and five countries.

1. Lin NU, et al. Breast Cancer Res Treat 2012. DOI: 10.1007/s10549-012-2003-y.

*Updated abstract from ASCO 2012.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT1-1-17.

Diffusion Tensor Imaging for Predicting Hand Motor Outcome in Chronic Stroke Patients

OBJECTIVE: Previous studies have indicated that diffusion tensor imaging (DTI) values are related to clinical outcome in stroke patients. This prospective study explored whether DTI values were predictive for hand function outcome in chronic stroke patients. METHODS: The DTI parameters (rλ1, rλ23, fractional anisotropy [rFA] and mean diffusivity [rMD]) were investigated in patients with completely paralysed hands (CPH; n = 10) or partially paralysed hands (PPH; n = 10), by two methods of analysis: segment of the corticospinal tract [sCST] analysis; pure region of interest [ROI] analysis. Spearman's correlation coefficient was used to assess the correlation between the DTI parameters and the following clinical measures: Fugl—Meyer Assessment [FMA]; National Institutes of Health Stroke Scale [NIHSS]. RESULTS: Significant differences were found between CPH and PPH for rFA and rλ23 (sCST analysis) and for rMD and rλ23 (ROI analysis). The rλ23 (sCST analysis) correlated with the NIHSS; the rMD (sCST analysis) correlated with the FMA (hand). CONCLUSION: The three parameters, rFA, rλ23 and rMD may have predictive value for evaluating hand function outcome in chronic stroke patients.

Lack of efficacy to systemic chemotherapy for treatment of metaplastic carcinoma of the breast in the modern era

Metaplastic carcinoma of the breast (MCB) is a rare subtype of breast cancer. Anecdotal reports are available regarding its response to systemic chemotherapy. We reviewed the records of patients diagnosed with MCB at National Taiwan University Hospital between 1988 and 2009. A total of 46 MCB cases were identified from 8,695 breast tumor patients who underwent biopsy or resection. About 11 of 25 patients with initial bulky disease (T3-4) received neoadjuvant chemotherapy before surgery, and 2 (18.2%) exhibited a partial response. About 12 of 18 patients who developed distant metastasis received palliative systemic chemotherapy. Of them, only 1 (8.3%), 1 (10%), and none (0%) responded to first-, second-, or third- and beyond line chemotherapy, respectively. None of the patients who received anthracyline- (n = 13), vinorelbine- (n = 7), or cyclophosphamide-based (n = 18) chemotherapy responded, whereas 3 (17.6%) of 17 patients who received taxane-based chemotherapy exhibited a partial response. Tumor response to systemic chemotherapy remains generally poor for MCB patients. Taxanes may have modest activity, but need to be validated in further studies.

Surgery-first accelerated orthognathic surgery: postoperative rapid orthodontic tooth movement

PURPOSE

Clinically, we have observed the phenomenon of postoperatively accelerated orthodontic tooth movement in patients who had orthognathic surgery. This phenomenon lasts for a period of 3 to 4 months. However, the underlying mechanisms of this phenomenon have not been well studied yet. The purpose of this prospective clinical pilot study was to study the postoperative changes in bone physiology and metabolism and the corresponding responses in the dentoalveolus, such as the changes in tooth mobility.

MATERIALS AND METHODS

Twenty-two consecutive adult patients who had 2-jaw orthognathic surgery were included in this study. The levels of serum alkaline phosphatase and C-terminal telopeptide of type I collagen (ICTP), as well as the tooth mobility of the maxillary and mandibular incisors based on the Periotest method (Siemens AG, Bensheim, Germany), were examined preoperatively and 1 week, 1 month, 2 months, 3 months, and 4 months postoperatively. The data were analyzed statistically.

RESULTS

Both tooth mobility of the maxillary and mandibular incisors and ICTP significantly increased from 1 week to 3 months postoperatively and then decreased to their preoperative levels in the fourth month postoperatively. The changes in tooth mobility were significantly in correspondence with the changes in ICTP. The alkaline phosphatase level significantly increased from the first to fourth month postoperatively, but it was not significantly correlated to the changes in tooth mobility.

CONCLUSION

The orthognathic surgery triggers a 3- to 4-month period of higher osteoclastic activities and metabolic changes in the dentoalveolus postoperatively, which possibly accelerates postoperative orthodontic tooth movement.

Multicolor fluorescence enhancement from a photonics crystal surface

A photonic crystal substrate exhibiting resonant enhancement of multiple fluorophores has been demonstrated. The device, fabricated uniformly from plastic materials over a ∼3×5 in.(2) surface area by nanoreplica molding, utilizes two distinct resonant modes to enhance electric field stimulation of a dye excited by a λ=632.8 nm laser (cyanine-5) and a dye excited by a λ=532 nm laser (cyanine-3). Resonant coupling of the laser excitation to the photonic crystal surface is obtained for each wavelength at a distinct incident angle. Compared to detection of a dye-labeled protein on an ordinary glass surface, the photonic crystal surface exhibited a 32× increase in fluorescent signal intensity for cyanine-5 conjugated streptavidin labeling, while a 25× increase was obtained for cyanine-3 conjugated streptavidin labeling. The photonic crystal is capable of amplifying the output of any fluorescent dye with an excitation wavelength in the 532 nm<λ<633 nm range by selection of an appropriate incident angle. The device is designed for biological assays that utilize multiple fluorescent dyes within a single imaged area, such as gene expression microarrays.

Dynamic seizure-related changes in extracellular signal-regulated kinase activation in a mouse model of temporal lobe epilepsy

Extracellular signal-regulated kinase (ERK) is highly sensitive to regulation by neuronal activity and is critically involved in several forms of synaptic plasticity. These features suggested that alterations in ERK signaling might occur in epilepsy. Previous studies have described increased ERK phosphorylation immediately after the induction of severe seizures, but patterns of ERK activation in epileptic animals during the chronic period have not been determined. Thus, the localization and abundance of phosphorylated extracellular signal-regulated kinase (pERK) were examined in a pilocarpine model of recurrent seizures in C57BL/6 mice during the seizure-free period and at short intervals after spontaneous seizures. Immunolabeling of pERK in control animals revealed an abundance of distinctly-labeled neurons within the hippocampal formation. However, in pilocarpine-treated mice during the seizure-free period, the numbers of pERK-labeled neurons were substantially decreased throughout much of the hippocampal formation. Double labeling with a general neuronal marker suggested that the decrease in pERK-labeled neurons was not due primarily to cell loss. The decreased ERK phosphorylation in seizure-prone animals was interpreted as a compensatory response to increased neuronal excitability within the network. Nevertheless, striking increases in pERK labeling occurred at the time of spontaneous seizures and were evident in large populations of neurons at very short intervals (as early as 2 min) after detection of a behavioral seizure. These findings suggest that increased pERK labeling could be one of the earliest immunohistochemical indicators of neurons that are activated at the time of a spontaneous seizure.

Antioxidant and pro-oxidant properties of chlorhexidine and its interaction with calcium hydroxide solutions

AIM

To evaluate the antioxidant and pro-oxidant properties of chlorhexidine (CHX).

METHODOLOGY

The scavenging and generation of reactive oxygen species (ROS) by CHX in the presence or absence of saturated Ca(OH)(2) solutions was evaluated. The reaction emitted chemiluminescence in the presence of lucigenin thus was determined by a luminometer to evaluate the levels of ROS production. Changes in DNA conformation were analysed by agarose gel electrophoresis. Paired Student's t-test was used to compare the difference between groups.

RESULTS

Chlorhexidine (0.00002-0.02%) effectively scavenged 56-88% of the superoxide radicals generated by the xanthine/xanthine oxidase reaction. Through analysis of PUC18 DNA conformation changes, CHX was shown to be a mild scavenger of hydroxyl radicals generated by H(2)O(2) plus FeCl(2). However, CHX (>0.083%) decreased the mobility of PUC18 plasmid DNA with potential production of DNA-DNA cross-link and severe DNA breaks (presence of DNA smear) at further higher concentrations. Furthermore, CHX induced ROS production including H(2)O(2) and superoxide radicals in 0.1N NaOH (pH = 12.76) or Ca(OH)(2) (pH = 12.5) solutions.

CONCLUSION

Chlorhexidine exhibited both antioxidant and pro-oxidant properties under different conditions. These events are possibly involved in the killing of root canal and periodontal microorganisms when CHX and Ca(OH)(2) were used in combination or separately. Potential genotoxicity and tissue damage when extruded into the periradicular tissue and at higher concentrations should be considered during periodontal and endodontic practice.

Combined UGT1A1 and UGT1A7 variant alleles are associated with increased risk of Gilbert’s syndrome in Taiwanese adults

Gilbert's syndrome (GS) is caused by a reduction in the activity of hepatic bilirubin UDP-glucuronosyltransferase (UGT). This reduction is associated with UGT1A1*28 and UGT1A1*6 polymorphisms. Recent research also showed that carriage of UGT1A1*6 allele were significantly related with UGT1A7*3. Polymerase chain reaction-restriction fragment length polymorphism were utilized to determine UGT1A7 and UGT1A1 genes for 207 patients with GS and 207 gender/age-matched healthy controls. For the 207 healthy controls, linkage disequilibrium was observed between -57UGT1A7 and 622UGT1A7 loci (D' = 1.00 and r(2) = 1.00), -57UGT1A7 and 211UGT1A1 loci (D' = 0.72 and r(2) = 0.36), respectively. A dose-response effect for number of at-risk allele of UGT1A1 and risk for GS was noted (odds ratio (OR) = 8.19 for heterozygous UGT1A1*28 genotype; OR = 124.96 for homozygous UGT1A1*28 genotype; and p for trend <0.05). Patients with combined genotypes carrying UGT1A7 variant alleles and UGT1A1 variant alleles (including UGT1A1*28 and UGT1A1*6) are associated with increased risk of GS (OR = 13.96 for patients with combined genotype carrying at least one variant allele of UGT1A1 and UGT1A7). In conclusion, the -57UGT1A7 (T>G) is highly associated with UGT1A7*3 and moderately associated with 211UGT1A1 (G>A). Certain UGT1A1/UGT1A7 combined genotypes are risk factors of GS.

Chylothorax following extended thymectomy for myasthenia gravis

The effectiveness of extended thymectomy for the treatment of myasthenia gravis is well documented. Most of the postoperative complications have been related to respiratory distress or wound complication, but chylothorax following thymectomy has been reported as a rare complication. From January 1995 to December 2004, 217 patients underwent extended thymectomy for myasthenia gravis at Taipei Veterans General Hospital. Three cases (1.38%) developed chylothorax after operation. Injury to the unseen division of the mediastinal lymphatics and branches from the thoracic duct during extensive dissection of perithymic fat tissue, which is seldom performed in classical thymothymectomy procedures, may have been the main cause of this complication. Two of the cases received conservative treatment and recovered uneventfully. The other patient (0.46%) underwent ligation of the thoracic duct 3 months later, which also resulted in the complication being cured.

CONCLUSIONS

Post-thymectomy chylothorax is rare and seems to be related to extended thymectomy. Even a small invasive procedure such as VATS for extended thymectomy formyasthenia gravis could be complicated by chylothorax. We recommend that if chylothorax develops after thymectomy, conservative treatment is the treatment of choice; however, thoracic duct ligation is a useful method for treating long-term unhealed chylothorax.

Supradiaphragmatic Ectopic Liver: Delayed Traumatic Hepatic Hernia Mimics Pulmonary Tumor

We present a rare case of a 63-year-old woman, the oldest one in the literature, with supradiaphragmatic ectopic liver that mimics a pulmonary nodule. The chest roentgenogram and chest computer tomography showed a lobulated tumor nearby the diaphragm. Pathological examination of the resected tumor disclosed only remarkable fatty liver change. Ectopic liver should be kept in mind to differentiate for the pulmonary tumor nearby the diaphragm.

B-group vitamins, MTHFR C677T polymorphism and carotid intima-media thickness in clinically healthy subjects

OBJECTIVE

Plasma B-group vitamins and age may affect the carotid intima-media thickness (IMT) in subjects with different 677TT genotype of the methylenetetrahydrofolate reductase (MTHFR) gene.

DESIGN

A hospital-based cross-study.

SETTING

Genomic and Vascular Center, Changhua Christian Hospital, Changhua, Taiwan.

SUBJECTS

Five hundred and forty-one clinically healthy subjects.

INTERVENTION

Fasting plasma, homocysteine (Hcy), vitamin B(6), vitamin B(12), folate and B-mode carotid ultrasound.

RESULTS

MTHFR genotype, plasma concentrations of folate, vitamin B(6) and vitamin B(12) and age were significantly correlated to the plasma Hcy concentration. MTHFR 677TT carriers had higher concentrations of Hcy than did subjects with the CC and CT genotypes. Age, sex, body mass index and plasma Hcy were independent contributors to increase carotid IMT. However, with stratification by mean value of age and B-group vitamins concentrations, we found that at advanced age, lower plasma folate and vitamin B(12) were three risk factors involved in the enhancing effect of the MTHFR 677TT genotype on the increase of plasma Hcy and carotid IMT.

CONCLUSION

MTHFR 677TT-related carotid atherosclerosis was only identified in healthy elderly subjects with lower level of plasma folate and vitamin B(12).

SPONSORSHIP

Changhua Christian Hospital.

Non-traumatic colon perforation in children: a 10-year review

Colon perforation is an abdominal surgical emergency in the pediatric population, but is seldom reported when occurring from non-traumatic causes in children beyond the neonate. The goal of this study was to identify the clinical characteristics, management, and outcomes of non-traumatic colon perforation in children. Medical records for the 10-year period from September 1994 to September 2004 were reviewed for children beyond the neonate with non-traumatic colon perforation. Data gathered included age, gender, symptoms, duration of symptoms, physical findings, and length of postoperative hospital stay. Diagnostic information included laboratory data, radiographic imaging, and operative findings. Forty-four patients with non-traumatic colon perforation were recruited into this study. The mean age was 2.22 +/- 1.87 years; 91.4% of cases were younger than 5 years old. The most common presenting symptom was fever (97.7%); the most common sign was abdominal distention (93.1%). The mean duration of symptoms prior to admission was 6.19 days. Pneumoperitoneum was presented in 86.3% of patients by plain abdominal radiograph. Ascending and transverse colon were the most common perforation sites. Non-typhoid salmonella was the leading pathogen isolated, causing 20.4% of episodes. One case died due to Clostridium speticum infection. Non-traumatic colon perforation most commonly affects children younger than 5 years of age. It may be secondary to infection, especially non-typhoid salmonella. Plain abdominal radiograph can be an adjuvant tool for the high index of suspicion for colon perforation in children with abdominal distention and history of fever or diarrhea for more than 5 days.

Differential expression of glucocorticoid receptor in human breast tissues and related neoplasms

Glucocorticoid receptor (GR) is a steroid hormone receptor that has been shown to play important roles in mammary development and differentiation, and has been implicated in breast tumourigenesis, but its precise biological significance in mammary pathophysiology remains unclear. In order to generate a comprehensive expression profile for GR in normal versus neoplastic breast tissues, GR expression was investigated in situ in 400 human breast tissue samples, comprising normal tissue and a range of benign, pre-invasive, and invasive lesions, using immunohistochemical assays. The novel expression of GR in myoepithelium, not observed in luminal epithelium, not only demonstrates expression patterns exclusive to the alpha form of oestrogen receptor and progesterone receptor and suggests distinctive functions between GR and these two important steroid hormone receptors in the breast, but may also indicate unique physiological and perhaps pathological roles for the myoepithelium in mediating the effects of glucocorticoid hormones in the breast. The strong expression of GR in metaplastic carcinomas (94.4%) and malignant phyllodes tumours (92.3%) suggests a pathogenetic role for GR, and implies that targeting GR in these tumours may have potential therapeutic application. However, studies on the roles of GR in mammary carcinogenesis should be interpreted with great caution, based on the lack of GR expression in cancer cells in the great majority (98.2%) of non-metaplastic carcinomas, which has gone unnoticed in previous studies. This marked discrepancy warrants a re-examination of the biological roles of GR in the pathophysiology of breast malignancy. The lack of methylation in the promoter region of the GR gene in all 118 non-metaplastic carcinomas, as demonstrated by methylation-specific PCR and bisulphite DNA sequencing analysis, indicates that methylation is less likely to play a role in the reduction of GR expression in non-metaplastic carcinoma of the breast.

The suppressed proliferation and premature senescence by ganciclovir in p53-mutated human non-small-lung cancer cells acquiring herpes simplex virus-thymidine kinase cDNA

The concerted actions of molecular networks determine how cells undergo proliferation, death or aging. Here we show that the highly invasive, tumorigenic human non-small-cell-lung cancer (NSCLC) cells carrying mutated p53 alleles were transfected with herpes simplex virus-thymidine kinase (HSV-tk) cDNA and the selected clone was susceptible to exogenous ganciclovir (GCV). The work further indicated that, in the stable HSV-tk transfectants, GCV suppressed cell proliferation by inducing G(2)/M cell cycle arrest and premature senescence and the potency can be amplified through bystander effect. The growth suppression of the established tumor xenografts in nude mice can be successfully targeted by GCV. These data showed that the GCV-suppressed tumor cell proliferation can be coordinated by cell cycle arrest and cellular senescence in HSV-tk transfectant lacking wild-type p53.

Factors influencing the outcome of transsternal thymectomy for myasthenia gravis

BACKGROUND

Thymectomy is one of the current treatment strategies for patients with myasthenia gravis (MG); however, the selection criteria for surgery remain controversial.

METHODS

The demographic data and the surgical results of 168 patients with MG who underwent transsternal thymectomy from June 1986 to December 2000 were retrospectively reviewed. Follow-up information was obtained by review of the hospital records or telephone contact. The postoperative status of MG was assessed at the interval of 1, 3 and 6 months and then annually. The complete remission rate (CRR) between groups was compared.

RESULTS

A total of 168 patients, including 69 male patients and 99 female patients, with a mean age of 38.3 years (range 13-80 years), were analyzed. The symptom duration before operations was from 1 to 312 months with a mean of 33.8 months. Complete follow-up information was obtained on 154 patients (91.6%) with a mean follow-up duration of 98.9 months. Complete remission was achieved in 89 of 154 patients (57.8%) and marked clinical improvement in 47 patients (30.5%). Total improvement rate was 88.3%. Seventeen of 24 patients (70.8%) with ocular MG and 18 of 35 patients (51.4%) with thymoma had reached complete remission during the follow-up period. The CRR increased with each consecutive year and reached the plateau in the fourth postoperative year. There was no surgical mortality. The complication rate was 16.6%. Univariate analysis demonstrated that age <35 years old (P = 0.0001), symptom duration before operation <24 months (P = 0.01) and absence of preoperative steroid treatment (P = 0.04) were favorable prognostic factors. Multivariate Cox regression analysis revealed age <35 years old (odds ratio = 3.645, P = 0.001), symptom duration before operation <24 months (2.311, P = 0.041) were favorable prognostic factors for patients having transsternal thymectomy.

CONCLUSIONS

Transsternal thymectomy is feasible in the management of patients with MG at all stages with high improvement rate and low surgical morbidity. Those patients aged 35 years or less at operation, with symptoms developed <24 months before operation, may benefit more from thymectomy. MG patients with thymoma did as well as patients without thymoma, and 18 of 35 patients with thymoma had reached complete remission during the follow-up period. Thymectomy seems to be beneficial also for ocular MG.

Prolene hernia system compared with mesh plug technique: a prospective study of short- to mid-term outcomes in primary groin hernia repair

Two types of anterior tension-free hernioplasty, prolene hernia system (PHS) repair and mesh plug technique (MPT), were introduced to Taiwan in 2001. This study compared the short- to mid-term outcomes following primary groin hernia repair with PHS and MPT. From January 2001 to December 2003, 393 patients with 426 primary groin hernias were operated on by a single surgeon using MPT (n=192) and PHS (n=234). Baseline perioperative details and follow-up information were compared. Demographic characteristics of both groups were similar. The laterality, types of anesthesia, postoperative stay, postoperative wound pain scores, wound complications and days to return to activities of daily life were equally distributed between the two groups. However, the distribution of Gilbert types in the PHS group was shifted a little to the right compared with that of the MPT group. PHS repair had longer operative time (34+/-17 vs 25+/-9 minutes, p<0.01). No recurrence was noted in both groups during the follow-up from 5 to 41 months. Chronic non-disabling groin pains were noted in 2.8% (6/218) of patients in the PHS group and 8.9% (14/175) in the MPT group (p=0.01). Our results show that both PHS and MPT repairs can be performed with short operation time, minor wound pain and quick return to activities of daily life without short- to mid-term recurrences, but postoperatively the MPT group had higher incidence of chronic non-disabling groin pain. Although the MPT is less invasive, the additional protective patch in the preperitoneal space of the PHS may provide a further safeguard against recurrences, especially for those patients with attenuated inguinal floor. Long-term follow-up is needed.

Long-term results of major bile duct injury associated with laparoscopic cholecystectomy

BACKGROUND

Major bile duct injury (MBDI) is the most serious complication associated with laparoscopic cholecystectomy (LC). This study reports on long-term outcomes and clinical factors which predicted the outcome of 25 patients with LC-associated MBDI.

METHODS

Twenty-five consecutive patients receiving either primary (n = 11) or redo (n = 14) biliary reconstructive surgery at Cathay General Hospital for LC-associated MBDI were prospectively followed for 2 to 10 (mean, 4.5) years to assess their long-term outcomes. Twelve clinical factors relevant to their outcomes were analyzed.

RESULTS

There was no mortality. Although the 1-year postoperative results were successful in 23 patients (92%), the mid- to long-term outcomes were successful in only 17 patients (68%). Eight patients (32%) developed biliary strictures at an average of 3.3 years postoperatively and required subsequent reoperation or biliary stenting. Statistical comparison of 12 risk factors between the successful and unsuccessful groups revealed that two were significant, namely, repair performed by a nonreferral surgeon (p = 0.02) and repair at a stage with recent active inflammation (p = 0.04). A serum alkaline phosphatase level greater than 400 IU in the sixth postoperative month was highly correlated with long-term nonsuccess (p = 0.01).

CONCLUSIONS

Only 68% of patients with LC-associated MBDI who underwent reconstructive surgery at our institution had long-term success. A serum alkaline phosphatase level above 400 IU in the sixth postoperative month was predictive of nonsuccess. For better long-term results, repair should be performed by the referral surgeon at a stage without coexisting active inflammation.

Intravenous immunoglobulin in the preparation of thymectomy for myasthenia gravis

OBJECTIVES

A clinical trial including six patients was conducted to assess the effect of intravenous immunoglobulin (IVIg) in the preparation of thymectomy for patients with myasthenia gravis (MG).

MATERIAL AND METHODS

Six consecutive patients of type IIB MG treated with IVIg at a dose 0.4 g/kg daily for 5 days before thymectomy were enrolled in this study.

RESULTS

All patients responded positively to this treatment. Improvement began to occur 1-9 days after starting the injection (mean 3.33 days), and reached a maximum in 3-19 days (mean 6.50 days). Thymectomy was performed 9-13 days (mean 11.20 days) after starting the injection in five of the six patients with uneventful post-operative courses.

CONCLUSION

IVIg might be an alternative to plasmapheresis (PE) in the prethymectomy preparation of MG patients, and thymectomy should be performed within 2 weeks after IVIg treatment to minimize the perioperative complications. Controlled trial vs PE enrolling more patients is needed to assess the significance of the IVIg in the preparation of thymectomy for patients of MG.

Scavenging property of three cresol isomers against H2O2, hypochlorite, superoxide and hydroxyl radicals

Formocresol has long been used for pulpotomy of primary teeth and as an intracanal medicament. Little is known, however, about the pharmacological effect of tricresols. This study showed that three cresol isomers, o-cresol, m-cresol and p-cresol, are H2O2 scavengers with a 50% inhibitory concentration (IC50) of 502, 6.7 and 10.16 microM, respectively. o-, m- and p-cresol were also shown to be effective scavengers of superoxide radicals generated by xanthine/xanthine oxidase with an IC50 of 282, 153 and > 4000 microM, respectively, as analyzed by luminometer. o-, m- and p-cresol showed protective effects on the DNA breaks generated by H2O2/FeCl2 and FeCl3/ascorbate/H2O2 systems at concentrations ranging from 70 microM to 1.43 mM, o-, m- and p-cresol also showed differential protective effects against DNA breaks induced by 0.17% NaOCl with 100% inhibitory concentration (IC100) of about 10, 1 and 10 mM, respectively. In addition, reaction with 3% H2O2 and 0.17% NaOCl completely prevented NaOCl-induced DNA breaks. The results indicate that the three cresol isomers are effective ROS scavengers and may prevent ROS induced damage when used as pulpotomy agents or as intracanal medicaments. Owing to the difference in the position of the functional hydroxyl group in the three cresol isomers, m-cresol is the most effective ROS scavenger. Concomitant use of H2O2 for root canal irrigation may diminish both the tissue dissolving capacity of NaOCl and NaOCl-induced DNA damage.

Point mutation in the alpha helix of the HLA-C alpha2 domain generates a novel HLA-C allele,HLA-Cw*0106, in a Han Chinese individual in Taiwan

We report herein the identification of a new HLA-C allele using sequence-based typing (SBT). This novel allele, HLA-Cw*0106, was found in a Han Chinese individual from Taiwan. This individual was typed using SBT as having a class I HLA genotype of HLA-A*0206/0207, HLA-B*4601/5601, and HLA-Cw*0102/0106. This new allele differs from HLA-Cw*0102 in one of the nucleotides of the polymorphic exon 3 at codon 152 (GAG-->GTG; E152V). This residue is located in the alpha helix of the HLA-C alpha2 domain and may have the potential to affect the binding of HLA-C molecules with antigenic peptides and/or the interactions with the T cell receptor. This new allele was detected in a few individuals of Han Chinese in Taiwan, but has not yet been observed in the aboriginal populations in Taiwan.

Cooperative binding of gamma-glutamyl substrate to human glutathione synthetase

Human glutathione synthetase is responsible for catalyzing the final step in glutathione biosynthesis. It is a homodimer with a monomer subunit MW of 52 kDa. Kinetic analysis reveals a departure from linearity of the Lineweaver-Burk double reciprocal plot for the binding of gamma-glutamyl substrate, indicating cooperative binding. The measured apparent K(m) values for gamma-glutamyl-alpha-aminobutyrate (an analog of gamma-glutamyl-alpha-aminobutyrate) are 63 and 164 microM, respectively. Neither ATP (K(m) of 248 microM) nor glycine (K(m) of 452 microM) exhibits such cooperative binding behavior. Although ATP is proposed to play a key role in the sequential binding of gamma-glutamyl substrate to the enzyme, the cooperative binding of the gamma-glutamyl substrate is not affected by alterations of ATP concentration. Quantitative analysis of the kinetic results for gamma-glutamyl substrate binding gives a Hill coefficient (h) of 0.75, indicating negative cooperativity. Our studies, for the first time, show that human glutathione synthetase is an allosteric enzyme with cooperative binding for gamma-glutamyl substrate.