Quantitative Proteomics Using Isobaric Labeling: A Practical Guide / 基因组蛋白质组与生物信息学报·英文版

In the past decade, relative proteomic quantification using isobaric labeling technology has developed into a key tool for comparing the expression of proteins in biological samples. Although its multiplexing capacity and flexibility make this a valuable technology for addressing various biological questions, its quantitative accuracy and precision still pose significant challenges to the reliability of its quantification results. Here, we give a detailed overview of the different kinds of isobaric mass tags and the advantages and disadvantages of the isobaric labeling method. We also discuss which precautions should be taken at each step of the isobaric labeling workflow, to obtain reliable quantification results in large-scale quantitative proteomics experiments. In the last section, we discuss the broad applications of the isobaric labeling technology in biological and clinical studies, with an emphasis on thermal proteome profiling and proteogenomics.

Effects and Mechanism of Qiwei Qinggan Powder on Hepatic Fibrosis Based on Proteomics / 中国药房

OBJECTIVE：To investigate the anti- hepatic fibrosis （HF）effects of Qiwei qinggan powder and explore its possible mechanism. METHODS ：Male Wistar rats were randomly divided into blank group ，HF model group ，Qiwei qinggan powder low-dose，medium-dose and high-dose groups [ 135，270，405 mg/（kg·d），by total amount of crude drugs] ，with 12 rats in each group. Except for blank group ，other groups were given 50％ CCl4-peanut oil solution intragastrically （2 mL/kg，twice a week ，for consecutive 8 weeks） to induce HF model. At same time ， blank group and model group were given constant volume of 0.5％ CMC-Na solution intragastrically ；administration groups were given relevant medicine intragastrically ，once a day ，for consecutive 8 weeks. General situation of rats were observedand liver morphology was observed after last administration and hepatic indexes were detected. The contents of liverfunction indexes （ALT，AST，ALP，HYP）in serum and the expression of α-SMA in hepatic tissue were determined ， and HE and Masson staining were performed to observe the histopathology. Using the difference multiple of expression quantity as the index ，TMT technology was used to screen the differentially expressed protein in medicine group （combining the liver tissue samples of Qiwei qinggan powder groups ）and HF model group. Uniprot-GOA database and KAAS ，KEGG mapper online tools were used to analyze GO and KEGG pathway enrichment. RESULTS ：The rats in the blank group were in good health ；the liver was bright red and smooth ，the liver lobules were intact ，no degeneration and necrosis ，inflammatory cell infiltration or fibrous tissue proliferation was found. Compared with blank group ，the rats in HF model group had poor diet ，depressed spirit ，disordered and lusterless fur ；the liver was dark red or yellow with rough surface ，hard texture ，inflammatory cell infiltration ，fiber tissue destruction ，bridge connection and so on ；the hepatic index ，the contents of liver function indexes and the expression of α-SMA were increased significantly （P＜0.05）. Compared with HF model group ，above symptoms of rats were improved to different extent in different dose groups of Qiwei qinggan powder ；hepatic index in Qiwei qinggan powder low-dose group ，the content of ALP in high-dose group ，the contents of ALT，AST and HYP and the expression of α-SMA in different dose groups were decreased significantly （P＜0.05）. A total of 42 differentially expressed proteins related to HF were screened ，of which 15 were up-regulated and 27 were down-regulated in expression，including fatty acid binding protein 4（FABP4），cholesterol 7α-hydroxylase（CYP7A1）. The results of enrichment analysis showed that the differentially expressed proteins were mainly enriched in extracellular space ，blood particles and other cell parts，involving the molecular functions of oxidoreductase activity and fatty acid binding ，the biological processes of the regulation of heterotypic cell adhesion ，protein activation cascade ，as well as retinol metabolism ，arachidonic acid metabolism ，PPAR and other signal pathway. CONCLUSIONS ：Qiwei qinggan powder can reduce the hepatic index ，ALT，AST，ALP and HYP contents in serum ，down-regulate the expression of α-SMA，improve the degree of inflammation and fibrosis of liver tissue ，and have a certain protective effect on rats. The anti-HF mechanism of it involves multiple targets and signal pathways ，such as FABP 4， CYP7A1 and PPAR.

Comparative Reliability Of Tinetti Mobility Test And Tug Tests In People With Neurological Disorders

Background: In recent years, many tests have been developed to evaluate the mobility and functional capacity of people with neurological disorders (Hemiplegia, MS). The purpose of this study was to test the reliability and additionally to determine the measurement error of TMT and TUG in adults with neurological disorders (hemiplegia, MS). Methods: In the study of tests 20 adults (11 with multiple sclerosis and 9 with hemiplegia) who were retrospectively registered participated. The average age of adults was 38.7 ± 13.9 years old and their average body mass was 65.1 ± 13.1kg. The Greek version of the tests and a Nikon 5300 digital camera for video recording were used for data collection. ICC was calculated by means of a two-way ANOVA model. Results: The results showed that there were no statistically significant differences between the two independent evaluators and that the TMT (ICC > 0,936 ) and TUG (ICC> 0,996) had strong reliability. Conclusions: Overall, the results of the present investigation provided considerable evidence suggesting that the tests TMT and TUG are reliable and can be used to evaluate kinetic and balance disorders. Therefore, it was concluded that the tests should be applied to reliably estimate the mobility and functional ability of adults with neurological disorders.

Transcriptome and proteome analyses of resistant preharvest peanut seed coat in response to Aspergillus flavus infection

BACKGROUND: The infection of peanut (Arachis hypogaea L.) seed coat by the pathogenic fungus Aspergillus flavus has highly negative economic and health impacts. However, the molecular mechanism underlying such defense response remains poorly understood. This study aims to address this issue by profiling the transcriptomic and proteomic changes that occur during the infection of the resistant peanut cultivar J11 by A. flavus. RESULTS: Transcriptomic study led to the detection of 13,539 genes, among which 663 exhibited differential expression. Further functional analysis found the differentially expressed genes to encode a wide range of pathogenesis- and/or defense-related proteins such as transcription factors, pathogenesis-related proteins, and chitinases. Changes in the expression patterns of these genes might contribute to peanut resistance to A. flavus. On the other hand, the proteomic profiling showed that 314 of the 1382 detected protein candidates were aberrantly expressed as a result of A. flavus invasion. However, the correlation between the transcriptomic and proteomic data was poor. We further demonstrated by in vitro fungistasis tests that hevamine-A, which was enriched at both transcript and protein levels, could directly inhibit the growth of A. flavus. Conclusions: The results demonstrate the power of complementary transcriptomic and proteomic analyses in the study of pathogen defense and resistance in plants and the chitinase could play an important role in the defense response of peanut to A. flavus. The current study also constitutes the first step toward building an integrated omics data platform for the development of Aspergillus-resistant peanut cultivars

TMT proteomics and bioinformatics to analyze protein differences in different Hup A content of thallus of Huperzia serrata / 中草药

Objective: To analyze the differences in protein of thallus of Huperzia serrata (in vitro cultures, strains A, B, and C, respectively) with different Hup A content, and to explore related enzymes that may be synthesized with Hup A accumulation. Methods: Quantitative proteomics was performed in vitro cultures of Huperzia serrata with different Hup A content using quantitative proteomics tandem mass tag (TMT) techniques, followed by differential protein analysis: GO, KEGG and other biological information analysis. Results: Strain B hadthe lowest Hup A content and strain C had the highest Hup A content, which was twice than that of B. There were 78 differential proteins between the strain B and C. Analysis of differential protein GO enrichment showed that MF accounted for 28.75%; Analysis of differential protein expression showed that three strains shared two differential proteins (P93541, Q8RXU4) in the alkaloid metabolic pathway starting from amino acids. P93541 protein was down-regulated in the low-yield strain B and up-regulated in the relatively high-yield strains A and C. The Q8RXU4 protein was up-regulated in the low-yield strain B and down-regulated in the relatively high-yield strains A and C. Conclusion: This study found that the difference in Hup A content was positively correlated with the protein expression. Two enzymes P93541 and Q8RXU4 that may be related to Hup A accumulation were analyzed, providing a basis for bioinformatics analysis of Hup A biosynthesis.

Quantitative proteomics and differential signal enrichment in nasopharyngeal carcinoma cells with or without gene knockout / 南方医科大学学报

OBJECTIVE@#To analyze the effects of alterations in the expressions of methyltransferase on protein expression profiles in human nasopharyngeal carcinoma (NPC) cells and enrich the differential signaling pathways.@*METHODS@#The total protein was extracted from -knockout cell line CNE1 and the wild-type cell line CNE1, and the differentially expressed proteins were screened by tandem mass tag (TMT) labeled protein quantification technique and tandem mass spectrometry. GO analysis was used to annotate and enrich the differentially expressed proteins, and the KEGG database was used to enrich and analyze the pathways of the differential proteins.@*RESULTS@#With a fold change (FC)≥1.2 and < 0.05 as the screening standard, 2049 differentially expressed proteins were identified in CNE1 cells, among which 904 were up-regulated and 1145 were down-regulated. GO functional annotation results indicated that knockout caused characteristic changes in multiple biological processes (cell processes and regulation, cell movement, metabolic processes, and biosynthesis of cellular components), molecular functions (catalytic activity and molecular binding, transcription factor activity), and cellular components (cell membrane, organelle, macromolecular complex). KEGG analysis showed that the differentially expressed proteins were involved in an array of signaling pathways closely related to tumors, including MAPK, PI3K-Akt, Ras, Rap1, mTOR, Hippo, HIF-1, Wnt, AMPK, FoxO, ErbB, P53 and JAK-STAT.@*CONCLUSIONS@# knockout significantly changes the protein expression characteristics of NPC cells and affects a number of signal pathways closely related to tumors. The results provide evidence for investigation of the pathogenesis and therapeutic target screening of NPC.

Treadmill stress tests should not be part of “routine health check package”

A treadmill ECG stress test (TMT) often forms part of the popular health check packages recommended for people who are asymptomatic on the premise that it can detect disease at an early stage and treatment be prescribed to prevent or reduce future morbidity and mortality. Such a recommendation does not take into account the properties of this procedure as a diagnostic test. It has an average sensitivity and specificity of 68% and 77%, respectively. However, these figures depend on the probability of coronary artery disease (CAD) in the test subject. In asymptomatic persons with few or no risk factors, the likelihood of a false positive is high and will result in psychological stress and/or expensive and possibly invasive test. Recommendation for a TMT should be made by a physician after evaluating the subject to have at least an intermediate risk of having CAD.

A novel approach for the prediction of treadmill test in cardiology using data mining algorithms implemented as a mobile application

Objective To develop a mobile app called “TMT Predict” to predict the results of Treadmill Test (TMT), using data mining techniques applied to a clinical dataset using minimal clinical attributes. To prospectively test the results of the app in realtime to TMT and correlate with coronary angiogram results. Methods In this study, instead of statistics, data mining approach has been utilized for the prediction of the results of TMT by analyzing the clinical records of 1000 cardiac patients. This research employed the Decision Tree algorithm, a new modified version of K-Nearest Neighbor (KNN) algorithm, K-Sorting and Searching (KSS). Furthermore, curve fitting mathematical technique was used to improve the Accuracy. The system used six clinical attributes such as age, gender, body mass index (BMI), dyslipidemia, diabetes mellitus and systemic hypertension. An Android app called “TMT Predict” was developed, wherein all three inputs were combined and analyzed. The final result is based on the dominating values of the three results. The app was further tested prospectively in 300 patients to predict the results of TMT and correlate with Coronary angiography. Results The accuracy of predicting the result of a TMT using data mining algorithms, Decision Tree and K-Sorting & Searching (KSS) were 73% and 78%, respectively. The mathematical method curve fitting predicted with 82% accuracy. The accuracy of the mobile app “TMT Predict”, improved to 84%. Age-wise analysis of the results show that the accuracy of the app dips when the age is more than 60 years indicating that there may be other factors like retirement stress that may have to be included. This gives scope for future research also. In the prospective study, the positive and negative predictive values of the app for the results of TMT and coronary angiogram were found to be 40% and 83% for TMT and 52% and 80% for coronary angiogram. The negative predictive value of the app was high, indicating that it is a good screening tool to rule out coronary artery heart disease (CAHD). Conclusion “TMT Predict” is a simple user-friendly android app, which uses six simple clinical attributes to predict the results of TMT. The app has a high negative predictive value indicating that it is a useful tool to rule out CAHD. The “TMT Predict” could be a future digital replacement for the manual TMT as an initial screening tool to rule out CAHD.

Upregulation of CD47 in Regulatory T Cells in Atopic Dermatitis

PURPOSE: Regulatory T (Treg) cells are key modulators in the immune system. Recent studies have shown that atopic dermatitis (AD) patients have higher numbers of Treg cells; however, little is known about the specific phenotype and function of Treg cells in AD. MATERIALS AND METHODS: To identify differentially expressed proteins in peripheral induced Treg cells in AD and naturally derived Treg cells in normal controls, CD4?CD25? Treg cells were isolated from thymus tissue of normal mice and the spleens of AD mice. Membrane proteins were extracted, and quantitative proteomics labeling with Tandem Mass Tags (TMT) was performed, followed by one-dimensional liquid chromatography/tandem mass spectrometry analysis. RESULTS: Using TMT labeling, we identified 510 proteins, including 63 membrane proteins and 16 plasma membrane proteins. CD47 was one of the upregulated proteins in Treg cells in AD spleens. Although CD47 was expressed in all CD4? and CD8? T cells, a significantly higher expression of CD47 was observed in the Treg cells of AD mice and AD patients than in those of normal mice and healthy controls. Furthermore, Treg cells from the spleen showed a significantly higher expression of CD47 than those from the thymus. CONCLUSION: We found that CD47 is highly expressed in the Treg cells of AD mice, particularly in the spleen. Based on our results, we propose that CD47(high) Treg cells are likely induced Treg cells and that upregulated CD47 in the Treg cells of AD patients may play a role in the increased population of Treg cells in AD.

Upregulation of CD47 in Regulatory T Cells in Atopic Dermatitis

PURPOSE: Regulatory T (Treg) cells are key modulators in the immune system. Recent studies have shown that atopic dermatitis (AD) patients have higher numbers of Treg cells; however, little is known about the specific phenotype and function of Treg cells in AD. MATERIALS AND METHODS: To identify differentially expressed proteins in peripheral induced Treg cells in AD and naturally derived Treg cells in normal controls, CD4?CD25? Treg cells were isolated from thymus tissue of normal mice and the spleens of AD mice. Membrane proteins were extracted, and quantitative proteomics labeling with Tandem Mass Tags (TMT) was performed, followed by one-dimensional liquid chromatography/tandem mass spectrometry analysis. RESULTS: Using TMT labeling, we identified 510 proteins, including 63 membrane proteins and 16 plasma membrane proteins. CD47 was one of the upregulated proteins in Treg cells in AD spleens. Although CD47 was expressed in all CD4? and CD8? T cells, a significantly higher expression of CD47 was observed in the Treg cells of AD mice and AD patients than in those of normal mice and healthy controls. Furthermore, Treg cells from the spleen showed a significantly higher expression of CD47 than those from the thymus. CONCLUSION: We found that CD47 is highly expressed in the Treg cells of AD mice, particularly in the spleen. Based on our results, we propose that CD47(high) Treg cells are likely induced Treg cells and that upregulated CD47 in the Treg cells of AD patients may play a role in the increased population of Treg cells in AD.

Early detection of coronary artery disease in asymptomatic type 2 diabetes mellitus patients.

Type II Diabetes Mellitus (DM) is a major risk factor for Coronary Artery Disease (CAD). Patients remain mostly asymptomatic and thus diagnosed at an advance stage of the disease. Our aim of study was to detect the CAD at an early stage in asymptomatic diabetic patients. Methods: 136 asymptomatic type II diabetes mellitus patients were enrolled prospectively for treadmill test (TMT) and subsequent coronary angiography (CAG) was performed on 96 (70.87%) TMT positive patients. Diabetic status, clinical parameters including risk factors, TMT and angiographic findings were analyzed. Results: The patients were divided into two groups, high rich group A (risk factor >2) and low risk group B (risk factor >1). 34 patients of group A (36.95%) were CAD positive out of 92 patients of high risk group and 4 patients group B (9.09%) out of 44 patients of low rich group. Duration of diabetes mellitus and multiple risk factors were correlated with coronary artery disease (CAD) as well as multiple coronary artery involvement. Conclusions: A routine TMT of all long standing asymptomatic type 2 diabetic patients (>10 years) with family history of CAD and subsequent CAG should be done on all TMT positive patients for early detection of CAD to take early appropriate revascularization measure.

Relationship between the increase in cerebral blood flow and the attentional function during exercise / 体力科学

Although there are a number of reported cases of increased cerebral blood flow during exercise, there are no reports on the relation between changes of blood flow during exercise and attentional function. The purpose of this study is to clarify the relation between changes of blood flow during exercise with AT intensity and attentional function, using near-infrared spectral analysis. The subjects were 10 healthy males. The research protocol was to conduct steady load exercise. We randomly conducted two invention trials: 1) an exercise/task trial in which a trail making test (TMT) was performed as an attentional assignment during steady load exercise, and 2) a rest/task trial in which TMT was performed during rest as a control. As a result, we observed the following: increase of oxy-Hb in the prefrontal cortex during AT exercise, the significant shortening of TMT during exercise from 69.1±10.2 seconds to63.2±7.2seconds, and, with further control, that the more oxy-Hb rises, the more TMT time is shortened. From these results, it is suggested that 10 minutes of exercise would improve attentional function, and furthermore, there is a possibility that increased cerebral blood flow may be involved with the improvement of attentional function.

Radiological Analysis of Osteoarthritis of the Second Metatarsophlangeal and Tarsometatarsal Joint / 대한족부족관절학회지

PURPOSE: The aim of this study was to investigate the radiological characteristics of the osteoarthritis of the second metatarsophalangeal (MTP) and tarsometatarsal (TMT) joint. MATERIALS AND METHODS: Between January 2002 and August 2010, 27 patients (33 feet) who had second metatarsal osteoarthritis (OA) were reviewed retrospectively. Group 1 was 14 patients (17 feet) with second MTP joint OA. Group 2 was 13 patients (16 feet) with second TMT joint OA. Group 3 was 24 patients (25 feet) had hallux valgus without second metatarsal (MT) OA as control. Weight bearing foot anteroposterior (AP) and lateral view were checked, and measured hallux valgus angle, metatarsus adductus angle (MAA), second MT functional length, first and second MT length by Hardy & Clapham method on AP view, angle of second MT with horizontal plane, calcaneal pitch, talo-first MT on lateral view. RESULTS: On weight bearing foot AP view, second MT functional length of group 1, 2, 3 was 2.4 mm, -0.1 mm, 0.7 mm and MAA of group 1, 2, 3 was 17.7degrees, 17.7degrees, 14.5degrees. Second MT functional length of group 1 was longer than control group and it was statistically significant. MAA was significant different between group 1-3 and group 2-3. Angle of second MT with horizontal plane of group 2 was smaller than control group and it was statistically significant. Other radiographic parameters have no statistical significance. CONCLUSION: Group 1 has long functional length of second MT and group 2 has small angle of second MT with horizontal plane.

Neuroprotective Effect of Lucium chinense Fruit on Trimethyltin-Induced Learning and Memory Deficits in the Rats

In order to the neuroprotective effect of Lycium chinense fruit (LCF), the present study examined the effects of Lycium chinense fruit on learning and memory in Morris water maze task and the choline acetyltransferase (ChAT) and cyclic adenosine monophosphate (cAMP) of rats with trimethyltin (TMT)-induced neuronal and cognitive impairments. The rats were randomly divided into the following groups: naive rat (Normal), TMT injection+saline administered rat (control) and TMT injection+LCF administered rat (LCF). Rats were administered with saline or LCF (100 mg/kg, p.o.) daily for 2 weeks, followed by their training to the tasks. In the water maze test, the animals were trained to find a platform in a fixed position during 6d and then received 60s probe trial on the 7th day following removal of platform from the pool. Rats with TMT injection showed impaired learning and memory of the tasks and treatment with LCF (p<0.01) produced a significant improvement in escape latency to find the platform in the Morris water maze at the 2nd day. Consistent with behavioral data, treatment with LCF also slightly reduced the loss of ChAT and cAMP in the hippocampus compared to the control group. These results demonstrated that LCF has a protective effect against TMT-induced neuronal and cognitive impairments. The present study suggests that LCF might be useful in the treatment of TMT-induced learning and memory deficit.

A Case of Acute Organotin Poisoning / 대한산업의학회지

BACKGROUND: Although organotin compounds are widely used as PVC stabilizers, catalysts and biocides, their effects on humans are not well known. However, their acute intoxication is known to cause neurotoxicity in the central nervous system, renal toxicity, and hepatotoxicity. As there has been no previously published case of organotin intoxication in Korea, we report here the first Korean case of acute exposure to organotin. CASE REPORT: A 43-year-old male with disorientation and behavioral change was admitted to a hospital. He had been working as a tank cleaner for several different companies in the previous 8 years and a week before admission, he had cleaned a tank containing dimethyltin (DMT) for 4 days. A day after finishing the job, he suffered decreased memory, behavioral change and progressive mental deterioration when he arrived at the emergency room. The result of spinal tapping was negative but on the 4th day of admission he deteriorated into a state of coma along with metabolic acidosis and severe hypokalemia. High levels of DMT and trimethyltin (TMT) were detected in a highly sensitive urine analysis. After conservative treatment and chelation therapy, the patient showed some clinical improvement but the neurological defects persisted. CONCLUSION: The patient appeared to have been intoxicated from the acute exposure to a high level of organotin while cleaning the tank.

Effect of Midazolam Premedication on Postanesthetic Recovery and Postanesthetic Recovery Room Discharge Time for Outpatient Surgery / 대한마취과학회지

BACKGROUND: Midazolam is often used as an anxiolytic premedication before surgery. But preoperatively administered midazolam may contribute to postopertive sedation and delayed recovery from general anesthesia. This study was undertaken to evaluate the effect of midazolam premedication on postoperative recovery and discharge-readiness after brief outpatient surgery. METHODS: Sixty healthy ASA physical status I women scheduled for outpatient diagnostic laparoscopic surgery were considered for the study. They were randomly allocated to one of two groups. Group one received normal saline (N/S) 5 ml intravenously (IV), while group two received IV midazolam 0.04 mg/kg. The study drug was prepared in 5 ml of saline and administered 10 minutes before the induction of general anesthesia. General anesthesia was induced with fentanyl, propofol and vecuronium and was maintained with N2O and enflurane. Postanesthetic recovery (PAR) scores were recorded after the arrival of the patients in the postanesthetic recovery room. Sedation was quantified before and after premedication and 60, 120 minutes after arriving in the postanesthetic recovery room, using the symbol-digit-modalities test (SDMT) and trail-making test (TMT). RESULTS: There were no significant differences between the two groups with respect to age, weight and anesthesia time. There were no significant differences in PAR scores or PAR-stay time between two groups. SDMT and TMT scores were significantly different 5 minutes after the study's drug administration, and 60 minutes after arrival in the postanesthetic recovery room between the two groups. The incidence of side effects was similar in both groups. CONCLUSIONS: Midazolam premedication proved effective in sedation and anxiolysis without prolonging postanesthetic recovery and discharge times for outpatient general anesthesia.

Trimethyltin-Induced Hippocampal Neurodegeneration is Possibly Mediated by Induction of Apoptosis

BACKGROUND: Trimethyltin (TMT) is a neurotoxicant which produces a distinct pattern of neuronal cell death in the hippocampus following systemic administration of a single dose. However, the mechanism of selective neuronal death remains unclear. We performed this study to elucidate the underlying mechanism of TMT-induced hippocampal neu-ronal death. METHODS: The effects of trimethyltin (8.0mg/kg, I.p., single dose) on the hippocampal neurons were investi-gated in terms of changes in the neurobehavioral status, histologic, and electron microscopc findings. RESULTS: Behaviorally, TMT treatment caused stereotypic limbic system dysfunction, i.e. tremors, spontaneous seizures, vocaliza-tion, hyperactivity, hyperexcitability, intraspecific aggression as described previously. Morphologically, TMT produced prominent neurodegeneration in the dentate gyrus. Widespread, strong glial fibrillary acidic protein (GFAP) immunore-activity, which was suggestive of reactive astrogliosis, was noted throughout the hippocampal subfields. Many degener-ating neurons were TUNEL positive. Electron microscopic findings revealed characteristic features of apoptosis in the dentate granule cells. NADPH-diaphorase positive cells were spared after TMT exposure. CONCLUSIONS: It is suggested that TMT-induced hippocampal degeneration might be a useful in vivo model for the study of learning and memory, neuronal-glial interactions, and selective neuronal apoptosis.

Trimethyltin-Induced Hippocampal Neurodegeneration is Possibly Mediated by Induction of Apoptosis

BACKGROUND: Trimethyltin (TMT) is a neurotoxicant which produces a distinct pattern of neuronal cell death in the hippocampus following systemic administration of a single dose. However, the mechanism of selective neuronal death remains unclear. We performed this study to elucidate the underlying mechanism of TMT-induced hippocampal neu-ronal death. METHODS: The effects of trimethyltin (8.0mg/kg, I.p., single dose) on the hippocampal neurons were investi-gated in terms of changes in the neurobehavioral status, histologic, and electron microscopc findings. RESULTS: Behaviorally, TMT treatment caused stereotypic limbic system dysfunction, i.e. tremors, spontaneous seizures, vocaliza-tion, hyperactivity, hyperexcitability, intraspecific aggression as described previously. Morphologically, TMT produced prominent neurodegeneration in the dentate gyrus. Widespread, strong glial fibrillary acidic protein (GFAP) immunore-activity, which was suggestive of reactive astrogliosis, was noted throughout the hippocampal subfields. Many degener-ating neurons were TUNEL positive. Electron microscopic findings revealed characteristic features of apoptosis in the dentate granule cells. NADPH-diaphorase positive cells were spared after TMT exposure. CONCLUSIONS: It is suggested that TMT-induced hippocampal degeneration might be a useful in vivo model for the study of learning and memory, neuronal-glial interactions, and selective neuronal apoptosis.