Prognostic value of power doppler ultrasonography for equine superficial digital flexor tendon injury in thoroughbred racehorses.

The potential value of hypervascularity detected with power Doppler ultrasonography (PDU) within equine superficial digital flexor tendon (SDFT) as a prognostic factor of SDFT injury is not clear. The purpose of this study was to test the hypothesis that hypervascularity within SDFT is one of the risk factors for subsequent severe SDFT injury and to evaluate the prognostic value. A prospective cohort study of 97 Thoroughbred racehorses without any clinical signs of SDFT injury was conducted. Six variables of age, body weight, sex, the cross-sectional area of SDFT, PDU signal within SDFT and experience of steeplechase were assessed for the possibility of risk factors of subsequent SDFT injury in follow-up period of 1 year. Multivariable logistic regression analyses were used for assessment of the odds ratios (ORs) and 95 % confidence intervals (CIs) of SDFT injury. Multivariable logistic regression analysis revealed that the PDU signal within SDFT was a risk factor for the development of SDFT injury in follow-up period (P = 0.017). The adjusted OR of SDFT injury was significantly higher in PDU positive group than in PDU negative group (OR 3.17, 95 % CIs 1.20-8.35). Although further studies are required, these results would be useful for early detection and/or prevention of development for clinical severe SDFT injury.

Brain tissue water comes in two pools: evidence from diffusion and R2' measurements with USPIOs in non human primates.

Diffusion-weighted MRI of non-human primates revealed that USPIO Bulk Magnetic Susceptibility (BMS) T2' effects of Ultrasmall Superparamagnetic Particles with Iron Oxide (USPIO) in the brain cannot be explained by a single compartment model, as diffusion and T2' effects appear coupled: Apparent Diffusion Coefficient (ADC) values depend on USPIO concentration and relaxivity effects of USPIO decrease with the b value. On the other hand, USPIO and diffusion effects could be well uncoupled using a model consisting in a fast and a slow diffusion pool with different relaxivities. Diffusion-weighting acts as a filter which emphasizes the contribution of the slow pool when increasing b values (apparent decrease in ADC and R2'). Those results have implications for human studies using BMS contrast agents, as well as BOLD and diffusion fMRI.

Diffusion tensor fiber tractography for arteriovenous malformations: quantitative analyses to evaluate the corticospinal tract and optic radiation.

BACKGROUND AND PURPOSE: We hypothesized that diffusion tensor fiber tractography would be affected by intracranial arteriovenous malformation (AVM). The purpose of the present study was to evaluate the influence of intracranial AVM on corticospinal tract and optic radiation tractography. MATERIALS AND METHODS: The subject group comprised 34 patients with untreated intracranial AVM. Hemorrhage was present in 13 patients and absent in 21 patients. Perinidal fractional anisotropy (FA) and number of voxels along the reconstructed corticospinal and optic radiation tracts were measured, and left-to-right asymmetry indices (AIs) for those values were quantified. Patients were assigned to 1 of 3 groups: tracts distant from nidus, tracts close to nidus without neurologic symptoms, and tracts close to nidus associated with neurologic symptoms. One-way analysis of variance was used to compare differences in AI between groups. Hemorrhagic and nonhemorrhagic groups were assessed separately. RESULTS: In patients without hemorrhage, AI of optic radiation volume (P<.0001), AI of perinidal FA along corticospinal tract (P=.006), and optic radiation (P=.01) differed significantly between groups. In patients associated with hemorrhage, AI of corticospinal tract volume (P=.01), AI of perinidal FA along corticospinal tract (P=.04), and optic radiation (P=.004) differed significantly between groups. CONCLUSIONS: Corticospinal tract and optic radiation tractography were visualized in patients with AVM. In patients with both hemorrhagic and nonhemorrhagic AVM, the 2 fiber tracts close to the nidus were less visualized in the affected hemisphere than those distant from the nidus. Tracts were less visualized in patients with neurologic symptoms than in asymptomatic patients.

Diffusion tensor fiber tractography of the optic radiation: analysis with 6-, 12-, 40-, and 81-directional motion-probing gradients, a preliminary study.

BACKGROUND AND PURPOSE: Knowing the exact location of the optic radiation preoperatively is important for surgery of the temporal lobe. We hypothesized that a greater number of motion-probing gradients (MPGs) would provide better results of diffusion tensor (DT) fiber tractography of the optic radiation. To test this hypothesis, this study evaluated differences in DT fiber tractography of the optic radiation under different MPG settings. METHODS: DT images were obtained in 12 healthy volunteers (7 men, 5 women) with a mean age of 32 years (range, 22-45 years) by using a 3T MR imaging scanner with single-shot echo-planar imaging with parallel acquisition (reduction factor = 2). MPG was applied in 6, 12, 40, and 81 independent directions. The first region of interest (ROI) was placed in the occipital lobe, and the second ROI was placed in the lateral geniculate body. Fibers penetrating both ROIs were considered as the optic radiation. Anteroposterior distance between the tip of the Meyer loop and the lateral geniculate body on an axial section was defined as a loop index. Numbers of fibers and loop indices in both cerebral hemispheres were evaluated statistically. RESULTS: The optic radiation was well visualized in full length by DT fiber tractography in 20 of 24 hemispheres (83%). No significant differences were noted in number of fibers and loop indices among different MPG settings. CONCLUSION: DT fiber tractography can frequently depict almost the entire optic radiation. MPG number does not exert any significant effect on visualization of the optic radiation, and 6-directional MPG is thus sufficient for this purpose.

Language control in the bilingual brain.

How does the bilingual brain distinguish and control which language is in use? Previous functional imaging experiments have not been able to answer this question because proficient bilinguals activate the same brain regions irrespective of the language being tested. Here, we reveal that neuronal responses within the left caudate are sensitive to changes in the language or the meaning of words. By demonstrating this effect in populations of German-English and Japanese-English bilinguals, we suggest that the left caudate plays a universal role in monitoring and controlling the language in use.

Extended flexible sigmoidoscopy performed by colonoscopists for colorectal cancer screening: a pilot study.

BACKGROUND: Caecal intubation can be achieved by extended flexible sigmoidoscopy in 32% of patients. AIM: To assess the feasibility of extended flexible sigmoidoscopy performed by colonoscopists for colorectal cancer screening. METHODS: We enrolled 41 patients referred for screening flexible sigmoidoscopy. After purging, examination was performed with a colonoscope. All patients completed sigmoidoscopy (success in meeting referral goal); 93% and 71% had examination to the transverse or ascending colon, and caecum, respectively. Overall yield and right-sided polyps was 56% and 27%, respectively. Caecal intubation and complete examination with polypectomy took 6.0 +/- 2.5 and 18.3 +/- 5.1 min, respectively; with no complications. Twelve patients requested colonoscope withdrawal because of discomfort. Although 46% reported moderate to severe discomfort, 39% and 36%, respectively, were definitely or probably willing to repeat flexible sigmoidoscopy. RESULTS: Unsedated colonoscopy introduced as extended flexible sigmoidoscopy emphasizes the benefits of added yield rather than the negative image of withholding of discomfort relief. The patient can choose to accept the equivalent of an unsedated colonoscopy or reject the option based on perceived discomfort during extended flexible sigmoidoscopy performed by the colonoscopist. CONCLUSION: Extended flexible sigmoidoscopy is a feasible option in carefully selected patients, fully prepared and by an experienced colonoscopist.

Anti-apoptogenic function of TGFbeta1 for human synovial cells: TGFbeta1 protects cultured synovial cells from mitochondrial perturbation induced by several apoptogenic stimuli.

OBJECTIVE: To investigate anti-apoptogenic mechanism of transforming growth factor beta1 (TGFbeta1) towards synovial cells. METHODS: Isolated synovial cells, treated or not with TGFbeta1, were cultured in the presence or absence of anti-Fas IgM, proteasome inhibitor Z-Leu-Leu-Leu-aldehyde (LLL-CHO), etoposide, or C2-ceramide. After cultivation, apoptosis of synovial cells was examined by the presence of hypodiploid DNA(+) cells, the presence of terminal deoxy (d)-UTP nick end labelling(+) cells (TUNEL(+) cells), activation of caspases, and disruption of mitochondrial transmembrane potential (DeltaPsim). RESULTS: Activation of caspase-9 and DeltaPsim was found in anti-Fas IgM treated synovial cells. The increment of both hypodiploid DNA(+) cells and TUNEL(+) cells accompanied by the activation of caspase-8 and caspase-3 was also determined in anti-Fas IgM treated synovial cells. These hallmarks for apoptosis induced by anti-Fas IgM were significantly suppressed in TGFbeta1 treated synovial cells. LLL-CHO, etoposide, and C2-ceramide also caused DeltaPsim, the increment of both hypodiploid DNA(+) cells and TUNEL(+) cells, and the activation of both Leu-Glu-His-Asp ase (LEHDase; caspase-9 like activity) and Asp-Glu-Val-Asp ase (DEVDase; caspase-3 like activity) in synovial cells. As determined in anti-Fas IgM treatment, TGFbeta1 significantly reduced apoptotic cell death of synovial cells induced by the above chemicals. CONCLUSIONS: The protective effect of TGFbeta1 for mitochondrial homoeostasis may be important in the anti-apoptogenic function of TGFbeta1 for synovial cells.

New disease-modifying antirheumatic drug 2 acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid (KE-298) selectively augments activation-induced T cell death.

We examined in this study whether the newly developed disease-modifying antirheumatic drug (DMARD) 2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid (KE-298) augments activation-induced T cell death. Peripheral blood (PB) T cells, isolated from healthy donors, were activated by incubation with interleukin-2 (IL-2) followed by further culture with 12-0-tetradecanoyl phorbol 13-acetate (PMA) and ionomycin in the presence or absence of KE-298. The apoptosis of activated T cells was examined by flow cytometric determination of hypodiploid DNA. Fas expression and caspase-3 activity in activated T cells were also examined by flow cytometry, and expression of Fas ligand (FasL), Bcl-2-related proteins, and X chromosome-linked inhibitor of apoptosis protein (XIAP) was determined by Western blot analysis. Apoptosis was not obvious in resting T cells and was not augmented by KE-298. In contrast, apoptosis was clearly detected in activated T cells (activation-induced T cell death) with the increment of caspase-3 activity, and incubation of these cells with KE-298 further enhanced apoptosis. Treatment of activated T cells with KE-298 increased Bax expression but decreased XIAP expression without affecting the expression of Fas/FasL. Thus caspase-3 activity in activated T cells appeared to be increased by KE-298. Our results suggest that the newly developed DMARD, KE-298, selectively augmented activation-induced T cell death. This finding may contribute to the therapeutic efficacy of KE-298 in rheumatoid arthritis (RA) patients and provide new insight into the pharmacologic action of DMARDs.

Effects of nitric oxide on matrix metalloproteinase-2 production by rheumatoid synovial cells.

Nitric oxide (NO) is a multifunctional messenger molecule generated from L-arginine by a family of enzymes, including nitric oxide synthase (NOS). This study was performed to examine whether NO modulates the production of matrix metalloproteinases (MMPs), which degrade all components of extracellular matrix (ECM), in rheumatoid synovial cells. We investigated the effects of exogenously generated NO by a NO donor, S-nitroso-N-acetyl-DL-penicillamine (SNAP), on the MMPs production by rheumatoid synovial cells. Culture media conditioned by SNAP-treated synovial cells were examined by gelatin zymography and immunoblot analysis. Incubation of synovial cells with SNAP resulted in gelatinase A production in a dose-dependent fashion. Furthermore, RT-PCR analysis demonstrated that MMP-2 mRNA expression was induced in SNAP-treated synovial cells. In contrast, SNAP did not influence the production of TIMP-1 and TIMP-2, which preferentially inhibit MMP-2, by rheumatoid synovial cells. Our data indicate that NO could modulate MMP production by rheumatoid synovial cells and therefore contribute to ECM degradation of articular components in RA.

Evaluation of minimally invasive surgical staging for esophageal cancer.

BACKGROUND: Conventional imaging studies (computed tomography and endoscopic esophageal ultrasonography) used for preoperative evaluation of patients with esophageal cancer can be inaccurate for detection of small metastatic deposits. We evaluated the efficacy of minimally invasive surgical (MIS) staging as an additional modality for evaluation of patients with esophageal cancer. METHODS: Between December 1998 and February 2001, 33 patients with esophageal cancer were evaluated for surgical resection. Conventional imaging studies demonstrated operable disease in 31 patients and equivocal findings in 2 patients. All patients then underwent MIS staging (laparoscopy, bronchoscopy, and ultrasonography of the liver). We compared the results from surgical resection and MIS staging with those from conventional imaging. RESULTS: MIS staging altered the treatment plan in 12 (36%) of 33 patients; MIS staging upstaged 10 patients with operable disease and downstaged 2 patients with equivocal findings. MIS staging accurately determined resectability in 97% of patients compared with 61% of patients staged by conventional imaging. The specificity and negative predictive value for detection of unsuspected metastatic disease in MIS staging were 100% and 96%, respectively, compared with 91% and 65%, respectively, for conventional imaging studies. CONCLUSION: In addition to conventional imaging studies, MIS staging should be included routinely in the preoperative work-up of patients with esophageal cancer.

A system for computer-assisted design of stent-grafts for aortic aneurysms using 3-D morphological models.

A three-dimensional model was constructed from helical CT images for abdominal aortic aneurysm (AAA) and thoracic aortic aneurysm (TAA). A stent-graft was designed and positioned endoluminally on the computer. One hundred and nine stent-grafts for 101 patients were designed by this method and deployed well in all patients. The design time was reduced from 4 to 0.5 hr.

Effect of vitamin K2 on osteoblast apoptosis: vitamin K2 inhibits apoptotic cell death of human osteoblasts induced by Fas, proteasome inhibitor, etoposide, and staurosporine.

Vitamin K2 is used for the treatment of osteoporosis, but the precise mode of action is still not clear. We investigated the effects of vitamin K2 on apoptosis of human osteoblasts. Human osteoblastic cell line MG63 cells and human primary osteoblast-like cells obtained from bone fragments in corrective surgery were used as human osteoblasts. Cells were cultured with or without various concentrations of vitamin K2 and tumor necrosis factor-alpha (TNF-alpha). We then determined the proliferative response, expression of Fas and Bcl-2-related proteins, and Fas-mediated apoptosis of these cells induced by anti-Fas immunoglobulin M (IgM). In addition, the effect of vitamin K2 in osteoblast apoptosis induced by Z-Leu-Leu-Leu-aldehyde (LLL-CHO), etoposide, or staurosporine was also examined. Human osteoblasts did not show spontaneous apoptosis in culture, even in the presence of vitamin K2 or TNF-alpha. Furthermore, proliferation of the cells was not influenced by vitamin K2 or TNF-alpha. Fas was functionally expressed on human osteoblasts, and the treatment with TNF-alpha significantly enhanced both Fas expression and Fas-mediated apoptosis of osteoblasts. The addition of vitamin K2 to the culture resulted in a dose-dependent inhibition of functional Fas expression on osteoblasts, in the presence or absence of TNF-alpha. Treatment of human osteoblasts with vitamin K2 clearly suppressed Bax expression of the cells, although the expression of Bcl-2 was not influenced by vitamin K2. Fas ligand (FasL) cDNA transformants were cytotoxic against osteoblasts, and the cytotoxicity was increased when osteoblasts were treated with TNF-alpha. The addition of vitamin K2 to osteoblasts significantly decreased the cytotoxic effects of FasL cDNA transformants. Furthermore, apoptosis of human osteoblasts induced by LLL-CHO, etoposide, or staurosporine was also clearly suppressed in vitamin K2-treated osteoblasts. Our results suggest that vitamin K2 inhibits apoptotic cell death of osteoblasts and maintains the number of osteoblasts. These actions may explain the therapeutic efficacy of vitamin K2 in osteoporosis.

Detailed motion analysis of the left ventricular myocardium using an MR tagging method with a dense grid.

Detailed analysis of myocardial deformation through a whole cardiac cycle was accomplished using a tagging method with a high-density grid. Four sets of tagged images with a 4-mm-spacing grid were measured by generating four tagging pulses arranged at regular intervals in the cardiac cycle. Through each set of images, tag intersections were tracked semi-automatically. The estimated motions of tag intersections were concatenated so that sequential positions of myocardium were connected through a whole cardiac cycle. In vitro evaluation of the precision of this technique showed that the mean error of tracked 4-mm tag intersections was less than 0.47 +/- 0.17 mm, even on the quite low-contrast images, and the concatenation error caused by double concatenation was comparable to the interpolation error in the subendocardial area obtained with 8-mm tag intersection motion. The small difference between the two mean distance curves of the in vivo evaluation indicated that the method is useful for analyzing heart wall abnormalities. Magn Reson Med 44:73-82, 2000.

Nuclear factor-kappaB and caspases co-operatively regulate the activation and apoptosis of human macrophages.

Accumulating evidence suggests that macrophages function as major effector cells in the pathological process of various human diseases. We examined here the role of nuclear factor-kappaB (NF-kappaB) and caspases in the regulation of activation and apoptosis of macrophages. Activation of the human monoblastic leukaemia cell line, U937, by phorbol 12-myristate 13-acetate (PMA) increased the expression of CD14/CD86, and cytokine production. PMA stimulation also increased the expression of both pro-caspase-8 and pro-caspase-3 in U937, but not apoptosis or intracellular caspase-3 activity. PMA also increased the expression of X-chromosome-linked inhibitor of apoptosis protein (XIAP) in U937, suggesting an inhibitory action for XIAP on the caspase cascade in PMA-stimulated U937. Electrophoretic mobility shift assay (EMSA) showed a significant increase of nuclear NF-kappaB activity in PMA-stimulated U937. When a potent NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC), was added to U937 cell culture in the presence of PMA, apoptosis was triggered by activation of caspase-3, which was induced by caspase-8 activation. XIAP expression was markedly suppressed in PMA-treated U937 in the presence of PDTC. The inhibitors of caspase-8 and caspase-3 mostly inhibited apoptosis of U937 treated with PMA in the presence of PDTC. Furthermore, a phenotype of U937 treated with PMA and PDTC in the presence of caspase inhibitor was almost identical to that of unstimulated U937. Our results suggest that the signalling pathways involved in the activation and apoptosis of human macrophages could be co-operatively regulated by the use of NF-kappaB and caspase inhibitors, thus enabling the control of macrophage function and number.

CD4+ T cell-mediated cytotoxicity toward thyrocytes: the importance of Fas/Fas ligand interaction inducing apoptosis of thyrocytes and the inhibitory effect of thyroid-stimulating hormone.

The accumulation of activated CD4+ T cells and antigen (Ag)-dependent cellular interactions between thyrocytes and CD4+ T cells have been determined in thyroid gland from patients with Graves' disease. The Fas/Fas ligand (FasL) interaction between antigen-presenting cells and T cells regulates the apoptosis of the former cells triggered by the latter cells. The inhibition of Fas-mediated apoptosis in thyrocytes could be a underlying mechanism of hyperplasia of thyrocytes in patients with Graves' disease. We investigated the potential role of Fas/FasL interaction between thyrocytes and CD4+ T cells in the induction of Fas-mediated apoptosis of the former cells induced by the latter cells. The presence of only a few specific T cells responsive to a putative autoantigen has hampered the investigation of specific T cell activation toward antigen-presenting cells (APCs). Therefore, we used a superantigen, staphylococcal enterotoxin B (SEB), to examine specific T cell activation toward thyrocytes in vitro since it stimulates a large proportion of T cells with particular Vbeta elements. Spontaneous apoptosis of thyrocytes in culture was not found even in the presence of various kinds of cytokines. In contrast, a clear induction of Fas-mediated apoptosis by anti-Fas IgM was determined in interferon-gamma (IFN-gamma)-stimulated thyrocytes. In addition, a significant cytotoxicity of purified CD4+ T cells toward IFN-gamma-stimulated thyrocytes in the presence of SEB was induced, and the addition of anti-HLA-DR and -DQ monoclonal antibodies (mAbs) or blockade of the Fas/FasL interaction reduced this cytotoxicity. FasL expression of CD4+ T cells cocultured with IFN-gamma-stimulated thyrocytes in the presence of SEB was clearly induced. Furthermore, the addition of mAbs against CD54 and CD58 inhibited both cytotoxicity and FasL expression of CD4+ T cells. The cytotoxicity of CD4+ T cells toward IFN-gamma-stimulated, SEB-pulsed thyrocytes was markedly inhibited when we used thyrocytes cultured with IFN-gamma in the presence of thyroid-stimulating hormone (TSH) as target cells. Our results suggest that 1) CD4+ T cells were activated by thyrocytes expressing MHC class II molecules in an SEB-dependent manner and then expressed FasL. 2) These activated FasL+ CD4+ T cells killed thyrocytes by interacting with Fas on thyrocytes and FasL on activated CD4+ T cells. The presence of costimulating molecules such as CD54 and CD58 on thyrocytes was also necessary to generate activated FasL+ CD4+ T cells. 3) Since the actions of thyroid stimulating antibody (TSAb) toward thyrocytes are similar to those of TSH, one goitrogenic activity of TSAb may, in part, be due to the inhibitory effect on Fas-mediated apoptosis of thyrocytes triggered by activated CD4+ T cells.

FK506 augments glucocorticoid-mediated cyclooxygenase-2 down-regulation in human rheumatoid synovial fibroblasts.

Prostaglandins (PG) formed by cyclooxygenase (COX) enzymes are important mediators of inflammation in rheumatoid arthritis. The contribution of the inducible COX-2 to inflammation in the rheumatoid synovium is well documented. We examined the regulation of COX-2 mRNA and protein expression in response to both glucocorticoids (GC) and FK506 using rheumatoid synovial fibroblasts. Combined treatment of FK506 and a low concentration of dexamethasone (DEX) (10(-9) M) down-regulated synovial COX-2 mRNA and protein expression. In contrast, neither FK506 nor DEX (10(-9) M) alone influenced COX-2 expression. Immunocytochemical studies showed that pretreatment with FK506 enhanced the nuclear translocation of the glucocorticoid receptor (GR) in synovial fibroblasts in the presence of low concentrations of DEX (10(-9) M). Transient transfection experiments showed that treatment of cells with FK506 enhanced the expression of glucocorticoid-responsive gene reporter in the presence of DEX (10(-9) M). NF-kappaB is known to mediate the transcriptional activation of the COX-2 gene. Electrophoretic mobility shift assay demonstrated that DNA-binding activity of NF-KB was suppressed more profoundly by FK506 plus DEX (10(-9) M) treatment with those of DEX (10(-9)M) alone in IL-1beta-stimulated synovial cells. Our results indicated that FK506-induced potentiation of GR-mediated repression of synovial COX-2 gene transcription is the result of increased translocation of GR to the nucleus and subsequent repression of NF-kappaB transactivation. Our results also suggest that FK506 may exert anti-inflammatory effects in the rheumatoid synovium by potentiating GR-mediated signal transduction.

Induction of COX-2 expression by nitric oxide in rheumatoid synovial cells.

Prostaglandins formed by cyclooxygenase (COX) enzymes are important mediators of inflammation. The contribution of inducible COX-2 in the rheumatoid synovium is well documented. In this study, we evaluated the contribution of nitric oxide (NO) to COX-2 expression in rheumatoid synovial cells. Exposure of rheumatoid synovial cells to a NO donor, SNAP, induced COX-2 protein expression in a dose-dependent manner. RT-PCR analysis also demonstrated that COX-2 mRNA was induced in SNAP-treated synovial cells. Dexamethasone at therapeutic concentrations markedly inhibited this NO-mediated COX-2 expression in synovial cells. In contrast to its effect on COX-2 expression, SNAP did not affect the constitutive expression of COX-1 in rheumatoid synovial cells. Our findings suggest that NO is an important modulator of COX-2 expression and that glucocorticoids exert their anti-inflammatory action in rheumatoid synovium, at least in part, by suppression of COX-2 induction.