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Harmonic imaging techniques have been applied in ultrasonic elasticity imaging to obtain higher-quality tissue motion tracking data. However, harmonic tracking can be signal-to-noise ratio and penetration depth limited during clinical imaging, resulting in decreased yield of successful shear wave speed measurements. A logical approach is to increase the source pressure, but the in situ pressures used in diagnostic ultrasound have been subject to a de facto upper limit based on the Food and Drug Administration guideline for the mechanical index (MI <1.9). A recent American Institute of Ultrasound in Medicine report concluded that an in situ MI up to 4.0 could be warranted without concern for increased risk of cavitation in non-fetal tissues without gas bodies if there were a concurrent clinical benefit. This work evaluates the impact of using an elevated MI in harmonic motion tracking for hepatic shear wave elasticity imaging. The studies indicate that high-MI harmonic tracking increased shear wave speed estimation yield by 27% at a focal depth of 5 cm, with larger yield increase in more difficult-to-image patients. High-MI tracking improved harmonic tracking data quality by increasing the signal-to-noise ratio and decreasing jitter in the tissue motion data. We conclude that there is clinical benefit to use of elevated acoustic output in shear wave tracking, particularly in difficult-to-image patients., (Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.)

Tissue harmonic imaging has been widely used in abdominal imaging because of its significant reduction in acoustic noise compared with fundamental imaging. However, tissue harmonic imaging can be limited by both signal-to-noise ratio and penetration depth during clinical imaging, resulting in decreased diagnostic utility. A logical approach would be to increase the source pressure, but the in situ pressures used in diagnostic ultrasound are subject to a de facto upper limit based on the U.S. Food and Drug Administration guideline for the mechanical index (<1.9). A recent American Institute of Ultrasound in Medicine report concluded that an effective mechanical index ≤4.0 could be warranted without concern for increased risk of cavitation in non-fetal tissues without gas bodies, but would only be justified if there were a concurrent improvement in image quality and diagnostic utility. This work evaluates image quality differences between normal and elevated acoustic output hepatic harmonic imaging using a transmit frequency of 1.8 MHz. The results indicate that harmonic imaging using elevated acoustic output leads to modest improvements (3%-7%) in contrast-to-noise ratio of hypo-echoic hepatic vessels and increases in imaging penetration depth on the order of 4 mm per mechanical index increase of 0.1 for a given focal depth. Difficult-to-image patients who suffer from poor ultrasound image quality exhibited larger improvements than easy-to-image study participants., (Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the diagnostic performance of MDCT in the diagnosis of closed loop small bowel obstruction., Materials and Methods: One hundred fifty patients with CT reports including "small bowel obstruction (SBO)" between 1/30/2011 and 12/4/2012 were included (65 men, 85 women, mean age 63 years). CT examinations were independently and blindly reviewed by five radiologists to determine the presence of closed loop obstruction (CL-SBO) and to assess findings of bowel ischemia. Clinical records were reviewed to determine management and operative findings. Using operative findings as a gold standard, reader agreement for the diagnosis of and the CT findings associated with CLO was analyzed using Pearson's correlation (r). Positive predictive value (PPV) and negative predictive value for the diagnosis of CL-SBO and CT signs of bowel ischemia were analyzed., Results: Eighty-eight of 150 patients underwent operative intervention for SBO and 24/88 were considered CL-SBO operatively. Average reader sensitivity and specificity for CL-SBO was 53 % (95 % CI 44-63 %) and 83 % (95 % CI 79-87 %). Reader agreement on CL-SBO was poor to moderate (K = 0.39-0.63). Reader agreement for CT signs of bowel ischemia resulting in a diagnosis of CL-SBO was weak (r = 0.19-0.32)., Conclusion: The CT diagnosis of CL-SBO is complex and associated imaging findings have variable sensitivity for predicting a closed loop operative diagnosis. CT can be helpful in excluding a closed loop component in patients with SBO.

Objective: The objective of our study was to test the hypothesis that an intercostal approach to imaging-guided percutaneous subdiaphragmatic abscess drainage is as safe as a subcostal approach., Materials and Methods: A cohort of 258 consecutive patients with one or more subdiaphragmatic abscesses referred for imaging-guided (CT or ultrasound) percutaneous drainage was identified. Demographic characteristics and clinical outcomes were compared between patients who underwent drainage catheter placement via an intercostal approach versus those who underwent drainage catheter placement via a subcostal approach., Results: Percutaneous drainage was performed for 441 abscesses in 258 patients in 409 separate procedures (214 via an intercostal approach, 186 by a subcostal approach, and nine by a combined approach). The total number of pleural complications was significantly higher in the intercostal group (56/214 [26.2%]) than the subcostal group (15/186 [8.1%]; p < 0.001). These complications included a significantly higher pneumothorax rate in the intercostal group than the subcostal group (15/214 [7.0%] vs 0/186 [0%], respectively; p < 0.01) and a higher incidence of new or increased pleural effusions (38/214 [17.8%] vs 14/186 [7.5%]; p < 0.01). The incidence of empyema was low and similar between the two groups (intercostal vs subcostal, 3/214 [1.4%] vs 1/186 [0.5%]; p = 0.63). A few of the complications in the patients who underwent an intercostal-approach drainage were clinically significant. Four of the 15 pneumothoraces required thoracostomy tubes and eight of 38 (21.1%) pleural effusions required thoracentesis, none of which was considered infected., Conclusion: An intercostal approach for imaging-guided percutaneous drainage is associated with a higher risk of pleural complications; however, most of these complications are minor and should not preclude use of the intercostal approach.

Objectives: To investigate the ability of staging computed tomography (CT) without bowel preparation to accurately localize colonic tumors compared to optical colonoscopy., Methods: The local institutional review board approved this retrospective and HIPAA-compliant study. Forty-six patients with colonic adenocarcinoma, preoperative colonoscopy, and staging CT within 60 days of resection were included. Patients underwent contrast enhanced CT imaging without bowel preparation or oral contrast. The colon was divided into four segments with the operative reports used as the standard. Rectal and cecal cancers were excluded. CT scans were reviewed by 5 readers in a segmental binary fashion using a 5-point confidence scale in two sessions blinded and unblinded to the colonoscopy report., Results: At surgery 49 tumors were found in 46 patients. Readers detected 86.1%, 74.3%, and 66.9% of lesions with 92.0%, 94.1%, and 95.4% accuracy for confidence scores of ≥ 3, ≥ 4, and 5. CT interobserver agreement was good (κ=0.82) for the unblinded and moderate (κ=0.60) for the blinded read. Colonoscopic localization was only 78.7% accurate with 2 tumors undiscovered. Colonoscopic accuracy was low in the descending colon (57.1%) and the transverse colon (55.6%)., Conclusions: Preoperative staging CT is more accurate than colonoscopy in the localization of colonic tumors., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Luteoma of pregnancy is a rare, tumorlike ovarian mass that develops during pregnancy and regresses after delivery. Generally, these masses are discovered incidentally during cesarean delivery or tubal ligation. Some of these patients will develop hirsutism or virilization during late pregnancy with or without fetal masculinization due to circulating androgens. The imaging features of this entity have been only rarely reported. An incidentally discovered luteoma of pregnancy in a 23-year-old patient during routine obstetric ultrasound is described and the image features in ultrasound and magnetic resonance (MR) imaging are discussed and compared with other studies. The patient underwent surgery to extract this mass considering the imaging findings were suspicious for neoplasia and the size and location could have potentially caused dystocia. This type of mass can mimic ovarian neoplasia and a correlation with imaging and laboratory findings can avoid an unnecessary surgical procedure during pregnancy., (Copyright (c) 2009 Wiley-Liss, Inc.)

This HIPAA-compliant study had institutional review board approval, with waiver of informed consent. The purpose was to test the hypothesis that, compared with a standard magnetic resonance (MR) cholangiography sequence, MR cholangiography with a sampling perfection with application optimized contrasts using different flip angle evolutions (SPACE) sequence reduces ghosting artifacts while maintaining image quality and sufficient contrast-to-noise ratio (CNR) at 3.0 T. The study population consisted of 15 women and 14 men (mean age, 47.2 years +/- 18.1 [standard deviation]) who were consecutively referred for MR cholangiography between November 2004 and November 2005. Acquisition times were lower and N/2 ghosting artifacts were eliminated with SPACE. However, the SPACE sequence yielded images that were visually grainier and had lower CNR. Overall, the readers preferred the appearance of images obtained with the SPACE sequence, most likely because of the elimination of N/2 ghosting artifacts., ((c) RSNA, 2008.)

Objective: Glenoid dysplasia is known to predispose affected patients to accelerated degenerative joint disease. We have observed that there is often an association between glenoid dysplasia and posterior labral tears. Our goal was to assess glenoid dysplasia as seen on MRI and to assess its association with posterior labral tears., Conclusion: In our study population, we found that moderate to severe glenoid dysplasia is not a rare entity as seen on MRI, with an incidence of 14.3%. Furthermore, we found that there is a statistically significant increase in the incidence of posterior labral tears associated with shoulders with moderate or severe glenoid dysplasia compared with those shoulders with no dysplasia or mild dysplasia as evaluated on MRI. Even when the mild cases were included, the incidence of posterior labral tears was significantly increased versus healthy subjects, indicating that even mild cases of glenoid dysplasia may be clinically relevant.

We have cloned a partial rat kidney cDNA that encodes a 72.5 kDa N terminal fragment of a third isoform of the M110 subunit of phosphatase 1. This new isoform contains an insert in the 542-597 position not present in the M110 previously cloned (Chen et al. (1994) FEBS Lett. 356, 51-55) from the same species. The encoded cDNA was expressed as a soluble GST-fusion protein in E. coli, and its ability to interact with native PP-1C was measured both in vitro and in permeabilized smooth muscle. In vitro, the fusion protein was capable of selectively binding PP-1C and increasing the substrate specificity of the phosphatase towards myosin 13.2 +/- 3.5-fold (S.E. of the mean, n = 3). In permeabilized smooth muscle pretreated with microcystin, the recombinant protein alone (1.0 microM) did not cause relaxation, but did significantly enhance the ability of PP-1C (0.3 microM) to relax the muscle. These findings show that the N terminal domain of the M110 subunit is the primary site for both PP-1C and myosin binding, and thereby determines myosin specificity. The presence of isoformic variation within this sequence may permit organ/cell specific regulation of phosphorylation sites.

We have purified 3500-fold from rabbit skeletal muscle a 12,020-Da mitogen-activated protein kinase kinase (MEK)-enhancing factor (MEF) that stimulates both mitogen-activated protein kinase (MAPK) autophosphorylation and the rate (24-fold) at which the enzyme is phosphorylated by MEK in vitro. This was manifest by the finding that in the presence of MEF, molar equivalents of MEK to MAPK were sufficient to produce fully phosphorylated (2.1 +/- 0.4 mol/mol; S.D., n = 3) and activated MAPK. This contrasted with the 40:1 molar excess ratio of MEK to MAPK required to produce fully phosphorylated and activated MAPK in the absence of MEF. Phosphoamino acid analysis revealed that in the presence of MEF, phosphorylation of MAPK by MEK was ordered, with Tyr-185 phosphorylation preceding Thr-183 phosphorylation. However, the rate at which Thr-183 was phosphorylated relative to Tyr-185 was greatly increased. The finding that MEF stimulated MAPK autophosphorylation and increased its ability to be phosphorylated by MEK suggests a mechanism of action in which MEF interacts with MAPK to alter its conformation.

1. Recombinant, activated mitogen-activated protein kinase (3.3 microM; p42mapk) phosphorylated caldesmon in phasic (rabbit portal vein) and tonic (rabbit femoral artery) smooth muscle strips permeabilized with Triton X-100. 2. Phosphorylation of caldesmon by p42mapk neither induced contraction of relaxed smooth muscle nor affected the Ca2+ sensitivity of submaximally contracted permeabilized phasic or tonic smooth muscle.

PHAS-I is a heat- and acid-stable protein that is phosphorylated on Ser/Thr residues in response to insulin and growth factors. To investigate the phosphorylation of PHAS-I, the protein was expressed in bacteria and purified for use as substrate in protein kinase reactions in vitro. Recombinant PHAS-I was rapidly and stoichiometrically phosphorylated by mitogen-activated protein (MAP) kinase. At saturating MgATP, the Km and Vmax observed with PHAS-I were almost identical to those obtained with myelin basic protein, one of the best MAP kinase substrates. PHAS-I was also phosphorylated at a significant rate by casein kinase II and protein kinase C. To investigate sites of phosphorylation, PHAS-I was digested with collagenase and phosphopeptides were resolved by reverse phase high performance liquid chromatography. Almost all of the phosphate introduced by MAP kinase was recovered in the peptide, Leu-Met-Glu-Cys-Arg-Asn-Ser-Pro-Val-Ala-Lys-Thr. 32P was released in the seventh cycle of Edman degradation, identifying the Ser (Ser64) as the phosphorylated residue. Ser64 was also phosphorylated in response to insulin in rat adipocytes. We conclude that PHAS-I is a substrate for MAP kinase both in vivo and in vitro. As PHAS-I is one of the most prominent insulin-stimulated phosphoproteins in adipocytes, it may qualify as the major MAP kinase substrate in these cells.

Treatment of adipocytes with insulin or phorbol 12-myristate 13-acetate (PMA) results in transient activation of mitogen-activated protein kinase kinase (MEK) (Tmax = 90 s) and mitogen-activated protein kinase (MAPK) (Tmax = 300 s). We have identified a novel insulin-stimulated MEK kinase (I-MEKK) in the 100,000 x g infranatant that shows rapid phasic kinetics that temporally precede that of MEK. Maximal activation of I-MEKK occurs within 20 +/- 5 s (S.D., n = 3) followed by complete inactivation by 30 +/- 10 s (S.D., n = 3). I-MEKK was characterized by anion-exchange and gel filtration chromatography and separated into two distinct activities of approximately 56 kDa that phosphorylated and activated MEK. I-MEKKs did not co-elute on anion exchange with c-Raf or 73-kDa MEK kinase (MEKK), suggesting they are distinct enzymes. Protein phosphatase 2A inactivated both I-MEKKs in vitro and in the intact cell okadaic acid blocked inactivation in the presence of insulin. These results suggest activation of I-MEKK involves phosphorylation on serine or threonine residues. I-MEKK was not activated by PMA, suggesting that in adipocytes the enzyme represents a divergence point between signal transduction pathways mediated by insulin and those activating protein kinase C.

Recently, Sowadski and colleagues [Knighton, D.R., Zheng, J., Eyck, L.F.T., Ashford, V.A., Xuong, N., Taylor, S.S. & Sowadski, J.M. (1991) Science 407, 407-420] reported the structure of a ternary complex of the catalytic subunit of cAMP-dependent protein kinase (cyclic A kinase), MgATP and a 20-residue inhibitor peptide, at a resolution of 0.27 nm. This structure has since been refined to 0.2-nm resolution and the orientation of the nucleotide and interactions of MgATP with numerous conserved residues at the active site defined [Zheng, J., Knighton, D.R., Eyck, L.F.T., Karlsson, R., Xuong, N., Taylor, S.S. & Sowadski, J.M. (1993) Biochemistry, in the press]. These studies revealed that the adenosine portion of ATP is buried deep within the catalytic cleft, with the alpha, beta and gamma phosphates protruding towards the opening of the cleft. The unique spatial positioning of MgATP within the catalytic cleft of cyclic A kinase and its interactions with conserved amino acids found in all protein kinases, led us to reconsider the use of ATP as an affinity ligand for the purification of these enzymes. In this paper, we describe a straightforward method for the synthesis of [gamma-32P]adenosine-5'-(gamma-4-aminophenyl)triphosphate for the covalent linkage of ATP to Sepharose through its gamma phosphate. In the presence of 20 microM ATP, adenosine-5'-(gamma-4-aminophenyl)triphosphate exhibited apparent Ki values of 103.6, 75.18, 176.28 and 120.00 microM against cyclic A kinase, mitogen-activated protein kinase (p42mapk), mitogen-activated protein kinase kinase and p60c-src, respectively. To illustrate the effectiveness of adenosine-5'-(gamma-4-aminophenyl)triphosphate-Sepharose as an affinity column for protein kinases, we have used the resin to purify rabbit skeletal muscle mitogen-activated protein kinase kinase over 19000-fold to homogeneity.

Mitogen-activated protein (MAP) kinases p42mapk and p44mapk are activated by dual tyrosine and threonine phosphorylation in vivo. Both MAPKs are phosphorylated and activated in vitro by an activator recently identified as a protein-tyrosine/threonine kinase. We have isolated a putative cDNA for a MAP kinase kinase (MAPKK) and determined its structure [Proc. Natl. Acad. Sci. USA, in press]. The protein encoded by this cDNA shares sequence homology with two yeast protein kinases byr1 and STE7. We now report that stimulation with serum of COS cells expressing this shares sequence homology with two yeast protein kinases byr1 and STE7. We now report that stimulation with serum of COS cells expressing this protein amplifies MAPK activator activity markedly. The increased activity co-migrates during chromatography with the expressed 45 kDa protein, recognized by an anti-STE7/byr1 antibody, and is abrogated by treatment with phosphatase 2A. Thus, this cDNA encodes a functional MAPKK. The anti-STE7/byr1 antibody also recognized a 46 kDa COS cell protein that was resolved from the expressed MAPKK by anion-exchange chromatography. This immunoreactive protein co-eluted with endogenous MAPKK activity, suggesting identification of the immunoreactive band as monkey MAPKK.

Preparation of milligram amounts of [32P]p42mapk, phosphorylated at Tyr185 or diphosphorylated at Tyr185/Thr183, for use as specific protein phosphatase substrates is described. Tyr- but not Thr-phosphorylated p42mapk, accumulates when ATP is limiting. Furthermore, Tyr185-phosphorylated p42mapk exhibits an apparent 10-fold decrease in apparent Km (46.6 +/- 6.6 nM) for MAP kinase kinase compared to that for the dephospho form (approximately 476 nM). We conclude that Tyr185 precedes Thr183 phosphorylation, and that this is prerequisite, dramatically increasing the affinity of p42mapk for MAP kinase kinase.