Wnt11 overexpression promote adipose-derived stem cells differentiating to the nucleus pulposus-like phenotype.

OBJECTIVE: Our present study aimed to evaluate the effects of Wnt11 overexpression on the adipose-derived stem (ADSCs) cells differentiation to the nucleus pulposus (NP) cells and its function in the ADSCs cells growth, proliferation and induction of the NP cells markers. MATERIALS AND METHODS: The cell growth was detected using the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) (MTT) assay and the cell cycle was assessed by the flow cytometry. The cells morphology was evaluated using the transmission electron microscopy. The transfection efficiencies of Wnt11 lentivirus were observed under fluorescence microscope. Besides, Quantitative Real-time PCR and Western blot analysis were applied to detect the relative mRNA and protein levels. RESULTS: Wnt11 lentivirus treatment could inhibit the ADSCs cells growth and arrest the cell cycle progression at the G0/G1 phase. Besides, the overexpression of Wnt11in ADSCs cells could induce the expression of the NP cells markers. Levels of SOX-9, aggrecan, and collagen type II were significantly increased in the ADSCs cells transfected with the Wnt11 lentivirus, in comparison with the untreated cells or the vector controls. CONCLUSIONS: The Wnt11 overexpression may provide some experimental evidence for the possible opportunity of the Wnt11 to promote the ADSCs cells differentiating to the NP cells. Therefore, the Wnt11 overexpression may have a potential utility for the treatment of the intervertebral disc degeneration.

Osteomyelitis of the pelvis/hips in paralyzed patients: accuracy and clinical utility of MRI.

PURPOSE: The goal of our study was to determine the accuracy and clinical utility of MRI in the diagnosis of osteomyelitis of the pelvis/hips in paralyzed patients. METHOD: In 44 paralyzed patients, 59 consecutive MR examinations of the pelvis/hips were evaluated prospectively. Criteria for diagnosis of osteomyelitis were based on those established in previous studies of complex, nonhematogenous osteomyelitis (diabetic foot). Average follow-up was 3 years. The standard of reference for the diagnosis of osteomyelitis was histologic/microbiologic results of surgical biopsy specimens or clinical follow-up. Note was made if decubitus ulcers, sinus tract, fistula, fluid collection, abscess, septic arthritis, joint effusion, bursitis, or heterotopic ossification was present on MRI. Comparison of the extent of infection by MRI and surgical margins was performed. Effect on surgical treatment was defined by absence of recurrent infection at the surgical site within 6 weeks of limited resection. RESULTS: The criteria for diagnosis of osteomyelitis were fulfilled in 49 of 57 MR studies for an overall accuracy of 97%. There was one false-negative MR study. MRI for the diagnosis of osteomyelitis yielded a sensitivity of 98% and a specificity of 89%. There were 41 decubitus ulcers, 28 sinus tracts, 2 fistulae, 14 fluid collections, 15 abscesses, 9 hips with septic arthritis, 10 "bland" hip effusions, 5 cases of trochanteric bursitis, and 30 patients with heterotopic ossification. Twenty-one patients underwent limited surgical resection guided by MR findings in which only the enhancing area was resected. There was only one recurrence of osteomyelitis at the surgical margins. CONCLUSION: MRI is accurate in the diagnosis of osteomyelitis and associated soft tissue abnormalities in spinal cord-injured patients. MRI can delineate the extent of infection in guiding limited surgical resection and preserving viable tissue.

Papillary projections in ovarian neoplasms: appearance on MRI.

Papillary projections are distinctive pathologic features of epithelial ovarian neoplasms. We sought to determine whether these structures have recognizable features on MRI. A search of a database of 125 patients on whom MRI was performed with pelvic phased-array coil and abdominal surgical exploration was performed for suspected gynecologic disease identified 15 patients who had either MRI reports or pathology reports mentioning papillary projections in an adnexal mass. The MR images were reviewed to characterize the size, structure, and signal intensity of papillary projections. Pathologic correlation was performed on these and on four surgical specimens imaged with high resolution technique. Pathologic correlation showed that larger papillary projections had a distinctive structure of a fibrous stalk supporting clumps of edematous papillae with signal intensity similar to that of fluid on T2-weighted images. Smaller papillae showed nondescript intracystic projections of intermediate signal intensity on T2-weighted images. All papillary projections in vivo enhanced after injection of gadopentetate dimeglumine. Papillary projections have an appearance on MRI that reflects their histologic structure.

The cessation of fluoridated water administration and the fluoride distribution profiles in rat molar cementum.

The aim of this work was to obtain further information about the origin of fluoride profiles in cementum. Fluoride was administered to rats at varying doses (0.50, 100 ppm F in drinking water) and for different durations (4, 13 and 25 weeks). Fluoride distribution across the full thickness of molar cementum in rats was measured by means of an abrasive micro-sampling technique. The average fluoride concentrations in cementum increased significantly with increasing dose and duration of fluoride administration. The relative reduction of the average fluoride concentrations after cessation of fluoride administration was 94.2-36.5% at 50 ppm F and 62.2-49.2% at 100 ppm F in the outer layers (1-60 microns) and 91.5-24.1% at 50 ppm F and 74.1-7.6% at 100 ppm F in the middle (61-120 microns) layers of the cementum, respectively. The reduction rates were more closely related to the time intervals following cessation rather than fluoride concentrations in drinking water or specificity within the cementum. Two factors which may influence this are new cementum formation after withdrawal of fluoride and some fluoride release from cementum surfaces when the fluoride supply stopped. It was concluded that the cessation of fluoride administration reduced the fluoride concentration on the outer layers of cementum differing from bone where reduction occurs across the entire thickness.

Adrenal masses: correlation between CT attenuation value and chemical shift ratio at MR imaging with in-phase and opposed-phase sequences.

PURPOSE: To correlate attenuation values at computed tomography (CT) with signal intensity at chemical-shift magnetic resonance (MR) imaging in adrenal masses. MATERIALS AND METHODS: Thirty-eight patients with 47 adrenal lesions underwent MR imaging and unenhanced CT examinations. MR examinations, performed at 1.5 T, included T1-weighted imaging with fat and water in phase and gradient-echo imaging with fat and water out of phase (repetition time, 45-180 msec; echo time, 1.4-3.1 msec). Lesion-to-spleen signal intensity ratios were calculated for the in-phase and opposed-phase images. The chemical-shift ratio, a measure of signal intensity loss between in-phase and opposed-phase images, and the CT attenuation value (in Hounsfield units) were determined for each lesion. RESULTS: A statistically significant correlation (0.85) was found between attenuation and chemical-shift-ratio values (P < .000001). Attenuation in six benign lesions was within 2 standard deviations of the mean attenuation in malignant lesions, and the chemical-shift ratio in eight benign lesions was within 2 standard deviations of the mean chemical-shift ratio in malignant lesions. Six of these eight lesions were misclassified on the basis of both attenuation and chemical-shift-ratio values. CONCLUSION: CT attenuation values are highly correlated with chemical-shift ratios. Both values were indeterminate for a similar subset of benign lesions.

Prospective evaluation of lesions of the mandible and maxilla: findings on multiplanar and three-dimensional CT.

The treatment of benign and malignant oropharyngeal diseases is greatly influenced by the degree of invasion of the mandible and maxilla. 3D DEN (Columbia Scientific, Inc., Columbia, MD) is a computer software program that reassembles data from a series of axial CT scans into cross-sectional oblique, three-dimensional, and panoramic CT reformations. Multiplanar reformatted CT overcomes many of the problems associated with conventional axial and coronal CT. True cross-sectional and panoramic images are obtained. The contour, height, thickness, and mineralization of the entire alveolar bone along the curvature of the jaw are precisely defined. Also, the course of the inferior alveolar nerve, anatomic features of the incisive canal, and evaluation of the maxillary sinus can be assessed with this technique. This technique was originally developed to evaluate dental implants [1-3]. Other software programs are commercially available that do similar reconstructions. The purpose of this pictorial essay is to illustrate the findings on multiplanar reformatted and three-dimensional CT in the preoperative evaluation of mandibular and maxillary abnormalities.

Sonographic demonstration of calculi within a urethral diverticulum.

A case in which sonography demonstrated that calculi may arise in female urethral diverticula is presented. The diagnosis of female urethral diverticula is reviewed.

Salpingoureteral fistula: CT appearance.

Laparoscopic laser surgery is becoming increasingly common as treatment for endometriosis. We report a case of computed tomographic (CT) demonstration of salpingoureteral fistula secondary to laparoscopic laser surgery.

Mycobacterial disease associated with aplastic anaemia.

Haematological changes associated with infectious disease are relatively common but true aplastic anaemia secondary to infection is rare. We describe a patient wit disseminated Mycobacterium avium-intracellulare infection and who had a histologically proven remission of his aplastic anemia accompanying antimycobacterial therapy. We also review the literature on the haematological changes associated with mycobacterial infections and other infectious causes of aplastic anaemia.

Effects of pH on tubulin-nucleotide interactions.

Significant GTP-independent, temperature-dependent turbidity development occurs with purified tubulin stored in the absence of unbound nucleotide, and this can be minimized with a higher reaction pH. Since microtubule assembly is optimal at lower pH values, we examined pH effects on tubulin-nucleotide interactions. While the lowest concentration of GTP required for assembly changed little, GDP was more inhibitory at higher pH values. The amounts of exogenous GTP bound to tubulin at all pH values were similar, but the amounts of exogenous GDP bound and endogenous GDP (i.e., GDP originally bound in the exchangeable site) retained by tubulin rose as reaction pH increased. Endogenous GDP was more efficiently displaced by exogenous GTP than GDP at all pH values, but displacement by GTP was 10-15% greater at pH 6 than at pH 7. Dissociation constants for GDP and GTP were about 1.0 microM at pH 6 and 0.02 microM at pH 7. A small increase in the affinity of GDP relative to that of GTP occurs at pH 7 as compared to pH 6, together with a 50-fold absolute increase in the affinity of both nucleotides for tubulin at pH 7. The time courses of microtubule assembly and GTP hydrolysis were compared at pH 6 and pH 7. At pH 6, the two reactions were simultaneous in onset and initially stoichiometric. At pH 7, although the reactions began simultaneously, hydrolysis seemed to lag substantially behind assembly. Unhydrolyzed radiolabeled GTP was not incorporated into microtubules, however, indicating that GTP hydrolysis is actually closely coupled to assembly. The apparent lag in hydrolysis probably results from a methodological artifact rather than incorporation of GTP into the microtubule with delayed hydrolysis.

Differential effects of magnesium on tubulin-nucleotide interactions.

Magnesium-depleted 2-(N-morpholino)ethanesulfonate (Mes), glutamate, tubulin and microtubule-associated proteins were prepared and used to study the effects of exogenously added MgCl2 on tubulin-nucleotide interactions in 0.1 M Mes with microtubule-associated proteins and in 1.0 M glutamate. Endogenous levels of Mg2+ in the systems studied were approximately stoichiometric with the tubulin concentrations and largely derived from the tubulin. We examined the effects of added Mg2+ on tubulin polymerization, GDP inhibition of polymerization, binding of GDP and GTP to tubulin, and GTP hydrolysis. Exogenously added Mg2+ had markedly different effects on these reactions. The order of their sensitivity for a requirement for added Mg2+ was as follows: GTP binding greater than GTP hydrolysis greater than polymerization greater than GDP binding. Inhibition of polymerization by GDP varied inversely with the Mg2+ concentration and was greatest in the absence of the cation. These results indicate that GDP and GDP-Mg2+ interact with similar affinity at the exchangeable site, while GTP-Mg2+ has a higher affinity for tubulin than does free GTP. Nevertheless, under appropriate conditions, free GTP can interact sufficiently well with tubulin to permit both nucleation and elongation reactions.

Maytansine inhibits nucleotide binding at the exchangeable site of tubulin.

The antineoplastic drug maytansine inhibits the binding of exogenously added radiolabeled GDP and GTP to tubulin (50% inhibition at 9-10 microM drug at 0 degrees). Vinblastine was 1/10-th as inhibitory. Neither maytansine nor vinblastine displaced GDP from tubulin, and both drugs virtually eliminated dissociation of radiolabeled GDP from the exchangeable site. Maytansine also inhibits binding of nucleotides to a vacant exchangeable site. Maytansine thus prevents nucleotide exit and entry at the exchangeable site because of a direct physical obstruction or a conformational change in the tubulin molecule.