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Biomedical subjects

H Y Song

Publications and source records attributed to H Y Song.

At least 73 records · Page 4Linked to original sources
PubMed1994

Covered, expandable esophageal metallic stent tubes: experiences in 119 patients.

PURPOSE: To study fluoroscopic placement of covered expandable stent tubes in patients with esophagogastric strictures. MATERIALS AND METHODS: Under fluoroscopic guidance, 132 stent tubes were placed in 116 patients with malignant neoplasm; four, in three patients with benign lesions. All patients had aphagia or dysphagia to soft food or liquid. RESULTS: After placement (successful in 100% of cases), 93 (78%) of the patients could ingest solid food; 24 (20%), soft food. Complications in the 119 patients included blockage in 13, stent tube migration in 12, gastroesophageal reflux in nine, severe pain in nine, and delayed massive bleeding in four. Most major complications were managed by means of a balloon catheter, a second stent tube, or analgesics. One hundred four patients died 2-80 weeks after stent placement. CONCLUSION: Treatment with placement of a covered expandable stent tube is effective in most patients with dysphagia due to malignant esophogastric strictures and is less effective in patients with benign strictures.

Catheterization↗
PubMed1993

Complete obstruction of the nasolacrimal system. Part I. Treatment with balloon dilation.

Fluoroscopically guided balloon dilation in treatment of complete obstruction of the nasolacrimal system was assessed in 39 eyes of 35 patients. All patients had severe epiphora. With nasal endoscopic guidance, a 0.018-inch guide wire was introduced through the superior punctum into the inferior meatus of the nasal cavity and was pulled out through the nasal aperture with a hemostat. A deflated angioplasty balloon catheter was passed retrograde over the guide wire through the inferior meatus until it straddled the stricture. Balloons were dilated with water-soluble contrast medium. No major complications occurred. At 7 days after balloon dilation, epiphora decreased in 22 of 39 eyes; 17 demonstrated complete resolution of severe epiphora, and five showed incomplete resolution. At 2 months, improvement had not been maintained in 10 of the 22 eyes. This technique for treatment of complete obstruction of the nasolacrimal system is simple and safe, but the high failure and recurrence rates in this study are not encouraging.

Adolescent↗
PubMed1993

Complete obstruction of the nasolacrimal system. Part II. Treatment with expandable metallic stents.

To evaluate the clinical usefulness of expandable metallic stents for maintenance of the dilated nasolacrimal sac and duct, double stents were implanted under fluoroscopic guidance in seven patients with severe epiphora after failed balloon dacryocystoplasty. Stents were constructed of 0.25-mm stainless steel wire in a cylindrical zigzag configuration of 10 bends. A single stent was 4 mm in diameter when fully expanded and 10 mm long. The stent was placed accurately in all but one patient, in whom a second stent was placed accurately after removal of the dislodged stent with a hemostat under endoscopic guidance. After stent placement, all patients demonstrated complete resolution of epiphora. During follow-up of 4-20 weeks, complete blockage of the stent occurred in one patient. This was treated with intrastent balloon dacryocystoplasty. No stents migrated. Although the long-term validity of this treatment has not been proved, expandable metallic stents seem to be of value in the treatment of complete obstruction of the lacrimal sac and nasolacrimal duct.

Adult↗
PubMed1993

Esophagorespiratory fistula associated with esophageal cancer: treatment with a Gianturco stent tube.

A self-expanding silicone-covered tube constructed of Gianturco stents was used for palliative treatment of esophagorespiratory fistula related to esophageal carcinoma in eight patients. All eight were unable to swallow food or water before treatment. The tubes were inserted under fluoroscopic guidance, without technical failure or complication. Clinical improvement was determined by grading food intake capacity on a five-point scale: none, liquid, soft food, most food, or all food. After the procedure, all fistulas were occluded. Four patients could swallow most foods, two could swallow soft food, one could swallow all foods, and one (who died of preexisting pneumonia 10 days after the procedure) could manage only liquids. Three patients were surviving without symptoms of aspiration for 4-24 weeks. Four patients died 6-16 weeks after placement of the stent tubes. Insertion of a silicone-covered stent tube was an effective palliative treatment for esophagorespiratory fistulas caused by esophageal cancer.

Bronchial Fistula↗
PubMed1993

[Antipyretic and anti-inflammatory effects of Artemisia annua L].

The antipyretic, heat-resisting anti-inflammatory analgesic and bacteriostasis effects of water extracts ethyl-acetate and n-butyl alcohol extracts of Artemisia annua are reported. Animal experiment has demonstrated that qinghao acid is one of the actively bacteriostatic constituents. Scopoletin is one of the anti-inflammatory constituents of Artemisia annua.

Animals↗
PubMed1992

Dynamic properties of the colicin E1 ion channel.

The mechanism of channel formation and action of channel-forming colicins is a paradigm for the study of dynamic aspects of membrane-protein interactions. The following experimental results concerning interaction of the colicin E1 channel domain with target membranes, in vitro and in vivo, are discussed: (1) the nature of the translocation-competent state of the channel-forming domain; (2) unfolding of the colicin channel peptide during in vitro binding and anchoring of the channel to liposome membranes at acidic pH; (3) reversal of channel peptide binding to liposomes by an alkaline-directed pH shift; (4) voltage-driven translocation and gating of the ion channel, discussed in the context of a four-helix model for a monomeric channel; (5) rescue of colicin-treated cells by high levels of external K+; (6) trypsin rescue of cells depolarized by the colicin ion channel; and (7) interaction of the channel domain with its immunity protein.

Amino Acid Sequence↗
PubMed1992

Corrosive esophageal stricture: safety and effectiveness of balloon dilation.

The safety and long-term effectiveness of fluoroscopically guided balloon dilation for corrosive esophageal stricture was evaluated in 22 patients with a follow-up period of more than 1 year (range, 13-52 months). The average interval between corrosive agent ingestion and initial balloon dilation was 18 years (range, 2 months to 51 years). Balloons with a diameter of 5-8 mm were used in the initial attempt. The caliber of the balloon catheter was increased gradually over subsequent dilations, up to a diameter that allowed patients to swallow solid foods. Dilation of more than 17 mm in diameter was performed in five patients. Patients underwent one to five sessions. Esophageal rupture occurred in seven patients and was treated nonoperatively in five and surgically in two. With exclusion of these latter two, 11 of 20 could tolerate swallowing all kinds of food and nine could tolerate swallowing most foods. Balloon dilation in corrosive esophageal strictures is effective, but the high rupture rate indicates the need for extra caution.

Acetates↗
PubMed1992

Esophageal strictures: treatment with a new design of modified Gianturco stent. Work in progress.

To overcome the drawbacks of the modified Gianturco stent tube with barbs, a new barbless stent tube was constructed. Twenty-two barbless stent tubes 4.5-14.0 cm long were placed with a new introducing tube in 21 patients: 10 stent tubes in 10 patients with recurrent dysphagia after radiation therapy or chemotherapy, 10 in 10 patients with esophageal cancer in whom surgical management was contraindicated, and two in one patient with postoperative benign stricture. No technical failure or procedural complications occurred. After the procedure, all but two patients could ingest most or all foods. In two patients with an esophagorespiratory fistula and one patient with esophageal rupture, the barbless stent tube successfully occluded the fistula and rupture site. The stent tube migrated in one patient. Fifteen patients are surviving, with the stent tubes patent for 3-35 weeks (mean patency, 13 weeks); the six other patients died 7-24 weeks (mean, 16 weeks) after stent placement. It is concluded that barbless stent tubes show promise in the management of dysphagia caused by esophageal strictures.

Aged↗
PubMed1992

Nonoperative management of persistent sciatic artery aneurysm--a case report.

A patient with a sciatic artery aneurysm, which is so rare that only 31 cases have been reported in the literature to date, was treated successfully with transcatheter arterial embolization (TAE) alone. Potentially risky and difficult surgery was avoided. This was the first trial with a good result. TAE alone is simple, safe and effective method for the treatment of sciatic artery aneurysm either in incomplete type or in complete type with adequate collateralization.

Aged↗
PubMed1992

Percutaneous transhepatic biliary biopsy using gastrofiberscopic biopsy forceps.

To obtain a histopathologic diagnosis at the site of a biliary obstruction, we recently have performed 24 cases of biliary biopsy using gastrofiberscopic biopsy forceps (Olympus, Tokyo, Japan) via transhepatic tracts provided in the course of the procedure of percutaneous biliary drainage. Histopathologic diagnosis was successfully made at the first attempt of biopsy procedure but a second trial was made a week later in 6 cases who were negative for malignant cells on the first attempt. The histological results from the biopsy specimens were 18 adenocarcinomas, 5 chronic inflammations and one normal epithelium. Of 6 cases who were negative for malignant cells on forceps biopsy specimen, three cases were confirmed as adenocarcinoma of the ampulla of Vater, adenocarcinoma of the pancreas and chronic pancreatitis by surgical biopsy. The latter was a true negative result, which was diagnosed as chronic inflammation on forceps biopsy and verified as chronic pancreatitis by surgery. The remaining two cases were diagnosed as malignant obstructive jaundice by clinical and radiological follow-up findings. Major complications (bile peritonitis, bleeding, and hemopneumothorax) occurred in 3 patients, which mainly arose in the earlier period of study. This procedure can be performed at the same time as percutaneous transhepatic biliary drainage with low morbidity or mortality, and although the potential for perforation of bile ducts and injury to adjacent blood vessels is considered it is a useful addition to existing biopsy techniques for yielding material sufficient for histologic analysis.

Adult↗
PubMed1991

Membrane topography of ColE1 gene products: the hydrophobic anchor of the colicin E1 channel is a helical hairpin.

The paucity of crystallographic data on the structure of intrinsic membrane proteins necessitates the development of additional techniques to probe their structures. The colicin E1 ion channel domain contains one prominent hydrophobic region near its COOH terminus that has been proposed to be an anchor for the assembly of the channel. Saturation site-directed mutagenesis of the hydrophobic anchor region of the colicin E1 ion channel was used to probe whether it spanned the bilayer once or twice. A nonpolar amino acid was replaced by a charged residue in 29 mutations made at 26 positions in the channel domain. Substitution of the charged amino acid at all positions except those in the center of the hydrophobic region and the periphery of the hydrophobic region caused a large decrease in the cytotoxicity of the purified mutant colicin E1 protein. This result implies that the hydrophobic domain spans the membrane bilayer twice in a helical hairpin loop, with the center of this domain residing in an aqueous or polar phase. The lengths of the trans-membrane helices appear to be approximately 18 and 16 residues. The absence of significant changes in ion selectivity in five of nine mutants indicated that these mutations did not cause a large change in the channel structure. The ion selectivity changes in four mutants and those previously documented for the flanking Lys residues imply that the hydrophobic hairpin is part of the channel lumen. Water may "abhor" the hydrophobic side of the channel, explaining the small effects of residue charge changes on ion selectivity.

Amino Acid Sequence↗
PubMed1991

Membrane topography of ColE1 gene products: the immunity protein.

The topography of the colicin E1 immunity (Imm) protein was determined from the positions of TnphoA and complementary lacZ fusions relative to the three long hydrophobic segments of the protein and site-directed substitution of charged for nonpolar residues in the proposed membrane-spanning segments. Inactivation of the Imm protein function required substitution and insertion of two such charges. It was concluded that the 113-residue colicin E1 Imm protein folds in the membrane as three trans-membrane alpha-helices, with the NH2 and COOH termini on the cytoplasmic and periplasmic sides of the membrane, respectively. The approximate spans of the three helices are Asn-9 to Ser-28, Ile-43 to Phe-62, and Leu-84 to Leu-104. An extrinsic highly charged segment, Lys-66 to Lys-74, containing seven charges in nine residues, extends into the cytoplasmic domain. The specificity of the colicin E1 Imm protein for interaction with the translocation apparatus and the colicin E1 ion channel is proposed to reside in its peripheral segments exposed on the surface of the inner membrane. These regions include the highly charged segment Lys-66 to Lys-83 (loop 2) and the short (approximately eight-residue) NH2 terminus on the cytoplasmic side, and Glu-29 to Val-44 (loop 1) and the COOH-terminal segment Gly-105 to Asn-113 on the periplasmic side.

Alkaline Phosphatase↗
PubMed1991

Esophagogastric neoplasms: palliation with a modified gianturco stent.

Self-expanding metallic stents of a modified Gianturco design were used for palliative treatment of malignant esophagogastric strictures. Over a 10-month period, 10 stents were placed in nine patients. All patients with severe dysphagia due to malignant strictures in whom all other treatment options had failed were candidates for these stents. Neither extensive length of esophageal involvement nor complete esophageal obstruction was a contraindication. All stents were placed with fluoroscopic guidance without any technical failures or procedural morbidity or mortality. Mild reflux occurred in three patients in whom the stent tubes straddled the distal esophageal sphincter. Five patients were still alive after 1-8 months. The remaining four patients died 6-28 weeks after stent placement; all stents were patent at the time of death. These stents are easy to insert, safe, and reasonably effective for short-term palliative treatment of esophagogastric neoplasms.

Adenocarcinoma↗
PubMed1990

Structure and dynamics of the colicin E1 channel.

The toxin-like and bactericidal colicin E1 molecule is of interest for problems of toxin action, polypeptide translocation across membranes, voltage-gated channels, and receptor function. Colicin E1 binds to a receptor in the outer membrane and is translocated across the cell envelope to the inner membrane. Import of the colicin channel-forming domain into the inner membrane involves a translocation-competent intermediate state and a membrane potential-dependent movement of one third to one half of the channel peptide into the membrane bilayer. The voltage-gated channel has a conductance sufficiently large to depolarize the Escherichia coli cytoplasmic membrane. Amino acid residues that affect the channel ion selectivity have been identified by site-directed mutagenesis. The colicin E1 channel is one of a few membrane proteins whose secondary structures in the membrane, predominantly alpha-helix, have been determined by physico-chemical techniques. Hypothesis for the identity of the trans-membrane helices, and the mechanism of binding to the membrane, are influenced by the solved crystal structure of the soluble colicin A channel peptide. The protective action of immunity protein is a unique aspect of the colicin problem, and information has been obtained, by genetic techniques, about the probable membrane topography of the imm gene product.

Amino Acid Sequence↗
PubMed1990

Changes in plasma levels of tissue plasminogen activator and its inhibitor in aged myocardial infarction patients.

Plasma levels of tissue plasminogen activator (tPA) antigen, tPA activity and plasminogen activator inhibitor (PAI) activity were determined in 40 cases of acute myocardial infarction (AMI) at the onset and 2-4 weeks after the onset of the disease. 24 healthy subjects served as controls. At the onset of AMI, mean plasma level of tPA antigen was significantly higher than that of control subjects (13.5 +/- 4.8 ng/ml vs 6.4 +/- 2.0 ng/ml), with the highest elevation in the group greater than 65 years of age. Mean plasma level of tPA activity was significantly lower than in the controls (1.1 +/- 0.4 IU/ml vs 1.6 +/- 0.4 IU/ml), especially in patients over 65 years of age. Mean plasma level of PAI activity was significantly higher than in the controls (17.5 +/- 12.0 AU/ml vs 9.0 +/- 4.6 AU/ml), especially in patients over 65 years of age. At 2-4 weeks, mean plasma levels of tPA and PAI activities of AMI patients had dropped to 1.5 +/- 0.6 IU/ml and 9.5 +/- 8.9 AU/ml, respectively, not significantly different from controls. The tPA antigen had come down to 11.0 +/- 5.4 ng/ml, but still higher than in the controls. The possible mechanism of these phenomena was discussed.

Aged↗
PubMed1990

Production and characterization of monoclonal antibodies against tissue-type plasminogen activator.

Four hybridoma clones, TA1, TA2, TA3 and TA4, producing monoclonal antibodies against t-PA were obtained by fusion of mouse myeloma cells (SP2/0 or NS-1) with mouse spleen cells previously immunized with purified t-PA. The antibody titers of the four hybridoma ascites were higher than 1 x 10(5) determined by ELISA. The double immune diffusion test showed that all hybridoma supernatants contained mouse IgG1. These monoclonal antibodies reacted only with t-PA, and rt-PA prepared by genetic engineering, but not with UK. t-PA, activity was inhibited by these monoclonal antibodies completely.

Animals↗
PubMed1989

Radiological evaluation of hepatic artery aneurysms.

The authors report 4 cases of hepatic artery aneurysm confirmed by computed tomography, sonography, angiography, and/or surgery. Three aneurysms involved the right hepatic artery and 1 involved the common hepatic artery. Two cases were treated with surgery, and the other 2 cases with transcatheter embolization. The clinical and radiological features of this entity are described together with a review of the pertinent literature.

Adult↗