Endoscopic management of malignant biliary obstruction by means of covered metallic stents: primary stent placement vs. re-intervention.

BACKGROUND AND STUDY AIMS: Recent progress in chemotherapy has prolonged the survival of patients with malignant biliary strictures, leading to increased rates of stent occlusion. Occlusion of covered metallic stents now occurs in about half of all patients with malignant biliary strictures. The removal of metallic stents followed by placement of a second stent has been attempted, but outcomes remain controversial. The aim of the current study was to evaluate the effectiveness and safety of the primary placement and secondary placement (re-intervention) of covered metallic stents and to assess the feasibility and safety of stent removal. PATIENTS AND METHODS: The study included 186 patients with unresectable malignant biliary strictures who underwent primary stent placement between October 2001 and March 2010.  Covered biliary self-expandable metal stents (SEMSs) were removed in 39 of these patients, and 36 underwent re-intervention. The patency times, occlusion rates of the first stent and re-intervention, success rates of stent removal, and complications were investigated. RESULTS: Covered SEMSs were placed in 186 patients. The median patency time of the first stent was 352 days. Stent occlusion occurred in 48.9 % of the patients and was mainly caused by debris or food residue (37 %), dislocation (19 %), and migration with hyperplasia (19 %). Stent removal was attempted in 50 patients and was successful without complication in 39 (78 %). Most of the patients in whom stent removal was unsuccessful had migration with hyperplasia. The median patency time of the second stent was 263 days. The stent patency time did not significantly differ between the first and the second stent. CONCLUSIONS: Covered SEMSs could be safely removed at the time of stent occlusion. Patency rates were similar for initial stent placement and re-intervention.

Fine needle aspiration using forward-viewing endoscopic ultrasonography.

BACKGROUND AND STUDY AIM: A prototype forward-viewing instrument has been developed for therapeutic endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA). We had the opportunity to use this forward-viewing echo endoscope and to study its clinical usefulness, mainly for diagnostic EUS-FNA. PATIENTS AND METHODS: The prototype forward-viewing echo endoscope was used for 15 months between November 2006 and March 2010, in a study group comprising 47 consecutive patients. Diagnostic EUS-FNA was done in 38 patients and the diagnostic accuracy of the forward-viewing device was compared with that from an oblique-viewing echo endoscope in reference patients who were matched by disease and puncture route. Therapeutic EUS was done in nine patients (pseudocyst drainage in six; celiac ganglia neurolysis, biliary drainage, and pancreatic duct drainage in one each). RESULTS: Diagnostic EUS-FNA provided a correct diagnosis in 97.4 % (37/38 patients), which was not significantly different from the 94.7 % (36/38) in the reference patients. Lesions considered difficult to access with an oblique-viewing scope, such as those located at the fornix, or the head of the pancreas, or associated with strictures, were easily punctured, as were those located at the body or tail of the pancreas or at the porta hepatis. Treatment was successful in all nine patients who underwent therapeutic EUS procedures. None of the 47 patients had any complications. CONCLUSIONS: A forward-viewing echo endoscope that allows target sites to be punctured more perpendicularly with minimal effort, can be used for diagnostic EUS-FNA and this may be advantageous, depending on the site of target lesions.

Medial meniscus posterior root tear induces pathological posterior extrusion of the meniscus in the knee-flexed position: An open magnetic resonance imaging analysis.

BACKGROUND: A medial meniscus posterior root tear (MMPRT) is defined as an injury to the posterior meniscal insertion on the tibia. In MMPRT, the medial meniscus (MM) hoop function is damaged, and the MM undergoes a medial extrusion into the interior from the superior articular surface of the tibia. However, the details of MM position and movement during knee joint movement are unclear in MMPRT cases. The present study aims to evaluate MM position and movement via magnetic resonance imaging (MRI) examination of the MM posterior extrusion (MMPE) at knee flexion angles of 10° and 90°. We hypothesized that, during knee flexion, the MM will shift to the posterior and the posterior extrusion will increase compared to that when the knee is extended. MATERIALS AND METHODS: Twenty-four patients were diagnosed with symptomatic MMPRT on open MRI examination. Preoperative MMPE, anteroposterior interval (API) of the MM, and MM medial extrusion (MMME) at knee flexion angles of 10° and 90° were measured. RESULTS: For patients with MMPRT, the MMPE increased from -4.77±1.43mm to 3.79±1.17mm (p<0.001) when the knee flexion angle increased from 10° to 90°. Further, flexing the knee from 10° to 90° decreased the API of the MM from 20.19±4.22mm to 16.41±5.14mm (p<0.001). MMME showed no significant change between knee flexion angles of 10° and 90°. DISCUSSION: This study demonstrated that, in cases of MMPRT, the MMPE clearly increases when the knee is flexed to 90°, while MMME does not change. Our results suggest that open MRI examination can be used to evaluate the dynamic position of the posterior MM by scanning the knee as it flexes to 90°. LEVEL OF EVIDENCE: IV: retrospective cohort study.

Defect in biosynthesis of mitochondrial acetoacetyl-coenzyme A thiolase in cultured fibroblasts from a boy with 3-ketothiolase deficiency.

The etiology of 3-ketothiolase deficiency has been attributed to a defect of mitochondrial acetoacetyl-CoA thiolase because the acetoacetyl-CoA thiolase activity in related materials is not activated by K+, a property characteristic for this enzyme. We studied the enzyme protein and the biosynthesis of mitochondrial acetoacetyl-CoA thiolase, using cultured skin fibroblasts from a 5-yr-old boy with 3-ketothiolase deficiency. The following results were obtained. (a) Activation of acetoacetyl-CoA thiolase activity by K+ was nil; (b) The enzyme activity was not affected by treatment with the antibody against mitochondrial acetoacetyl-CoA thiolase; (c) A signal for mitochondrial acetoacetyl-CoA thiolase protein was not detected in the immunoblot analysis; and (d) Pulse-chase experiments of skin fibroblasts, using [35S]methionine, revealed no incorporation of radioactivity into this enzyme. Therefore, fibroblasts from this patient lacked mitochondrial acetoacetyl-CoA thiolase protein due to a defect in its biosynthesis.

Peroxisome targeting signal of rat liver acyl-coenzyme A oxidase resides at the carboxy terminus.

To identify the topogenic signal of peroxisomal acyl-coenzyme A oxidase (AOX) of rat liver, we carried out in vitro import experiments with mutant polypeptides of the enzyme. Full-length AOX and polypeptides that were truncated at the N-terminal region were efficiently imported into peroxisomes, as determined by resistance to externally added proteinase K. Polypeptides carrying internal deletions in the C-terminal region exhibited much lower import activities. Polypeptides that were truncated or mutated at the extreme C terminus were totally import negative. When the five amino acid residues at the extreme C terminus were attached to some of the import-negative polypeptides, the import activities were rescued. Moreover, the C-terminal 199 and 70 amino acid residues of AOX directed fusion proteins with two bacterial enzymes to peroxisomes. These results are interpreted to mean that the peroxisome targeting signal of AOX residues at the C terminus and the five or fewer residues at the extreme terminus have an obligatory function in targeting. The C-terminal internal region also has an important role for efficient import, possibly through a conformational effect.

A new aiming guide can create the tibial tunnel at favorable position in transtibial pullout repair for the medial meniscus posterior root tear.

INTRODUCTION: Injuries to the medial meniscus (MM) posterior root lead to accelerated cartilage degeneration of the knee. An anatomic placement of the MM posterior root attachment is considered to be critical in transtibial pullout repair of the medial meniscus posterior root tear (MMPRT). However, tibial tunnel creation at the anatomic attachment of the MM posterior root is technically difficult using a conventional aiming device. The aim of this study was to compare two aiming guides. We hypothesized that a newly-developed guide, specifically designed, creates the tibial tunnel at an adequate position rather than a conventional device. MATERIALS AND METHODS: Twenty-six patients underwent transtibial pullout repairs. Tibial tunnel creation was performed using the Multi-use guide (8 cases) or the PRT guide that had a narrow twisting/curving shape (18 cases). Three-dimensional computed tomography images of the tibial surface were evaluated using the Tsukada's measurement method postoperatively. Expected anatomic center of the MM posterior root attachment and tibial tunnel center were evaluated using the percentage-based posterolateral location on the tibial surface. Percentage distance between anatomic center and tunnel center was calculated. RESULTS: Anatomic center of the MM posterior root footprint located at a position of 78.5% posterior and 39.4% lateral. Both tunnels were anteromedial but tibial tunnel center located at a more favorable position in the PRT group: percentage distance was significantly smaller in the PRT guide group (8.7%) than in the Multi-use guide group (13.1%). DISCUSSION: The PRT guide may have great advantage to achieve a more anatomic location of the tibial tunnel in MMPRT pullout repair. LEVEL OF EVIDENCE: III.

Pullout repair of a medial meniscus posterior root tear using a FasT-Fix® all-inside suture technique.

A medial meniscus posterior root tear (MMPRT) may increase the tibiofemoral contact pressure by decreasing the tibiofemoral contact area. Meniscal dysfunction induced by posterior root injury may lead to the development of osteoarthritic knees. Repair of a MMPRT can restore medial meniscus (MM) function and prevent knee osteoarthritis progression. Several surgical procedures have been reported for treating a MMPRT. However, these procedures are associated with several technical difficulties. Here, we describe a technique to stabilize a torn MM posterior root using the FasT-Fix® all-inside meniscal suture device and a new aiming device. The uncut free-end of the FasT-Fix® suture can be used as a thread for transtibial pullout repair. Our procedure might help overcome the technical difficulties in arthroscopic treatment of a MMPRT.

Reduction of beta-oxidation capacity of rat liver mitochondria by feeding orotic acid.

Rats were maintained on fat-free high carbohydrate diets either with or without orotic acid (1%, w/w), pantethine (1%, w/w), adenine (0.25%, w/w), and/or p-chlorophenoxyisobutyrate (0.25%, w/w). Oxidation of fatty acid by liver mitochondria was inhibited to less than half that of the control after administration of orotic acid. Activities of acyl-CoA dehydrogenases were markedly decreased by orotic acid administration, but the following enzyme activities were not, or only slightly decreased: acyl-CoA synthetase, carnitine acyltransferases, enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase and 3-ketoacyl-CoA thiolase. Simultaneous addition of pantethine in the orotic acid-containing diet prevented induction of fatty liver. It also prevented decreases in fatty acid oxidation capacity and acyl-CoA dehydrogenase activity. Introduction of adenine or p-chlorophenoxyisobutyrate, which reverse orotic acid-induced fatty liver, reversed oxidation and acyl-CoA dehydrogenase activities to control levels. The oxidation capacity of the peroxisomal system remained unchanged after administration of orotic acid.

Turnover of enzymes of peroxisomal beta-oxidation in rat liver.

Male Wistar rats were given a diet containing 2% (w/w) di-ethylhexyl)-phthalate (DEHP), a peroxisomal proliferator, for 4 weeks. The activities of enzymes of peroxisomal beta-oxidation and of catalase were markedly increased by the DEHP administration. The time required to reach halfway to the maximal induction for enzymes of peroxisomal beta-oxidation was 5--7 days, whereas that for catalase was 3 days. A separate DEHP group was placed on the control diet after 14 days of feeding with the DEHP diet. On the withdrawal of DEHP, activities of enzymes of the beta-oxidation system and of catalase decreased to the control levels with a half-life of 2--3 days. Responses of some mitochondrial enzymes involved in fatty acid oxidation are also described.

Cloning and expression of cDNA for a newly identified isozyme of bovine liver 3-hydroxyacyl-CoA dehydrogenase and its import into mitochondria.

cDNA for a heretofore undescribed mitochondrial 3-hydroxyacyl-CoA dehydrogenase, designated as the type II enzyme with different molecular and catalytic properties, compared to those of the classical mitochondrial beta-oxidation enzyme (type I enzyme), was cloned from a bovine liver cDNA library. Nucleotide sequence of the cDNA encoded 261 amino acids with a subunit molecular weight of 27,140. The deduced primary structure of the type II enzyme showed no significant homology to the reported amino acid sequence of the classical 3-hydroxyacyl-CoA dehydrogenases. On SDS-PAGE, no differences in subunit molecular weights were observed among the in vitro translation products, the recombinant type II enzyme produced in Escherichia coli and the purified enzyme. NH2-terminal and COOH-terminal amino acid sequence analysis of the purified type II enzyme revealed that the mature enzyme had not been proteolytically processed. The in vitro translation products of the type II enzyme were efficiently incorporated into isolated rat liver mitochondria, without changes in size, thereby suggesting that unlike other mitochondrial enzymes of fatty acid beta-oxidation, the type II enzyme had no cleavable signal peptide upon import into mitochondria.

Effect of triamcinolone administration on content of flavins in rabbit liver.

Triamcinoline acetonide (10 mg per kg of body weight a day) was administered to rabbit fed on a laboratory chow diet. The content of flavins in liver but not in kidney, muscle and brain started to decrease 24 h after a single dose. The activities of enzymes in the liver were determined: the activities of pyruvate dehydrogenase complex, lipoamide dehydrogenase (NADH:lipoamide oxidoreductase EC 1.6.4.3), NADH dehydrogenase (NADH : (acceptor) oxidoreductase EC 1.6.99.3) and D-amino acid oxidase (D-amino acid: oxygen oxidoreductase (deaminating) EC 1.4.3.3) were decreased but those of succinate dehydrogenase (succinate : (acceptor) oxidoreductase EC 1.3.99.1) and xanthine oxidase (xanthine : oxygen oxidoreductase EC 1.2.3.2) remained unchanged. The activities of enzymes in the kidney, however, remained unchanged except the decrease in the activity of pyruvate dehydrogenase complex.

Residue-residue potentials with a favorable contact pair term and an unfavorable high packing density term, for simulation and threading.

Attractive inter-residue contact energies for proteins have been re-evaluated with the same assumptions and approximations used originally by us in 1985, but with a significantly larger set of protein crystal structures. An additional repulsive packing energy term, operative at higher densities to prevent overpacking, has also been estimated for all 20 amino acids as a function of the number of contacting residues, based on their observed distributions. The two terms of opposite sign are intended to be used together to provide an estimate of the overall energies of inter-residue interactions in simplified proteins without atomic details. To overcome the problem of how to utilize the many homologous proteins in the Protein Data Bank, a new scheme has been devised to assign different weights to each protein, based on similarities among amino acid sequences. A total of 1168 protein structures containing 1661 subunit sequences are actually used here. After the sequence weights have been applied, these correspond to an effective number of residue-residue contacts of 113,914, or about six times more than were used in the old analysis. Remarkably, the new attractive contact energies are nearly identical to the old ones, except for those with Leu and the rarer amino acids Trp and Met. The largest change found for Leu is surprising. The estimates of hydrophobicity from the contact energies for non-polar side-chains agree well with the experimental values. In an application of these contact energies, the sequences of 88 structurally distinct proteins in the Protein Data Bank are threaded at all possible positions without gaps into 189 different folds of proteins whose sequences differ from each other by at least 35% sequence identity. The native structures for 73 of 88 proteins, excluding 15 exceptional proteins such as membrane proteins, are all demonstrated to have the lowest alignment energies.

The figure-of-nine leg position for anatomic anterior cruciate ligament reconstruction.

Anatomic double-bundle anterior cruciate ligament (ACL) reconstruction can restore the function and kinematics of the knee in ACL-deficient patients. Several outside-in drilling systems for accurate femoral tunnel creations have been developed. However, the femoral tunnel creation at the lower position of the intercondylar notch can be difficult in a usual leg position with the knee flexed at 90° without varus stress. This technical note describes that the figure-of-nine leg position provides a better arthroscopic view to safely clean up the ACL femoral footprint located at the lower area of the lateral intercondylar wall. This position is useful to create the optimal femoral tunnels using the outside-in drilling technique, without damaging the lateral meniscus posterior root, lateral tibial eminence, and supplemental fibers that bridge the gap between the lateral meniscus and the ACL tibial insertion.

Ruptured aneurysm of aortic sinus of Valsalva into right ventricle.

We report a patient with ruptured aneurysm of the aortic sinus of Valsalva into the right ventricle, whose heart murmur represented only a diastolic element without aortic regurgitation. Surgery revealed a small opening through myocardium of the ventricular septum without ventricular septal defect. During systole, the opening was constricted and presumably closed with myocardial contraction, and left-to-right shunt might have occurred only in diastole. This might lead to only a diastolic murmur.

Biosynthesis of carnitine octanoyltransferase and carnitine palmitoyltransferase.

Male Wistar rats were fed a diet with or without di(2-ethylhexyl)phthalate (DEHP) for 2 weeks. Carnitine octanoyltransferase (COT) in the liver was increased 23.5-fold in rats given DEHP. It was found by in vivo experiments using L-[4,5-3H]leucine and the immunoprecipitation technique that the rate of synthesis of COT was 14.1-fold higher and that of its degradation was 1.5-fold lower in the DEHP group. COT was translated much more effectively in free polysomes than in membrane-bound polysomes. The molecular size of the in vitro product was the same as that of the mature enzyme. The translation activity of mRNA coding for COT measured with total hepatic RNA was 16.6-fold higher in the DEHP group. Carnitine palmitoyltransferase (CPT) was increased 5.9-fold after administration of DEHP. The rate of synthesis of CPT measured in the in vivo experiment was 5.0-fold higher in the DEHP group. The rate of its degradation was the same in the two groups. CPT was also translated much more effectively in free polysomes. The size of the preenzyme was larger than that of the subunit of the mature enzyme by about 2,400 daltons. In contrast to COT, the increase in the translation activity of mRNA for CPT by administration of DEHP was markedly higher than the increase in the rate of its synthesis measured in the in vivo experiment.

Effects of di-(2-ethylhexyl)phthalate administration on carbohydrate and fatty acid metabolism in rat liver.

1. Rats were fed on a diet containing 0, 1, 2, or 4% di-(2-ethylhexyl)phthalate (DEHP), a widely used plasticizer, for four weeks. 2. The level of plasma triglyceride was decreased in both the 1% DEHP and the 2% DEHP groups maintained for 1 to 2 weeks, but that of cholesterol was not changed. Plasma free fatty acid and ketone bodies increased in all DEHP groups. 3. The level of blood glucose was depressed to about 80% in the 2% and the 4% DEHP groups. Liver glycogen decreased markedly. Isotopic incorporations of 14C from [2-14C]pyruvate into blood glucose and liver glycogen were decreased. The changes in the contents of intermediates in the liver indicate that gluconeogenesis is inhibited at the reaction(s) between 3-phosphoglycerate and fructose 1,6-diphosphate. 4. Hepatic fatty acid synthesis increased about 2-fold on DEHP administration. The content of phospholipid in the liver was increased, whereas that of triglyceride was decreased. The rate of phospholipid synthesis was increased, but that of triglyceride was not changed.

Purification and properties of rat liver acyl-CoA dehydrogenases and electron transfer flavoprotein.

Three acyl-CoA dehydrogenases and electron transfer flavoprotein, which catalyze the initial step of mitochondrial fatty acid beta-oxidation, were purified from livers of rats fed a diet containing di(2-ethylhexyl)phthalate. Three acyl-CoA dehydrogenases, classified into short chain, general, and long chain acyl-CoA dehydrogenases on the basis of their substrate specificities, each consisted of four subunits of identical size: the molecular weights of the native enzymes were 169,000 for short chain acyl-CoA dehydrogenase, 182,000 for general acyl-CoA dehydrogenase, and 168,000 for long chain acyl-CoA dehydrogenase. Electron transfer flavoprotein with a molecular weight of 57,000 consisted of heterogeneous subunits with molecular weight of 33,500 and 25,100. The catalytic properties and molecular structures of rat liver acyl-CoA dehydrogenases were similar to those of the enzymes purified from other mammalian tissues such as pig heart, pig liver, and beef kidney. We could not obtain purified preparations of the three acyl-CoA dehydrogenases from livers of the control rats although the three dehydrogenases were completely separated from each other. The enzymes from the control and the di(2-ethylhexyl)phthalate-treated rats were compared and no differences were found in molecular sizes of the native enzymes and of their subunits, substrate specificities and immunochemical reactivities.

Induction of acyl-CoA dehydrogenases and electron transfer flavoprotein and their roles in fatty acid oxidation in rat liver mitochondria.

The capacity of mitochondrial beta-oxidation and activities of three acyl-CoA dehydrogenases and electron transfer flavoprotein in rat liver were increased after administration of peroxisome proliferators such as di(2-ethylhexyl)phthalate or p-chlorophenoxyisobutyrate. Oxygen consumption by mitochondrial beta-oxidation with palmitate, palmitoyl-CoA or palmitoylcarnitine was in the range of 0.27-0.41 mumol O2/min per g liver and the dehydrogenase activity with palmitoyl-CoA was 0.56 mumol/min per g liver. These activities were increased, after administration of peroxisome proliferators, to 0.80-1.23 mumol O2/min per g liver and 1.06-1.08 mumol/min per g liver, respectively. The time required to reach half-maximal induction of the three acyl-CoA dehydrogenases and electron transfer flavoprotein after administration of di(2-ethylhexyl)phthalate was about 5 days. On the withdrawal of the agent, the activities of these flavoproteins decreased to the control levels with half-lives of about a day.

Identity of long-chain acyl-coenzyme A synthetase of microsomes, mitochondria, and peroxisomes in rat liver.

The identity of long-chain acyl-CoA synthetase in microsomes, mitochondria, and peroxisomes of rat liver was examined by using the antibody raised against a purified preparation of the microsomal enzyme. The enzyme activities of these three organelles and the purified microsomal enzyme were titrated by the antibody in a very similar fashion when the activity was measured in terms of palmitoyl-CoA synthetase activity. It was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the immunoprecipitates and by Western blot analysis that the enzymes of all three organelles consisted of a polypeptide with the same molecular weight as that of the purified enzyme, and that the specific enzyme activity of the antigenic protein in all three subcellular compartments was nearly the same. The presence of other palmitoyl-CoA synthetase activity in these organelles could not be confirmed. Immunocytochemical study to locate the antigenic site with protein A-gold complex showed that the gold particles were closely associated with the membranes of these organelles. The cell-free translation product in a rabbit reticulocyte lysate protein-synthesizing system and the subunit of the mature enzyme labeled with [35S]methionine in the liver slices exhibited the same mobility as the subunit of the purified enzyme on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme in microsomes, mitochondria, and peroxisomes was labeled at nearly the same rate when the liver slices were incubated with [35S]methionine.

Biosynthesis of enzymes of peroxisomal beta-oxidation.

Male Wistar rats were fed a diet with or without di(2-ethylhexyl)phthalate (DEHP), a peroxisome proliferator, for 2 weeks. The increases in the individual enzymes of the hepatic peroxisomal beta-oxidation system after administration of DEHP were 31- to 33-fold. It was found by in vivo experiments using L-[4,5-3H]leucine and the immunoprecipitation technique that the rates of synthesis of the enzymes were 16- to 20-fold higher and those of degradation were 1.7- to 1.9-fold lower in the DEHP group. The translation rates of these enzymes in vitro with liver RNA in the reticulocyte-lysate system were 12- to 14-fold higher in the DEHP group. Short-term kinetic labeling experiments on acyl-CoA oxidase consisting of three subunits were conducted in vivo to explore the biogenesis of peroxisomes. The label was found in the biggest subunit of the enzyme in the supernatant fraction shortly after the label injection, but was distributed to the smaller subunits later. The labeling in the smaller subunits in the peroxisomal fraction was greater than that of the supernatant. The distribution of the label among the subunits in these subcellular fractions was the same as that of the protein amounts 1 day after the label injection. This paper reports that the increase in the quantities of peroxisomal enzymes upon administration of DEHP is mainly due to the increase in their synthesis rates caused by the increase in amounts of mRNA coding for these enzymes.