Development of a TaqMan minor groove binding probe-based quantitative reverse transcription polymerase chain reaction for the detection and quantification of Zika virus.

Zika virus (ZIKV) infection has emerged as a global health concern following epidemic outbreaks of severe neurological disorders reported in Pacific and Americas since 2016. Therefore, a rapid, sensitive and specific diagnostic test for ZIKV infection is critical for the appropriate patient management and the control of disease spread. A TaqMan minor groove binding (MGB) probe-based quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay was developed based on the conserved sequence regions of 463 ZIKV NS2B genes. The designed ZIKV qRT-PCR assay was evaluated for its detection limit, strain coverage and cross-reactivity. We further assessed the clinical applicability of qRT-PCR assay for ZIKV RNA detection using a total 18 simulated clinical specimens. The detection limit of the qRT-PCR assay was 11.276 ZIKV RNA copies at the 95% probability level (probit analysis, p<= 0.05). Both Asian and African ZIKV strains were detected by the qRT-PCR assay without cross-reacting with DENV-1, DENV-2, DENV-3, DENV-4, CHIKV, JEV, LGTV, GETV and SINV. The qRT-PCR assay demonstrated a perfect agreement (k = 1.000, P < 0.001) with the reference assay; the sensitivity and specificity of the qRT-PCR assay were 100% (95% CI= 79.6-100) and 100% (95% CI= 43.9-100) respectively. The qRT-PCR assay developed in this study is a useful diagnostic tool for the broad coverage detection and quantification of both the Asian and African ZIKV strains.

Cervical screening in foreign domestic workers in Singapore.

INTRODUCTION: Globally, cervical cancer is the fourth most common cancer in women, with about 85% occurring in low-middle income countries (LMIC) and an age-standardised incidence rate of more than 15 per 100,000. It is largely preventable through HPV vaccination and cervical cancer screening. In Singapore, 18% of the foreign domestic workforce hail from Indonesia, the Philippines, Myanmar, and India. However, there is no data on preinvasive cervical disease and cervical cancer in foreign domestic workers (FDWs) and the aim of this pilot programme is to determine the baseline screen positive rate of high-grade intraepithelial in this population. METHODS: A total of 322 FDWs were offered HPV screening through the Helping Our Helper (HOH) pilot programme. Data from this pilot programme were analysed and reported using simple descriptive statistics. RESULTS: Out of the 322 FDWs who registered for HPV screening, 68.6% participated. There was a 22.2% screen-positive rate; 10% of those who screened positive for high-risk HPV had histologically confirmed high-grade cervical intraepithelial neoplasia. This result is similar to other data on cervical cancer screening in Singaporeans. This pilot project screened less than 1% of the eligible FDWs in Singapore. DISCUSSION: The findings of this pilot programme suggest that there is public health value in providing cervical cancer screening to FDWs. Improving cervical cancer screening by increasing awareness and including routine cervical cancer screening as part of the employment medical examination should be studied.

Dedifferentiated endometrioid adenocarcinoma of the uterus: A case series and review of literature.

Introduction Dedifferentiated endometrioid adenocarcinoma (DEAC) was first described in 2007. However, it has only been recognised as a distinct subtype of endometrioid adenocarcinoma in the last 1-2 years. DEAC is a more aggressive histological subtype and carries a poorer prognosis. Patients with DEAC tend to present with advanced disease compared the other endometrioid adenocarcinomas. Methodology The study is a retrospective review of patients with DEAC diagnosed in two institutions in Singapore between January 2012 and October 2017. Results 7 patients were diagnosed with DEAC. The mean age was 56.4 years. All patients presented with either abnormal uterine bleeding or post menopausal bleeding. Out of the 7 patients, one was diagnosed with Stage 2 disease, 5 were diagnosed with Stage 3 disease and 1 was diagnosed with Stage 4 disease. One patient had neoadjuvant chemotherapy, followed by surgery, and completion chemotherapy post surgery. The other 6 patients (87.5%) underwent primary debulking surgery. Out of these 6 patients, 5 patients had adjuvant chemotherapy post surgery and one patient had both adjuvant chemotherapy and radiotherapy. Lymphovascular invasion was found in 71.4% of the cases. Conclusion DEAC is a more aggressive histological subtype of endometrioid adenocarcinomas. Better awareness of this condition can lead to proper diagnosis and treatment.

Mitochondrial uncoupling reveals a novel therapeutic opportunity for p53-defective cancers.

There are considerable challenges in directly targeting the mutant p53 protein, given the large heterogeneity of p53 mutations in the clinic. An alternative approach is to exploit the altered fitness of cells imposed by loss-of-wild-type p53. Here we identify niclosamide through a HTS screen for compounds selectively killing p53-deficient cells. Niclosamide impairs the growth of p53-deficient cells and of p53 mutant patient-derived ovarian xenografts. Metabolome profiling reveals that niclosamide induces mitochondrial uncoupling, which renders mutant p53 cells susceptible to mitochondrial-dependent apoptosis through preferential accumulation of arachidonic acid (AA), and represents a first-in-class inhibitor of p53 mutant tumors. Wild-type p53 evades the cytotoxicity by promoting the transcriptional induction of two key lipid oxygenation genes, ALOX5 and ALOX12B, which catalyzes the dioxygenation and breakdown of AA. Therefore, we propose a new paradigm for targeting cancers defective in the p53 pathway, by exploiting their vulnerability to niclosamide-induced mitochondrial uncoupling.

Uterine preservation in a young patient with adenosarcoma of the uterus - Case report and review of literature.

•A young lady with uterine sarcoma had a successful delivery 3 years after diagnosis.•Local recurrence occurred after 8 years.•Ultrasound and endometrial biopsy can be used in the follow-up of these patients.•Patients should be counselled on risk of late recurrence.

Dosimetric evaluation of magnetic resonance imaging-based intracavitary brachytherapy for cervical cancer.

The purpose of this study was to evaluate the dosimetric benefit of magnetic resonance imaging (MRI)-based dose adaptation in intracavitary brachytherapy (ICR) for cervical cancer. Dose-volume histograms were compared between matched conventional and optimized plans in 22 patients who were treated by MRI-based ICR. Doses to organs-at-risk (OAR) and dose covering 90% of high-risk clinical target volume (HR-CTV) were evaluated to compare OAR sparing and target coverage, respectively. The probability of RTOG rectal toxicity grade of ≥2 in the 22 patients was estimated based on the prediction model generated from previous three-dimensional CT-based ICR data. After optimization, doses to OAR showed a statistically significant decrease. The reduction percentage (reduced dose by optimization x 100/dose in the conventional plan) was higher in patients with HR-CTV >20 cc than in patients with HR-CTV >20 cc in the rectum. In patients with HR-CTV ≤ 20 cc, the mean probability of RTOG rectal toxicity grade ≥ 2 was 67.6% for the conventional plan and 47.8% for the optimized plan, based on the prediction model. In conclusion, dose adaptation by MRI-based ICR for cervical cancer resulted in significant dose reduction to the rectum, especially in patients with HR-CTV ≤ 20 cc.

Superiority of conventional intensity-modulated radiotherapy over helical tomotherapy in locally advanced non-small cell lung cancer. A comparative plan analysis.

PURPOSE: To compare helical tomotherapy (HT) and conventional intensity-modulated radiotherapy (IMRT) using a variety of dosimetric and radiobiologic indexes in patients with locally advanced non-small cell lung cancer (LA-NSCLC). PATIENTS AND METHODS: A total of 20 patients with LA-NSCLC were enrolled. IMRT plans with 4-6 coplanar beams and HT plans were generated for each patient. Dose distributions and dosimetric indexes for the tumors and critical structures were computed for both plans and compared. RESULTS: Both modalities created highly conformal plans. They did not differ in the volumes of lung exposed to > 20 Gy of radiation. The average mean lung dose, volume receiving ≥ 30 Gy, and volume receiving ≥ 10 Gy in HT planning were 18.3 Gy, 18.5%, and 57.1%, respectively, compared to 19.4 Gy, 25.4%, and 48.9%, respectively, with IMRT (p = 0.004, p < 0.001, and p < 0.001). The differences between HT and IMRT in lung volume receiving ≥ 10-20 Gy increased significantly as the planning target volume (PTV) increased. For 6 patients who had PTV greater than 700 cm(3), IMRT was superior to HT for 5 patients in terms of lung volume receiving ≥ 5-20 Gy. The integral dose to the entire thorax in HT plans was significantly higher than in IMRT plans. CONCLUSION: HT gave significantly better control of mean lung dose and volume receiving ≥ 30-40 Gy, whereas IMRT provided better control of the lung volume receiving ≥ 5-15 Gy and the integral dose to entire thorax. In most patients with PTV greater than 700 cm(3), IMRT was superior to HT in terms of lung volume receiving ≥ 5-20 Gy. It is therefore advised that caution should be exercised when planning LA-NSCLC using HT.

Case report of granular cell tumor of the vulva and review of current literature.

► We present four cases of benign granular cell tumours of the vulva managed between 1998 and 2001. ► We discuss the clinical and histopathological features of this condition. ► Treatment of this condition is primarily surgical.

Carcinoembryonic antigen screening: how far should we go?

INTRODUCTION: The role of carcinoembryonic antigen (CEA) in screening has been previously investigated and found to be inefficient because of its low sensitivity and specificity. Nevertheless, it is still used as a tumour marker in health screening packages, often for asymptomatic patients. We aimed to review all asymptomatic patients who were referred to our department for raised CEA, to determine if this was indeed associated with significant pathology, and to what extent the asymptomatic patients should be investigated. METHODS: All patients with no gastrointestinal symptoms, and whose only indication for endoscopy was a raised CEA level, were entered into the study group. All the investigations were retrospectively reviewed and any pathology was noted. RESULTS: There were 217 asymptomatic patients who presented for endoscopy and further evaluation due to raised CEA, from December 1998 to August 2004. After the initial investigations, a total of 20 primary and eight metastatic cancers were found. The malignancies detected included 11 colorectal cancers, two stomach cancers, five lung cancers, one periampullary carcinoma and one ovarian teratoma. There were two cases of metastasis in the lungs and six with liver metastasis. In the subsequent median follow-up period of 13 (range 6-97) months, an additional 16 (7.4 percent) primary cancers were detected. CONCLUSION: Asymptomatic average-risk patients who present with raised CEA should be investigated endoscopically and radiologically for commonly-associated cancers, and thereafter followed up for at least two years, as up to 7.4 percent present with a subsequent malignancy.

Robotic-assisted surgery for low rectal dissection: from better views to better outcome.

INTRODUCTION: The use of robotics in colorectal surgery is relatively new. The first few cases of colonic surgery using da Vinci Surgical System were reported in 2002. Since then, several centres had reported on their experience, with favourable outcomes. Our department started to embark on robotics in colorectal surgery in December 2007. The aim of our paper was to share our early experience with robotics in colorectal surgery and provide an update on the current status of robotics. METHODS: Preparations included formal training with the da Vinci Surgical System, certification of the surgeons, and obtaining Hospital Ethics committee approval. We used a hybrid technique of laparoscopic and robotic assistance in the resection of mid- to low-rectal cancer (total mesorectal excision). Laparoscopic approach was used to isolate the inferior mesenteric artery and for mobilisation of the left colon. The da Vinci robot was used in the dissection of the rectum down to the pelvic floor. We reviewed the outcomes of our early experience with emphasis on feasibility and safety. RESULTS: Over a period of three months, we performed eight cases of robotic-assisted colorectal surgery for cancer. The median age of the patients was 55 (range 42-80) years. The median operating time was 192.5 (range 145-250) minutes. There were no intraoperative or postoperative complications related to the use of robotics. The median length of hospital stay was five (range 4-30) days. CONCLUSION: Robotic-assisted laparoscopic colorectal surgery is a safe and feasible procedure.

Factors predicting the sentinel node metastases in T1 breast cancer tumor: an analysis of 1416 cases.

AIM: To determine the factors associated with the metastatic involvement of sentinel lymph node (SLN) biopsy in patients with early breast cancer. STUDY DESIGN: This was a retrospective study of patients with T1 invasive breast cancer who underwent SLN biopsy at Claudius Regaud Institute between January 2001 and September 2008. RESULTS: 1416 patients were recruited into this study. SLN metastases were detected in 368 patients (26%). Younger age, tumor size and location, histological type, nuclear grade, and lymphovascular invasion appear to be significant risk factors of SNL involvement. In multivariate analysis, tumor size, tumor location, histological type and lymphovascular invasion are significant factors. When the tumor size is >20 mm, the OR is 6.6 compared to a T1a tumor (3.145-14.175, p<0.001, confidence interval 95%). When the tumor is found in the inner quadrant, the risk of SLN involvement is reduced compared to external locations with an OR of 0.53 (0.409-0.709, p<0.001, confidence interval 95%). Non-ductal/lobular compared to infiltrative ductal cancer have a lower risk of SLN involvement with an OR of 0.423 (0.193-0.927, p<0.03, confidence interval 95%). Lymphovascular invasion increase the risk of positive SLN with an OR of 2.8 (1.9-4.1, p<0.001, confidence interval 95%). CONCLUSION: It appears reasonable to avoid axillary lymph node dissection in older patients with T1a tumors of good histopathological type and in the absence of lymphovascular invasion.

The asymmetric meiosis in pentaploid dogroses (Rosa sect. Caninae) is associated with a skewed distribution of rRNA gene families in the gametes.

In pentaploid dogroses, Rosa section Caninae (2n=5x=35), the pollen transmits one basic genome (x=7) derived from the seven segregating bivalents, whereas the egg transmits four basic genomes (4x=28) one set derived from the segregation of seven bivalents and three sets of univalent-forming chromosomes. Chromosomes from all five genomes carry 18-5.8-26S nuclear ribosomal DNA (rDNA) sites. This mode of sexual reproduction, known as permanent odd polyploidy, can potentially lead to the independent evolution of rDNA on bivalent- and univalent-forming chromosomes. To test this hypothesis, we analyzed rRNA gene families in pollen and somatic leaf tissue of R. canina, R. rubiginosa and R. dumalis. Six major rRNA gene families (alpha, beta, beta' gamma, delta and epsilon) were identified based on several highly polymorphic sites in the internal transcribed spacers (ITSs). At least two of the major rRNA gene families were found in each species indicating that rDNAs have not been homogenized across subgenomes. A comparison of ITS1 sequences from leaf and pollen showed differences: the shared beta rRNA gene family was more abundant among pollen clones compared to leaf clones and must constitute a major part of the rDNA loci on bivalent-forming chromosomes. The gamma and delta families were underrepresented in pollen genomes and are probably located predominantly (or solely) on the univalents. The results support the hypothesis that pentaploid dogroses inherited a bivalent-forming genome from a common proto-canina ancestor, a likely donor of the beta rDNA family. Allopolyploidy with distantly related species is likely to have driven evolution of Rosa section Caninae.

Identification of novel BRCA large genomic rearrangements in Singapore Asian breast and ovarian patients with cancer.

Large genomic rearrangements have been reported to account for about 10-15% of BRCA1 gene mutations. Approximately, 90 BRCA rearrangements have been described to date, all of which but one have been reported in Caucasian populations of predominantly Western European descent. Knowledge of BRCA genomic rearrangements in Asian populations is still largely unknown. In this study, we have investigated for the presence of BRCA rearrangements among Asian patients with early onset or familial history of breast or ovarian cancer. Using multiplex ligation-dependent probe amplification (MLPA), we have analyzed 100 Singapore patients who previously tested negative for deleterious BRCA mutations by the conventional polymerase chain reaction-based mutation detection methods. Three novel BRCA rearrangements were detected, two of which were characterized. The patients with the rearrangements, a BRCA1 exon 13 duplication, a BRCA1 exon 13-15 deletion and a BRCA2 exon 4-11 duplication, comprise 3% of those previously tested negative for BRCA mutations. Of the BRCA1 and BRCA2 pathogenic mutations identified in our studies on Asian high-risk breast and ovarian patients with cancer to date, these rearrangements constitute 2/19 and 1/2 of the BRCA1 and BRCA2 pathogenic mutations, respectively. Given the increasing number of rearrangements reported in recent years and their contribution to the BRCA mutation spectrum, the presence of BRCA large exon rearrangements in Asian populations should be investigated where clinical, diagnostic service is recommended.

Sonographic findings of placental lacunae and the prediction of adherent placenta in women with placenta previa totalis and prior Cesarean section.

OBJECTIVE: To investigate the value of transvaginal sonographic findings of intraplacental lacunae for predicting adherent placenta and clinical outcome in patients with placenta previa totalis and a history of Cesarean section. METHODS: Fifty-one patients with placenta previa totalis diagnosed by transvaginal sonography and with a history of Cesarean section who delivered at our hospital were included in the study. The sonographic findings of intraplacental lacunae were classified into one of four grades. Pathological analysis of the placenta was performed for all patients who delivered, and in cases of hysterectomy, examination of the uterus was also performed. The placental findings and obstetric complications, including massive transfusion, intensive care unit admission and Cesarean hysterectomy, were compared with the grade of lacuna. RESULTS: Lacunae were classified as Grade 1+ in 10 cases, Grade 2+ in 11 cases, Grade 3+ in five cases and as Grade 0 (i.e. lacunae were absent) in the remaining 25 cases. When lacunae of > or = Grade 1+ were considered, the sensitivity, specificity, positive predictive value and negative predictive value of diagnosing adherent placenta were 86.9%, 78.6%, 76.9% and 88.0%, respectively. When lacunae of > or = Grade 2+ were considered, the sensitivity, specificity, positive predictive value and negative predictive value of diagnosing placenta increta or percreta were 100%, 97.2%, 93.8% and 100%, respectively. Hysterectomy was performed in 18 cases, among whom two cases showed Grade 1+ lacunae, 11 cases showed Grade 2+ lacunae, and five cases showed Grade 3+ lacunae. No hysterectomy was performed in any case in which lacunae were absent. Compared to those without lacunae, the number of massive transfusions and intensive care unit admissions and cases of disseminated intravascular coagulopathy and Cesarean hysterectomy were significantly greater in those with lacunae (P < 0.0001). CONCLUSION: Transvaginal sonographic findings of intraplacental lacunae in patients with placenta previa totalis and a history of Cesarean section are useful in the prediction of adherent placenta and may have a role in the prediction of clinical outcome.

PPH03 stapled hemorrhoidopexy: our experience.

BACKGROUND: Stapled hemorrhoidopexy is an established treatment for hemorrhoidal disease. We evaluated our experience with stapled hemorrhoidopexy using the new Procedure for Prolapse and Hemorrhoids (PPH03) Proximate HCS hemorrhoidal circular stapler (Ethicon Endo-Surgery). METHODS: We retrospectively reviewed clinical data for 238 patients who had undergone stapled hemorrhoidopexy in our department over a 2-month period. Patients were followed-up for a median of 3.5 weeks (range, 1-11 weeks) and were analyzed for complications and resolution of symptoms. RESULTS: The hemorrhoids treated were third- and fourth-degree, as well as second degree (after failure of other therapies). Mean duration of surgery was 12.7 minutes (range, 5-20 minutes) and the majority of patients was treated with an ambulatory procedure. Most patients were discharged within 6 hours after surgery. On follow-up, 3.7% of patients had minor complaints after surgery. Technically, the new PPH03 stapler device has a quickclose knob, which allows rapid opening and closing. The closed staple height of 0.75 mm increases staple line compression on tissue and key blood vessels, hence minimizing bleeding. Prior to this, stapled hemorrhoidopexy was done using the PPH01 device. CONCLUSIONS: Stapled hemorrhoidopexy using the new PPH03 stapler is a safe, short and effective procedure in the management of hemorrhoids. It can be done in the ambulatory setting and patients have few postoperative complications.

Physical phantom of typical Korean male for radiation protection purpose.

Dose distribution within a human body can be measured using physical anthropomorphic phantoms. In an effort to establish reference Korean physical model, the first Korean physical phantom of average Korean adult male was constructed using computed tomography (CT) images of a healthy volunteer. The body dimension of the subject was close to that of average Korean male. The source images were obtained using fusion positron emission tomography machine at Radiation Health Research Institute in Korea, and ported into rapid prototyping process. The physical phantom was composed of three tissue-equivalent materials: epoxy resin, urethane foam and polyurethane representing bone, lungs and soft tissues, respectively. The densities of the tissue-equivalent materials were close to those recommended by the International Commission on Radiation Units and measurements. To facilitate dose mapping, the phantom was sliced into 2 cm sections. Hole grids for thermoluminescence (TL) dosemeter chips were drilled. To verify the appropriateness of the physical phantom, organ doses of selected organs were measured for reference photon beam, and compared with those computed by tomographic model constructed from the same CT images. Absorbed doses converted from TL relative response showed good agreement within 7% with those calculated.

In vivo organ mass of Korean adults obtained from whole-body magnetic resonance data.

In vivo organ mass of the Korean adult, male and female were presented for the purpose of radiation protection. A total of 121 healthy volunteers (66 males and 55 females), whose body dimensions were close to that of average Korean adults, were recruited for this study. Whole-body magnetic resonance (MR) images were obtained, and contours of 15 organs (brain, eye, gall bladder, heart, kidney, liver, lung, pancreas, stomach, spleen, testes, thymus, thyroid, urinary bladder and uterus) and 9 bones (femur, tibia + fibula, humerus, radius + ulna, pelvis, cervical spine, thoracic and lumber spine, skull and clavicle) were segmented for organ volume rendering by anatomists using commercial software. Organ and bone masses were calculated by multiplying the Asian reference densities of the corresponding organs and bones by the measured volumes. The resulting organ and bone masses were compared with those of the International Commission of Radiological Protection (ICRP) and the Asian reference data. Significantly large standard deviation was shown in the moving organs of the respiratory and circulatory systems and in the alimentary and urogenital organs that are variable in volume in a single person. Gall bladder and pancreas showed unique Korean organ masses compared with those of ICRP and the Asian reference adults. Different from anatomical data based on autopsy, the in vivo volume and mass in this study can more exactly describe the organ volume of a living human subject for radiation protection. A larger sample size would be required for obtaining statistically more reliable results. It is also needed to establish the reference organ mass of younger age groups for which it is difficult to recruit volunteers and to immobilise the subjects for long-time MR scanning. At present, the data from this study will contribute to the establishment of a Korean reference database.

Outcomes of twin-twin transfusion syndrome managed by a specialised twin clinic.

INTRODUCTION: To determine the perinatal outcomes of monochorionic (MC) pregnancies complicated by the twin-twin transfusion syndrome (TTTS) that were managed in a specialised twin clinic at the KK Women's and Children's Hospital. METHODS: This was a 21-month retrospective study carried out from January 2002 to September 2003. MC pregnancies were followed up every two to three weeks with regular ultrasonographical and Doppler studies from the time monochorionicity was diagnosed. Standard criteria used for the diagnosis of TTTS are the presence of oligohydramnios/polyhydramnios sequence on ultrasonography. The severity of TTTS was staged according to Quintero's system. RESULTS: There were 77 sets of MC pregnancies in our database. 11 sets were diagnosed with TTTS, hence the incidence was 14.3 percent. The median gestation at diagnosis of TTTS was 17.4 (16.4 to 26) weeks. At first presentation, five were stage I, two were stage II, three were stage III and one was stage IV. Three pregnancies were terminated in the second trimester and one was lost to follow-up. Of the other seven, two were treated expectantly or delivered, four with amnioreduction/ septostomy and one with cord occlusion. The median gestation at delivery is 30.8 (26.7 to 36.9) weeks. Four (57 percent) were delivered before 32 weeks and these same four pairs required neonatal intensive care. The overall perinatal survival was 78 percent (11/14) and the median diagnosis to delivery interval was 10.7 (3.1 to 17.5) weeks. CONCLUSION: TTTS occurs in a significant proportion of MC pregnancies. The perinatal survival outcome of this group of patients managed in this clinic is comparable to that of other good centres.

Ascorbate attenuates trimethyltin-induced oxidative burden and neuronal degeneration in the rat hippocampus by maintaining glutathione homeostasis.

The specific role of endogenous glutathione in response to neuronal degeneration induced by trimethyltin (TMT) in the hippocampus was examined in rats. A single injection of TMT (8 mg/kg, i.p.) produced a rapid increase in the formation of hydroxyl radical and in the levels of malondialdehyde (MDA) and protein carbonyl. TMT-induced seizure activity significantly increased after this initial oxidative stress, and remained elevated for up to 2 weeks post-TMT. Although a significant loss of hippocampal Cornus Ammonis CA1, CA3 and CA4 neurons was observed at 3 weeks post-TMT, the elevation in the level of hydroxyl radicals, MDA, and protein carbonyl had returned to near-control levels at that time. In contrast, the ratio of reduced to oxidized glutathione remained significantly decreased at 3 weeks post-TMT, and the glutathione-like immunoreactivity of the pyramidal neurons was decreased. However glutathione-positive glia-like cells proliferated mainly in the CA1, CA3, and CA4 sectors and were intensely immunoreactive. Double labeling demonstrated the co-localization of glutathione-immunoreactive glia-like cells and reactive astrocytes, as indicated by immunostaining for glial fibrillary acidic protein. This suggests that astroglial cells were mobilized to synthesize glutathione in response to the TMT insult. The TMT-induced changes in glutathione-like immunoreactivity appear to be concurrent with changes in the expression levels of glutathione peroxidase and glutathione reductase. Ascorbate treatment significantly attenuated TMT-induced seizures, as well as the initial oxidative stress, impaired glutathione homeostasis, and neuronal degeneration in a dose-dependent manner. These results suggest that ascorbate is an effective neuroprotectant against TMT. The initial oxidative burden induced by TMT may be a causal factor in the generation of seizures, prolonged disturbance of endogenous glutathione homeostasis, and consequent neuronal degeneration.