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At least 37 records · Page 2Linked to original sources
PubMed1997

Postoperative spiral computed tomography and magnetic resonance angiography after aneurysm clipping with titanium clips.

OBJECTIVE: To reduce morbidity and mortality after subarachnoid hemorrhage, it is imperative to evaluate the results of the surgical treatment of cerebral aneurysms. We investigated the usefulness of spiral computed tomography (CT) and magnetic resonance angiography as postoperative control examinations after cerebral aneurysms were clipped with titanium clips. METHODS: Eleven patients with 13 treated aneurysms were studied prospectively with postoperative digital subtraction angiography, spiral CT, and magnetic resonance angiography. The occlusion of the dome of the aneurysm, the presence of a remnant of the neck, the patency of the parent vessels and other major vessels, and the presence of vasospasm were investigated. RESULTS: The different parameters could all be well evaluated by postoperative spiral CT. The artifacts caused by the titanium clips, although relatively small compared with artifacts from other clips, precluded evaluating the dome and the neck of the aneurysm with magnetic resonance angiography. CONCLUSION: In our opinion, spiral CT promises to become a valuable aid in in the postoperative evaluation of clipped aneurysms, and we recommend its routine performance. Postoperative digital subtraction angiography remains the gold standard and has to be performed when spiral CT reveals abnormalities, when the neck of the aneurysm cannot be evaluated because the clip overlays it, or when, intraoperatively, imperfect clipping is suspected and intraoperative angiography cannot be performed.

Adolescent↗
PubMed1999

[A case of aneurysmal neck clipping following incomplete neck clipping and coil embolization].

We report a case with radical neck clipping following incomplete embolization with coils and imperfect neck clipping. A 43-year-old woman suffered from a subarachnoid hemorrhage (Hunt & Hess Grade IV) due to the rupture of a left paraclinoid internal carotid aneurysm on 28 October, 1996. Neck clipping of the aneurysm was performed at day 1. Follow-up angiogram at 2 weeks after surgery showed however a small residual aneurysm. The second angiogram 1.5 months later showed the growth of the residual aneurysm. The residual part of the aneurysm was then treated with endovascular embolization using interlocking detachable coils (IDC), resulting in incomplete occlusion of the aneurysm. The direct surgical clipping of the residual aneurysm was performed via Dolenc approach. A fenestrated clip was applied to the partial embolized aneurysm, when the aneurysmal wall was ruptured between the occluded part of the aneurysm and the residual dome. The fenestrated clip was then reapplied successfully under temporary occlusion of the parent artery. Because of the stenosis of the parent artery, STA-MCA anastomosis was then performed. Postoperative recovery of the patient was uneventful and postoperative angiogram showed stenosis of the parent artery with patent bypass flow. The patient was discharged without complications. Technical problems in neck clipping following incomplete embolization with coils are discussed.

Adult↗
PubMed1986

Impairment and recovery of the clipped kidney in two kidney, one clip hypertensive rats during and after antihypertensive therapy.

Earlier experiments have shown that in sodium depleted hypertensive rats with bilaterally constricted renal arteries the arterial pressure normalized after blockade of the renin-angiotensin system; simultaneously acute renal failure occurred. In hypertensive rats with unilateral renal artery stenosis an impaired excretory function of the clipped kidney can be expected, but may not be detectable by conventional tests of renal function. Male Wistar rats with chronic two kidney, one clip hypertension were fed a low sodium diet. After 7 days the rats were treated with vehicle, with the vasodilator dihydralazine, or with the angiotension converting enzyme inhibitor MK 421 for 2 weeks. During the 14-day treatment period a continuous blood pressure reduction was achieved in dihydralazine and MK 421 treated rats. Overall excretory kidney function (plasma creatinine concentration) was well maintained in all three groups until the end of the antihypertensive drug treatment. At the end of drug therapy mean glomerular filtration rates of the left clipped kidneys were significantly lower in both treated groups compared to hypertensive controls, and mean glomerular filtration rate of the left clipped kidneys of dihydralazine treated rats was significantly higher than in MK 421 treated rats: controls (N = 6) 1.03 +/- 0.03, dihydralazine-group (N = 10) 0.28 +/- 0.07, MK 421-group (N = 9) 0.03 +/- 0.01 ml/min. Renal blood flows were comparable in both treated groups. Only the left kidneys of rats treated with MK 421 showed a prominent tubular atrophy. Seven days after declipping of the left renal artery and right nephrectomy a considerable restitution of the tubular structure had occurred in the MK 421-group. The recovery of tubular epithelial cells was paralleled by a rise in glomerular filtration rate: MK 421 group (N = 7) 1.25 +/- 0.08 ml/min. Thus, the clipped kidney in two kidney, one clip hypertensive rats showed functional and morphological signs of impairment when systemic arterial pressure was reduced to the normal range. The alterations of the clipped kidney were most pronounced in rats with renin-angiotensin system-blockade.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2005

Crystal structure of a clip-domain serine protease and functional roles of the clip domains.

Clip-domain serine proteases (SPs) are the essential components of extracellular signaling cascades in various biological processes, especially in embryonic development and the innate immune responses of invertebrates. They consist of a chymotrypsin-like SP domain and one or two clip domains at the N-terminus. Prophenoloxidase-activating factor (PPAF)-II, which belongs to the noncatalytic clip-domain SP family, is indispensable for the generation of the active phenoloxidase leading to melanization, a major defense mechanism of insects. Here, the crystal structure of PPAF-II reveals that the clip domain adopts a novel fold containing a central cleft, which is distinct from the structures of defensins with a similar arrangement of cysteine residues. Ensuing studies demonstrated that PPAF-II forms a homo-oligomer upon cleavage by the upstream protease and that the clip domain of PPAF-II functions as a module for binding phenoloxidase through the central cleft, while the clip domain of a catalytically active easter-type SP plays an essential role in the rapid activation of its protease domain.

Amino Acid Sequence↗
PubMed2005

Surgical clips found at the hepatic duct after laparoscopic cholecystectomy: a possible case of clip migration.

Surgical clip migration and subsequent stone formation in the common bile duct is a rare but well-established complication after laparoscopic cholecystectomy. There are some suggestions about the mechanisms of the migration process, but the details are still unclear. We report here a case in which common bile duct stones were formed around surgical clips, and other clips were found to have penetrated into the common hepatic duct, which we believe were in the process of migration after laparoscopic cholecystectomy. The patient required a laparotomy to retrieve the bile duct stones due to the distal stricture, and another laparotomy was necessary to remove the penetrating clips, which were deeply embedded in the bile duct wall. Although a variety of endoscopic and percutaneous interventional procedures are available in this era of modern medical technology, it is sometimes impractical to apply these procedures in such cases as ours, and exploratory laparotomy is sometimes required to correctly treat the patient. This case shows that the metallic surgical clips can penetrate into the intact bile duct wall through serial maceration, and we believe that careful application of clips may be the only way to prevent their migration after laparoscopic cholecystectomy.

Cholecystectomy, Laparoscopic↗
PubMed2002

Altered expression of Na(+)/H(+) exchanger isoforms 1 and 3 in clipped and unclipped kidneys of a 2-kidney-1-clip Goldblatt model of hypertension.

BACKGROUND: Functional differences between the clipped and unclipped kidneys in a 2-kidney-1-clip (2K-1C) hypertension model have been reported. However, the molecular basis of these changes is poorly understood. OBJECTIVES: Expression of NHE-1 and NHE-3 isoforms and sodium pump activity (PNP), and their modulation by blood pressure (BP), PGE(2) and TXB(2) were examined in the kidneys of 2K-1C rats treated with cilazapril for short- (4 and 24 h) and long-term (7 days) periods. METHODS: 2K-1C rats were divided into two groups. Group 1 (short-term) animals were treated with a single dose of cilazapril for 4 or 24 h. Group 2 (long-term) animals received a daily dose of cilazapril for 7 days. 2K-1C animals receiving water served as clipped controls, and sham-operated animals were normal controls. Western blot analysis was used to estimate the protein levels and ELISA for PGE(2) and TXB(2). RESULTS: Levels of NHE-1 and NHE-3 protein in the unclipped kidneys of both treatment groups were increased, whereas levels of alpha-actin, PNP activity and crude microsomes remained unchanged. These changes were significantly reduced by long-term, and not by short-term treatment with cilazapril. In group 1 clipped kidneys, NHE-3 and alpha-actin proteins were increased, and crude microsomes and PNP activity were decreased. In group 2 clipped kidneys, both NHE-1 and 3 isoforms were induced, whereas PNP activity was decreased. Cilazapril did not reverse the changes in the clipped kidneys in both groups, but reduced the crude microsomes. Group 2 unclipped kidneys showed hypertrophy, which remained unaffected by cilazapril treatment. Induced levels of BP, PGE(2) and TXB(2) in both groups were reduced significantly except for the 24-hour post-cilazapril treatment. CONCLUSIONS: These findings demonstrate a differential expression of NHE-1 and NHE-3 isoforms which is dependent on the rise in BP, PGE(2) or TXB(2) in the long-term treatment group, but not in the short-term treatment group. Thus, the changes in NHE isoforms and sodium pump activity, together, contribute to functional differences that exist in the 2K-1C kidneys.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1976

Endothelial cell damage by temporary arterial occlusion with surgical clips. Study of the clip site by scanning and transmission electron microscopy.

The effects of temporary vascular occlusion with surgical clips on the underlying endothelial lining were studied with scanning (SEM) and transmission (TEM) electron microscopy. Twenty-five rabbits were anesthetized and both common carotid arteries exposed. A Heifetz clip was used to occlude the right carotid artery for 5, 15, and 30 minutes, and 2 hours in five animals each. The clips were removed and the vessels immediately perfused with glutaraldehyde. In five remaining animals, the right carotid arteries were occluded for 30 minutes followed by removal of the clip and resumption of blood flow for 30 minutes prior to fixation. Combined SEM and TEM examination of the endothelium of compressed segments revealed "craters" and "balloons", blebs and vacuoles, swollen mitochondria, dilated granular endoplasmic reticulum, and subendothelial edema. There were also areas of endothelial cell flattening, discontinuity, and desquamation exposing the subendothelial tissues. Following restoration of flow, platelets and fibrin were found adherent to altered endothelial cells and to exposed subendothelial tissues. Endothelial craters and balloons were also found distal and, significantly less frequently, proximal to the site of occlusion. It is suggested that antiplatelet aggregating agents may prove beneficial for the prevention of thrombus formation at the site of the clip as well as craters and balloons distal to the clip following procedures requiring temporary vascular occlusion.

Animals↗
PubMed1984

Study of renovascular hypertension in rats: I. The role of the contralateral, non-clipped kidney in two-kidney, one-clip hypertension in rats.

We attempted to produce two-kidney one-clip renovascular hypertension in SD rats, using hemoclips 0.2mm in diameter. After 12 weeks, 10 of the 16 rats were hypertensive. At this point, one-kidney, one-clip models were prepared by contralateral nephrectomy in five of the 10 hypertensive rats and in all six normotensive rats. Postoperatively, these 11 rats developed hypertension. Four to 6 weeks later, the clip was removed from the renal artery in five two-kidney and 11 one-kidney hypertensive rats. After unclipping, all the rats became normotensive although the extent of the fall in blood pressure in the one-kidney model was significantly greater than in the two-kidney model. The roles of the contralateral non-clipped kidney in the evolution of two-kidney, one-clip Goldblatt hypertension appear to be dual; sometimes depressing elevated blood pressure and sometimes maintaining it. Thus, it is postulated that in the six initially normotensive rats, its action was predominantly antihypertensive, while in the other 10 hypertensive rats, the presence of a contralateral non-clipped kidney served to develop and maintain hypertension even after unclipping.

Angiotensin II↗
PubMed1980

[Postoperative transient occlusion of internal carotid artery due to shift of the clip used for neck clipping of the huge left internal carotid aneurysm (author's transl)].

A 49-year-old female, having had suffered from a huge left internal carotid (IC) aneurysm and a right IC aneurysm, was treated surgically. The neck of huge aneurysm, was treated surgically. The neck of huge aneurysm was clipped with Sugita's spring clip after its body was dissected and the otherone was clipped simply. Right hemiparesis was seen postoperatively. And the angiograms, taken on the 4th postoperative day, showed not only an aneurysmal disappearance but also an occlusion of the left ICA which presumably due to shift of the spring clip to the direction of antero-lateral. Right hemiparesis disappeared, however, suddenly on the 40th postoperative day and reopening of the left ICA was confirmed angiographically despite the further shift of the clip. The possible genesis of the curious course in this case and the possible complications in the use of large aneurysmal clip was discussed.

Carotid Artery Diseases↗
PubMed2006

Fabrication of custom clips for bar-and-clip attachments for implant-supported overdentures.

Bar-and-clip attachments for dental implants are a common and versatile device for improving the retention and stability of a removable prosthesis. Manufactured clips may be unsubstantial and may not always fit or provide the desired amount of retention for the bar. The purpose of this article is to describe a technique for custom fabrication of clip attachments. The wax pattern of the clips is fabricated and then cast in dental gold alloy. The gold clips are then cut to an appropriate size that will allow for a variety of clinical applications.

Dental Casting Technique↗
PubMed1985

Biological tolerance to polydioxanone absorbable clips: a comparison with metallic ligating clips.

An experiment was conducted in 96 rats to determine the tissue tolerance to a hemostatic and absorbable clip made of polydioxanone, as compared to standard metallic clips. Clinical tolerance was similar and no bleeding or death occurred because of the material. Pathological studies showed a mild histiocytic reaction with absorbable clips and a stronger inflammatory reaction with metallic clips. This experiment indicates that absorbable clips are efficient and well tolerated and we strongly recommend the use of this material.

Absorption↗
PubMed1983

Effect of clonidine on blood pressure in chronic one-kidney, one-clip and two-kidney, one-clip hypertensive rats.

Oral administration of clonidine lowered the high blood pressure in two-kidney, one-clip hypertensive rats in chronic stage (three to four months), but not in one-kidney, one-clip hypertensive rats. This reduction of blood pressure was well correlated with decrease in plasma renin concentration, but not with decrease in urinary noradrenaline excretion. These results suggest that the reduction of blood pressure in two-kidney, one-clip hypertensive rats may be due to reduced renin release through the action of clonidine, while in one-kidney, one-clip hypertensive rats the sympathetic nervous activity may play little or no role in the maintenance of high blood pressure.

Animals↗
PubMed1985

Biocompatibility analysis of the Sundt-Kees booster clip and the Drake aneurysm clip. Technical note.

A combination of the Sundt-Kees reinforcing aneurysm clip applied to a Drake aneurysm clip in a piggyback fashion was studied for possible defects due to corrosion and or tissue toxicity. These two clips, which are made of similar metal (301 stainless steel), showed little or no defects when immersed in 5% saline or when implanted in rats for 6 months. This study demonstrates that clips made of similar metals can be used piggyback in patients without ill effects provided that they are carefully handled to avoid any abrasion or misbends which could conceivably lead to corrosion.

Animals↗
PubMed2000

Risk of intraoperative aneurysm clip slippage: a new experience with titanium clips.

Slippage of an aneurysm clip as a result of insufficient clip-closing force cannot be predicted, even when using force-testing devices. Descriptions of intraoperative clip slippages are rarely found in the literature. The authors summarize four unusual cases in which titanium aneurysm clips slipped by a scissorslike mechanism during surgery. They analyze the possible factors implicated in such a dangerous situation and discuss corrective choices.

Aneurysm, Ruptured↗
PubMed2001

Anastomosis of vessels less than 2 mm with the vascular clip system clip applier.

Sutures may cause endothelial trauma and occlusion. The vascular clip system (VCS) clip applier may minimize endothelial injury. Fourteen carotid arteries of nine adult rabbits were transected and re-anastomosed with either #7-0 polypropylene (Group I, n=8) or VCS clips (Group II, n=6). The animals were sacrificed at 1, 3, 8, 14, and 30 days postoperatively. The operation time and bleeding amount were checked for each anastomosis. Carotid angiograms, photography, H&E staining and scanning electron microscopy (SEM) were performed. Fibrin and thrombus, inflammatory cell infiltration, endothelial disruption, luminal distortion, fibrosis, and wall thickening were compared. The luminal diameter was greater in group II. There were minimal differences in thrombosis, wall thickening and fibrosis between the two groups. However, fibrin, inflammatory cell infiltration, multinucleated giant cell formation, endothelial disruption, and luminal distortion were greater in group I. On SEM, group I showed trans-mural penetration. In contrast, group II showed suture margin eversion and no transmural penetration. Stenosis was greater in group I than in group II on carotid angiogram. The operation time was shorter in group II than in group I, i.e. 5+/-1.4 min vs. 11+/-3.8 min, respectively. The current data showed similar or superior results with VCS clips in comparison to conventional suturing with polypropylene.

Angiography↗
PubMed1990

Haemostatic clips and clamps used in surgical neurology with special reference to non ferro magnetic Phynox spring clips by Aesculap.

This paper concerns the historical developments and technical properties of haemostatic devices used in neurosurgery with the exception of coagulation. Therefore there are described haemostatic clips designed for the scalp, clips used on arteries and veins, a clamp for the reduction of the carotid diameter in the neck, and a clamp for closing the venous dural sinuses. Special reference will be made regarding non ferro magnetic Phynox clips by Aesculap.

Hemostasis, Surgical↗