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.

Dexamethasone protection of rat intestinal epithelial cells against oxidant injury is mediated by induction of heat shock protein 72.

Although the therapeutic actions of glucocorticoids are largely attributed to their anti-inflammatory and immunosuppressive effects, they have been implicated in enhancing tissue and cellular protection. In this study, we demonstrate that dexamethasone significantly enhances viability of IEC-18 rat small intestinal cells against oxidant-induced stress in a dose-dependent fashion. This protective action is mediated by induction of hsp72, the major inducible heat shock protein in intestinal epithelial cells. Dexamethasone stimulates a time- and dose-dependent response in hsp72 protein expression that parallels its effects on cell viability. Furthermore, the induction of hsp72 is tissue dependent, as nonintestinal epithelioid HeLa cells show differential induction of hsp72 expression in response to the same dexamethasone treatment. Antisense hsp72 cDNA transfection of IEC-18 cells abolishes the dexamethasone-induced hsp72 response, without significantly affecting constitutive expression of its homologue, hsc73. Dexamethasone treatment also significantly induces hsp72 protein expression in rat intestinal mucosal cells in vivo. These data demonstrate that glucocorticoids protect intestinal epithelial cells against oxidant-induced stress by inducing hsp72.

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.

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.

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.

Fas and Fas ligand interaction is necessary for human osteoblast apoptosis.

We investigated the cellular and humoral interactions between peripheral blood mononuclear cells (PBMCs) and human osteoblasts, leading to apoptosis of osteoblasts. Human osteoblastic cell line MG63 and human primary osteoblast-like cells obtained from biopsy specimens were used in this study. PBMCs were isolated from healthy donors and cultured with or without stimulation by recombinant interleukin-2 followed by 12-o-tetradecanoylphorbol 13-acetate with ionomycin. Fas was functionally expressed on MG63 and primary osteoblast-like cells. Activated PBMCs expressed Fas ligand (FasL) strongly on their surface and killed MG63 and primary osteoblast-like cells. Cultured supernatants of activated PBMCs also induced apoptotic cell death of MG63 and primary osteoblast-like cells. In contrast, both unstimulated PBMCs and cultured supernatants of unstimulated PBMCs did not induce apoptosis of these cells. Furthermore, the cytotoxic effect and induction of apoptosis against MG63 and primary osteoblast-like cells by activated PBMCs and cultured supernatants were inhibited significantly by human Fas chimeric protein. Our data showed that human osteoblasts expressed Fas fuctionally and both membrane-type and soluble form FasL from activated PBMCs induced apoptosis of these cells, providing the one possible mechanism of bone loss in inflammatory diseases such as rheumatoid arthritis.

Night blindness secondary to vitamin A deficiency in a patient with bile duct strictures after liver transplantation.

Vitamin A deficiency and resulting night blindness have previously been reported in patients with chronic liver disease before undergoing liver transplantation. Because early identification of patients with vitamin A deficiency can lead to the relief of symptoms and the prevention of irreversible retinal degeneration, vitamin A deficiency should always be considered in the differential diagnosis of visual disturbances in patients with liver disease. We describe a case of night blindness due to vitamin A deficiency resulting from bile duct strictures in a post-orthotopic liver transplant patient and its successful resolution with vitamin A supplementation.

Mechanisms and treatment of diarrhea in inflammatory bowel diseases.

: Diarrhea is one of the most common symptoms of patients with inflammatory bowel disease (IBD), having a reported frequency of 66-92% (1). Its frequency, severity, and metabolic effects are dependent on the degree, location, and extent of intestinal inflammation. Its presence and severity in IBD patients have served as useful indicators of disease activity and therapeutic response. To date, there are few specific treatments of IBD-associated diarrhea, in part because of the complexity and limited understanding of mechanisms. Physicians have largely resorted to treatments aimed at symptomatic control of diarrhea or at reducing the underlying inflammatory and immune processes. Unfortunately, many IBD patients, particularly those with severe disease, find the diarrhea especially debilitating and unpleasant, significantly affecting lifestyle and quality of life.In this review, we attempt to summarize the current understanding of causes of inflammation-associated diarrhea. Much of this information is derived from studies of experimental models of colitis and diarrhea and from in vitro models of established intestinal cell lines where specific pathophysiological processes can be studied. Thus, the relative importance of many of these potential diarrheal mechanisms in IBD cannot be presently ascertained and await additional studies in this area. However, some liberty has been taken to distill this information to create a conceptual framework for explaining how diarrhea develops in patients with inflammatory bowel diseases and how it can be treated.

An attempt to add biological functions by genetic engineering in order to produce high-performance bioreactor cells for hybrid artificial liver: transfection of glutamine synthetase into Chinese hamster ovary (CHO) cell.

In the course of immortalization, hepatocyte cell lines lose their original differentiated functions, such as ammonia removal and urea formation, drug metabolism, serum protein synthesis, etc. (Enosawa et al., Cell Transplant. 5:S39-S40; 1996). With the aim of adding lost or deficient functions and producing cell lines for the bioreactor of a hybrid artificial liver, rat glutamine synthetase (GS) gene was transfected into Chinese hamster ovary (CHO) cells, because it is able to lower the ammonia level. The GS gene-inserted pSV2 plasmid was transfected into the CHO-K1 line by electroporation. Transfected CHO (GS-CHO) cells were cultured in a glutamine-free medium containing ammonia, glutamic acid, and the GS inhibitor methionine sulfoximine (MSX). The MSX concentration was increased stepwise from 25 mumol/L to 1600 mumol/L to amplify the GS gene. In several GS-CHO sublines resistant to 300-1600 mumol/L of MSX, the specific activities of GS were increased from 0.2 x 10(4) to 1.7-2.9 x 10(4) unit/10(6) cells. When the amplified GS-CHO cells were cultured in the ammonia-containing medium, a slow but steady decrease of the ammonia level was observed when the level was high. Finally, the prospect of genetically modulated cells for bioreactors in the hybrid artificial liver is discussed.

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.

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.

[Histological and ultrastructural study of degeneration of the lumbar intervertebral disc in the rabbit following nucleotomy, with special reference to the topographical distribution pattern of the degeneration].

The degenerative and repair processes of rabbit lumbar disc after nucleotomy were topographically followed by light and electron microscopy. Light microscopic studies showed a proliferation of cells with large pericellular matrices in the inner annulus. Electron microscopic changes of the inner annular cells showed an increase in the number of micropinocytotic vesicles in the first 8 weeks following nucleotomy, early appearance of lysosomes, and a reduction in the amount of rough endoplasmic reticula from 6 weeks after operation. 'Islet areas' consisting of small ruthenium red positive materials increased in number in the pericellular matrices. These changes were topographically similar to each of them. Activation of remnant notochordal cells was evident morphologically and autoradiographically. It seemed most likely that cells of the inner annulus were activated for a initial certain period following nucleotomy, while they degenerated rapidly after surgery. Light microscopy showed these changes of annular tissue following nucleotomy to be just like those after disc incision.

Evaluation of per-procedure equipment costs in an outpatient endoscopy center.

BACKGROUND: As disposable endoscopes become available, we need baseline costs associated with reusable instruments to make financially intelligent choices. Accordingly, we analyzed the per-use cost of several types of gastrointestinal endoscopes at our institution. METHODS: Records of 44 gastrointestinal endoscopes were analyzed. Data defined included purchase price, repair and cleaning expense (labor and materials), and number of uses. The labor cost per-use associated with endoscope cleaning was estimated by taking an average time required to clean an endoscope multiplied by the technician's salary. RESULTS: The average number of years of endoscope use varied from 4.6 to 6.9 years contingent on the type of endoscope. For flexible sigmoidoscopes, the average total cost per use was $8.35, and for colonoscopes the cost was $21.81. For gastroscopes and diagnostic and therapeutic duodenoscopes, costs were $20.99, $49.15, and $45.16, respectively. CONCLUSIONS: (1) Excluding costs associated with the procedure itself (admit-recovery, drugs, disposable equipment, and procedural personnel), total peruse scope cost ranged from a low of $8.35 for the flexible sigmoidoscope to $49.15 for the diagnostic duodenoscope. (2) The most important variables associated with per-use endoscope cost included number of uses, initial purchase price, and repair costs. (3) Techniques such as the above can be used to define per-procedure costs for a particular practitioner or institution.

Presentation and treatment of annular pancreas in an adult population.

OBJECTIVE: To describe a series of adult patients with annular pancreas, their presentation, and treatment modalities. METHOD: A retrospective chart review of patients seen at a multispecialty referral center from 1977 to 1994. RESULTS: Seven adult patients (ages ranging from 33 to 77 yr, four females and three males) presented with various symptoms and signs: abdominal pain (six patients) gastric outlet obstruction (two), pancreatitis (two), pancreatic mass (two), gastric/duodenal ulcer (one), and/or postoperative obstructive jaundice (one). The duration of symptoms ranged from 1 wk to 16 yr before diagnosis (median 18 months). Upper GI radiography was consistent with annular pancreas in two cases, CT scan in two cases (neither of which actually depicted the annulus), and four of six successful endoscopic retrograde cholangiopancreatographies. Three patients were diagnosed during operative procedures. Five of the seven patients required therapeutic operative procedures that included transduodenal sphincteroplasty, duodenojejunostomy, gastrojejunostomy, subtotal gastrectomy, or Whipple procedure. Four of the five had significant symptomatic relief. In one case, endoscopic sphincterotomy and biliary stent placement was therapeutic. CONCLUSIONS: 1) Annular pancreas occasionally presents in the adult population. 2) Although gastric outlet obstruction was seen in two of seven patients, a plethora of additional presentations included pancreatic mass, pancreatitis, peptic ulcer disease, and post-operative obstructive jaundice. 3) Diagnosis of annular pancreas was most commonly suggested by upper GI series or endoscopic retrograde cholangiopancreatography. However, fully 40% of diagnoses required surgery for confirmation. 4) In contrast to the pediatric population in whom gastrojejunostomy or duodenojejunostomy is the treatment of choice, a variety of surgical as well as interventional endoscopic procedures were utilized for effective treatment in adults with annular pancreas.

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.