Successful Ligation Research Articles

Successful Sequential Sac Ligation for an Unruptured Giant Omphalocele: Report of a Case

A giant omphalocele is difficult to treat and various methods have been tried with varying results. We describe a technique of sequential sac ligation to achieve rapid and gentle reduction of the herniated abdominal contents, followed by delayed primary closure of the abdominal wall defect.

Sturdier DNA Nanotubes via Ligation

DNA nanotubes are crystalline self-assemblies of DNA tiles approximately 10 nm in diameter that readily grow tens of micrometers in length. Easy assembly, programmability, and stiffness make them interesting for many applications, but DNA nanotubes begin to melt at temperatures below 40 degrees C, break open when deposited on mica or scanned by AFM, and disintegrate in deionized water. These weaknesses can be traced to the presence of discontinuities in the phosphate backbone, called nicks. The nanotubes studied here have five nicks, one in the core of a tile and one at each corner. We report the successful ligation of all four corner nicks by T4 DNA ligase. Although ligation does not change the nanotubes' stiffness, ligated nanotubes withstand temperatures over 70 degrees C, resist breaking during AFM, and are stable in pure water for over a month. Ligated DNA nanotubes are thus physically and chemically sturdy enough to withstand the manipulations necessary for many technological applications.

Early Spontaneous Slippage of Rubber Bands with Fatal Bleeding: a Rare Complication of Endoscopic Variceal Ligation

The risk of fatal massive bleeding after successful endoscopic variceal ligation (EVL) is very low [1]. To date, only a few reports have been published in the English-language literature on life-threatening bleeding due to ulceration following variceal banding [2] [3] [4]. The present report describes an additional case of this fatal complication resulting from early spontaneous slippage of rubber bands.

A Case of Rectal Dieulafoy’s Ulcer and Successful Endoscopic Band Ligation

Dieulafoy's ulcer is a rare cause of gastrointestinal bleeding. The lesion is usually located in the stomach, although it may occur anywhere in the gastrointestinal tract. A 44-year-old man was admitted to hospital due to cerebral infarction. On the 23rd day of hospitalization, he showed massive hematochezia. He underwent an urgent colonoscopy. There was a visible protuberant vessel without significant ulceration at the fundus of the rectum, consistent with a Dieulafoy's ulcer. It was treated by endoscopic hemoclipping. However, rebleeding occurred three times despite repeated hemoclipping. Finally, endoscopic band ligation was successfully performed to achieve permanent hemostasis. Endoscopic band ligation is an effective treatment for bleeding rectal Dieulafoy's ulcer.

Construction and characterization of an infectious molecular clone of HIV-1 subtype A of Indian origin

India has the second highest number of HIV-1 infected people next to South Africa. The predominant proportion of HIV-1 circulating in India is of subtype C origin, with a small fraction made up of subtypes A and B. In this report, we describe the construction and characterization of the first full-length infectious molecular clone p1579A-1 HIV-1, from an HIV-1 subtype A infected person from India, using long PCR and successive ligation of the amplimers. Phylogenetic analysis of the sequence of the entire proviral DNA and LTR confirmed p1579A-1 to be an HIV-1 subtype A. Analysis of the env gene of p1579A-1 showed a conserved GPGQ motif and the absence of basic amino acids at positions 11 and 25 suggesting CCR5 coreceptor usage. Analysis of env N-linked glycosylation sites revealed fewer sites in the V1 region of envelope compared to other subtype A. Transcription factor binding site analysis of the LTR sequences identified conserved as well as unique transcription factor binding sites (TFBS) in p1579A-1. This infectious clone of HIV-1 can be useful to study the molecular mechanism of dominance of subtype C in India.

Synthesis of 2‘-C-Difluoromethylribonucleosides and Their Enzymatic Incorporation into Oligonucleotides

[Chemical reaction: See text] Nucleosides bearing a branched ribose have significant promise as therapeutic agents and biotechnological and biochemical tools. Here we describe synthetic entry into a new subclass of these analogues, 2'-C-beta-difluoromethylribonucleosides. We constructed the glycosylating agent 4 in three steps from 1,3,5-tri-O-benzoyl-alpha-D-ribofuranose 1. The key steps included nucleophilic addition of difluoromethyl phenyl sulfone to 2-ketoribose 2 followed by mild and efficient reductive desulfonation. Ribofuranose 4 glycosylated bis(trimethylsilyl)uracil directly, giving difluoromethyluridine 7 efficiently after deprotection. Conversion of 4 to the corresponding ribofuranosyl bromide allowed efficient access to C, A, and G analogues. A related approach starting from methyl D-ribofuranose offered synthetic entry into the diastereomeric manifold, 2'-C-alpha-difluoromethyl-arabino-alpha-pyrimidine. To incorporate 2'-C-beta-difluoromethyluridine into an oligodeoxynucleotide we converted 7 to the bisphosphate and carried out successive ligation reactions using T4 RNA ligase and T4 DNA ligase. Analogous to natural RNA linkages, the resulting oligonucleotide undergoes hydroxide-catalyzed backbone scission at the difluoromethyluridine residue via internal transphosphorylation.

Congenital Heart Disease: A Surgical-Historical Perspective

Pediatric cardiac surgery began with Dr Gross's first successful ligation of a patent ductus arteriosus on August 8, 1938, at the Children's Hospital in Boston. The beginnings of open-heart surgery for repair of congenital malformations, aside from Gibbon's first successful closure in Philadelphia of an atrial septal defect using an artificial heart-lung machine, can be traced to members of the Department of Surgery at the University of Minnesota during the fifties and sixties of the 20th century. This story will be told, and other advances will be discussed, some of which also carry the imprint of the Minnesota surgical training program, with its heavy emphasis on research.

Redefining the Role of Arterial Imaging in the Management of Penetrating Zone 3 Neck Injuries

The purpose of this study was to assess the role of arteriography (AG) in the diagnosis and treatment of vascular trauma in patients with zone 3 penetrating neck injuries. The records of all cases of penetrating neck trauma for the past 14 years at a level 1 trauma center were reviewed retrospectively. Eight hundred forty-four penetrating neck injuries were documented, of which 72 (8.5%) traversed zone 3 of the neck (gunshot, 35; stab, 32; shotgun, 5). Twenty patients (27%) had hard signs of vascular injury (hemorrhage, expanding hematoma, bruit, thrill, neurologic deficit). Twelve of these (60%) underwent immediate exploration, 1 had no significant injury, and 11 had successful surgical repair or ligation of the vascular injury. AG in the other eight patients with hard signs revealed injuries requiring embolization (three patients), urokinase infusion (one patient), and observation (three patients) and one normal examination. Fifty-two patients had no hard signs of vascular injury. Twenty-four of these underwent AG, of which 18 were negative. Positive findings included internal carotid artery narrowings (two patients), external compression of the internal carotid artery (one patient), vertebral artery intimal flap (one patient), and nonbleeding injuries to small, noncritical arteries (two patients), none of which required treatment. Twenty-four of the remaining 28 patients were observed clinically, and 4 patients had negative explorations. Nine patients had ultrasonography performed, but these examinations did not yield any useful information. The absence of hard signs reliably excludes surgically significant vascular injuries in penetrating zone 3 neck trauma, suggesting that AG is not necessary. Hard signs in stable patients should mandate AG because these vascular injuries may be amenable to endovascular therapy.

Tethered DNA hairpins facilitate electrochemical detection of DNA ligation

A novel electrochemical assay for DNA ligase activity is described. The assay exploits the properties of DNA hairpins tethered at one terminus to a gold electrode and labelled at the other with a ferrocene group for rapid characterisation of DNA status by cyclic voltammetry. Successful ligation of 'nicked' DNA hairpins is indicated by retention of the ferrocene couple when exposure to DNA ligase is followed by conditions that denature the hairpin. The results demonstrate the simplicity of integrating electrochemical detection with hairpin based biosensors and illustrate a new approach to the assay of DNA ligases, of which the NAD(+)-dependent enzymes represent a potential broad spectrum antibacterial drug target.

Successful Surgical Ligation Under Intraoperative Portal Vein Pressure Monitoring of a Large Portosystemic Shunt Presenting as an Intrapulmonary Shunt: Report of a Case

We report a rare case of patent ductus venosus (PDV) with collapsed intrahepatic portal branches and an intrapulmonary shunt. Excellent improvement of the intrahepatic portal vein flow was achieved by ligating the large ductus venosus under intraoperative portal vein pressure (PVP) monitoring. A 3-year-old boy being followed up for hypergalactosemia at a local hospital was found to have mild lip cyanosis, exertional dyspnea, clubbed fingers, and mild liver dysfunction with high levels of transaminase and ammonia. Cardiac catheterization indicated an intrapulmonary shunt with a ratio of 33%. Abdominal ultrasonography and computed tomography showed remarkable communication between the portal vein and the inferior vena cava. We performed laparotomy and successfully ligated the PDV under PVP monitoring. The PVP did not increase until the catheter was removed 7 days postoperatively. The patient's liver function test results returned to normal within 2 weeks. His serum galactose level was 0 mg/dl after drinking milk, and his SpO2 in room air and exertional dyspnea also improved. He was discharged 18 days after his operation, without any complications. We propose that ligation of a PDV under PVP monitoring could be a treatment of choice, bearing in mind that PDV is associated with collapsed intrahepatic portal branches.

Splicing of unnatural amino acids into proteins: a peptide model study.

S-Ethyl 2-azidohexanethioate (N3-Hex-SEt), an unnatural amino acid analog of leucine, is coupled with L-cysteine ethyl ester (NH2-Cys-OEt) to obtain N3-Hex-Cys-OEt by native chemical ligation. Coupling of this dipeptide with N-t-butoxycarbonyl-2-diphenylphosphinoethanethioglycinate produces the tripeptide, t-Boc-Gly-Hex-Cys-OEt, in high yield. These reactions suggest an approach for the incorporation of unnatural amino acids into proteins by successive native chemical ligation and Staudinger ligation.

Total synthesis of artificial zinc‐finger proteins: Problems and perspectives

The total synthesis of a peptide segment corresponding to the DNA-binding segment of Sp1 (positions 532-623) using a native chemical ligation approach is described. The folding of the synthetic segment in the presence of Zn(II) gave a zinc-coordinated protein. The dissociation constant (K(D)) for the DNA binding of the resulting protein, determined by a gel mobility shift assay, was 130 nM, almost nine times higher than that of the genetically prepared protein. However, methylation interference assay showed an identical sequence specificity of both proteins in DNA recognition. The chemical ligation method to connect the respective zinc-finger units was also accomplished. Successive ligation between a cysteine-containing peptide segment and a chloroacetylated peptide segment gave an artificial three-finger protein, which corresponds to the above DNA-binding segment of Sp1. However, this protein failed to bind DNA, even at 1.25 mM. Assessment of their folding structure based on the absorption spectra of their Co(II) complexes showed that the linker design to connect the respective finger units is critical for the proper folding of the proteins as well as the occurrence of the DNA-binding function.

Surgical ligation of a residually patent arterial duct following failed occlusion using transcatheter coils

Transcatheter techniques for occlusion of the persistently patent arterial duct using coils have become standard therapy at many centers for pediatric cardiology, and in selected patients have demonstrated comparable efficacy to surgical ligation. Surgical ligation may still be required in many cases, including premature infants or those born with low weight, those with ducts of large diameter, those with associated structural heart disease, and in circumstances of unsuccessful occlusion subsequent to attempted closure using coils. We report on the successful surgical ligation of an arterial duct of moderate size that exhibited residual patency despite two separate attempts at occlusion using coils.

Retrograde embolisation of varicocele in the paediatric age group: a review of 10 years' practice.

To review the 10 years' practice of retrograde embolisation of varicoceles in the paediatric age group. 40 boys (age range, 6-16 years), with varicocele diagnosed both clinically and sonographically, were referred to the radiology department for embolisation. Data of these patients were collected and analysed retrospectively. Patients' age, side, treatment, complications, and outcome were noted. The follow-up ranges from 2 months to 6 years (mean, 1.1 years). In 24 patients (60%), embolisation was successful at the first attempt and 11 procedures (27.5%) were technical failures; 4 patients (10%) after venography were considered non-embolisable. One patient (2.5%) is yet to be seen in the clinic. Recurrence occurred in 4 patients (10%) of whom 3 had successful repeat embolisation. One patient with a recurrent varicocele did not wish further treatment. Out of the 11 failures, 5 underwent repeat embolisation with success in 3 patients and failure in two. Four patients had successful surgical ligation and 2 patients were treated conservatively. All who were non-embolisable were treated successfully by surgery. Our overall success rate was 65% (n = 26). These results suggest that embolisation is valuable as a first line of treatment for paediatric varicoceles provided a skilled interventional radiologist is available. This procedure is less invasive, avoids general anaesthetic, involves minimal postoperative pain, and allows an earlier return to normal activities. However, 35% of patients did eventually require conventional surgery for primary failure of embolisation or late recurrence.

An orthogonal oligonucleotide protecting group strategy that enables assembly of repetitive or highly structured DNAs.

A general problem that exists in the assembly of large and organized DNA structures from smaller fragments is secondary structure that blocks or prevents it. For example, it is common to assemble longer synthetic DNA and RNA fragments by ligation of smaller synthesized units, but blocking secondary structure can prevent the formation of the intended complex before enzymatic ligation can occur. In addition, there is a general need for protecting groups that would block reactivity of some DNA bases in a sequence, leaving others free to react or hybridize. Here we describe such a strategy. The approach involves the protecting group dimethylacetamidine (Dma), which we show to remain intact on exocyclic amines of adenine bases while other bases carrying commercially available 'ultra mild deprotection' protecting groups are removed by potassium carbonate in methanol. The intact Dma groups prevent unwanted hybridization at undesired sites, thus encouraging it to occur where intended, and allowing for successful ligations. The Dma group is then deprotected by treatment with ammonia in methanol. Other common amine protecting groups such as benzoyl and allyloxycarbonyl were not successful in such a strategy, at least in part because they did not prevent hybridization. We demonstrate the method in the synthesis of a circular 54mer oligonucleotide composed of nine human telomere repeats, which was not possible to assemble by conventional methods.

Salvage of poorly developed arteriovenous fistulae with percutaneous ligation of accessory veins

Many arteriovenous (AV) fistulae fail to achieve an adequate blood flow or size for successful cannulation because of accessory veins. We describe a simple technique to ligate accessory veins that does not require a surgical incision. In this retrospective study, 17 end-stage renal disease patients underwent ligation of accessory veins of poorly developed AV fistulae. There were 14 men and 3 women, and their average age was 50 ± 13 years. There were 14 radiocephalic and 3 brachiocephalic fistulae. After identifying accessory veins with a fistulogram, two nonabsorbable 2-0 polypropylene (Prolene) sutures were placed percutaneously around each accessory vein in proximity to the AV fistula. Successful ligation was confirmed with a repeat fistulogram. This procedure was undertaken after 4 ± 3 months following surgical placement. Successful maturation was defined as adequate blood flow to support effective hemodialysis and adequate caliber to allow for repeated cannulation with a 15G or 16G needle. Of 17 AV fistulae, 15 (88%) successfully matured 1.7 ± 1 month (range, 0.3 to 6 months) after the procedure. The average number of accessory veins ligated was 1.7 ± 0.8 (range, 1 to 3). All AV fistulae that matured after ligation of accessory veins were functioning at 44.5 ± 12 weeks after first use. A technique for salvaging nonmaturing AV fistulae not requiring surgical cutdown for ligation of accessory veins is described. AV fistulae mature quickly after ligation of accessory veins. This is a rapid and safe procedure that can increase the prevalence of AV fistulae. © 2002 by the National Kidney Foundation, Inc.

Successful surgical treatment of two cases of congenital chylous ascites

The authors report on 2 patients with congenital chylous ascites who underwent successful lymphatic duct ligation after a laparoscopic lymphoid dye test. Fetal ascites had been detected in both cases, and both babies were born with marked abdominal swelling. Given that conservative treatment by medium-chain triglyceride (MCT) milk and total parenteral nutrition (TPN) was ineffective, the authors elected to perform lymphatic duct ligation on the 95th postnatal day in the former case and on the 27th postnatal day in the latter case. Lipophilic dye was administered preoperatively both through oral and subcutaneous routes, and the peritoneal cavity was explored using laparoscopy. This laparoscopic lymphoid dye test precisely identified the area of chylous leakage, and the authors were able to repair the malformed lymphatic duct directly at laparotomy. Both postoperative courses have been favorable with no recurrence of symptoms. The lymphatic duct ligation should be considered in cases resistant to conservative treatment for over a month. The present laparoscopic lymphoid dye test is a novel and useful procedure that allows surgeons to identify the exact location of chylous leakage, and thus successfully ligate the lymphatic duct. J Pediatr Surg 36:1717-1719. Copyright © 2001 by W.B. Saunders Company.

Thoracoscopic thoracic duct ligation for traumatic chylothorax

Traumatic chylothorax requires surgical intervention when conservative medical management fails to reduce chyle leakage. This usually entails thoracotomy or laparotomy. We report a case in which successful ligation of a torn thoracic duct was achieved using a video-assisted thoracoscopic technique.

Successful VATS ligation of a large anomalous branch producing IMA steal syndrome after MIDCAB

The occurrence of a flow “steal phenomenon” from a large branch of the internal mammary artery (IMA) is rare and its pathogenesis is still controversial. We describe a case of a patent large anomalous left IMA branch which produced recurrent angina 3 years post MIDCAB. Transcatheter coil obliteration of the vessel produced symptomatic relief. However, six months later, chest pains recurred in association with unwinding of the coil and recannulization of the collateral vessel. Successful ligation of the culprit branch using a VATS approach is presented.

Efficient transformation system for Propionibacterium freudenreichii based on a novel vector.

A 3.6-kb endogenous plasmid was isolated from a Propionibacterium freudenreichii strain and sequenced completely. Based on homologies with plasmids from other bacteria, notably a plasmid from Mycobacterium, a region harboring putative replicative functions was defined. Outside this region two restriction enzyme recognition sites were used for insertion of an Escherichia coli-specific replicon and an erythromycin resistance gene for selection in Propionibacterium. Hybrid vectors obtained in this way replicated in both E. coli and P. freudenreichii. Whereas electroporation of P. freudenreichii with vector DNA isolated from an E. coli transformant yielded 10 to 30 colonies per microg of DNA, use of vector DNA reisolated from a Propionibacterium transformant dramatically increased the efficiency of transformation (> or =10(8) colonies per microg of DNA). It could be shown that restriction-modification was responsible for this effect. The high efficiency of the system described here permitted successful transformation of Propionibacterium with DNA ligation mixtures.