Ulnar nerve morphology on magnetic resonance imaging predicts nerve recovery after surgery for cubital tunnel syndrome

Magnetic resonance imaging (MRI) can evaluate nerve morphology in cubital tunnel syndrome (CuTS), but its value in predicting surgical outcome is unclear. The purpose of this study was to determine whether ulnar nerve morphology on MRI correlated with outcome after CuTS surgery. We reviewed 40 patients who had preoperative MRI and electrodiagnostic (EDX) examinations for CuTS and outcome evaluation 6 months and 2 years postoperatively. Using MRI, ulnar nerve cross-sectional area (UNCSA), changes in signal intensity, and any space-occupying lesion were evaluated. Other factors assessed were age, symptom duration and severity, type-2 diabetes and EDX parameters. Factors associated with unfavorable surgical outcome were identified. At 6 months postoperatively, 12 patients (30%) had excellent, 19 (47.5%) good, 8 (20%) fair and 1 (2.5%) poor results on modified Wilson-Krout criteria. On univariate analysis, unfavorable outcomes were associated with increased UNCSA, space-occupying lesion, and decreased motor nerve conduction velocity (mNCV), and on multivariate analysis with increased UNCSA 1 cm distal from the epicondyle only (model 1) or increased UNCSA 1 cm proximal from the epicondyle and decreased mNCV (model 2). At 2 years, 15 patients (37.5%) had excellent, 21 (52.5%) good, 3 (7.5%) fair and 1 (2.5%) poor results, and no factors correlated with unfavorable outcome. Increased UNCSA on MRI was associated with unfavorable outcome at 6 months but not at 2 years. This study suggests that morphologic ulnar nerve changes can predict delayed nerve recovery after surgery for CuTS.

MRI analysis of extra-capsular ganglia at the gastrocnemius origin and their association with osteoarthritis

AIM

To evaluate the prevalence, clinical relevance, and magnetic resonance imaging (MRI) features of extra-capsular ganglia at the gastrocnemius origin and to assess their association with internal derangement and osteoarthritis of the knee.

MATERIALS AND METHODS

One hundred consecutive knee MRI examinations, obtained within a 6-month period from patients with no history of recent knee trauma, recent injections, inflammatory arthritis, infection, or tumours, were evaluated retrospectively for the presence of ganglia at the gastrocnemius origin. The lesions were divided into two groups: an intra-capsular and an extra-capsular group. Cyst morphology (size, shape, and internal septa), internal derangement of the knee (cartilage lesion, cruciate ligament injury, meniscal tear, and corner injury on MRI, and osteoarthritis of the knee on radiographs) were evaluated. The chi-square, Fisher's exact, and t-tests were used to compare the two groups, in addition to multivariate stepwise logistic regression analysis.

RESULTS

Thirty-nine ganglia with an extra-capsular location were identified on 100 knee MRI (39 %). Rounded shape and internal septa were more common in the extra-capsular than in the intra-capsular group (p<0.001). Frequencies of high-grade cartilage, meniscal tear, and high-grade osteoarthritis significantly differed between the groups (p≤0.038). In multivariate analysis, the only significant association was between high-grade osteoarthritis and the extra-capsular group.

CONCLUSION

Extra-capsular ganglia at the gastrocnemius origin were not uncommon on knee MRI and had features typical of ganglia found at other sites. High-grade osteoarthritis was significantly associated with extra-capsular ganglia.

MR imaging of the neural foramina of the cervical spine: Comparison of 3D-DESS and 3D-FISP sequences

Purpose: To assess whether a single three-dimensional double-echo steady state (3D-DESS) sequence can produce equivalent results when compared to a 3D free induction with steady precession (3D-FISP) sequence for the evaluation of the neural foraminal diameter and structures.

Material and Methods: Five phantoms were imaged on CT with 3-mm axial slices followed by reformatted axial 3D-DESS and 3D-FISP sequences. In addition, 3D-DESS and 3D-FISP sequences of 20 healthy subjects were compared with regard to image quality, differentiation between vertebrae and discs, differentiation between discs and neural foramina, and differentiation between vertebrae and neural foramina.

Results: Compared with CT, 3D-DESS and 3D-FISP sequences consistently underestimated the diameters of the neural foramina. The mean difference values for the 3D-DESS was 12.8%, compared to 9.5% for the 3D-FISP sequence. Concerning the in vivo studies, the 3D-DESS sequence was superior but not statistical significant to the 3D-FISP sequence with regard to image quality, differentiation between vertebrae and discs, differentiation between discs and neural formina, and identification of the nerve roots.

Conclusion: The 3D-DESS sequence is moderately accurate in the evaluation of the neural foraminal size. Compared to the 3D-FISP sequence, the 3D-DESS sequence is compatible concerning the image quality, differentiation between the cervical vertebrae and discs, and between the discs and neural foramina.

Critical role of duplex ultrasonography for the advanced management of a venous malformation

Objectives: Duplex ultrasonography was assessed for its advanced role as a contemporary guide for the safer management of venous malformation (VM) at the lower extremities through a comparison study with matching magnetic resonance imaging (MRI) and/or ascending phlebography findings.

Methods: A retrospective review of 50 patients with a VM in the lower extremities was performed using the duplex scan findings on the initial diagnosis and the subsequent follow-up assessment of the treatment response. The screening findings of deep vein thrombosis (DVT) development following ethanol sclerotherapy on 40 patients were also included. A marginal vein (lateral embryonal) compression test was also performed on 10 patients, who were candidates for a resection preoperatively, in order to assess its value in predicting the response to the subsequent resection. The duplex scan findings were compared with the available ascending phlebography results in 38 patients, and also with the MRI findings available for all 50 patients.

Results: The duplex scan on the 50 patients confirmed the existence of a normal deep vein system in the lower extremities in 43 patients as the true-positive test findings. One false-negative test finding was subsequently confirmed by an angiographic evaluation. The duplex scan also confirmed the absence of a normal deep vein system in four patients as a true-negative test. MRI subsequently confirmed two false-positive findings in one patient, and angiography confirmed two false-positive findings in another (sensitivity − 97.8%, specificity − 66.7%, positive predictive value − 95.6%, and negative predictive value − 80%). Among a total of 40 patients who received ethanol sclerotherapy, the duplex scan identified DVT in three patients, and also screened out properly in 37 patients through a total of 185 ethanol sclerotherapy sessions. The compression test predicted the surgical outcome successfully in the majority (7/8). The duplex scan appears to have comparable reliability to MRI and/or angiography for diagnosing and managing VM.

Conclusions: The duplex scan can provide the critical haemodynamic information of both the deep venous system and VM lesions quite effectively with the cost-effectiveness of a non-invasive test. In particular, the duplex scan is an excellent test for the safe management of VM of the lower extremity, including the early detection of DVT through multi-session ethanol sclerotherapy.

Overcoming aggregation in indium salen catalysts for isoselective lactide polymerization

A methodology for controlling aggregation in highly active and isoselective indium catalysts for the ring opening polymerization of racemic lactide is reported. A series of racemic and enantiopure dinuclear indium ethoxide complexes bearing salen ligands [(ONNOR)InOEt]2 (R = Br, Me, admantyl, cumyl, t-Bu) were synthesized and fully characterized. Mononuclear analogues (ONNOR)InOCH2Pyr (R = Br, t-Bu, SiPh3) were synthesized by controlling aggregation with the use of chelating 2-pyridinemethoxide functionality. The nuclearity of metal complexes was confirmed using PGSE NMR spectroscopy. Detailed kinetic studies show a clear initiation period for these dinuclear catalysts, which is lacking in their mononuclear analogues. The polymerization behavior of analogous dinuclear and mononuclear compounds is identical and consistent with a mononuclear propagating species. The isotacticity of the resulting polymers was investigated using direct integration and peak deconvolution methodologies and the two were compared.

Influence of hepatitis B virus reactivation on the recurrence of HBV-related hepatocellular carcinoma after curative resection in patients with low viral load

It is unclear whether the reactivation of hepatitis B virus (HBV) influences the prognosis of hepatocellular carcinoma (HCC) after resection in patients with chronic hepatitis B. The aim of this study was to identify the influence of HBV reactivation on the recurrence of hepatitis B-related HCC after curative resection in patients with low viral load (HBV DNA <2000 IU/mL). We retrospectively analysed a total of 130 patients who underwent curative resection for HBV-related early stage HCC (single nodule; <5 cm/two or three nodules; <3 cm) with pre-operative HBV DNA levels <2000 IU/mL with serial HBV DNA tests. The predictive factors including HBV reactivation for the recurrence of HBV-related HCC after curative resection were investigated. Fifty-three patients (41%) had HBV reactivation after resection among 130 patients. HBV reactivation was observed in 22 of 53 patients with undetectable baseline HBV DNA and in 31 of 77 patients with detectable baseline HBV DNA. Cumulative recurrence rates after resection at 1, 2 and 3 years were 17.0%, 23.3% and 31.4%, respectively. The multivariable analysis demonstrated that the risk factors for the recurrence were the presence of microvascular invasion (hazard ratio (HR) 2.62, P = 0.003), multinodularity (HR 4.61, P = 0.005), HBV reactivation after resection (HR 2.03, P = 0.032) and HBeAg positivity (HR 2.06, P = 0.044). HBV reactivation after curative resection is associated with the recurrence of HBV-related HCC in patients with low viral load.

Comparison of three-dimensional isotropic and conventional MR arthrography with respect to the diagnosis of rotator cuff and labral lesions: focus on isotropic fat-suppressed proton density and VIBE sequences

AIM

To compare the diagnostic accuracies of three-dimensional (3D) isotropic magnetic resonance arthrography (MRA) using fat-suppressed proton density (PD) or volume interpolated breath-hold examination (VIBE) sequences with that of conventional MRA for the diagnosis of rotator cuff and labral lesions.

MATERIALS AND METHODS

Eighty-six patients who underwent arthroscopic surgery were included. 3D isotropic sequences were performed in the axial plane using fat-suppressed PD (group A) in 53 patients and using VIBE (group B) in 33 patients. Reformatted images were obtained corresponding to conventional images, and evaluated for the presence of labral and rotator cuff lesions using conventional and 3D isotropic sequences. The diagnostic performances of each sequence were determined using arthroscopic findings as the standard.

RESULTS

Good to excellent interobserver agreements were obtained for both 3D isotropic sequences for the evaluation of rotator cuff and labral lesions. Excellent agreement was found between two-dimensional (2D) and 3D isotropic MRA, except for supraspinatus tendon (SST) tears by both readers and for subscapularis tendon (SCT) tears by reader 2 in group B. 2D MRA and 3D isotropic sequences had high diagnostic performances for rotator and labral tears, and the difference between the two imaging methods was insignificant.

CONCLUSIONS

The diagnostic performances of 3D isotropic VIBE and PD sequences were similar to those of 2D MRA.

Electrohydraulic pump-driven closed-loop blood pressure-regulatory system

In this paper, we describe our design for a new electrohydraulic (EH) pump-driven renal perfusion pressure (RPP)-regulatory system capable of implementing precise and rapid RPP regulation in experimental animals. Without this automated system, RPP is manually controlled via a blood pressure clamp, and the imprecision in this method leads to compromised RPP data. This motivated us to develop an EH pump-driven closed-loop blood pressure regulatory system based on flow-mediated occlusion using the vascular occlusive cuff technique. A closed-loop servo-controller system based on a proportional plus integral (PI) controller was designed using the dynamic feedback RPP signal from animals. In vivo performance was evaluated via flow-mediated RPP occlusion, maintenance, and release responses during baseline and ANG II-infused conditions. A step change of -30 mmHg, referenced to normal RPP, was applied to Sprague-Dawley rats with the proposed system to assess the performance of the PI controller. The PI's performance was compared against manual control of blood pressure clamp to regulate RPP. Rapid RPP occlusion (within 3 s) and a release time of approximately 0.3 s were obtained for the PI controller for both baseline and ANG II infusion conditions, in which the former condition was significantly better than manual control. We concluded that the proposed EH RPP-regulatory system could fulfill in vivo needs to study various pressure-flow relationships in diverse fields of physiology, in particular, studying the dynamics of the renal autoregulatory mechanisms.

Contemporary diagnosis and management of venous and arterio-venous shunting malformation by whole body blood pool scintigraphy

AIM

Various non- to less-invasive tests have been recently introduced in the management of congenital vascular malformations (CVM) and have become essential for the initial diagnostic work-up, largely replacing the traditional role of invasive tests. Whole body blood pool scintigraphy (WBBPS) was initially adopted as a supplementary test to reinforce other well-established essential diagnostic tests, and has been used extensively together in our Clinic, for years. We have evaluated WBBPS retrospectively for the diagnosis of venous malformation (VM) and arterio-venous malformation (AVM), and also for a further possible role for the interim assessment of treatment results during multistaged embolo/sclerotherapy.

METHODS

Of 123 VMs and 48 AVMs selected for various treatments, 80 patients (66 VMs and 14 AVMs) were reviewed. The reliability of WBBPS as an initial diagnostic tool for VMs and AVM was assessed first by comparing its findings with matching MRI and/or duplex scan findings. These 80 patients underwent embolo/sclerotherapy with absolute ethanol mostly for VM, and N-butyl cyanoacrylate for AVM. A total of 251 sessions were performed either as a primary treatment independently or in conjunction with surgical treatment preoperatively. Thirty-six patients were available in terms of the subsequent review of the treatment results, to compare their 72 post-therapy WBBPS findings with matching duplex scan and MRI findings. The WBBPS assessment of treatment response was based on the percentage reduction of abnormal blood pooling over the region of interest (ROI) from baseline (initial) value. Treatment response was also qualitatively and semi-quantitatively assessed according to the degree of abnormal blood pool reduction.

RESULTS

Of the 80 CVM (66 VM and 14 AVM) patients, 61 of 66 WBBPS findings of VM on initial diagnosis were confirmed as true-positive. Twelve of 14 AVMs were also confirmed as WBBPS true-positive findings. The sensitivity of WBBPS for the initial diagnosis was 93.8% (61/65) for VM and 92.3% (12/13) for AVM. The positive predictive value was 98.4% (61/62) for VM and 92.3% (12/13) for AVM. Of 72 post-therapy WBBPS performed for follow-up assessment of the results of treatment on 36 patients, 52 WBBPS showed positive findings qualitatively and/or quantitatively, the remaining 20 were negative. Fifty-one of the 52 WBBPS-positive findings were true-positive and 18 of the 20 were true-negative. Hence, WBBPS for follow-up assessment showed a sensitivity of 96% (51/53); a specificity of 95% (18/19); a positive predictive value of 98% (51/52); and a negative predictive value of 90% (18/20).

CONCLUSIONS

Contemporary management of CVMs can be improved by using WBBPS, which is a less expensive, simple, and safe non-invasive test, especially for venous and arterio-venous malformations. WBBPS is a cost-effective and practical test with dependable accuracy for the assessment of treatment results, especially for interim measurements during multistage embolo/sclerotherapy.

Risk factors of new compression fractures in adjacent vertebrae after percutaneous vertebroplasty

PURPOSE

To evaluate the risk factors related to the development of new fractures in adjacent vertebrae after vertebroplasty.

MATERIAL AND METHODS

The study was conducted on 106 patients in whom 212 vertebroplasties were performed during a period of 3 years. Evaluations of the five vertebrae superior and inferior to the treated vertebra were performed. Consequently, 913 vertebrae were evaluated and the fracture-free interval of the vertebral body adjacent to the treated vertebra was calculated. Survival analysis was performed using the Kaplan-Meier method and Cox proportional hazards regression analysis.

RESULTS

Seventy-two (7.9%) new fractures were revealed. The Kaplan-Meier estimate of the 1-year fracture-free rate was 93.1%. The mean fracture-free interval was 32 months (95% CI, 32 to approximately 33 months). The greater degree of height restoration of the treated vertebra, the location of the adjacent vertebra in the TL junction, and the shorter distance between the treated and the adjacent vertebra increased the risk of new vertebral fractures.

CONCLUSION

Thoracolumbar junction, shorter distance from the treated vertebrae, and greater degree of height restoration of the cemented vertebrae may increase the fracture risk of vertebrae adjacent to cement vertebrae after vertebroplasty.

Imaging features of ischial bursitis with an emphasis on ultrasonography

OBJECTIVE

The aim of this study was to evaluate the imaging features of ischial bursitis with an emphasis on ultrasonography (US).

DESIGN AND PATIENTS

Our study included 31 patients with a painful mass or tenderness in their buttock who underwent US (n=27), CT (n=1), or MR imaging (n=4). A needle aspiration (n=6) or a bursal excision (n=5) was performed in those patients who had no clinical improvement in spite of the conservative treatment. Evaluation included lesion location, size, wall of the bursae, and intrinsic characteristics on US, CT and MR imaging.

RESULTS

Ischial bursitis was superficial to the ischial tuberosity in all patients (n=31). The lesion ranged from 1.5 cm to 7 cm (average 3.8 cm) in diameter. The bursal wall was identifiable in 25 cases (81%). Internal septa and mural nodules were seen in 12 (39%) and 17 cases (55%), respectively. Sonography showed that fluid within the bursa was hypoechoic (59%), hyperechoic (26%), or of mixed echogenicity (15%). The bursae were compressible by the transducer. Power Doppler examination (n=7) showed hypervascularity of the bursal wall. All lesions imaged with contrast-enhanced CT and MR imaging had an enhancing thin wall and mural nodule.

CONCLUSIONS

Ischial bursitis, superficial to the ischial tuberosity, can be clearly demonstrated on sonography and appears as a thin-walled cystic lesion, with or without internal septa and mural nodules.

A new approach to search for the bioactive conformation of glucagon: positional cyclization scanning

In search for the bioactive conformation of glucagon, "positional cyclization scanning" was used to determine secondary structures of glucagon required for maximal interaction with the glucagon receptor. Because glucagon is flexible in nature, its bioactive conformation is not known except for an amphiphilic helical conformation at the C-terminal region. To understand the conformational requirement for the N-terminal region that appears to be essential for signal transduction, a series of glucagon analogues conformationally constrained by disulfide or lactam bridges have been designed and synthesized. The conformational restrictions via disulfide bridges between cysteine i and cysteine i + 5, or lactam bridges between lysine i and glutamic acid i + 4, were applied to induce and stabilize certain corresponding secondary structures. The results from the binding assays showed that all the cyclic analogues with disulfide bridges bound to the receptor with significantly reduced binding affinities compared to their linear counterparts. On the contrary, glucagon analogues containing lactam bridges, in particular, c[Lys(5), Glu(9)]glucagon amide (10) and c[Lys(17), Glu(21)]glucagon amide (14), demonstrated more than 7-fold increased receptor binding affinities than native glucagon. These results suggest that the bioactive conformation of glucagon may adopt a helical conformation at the N-terminal region as well as the C-terminal region, which was not evident from earlier biophysical studies of glucagon.

Development of potent glucagon antagonists: structure-activity relationship study of glycine at position 4

We examined the functional role of glycine at position 4 in the potent glucagon antagonist [desHis(1), Glu(9)]glucagon amide, by substituting the L- and D-enantiomers of alanine and leucine for Gly(4) in this antagonist. The methyl and isobutyl side-chain substituents were introduced to evaluate the preference shown by the glucagon receptor, if any, for the orientation of the N-terminal residues. The L-amino acids demonstrated only slightly better receptor recognition than the D-enantiomers. These results suggest that the Gly(4) residue in glucagon antagonists may be exposed to the outside of the receptor. The enhanced binding affinities of analogs 1 and 3 compared with the parent antagonist, [desHis(1), Glu(9)]glucagon amide, may have resulted from the strengthened hydrophobic patch in the N-terminal region and/or the increased propensity for a helical conformation due to the replacement of alanine and leucine for glycine. Thus, as a result of the increased receptor binding affinities, antagonist activities of analogs 1-4 were increased 10-fold compared with the parent antagonist, [desHis(1), Glu(9)]glucagon amide. These potent glucagon antagonists have among the highest pA(2) values of any glucagon analogs reported to date.

IFN-gamma induces cell death in human hepatoma cells through a TRAIL/death receptor-mediated apoptotic pathway

We demonstrated the induction of cell death in a hepatoma cell line by IFN-gamma and its possible mechanism. Among the 2 hepatitis B virus (HBV)-associated hepatoma cell lines, SNU-354 and SNU-368, IFN-gamma induced cell death and increased caspase-3 activity in SNU-368 but not in SNU-354. IFN-gamma induced several changes in the mRNA expression level of apoptosis-regulating genes, e.g., increased expression of Fas, caspase-1 and TNF-related apoptosis-inducing ligand (TRAIL). In particular, IFN-gamma potently increased the mRNA expression of TRAIL in both cell lines. However, it did not change the mRNA expression level of death-mediating TRAIL receptors, e.g., DR4 and DR5, which were constitutively expressed in both cell lines. In contrast, the decoy receptor DcR1 was expressed in SNU-354 but not in SNU-368, and its expression level in SNU-354 was increased by IFN-gamma. Another decoy receptor, DcR2, was constitutively expressed in both cell lines; however, its expression level in SNU-368 was decreased by IFN-gamma. In addition, exogenous recombinant TRAIL reduced viability in SNU-368, but not in SNU-354, cells. From these findings, we speculated that TRAIL up-regulation and the subsequent TRAIL-mediated apoptosis serve as a mechanism of IFN-gamma-induced cell death in SNU-368. To confirm this hypothesis, we demonstrated that soluble DR4-Fc fusion protein, a TRAIL pathway inhibitor, inhibited IFN-gamma-induced cell death in SNU-368. Our results demonstrated that IFN-gamma acts as an inducer of cell death through TRAIL-mediated apoptosis.

In vivo changes in the neuroforaminal size at flexion-extension and axial rotation of the cervical spine in healthy persons examined using kinematic magnetic resonance imaging

STUDY DESIGN

In vivo flexion-extension and axial rotation magnetic resonance imaging (MRI) studies of the cervical spine were performed inside a positioning device.

OBJECTIVE

To determine the functional changes of neuroforaminal size that occur during flexion-extension and axial rotation of the cervical spine in healthy persons.

SUMMARY OF BACKGROUND DATA

Kinematic MRI studies of the cervical spine were performed to obtain detailed information about the functional changes that occur in neuroforaminal size during flexion-extention and axial rotation. The results were compared with published data of in vitro functional flexion-extension and axial rotation studies of the cervical spine.

METHODS

Inside a positioning device, the cervical spines of 30 healthy persons were examined in a whole-body magnetic resonance scanner from 40 degrees of flexion to 30 degrees of extension at nine different angle positions. In addition, axial rotation was performed at neutral position (0 degrees ) and at 20 degrees and 40 degrees of axial rotation to both sides. The images were analyzed with respect to the neuroforaminal size at each position using a reformatted 3D-FISP sequence.

RESULTS

At flexion, widening of the neuroforaminal size of up to 31% (compared with neutral position, 0 degrees ) was observed. Conversely, at extension a decrease in the size of the neuroforamen of up to 20% was recognized. At 20 degrees and 40 degrees of ipsilateral rotation of the head, a reduction in the neuroforaminal size of up to 15% and 23%, respectively, compared with the neutral position was noted. In contrast, a widening of the foraminal size was recognized on the contralateral side of 9% and 20% at 20 degrees and 40 degrees rotation. Statistically significant differences (p <== 0.05) were found in the neuroforaminal size between different degrees of flexion and extension and in addition for axial rotation compared to neutral position (0 degrees ).

CONCLUSION

Compared with the results of previous biomechanical studies of human cadaver cervical spines, kinematic MRI provides additional noninvasive data concerning the physiological changes of the neuroforaminal size during flexion-extension and axial rotation in healthy individuals.

Development of potent truncated glucagon antagonists

In pursuit of truncated glucagon analogues that can interact with the glucagon receptor with substantial binding affinity, 23 truncated glucagon analogues have been designed and synthesized. These truncated analogues consist of several fragments of glucagon with 11 or 12 amino acid residues (1-4), conformationally constrained analogues containing the sequence of the middle region of glucagon (5-15), and truncated analogues containing the sequence of the C-terminal region (16-23). Biological assays of these analogues showed that the truncated glucagon analogues with the sequence of the C-terminal region possess significantly better binding affinity compared to the truncated analogues with the sequence of the middle region, and these analogues (17-23) demonstrated potent antagonistic activity (pA(2) values between 6.5 and 7.5). On the basis of these results, it can be suggested that glucagon interacts with its receptor with two hydrophobic patches located in the middle and the C-terminal regions of glucagon, and both hydrophobic patches are necessary for significant receptor recognition. These two hydrophobic binding motifs, located in two different regions of glucagon, appear to be the reason why the earlier attempts to obtain truncated analogues with good binding affinity did not result in any success. Long peptide hormones such as glucagon seem to require more than one binding pocket on the receptors for maximal interaction.

Tuberculous versus pyogenic arthritis: MR imaging evaluation

PURPOSE

To assess magnetic resonance (MR) imaging features in differentiating tuberculous arthritis from pyogenic arthritis.

MATERIALS AND METHODS

Findings in 29 patients with tuberculous arthritis were compared with those of 13 patients with pyogenic arthritis. Bone erosion, marrow signal intensity, synovial lesion signal intensity, boundaries (smooth or irregular) for extraarticular extension of infection, and abscess rim enhancement (thin and smooth or thick and irregular) were analyzed.

RESULTS

Bone erosion was more common in patients with tuberculous arthritis (24 [83%] of 29) than in those with pyogenic arthritis (six [46%] of 13) (P =.026), while subchondral marrow signal intensity abnormality was seen more frequently in patients with pyogenic arthritis (12 [92%] of 13) than in those with tuberculous arthritis (17 [59%] of 29) (P =.036). On T2-weighted images, there was no significant difference between the synovial lesion signal intensities of tuberculous arthritis and pyogenic arthritis. Lesions in 16 (70%) of 23 patients with tuberculous arthritis and two (17%) of 12 patients with pyogenic arthritis had smooth extraarticular boundaries, while those in seven (30%) of 23 patients with tuberculous arthritis and 10 (83%) of 12 patients with pyogenic arthritis had irregular boundaries (P =.005). Tuberculous abscesses (16 [100%] of 16) had thin and smooth rim enhancement, while most pyogenic abscesses (five [71%] of seven) had thick and irregular rims (P =.001).

CONCLUSION

MR imaging of bone abnormalities, extraarticular lesions, and associated abscesses provides useful information in the differentiation of tuberculous arthritis and pyogenic arthritis.

Analysis of patellar cartilage. Comparison of conventional MR imaging and MR and CT arthrography in cadavers

OBJECTIVE

To compare the sensitivity of conventional MR sequences, MR arthrography, and CT arthrography for the detection of cartilage lesions of the patella in cadavers.

MATERIAL AND METHODS

Cartilage lesions in 10 cadaveric specimens were evaluated by MR imaging, including T1-weighted, proton density-weighted and T2-weighted sequences, and fat-suppressed spoiled gradient recalled acquisition in the steady state (SPGR), MR arthrography including T1-weighted and SPGR sequences, and double-contrast CT arthrography including conventional and subtracted images. The sensitivities with regard to detection of lesions were compared to results from morphologic and histologic investigations of sectioned specimens.

RESULTS

Twenty-one lesions were detected morphologically. For the detection of these lesions, sensitivities were as follows: T1-weighted images 33.3%; proton density-weighted images 85.7%; T2-weighted images 85.7%; SPGR images 80.9%; MR arthrography with T1-SE sequences 57.1%; MR arthrography with SPGR sequence 90.5%; and CT arthrography, both regular and subtracted images 85.7%.

CONCLUSION

For noninvasive techniques, T2-weighted images revealed the highest sensitivity for the detection of patellar cartilage lesions, which was surpassed only by MR arthrography using the SPGR sequence. CT arthrography delineated surface irregularities but failed to demonstrate intrachondral lesions.

Design and synthesis of conformationally constrained glucagon analogues

Glucagon was systematically modified by forming lactam bridges within the central region of the molecule to give conformationally constrained cyclic analogues. Six cyclic glucagon analogues have been designed and synthesized. They are c[Asp(9),Lys(12)][Lys(17,18), Glu(21)]glucagon-NH(2) (1), c[Asp(9),Lys(12)]glucagon-NH(2) (2), c[Lys(12),Asp(15)]glucagon-NH(2) (3), c[Asp(15), Lys(18)]glucagon-NH(2) (4), [Lys(17)-c[Lys(18), Glu(21)]glucagon-NH(2) (5), and c[Lys(12),Asp(21)]glucagon-NH(2) (6). The receptor binding potencies and receptor second messenger activities were determined by radio-receptor binding assays and adenylate cyclase assays, respectively, using rat liver plasma membranes. Most interestingly, analogues 1, 2, 3, and 4 were antagonists of glucagon stimulated adenylate cyclase activity, whereas analogues 5 and 6 were partial agonists in the functional assay. All of the cyclic analogues were found to have reduced binding potencies relative to glucagon. The structural features that might be responsible for these effects were studied using circular dichroism spectroscopy and molecular modeling. These results demonstrated the significant modulations of both receptor binding affinity and transduction (adenylate cyclase activity) that can accompany regional conformational constraints even in larger polypeptide ligands. These studies suggest that the entire molecular conformation, including the flexible middle portion, is important for molecular recognition and transduction at the hepatic glucagon receptor.

Effect of low back posture on the morphology of the spinal canal

OBJECTIVE

To define the possible mechanism of posture-dependent symptoms of spinal stenosis by measuring the effect of low back posture on morphologic changes of the intervertebral discs and spinal canal in healthy young people.

DESIGN

Twenty healthy young volunteers underwent magnetic resonance imaging while supine with their spine in neutral, flexed, extended, and right and left rotational positions. The axial MR images at the middle of the intervertebral discs of L3-4 and L4-5 were analyzed to measure the difference in the size and shape of the intervertebral discs and spinal canal in each posture.

RESULTS

Extension or rotation decreased the sagittal diameters and cross-sectional areas of the dural sac and spinal canal and increased the thickness of the ligamentum flavum, whereas flexion had the opposite effects. The gap between the convex posterior disc margin and the anterior margin of the facet joint on each side, represented as the subarticular sagittal diameter, increased with flexion and decreased with extension or rotation. The direction of rotation did not result in asymmetry of the subarticular sagittal diameter, but right rotation caused thickening of the right ligamentum flavum, and vice versa. The shape and dimensions of the disc did not change significantly according to the positions of the low back.

CONCLUSIONS

With extension or rotation, the thickness of the ligamentum flavum increased and the posterior margin of the intervertebral disc was approximated to the facet joint without any change in shape and size of the disc. These phenomena result in a decrease in the size of the spinal canal and dural sac in extension or rotation postures in young healthy people without disc degeneration, and may explain the posture-dependent symptom of spinal stenosis.

Infantile fibromatosis in childhood: findings on MR imaging and pathologic correlation

AIM

The objective of this study was to analyse the MR imaging findings of infantile fibromatosis of childhood and to correlate them with histopathological features.

MATERIALS AND METHODS

Seven patients with histologically proven infantile fibromatosis were included in this study. The findings on MR images were retrospectively evaluated and then correlated with the pathological features. Findings on MR imaging evaluated included signal intensity, extent of hyperintense area on T2-weighted images, margins of the lesion, the degree and pattern of enhancement and the presence of fatty tissue. Pathological features evaluated included cellularity, collagenization, and myxoid change. A five point scale was used for the evaluation of the extent of hyperintense area on MR imaging, and each of pathological features.

RESULTS

On T1-weighted images, the lesions were iso-intense in two patients; iso- and hypointense in three; and iso-, hypo- and hyperintense in two. On T2-weighted images, iso-, hypo- and hyperintense areas were mixed in all patients, the hyperintense area being the largest portion of the lesion. The margins of the lesions were infiltrative in four patients (57%), smooth in two (29%) and mixed in one (14%). Enhancement was marked in five patients (72%) and diffuse in five (71%). Regardless of the hyperintense signal intensity on T2-weighted images, the grades of each pathologic feature were variable.

CONCLUSION

Infantile fibromatosis on MR imaging causes an enhancing mass, that is largely hyperintense on T2-weighted images. Areas of high signal intensity on T2-weighted images corresponded to variable grades of cellularity, collagenization, or myxoid change.

Transverse ligament and its effect on meniscal motion. Correlation of kinematic MR imaging and anatomic sections

RATIONALE AND OBJECTIVES

To evaluate the effect of the transverse ligament on translation of the menisci.

METHODS

Six cadaveric knees were examined by MR imaging inside a positioning device before and after transecting the transverse ligament. The knees were examined at various positions: extension, 30 degrees of flexion, 60 degrees of flexion, and full flexion. Sagittal T1-weighted spin-echo images were generated at each knee position and evaluated for statistical differences with regard to anterior-posterior meniscal excursion.

RESULTS

Statistically significant differences in meniscal excursion were found before and after transsecting the transverse ligament for anterior-posterior meniscal motion of the anterior horn of the medial meniscus at 30 degrees of knee flexion. No such significant differences were found, however, at 60 degrees of flexion and full flexion in anterior-posterior meniscal excursion of the anterior or posterior horn of either meniscus before and after transsecting the transverse ligament.

CONCLUSIONS

The transverse ligament has a restricting effect on anterior-posterior excursion of the anterior horn of the medial meniscus at lower degrees of knee flexion.

Intramuscular vascular malformations of an extremity: findings on MR imaging and pathologic correlation

OBJECTIVE

To analyze the findings of intramuscular vascular malformations of an extremity on MR imaging and to correlate these findings with histopathologic examination.

DESIGN AND PATIENTS

The findings on MR imaging and the medical records of 14 patients with an intramuscular vascular malformation of the extremity were retrospectively studied. All patients underwent surgical excision. Diagnoses were based on the results of pathologic examination. Findings on MR imaging were noted and correlated with the histopathologic findings.

RESULTS

Intramuscular vascular malformations of an extremity showed multi-septate, honeycomb, or mixed appearance on MR imaging. Multi-septate areas correlated with dilated and communicating vascular spaces with flattened endothelium. Honeycomb areas corresponded to vascular spaces with inconspicuous small lumina and thickened vascular walls. Areas of increased signal intensity on T2-weighted images were found in all intramuscular vascular malformations. Infiltrative margins were more commonly seen in intramuscular lymphaticovenous malformations. Adherence to neurovascular structures and orientation of the lesion along the long axis of the affected muscle were more commonly seen in intramuscular venous malformations.

CONCLUSIONS

Intramuscular vascular malformations showed either a multi-septate, honeycomb, or mixed appearance, reflecting the size of the vascular spaces and the thickness of the smooth muscles of the vessel walls. Prediction of the subtype of an intramuscular vascular malformation of an extremity on MR imaging seems to be difficult, although there are associated findings that may be helpful in the differential diagnosis of each subtype.

Transforming growth factor-alpha and rhinitis

OBJECTIVES

Transforming growth factor-alpha (TGF-alpha) has been implicated in diverse physiologic and pathophysiologic functions including immunological, inflammatory, and neoplastic processes. TGF-alpha has been localized in the hyperproliferative, inflammatory environment of chronic otitis media, cholesteatoma, and asthmatic airways. TGF-beta1, which must be present with TGF-alpha to transform fibroblasts, has been found in rhinitic mucosa and in asthma in prior studies. The authors sought to identify whether TGF-alpha also played a role in the inflammatory cascade and fibrosis of rhinitis.

STUDY DESIGN

A nonrandomized, prospective study was carried out in which samples of inferior turbinate and nasal polyps from rhinitic and nonrhinitic patients were subjected to immunohistochemistry and Western blotting to determine the presence of TGF-alpha.

METHODS

Twenty-seven subjects undergoing surgery for rhinitis, obstructive sleep apnea, nasal fracture, and rhinoplasty were recruited for this study, the latter three groups acting as controls. Immunohistochemical and Western blotting techniques were employed to identify the presence of TGF-alpha in inferior-turbinate and nasal-polyp samples of rhinitic subjects.

RESULTS

Immunohistochemistry demonstrated the selective staining of TGF-alpha in the basement membrane and extracellular matrix, including lymphatic, vascular, and glandular structures, in most turbinate samples and the absence of staining in corresponding controls. Further, TGF-alpha was isolated to a discrete 30-kD band in both inferior turbinate and polyp tissues by Western blotting without staining in the corresponding controls.

CONCLUSIONS

These results suggest that TGF-alpha may play a role in the inflammatory derangement of rhinitis.

Right paratracheal air cysts in the thoracic inlet: clinical and radiologic significance

OBJECTIVE

The purpose of our study was to determine the CT appearance and clinical significance of a right paratracheal air cyst at the level of the thoracic inlet.

MATERIALS AND METHODS

Sixty-five consecutive patients with paratracheal air cysts were included in this study. The location, level, size, and shape of the paratracheal air cysts on CT were analyzed. The spirometric data, tracheal indexes, and CT-determined emphysema scores of these patients were compared with those of 60 consecutive patients in a control group.

RESULTS

The air cysts were located at the right posterolateral aspect of the trachea in 64 (98%) of 65 patients and at T1-T2 vertebral levels in 57 (88%) of 65 patients. The mean diameter of the right paratracheal cysts was 10 mm in the axial plane and 14 mm in the vertical plane. CT showed a communicating channel with the trachea in five patients. The ratio of forced expiratory volume obtained in 1 sec to forced vital capacity, and forced expiratory flow between 25% and 75% of vital capacity in patients with paratracheal air cysts, were significantly lower than those of the control group (p < .05). Differences in the tracheal indexes and CT-determined emphysema scores between the study group and the control group were found to be statistically significant (p = .001).

CONCLUSION

The most probable nature of a right paratracheal cyst in the thoracic inlet is tracheal diverticulum with a narrow stalk. The presence of a right paratracheal air cyst on CT could be a sign of obstructive lung disease clinically and of the presence of emphysema radiologically.

Iliotibial band friction syndrome: MR imaging findings in 16 patients and MR arthrographic study of six cadaveric knees

PURPOSE

To define magnetic resonance (MR) imaging findings in patients with the iliotibial band friction syndrome (ITBFS) and to correlate these findings with anatomic features defined at magnetic resonance (MR) arthrography in cadavers.

MATERIALS AND METHODS

The anatomic relationship of the iliotibial tract (ITT) to the lateral recesses of the knee joint and the lateral femoral epicondyle was investigated with MR arthrography at full extension and at 30 degrees and 60 degrees of knee flexion in six cadaveric knees. Seventeen MR imaging studies in 16 patients with ITBFS were evaluated.

RESULTS

In the cadaveric study, no interference of the lateral synovial recess with the lateral femoral epicondyle at full extension and at 30 degrees and 60 degrees of knee flexion was observed. In all specimens, correlation of MR images with macroscopic and microscopic sections revealed no primary bursa between the lateral femoral epicondyle and the ITT. In clinical studies, MR imaging findings of poorly defined signal intensity abnormalities or circumscribed fluid collections were located in a compartmentlike space confined laterally by the ITT and medially by the meniscocapsular junction, the lateral collateral ligament, and the lateral femoral epicondyle.

CONCLUSION

MR imaging accurately depicts the compartmentlike distribution of signal intensity abnormalities in patients with ITBFS.

Ligaments and tendons of the ankle. Evaluation with low-field (0.2 T) MR imaging

PURPOSE

To investigate the value of MR imaging using a low-field imaging unit (0.2 T) for the evaluation of ligaments and tendons of the ankle.

MATERIAL AND METHODS

Twelve ankle specimens were studied using low-field MR imaging (0.2 T). The Achilles tendon, the tibialis posterior tendon, and the lateral collateral ligaments were evaluated for the presence of degenerative changes and partial and complete tears. Visibility and overall image quality were analyzed by qualitative evaluation.

RESULTS

Low-field MR images of the 24 tendons were interpreted as normal in 11 cases, showing degenerative changes in 9 cases and a partial tear in 1 case. Visualization was regarded as not sufficient for a diagnosis in 3 cases. Of the 36 ligaments, 14 were regarded as normal while degenerative changes were seen in 5 cases and a tear in 2 cases. In 13 cases, no diagnosis could be established, and in 2 cases only a probable diagnosis was established. The best overall quality was obtained with the use of T1 spin-echo (680/20/4) and T2 multi-echo (3000/40/1) images.

CONCLUSION

Optimized protocols for examination of the ankle using low-field MR imaging may allow evaluation of the Achilles and tibialis posterior tendons, but these protocols may not be as useful for diagnosing ligamentous changes.

Peripheral focal low signal intensity areas in the degenerated annulus fibrosus on T2-weighted fast spin echo MR images: correlation with macroscopic and microscopic findings in elderly cadavers

OBJECTIVE

To correlate the peripheral focal low signal intensity areas in the degenerated annulus fibrosus on T2-weighted fast spin echo MR images with the macroscopic and microscopic findings in cadavers derived from elderly subjects.

DESIGN

Twenty-eight intervertebral disks (16 lumbar and 12 cervical) derived from four nonembalmed cadavers were examined with T1-weighted spin echo and proton density-weighted and T2-weighted fast spin echo MR imaging. The signal intensities of the annulus fibrosus were evaluated on sagittal MR images and correlated with the findings on corresponding sagittal anatomic sections. The MR imaging-histologic correlation was then studied.

RESULTS

Peripheral focal low signal intensity areas and adjacent regions of high signal intensity were found in five lumbar intervertebral disks. Peripheral focal low signal intensity regions consisted of disorganized compact annular fibers, tiny fissures, and dense fibrosis. The high signal intensity regions, adjacent to the areas of low signal intensity, consisted of mucoid degeneration, tiny fissures, and chondroid metaplasia.

CONCLUSIONS

Awareness of the histologic findings in regions that reveal peripheral focal low signal intensity with adjacent regions of high signal intensity in the degenerated annulus fibrosus on T2-weighted images may facilitate effective interpretation of clinical MR images of the spine.

Articular cartilage in the knee: mapping of the physiologic parameters at MR imaging with a local gradient coil--preliminary results

The authors designed and constructed a local gradient coil that produces large gradients and short rise times and connects to their clinical system. In a cadaveric patellar cartilage specimen, the coil was used to acquire images of the physiologic parameters T1, T2, proton density, and apparent diffusion coefficient. Variations in these parameters were evident in regions of normal and abnormal cartilage.

Static state hemodynamic variables estimation model for the moving-actuator type total artificial heart. Part. I--cardiac output estimation

Cardiac output estimation is a very important study for the artificial heart. In this paper, we developed a cardiac output estimation model for the moving-actuator type total artificial heart (MA-TAH) that was developed at Seoul National University Hospital. The proposed model is simple and provides beat-by-beat mean cardiac output estimation. Moreover, it uses non-invasively acquired signals. Model parameters were adjusted with in vitro data by least mean square (LMS) algorithm. Results showed that the proposed scheme gives a mean estimation error of about 0.1 (l/min) for the given data. This ensures the suitability of the proposed model.

Tibiofibular syndesmosis: high-resolution MRI using a local gradient coil

PURPOSE

Our goal was to correlate high-resolution MR images of the tibiofibular syndesmosis with anatomic sections.

METHOD

MRI was performed inside a local gradient coil on six cadaveric feet taped in 10-20 degrees dorsiflexion and 40-50 degrees plantar flexion by using axial and coronal T1-weighted SE sequences. After imaging, the specimens were frozen and sectioned into 3-mm-thick slices along the MR planes. Images were correlated with the anatomic sections.

RESULTS

MRI depicted the anatomy of the tibiofibular syndesmosis and surrounding structures. With the foot taped in dorsiflexion, axial imaging provided optimum views of the anterior, posterior, interosseous, and transverse tibiofibular ligaments. Coronal images allowed visualization of the entire course of the anterior, posterior, and transverse tibiofibular ligaments. The multifascicular appearance of the anterior tibiofibular ligament was best visualized in coronal sections. With the foot taped in dorsiflexion or in plantar flexion, it was possible to distinguish the posterior tibiofibular ligament and transverse tibiofibular ligament from the posterior talofibular ligament in all specimens.

CONCLUSION

High-resolution MRI using a local gradient coil provides excellent delineation of the ligaments of the distal tibiofibular syndesmosis.

Vascular leiomyoma of an extremity: MR imaging-pathology correlation

OBJECTIVE

The objective of our study was to analyze MR images of vascular leiomyoma of the extremity and to compare these images with histopathologic findings to determine if a correlation exists.

CONCLUSION

T2-weighted MR images of vascular leiomyoma of an extremity showed a mass with mixed areas that were both hyper- and isointense to skeletal muscle and also revealed a hypointense rim; these images correlate with histopathologic findings of smooth muscle, vessels, fibrous tissue, an intravascular thrombus, and a fibrous capsule.

Evaluation of the anterior cruciate ligament of the knee: comparison between partial flexion true sagittal and extension sagittal oblique positions during MR imaging

OBJECTIVE

To compare partial flexion true sagittal (FS) magnetic resonance (MR) images with extension sagittal oblique (ESO) MR images with regard to delineation of the anterior cruciate ligament (ACL) in the knee.

DESIGN

To establish the appropriate degree of flexion of the knee joint, two human cadaveric knee joints were used as a supplementary technique. FS and ESO images then were performed in 17 knees with an intact ACL and six knees with a torn ACL. In 22 of the 23 knees in which the MR diagnosis of intact or torn ACL corresponded to that derived from arthroscopy, the paired MR images were rated by a three-point scale.

RESULTS

FS images were rated superior to ESO images in 53%, 41% and 47% of cases with regard to femoral attachment sites, midportions and tibial attachment sites of intact ACLs, respectively. FS images allowed better assessment of disrupted ACLs and residual ligamentous structures. Overall the FS images were either equal to or better than the ESO in the majority of cases.

CONCLUSION

FS images are useful when the ACL is not well visualized in initial ESO images.

Relationship between global cytosolic Ca2+ concentration and Ca2+-activated K+ current in rabbit cerebral arterial myocyte

In smooth muscle cells, the sarcoplasmic reticulum (SR) has been identified as the primary storage site for intracellular Ca2+. The peripheral SR is in close proximity with plasma membrane to make a narrow subsarcolemmal space. In this study, we investigated the regulation of subsarcolemmal [Ca2+] ([Ca2+]sl) and global cytosolic [Ca2+] ([Ca2+]c) of rabbit arterial smooth muscle using whole cell patch clamp technique and microspectrofluorimetry. The Ca2+-activated K+ current (IK(Ca)) and the ratio of fura-2 fluorescence (R340/380) were considered to reflect the [Ca2+]sl and [Ca2+]c, respectively. At a holding potential of 0 mV, extracellular application of 10 mM caffeine, a well known Ca2+-releasing agent, induced transient increase of IK(Ca) and R340/380 (IK(Ca)-transient and R340/380-transient, respectively). The increase and decay of IK(Ca) transient was faster than R340/380-transient. By repetitive application of caffeine, when the refilling state of SR was supposed to be lower than the control condition, IK(Ca)-transient and R340/380 transient were suppressed to different levels; e.g. the second application 20 sec after the first could induce smaller IK(Ca) transient than R340/380-transient. Dissociation of IK(Ca)-transient and R340/380-transient was removed by sufficient (>3 min) washout of caffeine. Recovery from the dissociation was also dependent upon the membrane potential; faster recovery was observed at negative (-40 mV) holding potential than at depolarized (0 mV) condition. Dissociation of IK(Ca) from [Ca2+]c was also partially prevented by perfusion with Na+-free (replaced by NMDG+) extracellular solution. These results suggest that, 1) there is prominent spatial inhomogeneity of [Ca2+] in cerebral arterial myocyte, 2) [Ca2+]Sl is preferentially affected by the interference from nearby plasmalemmal Ca2+ regulation mechanism which is partly dependent upon extracellular Na+.

Structure-function studies on positions 17, 18, and 21 replacement analogues of glucagon: the importance of charged residues and salt bridges in glucagon biological activity

We have designed and synthesized eight compounds 2-9 which incorporate various amino acid residues in positions 17, 18, and 21 of the glucagon molecule: 2, [Lys17]glucagon amide; 3, [Lys18]glucagon amide; 4, [Nle17,Lys18,Glu21]glucagon amide; 5, [Orn17,18, Glu21]glucagon amide; 6, [d-Arg17]glucagon; 7, [d-Arg18]glucagon; 8, [d-Phe17]glucagon; and 9, [d-Phe18]glucagon. Compared to glucagon (IC50 = 1.5 nM), analogues 2-9 were found to have binding affinity IC50 values (in nM) of 0.7, 4.1, 1.0, 2.0, 5.0, 25.0, 43.0, and 32.0, respectively. When these compounds were tested for their ability to stimulate adenylate cyclase (AC) activity, they were found to be full or partial agonists having maximum stimulation values of 100, 100, 100, 100, 87, 78, 94, and 100%, respectively. On the basis of the X-ray crystal structure of [Lys17,18,Glu21]glucagon amide reported here, the ability to form a salt bridge between Lys18 and Glu21 is probably key to their increased binding and second messenger activities. Among the eight analogues synthesized here, only analogue 4 preserves the ability to form a salt bridge between Lys18 and Glu21. However, since these modifications are minor they do not seem to change the amphiphilic character of the C-terminus, allowing these analogues to reach 78-100% stimulation in the adenylate cyclase assay. Biological data from analogues 6-9 supports the idea that position 18 of glucagon may influence binding only, while position 17 may influence both receptor recognition and transduction.

Evaluation of the triangular fibrocartilage and the scapholunate and lunotriquetral ligaments in cadavers with low-field-strength extremity-only magnet. Comparison of available imaging sequences and macroscopic findings

RATIONALE AND OBJECTIVES

The authors assessed the ability of a low-field-strength extremity-only magnet to provide visualization of the triangular fibrocartilage and the scapholunate and lunotriquetral ligaments.

METHODS

Twelve human wrists were examined with a 0.2 T extremity-only magnet. T1-weighted spin echo, proton density-weighted, and T2-weighted turbo spin echo, short-tau inversion recovery, and three-dimensional gradient recalled echo images were acquired, and sections of the specimens were then made that corresponded to the magnetic resonance images. Masked imaging analyses were correlated with macroscopic and limited histopathologic findings.

RESULTS

Low-field-strength extremity-only magnet allowed consistent visualization of the triangular fibrocartilage and accurate assessment of a small number of complete tears of the triangular fibrocartilage. The scapholunate ligaments in all cases were identified using a combination of imaging sequences. Consistent visualization of the lunotriquetral ligament with a low-field-strength extremity magnet was difficult.

CONCLUSIONS

Magnetic resonance imaging with a low-field-strength extremity-only magnet can be used to visualize the triangular fibrocartilage and the scapholunate ligament, but not the lunotriquetral ligament.

Evaluation of patellar cartilage in cadavers with a low-field-strength extremity-only magnet: comparison of MR imaging sequences, with macroscopic findings as the standard

PURPOSE

To assess a low-field-strength extremity-only magnet in the evaluation of patellar cartilage abnormalities.

MATERIALS AND METHODS

Four regions in each of 10 patellae from cadavers were examined in the transaxial plane with a 0.2-T extremity-only magnet and the following sequences: T1-weighted spin echo, proton density- and T2-weighted turbo spin echo, short inversion time inversion recovery, and two- and three-dimensional gradient echo with and without magnetization transfer contrast subtraction. Lesions depicted with MR imaging and seen in anatomic sections of the patellae were classified according to a modified standardized arthroscopic grading system. MR imaging and pathologic correlation was then analyzed.

RESULTS

On the basis of macroscopic findings, 14 of 40 cartilage regions were found to be intact, grade 2A lesions were present in eight regions, grade 2B lesions in eight, and grade 3 lesions in 10. For the various MR imaging techniques, sensitivity was 25%-62% for grade 2A lesions, 50%-75% for grade 2B lesions, and 60%-90% for grade 3 lesions. Specificity was 81%-97% for grades 2A and 2B lesions, and 80%-97% for grade 3 lesions. Accuracy was 75%-82% for grade 2A lesions, 75%-92% for grade 2B lesions, and 80%-92% for grade 3 lesions.

CONCLUSION

High-grade cartilaginous lesions can be evaluated reliably with low-field-strength MR imaging by using a combination of imaging sequences.

Exacerbated pain in cervical radiculopathy at axial rotation, flexion, extension, and coupled motions of the cervical spine: evaluation by kinematic magnetic resonance imaging

RATIONALE AND OBJECTIVES

The authors evaluate the functional changes in patients with cervical radiculopathy and increasing symptoms after provocative maneuvers at flexion, extension, axial rotation, and coupled motions of the cervical spine.

METHODS

Twenty-one patients with cervical disc herniation (n = 17) or cervical spondylosis (n = 4) in whom symptoms were elicited at flexion, extension, axial rotation, and coupled motions of the cervical spine were studied. The patients were examined inside a positioning device by using a circular surface coil for signal reception. At neutral position (0 degrees) and at provocative positions sagittal T2-weighted turbo spin-echo, axial T2-weighted two-dimensional flash sequence, sagittal three-dimensional (3D) fast imaging with steady state precision sequence and coronal 3D double-echo-in-the-steady-state sequences were obtained. The 3D sequences were reformatted in the axial and oblique coronal planes perpendicular to the exiting nerve roots. The images were evaluated for the size of disc herniations, the foraminal size and cervical cord rotation or displacement at provocative position compared with neutral position (0 degrees).

RESULTS

Compared with neutral position (0 degrees), change in size of disc herniation was not found in any (0%) of the provocative positions. In five (24%) patients cervical cord rotation or displacement was noted at axial rotation. The foraminal size increased at flexion, axial rotation to the opposite side of pain and flexion combined with axial rotation to the opposite side of the pain. The foraminal size decreased at extension combined with axial rotation to the side of the pain. A decrease or no change in foraminal size was observed at either extension or axial rotation to the side of the pain.

CONCLUSIONS

In patients with cervical disc herniation or cervical spondylosis, exacerbated pain at defined provocative maneuvers is related more to changes in the foraminal size and to nerve root motion with, in some cases, cervical cord rotation or displacement than to changes in the size of herniated discs.

Implantable control, telemetry, and solar energy system in the moving actuator type total artificial heart

The moving actuator type total artificial heart (TAH) developed in the Seoul National University has numerous design improvements based upon the digital signal processor (DSP). These improvements include the implantability of all electronics, an automatic control algorithm, and extension of the battery run-time in connection with an amorphous silicon solar system (SS). The implantable electronics consist of the motor drive, main processor, intelligent Li ion battery management (LIBM) based upon the DSP, telemetry system, and transcutaneous energy transmission (TET) system. Major changes in the implantable electronics include decreasing the temperature rise by over 21 degrees C on the motor drive, volume reduction (40 x 55 x 33 mm, 7 cell assembly) of the battery pack using a Li ion (3.6 V/cell, 900 mA.h), and improvement of the battery run-time (over 40 min) while providing the cardiac output (CO) of 5 L/min at 100 mm Hg afterload when the external battery for testing is connected with the SS (2.5 W, 192.192, 1 kg) for the external battery recharge or the partial TAH drive. The phase locked loop (PLL) based telemetry system was implemented to improve stability and the error correction DSP algorithm programmed to achieve high accuracy. A field focused light emitting diode (LED) was used to obtain low light scattering along the propagation path, similar to the optical property of the laser and miniature sized, mounted on the pancake type TET coils. The TET operating resonance frequency was self tuned in a range of 360 to 410 kHz to provide enough power even at high afterloads. An automatic cardiac output regulation algorithm was developed based on interventricular pressure analysis and carried out in several animal experiments successfully. All electronics have been evaluated in vitro and in vivo and prepared for implantation of the TAH. Substantial progress has been made in designing a completely implantable TAH at the preclinical stage.

Gamekeeper thumb: comparison of MR arthrography with conventional arthrography and MR imaging in cadavers

PURPOSE

To compare magnetic resonance (MR) arthrography with conventional arthrography and standard MR imaging in the evaluation of gamekeeper thumb.

MATERIALS AND METHODS

Eighteen cadaveric thumbs with (n = 12) or without (n = 6) experimental abduction stress were examined with conventional arthrography, standard MR imaging, and MR arthrography. Standard MR imaging and MR arthrography were performed with 0.2-T (low-field-strength) extremity-only and 1.5-T (high-field-strength) magnets. Results of blinded imaging analyses were correlated with pathologic findings. Paired MR images and MR arthrograms were rated with a three-point scale.

RESULTS

Fourteen ulnar collateral ligaments were torn, including eight nondisplaced (57%) and six displaced (43%) tears. For the presence of tear, diagnostic accuracy of conventional arthrography, low-field-strength MR imaging, high-field-strength MR imaging, low-field-strength MR arthrography, and high-field-strength MR arthrography was 83%, 89%, 90%, 94%, and 100%, respectively. With regard to displacement of the torn ligament, diagnostic accuracy was 61%, 89%, 90%, 94%, and 100%, respectively. MR arthrograms were rated superior to standard MR images in 72% and 90% of specimens with low-field-strength and high-field-strength magnets, respectively.

CONCLUSION

Of the tested methods, MR arthrography proved to be the most sensitive to the diagnosis of a torn ulnar collateral ligament of the first metacarpophalangeal joint and of displacement of the torn ligament.

Idiopathic pulmonary fibrosis vs. pulmonary involvement of collagen vascular disease: HRCT findings

The purpose of this study is to assess the differences of high-resolution CT (HRCT) findings in patients with idiopathic pulmonary fibrosis (IPF) and pulmonary involvement of collagen vascular disease (CVD). We analyzed the HRCT findings of 33 patients with IPF and 23 patients with CVD in terms of predominant pattern, site of involvement, mediastinal lymph node enlargement, pleural change, and pulmonary volume loss. The predominant HRCT pattern was honeycombing for IPF (58%), and ground-glass opacity for CVD (57%). Predominantly subpleural involvement was seen in 90% of IPF and 83% of CVD patients. Mediastinal lymph node enlargement was seen in 61% of the patients with IPF and 13% with CVD (p = 0.0004). Pleural thickening was seen in 97% of the patients with IPF and 35% with CVD and the severity of pleural thickening is statistically significant (p = 0.00001). Pleural effusion was seen in 6% of the patients with IPF and 26% with CVD (p = 0.0351). The hilar height ratio was more than 1.5 in 52% of the patients with IPF and 30% with CVD (p = 0.2620). Although HRCT findings of IPF and pulmonary involvement of CVD are similar and overlap considerably, but patients with IPF showed a tendency to more progressed fibrosis than patients with CVD.

A solar cell system for extension of battery run time in a moving actuator total artificial heart

An implantable total artificial heart (TAH) system has strong dependence upon the external battery performance for operation. Even under sophisticated battery management control, the usable external battery performance continues to decrease, which limits TAH performance. One of the ways to overcome this energy problem is to use a solar system (SS). An SS can provide electrical power for the partial TAH drive or battery recharge. This article presents a new concept for use of the solar cell for obtaining double external battery performance. To achieve it, numeric simulations were carried out to obtain the proper magnitude of solar parameters. In the TAH used, the battery power for a cardiac output of 4-6 L/min is approximately 17 W/20 min. From simulated results, the optimal power and voltage of the SS were found to be 7 W, Voc = 27 V in the case of the 24 V motor. Each solar cell includes Voc = 0.5 V, Isc = 37 mA/cm2, FF (fill factor) = 0.77, and efficiency = 10%. Based on the simulation, the effect of solar power capacity on battery run time was studied. With use of 6.5 W SS (W 304 x H 245 x D 16 mm, 1.1 kg), battery performance decreased in vitro from 100% (fully charged) to > 55% vs 0% in the conventional battery system after 20 min operation. However, it dropped to below 20% when using W SS (W 192 x H 192 x D 16 cm, 0.6 kg). The results showed doubled battery run time could be obtained compared with a system without the SS. It was concluded that the proposed SS can be put to practical use as a future energy source for a TAH.

Intelligent Li ion battery management based on a digital signal processor for a moving actuator total artificial heart

An intelligent Li Ion battery management (ILBM) system was developed based on a digital signal processor (DSP). Instead of using relatively complicated hardware charging control, a DSP algorithm was used, and favorable characteristics in volume, mass, and temperature increase of the implantable battery were achieved. In vitro tests were performed to evaluate the DSP based algorithm for Li Ion charging control (24 V dc motor input power 16 W, 5 L/min, 100 mmHg afterload). In this article, the first improvement was volume reduction using a Li Ion battery (3.6 V/Cell, 900 mA, seven cells: 25.2 V, 22.7 W). Its volume and mass were decreased by 40% and 50% respectively (40*55*75 mm, 189 g), compared to previously reported results, with total energy capacity increased by 110% (more than 60 min vs 25 min run time in the other battery). The second improvement includes the ILBM, which can control the performance detection for each unit cell and has a low temperature rise. The ILBM's unit cell energy detection was important because the low performance of one cell dropped to 50% of the total performance along with a 20% increase in surface temperature. All electronics for a transcutaneous energy transmission (TET), battery, and telemetry were finalized for hybridization and used for total artificial heat (TAH) implantation.

The role of phenylalanine at position 6 in glucagon's mechanism of biological action: multiple replacement analogues of glucagon

Extensive evidence gathered from structure-activity relationship analysis has identified and confirmed specific positions in the glucagon sequence that are important either for binding to its receptor or for signal transduction. Fifteen glucagon analogues have been designed and synthesized by incorporating structural changes in the N-terminal region of glucagon, in particular histidine-1, phenylalanine-6, and aspartic acid-9. This investigation was conducted to study the role of phenylalanine at position 6 on the glucagon mechanism of action. These glucagon analogues have been made by either deleting or substituting hydrophobic groups, hydrophilic groups, aromatic amino acids, or a D-phenylalanine residue at this position. The structures of the new analogues are as follows: [des-His1, des-Phe6, Glu9]glucagon-NH2 (1); [des-His1,Ala6,Glu9]glucagon-NH2 (2); [des-His1,Tyr6,Glu9]glucagon-NH2 (3); [des-His1,Trp6,Glu9]-glucagon-NH2 (4); [des-His1,D-Phe6,Glu9]glucagon-NH2 (5); [des-His1,Nle6,Glu9]glucagon-NH2 (6); [des-His1,Asp6,Glu9]glucagon-NH2 (7); [des-His1,des-Gly4,Glu9]glucagon-NH2 (8); [desPhe6,-Glu9]glucagon-NH2 (9); [des-Phe6]glucagon-NH2 (10); [des-His1, des-Phe6]glucagon-NH2 (11); [des-His1, des-Phe6,Glu9]glucagon (12); [des-Phe6,Glu9]glucagon (13); [des-Phe6]glucagon (14); and [des-His1, des-Phe6]glucagon (15). The receptor binding potencies IC50 values are 48 (1), 126 (2), 40 (3), 19 (4), 100 (5), 48 (6), 2000 (7), 52 (8), 113 (9), 512 (10), 128 (11), 1000 (12), 2000 (13), 500 (14), and 200 nM (15). All analogues were found to be antagonists unable to activate the adenylate cyclase system even at concentrations as high as 10(-5) M except for analogues 6 and 8, which were found to be weak partial agonists/partial antagonists with maximum stimulation between 6-12%. In competitive inhibition experiments, all the analogues caused a right shift of the glucagon-stimulated adenylate cyclase dose-response curve. The pA2 values were 8.20 (1), 6.40 (2), 6.20 (3), 6.25 (4), 6.30 (5), 6.30 (7), 6.05 (8), 6.20 (9), 6.30 (10), 6.25 (11), 6.10 (12), 6.20 (13), 6.20 (14), and 6.35 (15).

Synthesis of oligopeptide and peptidomimetic libraries

The elaboration of peptide libraries prepared by either chemical or biological methods in a format useful for discovery of peptides with specific biological activities was first introduced in the 1980s. A virtual explosion of activity in this area has occurred recently, and the basic approaches have been applied to a wide variety of chemistries and for all manner of biological, chemical and physical targets. Recent advances include new synthetic methodologies, new analytical methods, new design methods and new assay procedures.

Triton X-100 induces apoptosis in human hepatoma cell lines

The detergent Triton X-100 was used to establish a model for apoptosis in hepatoma cell lines. The electrophoresis of DNA extracted from 0.01% Triton X-100 treated hepatoma cell lines showed DNA ladder formation, a hallmark of apoptosis. The DNA fragmentation appeared within less than 60 min of the Triton X-100 treatment. Chromatin condensation and apoptotic bodies were observed by hematoxylin and eosin (H & E) stain, and fragmented nucleosome was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) test. Apoptosis was semi-quantitated by measuring the lactate dehydrogenase (LDH) level for cytotoxity. It was found that apoptosis had been induced in more than 90% of the cells treated with Triton X-100 for 150 min. These data show that Triton X-100 efficiently induces the apoptotic cell death in hepatoma cell lines.

Lung cancer in patients with idiopathic pulmonary fibrosis: CT findings

PURPOSE

The frequency of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) is higher than that of general population. To evaluate CT findings of lung cancer associated with IPF, we analyzed 32 patients with lung cancer associated with IPF.

METHOD

We analyzed retrospectively 32 patients with histologically confirmed lung cancer out of 244 consecutive cases diagnosed as IPF by either CT and clinical findings (n = 220) or histologically (n = 24). The patients were 40-85 years old (mean 66 years, M/F = 31/1). Scanning techniques were conventional CT in 24 patients, high-resolution CT (HRCT) in 2 patients, and both conventional CT and HRCT in 6 patients. We analyzed the CT patterns, locations, and histologic types of lung cancer.

RESULTS

The frequency of lung cancer in patients with IPF was 13.1% (32/244). In 17 of 32 patients, the CT findings of lung cancer were ill defined lesions mimicking air-space consolidation. Lung cancer was located mainly in the lower lobes (21/32) and peripheral portion (21/32). Histologically, squamous cell carcinoma was the most common type (18/32).

CONCLUSION

Typical CT findings of lung cancer were ill defined consolidation-like masses at the peripheral portion where the most advanced fibrosis was located.

Total artificial heart using neural and fuzzy controller

The aortic pressure (AoP) and pulmonary artery pressure (PAP) are important factors for the long-term survival of the patient receiving an implant of a total artificial heart (TAH). A new afterload regulation method using neural controllers has been developed for a moving actuator type TAH. Without any transducer, the proposed neural controller, based on the predetermined peak level of the motor current, regulates AoP by adjusting the actuator velocity. At the same time, a fuzzy controller based on expert knowledge prevents the PAP from being abnormally high. The proposed controller not only regulates the pump output on the maintenance of the normal AoP and PAP, but it also successfully controls the suction in the right heart. In vitro tests show that the proposed neural and fuzzy controllers effectively regulate AoP and PAP as well as prevent atrial suction.

Development of a precise controller for an electrohydraulic total artificial heart. Improvement of the motor's dynamic response

In an electrohydraulic total artificial heart developed at the National Cardiovascular Center (Osaka, Japan), two blood pumps are pushed alternatively by means of the bidirectional motion of a brushless DC motor for pump systole and diastole. Improvement in the dynamic response of the motor is very important to obtain better pump performance; this was accomplished by using power electronic simulation. For the motor to have the desired dynamic response, it must be commutated properly and the damping ratio (zeta), which represents transient characteristics of the motor, must lie between 0.4 and 0.8. Consequently, all satisfactory specifications with respect to power consumption must be obtained. Based on the simulated results, the design criteria were determined and the precise controller designed to reduce torque ripple and motor vibration, and determine motor stop time at every direction change. In in vitro tests, evaluation of the controller and dynamic response of the motor was justified in terms of zeta, power consumption, and motor stop time. The results indicated that the power consumption of the controller and the input power of the motor were decreased by 1.2 and 2.5 W at zeta = 0.6, respectively, compared to the previous system. An acceptable dynamic response of the motor, necessary for the reduction of torque ripple and motor vibration, was obtained between zeta = 0.5 and zeta = 0.7, with an increase in system efficiency from 10% to 12%. The motor stop time required for stable motor reoperation was determined to be over 10 msec, for a savings in power consumption of approximately 1.5 W. Therefore, the improved dynamic response of the motor can contribute to the stability and reliability of the pump.

Importance of metabolic function of the natural lung evaluated by prolonged exclusion of the pulmonary circulation

It is generally considered that the natural lung metabolizes various vasoactive substances through the pulmonary circulation. However, the influences of bypassing or eliminating the pulmonary circulation have not been fully elucidated, especially for prolonged periods. In this study, we performed total cardiopulmonary bypass and exclusion of the pulmonary circulation for up to 336 hr in awake goats to clarify the importance of the metabolic function of the lung. In seven adult goats, biventricular bypass with a pulsatile ventricular assist system was first established. After 2 weeks, the biventricular bypass was converted to total cardiopulmonary bypass without anesthesia. Adequate gas exchange and perfusion support were achieved in all animals. However, the institution of total cardiopulmonary bypass led to marked decreases in the mean aortic pressure and systemic vascular resistance, and they remained low thereafter. The arterial levels of prostaglandin E2 and norepinephrine, which are inactivated naturally through the pulmonary circulation, increased remarkably. These results indicate that the natural lung plays an important role in controlling systemic circulation by metabolizing various vasoactive substances. Understanding the non respiratory function of the natural lung is of prime importance for advancement of lung and heart-lung support.