Validation of MRI biomarkers of hepatic steatosis in the presence of iron overload in the ob/ob mouse

Purpose:

To validate the utility and performance of a T correction method for hepatic fat quantification in an animal model of both steatosis and iron overload.

Materials and Methods:

Mice with low (n = 6), medium (n = 6), and high (n = 8) levels of steatosis were sedated and imaged using a chemical shift‐based fat‐water separation method to obtain magnetic resonance imaging (MRI) fat‐fraction measurements. Imaging was performed before and after each of two superparamagnetic iron oxide (SPIO) injections to create hepatic iron overload. Fat‐fraction maps were reconstructed with and without T correction. Fat‐fraction with and without T correction and T measurements were compared after each injection. Liver tissue was harvested and imaging results were compared to triglyceride extraction and histology grading.

Results:

Excellent correlation was seen between MRI fat‐fraction and tissue‐based fat quantification. Injections of SPIOs led to increases in R (=1/T). Measured fat‐fraction was unaffected by the presence of iron when T correction was used, whereas measured fat‐fraction dramatically increased without T correction.

Conclusion:

Hepatic fat‐fraction measured using a T‐corrected chemical shift‐based fat‐water separation method was validated in an animal model of steatosis and iron overload. T correction enables robust fat‐fraction estimation in both the presence and absence of iron, and is necessary for accurate hepatic fat quantification. J. Magn. Reson. Imaging 2012;35:844–851. © 2011 Wiley Periodicals, Inc.     

The 3,4-catechol derivative of propranolol, a minor dihydroxylated metabolite

The O,O-dibenzyl ether of the 3,4-catechol derivative of propranolol (11) was prepared to determine whether the catechol is a product of metabolic hydroxylation. 4-(Allyloxy)-1,2-naphthoquinone (5) was reduced with sodium dithionite and alkylated with benzyl chloride to produce ether 7. Osmium tetroxide oxidation of 7 afforded glycol 8. Subsequent monotosylation, oxirane formation with KOH, and opening with isopropylamine afforded benzyl ether 11. Although hydrogenolysis was successful, catechol 3 was rapidly oxidized to the corresponding o-quinone (12). Reduction of 12 with sodium bisulfite afforded 3, which was derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) to serve as a standard for the metabolic experiments. Gas chromatography-mass spectrometry of the Me3Si ethers of the products of metabolism of pseudoracemic propranolol (made up of equal molar (2R)-propranolol-d0/(2S)-propranolol-3',3'-d2) in the presence of the rat liver 9000g supernatant fraction showed four dihydroxylated metabolites, of which catechol 3 was in smallest amount, approximately 9% of the sum of dihydroxylated metabolites. Each of the four dihydroxylated propranolols arises stereoselectively from the 2R enantiomer of propranolol (by 1.15- to 2-fold), as determined by parent ion intensities at m/z 507 vs. 509. Quinone 12 was a nonselective competitive beta-adrenoceptor antagonist, being about 16-fold less potent than propranolol in both beta 1 and beta 2 assays.     

A report of 6 children with small bowel intussusception that required surgical intervention

Background/Purpose

We aim to justify the need for surgical intervention in our patients with childhood small bowel intussusceptions (SBIs) and review the current concepts in childhood SBI.

Materials and Methods

We retrospectively reviewed the clinical charts of all patients with surgically confirmed SBI between July 1999 and October 2002. Demographic data, clinical presentation and investigations, operative and pathologic findings, and outcome were analyzed.

Results

Of 173 patients with intussusception, 6 (3.5%) were diagnosed with SBI. Median age was 11 months. Ultrasonography revealed intussusceptions in all patients, but only 1 was diagnosed with SBI. Air enema reductions were attempted in 4 of 6 patients with all ending up in failure and surgery. Surgery revealed ileoileal intussusceptions in 4 patients and jejunojejunal intussusceptions in 2 patients. Two patients had long intussusceptions measuring between 30 and 50 cm in length. Five patients had pathologic lead points, and bowel complications occurred in 2 patients. All underwent bowel resection and primary anastomosis.

Conclusion

Despite reports on spontaneous reduction of SBI, surgery was unavoidable in all our patients with SBI because of the presence of pathologic lead points and/or bowel complications. Air enema reduction was ineffective in SBI. Due caution should be exercised when selecting patients for expectant management.     

Benefits of intracervical injection of sterile saline solution in laparoscopically assisted vaginal hysterectomy with vaginal colpotomy and bladder mobilization

OBJECTIVE: To evaluate the influence of intracervical saline injection on inexperienced operators and on laparoscopically assisted vaginal hysterectomy (LAVH). STUDY DESIGN: This retrospective study included 273 women undergoing LAVH. From July 1997 to June 2002, 138 LAVHs were performed with laparoscopically approached colpotomies and bladder mobilization. Among 135 LAVHs with a vaginal approach, colpotomies/bladder mobilization was done directly in 62 and in the other 73 after a circumferential intracervical saline injection. All operations were performed by inexperienced operators under the supervision of senior surgeons. Blood loss, operative time and complications were analyzed. RESULTS: The average follow-up period was 41.2 +/- 17.4 months (range, 12-72). No statistically significant differences were observed in age, hemoglobin levels or length of postoperative hospital stay. The incidence of postoperative infection, hematoma and bowel injury was not significantly different. LAVH with vaginal colpotomies/bladder mobilization and intracervical saline injection was associated with the smallest estimated blood loss (p = 0.002) and operative time (p < 0.001). LAVH with laparoscopic colpotomies and bladder mobilization had the longest operative time (p<0.001) and the highest bladder injury rate (p= 0.004). CONCLUSION: A circumferential injection of normal saline at the cervicovaginal junction is a good option for inexperienced operators.     

A comparative assessment of mandibular condylar position in patients with anterior disc displacement of the temporomandibular joint.

PURPOSE: The purpose of this study was to determine whether the position of the mandibular condyle in patients with anterior disc displacement (ADD) is different from that of a control group with normal joints using a novel method to quantify the irregular shape of the temporomandibular joint (TMJ). MATERIALS AND METHODS: Twenty-six magnetic resonance images of TMJs with ADD were evaluated and compared with 14 normal joints. The position of the condyle was determined by using 2 different methods: 1) measuring the horizontal and vertical normalized distances in millimeters between the geometric centers of the glenoid fossa and the condyle and 2) calculating the anteroposterior joint space ratio. RESULTS: Using the first method, the horizontal distance between the centers of the condyle and the glenoid fossa was 14.0 +/- 11.1 in the ADD group and 5.3 +/- 10.9 in the control group (P <.001). The vertical distance was 64.7 +/- 22.7 in the ADD group and 68.3 +/- 32.9 in the control group (P =.015). The ratio of the horizontal and the vertical condylar displacement in the ADD group was 2.4. Using the second method, the anteroposterior joint space ratios in the ADD group and in the control group were 1.7 +/- 0.5 and 1.2 +/- 0.4, respectively (P =.001). CONCLUSION: This study found that condyles of patients with ADD were situated more posterior and superior in the fossa than those in the control group. Moreover, in the ADD group, the posterior condylar displacement was noted to be 2.4 times greater than the superior condylar displacement.     

Expression of c-kit protooncogene in human hepatocellular carcinoma

Using comparative genomic hybridisation, DNA copy number changes were investigated in 15 cases of pigmented villonodular synovitis of the knee joint. Additionally DNA content was analysed by flow cytometry. Screening revealed numerical chromosomal imbalances in five of the examined cases. A total number of 18 gains were detected. The most frequent gains involved subregions of chromosomal arms 22q and 16p and 16q. No losses were found. One of the cases showed an aneuploid DNA-pattern, which actually proved to be the case with the most numerical chromosomal changes.