Noninvasive multislice CT angiography in pediatric liver transplantation: a novel application.
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Child↗
Biomedical subjects
T Y Chen
Publications and source records attributed to T Y Chen.
Structural influence of hanatoxin binding on the carboxyl terminus of S3 segment in voltage-gated K(+)-channel Kv2.1.
The voltage-sensing domains of voltage-gated potassium channels Kv2.1 (drk1) contain four transmembrane segments in each subunit, termed S1 to S4. While S4 is known as the voltage sensor, the carboxyl terminus of S3 (S3C) bears a gradually broader interest concerning the site for gating modifier toxins like hanatoxin and thus the secondary structure arrangement as well as its surrounding environment. To further examine the putative three-dimensional (3-D) structure of S3C and to illustrate the residues required for hanatoxin binding (which may, in turn, show the influence on the S4 in terms of changes in channel gating), molecular simulations and dockings were performed. These were based on the solution structure of hanatoxin and the structural information from lysine-scanning results for S3C fragment. Our data suggest that several basic and acidic residues of hanatoxin are electrostatically and stereochemically mapped onto their partner residues on S3C helix, whereas some aromatic or hydrophobic residues located on the same helical fragment interact with the hydrophobic patch of the toxin upon binding. Therefore, a slight distortion of the S3C helix, in a direction toward the N-terminus of S4, may exist. Such conformational change of S3C upon toxin binding is presented as a possible explanation for the observed shift in hanatoxin binding-induced gating.
Animals↗
Formation study and X-ray structures of dinuclear beta-diketonate copper(I) complexes with conjugated ene-yne Lewis base. Implications for the use of (hfac)Cu(MHY) as a precursor for copper CVD.
Dinuclear [(hfac)Cu](2)(MHY) and [(hfac)Cu](2)(HY) species, where hfac = hexafluoroacetylacetonate, MHY = 2-methyl-1-hexen-3-yne, and HY = hex-3-yn-1-ene), are formed during copper chemical vapor deposition experiments when a bubbler containing the corresponding mononuclear species is used. These compounds and the so far unknown (hfac)Cu(HY) have been characterized by (1)H and (13)C NMR and IR spectroscopy and the two dinuclear species by X-ray crystallography and elemental analysis. As expected, in the structure of the dinuclear species, two roughly perpendicular Cu(hfac) moieties are bound to a single ene-yne: one to the C[triple bond]C, the other to the conjuguated double bond. Weak intra- and intermolecular Cu...Cu interactions have been detected in the solid. [(hfac)Cu](2)(HY) is more stable and more easily formed than [(hfac)Cu](2)(MHY) because of the hindrance character of the additional methyl groups. The formation of the dinuclear species from the mononuclear species is reversible as it has been demonstrated by (1)H NMR. The mononuclear species can be recovered from the dinuclear species when free ene-yne base is added. Crystallographic data for [(hfac)Cu](2)(MHY): C(17)H(12)O(4)F(12)Cu(2), triclinic, P1 (No. 2), Z = 4; at 298 K, a = 11.112(3) A, b = 13.472(4) A, c = 15.747(3) A, alpha = 94.95(2) degrees, beta = 98.15(2) degrees, gamma = 100.27(2) degrees; Crystallographic data for [(hfac)Cu](2)(HY): C(16)H(10)O(4)F(12)Cu(2), orthorhombic, Cc2a (No. 41, Aba2), Z = 8; at 230 K, a = 12.280(3) A, b = 13.531(3) A, c = 25.461(5) A.
Journal Article↗
Single imaging modality evaluation of living donors in liver transplantation: magnetic resonance imaging.
BACKGROUND: Liver graft size, anatomy of the bile duct and the vascular inflow and outflow are essential for living related liver transplantation (LRLT). Preoperative delineation of those variations that would change the operative procedure to achieve a successful result especially in an emergency condition. PURPOSE: Our aim was to develop a rapid and noninvasive imaging diagnostic method for the detection of anatomical variants that is mandatory for a safe operation when selecting potential liver transplant living donors. We used a different magnetic resonance (MR) imaging technique, which enabled to us to exploit the anatomical landmark of the liver, signal enhancement of blood flow in the abdomen, and the intrahepatic biliary routes inside the liver. Then, with the help of Advantage Window workstation reconstruction, the reconstructed single vascular or biliary systems were displaced in a three-dimensional fashion and the whole examination finished within 30 min. METHODS: Modification of the standard MR technique was performed on a superconductive 1.5T whole body image scanner, MR arteriogaphy, venography, and cholangiography with three-dimensional reconstruction in evaluating the anatomy of the hepatic arteries, hepatic veins, portal venous system, bile ducts, and liver size in potential liver transplant living donors. These anatomical structures were compared with traditional imaging methods. RESULTS: In all 38 cases, as well as delineation of the portal vein detail to the segmental level was satisfactorily obtained in this MR study. The images were well displayed in a three-dimensional fashion, which had good correlation with images from traditional imaging modalities and operative findings. In 86.8% cases, the MR arteriography was well matched with the celiac angiography. Of those 17 operative cases, estimation of liver volume was well correlated with the liver graft within 3.9-12.5% variation. In the major hepatic vein, we obtained 100% accuracy and 88.2% in the minor branches. Of 12 donors received intraoperative cholangiography during liver donation, good correlation of biliary anatomy was achieved. One donor was excluded from graft donation due to the complicated arterial supply to the left liver. According to the anatomical variation, surgical procedures in graft harvesting and anastomosis were readjusted and no major complications were found in those donors and all recipients survived after liver transplantation. CONCLUSION: MR volumetry, venography, angiography, and cholangiography with three-dimensional reconstruction is sufficient for all major imaging evaluation. It may replace the traditional conventional catheter angiography, computed tomography, sonography and endoscopic retrograde cholangiography as a single investigation in the evaluation of the potential liver transplant donors. Angiography is only valuable in suboptimal cases and intraoperative cholangiography is only performed in biliary ductile variants.
Adult↗
Sol-gel derived nitric-oxide releasing materials that reduce bacterial adhesion.
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Adhesins, Bacterial↗
Assessment of donor fatty livers for liver transplantation.
AIM: The effect of fatty liver on graft survival, especially with reference to macrovesicular and microvesicular steatosis, is still uncertain. This preliminarily study was designed to create a noninvasive method for the quantification of the hepatic fat content in vivo and to establish provisional criteria for the assessment of fatty donor livers before liver transplantation among transplant surgeons, radiologists, and pathologists. METHODS AND MATERIALS: Different degrees of rat fatty liver model were established by feeding rats a diet deficient in choline and methionine for different periods of time. Computed tomography (CT) with test tubes containing variable percentages of fat equivalent substance were used to assess the severity of fatty change of the rat liver. This was then correlated with the histological classification, level of hepatic enzymes, and graft survival. RESULTS: Linear correlation between the fat volume fraction added to the test tubes and CT density were found. The process of producing a fatty liver via diet alteration peaked at week 3. At this time hepatic enzymes, radiological fat content, and posttransplantation survival were worse (P=0.013), compared with other time points. Radiological assessment of fatty liver correlated well with survival and serum glutamic oxaloacetic transaminase and glutamic pyruvate transaminase levels. CONCLUSION: Severe microvesicular steatosis does not influence recipient survival, however, macrovesicular steatosis affects graft survival. Caliber CT is a practical and simple method that allows an accurate noninvasive quantitative assessment of hepatic fatty infiltration. It has potential to be a useful parameter for the assessment of donor livers for clinical liver transplantation.
Animals↗
Biomechanical effects of progressive anterior cervical decompression.
STUDY DESIGN: A repeated-measures in vitro flexibility test was performed. OBJECTIVES: To determine the biomechanical functions of tissues resected during anterior cervical decompression of various extents. SUMMARY OF BACKGROUND DATA: The biomechanical consequences of discectomy have been studied in vitro, and uncovertebral joint removal has been modeled numerically. No studies have assessed the relative biomechanical contributions of different anterior column structures. METHODS: In seven human cadaver C4-T1 specimens, 20 motion segments were studied. After each destructive step, including discectomy, unilateral uncinate process removal, bilateral uncinate process removal, and posterior longitudinal ligament transection, torques were applied to four-level specimens while the angular motion was measured at each level. RESULTS: Angular range of motion and neutral zone increased by variable but statistically significant amounts after each progressive resection, most notably in flexion and extension. Each resection step caused progressively larger shifts (up to 23 mm) in the location of the axis of rotation. Uncovertebral joint resection caused the most significant changes in the observed angular coupling. CONCLUSIONS: Anterior cervical decompression significantly increases the instability and alters the kinematics of cervical motion segments. Each structure resected contributes to normal stability and kinematics, so as many structures as possible should be left intact during anterior decompression without fusion. Because flexion and extension were the modes of motion that increased most significantly after decompression, the primary function of a grafting technique or fixation device should be to limit these motions.
Aged↗
Interventional radiologic procedures in liver transplantation.
Postoperative biliary and vascular complications contribute significantly to morbidity and mortality in liver transplantation. Interventional radiologists are an integral part of the multidisciplinary team necessary for optimizing the management of these complications. During a 15-year period, 39 cadaveric and 25 living related liver transplantations were performed at the Chang Gung Memorial hospital, Taiwan. Of 64 liver transplant recipients, 9 (3 adult and 6 pediatric) underwent 13 interventional radiological procedures for the treatment of biliary sludge-casts (n = 2), bile duct occlusion or stenosis (n = 2), hepatic veins thrombosis (n = 1), hepatic veins stenosis (n = 1), portal vein stenosis with splenorenal shunting (n = 1), biloma (n = 1), and infected fluid collection or ascites (n = 4). Antegrade or retrograde interventional approach was used to successfully treat all biliary complications, and all percutaneous drainage procedures were effective in the control of intra-abdominal fluid collections. Portal vein stenosis was treated by balloon dilatation, and the associated splenorenal shunt was closed by metallic coil embolization via transhepatic catheterization of the portal vein. Hepatic vein stenosis was effectively treated by balloon dilatation and expandable metallic stent deployment via transfemoral and jugular venous approaches, respectively. Hepatic vein thrombosis was only partially lysed by transvenous streptokinase administration, and surgical thrombectomy was needed to achieve complete recanalization. The total success rate of the interventional procedures was 92 % with no procedure-related complications. The overall survival rate in this series is 89 %, and all patients who underwent living related liver transplantation maintain to date a 100 % survival rate. We can conclude that interventional radiological procedures are very useful for managing biliary and vascular complications after liver transplantation. These techniques provide a cure in most situations, thus obviating the need for further surgical intervention or re-transplantation.
Adolescent↗
Penile curvature associated with scleroderma.
We present 2 cases of Peyronie's disease in patients with scleroderma. This association is uncommon, and our patients' symptoms and disease course differed from that typical for Peyronie's disease. We suggest a more conservative approach when treating patients whose penile curvature is associated with a systemic disease such as scleroderma.
Adult↗
Different fast-gate regulation by external Cl(-) and H(+) of the muscle-type ClC chloride channels.
The fast gate of the muscle-type ClC channels (ClC-0 and ClC-1) opens in response to the change of membrane potential (V). This gating process is intimately associated with the binding of external Cl(-) to the channel pore in a way that the occupancy of Cl(-) on the binding site increases the channel's open probability (P(o)). External H(+) also enhances the fast-gate opening in these channels, prompting a hypothesis that protonation of the binding site may increase the Cl(-) binding affinity, and this is possibly the underlying mechanism for the H(+) modulation. However, Cl(-) and H(+), modulate the fast-gate P(o)-V curve in different ways. Varying the external Cl(-) concentrations ([Cl(-)](o)) shifts the P(o)-V curve in parallel along the voltage axis, whereas reducing external pH mainly increases the minimal P(o) of the curve. Furthermore, H(+) modulations at saturating and nonsaturating [Cl(-)](o) are similar. Thus, the H(+) effect on the fast gating appears not to be a consequence of an increase in the Cl(-) binding affinity. We previously found that a hyperpolarization-favored opening process is important to determine the fast-gate P(o) of ClC-0 at very negative voltages. This [Cl(-)](o)-independent mechanism attracted little attention, but it appears to be the opening process that is modulated by external H(+).
Animals↗
The clinical use of small-dose tetracaine spinal anesthesia for transurethral prostatectomy.
UNLABELLED: In a double-blinded study, we compared conventional dose tetracaine (8 mg), small-dose tetracaine (4 mg) with added fentanyl and epinephrine, and small-dose tetracaine (4 mg) with added fentanyl subarachnoid anesthesia. Forty-five patients scheduled for transurethral resection of prostate (TURP) under subarachnoid anesthesia were randomly assigned to Group 1 (8 mg hyperbaric tetracaine), Group 2 (4 mg hyperbaric tetracaine, 10 microg fen-tanyl, and 0.2 mg epinephrine), and Group 3 (4 mg hyperbaric tetracaine, 10 microg fentanyl, and 0.2 mL saline). Evaluations were performed after spinal anesthesia. Subarachnoid block was successful in all patients except one in Group 1, who required general anesthesia by mask. The median peak sensory levels 10 min after the induction of spinal anesthesia in Group 1 was T8, which was significantly higher than Group 2 and Group 3 (P < 0.05). The time of sensory and motor recovery in Group 3 was less than in Groups 1 and 2 (P < 0.05). Hypotension was observed in four patients in Group 1 and none in Groups 2 and 3. We conclude that small-dose 4-mg hyperbaric tetracaine plus 10 microg fentanyl might provide adequate anesthesia and fewer side effects for TURP when compared with the conventional (8 mg) dose. IMPLICATIONS: Small-dose hyperbaric tetracaine (4 mg with 10 microg fentanyl added) may provide adequate anesthesia and fewer side effects for transurethral resection of the prostate.
Aged↗
Biliary complications in living related liver transplantation.
BACKGROUND: Biliary tract reconstruction has long been considered the Achilles' heel of liver transplantation as biliary complications can increase morbidity and mortality especially in partial liver graft transplantation. METHODS: Thirty-four living related liver transplants were performed at Chang Gung Memorial Hospital in Kaohsiung for 33 children and 1 adolescent during a 5.5-year period. All potential donors underwent a detailed preoperative imaging study of the vascular and biliary anatomy, including three-dimensional helical computed tomographic cholangiography (n = 20), magnetic resonance cholangiography (n = 14), and intra-operative cholangiography (n = 31) before graft retrieval. All hepatic artery anastomoses were performed in the standard microsurgery fashion and their patency was confirmed intra-operatively using Doppler ultrasound. RESULTS: The biliary complication rate was 8.8% (3/34), including multiple intrahepatic biliary stenosis of unknown origin (n = 1), bile leakage from the Roux-en-Y loop (n = 1), and a missed biliary radicle (n = 1) which were treated via interventional radiological and surgical procedures. The overall graft and patient survival rates were 100%. CONCLUSION: The biliary complication rate in this series was low compared to those of other experienced centers. Complete study of the variations of intrahepatic duct ramification pre-and-intra-operatively provided adequate information on the appropriate transection plane. Furthermore, intra-operative Doppler ultrasound verification of vessel patency helps prevent vascular complications, which has been identified as a cause of biliary complications.
Adolescent↗
Vaccination against gonadotropin-releasing hormone (GnRH) using toxin receptor-binding domain-conjugated GnRH repeats.
A method for the preparation of an immunogen containing multiple copies of a self-peptide in linear alignment was designed in order to overcome the difficulty of inducing an immune response to poorly immunogenic peptide antigens. DNA fragments encoding multiple repeats of the self-peptide were generated by a new technique, termed template-repeated polymerase chain reaction (TR-PCR), which could be subcloned into an expression vector for production of peptide repeats as an immunogen. This approach was tested by constructing fusion proteins containing the receptor-binding domain of Pseudomonas exotoxin A and multiple copies of the 10-residue sequence of the peptide hormone gonadotropin-releasing hormone (GnRH). Immunization of female rabbits with the immunogen that contained the exotoxin receptor-binding domain and 12 copies of GnRH (PEIa-GnRH12) resulted in the generation of high-titer antibodies specific for GnRH. Although at equal molar basis of the GnRH moiety, the immunogen that contained single copy of GnRH (PEIa-GnRH1) induced low-titer anti-GnRH antibodies. These observations suggest that the presence of multiple peptide repeats is a key factor in eliciting an immune response. In addition, anti-GnRH antibodies effectively neutralized GnRH activity in vivo, as demonstrated by the degeneration of the ovaries in the injected rabbits. Because anti-GnRH antibody could be functionally analogous to GnRH antagonist, which has been used to treat patients with ovarian cancer, vaccination of PEIa-GnRH12 presents a potential therapeutic application for the treatment of GnRH-sensitive ovarian cancer.
ADP Ribose Transferases↗
The clinical presentation of uppermost cervical disc protrusion.
OBJECT: The purpose of this study is to clarify the clinical presentation of the C2-C3 cervical herniation disc. SUMMARY OF BACKGROUND DATA: Uppermost cervical disc protrusion is an uncommon condition. The pattern of large central fragments of nucleus impinging on the highest cervical disc region is often poorly localized according to its clinical presentation. METHODS: Eight patients treated with anterior cervical discectomy with fusion for C2-C3 disc herniation participated in a detailed clinical and radiologic review to determine early detection and clarify potential hazards. Each patient's neurologic function was tested and recorded successively by a team of physicians and qualified physiotherapists. RESULTS: Reviewing the symptomatology, most patients presented ascending radicular symptoms secondary to trivial trauma, characterized by suboccipital pain, loss of hand dexterity, and paresthesia over face and unilateral lateral arm. Six (75%) patients had remarkable improvement postoperatively in neurologic function, except for some residual sensory embarrassment in at least 6 months follow-up. CONCLUSIONS: Clinical neurologic examination provides a less precise anatomic basis, to point to a particular upper cervical disc protrusion. Nonspecific neck and shoulder pain, a variety of cervical radiculopathy, and myelopathy may present. However, this rare spondylotic pattern is usually characterized by impairment of motor and sensory function more in the upper extremities than lower extremities and mostly starting following trauma. Radiculopathy generally outweighs the cord sign. Cruciate paralysis associated with vague diffuse and patch regions of hypesthesia over perioral distribution may help to localize this upper cervical lesion. The present study demonstrates that early detection and adequate anterior decompression may provide excellent outcome.
Aged↗
Correlation of homocytsteine levels with the extent of coronary atherosclerosis in patients with low cardiovascular risk profiles.
Elevation of homocysteine is now known as an independent risk factor for vascular diseases. However, influences of homocysteine to the extent of coronary atherosclerosis in patients with different coronary risk profiles have not been studied. In this study, we used angiographic "diffuse score" and "clinical vessel score" to evaluate the extent of coronary atherosclerosis, and examined the correlation between levels of serum total homocysteine and angiographic scores among patients with high- and low-risk profiles. Seventy consecutive patients (58 men and 12 women, mean age 50 years) undergoing selective coronary angiography for the first time were recruited for this study. Patients were divided into high-risk (risk factor > or =3, n = 35) and low-risk (risk factor <3, n = 35) groups. Linear regression analysis revealed that levels of serum homocysteine were only significantly correlated with diffuse (r = 0.217, p = 0.007) and clinical vessel (r = 0.078, p = 0.037) scores in low-risk patients. These correlations could not be observed in diffuse (r = 0.070, p = 0.319) and clinical vessel (r = -0.001, p = 0.970) scores in the high-risk group. In conclusion, levels of homocysteine correlated with the extent of coronary atherosclerosis only among patients with low cardiovascular risk profiles.
Coronary Angiography↗
Development of DNA delivery system using Pseudomonas exotoxin A and a DNA binding region of human DNA topoisomerase I.
Gene therapy is defined as the delivery of a functional gene for expression in somatic tissues with the intent to cure a disease. Thus, highly efficient gene transfer is essential for gene therapy. Receptor-mediated gene delivery can offer high efficiency in gene transfer, but several technical difficulties need to be solved. In this study, we first examined the DNA binding regions of the human DNA topoisomerase I (Topo I), using agarose gel mobility shift assay, in order to identify sites of noncovalent binding of human DNA Topo I to plasmid DNA. We identified four DNA binding regions in human DNA Topo I. They resided in aa 51-200, 271-375, 422-596, and 651-696 of the human DNA Topo I. We then used one of the four regions as a DNA binding protein fragment in the construction of a DNA delivery vehicle. Based on the known functional property of each Pseudomonas exotoxin A (PE) domain and human DNA Topo I, we fused the receptor binding and membrane translocation domains of PE with a highly positively charged DNA binding region of the N-terminal 198 amino acid residues of human DNA Topo I. The resulting recombinant protein was examined for DNA binding in vitro and transfer efficiency in cultured cells. The results show that this DNA delivery protein is a general DNA delivery vehicle without DNA sequence, topology, and cell-type specificity. The DNA delivery protein could be used to target genes of interest into cells for genetic and biochemical studies. Therefore, this technique can potentially be applied to cancer gene therapy.
ADP Ribose Transferases↗
Treatment of complicated hepatolithiasis with intrahepatic biliary stricture by ductal dilatation and stenting: long-term results.
A group of 190 cases of hepatolithiasis with postoperative residual stones located proximal to the stricture sites were managed with the aim of complete clearance of stones and relief of bile stasis to decrease the potential risk of recurrence. All procedures were performed through a T-tube track with gradual dilatation and stent placement through the stricture sites, creating a channel that allows cholangioscopy and electrohydraulic lithotripsy. Complete clearance of intrahepatic duct (IHD) stones was achieved in 88.4% of cases. Multiple sharply angulated IHD strictures in right-sided hepatolithiasis constituted a major cause of failure. Recurrent stone formation and repeated cholangitis, subsequent drainage, and liver resection are associated with high mortality rates particularly if there is late development of a cholangiocarcinoma. We concluded that postoperative ductal dilatation and stenting through the T-tube track combined with endoscopic electrohydraulic lithotripsy is effective and safe for managing complicated hepatolithiasis. Persistent irreversible aneurysmal dilatation of IHD and atrophic change of the affected hepatic lobe at follow-up were ominous signs of recurrence and cholangiocarcinoma development. Early drainage with stone extraction combined with surgical intervention can prevent subsequent morbidity and mortality.
Adult↗
Intraoperative Doppler ultrasound in living-related liver transplantation.
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Adolescent↗