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At least 343 records · Page 19Linked to original sources
PubMed1989

Safety of metallic surgical clips in patients undergoing high-field-strength magnetic resonance imaging.

Use of metallic clips with ferromagnetic properties in patients undergoing a large variety of surgical procedures, and in particular, in coronary artery and other vascular reconstructions, has become increasingly popular. The safety of these commonly used surgical clips when subjected to high-intensity diagnostic magnetic resonance imaging fields is still debated. Commonly used hemostatic metallic clips manufactured by the Weck and US Surgical Corporations were tested in an in vitro system to assess their safety with regard to migration and displacement. The two tested hemostatic metallic clips proved safe and did not migrate or become dislodged when they underwent magnetic resonance imaging scans. This is in direct contrast to multiple cerebral aneurysm clips, also tested, which have highly ferromagnetic properties and were previously shown to migrate with disastrous results in patients undergoing diagnostic magnetic resonance imaging scans. This study supports the continued widespread use of small metallic hemostatic clips in the myriad of procedures in which they are presently used and illustrates the need for methods of evaluating such devices before they are clinically implanted.

Electromagnetic Fields↗
PubMed1988

Clip-induced analgesia and immobility in the mouse: pharmacological characterization.

A pinch to the nape of the neck of mice, by application of a noxious clip, produces analgesia and immobility. Because both opiate and dopaminergic systems are usually implicated in analgesia and immobility, the pharmacological profile of clip-induced effects was compared to those elicited by the dopamine antagonist haloperidol, and by morphine. In addition, the effects of a series of pharmacological agents on clip-induced effects was examined. Haloperidol, but not morphine, produced immobility similar to that seen after application of the clip to the neck. Application of clip completely inhibited righting in all tests utilized. Haloperidol inhibited righting in all tests, except for inversion from a supine position. Righting from this position could also be inhibited in mice treated with haloperidol when a mild pinch, ineffective in a naive animal, was applied. Clip-induced immobility, but not analgesia, was reversed by amphetamine. Administration of the cholinergic antagonist scopolamine, but not methylscopolamine, reversed both the analgesia and immobility. Pinch-induced analgesia was as marked as that elicited by morphine but could not be reversed by the opiate antagonist naloxone. It is proposed that pinch-induced immobility is mediated by both dopaminergic and cholinergic systems. Additional unidentified systems are also involved. Analgesia, induced by a noxious pinch, can be dissociated pharmacologically from the immobilizing effect, is non-opiate in nature, and involves activation of central cholinergic synapses.

Analgesia↗
PubMed1992

CLIP-170 links endocytic vesicles to microtubules.

Binding of endocytic carrier vesicles to microtubules depends on the microtubule-binding protein CLIP-170 in vitro. In vivo, CLIP-170 colocalizes with a subset of transferrin receptor-positive endocytic structures and, more extensively, with endosomal tubules induced by brefeldin A. The structure of CLIP-170 has been analyzed by cloning its cDNA. The predicted non-helical C- and N-terminal domains of the homodimeric protein are connected by a long coiled-coil domain. We have identified a novel motif present in a tandem repeat in the N-terminal domain of CLIP-170 that is involved in binding to microtubules. This motif is also found in the Drosophila Glued and yeast BIK1 proteins. These features, together with its very elongated structure, suggest that CLIP-170 belongs to a novel class of proteins, cytoplasmic linker proteins (CLIPs), mediating interactions of organelles with microtubules.

Amino Acid Sequence↗
PubMed1987

Magnetic field effects on surgical ligation clips.

Magnetic forces exerted on surgical clips and the magnetic resonance imaging distortion they create in phantoms and rabbits at magnetic field strengths of 1.5 Tesla were investigated. Results are reported for both ligation and aneurysm clips manufactured from three types of stainless steel as well as titanium, tantalum and niobium metals. Paramagnetism and eddy currents were measured in a customized moving Gouy balance. Direct measurements of other magnetic forces were carried out in a 1.5T MRI system. The titanium and tantalum clips showed the least interaction with the magnetic field, both in terms of forces exerted and the observed image distortion with the larger clips generating the larger interactions. The strongest field distortions and attractive forces occurred with 17-7PH stainless steel clips. These interactions were ferromagnetic in origin and of sufficient strength to present significant risk to patients having this type of clip present during an MRI scan.

Animals↗
PubMed2004

Endovascular therapy versus surgical clipping for basilar artery bifurcation aneurysm: retrospective analysis of 117 cases.

OBJECTIVE: The purpose of this study was to retrospectively evaluate and compare the feasibility, indication and limitations of two treatment options, clipping and coil embolization, for basilar artery (BA) bifurcation aneurysms. MATERIALS AND METHODS: During the last 13 years, 117 patients with 117 BA bifurcation aneurysms were treated exclusively with direct surgery until February 1997, and with either direct surgery or coil embolization therapy since March 1997. Of them, 76 (65%) aneurysms were treated with direct clipping and 41 (35%) were treated with Guglielmi detachable coils (GDCs) embolization. The 76 surgically clipped aneurysms were analyzed on the basis of the pre-operative angiograms as to whether coil embolization would be feasible or not if each case had been attempted. The 41 embolized aneurysms, on the other hand, were analyzed as to whether clipping surgery would be feasible or not if it had been attempted. RESULTS: In the total 117 aneurysms, complete coil obliteration was judged to be possible and simple in 61 (52%) aneurysms, possible with complex techniques (difficult) in 29 (25%) and impossible in 27 (23%). Whereas, complete obliteration with direct clipping was judged to be simple in 66 (57%) aneurysms, difficult in 38 (32%) and impossible in the remaining 13 (11%). Linear correlation as to the technical difficulty was found in 61 (52%) aneurysms, but 14 (12%) had marked discrepancy between the two methods. Of the 76 patients treated with clipping surgery, 17 (22%) were left with some post-operative neurological deficits, and in six out of the 17 aneurysms, embolization might have been simple. There were complications in two patients; one procedure-related and the other with late re-bleeding due to aneurysmal re-growth, in the embolization, group. CONCLUSIONS: Endovascular therapy is an effective alternative for treating BA bifurcation aneurysms, although a quarter of the cases cannot be obliterated completely. It is important to select a suitable treatment option in each case depending on the patient's condition and the angiographical features of each aneurysm as well as the characteristics of the two methods.

Adult↗
PubMed1998

Are allergic reactions to skin clips associated with delayed wound healing?

BACKGROUND: Metal skin clips are used in surgery. They may contain metals that might cause allergic reactions and delayed wound healing. METHODS: The metal composition of 18 different surgical clamps was examined. The allergy status of 184 patients was determined by patch tests and was correlated with the clinical outcome of wound healing after application of skin clips. RESULTS: Skin clips contained chromium, nickel, molybdenum, cobalt, and titanium in concentrations high enough to cause allergic reactions. Eighteen percent of the men and 23% of the women were sensitive to nickel and 16% of the men to chromium. We found a positive correlation between the grade of nickel allergy and the reaction to the skin clips. CONCLUSIONS: Our study suggests that allergic reactions and delayed wound healing can be caused by the use of surgical skin clips. Therefore skin clips are not recommended for patients with a history of contact dermatitis to metals and/or atopy.

Adolescent↗
PubMed1999

Preliminary prospective randomized experience with vascular clips in the creation of arteriovenous fistulae for hemodialysis.

BACKGROUND: A new vascular clipping system (VCS) has been introduced for clinical use. This study was developed to determine whether patency rates and treatment outcomes for anastomoses in hemodialysis access surgery can be improved by the application of this new technology. METHODS: During a 10-month period, 96 consecutive patients requiring autologous fistula, synthetic fistula, or graft revisions for hemodialysis were prospectively randomized into two treatment groups. Anastomoses were constructed with the VCS in 46 patients and with polytetrafluoroethylene (PTFE) suturing in 49 patients. The procedures were performed in an outpatient setting, at a large medical center, by one surgeon. Time to construct the anastomosis, amount of bleeding from the anastomotic site, and primary and secondary graft patencies were analyzed. RESULTS: The mean time to construct anastomoses in autologous and synthetic grafts using VCS clips was significantly shorter than with sutures (autologous 14 versus 22 minutes, P = 0.0001; and new grafts 26 versus 30 minutes, P = 0.04). Blood loss was less in anastomoses done with the VCS clip; however, statistical significance was reached only for autologous fistulas (P = 0.0001). At 2-year follow-up, primary and secondary patencies were similar for both the VCS and suture groups with the exception that a statistically significant improvement was found in secondary patency for autologous fistulas when performed with the VCS. CONCLUSIONS: The VCS clip is easy to use and produces a more rapid anastomosis with less bleeding. Primary and secondary patencies using the VCS clip were equivalent or improved when compared with standard suture. In our experience, no complications have been attributed to the use of the clip technique.

Anastomosis, Surgical↗
PubMed2003

Effect of suture size and carotid clip application upon blood flow and infarct volume after permanent and temporary middle cerebral artery occlusion in mice.

Problems with the intraluminal suture method for induction of focal cerebral ischemia in genetically altered mice include occurrence of subarachnoid hemorrhage (SAH) and variability of infarct volume. We hypothesized that use of 5-0 curved or 6-0 straight suture for carotid cannulation might decrease SAH and that the application of a microvascular clip to the common carotid artery (CCA) might decrease variability of infarct volume. The purpose of this study is to evaluate and explain the results of these technical modifications. Strain related differences in vascular anatomy were evaluated. Male C57BL/6 mice were divided into two groups for permanent and temporary middle cerebral artery occlusion (MCAO). Results of 5-0 curved suture and 6-0 straight suture insertion with and without CCA clip application were examined. Cerebral perfusion was monitored by laser-Doppler flowmetry and infarct volume was measured. After permanent MCAO, larger and more consistent infarct volumes resulted using CCA clip application with a 6-0 but not with a 5-0 suture. After temporary MCAO, the SAH rate was 12.5% with a 5-0 curved suture and 11.1% with a 6-0 straight suture. A 40% rate was observed in a pilot study with 5-0 straight suture. Infarct volume after temporary MCAO with a CCA clip was significantly larger and variability of infarct volume was smaller than without the CCA clip using 5-0 curved and 6-0 straight suture. In summary, SAH is less frequent using a 5-0 curved or 6-0 straight suture. Infarct volume is enlarged by application of a CCA clip (249).

Animals↗
PubMed2000

Influence of a 1-h immobilization stress on sleep and CLIP (ACTH(18-39)) brain contents in adrenalectomized rats.

Basal sleep amounts in adrenalectomized rats (AdX), as compared to intact animals, exhibit a significant increase in slow-wave sleep (SWS), a tendency towards an increase in paradoxical sleep (PS), and circadian rhythms (SWS and PS) flattened in amplitude. An immobilization stress (IS) of 1 h, imposed on AdX rats at the beginning of the dark period, is accompanied by an intense polygraphic waking. Just after the IS, SWS amount become significantly higher than in control rats (+44%/11 h of darkness) whereas significant increases of PS occur only 5-10 h after the IS (+24%/11 h of darkness). A specific radioimmunoassay for CLIP (corticotropin-like intermediate lobe peptide or ACTH(18-39)) was performed in biopsies taken either from the nucleus raphe dorsalis (nRD) or the arcuate nucleus (AN). In the nRD, just after the IS, phosphorylated CLIP (Ph-CLIP) concentration exhibits a decreasing tendency, but 4 h later, it increases significantly (+22%, p<0.05). In the AN, Ph-CLIP concentration remains unchanged after the IS as well as 4 h later. These results differ from those previously reported in intact animals also submitted to a 1-h IS, that is, a SWS rebound less marked (+27%/11 h of darkness), a PS rebound more important starting immediately after the IS (+46%/11 h of darkness) and a significant increase in Ph-CLIP occurring just after the end of the restraint. In conclusion, data obtained after a restraint stress either in AdX or in control rats point out the dependence of the PS rebound on the nRD Ph-CLIP concentration.

Adrenalectomy↗
PubMed2000

Two randomized controlled trials comparing the tubal ring and filshie clip for tubal sterilization.

OBJECTIVE: To compare the effectiveness and safety of the Filshie Clip and Tubal Ring systems when applied via minilaparotomy and laparoscopy. DESIGN: Prospective, multicenter randomized controlled clinical trial, with postoperative evaluation by a physician who was masked to the operative technique. SETTING: Healthy volunteers in a variety of hospital settings. PATIENT(S): 2746 women (915 in the minilaparotomy study and 1831 in the laparoscopy study) who had requested permanent surgical sterilization. INTERVENTION(S): Surgical tubal ligation, using either Filshie Clips or Tubal Rings. A physician other than the surgeon evaluated the patients after the operation and again at 1, 6, and 12 months after surgery. MAIN OUTCOME MEASURE(S): Pregnancy rates and safety-related events. RESULT(S): During the 12 months after surgery, two women who received the Filshie Clip and two women who received the Tubal Ring became pregnant, giving a 12-month life-table pregnancy probability of 1.7 per 1000 women in both groups. The Tubal Ring was more difficult to apply and had higher rates of tubal or mesosalpingeal injuries at surgery. The Filshie Clip group had three cases of spontaneous clip expulsion during the follow-up period. CONCLUSION(S): Both the Filshie Clip and Tubal Ring are effective and safe for use in tubal occlusion.

Adult↗
PubMed2005

Image documentation of endoscopic findings in ulcerative colitis: photographs or video clips?

BACKGROUND: Previous studies have shown deficiencies in the endoscopy reports and substantial interobserver variation in the assessments of endoscopic findings. The aim of this study was to determine how to perform systematic digital image documentation in ulcerative colitis and to evaluate if mucosal inflammation is assessed equally on a still image and on a video clip. METHODS: Eighteen video clips and their corresponding photographs that visualize different severities of ulcerative colitis were shown in randomized order to 20 experienced endoscopists. They assessed the mucosal inflammation of each image twice on a visual analog scale. Three comparisons were performed between the video clips, the photographs, and the video clips to the photographs, respectively. RESULTS: The mean score of the inflammation of the video clips at tape 1 and 2 was 4.74: 95% confidence interval (CI)[4.41, 5.08] and 4.90: 95% CI[4.56, 5.24), respectively, and of the photographs 4.53: 95% CI[4.19, 4.88] and 4.43: 95% CI[4.09, 4.77], respectively. The first answer explains 83% of the variation in the second answer for all comparisons, and the agreement index ranged from 0.38 to 0.42. CONCLUSIONS: The mucosal inflammation might be documented nearly as well with a still image as on a video clip. Systematic use of still images probably improves the endoscopy reports by adding more objective information about the mucosal inflammation.

Colitis, Ulcerative↗
PubMed1999

A novel clinical application for endoscopic mucosal clipping.

BACKGROUND: Endoscopic hemoclipping has been shown to be effective in the treatment of gastrointestinal bleeding. Here we describe a novel clinical application for endoscopic application of metal clips. METHODS: A middle-aged man with inoperable squamous cell cancer of the esophagus underwent per protocol a barium esophagogram to document tumor margins prior to radiation therapy. This study failed to localize the full extent of the tumor. At endoscopy, the tumor margins were clearly visible. To delineate the proximal and distal margins, detachable metallic clips were passed through the accessory channel of a standard endoscope and using a clip fixing device the clips were placed at each level. Subsequently, a chest x-ray was obtained. RESULTS: Placement of mucosal clips facilitated radiotherapy. CONCLUSIONS: Endoscopic mucosal clipping may serve as a useful technique for localizing or marking gastrointestinal lesions, especially for demarcating a precise radiation field when conventional techniques fail.

Carcinoma, Squamous Cell↗
PubMed1999

New semicircular clip for internal carotid artery aneurysms. Technical note.

BACKGROUND: Complete clipping of internal carotid artery (ICA) aneurysms without residual aneurysmal neck may conflict with preservation of the anterior choroidal artery, posterior communicating artery, or their branches. In addition, the neck of the aneurysm is often situated behind the ICA, as seen through the operative microscope. The blades of fenestrated clips can be inserted over the ICA, followed by reconstruction of the ICA wall to minimize the residual aneurysmal neck. However, the blades are out of the field of vision behind the ICA when they are closed, so that ICA branches or perforators may be clipped together with the aneurysmal neck. We have developed a semicircular clip to avoid this type of misclipping. METHODS AND RESULTS: We have treated four patients with ruptured ICA aneurysms and two patients with unruptured ICA aneurysms with this semicircular clip. In all cases, the aneurysms were clipped without residual neck, and the ICA branches were preserved. CONCLUSION: This instrumentation is especially useful in cases of ICA aneurysms protruding posteriorly or medially.

Carotid Artery, Internal↗
PubMed2002

Rac1 and Cdc42 capture microtubules through IQGAP1 and CLIP-170.

Linkage of microtubules to special cortical regions is essential for cell polarization. CLIP-170 binds to the growing ends of microtubules and plays pivotal roles in orientation. We have found that IQGAP1, an effector of Rac1 and Cdc42, interacts with CLIP-170. In Vero fibroblasts, IQGAP1 localizes at the polarized leading edge. Expression of carboxy-terminal fragment of IQGAP1, which includes the CLIP-170 binding region, delocalizes GFP-CLIP-170 from the tips of microtubules and alters the microtubule array. Activated Rac1/Cdc42, IQGAP1, and CLIP-170 form a tripartite complex. Furthermore, expression of an IQGAP1 mutant defective in Rac1/Cdc42 binding induces multiple leading edges. These results indicate that Rac1/Cdc42 marks special cortical spots where the IQGAP1 and CLIP-170 complex is targeted, leading to a polarized microtubule array and cell polarization.

Actins↗
PubMed1998

The CLIP-substituted invariant chain efficiently targets an antigenic peptide to HLA class II pathway in L cells.

The presentation of antigenic peptides by major histocompatibility complex (MHC) class II to CD4+ T cells is crucial to initiate immune responses. We developed a new system for delivery of an antigenic peptide to the MHC class II pathway, using the invariant chain (Ii). We designed a mutated human p33-form Ii, CLIP-substituted Ii, in which streptococcal M12p55-68 (RDLEQAYNELSGEA) was substituted for CLIP (class II associated invariant chain peptide). We examined the peptide presenting function of this construct, in comparison with the previously reported C-terminal fused Ii, in which a cathepsin cleavage site and M12p54-68 was ligated to the C-terminus of Ii. Mouse L cell transfectants expressing either of these two mutated Ii along with HLA-DR4 could process and present M12p55-68 to the peptide specific and DR4-restricted CD4+ T cell clone. CLIP-substituted Ii was much more efficient in antigen presentation than was the C-terminal fused Ii. Similar to the wild-type Ii, the CLIP-substituted Ii was associated intracellularly with DR4 molecules. These results indicate that the peptide substituted for CLIP of Ii p33 bound to the groove of DR molecules in the same manner as CLIP and it was preferentially presented to the CD4+ T cell clone in the absence of HLA-DM molecules. This system may prove useful for immunotherapy with DNA vaccines or for construction of an antigen presenting cell library with diverse peptides.

Amino Acid Sequence↗
PubMed1997

Arterial and venous repair with vascular clips: comparison with suture closure.

PURPOSE: Nonpenetrating, arcuate-legged titanium vascular closure staple (VCS) clips were initially developed for microvascular anastomoses with little experience of their use in larger vessels. The purpose of this study was to compare the VCS clips with standard suture closure of arteriotomies and venotomies in common iliac vessels of pigs. METHODS: In nine pigs, longitudinal 1 cm iliac arterial and venous incisions were repaired with VCS clips on one side and continuous 6-0 polypropylene suture on the other, and the macroscopic and microscopic results were assessed after 3 months. RESULTS: The time required for vessel repair was significantly shorter with clips than with sutures both in arteries (51 +/- 9 vs 414 +/- 36 seconds) and in veins (100 +/- 32 vs 439 +/- 45 seconds). There was no significant difference in the inner diameter, intimal thickness, or intima-to-media height ratios of the arteries or veins after either method of closure. CONCLUSIONS: Repair of 1 cm incisions in small-diameter arteries and veins with VCS clips results in wound healing as good as that achieved with standard suture closure, when assessed for patency, leakage, degree of narrowing, and intimal reaction. The time required for clip closure is considerably shorter than for suture closure.

Animals↗
PubMedDate not supplied

Preparation of a spermine conjugate of the bis-phenanthroline ligand Clip-Phen and evaluation of the corresponding copper complex.

We described the synthesis of conjugates of N, N-diethylethylenediamine and spermine with Clip-Phen, a new ligand with two 1,10-phenanthrolines linked by serinol. The ability of the copper complexes of these Clip-Phen conjugates to cleave PhiX174 DNA when activated by a reductant in the presence of air was compared to that of 1,10-phenanthroline copper complexes. The results indicated that Clip-Phen-spermine with copper was the most active DNA cleaver. Comparison with a conjugate having only one phenanthroline unit linked to spermine showed that the high activity of Clip-Phen-spermine-Cu was not only due to the presence of spermine, which increases the affinity of the Clip-Phen entity for the DNA, but was effectively due to the presence of the two bridged phenanthroline entities. The DNA cleavage activity of (Clip-Phen-spermine)CuCl2 was analyzed on a 167 bp restriction fragment and a 45-mer double-stranded oligonucleotide.

Bacteriophage phi X 174↗
PubMed2004

Upregulation of the CLIP self peptide on mature dendritic cells antagonizes T helper type 1 polarization.

Dendritic cells (DCs) initiate and regulate immunity against foreign and self antigens. Here we identified more than 200 individual major histocompatibility complex class II-associated peptides on human DCs and found that mature DCs selectively upregulated the self peptide CLIP. CLIP cosegregated together with foreign antigenic peptides in tetraspan microdomains on the surface and localized to DC-T cell synapses. The increased representation of CLIP-major histocompatibility complex class II complexes favored polarization of autologous naive T cells toward the nonpolarized and T helper type 2 (T(H)2) phenotype. There was also a considerably higher T(H)2/T(H)1 ratio in H2-DM-deficient mice, which have a CLIP(hi) phenotype, in contrast to wild-type, CLIP(lo) mice. Thus, the self peptide CLIP on DCs qualifies as an endogenous regulator in priming of T helper cells by antagonizing the polarization toward the T(H)1 phenotype.

Antigen Presentation↗