CMAP decrement as a potential diagnostic marker for ALS.

OBJECTIVE: We previously reported that decrement of compound muscle action potential (CMAP) by repetitive nerve stimulation (RNS) was greater in the median nerves than in the ulnar nerves of patients with amyotrophic lateral sclerosis (ALS). The aim of this study was to evaluate whether CMAP decrement by RNS is a feasible marker for the differentiation of ALS from other diseases. MATERIALS & METHODS: We performed RNS in the median and ulnar nerves of 51 patients with ALS and 40 patients with other diseases. RESULTS: The CMAP decrement was significantly greater in the median nerves of patients with ALS, compared to the disease control patients. In the median nerves of patients with ALS, CMAP decrement was significantly greater in the cervical region-onset group than in the other region-onset group. CONCLUSIONS: The finding of CMAP decrement in the median nerves can be useful for differentiating ALS patients with cervical region onset from other controls with active neuropathic diseases.

Anterior mediastinal solid tumours in adults: characterisation using dynamic contrast-enhanced MRI, diffusion-weighted MRI, and FDG-PET/CT.

AIM: To find significant parameters to characterise anterior mediastinal solid tumours in adults using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), diffusion-weighted MRI (DWI), and combined 2-[(18)F]-fluoro-2-deoxy-d-glucose positron-emission tomography/computed tomography (FDG-PET/CT). MATERIALS AND METHODS: Forty-eight histologically confirmed anterior mediastinal solid tumours in 48 patients (24 men, 24 women; age range 21-83 years, mean 50.7 years) were examined. The parameters analysed were maximal diameter, presence of capsule/septa on T2-weighted images, time-signal intensity curves (TICs), apparent diffusion coefficient (ADC), and maximum standardised uptake value (SUVmax). Also examined was whether any differences between histological types could be seen in these parameters. In a validation study, 42 anterior mediastinal solid tumours in 42 patients were examined consecutively. RESULTS: The washout pattern on TIC was seen only in thymic epithelial tumours (20/32). SUVmax of lymphoma (mean, 17.9), malignant germ cell tumours (14.2), and thymic carcinomas (15.6) were significantly higher than that of thymomas (6.1). The mean maximal diameter of thymic epithelial tumours was significantly smaller than that of lymphomas (p<0.01) and malignant germ cell tumours (p<0.05). The validation study also yielded high accuracy (38/42, 91%) in differentiation among the anterior mediastinal solid tumours. CONCLUSION: The SUVmax, TIC pattern on DCE-MRI, and maximal diameter might be useful to differentiate anterior mediastinal solid tumours in adults.

Performance of a rapid human metapneumovirus antigen test during an outbreak in a long-term care facility.

Using a newly developed rapid test, an outbreak of human metapneumovirus (HMPV) infection in a long-term care facility was detected within only 2 days after the onset of symptoms in a putative index case. The outbreak was almost under control within 8 days mainly by zoning patients, with the exception of two cases of HMPV that were diagnosed 16 and 17 days after the onset of the outbreak. According to an immunological diagnosis as well as the rapid test, it was eventually proven that 18 patients had HMPV infections. We suspected that even asymptomatic residents, who had not been completely separated from the facility population, were a source of infection. That suggested that all asymptomatic residents should be tested and that the separation of the infected patients should be absolute, if an outbreak of HMPV infection is suspected in such a facility.

Evaluation of the extent of ground-glass opacity on high-resolution CT in patients with interstitial pneumonia associated with systemic sclerosis: comparison between quantitative and qualitative analysis.

AIM: To verify whether quantitative analysis of the extent of ground-glass opacity (GGO) on high-resolution computed tomography (HRCT) could show a stronger correlation with the therapeutic response of interstitial pneumonia (IP) associated with systemic sclerosis (SSc) compared with qualitative analysis. MATERIALS AND METHODS: Seventeen patients with IP associated with SSc received autologous peripheral blood stem cell transplantation (auto-PBSCT) and were followed up using HRCT and pulmonary function tests. Two thoracic radiologists assessed the extent of GGO on HRCT using a workstation. Therapeutic effect was assessed using the change of vital capacity (VC) and diffusing capacity of the lung for carbon monoxide (DLco) before and 12 months after PBSCT. Interobserver agreement was assessed using Spearman's rank correlation coefficient and the Bland-Altman method. Correlation with the therapeutic response between quantitative and qualitative analysis was assessed with Pearson's correlation coefficients. RESULTS: Spearman's rank correlation coefficient showed good agreement, but Bland-Altman plots showed that proportional error could be suspected. Quantitative analysis showed stronger correlation than the qualitative analysis based on the relationships between the change in extent of GGO and VC, and change in extent of GGO and DLco. CONCLUSION: Quantitative analysis of the change in extent of GGO showed stronger correlation with the therapeutic response of IP with SSc after auto-PBSCT than with the qualitative analysis.

Hindered proton collectivity in 16(28)S12: possible magic number at Z=16.

The reduced transition probability B(E2;0(gs)(+)→2(1)(+)) for (28)S was obtained experimentally using Coulomb excitation at 53 MeV/nucleon. The resultant B(E2) value 181(31) e(2)fm(4) is smaller than the expectation based on empirical B(E2) systematics. The double ratio |M(n)/M(p)|/(N/Z) of the 0(gs)(+)→2(1)(+) transition in (28)S was determined to be 1.9(2) by evaluating the M(n) value from the known B(E2) value of the mirror nucleus (28)Mg, showing the hindrance of proton collectivity relative to that of neutrons. These results indicate the emergence of the magic number Z=16 in the |T(z)|=2 nucleus (28)S.

Endoscopic mucosal resection and endoscopic submucosal dissection for en bloc resection of superficial pharyngeal carcinomas.

BACKGROUND AND STUDY AIM: Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are being used increasingly to treat superficial oropharyngeal and hypopharyngeal carcinomas. The aim of this study was to clarify whether ESD provided better results than EMR for en bloc and complete resection of superficial pharyngeal carcinomas. PATIENTS AND METHODS: A total of 76 superficial pharyngeal carcinomas in 59 consecutively treated patients were included. Patients underwent either conventional EMR (using a transparent cap or strip biopsy) (n = 45 lesions) or ESD (n = 31 lesions) between October 2006 and January 2011. The rates of en bloc resection, complete resection (defined as en bloc resection with tumor-free margins), major complications, and local recurrence were evaluated retrospectively as the therapeutic outcomes. RESULTS: ESD yielded significantly higher rates of both en bloc and complete resection compared with EMR (en bloc 77.4 % [24/31] vs. 37.8 % [17/45], P = 0.0002; complete 54.8 % [17/31] vs. 28.9 % [13/45], P = 0.0379). ESD was more frequently complicated by severe laryngeal edema (4/21 [19.0 %] vs. 1/31 [3.2 %], P = 0.1446) and was also more time-consuming (124.9 ± 65.1 minutes vs. 57.2 ± 69.6 minutes; P = 0.0014). Local recurrence was observed more often after EMR than after ESD (3/45 [6.7 %] vs. 0/31 [0 %]), although this difference did not reach statistical significance (P = 0.2658). CONCLUSIONS: ESD appears to be a superior method of endoscopic resection of superficial pharyngeal carcinomas for achieving both en bloc and complete resection, although these benefits were also associated with a higher incidence of complications and a significantly longer procedure time. Large prospective studies are needed to compare ESD with conventional EMR for superficial pharyngeal carcinomas.

Randomized, double-blind, crossover, placebo-controlled clinical trial to evaluate the effects of chicken hot water extract on insulin secretion.

OBJECTIVE: Essence of chicken (EOC), a hot water extract of chicken, is widely consumed in Southeast Asia as a beverage. EOC has an inhibitory effect on the elevation of blood glucose levels and a secretagogue effect on insulin. However, the mechanism by which EOC promotes insulin secretion is unknown. We aimed to verify the postprandial hyperglycemic inhibitory effect and the insulin secretory effect of EOC in healthy adults under appropriate placebo settings. In addition, we aimed to understand the mechanism underlying the insulin secretory effect of EOC. PATIENTS AND METHODS: Thirty-four healthy Japanese adults were fed 68 mL of EOC or control food, followed by 200 g of cooked rice. Blood glucose and plasma insulin levels were measured at 30, 45, 60, 90, and 120 min after the participants ate cooked rice. The trial had a randomized, double-blind, crossover, placebo-controlled design. RESULTS: The ingestion of EOC induced an increase in the maximum blood concentration (Cmax) of insulin and shortened the time required to reach the maximum blood concentration following rice consumption. Ingestion of the test beverage resulted in a significantly higher insulinogenic index than that obtained after ingestion of the control beverage. No side effects were observed in this study. Mechanistic experiments revealed that EOC stimulated significant (p < 0.05) secretion of GLP-1 from NCI-H716 human intestinal L cells at 0.1, 1, and 10 mg/mL. CONCLUSIONS: Consuming EOC when eating rice supports pancreatic function. Daily consumption of EOC could elevate the early-phase insulin response; therefore, it could prevent diabetes in Asians with low insulin secretion.

Evaluation of the distribution and orientation of remineralized enamel crystallites in subsurface lesions by X-ray diffraction.

Remineralization is the process by which hydroxyapatite (HAp) is restored in enamel subsurface lesions, and transversal microradiography (TMR) has been used to analyze remineralization in terms of the recovery of mineral content. In this study, we directly detected the distribution and orientation of longitudinal HAp crystallite at the remineralized zone in enamel subsurface lesions by using an X-ray microbeam (6-mum diameter) diffraction method. This method was demonstrated and involves the simultaneous detection of wide-angle X-ray diffraction (WAXRD) and small-angle X-ray scattering (SAXS). WAXRD reflects the amount of HAp crystallites, and SAXS reflects that of voids in crystallites. The polished surface of a bovine enamel block was divided into three zones of sound, demineralized, and remineralized zones. Thin sections of approximately 150 mum thickness were then cut perpendicular to the surface, and subjected to WAXRD and SAXS following TMR. The increase in the amount of HAp crystallites and the decrease in voids in the crystallites at the remineralized zone were detected by WAXRD and SAXS, respectively, which was consistent with the result of TMR. This study indicates that both the spatial distribution and orientation of the restored HAp crystals in the remineralization process at the subsurface lesion can be simultaneously analyzed by the X-ray diffraction methods.

Nasal neuroendocrine carcinoma in a free-living Japanese raccoon dog (Nyctereutes procyonoides viverrinus).

Neuroendocrine carcinoma was diagnosed in the left nasal cavity of a free-living Japanese raccoon dog (Nyctereutes procyonoides viverrinus). Microscopically, the tumour consisted of sheets of anaplastic cells separated by narrow zones of fibrovascular stroma. The neoplastic cells had varying numbers of cytoplasmic granules stained by the Grimelius method. Immunohistochemically, the neoplastic cells were variably labelled for cytokeratin AE1/AE3, vimentin, chromogranin A and S-100. Ultrastructurally, some of the neoplastic cells had cytoplasmic membrane-bound dense-core granules of approximate diameter 140-240nm. The tumour had infiltrated the cerebrum and metastasized to the pituitary gland, mandibular and pulmonary lymph nodes, lungs, thyroid gland and adrenal glands.

Effect of rice-cooking water to the daily arsenic intake in Bangladesh: results of field surveys and rice-cooking experiments.

The effect of rice-cooking water to the daily arsenic intake of Bangladeshi people was investigated. At the first field survey, uncooked rice and cooked rice of 29 families were collected. Their arsenic concentrations were 0.22+/-0.11 and 0.26+/-0.15 mg/kg dry wt, respectively. In 15 families, arsenic concentration in rice increased after cooking. Good correlation (R(2)=0.89) was observed between arsenic in rice-cooking water and the difference of arsenic concentration in rice by cooking. In the second survey, we collected one-day duplicated food of 18 families. As a result, we estimated that six of 18 families likely used the arsenic contaminated water for cooking rice even they drank less arsenic-contaminated water for drinking purpose. We also conducted rice-cooking experiments in the laboratory, changing arsenic concentration in rice-cooking water. Clear linear relationships were obtained between the arsenic in rice-cooking water and the difference of arsenic concentration in rice by cooking. Factors that affect arsenic concentration in cooked rice are suggested as follows: (1) arsenic concentration in uncooked rice, (2) that in rice-cooking water, (3) difference in water content of rice before and after cooking, and (4) types of rice, especially, the difference between parboiled and non-parboiled rice.

Divergent cytotoxic effects of PKC412 in combination with conventional antileukemic agents in FLT3 mutation-positive versus -negative leukemia cell lines.

FMS-like tyrosine kinase-3 (FLT3) is a new therapeutic target for acute myelocytic leukemia (AML), because FLT3 mutations are the most common genetic alterations in AML and are directly related to leukemogenesis. We studied cytotoxic interactions of a FLT3 inhibitor, PKC412, with eight conventional antileukemic agents (cytarabine, doxorubicin, idarubicin, mitoxantrone, etoposide, 4-hydroperoxy-cyclophosphamide, methotrexate and vincristine) using three leukemia cell lines carrying FLT3 mutations (MOLM13, MOLM14 and MV4-11) and five leukemia cell lines without FLT3 mutations (KOPB-26, THP-1, BALL-1, KG-1 and U937). PKC412 showed synergistic effects with all agents studied except methotrexate for FLT3-mutated cell lines in isobologram analysis. In contrast, PKC412 was rather antagonistic to most drugs, except for 4-hydroperoxy-cyclophosphamide and vincristine, in leukemia cell lines without FLT3 mutations. Cell-cycle analysis revealed that PKC412 induced G1 arrest in leukemia cell lines carrying FLT3 mutations, whereas it arrested cells in G2/M phase in the absence of FLT3 mutations, which may underlie the divergent cytotoxic interactions. These results suggest that the simultaneous administration of PKC412 and other agents except methotrexate is clinically effective against FLT3 mutation-positive leukemias, whereas it would be of little benefit for FLT3 mutation-negative leukemias. Our findings may be of help for the design of PKC412-based combination chemotherapy.

Electronic ferroelectricity from charge ordering in RFe(2)O(4).

We report our recent discovery of novel ferroelectricity arising from the polar ordering of Fe(3)+ and Fe(2)+ in a mixed valence triangular lattice oxide LuFe(2)O(4), where the electric polarization is not a result of ionic displacement. The polar ordering of Fe(3)+ and Fe(2)+ was confirmed with a resonant x-ray scattering study in SPring-8. The origin of such ordering is the competitive interaction between Fe(3)+ and Fe(2)+ in the triangular lattice, i.e., the charge frustration. The polar superlattice of Fe(3)+ and Fe(2)+ develops below 350 K, where the electric polarization appears. The ferroelectricity arising from the polar charge ordering or the polar electron distribution may have great potential for the future application of ferroelectrics.

Integrin-linked kinase activity is associated with interleukin-1 alpha-induced progressive behavior of pancreatic cancer and poor patient survival.

Cancer cell adhesion and invasion into extracellular matrix are regulated by integrin-linked kinase (ILK) activity in a phosphatidylinositol 3-kinase (PI3-K)-dependent manner. In this study, we demonstrated that ILK and beta(1)-integrin play important roles in interleukin (IL)-1alpha-induced enhancement of adhesion and invasion of pancreatic cancer cells through p38 mitogen-activated protein kinase (MAPK) signaling pathway and activator protein-1 (AP-1) activation. Alteration of ILK kinase activity controlled IL-1alpha-induced p38 MAPK phosphorylation and its downstream AP-1 activation with subsequent regulation of pancreatic cancer cell adhesion and invasion. Overexpressed ILK enhances the IL-1alpha-induced p38 MAPK phosphorylation more strongly through glycogen synthase kinase 3 (GSK-3) activation, and subsequently induces AP-1 activation, which promotes aggressive capabilities of pancreatic cancer cells. In contrast, knockdown of ILK kinase activity inhibits the IL-1alpha-induced activation of MAPK/AP-1 pathway via inhibition of GSK-3 phosphorylation. In immunohistochemical analysis, statistically significant association between strong expression of ILK and poor prognosis of pancreatic cancer patients were observed, and strong expression of ILK in cancerous tissues can be a significant prognostic indicator of pancreatic cancer patients. Our results suggest that ILK is involved with aggressive capability in pancreatic cancer and that these regulations can be helpful to understand biological processes for a better translational treatment for pancreatic cancer patients.

Identification of a series of transforming growth factor beta-responsive genes by retrovirus-mediated gene trap screening.

Transforming growth factor beta (TGF-beta) plays important roles in the regulation of proliferation, differentiation, apoptosis, and carcinogenesis. To identify genes responsible for maintaining the phenotype induced by TGF-beta, we performed a retrovirus-mediated gene trap screening designed to isolate TGF-beta-responsive genes in human lung carcinoma cell line A549. After screening 249 trap lines, 21 were found to express the reporter beta-galactosidase gene in a TGF-beta-responsive manner. Interestingly, in large proportions of these trap lines, the reporter gene was responsive also to phorbol ester and was suppressed by gamma interferon. Fragments of all these trapped genes were recovered by 5'- and 3'-rapid amplification of cDNA ends (RACE), and in 15 out of 21 cases (71%), the TGF-beta responsiveness of the endogenous genes was confirmed by RNA blot hybridization. In at least five cases, the TGF-beta-induced upregulation was found to be cycloheximide resistant, suggesting the roles of the genes in the TGF-beta-induced primary responses. Sequence analyses revealed that 43% (9 of 21) of the trapped genes were novel and that the remainder included genes previously reported to be upregulated by TGF-beta, such as epidermal growth factor receptor and beta1 integrin, documenting the validity of this approach. Other known genes include the ones encoding the proteins associated with cell proliferation (ribosomal proteins S15a, hNRP/NAP-1, and lipocortin II), focal adhesions (paxillin), and transcriptional regulation (thyroid hormone receptor activator molecule 1 [TRAM-1]).

Stereotactic body radiation therapy (SBRT) for early-stage lung cancer.

Stereotactic body radiation therapy (SBRT) is a new treatment modality for early-stage non-small-cell lung cancer, and has been developed in the United States, the European Union, and Japan. We started a feasibility study of this therapy in July 1998, using a stereotactic body frame. The eligibility criteria for primary lung cancer were: 1) solitary tumor less than 4 cm (T1-3N0M); 2) inoperable, or the patient refused operation; 3) no necessity for oxygen support; 4) performance status equal to or less than 2; 5) the peripheral tumor which dose constraints of mediastinal organs are maintained. A total dose of 48 Gy was delivered in four fractions in 2 weeks in most patients. Lung toxicity was minimal. No grade II toxicities for spinal cord, bronchus, pulmonary artery, or esophagus were observed. The 3 years overall survival for 32 patients with stage IA, and 13 patients with stage IB were 83% and 72%, respectively. Only one local recurrence was observed in a follow-up of 6-71 months. We retrospectively analyzed 241 patients from 13 Japanese institutions. The local recurrence rate was 20% when the biological equivalent dose (BED) was less than 100 Gy, and 6.5% when the BED was over 100 Gy. Overall survival at 3 years was 42% when the BED was less than 100 Gy, and 46% when it was over l00 Gy. In tumors, which received a BED of more than 100 Gy, overall survival at 3 years was 91% for operable patients, and 50% for inoperable patients. Long-term results, in terms of local control, regional recurrence, survival, and complications, are not yet evaluated. However, this treatment modality is highly expected to be a standard treatment for inoperable patients, and it may be an alternative to lobectomy for operative patients. A prospective trial, which is now ongoing, will, answer these questions.

Different breakage-prone regions on chromosome 1 detected in t(11;14)-positive mantle cell lymphoma cell lines and multiple myeloma cell lines are associated with different tumor progression-related mechanisms.

To better define secondary aberrations that occur in addition to translocation t(11;14)(q13;q32) in mantle cell lymphomas (MCL) and in multiple myelomas (MM), seven t(11;14)-positive MCL cell lines and four t(11;14)-positive MM cell lines were analysed by fluorescence R-banding and spectral karyotyping (SKY). Compared with published data obtained by G-banding, most chromosome aberrations were redefined or further specified. Furthermore, several additional chromosome aberrations were identified. Thus, these cytogenetically well defined t(11;14)-positive MCL and MM cell lines may be useful tools for the identification and characterization of genes that might be involved in the pathogenesis of MCL and MM, respectively. Since MCL and MM were found to have different alterations of chromosome 1, these were investigated in more detail by fluorescence in situ hybridization (FISH) and multicolor banding (MCB) analyses. The most frequently altered and deletion-prone loci in MCL cell lines were regions 1p31 and 1p21. In contrast, breakpoints in MM cell lines most often involved the heterochromatic regions 1p12-->p11, and the subcentromeric regions 1q12 and 1q21. These data are in accordance with previously published data of primary lymphomas. Our findings may indicate that different pathways of clonal evolution are involved in these morphologically distinct lymphomas harboring an identical primary chromosome aberration, t(11;14).

Establishment of a hairy cell leukemia cell line carrying Tac antigen and phagocytic activity with B-cell characteristics.

A hairy cell leukemia cell line designated "Hair-M" was established in a suspension culture derived from the peripheral blood of an 86-year-old Japanese male with a diagnosis of hairy cell leukemia. The Hair-M cells were identified as having prominent hair-like cytoplasmic projections by examination with phase-contrast and scanning electron microscopy. These cells displayed ruffled membranes and stublike microvilli similar to those observed on the surfaces of cells in the peripheral blood of the patient. Immunologic and cytochemical studies on the Hair-M cells confirmed derivation from the clone of the patient's leukemia cells. Although the cultured Hair-M cells had definite B-cell characteristics, such as IgG kappa-chains on the surface and in cytoplasm, they also demonstrated Tac antigen, which is usually expressed on activated T-cells, and myelomonocyte antigens determined by OKM-1 and MCS-1 monoclonal antibodies. Other cell surface markers, including E(-), IgGFc(-), IgMFc(-), C3R(+), Ia-like antigen(+), OKT9(+), OKT10(+), and terminal deoxynucleotidyl transferase(-), were detected; no Epstein-Barr virus-determined nuclear antigen was detected. The karyotype of the Hair-M cells was determined to be 46XY with -11, -14, and two marker chromosomes. The Hair-M cells also had phagocytic activity to rabbit anti-human IgG serum-coated polyacrylamide gel particles.

Structurally altered Evi-1 protein generated in the 3q21q26 syndrome.

Overexpression of the Evi-1 gene appears to be a consistent feature of the 3q21q26 syndrome, an association of myeloid leukemias/myelodysplastic syndrome with a specific chromosomal aberration involving both 3q21 and 3q26, such as t(3;3)(q21;q26) or inv(3)(q21q26). The rearrangement in 3q26 has been reported to occur near the Evi-1 locus, implicating that it is the critical gene deregulated in the 3q21q26 syndrome. Here we present a structural abnormality of Evi-1 protein in a case with the 3q21q26 syndrome. In this case carrying typical inv(3)(q21q26), the 3q26 breakpoint is located within an intron of the Evi-1 gene, and resulted in overexpression of normally unexpressed, an aberrant form of Evi-1 protein, in which the C-terminal 44 amino acids of wild-type Evi-1 protein were truncated and replaced by five amino acids. The truncated Evi-1 protein is shown to increase AP1 activity when expressed in NIH3T3 cells as its wild-type counterpart. We also show that the origin of this peculiar type of rearrangement of the Evi-1 gene is not an artifact during establishment of the cell line, but is the event that occurred in the primary leukemic cells. Our results strongly support that the primary target for the 3q21q26 syndrome is the Evi-1 gene, and provide the first evidence that the structurally altered Evi-1 gene may be involved in the 3q21q26 syndrome.

The nucleotide and deduced amino acid sequences of a cDNA encoding a new species of pregnancy-specific beta 1-glycoprotein (PS beta G).

We screened a cDNA library of a human placenta with cDNA for nonspecific cross-reacting antigen, a member of the carcinoembryonic antigen gene family. One of the positive clones, PS34, was found to encode a 426 amino acid protein belonging to pregnancy-specific beta 1-glycoprotein (PS beta G). The mature PS34 protein consisted of domains, N, A1, A2, B2 and C. The domain-N of PS34 showed sequence similarities of 79.8-83.5% to those of the PS beta G members so far reported, indicating PS34 is a new member of PS beta G and also of the carcinoembryonic antigen gene family.

Combined antioxidant and COMT inhibitor treatment reverses renal abnormalities in diabetic rats.

The development and progression of diabetic nephropathy is dependent on glucose homeostasis and many other contributing factors. In the present study, we examined the effect of nitecapone, an inhibitor of the dopamine-metabolizing enzyme catechol-O-methyl transferase (COMT) and a potent antioxidant, on functional and cellular determinants of renal function in rats with streptozotocin-induced diabetes. Administration of nitecapone to diabetic rats normalized urinary sodium excretion in a manner consistent with the dopamine-dependent inhibition of proximal tubule Na,K-ATPase activity. Hyperfiltration, focal glomerulosclerosis, and albuminuria were also reversed by nitecapone, but in a manner that is more readily attributed to the antioxidant potential of the agent. A pattern of elevated oxidative stress, measured as CuZn superoxide dismutase gene expression and thiobarbituric acid-reactive substance content, was noted in diabetic rats, and both parameters were normalized by nitecapone treatment. In diabetic rats, activation of glomerular protein kinase C (PKC) was confirmed by isoform-specific translocation and Ser23 phosphorylation of the PKC substrate Na,K-ATPase. PKC-dependent changes in Na,K-ATPase phosphorylation were associated with decreased glomerular Na,K-ATPase activity. Nitecapone-treated diabetic rats were protected from these intracellular modifications. The combined results suggest that the COMT-inhibitory and antioxidant properties of nitecapone provide a protective therapy against the development of diabetic nephropathy.