[Photo-Degradation Mechanism and Pathway for Tetracycline in Simulated Seawater Under Irradiation of Visible Light].

To explore the mechanism and pathway for pollutant degradation in seawater by heterogeneous photocatalysts, the degradation of tetracycline (TC) in pure water and simulated seawater with different mesoporous TiO2 under the excitation of visible light was first investigated; then the effect of different salt ions on the photocatalytic degradation process was clarified. Combined with radical trapping experiments, electron spin resonance (ESR) spectroscopy, and intermediate product analysis, the main active species for photodegrading pollutants and the pathway of TC degradation in simulated seawater were investigated. The results showed that the photodegradation for TC in simulated seawater was significantly inhibited. Compared with the TC photodegradation in pure water, the reaction rate of the chiral mesoporous TiO2 photocatalyst for TC was reduced by approximately 70%, whereas the achiral mesoporous TiO2 photocatalyst could hardly degrade TC in seawater. Anions in simulated seawater had little effect on photodegradation, but Mg2+ and Ca2+ ions significantly inhibited the TC photodegradation process. Whether in water or simulated seawater, the active species generated by the catalyst after excitation by visible light were mainly holes, and each salt ion did not inhibit the generation of active species; thus, the degradation pathway both in simulated seawater and in water was the same. However, Mg2+ and Ca2+ would be enriched around the highly electronegative atoms in TC molecules, hindering the attack of holes to highly electronegative atoms in TC molecules, thereby inhibiting the photocatalytic degradation efficiency.

Contrasting effects of different light regimes on the photoreactivities of allochthonous and autochthonous chromophoric dissolved organic matter.

Chromophoric dissolved organic matter (CDOM) plays an important role in ultraviolet (UV) light absorption in the ocean. CDOM is known to originate from either an allochthonous or autochthonous source and has varying compositions and levels of reactivity; however, the effects of individual radiation treatments and the combined effects of UVA and UVB on allochthonous and autochthonous CDOM remain poorly understood. Thus, here, we measured changes in the common optical properties of CDOM collected from China's marginal seas and the Northwest Pacific, using full-spectrum, UVA (315-400 nm), and UVB (280-315 nm) irradiation to induce photodegradation over the same time period (60 h). Excitation-emission matrices (EEMs) combined with parallel factor analysis (PARAFAC) identified four components: marine humic-like C1, terrestrial humic-like C2, soil fulvic-like C3, and tryptophan-like C4. Although the behaviours of these components during full-spectrum irradiation exhibited similar decreasing tendencies, three components (C1, C3, and C4) underwent direct photodegradation under UVB exposure, whereas C2 was more susceptible to UVA degradation. The diverse photoreactivities of the source-dependent components to different light treatments led to differing photochemical behaviours of other optical indices [aCDOM(355), aCDOM(254), SR, HIX, and BIX]. The results indicate that irradiation preferentially reduced the high humification degree or humic substance content of allochthonous DOM, and promoted the transformation from the allochthonous humic DOM components to recently produced components. Although values for the samples from different sources overlapped frequently, principal component analysis (PCA) indicated that the overall optical signatures could be linked to the original CDOM source features. The degradation of CDOM humification, aromaticity, molecular weight, and autochthonous fractions under exposure can drive the CDOM biogeochemical cycle in marine environments. These findings can aid in a better understanding of the effects of different combinations of light treatments and CDOM characteristics on CDOM photochemical processes.

The Value of Enhanced MR Radiomics in Estimating the IDH1 Genotype in High-Grade Gliomas.

BACKGROUND: The prognosis of IDH1-mutant glioma is significantly better than that of wild-type glioma, and the preoperative identification of IDH mutations in glioma is essential for the formulation of surgical procedures and prognostic assessment. PURPOSE: To explore the value of a radiomic model based on preoperative-enhanced MR images in the assessment of the IDH1 genotype in high-grade glioma. MATERIALS AND METHODS: A retrospective analysis was performed on 182 patients with high-grade glioma confirmed by surgical pathology between December 2012 and January 2019 in our hospital with complete preoperative brain-enhanced MR images, including 79 patients with an IDH1 mutation (45 patients with WHO grade III and 34 patients with WHO grade IV) and 103 patients with wild-type IDH1 (33 patients with WHO grade III and 70 patients with WHO grade IV). Patients were divided into a primary dataset and a validation dataset at a ratio of 7 : 3 using a stratified random sampling; radiomic features were extracted using A.K. (Analysis Kit, GE Healthcare) software and were initially reduced using the Kruskal-Wallis and Spearman analyses. Lasso was finally conducted to obtain the optimized subset of the feature to build the radiomic model, and the model was then tested with cross-validation. ROC (receiver operating characteristic curve) analysis was performed to evaluate the performance of the model. RESULTS: The radiomic model showed good discrimination in both the primary dataset (AUC = 0.87, 95% CI: 0.754 to 0.855, ACC = 0.798, sensitivity = 85.5%, specificity = 75.4%, positive predictive value = 0.734, and negative predictive value = 0.867) and the validation dataset (AUC = 0.86, 95% CI: 0.690 to 0.913, ACC = 0.789, sensitivity = 91.3%, specificity = 69.0%, positive predictive value = 0.700, and negative predictive value = 0.909). CONCLUSION: The radiomic model, based on the preoperative-enhanced MR, can effectively predict the IDH1 genotype in high-grade glioma.

The clinical presentation and collateral pathway development of congenital absence of the internal carotid artery.

OBJECTIVE: The objective of this study was to investigate the clinical presentation, risks, and collateral pathway development of the congenital absence of the internal carotid artery (ICA). METHODS: Sixty-four patients (10 new patients and 54 patients from the relevant literature) were studied. Data on demographic, clinical, and radiologic features were collected, followed by an analysis of the risks associated with ICA agenesis. RESULTS: There were 31 male and 33 female patients whose ages ranged from 5 months to 75 years, with a mean age of 31.1 years. The range of clinical symptoms recorded included transient ischemic attack (17 patients), subarachnoid hemorrhage (12 patients), developmental delay (13 patients), asymptomatic (8 patients), and other symptoms (15 patients). All 64 patients presented with absence of unilateral or bilateral ICAs, as measured by cervical computed tomography angiography or magnetic resonance angiography. The carotid canal was absent in all patients on computed tomography of the base of the skull, and abnormal development of collateral circulation pathways was observed. Five patients presented with basilar artery dilation on angiography. Aneurysms were observed in the angiography results from 16 patients. Ten patients presented with variations in the ophthalmic artery origin (the ophthalmic artery originated from the ipsilateral middle meningeal artery in six patients and from the ipsilateral middle cerebral artery in four patients). CONCLUSIONS: From analysis of our 10 cases of ICA agenesis and our review of the relevant literature, we conclude that young patients with ICA agenesis may present with developmental delay, subarachnoid hemorrhage, or other developmental abnormalities, whereas older patients most commonly present with transient neurologic events. Complications of carotid agenesis are related to specific anatomic subtypes and the resulting collateral circulation development.

[Diagnostic Value of Immunofixation Electrophoresis and KAP/LAM Ratio in Multiple Myeloma Patients with Renal Injury].

OBJECTIVES: To explore the diagnostic value of immunofixation electrophoresis and Kappa/Lambda (KAP/LAM) ratio in multiple myeloma patients with renal injury. METHODS: The serum of 822 patients of renal disease were collected for the examnation of immunofixation electrophoresis, KAP/LAM ratio, serum immunoglobulin levels and renal function, including serum urea nitrogen (BUN), serum creatinine (Crea), cystatin C (Cys-C) and estimated glomerular filtration rate (eGFR). To analyze the diagnostic value of immunofixation and KAP/LAM ratio in the differentiation of renal injury of multiple myeloma from primary renal injury diseases. RESULTS: M protein was observed in 75 patients (9.1%). The ratio of each type was IgG 49.3%(37/75), IgA 34.7%(26/75), IgM 5.3%(4/75) and LAM 10.7%(8/75). There was significant difference of KAP/LAM ratio between M protein group and non-M protein group. The KAP/LAM ratio was significant higher in KAP group, compared to non-M protein group. Reverse result was obtained in LAM group. There were higher Crea level and lower eGFR value in pure LAM light chain group, compared with IgG, IgA and IgM groups. CONCLUSIONS: Immunofixation electrophoresis and KAP/LAM ratio may play an important role in the diagnosis of multiple myeloma patients with renal injury, so could be early screening markers.

Determination of galangin in rat plasma by UPLC and pharmacokinetic study.

In this study, a simple, sensitive, and robust analytical method based on ultra-performance liquid chromatography (UPLC) has been developed for the determination of galangin in rat plasma using diazepam as internal standard (IS). After sample preparation by a simple liquid-liquid extraction, chromatography was performed on an Acquity UPLC BEH C18 column (2.1mm×50mm, 1.7µm particle size) and ultraviolet detection set at a wavelength of 360nm. The method was linear over the concentration range 10-1000ng/mL with a lower limit of quantification (LLOQ) of 10ng/mL. Inter- and intra-day precision (RSD %) were all within 9.5% and the accuracy (RE %) was equal or lower than 8.9%. Recoveries of galangin and IS were more than 78.3%. Stability studies showed that galangin was stable under a variety of storage conditions. The method was successfully applied to a pharmacokinetic study involving oral administration of galangin to rats.

Lobaplatin combined floxuridine/pirarubicin-based transcatheter hepatic arterial chemoembolization for unresectable primary hepatocellular carcinoma.

PURPOSE: To assess the effect and safety of lobaplatin combinated floxuridine /pirarubicin in transcatheter hepatic arterial chemoembolization(TACE) of unresectable primary liver cancer. PATIENTS AND METHODS: TACE combined with the chemotherapy regimen was used to treat 34 unresectable primary liver cancer patients. DSA/ MRI/CT/blood routine examinations were used to evaluate short term activity and toxicity after 4-5 weeks, the process being repeated if necessary. RESULTS: Among the 34 cases, 1 (2.9%) showed a complete response, 21 (61.7%) a partial response, 8 (23.5%) stable disease, and 4 progressive disease, with a total effective rate of 67.6%. The content of alpha fetoprotein dropped by over 50% in 20 cases (58.8%). The rate of recovery was hepatalgia (88.2%), ascites (47.1%), appetite (55.9%), Performance Status(30.4%). The median follow-up time (MFT) was 281 days (63-558 days), and median progression-free survival was 118.5 days (95%, CI:88.8-148.2 days). Adverse reactions (III-IV grade) were not common, with only 4 cases of vomiting and 2 cases of thrombocytopenia (III grade). CONCLUSIONS: Lobaplatin-based TACE is an effective and safe treatment for primary liver cancer.

Does the expression of versican isoforms contribute to the pathogenesis of neurodegenerative diseases?

Classical neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's are most commonly seen in older persons. The incidence rate increases as life expectancy increases. Even though neuronal loss, neuronal death and accumulated toxic proteins are well investigated, the mechanism(s) of neurodegenerative disorders is not yet fully understood. Versican is a large extracellular matrix proteoglycan. Its isoforms are aberrantly expressed in central nervous system injuries. Diverse lines of evidence suggest that versican isoforms play a vital role in regulating neuronal differentiation, maturation, neurite outgrowth, and synaptic transmission. Some toxic proteins may be increased and less sensitive to degeneration due to the chondroitin sulfate (CS) chains of versicans. We propose that the patterns of versican V1 and V2 isoforms act as a fine-tuned mechanism for guiding the change of neural microenvironment, and the unbalanced expression of V1 and V2 isoforms may contribute to the pathogenesis of neurodegenerative diseases. The emergence of versican isoforms indicates that it may explain the pathogenesis of the common sporadic forms of complex diseases.

[Analysis of frequency of peripheral blood CD4+; CD25(high);Tregs and CD4+; CD25(low);T cells and expression of PD-1 in SLE and RA patients].

AIM: To explore the frequencies of peripheral blood CD4(+);CD25(high);Treg and CD4(+);CD25(low);T cells and the expression of the co-stimulatory molecule PD-1 on these two group cells surface in SLE and RA patients, and to explore their roles in cell immunity disorder of SLE and RA. METHODS: Flow cytometry (FCM) was used to determine the frequencies of peripheral blood CD4(+);CD25(high);Treg and CD4(+);CD25(low);T cells, and the expression percentage of PD-1. RESULTS: Compared with healthy control, the frequencies of peripheral blood CD4(+);CD25(high);Treg from both SLE and RA patients groups decreased significantly(P<0.05). Compared between two disease groups, the frequency of peripheral blood CD4(+);CD25(high);Treg in SLE patients was significantly lower(P<0.05). The expression percentage of PD-1 on CD4(+);CD25(high);Treg surface in RA group was obviously lower than that in both healthy control and SLE patients groups(P<0.05), while the percentage had no significant difference between SLE patients and healthy control(P>0.05). There was no significant difference in both the frequency of CD4(+);CD25(low);T cells and the expression percentage of PD-1 on this subset cells among three groups. CONCLUSION: The weakened ability of peripheral blood CD4(+);CD25(high);Treg to suppress effector T cells resulted from their production deficiency is the common characteristic of SLE and RA patients. Decreased expression of PD-1 is the primary cause leading to the suppressive function of peripheral blood CD4(+);CD25(high);Treg weakened in RA patients. However, PD-1 does not play major role in weakening the suppression activity of CD4(+);CD25(high);Treg from SLE patients.

[Study on ratio imbalance of peripheral blood Th17/Treg cells in patients with rheumatoid arthritis].

AIM: To observe the relationship between balance of peripheral blood Th17 cells and Foxp3(+) CD4(+) CD25(+) regulatory T (Treg) cells in patients with rheumatoid arthritis (RA), and to clarify the role the ratio imbalance of peripheral blood Th17/Treg cells playing in pathogenesis of RA. METHODS: The ratio of peripheral blood Th17 cells and Foxp3(+) CD4(+) CD25(+) Treg cells in RA patients and healthy subjects were determined by flow cytometry (FCM). RESULTS: Compared with healthy controls, the ratio of both CD3(+) CD4(+) T cells and Th17 cells in RA patients increased significantly (P<0.05), while the percentage of Foxp3(+) CD4(+) CD25(+) Treg cells was markedly lower (P<0.05). With the development of RA activity, the ratio of Th17 cells increased (P<0.05), and the ratio of Foxp3(+) CD4(+) CD25(+) Treg cells decreased (P>0.05). CONCLUSION: The disorder of peripheral blood T lymphocyte subsets in RA patients characterized by increased CD4(+) T cells. The imbalance between Th17 cells and Foxp3(+) CD4(+) CD25(+) Treg cells resulted from increased ratio of Th17 cells and decreased ratio of Foxp3(+) CD4(+) CD25(+) Treg cells may play a critical role in RA progression.

[Promising diagnostic model for systemic lupus erythematosus using proteomic fingerprint technology].

OBJECTIVE: To establish a diagnostic model for systemic lupus erythematosus (SLE) using proteiomic fingerprint techology. METHODS: Blood samples were collected from 64 cases of SLE, 30 cases of rheumatoid arthritis (RA), 30 cases of Sjogren's syndrome (SS), 25 cases of systemic sclerosis (SSc), as well as 83 healthy controls. Proteomic spectra of these 232 serum samples were generated by proteomic fingerprint technology. Diagnostic model was established by a machine learning algorithm called decision boosting. The sensitivity and specificity of the diagnostic model was validated with a blinded testing set. RESULTS: Sixty differential protein peaks (P<0.05) between SLE and control subjects were indicated, 28 of them were up regulated and 32 were down regulated in SLE patients. The algorithm identified a cluster pattern segregating SLE from non-SLE with sensitivity of 91% and specificity of 92%. The discriminatory diagnostic pattern correctly identified SLE. A sensitivity of 78% and specificity of 96% for the blinded test were obtained when comparing SLE vs non-SLE. CONCLUSION: This diagnostic model using proteiomic fingerprint techology appears to be a promising tools with high sensitivity and specificity in diagnosis of SLE.

[Lymphoplasmacytic lymphoma with Waldenström's macroglobulinemia: a clinicopathological and immunophenotypic study of 40 Chinese patients].

OBJECTIVE: To investigate the clinicopathologic features of lymphoplasmacytic lymphoma (LPL) with Waldenström's macroglobulinemia (WM) and to evaluate the usefulness of immunophenotype analysis in diagnosis and differential diagnosis of the tumor. METHODS: A total of 40 cases of LPL with WM diagnosed according to the 2008 World Health Organization classification of tumors of hematopoietic and lymphoid tissues were analyzed using immunophenotype and follow-up information. RESULTS: The mostly common initial clinical presentations were non-specific symptoms, such as fatigue, anemia and hemorrhage. Lymphadenopathy, splenomegaly and hepatomegaly were found in 42.5%, 20.0% and 12.5% of the patients respectively. The pattern of bone marrow involvement included mixed type (47.2%), diffuse type (41.7%) and interstitial type (11.1%). The nodal architecture was completely destroyed in one case and partially effaced with residual germinal centers and dilated sinuses in 8 cases. All of the neoplastic cells expressed CD20 and CD79a. Neoplastic plasma cells were positive for CD138 and CD79a. No cases expressed CD5. Four cases weakly expressed CD23. No significant prognosis related factors were identified in the survival analysis. CONCLUSIONS: LPL with WM is a rare indolent small B-cell lymphoma, which is commonly seen, in older male patients. The tumor frequently involves bone marrow and shows various clinical manifestations. Combination analyses of the bone marrow biopsy histology, immunophenotypic study and clinical data, especially the serum examination are important for the diagnosis of LPL with WM.

[Regulatory function of tacrolimus and CsA on CD4/CD8 T lymphocyte subgroups and costimulators on them in allo-liver recipients].

AIM: To explore the regulatory function of FK506 and CsA on CD4/CD8 T lymphocyte subgroups and co-stimulators on them. METHODS: The fluorescein-labelled monoclonal antibodies and flowcytometer were used to determine the T-lymphocyte subgroups and the expression of CD28, CD152 and ICOS on them in allo-liver recipients treated with FK506 or CsA at the end of 2 months after transplantation and treatment. Healthy volunteers and the patients who suffered from severe hepatic diseases and would receive liver transplantation were used as controls. RESULTS: In disease-control group, the balance of T cell subgroups was disturbed and the expression of co-stimulators was abnormal. In liver recipients receiving immunosuppressive therapy, the expression of T-cell subgroups returned to the normal level, the expressions of CD28 and ICOS on T cells decreased significantly (P<0.05), while the expression of CD152 on T cells increased significantly (P<0.05). Between two treatment group, the expression of CD4(+)T cells and the expression of CD28 and ICOS on CD8(+)T cells in CsA-treated group were much higher than those in FK506-treated group (P<0.05), and there was no significant difference between two treatment groups in other indexes. CONCLUSION: At routine blood concentration, there is some difference in the regulatory effect of FK506 and CsA on T-cell subgroups and the expression of co-stimulators on T cells. The regulatory effect of FK506 on T-cell subgroups is stronger than that of CsA. FK506 can not only inhibit the expression of positive co-stimulatory molecules CD28 and ICOS but also promote the expression of negative co-stimulatory molecule CD152, while CsA can exert its immunosuppressive effect mainly through promoting the expression of CD152.

[Analysis of Foxp3+ CD4+ CD25+ regulatory cells in peripheral blood of patients with SLE].

AIM: To investigate the expression of GITR on T cells and the expression of Foxp3(+) CD4(+) CD25(+) regulatory T cells in the peripheral blood of patients with SLE. METHODS: The expression of GITR and Foxp3(+) CD4(+) CD25(+) regulatory T cells in the peripheral blood was determined by flow cytometry(FCM). RESULTS: Compared with health control, the expression of Foxp3(+) CD4(+) CD25(+) regulatory T cells in peripheral blood from SLE patients was lower (P<0.05), but there is no difference in the expression of Foxp3(+) CD4(+) CD25(+) regulatory T cells between active and inactive SLE patients (P>0.05). GITR expression on both CD3(+) CD4(+) T cells and CD3(+) CD8(+) T cells of SLE patients increased significantly (P>0.05). With the development of SLE activity, GITR expression didn't change significantly on both CD3(+) CD4(+) T cells (P>0.05) and CD3(+) CD8(+) T cells (P>0.05). CONCLUSION: The expression abnormality of both Foxp3(+) CD4(+) CD25(+) regulatory cells and GITR may play important role in the imbalance of immune homeostasis in SLE.

[Role of Fas-FasL and caspase-3 signal transduction pathway in promoting apoptosis of T lymphocyte subset in SLE patients].

AIM: To explore the relationship between Fas-FasL-mediated signal transduction pathway and apoptosis disorder of T lymphocyte subset in SLE patients. METHODS: The expression rate of membrane Fas, FasL and that of intracellular activated caspase-3 of T lymphocyte subset were determined by flow cytometry. RESULTS: Compared with healthy control group, the expression rate of membrane Fas on CD4(+) T cells significantly increased in SLE patients in the active and inactive phases (P<0.05), however, that on CD8(+) T cells slightly increased but there was no statistical significance (P>0.05). The expression rate of FasL on T cell subset in SLE patients in the active and inactive phases significantly increased (P<0.05) but there was no obvious difference of the expression rate of Fas and FasL on T cell subset between the two disease groups (P>0.05). The expression rate of intracellular activated caspase-3 in T cell subset of SLE patients in the active phase was notably higher than that in the inactive phase and healthy control group (P<0.05). The expression rate of intracellular activated caspase-3 in T cell subset of SLE patients in the inactive phase was slightly higher than that in health control group but there was no statistical significance. CONCLUSION: Apoptotic speed of T lymphocyte subset in SLE patients was accelerated while CD4(+) T cells were in a state of active apoptosis. It is possible that Fas-FasL signal transduction pathway plays an important role in the induction of T cell apoptosis. The degree of apoptosis of T lymphocytes closely correlates with the disease's activity in SLE patients.

[Development of proteome two-dimensional electrophoresis technology].

Two-dimensional electrophoresis (2-DE) is the core technology of proteome study. This paper mainly introduces the 2-DE principle, sample preparation and usual methods to improve its resolving power. Furthermore, isoelectric focusing, SDS-PAGE electrophoresis and 2-DE staining methods are also reviewed.

Expression of metallothionein gene at different time in testicular interstitial cells and liver of rats treated with cadmium.

AIM: Rodent testes are generally more susceptible to cadmium (Cd)-induced toxicity than liver. To clarify the molecular mechanism of Cd-induced toxicity in testes, we compared metallothionein (MT) gene expression, MT protein accumulation, and Cd retention at different time in freshly isolated testicular interstitial cells and liver of rats treated with Cd. METHODS: Adult male Sprague-Dawley rats weighing 250-280 g received a s.c injection of 4.0 micromol Cd/kg and were euthanized by CO(2) asphyxiation 1 h, 3 h, 6 h, or 24 h later. Tissue was sampled and testicular interstitial cells were isolated. There were three replicates per treatment and 3 animals per replicate for RNA analyses, others, three replicates per treatment and one animal per replicate. MT1 and MT2 mRNA levels were determined by semi-quantitative RT-PCR analysis followed by densitometry scanning, and MT was estimated by the enzyme-linked immunosorbent assay (ELISA) method. Cadmium content was determined by atomic absorption spectrophotometry. The same parametersd were also analyzed in the liver, since this tissue unquestionably accumulate MT. RESULTS: The rat testis expressed MT1 and MT2, the major isoforms. We also found that untreated animals contained relatively high basal levels of both isoform mRNA, which were increased after Cd treatment in liver and peaked at 3 h, followed by a decline. In contrast, the mRNA levels in interstitial cells peaked at 6 h. Interestingly, the induction of MT1 mRNA was lower than MT2 mRNA in liver of rat treated with Cd, but it was opposite to interstitial cells. Cd exposure substantially increased hepatic MT (3.9-fold increase), but did not increase MT translation in interstitial cells. CONCLUSION: Cd-induced expression of MT isoforms is not only tissue dependent but also time-dependent. The inability to induce the metal-detoxicating MT-protein in response to Cd, may account for a higher susceptibility of testes to Cd toxicity and carcinogenesis compared to liver.

Metallothionein gene expression under different time in testicular Sertoli and spermatogenic cells of rats treated with cadmium.

The rodent testes are generally more susceptible to cadmium (Cd)-induced toxicity than the liver. To clarify the molecular mechanism underlying tissue and cell differences in Cd sensitivity, we compared metallothionein (MT) gene expression, MT protein accumulation, and Cd retention under different times in freshly isolated testicular Sertoli and spermatogenic cells and liver of rats treated with Cd. Adult male Sprague-Dawley rats received a s.c. injection of 4.0 micromol Cd/kg and 1, 3, 6, or 24h later and untreated animals (0h) tissue were sampled and testicular Sertoli and spermatogenic cells isolated. MT1 and MT2 mRNA levels were determined by semi-quantitative RT-PCR analysis followed by densitometry scanning, and MT was estimated by the enzyme-linked immunosorbent assay (ELISA) method. Cadmium content was determined by atomic absorption spectrophotometry. Testicular lesions were not grossly or histologically observed in rats treated with 4.0 micromol Cd/kg. In the present study, we demonstrated that the rat testis indeed expressed MT1 and MT2, the major isoforms. We also found that untreated animals contained relatively high basal levels of both isoform mRNA, which were increased after Cd treatment in liver and peaked at 3h, followed by a decline, in contrast, the mRNA levels in Sertoli cells peaked at 6h. Interestingly, the induction of MT1 mRNA was lower than MT2 mRNA in Sertoli cells and liver of rats treated with Cd. However, the MT1 mRNA levels of spermatogenic cells decreased 0-3h after Cd treatment, followed by an increase; in contrast, MT2 mRNA levels increased 0-3h after Cd treatment, followed by a reduction, but induced extents of them are lower than those of Sertoli cells and liver. Cd exposure substantially increased hepatic MT, but did not increase MT translation in Sertoli and spermatogenic cells. These results indicate: (1) that Cd-induced MT mRNA expression is cell- and time-dependent; (2) that the inability to induce the metal-detoxicating MT protein in response to Cd, might account for higher susceptibility of testes to Cd toxicity and carcinogenesis relative to liver.